A sampling theorem with error estimation for S-transform

S-transform (ST) is an extension of wavelet transform (WT) and short-time Fourier transform (STFT). The ST is depended on a scalable and moving Gaussian window. It overcomes the low-resolution factor of STFT and tackles with a lack of phase in WT. The ST is a useful tool for signal processing and analysis. In this paper, the multiresolution analysis (MRA) related with ST is introduced and after that a sampling theorem associated with ST is proposed which is based on multiresolution subspace. Additionally, truncation and aliasing error generated due to the sampling process, are also derived. The theoretical determinations are exhibited and validated using simulation results.     

Synthesis and characterization of secondary‐amine‐functional microparticles

Secondary‐amine‐functional microparticles were prepared in the range of 50–250 μm through the suspension polymerization of styrene, divinylbenzene (DVB), and 2‐(tert‐butylamino)ethyl methacrylate (tBAEMA). This study focused on the effects of the DVB, tBAEMA, initiator, and stabilizer concentrations and shaking rate on the experimental amine content, swelling ratio, average particle size, and particle size distribution. The suspension polymerization experiments were carried out in two different systems. In the first system, an organic phase, including the monomers and initiator, was dispersed in an aqueous medium in the presence of Al₂(SO₄)₃. Al₂(SO₄)₃, in the presence of an amine monomer (pH ～ 10), formed colloidal Al(OH)₃, which built a nonsticky layer on the surface of the polymerizing droplets that prevented them from coalescing and aggregating. Individual and spherical particles within the range of 50–200 μm were obtained by this polymerization method. The second method was similar to the first polymerization protocol, except that a certain amount of sodium dodecyl sulfate was added as a costabilizer in the presence of Al₂(SO₄)₃. In these experiments, individual and spherical particles were obtained within the range of 130–250 μm. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem: 3708–3719, 2004     

A simple model of growth and product formation in cell suspensions ofCatharanthus roseus G. Don

This paper describes the application of a simple log-linear model to suspension cultures of the species Catharanthus roseus G. Don. Data obtained experimentally have been interpolated by a cubic spline to give data points of regular time period. A logarithmic transformation has been applied and a linear model fitted to these transformed variables. The results show that there is a reasonable fit to the experimental data cited. Using this model a one-step ahead prediction is made for a series of untried experimental variables, and the results generated are compared with the experimental data subsequently obtained.     

A model for line transect sampling clustered populations

A model is presented for the estimation of population density using line-transect methods on clustered individuals. The model assumes independent sighting of clusters but does not require all individuals in a cluster to be sighted.     

基于Gibbs抽样的随机前沿面半参数模型的估计

本文对文献[1]提出的随机前沿面半参数模型的参数估计作了进一步研究,利用基于Gibbs抽样的技术,成功构造出了随机前沿面半参数模型的参数估计,并给出了生产技术有效性测算的方法及其证明,提高了随机前沿面半参数模型的应用价值.     

节流脉冲-火焰原子吸收法测定人发中的微量元素

本文提出了节流脉冲进样火焰原子吸收测定同一样品溶液中多种微量元素的新方法,该方法样品用量少、精密度好、简便实用,可用于人发中多种微量元素的常规检测。     

The flow of a model suspension fluid past a sphere

The paper is concerned with the flow of a dilute suspension of monosized spheroids past a sphere placed at the centerline of a cylindrical tube. The suspension is modeled by the transversely isotropic fluid model and the numerical solution is obtained by a time-dependent boundary element method. No steady-state solution to the problem was found. However, the amplitude of the long-time oscillations in the drag force on the sphere is only about 1% of its mean value at a solid volume concentration of 0.01 and an aspect ratio of 10 for the spheroids. The initial orientation of the microstructure has a small effect on the drag force: it can give rise to a ±1 % variation in the drag force at large time.     

一种可供选择的随机化调查方法

本文提出了一种新的随机化调查方法,Warner(1965)和Horvitz,Simmons(1967)随机化回答方法是本文方法的特殊情形.这一方法比Warner(1965)方法和Mangat(1990)方法更有效. 当考虑存在不真实回答时,在一定的条件下并且不损失对个体保护度和不增加调查成本的前提下,提出的方法优于Simmons(1967)方法和Sarjinder Singh(2000)方法.对简单随机不放回抽样,在总体非敏感属性个体比例未知的情况下,给出了两个子样本容量的最优配置.     

位置刻度分布族中参数的两步置信区间

寻找一些分布中的参数的具有预先给定宽度和预先给定覆盖概率的置信区间是令人感兴趣的，对于位置刻度分布族中位置参数和刻度参数，这种类型的置信区间的存在性问题已在文献中被解决，本文利用两步抽样，具体地构造出这样的固定宽度置信区间，此外，对于Cauchy分布，第一阶段的最优抽样量和一些统计量的分位点也被计算出，所得到的结果具有应用价值。     

砷化镓高速集成电路内部电信号的光探针直接取样

本文介绍了电光取样技术原理报道了砷化镓高速集成电路内部电信号在片直接电光取样测量系统,它的时间分辨率优于20ps,空间分辨率优于3μm.通过对砷化镓共面波导的测量证实该系统可以对砷化镓高速集成电路内部电信号进行在片直接电光取样测量。