Melt crystallization of zinc alkali phosphate glasses

Melt crystallization of two zinc alkali phosphate glasses was studied with X-ray diffraction (XRD) experiments to accelerate efforts to melt process these glasses with organic polymers. The inorganic glasses differed markedly in chemical durability (water sensitivity) and crystallization rates. They were studied at room temperature prior to and after melt processing with XRD experiments and in situ at melt temperatures without flow in a novel differential scanning calorimeter/XRD apparatus. The glasses were found to be amorphous at room temperature and semi-crystalline above their glass-transition temperatures. Higher temperatures and shear (mixing) rates increased the crystallization rate of the glasses. The non-durable (water-sensitive) glass was observed to contain significant levels of crystalline matter after melt processing at 400°C. This process-induced crystallization of the glasses must be controlled, possibly during processing and/or glass formulation, otherwise it may lead to formation of unwanted phase-separated defects in the glass. If high levels of the crystalline matter are present during melt processing, they may lead to irreversible plugging of the processing equipment.     

On the boomerang uniformity of permutations of low Carlitz rank

Finding permutation polynomials with low differential and boomerang uniformity is an important topic in S-box designs of many block ciphers. For example, AES chooses the inverse function as its S-box, which is differentially 4-uniform and boomerang 6-uniform. Also there has been considerable research on many non-quadratic permutations which are modifications of the inverse function. In this paper, we give a novel approach which shows that plenty of existing modifications of the inverse function are in fact affine equivalent to permutations of low Carlitz rank, and those modifications cannot be APN. We also present the complete list of permutations of Carlitz rank 3 having the boomerang uniformity six, and give the complete classification of the differential uniformities of permutations of Carlitz rank 3. As an application, we provide all the involutions of Carlitz rank 3 having the boomerang uniformity six.     

New differentially 4-uniform permutations from modifications of the inverse function

Finding permutations with good cryptographic parameters is a good research topic about constructing a secure S-box in substitution-permutation networks. In particular constructing differentially 4-uniform permutations has made considerable progress in recent years. In this paper, we present new differentially 4-uniform permutations from the inverse function composed by disjoint cycles. Our new differentially 4-uniform permutations have high nonlinearity and low differential-linear uniformity. We give the differential spectrum and the extended Walsh spectrum of some of our differentially 4-uniform permutations, and then we can see that they are CCZ-inequivalent to some permutations whose differential spectrum and extended Walsh spectrum are known.     

吡啶在Au电极上吸附的紫外可见反射光谱法研究

电化学调制紫外可见反射光谱技术可用来测定金属电极上吸附物种的取向和吸附物种与金属表面间的相互作用,金属Au与已研究过的Pb、In和Pt^[1～]具有不同形式的能带结构,吸附物种与电极表面间相互作用的电位依赖性可能不同。本文测定了吡啶分子吸附时Au电极的反射差谱,并试图从能带模型角度探讨吡啶分子与Au电极表面原子间的相互作用。     

速差动力学因子分析法测定重稀土混合物

因子分析是解决多变量问题的一种数学方法,在化学中已应用于成分分析,但在速差动力学分析中常的应用未见报道。速差动力学分析中常用的曲线拟合法需先知道混合物的组成,并用纯组分求出动力学参数,而因子分析可不必事先知道组分数及求动力学参数。本文应用因子分析法测定重稀土的二元及三元混合物,得到较好的结果。     

交流示波极谱图测定微分电容法和卤素离子吸附对示波图的影响

本文提出了一种利用交流示波极谱图和微型计算机,快速测定电极溶液界面微分电容的方法,研究了卤素阴离子的特性吸附对示波极谱图的影响,并测定了一些离子的零电荷电位。     

Numerical stability analysis of numerical methods for volterra integral equations with delay argument

The present paper deals with the stability properties of numerical methods for Volterra integral equations with delay argument. We assess the numerical stability of numerical methods with respect to the following test equations (0.1a) $$y\left( t \right) = \psi \left( 0 \right) + \int_0^t {\left( {py\left( s \right) + q\left( {s - \tau } \right)} \right)ds (0 \leqslant t \leqslant X)}$$ (0.1b) $$y\left( t \right) = \psi \left( t \right) \left( {t \in [ - \tau ,0)} \right)$$ where τ is a positive constant, and P and q are complex valued. We investigate the stability properties of reducible quadrature methods and θ-methods in the case of the above test equations     

Kantorovich solution for the problem of bending of a ladder plate

Based on the Kantorovich approximation solution for a rectangular plate in bending, this paper deals with the solutions for the ladder plate with various boundary conditions. The deflection of the plate is expressed in a first-order displacement function w(x,y)=u(x,y)v(y) where the u(x,y) in x direction is the generalized beam function. By making use of the principle of least potential energy, the variable coefficients differential equations for v(y) may be established. By solving is, these differential eugations and making use of the boundary conditions, the accurate solutions of v(y) in y direction may be obtained. Then the displacement function w(x,y) is the solution for the problem of the bending of the ladder plate with a better degree of approximation.     

Approximation of a Two-phase Continuous Casting Stefan Problem

The continuous casting Stefan problem is a mathematical model describing the solidification with convection of a material being cast continuously with a prescribed velocity. We propose a practical piecewise linear finite element scheme motivated by the characteristic finite element method and derive an error estimate for the scheme which is of the same convergence order as that proved for Stefan problem without convection.     

钴(Ⅱ)取代铜锌超氧化物岐化酶金属重组衍生物的电化学和光谱电化学研究

80年代Hill等［"在蛋白质的电化学研究中加人氧化还原促进剂以提高电极反应速率．但最近的研究表明,电极材料的选择、蛋白质的纯度和溶液的离子强度等都影响反应速率和吸附行为［'．我们曾选用悬汞电极在不加促进剂的情况下研究铜锌超氧化物歧化酶Cu。Zn。SOD的电化学性质,并获得较好的结果［'j．本文研究了钻（I）取代铜锌超氧化物歧化酶CO。CO。SOD的氧化还原行为,首先用热解石墨电极对CO。CO。SOD进行循环伏安研究,获得了电极反应为扩散控制的可逆的电化学过程;然后用光谱电化学技术进行论证,由2种方法得到了在CO。CO。…