A new method of characterization for stratified thermal energy stores

A new method for characterization of stratified thermal energy stores (TES) that integrates both the first law and the second law concerns is presented here. The first law concern is incorporated into a quantity called energy response factor and the second law concern into an entropy generation ratio. A product of these two quantities is at the heart of the TES efficiency definitions. This approach removes the overemphasis of the existing methods either on the first or the second law of thermodynamics which often biases the characterization results. The information about the evolution of the temperature field of the system in time is the prerequisite of the new method. It may be obtained from experiments or from suitable numerical simulations. The current method can be easily integrated into computational fluid dynamic (CFD) simulations and thus facilitate CFD-based design analysis. As an example of such CFD-integrated analysis, a large-scale hot water seasonal heat store is numerically studied to identify the effects of aspect ratio, containment shape, internal structures, and containment size on their efficiency. The results suggest the effectiveness of the new method in deriving useful design insights.     

氮化镓低维纳米结构的制备与表征

主要是以氧化镓为原料,通过气相沉积法,制备出GaN纳米线和纳米带.通过X-射线衍射（XRD）,扫面电镜（SEM）和高分辨透射电镜（HRTEM）等测试手段对其形貌进行了表征和分析.研究了实验过程中工艺条件的改变对所制备GaN纳米结构形貌特征的影响.对两种GaN纳米材料的拉曼散射光谱进行了分析.     

CVD金刚石工具膜生长特征SEM观察

本文用不热形变栅状直丝化学气相沉积（ＣＶＤ）法生长金刚石膜，在Ｓｉ及ＷＣ－Ｃｏ硬质合金衬底上金刚石膜晶面显露规律随衬底温度和甲烷浓度而异，经适当表面处理及选择合适的工艺条件，当生长初期衬底上就呈现出良好晶形的沉积膜，衬底与膜之间的粘结力能得到提高。Ｒａｍａｎ谱分析表明此膜仅具有特征金刚石１３３２ｃｍ￣（－１）峰，通过ＳＥＭ观察揭示出盒刚石膜可在表面、侧面及棱上生长，并与衬底有良好的联结。     

A new surface characterization technique: RIMAPS (Rotated Image with Maximum Average Power Spectrum)

This work introduces a new imaging technique, Rotated Image with Maximum Average Power Spectrum (RIMAPS), for use in determining orientation and characteristics of surface topography. It consists of computing the maximum value of the averaged power spectrum, given by one step of the two‐dimensional Fourier transform, for each angle of rotation of a digitized image. The basic measurement science of this technique is described and different cases are studied. The characterization of simple geometrical figures explains the meaning of peaks and their angular positions given by RIMAPS analysis. A known surface pattern made on a sample of pure copper, mechanically ground, is used to study reproducibility, dependence on image quality and topography scale relative to pixel size and magnification. Samples of pure zinc, mechanically ground and chemically etched, were used to show the main features of RIMAPS analysis when characterizing a more complicated pattern on a real surface. All the studies performed under different conditions for observation and acquisition of images give strong evidence of the stability and robustness of RIMAPS as a technique for the characterization of topography.     

Screening of supports for the immobilization of pectinmethylesterase from acerola (Malpighia glabra L)

A partially purified extract of pectinmethylesterase (PME) from acerola fruit was immobilized on various supports: glass, celite, chrysotile, agarose, concanavalin A Sepharose 4B, egg shell, polyacrylamide and gelatin. In addition, reticulation with glutaraldehyde was assessed, as well as the use of gelatin in the presence of celite, glass and silica. The highest immobilization yields were obtained when the pectinmethylesterase was immobilized in concanavalin A Sepharose 4B (81.7%) and in gelatin‐water (78.0%). Copyright © 2004 Society of Chemical Industry     

Instrumental characterization of clay by XRF,XRD and FTIR

Instrumental characterizations of the clay were performed by different techniques such as XRF, XRD and FTIR. XRF shows the chemical compositions of the clay where Al-oxide and silica oxide are present in major quantity whereas XRD confirms the presence of these minerals in clay. FTIR studies show the presence of quartz, alumina, haematite and different mineral matters.     

Electron spectroscopies and their use for materials characterization

We present here a general overview of electron spectroscopies from a practical point of view. The most frequently used ones are described and the type of structural information they can provide on materials is explained in relation to the physical processes on which they are based. Furthermore, we explore critically and in detail various tools that have been developed to allow a systematic solving of structures by these spectroscopies.     

企业材料耗用的统计分析与评价

本文利用回归分析导出材料耗用的回归方程 ,并对方程进行拟合优度检测和显著性检验 ,以及对材料耗用情况进行综合评价。     

Young’s modulus of crystalline C60 nanotubes studied by in situ transmission electron microscopy

Bending tests of crystalline nanotubes composed of fullerene C₆₀ molecules are performed inside a high-resolution transmission electron microscope. We fixed one side of a C₆₀ nanotube with a body-centered tetragonal structure with typical inner and outer diameters, i.e., 180 nm and 510 nm, respectively, and then applied concentrated forces on the other side using piezomanipulation of a silicon nanotip. The bending process was observed in situ by transmission electron microscopy with simultaneous measurements of the forces by an optical deflection method. It was found that the Young’s modulus of the nanotube was estimated to be 62–107 GPa, which was 1.1–3.3 times larger than that of C₆₀ nanowhiskers. The result concerning the increase in the Young’s modulus of the C₆₀ nanotube provided an experimental evidence for the structural model composed of an inner core and a surface shell for C₆₀ nanowhiskers.