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Dynamically modulated synthesis of hollow metal-organic frameworks for selective hydrogenation reactions 被引量:1
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作者 Liyun Xiao Chuanqi Cheng +7 位作者 Zhixi Li Chaoyang Zheng Jing Du Meina Song Yue Wan Shaopeng Li Guo Jun Meiting Zhao 《Nano Research》 SCIE EI CSCD 2023年第8期11334-11341,共8页
Hollow metal-organic frameworks(MOFs)have attracted increasing attention in the field of catalysis in recent years due to their unique cavity structure with fast mass-diffusion rates and easily accessible active sites... Hollow metal-organic frameworks(MOFs)have attracted increasing attention in the field of catalysis in recent years due to their unique cavity structure with fast mass-diffusion rates and easily accessible active sites.Here,we report the use of dynamic modulators,which are formed by the in-situ imine condensation reaction of 4-aminobenzoic acid and 4-formylbenzoic acid,to regulate the growth of MOFs to synthesize well-defined hollow thioether functionalized UiO-67(denoted as H-UiO-67-S)single crystals.After supporting Pd nanoparticles,the designed catalysts Pd@H-UiO-67-S show excellent conversion(>99.9%),selectivity(>99.9%),and stability(10 cycles)in the selective hydrogenation of nitrobenzenes with other reducible groups.Density functional theory calculations and the experimental results reveal that Pd nanoparticles not only selectively adsorb the nitro-groups on nitrobenzene,but also restrict the adsorption of the aniline product,due to the interaction of thioether with Pd in the confined pores of H-UiO-67-S,finally result in a significant increase in selectivity of nitro-hydrogenation. 展开更多
关键词 hollow structure metal-organic frameworks(MOFs) dynamically modulated synthesis selective hydrogenation NITROBENZENE
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An Improved CFD-synthesis Method for Predicting Inlet Dynamic Distortion 被引量:1
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作者 Zhang Lifen Liu Zhenxia +1 位作者 Qu Jiyun Wang Xiaofeng 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2009年第5期467-473,共7页
This article presents an improved computational fluid dynamics (CFD)-synthesis method to predict dynamic distortion. A steady-state flow field is derived from a CFD solution, through which are acquired total pressur... This article presents an improved computational fluid dynamics (CFD)-synthesis method to predict dynamic distortion. A steady-state flow field is derived from a CFD solution, through which are acquired total pressure, density, turbulence kinetic energy and others in steady-state at an aerodynamic interface plane (AIP). Back-propagation artificial neural network (BP ANN) is used to find out the relationship between the measured flight turbulence and the CFD-computed turbulence parameters. The dynamic pressure is obtained by incorporating CFD-found total steady-state pressure with fluctuating pressure. Finally, the dynamic distortion is predicted by means of the synthesized dynamic pressure. The fairly good agreement between the computed inlet surface pressure and the flight test data bears out the reliability of CFD solution used in this article. To validate the proposed method, six sets of flight test data are used and the results show that the predicted dynamic distortion is well in line with the distortion displayed in flight tests. An examination of the traditional method is also accomplished and the comparison also shows that the proposed method is superior to the traditional one in higher consistency with flight test data. 展开更多
关键词 computational fluid dynamics dynamic pressure synthesis turbulence correlation back-propagation artificial neural network dynamic distortion
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Scalable Ambient Pressure Synthesis of Covalent Organic Frameworks and Their Colorimetric Nanocomposites through Dynamic Imine Exchange Reactions 被引量:4
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作者 Wei Zhao Jia Qiao +1 位作者 Tian-Li Ning Xi-Kui Liu 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2018年第1期1-1,2-7,共7页
A novel scale-up ambient pressure synthetic strategy for the preparation of imine-based covalent organic frameworks(COFs) was proposed through dynamic imine exchange reaction mechanism. The obtained COFs exhibited g... A novel scale-up ambient pressure synthetic strategy for the preparation of imine-based covalent organic frameworks(COFs) was proposed through dynamic imine exchange reaction mechanism. The obtained COFs exhibited good crystallinity and much higher porosity comparable to their solvothermally synthesized counterparts. Moreover, under ambient pressure, the COF nanofibers could readily grow on the surface of polyimide films, and the resulted nanocomposite film showed an interesting colorimetric acid-responsive behavior. 展开更多
关键词 Covalent organic frameworks(COFs) dynamic imine exchange Ambient pressure synthesis
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An efficient formulation based on the Lagrangian method for contact–impact analysis of flexible multi-body system 被引量:7
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作者 Peng Chen Jin-Yang Liu Jia-Zhen Hong 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2016年第2期326-334,共9页
In this paper,an efficien formulation based on the Lagrangian method is presented to investigate the contact–impact problems of f exible multi-body systems.Generally,the penalty method and the Hertz contact law are t... In this paper,an efficien formulation based on the Lagrangian method is presented to investigate the contact–impact problems of f exible multi-body systems.Generally,the penalty method and the Hertz contact law are the most commonly used methods in engineering applications.However,these methods are highly dependent on various non-physical parameters,which have great effects on the simulation results.Moreover,a tremendous number of degrees of freedom in the contact–impact problems will influenc thenumericalefficien ysignificantl.Withtheconsideration of these two problems,a formulation combining the component mode synthesis method and the Lagrangian method is presented to investigate the contact–impact problems in fl xible multi-body system numerically.Meanwhile,the finit element meshing laws of the contact bodies will be studied preliminarily.A numerical example with experimental verificatio will certify the reliability of the presented formulationincontact–impactanalysis.Furthermore,aseries of numerical investigations explain how great the influenc of the finit element meshing has on the simulation results.Finally the limitations of the element size in different regions are summarized to satisfy both the accuracy and efficien y. 展开更多
关键词 Multi-body dynamics Contact–impact analysis Lagrangian method Component mode synthesis
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ELECTRON MICROSCOPIC AUTORADIOGRAPHIC STUDIES ON DYNAMICS AND LOCATION OF DNA SYNTHESIS OF DUCK PLAGUE VIRUS
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作者 翟中和 丁明孝 《Science China Chemistry》 SCIE EI CAS 1982年第10期1052-1060,共9页
Electron microscopic autoradiographic studies on the dynamics and location of DNAsynthesis by means of incorporation of ~8H-thymidine during the replication of duck plaguevirus (DPV) revealed that the duration of DNA ... Electron microscopic autoradiographic studies on the dynamics and location of DNAsynthesis by means of incorporation of ~8H-thymidine during the replication of duck plaguevirus (DPV) revealed that the duration of DNA synthesis of DPV was rather long. The repli-cation of viral DNA occurred simultaneously with the assembly procedure of nucleocapsids, thematuration and release of viruses. DNA synthesis of DPV occurred in the matrix with lowerelectron density in the nucleus. The replicated viral DNA accumulated in the viroplast With highelectron density where the assembly of nucleocapsids occurred. The viroplast with high electrondensity was not the region of viral DNA synthesis. 展开更多
关键词 ELECTRON MICROSCOPIC AUTORADIOGRAPHIC STUDIES ON dynamicS AND LOCATION OF DNA synthesis OF DUCK PLAGUE VIRUS DNA
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A Single-legged Robot Inspired by the Jumping Mechanism of Click Beetles and Its Hopping Dynamics Analysis 被引量:6
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作者 Gang Chen Jiajun Tu +1 位作者 Xiaocong Ti Huosheng Hu 《Journal of Bionic Engineering》 SCIE EI CSCD 2020年第6期1109-1125,共17页
The click beetle can jump up with a hinge when it is on the dorsal side.This jumping mechanism is simple and suitable as an inspiration for designing a simple,small,and reliable hopping robot.We report a single-legged... The click beetle can jump up with a hinge when it is on the dorsal side.This jumping mechanism is simple and suitable as an inspiration for designing a simple,small,and reliable hopping robot.We report a single-legged robot inspired by the jumping mechanism of click beetles.It is 85 mm high,60 mm long,and 41 mm wide,and weighs about 49 g.The robot has good hopping performance that the hopping height is about 4 times-4.3 times of its body height.It is capable for rescue missions that require to enter enclosed spaces through cracks and narrow channels.In addition,hopping dynamics of the robot is important to understand its jumping mechanism and improve the robot’s hopping performance.But existing dynamic study does not complete the analysis including all stages in the hopping which are pre-hopping,take-off,and air-flying.We propose the decomposition method to study dynamics of the three stages separately,and synthesize them with related parameters.The dynamic synthesis of multi-motion states in a hopping cycle of the single-legged hopping robot is implemented.The hopping performance and dynamic synthesis theory of the robot are verified by simulations and experiments.Our study helps lay the foundation for design and hopping control of simple hopping robot systems. 展开更多
关键词 single-legged hopping robots hopping cycle dynamics synthesis multi-motion states jumping mechanism imitaion of click beetles
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FORMATION OF MICRO-POROUS SPHERICAL PARTICLES OF CALCIUM SILICATE(XONOTLITE) IN DYNAMIC HYDROTHERMAL PROCESS 被引量:6
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作者 MaoqiangLi HongxunLiang 《China Particuology》 SCIE EI CAS CSCD 2004年第3期124-127,共4页
Stirring during hydrothermal synthesis plays an important role in the formation of porous spherical xonotlite particles. The size of spherical particles formed during dynamic hydrothermal process is related to the siz... Stirring during hydrothermal synthesis plays an important role in the formation of porous spherical xonotlite particles. The size of spherical particles formed during dynamic hydrothermal process is related to the size of minimum vortices in the reaction slurry, which is determined by stirring speed. The kinetics of growth of xonotlite particles is de-termined by measuring the apparent viscosity of the reactant slurry at various reaction time and reaction temperatures. It is found that the growth of particles follows the contracting-volume equation, and the activation energies for nucleation and growth are 104 and 123 kJ.mol-1, respectively. 展开更多
关键词 porous particle XONOTLITE dynamic hydrothermal synthesis
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