| 1. |
- Campbell, PJ, et al.
(author)
-
Pan-cancer analysis of whole genomes
- 2020
-
In: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 578:7793, s. 82-
-
Journal article (peer-reviewed)abstract
- Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale1–3. Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4–5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter4; identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation5,6; analyses timings and patterns of tumour evolution7; describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity8,9; and evaluates a range of more-specialized features of cancer genomes8,10–18.
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
- Kanai, M, et al.
(author)
-
- 2023
-
swepub:Mat__t
|
|
| 6. |
- Yao, S. T., et al.
(author)
-
Waves in Kinetic-Scale Magnetic Dips : MMS Observations in the Magnetosheath
- 2019
-
In: Geophysical Research Letters. - : AMER GEOPHYSICAL UNION. - 0094-8276 .- 1944-8007. ; 46:2, s. 523-533
-
Journal article (peer-reviewed)abstract
- Kinetic scale magnetic dips (KSMDs), with a significant depression in magnetic field strength, and scale length close to and less than one proton gyroradius, were reported in the turbulent plasmas both in recent observation and numerical simulation studies. These KSMDs likely play important roles in energy conversion and dissipation. In this study, we present observations of the KSMDs that are labeled whistler mode waves, electrostatic solitary waves, and electron cyclotron waves in the magnetosheath. The observations suggest that electron temperature anisotropy or beams within KSMD structures provide free energy to generate these waves. In addition, the occurrence rates of the waves are higher in the center of the magnetic dips than at their edges, implying that the KSMDs might be the origin of various kinds of waves. We suggest that the KSMDs could provide favorable conditions for the generation of waves and transfer energy to the waves in turbulent magnetosheath plasmas. Plain Language Summary The Earth's magnetosheath is a turbulent plasma environment where energy conversion, particle acceleration, and mass and momentum transport take place. Many of these key processes involve kinetic-scale physics. However, in-depth studies from previous missions are limited by their lower spacecraft data resolution. The recent Magnetospheric Multiscale (MMS) mission provides us with a large amount of high-temporal cadence data for studying kinetic-scale physics in the magnetosheath. In this study, we report whistler mode waves, electrostatic solitary waves and electron cyclotron waves within kinetic-scale magnetic dips (KSMDs) that can be generated in the turbulent magnetosheath. These waves could be excited by electron temperature anisotropy or beams. As is well known, plasma waves are important processes in converting energy, accelerating and scattering electrons and ions, and modifying the distributions of charged particles. If plasma instabilities develop within the KSMDs, the resulting waves could absorb free energy from plasma particles and may propagate out of the KSMDs. Thus, our discoveries could significantly advance the understanding of energy conversion and dissipation for kinetic-scale turbulence. This study provides a new reference not only for observations in space physics but also for related basic plasma theories and numerical simulations.
|
|
| 7. |
- Abgrall, N., et al.
(author)
-
The large enriched germanium experiment for neutrinoless double beta decay (LEGEND)
- 2017
-
In: AIP Conference Proceedings. - : Author(s). - 1551-7616 .- 0094-243X. ; 1894
-
Conference paper (peer-reviewed)abstract
- The observation of neutrinoless double-beta decay (0νββ) would show that lepton number is violated, reveal that neu-trinos are Majorana particles, and provide information on neutrino mass. A discovery-capable experiment covering the inverted ordering region, with effective Majorana neutrino masses of 15 - 50 meV, will require a tonne-scale experiment with excellent energy resolution and extremely low backgrounds, at the level of ∼0.1 count /(FWHM·t·yr) in the region of the signal. The current generation 76Ge experiments GERDA and the Majorana Demonstrator, utilizing high purity Germanium detectors with an intrinsic energy resolution of 0.12%, have achieved the lowest backgrounds by over an order of magnitude in the 0νββ signal region of all 0νββ experiments. Building on this success, the LEGEND collaboration has been formed to pursue a tonne-scale 76Ge experiment. The collaboration aims to develop a phased 0νββ experimental program with discovery potential at a half-life approaching or at 1028 years, using existing resources as appropriate to expedite physics results.
|
|
| 8. |
- Wu, X. C., et al.
(author)
-
CPSDv0: a forest stand structure database for plantation forests in China
- 2023
-
In: Big Earth Data. - : Informa UK Limited. - 2096-4471 .- 2574-5417. ; 7:1, s. 212-230
-
Journal article (peer-reviewed)abstract
- Forest stand structure is not only a crucial factor for regulating forest functioning but also an important indicator for sustainable forest management and ecosystem services. Although there exists a few national/global structure databases for natural forests, a country-wide synthetic structure database for plantation forests over China, the world's largest player in plantation forests, has not been achieved. In this study, we built a country-wide synthetic stand structure database by surveying more than 600 peer-reviewed literature. The database covers tree species, mean stand age, mean tree height, stand density, canopy coverage, diameter at breast height, as well as the associated ancillary in-situ topographical and soil properties. A total of 594 published studies concerning diverse forest stand structure parameters were compiled for 46 tree species. This first synthesis for stand structure of plantation forests over China supports studies on the evolution/ health of plantation forests in response to rapid climate change and intensified disturbances, and benefits country-wide sustainable forest management, future afforestation or reforestation planning. Potential users include those studying forest community dynamics, regional tree growth, ecosystem stability, and health, as well as those working with conservation and sustainable management.
|
|
| 9. |
- Zhang, Shi-Li, et al.
(author)
-
Abnormal anti-Stokes Raman scattering of carbon nanotubes
- 2002
-
In: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 66:3
-
Journal article (peer-reviewed)abstract
- Abnormal anti-Stokes Raman scattering (AASR) was unambiguously observed in carbon nanotubes (CNT's). In contrast to traditional Raman scattering theory, the absolute value of the Raman frequency of the anti-Stokes peak is not the same as that of the corresponding Stokes peak. It was demonstrated that AASR scattering originates from the unique nanoscale cylindrical structure of CNT's that can be considered naturally as a graphite structure with an intrinsic defect from its rolling. The double-resonance Raman scattering theory was applied to interpret the scattering mechanism of the AASR phenomenon successfully and quantitatively.
|
|
| 10. |
- Cossarizza, A., et al.
(author)
-
Guidelines for the use of flow cytometry and cell sorting in immunological studies (second edition)
- 2019
-
In: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 49:10, s. 1457-1973
-
Journal article (peer-reviewed)abstract
- These guidelines are a consensus work of a considerable number of members of the immunology and flow cytometry community. They provide the theory and key practical aspects of flow cytometry enabling immunologists to avoid the common errors that often undermine immunological data. Notably, there are comprehensive sections of all major immune cell types with helpful Tables detailing phenotypes in murine and human cells. The latest flow cytometry techniques and applications are also described, featuring examples of the data that can be generated and, importantly, how the data can be analysed. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid, all written and peer-reviewed by leading experts in the field, making this an essential research companion.
|
|
| 11. |
- Dagenais, G. R., et al.
(author)
-
Variations in Diabetes Prevalence in Low-, Middle-, and High-Income Countries: Results From the Prospective Urban and Rural Epidemiological Study
- 2016
-
In: Diabetes Care. - : American Diabetes Association. - 0149-5992 .- 1935-5548. ; 39:5, s. 780-787
-
Journal article (peer-reviewed)abstract
- OBJECTIVE The goal of this study was to assess whether diabetes prevalence varies by countries at different economic levels and whether this can be explained by known risk factors. The prevalence of diabetes, defined as self-reported or fasting glycemia >= 7 mmol/L, was documented in 119,666 adults from three high-income (HIC), seven upper-middle-income (UMIC), four lower-middle-income (LMIC), and four low-income (LIC) countries. Relationships between diabetes and its risk factors within these country groupings were assessed using multivariable analyses. Age- and sex-adjusted diabetes prevalences were highest in the poorer countries and lowest in the wealthiest countries (LIC 12.3%, UMIC 11.1%, LMIC 8.7%, and HIC 6.6%; P < 0.0001). In the overall population, diabetes risk was higher with a 5-year increase in age (odds ratio 1.29 [95% CI 1.28-1.31]), male sex (1.19 [1.13-1.25]), urban residency (1.24 [1.11-1.38]), low versus high education level (1.10 [1.02-1.19]), low versus high physical activity (1.28 [1.20-1.38]), family history of diabetes (3.15 [3.00-3.31]), higherwaist-to-hip ratio (highest vs. lowest quartile; 3.63 [3.33-3.96]), and BMI (>= 35 vs. < 25 kg/m(2); 2.76 [2.52-3.03]). The relationship between diabetes prevalence and both BMI and family history of diabetes differed in higher-versus lower-income country groups (P for interaction < 0.0001). After adjustment for all risk factors and ethnicity, diabetes prevalences continued to show a gradient (LIC 14.0%, LMIC 10.1%, UMIC 10.9%, and HIC 5.6%). Conventional risk factors do not fully account for the higher prevalence of diabetes in LIC countries. These findings suggest that other factors are responsible for the higher prevalence of diabetes in LIC countries.
|
|
| 12. |
|
|
| 13. |
- Klionsky, Daniel J., et al.
(author)
-
Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
-
In: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
-
Research review (peer-reviewed)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
|
|
| 14. |
- Liu, X., et al.
(author)
-
Intelligent Management and Control Technology of Cutting Tool Life-cycle for Intelligent Manufacturing
- 2021
-
In: Jixie Gongcheng Xuebao/Journal of Mechanical Engineering. - : Chinese Mechanical Engineering Society. - 0577-6686. ; 57:10, s. 196-219
-
Journal article (peer-reviewed)abstract
- Intelligent manufacturing is the main direction of the future manufacturing industry, the high-end manufacturing equipments represented by aerospace and automobile fields are related to national defense security and national economic lifeline. The higher requirements for the management and control of cutting tools are put forward by complex and diversified machining of parts. As the most active and state-changing element in the cutting process, the performance of the tool directly affects the machining accuracy and productivity. The advent of the big data era has led to a change in the tool management paradigm, with manufacturers, suppliers and application companies demanding life-cycle data on tools. By analyzing the current situation of tool management and control, the design and manufacturing precision, the accuracy of life prediction and scientific tool management and control are issues that need to be addressed. The connotation and key technologies of the whole life-cycle intelligent management and control of tools are proposed, the research results of domestic and foreign scholars in tool design and manufacturing intelligent optimisation, tool cutting process condition monitoring and tool multi-source data management sharing are reviewed, and finally the future research directions are prospected in the light of the application of tool control technology. With the continuous deepening of intelligent manufacturing, the intelligent management and control of cutting tool life-cycle based on artificial intelligence, big data, digital twin, cloud computing and other modern information technology will certainly promote the transformation and upgrading of tool industry chain.
|
|
| 15. |
- Liu, X., et al.
(author)
-
Surface roughness prediction method of titanium alloy milling based on CDH platform
- 2022
-
In: The International Journal of Advanced Manufacturing Technology. - : Springer Nature. - 0268-3768 .- 1433-3015. ; 119:11-12, s. 7145-7157
-
Journal article (peer-reviewed)abstract
- Generally, off-line methods are used for surface roughness prediction of titanium alloy milling. However, studies show that these methods have poor prediction accuracy. In order to resolve this shortcoming, a prediction method based on Cloudera’s Distribution including Apache Hadoop (CDH) platform is proposed in the present study. In this regard, data analysis and process platform are designed based on the CDH, which can upload, calculate, and store data in real time. Then this platform is combined with the Harris hawk optimization (HHO) algorithm and pattern search strategy, and an improved Harris hawk optimization optimization (IHHO) method is proposed accordingly. Then this method is applied to optimize the support vector machine (SVM) algorithm and predict the surface roughness in the CDH platform. The obtained results show that the prediction accuracy of IHHO method reaches 95%, which is higher than the conventional methods of SVM, BAT-SVM, gray wolf optimizer (GWO-SVM), and whale optimization algorithm (WOA-SVM).
|
|
| 16. |
- Wang, Z. B., et al.
(author)
-
Characteristics of regional new particle formation in urban and regional background environments in the North China Plain
- 2013
-
In: Atmos. Chem. Phys.. - : Copernicus Publications. - 1680-7324. ; 13:24, s. 12495-12506
-
Journal article (peer-reviewed)abstract
- Long-term measurements of particle number size distributions were carried out both at an urban background site (Peking University, PKU) and a regional Global Atmospheric Watch station (Shangdianzi, SDZ) from March to November in 2008. In total, 52 new particle formation (NPF) events were observed simultaneously at both sites, indicating that this is a regional phenomenon in the North China Plain. On average, the mean condensation sink value before the nucleation events started was 0.025 s−1 in the urban environment, which was 1.6 times higher than that at regional site. However, higher particle formation and growth rates were observed at PKU (10.8 cm−3 s−1 and 5.2 nm h−1) compared with those at SDZ (4.9 cm−3 s−1 and 4.0 nm h−1). These results implied that precursors were much more abundant in the polluted urban environment. Different from the observations in cleaner environments, the background conditions of the observed particle homogeneous nucleation events in the North China Plain could be characterized as the co-existing of a stronger source of precursor gases and a higher condensational sink of pre-existing aerosol particles. Secondary aerosol formation following nucleation events results in an increase of particle mass concentration, particle light scattering coefficient, and cloud condensation nuclei (CCN) number concentration, with consequences on visibility, radiative effects, and air quality. Typical regional NPF events with significant particle nucleation rates and subsequent particle growth over a sufficiently long time period at both sites were chosen to investigate the influence of NPF on the number concentration of "potential" CCN. As a result, the NPF and the subsequent condensable growth increased the CCN number concentration in the North China Plain by factors in the range from 5.6 to 8.7. Moreover, the potential contribution of anthropogenic emissions to the CCN number concentration was more than 50%, to which more attention should be drawn in regional and global climate modeling, especially in the polluted urban areas.
|
|
| 17. |
- Wei, X., et al.
(author)
-
Research on parallel distributed clustering algorithm applied to cutting parameter optimization
- 2022
-
In: The International Journal of Advanced Manufacturing Technology. - : Springer Nature. - 0268-3768 .- 1433-3015. ; 120:11-12, s. 7895-7904
-
Journal article (peer-reviewed)abstract
- In the big data era, traditional data mining technology cannot meet the requirements of massive data processing with the background of intelligent manufacturing. Aiming at insufficient computing power and low efficiency in mining process, this paper proposes a improved K-means clustering algorithm based on the concept of distributed clustering in cloud computing environment. The improved algorithm (T.K-means) is combined with MapReduce computing framework of Hadoop platform to realize parallel computing, so as to perform processing tasks of massive data. In order to verify the practical performance of T.K-means algorithm, taking machining data of milling Ti-6Al-4V alloy as the mining object. The mapping relationship among cutting parameters, surface roughness, and material removal rate is mined, and the optimized value for cutting parameters is obtained. The results show that T.K-means algorithm can be used to mine the optimal cutting parameters, so that the best surface roughness can be obtained in milling Ti-6Al-4V titanium alloy.
|
|
| 18. |
- Yu, X., et al.
(author)
-
Dynamic evolution and driving force analysis of land use/cover change on loess plateau watershed
- 2009
-
In: Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering. - 1002-6819. ; 25:7, s. 219-225
-
Journal article (peer-reviewed)abstract
- Using land resources quantity change model and land use/cover change index, dynamic changes and driving forces of land use/cover change were discussed in Tianshui, Gansu Province during the resent twenty years. The results showed that slope farmland area declined sharply, terrace area increased rapidly, forestland area and orchard area increased steadily from 1986 to 2004. According to the change of land-use type transfer, the entering speed of terrace was slightly less than the exiting speed, which was in a state of equilibrium for two-way high-speed conversion, while the entering speed of shrub land was less than the exiting speed, and presented a scale reduced trend. The change degrees of the land use types in the previous period (1986-1995) was much more obvious than that in the later period (1995-2004). Besides special topography and climate factors, national policies, population growth and economic development are driving forces of land use types change. After the implementation of the natural forest protection project and returning farmland to forest projects, land use situation in the region has been improved.
|
|
| 19. |
- Yue, C., et al.
(author)
-
Analytical Modeling of Tool Rake Wear in Titanium Alloy Milling Process
- 2021
-
In: Jixie Gongcheng Xuebao/Journal of Mechanical Engineering. - : Chinese Journal of Mechanical Engineering. - 0577-6686. ; 57:23, s. 232-240
-
Journal article (peer-reviewed)abstract
- Titanium alloy Ti6Al4V is a typical aerospace difficult-to-machine material. In the milling process, the wear of cemented carbide tools will reduce the stability of the machining process, thereby affecting the machining efficiency and the surface quality of the machined surface. The tool rake face wear will lead to the decrease of tool edge strength, and affect the flow direction and fracture of chip. The wear mechanism of rake face is analyzed and the prediction model of wear depth of crater groove is constructed. Firstly, the stress field model of the rake face is constructed by using the analytical method, and the stress distribution and wear location of the rake face of the milling tool during the sliding of the chip on rake face are obtained. Based on the contact relationship between tool and chip, the temperature field model of rake face is established. Then, based on the stress and temperature distribution on the rake face of the tool, a prediction model of the crater wear depth of the milling tool considering the abrasion wear, adhesion wear and diffusion wear is constructed, and the prediction curve of the crater wear is obtained. Combined with the distribution characteristics of the crater wear zone along the cutting edge direction of the milling tool, the wear volume prediction model of the milling tool rake face with time variation is established. Finally, the influence of cutting width on rake face wear is verified by experiments, and the predicted results are in good agreement with the experimental measurements. The results show that with the increase of cutting width, the wear depth and the wear volume of rake face also increase. The results of this study provide a theoretical basis for the design of milling tools and the reasonable selection of cutting parameters for titanium alloy milling.
|
|
| 20. |
- Yue, C., et al.
(author)
-
Wear behavior of tool flank in the side milling of Ti6Al4V : An analytical model and experimental validation
- 2022
-
In: Proceedings of the Institution of mechanical engineers. Part C, journal of mechanical engineering science. - : SAGE Publications. - 0954-4062 .- 2041-2983. ; 236:3, s. 1631-1644
-
Journal article (peer-reviewed)abstract
- Due to the poor machinability of Ti6Al4V material, the cutting tool can easily suffer flank wear during the process of high-speed side milling, which reduces the tool life as well as the surface integrity of workpiece. Further, an effective method for predicting the flank wear of end mill during side milling of Ti6Al4V is lacking in the existing literature, which makes it difficult to improve the productivity of the overall process. To this end, in this study, a flank wear prediction model is constructed based on three main mechanisms: abrasive wear, adhesive wear, and diffusive wear. Subsequently, a normal stress model and temperature field model of wear land on the flank of end mill are established. Finally, these two models are incorporated in the flank wear model to obtain the variation rate of wear land width, which is regarded as a criterion to evaluate the reliability of the proposed flank wear prediction model of side mill. The prediction results are found to be in excellent agreement with the experimental results, which verifies the high prediction accuracy of the proposed model. Overall, this model can serve as a useful theoretical basis for the rational selection of tool geometry and cutting parameters.
|
|
| 21. |
- Yue, L., et al.
(author)
-
Novel InGaPBi single crystal grown by molecular beam epitaxy
- 2015
-
In: Applied Physics Express. - : IOP Publishing. - 1882-0786 .- 1882-0778. ; 8:4, s. Art. no. 041201-
-
Journal article (peer-reviewed)abstract
- InGaPBi crystalline thin films with up to 2.1% bismuth concentration have been grown on GaAs substrates by molecular beam epitaxy. Rutherford backscattering spectrometry confirms that the majority of Bi atoms are located at substitutional lattice sites. The films exhibit good surface, structural, and interface quality, and their strains can be tuned from tensile to compressive by increasing the Bi content. InBi LO and GaBi LO vibrational modes in Raman spectroscopy were observed, and their intensities increased with Bi concentration. A weak photoluminescence signal was observed at 1.78 eV at room temperature for the sample with a Bi content of 0.5%.
|
|
| 22. |
|
|
| 23. |
- Zhang, L., et al.
(author)
-
Improved Object Detection Method Utilizing YOLOv7-Tiny for Unmanned Aerial Vehicle Photographic Imagery
- 2023
-
In: Algorithms. - : Multidisciplinary Digital Publishing Institute (MDPI). - 1999-4893. ; 16:11
-
Journal article (peer-reviewed)abstract
- In unmanned aerial vehicle photographs, object detection algorithms encounter challenges in enhancing both speed and accuracy for objects of different sizes, primarily due to complex backgrounds and small objects. This study introduces the PDWT-YOLO algorithm, based on the YOLOv7-tiny model, to improve the effectiveness of object detection across all sizes. The proposed method enhances the detection of small objects by incorporating a dedicated small-object detection layer, while reducing the conflict between classification and regression tasks through the replacement of the YOLOv7-tiny model’s detection head (IDetect) with a decoupled head. Moreover, network convergence is accelerated, and regression accuracy is improved by replacing the Complete Intersection over Union (CIoU) loss function with a Wise Intersection over Union (WIoU) focusing mechanism in the loss function. To assess the proposed model’s effectiveness, it was trained and tested on the VisDrone-2019 dataset comprising images captured by various drones across diverse scenarios, weather conditions, and lighting conditions. The experiments show that mAP@0.5:0.95 and mAP@0.5 increased by 5% and 6.7%, respectively, with acceptable running speed compared with the original YOLOv7-tiny model. Furthermore, this method shows improvement over other datasets, confirming that PDWT-YOLO is effective for multiscale object detection.
|
|
| 24. |
- Zhang, L, et al.
(author)
-
Nanoscale distribution of Bi atoms in InP1−xBix
- 2017
-
In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 7:1, s. 12278-
-
Journal article (peer-reviewed)abstract
- The nanoscale distribution of Bi in InPBi is determined by atom probe tomography and transmission electron microscopy. The distribution of Bi atoms is not uniform both along the growth direction and within the film plane. A statistically high Bi-content region is observed at the bottom of the InPBi layer close to the InPBi/InP interface. Bi-rich V-shaped walls on the (-111) and (1-11) planes close to the InPBi/InP interface and quasi-periodic Bi-rich nanowalls in the (1-10) plane with a periodicity of about 100 nm are observed. A growth model is proposed to explain the formation of these unique Bi-related nanoscale features. These features can significantly affect the deep levels of the InPBi epilayer. The regions in the InPBi layer with or without these Bi-related nanostructures exhibit different optical properties.
|
|
| 25. |
- Zhu, X., et al.
(author)
-
Biodegradation mechanism of microcystin-LR by a novel isolate of Rhizobium sp. TH and the evolutionary origin of the mlrA gene
- 2016
-
In: International Biodeterioration & Biodegradation. - : Elsevier. - 0964-8305 .- 1879-0208. ; 115, s. 17-25
-
Journal article (peer-reviewed)abstract
- The frequent presence of microcystin (MC) in eutrophic water bodies worldwide poses a serious threat to ecosystems. Biodegradation has been extensively investigated as a main pathway for MC attenuation, and an mlr-dependent mechanism of MC degradation have been elucidated in detail. However, the evolutionary origin and the distribution of mlr genes in MC-degrading bacteria is poorly understood. In this study, a novel Rhizobium sp. TH, which is the first α-proteobacterial MC-degrading bacterium other than Sphingomonadales, was isolated. Strain TH degraded MC via the mlr-dependent mechanism with a first-order rate constant of 0.18–0.29 h−1 under near-natural conditions. The partial length mlr gene cluster was sequenced, and the function of its key gene, mlrA, was verified by heterologous expression in Escherichia coli. Phylogenetic analyses show that the mlrA gene initially arose in α-proteobacteria by vertical evolution, and the two strains from β- and γ-proteobacteria acquired it by horizontal gene transfer. Therefore, the mlrA gene mainly exists in α-proteobacteria but is seldom present in other bacteria. A pair of primers matching well with mlrA sequences reported so far were designed and could be used to determine the MC-degrading mechanism for novel isolates or to screen for MC-degrading ability among environmental samples.
|
|
| 26. |
|
|
| 27. |
- Barausse, Enrico, et al.
(author)
-
Prospects for fundamental physics with LISA
- 2020
-
In: General Relativity and Gravitation. - : SPRINGER/PLENUM PUBLISHERS. - 0001-7701 .- 1572-9532. ; 52:8
-
Journal article (other academic/artistic)abstract
- In this paper, which is of programmatic rather than quantitative nature, we aim to further delineate and sharpen the future potential of the LISA mission in the area of fundamental physics. Given the very broad range of topics that might be relevant to LISA,we present here a sample of what we view as particularly promising fundamental physics directions. We organize these directions through a "science-first" approach that allows us to classify how LISA data can inform theoretical physics in a variety of areas. For each of these theoretical physics classes, we identify the sources that are currently expected to provide the principal contribution to our knowledge, and the areas that need further development. The classification presented here should not be thought of as cast in stone, but rather as a fluid framework that is amenable to change with the flow of new insights in theoretical physics.
|
|
| 28. |
- Chen, J., et al.
(author)
-
Distributed Control of Multi-Functional Grid-Tied Inverters for Power Quality Improvement
- 2021
-
In: IEEE Transactions on Circuits and Systems Part 1. - : Institute of Electrical and Electronics Engineers Inc.. - 1549-8328 .- 1558-0806. ; 68:2, s. 918-928
-
Journal article (peer-reviewed)abstract
- Multi-functional grid-tied inverters (MFGTIs) have been investigated recently for improving the power quality (PQ) of microgrids (MGs) by exploiting the residual capacity (RC) of distributed generators. Several centralized and decentralized methods have been proposed to coordinate the MFGTIs. However, with the increasing number of the MFGTIs, it demands a method with improved reliability and flexibility, which are characteristics of distributed framework that has not been introduced into the PQ improvement (PQI) field before. In this paper, we propose a distributed consensus method to undertake the PQI task. The task is proportionally shared among the MFGTIs according to their instant RCs. Besides, most of the existing methods assume that the RCs of the MFGTIs are sufficient for tackling the PQ problem (PQP), which is not always true. In the case of insufficient RC, the active power output of each MFGTI is scaled down by the same factor determined by a proposed leader-follower protocol to make room for the task. In summary, the PQP is dealt with in both cases of sufficient and insufficient RC under the distributed control framework. Finally, simulations and hardware-in-the-loop experiments of an MG consisting of three 10kVA MFGTIs are presented to verify the effectiveness of the proposed methods. © 2004-2012 IEEE.
|
|
| 29. |
- Chen, Q. M., et al.
(author)
-
A new route toward light emission from Ge: tensile-strained quantum dots
- 2015
-
In: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3372 .- 2040-3364. ; 7:19, s. 8725-8730
-
Journal article (peer-reviewed)abstract
- The tensile-strained Ge quantum dot (QD) is proposed as a new route for the realization of direct band gap conversion in Ge. Ge QDs were successfully grown on an InP substrate by molecular beam epitaxy. The strain field in the QDs were analyzed by high resolution transmission electron microscopy and simulated by the finite element method based on the measured geometries. The strain field in the QDs is found to be non-uniform and the shear component plays a significant role in the energy band structure, leading to larger required hydrostatic strain than that in the Ge thin films under biaxial strain to become a direct band gap.
|
|
| 30. |
|
|
| 31. |
- Chen, X, et al.
(author)
-
Negative thermal quenching of below-bandgap photoluminescence in InPBi
- 2017
-
In: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 110:5
-
Journal article (peer-reviewed)abstract
- This paper reports a temperature-dependent (10-280 K) photoluminescence (PL) study of below-bandgap electron-hole recombinations and anomalous negative thermal quenching of PL intensity in InP1- xBix (x = 0.019 and 0.023). Four PL features are well resolved by curve-fitting of the PL spectra, of which the energies exhibit different temperature dependence. The integral intensities of the two high-energy features diminish monotonically as temperature rises up, while those of the two low-energy features decrease below but increase anomalously above 180 K. A phenomenological model is established that the residual electrons in the final state of the PL transition transfer into nonradiative state via thermal hopping, and the thermal hopping produces in parallel holes in the final state and hence enhances the radiative recombination significantly. A reasonable interpretation of the PL processes in InPBi is achieved, and the activation energies of the PL quenching and thermal hopping are deduced. © 2017 Author(s).
|
|
| 32. |
- Chen, Z., et al.
(author)
-
An iteration-based algorithm for two-pass flute grinding of slide round milling tools
- 2020
-
In: The International Journal of Advanced Manufacturing Technology. - : Springer Nature. - 0268-3768 .- 1433-3015. ; 111:9-10, s. 2533-2543
-
Journal article (peer-reviewed)abstract
- Solid end mill cutting tools are widely used in machining of curved surface parts in many industrial sectors, e.g., aerospace, automotive, and energy. Grinding is one of the most important processes in the manufacturing of the tools, and the movement of the grinding wheel closely influences the key parameters of helical groove cross-section, i.e., rake angle γo, inner core radius Rc, outer core radius Rcb, and edge width Ew, as well as chip removal capacity. However, a “closed” flute of a tool, which is one style of flute, may cause many problems if grinding it by one-pass, e.g., grinding wheel dressing to adapt to the change of flute parameters. To solve the problem in “closed” flute grinding, this paper proposes a two-pass flute grinding based on the iteration method. Within the context, some parameters and rules are identified in modeling of the two-pass grinding to control grinding wheel width and to smoothen grinding marks between the two passes of grinding. Finally, the method is implemented and validated by a set of numeric simulations and experiments. The results show that the errors of core radius, rake angle, edge width, and big core radius of the two ground tools are 1.1%, 2.0%, 3.4%, and 2.2%, respectively, which are within the designed tolerances.
|
|
| 33. |
- D'Angiolo, M., et al.
(author)
-
A yeast living ancestor reveals the origin of genomic introgressions
- 2020
-
In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 587, s. 420-425
-
Journal article (peer-reviewed)abstract
- A yeast clonal descendant of an ancient hybridization event is identified and sheds light on the early evolution of the Saccharomyces cerevisiae Alpechin lineage and its abundant Saccharomyces paradoxus introgressions. Genome introgressions drive evolution across the animal(1), plant(2) and fungal(3) kingdoms. Introgressions initiate from archaic admixtures followed by repeated backcrossing to one parental species. However, how introgressions arise in reproductively isolated species, such as yeast(4), has remained unclear. Here we identify a clonal descendant of the ancestral yeast hybrid that founded the extant Saccharomyces cerevisiae Alpechin lineage(5), which carries abundant Saccharomyces paradoxus introgressions. We show that this clonal descendant, hereafter defined as a 'living ancestor', retained the ancestral genome structure of the first-generation hybrid with contiguous S. cerevisiae and S. paradoxus subgenomes. The ancestral first-generation hybrid underwent catastrophic genomic instability through more than a hundred mitotic recombination events, mainly manifesting as homozygous genome blocks generated by loss of heterozygosity. These homozygous sequence blocks rescue hybrid fertility by restoring meiotic recombination and are the direct origins of the introgressions present in the Alpechin lineage. We suggest a plausible route for introgression evolution through the reconstruction of extinct stages and propose that genome instability allows hybrids to overcome reproductive isolation and enables introgressions to emerge.
|
|
| 34. |
- Fan, W., et al.
(author)
-
Investigation of magnetization dynamics damping in Ni80Fe20/Nd-Cu bilayer at room temperature
- 2018
-
In: AIP Advances. - : American Institute of Physics (AIP). - 2158-3226. ; 8:5
-
Journal article (peer-reviewed)abstract
- Focusing on the Ni80Fe20 (Py)/Nd-Cu bilayers, the magnetization dynamic damping from spin pumping effect is investigated systematically by doping itinerant Cu in rear earth metal Nd. Various Ta/Py/Nd1-xCux/Ta/Si films with x = 0%, 16%, 38%, 46% and 58% are prepared by magnetron sputtering. For every content of Cu, the thickness of Nd-Cu layer is changed from 1 nm to 32 nm. The damping coefficient increases with increasing the thickness of Nd-Cu layer, which shows the trend of the spin pumping behavior. Also, with increasing Cu concentration in the Nd-Cu layer, the damping coefficient decreases, implying that the spin-orbit coupling in Nd-Cu layer is indeed cut down by high itinerant of Cu dopants. It is interesting that the spin diffusion length (λSD) in the Nd-Cu layer for different Cu dopants is not found to increase monotonously.
|
|
| 35. |
|
|
| 36. |
- Forsberg, U., et al.
(author)
-
Recoil-α-fission and recoil-α-α-fission events observed in the reaction 48Ca + 243Am
- 2016
-
In: Nuclear Physics, Section A. - : Elsevier BV. - 0375-9474. ; 953, s. 117-138
-
Journal article (peer-reviewed)abstract
- Products of the fusion-evaporation reaction 48Ca + 243Am were studied with the TASISpec set-up at the gas-filled separator TASCA at the GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany. Amongst the detected thirty correlated α-decay chains associated with the production of element Z=115, two recoil-α-fission and five recoil-α-α-fission events were observed. The latter five chains are similar to four such events reported from experiments performed at the Dubna gas-filled separator, and three such events reported from an experiment at the Berkeley gas-filled separator. The four chains observed at the Dubna gas-filled separator were assigned to start from the 2n-evaporation channel 289115 due to the fact that these recoil-α-α-fission events were observed only at low excitation energies. Contrary to this interpretation, we suggest that some of these recoil-α-α-fission decay chains, as well as some of the recoil-α-α-fission and recoil-α-fission decay chains reported from Berkeley and in this article, start from the 3n-evaporation channel 288115.
|
|
| 37. |
- Ge, Q., et al.
(author)
-
Active contour evolved by joint probability classification on Riemannian manifold
- 2016
-
In: Signal, Image and Video Processing. - : Springer London. - 1863-1703 .- 1863-1711. ; 10:7, s. 1257-1264
-
Journal article (peer-reviewed)abstract
- In this paper, we present an active contour model for image segmentation based on a nonparametric distribution metric without any intensity a priori of the image. A novel nonparametric distance metric, which is called joint probability classification, is established to drive the active contour avoiding the instability induced by multimodal intensity distribution. Considering an image as a Riemannian manifold with spatial and intensity information, the contour evolution is performed on the image manifold by embedding geometric image feature into the active contour model. The experimental results on medical and texture images demonstrate the advantages of the proposed method.
|
|
| 38. |
- Hu, Zhili, 1983, et al.
(author)
-
The effect of modulus on the performance of thermal conductive adhesives
- 2010
-
In: Proceedings - 2010 11th International Conference on Electronic Packaging Technology and High Density Packaging, ICEPT-HDP 2010; Xi'an; 16 August 2010 through 19 August 2010. - 9781424481422 ; :Article number 5582884, s. 648-651
-
Conference paper (peer-reviewed)abstract
- By analyzing the effect of modulus of epoxy and modulus of filler particles on the thermal conductivity of thermal conductive adhesives (TCA), this paper concludes, in contrast to intuition, that the stiffer epoxy will generate a larger contact area, and the "soft" epoxy with modulus of 0.5GPa will create the largest contact area, hence the highest thermal conductivity. Therefore, it is advisable to adopt softer epoxy in TCA. On the other hand, this paper finds that if the shrinkage of epoxy is low, i.e. 1% linear shrinkage, fillers composed of a mixture of Ag flakes and certain high stiffness material will cause a higher thermal conductivity, i.e. 7% larger than that of pure Ag fillers. This suggests that with low shrinkage epoxy, it is advisable to mix Ag flakes with high stiffness particles, e.g. Diamond or SiC. However, when linear shrinkage of epoxy is high, i.e. 3%, the highest thermal conductivity is achieved by using pure Ag fillers. Therefore, in such cases it is not advisable to use Bi-model. © 2010 IEEE.
|
|
| 39. |
- Kattge, Jens, et al.
(author)
-
TRY plant trait database - enhanced coverage and open access
- 2020
-
In: Global Change Biology. - : Wiley-Blackwell. - 1354-1013 .- 1365-2486. ; 26:1, s. 119-188
-
Journal article (peer-reviewed)abstract
- Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.
|
|
| 40. |
|
|
| 41. |
- Li, J., et al.
(author)
-
Genome instability footprint under rapamycin and hydroxyurea treatments
- 2023
-
In: PLoS Genetics. - 1553-7404. ; 19:11
-
Journal article (peer-reviewed)abstract
- The mutational processes dictating the accumulation of mutations in genomes are shaped by genetic background, environment and their interactions. Accurate quantification of mutation rates and spectra under drugs has important implications in disease treatment. Here, we used whole-genome sequencing and time-resolved growth phenotyping of yeast mutation accumulation lines to give a detailed view of the mutagenic effects of rapamycin and hydroxyurea on the genome and cell growth. Mutation rates depended on the genetic backgrounds but were only marginally affected by rapamycin. As a remarkable exception, rapamycin treatment was associated with frequent chromosome XII amplifications, which compensated for rapamycin induced rDNA repeat contraction on this chromosome and served to maintain rDNA content homeostasis and fitness. In hydroxyurea, a wide range of mutation rates were elevated regardless of the genetic backgrounds, with a particularly high occurrence of aneuploidy that associated with dramatic fitness loss. Hydroxyurea also induced a high T-to-G and low C-to-A transversion rate that reversed the common G/C-to-A/T bias in yeast and gave rise to a broad range of structural variants, including mtDNA deletions. The hydroxyurea mutation footprint was consistent with the activation of error-prone DNA polymerase activities and non-homologues end joining repair pathways. Taken together, our study provides an in-depth view of mutation rates and signatures in rapamycin and hydroxyurea and their impact on cell fitness, which brings insights for assessing their chronic effects on genome integrity. As the ultimate source of genetic variation, mutation plays critical roles in evolution. An accurate depiction of its intrinsic rate and signature can help us understand the genetic basis of biodiversity and diseases. However, the ubiquitous existence of natural selection often leads to bias for the observable mutations in natural populations. To minimize such confounding effect introduced by selection, we applied evolution experiment by random single-cell bottlenecks, which allows almost all kinds of mutations to accumulate in an unbiased way. With this setup, we examined the mutation rates and signatures of yeast cells in two commonly used chemotherapy drugs that impairs essential cellular functions such as DNA and protein synthesis. We found elevated mutation rates for a wide range of genetic variants, accompanied by dramatic fitness loss in hydroxyurea. The mutational signatures suggest the involvement of low fidelity DNA replication and repair processes. The mutagenic effects of rapamycin are marginal but with frequent chromosome XII amplifications that compensate for rapamycin-induced rDNA contraction on this chromosome. Our findings provide an example of how such experiments on model organisms can help us better understand the chronic mutagenic effects of drugs and their underlying biological mechanisms.
|
|
| 42. |
- Liang, S., et al.
(author)
-
Intelligent manufacturing systems : A review
- 2018
-
In: International Journal of Mechanical Engineering and Robotics Research. - : International Journal of Mechanical Engineering and Robotics Research. - 2278-0149. ; 7:3, s. 324-330
-
Research review (peer-reviewed)abstract
- Manufacturing factories, having continuous pursuit of productivity and quality, often meet challenges in coping with high production complexities and uncertainties. These are the areas in which traditional manufacturing paradigms underperform due to the limitation of human operators' ability to cope with these complexities, uncertainties, understanding/memorizing big data, and also their inability to make time demanding decisions. Intelligent manufacturing systems, on the other hand, can yield superior results compared to traditional manufacturing systems as they are capable of analyzing, self-learning, apprehending complexities and are also able to store and analyze large amounts of data to obtain increased quality of the product and lower production cost while shortening the time-to-market. The aim of this paper is to outline the recent accomplishments and developments in intelligent scheduling, process optimization, control, and maintenance. For each aspect, concepts, requirements, application implemented, and methodologies deployed are also presented.
|
|
| 43. |
- Liu, X., et al.
(author)
-
Intelligent Machining Technology in Cutting Process
- 2018
-
In: Jixie Gongcheng Xuebao/Journal of Mechanical Engineering. - : Editorial Office of Chinese Journal of Mechanical Engineering. - 0577-6686. ; 54:16, s. 45-61
-
Journal article (peer-reviewed)abstract
- Metal cutting is a very complex process. In the cutting process, the related knowledge and theories of physics, chemistry, mechanics, materials science, vibration, tribology, heat transfer and other fields are involved. The cutting process control has been the focus of the cutting research. With the development of machining technology and the coming of the Industry 4. 0, researchers are getting more concerned with the intelligent machining technology. It is an inevitable trend to apply the intelligent machining technology in the cutting process. The connotation and the application process of intelligent machining technology is expounded to investigate the critical technology in intelligent manufacturing. The research results in the simulation and optimization, cutting process condition monitoring, and optimization control are reviewed. Through analyzing the application prospect and problems of intelligent machining technology, the main scientific problems and key technologies to be solved are proposed. Intelligent machining is the development direction of processing technology. The application of intelligent machining technology in the cutting process will bring another technological revolution in the manufacturing industry.
|
|
| 44. |
- Ma, Y. M., et al.
(author)
-
Implementation of trait-based ozone plant sensitivity in the YaleInteractive terrestrial Biosphere model v1.0 to assess global vegetationdamage
- 2023
-
In: Geoscientific Model Development. - 1991-959X. ; 16:8, s. 2261-2276
-
Journal article (peer-reviewed)abstract
- A major limitation in modeling global ozone (O-3) vegetation damage has long been the reliance on empirical O-3 sensitivity parameters derived from a limited number of species and applied at the level of plant functional types (PFTs), which ignore the large interspecific variations within the same PFT. Here, we present a major advance in large-scale assessments of O-3 plant injury by linking the trait leaf mass per area (LMA) and plant O-3 sensitivity in a broad and global perspective. Application of the new approach and a global LMA map in a dynamic global vegetation model reasonably represents the observed interspecific responses to O-3 with a unified sensitivity parameter for all plant species. Simulations suggest a contemporary global mean reduction of 4.8% in gross primary productivity by O-3, with a range of 1.1 %-12.6% for varied PFTs. Hotspots with damage > 10% are found in agricultural areas in the eastern US, western Europe, eastern China, and India, accompanied by moderate to high levels of surface O-3. Furthermore, we simulate the distribution of plant sensitivity to O-3, which is highly linked with the inherent leaf trait trade-off strategies of plants, revealing high risks for fast-growing species with low LMA, such as crops, grasses, and deciduous trees.
|
|
| 45. |
- Mozzachiodi, S., et al.
(author)
-
Aborting meiosis allows recombination in sterile diploid yeast hybrids
- 2021
-
In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 12:1
-
Journal article (peer-reviewed)abstract
- Hybrids are often considered evolutionary dead ends because they do not generate viable offspring. Here, the authors show that sterile yeast hybrids generate genetic diversity through meiotic-like recombination by aborting meiosis and return to asexual growth. Hybrids between diverged lineages contain novel genetic combinations but an impaired meiosis often makes them evolutionary dead ends. Here, we explore to what extent an aborted meiosis followed by a return-to-growth (RTG) promotes recombination across a panel of 20 Saccharomyces cerevisiae and S. paradoxus diploid hybrids with different genomic structures and levels of sterility. Genome analyses of 275 clones reveal that RTG promotes recombination and generates extensive regions of loss-of-heterozygosity in sterile hybrids with either a defective meiosis or a heavily rearranged karyotype, whereas RTG recombination is reduced by high sequence divergence between parental subgenomes. The RTG recombination preferentially arises in regions with low local heterozygosity and near meiotic recombination hotspots. The loss-of-heterozygosity has a profound impact on sexual and asexual fitness, and enables genetic mapping of phenotypic differences in sterile lineages where linkage analysis would fail. We propose that RTG gives sterile yeast hybrids access to a natural route for genome recombination and adaptation.
|
|
| 46. |
- Pan, W. W., et al.
(author)
-
Growth and material properties of InPBi thin films using gas source molecular beam epitaxy
- 2016
-
In: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388. ; 656, s. 777-783
-
Journal article (peer-reviewed)abstract
- The effects of Bi, In flux and PH3 pressure on Bi incorporation, structural and transport properties of InPBi grown by gas source molecular beam epitaxy have been systematically studied. Incorporation of Bi behaves like a dopant and its content increases linearly with Bi flux and inversely with the InP growth rate (In flux), and is independent of the PH3 pressure studied. High PH3 pressure causes rough surface and introduction of Bi improves surface quality. Intrinsic InP grown at a low temperature reveals n-type due to the P-ln antisite defects and the electron density is proportional to the PH3 pressure and inversely proportional to the InP growth rate. Incorporation of Bi induces p-type dopant that compensates the background electron concentration but doesn't degrade the electron mobility for the Bi content up to 2.4%. These results suggest that there is still a large room left to optimize material quality and maximize Bi incorporation in InPBi using gas source molecular beam epitaxy.
|
|
| 47. |
- Pan, W. W., et al.
(author)
-
Raman scattering studies of dilute InP1-xBix alloys reveal unusually strong oscillator strength for Bi-induced modes
- 2015
-
In: Semiconductor Science and Technology. - : IOP Publishing. - 1361-6641 .- 0268-1242. ; 30:9
-
Journal article (peer-reviewed)abstract
- Room-temperature Raman scattering studies of new InP1-xBix alloys grown by molecular beam epitaxy are reported. Two new Bi-induced vibrations observed at 149 and 171 cm-1 are assigned to InBi-like TO and LO phonon modes, respectively, and exhibit an unusually strong intensity for the dilute regime. Two additional modes at 311 and 337 cm-1 are resolved as well with unknown origins. The Raman intensities of the InBi-like TO and LO bands, as well as the new mode at 337 cm-1, exhibit strong and linear dependence on the Bi concentration for the composition range studied, 0.003 ≤ x ≤ 0.023. This correlation may serve as a fast and convenient means of characterizing bismuth composition not only in the ternary alloy InP1-xBix but also in the quaternaries such as In1-yGayP1-xBix and In1-yAlyP1-xBix.
|
|
| 48. |
- Pelaz, B, et al.
(author)
-
Diverse Applications of Nanomedicine
- 2017
-
In: ACS nano. - : American Chemical Society (ACS). - 1936-086X .- 1936-0851. ; 11:3, s. 2313-2381
-
Journal article (peer-reviewed)
|
|
| 49. |
|
|
| 50. |
- Shen, S., et al.
(author)
-
Manipulating crystals through photoexcitation-induced molecular realignment
- 2021
-
In: Journal of Materials Chemistry C. - : Royal Society of Chemistry (RSC). - 2050-7526 .- 2050-7534. ; 9:35, s. 11707-11714
-
Journal article (peer-reviewed)abstract
- Numerous efforts have been invested in improving the uniform rearrangement in photoinduced crystal engineering due to the fact that molecular ordering is hardly addressedviaa traditional photochemical process as a whole. Herein, we present a nonequilibrium strategy, photoexcitation-induced molecular realignment, to manipulate crystal growth and transformation. This strategy allows a dynamic change of molecular conformation upon continuous photoirradiation, wherein the molecular structure remains intact. Consequently, crystal photomanipulation from solution growth to single crystals, polycrystals, and finally to doped films is achieved, accompanied by the phototuning of a series of crystal optical behaviors (e.g.absorption, refraction, fluorescence, and room-temperature phosphorescence). The developed materials are stable because of the molecular conformation kinetically trapped within the minimum energy on the basis of a steady-state design conception. This strategy, relying on the materialization of photoexcitation, provides a paradigm for controlling molecular ordering by light.
|
|
