基于可减的实半环与实素理想

半环R被称为实半环,若对于任意的n∈N,方程x1^2＋…＋xn^2=0在R中只有零解：x1=…=xn=0.为了刻画实半环,引入了实理想和极小素理想的概念,利用同余的方法,得到了可减半环类中实半环的结构定理.     

Synthesis and Characterization of a Novel Binuclear Cobalt(II) Complex with Discrete Water Clusters (H2O)8

A new octameric water cluster was observed in the complex Co₂(dptc)(bipy)₂(H₂O)₆ · 4H₂O ( 1 ) (H₄dptc = diphenyl‐3,3′,4,4′‐tetracarboxylic acid; bipy = 2,2′‐bipyridine), which was characterized by single‐crystal X‐ray diffraction, elemental analysis and IR spectroscopy. The centrosymmetric octamer consists of a water hexamer in the chair form and two water molecules and brings to light a novel mode of the cooperative association of water molecules. Those complex units are connected into a 2D infinite layer framework through hydrogen bonding. Consequently, the 2D layers are further aggregated by hydrogen bonding with octameric subunits and π ··· π stacking interactions to form a 3D supramolecular architecture.     

Electrochemical quartz crystal microbalance study on Au-supported Pt adlayers for electrocatalytic oxidation of methanol in alkaline solution

Underpotential deposition (UPD) of Cu on an Au electrode followed by redox replacement reaction (RRR) of Cu_UPD with a Pt source (H₂PtCl₆ or K₂PtCl₄) yielded Au-supported Pt adlayers (for short, Pt(CuUPD-Pt⁴⁺)n/Au for H₂PtCl₆, or Pt(CuUPD-Pt²⁺)n/Au for K₂PtCl₄, where n denotes the number of UPD-redox replacement cycles). The electrochemical quartz crystal microbalance (EQCM) technique was used for the first time to quantitatively study the fabricated electrodes and estimate their mass-normalized specific electrocatalytic activity (SECA) for methanol oxidation in alkaline solution. In comparison with Pt(CuUPD-Pt²⁺)n/Au, Pt(CuUPD-Pt⁴⁺)n/Au exhibited a higher electrocatalytic activity, and the maximum SECA was obtained to be as high as 35.7 mA μg^?1 at Pt(CuUPD-Pt⁴⁺)3/Au. The layer-by-layer architecture of Pt atoms on Au is briefly discussed based on the EQCM-revealed redox replacement efficiency, and the calculated distribution percentages of bare Au sites agree with the experimental results deduced from the charge under the AuO _x -reduction peaks. The EQCM is highly recommended as an efficient technique to quantitatively examine various electrode-supported catalyst adlayers, and the highly efficient catalyst adlayers of noble metals are promising in electrocatalysis relevant to biological, energy and environmental sciences and technologies.     

导电聚合物热电材料研究进展

随着煤、石油、天然气等不可再生化石燃料的减少和世界能源需求的不断增加,近年来导电聚合物热电材料的研究逐渐引起人们的关注。本文介绍了近年来导电聚合物热电材料的研究进展,简要分析聚合物热电材料目前存在的主要问题,并提出提高聚合物热电材料性能的初步策略。     

Specific Proteins in the Indirect Somatic Embryogenesis of Freesia

Using the young inflorescence segments of Freesia refracta as explants, indirect somatic embryogenesis of somatic cells was induced in a N6 medium supplemented with some exogenous hormones. SDS-polyacrylamide gel electrophoresis（SDS-PAGE） was used for the analysis of soluble proteins produced during the somatic embryogenesis of this plant. There are six polypeptides, which might play some roles in the process of somatic embryo development. Tltree polypeptides（45, 53 and 55 kD） were detected in the stages of embryogenic callus, globular embryoid, and embryoid with coleoptiles, except the embryoid with leaf. One polypeptide（ 83 kD） was specific for the stages of embryoid with eoleoptiles and embryoid with leaf. One polypeptide（37 kD） was detected in the first two stages, namely, embryogenic callus and globular embryoid. One polypeptide（35 kD） was regularly synthesized in each stage, from embryogenic callus to embryoid with leaf.     

图$P_m\times P_n, P_m\times C_n$ 和C_m\times C_n$}的邻点可区别全色数的注记

设 $G$ 是一个简单图. 设$f$是从$V(G) \cup E(G)$到 $\{1, 2,\ldots, k\}$的一个映射.对任意的 $v\in V(G)$, 设$C_f(v)=\{f(v)\}\cup \{f (vw)|w\in V(G),vw\in E(G)\}$ . 如果 $f$ 是一个 $k$-正常全染色, 且对 $u, v\in V(G),uv\in E(G)$, 有 $C_f(u)\neq C_f(v)$, 那么称 $f$ 为$k$-邻点可区别全染色 (简记为$k$-$AVDTC$). 设     

L^2（R^n） Boundedness for a Class of Multilinear Singular Integral Operators

The L^2(R^n) boundedness for the multilinear singular integral operators defined by TAf(x)=∫R^nΩ（x-y）/|x-y|^n 1(A(x)-A(y)-△↓A(y)(x-y))f(y)dy is considered,where Ω is homogeneous of degree zero,integrable on the unit sphere and has vanishing moment of order one,A has derivatives of order one in BMO(R^n） boundedness for the multilinear operator TA is given.     

Study on Electrochemical Copolymerization of Aniline and 3-Methylthiophene in HMIMBF4 Ionic Liquid and Its Properties

Electrochemical polymerization of aniline and 3-methylthiophene has been accomplished in 1-methylimidazium tetrafluoroborate （HMIMBF4） ionic liquid. Homopolymer and copolymers of aniline and 3-methylthiophene were obtained successfully. The copolymer was studied by cyclic voltammetry and electrochemical impedance spectroscopy. The formation of copolymer has been confirmed by FT-IR and UV spectra. The atomic force microscope （AFM） was used for microstructural analysis. Both the homopolymer and the copolymer had the catalytic activity for the hydroquinone.     

An efficient total synthesis of (+/-)-lycoramine

[reaction: see text] A short and unique approach to (+/-)-lycoramine as one of the galanthamine-type alkaloids has been efficiently developed. The alternative advantage lies in that three stereocenters, including a crucial quaternary carbon center, were constructed with high diasteroselectivity via a key one-step NBS-mediated semipinacol rearrangement of the allylic alcohol.     

Orientations of Rare—earth—containing Heteropolyoxometalates with Different Sizes in the Interlayer of Synthetic Multibilayer Films

Three rare-earth-containing heteropolyoxometalates with different sizes, Na9[Eu(W5O18)2],K13[Eu(SiW11O39)2], and K17[Eu(P2W17O61)2], have been incorporated by self-assembly into the interlayer of synthetic multibilayer films of dimethyldioctadecylammonium chloride and exhibited different orientations.