C_1桥联的茂金属化合物(Cp)CR_1R_2(Flu)MCl_2的合成及其催化烯烃聚合活性

合成了 6种单碳桥联的含芴 (Flu)茂 (Cp)基 B族茂金属催化剂 ,研究了它们催化烯烃聚合的能力 .通过 IR,1H NMR,EI-MS和元素分析对化合物进行了表征 .用所合成的茂金属化合物与 MAO所组成的催化体系对乙烯、丙烯的聚合进行了研究 .其中金属为 Ti的催化剂没有聚合活性或活性极低 .金属为 Zr的催化剂有一定的催化活性 ,用不同的催化剂得到的聚合物性质有一定的差异

Hierarchal structure of the simplified Navier-Stokes equations (SNSE) and its mechanical connotation and application

The hierarchial structure and mathematical property of the simplified Navier-Stokesequations (SNSE) are studied for viscous flow over a sphere and a jet of compressible flu-id. All kinds of the hierarchial SNSE can be divided into three types according to theirmathematical property and also into five groups according to their physical content. Amultilayers structure model for viscous shear flow with a main stream direction is pre-sented. For the example of viscous incompressible flow over a flat plate there existthree layers for both the separated flow and the attached flow; the character of thetransition from the three layers of attached flow to those of separated flow is elucidated.A concept of transition layer being situated between the viscous layer and inviscidlayer is introduced. The transition layer features the interaction between viscous flow andinviscid flow. The inner-outer-layers-matched SNSE proposed by the present author inthe past is developed into the layers matched (LsM)-SNSE.

一种新型芴类衍生物的光谱性质研究

合成了具有大π共轭性的对称型芴类衍生物9，9-二（2-乙基已基）-2，7-（2-（4-甲氧基）苯-2，1-乙烯基）芴（简写为MO-F1u—MO）。通过元素分析、质谱、紫外-可见光谱和红外光谱对其进行了表征。测试了该染料在乙腈、二氯甲烷、四氢呋喃和正己烷4种不同极性溶剂中的线性吸收光谱和单光子荧光谱。结果发现溶剂效应对吸收光谱和荧光光谱表现出不同程度的影响，对产生这些光谱行为的主要原因进行了讨论。

不同水生植物对滇池入湖河道污水净化效能的比较

有关水生植物净化污水的研究已有广泛报道,但现有成果多来源于静态的室内研究,所用植物多为生活型接近的物种。为了比较不同生活型植物对河道污水的原位净化效果差异,构建了由水芹菜(Oenanthe javanica)、马尾草(Equisetum flu-viatile)、伊乐藻(Elodea Canadensis Michx.)和狐尾藻(Myriophyllum verticillatum L.)等4种不同生活型水生植物组成的水生植物塘系统,研究塘中不同植物对滇池入湖河道污水中氮、磷等指标去除效能的差异。结果表明

Raman scattering of folded acoustic phonons in self-assembled Si/Ge dot superlattices

Self-assembled Si/Ge dot multilayers with small, uncorrelated dots fabricated by molecular beam epitaxy in the Stranski-Krastanov growth mode are studied by Raman scattering of folded longitudinal acoustic (FLA) modes. The FLA Raman spectra are analyzed and modeled with respect to mode frequencies and the spectral envelope of mode intensities. The deduced average superlattice properties are consistent with results from atomic force microscopy. The simple Rytov model used for Si/Ge layer structures reproduces very well the frequencies of the FLA modes up to 150 cm(-1). The nonlinearity of phonon dispersion curves in bulk Si for large momenta, however, becomes important for modeling the higher frequencies of observed FLA modes up to 22nd order. The effective dot layer width and an activation energy for thermal intermixing of 2.1+/-0.2 eV are determined from the spectral envelopes of FLA mode intensities of as-grown and annealed Si/Ge dot multilayers. (C) 2004 American Institute of Physics.

单组分茂稀土催化剂催化极性单体聚合

本论文分为两部分，第一部分合成一些新型茂稀土催化剂。一共合成出四类22种稀土金属有机配合物。第二部分尝试了茂基稀土配合物对甲基丙烯酸甲酯（MMA）、丙烯腈（AN）、4-乙烯基吡啶（4-VP）、已内酯（CL）的聚合，研究了其聚合规律，并对其聚合物进行了表征。主要结果如下：1. 合成出四类22种稀土金属有机配合物：第一类：氯化稀土配合物(C_9H_7)_2LnCl(THF)_n (Ln = Y，Yb，Nd，Sm)，Me_2Si(Ind)_2 YCl(THF)_n，Me_2Si(Flu)_2YCl(THF)_n， Me_2Si(Ind)(Flu)YCl(THF)_n。第二类：稀土胺化物(C_9H_7)_2LnN(i-Pr)_2(THF) (Ln = Y，Yb)， Me_2Si(Ind)_2YN(i-Pr)_2，Me_2Si(Flu)_2Y N(i-Pr)_2， Me_2Si(Ind)(Flu)YN(i-Pr)_2。第三类：稀土与铝双金属配合物(C_9H_7)_2Y(μ-Et)_2AlEt_2，Me_2Si(Flu)_2Y(μ-Et)_2AlEt_2， Me_2Si(Ind)(Flu)Y(μ-Et)_2AlEt_2，(C_9H_7)_2Sm(μ-Me)_2AlMe_2， (C_9H_7)_2Sm(μ-Et)_2AlEt_2。第四类：二价钐配合物(C_9H_7)_2Sm(THF)_3，(C_(13)H_9)_2Sm(THF)_2， Me_2Si(Flu)_2Sm(THF)_x，Me_2Si(Ind)(Flu)Sm (THF)_x， (CH_2)_2(fLU)_2Sm(THF)_x。对每类配合物分别进行了核磁、红外及紫外分析。2.茂稀土配合物催化极性单体聚合（1）甲基丙烯酸甲酯（MMA）聚合 首次发现(C_9H_7)_2Y(μ-Et)_2AlEt_2， (C_9H_7)_2LnN(i-Pr)_2(THF) (Ln = Y，Yb)， Me_2Si(Ind)_2YN(i-Pr)_2，Me_2Si(Flu)_2YN(i-Pr)_2， Me_2Si(Ind)(Flu)YN(i-Pr)_2 MMA聚合均表现出极高的催化活性，其中以(C_9H_7)_2Y(μ-Et)_2AlEt_2催化MMA所得的PMMA全同含量（mm）可达94.8%。（2）丙烯腈（AN）聚合：首次发现(C_9H_7)_2Y(μ-Et)_2AlEt_2，(C_9H_7)_2LnN(i-Pr)_2(THF) (Ln=Y，Yb)对AN聚合表现出较高的催化活性，并且发现往此催化体系中加入添加剂PhONa，基催化活性及分子量都明显提高。其聚合物的立构规整性用~(13)C-NMR谱进行了表征，发现聚合物的结构均为无规结构。(3)4-乙烯基吡啶（4-VP）聚合：首次发现(C_9H_7)_2Y(μ-Et)_2AlEt_2，(C_9H_7)_2Sm(THF)_3对4-VP聚合表现出很好的催化活性，并且发现单体浓度及催化剂用量对4-VP聚合有较大的影响。此外，一些桥联配体的二价钐配合物Me_2Si(Flu)_2Sm(THF)_x，Me_2Si(Ind)(Flu)Sm(THF)_x， (CH_2)_2(Flu)_2Sm(THF)_x也能催化4-VP聚合，但其催化活性较低。（4）已内酯（CL）聚合：比较了各类茂稀土催化剂对己内酯开环聚合的催化活性。发现Ind_2Y(μ-Et)_2AlEt_2，Ind_2YN(i-Pr)_2(THF)， Me_2Si(Ind)(Flu)YN(i-Pr)_2(THF)，Me_2Si(Flu)_2YN(i-Pr)_2(THF)， Me_2Si(Ind)_2YN(i-Pr)_2(THF)，Ind_2Sm(THF)_x， Me_2Si(Flu)_2Sm(THF)_x，Me_2Si(Ind)(Flu)Sm(THF)_x， (CH_2)_2(Flu)_2Sm(THF)_x均能有效地催化己内酯开环聚合，二价稀土金属配合物的催化活性要比三价稀土金属配合物高。

Highly 3,4-selective living polymerization of isoprene with rare earth metal fluorenyl N-heterocyclic carbene precursors

Fluorenyl modified N-heterocyclic carbene ligated rare earth metal bis(alkyl) complexes, (Flu-NHC)Ln(CH2SiMe3)2 (Flu-NHC = (C13H8CH2CH2(NCHCCHN)C6H2Me3-2,4,6); Ln = Sc (1a); Ln = Y (1b); Ln = Ho (1c); Ln = Lit (1d)), were synthesized and fully characterized by NMR and X-ray diffraction analyses. Complexes Ib-d with the activation of (AlBu3)-Bu-i and [Ph3C][B(C6F5)4] exhibited high activity, medium syndio-but remarkably high 3,4-regio-selectivity, and the unprecedented livingness for the polymerization of isoprene. Such distinguished catalytic performances could be maintained under various monomer-to-initiator ratios (500-5000) and broad polymerization temperatures (25-80 degrees C).

Copolymerization of ethylene with norbornene catalyzed by cationic rare earth metal fluorenyl functionalized N-heterocyclic carbene complexes

Rare earth metal bis(alkyl) complexes attached by fluorenyl modified N-heterocyclic carbene (NHC) (Flu-NHC)Ln(CH2SiMe3)(2) (Flu-NHC = (C13H8CH2CH2(NCHCCHN)C6H2Me3-2,4,6); Ln = Sc (2a); Y (2b); Ho (2c); Lu (2d)), ((tBu)Flu-NHC)Ln(CH2SiMe3)(2) ((tBu)Flu-NHC = 2,7-(Bu2C13H6CH2CH2)-Bu-t(NCHCCHN)C6H2Me3-2,4,6; Ln = Sc (1a); Lu (1d)) and attached by indenyl modified N-heterocyclic carbene (Ind-NHC)Ln(CH2SiMe3)(2) (Ind-NHC = C9H6CH2CH2(NCHCCHN)C6H2Me3-2,4,6; Ln = Sc (3a); Lu (3d)), under the activation of (AlBu3)-Bu-i and [Ph3C][B(C6F5)(4)], showed varied catalytic activities toward homo- and copolymerization of ethylene and norbornene. Among which the scandium complexes, in spite of ligand type, exhibited medium to high catalytic activity for ethylene polymerization (10(5) g mol(Sc)(-1) h(-1) atm(-1)), but all were almost inert to norbornene polymerization. Remarkably, higher activity was found for the copolymerization of ethylene and norbornene when using Sc based catalytic systems, which reached up to 5 x 10(6) g mol(Sc)(-1) h(-1) atm(-1) with 2a. The composition of the isolated copolymer was varying from random to alternating according to the feed ratio of the two monomers (r(E) = 4.1, r(NB) = 0.013).

Preliminary investigations on polymerization catalysts composed of lanthanocene and methylaluminoxane

The polymerization of butadiene(Bd), isoprene(Ip) and styrene(St) has been examined using the six catalyst systems composed of lanthanocene, (C5H9Cp)(2)NdCl(I), (C5H9Cp)(2)SmCl(II), (MeCp)(2)SmOAr'(III), (Ind)(2)NdCl(IV), Me2Si(Ind)(2)NdCl(V) and (Flu)(2)NdCl(VI), and methylaluminoxane(MAO) respectively. All of them can be used to form the polyisoprene with molecular weights of 1 to 10 thousand and cis-1,4-unit contents of 41 to 47%. (I), (II) and (III) of them can be also used to form the polybutadiene with molecular weights of 10 to 20 thousand and cis-1,4-unit contents of 62 to 78%. In addition, the catalysts from (II) to (V) are still active for St polymerization and (II) of them gives a syndio -rich random polystyrene. It is noteworthy that (II) and (III) are active for homopolymerization of Bd, Ip and St in the same polymerization condition.

HIGHLY SENSITIVE AND SELECTIVE DETERMINATION OF RIBOFLAVIN BY FLOW-INJECTION ANALYSIS USING PARALLEL DUAL-CYLINDER MICROELECTRODES

A novel wall-jet cell with parallel dual cylinder (PDC) microelectrodes was constructed and used for flow injection analysis (FLA). The detector takes the advantages of ''redox recycling'' between bipotentiostated microcylinder electrodes (- 0.4 V/SCE an

重稀土离子电极的研制及其应用

稀土分离流程中,需要能随时测定稀土含量而又简便的分析方法,离子选择电极可能适应这种需要。我们在稀土电极研究的基础上,研制了重稀土离子选择电极,并以该电极膜制成重稀土流通池,将其应用在流动注射分析中,可能是重稀土分析中较理想的方法之一。1 主要仪器和试剂 主要仪器有PW 9409酸度计(Philips),FlA-T_2通用流动注射仪(东北电力学院仪器仪

H5N1 avian influenza re-emergence of Lake Communication Qinghai: phylogenetic and antigenic analyses of the newly isolated viruses and roles of migratory birds in virus circulation

Highly pathogenic avian influenza H5N1 virus has swept west across the globe and caused serious debates on the roles of migratory birds in virus circulation since the first large-scale outbreak in migratory birds of Lake Qinghai, 2005. In May 2006, another outbreak struck Lake Qinghai and six novel strains were isolated. To elucidate these QH06 viruses, the six isolates were subjected to whole-genome sequencing. Phylogenetic analyses show that QH06 viruses are derived from the lineages of Lake Qinghai, 2005. Five of the six novel isolates are adjacent to the strain A/Cygnus olor/Croatia/1/05, and the last one is related to the strain A/duck/Novosibirsk/ 02/05, an isolate of the flyway. Antigenic analyses suggest that QH06 and QH05 viruses are similar to each other. These findings implicate that QH06 viruses of Lake Qinghai may travel back via migratory birds, though not ruling out the possibility of local circulation of viruses of Lake Qinghai.