The bond ionicity in RBa2Cu3O7 (R=Pr, Sm, Eu, Gd, Dy, Y, Ho, Er, Tm)

RBa2Cu3O7 (R = Pr, Sm, Eu, Gd, Dy, Y, Ho, Er, Tm) has been studied using complex chemical bond theory. The results indicated that with the decreasing of R radius, the ionicities for all considered types of bond decrease. This is in good agreement with the experimental fact that T-c decreases with the decreasing of R radius. PrBa2Cu3O7 with no Ba-site Pr in this calculation is also predicted to be a superconductor. This supports the conclusion obtained by Blackstead et al. The ionicity for each bond obeys the following order: Ba-O > R-O > Cu(2)-O(1) > Cu(2)-O(2,3) > Cu(1)-O(4) similar to Cu(1)-O(1).

有机-无机自由基盐(DBTTF)_6PMo_(12)O_(40)·2H_2O的合成、性质和晶体结构

用电解法制备了有机－无机自由基盐（ＤＢＴＴＦ）６ＰＭｏ１２Ｏ４０·２Ｈ２Ｏ．用红外光谱、电子光谱和电子自旋共振谱进行了表征，测定了其磁化率、导电性和单晶的晶体结构．该晶体属三斜晶系，Ｐ１空间群．晶胞参数为ａ＝１．３７８７（７）ｎｍ，ｂ＝１．４２０４（２）ｎｍ，ｃ＝１．５７０２（２）ｎｍ，α＝１０４．５７０（８）°，β＝１０３．４１（２）°，γ＝９５．８０（２）°，Ｖ＝２．８５３（２）ｎｍ３，Ｚ＝１，Ｄｃ＝２．１４２Ｍｇ·ｍ－３，Ｒ＝０．０７２７．

LiMgAlF_6 : Tm~(3+) 的合成与光谱特性

采用高温固相反应法，ＬｉＦ／ＭｇＦ２／ＡｌＦ３＝１２０／１１０／１００，烧结温度为１００８Ｋ，烧结时间为４ｈ，在流动的高纯Ａｒ中合成了ＬｉＭｇＡｌＦ６：Ｔｍ３＋。对其结构和发光特性进行了研究。

Studies on extracting solutions of endohedral rare-earth metallofullerenes by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

Thirteen extracting solutions of rare-earth metallofullerenes containing La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb respectively have been investigated by means of matrix-assisted laser desorption/ionization time-of-night, mass spectrometry. The influences of the positive-ion/negative-ion mode, laser intensity, matrix and mass discrimination to the analytical results are studied, based on which the optimal analytical conditions have been determined. The results show that the extracting solutions contain large quantities of rare-earth metallofullerenes brs;des empty fullerenes, On the basis of comparing their relative intensities, the different structure stabilities and solubilities of metallofullerenes with different rare-earth metals encapsulated into the fullerene cages, as well as some possible reasons to those differences, are discussed.

ELECTROCHEMICAL-BEHAVIOR OF BIS(2 /17-ARSENOTUNGSTATE) LANTHANATES AND THEIR ELECTROCATALYTIC REDUCTION FOR NITRITE

A series of new catalysts, K-14[Ln(As2W17O61)(2)]. xH(2)O (Ln = La, Pr, Sm, Eu, Gd, Tb, Dy, Tm and Yb) which can electrocatalyze reduction of nitrite are presented and their electrochemical behavior is described in this paper. Bis(2:17-arsenotungstate) lanthanates which are monovacant Dawson derivatives, exhibit two 2-electron and one 1-electron waves, attributed to electron addition and removal from the tungsten-oxide framework that comprises each anion structure. The formal potentials of redox couples are dependent on solution pH. Double-hump principle of formal potentials takes effect with increasing atomic number of lanthanide elements following their special electronic shell structure. The third waves of all the heteropolyanions have good electrocatalytic activities for nitrite reduction at pH 5.0.

杂多酸的固载化Ⅲ．溶剂对H_4SiW_（12）O_（40）·24H_2O在活性

研究了Ｈ＿４ＳｉＷ＿（１２）Ｏ＿（４０）·２４Ｈ＿２Ｏ（ＳｉＷ＿（１２））在水、乙醇、乙酸、乙酸丁酯中在活性炭上的吸附得出，活性炭微孔结构对ＳｉＷ＿（１２）在其表面的吸附起着分子筛作用。水溶剂化的ＳｉＷ＿（１２）分子可顺利进入活性炭１．７ｎｍ左右的微孔，而其它溶剂化的ＳｉＷ＿（１２）分子，则需较大的孔径。提出了ＳｉＷ＿（１２）在活性炭表面吸附的微孔中孔扩散模型。

STUDIES ON ORGANOLANTHANIDE COMPLEXES .40. SYNTHESIS AND X-RAY STRUCTURE OF BIS (2-METHOXYETHYLCYCLOPENTADIENYL) YTTRIUM AND YTTERBIUM TETRAHYDROBORATES

New bis (2-methoxyethylcyclopentadienyl) yttrium and ytterbium tetrahydroborates (Ln = Y, 1; Yb, 2) have been synthesized in good yield by the reaction of bis (2-methoxyethylcyclopentadienyl) lanthanide chlorides (Ln = Y, Yb) with sodium borohydride in THF at room temperature. The title complexes were characterized by elemental analyses, MS, H-1 NMR and IR spectra. The crystal structures of 1 and 2 have been determined by X-ray diffraction. 1 crystallizes from THF-n-Hexane in space group Pna2(1) with unit cell parametert: a = 1.2390(3), b = 1.1339(2), c = 1.1919 (2) nm and V = 1.6745(6) nm3 with z = 4 for D(c) = 1.39 g.cm-3.The structure was solved by direct method and refined to final R = 0.061 (for 1730 observed reflections). The Space group of 2 is Pna2(1) with unit cell parameters: a = 1.2399(6), b = 1.1371(5), c = 1.1897(2) nm and V = 1.6773(1) nm3 with z = 4 for D(c) = 1.72 g.cm-3, R = 0.038 (for 2157 observed reflections). The X ray structures and IR reveal the bidentate yttrium and ytterbium tetrahydroborate complexes with the intramolecular coordination bonds between lanthanide metal and ligand oxygen atoms.

杂多化合物催化性能的研究 在相转移条件下Na_2HPW_(12)O_(40)在苯乙烯氧化反应中的催化作用

杂多化合物既有配合物和金属氧化物的结构特征,又有强酸性和氧化还原性。它是具有氧化还原和酸催化功能的双功能催化剂。另外,它还具有结构确定、再生速度快、活性高、不腐蚀设备和污染少等优点,被认为是继分子筛之后,最有研究价值和开发前景的催化剂之一。

固熔体60%NaAlSi_2O_6-40%CaMgSi_2O_6在高温高压下的相图的研究

在1.0～5.0GPa、700～1750℃条件范围内,对固熔体0.6NaAlSi_2O_6-0.4CaMgSi_2O_6进行了研究,探讨了该固熔体在高温高压下的存在行为,研究了由非晶态玻璃向翡翠转化过程中γT作用的相图,得到的透辉石翡翠的晶胞参数为α=0.9439nm,b=0.8573nm,c=0.5233nm,β=107.28°和V=0.41702nm~3。本实验中合成的宝石级翡翠为色泽温润,具有玻璃光泽,半透明的极富观赏性的透辉石翡翠。

杂多酸盐K_4H(SiMo_(11)VO_(40))·14H_2O的合成及晶体结构

杂多酸是种类多,应用广的重要的无机化合物。其中有一类是12-系列化合物Z,(XM_(12-n)M_n′O_(40))·mH_2O,中心离子X可以是过渡元素或非过渡元素;M常是Mo、W;M′为V_(5+)、Mn_(2+)、CO_(2+)等;n=0,1,2…;Z为H~+或一价阳离子;y=1,2,…。它们同其相应氧化型化合物比较具有引人注目的特性,但迄今尚未见到还原型化合物晶体结构文章,只是

杂多酸盐K_4H[SiMO_(11)VO_(40)]·18H_2O 1和K_4H_2[PMo_9V_3O_(40)]·18H_2O 2的晶体结构

杂多酸是种类多,应用广的重要的无机化合物。其中有一类是12-系列化合物Z,(XM_(12-n)M_n′O_(40))·mH_2O,中心离子X可以是过渡元素或非过渡元素;M常是Mo、W;M′为V_(5+)、Mn_(2+)、CO_(2+)等;n=0,1,2…;Z为H~+或一价阳离子;y=1,2,…。它们同其相应氧化型化合物比较具有引人注目的特性,但迄今尚未见到还原型化合物晶体结构文章,只是

K_4H_2[PMo_9V_3O_(40)]·10H_2O的合成及其晶体结构

采用低温技术,用 X 射线单晶衍射法测定了标题化合物的结构.晶体属 P4/mnc 空间群,a=12.515(3),c=17.636(7),Z=2.用788个独立可观测反射精修所有结构参数得 R=0.061.钼钒磷杂多酸阴离子中,PO_4四面体是无序的,P—O 键长1.54.M(Mo,V)是6配位,M—O 键长1.62—2.48.K 是7配位,K—O 键长2.84—3.10.

YP_5O_(14):Er~(3+),Tm~(3+)晶体的合成

研究了水热法合成晶体,浓度配比、生长温度对晶体生长习性的影响.合成了一系列化学计量比的Y_(1-x-0.3)Er_(0.3)Tm_xP_5O_(14)(x=0.01～0.1)晶体,观察和分析了晶体的缺陷及成因,测定和讨论了晶体结构.

Simultaneous enumeration of diatom, protozoa and meiobenthos from marine sediments using Ludox-QPS method

The Ludox-QPS method is a newly developed technique, which combines the Ludox HS 40 density centrifugation and quantitative protargol stain, to enumerate marine ciliates with good taxonomic resolution. We tested the method for simultaneous enumeration of diatoms, protozoa and meiobenthos and compared its extraction efficiency for meiobenthos with that of the routine Ludox-TM centrifugation and a modified protocol using Ludox HS 40. We conducted the evaluation with a sample size of 8.3 ml each from sandy, muddy-sand and muddy sediments collected from the intertidal area of the Yellow Sea in summer 2006 and spring 2007. The Ludox-QPS method not only produced high extraction efficiencies of 97 +/- 1.3% for diatoms and 97.6 +/- 0.8% for ciliates, indicating a reliable enumeration for eukaryotic microbenthos, but also produced excellent extraction efficiencies of on average 97.3% for total meiobenthos, 97.9% for nematodes and 97.8% for copepods from sands, muddy sands and mud. By contrast, the routine Ludox-TM centrifugation obtained only about 74% of total meiobenthos abundance with one extraction cycle, and the modified Ludox HS 40 centrifugation yielded on average 93% of total meiobenthos: 89.4 +/- 2.0% from sands, 93 +/- 4.1% from muddy sands and 97.1 +/- 3.0% from mud. Apart from the sediment type, sample volume was another important factor affecting the extraction efficiency for meiobenthos. The extraction rate was increased to about 96.4% when using the same modified Ludox centrifugation for a 4 ml sediment sample. Besides the excellent extraction efficiency, the Ludox-QPS method obtained higher abundances of meiobenthos, in particular nematodes, than the routine Ludox centrifugation, which frequently resulted in an uncertain loss of small meiobenthos during the sieving process. Statistical analyses demonstrated that there were no significant differences between the meiobenthos communities revealed by the Ludox-QPS method and the modified Ludox HS 40 centrifugation, showing the high efficiency of the Ludox-QPS method for simultaneous enumeration of diatom, protozoa and meiobenthos. Moreover, the comparatively high taxonomic resolution of the method, especially for diatoms and ciliates, makes it feasible to investigate microbial ecology at community level.

祁连山海北高寒湿地40～80cm土壤温度状况观测分析

海北高寒湿地土壤水分达超饱和状态,土体热容量大,因而地温在随时间进程中变化平稳,日、年较差较小. 年内季节冻土并不深厚,多维持于1 m 左右,小于高山草甸土分布区. 由于50 cm 层次年平均地温仅为1. 2 ℃,暖季的6～9 月平均为2. 8 ℃左右. 因此,按温度诊断特点来看,该类型高寒湿地土在中国土壤分类中属寒冷性土壤温度状况,仍为正常有机土.