检索结果-南通市图书馆

Control of GaN inverted pyramids growth on c-plane patterned sapphire substrates

在线全文

学校读者我要写书评

暂无评论

Journal of Semiconductors 2024年第6期45卷 92-96页

作者： Luming Yu xun Wang Zhibiao Hao Yi Luo Changzheng Sun Bing Xiong Yanjun Han Jian Wang Hongtao li lin Gan Lai Wang Beijing National Research Center for Information Science and Technology Department of Electronic EngineeringTsinghua UniversityBei-jing 100084China Center for Flexible Electronics Technology Tsinghua UniversityBeijing 100084China

Growth of gallium nitride(GaN)inverted pyramids on c-plane sapphire substrates is benefit for fabricating novel devices as it forms the semipolar *** this work,GaN inverted pyramids are directly grown on c-plane patterned sapphire substrates(PSS)by metal organic vapor phase epitaxy(MOVPE).The influences of growth conditions on the surface morphol-ogy are experimentally studied and explained by Wulff *** competition of growth rate among{0001},{1011},and{1122}facets results in the various surface morphologies of GaN.A higher growth temperature of 985 ℃ and a lowerⅤ/Ⅲratio of 25 can expand the area of{}facets in GaN inverted *** the other hand,GaN inverted pyramids with almost pure{}facets are obtained by using a lower growth temperature of 930℃,a higherⅤ/Ⅲratio of 100,and PSS with pattern arrangement perpendicular to the substrate primary flat.

关键词： inverted pyramids GaN MOVPE crystal growth competition model

Modeling drug-induced mitochondrial toxicity with human primary cardiomyocytes

在线全文

学校读者我要写书评

暂无评论

Science China(life Sciences) 2024年第2期67卷 301-319页

作者： Xiaoli Tang Hong liu Rongjia Rao Yafei Huang Mengqi Dong Miaomiao Xu Shanshan Feng xun Shi li Wang Zengwu Wang Bingying Zhou State Key Laboratory of Cardiovascular Disease Fuwai HospitalNational Center for Cardiovascular DiseasesChinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100037China Department of Epidemiology Cardiovascular Institute and Fuwai HospitalChinese Academy of Medical Science&Peking Union Medical CollegeBeijing 100037China Shenzhen Key Laboratory of Cardiovascular Disease Fuwai Hospital Chinese Academy of Medical SciencesShenzhenShenzhen 518020China

Mitochondrial toxicity induced by therapeutic drugs is a major contributor for cardiotoxicity,posing a serious threat to pharmaceutical industries and patients’***,mitochondrial toxicity testing is not incorporated into routine cardiac safety screening *** accurately model native human cardiomyocytes,we comprehensively evaluated mitochondrial responses of adult human primary cardiomyocytes(h PCMs)to a nucleoside analog,remdesivir(RDV).Comparison of their response to human pluripotent stem cell-derived cardiomyocytes revealed that the latter utilized a mitophagy-based mitochondrial recovery response that was absent in h ***,action potential duration was elongated in h PCMs,reflecting clinical incidences of RDV-induced QT *** a screen for mitochondrial protectants,we identified mitochondrial ROS as a primary mediator of RDV-induced *** study demonstrates the utility of h PCMs in the detection of clinically relevant cardiac toxicities,and offers a framework for h PCM-based high-throughput screening of cardioprotective agents.

关键词： remdesivir mitochondrial toxicity cardiotoxicity human primary cardiomyocytes high-throughput screening

Roughness characterization and shearing dislocation failure for rock-backfill interface

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1167-1176页

作者： Meifeng Cai Zhilou Feng Qifeng Guo Xiong Yin Minghui Ma xun Xi Key Laboratory of High-Efficient Mine and Safety of Metal Mines of Ministry of Education Beijing 100083China Key Laboratory of Urban and Underground Space Engineering University of Science and Technology BeijingBeijing 100083China Shandong Gold Group Co LtdJinan 250102China

Shearing dislocation is a common failure type for rock–backfill interfaces because of backfill sedimentation and rock strata movement in backfill mining *** paper designed a test method for rock–backfill shearing *** digital image techno-logy and three-dimensional(3D)laser morphology scanning techniques,a set of 3D models with rough joint surfaces was ***,the mechanical behavior of rock–backfill shearing dislocation was investigated using a direct shear *** effects of interface roughness on the shear–displacement curve and failure characteristics of rock–backfill specimens were *** 3D fractal dimen-sion,profile line joint roughness coefficient(JRC),profile line two-dimensional fractal dimension,and the surface curvature of the frac-tures were *** correlation characterization of surface roughness was then analyzed,and the shear strength could be measured and calculated using *** results showed the following:there were three failure threshold value points in rock–backfill shearing dis-location:30%–50%displacement before the peak,70%–90%displacement before the peak,and 100%displacement before the peak to post-peak,which could be a sign for rock–backfill shearing dislocation *** surface JRC could be used to judge the rock–backfill shearing dislocation failure,including post-peak sliding,uniform variations,and gradient change,corresponding to rock–backfill disloca-tion failure on the field *** research reveals the damage mechanism for rock–backfill complexes based on the free joint surface,fills the gap of existing shearing theoretical systems for isomerism complexes,and provides a theoretical basis for the prevention and control of possible disasters in backfill mining.

关键词： rock–backfill roughness correlation characterization shearing dislocation interface failure

Impact of fluorine on crystal-melt separation in high-silica magma: Insights from muscovite in the Ramba leucogranite of Tethyan Himalaya

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2024年

作者： li-Ran Chen Wang-Chun Xu lian-xun Wang Hong-Fei Zhang Wuhan State Key Laboratory of Geological Processes and Mineral Resources， and School of Earth Sciences， China University of Geosciences

The process of crystal-melt separation in the high-silica magmatic mush is still a subject of debate. To explore the process， we conducted a detailed study of Late Miocene leucogranites (SiO2＞70 wt.%) in the Ramba Dome of the Tethyan Himalaya， focusing on the genesis and fluorine content of muscovite. The Ramba leucogranites consist of two-mica granite with minor garnet-bearing granite. Large and euhedral muscovites are found in both types of granite exhibiting different geochemical features. The muscovites from the two-mica granites exhibit lower F (mean value: ～0.41–0.43 wt.%)， FeO (mean value: ～1.75–1.81 wt.%)， but higher TiO2(mean value: ～0.61–0.73 wt.%) contents compared to those from the garnet-bearing granites (mean F value: ～0.72%; mean FeO value: 2.48 wt.%; mean TiO2value: ～0.23 wt.%). According to geochemical criteria， we categorized the muscovites from the two-mica granite as two groups: (1) crystallized from the early magma， and (2) formed from interstitial residual melt. In comparison， the muscovite from the garnet-bearing granite was likely crystallized from residual melt extracted from the same magmatic reservoir which underwent a higher degree of evolution. Accordingly， the two-mica granite represents the residual crystal mush consisting of early crystals crystallized from magma and trapped interstitial residual melt， while the garnet-bearing granite represents the aggregation of extracted residual melt. We examined the possibility of crystal-melt separation by estimating the variation of fluorine content and viscosity between the early magma and residual melt. Our results indicate a notable disparity in fluorine content between the residual melt (mean value: ～4364 ppm) and the early magma (mean value: ～2033 ppm). As a result， the estimated viscosity experiences a reduction from 106.52Pa s for the early magma to 105.87Pa s for the residual melt. The fluorine enrichment could have played a critical role in decreasing melt viscosity and initiating crys

关键词：

Microsnoop: A generalist tool for microscopy image representation

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

The Innovation 2024年第1期5卷 109-117页

作者： Dejin xun Rui Wang Xingcai Zhang Yi Wang Pharmaceutical Informatics Institute College of Pharmaceutical SciencesZhejiang UniversityHangzhou 310058China State Key Lab of Computer-Aided Design&Computer Graphics Zhejiang UniversityHangzhou 310058China John A.Paulson School of Engineering and Applied Sciences Harvard UniversityCambridgeMA 02138USA Innovation Institute for Artificial Intelligence in Medicine of Zhejiang University Hangzhou 310018China National Key Laboratory of Chinese Medicine Modernization Innovation Center of Yangtze River DeltaZhejiang UniversityJiaxing 314100China

Accurate profiling of microscopy images from small scale to high throughput is an essential procedure in basic and applied biological ***,we present Microsnoop,a novel deep learning–based representation tool trained on large-scale microscopy images using masked self-supervised *** can process various complex and heterogeneous images,and we classified images into three categories:single-cell,full-field,and batch-experiment *** benchmark study on 10 high-quality evaluation datasets,containing over 2,230,000 images,demonstrated Microsnoop’s robust and state-ofthe-art microscopy image representation ability,surpassing existing generalist and even several custom *** can be integrated with other pipelines to perform tasks such as superresolution histopathology image and multimodal ***,Microsnoop can be adapted to various hardware and can be easily deployed on local or cloud computing *** will regularly retrain and reevaluate the model using communitycontributed data to consistently improve Microsnoop.

关键词： hardware image representation

MarR family proteins sense sulfane sulfur in bacteria

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

mlife 2024年第2期3卷 231-239页

作者： Guanhua Xuan Luying xun Yongzhen Xia State Key Laboratory of Microbial Technology Shandong UniversityQingdaoChina State Key Laboratory of Marine Food Processing&Safety Control Ocean University of ChinaQingdaoChina School of Molecular Biosciences Washington State UniversityPullmanWashingtonUSA

Members of the multiple antibiotic resistance regulator(MarR)protein family are ubiquitous in bacteria and play critical roles in regulating cellular metabolism and antibiotic *** family proteins function as repressors,and their interactions with modulators induce the expression of controlled *** previously characterized modulators are insufficient to explain the activities of certain MarR family ***,recently,several MarR family proteins have been reported to sense sulfane sulfur,including zero-valent sulfur,persulfide(R-SSH),and polysulfide(R-SnH,n≥2).Sulfane sulfur is a common cellular component in bacteria whose levels vary during bacterial *** changing levels of sulfane sulfur affect the expression of many MarR-controlled *** sulfur reacts with the cysteine thiols of MarR family proteins,causing the formation of protein thiol persulfide,disulfide bonds,and other *** MarR family proteins that respond to reactive oxygen species(ROS)also sense sulfane sulfur,as both sulfane sulfur and ROS induce the formation of disulfide *** review focused on MarR family proteins that sense sulfane ***,the sensing mechanisms reviewed here may also apply to other proteins that detect sulfane sulfur,which is emerging as a modulator of gene regulation.

关键词： cysteine thiols disulfide bond MarR protein family ROS sulfane sulfur

Hydromassage of macular hole edges for large and persistent full-thickness macular holes

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2024年第3期17卷 551-557页

作者： Yi Cai Wen-Bo liu Duo Wei xun Deng Xiao-Xin li Ming-Wei Zhao Xuan Shi Jian-Hong liang Department of Ophthalmology Peking University People’s HospitalBeijing 100044China Eye Diseases and Optometry Institute Beijing 100044China Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases Beijing 100044China College of Optometry Peking University Health Science CenterBeijing 100044China Xiamen Eye Center of Xiamen University Xiamen 361102Fujian ProvinceChina Department of Ophthalmology the Second Hospital of Lanzhou UniversityLanzhou 730030Gansu ProvinceChina

●AIM:To introduce the macular hole(MH)hydromassage technique as a potentially beneficial approach for the treatment of large or persistent MH.●METHODS:This retrospective observational case series comprised 16 consecutive patients(17 eyes)diagnosed with *** criteria involved a hole aperture diameter larger than 600μm or the presence of an unclosed MH larger than 600μm following the previous *** MH repair procedures were administered in all cases,involving the manipulation and aspiration of the hole margin through the application of water flow with a soft-tip flute needle.A comprehensive assessment was conducted for each case before and after surgery,and optical coherence tomography(OCT)images were captured at every follow-up point.●RESULTS:The mean preoperative aperture diameter was 747±156μm(range 611-1180μm),with a mean base diameter of 1390±435μm(range 578-2220μm).Following surgery,all cases achieved complete anatomical closure of MH,with 13 cases(76.5%)exhibiting type 1 closure and 4 cases(23.5%)demonstrating type 2 *** significant differences were observed in the preoperative OCT variables between the two closure *** with type 1 closure showed a significantly improved visual acuity(0.70±0.10,range 0.50-0.80)compared to those with type 2 closure(0.90±0.12,range 0.80-1.00,P=0.014).●CONCLUSION:The MH hydromassage technique demonstrates promising results,achieving acceptable closure rates in cases of large or persistent *** technique may serve as an effective adjunctive maneuver during challenging MH surgery.

关键词： macular hole large macular hole persistent macular hole optical coherence tomography surgical technique hydromassage

A calibration and compensation method for an industrial robot with high accuracy harmonic reducers

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2024年第3期67卷 725-739页

作者： ZHAO YiYang liU xun CAO JiaBin liU JinYu XU Yan YAN WeiXin School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China College of Computer and Control Engineering Northeast Forestry UniversityHarbin 150040China

Industrial serial robots need high stiffness to keep absolute pose accuracy and meet the requirements in practical applications. However, the weak stiffness feature of robot joints and the payloads affected on robot end-effector, which will also increase the pose error of robot. Especially, the existing calibration methods often consider under no-payload condition without discussing the payload state. In this paper, we report a new industrial serial robot composed by a new harmonic reducer: Model-Y, based on high accuracy and high stiffness, and a kinematic parameter calibration algorithm which is based on a harmonic reducer forcedeformation model. To decrease the accuracy effects of payload, an iterative calibration method for kinematic parameters with payload situation was proposed. Simulation and experiments are conducted to verify the effectiveness of the proposed calibration method using the self-developed industrial serial robot. The results show a remarkably improved accuracy in absolute position and orientation with the robot's payload range. The position mean error has 70% decreased to 0.1 mm and the orientation mean error diminished to less than 0.01° after calibration with compensation. Additionally, online linear and circular tests are carried out to evaluate the position error of the robot during large-scale spatial and low-speed continuous movement. The accuracy is consistent with the previous calibration results, indicating the effectiveness and advantages of the proposed strategy in this article.

关键词： industrial serial robot Model-Y harmonic calibration stiffness model online compensation

Robust video question answering via contrastive cross-modality representation learning

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2024年第10期67卷 211-226页

作者： xun YANG Jianming ZENG Dan GUO Shanshan WANG Jianfeng DONG Meng WANG School of Information Science and Technology University of Science and Technology of China Institute of Artificial Intelligence Hefei Comprehensive National Science Center School of Computer Science and Information Engineering Hefei University of Technology Institutes of Physical Science and Information Technology Anhui University School of Computer Science and Technology Zhejiang Gongshang University

Video question answering(VideoQA) is a challenging yet important task that requires a joint understanding of low-level video content and high-level textual semantics. Despite the promising progress of existing efforts, recent studies revealed that current VideoQA models mostly tend to over-rely on the superficial correlations rooted in the dataset bias while overlooking the key video content, thus leading to unreliable results. Effectively understanding and modeling the temporal and semantic characteristics of a given video for robust VideoQA is crucial but, to our knowledge, has not been well investigated. To fill the research gap, we propose a robust VideoQA framework that can effectively model the cross-modality fusion and enforce the model to focus on the temporal and global content of videos when making a QA decision instead of exploiting the shortcuts in datasets. Specifically, we design a self-supervised contrastive learning objective to contrast the positive and negative pairs of multimodal input, where the fused representation of the original multimodal input is enforced to be closer to that of the intervened input based on video perturbation. We expect the fused representation to focus more on the global context of videos rather than some static keyframes. Moreover, we introduce an effective temporal order regularization to enforce the inherent sequential structure of videos for video representation. We also design a Kullback-Leibler divergence-based perturbation invariance regularization of the predicted answer distribution to improve the robustness of the model against temporal content perturbation of videos. Our method is model-agnostic and can be easily compatible with various VideoQA backbones. Extensive experimental results and analyses on several public datasets show the advantage of our method over the state-of-the-art methods in terms of both accuracy and robustness.

关键词： video question answering cross-modality fusion contrastive learning cross-media reasoning