| 1. |
- Zhang, Li, et al.
(author)
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Characterization of anti-BCG benz[α]anthraquinones and new siderophores from a Xinjiang desert-isolated rare actinomycete Nocardia sp. XJ31
- 2020
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In: Applied Microbiology and Biotechnology. - : Springer Science and Business Media LLC. - 0175-7598 .- 1432-0614. ; 104:19, s. 8267-8278
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Journal article (peer-reviewed)abstract
- The current global demand for novel anti-TB drugs has drawn urgent attention on the discovery of natural product compounds with anti-TB activity. Lots of efforts have emphasized on environmental samples from unexplored or underexplored natural habits and identified numerous rare actinomycete taxa producing structurally diverse bioactive natural products. Herein, we report a survey of the rare actinobacteria diversity in Xinjiang region together with the discovery of anti-TB active natural products from these strains. We have collected 17 soil samples at different sites with different environmental conditions, from which 39 rare actinobacteria were identified by using a selective isolation strategy with 5 media variations. Among those isolated strains, XJ31 was identified as a new Nocardia sp. based on 16S rRNA gene analysis. Through one strain-many compounds (OSMAC) strategy combined with anti-Bacillus Calmette-Guérin bioassay-guided isolation, two groups of compounds were identified. They were twelve siderophores (nocardimicins, 1-12) and two anthraquinones (brasiliquinones, 13 and 14) and ten of them were identified as new compounds. The structures of the purified compounds were elucidated using HR-ESI-MS, 1D NMR, and 2D NMR techniques. The anti-TB bioassays revealed that the two benz[α]anthraquinones have potent activity against BCG (MICs = 25 μM), which can be used as a promising start point for further anti-TB drug development.
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| 2. |
- Alimena, Juliette, et al.
(author)
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Searching for long-lived particles beyond the Standard Model at the Large Hadron Collider
- 2020
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In: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 47:9
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Journal article (peer-reviewed)abstract
- Particles beyond the Standard Model (SM) can generically have lifetimes that are long compared to SM particles at the weak scale. When produced at experiments such as the Large Hadron Collider (LHC) at CERN, these long-lived particles (LLPs) can decay far from the interaction vertex of the primary proton-proton collision. Such LLP signatures are distinct from those of promptly decaying particles that are targeted by the majority of searches for new physics at the LHC, often requiring customized techniques to identify, for example, significantly displaced decay vertices, tracks with atypical properties, and short track segments. Given their non-standard nature, a comprehensive overview of LLP signatures at the LHC is beneficial to ensure that possible avenues of the discovery of new physics are not overlooked. Here we report on the joint work of a community of theorists and experimentalists with the ATLAS, CMS, and LHCb experiments-as well as those working on dedicated experiments such as MoEDAL, milliQan, MATHUSLA, CODEX-b, and FASER-to survey the current state of LLP searches at the LHC, and to chart a path for the development of LLP searches into the future, both in the upcoming Run 3 and at the high-luminosity LHC. The work is organized around the current and future potential capabilities of LHC experiments to generally discover new LLPs, and takes a signature-based approach to surveying classes of models that give rise to LLPs rather than emphasizing any particular theory motivation. We develop a set of simplified models; assess the coverage of current searches; document known, often unexpected backgrounds; explore the capabilities of proposed detector upgrades; provide recommendations for the presentation of search results; and look towards the newest frontiers, namely high-multiplicity 'dark showers', highlighting opportunities for expanding the LHC reach for these signals.
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| 3. |
- Hu, Jingyu, et al.
(author)
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Integrated multi-material and multi-scale optimization of compliant structure with embedded movable piezoelectric actuators
- 2024
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In: Computer Methods in Applied Mechanics and Engineering. - 0045-7825. ; 421
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Journal article (peer-reviewed)abstract
- Piezoelectric actuators embedded in compliant structures have many potential applications, which call for effective design approaches. Existing optimization driven design methods focus on the piezoelectric actuator location or the macro topology of the host compliant structure while ignoring the possibility to exploit the use of multiple materials and hierarchical material design. In this study, an integrated, density-based multi-material and multi-scale optimization method for compliant structures with embedded movable piezoelectric actuators is proposed. The design variables in the optimization represent the location of the piezoelectric actuators and the layout of the macro/micro host structures. To mitigate the risk of suboptimal designs, the three sets of design variables are simultaneously optimized using gradient-based optimization where the gradients are computed using the adjoint method. A material interpolation model that describes the piezoelectric actuators, multiple lattice materials of the host structure as well as their coating layer is proposed. To illustrate the formulation, several compliant structures embedded with movable piezoelectric actuators are designed such that the displacement at an output port is maximized. Macro and micro volume fractions, and overlapping of piezoelectric actuators are constrained in the optimization.
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| 4. |
- Kristan, Matej, et al.
(author)
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The Visual Object Tracking VOT2017 challenge results
- 2017
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In: 2017 IEEE INTERNATIONAL CONFERENCE ON COMPUTER VISION WORKSHOPS (ICCVW 2017). - : IEEE. - 9781538610343 ; , s. 1949-1972
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Conference paper (peer-reviewed)abstract
- The Visual Object Tracking challenge VOT2017 is the fifth annual tracker benchmarking activity organized by the VOT initiative. Results of 51 trackers are presented; many are state-of-the-art published at major computer vision conferences or journals in recent years. The evaluation included the standard VOT and other popular methodologies and a new "real-time" experiment simulating a situation where a tracker processes images as if provided by a continuously running sensor. Performance of the tested trackers typically by far exceeds standard baselines. The source code for most of the trackers is publicly available from the VOT page. The VOT2017 goes beyond its predecessors by (i) improving the VOT public dataset and introducing a separate VOT2017 sequestered dataset, (ii) introducing a realtime tracking experiment and (iii) releasing a redesigned toolkit that supports complex experiments. The dataset, the evaluation kit and the results are publicly available at the challenge website(1).
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| 5. |
- Boen, Rune, et al.
(author)
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Beyond the global brain differences : intraindividual variability differences in 1q21.1 distal and 15q11.2 bp1-bp2 deletion carriers
- 2024
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In: Biological Psychiatry. - 0006-3223 .- 1873-2402. ; 95:2, s. 147-160
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Journal article (peer-reviewed)abstract
- Background: Carriers of the 1q21.1 distal and 15q11.2 BP1-BP2 copy number variants exhibit regional and global brain differences compared with noncarriers. However, interpreting regional differences is challenging if a global difference drives the regional brain differences. Intraindividual variability measures can be used to test for regional differences beyond global differences in brain structure.Methods: Magnetic resonance imaging data were used to obtain regional brain values for 1q21.1 distal deletion (n = 30) and duplication (n = 27) and 15q11.2 BP1-BP2 deletion (n = 170) and duplication (n = 243) carriers and matched noncarriers (n = 2350). Regional intra-deviation scores, i.e., the standardized difference between an individual's regional difference and global difference, were used to test for regional differences that diverge from the global difference.Results: For the 1q21.1 distal deletion carriers, cortical surface area for regions in the medial visual cortex, posterior cingulate, and temporal pole differed less and regions in the prefrontal and superior temporal cortex differed more than the global difference in cortical surface area. For the 15q11.2 BP1-BP2 deletion carriers, cortical thickness in regions in the medial visual cortex, auditory cortex, and temporal pole differed less and the prefrontal and somatosensory cortex differed more than the global difference in cortical thickness.Conclusions: We find evidence for regional effects beyond differences in global brain measures in 1q21.1 distal and 15q11.2 BP1-BP2 copy number variants. The results provide new insight into brain profiling of the 1q21.1 distal and 15q11.2 BP1-BP2 copy number variants, with the potential to increase understanding of the mechanisms involved in altered neurodevelopment.
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| 6. |
- Fan, Jingyu, et al.
(author)
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On the heat transfer enhancement based on micro-scale air impingingment jets with microstructure heat sink in electronics cooling
- 2006
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In: 2006 Conference on High Density Microsystem Design and Packaging and Component Failure Analysis, HDP'06; Shanghai; China; 27 June 2006 through 28 June 2006. - 9781424404889 ; , s. 120-124
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Conference paper (peer-reviewed)abstract
- A conceptual heat transfer enhancement scheme in electronic cooling is analyzed on the basis of micro-scale impinging jet array with microstructure heat sink. The cooling performance of the micro impinging jet array is discussed and compared with that of conventional large-scale jet impingement cooling, and the pressure drop due to the induced crossflow is a vital factor for the former. The primary mechanisms by which the different types of the microstructure heat sinks affect the heat transfer rate as well as the pressure drop for the micro impinging jet array are empirically analyzed and discussed. In any case, it is necessary to make a proper compromise between the enhanced heat transfer rate and the acceptable pressure drop for the removal of high chip heat fluxes by combining the micro impinging jet array with micro-structured surface.
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| 7. |
- Gao, Jingyu, et al.
(author)
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Three-Dimensional Transient Electromagnetic Forward Modeling for Simulating Arbitrary Source Waveform Using Convolution Approach
- 2023
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In: IEEE Transactions on Geoscience and Remote Sensing. - : Institute of Electrical and Electronics Engineers Inc.. - 0196-2892 .- 1558-0644. ; 61
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Journal article (peer-reviewed)abstract
- The transient electromagnetic (TEM) method utilizes artificial transmitters and measures electromagnetic (EM) responses to reveal the resistivity information of the subsurface. The current waveform of transmitters has nonnegligible effects on induced fields. Therefore, 3-D TEM forward modeling algorithms need the capability of simulating arbitrary waveforms to obtain accurate responses. In time-stepping-based 3-D TEM forward modeling, the source term (ST) approach is frequently used, which employs the source current density to model the waveform variation during time-stepping. The ST approach, however, requires fine-time discretization to describe complex waveforms, which could significantly raise the computational cost. We present a robust convolution (Conv) approach that computes the convolution between the time derivative of the waveform and the step-off response to incorporate the waveform effects in 3-D TEM modeling. The Conv approach does not discretize the waveform using time steps. Hence, it is advantageous when modeling full-waveform cases. The developed algorithm is based on the finite-element (FE) method using unstructured grids and the implicit backward Euler approach. Both galvanic and inductive transmitters are incorporated. Ground and airborne TEM surveys are tested using an actual airborne TEM waveform, a full waveform of the 2(n) -sequence pseudorandom signal, and various synthetic waveforms. Accuracy is validated against the 1-D and 3-D solutions of published studies. The ST and Conv approaches are compared. Synthetic examples show that the latter approach simplifies the waveform incorporation in TEM modeling and substantially improves time-stepping efficiency without sacrificing accuracy.
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| 8. |
- Lyu, Yezhe, 1987-, et al.
(author)
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Effect of Tin on Microstructure and Mechanical Properties of Compacted Graphite Iron
- 2015
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In: International Journal of Cast Metals Research. - : Maney Publishing. - 1364-0461 .- 1743-1336. ; 28:5, s. 263-268
-
Journal article (peer-reviewed)abstract
- This experiment investigated the effect of tin in an amount up to 0.121 wt.% on the microstructure and mechanical properties of compacted graphite iron (CGI). Graphite and matrix evolution was emphasized with the help of scanning electron microscopy. The results indicate that Sn in experimental range reduces graphite size. Pearlite quantity would increase with the increasing Sn and reaches over 95% when Sn is greater than 0.057 wt.%. Sn helps to narrow the lamellar spacing of pearlite from sorbitic pearlite (320 nm) to troostitic pearlite (83 nm) when Sn increases from 0.003 wt.% to 0.057 wt.%. Appropriate Sn addition promotes the tensile strength and impact toughness and the samples containing 0.057 wt.% Sn perform the highest values of 410.7 MPa and 9.11 J/cm2, respectively. Elongation declines with increasing Sn content because of the emergence of more pearlite. Samples containing excessive Sn experience sharply deterioration in mechanical properties due brittle cementite.
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| 9. |
- Man, Zhang, et al.
(author)
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Facile one-step synthesis and enhanced photocatalytic activity of WC/ferroelectric nanocomposite
- 2021
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In: Journal of Materials Chemistry A. - : Royal Society of Chemistry. - 2050-7488 .- 2050-7496. ; 9:40, s. 22861-22870
-
Journal article (peer-reviewed)abstract
- The development of noble-metal-free co-catalysts is seen as a viable strategy for improving the performance of semiconductor photocatalysts. Although the photocatalytic efficiency of ferroelectrics is typically low, it can be enhanced through the incorporation of a co-catalyst into nanocomposites. Here, we demonstrate the influence of ferroelectricity on the decolorization of rhodamine B under simulated solar light using RbBi2Ti2NbO10 and compared the performance with that of non-ferroelectric RbBi2Nb5O16. The decolorization rate for RbBi2Ti2NbO10 was 5 times greater than that of RbBi2Nb5O16. This behaviour can be explained in terms of ferroelectric polarization, which drives the separation of charge carriers. The photocatalytic activity of RbBi2Ti2NbO10 was further enhanced to over 30 times upon preparing a nanocomposite with tungsten carbide (WC) through high energy ball milling. This enhancement was attributed not only to the increased specific surface area, but also to the incorporated WC co-catalyst, which also serves as a source of plasmonic hot electrons and extends the photocatalytic activity into the visible light range. The WC/RbBi2Ti2NbO10 nanocomposite shows interesting water oxidation properties and evolves O-2 with a rate of 68.5 mu mol h(-1) g(-1) and a quantum yield of 3% at 420 nm. This work demonstrates a simple route for preparing WC containing nano-ferroelectric composites for solar energy conversion applications.
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| 10. |
- Sonderby, Ida E., et al.
(author)
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Dose response of the 16p11.2 distal copy number variant on intracranial volume and basal ganglia
- 2020
-
In: Molecular Psychiatry. - : Nature Publishing Group. - 1359-4184 .- 1476-5578. ; 25:3, s. 584-602
-
Journal article (peer-reviewed)abstract
- Carriers of large recurrent copy number variants (CNVs) have a higher risk of developing neurodevelopmental disorders. The 16p11.2 distal CNV predisposes carriers to e.g., autism spectrum disorder and schizophrenia. We compared subcortical brain volumes of 12 16p11.2 distal deletion and 12 duplication carriers to 6882 non-carriers from the large-scale brain Magnetic Resonance Imaging collaboration, ENIGMA-CNV. After stringent CNV calling procedures, and standardized FreeSurfer image analysis, we found negative dose-response associations with copy number on intracranial volume and on regional caudate, pallidum and putamen volumes (β = −0.71 to −1.37; P < 0.0005). In an independent sample, consistent results were obtained, with significant effects in the pallidum (β = −0.95, P = 0.0042). The two data sets combined showed significant negative dose-response for the accumbens, caudate, pallidum, putamen and ICV (P = 0.0032, 8.9 × 10−6, 1.7 × 10−9, 3.5 × 10−12 and 1.0 × 10−4, respectively). Full scale IQ was lower in both deletion and duplication carriers compared to non-carriers. This is the first brain MRI study of the impact of the 16p11.2 distal CNV, and we demonstrate a specific effect on subcortical brain structures, suggesting a neuropathological pattern underlying the neurodevelopmental syndromes.
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| 11. |
- Sønderby, Ida E., et al.
(author)
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1q21.1 distal copy number variants are associated with cerebral and cognitive alterations in humans
- 2021
-
In: Translational Psychiatry. - : Nature Publishing Group. - 2158-3188. ; 11:1
-
Journal article (peer-reviewed)abstract
- Low-frequency 1q21.1 distal deletion and duplication copy number variant (CNV) carriers are predisposed to multiple neurodevelopmental disorders, including schizophrenia, autism and intellectual disability. Human carriers display a high prevalence of micro- and macrocephaly in deletion and duplication carriers, respectively. The underlying brain structural diversity remains largely unknown. We systematically called CNVs in 38 cohorts from the large-scale ENIGMA-CNV collaboration and the UK Biobank and identified 28 1q21.1 distal deletion and 22 duplication carriers and 37,088 non-carriers (48% male) derived from 15 distinct magnetic resonance imaging scanner sites. With standardized methods, we compared subcortical and cortical brain measures (all) and cognitive performance (UK Biobank only) between carrier groups also testing for mediation of brain structure on cognition. We identified positive dosage effects of copy number on intracranial volume (ICV) and total cortical surface area, with the largest effects in frontal and cingulate cortices, and negative dosage effects on caudate and hippocampal volumes. The carriers displayed distinct cognitive deficit profiles in cognitive tasks from the UK Biobank with intermediate decreases in duplication carriers and somewhat larger in deletion carriers-the latter potentially mediated by ICV or cortical surface area. These results shed light on pathobiological mechanisms of neurodevelopmental disorders, by demonstrating gene dose effect on specific brain structures and effect on cognitive function.
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| 12. |
- van der Meer, Dennis, et al.
(author)
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Association of Copy Number Variation of the 15q11.2 BP1-BP2 Region With Cortical and Subcortical Morphology and Cognition
- 2020
-
In: JAMA psychiatry. - : American Medical Association (AMA). - 2168-6238 .- 2168-622X. ; 77:4, s. 420-430
-
Journal article (peer-reviewed)abstract
- Importance: Recurrent microdeletions and duplications in the genomic region 15q11.2 between breakpoints 1 (BP1) and 2 (BP2) are associated with neurodevelopmental disorders. These structural variants are present in 0.5% to 1.0% of the population, making 15q11.2 BP1-BP2 the site of the most prevalent known pathogenic copy number variation (CNV). It is unknown to what extent this CNV influences brain structure and affects cognitive abilities.Objective: To determine the association of the 15q11.2 BP1-BP2 deletion and duplication CNVs with cortical and subcortical brain morphology and cognitive task performance.Design, Setting, and Participants: In this genetic association study, T1-weighted brain magnetic resonance imaging were combined with genetic data from the ENIGMA-CNV consortium and the UK Biobank, with a replication cohort from Iceland. In total, 203 deletion carriers, 45 247 noncarriers, and 306 duplication carriers were included. Data were collected from August 2015 to April 2019, and data were analyzed from September 2018 to September 2019.Main Outcomes and Measures: The associations of the CNV with global and regional measures of surface area and cortical thickness as well as subcortical volumes were investigated, correcting for age, age2, sex, scanner, and intracranial volume. Additionally, measures of cognitive ability were analyzed in the full UK Biobank cohort.Results: Of 45 756 included individuals, the mean (SD) age was 55.8 (18.3) years, and 23 754 (51.9%) were female. Compared with noncarriers, deletion carriers had a lower surface area (Cohen d = -0.41; SE, 0.08; P = 4.9 × 10-8), thicker cortex (Cohen d = 0.36; SE, 0.07; P = 1.3 × 10-7), and a smaller nucleus accumbens (Cohen d = -0.27; SE, 0.07; P = 7.3 × 10-5). There was also a significant negative dose response on cortical thickness (β = -0.24; SE, 0.05; P = 6.8 × 10-7). Regional cortical analyses showed a localization of the effects to the frontal, cingulate, and parietal lobes. Further, cognitive ability was lower for deletion carriers compared with noncarriers on 5 of 7 tasks.Conclusions and Relevance: These findings, from the largest CNV neuroimaging study to date, provide evidence that 15q11.2 BP1-BP2 structural variation is associated with brain morphology and cognition, with deletion carriers being particularly affected. The pattern of results fits with known molecular functions of genes in the 15q11.2 BP1-BP2 region and suggests involvement of these genes in neuronal plasticity. These neurobiological effects likely contribute to the association of this CNV with neurodevelopmental disorders.
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| 13. |
- Zhang, Yan, 1976, et al.
(author)
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Experimental study of Electrical properties and stability of CNT bumps in high density interconnects
- 2013
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In: Proceedings of the IEEE Conference on Nanotechnology. - 1944-9399 .- 1944-9380. - 9781479906758 ; , s. 1085-1088
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Conference paper (peer-reviewed)abstract
- With the minimization development of electronic devices and products, nanotechnology and nanomaterials are widely applied in different fields of electronic packaging. Carbon nanotube (CNT) is an ideal material due to its excellent electrical and thermal conductivities. In the present paper, the application of CNT bundles as chip bumps was experimentally investigated. The electrical resistances of the CNT interconnects were measured, and the thermal and humidity test were conducted. In addition, the CNT forests on fine pitch copper lines under various environmental test conditions were observed to evaluate the stability. © 2013 IEEE.
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| 14. |
- Zhang, Yan, 1976, et al.
(author)
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Experimental Study on the Mechanical Reliability of Carbon Nanotubes
- 2013
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In: Proceedings of the 14 th International Conference on Electronics Packaging (ICEPT). - 9781479904990 ; , s. 105-108
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Conference paper (peer-reviewed)abstract
- Robust and reliable interconnect and effective heat management are two major concerns in the high-speed and high-power integrated circuit. Carbon nanotube (CNT) exhibits amazing mechanical, thermal and electronic properties due to the unique structure. Those superior features make CNTs preferable and promising for application in electronic components and devices. In the present paper, carbon nanotube bundles with an array pattern are fabricated, and then their mechanical strength and reliability are investigated experimentally. Different pressure loadings are applied on the surfaces of the CNT bundles and their deformation during loading process are observed. Furthermore, the responses of the CNT bundles under airflow impingement are studied. Various damage modes occur in the different loading conditions.
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| 15. |
- Zhang, Y., et al.
(author)
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Heat transfer analysis of phase change materials with metal foams
- 2021
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In: 2021 22nd International Conference on Electronic Packaging Technology, ICEPT 2021.
-
Conference paper (peer-reviewed)abstract
- With the development of electronic products towards high-density integration, high performance and multifunction, the working frequencies and power consumption rate of electronic components and devices increase substantially. The resulting temperature rise has a great impact on the operation and lifetime of electronic products. Transient temperature control and efficient heat dissipation are essential to the stability and reliability of the electronic components and products. Paraffin wax, as one of the most commonly used phase change materials, has been widely applied in many products requiring transient temperature control due to its melting temperature lying in the range of electronics operation conditions. However, the applicable scopes of phase change materials were limited due to their shortcomings of low thermal conductivity and heat dissipation. In the present paper, both metal forms and carbon nanomaterials are used as thermal enhancers to increase the conduction of paraffin wax, and the heat transfer characters of the composites are investigated by numerical method. The simulation results show that the introduction of Cu or Ni foam as heat conductive enhancers can significantly increase the effective thermal conductivity of paraffin wax composite. The thermal conductivity of the composite with Ni foams is 3.684 times higher than that of the paraffin wax, and the increase is 12.485 times when Cu foam is used instead of Ni foam. Furthermore, the heat transfer of the composites can be strengthened by adding carbon nanomaterials into the paraffin wax so as to increase the thermal conductivity of the matrix. The simulation results show that the impact of dispersed carbon nanomaterials on thermal enhancement of the composites is less significant than that of metal foams.
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| 16. |
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| 17. |
- Zhang, Yan, et al.
(author)
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MDS Investigation on the Heat Transfer Properties of CNT Micro-Channel Cooler
- 2010
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In: IEEE CPMT Electronics System Integration Conference (ESTC). - 9781424485536
-
Conference paper (other academic/artistic)abstract
- With the continuously increasing packaging density, the corresponding techniques for heat dissipation are vital to high performance components. During the system operation, the heat generated by components must be efficiently transferred outside of the electronic package. To meet the heat removal requirement of the electronic devices with a high power, several liquid cooling schemes have been suggested, among which the micro-channel cooler have gained the most attention. Simultaneously, the carbon nanotube (CNT) has attracted a significant interest in the material properties and exploratory application. Some studies have been recently conducted to evaluate the thermal performance of the CNTs and their applicability for heat removal in integrated circuit (IC) devices. By utilizing the adhesive transfer process to form the CNT bundles as the fins during the micro-channel development, the devices can be immune from the high temperature required by the CNT growth process. In the present paper, the interface heat transfer in the CNT-based micro-channel cooler has been investigated. The thermal resistances introduced by the interface between the CNT and the epoxy due to adhesive transfer and the interface between the CNT and water have been simulated by molecular dynamics simulation (MDS) method. And the thermal resistance at the interface between the CNT and the epoxy is about 1.0-1.5 × 10 -8 Km 2 /W. The obtained MDS results are likely to provide the microscopic understanding of the thermal performance of the CNT micro-channel cooler as well as provide references to the macroscopic evaluation of the thermal efficiency for the micro-channel cooler design and optimization.
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| 18. |
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| 19. |
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