[n—CnH2n＋1NH3]2ZnCl4配合物相变研究

采用差示扫描量热法(DSC)和热重法(TG),研究了〔n-C_nH_(2n 1)NH_3〕_2ZnCl_4(n=9～12)配合物的热稳定性和固-固相变。该系列配合物的分解反应活化能和热稳定性基本上不随烷基链长而变化。配合物在280～370K存在固-固相变。相变数目表现出奇偶效应。相变热焓ΔH和熵ΔS随着烷基链长的增加而线性增大。主转变的峰值温度随烷基链的增长而升高,相应的相变被归属为烷基铵链的结构相变。     

Graphs isomorphic to subgraphs of their iterated line graphs

A graphG is said to be embeddable into a graphH, if there is an isomorphism ofG into a subgraph ofH. It is shown in this paper that every unicycle or tree which is neither a path norK _1,3 embeds in itsn-th iterated line graph forn1 or 2, 3, and that every other connected graph that embeds in itsn-th iterated line graph may be constructed from such an embedded unicycle or tree in a natural way. A special kind of embedding of graph into itsn-th iterated line graph, called incidence embedding, is studied. Moreover, it is shown that for every positive integerk, there exists a graphG such that (G) = , where (G) is the leastn1 for whichG embeds inL ⁿ(G).     

Design, synthesis and bioactivity of novel ALS inhibitors (V)

By means of the X-ray diffraction method, quantum pharmacology analysis and quantitative structure-activity relationships (QSAR) analysis, the structure-activity relationships of the herbicidal sulfonylureas and fused heterocyclic sulfonamides were systematically studied. The results showed that the structure-activity relationships of these two kinds of herbicides were identical and that the heterocyclic ring and sulfonyl moiety in the molecules were their pharmacophores which likely bind in the same receptor sites of acetolactate synthase (ALS). According to these results, the initial model of these two kinds of herbicides binding with the receptor was put forward. Project supported by the National Natural Science Foundation of China (Grant No.29472056).     

Operators on Sobolev Type Spaces

In this paper, we introduce the work done on Hardy-Sobolev spaces and Fock-Sobolev spaces and their operators and operator algebras, including the study of boundedness, compactness, Fredholm property, index theory, spectrum and essential spectrum, norm and essential norm, Schatten-p classes, and the $C^∗$ algebras generated by them.     

On a problem of Axler, Cuckovic and Rao

In this note we show that if two Toeplitz operators on a Bergman space of the (Levi) pseudoconvex domain commute and the symbol of one of them is analytic and non-constant, then the other one is also analytic. This gives an affirmative answer of a problem of S. Axler, Z. Cuckovic and N. V. Rao (1999).

     

BOUNDED COMPOSITION OPERATORS ON HARDY SPACES (II)

In this paper, the characterization of semi-Fredholm composition operators from H2(Bm) to H2(Bn) is given. As an application of the composition operators, the extension properties of analytic maps are discussed.     

示差光谱分析在作物残体腐解研究中的应用

采用示差光谱法对玉米叶片残体腐解过程进行了研究,并与常规谱进行了比较。结果表明,用示差光谱可以省去从腐解有机物中除去无机物的纯化过程,得到的红外光谱清晰可辨。     

Synthesis and properties of novel α‐(1,2,4‐triazolo[1,5‐a]pyrimidine‐2‐oxyl)phosphonate derivatives

In an attempt to discover novel compounds with high activity and low toxicity, a series of new phosphonate derivatives containing triazolo[1,5‐a]pyrimidine moieties have been designed and synthesized by a nucleophilic substitution between α‐hydroxyphosphonates and 2‐methanesulfonyl‐1,2,4‐triazolo[1,5‐a]pyrimidines. The structures of all compounds prepared were confirmed by elemental analyses and by NMR and MS spectroscopy. The results of preliminary bioassay indicate that the title compounds possess certain selective herbicidal activity against rape and also, to some extent, inhibit of acetolactase synthase activity. © 2000 John Wiley & Sons, Inc. Heteroatom Chem 11:313–316, 2000     

铁的自旋转变对菱镁矿热力学性质的影响

含铁菱镁矿(Mg,Fe)CO3是碳进入地球深部的主要载体之一,铁的进入会引起矿物物理性质的变化。采用第一性原理计算方法,研究了菱镁矿含铁及铁的自旋转变对菱镁矿热力学性质的影响。含铁菱镁矿的低自旋态体积比不含铁菱镁矿小;高自旋态在低温端的体积比不含铁菱镁矿略微增大,在高温端却减小;在所研究的温压范围内,低自旋态的体积始终比高自旋态的体积小。含铁菱镁矿高自旋态的热膨胀系数减小,而自旋转变会导致热膨胀系数增加。考虑高低两种自旋态共存时的热力学性质时,计算结果表明:自旋态共存时的热膨胀系数、速度在自旋共存区间内分别呈现异常增大峰和异常减小峰,并且这些异常变化峰随着温度的升高向高压方向移动。