Hydrogen sorption properties of nanocrystalline Mg2FeH6-based complex and catalytic effect of TiO2

The diversities of hydrogen sorption properties of Mg₂FeH₆-based complexes with and without TiO₂ were investigated. Mg₂FeH₆-based complexes with and without TiO₂ were synthesized respectively by reactive mechanical alloying, and hydrogen sorption properties of the complexes were examined by Sieverts-type apparatus. The results show that the sample without TiO₂ releases 4.43 % (mass fraction) hydrogen in 1.5 ks at 653 K under 0.1 MPa H₂ pressure and absorbs 90% of the total 4.43 % (mass fraction) hydrogen absorbed in 85 s at 623 K under 4.0 MPa H₂ pressure. But for the sample with TiO₂ addition under the same condition, it only needs 400 s to release all of the stored hydrogen and 60 s to absorb 90% of the total hydrogen absorbed. The activation energies for desorption process of the samples with and without TiO₂ are determined to be 71.2 and 80.3 kJ/(mol·K), respectively. The improvement in hydrogen sorption rate and and reduction in activation energy can be attributed to the addition of TiO₂.     

Isolation and identification of a sulfate reducing bacteria and sequence analysis of its dissimilatory sulfite reductase gene

A sulfate reducing bacteria was isolated from mining sewage of Daqing Oilfield by Hungate anaerobic technology. Physiological-biochemical analysis showed that the strain could utilize polyacrylamide as sole carbon and nitrogen source. The sequence analysis of 16S rDNA illustrated that the similarity of F8 and Desulfovibrio desulfuricans (AF192153) was 99%, and the similarity sequence of dissimilatory sulfite reductase gene (DSR) cloned from the strain and Desulfovibrio desulfuricans (AF273034) was 98%. Their phylogenitic analysis was basically anastomosed, and thus temporarily named as Desulfovibrio desulfuricans F8. The DSR cloned from F8 strain was 2740 bp in length consisting of three ORF, DSRA, DSRB and DSRD as a single operon (DSRABD) regulated by the same operator. DSRA contained typical conservative box of sulfate—sulfite reducing enzyme (SiteⅠand SiteⅡ), which could bind siroheme and [Fe4S4]. DSRB retained a [Fe4S4] binding site, with an uncomplimentary structure for siroheme binding. There was no conservative box in DSRD. Sequence analysis of DSR will provide a theoretical basis for quantitative detection, metabolic pathway modification through gene engineering, and sulfate reducing bacteria (SRB) suppression.     

Spacecraft formation control strategy on Sun-Earth Lissajous orbit

To carry out the deep space exploration tasks near Sun-Earth Libration point L2, the CRTBP dynamic model was built up and the numerical conditional quasi-periodic orbit (Lissajous orbit) was computed near L2. Then, a formation controller was designed with linear matrix inequality to overcome the difficulty of parameter tuning. To meet the demands of formation accuracy and present thruster’s capability, a threshold scheme was adopted for formation control. Finally, some numerical simulations and analysis were completed to demonstrate the feasibility of the proposed control strategy.     

La对CH_4-CO_2重整反应催化剂性能的影响

采用等体积浸渍法制备了Ni/γ-Al2O3和Ni/La2O3-γ-Al2O3系列催化剂,通过固定床反应、热重分析等方法,考察了催化剂的性能。结果表明：Ni质量分数为10%的Ni/γ-Al2O3催化剂具有较高的活性;稀土元素La的加入,提高了催化剂的抗积炭性能;在相同的反应条件下,10%Ni/3%La2O3-γ-Al2O3催化剂的积炭量比10%Ni/γ-Al2O3催化剂积炭量降低了40%,稳定性大大提高。以Ni/La2O3-γ-Al2O3催化剂中Ni质量分数10%,并且La质量分数3%为最佳,实验条件下制得的合成气CO/H2接近1/1。     

论会计实验教学体系构建

本文从会计实验教学改革实际,对会计实验教学各方面进行了深入研究,提出了会计本科实验教学体系应建立科学的实验教学标准,应该是全方位、一体化的应用型与研究探索型相结合实验教学体系,通过建立新型会计实验室,加强实验教学仿真性,通过加强教材与教师队伍的建设,健全会计实验教学体系。     

掺蒸汽加热工艺装置控制系统设计

采用原油处理站现有锅炉提供的蒸汽,进行掺蒸汽直接加热稠油处理的新工艺,整个流程掺蒸汽量的大小采用可编程控制器（PLC）控制系统发出指令自动控制,可使蒸汽与原油达到最佳混合,同时降低成本,提高可靠性和安全性。本文介绍该装置的可编程控制器（PLC）控制系统I/O接线图、梯形图。     

星际软着陆机动能力评估方法研究

针对软着陆过程中自主选取安全着陆点的需要,研究了探测器机动能力的评估方法.首先根据软着陆制导律,建立加速度模型积分结果与剩余燃料可生成速度增量之间的数学关系,推导出探测器机动能力的数值计算方法;其次,将软着陆过程中抵消重力作用与位置机动看作两个独立的过程,并假设位置机动过程为理想两脉冲机动,推导出解析的软着陆机动能力表达式;最后,通过数值仿真表明两种分析方法能够得到相近的结果,解析的机动能力分析方法可以实时的对探测器可能着陆区域进行预测,能够为探测器自主的选定着陆点提供重要依据.     

复合絮凝剂-SBR工艺处理市政污水中试研究

采用复合絮凝剂-序批式活性污泥法(SBR)工艺对北京某污水厂初沉池出水进行中试处理,研究了该工艺的出水水质和污泥性能。结果表明,在水处理量为0.75 m~3/h、复合絮凝剂投加量为20μL/L的情况下,出水COD和TP、NH_4~+-N、TN的质量浓度平均分别为20.5 mg/L和0.3、0.5、14 mg/L,均可达到GB 18918-2002一级A标准。在长期投加复合絮凝剂的条件下,污泥沉降性能提升明显,胞外聚合物凝聚性变强,整体性能已十分接近好氧颗粒污泥。复合絮凝剂-SBR工艺继承在好氧颗粒污泥技术大部分优点的同时,更能保证污泥颗粒和出水水质稳定,可用于污水处理厂提标改造。     

计算机应用课程理实一体化教学法研究

针对传统教学法的弊端,文章介绍了理实一体化教学法的概念、特点,结合计算机课程,提出了使用此方法进行教学时应把握的要点,在操作性较强的课程教学中采用这种方法将会收到意想不到的效果。     

褐煤成型的研究

由于褐煤具有含水率高，灰份大，易风化，发热值低等特点，使得成型难度很大．本文重点研究水份粒度、添加剂、成型压力等对褐煤成型的影响．最佳条件：粒度＜１ｍｍ，水份１４～１６％，压力＞５０Ｔｆ，添加剂１０～２０％．