L-群P(G)格的一些性质

本文讨论了L-群格C(G),U,P(G)之间的关系,并用P(G)格的理想,刻画了L-群的Z-子群。     

螯合剂与牛血清白蛋白竞争镉作用的研究

研究了十一种螯合剂使结合在牛血清白蛋白(BSA)上的镉活动化的能力。由凝胶色谱法测得的F值将螯合剂活动镉的能力排成以下顺序:DTP>EDTA>EGTA>NTA>TRIEN>;PEN>CYS>HIS>SA氨羧络合剂型配体能有效地与BSA竞争,而且它们的lgF与lgK_CdL间有一线性关系。     

关于十二硼烷二钠盐的合成

硼簇化合物的合成路线长，原料昂贵和产率低，使硼簇物化学的基础研究和开发应用受到了很大的限制．８０年代前苏联科学家对合成Ｂ１２Ｈ２－１２方法做了改进，用非挥发性的（Ｃ２Ｈ５）３Ｎ·ＢＨ３代替剧毒硼烷，产率高达９３．５％～９５％［１］，但需要特殊实验装置...     

一类无穷区间的倒向随机微分方程及其应用

本文讨论了一类基于无穷区间的倒向随机微分方程解的存在唯一性及其性质. 由方程解定义一类非线性g-期望, 并讨论其在经济金融中的应用.     

Synthesis and optical properties of tetragonal KTa0.6Nb0.4O3 nanoparticles

Tetragonal phase KTa_0.6Nb_0.4O₃ (KTN) nanoparticles have been prepared by hydrothermal method. The obtained particles were characterized by X-ray powder diffraction, transmission electron microscopy, energy dispersive X-ray spectroscopy and UV-vis absorption spectrum techniques. A systematic change in crystal structure from cubic to tetragonal is observed with the increase of reaction temperature and KOH concentration. Room temperature UV-vis absorption spectrums of KTN particles show that the band gap changes from 3.24 to 3.34 eV with grain size diminished, which reveals the existence of blue-shift phenomenon of absorption bands.     

Coherent enhancement of broadband frequency up-conversion in BBO crystal by shaping femtosecond laser pulses

An optimal feedback control of broadband frequency up-conversion in BBO crystal is experimentally demonstrated by shaping femtosecond laser pulses based on genetic algorithm, and the frequency up-conversion efficiency can be enhanced by ∼16%. SPIDER results show that the optimal laser pulses have shorter pulse-width with the little negative chirp than the original pulse with the little positive chirp. By modulating the fundamental spectral phase with periodic square distribution on SLM-256, the frequency up-conversion can be effectively controlled by the factor of about 17%. The experimental results indicate that the broadband frequency up-conversion efficiency is related to both of second harmonic generation (SHG) and sum frequency generation (SFG), where the former depends on the fundamental pulse intensity, and the latter depends on not only the fundamental pulse intensity but also the fundamental pulse spectral phase.     

Orbital correlations in the pseudocubic O and rhombohedral R phases of LaMnO3

The local and intermediate structure of stoichiometric LaMnO3 has been studied in the pseudocubic and rhombohedral phases at high temperatures (300-1150 K). Neutron powder diffraction data were collected and a combined Rietveld and high real space resolution atomic pair distribution function analysis was carried out. The nature of the Jahn-Teller (JT) transition around 750 K is confirmed to be orbital order to disorder. In the high-temperature orthorhombic (O) and rhombohedral (R) phases, the MnO6 octahedra are still fully distorted locally. More importantly, the intermediate structure suggests the presence of local ordered clusters of diameter approximately 16 A ( approximately 4 MnO6 octahedra) implying strong nearest-neighbor JT antiferrodistortive coupling. These clusters persist well above the JT transition temperature even into the high-temperature R phase.     

Application of Dispersive Liquid�CLiquid Microextraction for the Analysis of Six Fungicides in Fruit Samples by GC�CECD

A novel approach for the determination of six fungicides (triadimefon, procymidone, hexaconazole, myclobutanil, diniconazole and iprodione) in fruit samples is presented. Analytes were extracted using the dispersive liquid?Cliquid microextraction technique and determined by GC?CECD. Parameters affecting the dispersive liquid?Cliquid microextraction performance, such as the kind and volume of extraction and dispersive solvents, extraction time and salt concentration, were studied and optimized. Under the optimum extraction conditions, the linearities of the method were obtained in the range of 0.5?C20.0 ??g kg^?1 for triadimefon, hexaconazole, diniconazole and procymidone, and 1.0?C40.0 ??g kg^?1 for myclobutanil and iprodione, with the correlation coefficients ranging from 0.9902 to 0.9995. The enrichment factors ranged from 685 to 820 and the extraction recoveries ranged from 81.3 to 98.4%. The relative standard deviations varied from 3.1 to 7.8%. The limits of detection of the method were in the range of 0.02?C0.12 ??g kg^?1. Results showed that the method we proposed can meet the requirements for the determination of target fungicides in fruit samples. Several compounds considered in this study were found in fruit samples.     

A Note on Gaussian BV Function and Its Heat Semigroup Characterization

In this note, we investigate the properties of Gaussian BV functions and give a heat semigroup characterization of BV functions in Gauss space. In particular, the latter is the nontrivial generalization of classical De Giorgi's heat kernel characterization of function of bounded variation on Euclidean space to the case of Gauss space.     

Promoting performance and CO tolerance of Pt nanocatalyst for direct methanol fuel cells by supporting on high-surface-area silicon carbide

SiC-supported Pt nanocatalyst was prepared by electrodeposition of Pt nanoparticles on the surface of high-surface-area SiC, which was fabricated by a versatile carbothermal reduction method. Characterization studies show that such synthesis protocol leads to well distribution of Pt nanoparticles, with a mean particle size of 2.9 nm on the support. This catalyst has been electrochemically characterized toward methanol oxidation, which exhibits higher catalytic activity, durability, and electrochemical active surface area than the electrodeposited Pt on multiwalled carbon nanotubes (MWCNTs). Further investigation reveals that the SiC-supported Pt also shows superior CO tolerance to Pt/MWCNTs. These results suggest that high-surface-area SiC could be a promising supporting material for constructing high-performance methanol oxidation electrocatalysts.