检索结果-南通市图书馆

同方期刊数据库

k9光学元件的锥形约束射流抛光流场与加工实验研究

在线全文

学校读者我要写书评

暂无评论

高技术通讯 2024年第3期34卷 320-330页

作者：袁巧玲王玥文东辉孔凡志郭旭特种装备制造与先进加工技术教育部/浙江省重点实验室杭州310023 浙江工业大学机械工程学院杭州310023

提出了锥形约束射流抛光的加工方法,将原本垂直的细小射流约束成几乎平行于工件表面的环形射流。使用Fluent软件对抛光流场进行数值分析,根据Preston方程建立了材料去除函数模型;并以k9玻璃为加工对象,利用自主设计的锥形约束射流抛光... 详细信息

提出了锥形约束射流抛光的加工方法,将原本垂直的细小射流约束成几乎平行于工件表面的环形射流。使用Fluent软件对抛光流场进行数值分析,根据Preston方程建立了材料去除函数模型;并以k9玻璃为加工对象,利用自主设计的锥形约束射流抛光平台进行加工实验。结果表明,锥形约束射流抛光方法法向最大速度比切向最大速度小63.9%,从而减少射流在垂直于工件表面方向的冲击损伤;锥形约束射流抛光后,k9玻璃表面粗糙度在加工区域内呈“V”型分布,其算数平均粗糙度(Ra)值从95.40 nm降至14.52 nm,表面质量得到明显提高。锥形约束射流抛光主要依靠射流沿工件表面的剪切力,不仅有效减小了射流法向冲击力,对射流的约束还减小了射流束的发散;确定的表面去除函数表明该方法有望实现确定性抛光;另外,环形的射流出口提高了射流抛光的效率。

关键词：锥形约束冲击损伤表面粗糙度 k9玻璃去除函数

Majorana gets an iron twist

在线全文

学校读者我要写书评

暂无评论

National Science Review 2019年第2期6卷 196-197页

作者： Lingyuan kong Hong Ding Institute of Physics Chinese Academy of Sciences

A magical coincidence of condensedmatter physics occurred in *** February of that year,a new kind of high-Tc（26 k）superconductivity was reported in the fluorine-doped iron-basedsuperconductor（FeSC） La[O1-xFx]FeAs[1],starting the ‘Iron Age’ of *** the following April,a 3D topological insulator（TI）was verified in Bi–Sb alloy[2],triggering a worldwide wave of searching for more

关键词： ARPES Majorana gets an iron twist MBS

Fixed-parameter tractability of capacitated k-facility location

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2023年第6期17卷 171-173页

作者： Xiangyan kong Zhen ZHANG School of Computer Science and Engineering Central South UniversityChangsha 410000China School of Frontier Crossover Studies Hunan University of Technology and BusinessChangsha 410205China Changsha Social Laboratory of Artificial Intelligence Changsha 410205China

1 Introduction In this paper we study the capacitated k-facility location(Capk-FL)*** instance I of the problem is specified by a set C of clients and a set F of facilities located in a metric space with distance function d,and a positive integer k,where ICI+[F|=n,each facility f eF is associated with a capacityμ(f)>0 and a facility-opening cost o(f)>0,and connecting a client c ∈ C to f incurs a client-connection cost that equals the distance from c to f.

关键词： client problem Fixed

甘肃河东夏季区域性短时强降水环流形势分类特征

在线全文

学校读者我要写书评

暂无评论

高原气象 2024年第2期43卷 329-341页

作者：孔祥伟李晨蕊杨秀梅杨毅杨晓军中国气象局兰州干旱气象研究所/甘肃省干旱气候变化与减灾重点实验室中国气象局干旱气候变化与减灾重点开放实验室甘肃兰州730020 兰州大学大气科学学院/兰州大学地球系统模式发展研究中心甘肃兰州730000 兰州中心气象台甘肃兰州730020

甘肃河东地区短时强降水易致灾,预报预警难度大。利用2010-2021年夏季加密观测站逐小时降水资料和NCEP/NCAR再分析资料,筛选出甘肃河东50次区域性短时强降水天气过程,基于这些天气过程的500 hPa位势高度距平场,使用k均值客观聚类分析和... 详细信息

甘肃河东地区短时强降水易致灾,预报预警难度大。利用2010-2021年夏季加密观测站逐小时降水资料和NCEP/NCAR再分析资料,筛选出甘肃河东50次区域性短时强降水天气过程,基于这些天气过程的500 hPa位势高度距平场,使用k均值客观聚类分析和主观天气学检验相结合的方法进行天气尺度环流形势分类,并通过合成分析和中尺度对流天气环境场条件分析方法构建不同类型的天气尺度系统配置概念模型。结果表明:(1)甘肃河东区域性短时强降水的天气尺度环流形势可分为高原槽东移型、副高边缘西南气流型、两高切变型和西北气流型四类。(2)副高边缘西南气流型引发的区域性短时强降水次数最多,两高切变型和高原槽东移型发生频率相当,西北气流型发生次数最少。(3)四种类型的环流形势在天气系统配置、抬升条件、水汽条件和不稳定条件等方面存在显著差异。高原槽东移型、副高边缘西南气流型、两高切变型三种类型发生时西太平洋副热带高压(以下简称西太副高)所处的位置逐渐向西向北推进,水汽条件和不稳定条件逐渐趋好,当高空槽引导冷空气东移南下,斜压锋生形成大范围短时强降水。高原槽东移型抬升条件最好,短时强降水落区偏南;两高切变型冷空气偏北且主要由对流层低层侵入,短时强降水落区偏北;副高边缘西南气流型冷暖气团交汇最剧烈,斜压锋生最强,短时强降水范围及强度也更大。西北气流型的动力条件和水汽条件是四类中最差的,但强烈的中高层干冷平流叠加低层暖湿气流或温度暖脊形成了四类中最好的不稳定条件,短时强降水落区较分散。

关键词：甘肃河东地区短时强降水天气尺度环流形势聚类分析概念模型

同方期刊数据库

高含水气液两相流中水合物成核—生成—堵塞规律研究

在线全文

学校读者我要写书评

暂无评论

中国造船 2024年第3期65卷 151-163页

作者：孔庆文牟婕季鹏庞振力张剑波王志远中国石油大学(华东)石油工程学院青岛266580 中石化天然气分公司山东实华天然气有限公司青岛266061 中国石油集团海洋工程有限公司天津分公司天津300451 油气钻完井技术国家工程研究中心青岛266580

在海域水合物开采和深水油气钻井过程中,排水管线和井筒中易出现高含水气液两相流。在低温高压的环境中水合物在管线中生成后会出现聚集、沉积等情况,严重时会形成堵塞,威胁生产安全。基于自主搭建的高压流动环路进行试验,探究高含水条... 详细信息

在海域水合物开采和深水油气钻井过程中,排水管线和井筒中易出现高含水气液两相流。在低温高压的环境中水合物在管线中生成后会出现聚集、沉积等情况,严重时会形成堵塞,威胁生产安全。基于自主搭建的高压流动环路进行试验,探究高含水条件下水合物成核、快速生成和堵塞阶段的特征,在不同初始流速和降温速率条件下分析宏观诱导时间、水合物生成量和堵塞时间的变化规律,建立了流动系统完全堵塞时水合物浓度的预测模型。结果表明,当初始流速在0.46~1.12 m/s范围内,宏观诱导时间和水合物堵塞浓度均随初始流速的升高先增大后减小,而随降温速率的增大而减小;水合物堵塞时间与初始流速呈正相关,而与降温速率呈负相关;在水合物成核和生成阶段,由传质主导转换为传热主导的特征流速为0.86±0.14 m/s;建立的水合物浓度预测模型的误差小于±15%。

关键词：水合物高含水体系流动环路试验水合物生成水合物堵塞浓度预测模型

Preparation of Pure Copper Powder from Acidic Copper Chloride Waste Etchant

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2008年第1期24卷 141-142页

作者： H.S.Hong M.S.kong J.k.Ghu J.k.Lee H.G.Suk Plant Engineering Center.Institute for Advanced Engineering Yongin 449-863 Korea Dept. of Advanced Mater. Eng. Korea Polytechnic University Shihung 429-793 Korea Nano-surface Treat. Tech. Team Korea Inst. of Industrial Technology Incheon 463-130 Korea Dept. of Mater. and Met. Eng. Kangwon National University Samcheok 245-711 Korea

The method for the recycling of copper from copper chloride solution was developed. This process consists of extraction of copper, purification and particle size reduction. In the first step, reductive metal scraps were added to acidic copper chloride waste enchants produced in the PCB industry to obtain copper powder. Composition analysis showed that this powder contained impurities such as Fe, Ni, and water. So, drying and purification were carried out by using microwave and a centrifugal separator. Thereby the copper powder had a purity of higher than 99% and spherical form in morphology. The copper powder size was decreased by ball milling.

关键词： Copper chloride liquid waste Printed circuit board (PCB), Liquid waste Highpurity copper powder

在线全文

学校读者我要写书评

暂无评论

导热吸波双功能粉体改性设计研究

中国塑料 2024年第6期38卷 19-24页

作者：高玮熊昌义韩飞孔泥早颜渊巍株洲时代新材料科技股份有限公司湖南株洲412007 湖南大学先进炭材料及应用技术湖南省重点实验室长沙410082

以氧化铝(Al_(2)O_(3))为导热粉体,铁硅铝(FeSiAl)为吸波粉体,采用十二烷基三乙氧基硅氧烷(C12)为粉体表面改性剂,设计不同配比及粒径的导热吸波双功能粉体,填充于硅油体系制备导热吸波垫片,开发出导热吸波双功能一体化材料。结果表明,... 详细信息

以氧化铝(Al_(2)O_(3))为导热粉体,铁硅铝(FeSiAl)为吸波粉体,采用十二烷基三乙氧基硅氧烷(C12)为粉体表面改性剂,设计不同配比及粒径的导热吸波双功能粉体,填充于硅油体系制备导热吸波垫片,开发出导热吸波双功能一体化材料。结果表明,C12对Al_(2)O_(3)、FeSiAl均具有良好的亲油改性效果;当Al_(2)O_(3)∶FeSiAl质量比为20∶80时,导热吸波垫片的导热系数最高可达到5.92 W/m·k,并在4.8~6.5 GHz区间拥有良好的吸波能力,在保证高导热的前提下,赋予复合材料优异吸波能力;此外,所制试样易于压缩,在50 psi压缩应力条件下即可达到50%压缩形变,便于实际装配应用。

关键词：导热吸波改性压缩

Metallic Sb-stabilized porous silicon with stable SEI and high electron/ion conductivity boosting lithium-ion storage performance

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 4234-4242页

作者： Jia-Guo Deng Hao-qin Feng Yu-Long Xu Si-Guang Guo Jian-Ping Li kai-Fu Huo Ji-Jiang Fu Biao Gao Pual-k.Chu The State key Laboratory of Refractories and Metallurgy and Institute of Advanced Materials and Nanotechnology Wuhan University of Science and Technology Wuhan National Laboratory for Optoelectronics (WNLO) School of Optical and Electronic InformationHuazhong University of Science and Technology Department of Physics Department of Materials Science & Engineeringand Department of Biomedical EngineeringCity University of Hong Kong

Silicon （Si） has mild discharge potential and high theoretical capacity,making it a highly desirable material for lithium-ion batteries （LIBs）.Nevertheless,the excessive volume expansion,poor ion/electron conductiv ity and unstable solid electrolyte interface （SEI） hinde practical application to ***,the metallic antimony（Sb） stabilized porous Si （SiDSb） composite was prepared by magnesiothermic reduction of Sb2O3and Mg2Si and chemical etching to remove the by-product of *** highly conductive Sb nanodots embedded in the Si liga ments promote not only the formation of conductive and stable LiF-rich SEI,but also the electron/ion transpor ability of *** to the outstanding bulk/interface stability,excellent conductivity,as well as ideal porous structure,the SiDSb electrode demonstrates a capacity of820 mAh·g-1after undergoing 320 turns at 1000 mA·***,it exhibits a stable capacity of 675 m Ah·g-1when tested at a higher current density of 5000 m A·*** results reveal a viable solution to solve three problems at the same time,namely the poor conductivity,inferior SEI and excessive volume expansion of Si,boding well for the design of Si-based materials for high-energy LIBs.

关键词： Anodes Antimony Lithium-ion batteries Silicon Solid electrolyte interphase

Pressure-controlled elliptical cavity expansion under anisotropic initial stress: Elastic solution and its application

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2016年第7期59卷 1100-1119页

作者： ZHOU Hang kong Gangqiang LIU HanLong College of Civil Engineering Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing University College of Civil and Transportation Engineering Key Laboratory of Ministry of Education for Geomechanics and Embankment EngineeringHohai University

This paper presents an elastic solution to the pressure-controlled elliptical cavity expansion problem under the anisotropic stress conditions. The problem is formulated by the assumption that an initial elliptical cavity is expanded under a uniform pressure and subjected to an in-plane initial horizontal pressure kσ_0 and vertical pressure σ_0 at infinity. A conformal mapping technique is used to map the outer region of the initial elliptical cavity in the physical plane onto the inner region of a unit circle in the phase plane. Using the complex variable theory, the stress functions are derived; hence, the stress and displacement distributions around the elliptical cavity wall can be obtained. Furthermore, a closed-form solution to the pressure-expansion relationship is presented based on the elastic solution to the stress and displacement. Next, the proposed analytical solutions are validated by comparing with the kirsch's solution and the finite element method(FEM). The solution to the presented pressure-controlled elliptical cavity expansion can be applied to two cases in practice. One is to employ the solution to the interpretation of the shear modulus of the soil or rocks and the in-situ stress in the pre-bored pressuremeter test under the lateral anisotropic initial stress condition. The other is the interpretation of the membrane expansion of a flat dilatometer test using the pressure-controlled elliptical cavity expansion solution. The two cases in practice confirm the usefulness of the present analytical solution.

关键词： elasticity pressure-controlled elliptical cavity expansion stress displacement pressuremeter test flat dilatometer test