无水醋酸镍与水杨醛肟固相配位反应的热化学研究

用新型的具有恒定温度环境的反应热量计，以６ｍｏｌ·ｄｍ－３ＨＣｌ溶液为量热溶剂，分别测定了ＨＳＡＯ，Ｎｉ（Ａｃ）２和Ｎｉ（ＳＡＯ）２，ＨＡｃ先后溶于该溶剂的溶解焓．设计了一个新的热化学循环，计算得到该配位反应的反应焓ΔｒＨ＝－８６．０７５ｋＪ·ｍｏｌ－１，并估算出了ΔｆＨ［Ｎｉ（ＳＡＯ）２，２９８Ｋ］＝－４０１．３３６ｋＪ·ｍｏｌ－１．     

铕－邻菲罗啉－甲基苯甲酸二、三元配合物的NMR研究

本文报道了希土铕（Ｅｕ３＋）与甲基苯甲酸（包括邻位０－ＭＢＡ．间位ｍ—ＭＢＡ，对位ｐ－ＭＢＡ）及邻菲罗咐（Ｐｈｅｎ）形成的二元和三元固体配合物的制备，对它们进行了元素分析，确定该配合物的组成为：二元：Ｅｕ（ＣＨ３Ｃ６Ｈ５ＣＯＯ）３，三元：Ｅｕ（ｐｈｅｎ）（ＣＨ３Ｃ６Ｈ５ＣＯＯ）３．对上述配合物的结构作了核磁共振氢谱（１ＨＮＭＲ）和碳谱（１３ＣＮＭＲ）的研究，并用红外光谱（ＩＲ）作了进一步确定．     

用交流阻抗法研究某些离子选择电极的响应特性

用交流阻抗法研究了两种液膜胆R汁酸电极和两种聚氯乙烯(PVC)膜钙离子选择电极. 从体电阻R_b和电荷传递电阻R_(ct)得到膜内离子迁移活化能E_a, 及电极的表观标准交换电流密度i°_0等信息. 结果表明: E_a比R_b更能反映离子在膜内迁移的情况, 离子在PVC膜中的迁移比在液膜中困难得多; i°_0能在一定程度上反映电极性能的优劣等。     

Dawson型磷钨酸催化合成乳酸月桂醇酯

用Dawson型磷钨酸催化合成乳酸月桂醇酯。实验结果表明:Dawson型磷钨酸有较高的催化活性,反应时间短,酯收率高,工艺简单。最佳工艺条件为:醇/酸摩尔比为1.5:1,催化剂用量为0.3%,带水剂甲苯体积(mL)与反应物质量(g)之比为0.4:1~0.5:1,反应温度为115~140℃,反应时间30~50min。在此条件下,酯收率可超过93% 。     

Debye screening for two-dimensional Coulomb systems at high temperatures

The grand canonical ensemble of a two-dimensional Coulomb system with±1 charges is proved to have screening phenomena in its high-temperature region. The Coulomb potential in a finite region is assumed to be (–)^–1, where is the Laplacian with zero boundary conditions on. The hard-core condition is not assumed. The model is set up by separating (–)^–1 into a shortrange part and a long-range part depending on a parameter. The self-energies are subtracted only for the short-range part and therefore a choice of is a choice of subtraction of self-energies. The method of proof is in general the same as that of Brydges-Federbush Debye screening, except that here a modification for the short-range part of the potentials is needed.     

Mössbauer study on surface magnetic properties in magnetic fluids

The presence of m=0 lines of the Mössbauer spectra of small Fe₃O₄ particles coated with an organic surfactant in an applied field of 7 T at 5 K shows a non-collinear magnetic structure in the surface layer of these particles. From the temperature dependence of the hyperfine field, the anisotropy constantK was calculated.Projects supported by the Science Fund of the Chinese Academy of SciencesNow working at the Shanghai Institute of Education     

A new C21-steroidal glycoside from Cynanchum stauntonii

A new C21-steroidal glycoside with two known compounds were isolated from the root of Cynanchum Stauntonii.Based on thespectral analysis,including MS,1H NMR,13C NMR,DEPT,1H-1H COSY,13C-1H COSY,HMQC and HMBC,their chemicalstructures were determinated as glaucogenin-C 3-O-a-L-cymaropyranosyl-(1→4)-b-D-digitoxopyranosyl-(1→4)-β-D-canaropyranoside(1),stigmasterol(2)and ursolic acid(3).