Solubility-Boosted Molecular Sieving-Based Separation for Purification of Acetylene in Core–Shell IL@MOF Composites

Considering the small amount of CO₂ as a contaminant in industrial gas mixtures, developing CO₂-selective adsorbents exhibit advantages in directly obtaining pure C₂H₂ in one-step to reduce the energy consumption. However, it is still a great challenge due to the essential molecular feature of C₂H₂, including the triple bond and high polarizability. Herein, a simple but effective CO₂-facilitated transport strategy is presented to realize the overwhelming adsorption of CO₂ over C₂H₂ by constructing core–shell composite structures using ionic liquid (IL) and metal-organic framework (MOF). With the aid of excellent solubility of CO₂ in IL and almost total exclusion of C₂H₂, the obtained materials boost molecular sieving-based separation of CO₂/C₂H₂. Density functional theory calculations combining molecular dynamic simulations revealed the solution-diffusion mechanism for CO₂, which is rarely reported in solid adsorbents. Ideal adsorbed solution theory selectivity for CO₂/C₂H₂ with 1/1 and 1/3 volume ratios can reach over 10⁴ and 4000 at 100 kPa with a high CO₂ uptake of 40.3 cm³ g⁻¹, superior to those of the reported materials so far. More importantly, this solution-based separation strategy can avoid the difficulty for precise control of the regulation of adsorbent structure, which may be beneficial to practical production.     

异质结构中载流子输运的二维自洽全能带系综蒙特卡罗模拟

本文展示了一个用于异质结构模拟的二维全能带系综蒙特卡罗模拟器,它通过自洽求解二维泊松和波尔兹曼方程,同时处理了载流子在两种不同半导体材料以及其其界面处的输运。本文给出了该蒙特卡罗模拟器的内部结构,包括通过赝势方法计算得到全能带结构、包含的不同散射机制和对载流子在两种不同半导体材料边界输运的适当处理。作为验证,我们对两种不同掺杂的Si-Ge异质结—p-p同型异质结和n-p异型异质结进行了模拟,给出了其I-V特性以及电势和载流子浓度分布,这些结果验证了我们的异质器件蒙特卡罗模拟器的有效性。     

碳纳米管的分子动力学模拟

碳纳米管的纳米级尺寸在很大程度上限制了人们对它的了解、测试与观测，严重地影响了它的发展和应用。因此，必须有简单可行的方法来合理计算、测量碳纳米管的各种特性，计算机模拟无疑是研究这种特殊材料的极佳方法。采用分子动力学模拟的方法，来模拟碳纳米管的物理特性。首先模拟了碳纳米管的热稳定性，发现单壁开口碳纳米管的热稳定性将随着管径的增大而变差，同时开口碳纳米管在真空中保持稳定的极限温度在3000K左右。接着模拟了两根开口碳纳米管的碰撞过程以及成键情况，模拟结果表明在开口端的碳原子非常活跃，极易与其它活性原子成键并且形成新的分子结构，这预示了只要使用一些简单的切割和组合就可以用碳纳米管组成纳微机械；最后对碳纳米管轴承结构的研究显示出碳纳米管之间仅仅存在很小的范德华力，这种独特的特性预示着碳纳米管构成的纳微机械会有卓越的机械特性。     

激光诱导1,2—二氯乙烷链式反应生成氯乙烯...

用计算机模拟了紫外激光诱导1,2-二氯乙烷链式反应生成氯乙烯的动力学过程。给出终态产物和中间产物的时间演化以及各种参数对转变率及量子产率的影响。     

Si和Si-Ge结中不同带带隧穿模型的对比研究

We compared several different band-to-band tunneling(BTBT) models with both Sentaurus and the two-dimensional full-band Monte Carlo simulator in Si homo-junctions and Si-Ge hetero-junctions. It was shown that in Si homo-junctions, different models could achieve similar results. However, in the Si-Ge hetero-junctions, there were significant differences among these models at high reverse biases(over 2 V). Compared to the nonlocal model, the local models in Sentaurus underrated the BTBT rate distinctly, and the Monte Carlo method was shown to give a better approximation. Additionally, it was found that in the Si region near the interface of the Si-Ge hetero-junctions, the direct tunneling rates increased largely due to the interaction of the band structures of Si and Ge.     

1-丁基-3-甲基咪唑离子液体在超级电容器中的应用

两步法合成了1-丁基-3-甲基咪唑三氟乙酸盐(BMI-CF3CO2)、1-丁基-3-甲基咪唑六氟磷酸盐(BMI-PF6)及1-丁基-3-甲基咪唑四氟硼酸盐(BMI-BF4)三种离子液体,研究了这三种离子液体所制超级电容器的电化学性能。结果表明:BMI-CF3CO2在电化学稳定性及充放电效率等方面优于BMI-PF6和BMI-BF4;BMI-CF3CO2离子液体电解液电势窗口达到4.0V,所制备的超级电容器在3.6V电压下循环寿命超过1000次。