Bayesian linear prediction in finite populations

In this paper, Bayesian linear prediction of the total of a finite population is considered in situations where the observation error variance is parameter dependent. Connections with least squares prediction (Royall (1976, J. Amer. Statist. Assoc., 71, 657–664)) in mixed linear models (Theil (1971, Principles of Econometrics, Wiley, New York)), are established. Extensions to the case of dynamic (state dependent) superpopulation models are also proposed.     

Transient dynamical behavior and phase transitions in magnetic systems

It was recently suggested that transient dynamical properties were of some use to predict equilibrium critical properties of 2D and 3D models of statistical mechanics on the lattice. We investigate such dynamical properties for three related models with competitive interactions, namely the ANNNI model, the brickwork model, and the BNNNI model. In spite of known differences in their equilibrium phase diagrams, our simulations display similar transient dynamical behaviors for all three models. The reliability of this method for probing equilibrium properties seems therefore questionable even for rather simple magnetic models without any structural disorder.On leave from Centre de Physique Théorique, Ecole Polytechnique, 91128, Palaiseau Cedex, France.     

Phase determination in holographic Moiré in presence of nonsinusoidal waveforms and random noise

This paper proposes a subspace parameter estimation method which besides allowing for accommodating multiple PZTs in an optical interferometer permits for extracting in real time values of phase shifts between data frames at each pixel point. The technique enables to freely choose values of phase shifts between 0 and π. A generalized phase measurement algorithm allows for computing multiple phase information present in the interferometer. The method facilitates the use of spherical beams, addresses errors arising from the miscalibration of the phase shifting devices, and is capable of handling nonsinusoidal waveforms in an effective manner. Numerical simulations demonstrate that phase distributions can be measured with high accuracy even in the presence of noise.     

A facile one-pot synthesis of β-keto sulfones from ketones under solvent-free conditions

An easy solvent-free method is described for the conversion of ketones into β-keto sulfones in high yields that involves the in situ generation of α-tosyloxyketones, followed by nucleophilic substitution with sodium arene sulfinate in the presence of tetra-butylammonium bromide at room temperature. The salient features of this one-pot protocol are short reaction times, cleaner reaction profiles, and simple work-up that precludes the use of toxic solvents.     

THE ERRORS ESTIMATION OF THE CHEBYSHEV SPECTRAL－DIFFERENCE METHOD FOR TWO－DIMENSIONAL VORTICITY EQUATION

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Formation of porous poly(vinylidene fluoride) membranes with symmetric or asymmetric morphology by immersion precipitation in the water/TEP/PVDF system

The phase equilibrium boundaries of the membrane forming system, water/triethyl phosphate (TEP)/PVDF, at 25 °C were determined experimentally using cloud-point and equilibrium absorption methods. Based on the phase diagram, appropriate dope and bath compositions were selected to prepare microporous membranes by means of the isothermal immersion-precipitation technique. As a metastable casting dope with respect to crystallization was adopted, the formed membranes exhibited a uniform cross-section composed of interlocked crystal elements coexisting with the network of continuous pores, as was revealed by high resolution FESEM imaging. Morphologies of the membranes’ top surfaces were found to depend heavily on the bath strength, which was controlled by the TEP content. By changing the bath gradually from pure water to 70% TEP, the top surface evolved from a dense skin (asymmetric membrane) to a totally porous morphology (symmetric membrane). Wide angle X-ray diffraction analysis indicated that PVDF crystallized into α-type structure for all of the synthesized membranes. The crystallinity as determined from diffraction peak deconvolution was ≈65%, which value was confirmed by Differential Scanning Calorimetry (DSC). The obtained thermograms also showed a similar melting peak temperature (T_m ≈ 169 °C) for all membranes. Furthermore, water fluxes and tensile strengths of the membranes were measured. The results were found to correlate with the morphologies of the membranes.     

In situ X-ray observation of phase transformation in Fe2O3 at high pressures and high temperatures

A laser-heated sample in a diamond anvil cell and synchrotron X-ray radiation was used to carry out structural characterization of the phase transformation of Fe₂O₃ at high pressures (30-96 GPa) and high temperature. The Rh₂O₃(II) (or orthorhombic perovskite) structure transforms to a new phase, which exhibits X-ray diffraction data that are indicative of a CaIrO₃-type structure. The CaIrO₃-type structure exhibited an orthorhombic symmetry (space group: Cmcm) that was stable at temperatures of 1200-2800 K and pressure of 96 GPa (the highest pressure used). Unambiguous assignment of such a structure requires experimental evidence for the presence of two Fe species. Based on the equation of state of gold, the phase boundary of the CaIrO₃-type phase transformation was P (GPa)=59+0.0022×(T−1200) (K).     

BP神经网络电子束扫描均匀度校正系统

 电子束的扫描均匀度是工业辐照电子直线加速器的重要技术指标，该校正系统利用人工神经网络中的误差反向传播法可以对扫描电流波形进行校正，以克服扫描磁场引起的电子束形状变化、位置改变等造成的电子束分布的不均匀性，从而使扫描曲线的归一化均方偏差达到1.8%。     

边界元法在带可动边界的瞬时热传导问题中的应用

该文利用边界无法对二维瞬时传热和相变问题进行求解。采用空间二次曲线单元对边界进行离散化,并采用时间相关基本解正确处理了相应边界积分。计算表明该文数值格式稳定,结果与已有文献相比较吻合一致,且该文模式时段可放大,从而提高了计算效能和稳定性。     

增加试验数据对岭估计的均方误差的影响

在线性模型中,对于回归系数的岭估计和广义岭估计,本文给出了选择岭参数的条件,在此条件下,岭估计和广义岭估计不仅能改善LS估计,而且增加试验数据时,它们的均方误差都会减少。同时,本文将增加试验数据换成增加附加信息,从而讨论了附加信息对混合岭估计和混合广义岭估计的影响问题。