| 1. |
- Cai, Yumeng, et al.
(author)
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Characterization of Gate-Oxide Degradation Location for SiC MOSFETs Based on the Split C-V Method Under Bias Temperature Instability Conditions
- 2023
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In: IEEE transactions on power electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 0885-8993 .- 1941-0107. ; 38:5, s. 6081-6093
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Journal article (peer-reviewed)abstract
- Gate-oxide degradation has been one of the major reliability challenges of SiC mosfets. Comprehensive and accurate localization of gate-oxide degradation under bias temperature instability (BTI) conditions is important to improve the device reliability. The split C-V [gate-source capacitance C-GS (v(G)) and gate-drain capacitance C-GD (v(G))] method is proposed in this article to locate gate-oxide degradation. Moreover, a BTI automated characterization system integrated I-V and split C-V test is presented. The effect of gate-oxide degradation on threshold voltage and split C-V under dc and ac BTI conditions is investigated and the degradation location is analyzed. Furthermore, the degradation simulation is conducted with technology computer aided design (TCAD) to reveal the mechanism. The results show that the different parts of split C-V can characterize degradation location, the type, and energy level of traps. The acceptor traps near valence band and donor traps near conduction band cause gate-oxide degradation above the channel and junction field effect transistor (JFET) region in positive bias temperature instability (PBTI) and Negative Bias Temperature Instability (NBTI), respectively. In ac BTI, the gate-oxide degradation at the channel region is independent of v(G) polarity, while the opposite is true above JFET region. These findings help to improve the long-term operation reliability of gate oxide from the perspective of chip design and application.
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| 2. |
- Chen, Kaixuan, et al.
(author)
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Mapping formation mechanisms and transformation regimes of multiple Fe precipitates in Cu-Fe-Co alloy during casting process
- 2024
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In: Scripta Materialia. - : Elsevier BV. - 1359-6462 .- 1872-8456. ; 246
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Journal article (peer-reviewed)abstract
- Precipitate features including size, morphology, crystal structure, etc., are important parameters determining the performance of precipitate-strengthened alloys. Multiple Fe precipitates were identified in as-cast Cu alloys exhibiting the distinct features, which dramatically influence mechanical properties. However, a complete understanding of precipitation behaviors of Fe particles during casting, in terms of both microscopic kinetics and thermodynamics, remains experimentally challenging. Here, we report the combined implementation of transmission electron microscopy, Thermo-Calc calculations and First-principles calculations to map mechanisms and growth regimes of Fe precipitation in a Cu-Fe-Co system. Our analyses support the idea that to understand the microstructural evolution in the system, both thermodynamic and kinetic arguments must be taken into account. Then, using our multi-approach strategy, the complete picture of the formation and transformation of Fe precipitates is proposed. This work is vital to promote microstructural design for Cu-Fe(-Co) systems, and sheds new insights into understanding of intricate precipitation in alloys.
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| 3. |
- Chen, Ziqing, et al.
(author)
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Phosphodiesterase 4A confers resistance to PGE2-mediated suppression in CD25(+)/CD54(+) NK cells
- 2021
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In: EMBO Reports. - : EMBO Press. - 1469-221X .- 1469-3178. ; 22:3
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Journal article (peer-reviewed)abstract
- Inadequate persistence of tumor-infiltrating natural killer (NK) cells is associated with poor prognosis in cancer patients. The solid tumor microenvironment is characterized by the presence of immunosuppressive factors, including prostaglandin E2 (PGE2), that limit NK cell persistence. Here, we investigate if the modulation of the cytokine environment in lung cancer with IL-2 or IL-15 renders NK cells resistant to suppression by PGE2. Analyzing Cancer Genome Atlas (TCGA) data, we found that high NK cell gene signatures correlate with significantly improved overall survival in patients with high levels of the prostaglandin E synthase (PTGES). In vitro, IL-15, in contrast to IL-2, enriches for CD25(+)/CD54(+) NK cells with superior mTOR activity and increased expression of the cAMP hydrolyzing enzyme phosphodiesterase 4A (PDE4A). Consequently, this distinct population of NK cells maintains their function in the presence of PGE2 and shows an increased ability to infiltrate lung adenocarcinoma tumors in vitro and in vivo. Thus, strategies to enrich CD25(+)/CD54(+) NK cells for adoptive cell therapy should be considered.
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| 4. |
- Gao, Qingwei, et al.
(author)
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Preliminary study on mechanism of confined mass transfer and separation : "secondary confinement" effect of interfacial adsorption layer [限域传质分离机制初探:界面吸附层的"二次限域"效应]
- 2020
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In: Huagong Xuebao/CIESC Journal. - : Materials China. - 0438-1157. ; 71:10, s. 4688-4695
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Journal article (peer-reviewed)abstract
- The confined mass transfer separation membrane is mainly for the high-precision separation process at the molecular/ion level, which is of great significance to solve the application needs of CO2 separation, azeotrope separation, lithium extraction from salt lake, desalination of seawater and so on. However, at present, the research of the confined mass transfer mechanism of this kind of membrane is lagging behind, and the theoretical models of confined mass transfer are lacking, which can no longer meet the needs of the rapid development of materials and chemical engineering. From the perspective of meso-science, the abnormal phenomenon of high flux and high selectivity of the confined mass transfer separation membrane is considered, that is, breaking through the trade-off effect, which is governed by compromise-in-competition between the selectivity mechanism and the flux mechanism. It is found that the fluid molecules will preferentially adsorb at the interface and form a stable adsorption layer. Based on this, the hypothesis of "secondary confinement" is put forward, that is, the surface induced new solid-like interface will have confinement effect on the intermediate fluid again. By comparing the pore size and the secondary confined size of the confined mass transfer separation membrane, the selective mechanism of the secondary confinement is further confirmed, and the quantitative prediction of the membrane flux and selectivity is preliminarily explored by combining the selective mechanism and the flux model, which may provide a theoretical basis for the precise construction of the limited area mass transfer membrane. © 2020, Chemical Industry Press Co., Ltd. All right reserved.
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| 5. |
- Lin, Ci, et al.
(author)
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Direct Band Gap in Multilayer Transition Metal Dichalcogenide Nanoscrolls with Enhanced Photoluminescence
- 2022
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In: ACS Materials Letters. - : American Chemical Society (ACS). - 2639-4979. ; 4:8, s. 1547-1555
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Journal article (peer-reviewed)abstract
- A direct band gap that solely exists in monolayer semiconducting transition metal dichalcogenides (TMDs) endows strong photoluminescence (PL) features, whereas multilayer TMD structures exhibit quenched PL due to the direct-to-indirect band gap transition. We demonstrate multi-layer TMD (such as MoS2 and WS2) nanoscrolls with a preserved direct band gap fabricated by an effective and facile method of solvent-driven self-assembly. The resultant multi-layer nanoscrolls, exhibiting up to 11 times higher PL intensity than the remanent monolayer, are carefully characterized using PL spectroscopy. Significantly enlarged interlayer distances and modulated interlayer coupling in the fabricated nanostructures are unveiled by cross-sectional scanning transmission electron microscopy, atomic force microscopy, and Raman spectroscopy. The preservation of direct band gap features is further evidenced by density functional theory calculations using the simplified bilayer model with an experimentally obtained 15 & ANGS; interlayer distance. The modulation of the PL intensity as an indicator of the band gap crossover in the TMD nanoscrolls is demonstrated by removing the acetone molecules trapped inside the interlayer space. The general applicability of the method presents an opportunity for large-scale fabrication of a plethora of multilayer TMD nanoscrolls with direct band gaps.
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| 6. |
- Sun, Zhuoyu, et al.
(author)
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Gestational diabetes mellitus and risks of gynecologic cancers : Results from a nationwide Swedish twin study
- 2021
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In: Gynecologic Oncology. - : Elsevier BV. - 0090-8258 .- 1095-6859. ; 162:1, s. 142-147
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Journal article (peer-reviewed)abstract
- Background: Type 2 diabetes has been associated with increased risk of gynecologic cancers, yet the effect of gestational diabetes mellitus (GDM) on gynecologic cancers is unclear.Objectives: To examine associations between GDM history and subsequent gynecologic cancers in parous women, and to explore whether gestational hypertension (GH) plays a role in the associations.Study design: The population-based cohort study included 15,941 individuals from the Swedish Twin Registry. The history of GDM and GH was ascertained based on self-reports. Incident cases of gynecologic cancers (including cancers of the cervix, uterus, ovaries and other female genitalia) were obtained from the National Patients Registry and the Swedish Cancer Registry. Generalized estimating equation models were applied to analyze associations between GDM and gynecologic cancers. Stratified analysis was used to explore whether associations between GDM and gynecologic cancers differed by GH. Additive and multiplicative interactions were calculated between GDM and GH.Results: Of all participants, 350 (2.2%) had GDM, and 1762 (11.1%) had incident gynecologic cancers. No statistically significant associations were found between GDM and risks of any gynecologic cancers. However, GDM was associated with an increased risk of ovarian cancer (OR = 5.29, 95% CI: 1.63–17.19) in women with GH. Interactions between GDM and GH were observed on the additive scale (Attributable proportion due to interaction: 0.86, 95% CI 0.42–1.30, P < 0.001).Conclusions: The associations between GDM and risks of gynecologic cancers were not evident, but the effect of GDM on the risk of ovarian cancer was modified by GH. Further validation in larger cohorts is warranted.
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| 7. |
- van de Weijer, Jeroen, et al.
(author)
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Gender identification in Chinese names
- 2020
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In: Lingua. - : Elsevier BV. - 0024-3841. ; 234
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Journal article (peer-reviewed)abstract
- In this paper we discuss a number of factors that bear on the question if a Chinese given name is more likely to refer to a female or a male. In some cases this can be determined (with some degree of confidence) – in others it cannot. We identify the relevant factors as 1) gender-identifying characters or radicals; 2) sound symbolism and 3) reduplication. We consider the relations between these factors, and test our predictions in a psycholinguistic experiment with native speakers, for both written and spoken Chinese.
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| 8. |
- Yuan, Yuan, et al.
(author)
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Comprehensive molecular characterization of mitochondrial genomes in human cancers
- 2020
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In: Nature Genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 52:3, s. 342-352
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Journal article (peer-reviewed)abstract
- Mitochondria are essential cellular organelles that play critical roles in cancer. Here, as part of the International Cancer Genome Consortium/The Cancer Genome Atlas Pan-Cancer Analysis of Whole Genomes Consortium, which aggregated whole-genome sequencing data from 2,658 cancers across 38 tumor types, we performed a multidimensional, integrated characterization of mitochondrial genomes and related RNA sequencing data. Our analysis presents the most definitive mutational landscape of mitochondrial genomes and identifies several hypermutated cases. Truncating mutations are markedly enriched in kidney, colorectal and thyroid cancers, suggesting oncogenic effects with the activation of signaling pathways. We find frequent somatic nuclear transfers of mitochondrial DNA, some of which disrupt therapeutic target genes. Mitochondrial copy number varies greatly within and across cancers and correlates with clinical variables. Co-expression analysis highlights the function of mitochondrial genes in oxidative phosphorylation, DNA repair and the cell cycle, and shows their connections with clinically actionable genes. Our study lays a foundation for translating mitochondrial biology into clinical applications.
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| 9. |
- Zhang, Yumeng, et al.
(author)
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Effects of ionic hydration and hydrogen bonding on flow resistance of ionic aqueous solutions confined in molybdenum disulfide nanoslits : Insights from molecular dynamics simulations
- 2019
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In: Fluid Phase Equilibria. - : Elsevier. - 0378-3812 .- 1879-0224. ; 489, s. 23-29
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Journal article (peer-reviewed)abstract
- Single-layer molybdenum disulfide (MoS2) is a novel two-dimensional material that has attracted considerable attention because of its excellent properties. In this work, molecular dynamics simulations were performed to investigate the effect of different kinds of alkali metal ions (Li+, Na+, and K+) on the flow resistance of ionic aqueous solutions confined in MoS2 nanoslits under shearing. Three slit widths (i.e. 1.2, 1.6, and 2.0 nm) were investigated. Simulation results showed that the friction coefficient followed the order of K+ < Na+ < Li+. The friction coefficient decreased with the increasing of slit width. Unique confined spatial distributions of different types of ionic aqueous solutions led to different confined ionic hydrations for different cations. These differences lead to different orientations of surrounding water molecules and then form different hydrogen bond (HB) networks. The friction coefficient was greatly dependent on the number of HBs per water; i.e., the larger the number of HBs formed, the lower was the flow resistance.
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| 10. |
- Zhang, Yumeng, et al.
(author)
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Molecular insight into flow resistance of choline chloride/urea confined in ionic model nanoslits
- 2021
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In: Fluid Phase Equilibria. - : Elsevier. - 0378-3812 .- 1879-0224. ; 533
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Journal article (peer-reviewed)abstract
- Choline chloride/urea (1:2) is the most widely used deep eutectic solvent, which has attracted much attention due to its excellent advantages of low cost, environment friendly and easy synthesis. In this work, nanofriction-based molecular dynamics simulations were performed to investigate the effect of interfacial hydrophilicity on the flow resistance of Choline chloride/urea (1:2) confined in ionic model nanoslits. Simulation results showed that the flow resistance of the choline chloride/urea system increases with the increasing interfacial hydrophilicity. Urea molecules form a preferential adsorption layer on the wall. As the interfacial hydrophilicity increases, the number of urea molecules in the interfacial adsorption layer increased, whereas the stability decreased. Unique confined spatial distributions of urea molecules greatly contribute to ionic association between choline cations and chloride anions. Furthermore, with the increase of interfacial hydrophilicity, orientation distributions of urea molecules in the adsorption layer are more orderly, then causing a decrease in the average hydrogen bond number (NHB) of urea molecules. Moreover, the more the NHB of urea molecules, the better is the stability in the interfacial adsorption layer, which in turn results in less flow resistance.
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