微波消解-氢化物发生-原子荧光光谱法测定7种中草药中砷

利用原子荧光光谱法测定7种驱虫类中草药中的砷.实验采用微波消解样品,以盐酸为测定介质,硫脲-抗坏血酸为预还原剂,硼氢化钾为氢化剂,用氢化物发生-原子荧光光谱法测定砷含量.砷含量在10-100ng/mL浓度范围内线性关系好(r2=0.9924).回收率为93.83%-110.94%之间.方法简便、快速、灵敏、准确,可用于中草药中砷的测定.     

原子吸收光谱法测定铅蓄电池板栅中锡、钙和铝

通过先加酒石酸、硝酸溶解样品,用氧化镧、EDTA联合掩蔽铝来测定钙,盐酸沉淀铅后测锡、铝的试验,采用火焰原子吸收光谱法测定锡、钙和铝.     

High-throughput experimentation in synthetic polymer chemistry: From RAFT and anionic polymerizations to process development

The application of combinatorial and high-throughput approaches in polymer research is described. An overview of the utilized synthesis robots is given, including different parallel synthesizers and a process development robot. In addition, the application of the parallel synthesis robots to reversible addition fragmentation termination (RAFT) radical polymerizations and ionic copolymerizations is overviewed. Moreover, first results concerning the process development of semi-batch free radical polymerizations are described.     

具Hardy-Sobolev临界指数的奇异椭圆方程多解的存在性

运用变分方法研究了下面问题-Δpu=μupx(s)s-2u f(x,u),x∈Ω,u=0,x∈Ω,多重解的存在性,其中Ω是一个具有光滑边界的有界区域.     

Study on crystalline properties of Er-Si-O compounds in relation to Er-related 1.54 μm photoluminescence and electrical properties

Er-Si-O crystalline compounds, which exhibit superlattice structures and sharp and strong Er-related 1.54 μm photoluminescence (PL) spectra at room temperature have been formed by self-assembling growth mechanism. Oxidation of the starting materials which have Si and Er at an atomic ratio of 2:1 are prepared and then oxidation and succeeding high-temperature annealing in Ar above 1250 °C cause a self-assembled superlattice-structured Er-Si-O crystalline compounds. The control of the ratio of Si and Er, as well as the following oxidation and annealing processes, is found to be sensitive to the crystalline properties, PL spectra and electrical properties. In this study, Er-Si-O crystalline thin films are formed on Si substrates by sol-gel and MOMBE methods, and their crystalline properties such as crystalline orientation and concentration ratio of Er, Si and O are investigated. Crystalline Er-Si-O films of high orientation are successfully grown on Si(1 0 0) and its inclined surface. The PL and excitation spectra, fluorescence decay and the electrical properties are found to be strongly related to the crystalline properties. Excess O causes a broader 1.54 μm PL spectra, slower fluorescence decay, lower carrier-mediated excitation and higher resistivity. A precise control of O is found to be necessary to grow superlattice-structured Er-Si-O compounds, which are semiconducting and are excitable via carrier-mediated excitation mechanism.     

On the Boltzmann Equation for Fermi–Dirac Particles with Very Soft Potentials: Averaging Compactness of Weak Solutions

The paper considers macroscopic behavior of a Fermi–Dirac particle system. We prove the L ¹-compactness of velocity averages of weak solutions of the Boltzmann equation for Fermi–Dirac particles in a periodic box with the collision kernel b(cos θ)|ρ−ρ _*|^γ, which corresponds to very soft potentials: −5 < γ ≤ −3 with a weak angular cutoff: ∫₀ ^π b(cos θ)sin ³θ dθ < ∞. Our proof for the averaging compactness is based on the entropy inequality, Hausdorff–Young inequality, the L ^∞-bounds of the solutions, and a specific property of the value-range of the exponent γ. Once such an averaging compactness is proven, the proof of the existence of weak solutions will be relatively easy.     

Necessary Conditions for Differentiability of Distance Functions

Necessary conditions for the Gâteaux differentiability of the distance function to a set are considered. A series of characterizing results is obtained.     

On an Application of Newton's Method to Nonlinear Operators with w-Conditioned Second Derivative

We present a new approach to study the convergence of Newton's method in Banach spaces, which relax the conditions appearing in the usual studies. The approach is based on the bound required for the second derivative of the operator involved. An application to a nonlinear integral equation is presented.     

凸域内单叶函数的导数

设函数f（w）为凸区域D内的单叶解析函数,对于2≤n≤8和所有w∈D,本文得到估计式|f（n）（w）/f＇（w）|的精确上界.这个结果推广了一些已知的结论.     

〈I〉型三角剖分下非张量积连续小波基的构造

多维非张量积小波是近年小波研究领域中的热点问题之一 ,它们与多维张量积小波相比具有更多的优势 .关于高维张量积、非张量积小波 ,目前已有一些很好的工作 (见文[2 ] [3 ] [4 ] ) ,但关于样条小波 ,还有许多问题有待于研究 .本文针对〈I〉型三角剖分下的二维线性元空间 ,讨论其具有紧支集和对称性的半正交样条小波基 .给定 x1 x2 平面上的〈I〉型三角剖分 (图 1 ( a)所示 ) ,记 j=( j1 ,j2 ) ,| j| =j1 + j2 ,πm= { 0≤ |j|≤ mCj1j2 xj11 xj22 ,Cj1,j2 是任意实数 }为次数不超过 m的代数多项式全体 .引入剖分尺度为 1的线性元空间 V0…