采用迭加原理和Kachanov提出的简化方法,研究了裂纹间的相互作用机理,分析了不同裂纹布置形式所产生的增强或屏蔽效应,发现当微裂纹沿着或垂直于最大拉应力方向布置时都不产生最大的作用效应,这有别于Ortiz[ASME Journal of Applied Mec...采用迭加原理和Kachanov提出的简化方法,研究了裂纹间的相互作用机理,分析了不同裂纹布置形式所产生的增强或屏蔽效应,发现当微裂纹沿着或垂直于最大拉应力方向布置时都不产生最大的作用效应,这有别于Ortiz[ASME Journal of Applied Mechanics,1987,54(3):54-58]的结论.还探讨了混凝土类材料的微裂纹的产生机制及微裂纹区对主裂纹尖端产生的作用效应,得出微裂纹区对主裂纹是起增强的作用,增强程度随微裂纹密度和微裂纹长度的增大而增大的结论.展开更多
The contact of a rigid body with nominally flat rough surface and an elastic half-space is considered.To solve the contact problem,the Greenwood-Williamson statistical model and the localization principle are used.The...The contact of a rigid body with nominally flat rough surface and an elastic half-space is considered.To solve the contact problem,the Greenwood-Williamson statistical model and the localization principle are used.The developed contact model allows us to investigate the surface approach and the real contact area with taking into account the asperities interaction.It is shown that the mutual influence of asperities changes not only contact characteristics at the macroscale,but also the contact pressure distribution at the microscale.As follows from the results,the inclusion in the contact model of the effect of the mutual influence of asperities is especially significant for studying the real contact area,as well as the contact characteristics at high applied loads.The results calculated according to the proposed approach are in a good agreement with the experimentally observed effects,i.e.,the real contact area saturation and the additional compliance exhaustion.展开更多
The Standard Model of Particle Physics treats four fields—the gravitational, electromagnetic, weak and strong fields. These fields are assumed to converge to a single field at the big bang, but the theory has failed ...The Standard Model of Particle Physics treats four fields—the gravitational, electromagnetic, weak and strong fields. These fields are assumed to converge to a single field at the big bang, but the theory has failed to produce this convergence. Our theory proposes<em> one </em>primordial field and analyzes the evolution of this field. The key assumption is that <em>only</em> the primordial field exists—if any change is to occur, it must be based upon self-interaction, as there is nothing other than the field itself to interact with. This can be formalized as the <em>Principle</em> <em>of </em><em>Self-interaction</em> and the consequences explored. I show that this leads to the linearized Einstein field equations and discuss the key ontological implications of the theory.展开更多
The liquid products of Fischer–Tropsch synthesis with a high content of linearα-olefins can act as valuable raw materials for increasing high added-valueα-olefin production if the challenging separation of long-ch...The liquid products of Fischer–Tropsch synthesis with a high content of linearα-olefins can act as valuable raw materials for increasing high added-valueα-olefin production if the challenging separation of long-chainα-olefin/paraffin is achieved.Adsorption separation is an efficient alternative to energy-intensive distillation.Herein,the selective adsorption behavior and interaction mechanism of liquidα-olefin/paraffin on Mg metal–organic framework(MOF)-74 were investigated using a combination of batch adsorption experiments and molecular simulation techniques.Mg-MOF-74 exhibited 301 and 333 mg/g olefin adsorption capacities for C6 and C8 linearα-olefins in binary olefin/paraffin mixtures,respectively,and was still unsaturated at high olefin concentrations.The adsorption isotherms were analyzed and compared with the simulated results by configurational-bias grand canonical Monte Carlo(CB-GCMC)simulation.The visualized adsorption sites by CB-GCMC simulation indicated that all adsorbates were arranged in hexagonal shapes and preferentially adsorbed by the vertex of the hexagon,where the metal node magnesium is located.The adsorption energies were−1.456 and−0.378 eV for C8 linearα-olefin and paraffin,respectively,calculated by density functional theory simulation based on the visualized adsorption sites.The charge transfer was analyzed,and the contributions of different kinds of interactions to the overall adsorption energy were quantified by principle orbital interaction analysis to further reveal the difference in adsorption energy betweenα-olefin/paraffin and Mg-MOF-74.This work also provides a general means to investigate the liquid adsorption performance and host–guest interactions in the adsorption or catalytic processes of nanoporous materials.展开更多
基于密度泛函理论的第一性原理计算,本文对单层1T-CoI_(2)的原子、电子结构和磁性进行了理论研究.使用广义布洛赫条件结合自旋螺旋方法计算了单层1T-CoI_(2)自旋螺旋的能量色散关系E(q),计算结果表明单层1T-CoI_(2)的基态呈现螺旋反铁磁...基于密度泛函理论的第一性原理计算,本文对单层1T-CoI_(2)的原子、电子结构和磁性进行了理论研究.使用广义布洛赫条件结合自旋螺旋方法计算了单层1T-CoI_(2)自旋螺旋的能量色散关系E(q),计算结果表明单层1T-CoI_(2)的基态呈现螺旋反铁磁,体系中含有键相关的各向异性作用,即Kitaev作用.计算了含有自旋-轨道耦合作用(spin orbital coupling,SOC)和不含有SOC的色散关系,分别将色散关系映射到HeisenbergKitaev模型,成功分解了多近邻海森伯作用参数J、Kitaev作用的K和非对角项Γ.单层1T-CoI_(2)以Heisenberg作用为主导,同时存在着较强的Kitaev相互作用,其中Γ_(1)达到了1.09 meV.可预测Kitaev作用在具有1T结构过渡金属三角格子中具有普遍适用性,表明单层1T-CoI_(2)是Kitaev的备选材料,并且为探索其他二维磁性材料的Kitaev作用奠定了理论基础.展开更多
文摘采用迭加原理和Kachanov提出的简化方法,研究了裂纹间的相互作用机理,分析了不同裂纹布置形式所产生的增强或屏蔽效应,发现当微裂纹沿着或垂直于最大拉应力方向布置时都不产生最大的作用效应,这有别于Ortiz[ASME Journal of Applied Mechanics,1987,54(3):54-58]的结论.还探讨了混凝土类材料的微裂纹的产生机制及微裂纹区对主裂纹尖端产生的作用效应,得出微裂纹区对主裂纹是起增强的作用,增强程度随微裂纹密度和微裂纹长度的增大而增大的结论.
基金supported the Russian Science Foundation(No.22-49-02010).
文摘The contact of a rigid body with nominally flat rough surface and an elastic half-space is considered.To solve the contact problem,the Greenwood-Williamson statistical model and the localization principle are used.The developed contact model allows us to investigate the surface approach and the real contact area with taking into account the asperities interaction.It is shown that the mutual influence of asperities changes not only contact characteristics at the macroscale,but also the contact pressure distribution at the microscale.As follows from the results,the inclusion in the contact model of the effect of the mutual influence of asperities is especially significant for studying the real contact area,as well as the contact characteristics at high applied loads.The results calculated according to the proposed approach are in a good agreement with the experimentally observed effects,i.e.,the real contact area saturation and the additional compliance exhaustion.
文摘The Standard Model of Particle Physics treats four fields—the gravitational, electromagnetic, weak and strong fields. These fields are assumed to converge to a single field at the big bang, but the theory has failed to produce this convergence. Our theory proposes<em> one </em>primordial field and analyzes the evolution of this field. The key assumption is that <em>only</em> the primordial field exists—if any change is to occur, it must be based upon self-interaction, as there is nothing other than the field itself to interact with. This can be formalized as the <em>Principle</em> <em>of </em><em>Self-interaction</em> and the consequences explored. I show that this leads to the linearized Einstein field equations and discuss the key ontological implications of the theory.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.21878169 and 21991102)Key Technologies Research and Development Program of China(No.2019YFA0905100)Tsinghua University Initiative Scientific Research Program(No.2018Z05JZY010).
文摘The liquid products of Fischer–Tropsch synthesis with a high content of linearα-olefins can act as valuable raw materials for increasing high added-valueα-olefin production if the challenging separation of long-chainα-olefin/paraffin is achieved.Adsorption separation is an efficient alternative to energy-intensive distillation.Herein,the selective adsorption behavior and interaction mechanism of liquidα-olefin/paraffin on Mg metal–organic framework(MOF)-74 were investigated using a combination of batch adsorption experiments and molecular simulation techniques.Mg-MOF-74 exhibited 301 and 333 mg/g olefin adsorption capacities for C6 and C8 linearα-olefins in binary olefin/paraffin mixtures,respectively,and was still unsaturated at high olefin concentrations.The adsorption isotherms were analyzed and compared with the simulated results by configurational-bias grand canonical Monte Carlo(CB-GCMC)simulation.The visualized adsorption sites by CB-GCMC simulation indicated that all adsorbates were arranged in hexagonal shapes and preferentially adsorbed by the vertex of the hexagon,where the metal node magnesium is located.The adsorption energies were−1.456 and−0.378 eV for C8 linearα-olefin and paraffin,respectively,calculated by density functional theory simulation based on the visualized adsorption sites.The charge transfer was analyzed,and the contributions of different kinds of interactions to the overall adsorption energy were quantified by principle orbital interaction analysis to further reveal the difference in adsorption energy betweenα-olefin/paraffin and Mg-MOF-74.This work also provides a general means to investigate the liquid adsorption performance and host–guest interactions in the adsorption or catalytic processes of nanoporous materials.
文摘基于密度泛函理论的第一性原理计算,本文对单层1T-CoI_(2)的原子、电子结构和磁性进行了理论研究.使用广义布洛赫条件结合自旋螺旋方法计算了单层1T-CoI_(2)自旋螺旋的能量色散关系E(q),计算结果表明单层1T-CoI_(2)的基态呈现螺旋反铁磁,体系中含有键相关的各向异性作用,即Kitaev作用.计算了含有自旋-轨道耦合作用(spin orbital coupling,SOC)和不含有SOC的色散关系,分别将色散关系映射到HeisenbergKitaev模型,成功分解了多近邻海森伯作用参数J、Kitaev作用的K和非对角项Γ.单层1T-CoI_(2)以Heisenberg作用为主导,同时存在着较强的Kitaev相互作用,其中Γ_(1)达到了1.09 meV.可预测Kitaev作用在具有1T结构过渡金属三角格子中具有普遍适用性,表明单层1T-CoI_(2)是Kitaev的备选材料,并且为探索其他二维磁性材料的Kitaev作用奠定了理论基础.
