混合线性分析-分光光度法同时测定微量铁和铝

研究将混合线性分析（ｈｙｂｒｉｄ ｌｉｎｅａｒ ａｎａｌｙｓｉｓ，ＨＬＡ）用于光谱分辨同时光度测定Ｆｅ３＋和Ａｌ３＋。在碱性条件下，Ｆｅ３＋和Ａｌ３＋与水杨基荧光团生成光谱相互重叠的有色络合物，其浓度在０～３２０　ｇ／Ｌ Ｆｅ３＋和０～１６０ｇ／Ｌ Ａｌ３＋范围内与吸光度呈良好线性关系。在５５０ｎｍ～６３０ ｎｍ内取４１个波长测量７组标准混合溶液的吸光度作为校正集，用最小二乘法求得的系数矢量作为各组分的纯光谱。以ＨＬＡ法进行数据处理，在Ｆｅ３＋：Ａｌ３＋浓度为１０：１～１：８范围内测定回收率为９３．３％～１０７．５％。将本法与偏最小二乘法（ＰＬＳ）法进行了比较，本法获得了较好的准确度和精密度。

叔丁基取代的环戊二烯基钛、锆、铪二氯化物的合成及催化乙烯聚合

(tBuC5H4 ) 2 MCl2 (M =Ti(1a) ,Zr(1b) ,Hf(1c) )和 (tBu2 C5H3 ) 2 MCl2 (M =Ti(2a) ,Zr(2b) ,Hf(2c) )可以通过单叔丁基环戊二烯基锂或双叔丁基环戊二烯基锂与MCl4 (M =Ti,Zr,Hf)在四氢呋喃中反应制备得到 ,用IR、1H NMR和EI MS对这些化合物进行了表征 .采用X光单晶结构分析测定了 (tBuC5H4 ) 2 HfCl2 的晶体结构 .六个化合物均具有一定的催化乙烯聚合活性

X-ray photoelectron spectroscopy and mass spectrum of organic tin compounds

The relationship between the chemical displacement of the binding energy and the different chemical environment for 12 organic tin compounds was studied by means of X-ray photoelectron spectronscopy. The different substituents in the compounds have influence on the tin outer electron and Sn-O bond, which was discussed by Xray photoelectron spectroscopy and mass spectrum.

Calculation of second-order nonlinear optical coefficients of KTiOPO4 and KTiOAsO4

The second-order nonlinear optical tensor coefficients of both KTiOPO4 (KTP) and KTiOAsO4 (KTA) are calculated from the chemical bond viewpoint. All constituent chemical bonds of both crystals are considered, and contributions of each type of bond to the total linearity and nonlinearity are determined. Calculated results agree satisfactorily with experimental data in both signs and numerical values. The calculation shows that though TiO6 groups and P(1)O-4 or As(1)O-4 groups have relatively larger linear contributions, they can only produce an advantageous environment for KOx (x = 8, 9) groups and P(2)O-4 or As(2)O-4 groups in nonlinear optical contributions. The origin of nonlinearity of KTP family crystals comes from the KOx (x = 8, 9) and P(2)O-4 groups in their crystal structures. Furthermore, the difference in optical nonlinearities of KTP type crystals is analyzed, based on the detailed calculation of nonlinearities of both KTP and KTA. (C) 1999 Academic Press.

有机锡化合物的光电子能谱和质谱研究Ⅲ

本文利用光电子能谱(XPS)和质谱(MS)研究了12种有机锡化合物。通过XPS和MS讨论了化合物中取代基对锡内层电子的影响及对SnO键的影响。结果表明XPS和MS对有机锡化合物某些化学键性质的讨论具有互补性。

不同偶联剂对滑石粉表面改性填充ABS树脂的研究

本文研究了滑石粉经长链硅烷偶联剂820J,硅烷偶联剂KH—570,铝酸酯偶联剂DL—411表面改性后,对填充ABS树脂的加工行为和力学性能的影响,结果表明长链硅烷偶联剂820J对填充ABS复合体系缺口冲击强度的提高有明显的促进作用。

Generation of chiral bis(cyclopentadienyl)neodymium Schiff base complex bearing internal C-C bond formation and hydrogen transfer

NdCl3 reacts with excess CpNa (Cp=Cyclopentadienyl) in THF, followed by sequent treatment with (S)-(+)-N-(1-phenylethyl)salicylideneamine led to the formation of title compound, [GRAPHICS] The X-ray structure determination shows that it is a dimer with internal C-C bond formation and hydrogen transfer between one of Cp ring and the C=N bond of Schiff base ligand. (C) 1997 Elsevier Science S.A.

Electrochemical behavior of Nd3+ and Ho3+ in LiCl-KCl eutectic melt

The electrochemical behavior of Nd3+ and Ho3+ ions on molybdenum electrode in the LiCl-KCl eutectic melts has been studied by cyclic voltammetry and open-circuit potentiometry. The results show that the reduction process of Nd3+ and Ho3+ ions on molybdenum electrode is one-step three electron reversible reaction. The diffusion coefficients of Nd3+ and Ho3+ ions are 1.13 x 10(-6) cm(2).s(-1)(450 degrees C) and 2.142 x 10(-5) cm(2).s(-1)(450 degrees C), respectively. The measured standard electrode potential of Ho3+/Ho is 2.987 V(vs. Cl/Cl-), being more negative than the theoretical one, the reason of which is also discussed.

蛋白质分子三维结构能量优化途径的选择

NMR方法是研究溶液中蛋白质的三维结构的重要手段，本文以BUSHIIA为例，对用度量矩阵距离几何法获得的初始三维结构进行了能量优化，主要探讨了蛋白质分子三维结构能量优化途径的选择问题．本文把优化过程分为三个阶段，分别采用不同的优化方式，使分子结构得到优化，对于分子量在8000左右的蛋白质而言，本方法能够获得较好符合核磁实验约束条件的分子低能构象.

Synthesis and characterization of acetacetic derivatives of flullerene

Acetacetic derivatives of fullerene were obtained by the reaction of C-60 with acetacetic ester, after separation with silica gel column chromatography, in good yields. Fullerenols with 13-15 hydroxyl groups were-isolated as the by-products of this reaction. Detailed experimental conditions and the structural characterizations of these new compounds were discussed.

Magnetic and electric properties of Bi(La)Sr(Ca)Mn2O6

Bi1-xLaxSrMn2O6 and BiSr1-xCaxMn2O6 are prepared by solid state reaction. They are n-type semiconductors with ferromagnetism at room temperture. When Bi is substituted partly by rare earth, a negative magnetoresistance effect is observed in the pellet of Bi1-xLaxSrMn2O6. There are semiconductor-metal transitions at 820 K in BiSrMn2O6. The transitions are attributed to the magnetic transition at high temperature. The substitution of Ca for Sr makes the transition temperature increase. However, when Bi is partly substituted by La, the solid solution does not change into metal. (C) 1996 Academic Press, Inc.

Dynamic spectroelectrochemical measurement for the conformational transition of cytochrome c induced by bromopyrogal red

The conformational transition of horse heart cytochrome c induced by bromopyrogal red (BPR) in very low concentration has been firstly investigated by dynamic spectroelectrochemical technique, both at the BPR adsorbed platinum gauze electrode and at a bare platinum gauze electrode in a solution containing BPR. The effect of BPR on the structure of cytochrome c was studied by UV-visible and Fourier transform IR spectroscopy. The unfolded cytochrome c behaves simply as an electron transfer protein with a formal potential of -142 mV vs. a normal hydrogen electrode. The difference between the formal potentials of the native and unfolded cytochrome c is coupled to a difference in conformational energy of the two states of about 40 kJ mol(-1), which agrees well with the result reported. The stability and slow refolding of the unfolded cytochrome c are discussed.

聚芳醚砜薄膜的气体透过行为

研究了一系列聚芳醚砜的Ｈ２、ＣＯ２、Ｏ２、Ｎ２和ＣＨ４气体透过性能，讨论了其气体透过的温度依赖性．与双酚Ａ聚砜（ＰＳＦ）相比，几种新型聚芳醚砜的气体透过系数和气体选择系数同时有所提高．通过聚合物的分子链段活动性和自由体积数据系列变化，讨论了气体透过速率与分子结构的关系。

EBV法制备Znln_2S_4薄膜的性质研究

用电子束加热真空蒸发法（ＥＢＶ法）制备了厚度为３５０ｎｍ的ＺｎＩｎ２Ｓ４薄膜。研究了最佳成膜工艺条件和最新电子能谱分析结果；通过不同气氛处理可以控制材料的导电类型，典型膜的电阻率为２．５×１０－１Ω·ｃｍ，Ｈａｌｌ迁移率为５２ｃｍ２·Ｖ－１·ｓ－１，载流子浓度为１．４２×１０１７ｃｍ－３，禁带宽度为２．１３ｅＶ。探讨了ＺｎＩｎ２Ｓ４膜的导电机理，并制作了ＺｎＩｎ２Ｓ４－Ｓｉ太阳电池。

STUDIES ON RADIATION CROSS-LINKING OF FLUOROPOLYMERS

The research work on radiation modification of a series of fluoropolymers were performed . The radiation crosslinked fluoropolymers obtain a great improvement in high temperature resistance, high temperature mechanical properties and radiation stability.