Radial basis function neural networks in non-destructive determination of compound aspirin tablets on NIR spectroscopy

The application of the second most popular artificial neural networks (ANNs), namely, the radial basis function (RBF) networks, has been developed for quantitative analysis of drugs during the last decade. In this paper, the two components (aspirin and phenacetin) were simultaneously determined in compound aspirin tablets by using near-infrared (NIR) spectroscopy and RBF networks. The total database was randomly divided into a training set (50) and a testing set (17). Different preprocessing methods (standard normal variate (SNV), multiplicative scatter correction (MSC), first-derivative and second-derivative) were applied to two sets of NIR spectra of compound aspirin tablets with different concentrations of two active components and compared each other. After that, the performance of RBF learning algorithm adopted the nearest neighbor clustering algorithm (NNCA) and the criterion for selection used a cross-validation technique. Results show that using RBF networks to quantificationally analyze tablets is reliable, and the best RBF model was obtained by first-derivative spectra.     

Study of lower emittance dedicated synchrotron radiation mode for the BEPCⅡ

In this paper,a dedicated synchrotron radiation （SR） mode for the BEPCⅡ with an emittance of 85 nm has been designed,including the linear lattice,chromaticity correction and dynamic aperture optimization.The emittance of the new mode is about 60% of the previous mode used for routine operation of the BEPCⅡ .The effect of wigglers on the linear lattice was compensated and the total dynamic aperture including the wigglers’ nonlinear effect was estimated.The preliminary commissioning at the end of 2008 and the formal operation with the new mode confirmed its merits.     

Stress evolution and lattice distortion induced by thickness variation and lattice misfit in La0.67Sr0.33MnO3−δ films

La_0.67Sr_0.33MnO_3?δ thin films with different thicknesses are prepared in order to investigate the structural variation induced by film thickness and lattice misfit. The X-ray diffraction results show the in-built stress evolution from a full strained thin layer (～10 nm) to a completely relaxed thick layer (～150 nm), which can be well explained by the Poisson effect. Raman spectroscopy measurements reveal the complicated correlation between the Jahn–Teller (JT) distortion and film thickness. Important octahedron modes reflecting JT distortion are completely caused by the relaxed layer. It is observed that broad JT bands are formed in the films with large thickness of the relaxed layer and the residual stress in the layer leads to an obvious blue shift. In contrast, for films with the thin relaxed layer, JT modes are present as a sharper structure and move to low frequency, indicating towards a much better oxygen stoichiometry.     

求一阶数值微分的L-广义解方法cTSVD

<正>1引言数值微分也就是给定一个函数在一个区间或某些离散点上的扰动数据来求函数的导数,它产生于很多实际问题当中,比如,图象处理中的边界识别问题;Abel积分方程的求解问题;化学中波谱的波峰识别问题.以及一些数学物理反问题当中.数值微     

Thermal properties of bi nanowire arrays with different orientations and diameters

The thermal properties of single-crystalline Bi nanowire arrays with different orientations and diameters were studied by differential scanning calorimeter and in situ high-temperature X-ray diffraction. Bi nanowires were fabricated by a pulsed electrodeposition technique within the porous anodic alumina membrane. The relationships between the orientation and diameter of Bi nanowires and the corresponding thermal properties are deduced solely from experimental results. It is shown that the melting point decreases with decreasing nanowire diameter, and there is an anisotropic thermal expansion property of Bi nanowires with different orientations and diameters. The transition of the thermal expansion coefficient from positive at low temperature to negative at high temperature for Bi nanowire arrays was analyzed and discussed.     

A wavelet-Galerkin method for high order numerical differentiation

Numerical differentiation is a classical ill-posed problem. In this paper, we propose a wavelet-Galerkin method for high order numerical differentiation. By an appropriate choice of the regularization parameter an order optimal stability estimate of Hölder type is obtained. Some numerical examples show that the method is effective and stable.     

Effect of Metallic Salts of Pimelic Acid and Crystallization Temperatures on the Formation of β Crystalline Form in Isotactic Poly(propylene)

The effect of crystallization temperatures (100–140°C) on the formation of β crystalline form in isotactic polypropylene nucleated by pimelic acid and sodium, magnesium, zinc, calcium, barium and aluminium salts of pimelic acid has been investigated. It is found that β crystalline form can be produced from polypropylene melt, isothermally crystallized at 120 or 130°C. Aluminium pimelate is a α nucleator which suppresses the production of β crystalline form in polypropylene. Pimelic acid and magnesium pimelate are weak β nucleators. Sodium pimelate is a moderate β nucleator. Zinc pimelate, calcium pimelate and barium pimelate are good β nucleators for polypropylene with calcium pimelate being the best.     

Global existence and the low Mach number limit for the compressible magnetohydrodynamic equations in a bounded domain with perfectly conducting boundary

We study the compressible magnetohydrodynamic equations in a bounded smooth domain in ${{\mathbb{R}}^2}$ with perfectly conducting boundary, and prove the global existence and uniqueness of smooth solutions around a rest state. Moreover, the low Mach limit of the solutions is verified for all time, provided that the initial data are well prepared.     

Studies of super-short pulse generated by a free-electron lasers at perfect synchronism

Three-dimensional （3D） simulations and theoretical analyses on super-short pulse generated using free- electron lasers （FELs） at perfect synchronism are carried out with the help of our 3D OSIFEL code. The evolution of longitudinal pulse width in the Japan Atomic Energy Research Institute （JAERI） experiment is simulated. The results show that the optical pulse is compressed on successive passes due to the slippage between the optical and electron beams, and an ultra-short 221-fs optical pulse is finally obtained, which agrees with the experiment. Furthermore, to shorten wavelength such as soft ultraviolet （SUV） spectrum range, an ultra-short pulse generated at perfect synchronism is analyzed and studied. Finally, the relationship between the optical pulse length compressed and the peak electron beam current is calculated. It shows that the higher the electron beam current, the shorter the output FEL width length, due to the higher gain.     

Low-temperature heat capacities and thermodynamic properties of n-undecylammonium bromide monohydrate C11H28BrNO(s)

Crystal structure of n-undecylammonium bromide monohydrate was determined by X-ray crystallography. Low-temperature heat capacities of the compound were measured by a precision automated adiabatic calorimeter over the temperature range from 78 to 390?K. Two solid–solid phase transitions were observed for the title compound. The temperatures, molar enthalpies, and entropies of the phase transitions were derived based on the analysis of heat–capacity curve. Two polynomial equations of heat capacities as a function of temperature were fitted by least-squares method. Based on the two polynomial equations, smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15?K were calculated and tabulated at 5 K intervals.