检索结果-南通市图书馆

Chinese Chemical Letters 1996年第11期7卷 975-978页

作者： li T.s. li s.h. li J.T. li h.Z. Wu X.X. Department of Chemistry Hebei University Baoding 071002 Hebei Province

Acetalization of steroid ketones and cleavage of the acetals.h.ve ben carried out inexcellent yield under catalysis of montmorillonite K 10.

关键词： montmorillonite catalysed steroid cleavage Convenient

Editorial for the special Issue on Emerging Technology and Advanced Application of Nondestructive Detection for Power Equipment

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electrical Engineering 2024年第1期10卷 1-2页

作者： li J. Mei h. li s. Tianjin University China Tsinghua shenzhen International Graduate s.h.ol China Lanzhou Jiaotong University China

The rapid development of clean and renewable energy technologies represented by wind and solar energy,as well as the continuous growth of load demand,have put forward higher requirements for the safe operation of the power *** performance of power equipment based on traditional dielectric materials is often limited by various defects generated during molding,transportation,assembly,and operation,which cannot meet the reliability requirements of power systems in the new *** detection is an essential technical method in industrial development,which can detect and evaluate the defect and damage status of in-service equipment,key components,and materials without damaging the object.

关键词： service Application operation

Fast efficient photon deceleration in plasmas by using two laser pulses at different frequencies

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Matter and Radiation at Extremes 2024年第3期9卷 11-18页

作者： Y.X.Wang X.L.Zhu s.M.Weng P.li X.F.li h.Ai h.R.Pan Z.M.sheng Key Laboratory for Laser Plasmas(moe) School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Center of IFsA Shanghai Jiao Tong UniversityShanghai 200240China Research Center of Laser Fusion of China Academy of Engineering Physics MianyangSichuan 621900China state key Laboratory of high Field Laser Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China Tsung-dao Lee Institute Shanghai Jiao Tong UniversityShanghai 200240China

The generation of ultrashort high-power light sources in the mid-infrared(mid-IR)to terahertz(Thz)range is of interest for applications in a number of fields,from fundamental research to biology and *** conventional laser technology,photon deceleration in plasma wakes provides an alternative approach to the generation of ultrashort mid-IR or Thz ***,we present a photon deceleration s.h.me for the efficient generation of ultrashort mid-IR or Thz pulses by using an intense driver laser pulse with a relatively short wavelength and a signal laser pulse with a relatively long *** signal pulse trails the driver pulse with an appropriate time delay such that it sits at the front of the second wake bubble that is driven by the driver *** to its relatively long wavelength,the signal pulse will be subjected to a large gradient of the refractive index in the plasma wake ***,the photon deceleration in the plasma wake becomes faster and more efficient for signal pulses with longer *** greatly enhances the capacity and efficiency of photon deceleration in the generation of ultrashort high-power light sources in the long-wavelength IR and Thz spectral ranges.

关键词： laser ultrashort photon

Tribological behavior of lubricant-impregnated porous polyimide

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Friction 2024年第4期12卷 711-725页

作者： Jinbang li Ningning ZhOU Janet s.s.WONG s.h.ol of Mechanical Engineering and Mechanics Ningbo UniversityNingbo 315211China Beijing Key Laboratory of Long-life Technology of Precise Rotation and Transmission Mechanisms Beijing Institute of Control EngineeringBeijing 100029China Department of Mechanical Engineering Imperial College LondonLondon SW72AZUK

Porous materials impregnated with lubricants can be used in conditions where limited lubricant is *** this work,three porous polyimides(PPI)with different densities were ***(PAO)impregnated PPI(iPPI)discs were rubbed against steel and sapphire *** operando observations of the iPPI-sapphire contacts show that oil is released under an applied load,forming a meniscus around *** at the outlet is created at high sliding *** amount of released oil increases with increasing PPI *** moduli,E*,estimated based on the actual contact size show that trapped oil in iPPIs contributes to load *** higher speeds,tribological rehydration of the contact occurs in low density iPPI,with that E*rises with *** high density PPIs.h.gh speeds give a constantly high E*which is limited by the viscoelastic properties of the PPI network and possibly the rate of oil *** of iPPI-steel contacts is governed by the mechanical properties of the PPI,the flow of the lubricant,and the roughness of the PPI *** low-and medium-density(highly porous.h.gh roughness)PPIs,large amount of oil is released,and lubrication is mainly via lubricant restricted in the contact in the pores and possibly tribological *** high density(low porosity)PPI,with lower roughness.h.drodynamic lubrication is achieved which gives the lowest *** results show that polymeric porous materials for effective lubrication require the optimization of its surface roughness,stiffness,oil flow,and oil retentions.

关键词： polyimide porous material friction mechanism polymer limited lubrication

Atomistic Investigation of shock-Induced Amorphization within Micro-shear Bands in hexagonal Close-Packed Titanium

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 Metallurgica sinica(English Letters) 2024年第9期37卷 1590-1600页

作者： Z.C.Meng K.G.Wang T.Ali D.li C.G.Bai D.s.Xu s.J.li A.h.Feng G.J.Cao J.h.Yao Q.B.Fan h.Wang R.Yang Institute of Metal Research Chinese Academy of SciencesShenyang 110016China s.h.ol of Materials science and Engineering University of Science and Technology of ChinaShenyang 110016China Interdisciplinary Centre for Additive Manufacturing(ICAM) School of Materials and ChemistryUniversity of Shanghai for Science and TechnologyShanghai 200093China s.h.ol of Materials science and Engineering Tongji UniversityShanghai 201804China Key Laboratory for light-Weight Materials Nanjing Tech UniversityNanjing 210009China National Key Laboratory of science and Technology on Materials Under shock and Impact School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401135China

The mechanical response of a single crystal titanium sample against(0001)α surface impact was investigated using molecular dynamics ***,non-uniform plastic deformation was observed in the *** high strain rates,amorphization occurred near the edge of the contact region where severe shear strain induced a large number of stacking faults(sFs)and *** contrast,the central part of the contact region underwent less deformation with significantly fewer ***,instead of amorphization by consuming sFs and dislocations,there was a gradual increase in the density of dislocations and sFs during the process of *** local amorphous regions eventually grew into shear bands.

关键词： shock compression Amorphization shear band Titanium Molecular dynamics

Convexification of hybrid AC-DC Optimal Power Flow with line-Commutated Converters

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

CsEE Journal of Power and Energy systems 2024年第2期10卷 617-628页

作者： hongyuan liang Zhigang li J.h.Zheng Q.h.Wu s.h.ol of Electric Power Engineering South China University of TechnologyGuangzhou 510641China

line-commutated converter (LCC)-based high-voltage DC (hVDC) systems.h.ve been integrated with bulk AC power grids for interregional transmission of renewable power. The nonlinear LCC model brings additional nonconvexity to optimal power flow (OPF) of hybrid AC-DC power grids. A convexification method for the LCC station model could address such nonconvexity but has rarely been discussed. We devise an equivalent reformulation for classical LCC station models that facilitates second-order cone convex relaxation for the OPF of LCC-based AC-DC power grids. We also propose sufficient conditions for exactness of convex relaxation with its proof. Equivalence of the proposed LCC station models and properties, exactness, and effectiveness of convex relaxation are verified using four numerical simulations. simulation results demonstrate a globally optimal solution of the original OPF can be efficiently obtained from relaxed model.

关键词： AC-DC power system convex relaxation linecommutated converter optimal power flow second-order cone programming

A hybrid signal Processing Method Combining Mathematical Morphology and Walsh Theory for Power Quality Disturbance Detection and Classification

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

CsEE Journal of Power and Energy systems 2024年第2期10卷 584-592页

作者： Zhi Ding Tianyao Ji Mengshi li Q.h.Wu s.h.ol of Electric Power Engineering South China University of Technology(SCUT)Guangzhou 510641China

In this paper, a novel signal processing method combining mathematical morphology (MM) and Walsh theory is proposed, which uses Walsh functions to control the structuring element (sE) and MM operators. Based on the Walsh-MM method, a s.h.me for power quality disturbances detection and classification is developed, which involves three steps: denoising, feature extraction and morphological clustering. First, various evolution rules of Walsh function are used to generate groups of sEs for the multiscale Walsh-ordered morphological operation, so the original signal can be denoised. Next, the fundamental wave of the denoised signal is suppressed by hadamard matrix;thus, disturbances can be extracted. Finally, the Walsh power spectrum of the waveform extracted in the previous step is calculated, and the parameters of which are taken by morphological clustering to classify the disturbances. simulation results reveal the proposed s.h.me can effectively detect and classify disturbances, and the Walsh-MM method is less affected by noise and only involves simple calculation, which has a potential to be implemented in hardware and more suitable for real-time application.

关键词： hadamard matrix mathematical morphology morphological clustering power quality disturbance Walsh theory

Evaluation of E-sail parameters on central spacecraft attitude stability using a high-fidelity rigid–flexible coupling model

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Astrodynamics 2024年第2期8卷 271-284页

作者： Chonggang Du Zheng h.Zhu Changqing Wang Aijun li Tuanjie li s.h.ol of Electro-Mechanical Engineering Xidian UniversityXi’an 710071China Department of Mechanical Engineering York University4700 Keele StreetTorontoOntario M3J 1P3Canada s.h.ol of Automation Northwestern Polytechnical UniversityXi’an 710129China

This study examines the impact of electric solar wind sail(E-sail)parameters on the attitude stability of E-sail’s central spacecraft by using a comprehensive rigid–flexible coupling dynamic *** this model,the nodal position finite element method is used to model the elastic deformation of the tethers through interconnected two-node tensile *** attitude dynamics of the central spacecraft is described using a natural coordinate *** rigid–flexible coupling between the central spacecraft and its flexible tethers is established using Lagrange *** research reveals the significant influences of parameters such as tether numbers,tether’s electric potential,and solar wind velocity on attitude ***,solar wind fluctuations and the distribution of electric potential on the main tethers considerably affect the attitude stability of the *** consistent management,the angular velocities of the spacecraft must remain at target ***,the attitude stability of a spacecraft has a pronounced dependence on the geometrical configuration of the E-sail,with axisymmetric E-sails proving to be more stable.

关键词： electric solar wind sail(E-sail) space tether nodal position finite element method(NPFEM) natural coordinate formulation (NCF) attitude stability

Observability Analysis of Integrated Electricity and heating systems with Thermal Quasi-dynamics in Pipelines

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

CsEE Journal of Power and Energy systems 2024年第3期10卷 1145-1158页

作者： Zhigang li Wenjian Zheng Junbo Zhao J.h.Zheng Q.h.Wu s.h.ol of Electric Power Engineering South China University of TechnologyGuangzhou 510641China Fuzhou Changle District Power supply Company of state Grid Fujian Electric Power Co. Ltd.Fuzhou 350000China Department of Electrical and Computer Engineering University of ConnecticutStorrsCT 06269USA CsEE IEEE

Observability analysis(OA)is vital to obtaining the available input measurements of state estimation(sE)in an integrated electricity and heating system(IEhs).Considering the thermal quasi-dynamics in pipelines,the measurement equations in heating systems are dependent on the estimated results,leading to an interdependency between OA and *** OA methods require measurement equations be known exactly before sE is performed,and they are not applicable to *** bridge this gap,a scenario-based OA s.h.me for IEhss is devised that yields reliable analysis results for a predefined set of time-delay scenarios to cope with this *** its core procedure,the observable state identification and observability restoration are formulated in terms of integer linear *** tests are conducted to demonstrate the validity and superiority of the proposed formulation.

关键词： Integrated electricity and heating system measurement observability analysis state estimation thermal quasi-dynamics

Tau in the pancreas:understanding the link between type 2 diabetes mellitus and Alzheimer's disease

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

signal Transduction and Targeted Therapy 2024年第1期9卷 6-7页

作者： Wenlu li steffen Tiedt Eng h.Lo Neuroprotection Research Laboratories Departments of Radiology and NeurologyMassachusetts General HospitalHarvard Medical SchoolCharlestownMA02129USA Consortium International pour la Recherche Circadienne sur l’AVC(CIRCA) BostonUSA Institute for stroke and Dementia Research LMU University HospitalLMU MunichMunichGermany

A recent study published in Molecular Psychiatry proposes a cellular mechanism that may contribute to decreased insulin production in individuals with type 2 diabetes mellitus(T2DM).1 Using a combination of cell culture experiments,animal models and studies in T2DM patients,the authors show that an up-regulation of tau inβ-islet cells can inhibit pancreatic insulin secretion through changes in microtubule assembly.

关键词： T2DM Alzheimer tau