Global existence and time decay of the non-cutoff Boltzmann equation with hard potential

This paper is concerned with the Cauchy problem on the Boltzmann equation without angular cutoff assumption for hard potential in the whole space. When the initial data is a small perturbation of a global Maxwellian, the global existence of solution to this problem is proved in unweighted Sobolev spaces $H^N\left({\mathbb{R}}_{x,v}^6\right)$ with $N\ge 2$. But if we want to obtain the optimal temporal decay estimates, we need to add the velocity weight function, in this case the global existence and the optimal temporal decay estimate of the Boltzmann equation are all established. Meanwhile, we further gain a more accurate energy estimate, which can guarantee the validity of the assumption in Chen et al. (0000).     

超声波在多糖降解及提取中的应用

本文支综合介绍了超声波在多糖降解和提取中应用的研究进展．着重对超声波在淀粉，壳多糖，细菌多糖的降解和真菌多糖的提取中的应用作了较详细的阐述．     

Effects of Nb2O5 on thermal stability and optical properties of Er3+-doped tellurite glasses

Er³⁺-doped tellurite glasses with molar compositions of xNb₂O₅-(14.7-x)Na₂O--10ZnO--5K₂O--10GeO₂-- 60TeO₂--0.3Er₂O₃ (x=0, 3, 5, 7 and 9) have been investigated for developing 1.5~μm fibre and planar amplifiers. The effects of Nb₂O₅ on the thermal stability and optical properties of Er³⁺-doped tellurite glasses have been discussed. It is noted that the incorporation of Nb₂O₅ (x=5) increases the thermal stability of tellurite glasses significantly. Er³⁺-doped niobium tellurite glasses exhibit a large stimulated emission cross-section (7.2\times 10^-21- 10.7×10^-21~cm² and the gain bandwidth, FWHM×\sigma_e^{\rm peak} (274\times 10^-28 - 480×10^-28~cm³), which are significantly higher than that of silicate and phosphate glasses. In addition, the intensity of upconversion luminescence of the Er³⁺-doped niobium tellurite glasses decreases rapidly with increasing Nb₂O₅ content. As a result, Er³⁺-doped niobium tellurite glasses might be a potential candidate for developing laser or optical amplifier devices.     

NBR/ORGANOMODIFIED BENTONITE INTERCALATED HYBRIDS AND THEIR EFFECTS ON THE TOUGHNESS OF PVC

Hybrids of intercalative nitrile-butadiene rubber/organomodified bentonite (NBR/OMB) were prepared by thelatex intercalation technique. Investigation of their mechanical properties and the microstructore of NBR/OMB showed thatthe organomodified bentonite is an effective toughener for NBR. Transmission electronic microscopy (TEM) and X-rnydiffraction (XRD) tests showed that the NBR macromolecule could be intercalated into the galleries of bentonite.Incorporation of NBR/OMB hybrids as tougheners into poly(vinyl chloride) (PVC) results in a substantial increase in theimpact strength of PVC, but little decrease in its tensile strength and flexural strength, compared to the unmodified PVC.     

Synthesis and photoluminescence properties of 8-hydroxyquinoline derivatives and their metallic complexes

Three new 8-hydroxyquinoline derivatives, i.e. 5-[(4-styryl-benzylidene)-amino]-quinolin-8-ol (1), 5-[(4-bromo-2-fluoro-benzylidene)-amino]-quinoline-8-ol (2) and 2-[2-(9-ethyl-9H-carbazol-2yl)-vinyl]-quinolin-8-ol (3), and their metallic complexes were synthesized and identified by ultraviolet-visible (UV-Vis), ¹H nuclear magnetic resonance (¹H NMR), Fourier transform infrared spectrometer (FTIR), mass spectrometry (MS) spectra and elemental analyses. Their fluorescence properties were studied by photoluminescence, which indicated that the luminescence wavelength of 5-and 2-substitued-8-hydroxyquinoline derivatives shifted to red in comparison with that of 8-hydroxyquinoline. Meanwhile, the fluorescence lifetime of 2-[2-(9-ethyl-9H-carbazol-2yl)-vinyl]-quinolin-8-ol and its zinc complex showed long lifetime in benzene solution. __________ Translated from Chinese Journal of Organic Chemistry, 2007, 27(3): 402–408 [译自: 有机化学]     

γ-Al2O3对NiB合金的催化及表面性能的影响

集），Dalian（大连）：1994，p.262||8LiuWeicheng（刘伟成），YanJingqing（晏荆青），JiangBingnan（姜炳南）．CuihuaXuebao（催化学报），1990，||11（2）：929HuCW，WangWZXuGY，etal．J．Nat．GasChem，1994,（3）：194||     

2-(N'-乙基咔唑-3'-烯基)-8-羟基喹啉的合成及理论研究

设计合成了2-(N'-乙基咔唑-3'-烯基)-8-羟基喹啉. 以UV-Vis, ¹H NMR, FT-IR, 元素分析和MS进行了结构表征, 并测定了产物的光致发光(PL)性质. 运用Gaussian98量子化学程序包, 采用B3LYP密度泛函(DFT)的方法, 在6-31G(d,p)水平上对分子的几何构型进行结构优化; 预测目标产物的振动光谱, 结果表明与实验值相符.     

5,7′-(亚甲胺基)-二-8-羟基喹啉的合成及其理论研究

以4-甲基苯磺酸作催化剂、用三乙胺调节pH值约为9的条件下, 由5-甲酰基-8-羟基喹啉和5-氨基-8-羟基喹啉合成了新的5,7′-(亚甲胺基)-二-8-羟基喹啉, 利用IR, UV, ¹H NMR, MS确认了分子结构, 比较研究了其光致发光特性, 运用Gaussian 98量子化学程序包, 采用B3LYP密度泛函(DFT)的方法, 在6-31G(d,p)水平上对分子的几何构型进行结构优化; 并对目标化合物的稳定结构通过计算预测其振动光谱, 计算结果与实验值基本相符.     

Ternary interpenetrating networks of polyurethane-poly(methyl methacrylate)-silica: Preparation by the sol–gel process and characterization of films

Novel organic/inorganic interpenetrating networks composed of polyurethane (PU), poly(methyl methacrylate) (PMMA) and silica generated from tetraethoxysilane (TEOS), were prepared by in situ bulk polymerization. Optically transparent films were successfully synthesized using 3-(trimethoxysilyl)propyl methacrylate (TMSPM) and isocyanatopropyl triethoxysilane (IPTES) as dual coupling agents. An experimental protocol was established to minimize undesirable side-reactions. According to infrared spectroscopic analysis and thermogravimetric studies of the hybrid materials, the degree of silica condensation was unfavorably affected by the presence of the organic components. Consequently, storage modulus (E′) at 25 °C, and hardness of the films decreased with increasing silica content.