检索结果-南通市图书馆

Key machining characteristics in ultrasonic vibration cutting of single crystal silicon for micro grooves

在线全文

学校读者我要写书评

暂无评论

Advances in Manufacturing 2019年第3期7卷 303-314页

作者： Jun-Yun Chen Tian-Ye Jin xi-chun Luo College of Vehicles and Energy Yanshan UniversityQinhuangdao 066004HebeiPeople's Republic of China Department of Design Manufacture and Engineering ManagementFaculty of EngineeringUniversity of StrathclydeGlasgow G11XJUK Center for Precision Engineering Harbin Institute of TechnologyHarbin 150001People's Republic of China

Structured complex silicon components have been widely used in solar cells,biomedical engineering and other industrial *** silicon is a typical brittle material,ultrasonic vibration cutting(UVC)is a promising method to achieve better cutting performance than conventional ***-frequency ID UVC possesses higher nominal cutting speed and material removal rate than many 2D/3D UVC systems,and thus,it has great development potential in industrial applications of structured silicon ***,few researchers have applied ID UVC to the cutting of structured silicon surfaces,since its main drawback is tool marks imprinted by the vibration on machined *** this study,to uncover the key machining characteristics under the condition of ID UVC,a series of tests involving diamond cutting grooves were first performed on the silicon *** machined surface and chips were subsequently measured and analyzed to evaluate the critical undeformed chip thickness,surface characteristics,and chip *** the main drawback of ID UVC,a novel theoretical model was developed for predicting the length of tool marks and evaluating the impact of tool marks on the surface *** results demonstrated that the critical undeformed chip thickness of silicon reached 1030 nm under a certain vibration amplitude and that an array of micro grooves was generated at the plastic region with a surface roughness(7?a)as low as 1.11 ***,the micro topography of the continuous chips exhibited discontinuous clusters of lines with diameters of dozens of nanometers,only composed of *** novel theoretical model was able to predict the length of tool marks with low ***,the impact of tool marks on the surface finish can be reduced and even eliminated with help of the model.

关键词： Ultrasonic vibration cutting(UVC) Single crystal Silicon Micro groove Chip Tool vibration mark

Characteristics of inclusions in high-Al steel during electroslag remelting process

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

International Journal of Minerals,Metallurgy and Materials 2012年第4期19卷 295-302页

作者： Cheng-bin Shi xi-chun Chen Han-jie Guo State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing Beijing 100083 China School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China Research Institute of High Temperature Materials Central Iron and Steel Research Institute Beijing 100081 China

The characteristics of inclusions in high-A1 steel refmed by electroslag remelting （ESR） were investigated by image analysis, scanning electron microscopy （SEM）, and energy-dispersive spectrometry （EDS）. The results show that the size of almost all the inclusions observed in ESR ingots is less than 5 μm. Inclusions smaller than 3 μm take nearly 75% of the total inclusions observed in each ingot. Inclu- sions observed in ESR ingots are pure AIN as dominating precipitates and some fine spherical Al2O3 inclusions with a size of 1 μm or less. It is also found that protective gas operation and slag deoxidation treatment during ESR process have significant effects on the number of inclusions smaller than 2μm but little effects on that of inclusions larger than 2 μm. Thermodynamic calculations show that AIN inclusions are unable to precipitate in the liquid metal pool under the present experimental conditions, while the precipitation of AlN inclusions could take place at the solidifying front due to the microsegregation orAl and N in liquid steel during solidification.

关键词： electroslag remelting aluminum nitride inclusions thermodynamics

Fluidization characteristics of different sizes of quartz particles in the fluidized bed

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2016年第3期13卷 584-591页

作者： Zi-Jian Wang Jun Tang chun-xi Lu State Key Laboratory of Heavy Oil Processing China University of Petroleum(Beijing)

Fluidization characteristics of quartz particles with different sizes are experimentally investigated in a fluidized bed with an inner diameter of 300 mm and height of 8250 *** show that the average solid holdup increases with the increase in superficial gas velocity and the decrease in initial solid holdup in the dense zone of the fluidized *** average cross-sectional solid holdup decreases with increasing bed height and superficial gas *** bed expansion coefficient increases with the increase in superficial gas velocity and the decrease in solid *** of average solid holdup,average cross-sectional solid holdup and bed expansion coefficient are also established and *** correlations can provide guidelines for better understanding of the fluidization characteristics.

关键词： Fluidization characteristic Solid holdup Axial average section solid holdup Bed expansion coefficient

Progress in Joining Ceramics to Metals

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2006年第2期13卷 1-5页

作者： ZHANG Yong FENG Di HE Zhi-yong CHEN xi-chun High Temperature Materials Research Institute Central Iron and Steel Research Institute Beijing 100081 China

The research and development of joining methods of ceramics to metals, especially brazing, diffusion bonding and partial transition liquid phase bonding, were introduced. Some opinions were put forward. For new composites emerging, it is necessary to develop new joining methods, particularly in the field of high temperature technique for joining ceramics to superalloys.

关键词： ceramic metal joining progress

Solvothermal Synthesis and Crystal Structure of Zn(en)_3B_5O_7(OH)_3

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2006年第3期22卷 271-273页

作者： HE Yi CHEN Wei YANG Jin xi chun-yu CHEN Jie-sheng State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of Chemistry Jilin University Changchun 130012 P. R. China

A new polyborate containing ehiral metal-complex Zn（en）3 B5O7（OH）3, where en = ethylenediamine, was synthesizedunder solvothermal conditions and structurally characterized by means of X-ray diffraction analysis. Crystal data： Zn（en）3 B5O7（OH）3, monoclinic, space group P21/c, a =0.8532（72） nm, b =2.3340（5） nm, c = 0.9526（92） nm, β =107. 04（3）°, Z=4, V=1.8140（6） nm^3, Dc =1.694 g/cm^3, p=1.416 mm^-1, F（000） = 960, GOF = 1. 020, R =0. 0276, Rw =0. 0828. There is a chiral Zn（en）3^2＋ complex cation and an isolated B5O7（OH）3^2- group in a Zn（en）3 B5O7（OH）3 molecule. The enantiomer of the chiral complex cation is separated orderly as ,4 and A configurations in the compound and the borate group consists of two B303 cycles linked through a bridging boron atom.

关键词： Solvothermal synthesis Crystal structure Chiral metal-complex Borate compound

Syntheses, Crystal Structures and Catalytic Activities of Two Novel Mn_2Dy_2O_2 Complexes

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2019年第1期38卷 109-116,4页

作者： ZHAO Guo-Qing LI Yan-xi CHEN Chang-Hui ZHANG chun-xi Laboratory of Photochemistry Institute of ChemistryChinese Academy of Sciences University of Chinese Academy of Sciences

Two novel heteronuclear manganese-dysprosium complexes have been synthesized and characterized, both of which contain a [Mn_2Dy_2O_2] core ligated by eight But CO_2-anions and four neutral ligands. In complex 1, [Mn_2Dy_2O_2(Bu^tCO_2)_8(Bu^tCO_2H)_4], all the four neutral ligands coordinated to Dy^(3+) are pivalic acids; Instead, two of these four pivalic acids have been replaced by ethanol in complex 2 [Mn2 Dy2 O2(Bu^tCO_2)_8(Bu^tCO_2H)_2(CH_3CH_2OH)_2]. The crystal of complex 1(C_(60)H_(112)Dy_2Mn_2O_(26), Mr = 1684.36) belongs to the orthorhombic system, space group Pbca with a =19.853(3), b = 18.565(3), c = 20.952(3) ?, V = 7723(2) ?3, Z = 4, Dc = 1.449 g/cm^3, S = 1.210, μ =2.302 mm^(-1), F(000) = 3448, the final R = 0.0802 and w R = 0.1570 for 8736 independent *** crystal of complex 2(C_(54)H_(104)Dy_2Mn_2O_(24), Mr = 1572.25) belongs to the monoclinic system,space group C2/c with a = 27.814(6), b = 13.194(3), c = 22.912(5) ?, β = 124.89(3)o, V = 6897(3) ?3,Z = 4, Dc = 1.514 g/cm^3, S = 1.086, μ = 2.570 mm^(-1), F(000) = 3208, the final R = 0.0256 and wR =0.0592 for 7763 independent reflections. The cyclic voltammogram and catalytic activity measurements of complex 1 suggest that this type of complex can serve as a catalyst for oxygen-evolving reaction.

关键词： manganese-dysprosium cluster crystal structure catalytic activity

Convenient synthesis of aryl-incorporated ditosylates and their application in preparation of crown ethers with higher yield

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2008年第8期19卷 911-914页

作者： Oi Zhong Zhou chun Lin He Hai Ning Gu Qi Ming Miao chun xi Zhai Department of Chemistry Zhejiang University Hangzhou 310027 China

A convenient synthetic method with high yields for aryl-incorporated ditosylates by reaction of aryl-incorporated diols with TsCI in THF/NaOH/H2O solution was described. Some of these aryl-incorporated ditosylates rea... 详细信息

关键词： Aryl-incorporated diol Ditosylate Crown ether

Scheduling piece requests blindly and randomly for peer-to-peer live streaming

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2010年第2期17卷 76-84页

作者： CHEN Yi-shuai CHEN Chang-jia ZHAO Yong-xiang LI chun-xi School of Electrical and Information Engineering Beijing Jiaotong University Beijing 100044 China

The design of piece scheduling algorithm is fundamental in mesh-based peer-to-peer （P2P） live streaming systems. This article regards the piece propagation process in P2P live streaming system as a conflict process, where peers compete to get the piece as soon as possible to meet the tight timing requirement of the live system. In this vision, the authors reduce the piece scheduling problem as a conflict resolution problem, and propose a blind random scheduling method to resolve it. The algorithm can be described as： 1） pieces are scheduled independently; 2） conflicts are resolved by the random back off algorithm. The theoretical analysis and simulation results prove that the algorithm scales well with the network size, and can obtain near-optimal in-time delivery of pieces. The algorithm is also easy to implement in the real-world system.

关键词： peer-to-peer live streaming conflict resolution exponential back off piece scheduling

First-Principles Study of Magnetic Properties of TM_(13) and TM_(13)@Au_(32) Clusters(TM = Mn, Co)

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2018年第10期35卷 22-26页

作者： Yi-Bo Li Li-Jin Zeng chun-xi＆ng Zhao chun-Yao Niu International Laboratory for Quantum Fhnctional Materials of Henan School of Physics and Engineering Zhengzhou UniversityZhengzhou 450001 School of Digital Media Shenzhen Institute of Information TechnologyShenzhen 518172

The structural and magnetic properties of TM13and TM_（13）@Au32clusters（TM=Mn,Co）are studied by firstprinciples *** find that the Au32cluster can tune not only the magnetic moment but also the magnetic coupling properties between the TM atoms of the TM *** Au32cluster can increase the net magnetic moment of Mn13clusters while reducing that of *** interaction between Au and Mn atoms induces more Mn atoms to form spin parallel coupling,resulting in an increase of the total magnetic moment of Mn13clusters,while for the Co13clusters,the interaction between Au and Co atoms does not change the magnetic coupling states between the Co atoms,but reduces the magnetic moment of the Co atoms,leading to a decrease of the total magnetic moment of this *** findings indicate that the encapsulation of Au32clusters can not only raise the chemical stability of TM clusters,but also can tune their magnetic coupling properties and magnetic moment,which enables such systems to be widely applied in fields of spintronics and medical science.

关键词： net Mn Clusters Au Co