检索结果-南通市图书馆

I-sieve: An Inline High Performance Deduplication System Used in Cloud Storage

在线全文

学校读者我要写书评

暂无评论

Tsinghua science and Technology 2015年第1期20卷 17-27页

作者： Jibin Wang Zhigang Zhao Zhaogang Xu Hu Zhang Liang Li Ying Guo the Shandong Computer science Center (National Supercomputer Center in jinan) Shandong Provincial Key Laboratory of Computer Networks

Data deduplication is an emerging and widely employed method for current storage systems. As this technology is gradually applied in inline scenarios such as with virtual machines and cloud storage systems, this study proposes a novel deduplication architecture called I-sieve. The goal of I-sieve is to realize a high performance data sieve system based on i SCSI in the cloud storage system. We also design the corresponding index and mapping tables and present a multi-level cache using a solid state drive to reduce RAM consumption and to optimize lookup performance. A prototype of I-sieve is implemented based on the open source i SCSI target, and many experiments have been conducted driven by virtual machine images and testing tools. The evaluation results show excellent deduplication and foreground performance. More importantly, I-sieve can co-exist with the existing deduplication systems as long as they support the i SCSI protocol.

关键词： I-sieve cloud storage data deduplication

Fabrication processing effects on the microstructure and morphology of erbium film

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2012年第7期21卷 396-402页

作者：申华海彭述明龙兴贵周晓松杨莉刘锦华孙庆强祖小涛 Department of applied Physics University of Electronic Science and Technology of China Institute of nuclear Physics and Chemistry China Academy of Engineering Physics

The effect of substrate temperature on the microstructure and the morphology of erbium film are systematically investigated using X-ray diffraction （XRD） and scanning electron microscopy （SEM）. All the erbium films are grown by electron-beam vapor deposition （EBVD）. A novel preparation method for observing the cross-section morphology of the erbium film is developed. The films deposited at 200 ℃ have （002） preferred orientation, and the films deposited at 450 ℃ have a mixed （100） and （101） texture, due to the different growth mechanisms of surface energy minimization and recrystallization, respectively. The peak positions and the full widths at half maximum （FWHMs） of erbium diffraction lines （100）, （002）, and （101） shift towards higher angles and decrease with the increasing substrate temperature in a largely uniform manner, respectively. Also, the lattice constants decrease with increasing temperature. The transition in the film stresses can be used to interpret the changes in peak positions, FWHMs, and lattice constants. The stress is compressive for the as-growth fihns, and is counteracted by the tensile stress formed during the process of temperature cooling to room temperature. The tensile stress mainly originates from the difference in the coefficients of thermal expansion of the substrate-film couple.

关键词： erbium film substrate temperature preferred orientation columnar grain

Geometry dependent multipacting of a superconducting quarter-wave resonator at PKU

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2013年第7期37卷 58-61页

作者：周奎杨柳孙国平姚中元全胜文罗星鲁向阳 State Key laboratory of nuclear Physics and Technology Peking University Institute of applied Electronics Chinese Academy of Engineering Physics Institute of Modern Physics Chinese Academy of Science

A superconducting quarter-wave resonator （QWR） of frequency=162.5 MHz andβ=0.085 （β=v/c） has been designed at Peking University. The multipacting （MP） simulation and analysis for the QWR with CST Particle Studio has been performed. The simulation results reveal that there is no sign of MP with its normal operating accelerating gradients in the range of 6-8 MV/m. The accelerating gradient range that may incur MP is from about 1.4 to 3.2 MV/m, and the places where MP may be encountered are mainly located at the top part of the QWR. So the effect of different top geometries on MP has also been studied in depth. Our results show that an inward convex round roof is better than other round roofs, and plane roofs have an advantage over round roofs on the suppression of MP in general. While considering the optimization of its electromagnetic （EM） design, our initial designed model is also acceptable.

关键词： MP accelerating gradient range geometry growth rate

Eutectic-derived synthesis of hierarchically nanoporous copper for electrochemical actuation and solar steam generation

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第3期17卷 2011-2018页

作者： Qingguo Bai Yan Wang Fuquan Tan Zhonghua Zhang Key laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) School of Materials Science and EngineeringShandong UniversityJingshi Road 17923Jinan 250061China School of applied Physics and Materials Wuyi UniversityDongcheng Village 22Jiangmen 529020China School of Materials science and Engineering University of JinanWest Road of Nan Xinzhuang 336Jinan 250022China

The utilization of nanoporous copper(np-Cu)as a metallic actuator has gained attention in recent years due to its cost-effectiveness in comparison to other precious *** this,the enhancement of np-Cu’s actuation performance remains a challenge due to limitations in its strain amplitude and actuation ***,np-Cu has been deemed as a promising material for solar absorption due to its localized surface plasmon resonance ***,practical applications such as solar steam generators(SSGs)utilizing np-Cu have yet to be *** this study,we present the development of hierarchically nanoporous copper(HNC)through the dealloying of a eutectic Al-Cu *** hierarchical structure of the HNC features a combination of ordered flat channels and randomly distributed continuous nanopores,which work in synergy to improve actuation *** ordered flat channels,with a sub-micron scale,facilitate rapid mass transport of electrolyte ions,while the nano-sized continuous pores,due to their large specific surface area,enhance the induced *** results indicate that the HNC exhibits improved actuation performance,with a two times increase in both strain amplitude and rate in comparison to other reported ***,the HNC,for the first time,showcases excellent solar steam generation capabilities,with an evaporation rate of 1.47 kg·m^(-2)·h^(-1) and a photothermal conversion efficiency of 92%under a light intensity of 1 kW·m^(-2),which rivals that of nanoporous gold and silver *** enhanced actuation performance and newly discovered solar steam generation properties of the HNC are attributed to its hierarchically porous structure.

关键词： eutectic alloy dealloying hierarchically nanoporous copper(HNC) actuation solar steam generation

Defect stability in thorium monocarbide:An ab initio study

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 Physics B 2015年第9期24卷 424-429页

作者：王昌英韩晗邵宽程诚怀平 Shanghai Institute of applied Physics Chinese Academy of Sciences University of Chinese Academy of sciences Chinese Academy of sciences Key laboratory of nuclear Radiation and nuclear Energy Technology Chinese Academy of Sciences

The elastic properties and point defects of thorium monocarbide（ThC） have been studied by means of density functional theory based on the projector-augmented-wave method. The calculated electronic and elastic properties of ThC are in good agreement with experimental data and previous theoretical results. Five types of point defects have been considered in our study, including the vacancy defect, interstitial defect, antisite defect, schottky defect, and composition-conserving defect. Among these defects, the carbon vacancy defect has the lowest formation energy of 0.29 eV. The second most stable defect（0.49 eV） is one of composition-conserving defects in which one carbon is removed to another carbon site forming a C2 dimer. In addition, we also discuss several kinds of carbon interstitial defects, and predict that the carbon trimer configuration may be a transition state for a carbon dimer diffusion in Th C.

关键词： thorium monocarbide ab initio study bulk properties defects

CRACK IDENTIFICATION IN STEPPED CANTILEVER BEAM COMBINING WAVELET ANALYSIS WITH TRANSFORM MATRIX

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2009年第4期22卷 360-368页

作者： Weiwei Zhang Zhihua Wang Hongwei Ma College of science ＆ Engineering Jinan University Guangzhou 510632 China Institute of applied Mechanics Taiyuan University of Technology Taiyuan 030024 China The Key laboratory of Disaster Forecast and Control in Engineering Ministry of Education of China Jinan University Guangzhou 510632 China

This paper illustrates the crack identification method combining wavelet analysis with transform matrix. Firstly, the fundamental vibration mode was applied to wavelet analysis. The crack location was found by the peaks of the wavelet coefficients. Secondly, based on the identified crack locations, a simple transform matrix method requiring only the first two tested natural frequencies was used to further identify the crack depth. The present method can be used for crack identification in a complex structure. Numerical results of crack identification of a stepped cantilever beam show that the suggested method is feasible.

关键词： crack cantilever beam wavelet transform matrix

Irradiation Behavior in High Entropy Alloys

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2015年第10期22卷 879-884页

作者： Song-qin XIA Zhen WANG Teng-fei YANG Yong ZHANG State Key laboratory for Advanced Metals and Materials University of Science and Technology Beijing Institute for science and Technology Information and Strategy Central Iron and Steel Research Institute State Key laboratory of nuclear Physics and Technology Center for Applied Physics and TechnologyPeking University

As an increasing demand of advanced nuclear fission reactors and fusion facilities, the key requirements for the materials used in advanced nuclear systems should encompass superior high temperature property, good behavior in corrosive environment, and high irradiation resistance, etc. Recently, it was found that some selected high entropy alloys （HEAs） possess excellent mechanical properties at high temperature, high corrosion resistance, and no grain coarsening and self-healing abil- ity under irradiation, especially, the exceptional structural stability and lower irradiation-induced volume swelling, compared with other conventional materials. Thus, HEAs have been considered as the potential nuclear materials used for future fission or fusion reactors, which are designed to operate at higher temperatures and higher radiation doses up to several hundreds of displacement per atom （dpa）. An insight into the irradiation behavior of HEAs was given, including fundamental researches to investigate the irradiation-induced phase crystal structure change and volume swelling in HEAs. In summary, a brief overview of the irradiation behavior in HEAs was made and the irradiation-induced structural change in HEAs may be relatively insensi- tive because of their special structures.

关键词： high entropy alloy irradiation behavior self-healing structure change volume swelling

The vital application of rare earth for future high-performance electromagnetic wave absorption materials:A review

在线全文

学校读者我要写书评

暂无评论

Journal of Materials science & Technology 2024年第9期176卷 188-203页

作者： Jing Qiao Lutong Li Jiurong Liu Na Wu Wei Liu Fan Wu Zhihui Zeng Key laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) School of Materials Science and EngineeringShandong UniversityJinan 250061China School of Mechanical Engineering Shandong UniversityJinan 250061China Department of Chemistry and applied Biosciences ETH ZurichCH-8093 ZurichSwitzerland State Key laboratory of Crystal Materials Shandong UniversityJinan 250061China School of Mechanical Engineering Nanjing University of Science&TechnologyNanjing 210094China

Rare earth(RE)takes an irreplaceable role in various fields,especially the high-tech electronics industry,which is usually comparable to the vitamin of *** the development of electromagnetic wave(EMW)absorption materials,the participation of RE makes a significant contribution as well,and great progress has been *** researches have illuminated that the strategy of both doping RE elements and constructing RE oxide composites exhibited huge potential for the fabrication of high-efficiency EMW absorption *** believe a systematic summary will be highly desired for a comprehensive understanding and future *** this review,we first summarized the research background,basic principles,and mechanisms of EMW ***,we classify the RE EMW absorption materials into RE-doped ferrites,RE-transition metal intermetallics,RE oxides,and other categories,view their current progress by typical studies,and expound their respective features,strengths,weaknesses,and absorption ***,the current challenges and future outlook of RE EMW absorption materials are highlighted,in the hope of guidance for a sound future development.

关键词： Rare earth Electromagnetic wave absorption Composite Rare earth oxide

Estimation of Fracture Toughness for A508-III Steel in Ductile-to-Brittle Transition Region Using a Strain-Energy–Density-Based Fracture Failure Model

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

Acta Mechanica Solida Sinica 2022年第5期35卷 834-841页

作者： Yuanjun Wu Chen Bao Lixun Cai Kaiqing Wang Xiao Liu applied Mechanics and Structure Safety Key laboratory of Sichuan Province School of Mechanics and Aerospace EngineeringSouthwest Jiaotong UniversityChengdu610031China science and Technology on Reactor Fuel and Materials laboratory Nuclear Power Institute of ChinaChengdu610213China

According to the assumption of intrinsic relationship between ultimate strain energy density and microcrack nucleation,this work developed a fracture failure model to estimate the fracture toughness of A508-III steel in the ductile-to-brittle transition *** fracture toughness and uniaxial tension tests at different temperatures were carried out to determine the relationship between nucleation parameter and ultimate strain energy density,from which the evolutions of fracture toughness of A508-III ferritic steel for different cumulative failure probabilities at different temperatures were *** fracture failure model can well describe the fracture toughness distribution of A508-III steel in the ductile-to-brittle transition *** with the master curve method,this model has better temperature *** is more convenient to calibrate the parameters of this model compared with the traditional Beremin model,and without complex finite element analysis.

关键词： Fracture toughness Cumulative failure probability A508-III steel Ductile-to-brittle transition region