检索结果-南通市图书馆

A time-sharing multi-channel pulse amplitude analyzer

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2017年第4期28卷 91-96页

作者： Lian-Jun Jiang Xiang Zhou Tong-Yu Wu ze-Jie yin State Key Laboratory of Particle Detection and Electronics University of Science and Technology of China Department of Modern Physics University of Science and Technology of China

A conventional multi-channel pulse amplitude analyzer acquires single energy spectrum,but provides no information on its tendency with *** address the limitation,we propose a scheme of time-sharing multichannel pulse amplitude analyzer(TSMCA).A dual-port random access memory is divided into two storage spaces,one for current energy spectrum data acquisition and another for previous energy spectrum data *** two tasks can be performed simultaneously,and the time-related variation tendency of energy spectrum can be obtained.A prototype system of TSMCA is *** performs nicely,with maximum channel number of 4096 in capacity of 2^(32)/Ch,minimal time-sharing slice of 25 ms,the differential nonlinearity of <1.5%,and the integral nonlinearity of <0.3%.

关键词： Multi-channel pulse amplitude analyzer MCA Time-sharing ADC Dual-port RAM

An approach to estimate tree height using PolInSAR data constructed by the Sentinel-1 dual-pol SAR data and RVoG model

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3期22卷 69-79页

作者： yin Zhang Ding-feng Duan School of Resources and Environment University of Electronic Science and Technology of ChinaChengdu611731China

We estimate tree heights using polarimetric interferometric synthetic aperture radar(PolInSAR)data constructed by the dual-polarization(dual-pol)SAR data and random volume over the ground(RVoG)*** the Sentinel-1 SAR dual-pol(SVV,vertically transmitted and vertically received and SVH,vertically transmitted and horizontally received)configuration,one notes that S_(HH),the horizontally transmitted and horizontally received scattering element,is *** S_(HH)data were constructed using the SVH data,and polarimetric SAR(PolSAR)data were *** proposed approach was first verified in simulation with satisfactory *** was next applied to construct PolInSAR data by a pair of dual-pol Sentinel-1A data at Duke Forest,North Carolina,*** to local observations and forest descriptions,the range of estimated tree heights was overall *** the heights with the ICESat-2 tree heights at 23 sampling locations,relative errors of 5 points were within±30%.Errors of 8 points ranged from 30%to 40%,but errors of the remaining 10 points were>40%.The results should be encouraged as error reduction is *** instance,the construction of PolSAR data should not be limited to using SVH,and a combination of SVH and SVV should be ***,an ensemble of tree heights derived from multiple PolInSAR data can be considered since tree heights do not vary much with time frame in months or one season.

关键词： Constructed polarimetric SAR data Dual polarization Sentinel-1 SAR data Polarimetric interferometric SAR Random volume over the ground model Tree height estimation

DISPERSION STABILITY AND RHEOLOGICAL BEHAVIOR OF SUSPENSIONS OF POLYSTYRENE COATED FUMED SILICA PARTICLES IN POLYSTYRENE SOLUTIONS

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

Chinese Journal of Polymer Science 2012年第1期30卷 26-35页

作者： Xian-ze yin Ye-qiang Tan Yi-hu Song Qiang Zheng Key Laboratory of Macromolecular Synthesis and Functionalization of Ministry of Education Zhejiang University Hangzhou 310027 China Department of Polymer Science and Engineering Zhejiang University Hangzhou 310027 China

Polystyrene coated silica（SiO_2@PS） core-shell composite particles with averaged diameter of about 290 nm were prepared by in situ emulsion polymerization of styrene on the surface ofγ-methacryloxypropyltrimethoxysilane grafted SiO_2 nanoparticles of 20-50 nm in *** behavior and dispersion stability of SiO_2@PS suspension in 10 wt%PS solution were compared with suspensions of untreated SiO_2 and silane modified SiO_2 *** of the untreated and the silane modified SiO_2 exhibited obvious shear *** SiO-2@PS suspension exhibits shear viscosity considerably smaller than suspensions of untreated and silane modified SiO_2 at low shear *** electron microscopy showed that the composite particles can uniformly and stably disperse in PS solution compared to other suspensions,implying that the PS shell can effectively enhance the particle compatibility with PS macromolecules in solution.

关键词： Fumed SiO_2 Polystyrene Composite particles Suspension Steady rheology

Magnetoresistive behavior and magnetization reversal of NiFe/Cu/CoFe/IrMn spin valve GMRs in nanoscale

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2013年第7期20卷 700-704页

作者： Cong yin ze Jia Wei-chao Ma Tian-ling Ren Institute of Microelectronics & Tsinghua National Laboratory for Information Science and Technology Tsinghua University

The magnetoresistance behavior and the magnetization reversal mode of NiFe/Cu/CoFe/IrMn spin valve giant magnetoresistance （SV-GMR） in nanoscale were investigated experimentally and theoretically by nanosized magnetic simulation methods. Based on the Landau-Lifshitz-Gilbert equation, a model with a special gridding was proposed to calculate the giant magnetoresistance ratio （MR） and investigate the magnetization reversal mode. The relationship between MR and the external magnetic field was obtained and analyzed. Studies into the variation of the magnetization distribution reveal that the magnetization reversal mode, that is, the jump variation mode for NiFe/Cu/CoFe/IrMn, depends greatly on the antiferromagnetic coupling behavior between the pinned layer and the antiferromagnetic layer. It is also found that the switching field is almost linear with the exchange coefficient.

关键词： giant magnetoresistance (GMR) spin valves nanoscale magnetization reversal

Recent advances towards catalytic asymmetric Conia-ene-type reactions

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2021年第3期32卷 954-962页

作者： En-ze Lin yin Xu Kegong Ji Long-Wu Ye College of Chemistry and Pharmacy Northwest A&F UniversityShaanxi Key Laboratory of Natural Products&Chemical BiologyYangling 712100China The Key Laboratory for Chemical Biology of Fujian Province and State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China State Key Laboratory of Organometallic Chemistry Chinese Academy of SciencesShanghai 200032China

Conia-ene reactions,as a type of ene reactions,have not become a remarkable focus until the beginning of21st century,when Lewis acids served as powerful catalysts and found an increasingly broad utilization in this ***,the catalytic Conia-ene reactions have gained great significance in synthetic chemistry due to their high efficiency and atom economy on the construction of valuable cyclic *** the past two decades,the rapid development of transition-metal catalysis and organocatalysis has imposed a profound impact on the exploration of asymmetric Conia-ene *** a result,several strategies have been developed and applied *** on the basis of the catalytic system,this review comprehensively presents a summary of recent progress achieved in this emerging domain,aimed at highlighting the reactions’features,practicalities,and the mechanistic rationale is presented where possible.

关键词： Conia-ene reaction Asymmetric catalysis Transition metals Organocatalysts

NONLINEAR VIBRATION OF THE COUPLED STRUCTURE OF SUSPENDED-CABLE-STAYED BEAM-1:2 INTERNAL RESONANCE

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2014年第5期27卷 467-476页

作者： Kun Huang Qi feng Yajun yin School of Aerospace Engineering and Applied Mechanics Tongji University Department of Engineering Mechanics School of Aerospace Tsinghua University

Through the Galerkin method the nonlinear ordinary differential equations （ODEs） in time are obtained from the nonlinear partial differential equations （PDEs） to describe the mo- tion of the coupled structure of a suspended-cable-stayed beam. In the PDEs, the curvature of main cables and the deformation of cable stays are taken into account. The dynamics of the struc- ture is investigated based on the ODEs when the structure is subjected to a harmonic excitation in the presence of both high-frequency principle resonance and 1：2 internal resonance. It is found that there are typical jumps and saturation phenomena of the vibration amplitude in the struc- ture. And the structure may present quasi-periodic vibration or chaos, if the stiffness of the cable stays membrane and frequency of external excitation are disturbed.

关键词： the coupled structure of suspended-cable-stayed beam the multiscale method 1:2internal resonance Hopf bifurcation chaos

Study on the Geo-Environmental Evolution of the Laolonggou Lagoon Under the Impacts of the Caofeidian Reclamation Project in Hebei Province

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean University of China 2020年第5期19卷 1062-1072页

作者： yin Cong YE Siyuan feng Xiuli yin Yanhong Key Laboratory of Submarine Geosciences and Prospecting Techniques Ministry of Education and College of Marine GeosciencesOcean University of ChinaQingdao 266100China Key Laboratory of Coastal Wetland Biogeosciences China Geological SurveyQingdao 266071China North China Sea Bureau Ministry of Natural ResourcesQingdao 266033China Qingdao Institute of Marine Geology China Geological SurveyQingdao 266071China

The Caofeidian Reclamation Project has been the biggest reclamation project in China so far, in which 310 km^2 sea areas were reclaimed along the coast of Hebei Province, and it also bring about many problems and defects for large reclaiming area. The study focuses on the influences of the engineering exerted on evolution of the Laolonggou Lagoon with the methods of topographical measurement and surface sediment analysis. The results demonstrate that the topographical changes in the Laolonggou Lagoon had been controlled obviously by the engineering at three stages. Besides, blocking and reopening of the shoal tidal channel also affected the geological environment of the lagoon area. In the aspect of topographical change, the Laolonggou Inlet first experienced deposition after the shoal tidal channel was blocked, followed by short-time eroding for quarrying and cofferdam construction in the east, then depositing slowly after the reclaiming activity ceased, and finally eroding after the shoal tidal channel was reopened. The project, particularly cofferdam construction led to the movement of the Laolonggou Inlet axis from west to east for 50 – 100 m. In the aspect of sediment variation, the reclamation project and hydrodynamic change resulted in the variation in compositions and distribution pattern. The western lagoon area has become land mainly constituted by silt, while the sediments in the eastern area have turned finer in size. After the shoal tidal channel was reopened, the current velocity in the Laolonggou Inlet has been enhanced, making the sediments at the bottom become coarser. The sediments around the Caofeidian foreland went through a process of changing in grain size from fine to coarse and back to fine again, and the sediments are mainly constituted by silt at present.

关键词： Laolonggou Lagoon Inlet topographical evolution Caofeidian Reclamation Project shoal tidal channel

Nanosheet-coated synthetic wood with enhanced flame-retardancy by vacuum-assisted sonocoating technique

在线全文

学校读者我要写书评

暂无评论

Nano Research 2022年第10期15卷 9440-9446页

作者： Zhi-Yuan Ma Xiao-feng Pan ze-Lai Xu Zhi-Long Yu Bing Qin Yi-Chen yin Yu-Cheng Gao Shu-Hong Yu Department of Chemistry Institute of Biomimetic Materials&ChemistryAnhui Engineering Laboratory of Biomimetic MaterialsDivision of Nanomaterials&ChemistryHefei National Laboratory for Physical Sciences at the MicroscaleInstitute of EnergyHefei Comprehensive National Science CenterUniversity of Science and Technology of ChinaHefei 230026China Department of Modern Mechanics University of Science and Technology of ChinaHefei 230027China

Compared to natural woods,synthetic woods have superior mechanical stability,thermal insulation,and flame retardancy owing to their hierarchically cellular microstructures and intrinsic advantages of the thermosetting *** the long-time fire resistance is very important to the practical *** this study,we present a novel coating strategy by a vacuum-assisted sonication technique(sonocoating)with a rectorite nanosheet dispersion to create a uniform nanocoating on the channel walls of synthetic *** to ultrasonic energy and vacuum pressure,the nanosheet dispersion can penetrate deep down to form a layered nanocoating on the channel *** coated synthetic woods can withstand fire(400-600℃)for more than 10 min with 62%mass retainment,surpassing uncoated synthetic woods and natural ***,as a lightweight and strong composite with enhanced flame-retardant performance,the coated synthetic woods have huge potential applications in safe and energy-efficient buildings.

关键词： synthetic wood sonocoating vacuum infiltration rectorite nanosheets flame-retardant

Adaptive variational models for image decomposition combining staircase reduction and texture extraction

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

Journal of Systems Engineering and Electronics 2009年第2期20卷 254-259页

作者： Jiang Lingling yin Haiqing feng Xiangchu School of Mathematics and Computational Science China Univ. of Petroleum Dongying 257061 P. R. China School of Science Xidian Univ. Xi'an 710071 P. R. China

New models for image decomposition are proposed which separate an image into a cartoon, consisting only of geometric objects, and an oscillatory component, consisting of textures or noise. The proposed models are given in a variational formulation with adaptive regularization norms for both the cartoon and texture parts. The adaptive behavior preserves key features such as object boundaries and textures while avoiding staircasing in what should be smooth regions. This decomposition is computed by minimizing a convex functional which depends on the two variables u and v, alternatively in each variable. Experimental results and comparisons to validate the proposed models are presented.

关键词： image decomposition total variation minimization bounded variation texture