The Inclusion Interval of Basic Coneigenvalues of a Matrix

In this paper,a compound-type inclusion interval of basic coneigenvalues of(com- plex)matrix is obtained.The corresponding boundary theorem and isolating theorem are given.     

CONSTRUCTION OF SOLUTIONS TO M-D RIEMANN PROBLEMS FOR A2×2 QUASILINEAR HYPERBOLIC SYSTEM

ＣＯＮＳＴＲＵＣＴＩＯＮＯＦＳＯＬＵＴＩＯＮＳＴＯＭ－ＤＲＩＥＭＡＮＮＰＲＯＢＬＥＭＳＦＯＲＡ２×２ＱＵＡＳＩＬＩＮＥＡＲＨＹＰＥＲＢＯＬＩＣＳＹＳＴＥＭＣＨＥＮＳＨＵＸＩＮＧＭａｎｕｓｃｒｉｐｔｒｅｃｅｉｖｅｄＤｅｃｅｍｂｅｒ２６，１９９４．...     

Syntheses, Structures and Coordination Behavior of Central Hydroxyl Group Containing Polydentate Ligands

Proteins containing dinuclear Cu (II), Zn (II) centers play paramount roles in biology1. As mimetic of metal-dependent esterase, dinuclear Cu (II) and Zn (II) complexes have received a great deal of attentions2~6. They are of interest in the field of biomimetic chemistry to provide an improved understanding of the function of the biological sites and as potential catalysts for substrate oxidations. Schiff base type polydentate ligands which contain centeral hydroxyl group have been wid…     

K-La-Ni/Si-2催化低碳烷烃与二氧化碳重整制合成气(英文)

Ｎｉ／Ｓｉ２催化剂具有较好的低碳烷烃与二氧化碳重整制合成气的反应性能，添加Ｌａ２Ｏ３助剂和Ｋ２Ｏ助剂可提高催化剂活性和合成气收率，从而进一步改善催化剂的低碳烷烃与ＣＯ２重整制合成气的反应性能，研制的ＫＬａＮｉ／Ｓｉ２催化剂，用于天然气与ＣＯ２重整反应制合成气可达９７％的低碳烷烃转化率和９５％以上的合成气收率。     

Polystyrene-supported Benzyl Selenide: An Efficient Reagent for Highly Stereocontrolled Synthesis of Substituted Olefins

Solid-phase methodology has been rapidly and extensively applied to the preparation of small organic molecules recently1. It might be argued that selenoxide syn-elimination provided the principal impetus for the development of organoselenium chemistry. In addition, the required selenoxides are readily available from the oxidation of the corresponding selenides, which in turn can be prepared by the reaction of selenium-stabilized carbanions with various electrophilic substrates2. However, or…     

Thermal decomposition kinetics of titanium hydride and Al alloy melt foaming process

Metal foams, now one of research foci, are a newclass of materials with low densities and novel physi-cal, mechanical, thermal, electrical and acoustic prop-erties[1—8]. Demands from high-tech make Al alloyfoam, which has much higher specific strength than ofpure Al foam, the new development focus[9—11]. Melt foaming process is one of the approaches tofabricate Al foam and Al alloy foam and their porestructure (pore diameter and porosity) has close rela-tionship with the thermal decompo…     

Structural Features of a Polysaccharide from Centella asiatica

Centella asiatica has been used as remedy for sodation, stabilization and against lepra, anabrosis1 in the oriental countries. The low-molecular-weight constituents in Centella asiatica have been investigated1. However, no polysaccharides have been reported. 1BI was the first polysaccharide isolated from C. asiatica, which had immunostimulating activity in vitro. In present study, we report the structural features of 1BI. Experimental Extraction, isolation and purification Dried C.…     

O2在MgO(001)完整和缺陷表面上的吸附

在密度泛函理论的框架下， 采用嵌入点电荷簇模型研究了O2在MgO(001)完整和缺陷表面上的吸附.用电荷自洽的方法确定了点电荷的值.计算结果表明， O2倾向吸附在低配位的角Mg2＋端.并且发现， 当O2为平躺吸附时，键长有较大的拉伸，将有利于O2的解离.同时，分别计算了使用裸簇和嵌入表观±2.0 e点电荷簇模型时的吸附能，并与采用电荷自洽方法的计算值进行了比较.结果表明，电荷自洽方法更能有效反映簇周围的环境，得到的计算结果能够较好地与实验值吻合.最后，分别计算了不同吸附情况下O2的振动频率.     

甲醇在Au(111)表面吸附的密度泛函研究

 采用基于第一性原理的密度泛函理论和周期平板模型相结合的方法,对CH3OH分子在Au(111)表面top, fcc, hcp和bridge位的吸附模型进行了构型优化、能量计算以及Mulliken布居分析,结果表明top位是较有利的吸附位. 吸附的CH3OH解离产生甲氧基CH3O和H, 对它们在Au(111)面的吸附进行的计算表明, bridge和fcc位分别是二者的最佳吸附位. 对过渡态的计算给出了CH3OH在Au表面解离吸附的可能机理: 首先发生 O-H 键的断裂,继而生成甲氧基中间体.     

Studies on the Total Synthesis of Hainanolide (VII) - Analysis of the Relative Stereochemistry of key Intermediate 2

The natural product, hainanolide 1, also under the name harringtonolide2 demonstrated antitumor and antiviral activities in preliminary test. Its structure was determined by X-ray diffraction. The total synthesis of 1 was reported recently by Mander3. A different scheme of its synthesis has been studied in our laboratory4. Here the determination of the stereochemical structure of the key intermediate 2 in the synthesis was reported. HMBC and HMQC spectra identified the skeleton and H,…