泡生法生长大尺寸蓝宝石单晶的等径控制方法

在泡生法生长大尺寸蓝宝石单晶的过程中,为了获得高质量的晶体,精确等径控制至关重要.本文根据晶体的重量变化率来控制热场,实现晶体等径生长.设计了应用在线整定多项式权值的广义最小方差(OAPW_GMV)控制方法,并建立了系统模型.该方法的主要思想是根据在线估计的被控对象参数及OAPW_GMV的输出,调整多项式的权值,实现炉内的热场控制.仿真和实验结果表明该控制方法实现了蓝宝石单晶的精确等径控制,有效地提高了蓝宝石单晶的质量.     

用等离子体辅助分子束外延生长氧化锌单晶薄膜

利用等离子体辅助分子束外延(P-MBE)方法,通过优化生长条件,在c平面蓝宝石(Al_2O_3)上生长出氧化锌(ZnO)单晶薄膜。使用反射式高能衍射仪(RHEED)原位监测到样品表面十分平整,X射线摇摆曲线(XRC)测得ZnO薄膜的<002>取向半峰全宽为0.20°,证实为ZnO单晶薄膜。室温下吸收谱(ABS)和光致发光(PL)谱显示了较强的激子吸收和发射,且无深能级(DL)发光。电学性能测量表明,生长的ZnO为n型半导体,室温下载流于浓度为7×10~(16) cm~(-3),与体单晶ZnO中的载流子浓度相当。     

助熔剂法和浮区法生长Nd_(2-x)Ce_xCuO_4单晶及其热传导研究北大核心CSCD

本文研究了用助熔剂法和浮区法两种方法生长Nd2-x Cex CuO4(NCCO)单晶的生长条件和NCCO单晶的热传导性质.用助熔剂法方法可以生长出组份为x=0至x=0.18的一系列单晶样品.用X射线衍射表征了单晶的结构和品质,并观测了不同的退火过程对样品的超导转变的影响.在浮区法方面,生长NCCO(x=0.15)单晶也取得了很好的结果.另外,本文还测量了不同组份的单晶样品的低温热导率,发现Nd3+离子磁性对热导率的影响以及掺杂Ce后热导率的变化情况.     

Syntheses and Structures of Three Cobalt Metal-organic Frameworks with 3-（Sulfonyl-glycine）benzoic Acid

Three new coordination networks based on a versatile and unsymmetric building block 3-（sulfonyl-glycine）benzoic acid （HAL） ligand and inorganic Co（Ⅱ） salt, [Co（HL）（bipy）2]. ClO4·1.5H2O （1）, [Co3（L）2（H2O）6]·4H2O （2） and [Co（HL）（bpp）（H2O）2]·2H2O （3） （bipy = 2,2-bipyridine, bpp = 1,3-bi（4-pyridyl）propane）, have been synthesized in aqueous media and structurally characterized by single-crystal X-ray diffraction. Reaction of Co salt with H3L afforded a neutral 1D alternating chain, which shows a 3-D supramolecular network through hydrogen bonds. When the auxiliary 2,2-bipyridine is used, a mononuclear unit is constructed; if using auxiliary ligand bpp, a neutral 1-D uniform chain is obtained and further extended into a 3-D supramolecular structure through versatile hydrogen bonds. The H3L ligand in 1 adopts a bidentate chelating coordination mode while that in 2 and 3 assumes a pentadentate bridging and a bis-monodentate bridging modes, respectively. This work and our previous work evidently demonstrate that the structures vary with altering the second ligands.     

Synthesis and Structure of a POMs-based 3D Zeolike Ionic Crystal, {[Co（dpdo）2（H2O）2（CH3CN）]2（SiMo12O40）（H2O）2}n

A POMs-based 3D zeolike ionic crystal 1, {[Co（dpdo）2（CH3CN）（H2O）2]2（SiMo12O40）- （HEO）2}n （dpdo = 4,4＇-bipyridine-N,N＇-dioxide）, was constructed via self-assembly by embedding Keggintype [SiMo12O40]^4- polyanions within the intercrystalline voids as pillars and structurally characterized. The crystal structure was determined by single-crystal X-ray diffraction. The crystal is of triclinic, space group P1 with a = 11.430（3）, b = 12.242（3）, c = 14.279（3）A, α = 106.196（4）,β = 94.316（4）, γ = 98.294（3）°, V = 1884.5（7）A^3 Z = 1, C44H50N10O54CoEMo12Si, Mr = 2880.17, Dc = 2.538 g/cm^3, p = 2.484 mm^-1,F（000） = 1388, the final R = 0.0383 and wR = 0.1096 for 7753 observed reflections with I 〉 2σ（I）. Flack factor is 0.22（3）. Compound 1 is a pillar-layered framework with the [SiMo12O40]^4- anions linearly located on the square voids between the 2D bilayers which are formed by the dpdo ligands and cobalt（II） ions.     

Synthesis and Crystal Structure of a New Macrocycle Based on Diethoxycarbonyl Glycoluril: C_(26)H_(30)N_6O_(10)

A new macrocycle based on diethoxycarbonyl glycoluril 3,C26H30N6O10,has been synthesized and characterized by single-crystal X-ray diffraction. It crystallizes in monoclinic,space group P21/c with a = 12.7291（10）,b = 25.157（2）,c = 8.5489（7） A,β = 104.4760（10）°,V = 2650.7（4） A^3,Z = 4,C26H30N6O10,Mr = 586.56,F（000） = 1232,T = 292（2） K,Dc = 1.470 g/cm^3,μ = 0.115 mm^-1,the final R = 0.0590 and wR = 0.1299 for 4918 observed reflections with I 〉 2σ（I）. In the structure of the title compound,a three-dimensional microporous architecture is formed via intermolecular hydrogen bonding interactions.     

Synthesis and Structure of a New Mixed-polyoxometalate （W/Mo） Compound： H5K{[Co（H2O）5]2（H2Mo3.24W8.76O42）}·19H2O

One new polyoxometalate compound connected via cobalt/potassium cations,namely H5K{[Co（H2O）5]2（H2Mo3.24W8.76O42）}·19H2O 1,was prepared and characterized by ele- mental analysis and IR spectroscopy. Single-crystal X-ray diffraction analysis result reveals that anions of {[Co（H2O）5]2（H2Mo3.24W8.76O42）}6- in compound 1 are linked by potassium cations to form one- dimensional chain,based on which a three-dimensional network is further constructed with the help of hydrogen bonds. Crystal data： H67Co2KMo3.24O72W8.76,Mr = 3297.87,monoclinic,C2/c,a = 19.0126（10）,b = 16.6025（5）,c = 19.1908（10）A,β = 106.713（1）°,V = 5801.8（5） A^3,Z = 4,Dc = 3.755 g/cm^3,F（000） = 5961,μ = 18.730 mm^-1,R = 0.0569 and wR = 0.1437 （I 〉 2σ（I））.     

Synthesis and Crystal Structure of a New Dimolybdenum（V） Complex Na4[Mo2O4（HNTA）2]2·19H2O

The new binuclear molybdenum（V） complex Na4[Mo2O4（HNTA）2]2·19H2O （NTA = nitrilotriacetate） has been prepared and characterized by single-crystal X-ray diffraction analysis and IR. The crystal has space group Pnma with a = 10.2239（2）,b = 23.8174（3）,c = 23.1845（4） A,V = 5645.58（16）A^3,Z = 4,C24H66Mo4N4Na4O51,Mr = 1702.50,Dc = 1.958 g/cm^3,μ = 1.027 mm^-1,F（000） = 3280,T = 293（2） K,the final R = 0.0609 and wR = 0.1449 for 5512 observed reflections （I 〉 2σ（I））. Each MoV atom has a distorted octahedral coordination geometry,and the two coordination octahedra share a common edge to form a dioxo-bridged Mo2O4 unit which is coordinated by NTA ligands. The dianionic binuclear units [Mo2O4（HNTA）2]^2- are interconnected by Na^＋ into a layered structure.     

Synthesis and Crystal Structure of [2-Hydroxy- 5-（4-hydroxy-3-phenyliminomethylbenzyl）-benzylidene]-phenyl-amine

The title compound [2-hydroxy-5-（4-hydroxy-3-phenyliminomethyl-benzyl）-benzylidene]-phenyl-amine （C27H22N2O2, Mr = 406.47） was synthesized by 5,5′-methylene-bissalicylal- dehyde with aminobenezene, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group C2/c with a = 4.4026（6）, b = 1.501（13）, c = 0.95818（12） nm, β = 90.868（2）°, V= 4.2813（9） nm^3, Z= 8, Dc= 1.292 g/cm^3,μ = 0.010, F（000） = 1744, R = 0.0576 and wR = 0.1450 for 3766 observed reflections with I 〉 2σ（I）. X-ray analysis reveals that the molecule has a pair of intramolecular OH…N hydrogen bonds.     

Crystal Structure and Polymerization Activity of Bromo-（2-diphenylphosphino-N-（2-oxybenzylidene）-aniline）-nickel

The title compound,bromo-（2-diphenylphosphino-N-（2-oxybenzylidene）-aniline）- nickel,was synthesized by simple condensation of 2-diphenylphosphino-N-（2-oxybenzylidene）- aniline with NiBr2·6H2O and characterized by elemental analysis,IR spectra and single-crystal X-ray diffraction. The crystal belongs to the triclinic system,space group P1 with a = 9.756（2）,b = 10.232（2）,c = 13.313（3）A,α = 95.09（3）,β = 102.48（3）,γ = 95.45（3）o,V = 1283.5（4） A^3,C29H23BrNNiO2P,Mr = 587.07,Z = 2,Dc = 1.519 g/cm^3,λ（MoKα） = 0.71073 A,F（000） = 596 and μ = 2.402 mm^-1. The structure was refined to the final R = 0.0408 and wR = 0.0965 for 4507 observed reflections （I 〉 2σ（I））. Intermolecular π-π interactions （with distances of about 3.705 A） are pronounced in the crystal structure. Under methylaluminoxane （MAO） activation,the title compound was able to catalyze norbornene polymerization,exhibiting good polymerization activities.