Studies on the energy band structures and chemical bond properties of LaX(X=N, P, As, Sb) crystals

The energy band structures of LaX(X=N, P, As, Sb) crystals have been studied by using LMTO-ASA method. The calculated energy gaps of these crystals are 2. 30 eV for LaN, 2. 05 eV for LaP, 1. 66 eV for LaAs and 1. 34 eV for LaSb. The results are in good agreement with experimental data, At the same time, using these calculated results of energy band structures of these crystals, the chemical bond properties have been analyzed and calculated, The covalency values of these crystals are 26.15% for LaN, 32.54% for LaP, 33.30% for LaAs and 36.49% for LaSb, which agree satisfactorily with the calculated ones by using PV (Phillips-Vechten) theory.

LaX(X=N,P,As,Sb)晶体的能带结构和化学键性质研究

用ＬＭＴＯ－ＡＳＡ能带程序计算了ＬａＸ（Ｘ＝Ｎ，Ｐ，Ａｓ，Ｓｂ）晶体的能带结构，得到的晶体能隙分别为ＬａＮ２．３０ｅＶ，ＬａＰ２．０５ｅＶ，ＬａＡｓ１．６６ｅＶ，ＬａＳｂ１．３４ｅＶ，与实验结果基本相符．利用价电子总数在阴阳离子上的分配数之比，给出计算晶体化学键性质的经验关系式，根据该式计算晶体化学键的共价性与文献结果非常吻合，说明了该关系式的合理性

Complete assignment of H-1-NMR resonances of the king cobra neurotoxin CM-11

The king cobra(Ophiophagus hannah) neurotoxin CM-11 is long-chain peptide with 72 amino acid residues. Its complete assignment of H-1-NMR resonances was obtained using various 2D-NMR technologies, including DQF-COSY, clean-TOCSY and NOESY.

眼镜王蛇神经毒素CM-11核磁共振氢谱谱峰的完全归属

眼镜王蛇抽提物ＣＭ－１１为含７２个残基的长链神经毒素，对其进行了ＤＱＦ－ＣＯＳＹ，ＴＯＣＳＹ和ＮＯＥＳＹ等一系列２Ｄ－ＮＭＲ谱测定，借助序列专一归属法完成了ＣＭ－１１ＮＭＲ氢谱的完整归属。

A new method for the preparation of fullerol

Reaction of C-60 with excessive potassium in toluene at refluxing temperature results in black precipitate KaC60 with high conversion, which can completely be hydrolyzed to prepare the fullerol. Investigations including FT-IR. H-1 NMR C-13 NMR, UV-Vis and FABMS of the product were reported.

Li_8SiN_4-Li_3N-BN体系中立方BN转化行为的研究

研究了高温高压下x·Li_8SiN_4-0.1(1-x)·Li_3N-0.9(1-x)·BN体系中立方氮化硼(cBN)的转化行为。Li_8SiN_4的存在可显著改善cBN晶体的发育,提高晶体质量。在4.2～5.5GPa,1340～1750℃范围内确定了x=4.8％时体系的cBN转化区,并对转化区内cBN转化率、平均生长速度、成核速度及破碎强度与转化温度和压力的关系进行了研究。

A STUDY OF SURFACE OXYGEN SPECIES FROM LA-ME-O (ME=MG, CA, SR, BA) CATALYSTS FOR METHANE OXIDATIVE COUPLING

CO2-TPD was used to study the surface basicity of La-Me-O mixed oxides and O-2-TPD, CH4-TPD were employed to study the surface active oxygen species. Comparing the CO2-TPD with O-2-TPD, we can see that the basicity of catalyst is in parallel with the catalystic activity. The stronger basicity is more profitable for the catalyst to adsorb oxygen to form active oxygen species and to activate CH4 by breaking a C-H bond, By comparing the catalytic activity, the results showed that La-Ba-O(La/Ba=7/3) catalyst had the strongest basicity, and it gave the highest CH4 conversion and C-2 selectivity, The results from the pulse reaction showed that the lattice oxygen participated in the OCM reaction without gas oxygen, and it was the selective oxygen species.

Study of FT-Raman Spectroscopy on the Effects of Lanthanide Ions and Their Complexes on the Fluidity of Dipalmitoylphosphatidylethanolamine Bilayer

The effects of lanthanide ions and their complexes of citrate and DTPA ligands on the fluidity of dipalmitoylphosphatidylethanolamine (DPPE) bilayers have been studied by FT-Raman spectroscopy. the results show that lanthanide ions of lower concentrationn decrease the fluidity of acyl chains of DPPE bilayers and change the conformation of C C-C backbone from gauche to the trans lanthanide ions of higher concentration, however, increase the fluidity of acyl chains and increase the gauche population of C-C-C backbone. Lanthanide complex of citrate have no effect on the fluidity of acyl chains of DPPE bilayers in the region of experimental concentration, but La-DTPA complex increase slightly the fluidity of acyl chains. the results also indicated that lanthanide ion of lower concentration changed the lattice packing of hydrocarbon chains from hexagonal form to orthorhombic form, but it is still in hexagonal or distorted hexagonal lattice cell in the gel state in the presence of metal ions and lanthanide complexes of higher concentration

甲烷氧化偶联La－Me－O（Me＝Mg，Ca，Sr，Ba）系催化剂表面氧种的研究

利用ＣＯ_２－ＴＰＤ法考察了Ｌａ－Ｍｅ－Ｏ（Ｍｅ＝Ｍｇ，Ｃａ，Ｓｒ，Ｂａ）系催化剂的表面碱性，并用Ｏ_２－ＴＰＤ、ＣＨ_４－ＴＰＤ法对该体系的表面活性氧种进行了表征，并与催化性能相关联。结果表明，Ｌａ－Ｂａ－Ｏ催化剂由于表面强碱性中心数目多，产生活性氧种的数目也多，有利于甲烷的活化，因而具有最高的甲烷转化率和Ｃ_２烃选择性。脉冲反应表明，在无气相氧存在下，表面晶格氧参与了氧化偶联，而且是选择氧化的活性氧种。

含有机硅三元多嵌段共聚物的研究──Ⅲ．不同硬段、半硬段对含有机硅三元多嵌段共聚物性能的影响

以双酚Ａ聚砜或酚酞作为硬段，聚对羟基苯乙烯、酚醛、聚羟基醚或聚羟基醚砜作为半硬段，聚二甲基硅氧烷作为软段合成了七种三元多嵌段共聚物，并对其稳定性、动态力学性能进行了比较详细的研究。结果表明这类共聚物在溶液中的稳定性及热稳定性主要与半硬段有关；它们的形态结构同属于微相分离，并在很宽的温度范围内表现出优良的弹性体性质。三元多嵌段共聚物中硬段与半硬段的相容性直接影响其力学性能，当两者的相容性好时，其强度高于对应的二元多嵌段共聚物。

APPLICATION OF ULTRAMICROELECTRODES IN STUDIES OF HOMOGENEOUS CATALYTIC REACTIONS .3. THE CONDITION FOR QUASI-1ST AND 2ND-ORDER HOMOGENEOUS CATALYTIC REACTIONS AT ULTRAMICRODISK ELECTRODES IN THE STEADY-STATE

The conditions for quasi-first and second order homogeneous catalytic reactions and their variation with each other at an ultramicrodisk electrode in the steady state are discussed in this paper. The order of reaction can be controlled by changing the dimension of the ultramicroelectrode: the second order reaction can be changed to quasi-first by decreasing the dimension of the ultramicroelectrode. An example of this is given. The main factor effect on the reaction order is the dimension of the ultramicroelectrode. The K4Fe(CN)6-aminopyrine system is selected to confirm the theory, the experiments showing that the system is a second order reaction at a 432 mum microelectrode, and a quasi-first order reaction at a 19 mum ultramicroelectrode. The kinetic constant of the system can be determined by applying the previous theory of homogeneous catalytic reaction.

Sb-Fe催化剂的活性结构和在丙烯氨氧化中的催化作用机理研究

用XRD,Mossbauer,XPS和TPD研究了Sb-Fe催化剂的活性组分和它们的催化行为以及TPD的产物分布。XRD测定表明,活性组分可能有FeSbO_4和Sb_2O_4。穆斯堡尔谱结果确定活性组分除有FeSbO_4外,还有FeSb_2O_6。由富锑催化剂的XPS分析,出现结合能为709.3eV的肩峰,进一步证明含Fe_(2+)新活性组分FeSb_2O_6的存在。由Fe_(3+)和Fe_(2+)含量与活性的关系可以得出结论,催化作用取决于FeSbO_4,FeSb_2O_6和Sb_2O_4的协同作用,FeSb_2O_6是表面活性中心。最后,由催化剂的活性组分和催化作用以及TPD产物分布初步探讨了催化作用机理。

辉光放电中处理聚四氟乙烯表面——Ⅱ.ESR研究PTFE膜自由基

在外部电极电容耦合式反应装置中,对聚四氟乙烯(PTFE)膜进行了辉光放电处理。通过电子自旋共振(ESR)谱研究了PTFE在处理过程中所产生的自由基,着重讨论了温度对ESR谱的影响。最后,以DPPH为内标,测定了处理后PTFE膜的自由基浓度,并考察了自由基在空气中的衰减情况。

环辛二烯基稀土配合物的合成与表征

迄今,有关环辛二烯基作为配体的金属有机化合物报道得很少,只报道过它的碱金属、碱土金属及为数不多的过渡金属化合物,而从未报道过环辛二烯基稀土化合物。本文通过元素分析、红外光谱、核磁共振、质谱、热失重及气相色谱分析,确认合成了下述环辛二烯基稀

The complete mitochondrial genome of the large yellow croaker, Larimichthys crocea (Perciformes, Sciaenidae): Unusual features of its control region and the phylogenetic position of the Sciaenidae

To understand the systematic status of Larimichthys crocea in the Percoidei, we determined the complete mitochondrial (mt) genome sequence using 454 sequencing-by-synthesis technology. The complete mt genome is 16,466 bp in length including the typical structure of 22 tRNAs, 2 rRNAs, 13 protein-coding genes and the noncoding control region (CR). Further sequencing for the complete CR was performed using the primers Cyt b-F and 12S-R on six L crocea individuals and two L polyactis individuals. Interestingly, all seven CR sequences from L crocea were identical while the three sequences from L polyactis were distinct (including one from GenBank). Although the conserved blocks such as TAS and CSB-1, -2, and -3 are readily identifiable in the control regions of the two species, the typical central conserved blocks CSB-D, -E, and -F could not be detected, while they are found in Cynoscion acoupa of Sciaenidae and other Percoidei species. Phylogenetic analysis shows that L crocea is a relatively recently emerged species in Sciaenidae and this family is closely related to family Pomacanthidae within the Percoidei. L crocea, as the first species of Sciaenidae with complete mitochondrial genome available, will provide important information on the molecular evolution of the group. Moreover, the genus-specific pair of primers designed in this study for amplifying the complete mt control region will be very useful in studies on the population genetics and conservation biology of Larimichthys. (c) 2008 Elsevier B.V. All rights reserved.