检索结果-南通市图书馆

Highly efficient room temperature phosphorescent liquid crystalline polymer optical waveguides for advanced optoelectronics

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第10期67卷 3450-3457页

作者： Jie Li Yan Guan wei Xia jin-Kang Chen Jiang Huang Yi Chen qi Lin Er-qiang Chen He-Lou Xie Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education and Key Laboratory of Advanced Functional Polymer Materials of CollegesUniversities of Hunan Province and College of ChemistryXiangtan UniversityXiangtan 411105China School of Physics and Optoelectronics Xiangtan UniversityXiangtan 411105China Beijing National Laboratory for Molecular Sciences Key Laboratory of Polymer Chemistry and Physics of Ministry of EducationCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

Active organic optical waveguide materials(OOWMs)incorporating room temperature phosphorescence(RTP)hold significant promise for diverse applications in photonic and optoelectronic *** this potential,realizing active RTP optical waveguides with large-sized ordered structures and minimal light loss remains a formidable *** address this issue,we present a groundbreaking thermoplastic active OOWM with low light loss,leveraging room temperature phosphorescent liquid crystalline polymer(LCP).This innovative material can be easily synthesized through the copolymerization of phosphorescent and liquid crystalline *** resulting RTP copolymer exhibits a nematic liquid crystal phase with a phosphorescence lifetime of approximately 0.15 ms and an afterglow duration of around 1 *** the excellent processability of LCP,we successfully produce meter-scale fibers via melt *** RTP LCP fibers,characterized by a high orientation of mesogens along the fiber axis,demonstrate superior light confinement and efficient light conduction compared to unoriented samples,resulting in a low optical loss coefficient of 0.13 dB/***,the thermal responsiveness of the RTP LCP optical waveguide enables its use as a photo *** pioneering work paves the way for the design of new OOWMs tailored for advanced photonics and optoelectronics devices.

关键词： room temperature phosphorescence liquid crystalline polymer active optical waveguide

在线全文

学校读者我要写书评

暂无评论

超光谱侦察传感器的光电设计与实验分析

光学技术 2007年第2期33卷 193-195页

作者：许强金伟其北京理工大学信息科学技术学院光电工程系

超光谱光电侦察是光学探测经历了单波长、多波段之后发展起来的一个新的阶段,是基于方位和光谱三维信息的新型光电探测技术。在分析景物的光谱-空间特征的基础上,设计了UV/VIS/NIR宽波段范围的超光谱侦察传感器,并进行了成像探测实验,... 详细信息

超光谱光电侦察是光学探测经历了单波长、多波段之后发展起来的一个新的阶段,是基于方位和光谱三维信息的新型光电探测技术。在分析景物的光谱-空间特征的基础上,设计了UV/VIS/NIR宽波段范围的超光谱侦察传感器,并进行了成像探测实验,获得了典型场景和目标的光谱序列图像。对其进行了分析,验证了一种自动目标探测/识别的新方法。

关键词：超光谱侦察传感器光电设计

在线全文

学校读者我要写书评

暂无评论

基于PCA的相机响应函数特征化方法研究

北京理工大学学报 2015年第10期35卷 1085-1089页

作者：裘溯金伟其北京理工大学光电学院光电成像技术与系统教育部重点实验室北京100081

响应函数是CCD和CMOS成像器件的重要特性之一.传统的响应函数测试方法存在对实验条件要求苛刻、测试速度慢、人工成本高等不足.基于201条已有的响应函数曲线,采用PCA方法提取相机响应函数空间中对应5个最大特征值的特征向量,并用这5个... 详细信息

响应函数是CCD和CMOS成像器件的重要特性之一.传统的响应函数测试方法存在对实验条件要求苛刻、测试速度慢、人工成本高等不足.基于201条已有的响应函数曲线,采用PCA方法提取相机响应函数空间中对应5个最大特征值的特征向量,并用这5个特征向量的线性组合表达已有的201条响应函数曲线,取得了较高的精度.对4种不在响应函数库中的数码相机响应函数进行了特征向量表达,也获得了较高的精度,证明相机响应函数空间特征向量能够表达任意相机的响应函数.

关键词： PCA 相机响应函数特征化

Enhancement of comprehensive properties of Nb–Si based in-situ composites by Ho rare earth doping

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第9期43卷 4508-4520页

作者： wei wei qi Wang Rui-Run Chen Chao-Wen Zheng Yan-qing Su National Key Laboratory for Precision Hot Processing of Metals School of Materials Science and EngineeringHarbin Institute of Technology

This study examines the microstructure,mechanical properties （with a focus on room-temperature toughness）, and oxidation resistance of Ho-doped NbDSi based in-situ composites. The base alloy consists of the coarse primary Nb5Si3phase and the Nb5Si3+Nbss （Nb solid solution） eutectic cells. Ho doping influences the solidification path. When the Ho doping is higher than0.2 at%, the alloys transform into eutectic alloys. Ho can be solid-solved in trace amounts in the Nbss phase. However, most of Ho forms a stable Ho oxide phase, which alleviates oxygen contamination problem to some ***, the interface separation between Ho oxide and other phases reduces the plastic deformation ***, with 0.4 at%Ho doping, the KQvalue is18.03 MPa·m1/2, which is 31.1%higher than that of the base alloy. The strength of the Ho-doped alloys does not deteriorate with an increase in toughness. However, the large network-like Ho2O3in the 0.8Ho alloy causes a decrease in toughness and strength. In addition, the Ho oxide phase effectively blocks the inward oxygen *** 0.8 at%Ho doping, the oxidation mass gain per unit area is 10.16 mg·cm2, which is 39.7%lower than that of the base alloy.

关键词： Ho Microstructure Nb–Si based composites Properties Rare earth elements

Top Five Stories of the Cellular Landscape and Therapies of Atherosclerosis:Current Knowledge and Future Perspectives

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Current Medical Science 2024年第1期44卷 1-27页

作者： qi PAN Cheng CHEN Yue-jin YANG State Key Laboratory of Cardiovascular Disease Department of CardiologyFuwai HospitalNational Center for Cardiovascular DiseasesChinese Academy of Medical Science and Peking Union Medical CollegeBeijing 100037China

Atherosclerosis(AS)is characterized by impairment and apoptosis of endothelial cells,continuous systemic and focal inflammation and dysfunction of vascular smooth muscle cells,which is documented as the traditional cellular ***,the mechanisms appear much more complicated than we thought since a bulk of studies on efferocytosis,transdifferentiation and novel cell death forms such as ferroptosis,pyroptosis,and extracellular trap were *** of novel pathological cellular landscapes provides a large number of therapeutic *** the other side,the unsatisfactory therapeutic effects of current treatment with lipid-lowering drugs as the cornerstone also restricts the efforts to reduce global AS *** cell-or nanoparticle-based strategies spurred a lot of attention due to the attractive therapeutic effects and minimized adverse *** the complexity of pathological changes of AS,attempts to develop an almighty medicine based on single mechanisms could be theoretically *** this review,the top stories in the cellular landscapes during the initiation and progression of AS and the therapies were summarized in an integrated perspective to facilitate efforts to develop a multi-targets strategy and fill the gap between mechanism research and clinical *** future challenges and improvements were also discussed.

关键词： atherosclerosis transdifferentiation extracellular traps efferocytosis stem cell nanoparticles

High-Order Two-Scale Asymptotic Paradigm for the Elastodynamic Homogenization of Periodic Composites

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

Acta Mechanica Solida Sinica 2024年第1期37卷 124-138页

作者： wei-Zhi Luo Mu He Liang Xia qi-Chang He State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China Laboratoire Modélisation et Simulation Multi-Echelle MSME UMR 8208 CNRSUniversite Gustave Eiffel77454 Marne-la-ValléeFrance

The classical two-scale asymptotic paradigm provides macroscopic and microscopic analyses for the elastodynamic homogenization of periodic composites based on the spatial or/and temporal variable,which offers an approximate framework for the asymptotic homogenization analysis of the motion ***,in this framework,the growing complexity of the homogenization formulation gradually becomes an obstacle as the asymptotic order *** such a context,a compact,fast,and accurate asymptotic paradigm is *** work reviews the high-order spatial two-scale asymptotic paradigm with the effective displacement field representation and optimizes the implementation by symmetrizing the tensor to be ***,the modified implementation gets rid of the excessive memory consumption required for computing the high-order tensor,which is demonstrated by representative one-and two-dimensional *** numerical results show that(1)the contrast of the material parameters between media in composites directly affects the convergence rate of the asymptotic results for the homogenization of periodic composites,(2)the convergence error of the asymptotic results mainly comes from the truncation error of the modified asymptotic homogenized motion equation,and(3)the excessive norm of the normalized wavenumber vector in the two-dimensional inclusion case may lead to a non-convergence of the asymptotic results.

关键词： Composites Homogenization Asymptotic analysis Dynamics Dispersion

Emergency management capacity assessment for urban rail transit-an example of Beijing Metro Line 13

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

Transportation Safety and Environment 2024年第1期6卷 109-115页

作者： Jiao Liu Yun qi wei Wang School of Emergency Management and Safety Engineering China University of Mining&Technology(Beijing)Beijing 100083China China Safety Science Journal Editorial Department China Occupational Safety and Health AssociationBeijing 100011China College of mechanical engineering and automation Liaoning University of TechnologyJinzhou 121001LiaoningChina

In order to improve the emergency management capability of urban rail transit system and reduce accidents during metro operation,an emergency management capability evaluation method combining analytic hierarchy process(AHP)and technique for order preference by similarity to ideal solution(TOPSIS)is *** on the Prevention Preparation Response Recovery(PPRR)model,factors influencing the emergency management capability of the urban rail transit system are summarized from the perspective of‘human,machine,environment and management’.Then,an emergency management capability evaluation index system containing of 20 secondary indicators is constructed in four stages:emergency prevention,emergency preparation,emergency response and emergency *** weights of indicators are calculated using the AHP method,and the closeness of each indicator to the optimal solution is analysed with the TOPSIS ***,take the Beijing Metro Line 13 as an example to investigate the level of emergency management capability of urban rail *** results show that the emergency management capability of Beijing’s urban rail transit system is‘well’,among which hazard prevention measures(0.31)and emergency response team(0.34)have a greater weight on the emergency management capability of rail *** model can more accurately assess the emergency management capability of urban rail transit and provide a basis for emergency management.

关键词： urban rail transit emergency management capability analytic hierarchy process(AHP) technique for order preference by similarity to ideal solution(TOPSIS) prevention preparation response recovery(PPRR)model

Lift-Off Effect of Koch and Circular Differential Pickup Eddy Current Probes

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2024年第2期37卷 283-293页

作者： Guolong Chen Zheng Cao Shuaishuai Zhang Ji wei wei Gao Wuyin jin School of Mechanical and Electrical Engineering Lanzhou University of TechnologyLanzhou 730050China

A flexible or planar eddy current probe with a differential structure can suppress the lift-off noise during the inspection of ***,the extent of the lift-off effect on differential probes,including different coil structures,*** this study,two planar eddy current probes with differential pickup structures and the same size,Koch and circular probes,were used to compare lift-off *** eddy current distributions of the probes perturbed by 0°and 90°cracks were obtained by finite element *** analysis results show that the 90°crack can impede the eddy current induced by the Koch probe even further at relatively low lift-off *** peak-to-peak values of the signal output from the two probes were compared at different lift-off distances using finite element analysis and experimental *** addition,the effects of different frequencies on the lift-off were studied *** results show that the signal peak-to-peak value of the Koch probe for the inspection of cracks in 90°orientation is larger than that of the circular probe when the lift-off distance is smaller than 1.2 *** addition,the influence of the lift-off distance on the peak-to-peak signal value of the two probes was studied via *** indicates that the influence becomes more evident with an increase in excitation *** research discloses the lift-off effect of differential planar eddy current probes with different coil shapes and proves the detection merit of the Koch probe for 90°cracks at low lift-off distances.

关键词： Eddy current testing Differential pickup probe Fractal Koch curve Flexible eddy current probe

MOF and its derivative materials modified lithium-sulfur battery separator:a new means to improve performance

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第6期43卷 2418-2443页

作者： Rong-wei Huang Yong-qi Wang Dan You Wen-Hao Yang Bin-Nan Deng Fei Wang Yue-jin Zeng Yi-Yong Zhang Xue Li National Local Joint Engineering Research Center for Lithium-Ion Batteries and Materials Preparation Technology Key Laboratory of Advanced Batteries Materials of Yunnan ProvinceFaculty of Metallurgical and Energy EngineeringKunming University of Science and TechnologyKunming 650093China State Key Laboratory of Physical Chemistry of Solid Surfaces Collaborative Innovation Centre of Chemistry for Energy MaterialsState-Province Joint Engineering Laboratory of Power Source Technology for New Energy VehicleEngineering Research Center of Electrochemical TechnologyMinistry of EducationCollege of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China

In recent years,lithium-sulfur batteries(LSBs)are considered as one of the most promising new generation energies with the advantages of high theoretical speeific capacity of sulfur(1675 mAh·g^(-1)),abundant sulfur resources,and environmental friendliness storage technologies,and they are receiving wide attention from the ***,the problems of the shuttle effect and lithium dendrite growth in LSBs have limited their practical application,so there is a need to find ways to solve these *** is an excellent choice to use novel materials to modify battery *** those novel materials,the metal-organic framework(MOF)has the properties of regular pores and controllable *** applied as a positive electrode and diaphragm,it can restrain the shuttle effect and lithium dendrite growth,especially since it shows excellent performance in diaphragm ***,various design strategies and synthesis methods of MOF-modified separators are reviewed in this paper,and the applications of MOF in LSBs separators in different forms are introduced,including the composite of MOF and carbon-based materials,the compounding of MOF and polymer,self-carbonization to form MOF-derived *** the same time,different characterization techniques are systematically reviewed to obtain the physical and chemical properties of MOF particles and the working mechanism of MOF-modified diaphragm,which provides a basis for further research in this ***,some future research trends and directions are put forward to fully tap the future commercial potential of MOF-modified diaphragm in LSBs.

关键词： MOF Lithium-sulfur battery Modified diaphragms Design strategies Prospect Characterization