Isolation and Structure Elucidation of Nortriterpenoids from Schisandra rubriflora

Seven new highly oxygenated nortriterpenoids, rubriflorins D–J ( 1 – 7 ), were isolated from the leaves and stems of Schisandra rubriflora, and their structures were elucidated on the basis of extensive analysis of spectroscopic data. These new compounds feature the opening of ring A compared with related known nortriterpenoids isolated from the genus Schisandra and showed weak activity against HIV‐1.     

Low-energy ion-assisted control of interfacial structures in metallic multilayers

A molecular dynamics method has been used to simulate the argon ion-assisted deposition of Cu/Co/Cu multilayers and to explore ion beam assistance strategies that can be used during or after the growth of each layer to control interfacial structures. A low-argon ion energy of 5–10 eV was found to minimize a combination of interfacial roughness and interlayer mixing (alloying) during the ion-assisted deposition of multilayers. However, complete flattening with simultaneous ion assistance could not be achieved without some mixing between the layers when a constant ion energy approach was used. It was found that multilayers with lower interfacial roughness and intermixing could be grown either by modulating the ion energy during the growth of each metal layer or by utilizing ion assistance only after the completion of each layers deposition. In these latter approaches, relatively high-energy ions could be used since the interface is buried and less susceptible to intermixing. The interlayer mixing dependence upon the thickness of the over layer has been determined as a function of ion energy.     

线性系统和迭加原理

以系统的观点给出电路分析中的一个重要定理——迭加定理，并对迭加定理的证明。迭加定理与线性系统的关系．迭加定理的齐次性和可加性，作了较详细的论证。     

铽－甲基吲哚乙酰丙酮三元配合物发光过程研究

测定和分析了ＲＥ．Ｌ１．Ｌ２（ＲＥ＝Ｔｂ（Ⅲ）、Ｇｄ（Ⅲ），Ｌ１＝３Ｍ（３甲基吲哚－１－乙酰基丙酮），Ｌ２＝ＴＰＰＯ、Ｐｈｅｎ、Ｄｉｐｙ）三元配合物的荧光光谱、磷光光谱、磷光寿命及变温荧光光谱等．讨论了Ｔｂ（Ⅲ）与配体之间的能级匹配和Ｌ１与Ｌ２的三重态之间传能的问题，说明了影响这些三元配合物荧光效率的主要因素及其发光过程．     

Synthesis of 5‐Radioiodoarabinosyl Uridine Analog for Probing the HSV‐1 Thymidine Kinase Gene

Tumor cells transduced with herpes simplex virus thymidine kinase gene have been intensively applied to the field of positron emission tomography via imaging of its substrate. As a pilot synthesis approach, a facile preparation of 5‐[¹²⁵I] iodoarabinosyl uridine starting from commercially available uridine is reported herein.     

The growth of Pd thin films on a 6H-SiC(0 0 0 1) substrate

Pd thin films, grown on Si-rich 6H-SiC(0 0 0 1) substrates, were studied by atomic force microscopy, electron diffraction and high-resolution transmission electron microscopy. It is concluded that the growth is successful only when all the growth process takes place at room temperature. Under these conditions a very good epitaxial growth of Pd is achieved, despite the large misfit (about 8.6%) between Pd and the substrate and the existence of a semi-amorphous layer between the thin film and the substrate. A large number of twins appear in these films.     

Synthesis and characterization of poly(higher‐α‐olefin)s with a nickel(α‐diimine)/methylaluminoxane catalyst system: Effect of chain running on the polymer properties

Homopolymerization of octadecene‐1 at different reaction conditions has been studied. Significant chain running can be seen at higher polymerization temperatures. Interestingly, insertion of octadecene‐1 into a sterically hindered nickel‐cation/carbon (secondary) bond is observed. The microstructure of the polymer was established using NMR spectroscopy. The effects of chain running on polymer melting, crystallization behavior, and dynamic mechanical thermal properties were studied using DSC and DMTA. The extent of chain running (i.e., 2,ω‐, 1,ω‐enchainments) decreases with an increase in the carbon number of α‐olefins. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 191–210, 2007     

左截断右删失下核密度估计的L1距离的界

本文在左截断右删失数据下获得了概论密度的核估计的L1距离的一个上界．     

Theoretical study of anion carriers based on trifluoroacetophenone

Model calculations on anion carrier ligands related to trifluoroacetophenone were carried out using the semiempirical AM 1 method in order to investigate the factors involved in such anion-ligand complexation. The reaction of halogen derivatives of acetophenone with various nucleophiles such as water, carbonic acid, and bicarbonate anion was studied. By this means, the effect of various structural changes, such as variation of the ring substituents and variation of the degree and type of halogen atom substitution, could be determined. It is shown that in terms of relative stability, fluorine derivatives are preferable to chlorine derivatives for the binding of water and carbonic acid. Monosubstitution of a methoxy group in the ortho position of the trifluoroacetophenone ring also brought about stability in the case of the hydration reaction. An electron-withdrawing ester group in the para position on the trifluoroacetophenone ring brings about stabilization also.