Vapour-liquid equilibrium data for binary mixtures of some new refrigerants

The acceptance of the Montreal Protocol has led to a timetable for the phasing out of chlorine-containing refrigerants and their replacement by new chlorine-free materials. For many applications a pure alternative refrigerant can not be found with the appropriate properties and refrigerant mixtures have been considered. In order to model the properties of these refrigerant blends accurate vapour-liquid equilibrium (VLE) data are required over the range of temperature and pressure of interest to the refrigeration engineer. In this paper we report VLE data for six binary mixtures of the new hydrofluorocarbon refrigerants over a wide range of temperatures and pressures. The six mixtures are: R32/R125, R32/R143a, R32/R134a, R125/R143a, R125/R134a and R143a/R134a. Results for R32/R125 and R32/R134a were obtained down to at least −30°C and were done in duplicate. The raw data were correlated to two models using Maximum Likelihood techniques. One of the models was then used to predict azeotropic compositions for three of the mixtures (R32/R125, R32/R143a and R125/R143a) and the approximate composition of a ternary saddle point azeotrope.     

Using micro-synchrotron radiation induced X-ray emission distribution maps to determine correlation between elements in prostate tissue

Elemental maps obtained by micro-synchrotron radiation induced X-ray emission technique can be manipulated in several ways to extract useful information. In this paper the method of displaying the correlation between two or three elements in one correlation map is described. Such types of maps give precise information about the overlap between the elements without distorting the original data.     

编码式光纤光栅传感阵列解调方案的论证

介绍了编码式光栅传感阵列的结构及其传感信号的特点。采用梳状结构对编码式光纤光栅传感阵列进行解调，利用被测光谱通过阵列波导光栅不同通道时输出的不同光强的比值确定被测光的波长。该文分别从理想状态和存在背景反射的状态论证了本文提出的方案的可行性，分析了噪声引起的误差。该系统不但适合于解调大容量的波长信息，而且在解调时不存在任何机械移动部分便可以快速、同时测量多个波长。     

Molecular motions in macromolecules under mechanic and electric force fields

General aspects of the dynamics of macromolecules are reviewed on the basis of a parallel analysis of the material response under mechanical and electric force fields.Long-range (normal and segmental dynamics) as well as short-range motions are studied on the basis of experimental data, correlation function, and memory equation techniques.Accordingly, several methods to describe the relaxational behavior of macromolecules and their pendant molecular groups are proposed.Presented as a keynote lecture at the 4th European Rheology Conference, September 4–9, 1994, Seville, Spain     

多元混合物池内核态沸腾换热关联式研究进展

主要针对三元混合物的池内核态沸腾换热实验及关联式拟合进行了总结.在使用统一的方程(α/αid=1/(1 k))的情况下,将众多研究者提出的对关联式中两个主要元素(理想传热系数αid及影响因子k)的计算方程进行了详细比较.分析了现有关联式的不足,并探讨了多元混合物沸腾换热关联式发展的新动向.     

三维形貌测试系统中的数字信号处理技术

本文采用一种基于数字滤波的正文解调算法,用于三维形貌测试系统中相位分布的计算。文中考察了频域理想低通滤波器、三阶巴特沃思滤波器、有限冲击响应滤波器以及空域均值滤波器,通过分析滤波器性能和比较处理结果,得出均值滤波器或有限冲击响应滤波器比较适用于类似于变形光栅的窄带信号。采用数字处理方法,可以由一帧变形光栅图迅速、精确地重建物体的形貌。     

相关阵在抑制局部相关噪声中的应用

本文提出用阵元间互相关作为基元加权求和形成波束(相关阵)，并给出用来抑制线阵局部强相关干扰的一种权向量实现方法。海上试验数据处理结果表明，利用本文提出的权向量实现相关阵比CBF阵有较高的信噪比增益和较好的抗噪声干扰能力。     

Ellipse detection and phase demodulation for wood grain orientation measurement based on the tracheid effect

The methods of ellipse detection and phase demodulation for determining wood grain orientation are proposed. These methods are based on the tracheid effect—laser beam impinging upon a wood surface forms an elongated laser spot with its direction indicative of the grain orientation. Experimental results show that the method of ellipse detection is suitable for the grain orientation measurement on planed softwood surfaces, while the method of phase demodulation is capable of extracting the grain orientation precisely from laser images with low signal-to-noise ratio, such as the images on the surfaces of hardwood species or roughsawn materials.     

Temperature effects on the structure of liquid D-methanol through neutron diffraction

The study of changes in the structure (H-bonded) of liquid alcohols at elevated temperatures is rare probably due to low flash points of these liquids. An indigenously devised special quartz cell is now used to carry out the structural studies of these liquids at elevated temperatures through neutron diffraction. Here, the liquid consists of deuterated methanol and neutron data was collected on the high-Q diffractometer at Dhruva, BARC. The corrected data at elevated temperatures (BP (boiling point) and double the BP) show that there is a large change in the H-bonded structure of this liquid. The pre-peak or hump, known to be signature of H-bonded clusters appears to be present at all the three temperatures studied. In the low-Q (scattering vector) data Ornstein-Zernike (OZ) behaviour is also observed. It is, however, seen that the intramolecular structure does not change very much at higher temperatures. A detailed model analysis is in progress and would be reported later.     

Subshell-pair correlation coefficients of atoms in momentum space

Angular correlation coefficients τ ^{nl,n^′ l^′} [p] between linear momenta of an electron in a subshell nl and another electron in a subshell n′ l′ are studied for the 102 neutral atoms He through Lr in their ground states, where n and l are the principal and azimuthal quantum numbers, respectively. We theoretically find that electron momenta are negatively correlated or uncorrelated; τ ^{nl,n^′ l^′} [p] < 0 when |l − l′|=1, while τ ^{nl,n^′ l^′} [p]=0 when |l − l′| ≠ 1. Numerical examinations of the atoms show that except for the He–B atoms, negative correlations are largest between 1s and 2p subshells, which have the most diffuse electron distributions in momentum space.