The reactions of 18 crown 6 with each of K 2(M=Zn, Hg; mnt=1,2 dicyanoethene 1,2 dithiolate, C 2S 2(CN) 2- 2) were studied and novel complexes [K(18 C 6)] 2[Zn(mnt) 2](1) and [K(18 C 6)] 2[Hg(mnt)...The reactions of 18 crown 6 with each of K 2(M=Zn, Hg; mnt=1,2 dicyanoethene 1,2 dithiolate, C 2S 2(CN) 2- 2) were studied and novel complexes [K(18 C 6)] 2[Zn(mnt) 2](1) and [K(18 C 6)] 2[Hg(mnt) 2](2) were characterized by elemental analysis, IR spectrum and X ray diffraction analysis. Complex 1 displays a one dimensional chain of [K(18 C 6)] 2[Zn(mnt) 2] bridged by K O interactions between adjacent [K(18 C 6)] + units. Complex 2 is also a one dimensional chain of [K(18 C 6)] 2[Hg(mnt) 2] bridged by K...S weak interactions between adjacent [K(18 C 6)] + and [Hg(mnt) 2] 2- .展开更多
In the process of generating assembly dimension chain automatically, there are many problems such as complex assembly relationship, variety of constraints of components and complex dimension and tolerance relations of...In the process of generating assembly dimension chain automatically, there are many problems such as complex assembly relationship, variety of constraints of components and complex dimension and tolerance relations of components. These problems lead to many difficulties in search process and need lots of man-machine interaction. Because of these difficulties, this paper presents a method of automatic generation of assembly dimension chain based on tolerance cell. This method is realized through obtaining assembly tolerance cell and part tolerance cell first. These two types of tolerance cell are extracted and expressed in the form of linked list structure in computer further. Then assembly dimension chain is searched automatically based on obtained tolerance cell, and the correct assembly dimension chain is extracted finally. A system of generating assembly dimension chain automatically has been developed based on DELMIA and successfully deployed in aircraft assembly simulation in the engineerine practice.展开更多
The normal contact force determines the behavior of a particle system.To investigate the normal contact force in a one‐dimensional sphere chain subjected to impact load,by comparing the simulation results of the exis...The normal contact force determines the behavior of a particle system.To investigate the normal contact force in a one‐dimensional sphere chain subjected to impact load,by comparing the simulation results of the existing typical normal contact force models embedded in the discrete element program,an improved normal contact force model was proposed in this paper.The improved model con-sists of two parts:the Cundall model for loading and the Daniel model for unloading.Moreover,a systematic test was designed to verify the accuracy and applicability of the improved model.The results showed that the calculated contact force curves agree well with the experimental results.Furthermore,the improved model is implemented in the solution algorithm without need for complex numerical methods and parameters fitting,leading to more efficient simulations.展开更多
文摘The reactions of 18 crown 6 with each of K 2(M=Zn, Hg; mnt=1,2 dicyanoethene 1,2 dithiolate, C 2S 2(CN) 2- 2) were studied and novel complexes [K(18 C 6)] 2[Zn(mnt) 2](1) and [K(18 C 6)] 2[Hg(mnt) 2](2) were characterized by elemental analysis, IR spectrum and X ray diffraction analysis. Complex 1 displays a one dimensional chain of [K(18 C 6)] 2[Zn(mnt) 2] bridged by K O interactions between adjacent [K(18 C 6)] + units. Complex 2 is also a one dimensional chain of [K(18 C 6)] 2[Hg(mnt) 2] bridged by K...S weak interactions between adjacent [K(18 C 6)] + and [Hg(mnt) 2] 2- .
文摘In the process of generating assembly dimension chain automatically, there are many problems such as complex assembly relationship, variety of constraints of components and complex dimension and tolerance relations of components. These problems lead to many difficulties in search process and need lots of man-machine interaction. Because of these difficulties, this paper presents a method of automatic generation of assembly dimension chain based on tolerance cell. This method is realized through obtaining assembly tolerance cell and part tolerance cell first. These two types of tolerance cell are extracted and expressed in the form of linked list structure in computer further. Then assembly dimension chain is searched automatically based on obtained tolerance cell, and the correct assembly dimension chain is extracted finally. A system of generating assembly dimension chain automatically has been developed based on DELMIA and successfully deployed in aircraft assembly simulation in the engineerine practice.
基金National Natural Science Foundation of China,Grant/Award Numbers:51874118,51778211supported by the National Natural Science Foundation of China(Nos.51874118,51778211).
文摘The normal contact force determines the behavior of a particle system.To investigate the normal contact force in a one‐dimensional sphere chain subjected to impact load,by comparing the simulation results of the existing typical normal contact force models embedded in the discrete element program,an improved normal contact force model was proposed in this paper.The improved model con-sists of two parts:the Cundall model for loading and the Daniel model for unloading.Moreover,a systematic test was designed to verify the accuracy and applicability of the improved model.The results showed that the calculated contact force curves agree well with the experimental results.Furthermore,the improved model is implemented in the solution algorithm without need for complex numerical methods and parameters fitting,leading to more efficient simulations.
