Normalization and noise-reduction algorithm for fringe patterns

This paper presents a fringe pattern normalization and noise-reduction algorithm. Locally the background noise is suppressed, the modulation normalized and the noise smoothed. An expression to calculate the cosine-only term is formulated. It is related to the directional derivatives of the intensity fringes. Two-dimensional Fourier series are used to calculate the parameters needed for the algorithm. Experimental work is presented using diffraction and ESPI images. The programming is relatively simple and involves mainly local convolutions. The processing time using a 2 GHz computer to normalize an image of 256 × 256 pixels is approximately one second.     

垂直低温两相流管底液氮汽泡上升速度的实验研究

本文对垂直低温两相流管底部液氮汽泡的上升速度运用高速摄像机进行了可视化实验研究,对所采集的实时图像进行处理.在Cole和Mendelson汽泡上升速度经验公式的基础上,通过对液氮汽泡的上升速度的分析,提出了圆管管路底部液氮汽泡的上升速度的拟合公式,分析研究其变化规律,为进一步探求圆管内液氮弹状汽泡的生成机理提供依据.     

Phase diagram of Na2S2O3 + ethanol + water at ambient pressure and temperature

In the present communication, we report the studies concerning liquid–liquid–solid equilibria for the ternary system sodium thiosulphate (Na₂S₂O₃) + ethanol + water at ambient pressure and at room temperature (303 ± 2 K). The solubility data of Na₂S₂O₃ are reported for solutions in water, ethanol and solutions of varying concentrations of ethanol in water. The phase diagram for the said system is developed, described and compared with similar system K₂CO₃ + methanol + water. These results have been explained in terms of structural properties of aqueous ethanol solutions and further discussed in terms of the effect of ions to cause phase separation.     

Topological order in the phase diagram for high-temperature superconductors with point defects

Applying a Lindemann like criterion obtained previously by Kierfeld et al. [J. Kierfeld, T. Nattermann, T. Hwa, Phys. Rev. B 55 (1997) 626], we estimate the magnetic field and temperature for a high-T_c superconductor, at which a topologically ordered vortex glass phase becomes unstable with respect to a disorder-induced formation of dislocations. The employed criterion is shown to be equivalent to a conventional phenomenological Lindemann criterion including the values for the numerical factors, i.e., for the Lindemann number. The positional correlation length of the topologically ordered vortex glass is calculated.     

Calculating Gibbs free energies of transfer from Gibbs ensemble Monte Carlo simulations

The partitioning of the ternary systems n-pentane/n-heptane/(helium or argon) at ambient conditions is investigated using configurational-bias Monte Carlo simulations in the Gibbs ensemble. The results demonstrate that this approach yields very precise partition constants and free energies of transfer. Simulations are carried out to study the dependence of the n-pentane partitioning with respect to the carrier gas, the system size, and the overall solute concentrations. None of the changes of variables, within the ranges used here, has a significant effect on the alkane partitioning. However, chemical potentials calculated via Widom's ghost particle insertions show a strong number dependence for phases containing relatively few molecules of a given type. This problem originates from the fact that the chemical potential is calculated for a concentration of real particles plus one ghost particle that is systematically larger than the equilibrium concentration. A simple correction term is suggested to account for this problem. Received: 13 May 1998 / Accepted: 18 June 1998 / Published online: 4 September 1998     

偶氮侧基聚合物光致异构动力学研究

本文对偶氮侧基聚合物相位共轭光时间特性进行了研究,得到了相位共扼光产生机制─光致异构过程的时间常数.在相位共轭光上升阶段,其时间常数在0.4～0.5s之间,在相让共轭光的衰减过程,衰减满足双指数关系,分段拟合得到较好的结果,且得到快过程的时间常数为0.27s,慢过程的时间常数为0.78s.     

La（NCS）3.4.5H2O和B15C5在乙醇中的相平衡及热化学研究

采用半微量相平衡方法测定了三元体系Ｌａ（ＮＣＳ）３．４．５Ｈ２Ｏ－Ｂ１５Ｃ５－Ｃ２Ｈ５ＯＨ在２９８．１５Ｋ的溶解度，测定了各饱和溶液的折光率。     

微波相转移催化合成DL—苯丙氨酸

在微波作用下,仅用1min便完成了苯甲醛亚胺的固—液相转移催化苄基化反应,然后经酸水解得到d1—苯丙氨酸,全程总产率为62.5×10(-2)。     

铕离子探针研究Al2O3的相变过程

氧化铝具有许多重要的工业用途，而制备高热稳定活性氧化铝的技术也在不断地发展[1，2]，因此，研究其高温烧结下的相变过程很有意义．离子深法作为新型测试手段，已成功地用于生物大分子结构与功能研究方面［‘］，而在固体材料测试中的应用尚未见报道．我们以EU’“作为荧光探针，并结合＊＊D和＊nR研究了川对。在不同烧结温度下的相变过程．1实验部分样品的制备采用复盐分解法．先将Elf刀s用高纯硝酸溶解定容．以占AlzO。重量1％的量加入到硫酸铝锭溶液中，进行超声处理，冷冻干燥．再依次登于900”C、1000C、1100C、1200C的高温炉…     

聚合物连续分级

本文较系统地介绍了聚合物连续分级的理论基础、实验室装置及其实际应用。