关于竹桩复合地基工程实测及理论的探讨

应用土力学的基本原理,根据工程实测数据,对竹桩复合地基的承载力、变形和固结特征进行了探讨,认识了其性能的实用性和科学性。     

A “proton pump” concept for the investigation of proton transport and anode kinetics in proton exchange membrane fuel cells

A novel concept for the measurement of proton transport properties and electrode kinetics in proton exchange membrane fuel cells (PEMFC) is presented. The “proton pump” is essentially a fuel cell operated with pure nitrogen or very low hydrogen partial pressure instead of oxygen-containing gas on the cathode side, avoiding the complicated electrode kinetics of oxygen reduction. In this first study using this concept, we investigated the proton transport in high temperature PEMFC based on polybenzimidazole (PBI)/phosphoric acid membranes. The impedance spectra of the proton pump allow the clear distinction between anode and cathode kinetics and proton transport in the membrane. Identifying and analyzing the contribution of the anodic processes in the impedance spectra enabled the quantitative investigation of anode kinetics based on the Butler-Volmer equation. The proton transport was investigated in more detail in the current saturation region, where proton transport turned out to be the limiting process in case of sufficient H₂ supply at the anode. The maximum proton transport capacity of the PBI/phosphoric acid membrane was found to be comparable to those of Nafion^® membranes.     

Fatty Acid Composition, Antioxidant Properties, and Antiproliferative Capacity of Selected Cold-Pressed Seed Flours

Cold-pressed seed flours from pumpkin, parsley, mullein, cardamom, and milk thistle were examined for total oil, fatty acid profile of the oil, total phenolic content (TPC), scavenging activities against peroxyl (ORAC), hydroxyl (HOSC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) (RDSC) radicals, and antiproliferative capacity against HT-29 human colon cancer cells. The cold-pressed parsley seed flour contained a very high concentration of total oil—17.6 g/100 g flour—with primarily C18:1 fatty acid at 86.2 g/100 g fatty acids. All other flour oils had relatively high levels of saturated fats, ranging from 39.0 to 62.9 g/100 g fatty acids. The tested seed flours demonstrated significant TPC and free radical scavenging activities. Milk thistle seed flour had the highest TPC value of 25.2 mg gallic acid equivalent per g flour (GAE mg/g) followed by that of parsley seed flour at 8.1 GAE mg/g. Milk thistle seed-flour extract also had significantly higher antioxidant activities than all other extracts against all tested radicals. The milk thistle seed-flour extract had an ORAC value of 1131 μmol trolox equivalents (TE) per g flour (TE μmol/g), a HOSC value of 893 TE μmol/g, and an RDSC value of 61 TE μmol/g. Also, ORAC, HOSC, and TPC values were significantly correlated (P < 0.01) under the experimental conditions. The cold-pressed milk thistle seed flour inhibited the proliferation of HT-29 cancer cells in a dose-dependent manner. Results from this study suggest that these cold-pressed seed flours may serve as natural sources of antioxidants and may be used to improve human health.     

合成氨扩能改造中锅炉存在的问题及采取的措施

针对天脊集团年产30万t合成氨扩能改造,给2台225t/h高压锅炉带来的除氧器热量过剩、锅炉给水温度升高、主蒸汽温度降低等一系列问题,分析了产生问题的原因,从节约能源、提高锅炉效率考虑,提出了相应的解决问题的办法:利用热量分流、改造省煤器管、增加二级过热器受热面积。经过3年多的生产实践证明,取得了良好的效果。     

2006-2007年国外环氧树脂工业进展

综述了2006~2007年国外环氧树脂工业原料及树脂供求和价格变动以及产能扩充、公司并购情况。介绍了环氧树脂、固化剂及助剂方面的新产品以及新型环氧树脂胶粘剂、涂料、大飞机用复合材料等的开发进展。     

湿法磷石膏堆场水与环保

针对降雨量和蒸发量的不确定性,依据磷石膏堆场回水和环保要求,提出降雨量和蒸发量生产保证率和环保保证率两个设计参数.以堆场水平衡计算盈亏平衡为控制目标,确定堆场调节库容和合理设置回水量.     

疏桩-筏板基础在电站厂房中的应用研究

介绍中国成达工程公司在印尼LABUAN 2×300MW燃煤电站总承包项目中采用疏桩—筏板复合基础方案来处理地基承载力及变形问题,并分析了疏桩基础的工作机理、适用范围和设计方法。实践证明疏桩复合地基具有良好的技术性能和经济效益,可供类似工程参考。     

带补燃余热流化床锅炉改纯低温余热发电

根据节能减排等形势的需要,浙江虎山集团对原来205000t/d水泥生产线的余热(带补燃)流化床锅炉电站实施了纯低温余热电站的改造。文章详细介绍了其两台锅炉、汽轮机组及相应的辅机设备的具体改造内容及改造过程中关键问题的处理;同时对改造后的纯低温余热发电系统工艺流程、技术参数、运行情况和影响因素也进行了相应介绍及分析探讨。     

间歇过滤机最佳生产周期的图解求法

用图解法求出间歇过滤机在过滤介质阻力不可忽略和可以忽略的两种情况下的最佳生产周期,与化工原理教材中提供的解析法比较表明:图解法更为直观,生产能力的意义更加明确。     

低温开放体系配阴离子对合成硅基铝多孔材料的影响

以十六烷基三甲基溴化铵为模板,六水氯化铝和十八水硫酸铝在低温开放体系分别与正硅酸乙酯直接进行固/液反应,合成非晶结构的铝掺杂氧化硅微介孔材料。并用XRD、HRTEM、SEM/EDS、低温N2吸附、FTIR和原子吸收光谱TAS等技术对产物的结构和吸附性能进行表征。探讨了微介孔的形成机理。结果表明,在酸性和阳离子表面活性剂共存条件下,所制得的铝掺杂氧化硅微介孔材料呈不规则形状,其孔壁均为无定型;掺杂金属铝进入氧化硅晶格。铝源中配阴离子不仅影响材料的物相织构、材料的元素组成,而且还影响其吸附性能。