LaMSb_2O_7:R~(3+)(M=Li,Na,K;R=Eu,Dy,Bi)的合成、组成、结构及发光性能

研究了激活离子Eu~(3+),Dy~(3+)和Bi~(3+)在具有相同结构的LaMSb_2O_7(M=Li,Na,K)中的发光特性,得到了发白光的磷光体LaNaSb_2O_7:Dy~(3+)。讨论了化学键的共价程度对Eu~(3+)和Dy~(3+)超灵敏跃迁强度比的影响。发现当用281nm激发试样时,Bi~(3+)对Eu~(3+)具有敏化作用并解释了其原因。

端羟基丁二烯～丙烯腈共低聚反应中共聚物组成的控制

本工作结合水轮机涂层材料的研制，针对端羟基丁二烯～丙烯腈的共低聚反应，研究了共聚物组成的控制。根据自由基共聚反应理论，提出了一个控制共聚物组成的新计算方法。并根据这种计算方法，合成了具有均匀组成的丁腈羟液体聚合物。用Skeist公式的积分形式~((54))，对所研究的体系，进行了计算。计算结果表明：不补加单体时，丁二烯～两烯腈的共聚反应过程中，单体组成及共聚物组成的变化是显著的。为了合成组成比较均匀的共聚物，必须在反应过程中，补加消耗较快的单体——丙烯腈。根据共聚方程式和反应体系及共聚物中单体浓度的相互关系，推导出丙烯腈的补加量C_A的表示公式为：C_A = (B)_o(R-F)(1-(B)/((B)_o))式中，(B)_o是单体B的起始浓度，R为聚物中单体浓度比，F为单体浓度比。又根据共聚反应速度方程式~((31))及引发剂热分解速度公式，推导出(B)/((B)_o)与反应时间t的函数关系式为：(B)/((B)_o) = exp[K(f(I)_o/k_d)~(1/2)(l~(-k_dt/2)-1)]式中(I)_o为引发剂起始浓度，(B)为反应过程中单体B的浓度，k_d为引发剂分解速度常数，f为引发效率，K为常数。最后得到C_A的表示式为：C_A = (B)_o(R-F){1-exp[K(f(I)_o/k_d)~(1/2)(e~(k_dt/2)-1)]}按上式计算出的C_A的量，在反应过程中补加丙烯腈，这样合成的丁腈羟，实验证明，其组成是均匀的。根据Goldfinger公式~((35))，由测得的竞聚率和单体克分子比，计算了丁腈羟的序列分布。计算的结果说明：所合成的丁腈羟不仅组成是比较均匀的，其序列分布也是比较均匀的。这有利于提高丁腈羟作为水轮机涂层材料的耐磨、耐汽蚀及粘结性能。

~(126)I高自旋态的识别

利用重离子融合蒸发反应12 2 Sn(11B ,5n2p)布居了双奇核12 6 I的激发态 ,首次建立了具有集体带结构特征的能级纲图 ,其中包括 2 0条新γ跃迁 .所建能级纲图的核素归属指定得到了核反应12 4 Sn(7Li,5n)的交叉支持 .简单讨论了所建带结构的可能组态 .

森林叶凋落物混合分解的研究I.缩微(Microcosm)实验

采用缩微实验法 ,初步系统研究了杉木叶凋落物分别与火力楠、红栲和木荷 3个阔叶树种之一的叶凋落物两两混合分解的动态变化 ,以探明凋落物混合分解过程中可能存在的相互作用 .结果表明 ,杉木叶凋落物与 3种阔叶树种叶凋落物两两混合分解时所表现出不同的相互作用形式 :杉木与木荷表现出抑制作用 ,杉木与红栲或火力楠表现为较弱的促进作用 .

Electrical conductivity of a single Au/polyaniline microfiber

We report the measurements of conductivity, I-V curve, and magnetoresistance of a single Au/polyaniline microfiber with a core-shell structure, on which a pair of platinum microleads was attached by focused ion beam. The Au/polyaniline microfiber shows a much higher conductivity (similar to 110 S/cm at 300 K) and a much weaker temperature dependence of resistance [R(4 K)/R(300 K)=5.1] as compared with those of a single polyaniline microtube [sigma(RT)=30-40 S/cm and R(4 K)/R(300 K)=16.2]. The power-law dependence of R(T)proportional to T-beta, with beta=0.38, indicates that the measured Au/polyaniline microfiber is lying in the critical regime of the metal-insulator transition. In addition, the microfiber shows a H-2 dependent positive magnetoresistance at 2, 4, and 6 K.

Kinetic analysis of TNF immune complex by using surface plasmon resonane

The kinetic analysis of the interaction between tumor necrosis factor(TNF) and its monoclonal antibody was performed by surface plasmon resonance(SPR) technique. The monoclonal antibody was immobilized to the surface of CM5 sensor chip by amine coupling. TNF at different concentrations was injected across the mAb immobilized surface. The interaction was recorded in real time and could be seen on the sensorgram. One cycle, including association, dissociation and regeneration, lasted no more than 15 min. The interaction results was evaluated using 1 : 1 Langmuir binding model. The kinetic rate constants were calculated to be: k =1.68 X 10(3) L (.) mol(-1) (.) s(-1), k(d) = 1.73 X 10(-4) s(-1), and the affinity constants K-A = 9. 7 X 10(3) L (.) mol(-1), K-r)= 1. 03 X 10(-7) Mol (.) L-1. The X-2 was 3.47, which showed that the interaction is consistent with the 1 : I model. We can see from the results that although there are two binding sites in one mAb molecule, TNF reacts with each site in an independent and noncooperative manner.

Synthesis of lanthanide-alkylaluminium bimetallic complexes and studies on their catalytic activities for polymerization of some polar monomers

Three new lanthanide (Ln)-alkylaluminium (Al) bimetallic complexes with the formula [(mu-CF3CO2)(2)Ln(mu-CF3CHO2)AIR(2) . 2THF](2) (Ln = Nd, Y, R=i-C4H9 (i-Bu); Ln=Eu, R=C2H5(Et); THF=tetrahydrofuran) were synthesized by the reaction of Ln(CF,CO,), (Ln=Nd, Y) with HAI (i-Bu)(2) and of Eu(CF3CO2)(3) with AlEt(3), respectively. Their crystal structures were determined by X-ray diffraction at 233 K. [(mu-CF3CO2)(2)Nd (mu-CF3CHO2)Al(i-Bu)(2) . 2THF](2) (Nd-Al) and [(mu-CF3CO2)(2)Y(mu-CF3CHO2)Al(i-Bu)(2) . 2THF](2) (Y-Al) are isomorphous and crystallize in space group with a=12.441(3) Angstrom [12.347(5) Angstrom for Y-Al], b=12.832(3) Angstrom [12.832(4) Angstrom], c=11.334(3) Angstrom [11.292(8) Angstrom], alpha=104.93 (2)degrees [104.45(4)degrees], beta=98.47(2)degrees [98.81(4)degrees], gamma=64.60(2)degrees [64.30(3)degrees], R=0.519 [0.113], R(w)=0.0532 [0.110], Z=1 and [(mu-CF3CO2)(2)Eu(CF3CHO2)AlEt(2) . 2THF](2)(Eu-Al) in space group P2(1)/n with a=11.913(6) Angstrom, b=14.051(9) Angstrom, c=17.920(9) Angstrom, alpha=101.88(11)degrees, beta=gamma=90 degrees, R=0.0509, R(w)=0.0471 and Z=2. The six CF3CO2- (including CF3CHO2-) of each complex, among which pairs are equivalent, coordinated to Ln and Al in three patterns: (A) the two oxygen atoms in one of the three CF3CO2- type coordinated to two different Ln; (B) the two oxygen atoms in the second of CF3CO2- type coordinated to Ln and Al, respectively; (C) one of the two oxygen atoms in the third CF3CO2- type bidentately coordinated to two Ln and another oxygen coordinated to Al and one of the two Ln, respectively. Unlike types A and B, in type C the carboxyl carbon with a hydrogen atom bonded to it was found to appear as an sp(3)-hybridized configuration rather than an sp(2)-one. 1D and 2D NMR results further confirmed the existence of such a disproportionated CF3CHO2- ligand. Methyl methacrylate (MMA) and epichlorohydrin (ECH) could be polymerized by Y-Al or Eu-Al as a single-component catalyst and highly syndiotactic poly(MMA) was obtained. THF could also be polymerized by Y-Al in the presence of a small amount of ECH.

STRUCTURE OF AN ERBIUM COORDINATION COMPOUND WITH L-PROLINE, ([ER(PRO)2(H2O)5]CL3)(N)

catena-Poly[{pentaaqua(L-proline-O)-erbium-mu-(L-proline-O:O')} trichloride], {[Er(C5H9-NO2)2(H2O)5]Cl3}n, M(r) = 594.0, monoclinic, P2(1), a = 8.294 (1), b = 10.981 (3), c = 11.934 (3) angstrom, beta = 107.04 (2)degrees, V = 1039.2 (4) angstrom3, Z = 2, D(x) = 1.90 g cm-3, lambda(Mo Kalpha) = 0.71069 angstrom, mu = 45.2 cm-1, F(000) = 586, T = 298 K, R = 0.0244 for 1711 unique reflections [I > 3 sigma(I(o))]. The crystal consists of one-dimensional chains of infinite length in which one L-proline ligand bridges two neighboring Er ions, the other L-proline ligand being monodentate.

STRUCTURE OF HEXAMETHYLENETETRATELLURAFULVALENE DIIODIDE

C12H12I2Te4, M(r) = 920.44, monoclinic, P2(1)/n, a = 10.942 (2), b = 14.924 (2), c = 11.415 (2) angstrom, beta = 104.32 (1)-degrees, V = 1806.0 (5) angstrom 3, Z = 4, D(x) = 3.38 g cm-3, lambda(Mo K-alpha) = 0.71069 angstrom, mu = 100.7 cm-1, F(000) = 1592, T = 294 K, R = 0.033 for 1828 observed reflections. One of the Te atoms is bonded to the two I atoms, which are on either side of the molecular plane. The Te-I distances are 2.963 (1) and 2.961 (1) angstrom, which means oxidation at the Te atom instead of at the C = C bonds.