Simulation studies on the fuel electrode of a H2---O2 polymer electrolyte fuel cell

The macro-homogeneous porous electrode theory is used to develop a model which describes the catalyst layer of the hydrogen electrode formed by catalyst particles that are bonded to the membrane. The water transport in the catalyst layer and polymer electrolyte membrane is considered. The effects of catalyst layer structure parameters such as polymer volume fraction, catalyst layer thickness, platinum loading and reactant gas humidity as well as CO poison on the hydrogen electrode behavior are examined. The results show that the catalyst layer thickness has a significant effect on the electrode performance. A thicker catalyst layer will result in a larger ohmic voltage loss and higher catalyst cost. The optimal polymer volume fraction and catalyst layer thickness are 0.5 and 1.5–4 μm, respectively, for this electrode. An optimal platinum surface coverage on carbon need not exceed 20% (20 wt% Pt/C). Larger platinum coverage will increase the cost, but only slightly enhance the electrode performance.     

Determination of the solubility parameter of poly(ethylene oxide) at 25°C by gas-liquid chromatography

The solubility parameter of poly(ethylene oxide) at 25°C has been determined using the method developed by DiPaola-Baranyi and Guillet, by the extrapolation of the values of the interaction parameter χ, at high temperatures, ranging from 70°–90°, 90°–110° and 110°–130°C down to 25°C. The values of the solubility parameter obtained, depending on the temperature ranges employed, are 9.8, 9.9 and 10.1, respectively.     

青酶胺的研究现状及展望

本文详述了青酶胺的性质、应用和研究现状并展望其发展方向。     

氨法处理硫酸装置尾气生产亚铵的实践

介绍用氨法处理硫酸装置尾气生产亚硫酸铵的工艺流程、控制指标、主要设备和生产运行情况。实践表明,氨法SO2吸收率高,可实现装置尾气达标排放,但也存在产品品位较低的问题。对问题进行了分析并提出改进意见。     

PRO/Ⅱ软件在硫磺回收中的二次开发应用

硫磺回收装置的设备需要有较大的操作弹性。针对其过程气进口压力低，手工计算难于进行严格的全程压降计算，现以PRO／Ⅱ软件为开发平台，通过扩充数据库和建立模拟流程，成功地将其用于硫磺回收装置的设备选型和核算，为工程设计提供了先进的计算手段。     

区域烧结法制备高温气体清洁用大尺寸陶瓷过滤管

用区域烧结在1 d内可完成高温气体清洁用1.5 m陶瓷过滤管的制备过程,区域烧结的优势是缩短研究和开发周期.目前,经过认真设计,已经完成区域烧结设备.多孔陶瓷件比致密陶瓷件更容易烧结成型,原因是多孔陶瓷在区域烧结期间可免除其收缩和变形.     

高炉用石墨砖的现状及问题

介绍了近年来我国高炉用石墨砖的进展和存在的问题，提出了高炉用石墨砖的改进方向。     

石油勘探开发行业可持续发展战略研究

从可持续发展的基本内涵出发，初步研究了石油勘探开发行业可持续发展的主要特征和指导原则，并提出了石油勘探开发行业可持续发展的若干主要对策。将可持续发展思想和战略逐渐融进石油工业业务活动中去，对我国石油工业的持续稳定发展具有十分重要的意义。     

Methane Transport Capacity of Rice Plants. II. Variations Among Different Rice Cultivars and Relationship with Morphological Characteristics

Of the total methane (CH4) emitted from a rice field during the growing season 60–90% is emitted through the rice plants. We determined the methane transport capacity (MTC) of rice plants at different physiological growth stages using an automatic measuring system under greenhouse conditions. A total of 12 cultivars (10 inbred varieties and 2 hybrids) were studied in sets of two experiments and was distinguished into three groups according to the patterns of MTC development. MTC is generally increasing from seedling stage to panicle initiation (PI), but differs in the development from PI to maturity. While the hybrid showed a gradual increase in MTC, the inbred cultivars showed either minor changes in MTC or a drastic decrease from flowering to maturity. Among tall cultivars, Dular showed the highest MTC, followed by B40; the lowest MTC was found in Intan. High-yielding dwarf cultivars showed MTC in the descending order of IR72 > IR52 > IR64 > PSBRc 20. New plant type cultivars showed very low MTC with IR65600 exhibiting the smallest MTC at PI, flowering, and maturity. Hybrids (Magat and APHR 2) showed the largest MTC that continued to increased with plant growth. The MTC patterns were attributed to growth parameters and the development of morphological characteristics of the aerenchyma. These results suggest that in tall, dwarf, and NPT cultivars, increase in root or aboveground biomass during initial growth determines a corresponding increase in MTC. Once aerenchyma has fully developed, further increase in plant biomass would not influence MTC. However, in the case of hybrids, a positive relationship of MTC with root + shoot biomass (r = 0.672, p 0.05) and a total plant biomass including grain (r = 0.849, p 0.01) indicate continuous development of aerenchyma with plant growth, resulting in enhanced MTC. In all cultivars, tiller number, but not height, was linearly related to MTC, indicating that the number of outlets/channels rather than plant size/biomass determines the transport of CH₄. These results clearly demonstrate that rice cultivars differ significantly in MTC. Therefore, the use of high-yielding cultivars with low MTC (for example, PSBRc 20, IR65598, and IR65600) could be an economically feasible, environmentally sound, and promising approach to mitigate CH₄ emissions from rice fields.