检索结果-南通市图书馆

Rare Metals 2012年第1期31卷 12-16页

作者： Shen, jun xu, Nan College of Materials Science & Engineering Chongqing University Chongqing 400044 China

The effects of solution and aging treatments on the microstructures and mechanical properties of tungsten inert gas arc welded AZ61 magne-sium alloy joints were investigated by microstructural observations,microhardness tests and tensile *** results showed that the solution treatment led to the β-Mg17Al12 particles dissolved into the α-Mg ***,the microhardness of the fusion zone and the ultimate tensile strength of the welded joints were the *** the increase of the aging temperature,the volume fraction of the β-Mg17Al12 particles in the fusion zone increased and this enhanced the microhardness of the fusion zone ***,the elongation of the welded joints was in-creased slightly with the increase of the volume fraction of the β-Mg17Al12 ***,the ultimate tensile strength of the welded joints increased at first and dropped at 190 ?C due to cracks formed at the boundaries of the β-Mg17Al12 particles.

关键词： magnesium alloy heat treatment microstructure mechanical properties

在线全文

学校读者我要写书评

暂无评论

融合前缀调优和提示学习的仇恨言论检测方法

计算机科学与探索 2025年第1期19卷 97-106页

作者：徐磊胡亚豪陈满陈军潘志松中国人民解放军陆军工程大学指挥控制工程学院

随着网络社交平台的发展，网络暴力的危害性日益凸显，其中仇恨言论作为网络暴力的一种表现形式，对其检测方法的研究有助于构建一个健康的互联网环境。然而，一方面先前的仇恨言论检测方法主要依赖于人工监管和关键词过滤，这些方法存... 详细信息

随着网络社交平台的发展，网络暴力的危害性日益凸显，其中仇恨言论作为网络暴力的一种表现形式，对其检测方法的研究有助于构建一个健康的互联网环境。然而，一方面先前的仇恨言论检测方法主要依赖于人工监管和关键词过滤，这些方法存在人工成本高且分类效果不佳的问题；另一方面，在互联网平台的监管下，仇恨言论的表达也变得更加含蓄、隐蔽，这对检测模型的文本理解能力提出了更高的要求。以ChatGPT为代表的大模型为仇恨言论检测任务提供了新的可能性，受其在各项下游任务中出色表现的启发，提出了一种融合前缀调优和提示学习的仇恨言论检测方法P-Prompt。利用前缀调优方法将大模型在相关数据集上进行微调，同时结合提示学习方法使模型能够识别并关注待检测文本中的仇恨言论词汇，从而进一步提升模型对仇恨言论的识别能力。实验结果验证了大模型在仇恨言论检测任务的有效性，与传统方法相比P-Prompt方法在仇恨言论检测的二分类和多分类任务中各项评价指标都取得了较明显的提升。

关键词：仇恨言论检测大语言模型前缀调优提示学习

Finite element model analysis of thermal failure in connector

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第3期8卷 397-402页

作者： WANG Xin xu Liang-jun Research Lab of Electric Contacts Beijing University of Posts ＆ Telecommunications Beijing 100876 China

Thermal analysis and thermal diagnose are important for small power connector especially in electronic devices since their structure is usually compact. In this paper thermal behavior of small power connector was investigated. It was found that the contact resistance increased due to the Joule beating, and that increased contact resistance produced more Joule heating; this mutual action causes the connector to lose efficiency. The thermal distribution in the connector was analyzed using finite element method （FEM）. The failure mechanism is discussed. It provides basis for improving the structure. The conclusion was verified by experimental results.

关键词： Connector Stress relaxation Finite element method (FEM) Thermal failure

Control of firing activities in thermosensitive neuron by activating excitatory autapse

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2021年第10期30卷 171-179页

作者： Ying xu jun Ma School of Mathematics and Statistics Shandong Normal UniversityJi’nan 250014China Department of Physics Lanzhou University of TechnologyLanzhou 730050China School of Science Chongqing University of Posts and TelecommunicationsChongqing 430065China

Temperature has distinct influence on the activation of ion channels and the excitability of neurons,and careful change in temperature can induce possible mode transition in the neural *** formation and development of autapse connection to neuron can enhance its self-adaption to external stimulus,and thus the firing patterns in neuron can be controlled *** autapse is activated to drive a thermosensitive neuron,which is developed from the FitzHugh-Nagumo neural circuit by incorporating a thermistor,and the dynamics in the neural activities is explored to find mode dependence on the temperature and autaptic *** is found that the firing modes can be controlled by temperature,and the neuron is wakened from resting state to periodic oscillation with the increase of ***,the intensity and the intrinsic time delay in the autapse are respectively adjusted to control the neural activities,and it is confirmed that appropriate setting for autaptic current can balance and enhance the temperature effect on the neural activities.

关键词： thermosensitive neuron autapse firing pattern bifurcation

Energy Absorption Performance of Bio-inspired Honeycombs:Numerical and Theoretical Analysis

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2021年第6期34卷 884-894页

作者： John Sherman Wen Zhang jun xu Department of Mechanical Engineering and Engineering Science The University of North Carolina at CharlotteCharlotteNC 28223USA Vehicle Energy&Safety Laboratory(VESL) North Carolina Motorsports and Automotive Research CenterThe University of North Carolina at CharlotteCharlotteNC 28223USA

Energy absorption performance has been a long-pursued research topic in designing desired materials and structures subject to external dynamic *** by natural bio-structures,herein,we develop both numerical and theoretical models to analyze the energy absorption behaviors of Weaire,Floret,and Kagome-shaped thin-walled *** demonstrate that these bio-inspired structures possess superior energy absorption capabilities compared to the traditional thin-walled structures,with the specific energy absorption about 44%higher than the traditional *** developed mechanical model captures the fundamental characteristics of the bio-inspired honeycomb,and the mean crushing force in all three structures is accurately *** indicate that although the basic energy absorption and deformation mode remain the same,varied geometry design and the corresponding material distribution can further boost the energy absorption of the structure,providing a much broader design space for the next-generation impact energy absorption structures and systems.

关键词： Bio-inspired honeycomb Energy absorption Impact resistance Finite element analysis Modeling

The role of lipids in fermentative propionate production from the co-fermentation of lipid and food waste

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

Frontiers of Environmental Science & Engineering 2023年第7期17卷 107-118页

作者： Niyou xu Ting Chen jun Yin School of Environmental Science and Engineering Zhejiang Gongshang UniversityHangzhou 310012China Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling Hangzhou 310012China

Food waste(FW)is a promising renewable low-cost biomass substrate for enhancing the economic feasibility of fermentative propionate *** lipids,a common component of food waste,can be used as a carbon source to enhance the production of volatile fatty acids(VFAs)during co-fermentation,few studies have evaluated the potential for directional propionate production from the co-fermentation of lipids and *** this study,co-fermentation experiments were conducted using different combinations of lipids and FW for VFA *** contributions of lipids and FW to propionate production,hydrolysis of substrates,and microbial composition *** were *** results revealed that lipids shifted the fermentation type of FW from butyric to propionic acid *** on the estimated propionate production kinetic parameters,the maximum propionate productivity increased significantly with an increase in lipid content,reaching 6.23 g propionate/(L·d)at a lipid content of 50%.Propionate-producing bacteria Prevotella,Veillonella,and norank f Propionibacteriaceae were enriched in the presence of lipids,and the succinate pathway was identified as a prominent fermentation route for propionate ***,the Kyoto Encyclopedia of Genes and Genomes functional annotation revealed that the expression of functional genes associated with amino acid metabolism was enhanced by the presence of ***,these findings will contribute to gaining a better understanding of targeted propionate production from FW.

关键词： Acidogenic fermentation Microbial community Volatile fatty acid Propionate Foodwaste Lipid

Regression Function Comparison for Paired Data

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2020年第5期33卷 1558-1570页

作者： GUO xu ZHANG jun FANG Yun School of Statistics Beijing Normal UniversityBeijing 100875China College of Mathematics and Statistics Shenzhen UniversityShenzhen 518060China Department of Mathematics Shanghai Normal UniversityShanghai 200234China

In this paper,the regression function comparison for paired data is *** proposed test statistic is based on the weighted integral of characteristic function marked by the difference of *** are several merits of the proposed *** instance,it takes a simple V-statistic *** bandwidth is *** moment conditions are required for *** can be applied to covariates of any fixed *** asymptotic results are also *** is proven that n times the proposed test statistic converges to a finite limit under the null hypothesis and the test is consistent against any fixed *** alternative hypotheses which converge to the null hypothesis at the rate of n-1/2 are also detected.A suitable Bootstrap algorithm is also proposed for the implementation of the proposed test *** studies are carried out to illustrate the merits of the proposed method.A real data example is also used to illustrate the proposed testing procedures.

关键词： Bootstrap characteristic function paired data regression function comparison V-statistic

Solid-state NMR for metal-containing zeolites:from active sites to reaction mechanism

在线全文

学校读者我要写书评

暂无评论

Frontiers of Chemical Science and Engineering 2020年第2期14卷 159-187页

作者： Xingling Zhao jun xu Feng Deng National Center for Magnetic Resonance in Wuhan State Key Laboratory of Magnetic Resonance and Atomic and Molecular PhysicsCAS Key Laboratory of Magnetic Resonance in Biological SystemsWuhan Institute of Physics and MathematicsInnovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan 430071China University of Chinese Academy of Sciences Beijing 100049China Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China

Metal-containing zeolite catalysts have found a wide range of applications in heterogeneous *** understand the nature of metal active sites and the reaction mechanism over such catalysts is of great importance for the establishment of structure-activity *** advanced solid-state NMR(SSNMR)spectroscopy is robust in the study of zeolites and zeolite-catalyzed *** this review,we summarize recent developments and applications of SSNMR for exploring the structure and property of active sites in metal-containing ***,detailed information on host-guest interactions in the relevant zeolite catalysis obtained by SSNMR is also ***,we highlight the mechanistic understanding of catalytic reactions on metal-containing zeolites based on the observation of key surface species and active intermediates.

关键词： metal-containing zeolites solid-state NMR active site host-guest interaction reaction mechanism

Inventory Games with Quantity Discount

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 Science & Complexity 2021年第4期34卷 1538-1554页

作者： LI Wenzhong xu Genjiu SU jun School of Mathematics and Statistics Northwestern Polytechnical UniversityXi'an 710072China School of Science Xi'an University of Science and TechnologyXi'an 710054China

Meca,et al.(2004)studied a class of inventory games which arise when a group of retailers who observe demand for a common good decide to cooperate and make joint *** this paper,the authors extend their model to the situation where the manufacturer provides the retailers with a price discount on purchases in excess of a certain order *** authors define the corresponding inventory game with quantity discount,and show that the inventory game has a nonempty ***,the authors propose a core allocation rule,the demand-proportionality rule,and characterize it by introducing efficiency,the retailer splitting property and continuity.

关键词： Allocation cooperative games inventory model quantity discount

Genome editing in insects: current status and challenges

在线全文

学校读者我要写书评

暂无评论

National Science Review 2019年第3期6卷 399-401页

作者： jun xu Xia xu Shuai Zhan Yongping Huang CAS Key Laboratory of Insect Developmental and Evolutionary Biology CAS Center for Excellence in Molecular Plant Sciences Shanghai Institute of Plant Physiology and Ecology Chinese Academy of Sciences

Insects constitute the largest group in the animal kingdom, and include many economically important species as well as pests. This abundance provides largescale genetic resources, and research on insects is beneficial from the perspectives of human health, agricultural production and basic science (Fig.1).The availability of many genetic tools has made Drosophila melanogaster a crucially important model organism

关键词： Genome editing in insects current status and challenges