Effect of Ni and SAPO-34 co-additive on enhancing hydrogen storage performance of MgH2

The hydrogen storage performances of MgH₂ improved by the addition of Ni and SAPO-34 were studied in detail. The mixture of MgH₂ with Ni and SAPO-34 was a physical reaction as shown by the X-ray diffraction (XRD) results. The SAPO-34 and Ni were uniformly distributed on the surface of MgH₂. The thermodynamic and kinetic properties of 90MgH₂/5Ni/5SAPO-34 were investigated by differential scanning calorimetry (DSC) and pressure-composition-isothermal (PCI) methods. The results showed that the dehydrogenation activation energy of 90MgH₂/5Ni/5SAPO-34 decreased by 64.3 kJ/mol compared with that of MgH₂. In addition, the relationship between the value of dehydrogenation heat and hydrogen content was also investigated by in-situ calorimetry. The enthalpy value of each sample in the dehydrogenation processes were calculated by in-situ calorimetry measurement. The dehydrogenation enthalpies of as-milled MgH₂ and 90MgH₂/5Ni/5SAPO-34 were 63.2 kJ/mol H₂ and 53.6 kJ/mol H₂, respectively. Thus, the co-doping of Ni and SAPO-34 contributed significantly to decrease the thermodynamic stability and improve the hydrogen sorption kinetic properties of MgH₂.     

基于过程模拟和随机森林模型的生物质制氢过程因素分析与预测

生物质可以替代化石燃料,减少温室气体排放,是一种有前途的可再生能源。生物质通过化学链气化制备氢气,碳化活化制备活性炭,两条工艺路线耦合可以联产绿色能源氢气和具有高附加值的活性炭,但是原材料选择和工艺参数优化成为规模化生产的主要障碍。在生物质联产氢气和活性炭工艺模型的基础上,建立高性能的随机森林预测模型,并探究生物质组分、工艺参数和过程产物对联产工艺的相对重要性。结果表明:生物质组分中的灰分、碳元素、氢元素的含量以及气体重整温度和水蒸气用量是准确预测氢气浓度和产量的重要影响因素。其中,重整温度、合成气中氢气浓度、水蒸气用量三个影响因素对氢气浓度的影响高达61%,活化剂用量、水蒸气用量两个因素对氢气产量的影响高达63%。此外,基于随机森林模型对生物质制氢过程中的因素进行分析和优化,可以实现氢气浓度达到96.8%(体积)。     

TDI改性原子灰用不饱和聚酯树脂的研究

针对我国高速列车涂装中对原子灰的特殊需求,采用TDI(2,4-甲苯二异氰酸酯)对不饱和聚酯树脂改性。结果表明:改性后的不饱和聚酯树脂原子灰的柔韧性、耐冲击性均得到了改善,从而提高了高速列车外表大修的运行里程。     

三峡水库蓄水后铜陵河段演变特点及趋势分析

长江下游铜陵河段为典型的鹅头型多汊河道,通过对三峡水库蓄水前后该河段水沙特性、深泓线、平面形态和断面冲淤变化的分析,结论表明,受三峡水库运行和上游水土保持工程的影响,该河段上游的大通站来沙量大幅减少,河段内各汊道发生相应的调整。其中成德洲右汊和南夹江汊道冲刷发展,成德洲左汊进口有所淤积,造成成德洲右汊和南夹江汊道分流比逐渐增大,对南夹江的防洪造成不利影响。建议采取适当的治理措施,防止河势向不利防洪和航运方向进一步发展。     

碳微晶结构对球磨制备镁基储氢材料的影响

以杏壳活性炭和煤基碳作为镁粉的助磨剂,用氢气反应球磨法制备了镁基储氢材料,对比研究了这两种不同微晶结构的碳在制备镁基储氢材料时作用的差异。结果表明,杏壳活性炭和煤基碳都是镁粉的有效助磨剂,能防止镁粉发生"冷焊"及粘附现象,得到分散的纳米级镁基储氢材料。杏壳活性炭对镁粉的分散性优于煤基碳,但用煤基碳作助磨剂所制得粉体的粒度更小,储氢密度更大,放氢温度更低。     

凹凸棒石的提纯及改性对其吸附性能的影响

对凹凸棒石原土进行提纯,然后分别用盐酸、NaCl、热活化、微波进行改性处理,以亚甲基蓝吸附量作为凹凸棒石吸附性能指标。结果表明,自然沉降法提纯能使凹凸棒石的吸附能力略有提高,盐酸改性能显著提高凹凸棒石的吸附能力,NaCl、热活化、微波的改性效果依次降低,改性剂浓度、热活化温度、微波处理时间过低或过度都不利于提高凹凸棒石的吸附能力。     

新水沙情势下长江中下游干流岸线保护研究——以扬中市2017年江堤崩岸治理为例

近十几年来随着水沙情势的显著变化,长江中下游干流崩岸险情频发,加强崩岸治理和岸线保护是沿江防洪安全和经济发展的重要保障。在梳理三峡水库蓄水以来坝下游水沙情势变化、河道冲刷和崩岸情况的基础上,以2017年11月江苏省扬中市江堤崩岸为例,分析崩岸段近期河道演变特征和地勘资料,认为河槽持续冲刷下切贴岸及二元土质结构河岸是崩塌的主要原因,而2016~2017年连续大洪水加了快崩岸的发生。崩岸发生后立即实施了窝塘抢护并修筑临时挡水子堤,随后实施完成干堤复建和窝塘上下游岸线守护工程,实现了2018年成功度汛。此次崩岸的特点和原因在长江中下游较为典型,对崩岸治理与岸线保护具有启示作用。     

CCCW应用于盾构法预制管片中的两种施工工艺

对比介绍了水泥基渗透结晶型防水材料（CCCW）在地铁盾构法施工预制管片生产中的干撒法和涂刷法两种施工工艺。     

Experimental study on flow behavior at open channel confluences

Channel confluences are common in natural rivers and hydraulic engineering, and the flow behavior at confluences becomes very complex because of the interaction between the tributary and the main river. In this study, the experiments were performed in a combined flume with a 30° angle between the main and tributary flume located at Sichuan University. The velocity was measured by using a three-component acoustic Doppler velocimeter (ADV) over a grid defined throughout the junction region. Based on the analysis of the velocity at the confluence, the distinctive characteristics of a channel confluence flow may be divided into several zones including a zone of separation immediately downstream of the junction branch channel, the maximum and minimum velocity regions at the upstream and downstream in the confluent channel, and a shear plane developed between the two combining flows downstream of the confluent channel. In addition, secondary circulations in different directions at the higher and lower velocity zones are observed as well. Translated from Journal of Sichuan University (Engineering Science Edition), 2006, 38(2): 1–5 [译自: 四川大学学报 (工程科学版)]     

纳米Sn／SnO2／石墨复合材料作为锂离子电池负极材料的研究

以氯化锡、氨水和无水乙醇为原料,采用溶胶一凝胶法制备纳米SnO2粉末,并与石墨、葡萄糖共热制备Sn／SnO2／石墨复合材料。用X射线衍射分析、透射电镜和电化学测试对材料进行了表征。采用该方法制备出的Sn／SnO2／石墨复合材料可逆容量可达680mA·h·g^-1,经过20次循环后容量基本稳定在380mA·h·g^-1。