Systematic analysis of error sources during ultra-precision machining

0　ＩＮＴＲＯＤＵＣＴＩＯＮＰｒｅｃｉｓｉｏｎｄｅｓｉｇｎｉｎｖｏｌｖｅｓｄｅｓｉｇｎｏｆｍａｔｅｒｉａｌｓ ,ｍｅ ｃｈａｎｉｃｓ ,ｅｌｅｃｔｒｏｎｉｃｓ ,ｃｏｎｔｒｏｌ,ｔｈｅｒｍａｌ ｍｅｃｈａｎｉｃｓ ,ｄｙｎａｍ ｉｃｓａｎｄｓｏｆｔｗａｒｅａｎｄｅａｃｈｆａｃｔｏｒｍａｙｈａｖｅｓｏｍｅｅｆｆｅｃｔｏｎｔｈｅｆｉｎａｌｍａｃｈｉｎｉｎｇａｃｃｕｒａｃｙ[1] .Ｅｒｒｏｒｓｏｕｒｃｅｓｒｅｆｅｒｔｏｆａｃ ｔｏｒｓａｎｄｌｏｃａｔｉｏｎｓｔｈａｔｃａｎｐｒｏｄｕｃｅｍａｃｈｉｎｉｎｇｅｒｒｏｒｓ .…     

Electronic structures and properties of V, Nb and Ta metals

0　ＩｎｔｒｏｄｕｃｔｉｏｎＴｏｄｅｓｉｇｎａｌｌｏｙｓｓｃｉｅｎｔｉｆｉｃａｌｌｙ ,ｓｙｓｔｅｍａｔｉｃｓｃｉｅｎｃｅｆｒａｍｅｏｆｍｅｔａｌｓａｎｄａｌｌｏｙｓｉｎｃｌｕｄｉｎｇｔｈｅｓｙｓｔｅｍａｔｉｃｓｃｉｅｎｃｅｏｆｐｕｒｅｍｅｔａｌｓ (ｏｎｅ ａｔｏｍ (ＯＡ)ｔｈｅｏｒｙ) [1,2 ]ａｎｄｔｈｅｓｙｓ ｔｅｍａｔｉｃｓｃｉｅｎｃｅｏｆａｌｌｏｙｓ (ｃｈａｒａｃｔｅｒｉｓｔｉｃｃｒｙｓｔａｌ(ＣＣ)ｔｈｅ ｏｒｙ) [3～ 6 ]ａｒｅｅｓｔａｂｌｉｓｈｅｄ ,ｗｈｉｃｈｃａｎｇｉｖｅｄｉａｇｒａｍｓｏｆ…     

LanguageSciencesInEducation

ＬａｎｇｕａｇｅＳｃｉｅｎｃｅｓＩｎＥｄｕｃａｔｉｏｎＨｅＬｉ（ＤｅｐａｒｔｍｅｎｔｏｆＦｏｒｅｉｇｎＬａｎｇｕａｇｅ，ＫｕｎｍｉｎｇＩｎｓｔｉｔｕｔｅｏｆＴｅｃｈｎｏｌｏｇｙ，Ｋｕｎｍｉｎｇ６５００９３）ＬａｎｇｕａｇｅＳｃｉｅｎｃｅｓＩｎＥｄｕｃ...     

Mechanism and application of coal dry beneficiation with air-dense medium fluidized bed

Ｃｏａｌｄｒｙｂｅｎｅｆｉｃｉａｔｉｏｎｗｉｔｈａｉｒ－ｄｅｎｓｅｍｅｄｉｕｍｆｌｕｉｄｉｚｅｄｂｅｄｈａｓｂｅｅｎｅｓｔａｂｌｉｓｈｅｄａｓａｈｉｇｈｅｆｉ－ｃｉｅｎｃｙｄｒｙｓｅｐａｒａｔｉｏｎｔｅｃｈｎｉｑｕｅｗｈｉｃｈａｐｐｌｉｅｓｆｌｕ－ｉ...     

Alkylated and silylated β-cyclodextrin for gas chromatographic chiral stationary phases

1　ＩＮＴＲＯＤＵＣＴＩＯＮＷｉｔｈｔｈｅｄｅｖｅｌｏｐｍｅｎｔｏｆｌｉｆｅｓｃｉｅｎｃｅ ,ｓｅｐａｒａ ｔｉｏｎｏｆｅｎａｎｔｉｏｍｅｒｓｆｏｒｂｏｔｈａｎａｌｙｔｉｃａｌａｎｄｐｒｅｐａｒａ ｔｉｖｅｐｕｒｐｏｓｅｓｉｓａｎａｔｔｒａｃｔｉｖｅｔｏｐｉｃ     

Preparation and application of antimony mono (isooctyl thioglycolate) di(n-dodecanethiol)

ＡｎｔｉｍｏｎｙｍｅｒｃａｐｔｉｄｅｉｓａｎｅｗｔｙｐｅｏｆｈｅａｔｓｔａｂｉｌｉｚｅｒｆｏｒＰＶＣ,ｗｈｉｃｈｈａｓｔｈｅｆｏｌｏｗｉｎｇｃｈａｒａｃｔｅｒｉｓｔｉｃｓ：ｈｉｇｈｅｆｆｉｃｉｅｎｃｙ,ｎｏｎｔｏｘｉｃｏｒｈａｒｍｆｕｌｅｓ,ｌｏｗ...     

Influence of vibration on granular flowability and its mechanism of aided flow

Ｔｈｅｒｅａｒｅｍａｎｙｔｙｐｅｓｏｆｇｒａｎｕｌａｒａｉｄｅｄｆｌｏｗ ,ｉｎｗｈｉｃｈｖｉｂｒａｔｉｎｇａｉｄｅｄｆｌｏｗｉｓｗｉｄｅｌｙａｐｐｌｉｅｄｂｅ ｃａｕｓｅｏｆｉｔｓｐｒａｃｔｉｃａｌｉｔｙ ,ｃｏｎｖｅｎｉｅｎｃｅａｎｄｅｆｆｉｃｉｅｎ ｃｙ .Ｔｈｅｔｅｃｈｎｏｌｏｇｙｏｆｖｉｂｒａｔｉｎｇｏｒｅ ｄｒａｗｉｎｇｉｓｔｈｅａｐｐｌｉｃａｔｉｏｎｏｆｖｉｂｒａｔｉｎｇａｉｄｅｄｆｌｏｗｉｎｔｈｅｍｉｎｉｎｇｉｎｄｕｓｔｒｙ .Ｉｎ 1 957,ｔｈｅｆｉｒｓｔｖｉｂｒａｔｉｎｇｏｒｅ ｄｒａｗｉ…     

Nonlinear dynamic behavior of rubbing rotor under interaction between bending and torsional vibrations

0　ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｓｔｒｉｎｇｅｎｔｒｅｑｕｉｒｅｍｅｎｔｓｆｏｒｔｈｅｏｐｅｒａｔｉｏｎａｌｅｆｆｉ ｃｉｅｎｃｙｏｆｒｏｔａｔｉｎｇｍａｃｈｉｎｅｒｙｍａｋｅｓｔｈｅｒａｄｉａｌｃｌｅａｒａｎｃｅｂｅ ｔｗｅｅｎｒｏｔｏｒａｎｄｓｔａｔｏｒｓｍａｌｌｅｒａｎｄｓｍａｌｌｅｒｉｎｒｅｃｅｎｔｙｅａｒｓ ,ｔｈｅｒｅｂｙｉｎｃｒｅａｓｉｎｇｔｈｅｐｒｏｂａｂｉｌｉｔｙｆｏｒｔｈｅｒｏｔｏｒｔｏｒｕｂ .Ａｎａｌｙｓｉｓｏｆｖｉｂｒａｔｉｏｎａｌｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｒｕｂｂ…     

Starting of HPS lamps driven by electronic ballast

0　ＩＮＴＲＯＤＵＣＴＩＯＮＢｏｔｈｆｌｕｏｒｅｓｃｅｎｔａｎｄＨＩＤｌａｍｐｓａｒｅｂｅｃｏｍｉｎｇｐｏｐｕｌａｒｄｕｅｔｏｔｈｅｉｒｌｕｍｉｎｏｕｓｅｆｆｉｃｉｅｎｃｙａｎｄｑｕａｌｉｔｙｏｆｔｈｅｌｉｇｈｔｏｕｔｐｕｔ .Ｔｈｅａｐｐｌｉｃａｔｉｏｎｓｏｆｔｈｅｓｅｌａｍｐｓｒａｎｇｅｆｒｏｍｏｕｔｄｏｏｒｓｌｉｇｈｔｉｎｇｔｏｉｎｄｏｏｒｓｌｉｇｈｔｉｎｇ .Ｔｈｅｓｅｔｙｐｅｓｏｆｌａｍｐｓ,ａｌｔｈｏｕｇｈｔｈｅｙｈａｖｅｍａｎｙａｄ ｖａｎｔａｇｅｓｏｖｅｒｉｎｃａｎｄｅｓｃｅｎｔｌａｍ…     

BEHAVIOR OF OXYGEN IN DG TM INVAR Cu ALLOYS AND ITS EFFECTS ON MECHANICAL AND PHYSICAL PROPERTIES *

ＴｈｅＤＧＴＭｉｎｖａｒＣｕｌｏｗｅｘｐａｎｓｉｏｎａｎｄｈｉｇｈｃｏｎｄｕｃｔｉｖｉｔｙａｌｏｙｓｗｅｒｅｆｉｒｓｔｄｅｖｅｌｏｐｅｄｂｙｔｈｅＤｅｐａｒｔｍｅｎｔｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅａｎｄＥｎｇｉｎｅｅｒｉｎｇｏｆｔｈｅＣｅ...     

Environmental embrittlement of intermetallic compounds in Fe-Al alloys

First,it is proposed that hydrogen atoms occupy the interstitial sites in Fe3Al and FeAl.Then the environmental embrittlement of intermetallic compounds in Fe-Al alloys is studied in the light of calculated valence electron structures and bond energy of Fe3Al and FeAl containing hydrogen atoms.From the analyses it is found that the states of metal atoms will change,in which more lattice electrons will become covalent electrons to bond with hydrogen atoms when the atomic hydrogen diffuses into the intermetallic compounds in Fe-Al alloys,which will result in the decrease of local metallicity in Fe3Al and FeAl.Meanwhile,it is found that the crystal will easily cleave since solute hydrogen bonds with metal atoms and severely anisotropic bonds form.As a conclusion,these factors result in the environmental embrittlement of Fe3Al and FeAl.     

Atomic volumes and volume functions for Ag-Cu alloys

Ｔｈｅｔａｓｋｏｆａｌｌｏｙｄｅｓｉｇｎｉｓｔｏｐｒｏｄｕｃｅａｌｌｏｙｓｗｉｔｈｅｘｐｅｃｔｅｄｐｒｏｐｅｒｔｉｅｓｂｙｃｈｏｏｓｉｎｇｅｌｅｍｅｎｔｓａｎｄｔｈｅｉｒａｐｐｒｏｐｒｉａｔｅｐｒｏｐｏｒｔｉｏｎｓａｎｄａｄｏｐｔｉｎｇｒｅａｓｏｎａｂｌｅｗｏｒｋｉｎｇｌｉｎｅ,ｏｒｉｎｖｅｒｓｅｌｙ,ｔｏｐｒｅｄｉｃｔｐｒｏｐｅｒｔｉｅｓｏｆａｌｌｏｙｓａｃｃｏｒｄｉｎｇｔｏｔｈｅｅｌｅｍｅｎｔｓ,ｔｈｅｉｒｐｒｏｐｏｒｔｉｏｎｓａｎｄｓｔｒｕｃｔｕｒｅｓ.Ｔｈｅｓｅｔｗｏｉｎｖｅｒｓｅｐｒｏｃｅ…     

Interface structure of Ag (111)/SnO<Subscript>2</Subscript> (200) composite material studied by density functional theory

Electric contact material of Ag/SnO₂ was successfully synthesized by in situ process method. The interface structure was characterized by high-resolution transmission electron microscopy (HTEM) and simulated at atomic scale on computer. The mean-square displacements of atoms near the interface were calculated, and the results showed that near the interface both Ag side and SnO₂ were mismatched and this effect decays rapidly far from the interface. By inspecting the calculated density of states (DOS), we found that the electric-conductivity of this composite material was decreased because of the localized 4d and 2p electrons of Ag and O near the Fermi surface, respectively. Electron density changed acutely across the interface, so that there was no extra compound precipitated. A micro-electric field also formed in the whole material due to the interface structure, and this may affect the electron conduction and the related electric-conductivity of the composite. It is found that the interface cohesive energy of Ag (111)/SnO₂ (200) was −3.50 J/m², which is higher than the experimental results. Supported by the National Natural Science Foundation of China (Grant No. 2008CB617609), the Natural Science Foundation of Yunnan Province (Grant No. 2006E003Z) and Science Innovation Foundation of Kunming University of Science and Technology     

Cu/Ag催化剂水吸附性的第一性原理研究

目前非铂的合金催化剂已成为研究重点。Cu/Ag 合金通过各组分间的协同作用能够增强其催化活性,降低催化剂成本,有实际的应用价值。利用Material Studio软件进行Cu/Ag双金属的不同晶面结构的能带、态密度以及对水分子吸附能的研究,以确定不同晶面的催化活性。结果表明,当铜(Cu)在上、银(Ag)在下的layer 2结构,以及水分子吸附在铜原子还是吸附在银原子两种情况下,吸附能均为负值,吸附体系均稳定,表明该结构具有最好的电催化性能。     

Electrical conductivity of Cu-Li alloys

1　INTRODUCTIONCopperandcopperalloysarewidelyusedinelectricindustryduetotheirexcellentelectricalcon ductivity .ButtheimpuritiesandtraceelementsinCudecreasetheirelectricalconductivity ,especiallynon metalimpuritiessuchasoxygenandsulfurwhichaf fecttheirmechanicalproperties[14 ] .P ,MnandBecanbeusedasdeoxidant ,buttheresiduainCude creasetheelectricalconductivitydramatically[57] .ItwasreportedthatLicanrefinetheimpuritiesinCuandincreasethetensilestrengthofCuwithouttheelectricalconductivityd…     

La(Ni,Sn)5+x (x=0～0.35)贮氢合金的晶体结构与电化学性能

系统研究了La(Ni,Sn)_5+x（x=0~0.35) 无Co贮氢合金的化学计量比对其晶体结构及电化学性能的影响.X射线衍射分析仪（XRD）分析表明，上述合金均为单相CaCu₅结构.但在过计量比(x>0)合金的结构中，有部分1a位置元素（La）的原子被沿c轴定向排列的Ni-Ni“哑铃”对所替代，且其替代La原子的分数随x的增大而增多，从而导致合金晶胞的c轴及c/a比值明显增大，晶胞体积有所减小，并显著降低了合金的吸氢体积膨胀率.电化学测试表明，增大x值可使合金的循环稳定性得到显著提高，但也使合金的最大放电容量和高倍率放电性能有所降低.研究发现，由于合金的化学计量比增大会使其结构中含有较多的Ni-Ni“哑铃”对，合金的抗吸氢粉化能力得到了明显的改善，从而使合金在充放电过程中的反应比表面积有所减小、腐蚀速率得到抑制、循环稳定性得到显著提高.但合金反应比表面积的减小也导致了电极反应的速率的减小，从而使其高倍率放电性能有所降低.     

Phase diagram and thermodynamic properties of Ag-Cu alloys

Ｎｏｒｍａｌｌｙ,ｔｈｅａｌｌｏｙｐｈａｓｅｄｉａｇｒａｍｉｓｔｈｅｇｅｏｍｅｔｒｉｃａｌｄｅｓｃｒｉｐｔｉｏｎｏｆｔｈｅｒｅｌａｔｉｏｎｓｂｅｔｗｅｅｎｐｈａｓｅｓ,ｃｏｍｐｏｓｉｔｉｏｎｓａｎｄｔｅｍｐｅｒａｔｕｒｅｕｎｄｅｒｎｏｒｍａｌｐｒｅｓｓｕｒｅ.Ｔｈｅｔｅｃｈｎｏｌｏｇｙｏｆｃａｌｃｕｌａｔｉｎｇｐｈａｓｅｄｉａｇｒａｍｓｉｓｂａｓｅｄｏｎｔｈｅｒｍｏｄｙｎａｍｉｃｓｏｆａｌｌｏｙｓ,ｗｈｉｃｈｓｔｕｄｉｅｓｔｈｅｒｅｌａｔｉｏｎｓｂｅｔｗｅｅｎｖａｒｉｏｕｓｅｎｅｒｇｙｆａｃｔｏｒｓ…     

Electrochemical properties and structure of MlNi_(5-x)Sn_x system

The electrochemical properties and structure of M1Ni5-xSnx(x=0-0.5) hydrogen storage alloys were investigated by pressure-composition isotherms, electrochemical measurements, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and atomic parameters. With a small amount of tin substitution, the cycle life increases by 52% (0.5C) and 42% (1.0C), but maximum discharge capacity decreases only by 3.0% and 3.5%, respectively. The cycle life is obviously improved by the low volume expansion and the formed SnO2 surface layers upon electrochemical cycling. The substitution of Ni by Sn leads to an increase of the unit cell volume and charge-discharge cycle life and decrease of the plateau pressure, hysteresis and the hydrogen storage capacity. The standard enthalpy of hydride formation decreases with increasing tin substitution. The main factor that influences the standard enthalpy of the hydriding reaction is the number of the outer orbit electrons and not the atomic size factor.     

Synthesis of Ag@Cu_2O core-shell metal-semiconductor nanoparticles and conversion to Ag@Cu core-shell bimetallic nanoparticles

Ag@Cu2O core-shell metal-semiconductor nanoparticles(NPs) were prepared by using solution phase strategy. It was found that Ag@Cu2O core-shell NPs were easily converted to Ag@Cu bimetallic core-shell NPs with the help of surfactant PVP and excessive reducer ascorbic acid in air at room temperature, which is a unique phenomenon. Varying volumes of Ag colloidal solutions were added into the reaction mixtures containing fixed initial concentrations of Cu2+ and PVP, Ag@Cu2O and Ag@Cu core-shell NPs with fixed core size but varying outer shell thicknesses could be obtained. The composites, structures, morphologies and extinction properties of Ag@Cu2O and Ag@Cu core-shell NPs were systematically characterized by XRD, TEM and extinction spectra. Both of these NPs show wide tunable optical properties. The extinction peaks could be shifted from 421 nm to 700 nm. FTIR results reveal that Cu+ ions on the surface of Cu2 O nanocrystalline coordinate with N and O atoms in PVP and further are reduced to metallic Cu by excessive ascorbic acid and then form a nucleation site on the surface of Cu2 O nanocrystalline. PVP binds onto a different site to proceed with the reduction until all the Cu sources in Cu2 O NPs are completely assumed. And the shell of Cu2 O is converted to Cu shell. The synthesis approach in this paper is simple and also a promising reference for synthesizing other core-shell NPs. Ag@Cu2O NPs can be easily converted to Ag@Cu NPs in air at room temperature, which is promising to be used in electronic devices.     

基于递归法Cu-Zr合金的强化机理及导电性

为了研究Cu-Zr合金强化机理及导电性能,采用递归法计算Cu-Zr合金电子结构,并用电子结构参数解释了合金的强化与导电机理.研究发现,在Cu基体原子中Zr原子间相互作用能为正,互相排斥形成有序相,以化合物形式从基体析出.环境敏感镶嵌能的计算结果显示,稀土元素Y从晶粒内向晶粒表面扩散,并填补在生长中的Cu晶粒表面缺陷处,阻碍晶粒长大,使晶粒细化.Y在Cu晶粒表面互相排斥形成有序相,能阻止晶界或位错的运动,使合金的强度增加.电子的偏移使合金原子带负电荷,而周围的Cu基体带正电荷,进而在合金内部产生微电场.微电场的存在对电子产生散射作用,使合金电阻增大,降低导电能力.