Preparation and Molecular Structure of Binuclear Nickel (I) Complex Bridged by 1,2,4, 5‐Benzenetetracarboxylato Tetravalent Anion

The title complex [(H₂O)₂(IMI)₃Ni(TCB)Ni(IMI)₃‐(H₂O)₂] H₂O (TCB = 1,2,4,5‐benzenetetracarboxylato te‐travalent anion; IMI = imidazole) has been prepared by the reaction of Ni(IMI)₃(Ac)₂ and TCB in aqueous solution. The crystal structure has been determined by single‐crystal X‐ray diffraction method. It crystallizes in the monoclinic system, space group P2₁/c(# 14), a = 1.2714(4) nm, b = 0.9411 (3) nm, c = 1.5869(4) nm, β= 108.54(2)°, V= 1.8001(9) nm³, Z = 2. The main feature of the crystal structure is a symmetric binuclear unit made up of two slightly distorted coordination octahedrons, which are bridged by TCB in monodentate fashion to each metal ion. Moreover three nitrogen atoms from three imidazoles, three oxygen atoms from two water molecules and one carboxylate group of TCB coordinated to a nickel (I) ion are found on a face of the octahedron respectively, so the octahedron is a facial isomer.     

Synthesis and Photophysical Properties of C60‐carbazole Adducts

Three C₆₀‐carbazole adducts have been synthesized by 1, 3‐dipolar cycloaddition reaction. Intramolecular energy/electron transfer from carbazole to C₆₀ was observed by steady‐state absorption and fluorescence spectra. The fluorescence spectra of these adducts were similar to each other and dependent on the excitation wavelength and solvent.     

Types of saltwater intrusion of the Changjiang Estuary

The Changjiang Estuary is characterized by multi-order bifurcations, unsteady sub-merged sandbars, mid-channel sandbars, creeks and riffles. The following four types of saltwater intrusion are found: (1) direct intrusion from the sea; (2) intrusion during tidal flooding; (3) intrusion from tidal flats overflow; and (4) salt water coming upstream through other waterways. These result in a complicated temporal and spatial salinity distribution. A high chlorinity concentration zone exists from the Liuhekou to the Sidongkou along the South Branch. The salinity during neap tide or ordinary tide is higher than during spring tide.     

离子色谱法快速检测洗涤日用品中的F-、Cl-、SO42-、P3O105-

介绍用离子色谱法快速同时检测洗涤日用品中的F^-、CI^-、SO4^2-、P3O10^5-。选用DIONEX IONPAC AS11作为了离子分离柱,以电导检测器检测,对离子分离条件进行了研究。F^-、CI^-、SO4^2-和P3O10^5-的检出限分别为0．02、0．01、0．01和0．03mg/L ,加标平均回收率分别为94．5％、96．2％、102．2％和97．4％。     

A study on the relationship between iridium concentration in hen eggshell and iridium-enriched feed by NAA

Four hens were fed by adding ammonium hexachloroiridate into their forage. After two weeks, we measured the Ir concentration in three fractions (eggshell, albumen, egg yolk) of their eggs by instrumental neutron activation analysis (INAA). Ir was present in all the three parts of the eggs. Further, the highest concentration of Ir was found in the egg yolk fraction, about 10 times higher than that in the eggshell and albumen. Moreover, the longer the Ir-containing feed was used, the higher the Ir concentration in the egg fractions was. After 4-6 day feeding, the Ir concentration became stable. The experimental results indicated that the Ir concentration was about 2-7·10^-10 g/g in the eggshell fraction compared to 5.6·10^-7 g/g in feed. Therefore, we can estimate the ratio from the feed over the eggshell via gastrointestinal pathway to be about 0.08%. The new result is useful to evaluate the iridium-enriched eggshell fossils of dinosauria and to interpret the origin of the mass extinction of dinosauria at the end of Cretaceous.     

固载蛋白A交联聚甲基丙烯酸缩水甘油酯连续床亲合色谱柱的制备及性能考察

采用沉淀聚法“原位”（in-situ)聚合合成了交联聚甲基丙烯酸缩水甘油酯连续床色谱柱,对其进行化学改性后,分别得到含有11个碳原子间隔臂以及不含间隔臂键合了蛋白A的高效亲合色谱柱。考察了这两种色谱介质的性能,结果表明含有间隔臂的介质有一定的疏水性;对传统制备蛋白配基的亲合色谱介质的合成路线进行了改进;采用不含间隔臂的亲合柱测定了人血浆中人免疫球蛋白G（HIgG)的含量,所测得的定量标准曲线线性相关系数达到0．999;考察了流速对合成的连续床色谱柱柱压的影响,当流速高达9．0mL/min时,柱压也仅为6．5MPa;采用pH梯度对HIgG的不同亚基进行了分离。     

改性钛锆复合氧化物催化环己酮肟气相Beckmann重 排反应

制备了经SO4^2-,PO4^3-,MoO3,WO3和B2O3改性的钛锆复合氧化物(TiO2-ZrO2)催化剂,并用常压连续流动固定床微型反应器考察了它们对环己酮肟气相Beckmann重排反应制己内酰胺的催化性能。结果表明,在反应温度300℃时,B2O3/TiO2-ZrO2具有较高的己内酰胺选择性(97.0%)和收率(96.7%),且明显高于B2O3/TiO2和B2O3/ZrO2催化剂,用N2吸附和NH3-TPD,CO2-TPD等方法对催化剂的经表面积、孔容、孔分布和表面酸、碱性分别进行了测定,讨论了这些物化性能对催化剂活性、选择性和稳定性的影响。     

激光光栅显微图像检测技术及其应用

介绍一种可以用来测量曲面试件表面应分量（εｚ,εθ,εｚθ）的激光光栅显微图像检测技术（ＩＧＭ）,它能实现从小应变到大应变全过程的高精度定量测量。我们将这一技术成功地应用在铁基形状记忆合金（ＦＳＭＡ）管接头的结构设计中,在这项研究中,首先在管接头结构表面制作了变形的载体－位相型干涉光栅,由结构表面产生的衍射光通宵我学系统后形成新的干涉光栅,我们利用数字图像系统接收了逆相变前后各自的干涉图像,采用带     

Nuclear magnetic resonance relaxation studies of polyacrylamide solution

 The cohesive interaction among polymer chains in a polyacrylamide (PAAm)–D₂O solution has been studied by NMR relaxation. The NMR relaxation times of PAAm in the good solvent D₂O were measured at different temperatures. The results show that the solution system has a high local viscosity and that its relaxation characteristic is soft-solid-like. The temperature dependence of the relaxation behavior of the solution is obviously different from that of ordinary polymer solutions. The difference lies in the relaxation behavior of the methylene protons in the main chain of PAAm, as shown by analyzing the relaxation process with single exponential and biexponential decays. As the temperature increases, the solvation is weakened, leading polymer chains to form curling coils, thus hindering the movement of the methylene protons among the main chains. It can be expected from the existence of 80% fast-relaxing protons that there are a zhigh number of entanglements among the polymer chains in PAAm solution. The information about entanglements among the polymer chains can be deduced from the biexponential dependence of the spin–spin relaxation on the concentration of the polymer solutions. Received: 14 April 1999/Accepted in revised form: 12 October 1999     

双金属氰化物配合物(DMC)催化剂的制备及表征

分别以乙二醇二甲醚,二乙二醇二乙和１,４－二氧六环为有机配体,制备了一系列双钓饵鹅的催化剂;用Ｘ射线衍射（ＸＲＤ）和Ｘ射线光电子能谱（ＸＰＳ）技术,研究了催化剂的晶相结构和表面状态。结果表明,钻以原料Ｚｎ３〖Ｃｏ（ＣＮ６）【２．ｘｈ２Ｏ中的物种形式存在,在催化剂的制备过程中没有氧化还原反应发生,有机 本只与锌离子配位,这 与位作用破坏了Ｚｎ（２〗Ｃｏ（ＣＮ）６〖２．１２Ｈ２的晶体结构,催化剂的表面