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41.
孙飞 《常州信息职业技术学院学报》2004,3(1):24-26
在b/s结构中可以完全实现逻辑和界面的分离,而它们之问的数据交流只有一个途径:表单提交。实现表单提交的对象化一直是很多程序员的愿甲,水文将通过对struts的介绍末展示其恭本工作原理,阐述如何用struts实现表单提交对象化: 相似文献
42.
甲烷制备高纯度氢气的实验研究 总被引:1,自引:0,他引:1
李传统 《南京师范大学学报》2004,4(4):28-31
对甲烷制备可供质子交换膜燃料电池(PEMFC)用的高纯度氢气进行了实验研究,得出了不同蒸汽/碳比值时甲烷的转化率、不同过量空气系数对制备气体成分的影响、不同压差时氢气在选择性膜中的渗透率以及不同系统压力对氢气反应焓的影响规律.研究结果表明,在蒸汽与甲烷中的碳比例一定时,蒸汽重整反应器内的反应速率和它出口处CO的浓度,随甲烷的流量的增加而提高.提高甲烷蒸汽重整系统的工作温度和压力,可以提高甲烷的转化率,在S/C比值不变的情况下,仅提高温度可提高甲烷的转化率约10%;而将工作压力由0.1MPa提高到0.6MPa,甲烷的转化率提高约21%.甲烷的理论转化率为84.6%,本文实验研究中的最大实际转化率为78.03%,实验研究系统的系统完善度为92.23%,说明该系统还有待完善之处,还可以进一步提高甲烷的转化率.增大PEMFC中选择性膜两侧的压差或提高氢气的纯度,均利于提高氢气混合物的渗透率.该研究为制备符合PEMFC使用条件的氢气提供了可靠依据,同时为综合利用煤层气提供了新的途径。 相似文献
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Lü Manqi 《中国稀土学报(英文版)》2004,22(Z2)
The structure and hydriding performance of La0.6Nd0.4Ni4.8Mn0.2Cux (x = 0 ~ 0.4) alloys were investigated in order to develop suitable materials for metal hydride air conditioner. The effect of Cu addition on the crystal structure,equilibrium pressure, hydrogen capacity and hysteresis as well as hydrogen absorption/desorption kinetics were systematically studied by using the measurement of P-C isotherms, X-ray diffraction and scanning electron microscopy. As the amount of Cu increases, the plateau pressure increases and hydrogen absorption/desorption kinetics is improved, but the effective hydrogen storage capacity decreases. It is shown that variations in the basal plane parameter a can be used as an indication for the plateau pressure changes. With the increase of parameter a, the plateau pressure decreases. For La0.6 Nd0.4Ni4.8Mn0.2Cux(x = 0 ~ 0.4) alloys there is a relationship between the effective hydrogen storage capacities and the ratios of their unit cell parameters c and a. The effective hydrogen storage capacity decreases with increase of a/c. 相似文献
45.
In this study backscattered electron (BSE) imaging was used to display cellular structures stained with heavy metals within an unstained resin by atomic number contrast in successively deeper layers. Balb/c 3T3 fibroblasts were cultured on either 13-mm discs of plastic Thermanox, commercially pure titanium or steel. The cells were fixed, stained and embedded in resin and the disc removed. The resin block containing the cells was sputter coated and examined in a field-emission scanning electron microscope. The technique allowed for the direct visualization of the cell undersurface and immediately overlying areas of cytoplasm through the surrounding embedding resin, with good resolution and contrast to a significant depth of about 2 μm, without the requirement for cutting sections. The fixation protocol was optimized in order to increase heavy metal staining for maximal backscattered electron production. The operation of the microscope was optimized to maximize the number of backscattered electrons produced and to minimize the spot size. BSE images were collected over a wide range of accelerating voltages (keV), from low values to high values to give ‘sections' of information from increasing depths within the sample. At 3–4 keV only structures a very short distance into the material were observed, essentially the areas of cell attachment to the removed substrate. At higher accelerating voltages information on cell morphology, including in particular stress fibres and cell nuclei, where heavy metals were intensely bound became more evident. The technique allowed stepwise ‘sectional’ information to be acquired. The technique should be useful for studies on cell morphology, cycle and adhesion with greater resolution than can be obtained with any light-microscope-based system. 相似文献
46.
A method is described for electron microscopic preparation of cultivated cells for vertical sections using the test chamber system TCSC-1. The cells are cultivated on a special foil. They can be fixed and embedded directly in the chamber. After polymerization of the resin, the foil can be easily taken off and a second resin layer is poured upon the embedded cells. Then distinct cells can be marked under an inverted light microscope. The bilayer of the resin allows optimal conditions for vertical sections of anchorage-dependent cells. 相似文献
47.
Frey B Hartmann M Herrmann M Meyer-Pittroff R Sommer K Bluemelhuber G 《Microscopy research and technique》2006,69(2):65-72
High hydrostatic pressure (HHP) becomes more and more interesting for life science research, since it can be employed to inactivate various cells. To directly monitor "cells under pressure," the development of an optical high-pressure chamber is required. Therefore, an optical pressure chamber that can be used for up to 300 MPa was constructed. This chamber has already been described as a tool for in situ observation of dynamic changes of microscopic structures in bright field as well as phase contrast. In combination with an inverted microscope, we obtained brilliant microscopic color pictures with an optical resolution more than 0.56 microm. Here, we demonstrate the capabilities of the HHP cell, in combination with epifluorescence microscopy. Using a nonadherent human B-cell line (Raji, ATCC CCL 86), stained with the fluorescent dyes propidium iodide, Hoechst 33342, or dihexyloxacarbocyanine iodide, we were able to show that the system is suitable to perform fluorescence microscopic analyses, with pressures up to 300 MPa, with viable mammalian cells. 相似文献
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