插入化合物LiCo_（1－x）Ni_xO_2合成机构的研究

插入化合物ＬｉＣｏ_（１－ｘ）Ｎｉ_ｘＯ_２合成机构的研究林勤，陈宁，叶文（北京科技大学分析实验室北京１０００８３）刘人敏（北京有色金属研究总院北京１０００８８）锂离子电池是继镍氢电池后最新一代充电电池，其重量比能量是镍氢电池的１．５～２倍，具有工作电?..

滚齿机典型合成机构传动比的计算

滚齿机内联传动链的分析及调整与传动链的换置公式、合成机构的类型、具体结构密切相关。由于合成机构的传动比计算较复杂，给出绍了典型合成机构传动比的计算。

混合驱动内联系传动链中的运动合成机构分析

讨论了基于混合驱动的内联系传动链中可能应用的几种运动合成机构。二自由度周转齿轮系有两个输入运动和一个输出运动,故适合作为这种合成机构。其中2K-H型结构比较简单,是常用的二自由度周转齿轮系,本文讨论了其中3种类型的力矩平衡和功率平衡特征。获得结论为:2KH型的NGW负号机构能够满足运动合成机构的性能要求;2K-H型的WW正号机构在一定条件下能够满足性能要求;而滚齿机上常用的差速器机构通常不满足这种性能要求。

行星轮系机构的用例分析

以旋转表面光整加工所需的行星轮系机构为例,介绍了其传动系统图、速比关联图、合成线速度图,能为设计合理方案提供参考。

平面四杆机构的位置特性及其分类(英文)

提出机构位置特性新理论，将机构重合特性分为27种。并提出了重合判断的方法及参数值判断的程序框图。

Hydrothermal synthesis, characterization and optical properties of La_2Sn_2O_7:Eu^(3+) micro-octahedra

Pyrochlore structure La2Sn2O7：Eu3＋ microcrystals with uniform octahedron shape were successfully synthesized via a hydrothermal route at 180 °C for 36 h. The crystal structure, particle size, morphologies, and optical properties of the as-synthesized products were investigated by XRD, TEM, SEM, EDS, FT-IR, Raman spectroscopy and PL. The effects of pH of precursor solution, precursor concentration, reaction temperature, and time were investigated. The results reveal that pH of the precursor solution not only plays an important role in determining the phase of the as-synthesized products, but also has a significant influence on the morphologies of the samples. High-quality and uniform octahedrons with an average size of about 700 nm could be easily obtained at the pH value of 12. The possible formation mechanism of octahedral-like La2Sn2O7：Eu3＋ microcrystals was briefly proposed. The photoluminescence spectra show that La2Sn2O7：Eu3＋ micro-octahedra display stronger emission in the range of 582-592 nm compared with the samples with other shapes.

应用电化教学手段 提高教学质量

《金属切削机床》是机械制造工艺与设备专业的重要专业课.该课程实践性很强,特别是有些机床结构及工作原理比较复杂,虽然在讲课过程中大量使用幻灯片、挂图并辅之以现场参观等教学方法,但效果都不是很理想.有鉴于此,1994年8月在西安召开的全国高工专机械类专业协会会议上,机床液压课程组决定拍摄《齿轮加工机床》电视教学片,经公开招标最后决定由我校承担此片的制作任务.现在《齿轮加工机床》电教片已于1996年7月拍摄制作完成.

Preparation of tricalcium silicate and investigation of hydrated cement

Tricalcium silicate cement(TSC)has been widely used in dental materials because of its self-setting behavior,good bioactivity,biocompatibility,osteoinductivity,and antibacterial effect.Tricalcium silicate(C3S)powder was prepared by Pechini technique with a calcining temperature of 1300℃ for 3 h.The influence of liquid/powder(L/P)rate on the setting time and the mechanical property of TSC was studied.Characterization methods including XRD,FTIR,SEM-EDS,TEM,and ICP-AES were utilized to study the properties of C3S powder and its hydrated cement.The bioactivity and biocompatibility of the cement were investigated by soaking test and cell culture,respectively.The results show that the L/P rate plays an important role in the setting time and the compressive strength of TSC.The surface of TSC was covered by hydroxyapatite deposition during the immersion experiment and the cells attachment on the surface of TSC was well,which indicated that TSC has good bioactivity and biocompatibility.In addition,TSC has excellent antibacterial properties against Staphylococcus aureus.In conclusion,TSC is a promising candidate for root canal filling materials.

Synthesis and Crystal Structure of O,O-Dimethyl-N-(β-triphenylgermanyl)propionyl-α- aminobenzylphosphonates

The title compound (C30H32NO4PGe), O,O-dimethyl-N-(β-triphenylgermanyl) propionyl-α-aminobenzylphosphonates was synthesized by a convenient method, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal is triclinic, space group P-1 with parameters: a=9.7753(5), b=11.5773(5), c=13.5059(6) ?, α=104.185(1),β= 95.971(1), γ =96.727(1)°, V=1457.63(12) ?3, Z=2, Mr=574.13, Dc=1.308 g/cm3, λ=0.71073 ?, μ = 1.139mm-1, and F(000)=596. The structure was solved by direct methods. The structure was refined to R=0.0257, wR=0.0705 for 5080 observed reflections with I >2σ(I).The result of structure analysis indicates that atom Ge is sp3 hydridized because the arrangement of the four carbon atoms bonded to it is a distorted tetrahedron. The geometry of the three phenyl groups linking with the Ge atom looks like a propeller form.

Formation Mechanism and Binding Energy for Body-Centred Regular Octahedral Structure of Li7 Cluster

The formation mechanism for the body-centred regular octahedral structure of Li7 cluster is proposed. The curve of the total energy versus the separation R between the nucleus at the centre and nuclei at the apexes for this structure of Li7 has been calculated by using the method of Gou＇s modified arrangement channel quantum mechanics （MACQM）. The result shows that the curve has a minimal energy of-52.169 73 a.u. at R = 5.06ao. When R approaches infinity, the total energy of seven lithium atoms has the value of-51.996 21 a.u. So the binding energy of Li7 with respect to seven lithium atoms is 0.173 52 a.u. Therefore the binding energy per atom for Li7 is 0.024 79 a.u. or 0.674 eV, which is greater than the binding energy per atom of 0.453 eV for Li2, the binding energy per atom of 0.494 eV for Li3 and the binding energy per atom of 0.632 eV for Li5 calculated previously by us. This means that the Li7 cluster may be formed stably in a body-centred regular octahedral structure with a greater binding energy.

Synthesis and Structure of a New Dinuclear Molybdenum (I) Compound with Cyclohexanthiolate Ligand, [Mo_2(SC_6H_(11))_2(CO)_8]

Molybdenum(I) -compound [Mo2(SC6H11)2(CO)8]1,crystallizes in monoclinic,space group P21/c with a=9.5863(9),b=9.4469(9),c=13.869(1)A,β=99.697(2)°,V=1238.1(2)A^3,Z=2,Dc=1.734g/cm^3 ,μ=12.23cm^-1 and F(000)=644.The final R=0.0455 and wR=0.1159 for 1590 observed reflections with I>2ó(I).1 possesses a rhombic bimetallic core MoS2Mo with the Mo-Mo bond length of 2.975(1) and Mo-S of 2.485(2)A。

Preparation and Characterization of Organic/Inorganic Hybrid Nanofibers

A new class of nanocomposites based on organic and inorganic species integrated at a nanoscale has obtained more attention these years. Organic-inorganic hybrids have both the advantages of organic materials, such as light weight, flexibility and good moldability, and inorganic materials, such as high strength, heat stability and chemical resistance. In this work, PVAc/TiO2 organicinorganic hybrid was prepared by sol-gel process. Eiectrospinning technique was used to fabricate PVAc/TiO2 hybrid nanofibers. The structures and properties of the hybrid nanofibers were characterized by Scanning Electron Microscopy （SEM）, Atomic Force Microscope （AFM）, Differential Scanning Calorimeter （DSC） and Fouriertransform infrared （FTIR） spectra. SEM and AFM were employed to study the topography of the hybrid nanofibers. The chemical structure of the hybrid nanofibers were examined by FTIR. The DSC scans revealed the second order transition temperature of the hybrid materials were higher than PVAc.

Synthesis and Crystal Structure of (CH_2)_3(3,5-Me_2Pz)_2. [PhBr_2Sn(CH_2)SnBr_2Ph].2HBr.H_2O (Pz=pyrazole)

The reaction of bis(dibromophenylstannyl)methane with 1, 3-bis(3, 5-dimethyl- pyrazol-1-yl)propane in a 1:1 or 1:2 ratio yields only 1:1 adduct which partly hydrolyzes to the title complex (C26H38Br6N4O2Sn2, Mr = 1155.42) during crystal growing. The title complex is of triclinic, space group P with a = 10.886(1), b = 12.508(1), c = 13.879(1) ? = 85.762(2), = 85.159(2), = 84.020(2)? V = 1868.8(4) ?, Z = 2, Dc = 2.046 g/cm3, (MoK) = 0.71073 ? = 7.778 mm-1, F(000) = 1088, R = 0.0488 and wR = 0.1157 for 7560 observed reflections with I ≥ 2(I). The crystal structure analysis indicates that there is no direct interaction between the ligand and bis(dibromophenylstannyl)methane, and two tin atoms are bridged by two bromide atoms from the partial hydrolysis of this adduct.

Synthesis and Crystal Structure of 2-(Diphenylphosphine oxide)-3-(diphenylphosphine oxide ethynyl) spiro [bicyclo[2.2.1]hepta-2,5-diene-7,1'-cyclopropane]

The Diels-Alder reaction of bis(diphenylphosphine oxide)butadiyne (BDPPOB) with spiro[2.4]hepta-4,6-diene affords the title compound, 2-(diphenylphosphine oxide)-3-(diphen- ylphosphine oxide ethynyl)spiro[bicyclo[2.2.1] hepta-2,5-diene-7,1-cyclopropane] (DDSHC, C35H28O2P2, Mr = 542). Its crystal structure belongs to monoclinic system, space group P21/n with a =12.708(3), b = 14.666(4), c = 15.048(4) ? = 93.903(5) ? V = 2798.1(13) ?, Z = 4, Dc = 1.288g/cm3, F(000)=1136, (MoK? = 0.187mm-1, final R = 0.0626 and wR= 0.1422 for 4685 independent reflections with I > 2(I). Structural analyses reveal that the title compound is nonplanar and the dihedral angles between two phenyl rings around each phosphorus atom are 71.7(2) and 70.7(3)? respectively.

A Three-dimensional Organic-inorganic Hybrid Material Supported by Decavanadate Clusters and Na-O Chains: Synthesis and Crystal Structure of [Na_6(H_2O)_(16)(dod)_4V_(10)O_(28)]

A new organic-inorganic hybrid material [Na6(H2O)16(dod)2V10O28] (dod = 1,4- diazoniabicyclo[2,2,2]octane-1,4-diacetate) has been synthesized and X-ray single-crystal structural analysis reveals it crystallizes in triclinic, space group P with a = 11.533(7), b = 12.031(7), c = 12.187(4) ? a = 72.47(1), b = 73.16(1), g = 68.21(1)o, C20H64N4Na6O52V10, V = 1467(1) ?, Z = 1, Mr = 1840.1, Dc = 2.083 g/cm3, MoKa, l = 0.71073 ? m = 1.686, F(000) = 924, S = 1.027, the final R = 0.0538 and wR = 0.1272 for 4398 observed reflections. The compound has a three-dimensional frame- work constructed from decavanadate clusters, NaO chains and dod ligands. A variety of OH…O and CH…O hydrogen bonds play an important role in stabilizing the framework.

Voids' System in the Woven Composite Structure

Ccanposites are common material constructions for high-tech use now. Mechanical properties of woven reinforced composites are influenced by voids inside the structure. Voids could be classified to the two sections. Long and thin cracks are more dangerous than pores. It is important to find relations between preparation and place of occurrence of voids. This paper classifies defects according to rise mechanism, point of occurrence, orientation, size and affect to the properties. Image analysis was used for observing samples. Future work would be oriented not only to observing real samples, bet also to calculate mechanical properties frwn real and ideal structures in 3D woven reinforced composites.

Microstructure and synthesis mechanism of Al-Ti-C-Sr master alloy

Al-5Ti-0.5C-8Sr (mass fraction,%) master alloy was prepared using a melt reaction method.The microstructure and synthetic process of the master alloy were investigated by optical microscopy,X-ray diffraction,scanning electron microscopy and X-ray energy-dispersive spectrum.The results show that the master alloy is composed of α(Al),TiAl3,TiC,Al4Sr and Al-Ti-Sr phases.The synthesis mechanisms of the master alloy are as follows:TiAl3 is formed through the reaction between K2TiF6 and Al melt at 850 ℃;when the melt was heated up to 1 200?1 300 ℃,TiC was formed through the reaction:Ti+C(s)=TiC(s);Al4Sr was formed through the binary uniform reaction when Sr was added into the melt;after the following solidification process in the peritectic reaction:L(Al,Sr)+α(TiAl3)→β(Al-Ti-Sr),the enwrapped structure was formed with the outer layer of Al-Ti-Sr phase and the internal layer of TiAl3 phase.

Crystal Structure of A Novel Ionic Organotin Complex:{[Ph_(2)Sn]_(2)[2,6-(O_(2)C)_(2)C_(5)H_(3)N]_(3)H_(2)O}^(2-)[HNEt_(3)]_(2)^(+)

A novel ionic organotin complex{[Ph_(2)Sn]_(2)[2,6-(O_(2)C)_(2)]C_(5)H_(3)N}_(3)H_(2)O}^(2-)[HNEt_(3)]^(2+)has been unexpectedly obtained by the reaction of Ph_(3)SnCl and 2,6-pyridine dicarboxylic acid in 1:1 molar ratio in the presence of organic base Et_(3)N.Possible dephenylation mechanism was illustrated.The X-ray diffraction study has shown that the title complex consists of cation moiety[HNEt_(3)]^(+)and anion moiety{[Ph_(2)Sn]_(2)[2,6-(O_(2)C_(2))C_(5)H_(3)N]_(3)H_(2)O}^(2-)with tin(IV)in a pengonal bipyramidal coordination geometry.

Synthesis and structural characterization of a novel metal(Ⅱ)-organic complex based on imidazo[4,5-f]-1,10-phenanthroline

A novel metal（II）-organic complex Co（HIMP）（1,4-bdc）＇3H20 has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffxaction. The complex is a mononuclear Co（II） complex, which is assembled into a 3D supramolecular architecture via strong intermolecular π…π stacking interactions and hydrogen bonds.

THREE DIMENSIONAL DIGITIZATION OF HUMAN HEAD BY FUSING STRUCTURED LIGHT AND CONTOURS

Three dimensional digitization of human head is desired in many applications. In this paper, an information fusion based scheme is presented to obtain 3-D information of human head. Structured light technology is employed to measure depth. For the special reflection areas,in which the structured light stripe can not be detected directly, the shape of the structured light stripe can be calculated from the corresponding contour. By fusing the information of structured light and the contours, the problem of reflectance influence is solved, and the whole shape of head,including hair area, can be obtained. Some good results are obtained.