Synthesis and Molecular Recognition of Novel Cleft-type Receptors

A novel type of molecular cleft has been designed and synthesized from estrogen and approprite spacer groups such as xylylene or pyridine dimethylene. These receptor compounds 1a-d and 2a-d have been characterized by Mass spectra,¹H-NMR spectra,IR spectra and elemental analyses. The structures of the receptors are shown in scheme 1. Their molecular recognition properties for the aromatic amine and aromatic amino acids have been investigated by UV-visble spectrophotometric titration. The titration data were analyzed by using the Benesi-Hildebrand equation^[1].     

FePc结构对Pd(OAc)2/HQ/FePc催化环己烯氧化活性的影响

在乙腈酸性水溶液中,不同来源酞菁铁(FePc)和Pd(OAc)2/HQ（氢醌）组成的催化体系在环己烯氧化反应中有明显不同的催化活性.通过IR、Mssbauer、XPS、XRD、SEM、BET等技术对酞菁铁的分析表明,由酞菁铁组成的多组份催化体系的催化活性与酞菁铁中的飒 氧酞菁铁含量、酞菁铁结晶度和表面形态有关.     

新型Zr-Ti-Cu-Ni-Be-Fe大块非晶合金的形成及性能 *

报道了新型块状、高强度Zr-Ti-Cu-Ni-Be-Fe非晶合金的形成及物性的研究结果 ,研究了铁原子组元对Zr-Ti-Cu-Ni-Be-Fe大块非晶形成能力、硬度、磁化率及热稳定性的影响 ,探讨了铁在这种大块非晶合金形成中所起的作用 .     

A note on the independent domination number of subset graph

The independent domination number i(G) (independent number (G)) is the minimum (maximum) cardinality among all maximal independent sets of G. Haviland (1995) conjectured that any connected regular graph G of order n and degree 1/2n satisfies i(G) 2n/3 1/2. For 1 k l m, the subset graph S _m (k, l) is the bipartite graph whose vertices are the k- and l-subsets of an m element ground set where two vertices are adjacent if and only if one subset is contained in the other. In this paper, we give a sharp upper bound for i(S _m (k, l)) and prove that if k + l = m then Havilands conjecture holds for the subset graph S _m (k, l). Furthermore, we give the exact value of (S _m (k, l)).This work was supported by National Natural Sciences Foundation of China (19871036).     

Investigation of the EPR parameters and local structures for Cu2+ in Bis(l-asparaginato) M(II) catalysts (M=Zn,Cd, Mg)

The electron paramagnetic resonance (EPR) parameters (g factors and hyperfine structure constants) for Cu²⁺ in Bis(l-asparaginato) M(II) catalysts (M=Zn, Cd, Mg) are theoretically investigated using the high order perturbation formulas of these parameters for 3d⁹ ions in orthorhombically elongated octahedra. Ligand orbital and spin–orbit coupling contributions are included from the cluster approach in view of strong covalency. The ligand octahedra (i.e., [CuO₄N₂]^12? clusters) are found to experience axial and perpendicular local bond length variations Δ (≈0.19–0.25 Å) and δ (≈0.12–0.14 Å) due to the Jahn–Teller effect and size mismatch, which are dissimilar to those of host M²⁺ sites in pure compounds. The theoretical EPR parameters based on the above local structures show good agreement with the observed values, and some improvements are achieved as compared with those in the previous work. The local structures of these centers are discussed.     

胆汁酸选择脱氧的新方法

胆汁酸选择脱氧的新方法李开喜，徐正邦，余锐，赵华明（四川大学化学系，成都６１００６４）关键词胆汁酸；冠醚；钾；脱氧反应；自由基醇的自由基脱氧方法在天然产物的合成中受到普遍的重视［１］．Ｄ．Ｈ．Ｒ．Ｂａｒｔｏｎ等［２］发现化合物中两个羟基经双酯化后用碱...     

Theoretical studies of the local structures and electron paramagnetic resonance parameters for Cu2+ center in Zn(C3H3O4)2(H2O)2 single crystal

The electron paramagnetic resonance (EPR) parameters (g factors g_xx, g_yy, g_zz and hyperfine structure constants A_xx, A_yy, A_zz) are interpreted by taking account of the admixture of d-orbitals in the ground state wave function of the Cu²⁺ ion in a Zn(C₃H₃O₄)₂(H₂O)₂ (DABMZ) single crystal. Based on the calculation, local structural parameters of the impurity Cu²⁺ center were obtained (i.e. R_a≈1.92 Å, R_b≈1.96 Å, R_c≈1.99 Å). The theoretical EPR parameters based on the above Cu²⁺?O^2? bond lengths in the DABMZ crystal show good agreement with the observed values and some improvements have been made as compared with those in the previous studies.     

氧空位对多孔氧化锆光学性质的影响

以多孔氧化锆(ZrO2)材料的制备与光学性质为基础,讨论了氧空位对光学发光性能的影响及氧化锆发光性质的位形坐标图.以水热法制备的多孔ZrO2粉体具有由结晶不完整的ZrO2颗粒堆积而成的多孔结构,产物的比表面积达151.9m2·g-1.检测了样品的光吸收和光致发光(PL)性能,并用解卷积方法对样品的光致发光谱进行了分析,发现了不同于以前的结果.多孔ZrO2的主要光致发光峰位于蓝紫色光区,而经过H3PO4处理后的样品的发光峰红移至蓝绿色发光区,样品的多孔结构和磷的存在并不能使ZrO2中产生新的发光峰.分析结果显示氧空位在产物中形成一个新的能级,在发光性质中起着捕获电子形成色心而导致荧光发光的作用.     

售后赔偿纠纷中的最终报价仲裁研究

在商品消费领域,售后赔偿纠纷问题越来越普遍,解决这些纠纷问题常常耗时耗力,效率低下。本文针对这一情形,研究了如何使用最终报价仲裁方法来解决这类问题。在最终报价仲裁方法里,仲裁人有一个自己的理想裁决值。我们根据现实情况,讨论了协商双方认为仲裁人的理想裁决值所可能发生的三种情形;然后基于争议双方的期望效用最大化原则,从理论上分析了不同情形下协商双方的最优报价策略。本文提出的结论可对实际的仲裁问题提供有效的参考。