| 1. |
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| 2. |
- Luo, Yifei, et al.
(författare)
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Technology Roadmap for Flexible Sensors
- 2023
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Ingår i: ACS Nano. - : American Chemical Society. - 1936-0851 .- 1936-086X. ; 17:6, s. 5211-5295
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Forskningsöversikt (refereegranskat)abstract
- Humans rely increasingly on sensors to address grand challenges and to improve quality of life in the era of digitalization and big data. For ubiquitous sensing, flexible sensors are developed to overcome the limitations of conventional rigid counterparts. Despite rapid advancement in bench-side research over the last decade, the market adoption of flexible sensors remains limited. To ease and to expedite their deployment, here, we identify bottlenecks hindering the maturation of flexible sensors and propose promising solutions. We first analyze challenges in achieving satisfactory sensing performance for real-world applications and then summarize issues in compatible sensor-biology interfaces, followed by brief discussions on powering and connecting sensor networks. Issues en route to commercialization and for sustainable growth of the sector are also analyzed, highlighting environmental concerns and emphasizing nontechnical issues such as business, regulatory, and ethical considerations. Additionally, we look at future intelligent flexible sensors. In proposing a comprehensive roadmap, we hope to steer research efforts towards common goals and to guide coordinated development strategies from disparate communities. Through such collaborative efforts, scientific breakthroughs can be made sooner and capitalized for the betterment of humanity.
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| 3. |
- Deng, Min, et al.
(författare)
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Genome-wide association analyses in Han Chinese identify two new susceptibility loci for amyotrophic lateral sclerosis
- 2013
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Ingår i: Nature Genetics. - : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 45:6, s. 697-
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Tidskriftsartikel (refereegranskat)abstract
- To identify susceptibility genes for amyotrophic lateral sclerosis (ALS), we conducted a genome-wide association study (GWAS) in 506 individuals with sporadic ALS and 1,859 controls of Han Chinese ancestry. Ninety top SNPs suggested by the current GWAS and 6 SNPs identified by previous GWAS were analyzed in an independent cohort of 706 individuals with ALS and 1,777 controls of Han Chinese ancestry. We discovered two new susceptibility loci for ALS at 1q32 (CAMK1G, rs6703183, P-combined = 2.92 x 10(-8), odds ratio (OR) = 1.31) and 22p11 (CABIN1 and SUSD2, rs8141797, P-combined = 2.35 x 10(-9), OR = 1.52). These two loci explain 12.48% of the overall variance in disease risk in the Han Chinese population. We found no association evidence for the previously reported loci in the Han Chinese population, suggesting genetic heterogeneity of disease susceptibility for ALS between ancestry groups. Our study identifies two new susceptibility loci and suggests new pathogenic mechanisms of ALS.
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| 4. |
- Dai, Ting, et al.
(författare)
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Assessment of Fast Fluid Dynamics with Different Turbulence Models for Simulating Airflow and Pollutant Dispersion Around Buildings
- 2023
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Ingår i: Proceedings of the 5th International Conference on Building Energy and Environment. - : Springer Nature. ; , s. 51-59
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Konferensbidrag (refereegranskat)abstract
- Fast fluid dynamics (FFD) could provide efficient airflow and concentration simulation. The commonly used turbulence model in FFD was RNG k- ε turbulence model which solved two transport equations to obtain eddy viscosity. To improve computing speed, this investigation implemented no turbulence model, Smagorinsky model and dynamic Smagorinsky model which calculated eddy viscosity without solving equation in FFD in an open-source program, OpenFOAM. By simulating single-building case and comparing with experiment and CFD, this study assessed accuracy and efficiency of FFD with those turbulence models. Compared with CFD, FFD improved computing speed without reducing accuracy. The simulation of FFD without turbulence model was fast but inaccurate. FFD with Smagorinsky model increased computing speed while ensuring the same accuracy as RNG k- ε turbulence model. FFD with dynamic Smagorinsky model provided accurate results with high efficiency. This investigation suggested FFD with dynamic Smagorinsky model for outdoor airflow and pollutant dispersion studies.
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| 5. |
- Dai, Ting, et al.
(författare)
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Evaluation of fast fluid dynamics with different turbulence models for predicting outdoor airflow and pollutant dispersion
- 2022
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Ingår i: Sustainable cities and society. - : Elsevier BV. - 2210-6707. ; 77, s. 103583-
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Tidskriftsartikel (refereegranskat)abstract
- Fast fluid dynamics (FFD) could provide informative and efficient airflow and concentration simulation. The commonly used turbulence model in FFD was Re-Normalization Group (RNG) k-epsilon turbulence model which solved two transport equations to obtain eddy viscosity. To reduce this part of time and further improve computing speed, this investigation implemented no turbulence model, Smagorinsky model and dynamic Smagorinsky model which calculated eddy viscosity without solving equation in FFD in an open-source program, OpenFOAM. By simulating several outdoor cases of varying complexity and comparing with experiment and CFD, this study assessed the accuracy and computing efficiency of FFD with four turbulence models. Compared with CFD, FFD greatly improved the computing speed without reducing accuracy. The simulation of FFD without turbulence model was fast but inaccurate. FFD with Smagorinsky model increased the computing speed while ensuring the same accuracy as RNG k-epsilon turbulence model. FFD with dynamic Smagorinsky model provided accurate results with high efficiency. Computation errors arose mainly from inaccurate prediction of turbulence dispersion. The computing cost was associated with the number of transport equations and calculation method of model coefficient. This investigation recommended the use of FFD with dynamic Smagorinsky model for outdoor airflow and pollutant dispersion studies.
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| 6. |
- Li, Guowei, et al.
(författare)
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Carbon-Tailored Semimetal MoP as an Efficient Hydrogen Evolution Electrocatalyst in Both Alkaline and Acid Media
- 2018
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Ingår i: Advanced Energy Materials. - : WILEY-V C H VERLAG GMBH. - 1614-6832 .- 1614-6840. ; 8:24
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Tidskriftsartikel (refereegranskat)abstract
- The electrolysis processes such as hydrogen evolution reaction (HER) require high efficient catalysts with robust surface stability. A high conductivity is also necessary to speed up the charge transport between the catalyst and the electrolyte. Recently, the observation of exceedingly high conductivity in the topological semimetal MoP, has provided a model catalyst to investigate the correlation between the electrical transport and the electrocatalytic activity for the HER. Thus, MoP is encapsulated in a Mo, P codoped carbon layer (MoP@C). This composite material exhibits outstanding HER performance, with an extremely low overpotential of 49 mV at a current density of 10 mA cm(-2) and a Tafel slope of 54 mV dec(-1) in an alkaline medium. In addition, electron transport analysis indicates that MoP exhibits high conductivity and mobility due to the existence of triple-point fermions and a complex Fermi surface. Furthermore, the presence of P-C and Mo-C bonds at the interface between the carbon layer and the MoP particles modulates the band structure of MoP@C and facilitates fast electron transfer, accumulation, and subsequent delocalization, which are in turn responsible for the excellent HER activity.
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| 7. |
- Liang, Xiaoyan, et al.
(författare)
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Association and interaction of TOMM40 and PVRL2 with plasma amyloid-β and Alzheimer's disease among Chinese older adults : a population-based study
- 2022
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 113, s. 143-151
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Tidskriftsartikel (refereegranskat)abstract
- Genetic studies have identified Alzheimer's disease (AD)-associated SNPs in TOMM40 and PVRL2 genes, but the underlying mechanisms remain unknown. We examined their associations and interactions with AD risk and plasma biomarkers among Chinese older adults. This population-based study included 4876 participants. TOMM40(rs2075650) and PVRL2(rs6859) polymorphisms were detected using multiple-polymerase chain reaction amplification. Plasma Aβ40, Aβ42, and t-tau concentrations were measured using SIMOA in a subsample (n = 1257). AD was diagnosed following the international criteria. Data were analyzed using multiple logistic and general linear models. AD was diagnosed in 182 participants. The multiadjusted odds ratio of AD was 6.24 (95% CI 1.73–22.48) for TOMM40GG, 1.47 (0.89–2.42) for PVRL2AA, and 12.87 (3.97–41.73) for having both risk alleles (Pinteraction = 0.0003). Among APOEε3/ε3 carriers, the multiadjusted odds ratio of AD associated with TOMM40AG was 2.90(1.15–7.31). In biomarker subsample, TOMM40GG was significantly associated with lower plasma Aβ42 and the Aβ42-to-Aβ40 ratio (p < 0.05). TOMM40 genotype is differentially associated with AD risk depending on APOE genotype. TOMM40 and PVRL2 genes could interact to substantially increase AD risk, possibly through influencing Aβ metabolism.
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| 8. |
- Liu, Yang, et al.
(författare)
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Genome Assembly of the Common Pheasant Phasianus colchicus : A Model for Speciation and Ecological Genomics
- 2019
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Ingår i: Genome Biology and Evolution. - : Oxford University Press (OUP). - 1759-6653. ; 11:12, s. 3326-3331
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Tidskriftsartikel (refereegranskat)abstract
- The commonpheasant (Phasianus colchicus) in the order Galliformes and the family Phasianidae, has 30 subspecies distributed across its native range in the Palearctic realm and has been introduced to Europe, NorthAmerica, and Australia. It is an important game bird often subjected to wildlife management as well as a model species to study speciation, biogeography, and local adaptation. However, the genomic resources for the commonpheasant are generally lacking. We sequenced a male individual of the subspecies torquatus of the common pheasant with the Illumina HiSeq platform. We obtained 94.88Gb of usable sequences by filtering out low-quality reads of the raw data generated. This resulted in a 1.02Gb final assembly, which equals the estimated genome size. BUSCO analysis using chicken as a model showed that 93.3% of genes were complete. The contig N50 and scaffold N50 sizes were 178 kb and 10.2 Mb, respectively. All these indicate that we obtained a high-quality genome assembly. We annotated 16,485 protein-coding genes and 123.3 Mb (12.05% of the genome) of repetitive sequences by ab initio and homology-based prediction. Furthermore, we applied a RAD-sequencing approach for another 45 individuals of seven representative subspecies in China and identified 4,376,351 novel single nucleotide polymorphism (SNPs) markers. Using this unprecedented data set, we uncovered the geographic population structure and genetic introgression among common pheasants in China. Our results provide the first high-quality reference genome for the common pheasant and a valuable genome-wide SNP database for studying population genomics and demographic history.
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| 9. |
- Sampson, Joshua N., et al.
(författare)
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Analysis of Heritability and Shared Heritability Based on Genome-Wide Association Studies for 13 Cancer Types
- 2015
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Ingår i: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 0027-8874 .- 1460-2105. ; 107:12
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Tidskriftsartikel (refereegranskat)abstract
- Background: Studies of related individuals have consistently demonstrated notable familial aggregation of cancer. We aim to estimate the heritability and genetic correlation attributable to the additive effects of common single-nucleotide polymorphisms (SNPs) for cancer at 13 anatomical sites. Methods: Between 2007 and 2014, the US National Cancer Institute has generated data from genome-wide association studies (GWAS) for 49 492 cancer case patients and 34 131 control patients. We apply novel mixed model methodology (GCTA) to this GWAS data to estimate the heritability of individual cancers, as well as the proportion of heritability attributable to cigarette smoking in smoking-related cancers, and the genetic correlation between pairs of cancers. Results: GWAS heritability was statistically significant at nearly all sites, with the estimates of array-based heritability, h(l)(2), on the liability threshold (LT) scale ranging from 0.05 to 0.38. Estimating the combined heritability of multiple smoking characteristics, we calculate that at least 24% (95% confidence interval [CI] = 14% to 37%) and 7% (95% CI = 4% to 11%) of the heritability for lung and bladder cancer, respectively, can be attributed to genetic determinants of smoking. Most pairs of cancers studied did not show evidence of strong genetic correlation. We found only four pairs of cancers with marginally statistically significant correlations, specifically kidney and testes (rho = 0.73, SE = 0.28), diffuse large B-cell lymphoma (DLBCL) and pediatric osteosarcoma (rho = 0.53, SE = 0.21), DLBCL and chronic lymphocytic leukemia (CLL) (rho = 0.51, SE = 0.18), and bladder and lung (rho = 0.35, SE = 0.14). Correlation analysis also indicates that the genetic architecture of lung cancer differs between a smoking population of European ancestry and a nonsmoking Asian population, allowing for the possibility that the genetic etiology for the same disease can vary by population and environmental exposures. Conclusion: Our results provide important insights into the genetic architecture of cancers and suggest new avenues for investigation.
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| 10. |
- Tian, Na, et al.
(författare)
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Triglyceride-glucose index, Alzheimer's disease plasma biomarkers, and dementia in older adults : The MIND-China study
- 2023
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Ingår i: Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring. - 2352-8729. ; 15:2
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Population-based studies have rarely explored the associations of the triglyceride–glucose (TyG) index, a surrogate marker of insulin resistance, with dementia and plasma biomarkers for amyloid beta (Aβ) and neurodegeneration.Methods: This population-based study included 5199 participants (age ≥ 65 years); of these, plasma Aβ, total tau, and neurofilament light chain (NfL) were measured in 1287 persons. Dementia and subtypes were diagnosed following the international criteria. TyG index was calculated as ln(fasting triglyceride(mg/dL) × fasting glucose[mg/dL]/2). Data were analyzed using logistic and general linear regression models.Results: Dementia, Alzheimer's disease (AD), and vascular dementia (VaD) were diagnosed in 301, 195, and 95 individuals, respectively. A high TyG index was significantly associated with increased likelihoods of dementia and AD; the significant association with dementia remained among participants without cardiovascular disease or diabetes. In the biomarker subsample, a high TyG index was correlated with elevated plasma Aβ, but not with total tau or NfL.Discussion: High TyG index is associated with dementia, possibly via Aβ pathology.
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| 11. |
- Chen, Shujing, et al.
(författare)
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Manufacturing Graphene-Encapsulated Copper Particles by Chemical Vapor Deposition in a Cold Wall Reactor
- 2019
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Ingår i: ChemistryOpen. - : Wiley. - 2191-1363. ; 8:1, s. 58-63
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Tidskriftsartikel (refereegranskat)abstract
- Functional fillers, such as Ag, are commonly employed for effectively improving the thermal or electrical conductivity in polymer composites. However, a disadvantage of such a strategy is that the cost and performance cannot be balanced simultaneously. Therefore, the drive to find a material with both a cost efficient fabrication process and excellent performance attracts intense research interest. In this work, inspired by the core-shell structure, we developed a facile manufacturing method to prepare graphene-encapsulated Cu nanoparticles (GCPs) through utilizing an improved chemical vapor deposition (CVD) system with a cold wall reactor. The obtained GCPs could retain their spherical shape and exhibited an outstanding thermal stability up to 179 degrees C. Owing to the superior thermal conductivity of graphene and excellent oxidation resistance of GCPs, the produced GCPs are practically used in a thermally conductive adhesive (TCA), which commonly consists of Ag as the functional filler. Measurement shows a substantial 74.6 % improvement by partial replacement of Ag with GCPs.
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| 12. |
- Cheng, Yingzhe, et al.
(författare)
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Genetic Effects of NDUFAF6 rs6982393 and APOE on Alzheimer’s Disease in Chinese Rural Elderly : A Cross-Sectional Population-Based Study
- 2022
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Ingår i: Clinical Interventions in Aging. - 1176-9092 .- 1178-1998. ; 17, s. 185-194
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To investigate the associations of genotypes of NDUFAF6 rs6982393 and APOE and their combined genotypes with the risk of Alzheimer’s disease (AD) and mild cognitive impairment (MCI) in Chinese rural elderly.Methods: This cross-sectional population-based study included 5096 older adults (age ≥ 60 years, 57.1% female). Genotypes of NDUFAF6 rs6982393 and APOE were detected using the multiple-polymerase chain reaction amplification. We diagnosed AD following the criteria of Diagnostic and Statistical Manual of Mental Disorders, the fourth edition and diagnosed MCI following the Petersen’s criteria MCI. Data were analyzed using the logistic regression model.Results: The overall prevalence of AD and MCI was 3.57% (95% confidence interval [CI]: 0.040, 0.053) and 22.65% (95% CI: 0.223, 0.247), separately. The TT versus CC/CT genotype of NDUFAF6 rs6982393 was related to a higher risk of AD with the multi-adjusted odds ratio (95% CI) being 1.61 (1.02, 2.54) in the total sample, 3.36 (1.48, 7.60) in those aged 60– 69, and 1.24 (0.71, 2.17) in those aged 70 years and above. The interaction between genotype of NDUFAF6 rs6982393 with age groups (60– 69 versus ≥ 70 years) was significant on the risk of AD. The presence of APOE ϵ4 was not significantly associated with the risk of AD. Carrying both NDUFAF6 TT and APOE ϵ4 was related to a higher risk of AD with the multi-adjusted odds ratio (95% CI) being 2.69 (1.10, 2.56). In addition, there was no significant association between the above genotypes and MCI.Conclusion: In Chinese rural elderly, the TT versus CT/CC genotype of NDUFAF6 rs6982393 was associated with an increased likelihood of AD; such an association only existed among young-old adults. Carrying both NDUFAF6 rs6982393-TT and APOE ϵ4 was related to a higher risk of AD. This finding highlights the importance of considering age and combined genotype in studying the genetic profiles of AD.
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| 13. |
- Fa, Wenxin, et al.
(författare)
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Associations of Blood Absolute Neutrophil Count and Cytokines With Cognitive Function in Dementia-Free Participants : A Population-Based Cohort Study
- 2023
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Ingår i: The journals of gerontology. Series A, Biological sciences and medical sciences. - 1079-5006 .- 1758-535X.
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Tidskriftsartikel (refereegranskat)abstract
- Background: The relationships of neutrophils and cytokines with cognitive dysfunction are poorly defined. We aimed to investigate the association of peripheral blood absolute neutrophil count (ANC) with cognitive function in older adults and to further explore the mediating role of serum cytokines in this association.Methods: This population-based cohort study included 1 666 dementia-free participants (age ≥60 years) derived from baseline examinations (March–September 2018) of the Multimodal Intervention to Delay Dementia and Disability in Rural China (MIND-China); of these, 1 087 participants completed follow-up examinations in October–December 2019. We used a neuropsychological test battery to assess episodic memory, verbal fluency, attention, and executive function at the baseline and follow-up examinations. We used Mindray BC-6800 automated hematology analyzer to measure ANC and Meso Scale Discovery to measure serum interleukin-6 (IL-6) and eotaxin-3.Results: The linear regression analysis of cross-sectional data at baseline (n = 1 666) suggested that increased ANC was significantly associated with a lower episodic memory z score (β coefficient: −0.149, 95% CI: −0.274 to −0.023) and lower long-delayed free recall z score (−0.216, −0.361 to −0.070). Serum IL-6 and eotaxin-3 could mediate 16.16% to 20.21% and 7.55% to 9.35%, respectively, of these associations. The analysis of longitudinal data (n = 1 087) showed a J-shaped relationship of ANC with decline in episodic memory z score (p for nonlinear = .049), and a U-shaped relationship between ANC and decline in long-delayed free recall z score (p for nonlinear = .043).Conclusions: Increased neutrophils are associated with poor cognitive performance and accelerated decline in episodic memory, and the cross-sectional association is partly mediated by serum cytokines.
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| 14. |
- Feng, Zhiwei, et al.
(författare)
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An Efficient UAV Hijacking Detection Method Using Onboard Inertial Measurement Unit
- 2019
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Ingår i: ACM Transactions on Embedded Computing Systems. - : ASSOC COMPUTING MACHINERY. - 1539-9087 .- 1558-3465. ; 17:6
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Tidskriftsartikel (refereegranskat)abstract
- With the fast growth of civil drones, their security problems meet significant challenges. A commercial drone may be hijacked by a GPS-spoofing attack for illegal activities, such as terrorist attacks. The target of this article is to develop a technique that only uses onboard gyroscopes to determine whether a drone has been hijacked. Ideally, GPS data and the angular velocities measured by gyroscopes can be used to estimate the acceleration of a drone, which can be further compared with the measurement of the accelerometer to detect whether a drone has been hijacked. However, the detection results may not always be accurate due to some calculation and measurement errors, especially when no hijacking occurs in curve trajectory situations. To overcome this, in this article, we propose a novel and simple method to detect hijacking only based on gyroscopes' measurements and GPS data, without using any accelerometer in the detection procedure. The computational complexity of our method is very low, which is suitable to be implemented in the drones with micro-controllers. On the other hand, the proposed method does not rely on any accelerometer to detect attacks, which means it receives less information in the detection procedure and may reduce the results accuracy in some special situations. While the previous method can compensate for this flaw, the high detection results also can be guaranteed by using the above two methods. Experiments with a quad-rotor drone are conducted to show the effectiveness of the proposed method and the combination method.
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| 15. |
- Feng, Zhiwei, et al.
(författare)
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Efficient Drone Hijacking Detection using Onboard Motion Sensors
- 2017
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Ingår i: Proceedings Of The 2017 Design, Automation & Test In Europe Conference & Exhibition (DATE). - : IEEE. - 9783981537093 ; , s. 1414-1419
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Konferensbidrag (refereegranskat)abstract
- The fast growth of civil drones raises significant security challenges. A legitimate drone may be hijacked by GPS spoofing for illegal activities, such as terrorist attacks. The target of this paper is to develop techniques to let drones detect whether they have been hijacked using onboard motion sensors (accelerometers and gyroscopes). Ideally, the linear acceleration and angular velocity measured by motion sensors can be used to estimate the position of a drone, which can be compared with the position reported by GPS to detect whether the drone has been hijacked. However, the position estimation by motion sensors is very inaccurate due to the significant error accumulation over time. In this paper, we propose a novel method to detect hijacking based on motion sensors measurements and GPS, which overcomes the accumulative error problem. The computational complexity of our method is very low, and thus is suitable to be implemented in the micro-controllers of drones. Experiments with a quad-rotor drone are conducted to show the effectiveness of the proposed method.
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| 16. |
- Feng, Zhiwei, et al.
(författare)
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Efficient drone hijacking detection using two-step GA-XGBoost
- 2020
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Ingår i: Journal of systems architecture. - : ELSEVIER. - 1383-7621 .- 1873-6165. ; 103
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Tidskriftsartikel (refereegranskat)abstract
- With the fast growth of civilian drones, their security problems meet significant challenges. A commercial drone may be hijacked by Global Positioning System (GPS)-spoofing attacks for illegal activities, such as terrorist attacks. Ideally, comparing positions respectively estimated by GPS and Inertial Navigation System (INS) can detect such attacks, while the results may always get fault because of the accumulated errors over time in INS. Therefore, in this paper, we propose a two-step GA-XGBoost method to detect GPS-spoofing attacks that just uses GPS and Inertial Measurement Unit (IMU) data. However, tunning the proper values of XGBoost parameters directly on the drone to achieve high prediction results consumes lots of resources which would influence the real-time performance of the drone. The proposed method separates the training phase into offboard step and onboard step. In offboard step, model is first trained by flight logs, and the training parameter values are automatically tuned by Genetic Algorithm (GA). Once the offboard model is trained, it could be uploaded to drones. To adapt our method to drones with different types of sensors and improve the correctness of prediction results, in onboard step, the model is further trained when a drone starts a mission. After onboard training finishes, the proposed method switches to the prediction mode. Besides, our method does not require any extra onboard hardware. The experiments with a real quadrotor drone also show the detection correctness is 96.3% and 100% in hijacked and non-hijacked cases at each sampling time respectively. Moreover, our method can achieve 100% detection correctness just within 1 s just after the attacks start.
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| 17. |
- Fu, Yifeng, 1984, et al.
(författare)
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Graphene related materials for thermal management
- 2020
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Ingår i: 2D Materials. - : IOP Publishing. - 2053-1583. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Almost 15 years have gone ever since the discovery of graphene as a single atom layer. Numerous papers have been published to demonstrate its high electron mobility, excellent thermal and mechanical as well as optical properties. We have recently seen more and more applications towards using graphene in commercial products. This paper is an attempt to review and summarize the current status of the research of the thermal properties of graphene and other 2D based materials including the manufacturing and characterization techniques and their applications, especially in electronics and power modules. It is obvious from the review that graphene has penetrated the market and gets more and more applications in commercial electronics thermal management context. In the paper, we also made a critical analysis of how mature the manufacturing processes are; what are the accuracies and challenges with the various characterization techniques and what are the remaining questions and issues left before we see further more applications in this exciting and fascinating field.
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| 18. |
- Ji, Yanan, et al.
(författare)
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Cascade photon upconversion amplification for selective multispectral narrow-band near-infrared photodetection
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Facing the fact that selective detection of multiple narrow spectral bands in the near-infrared (NIR) region still poses a fundamental challenge, we have, in this work, developed NIR photodetectors (PDs) using photon upconversion nanocrystals (UCNCs) combined with perovskite films. In order to conquer the relatively high pumping threshold of UCNCs, we designed a novel cascade amplification strategy for upconversion luminescence (UCL) through cascading the superlensing effect of dielectric microlens arrays and the plasmonic effect of gold nanorods, which readily leads to a UCL enhancement by more than four orders of magnitude under weak light irradiation. By accommodating multiple optical active lanthanide ions in a core-shell-shell hierarchical architecture, the developed PDs on top can detect three well-separated narrow bands in the NIR region, i.e., 808, 980, and 1540 nm, respectively. Due to the large UCL enhancement, the obtained PDs demonstrate extremely high responsivity of 30.73, 23.15, 12.20 A/W and detectivity of 5.36, 3.45, 1.91x10^11 Jones for the 808, 980, and 1540 nm light detection, respectively, together with short response times in the range of 80-120 ms. Moreover, we demonstrate for the first time that the response to the excitation modulation frequency of a PD can be employed to discriminate the incident light wavelength. We believe that our work provides a novel insight for developing NIR PDs, and that it can spur the development of other applications using upconversion nanotechnology.
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| 19. |
- Ji, Yanan, et al.
(författare)
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Huge upconversion luminescence enhancement by a cascade optical field modulation strategy facilitating selective multispectral narrow-band near-infrared photodetection
- 2020
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Ingår i: Light. - : SPRINGERNATURE. - 2095-5545 .- 2047-7538. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Since selective detection of multiple narrow spectral bands in the near-infrared (NIR) region still poses a fundamental challenge, we have, in this work, developed NIR photodetectors (PDs) using photon upconversion nanocrystals (UCNCs) combined with perovskite films. To conquer the relatively high pumping threshold of UCNCs, we designed a novel cascade optical field modulation strategy to boost upconversion luminescence (UCL) by cascading the superlensing effect of dielectric microlens arrays and the plasmonic effect of gold nanorods, which readily leads to a UCL enhancement by more than four orders of magnitude under weak light irradiation. By accommodating multiple optically active lanthanide ions in a core-shell-shell hierarchical architecture, developed PDs on top of this structure can detect three well-separated narrow bands in the NIR region, i.e., those centered at 808, 980, and 1540 nm. Due to the large UCL enhancement, the obtained PDs demonstrate extremely high responsivities of 30.73, 23.15, and 12.20 A W-1 and detectivities of 5.36, 3.45, and 1.91 x 10(11) Jones for 808, 980, and 1540 nm light detection, respectively, together with short response times in the range of 80-120 ms. Moreover, we demonstrate for the first time that the response to the excitation modulation frequency of a PD can be employed to discriminate the incident light wavelength. We believe that our work provides novel insight for developing NIR PDs and that it can spur the development of other applications using upconversion nanotechnology. Cascade amplified upconversion luminescence: Applied in narrow band NIR photodetection Selective detection of multiple narrow spectral bands in the near-infrared (NIR) region is still a challenge. Recently, Hongwei Song and Wen Xu at Jilin University/China, Haichun Liu at KTH Royal Institute of Technology/Sweden, and their co-workers have successfully fabricated a novel multiple NIR bands photo-detectors (PDs) by combining multiple-excitation-bands core-shell upconversion nanocrystals (UCNCs) with MAPbI(3) perovskite photoelectric conversion layer. Through a cascade optical field modulation strategy, a combination of microlenses and gold plasmon nanocrystals, the emission intensity of the UCNCs and the photoelectric signal of the PDs can be enhanced four orders of magnitude. Moreover, the excitation frequency of the PD has been employed to discriminate the wavelength of incident light for the first time. This work provides a novel insight for developing multiple bands NIR PDs, and for applications of upconversion nanotechnology.
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| 20. |
- Jones, Gareth, et al.
(författare)
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Phylogeny of new marine Dothideomycetes and Sordariomycetes from mangroves and deep-sea sediments
- 2020
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Ingår i: Botanica Marina. - : Walter de Gruyter GmbH. - 0006-8055 .- 1437-4323. ; 63:2, s. 155-181
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Tidskriftsartikel (refereegranskat)abstract
- This paper documents six new saprobic marine fungi and one new genus based on morphology and multi-gene phylogenies. Three Dothideomycetes, and members of the Pleosporales, are introduced: Pseudo-massariosphaeria triseptata sp. nov. was recognized as a mangrove species in Amniculicolaceae, and Salsuginea phoenicis sp. nov. was discovered as a second member of Salsugineaceae. A new genus Raghukumaria with Raghukumaria keshaphalae sp. nov., recovered from mangroves, is phylogenetically sister to Halomassarina and nests in the Trematosphaeriaceae. Three new species are referred to the Sordariomycetes: Coniochaeta marina (Coniochaetales, Coniochaetaceae) on driftwood; Fusicolla bharatavarshae (Hypocreales, Nectriaceae) is introduced with asexual and sexual morphs, on decayed mangrove wood of Avicennia marina; and Fusarium sedimenticola (Hypocreales, Nectriaceae) is new to the Fusarium solani species complex (FSSC) from deep-sea sediment.
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| 21. |
- Liu, Di, et al.
(författare)
-
EDF-VD scheduling of mixed-criticality systems with degraded quality guarantees
- 2016
-
Ingår i: Proc. 37th Real-Time Systems Symposium. - : IEEE Computer Society. - 9781509053032 ; , s. 35-46
-
Konferensbidrag (refereegranskat)abstract
- This paper studies real-time scheduling of mixed-criticality systems where low-criticality tasks are still guaranteed some service in the high-criticality mode, with reduced execution budgets. First, we present a utilization-based schedulability test for such systems under EDF-VD scheduling. Second, we quantify the suboptimality of EDF-VD (with our test condition) in terms of speedup factors. In general, the speedup factor is a function with respect to the ratio between the amount of resource required by different types of tasks in different criticality modes, and reaches 4/3 in the worst case. Furthermore, we show that the proposed utilization-based schedulability test and speedup factor results apply to the elastic mixed-criticality model as well. Experiments show effectiveness of our proposed method and confirm the theoretical suboptimality results.
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| 22. |
- Liu, Hao, et al.
(författare)
-
Thermally Conductive Graphene Film/Indium/Aluminum Laminated Composite by Vacuum Assisted Hot-pressing
- 2020
-
Ingår i: 2020 21ST INTERNATIONAL CONFERENCE ON ELECTRONIC PACKAGING TECHNOLOGY (ICEPT). - 9781728168265
-
Konferensbidrag (refereegranskat)abstract
- In order to meet the ever more demanding requirements of modern thermal management with the increasing high power density, an easy-fabricated laminated graphene film/indium/aluminum (GF/In/Al) composite was developed. The GF was fabricated through assemble graphene oxide (GO) sheets in a layer-by-layer structure and then subjected to graphitization process at high temperature as well as press forming process. The fabricated GF exhibits ultrahigh in-plane thermal conductivity together with good tensile strength. The GF/In/Al laminated composite was fabricated by hot-pressing indium coated GF and Al layers in vacuum environment. The indium layer was easily coated onto the GF due to its low melting point along with good flowing property. The thermal resistance measurements show that the indium bonding possess greater preponderance of reducing contact resistance than without bonding material and thermal conductive adhesive (TCA) bonding, because indium layer could fill the gap between GF and Al layers, and provide more stable connection. The results show that the obtained laminated composite could be potentially used in the thermal management of high power systems.
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| 23. |
- Liu, Nian, et al.
(författare)
-
Multi-grained Temporal Prototype Learning for Few-shot Video Object Segmentation
- 2023
-
Ingår i: 2023 IEEE/CVF INTERNATIONAL CONFERENCE ON COMPUTER VISION (ICCV 2023). - : IEEE COMPUTER SOC. - 9798350307184 - 9798350307191 ; , s. 18816-18825
-
Konferensbidrag (refereegranskat)abstract
- Few-Shot Video Object Segmentation (FSVOS) aims to segment objects in a query video with the same category defined by a few annotated support images. However, this task was seldom explored. In this work, based on IPMT, a state-of-the-art few-shot image segmentation method that combines external support guidance information with adaptive query guidance cues, we propose to leverage multi-grained temporal guidance information for handling the temporal correlation nature of video data. We decompose the query video information into a clip prototype and a memory prototype for capturing local and long-term internal temporal guidance, respectively. Frame prototypes are further used for each frame independently to handle fine-grained adaptive guidance and enable bidirectional clip-frame prototype communication. To reduce the influence of noisy memory, we propose to leverage the structural similarity relation among different predicted regions and the support for selecting reliable memory frames. Furthermore, a new segmentation loss is also proposed to enhance the category discriminability of the learned prototypes. Experimental results demonstrate that our proposed video IPMT model significantly outperforms previous models on two benchmark datasets. Code is available at https://github.com/nankepan/VIPMT.
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| 24. |
- Liu, Ya, 1991, et al.
(författare)
-
Effect of Boron Nitride Particle Geometry on the Thermal Conductivity of a Boron Nitride Enhanced Polymer Composite Film
- 2019
-
Ingår i: THERMINIC 2019 - 2019 25th International Workshop Thermal Investigations of ICs and Systems.
-
Konferensbidrag (refereegranskat)abstract
- Hexagonal Boron Nitride (h-BN) has been considered as a promising enhancement filler for thermal management due to its high thermal conductivity, structural stability, and super electrical resistivity. Numerus studies have reported using BN as an enhancement filler to achieve high thermally conductive polymer based thermal management materials. However, there are limited data regarding the influence of the flake size of BN sheets to the thermal management property of BN filled composites. In this work, three h-BN size geometries, including microscale h-BN powder, h-BN nanosheets, and a mixture of micro and nanoscale h-BN, were studied regarding its thermal transfer performance. The results show that h-BN nanosheets are able to achieve the highest in-plane thermal conductivity with loading from 0 - 5 wt% while for the through-plane thermal conductivity, all three geometries show similar thermal property when the filler loading less than 5 wt%. Through-plane thermal conductivity exhibits a sudden increase to 5.69 W m-1 K-1 at a loading of 5 wt%..
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| 25. |
- Liu, Ya, 1991, et al.
(författare)
-
Graphene based thermal management system for battery cooling in electric vehicles
- 2020
-
Ingår i: Proceedings - 2020 IEEE 8th Electronics System-Integration Technology Conference, ESTC 2020.
-
Konferensbidrag (refereegranskat)abstract
- In this work, a graphene assembled film integrated heat sink and water cooling technology was used to build an experimental set-up of a thermal management system to demonstrate the possibility to achieve efficient cooling of the propulsion battery in electric vehicles. The experimental results showed that the temperature decrease of a Li-ion battery module can reach 11°C and 9 °C under discharge rates as of 2C and 1C, respectively. The calculated thermal resistance of the graphene based cooling system is about 76% of a similar copper based cooling system. Surface modification was carried out on the graphene sheet to achieve a reliable bonding between the graphene sheet and the battery cell surface. This work provides a proof of concept of a new highly efficient approach for electric vehicle battery thermal management using the light-weight material graphene.
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| 26. |
- Liu, Ya, 1991, et al.
(författare)
-
Surface modification of graphene for use as a structural Fortifier in water-borne epoxy coatings
- 2019
-
Ingår i: Coatings. - : MDPI AG. - 2079-6412. ; 9:11
-
Tidskriftsartikel (refereegranskat)abstract
- Graphene, the typical two-dimensional sp2 hybridized carbon allotrope, is widely used as a filler for improving the mechanical performance of polymers. However, its superhydrophobic surface makes it a big challenge to obtain stable graphene dispersions, especially in water-borne systems. On the contrary, graphene oxide (GO) shows excellent dispersibility in water, but strong oxidants and acids destroy its structure and degrade its mechanical properties. This largely limits its application in water-borne coatings. In this work, graphene from mechanical exfoliation was surface modified by p-aminophenol derived diazonium salt to achieve a homogenous dispersion. Moreover, the hydroxyl groups in p-aminophenol are able to combine with epoxy resins during the curing process to improve mechanical performance of the final coatings. The result shows that functionalized graphene shows a lower coefficient of friction and better abrasion resistance compared to GO.
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| 27. |
- Liu, Ya, 1991, et al.
(författare)
-
Thermally Conductive and Electrically Insulating PVP/Boron Nitride Composite Films for Heat Spreader
- 2019
-
Ingår i: Proceedings - 2019 IMAPS Nordic Conference on Microelectronics Packaging, NORDPAC 2019. ; , s. 1-5
-
Konferensbidrag (refereegranskat)abstract
- Thermally conductive materials with electrically insulating properties have been extensively investigated for thermal management of electronic devices. The combined properties of high thermal conductivity, structural stability, corrosion resistance and electric resistivity make hexagonal boron nitride (h-BN) a promising candidate for this purpose. Theoretical studies have revealed that h-BN has a high in-plane thermal conductivity up to 400-800 W m-1 K-1 at room temperature. However, it is still a big challenge to achieve high thermally conductive h-BN thick films that are commercially feasible due to its poor mechanical properties. On the other hand, many polymers exhibit advantages for flexibility. Thus, combining the merits of polymer and the high thermal conductivity of h-BN particles is considered as a promising solution for this issue. In this work, orientated PVP/h-BN films were prepared by electrospinning and a subsequent mechanical pressing process. With the optimized h-BN loading, a PVP/h-BN composite film with up to 22 W m-1 K-1 and 0.485 W m-1 K-1 for in-plane and through-plane thermal conductivity can be achieved, respectively. We believe this work can help accelerate the development of h-BN for thermal management applications.
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| 28. |
- Liu, Ya, 1991, et al.
(författare)
-
Thermally Conductive and Electrically Insulating PVP/Boron Nitride Composite Films for Heat Spreader
- 2019
-
Ingår i: Advancing Microelectronics. - 2222-8748. ; 2019:NOR, s. 1-5
-
Tidskriftsartikel (refereegranskat)abstract
- Thermally conductive materials with electrically insulating properties have been extensively investigated for thermal management of electronic devices. The combined properties of high thermal conductivity, structural stability, corrosion resistance and electric resistivity make hexagonal boron nitride (h-BN) a promising candidate for this purpose. Theoretical studies have revealed that h-BN has a high in-plane thermal conductivity up to 400 - 800 W m−1 K−1 at room temperature. However, it is still a big challenge to achieve high thermally conductive h-BN thick films that are commercially feasible due to its poor mechanical properties. On the other hand, many polymers exhibit advantages for flexibility. Thus, combining the merits of polymer and the high thermal conductivity of h-BN particles is considered as a promising solution for this issue. In this work, orientated PVP/h-BN films were prepared by electrospinning and a subsequent mechanical pressing process. With the optimized h-BN loading, a PVP/h-BN composite film with up to 22 W m-1 K-1 and 0.485 W m-1 K-1 for in-plane and through-plane thermal conductivity can be achieved, respectively. We believe this work can help accelerate the development of h-BN for thermal management applications.
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| 29. |
- Piao, Shilong, et al.
(författare)
-
Evidence for a weakening relationship between interannual temperature variability and northern vegetation activity.
- 2014
-
Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 5
-
Tidskriftsartikel (refereegranskat)abstract
- Satellite-derived Normalized Difference Vegetation Index (NDVI), a proxy of vegetation productivity, is known to be correlated with temperature in northern ecosystems. This relationship, however, may change over time following alternations in other environmental factors. Here we show that above 30°N, the strength of the relationship between the interannual variability of growing season NDVI and temperature (partial correlation coefficient RNDVI-GT) declined substantially between 1982 and 2011. This decrease in RNDVI-GT is mainly observed in temperate and arctic ecosystems, and is also partly reproduced by process-based ecosystem model results. In the temperate ecosystem, the decrease in RNDVI-GT coincides with an increase in drought. In the arctic ecosystem, it may be related to a nonlinear response of photosynthesis to temperature, increase of hot extreme days and shrub expansion over grass-dominated tundra. Our results caution the use of results from interannual time scales to constrain the decadal response of plants to ongoing warming.
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| 30. |
- Sun, Yaoran, et al.
(författare)
-
Bendable, ultra-black absorber based on a graphite nanocone nanowire composite structure
- 2015
-
Ingår i: Optics Express. - : Optica Publishing Group. - 1094-4087. ; 23:15, s. 20115-20123
-
Tidskriftsartikel (refereegranskat)abstract
- A bendable ultra-black material consisting of graphite nanocones and nanowires is fabricated through a simple plasma etching process. The optical properties of the absorber are characterized in the wavelength range of 400-2000 nm with average specular reflectance 0.05 +/- 0.03% at normal incidence and the material thickness is only around 5 mu m. The reflectance of the absorber remains low at large incident angles and is relatively independent of polarization. Simulations confirm the cooperative effect of the nanowires and nanocones leading to an ultra-black thin carbon material.
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| 31. |
- Wang, Nan, et al.
(författare)
-
Highly thermal conductive and electrically insulated graphene based thermal interface material with long-term reliability
- 2019
-
Ingår i: Proceedings - Electronic Components and Technology Conference. - 0569-5503. ; 2019-May, s. 1564-1568
-
Konferensbidrag (refereegranskat)abstract
- High density packaging in combination with increased transistor integration inevitably leads to challenging power densities in terms of thermal management. The conventional TIMs that are widely used in the microelectronic industry today are experiencing more and more stress due to their limited thermal performance and poor reliability. Composed by particle laden polymer matrix, thermal conductivity (K) of conventional TIMs is generally limited to 5 W/mK, and such values can be even lower for electrically insulated TIMs. Conventional TIMs also suffer from severe pump-out and dry-out failures, which brought great threat to the performance and lifetime of the electronic devices. Here, we solve these problems by applying a novel highly thermal conductive, electrically insulated and reliable graphene based TIMs (I-GTs). Composed by vertical graphene structures, I-GTs provide a continuous heat pathway from top to bottom, which enables superfast heat dissipation at through-plane direction. The highest bulk through-plane thermal conductivity of the conductive body can reach up to 1000 W/mK, which is orders of magnitude higher than conventional TIMs, and even outperforms the pure indium TIMs by over ten times. The highly flexible and foldable nature of I-GT enables at least 100% compressibility upon small applied pressures. As excellent gap fillers, I-GT can provide complete physical contact between two surfaces and thereby minimize the contact resistance to heat flow. The measured minimum thermal resistance for I-GTs reaches about 30 Kmm2/W. Such values are significantly higher than the randomly dispersed composites presented above. To ensure fully electrical insulation, a smooth and soft adhesive layer with a thickness of few microns was coated on the surface of I-GT. The breakdown voltage of I-GT reaches up to 950 V. Thermal cycling test shows the highly stable nature of I-GT. The good compressibility and elasticity of I-GT ensures continued proper TIM contact with substrates, which counteracts the effect of internal stress induced by the mismatch of coefficient of thermal expansion (CTE) during temperature cycling. In addition, the I-GTs have the advantages of low density and good maintainability. The resulting I-GTs thus opens new opportunities for addressing large heat dissipation issues for form-factor driven electronics and other high power driven systems.
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| 32. |
- Wang, Nan, et al.
(författare)
-
Highly Thermal Conductive and Light -weight Craphene-based Heatsink
- 2019
-
Ingår i: 2019 22ND EUROPEAN MICROELECTRONICS AND PACKAGING CONFERENCE & EXHIBITION (EMPC). - 2165-2341. - 9780956808660
-
Konferensbidrag (refereegranskat)abstract
- With the developing trend ofminiaturization and integration of modem electronic devices, commercial hearsinks ivaterigh, like copper and ii iv are facing mare and mare challenges, such as inefficient cooling performance, large size turd heavy weight. Here, we salve the probletn by developing a novel highly thermal conductive and 11Mo-weight graphene heatsink. Cornposed by vertically-aligned and continUOUS graphene structures, heat transport was highly efficiero from the base 1o fin Ii: ininside the heatsink, The maximum through-platre thermal catuluctivity ofgraphene heatsink can be up to 1000 1500 Ward( which is over 7 times higher than aluminum, and even outperforms copper about 4 times_ Gmphene heatsink demonstrated outstanding cooling perffrmance which wm superior to copper heatsink with the same dimension and same power input. Noticeably, the graphene hearsink also has anportant advantagas of light-weight and high emissions,. The measured density (1 1 g cmli is only onroeighth of copper and lam than hoor of aluminum and emissivity is about ten times hiher than pure rapper and aluminum. The resulting graphene heatsink thus opertS rim opportunities for addressing large heat dissMatMn issues in weight' driven electronics and othm high power smions.
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| 33. |
- Ye, Chao, et al.
(författare)
-
Comprehensive understanding of Saccharomyces cerevisiae phenotypes with whole-cell model WM_S288C
- 2020
-
Ingår i: Biotechnology and Bioengineering. - : Wiley. - 0006-3592 .- 1097-0290. ; 117:5, s. 1562-1574
-
Tidskriftsartikel (refereegranskat)abstract
- Biological network construction for Saccharomyces cerevisiae is a widely used approach for simulating phenotypes and designing cell factories. However, due to a complicated regulatory mechanism governing the translation of genotype to phenotype, precise prediction of phenotypes remains challenging. Here, we present WM_S288C, a computational whole-cell model that includes 15 cellular states and 26 cellular processes and which enables integrated analyses of physiological functions of Saccharomyces cerevisiae. Using WM_S288C to predict phenotypes of S. cerevisiae, the functions of 1140 essential genes were characterized and linked to phenotypes at five levels. During the cell cycle, the dynamic allocation of intracellular molecules could be tracked in real-time to simulate cell activities. Additionally, one-third of non-essential genes were identified to affect cell growth via regulating nucleotide concentrations. These results demonstrated the value of WM_S288C as a tool for understanding and investigating the phenotypes of S. cerevisiae.
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| 34. |
- Ye, Xiaoling, et al.
(författare)
-
High Performance Self-Powered Photodetectors Based on Graphene Nanoribbons/Al2O3/InGaZnO Heterojunctions
- 2024
-
Ingår i: IEEE Photonics Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1943-0655. ; 16:3
-
Tidskriftsartikel (refereegranskat)abstract
- Self-powered photodetectors which operate without external power sources hold immense promise in future photodetection systems. To achieve high-performance self-powered optoelectronic devices, efficient electron-hole pair separation is critical to generate high photocurrents. In this work, we successfully synthesized semiconducting graphene nanoribbons (GNRs) with a direct bandgap of 1.80 eV and employed them to construct a high-performance GNR/Al2O3/IGZO heterostructure photodetector. The built-in electric field in the heterojunctions enables this photodetector to exhibit remarkable performance, showing a responsivity of up to 68 mA/W, a detectivity of 8.34 x 1010 Jones, and rapid response times of 21/20 ms at zero bias. Furthermore, the photodetector features a wide spectral detection range of 405 to 1550 nm. These results highlight the promising potential of GNR/IGZO p-n heterojunction-based self-powered photodetectors in optoelectronic applications.
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| 35. |
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| 36. |
- Zhang, Maomao, et al.
(författare)
-
Effect of pressure during graphitization on mechanical properties of graphene films
- 2019
-
Ingår i: 2019 20th International Conference on Electronic Packaging Technology, ICEPT 2019.
-
Konferensbidrag (refereegranskat)abstract
- Graphene films (GFs) can be used in the field of electronics cooling, owing to many outstanding properties. In the present paper, GFs samples were graphitized at different pressures to study their effect on the mechanical properties. The elastic modulus and hardness of GFs were measured by nanoindentation and the tensile strength of GFs were obtained by stretching GFs in a tensile tester. Meanwhile, GFs were characterized by X-ray diffraction(XRD), Scanning electron microscopy (SEM) and Raman spectroscopy. The results show that the modulus, hardness and tensile strength of GFs were strongly influenced by the defect and wrinkles among other things.
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| 37. |
- Zhang, Q., et al.
(författare)
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Effect of sintering method on properties of nanosilver paste
- 2017
-
Ingår i: 2017 IMAPS Nordic Conference on Microelectronics Packaging, NordPac 2017, Goteborg, Sweden, 18-20 June 2017. ; , s. 186-189
-
Konferensbidrag (refereegranskat)abstract
- Nanoscale silver paste has a good application prospect in heat dissipation of high-power chips due to the characteristics of low temperature sintering and high temperature service. The properties of the nanosilver paste including thermal conductivity, electrical conductivity, and shear strength are affected greatly by the sintering process. The influence of different sintering methods on the performance of the nanosilver paste was studied in this article. The nanosilver paste with 80.5 wt% nano-scale silver particles, 1.5 wt% submicron-scale SiC particles with Ag coating, 0.9 wt% dispersion agent, 10 wt% organic carrier and 7.1 wt% diluting agent was sintered at 260°C for 30 min with three different methods, heating table sintering, heating furnace sintering, and mixed sintering. The samples obtained by mixed sintering process have higher thermal conductivity than the ones obtained by heating furnace sintering method and heating table sintering method. The effect of sintering methods on shear strength of nanosilver paste was also investigated subsequently. Shear testing equipment was used to measure the shear strength of the samples gained by heating table sintering, heating furnace sintering, and air dry oven sintering. The maximum shear strength was obtained for the samples by heating table sintering method. The shear strength of samples by air dry oven sintering method was the minimum one.
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| 38. |
- Zhang, Q., et al.
(författare)
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Mechanical property and reliability of bimodal nano-silver paste with Ag-coated SiC particles
- 2019
-
Ingår i: Soldering and Surface Mount Technology. - 1758-6836 .- 0954-0911. ; 31:4, s. 193-202
-
Tidskriftsartikel (refereegranskat)abstract
- © 2019, Emerald Publishing Limited. Purpose: This study aims to develop a bimodal nano-silver paste with improved mechanical property and reliability. Silicon carbide (SiC) particles coated with Ag were introduced in nano-silver paste to improve bonding strength between SiC and Ag particles and enhance high-temperature stability of bimodal nano-silver paste. The effect of sintering parameters such as sintering temperature, sintering time and the proportion of SiC particles on mechanical property and reliability of sintered bimodal nano-silver structure were investigated. Design/methodology/approach: Sandwich structures consist of dummy chips and copper substrates with nickel and silver coating bonded by nano-silver paste were designed for shear testing. Shear strength testing was conducted to study the influence of SiC particles proportions on the mechanical property of sintered nano-silver joints. The reliability of the bimodal nano-silver paste was evaluated experimentally by means of shear test for samples subjected to thermal aging test at 150°C and humidity and temperature testing at 85°C and 85 per cent RH, respectively. Findings: Shear strength was enhanced obviously with the increase of sintering temperature and sintering time. The maximum shear strength was achieved for nano-silver paste sintered at 260°C for 10 min. There was a negative correlation between the proportion of SiC particles and shear strength. After thermal aging testing and humidity and temperature testing for 240 h, the shear strength decreased a little. High-temperature stability and high-hydrothermal stability were improved by the addition of SiC particles. Originality/value: Submicron-scale SiC particles coated with Ag were used as alternative materials to replace part of nano-silver particles to prepare bimodal nano-silver paste due to its high thermal conductivity and excellent mechanical property.
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| 39. |
- Zhao, Changhong, 1982, et al.
(författare)
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Synthesis of graphene quantum dots and their applications in drug delivery
- 2020
-
Ingår i: Journal of Nanobiotechnology. - : Springer Science and Business Media LLC. - 1477-3155. ; 18:1
-
Forskningsöversikt (refereegranskat)abstract
- This review focuses on the recent advances in the synthesis of graphene quantum dots (GQDs) and their applications in drug delivery. To give a brief understanding about the preparation of GQDs, recent advances in methods of GQDs synthesis are first presented. Afterwards, various drug delivery-release modes of GQDs-based drug delivery systems such as EPR-pH delivery-release mode, ligand-pH delivery-release mode, EPR-Photothermal delivery-Release mode, and Core/Shell-photothermal/magnetic thermal delivery-release mode are reviewed. Finally, the current challenges and the prospective application of GQDs in drug delivery are discussed.[Figure not available: see fulltext.]
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| 40. |
- Zhao, Sen, et al.
(författare)
-
Expanding the mutation and phenotype spectrum of MYH3-associated skeletal disorders
- 2022
-
Ingår i: NPJ genomic medicine. - : Nature Publishing Group. - 2056-7944. ; 7:1
-
Tidskriftsartikel (refereegranskat)abstract
- Pathogenic variants in MYH3 cause distal arthrogryposis type 2A and type 2B3 as well as contractures, pterygia and spondylocarpotarsal fusion syndromes types 1A and 1B. These disorders are ultra-rare and their natural course and phenotypic variability are not well described. In this study, we summarize the clinical features and genetic findings of 17 patients from 10 unrelated families with vertebral malformations caused by dominant or recessive pathogenic variants in MYH3. Twelve novel pathogenic variants in MYH3 (NM_002470.4) were identified: three of them were de novo or inherited in autosomal dominant way and nine were inherited in autosomal recessive way. The patients had vertebral segmentation anomalies accompanied with variable joint contractures, short stature and dysmorphic facial features. There was a significant phenotypic overlap between dominant and recessive MYH3-associated conditions regarding the degree of short stature as well as the number of vertebral fusions. All monoallelic variants caused significantly decreased SMAD3 phosphorylation, which is consistent with the previously proposed pathogenic mechanism of impaired canonical TGF-β signaling. Most of the biallelic variants were predicted to be protein-truncating, while one missense variant c.4244T>G,p.(Leu1415Arg), which was inherited in an autosomal recessive way, was found to alter the phosphorylation level of p38, suggesting an inhibition of the non-canonical pathway of TGF-β signaling. In conclusion, the identification of 12 novel pathogenic variants and overlapping phenotypes in 17 affected individuals from 10 unrelated families expands the mutation and phenotype spectrum of MYH3-associated skeletal disorders. We show that disturbances of canonical or non-canonical TGF-β signaling pathways are involved in pathogenesis of MYH3-associated skeletal fusion (MASF) syndrome.
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| 41. |
- Zhao, Xiaoming, et al.
(författare)
-
Accelerated aging of all-inorganic, interface-stabilized perovskite solar cells
- 2022
-
Ingår i: Science. - : AMER ASSOC ADVANCEMENT SCIENCE. - 0036-8075 .- 1095-9203. ; 377:6603, s. 307-310
-
Tidskriftsartikel (refereegranskat)abstract
- To understand degradation routes and improve the stability of perovskite solar cells (PSCs), accelerated aging tests are needed. Here, we use elevated temperatures (up to 110 degrees C) to quantify the accelerated degradation of encapsulated CsPbI3 PSCs under constant illumination. Incorporating a two-dimensional (2D) Cs2PbI2Cl2 capping layer between the perovskite active layer and hole-transport layer stabilizes the interface while increasing power conversion efficiency of the all-inorganic PSCs from 14.9 to 17.4%. Devices with this 2D capping layer did not degrade at 35 degrees C and required >= 2100 hours at 110 degrees C under constant illumination to degrade by 20% of their initial efficiency. Degradation acceleration factors based on the observed Arrhenius temperature dependence predict intrinsic lifetimes of 51,000 +/- 7000 hours (>5 years) operating continuously at 35 degrees C.
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| 42. |
- Zhu, Jialin, et al.
(författare)
-
Asymmetric cross rolling : A new technique for alleviating orientation-dependent microstructure inhomogeneity in tantalum sheets
- 2020
-
Ingår i: Journal of Materials Research and Technology. - : Elsevier BV. - 2238-7854. ; 9:3, s. 4566-4577
-
Tidskriftsartikel (refereegranskat)abstract
- New rolling technique, i.e. asymmetric rolling combined with cross rolling is adopted to produce Ta sputtering targets in this study. Electron backscatter diffraction (EBSD) analysis suggests that (111) and (100) deformed grains distribute alternately along normal direction in cross rolling (CR) and asymmetric cross rolling (ACR) samples. Misorientation angle distribution indicates that severe orientation-dependent grain fragmentation exists in the CR sample, which is also confirmed by kernel average misorientation and grain reference orientation deviation-hyper. Grain average misorientation (GAM) and distribution of geometrically necessary dislocations (GNDs) suggest that the effect of increasing shear strain introduced by asymmetric rolling on deformation microstructure is mainly reflected in the (100) grains, which is further verified by orientation-dependent microhardness values. The computation of Schmid factor indicates that slip within (100) grains in the ACR sample is easier, and the system with higher Schmid factor can alone accommodate the majority of plastic strain. Transmission electron microscopy (TEM) reveals that dense dislocation walls (DDWs) are formed within the (100) deformed grains in the ACR sample, while only sparse dislocation lines can be observed in the CR sample. X-ray line profile analysis (XLPA) displays that ACR can significantly increase the stored energy of the (100) deformed grains and thus weaken the orientation-dependent stored energy distribution. The enhanced recrystallization ability of the (100) grains in the ACR sample facilitates homogenization of the annealing microstructure.
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| 43. |
- Thomas, HS, et al.
(författare)
-
- 2019
-
swepub:Mat__t
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| 44. |
- Anderson, Cynthia M., et al.
(författare)
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Permanent Genetic Resources added to Molecular Ecology Resources Database 1 December 2009-31 January 2010
- 2010
-
Ingår i: Molecular Ecology Resources. - : Wiley. - 1755-098X .- 1755-0998. ; 10:3, s. 576-579
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Tidskriftsartikel (refereegranskat)abstract
- This article documents the addition of 220 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Allanblackia floribunda, Amblyraja radiata, Bactrocera cucurbitae, Brachycaudus helichrysi, Calopogonium mucunoides, Dissodactylus primitivus, Elodea canadensis, Ephydatia fluviatilis, Galapaganus howdenae howdenae, Hoplostethus atlanticus, Ischnura elegans, Larimichthys polyactis, Opheodrys vernalis, Pelteobagrus fulvidraco, Phragmidium violaceum, Pistacia vera, and Thunnus thynnus. These loci were cross-tested on the following species: Allanblackia gabonensis, Allanblackia stanerana, Neoceratitis cyanescens, Dacus ciliatus, Dacus demmerezi, Bactrocera zonata, Ceratitis capitata, Ceratitis rosa, Ceratits catoirii, Dacus punctatifrons, Ephydatia mulleri, Spongilla lacustris, Geodia cydonium, Axinella sp., Ischnura graellsii, Ischnura ramburii, Ischnura pumilio, Pistacia integerrima and Pistacia terebinthus.
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| 45. |
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| 46. |
- Birney, Ewan, et al.
(författare)
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Identification and analysis of functional elements in 1% of the human genome by the ENCODE pilot project
- 2007
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 447:7146, s. 799-816
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Tidskriftsartikel (refereegranskat)abstract
- We report the generation and analysis of functional data from multiple, diverse experiments performed on a targeted 1% of the human genome as part of the pilot phase of the ENCODE Project. These data have been further integrated and augmented by a number of evolutionary and computational analyses. Together, our results advance the collective knowledge about human genome function in several major areas. First, our studies provide convincing evidence that the genome is pervasively transcribed, such that the majority of its bases can be found in primary transcripts, including non-protein-coding transcripts, and those that extensively overlap one another. Second, systematic examination of transcriptional regulation has yielded new understanding about transcription start sites, including their relationship to specific regulatory sequences and features of chromatin accessibility and histone modification. Third, a more sophisticated view of chromatin structure has emerged, including its inter-relationship with DNA replication and transcriptional regulation. Finally, integration of these new sources of information, in particular with respect to mammalian evolution based on inter- and intra-species sequence comparisons, has yielded new mechanistic and evolutionary insights concerning the functional landscape of the human genome. Together, these studies are defining a path for pursuit of a more comprehensive characterization of human genome function.
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| 47. |
- Casa, Marcello, et al.
(författare)
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Development and characterization of graphene-enhanced thermal conductive adhesives
- 2014
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Ingår i: 15th International Conference on Electronic Packaging Technology, ICEPT 2014; Wangjiang HotelChengdu; China; 12 August 2014 through 15 August 2014. - 9781479947072 ; :Art. no. 6922700, s. 480-483
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Konferensbidrag (refereegranskat)abstract
- According to Moore's Laws, complexity and power densities of electronic devices are increased during the last decades, moreover their dimensions are shrinking to nanometers causing hot-spot temperature escalation. Thermal management, therefore, becomes a critical issue for next generation of electronics. This scenario motivates development of novel thermal conductive adhesive (TCA) with enhanced thermal conductivity. Conventional TCAs use polymers as the matrix (base material) and utilize large loading weight fraction of the filler, usually silver particles, to achieve the thermal conductivity of 1-4 W/ m K at room temperature [1]. Lately it was discovered that graphene exhibit superior thermal conductivity [2] even when they are incorporated with matrix materials [3], which offers a potential to develop high thermal conductive graphene-filled compound. In this paper, a new functionalized graphene and its filled TCA have been developed and characterized. Starting from pristine graphite flakes, graphene was prepared through chemical exfoliation and functionalized with a nano silver layer to form a special metal/graphene hybrid material. Moreover, an efficient method to uniformly disperse the nano-scaled graphene hybrid material in silver-epoxy matrix was developed. Cross-section view of SEM has shown a homogeneous component structure, and TGA analysis of hybrid material is given. The developed compound is based on a commercial TCA which is composed with epoxy matrix and micro-sized Ag flakes. Thermal characterization through Laser-flash equipment has indicated that a significant thermal conductivity improvement was achieved through adding functionalized graphene into the material. Different TCA samples with different weight percentages of functionalized graphene ranging from 0 % (reference) to 11.5 % were prepared and tested to study thermal conductivity change. Data show that a thermal conductivity value of 7.6 W/ m K is reached when the graphene/silver percentage is 11.5 % that is almost 4 times higher than our reference.
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| 48. |
- Chen, Gang, et al.
(författare)
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Utilization-Based Scheduling of Flexible Mixed-Criticality Real-Time Tasks
- 2018
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Ingår i: IEEE Transactions on Computers. - : IEEE COMPUTER SOC. - 0018-9340 .- 1557-9956. ; 67:4, s. 543-558
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Tidskriftsartikel (refereegranskat)abstract
- Mixed-criticality models are an emerging paradigm for the design of real-time systems because of their significantly improved resource efficiency. However, formal mixed-criticality models have traditionally been characterized by two impractical assumptions: once any high-criticality task overruns, all low-criticality tasks are suspended and all other high-criticality tasks are assumed to exhibit high-criticality behaviors at the same time. In this paper, we propose a more realistic mixed-criticality model, called the flexible mixed-criticality (FMC) model, in which these two issues are addressed in a combined manner. In this new model, only the overrun task itself is assumed to exhibit high-criticality behavior, while other high-criticality tasks remain in the same mode as before. The guaranteed service levels of low-criticality tasks are gracefully degraded with the overruns of high-criticality tasks. We derive a utilization-based technique to analyze the schedulability of this new mixed-criticality model under EDF-VD scheduling. During run time, the proposed test condition serves an important criterion for dynamic service level tuning, by means of which the maximum available execution budget for low-criticality tasks can be directly determined with minimal overhead while guaranteeing mixed-criticality schedulability. Experiments demonstrate the effectiveness of the FMC scheme compared with state-of-the-art techniques.
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| 49. |
- Chen, Hong, et al.
(författare)
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Building a Measurement Model for Port-Hinterland Container Transportation Network Resilience
- 2015
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Ingår i: LOGMS International Conference on Logistics and Maritime Systems. Hong Kong University of Science & Technology, Hong Kong, 27-29 August..
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Konferensbidrag (refereegranskat)abstract
- The ongoing development of world trade has bolstered the demand for container transport that is both safe and resilient. As a pivotal element in international logistics and economic development at both national and local levels, container transportation between seaports and their associated hinterlands is critically important. In this paper, we apply the concept of resilience to the context of a port-hinterland container transportation network. The concept of resilience incorporates issues relating to both safety and risk management, but possesses its own distinctive characteristics which differentiates it from other concepts, such as stability and robustness. We firstly propose our definition of resilience within this context, based upon a comprehensive review of the relevant literature. Next, a stochastic integer programming model is built to yield a quantitative measure of resilience from the perspective of shippers. This measurement model is then tested by developing a numerical simulation based on the specific case of Gothenburg port and part of its hinterland. By analysing the resilience concept in general and the specific results from the numerical simulation, we then evaluate the validity and reliability of our contextual definition of resilience and the measurement model developed. We find them to be not only theoretically meaningful, but also practically useful.
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| 50. |
- Chen, Hanwei, et al.
(författare)
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Tumor Volumes Measured From Static and Dynamic F-18-fluoro-2-deoxy-D-glucose Positron Emission Tomography-Computed Tomography Scan : Comparison of Different Methods Using Magnetic Resonance Imaging as the Criterion Standard
- 2014
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Ingår i: Journal of computer assisted tomography. - 0363-8715 .- 1532-3145. ; 38:2, s. 209-215
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The objective of this study was to compare the accuracy of calculating the primary tumor volumes using a gradient-based method and fixed threshold methods on the standardized uptake value (SUV) maps and the net influx of FDG (Ki) maps from positron emission tomography-computed tomography (PET-CT) images. Materials and Methods: Newly diagnosed patients with head and neck cancer were recruited, and dynamic PET-CT scan and T2-weighted magnetic resonance imaging were performed. The maps of Ki and SUV were calculated from PET-CT images. The tumor volumes were calculated using a gradient-based method and a fixed threshold method at 40% of maximal SUV or maximal Ki. Four kinds of volumes, VOLKi-Gra (from the Ki maps using the gradient-based method), VOLKi-40% (from the Ki maps using the threshold of 40% maximal Ki), VOLSUV-Gra (from the SUV maps using the gradient-based method), and VOLSUV-40% (from the SUV maps using the threshold of 40% maximal SUV), were acquired and compared with VOLMRI (the volumes acquired on T2-weighted images) using the Pearson correlation, paired t test, and similarity analysis. Results: Eighteen patients were studied, of which 4 had poorly defined tumors (PDT). The positron emission tomography-derived volumes were as follows: VOLSUV-40%, 2.1 to 41.2 cm(3) (mean [SD], 12.3 [10.6]); VOLSUV-Gra, 2.2 to 28.1 cm(3) (mean [SD], 13.2 [8.4]); VOLKi-Gra, 2.4 to 17.0 cm(3) (mean [SD], 9.5 [4.6]); and VOLKi-40%, 2.7 to 20.3 cm(3) (mean [SD], 12.0 [6.0]). The VOLMRI ranged from 2.9 to 18.1 cm(3) (mean [SD], 9.1 [3.9]). The VOLKi-Gra significantly correlated with VOLMRI with the highest correlation coefficient (PDT included, R = 0.673, P = 0.002; PDT excluded, R = 0.841, P < 0.001) and presented no difference from VOLMRI (P = 0.672 or 0.561, respectively, PDT included and excluded). The difference between VOLKi-Gra and VOLMRI was also the smallest. Conclusions: The tumor volumes delineated on the Ki maps using the gradient-based method are more accurate than those on the SUV maps and using the fixed threshold methods.
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