检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

功率器件IGBT模块模态分析与实验验证

电力电子技术 2024年第7期58卷 105-108页

作者：王浩洁刘东静朱娟娟马永翔陕西理工大学电气工程学院陕西汉中723001 桂林电子科技大学机电工程学院广西桂林541004

针对绝缘栅双极型晶体管(IGBT)功率器件在振动环境下的可靠性问题,基于模态分析方法对IGBT模块的动态特性进行研究分析。通过有限元软件建立用于模态分析的功率器件IGBT模块模型,利用模态分析获取模块在不同约束下的前6阶固有频率及其... 详细信息

针对绝缘栅双极型晶体管(IGBT)功率器件在振动环境下的可靠性问题,基于模态分析方法对IGBT模块的动态特性进行研究分析。通过有限元软件建立用于模态分析的功率器件IGBT模块模型,利用模态分析获取模块在不同约束下的前6阶固有频率及其相应阵型,结合激振实验评估模型准确性,对比分析各实验与模拟结果出现差异原因,并提出规避共振现象的改进措施,进而提升模块的使用寿命。该研究结果对功率器件IGBT模块的振动分析提供参考,同时为模块结构的设计提供理论依据。

关键词：晶体管功率器件模态分析可靠性

Miniaturized power detection module operating in millimeter wave band

在线全文

学校读者我要写书评

暂无评论

Journal of Electronic Science and Technology 2024年第2期22卷 69-76页

作者： xiang Zhou Zhi-yong Zhong School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu611731China

The miniaturized broadband detection module can be embedded into the microwave application system such as the front end of the transmitter to detect the power or other parameters in real *** is highly prospective in military and scientific *** this paper,a broadband power detection module operating at 26.5 GHz-40.0 GHz is designed by using low-barrier Schottky diode as the detector and a comparator for threshold *** module can dynamically detect the power range between-10 dBm and 10 dBm with the detection accuracy of 0.1 ***,the temperature compensation circuit is also applied to improve the measurement *** a result,the resulted error low to±1 dB in the temperature range of -55℃ to +85℃ is *** designed module is encapsulated by a Kovar alloy with a small volume of 9 mm×6 mm×3 *** endows the designed module the advantages of small size,easy integration,and low cost,and even it is applicable to high-reliability environments such as satellites.

关键词： Diode Miniaturization Power detection Temperature compensation

A Parameter Adaptive Method for Image Smoothing

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2024年第4期29卷 1138-1151页

作者： Suwei Wang xiang ma Xuemei Li School of Computer Science and Technology Shandong UniversityJinan 250101China School of Software Shandong UniversityJinan 250101China

Edge is the key information in the process of image smoothing. Some edges, especially the weak edges, are difficult to maintain, which result in the local area being over-smoothed. For the protection of weak edges, we propose an image smoothing algorithm based on global sparse structure and parameter adaptation. The algorithm decomposes the image into high frequency and low frequency part based on global sparse structure. The low frequency part contains less texture information which is relatively easy to smoothen. The high frequency part is more sensitive to edge information so it is more suitable for the selection of smoothing parameters. To reduce the computational complexity and improve the effect, we propose a bicubic polynomial fitting method to fit all the sample values into a surface. Finally, we use Alternating Direction Method of Multipliers (ADMM) to unify the whole algorithm and obtain the smoothed results by iterative optimization. Compared with traditional methods and deep learning methods, as well as the application tasks of edge extraction, image abstraction, pseudo-boundary removal, and image enhancement, it shows that our algorithm can preserve the local weak edge of the image more effectively, and the visual effect of smoothed results is better.

关键词： image smoothing parameter adaptation bicubic interpolation polynomial fitting

Synthesis of Biaryl Ferrocenyl 2-Propene-1-ones

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

有机化学 2003年第Z1期23卷 361-362页

作者： SONG Qing-Bao WU Xiao-Li SHEN Tian-Hua YANG Shang-Dong QIANG Gen-Rong WANG yong-Qiang ma yong-xiang College of Chemical Engineering Zhejiang University of Technology Hangzhou 310014 National Laboratory of Applied Organic Chemistry Lanzhou University Lanzhou 730000

Last two decades, molecular-based second-order nonlinear optical (NLO) chromo-phores[1,2] have attracted much attention because of their potential applications in emerging opto-electronic technologies. These efforts have mainly focused on organic systems. More recently, organometallic molecules have been investigated as well. In comparison to common organic molecules, they offer a large variety of novel structures. The possibility of high environ mental stability, and diversity of turnable electronic behaviors by virtue of the coordinated metal center of which might bring about NLO materials with unique characteristics such as magnetic and electro-chemical properties.……

关键词： nonlinear optical organic systems NLO materials

Potential role of hippocampal neurogenesis in spinal cord injury induced post-trauma depression

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2024年第10期19卷 2144-2156页

作者： Ying ma Yue Qiao xiang Gao Spinal Cord and Brain Injury Research Group Stark Neuroscience Research InstituteIndianapolisINUSA Department of Neurological Surgery Indiana University School of MedicineIndianapolisINUSA Department of Neurology Shengjing Hospital of China Medical UniversityShenyangLiaoning ProvinceChina

It has been reported both in clinic and rodent models that beyond spinal cord injury directly induced symptoms, such as paralysis, neuropathic pain, bladder/bowel dysfunction, and loss of sexual function, there are a variety of secondary complications, including memory loss, cognitive decline, depression, and Alzheimer's disease. The largescale longitudinal population-based studies indicate that post-trauma depression is highly prevalent in spinal cord injury patients. Yet, few basic studies have been conducted to address the potential molecular mechanisms. One of possible factors underlying the depression is the reduction of adult hippocampal neurogenesis which may come from less physical activity, social isolation, chronic pain, and elevated neuroinflammation after spinal cord injury. However, there is no clear consensus yet. In this review, we will first summarize the alteration of hippocampal neurogenesis post-spinal cord injury. Then, we will discuss possible mechanisms underlie this important spinal cord injury consequence. Finally, we will outline the potential therapeutic options aimed at enhancing hippocampal neurogenesis to ameliorate depression.

关键词： antidepressants chronic pain depression exercise hippocampal neurogenesis inflammation inhibition neuroinflammation physical activity deficits social isolation spinal cord injury

Lifetime-tunable circularly polarized luminescent system based on triplet-to-singlet Förster resonance energy transfer

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第9期67卷 2918-2922页

作者： Zhenyi He Zizhao Huang xiang ma Key Laboratory for Advanced materials and Feringa Nobel Prize Scientist Joint Research Center Institute of Fine ChemicalsSchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China

Circularly polarized luminescence(CPL)materials have received widespread attention due to their remarkable performance and broad ***,current CPL material research primarily focuses on tunable color,intensity,and *** CPL with adjustable lifetime remains a significant ***,a series of CPL polymeric materials with tunable lifetime were obtained by employing phosphorescent terephthalic acid and chiral organic small molecule R/S-BNAF(a luminescent binaphthol derivative)to copolymerize with acrylamide in different *** was verified that this performance results from the different energy transfer efficiency between luminophores with varying ratios of the monomers for *** strategy to realize CPL with tunable lifetime by modulating the energy transfer efficiency will provide a new perspective to broaden the applications of CPL materials.

关键词： circularly polarized luminescence tunable lifetime Förster resonance energy transfer room temperature phosphorescence

Arbitrary topological charge vortex beams from carbon dots random lasers

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第8期43卷 3844-3853页

作者： xiang-Dong Wang Xiao-Bo Mi Jiu-Ru He Feng-Ying ma Jun-Qiao Wang Li Song yong-Qiang Zhang Si-Yu Lu yong-Sheng Hu School of Physics and Microelectronics Zhengzhou UniversityZhengzhou 450001China State Key Laboratory of Reliability and Intelligence of Electrical Equipment and Tianjin Key Laboratory of Electronic materials and Devices School of Electronics and Information EngineeringHebei University of TechnologyTianjin 300401China Green Catalysis Center College of ChemistryZhengzhou UniversityZhengzhou450001China

Vortex beams have attracted great attention due to their promising applications in the fields of high-capacity optical communication,optical micromanipulation,and quantum information ***,we demonstrate vortex beams with flexible control of the topological charge and modes in a carbon dots random laser for the first *** beams with different types,including the Laguerre-Gaussian(LG),Bessel-Gaussian(BG),LG-superposition,and polarized vortex beams with topological charges up to 50,have been successfully ***,vortex beams can be well realized in carbon dots random lasers with different emission wavelengths covering from 465 to 612 *** work would not only enrich the types of vortex laser,especially for solution-processable lasers,but also provide a new route to realizing multicolor and wavelength-tunable vortex lasers.

关键词： Carbon dots Random lasers Vortex beam Topological charge Spatial light modulator

Diversification of interfaces triggered hydrogen storage properties enhancement

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第5期43卷 2324-2330页

作者： Jia-Xin Zhang Xin Ding Rui-Run Chen xiang-Feng ma Wen-Chao Cao yong Zhang Jing-Jie Guo National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China

Dual effects of grain refinement and alloying are achieved and the mechanism of"diverse interfaces reinforcement"for hydrogen storage Mg alloys is first *** interface reinforced Mg-Y-Zn-Al alloy for hydrogen storage is *** work figures out that the adventurous Al-rich phase exhibits an ordered face-centered cubic(FCC)structure with composition of(31±2)at%Y-(28±1)at%Zn-(41±3)at%Al,i.e.,Y_(3)Zn_(3)Al_(4),and an incoherent interface between Y3Zn3Al4phase and Mg substrate is observed.

关键词： hydrogen alloying alloy

Engineering the Interface Between Au Nanoparticles and CoO-Ov to Enhance the Catalytic Performance of 5-Hydroxymethylfurfural(HMF)to 2,5-Dimethylfuran(DMF)

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2024年第1期40卷 47-54页

作者： xiang Shuang GUO yong LIU Xiaohui WANG Yanqin Key Laboratory for Advanced materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering Feringa Nobel Prize Scientist Joint Research CenterResearch Institute of Industrial CatalysisSchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237P.R.China

The interface between Au and support has attracted extensive interest because of its unique catalytic ability for hydrogen activation in catalytic hydrogenation/hydrogenolysis ***,we create the Au-CoO-OV interface in the 1.0%Au/Co3O4-Rod-250 catalyst,which could dissociate H2 via the heterolytic way to yield rich hydride species and achieve excellent catalytic performance in the hydrogenolysis of biomass-derived 5-hydroxymethylfurfural(HMF)to 2,5-dimethylfuran(DMF).The XRD and HRTEM analyses show that Au nanoparticles are uniformly dispersed on CoO-OV surface and in situ DRIFTS spectra show the enhancement of heterolytic dissociation of hydrogen(signals of Au-D and O-D vibration)compared with bare CoO(Co3O4-Rod-250).This work provides insights for fabricating highly active Au-support catalysts for catalytic hydrogenation/hydrogenolysis reactions.

关键词： Au-CoO-OV interface Hydride species Heterolytic dissociation 5-Hydroxymethylfurfural(HMF) 2 5-Dimethylfuran(DMF)