Simulation and analysis of asteroid force closure anchoring performance based on discrete element method

Asteroid exploration is significant for studying the origin of the solar system,establishing planetary defenses,and alleviating the resource crisis of the Earth.Asteroid anchoring is the basis of in-situ exploration and resource development and utilization.Therefore,the performance of asteroid force-closure anchoring is investigated using the discrete element method.The micro parameters of the simulated materials are calibrated with angle of repose and uniaxial compression experiments,based on which the regional modeling method is adopted to establish the anchoring discrete element model.Asteroid anchoring experiments are conducted on a self-developed microgravity simulation platform to verify the accuracy of the simulation model.The asteroid anchoring simulations are performed to investigate the influence of external force on the anchoring performance.The analysis of anchoring force varying with time and the interaction between the anchor and regolith particles reveals the influence mechanism of external force direction on the anchoring performance.The external force direction affects the critical anchoring force by influencing the failure of the force-closure structure.The comprehensive analysis of simulation results clarifies the variation of the critical anchoring force with the external forces.Finally,a stable anchoring region is established,beneficial for asteroid anchoring device design.

咪唑类离子液体高效吸收二氯甲烷（英文）

合成了一系列常规离子液体1-丁基-3-甲基咪唑四氟硼酸盐([Bmim][BF4])、1-丁基-3-甲基咪唑六氟磷酸盐([Bmim][PF6])、1-丁基-3-甲基咪唑双三氟甲磺酰亚胺盐([Bmim][NTf2])、1-丁基-3-甲基咪唑双氰胺盐([Bmim][DCA])、1-丁基-3-甲基咪唑硫氰酸盐([Bmim][SCN])、1-乙基-3-甲基咪唑硫氰酸盐([Emim][SCN])和N-丁基吡啶硫氰酸盐([BPy][SCN]),用智能重量分析仪(IGA)测定不同温度和分压下离子液体吸收二氯甲烷(DCM)的容量。结果表明,[Bmim][SCN]具有最高的二氯甲烷吸收容量(1.46 g/g, 303.15 K, 60 kPa),5次循环后吸收能力无明显下降,[Bmim][SCN]基本可完全再生,能循环使用。量化计算结果表明[SCN]-可与二氯甲烷形成氢键,增强其对二氯甲烷的吸收能力。

Regulating sulfur removal efficiency of fuels by Lewis acidity of ionic liquids

当环境污染严重增加，开发燃料的一个新深 desulfurization 过程是迫切的。在这个工作，一系列路易斯酸的离子的液体(IL )[C 43 MPy ] Cl/nZnCl 2(n=1， 1.5， 2， 3 ) 在抽取和燃料的催化氧化 desulfurization (ECOD ) 被综合并且使用。IL 的吊楔酸味的效果， H 2 包括 dibenzothiophene (DBT ) 的 O 2/sulfur, 温度，和不同底层， benzothiophene (BT ) 和 thiophene (TS ) ，在硫上，移动被调查。结果显示了那[C 43 MPy ]Cl/3 ZnCl 2 在 323 K 的条件下面介绍了模型油的近的 100% DBT 移动， H 2 O 2/DBT 臼齿的比率 6:1。为 DBT ， BT 和 TS 由的移动的动力学[ C 4 3 MPy ]Cl/ 3 ZnCl 2-H2在 323 K 的 O 2系统为 DBT 与 1.1348 ， 0.2226 和 0.0609 h -1,和计算明显的激活精力的明显的率常数是一阶的， BT 和 TS 分别地是从 298～308 K 的 61.13 ， 60.66 ，和 68.14 kJ/mol 。在六个周期以后再生[CC 43 MPy ]Cl/3 硫移动有的 ZnCl 2, 细微减少。[CC 43 MPy ]Cl/3 ZnCl 2 在最佳的条件下面显示出好 desulfurization 表演。