Defect Cluster-Induced X-Ray Diffuse Scattering in GaN Films Grown by MOCVD

High-resolution X-ray diffraction has been employed to investigate the diffuse scattering in a (0001) oriented GaN epitaxial film grown on sapphire substrate. The analysis reveals that defect clusters are present in GaN films and their concentration increases as the density of threading dislocations increases. Meanwhile, the mean radius of these defect clusters shows a reverse tendency. This result is explained by the effect of clusters preferentially forming around dislocations, which act as effective sinks for the segregation of point defects. The electric mobility is found to decrease as the cluster concentration increases.

6-(1H-吲哚-3-甲基)-5-乙基-3H-嘧啶-4-酮类化合物的合成及抗HIV活性研究

基于二氢烷氧苄基嘧啶酮(DABO)类非核苷类逆转录酶抑制剂(NNRTIs)的构效关系研究,设计合成了2个新的6-(1H-吲哚-3-甲基)-5-乙基-3H-嘧啶-4-酮类化合物,并采用C8166细胞进行了体外抗HIV活性测试,为新型S-DABO类非核苷类逆转录酶抑制剂结构修饰提出了新的设想.

SYNTHESES OF METHYLCYCLOPENTADIENYL DERIVATIVES OF LANTHANIDES (LN = LA-ND) AND CRYSTAL-STRUCTURES OF [(THF)2LI(MU-CL)2]2[MECPND(THF)] AND [LI(DME)3][MECPLA(NPH2)3]

The reaction of LnCl3.2LiCl with 1 equiv of MeCpNa in THF gives the complexes [(THF)2Li(mu-Cl)2]2[MeCpLn(THF)] (Ln = Nd (1), La (2)) in good yield. These precursors react further with 2 equiv of LiNPh2 to produce the new complexes [Li(DME)3][MeCpLn(NPh2)3] (Ln = La (3), Pr (4), Nd (5)). They have been characterized by elemental analyses and IR and NMR spectra, as well as by structural analyses of 1 and 3. The chloride 1 crystallizes in the monoclinic space group P2(1)/n (No. 14) with a = 12.130 (5) angstrom, b = 17.343 (5) angstrom, c = 17.016 (5) angstrom, beta = 108.54 (3)-degrees, V = 3393.87 angstrom3, Z = 4, and D(c) = 1.45 g/cm3. Least-squares refinement led to a final R value of 0.051 (I greater-than-or-equal-to 3-sigma(I(o))) for 2004 independent reflections. Complex 3 crystallizes in the monoclinic space group P2(1)/c (No. 14) with a = 18.335 (6) angstrom, b = 16.576 (5) angstrom, c = 17.461 (6) angstrom, beta = 96.04 (3)-degrees, V = 5277.17 angstrom3, D(c) = 1.26 g/cm3, Z = 4, and R = 0.057 (I greater-than-or-equal-to 2.5-sigma(I(o))) for 3378 reflections. The structure of 3 consists of discrete ion pairs [Li(DME)3]+ and [MeCpLa(NPh2)3]- with average La-N and La-C(ring) distances of 2.459 (8) and 2.84 (1) angstrom, respectively.

3~C-NMR 研究糠醇和糠醇与三■2—羟乙基■异氰尿酸酯缩聚磺化反应

80年代初,Kurihara 等开发的 PEC—1000复合膜,首次实现了工业规模的海水一级淡化,并在无机和有机水溶液的分离和浓缩方面显示了巨大潜力。据分析这种高效分离膜的功能分离层的主要结构成分是糠醇(FA)和三(?)2一羟乙基(?)异氰尿酸酯(THEIC)