关键词： CO2   Storage   Methane   Sorption kinetics   Adsorbed phase density  

摘要： Evidence from experimental studies related to sorption on nanoporous materials, coals, and most recently on shales suggests that the sorption of gas in these targets is not instantaneous, i.e. the time it takes for the gas to adsorb to its maximum capacity is not negligible. A recent experimental study showed that the sorption in shale rocks is non-instantaneous, i.e. there is a delayed effect in adsorption due to different mechanisms of sorption in different materials of shale, for e.g. in inorganic and organic matter. The current suite of models used to predict sorption in shale (e.g. Langmuir, BET, etc.) assumes an instantaneous equilibrium, which is not justifiable for sorption in shales. Sorption of hydrocarbons and carbon dioxide in shale stratum is a complex mechanism that is affected by micro-scale affinity between the adsorbent-adsorbate, pore-scale heterogeneity of the surface with respect to the pore distribution, and structural heterogeneity of the system. These mull-phenomena effects are mull-scale in nature, and their impact on sorption cannot be predicted using simple models that assume instantaneous equilibrium. A model for reliable prediction of sorption in shales must take into account above discussed effects. This study proposes a mechanistic model for mull-scale sorption dynamics (referred as "MSSD") in shale that accounts for molecular and pore-scale effects, in addition to the continuum-scale effects, by corresponding parameters that are relevant on those scales. Proposed model is validated against three experimental datasets that depict sorption dynamics in shale. The MSSD model is then used to investigate the efficiency of carbon storage in shale by adsorption when it is injected as a binary mixture with methane. The proposed model makes it convenient to study the effects of molecular-scale to continuum-scale parameters on sorption in shale that are otherwise possible only through expensive means of experiments or molecular dynamic simulation

关键词： Global phase portrait   Limit cycle   Grazing bifurcation   Grazing-sliding bifurcation   Discontinuous piecewise differential system  

摘要： The global dynamics of a mechanical system with dry friction is completely analyzed. This mechanical system is a class of discontinuous and transcendental piecewise smooth differential systems. Moreover, it can exhibit rich and complex dynamical phenomena, such as Hopf bifurcation, grazing bifurcation, grazing-sliding bifurcation and bifurcations of limit cycles. Finally, all global phase portraits of the system are presented on the Poincare disc. (C) 2018 Elsevier Inc. All rights reserved.

关键词： 量子光学   量子纠缠   纳米金刚石机械振子   氮空位(NV)色心   负值度  

摘要： 研究了二阶磁梯度诱导的纳米金刚石氮空位(NV)色心耦合机械振子系统中两机械模式与NV色心的纠缠动力学特性,分析了系统相干角、机械模式的衰减率、NV色心的自发衰减率等对纠缠的影响。研究结果表明,选择合适的系统参数可以制备机械模式和NV色心之间的最大纠缠态;相干角对系统的纠缠动力学特性具有重要影响,当耗散存在时,通过控制相干角可以有效调节系统抵抗纠缠衰减的能力;相比于NV色心的自发衰减,机械模式的衰减使系统纠缠更快衰减和消失。

关键词： 构件   刚体   仿真   优化设计  

摘要： 对码垛机详细设计后为了校核各个构件的强度情况,我们在三维模型基础上假设构件皆为刚体,合理设定仿真条件,对整个结构进行了多刚体动力学仿真分析,在分析结果的基础上对设计进行了优化,最终设备的使用效果良好。

关键词： 机械手   动力学仿真   牛顿-欧拉方法  

摘要： 设计了用于危险化工原料在管道运输和反应容器中泄漏修补的移动机械手。该系统由移动平台和固接在其上的五自由度关节机械手构成。采用牛顿-欧拉方法建立该机械手的动力学模型,并考虑了平台运动时在机械手上产生的惯性力对模型的影响。最后使用ADAMS软件对样机模型进行了仿真验证。

关键词： 工程机械   动力系统   机械制造企业   排放标准   标准实施   移动机械   非道路   发动机  

摘要： 在实施“国三”排放标准2年后,根据环保形势的需要,中国非道路移动机械第四阶段排放标准实施紧锣密鼓地提上日程,这对于工程机械制造企业、发动机制造企业以及工程机械用户来说,无疑又是一场大考。

关键词： 玻璃机械和设备   玻璃行业   发展推动力  

摘要： 在我国范围内,玻璃有着非常悠久的历史,功能也随着时代的不断变迁为得到了丰富,并且玻璃在人们的生产和生活中发挥着非常重要的作用。与此同时近些年来随着社会需求的不断增加,玻璃行业得到了很好的发函,基于此,本文主要对玻璃机械和设备将成为玻璃行业发展的推动力进行研究和分析,希望对相关人士有所帮助。

关键词： molecular dynamics   phase separation   polyurethanes   viscoelastic properties  

摘要： To relate the mechanical responses of hard-soft copolymer systems with their microstructures, a coarse-grained molecular dynamics approach is employed, and mechanical properties of both hard and soft domains are calculated. We first investigate the enhancement mechanism of hard domains under tensile and shear loading conditions with pressure. The energy factor that denotes the interaction between hard beads dominates the microphase separation and morphology. Our numerical experiments show that pressure is the most crucial factor in shear-under-pressure tests, with larger pressure leading to higher shearing resistance of the copolymers. The viscoelastic behaviors of hard-soft copolymers are computed from the stress autocorrelation function. The stress relaxation indicates that the soft matrix is in a rubbery state at room temperature while hard domains are "glass-like" and can be viewed as elastic solids in a macroscale model. In addition, local elastic constants of hard domains are computed using the stress-strain fluctuation method with purely local stress and local strain. Those results can be used as inputs for macroscale models for copolymers and can provide guidelines for designing polymeric materials. (c) 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 1552-1566

关键词： 机械设计   MATLAB   曲柄滑块   优化设计  

摘要： 针对目前机械设计类课程偏重理论知识的学习且很难调动学生主观能动性的现实问题,根据课堂教学经验,在分析设计原理与方法课程特点的基础上,提出采用MATLAB软件作为辅助工具进行教学实践。文中还以曲柄滑块机构的平衡优化设计为研究对象,从教学内容、教学方法等方面向学生传授基础理论知识,训练学生的实践能力,提高教学质量。

关键词： 自行车   刹车器   改装   制动力调节系统  

摘要： 此文介绍在前期研究各种刹车器、不同路面、不同坡度下自行车的制动方式的基础上,对自行车V刹制动力调节系统进行改装,使之应用于碟刹类系统的过程。