Grand canonical Monte Carlo simulation for hydrogen uptakes based on nanoporous NaBH4

A new hydrogen storage route of 3D nanoporous sodium borohydride (NPSB) generated by removing special atoms is proposed in this work. Three different size pores of NPSB-1 (7), NPSB-2 (10) and NPSB-3 (14) are presented, and the hydrogen storage capacities of these NPSBs are simulated by employing a grand canonical Monte Carlo (GCMC) procedure for a temperature range of 77-298 K and a pressure range of 0.1-100 bar. The effects of pore diameter, temperature and pressure on the hydrogen adsorption have been examined. The results show that the adsorption of hydrogen decreases and increases with increasing temperature and hydrogen pressure, respectively. It also reflects that the hydrogen adsorption capacities at higher pressures are dependent on pore diameter, while independent of pore diameter at lower pressures.     

尖晶石型LiMn2O4的低温制备

锂锰氧化物;溶胶凝胶法;尖晶石型LiMn2O4的低温制备     

宏观放电参数对快原子态氮(N+,Nf)的影响

采用氮直流辉光放电等离子体中快电子和重粒子(N₂⁺,N⁺,N_f)混合的蒙特卡罗方法,模拟研究了快原子态粒子(N⁺,N_f)的产生率及轰击阴极的能量分布随宏观放电参数(P,V)的变化规律.结果表明,存在一最佳放电条件,使阴极壁处粒子(N⁺,N_f)的粒子数密度大且能量高;当电压大于800V时,轰击阴极的活性粒子(N⁺,N_f),主要由N₂⁺-N₂离解过程产生,电压小于300V时,主要由e^--N₂离解过程产生,模拟结果与实验结果相符合.     

一个吡啶二甲酸镉配位聚合物的合成、晶体结构及荧光性质

通过水热方法,采用H3CAM(H3CAM=4-hydroxy-pyridine-2,6-dicarboxylic acid)与Cd(NO3)2.4H2O反应,合成了1个镉配位聚合物[Cd4(HCAM)4(H2O)8]n(1),并对其结构和荧光性质进行了研究。结构分析结果表明该配合物属于单斜晶系,C2/c空间群。四个HCAM2-配体桥联4个镉离子形成了1个四核镉单元。这些孤立的单元通过氢键作用形成了1个三维配位框架。研究表明,该配合物在室温下能发出兰色荧光。     

Conventional processes and membrane technology for carbon dioxide removal from natural gas:A review

Membrane technology is becoming more important for CO 2 separation from natural gas in the new era due to its process simplicity,relative ease of operation and control,compact,and easy to scale up as compared with conventional processes.Conventional processes such as absorption and adsorption for CO 2 separation from natural gas are generally more energy demanding and costly for both operation and maintenance.Polymeric membranes are the current commercial membranes used for CO 2 separation from natural gas.However,polymeric membranes possess drawbacks such as low permeability and selectivity,plasticization at high temperatures,as well as insufficient thermal and chemical stability.The shortcomings of commercial polymeric membranes have motivated researchers to opt for other alternatives,especially inorganic membranes due to their higher thermal stability,good chemical resistance to solvents,high mechanical strength and long lifetime.Surface modifications can be utilized in inorganic membranes to further enhance the selectivity,permeability or catalytic activities of the membrane.This paper is to provide a comprehensive review on gas separation,comparing membrane technology with other conventional methods of recovering CO 2 from natural gas,challenges of current commercial polymeric membranes and inorganic membranes for CO 2 removal and membrane surface modification for improved selectivity.     

新的压电薄膜——Ta2O5

据报道,日本Yasuhiko Nakagawa和Yasuo Gomi用磁控反应直流二极管溅射法将Ta_2O_5,沉积在石英基片上,得到了单晶薄膜,并且首次观察到了这种薄膜的压电现象.用叉指换能器在Ta_2O_5薄膜上成功地激发了声表面波.在Ta_2O_5/熔石英基片上,当薄膜厚度h在hk(=2πh/λ)=1.0时,其机电耦合系数k~2=0.5％,它可与熔石英基片上ZnO薄膜的机电耦合系数相比拟. 利用Ta_2O_5单晶的X射线衍射数据,推断出Ta_2O_5     

TiO2纳米管的力学和电子学性质

基于密度泛函理论研究了纤铁矿和锐钛矿型TiO₂纳米管的原子结构、稳定性、Young模量以及电子能带结构.计算结果显示：在纳米管直径较小时,锐钛矿型TiO₂纳米管的稳定性要好于纤铁矿型纳米管,随着管径的增大,纤铁矿型纳米管变得比锐钛矿型纳米管要更稳定.纤铁矿型TiO₂纳米管具有比锐钛矿型纳米管更大的Young模量,力学性能比较优异.另外,通过对电子能带结构的研究发现,手性对TiO₂纳米管的电子结构影响较大,纤铁矿（0,n）型和锐钛矿（n,0）型纳米管为间接带隙半导体,而纤铁矿（n,0）型和锐钛矿（0,n）型纳米管却具有直接带隙. 关键词： 2纳米管')" href="#">TiO₂纳米管 Young模量 间接带隙 直接带隙     

基于4，8-二氢二呋咱[3，}4-b，e]吡嗪高能材料的设计与筛选

为了寻找高能量密度的材料,本文设计了一系列基于4,8-二氢二呋咱[3,4-b,e]吡嗪的含能材料. 利用密度泛函理论研究了它们结构与性质之间的关系. 结果表明,这些设计化合物的性质受到含能基团和杂环取代基的影响. -N₃含能基团是提高设计化合物生成热的最有效取代官能团,而四唑环/-C(NO₂)₃基团对炸药的爆轰性能有较大贡献. 键解离能分析表明,引入-NHNH₂,-NHNO₂,-CH(NO₂)₃和-C(NO₂)₃基团会显著降低键解离能. 由于化合物A8,B8,C8,D8,E8和F8具有良好的爆轰性能和热稳定性,最终被筛选为潜在的高能密度材料. 此外,还计算了这些筛选化合物的电子结构.     

碱土金属氟卤化物中的Eu3+的荧光光谱特征

本文系统研究了MFX体系中Eu³⁺荧光光谱特征,着重讨论了X^-,M²⁺及杂质缺陷(主要为O^2-)对Eu³⁺发光的影响.