检索结果-南通市图书馆

Microstructure and mechanical properties of AZ91 magnesium alloy subject to deep cryogenic treatments

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9期20卷 896-901页

作者： Gui-rong Li Hong-ming Wang yun cai yu-tao Zhao Jun-jie Wang Simon P.A. Gill School of Materials Science & Engineering Jiangsu University The State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University Key Laboratory of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of Sciences Department of Engineering University of Leicester

AZ91 magnesium alloy was subjected to a deep cryogenic treatment. X-ray diffraction （XRD）, scanning electronic microscopy （SEM）, and transmission electronic microscopy （TEM） methods were utilized to characterize the composition and microstructure of the treated samples. The results show that after two cryogenic treatments, the quantity of the precipitate hardening β phase increases, and the sizes of the precipitates are refined from 8-10μm to 2-4μm. This is expected to be due to the decreased solubility of aluminum in the matrix at low temperature and the significant plastic deformation owing to internal differences in thermal contraction between phases and grains. The polycrystalline matrix is also noticeably refined, with the sizes of the subsequent nanocrystalline grains in the range of 50-100 nm. High density dislocations are observed to pile up at the grain boundaries, inducing the dynamic recrystallization of the microstructure, leading to the generation of a nanocrystalline grain structure. After two deep cryogenic treatments, the tensile strength and elongation are found to be substantially increased, rising from 243 MPa and 4.4% of as-cast state to 299 MPa and 5.1%.

关键词： magnesium alloys cryogenic treatment microstructure mechanical properties

在线全文

学校读者我要写书评

暂无评论

Ⅰ型神经纤维瘤病一家系基因检测

中国麻风皮肤病杂志 2024年第3期40卷 163-165页

作者：余佳琳梁嘉莉刘翌菲蔡妍张辰希张晓颖刘成李荣华广东省东莞市大朗医院皮肤科广东东莞523770 南方医科大学南方医院皮肤科广东广州510515 广州医科大学附属武警广东省总队医院皮肤科广东广州510517 福建医科大学附属泉州第一医院皮肤科福建泉州362000

目的:明确Ⅰ型神经纤维瘤病(neurofibromatosis type 1,NF1)一家系的致病基因。方法:本研究招募了一例NF1患儿,具有典型的皮肤咖啡牛奶斑、腋窝雀斑及神经纤维瘤。切除眼眶、上颚肿物行组织病理学和免疫组化检查,提取患儿及其家庭成员... 详细信息

目的:明确Ⅰ型神经纤维瘤病(neurofibromatosis type 1,NF1)一家系的致病基因。方法:本研究招募了一例NF1患儿,具有典型的皮肤咖啡牛奶斑、腋窝雀斑及神经纤维瘤。切除眼眶、上颚肿物行组织病理学和免疫组化检查,提取患儿及其家庭成员的外周血DNA,进行了全外显子组测序(Exome sequencing, WES)和Sanger测序。结果:结果显示眼眶、上颚肿物组织病理及免疫组化结果提示神经纤维瘤,在该NF1患儿中发现了一种新发致病性杂合突变NF1 c.204+2T>G,该突变导致氨基酸发生剪接突变。其父母无致病基因,该患儿为自发突变。结论:本研究鉴定一例NF1患儿的致病基因NF1 c.204+2T>G突变,丰富了NF1基因数据库。

关键词： Ⅰ型神经纤维瘤病 NF1基因突变

在线全文

学校读者我要写书评

暂无评论

大模型知识管理系统

中兴通讯技术 2024年第2期30卷 63-71页

作者：周扬蔡霈涵董振江南京邮电大学南京210023

企业知识管理至关重要,而传统企业知识管理系统存在构建成本高、知识利用率低的问题。提出了基于大模型检索增强生成(RAG)技术构建企业知识管理系统的方案。首先介绍了整体方案架构、业务流程与4类知识构建技术,然后重点介绍了检索前处... 详细信息

企业知识管理至关重要,而传统企业知识管理系统存在构建成本高、知识利用率低的问题。提出了基于大模型检索增强生成(RAG)技术构建企业知识管理系统的方案。首先介绍了整体方案架构、业务流程与4类知识构建技术,然后重点介绍了检索前处理、知识检索、检索后处理等全流程知识检索技术,并设计了全面的测评框架。经过实践检验,该方案具有知识构建效率高且成本低、意图理解精确、知识检索准确等特点与优势。

关键词： RAG 知识管理系统大模型知识工程

在线全文

学校读者我要写书评

暂无评论

北极东北航线钟摆运输模式

大连海事大学学报 2024年第2期50卷 11-22页

作者：李振福高瑞阳蔡梅江大连海事大学交通运输工程学院辽宁大连116026

根据北极航运数据反映的变化规律,系统整理北极航运特点为:夏秋季节通航,航运量受外部条件制约,航运结构单一,以外部运输为主。在此基础上,提出运输时间、运输复杂度和运输范围均更适合北极航运的钟摆运输模式,从支点港口、船型和模块... 详细信息

根据北极航运数据反映的变化规律,系统整理北极航运特点为:夏秋季节通航,航运量受外部条件制约,航运结构单一,以外部运输为主。在此基础上,提出运输时间、运输复杂度和运输范围均更适合北极航运的钟摆运输模式,从支点港口、船型和模块化运输三个方面进行北极东北航线钟摆运输模式设计,并比较分析钟摆运输模式与传统运输模式和混合运输模式的全年航运收益。结果表明:北极东北航线钟摆运输模式相比其他两个运输模式,每年可多完成一个航次,年航运收益分别增加9%和11.3%。

关键词：北极东北航线航运模式成本效益分析

Elastic Scattering Properties of Ultracold Strontium Atoms

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2011年第12期28卷 110-112页

作者： ZHANG Ji-cai ZHU Zun-Lue LIU yu-Fang SUN Jin-Feng College of Physics and Information Engineering Henan Normal UniversityXinxiang 453007 Department of Physics Luoyang Normal CollegeLuoyang 471022

We investigate the elastic scattering properties of strontium atoms at ultracold *** scattering parameters,such as s-wave scattering lengths,effective ranges and p-wave scattering lengths,are calculated for all stable isotope combinations of Sr atoms by the quantal method and semiclassical method,*** agreements are *** scattering parameters are very sensitive to small changes of the reduced *** to the repulsive interisotope and intraisotope s-wave scattering length and large elastic cross sections,84Sr–86Sr mixture is a good candidate to realize Bose–Bose quantum degenerate atomic gases.

关键词： wave Elastic degenerate

新疆阿克苏和吐鲁番地区硬蜱中3种立克次体检测及遗传进化分析

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

动物医学进展 2024年第7期45卷 42-47页

作者：温丽翠李才善周娜赵珊珊石文玉普浩刘诗语伍军巴音查汗新疆农业大学动物医学学院新疆乌鲁木齐830052

分析采自新疆阿克苏(SY)和吐鲁番(ADH)两地共132只蜱样本,研究蜱与其携带共生菌、病原三者之间的遗传进化关系。提取单个蜱总DNA,采用PCR方法对132份DNA样品进行无浆体16S rRNA基因扩增检测,挑选7份阳性样本基于COI基因进行分子生物学鉴... 详细信息

分析采自新疆阿克苏(SY)和吐鲁番(ADH)两地共132只蜱样本,研究蜱与其携带共生菌、病原三者之间的遗传进化关系。提取单个蜱总DNA,采用PCR方法对132份DNA样品进行无浆体16S rRNA基因扩增检测,挑选7份阳性样本基于COI基因进行分子生物学鉴定;使用MEGA X构建系统发育树,采用DNA SP V5.0软件统计两地蜱单倍型的数量,计算突变位点和核甘酸多样性。经PCR检测发现蜱无浆体总感染率为34.8%(46/132);测序结果发现SY1为图兰扇头蜱(46/132),携带斑点热立克次体,SY2、SY3及SY4为亚洲璃眼蜱,其中SY2、SY3携带*** sp.,SY4携带嗜吞噬细胞无浆体;ADH1、ADH2及ADH3为小亚璃眼蜱,ADH1携带绵羊无浆体,ADH2、ADH3携带*** sp.。构建系统发育树分析发现,ADH2、ADH3、SY2、SY3中鉴定出的Candidatus Midichloria mitochondrii sp.(*** sp.),与意大利株***同源性较高聚为一支,SY4中鉴定出的Anaplasma sp.与新疆株嗜吞噬细胞无浆体聚为一支,ADH1中鉴定的Anaplasma sp.与意大利株绵羊无浆体聚为一支;SY1与斑点热立克次体表现出较近的亲缘关系;单倍型结果分析显示,***单倍型数量为2,突变位点为4,核酸多样性为0.00408。***单倍型数量为3,突变位点为3,核酸多样性为0.00303,两个地区亚洲璃眼蜱和小亚璃眼蜱的基因流动性较低。研究从亚洲璃眼蜱和小亚璃眼蜱中均检测出*** sp.,可为后续蜱-蜱传疾病-共生菌三者之间的关系提供理论基础。

关键词：蜱传疾病共生菌进化分析

Teaching mechanism empowered by virtual simulation: Edge computing–driven approach

在线全文

学校读者我要写书评

暂无评论

Digital Communications and Networks 2023年第2期9卷 483-491页

作者： Ziqiao Wang Xiaomu cai Yanbian University Yanji133000China

With the rapid development of network and communication techniques,the teaching forms have become *** enhance the education experience and improve the teaching environment,an increasing number of educational institutions have adopted virtual simulation technology.A typical teaching mechanism is to exploit Virtual Reality(VR)technology,which affords participants an immersive ***,such a VRbased mode is highly ***,the performance of this technology requires further *** one hand,for VR 360video,the current intraframe decision cannot adapt to rapid response *** the other hand,the generated data size is considerably large and fast computation may not be realized,depending on the local VR ***,this study proposes an improved teaching mechanism empowered by edge computing–driven VR,called VE4T,that involves two ***,an intraframe decision algorithm for VR 360videos is devised to realize the rapid ***,an edge computing framework is proposed to offload some tasks to an edge server for computation,where a task scheduling strategy is developed to check whether a task needs to be ***,experiments are performed using a practical teaching scenario with some VR *** obtained results demonstrate that VE4T is more efficient than existing mechanisms.

关键词： Virtual reality Edge computing Immersive experience Scheduling strategy Intraframe decision

一种具有纹波消除技术的10 bit SAR ADC

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

半导体技术 2024年第4期49卷 350-359页

作者：李硕蔡孟冶姜岩峰江南大学物联网工程学院电子工程系先进技术研究院江苏无锡214122

逐次逼近寄存器模数转换器(SAR ADC)在逐次逼近的过程中,电容的切换会使参考电压上出现参考纹波噪声,该噪声会影响比较器的判定,进而输出错误的比较结果。针对该问题,基于CMOS 0.5μm工艺,设计了一种具有纹波消除技术的10 bit SAR ADC... 详细信息

逐次逼近寄存器模数转换器(SAR ADC)在逐次逼近的过程中,电容的切换会使参考电压上出现参考纹波噪声,该噪声会影响比较器的判定,进而输出错误的比较结果。针对该问题,基于CMOS 0.5μm工艺,设计了一种具有纹波消除技术的10 bit SAR ADC。通过增加纹波至比较器输入端的额外路径,将参考纹波满摆幅输入至比较器中;同时设计了消除数模转换器(DAC)模块,对参考纹波进行采样和输入,通过反转纹波噪声的极性,消除参考纹波对ADC输出的影响。该设计将信噪比(SNR)提高到56.75 dB,将有效位数(ENOB)提升到9.14 bit,将积分非线性(INL)从-1~5 LSB降低到-0.2~0.3 LSB,将微分非线性(DNL)从-3~4 LSB降低到-0.5~0.5 LSB。

关键词：模数转换器(ADC) 参考纹波消除信噪比(SNR) 有效位数(ENOB) 积分非线性(INL) 微分非线性(DNL)

Recent progress in the interaction between energetic particles and tearing modes

在线全文

学校读者我要写书评

暂无评论

National Science Review 2022年第11期9卷 240-261页

作者： Huishan cai Ding Li Chinese Academy of Sciences Key Laboratory of Geospace Environment School of Nuclear Sciences and TechnologyUniversity of Science and Technology of China Institute of Physics Chinese Academy of Sciences Songshan Lake Materials Laboratory

The dynamics of energetic particles and tearing modes and the interactions between them are of great significance for magnetically confined fusion plasmas. In this review, we focus on these issues in the context of tokamak plasmas. The interaction between energetic particles and tearing modes is considered from two perspectives:(i) the influence of energetic particles on tearing modes and(ii) the transport of energetic particles by tearing modes. The influence of energetic particles on tearing modes is described on the basis of a general dispersion relation for tearing modes. The effects of energetic particles are considered separately in the outer region and the island region of a tearing mode. The physics mainly results from the modification of the perturbed parallel current by energetic particles without wave–particle resonance. In addition, the resonance between energetic particles and tearing modes is also reviewed. For the transport of energetic particles, transport of both circulating and trapped energetic particles by tearing mode is reviewed. Our descriptions of physical phenomena here are based on an analytical approach, while the experiments and simulations are used to illustrate and confirm our results. Finally, a number of open issues are discussed.

关键词： magnetically confined plasma energetic particle tearing mode transport confinement tokamak