YBa2Cu3O—7超导体中钡的价态

对于YBa_2Cu_3O_(～7)超导体的Ba 3d X光电子能谱(XPS)存在分裂(出现肩峰)的现象有很多不同的解释.Kohiki等认为主峰和肩峰分别代表晶格Ba~(2 )离子和金属Ba;Han等则认为它们分别代表Ba~(2 )离子和更高价态的Ba离子;Ji等提出超导体中存在Ba~(2 )和Ba~((2-δ) )两种离子;唐有祺等报道超导体存在体相钡、表面BaCO_3的钡和绝缘相中的钡,它们的Ba 3d_(5/2)结合能分别为777.8,779。7和781.5eV;Fjellvag等也观察到Ba3d谱中出     

钡离子选择性膜电极的研制

近年来应用中性载体作为Ba~(2+)离子选择性的活性物质,已有了较多的研究。本文将着重讨论非离子型表面活性剂,三(苯乙基)苯基聚氧乙烯基醚为活性物质的钡电极的某些性能。电极可直接用于Ba~(2+)离子的电位测定,以及在各种能与Ba~(2+)离子形成沉淀的哪些阴离子(SO_4~(2-)、CrO_4~(2-)、C_2O_4~(2-)等)的滴定中作为指示电极。实验部分 1.电极的响应时间和稳定性:电极插入10~(-2)M的BaCl_2溶液中,观察电极的电位值随时间的变化。实验结果,电极的响     

果糖-水混合溶液中多组分电解质热力学

恒定混合溶液总离子强度I=1.0000 mol•kg－1,改变果糖-水混合溶液中果糖的质量分数w=2.5％、5.0％和7.5％的条件下,应用电动势方法测定下列无液体接界电池(A)和(B)在278.15、283.15、288.15、293.15、298.15、303.15、308.15、313.15、318.15 K等9个温度下的电动势: Pt, H2 (105 Pa)│HCl(m), C6H12O6(w), H2O(1－w)│AgCl-Ag (A) Pt, H2 (105 Pa)│HCl(mA), NaCl(mB), C6H12O6(w), H2O(1－w)│AgCl-Ag (B) 根据测得电池的电动势,计算出混合溶剂中AgCl-Ag电极的标准电极电势和HCl的标准迁移吉布斯自由能、迁移熵和迁移焓; 求出四元混合溶液中HCl的活度系数γA.结果表明在溶液中总离子强度I保持恒定,HCl的活度系数服从Harned规则,进一步讨论了混合物中HCl的介质效应.     

用~(23)Na NMR研究冠醚与钠离子的配位反应动力学

作者在一系列工作中研究了在苯并-18-冠-6的醚环上引入甲基后对碱金属,碱土金属离子配位反应的影响,前文用~(23)Na NMR谱研究了钠离子和若干冠醚配合物的稳定性随甲基数目的增加而线性地减少.本文用NMR谱探索了2,3-苯并-11-甲基-18-冠-6(BC1-18C6)与钠离子配位反应.Shchori等曾在Na~+浓度为0.3--1.9mol·dm~(-3)的范围内,用LiSCN维持离子强度,研究了二苯并-18-冠-6(DB-18C6)和钠离子的反应动力学,他们发现     

含嘧啶环的双冠醚——Ⅲ.用双冠醚作载体的PVC膜离子选择性电极性质的研究

合成了九种用嘧啶环桥联的新的双冠醚,其中分别含有苯并-12-冠-4、(1、47)、苯并-15-冠-5(2、5、8)和苯并-18-冠-6(3、6、9 )。用它们作为载体分别制成钠、钾和铯离子选择性电极,测定了电极的选择性系数。结果表明,电极(7)(8)(9)具有较好的性能。     

用预浓集分离中子活化分析法测定海水中微量铀

以二苯基-16冠-5-氧代氧肟酸(HL)作为一种新型萃取剂,研究了对U(VI),Na~+,K~+,Sr~(2+),Ba~(2+)和Br~- 等离子的萃取.结果表明,在一定条件下,U(VI)可以定量地被萃取,而Na~+,K~+,Sr~(2+),Ba~(2+)与Br~-等其它离子则几乎全部留在水相.在萃取过程中,HL与U(VI)形成了组成为2:1的萃合物.并建立了自海水中浓集和分离铀的方法,将它与中子活化分析技术相结合,满意地实现了海水中微量铀的测定.     

用于渗透气化法分离水—乙醇混合物的含离子膜

合成了乙烯醇和顺丁烯二酸的交替共聚物,并制成膜,使其与BaCl_2,CaCl_2,SrCl_2及CuSO_4的水溶液反应。将反应产物—含离子聚合物膜用于渗透气化法分离乙醇-水混合物。结果表明,离子膜在渗透速率及分离系数两方面均好于纯聚合物膜。在以上四种离子膜中,含Ba~(2 )离子膜的性能最好,这表明Ba~(2 )离子不仅使膜更加亲水,增加了对水的溶解度,而且由于Ba~(2 )离子引起聚合物分子链间的交联,而使膜变得更加致密,从而提高了膜的分离系数。     

酚醛冠醚共缩聚物的合成与性能

用2,6-二羟甲基-4-苯基苯酚分别与二苯并-18-冠-6(2B18C6)、二苯并-24-冠-8(2B24C8)、二苯并-30冠-10(2B30C10)、苯并-15-冠-5(B15C5)、苯并-18-冠-6(B18C6)缩聚合成了五种酚醛型冠醚共聚物。我们用聚冠醚的氯仿溶液萃取苦味酸碱金属盐水溶液,研究了它们对金属离子的络合性能。结果表明,聚冠醚(PB15C5)和(PB18C6)的萃取能力和选择性显著优于相应的单冠醚。     

水合二苯并-18-冠-6四溴合铟(Ⅲ)酸钾K(DB18C6)2InBr4·H2O配合物的晶体结构

合成了二苯并-18-冠-6四溴合铟(Ⅲ)酸钾配合物,由元素分析确定该配合物的化学式为KInBr_4(C_(20)H_(24)O_6)2·H_2O,用X射线单晶衍射测定了该配合物的结构,晶体属单斜晶系,空间群C_2h~5—P2_1/n,晶胞参数为a=8.727(5),b=26.051(13),c=20.470(13),β=92.73(5)°,z=4,In(Ⅲ)与Br~-形成InBr_4~-配阴离子,K~+与一个二苯并-18-冠-6(DB18C6)以及一个水分子直接配合,配位数为7,另一个DB18C6以未被配合的分子形式存在于晶体中,水合二苯并-18-冠-6四溴合铟酸钾配合物晶体结构测定的实验结果为阐明在相应的萃取体系中DB18C6萃取KInBr_4的机理提供了必要的理论依据。     

固相萃取-离子色谱法分析胺液中的热稳态盐离子组成

建立了固相萃取(SPE)-离子色谱(IC)法测定脱硫胺液中热稳态盐(HSS)离子的分析方法,优化了萃取上样量、流速、解吸溶剂等条件。Cl-、2－4SO、SCN-、HCOO-、H3CCOO-和H3CH2CCOO-的检出限为0.02×10-6(w),0.1×10-6(w),0.4×10-6(w),0.002×10-6(w),0.15×10-6(w),0.4×10-6(w),相对标准偏差(RSD,n＝6)为3.2%～7.6%。同时建立了离子交换-容量法分析胺液中的热稳态盐分析方法,对离子交换和固相萃取两种处理样品的方法进行了对比,SPE法检出限低而且重复性好。采用SPE-IC和离子交换-容量法,对实际胺液样品进行分析对比,实验结果表明当胺液中HSS的含量大于1%时,采用容量法简单快速;当HSS的含量小于1%时,采用固相微萃取法-离子交换法比较准确。     

HEPT类化合物的QSAR研究

为定量结构／活性相关性研究提取了量子化学参数,拓扑指数Am,分子连接性指数^mxt及疏水性常数,同时应用正交变换和最佳变量子集算法（Leaps-and-Bonds)进行了变量压缩和选择,进而实施了多元回归分析,并由此结果进行了HEPT类化合物（1－[(2-hydroxyethoxy)methyl]-6-(phenylthio)-thymine derivatives)的结构／活性关系的理论解释,进行了人工神经网络法对于该类化合物的活性预测,其结构明显好于多元回归法。     

From the Micro- to the Macro-: Managing the Conservation of the Warship,Vasa

Sweden's famous warship, Vasa, sank on her maiden voyage in August 1628, and remained on the bottom of Stockholm harbour for 333 years. Raised in 1961, she became the first large-scale wooden object to be treated with polyethylene glycol (PEG). In the summer of 2000 a number of acidic salt precipitations were noticed on the surface of the ship and on wooden artefacts in the storerooms. An international research project has been established to look into the causes of this problem and suggest possible re-treatments. Meanwhile projects are underway to monitor movements in the ship, to build a better support system, and to replace the thousands of iron bolts holding the structure together, while a sophisticated new climate system has recently been installed in the museum.     

液滴荧光传感与计算机联用技术在微量分析中的应用

通过在LS55型荧光-磷光-发光分光光度计上加装液滴产生及调节附件,采用计算机采集与分析处理数据,成功地研制了双通道液滴光化学传感装置.利用葡聚糖凝胶对复合维生素B中不同组分的选择性吸附来达到分离与同时检测的目的,并将其用于复合维生素B药片的分析,取得了满意的结果.     

On the scaling of the interface energy of the liquid clusters in the disordered nanoporous medium

Similarity of the extrusion curves of non-wetting liquid in a nanoporous medium with different initial fill volume fractions is observed experimentally. The similarity can be explained by the scaling of the interface energy and the self-similarity of the infinite percolation cluster of fluid-filled pores. Understanding the physical processes leading to the observed phenomena is a foundation for the development of high-performance devices for damping and energy storage on the basis of such heterogeneous systems.     

光亮剂对银电沉积行为的影响

用电势阶跃法和旋转圆盘电极法 (RDE)以及SEM和XRD测试手段 ,初步研究了光亮剂对氰化体系中银电沉积行为的影响 .研究表明 ,光亮剂的加入并未导致银电沉积成核机理的改变 ,但显著增强了镀液的微观平整效应 ,并且所得镀层的表观光滑程度明显改善 .XRD测试亦同时表明光亮剂的加入并未改变镀层的择优取向     

Using of the Agglomeration-in-liquid for the Technology of the Fine Materials

The content of the fine and ultrafine particles in the raw material results in difficulty of the separation, the loss of the valuable components and ecological contamination. Secondary using of the fine particles is impossible without their granulation. This problem has been solved by the agglomeration-in-liquid method.An agglomeration-in-liquid method is a process to produce agglomerates in a liquid phase from solid particles suspended in the liquid. The surface of solid particles and the binding liquid must be of identical polarity, but the continuous phase must be of the opposite polarity. The water solutions of the surfactant are the binding liquids or the organic liquids.     

On the dependence of the critical supersaturation on the initial undersaturation in the reverse Wilson chamber

The dependence of the critical supersaturation on the degree of the initial undersaturation has been analyzed in detail.This dependence is explained by means of the Richarch-Powell equation, taking into account the dependence of the -ratio upon the partial pressures of the inert gas and the liquid under investigation.     

Copper-containing dendromesogens: the influence of the metal on the mesomorphism

The synthesis and liquid crystalline behaviour of the first and second generations of a dendrimeric structure based on poly(propyleneimine)(DAB-dendr(NH₂)_x) are reported. 4-(4-n-Alkoxybenzoyloxy)salicylaldehydes are used as mesogenic moieties attached at the peripheral amino groups of the dendrimers giving rise to dendromesogens with four and eight mesogenic branches. From these dendromesogens, considered as organic ligands, were prepared six metal-containing dendrimers which incorporate two or four copper atoms in their structures. All the dendrimeric ligands and three of the metal-containing dendrimers exhibit liquid crystalline properties which were studied by optical microscopy, DSC, X-ray diffraction and EPR spectroscopy.     

Behavior of the Surface Tension and the Viscosity in the Eutecticregion of the Liquid Feb alloy

Abstract

Thermodynamic and transport properties of pure liquid metals show interesting correlations near the melting temperature. This is well known for the case of the surface tension σ and the shear viscosity η In this paper we investigate the possible extension of these correlations to binary alloys, taking the FeB alloy as a case study. Based on literature data we analyze the variation of σ and η as a function of temperature and concentration in a deep eutectic region of the phase diagram of this alloy, as well as the possible correlations between those two quantities. Substantial differences with respect to the behavior in pure metals are found.     

An improvement of the resolution of the identity approximation for the formation of the Coulomb matrix

A straightforward modification of the resolution of the identity (RI) approximation to the Coulomb interaction is described. In the limit of basis sets that are dominated by high angular momentum functions the observed speedups in realistic test systems reach a factor of 2 compared to the standard RI algorithm, and a factor of up to 300 compared to the standard algorithm to form the Coulomb matrix. More moderate savings on the order of 0-20% are obtained for the more commonly used smaller basis sets. A series of test calculations is reported to illustrate the efficiency of the algorithm.