Internal components play a crucial role in the synthesis of organic silicon monomer in gas-solid fluidized bed reactors (FBRs). Finger-tube (F-tube) and U-tube components are commonly utilized to control the temperatu...Internal components play a crucial role in the synthesis of organic silicon monomer in gas-solid fluidized bed reactors (FBRs). Finger-tube (F-tube) and U-tube components are commonly utilized to control the temperature and ensure its homogeneity in FBRs, thereby guaranteeing a high selectivity of the target product. The main objective of this work is to better understand the influence of F-tube and U-tube on the hydrodynamics in FBRs. Computational fluid dynamics (CFD) combined with the particle image velocimetry (PIV) technique were employed to explore the flow characteristics. The numerical data were validated against the particle velocity using an image processing technique. The results revealed that the F-tube increases the bed voidage by 3.2% and reduces the pressure drop by 13.0%. While the U-tube increases the bed voidage by 2.1% and reduces the pressure drop by 11.2%. These internals improve fluidization by ensuring even particle distribution and enhancing intra-particle circulation compared to reactors without internals.展开更多
Design of internal combustion engine (ICE) components is one of the earliest and also the most active areas in which computer aided modeling techniques are applied. Computer aided modeling techniques could provide req...Design of internal combustion engine (ICE) components is one of the earliest and also the most active areas in which computer aided modeling techniques are applied. Computer aided modeling techniques could provide requisite information for follow up designing segments such as structural analysis, design of technological process and manufacturing etc, and thereby lead to the reduction of product design period and the quality and reliability improvement of ICE components. So the developing situations of ICE components' 2 D drafting, 3 D modeling of ICE, overall CAD of ICE as well as component design expert system etc. are surveyed, which are the typical applications of computer aided modeling techniques in ICE component design process, and some existent problems and tasks are pointed out so as to make some references for the further research work.展开更多
In this paper, a design of a miniature antenna for biomedical implant applications is presented. The proposed structure consists of a printed antenna designed to cover all frequency bands below 1 GHz and is dedicated ...In this paper, a design of a miniature antenna for biomedical implant applications is presented. The proposed structure consists of a printed antenna designed to cover all frequency bands below 1 GHz and is dedicated to biomedical applications with good matching, omnidirectional radiation, and a maximum realized gain of −26.7 dBi. It offers two bandwidths of 270 MHz and 762 MHz respectively. A Phantom model of the elliptical cylinder of 180 × 100 × 50 mm3 was used to simulate the electromagnetic radiation inside the human body. The tissue considered is equivalent to a muscle with a relative permittivity of 57 and a conductivity equal to 0.79 S/m. We also studied the antenna behavior when close to the internal electronic components. The simulation showed that the antenna remains robust in such an environment. Finally, the Specific Absorption Rate of the muscle was evaluated when the antenna was fed with 1 V. The evaluation proved that the calculated value of 0.48 W/Kg is well below the limit value imposed by the International Commission on Non-Ionizing Radiation Protection.展开更多
Purpose–Under different ground motion excitation modes,the spatial coupling effect of seismic response for the arch bridge with thrust,seismic weak parts and the internal force components of the control section of ma...Purpose–Under different ground motion excitation modes,the spatial coupling effect of seismic response for the arch bridge with thrust,seismic weak parts and the internal force components of the control section of main arch ribs are analyzed.Design/methodology/approach–Taking a 490 m deck type railway steel truss arch bridge as the background,the dynamic calculation model of the whole bridge was established by SAP2000 software.The seismic response analyses under one-,two-and three-dimension(1D,2D and 3D)uniform ground motion excitations were carried out.Findings–For the steel truss arch bridge composed of multiple arch ribs,any single direction ground motion excitation will cause large axial force in the chord of arch rib.The axial force caused by transverse and vertical ground motion excitation in the chord of arch crown area is 1.4–3.6 times of the corresponding axial force under longitudinal seismic excitation.The in-plane bending moment caused by the lower chord at the vault is 4.2–5.5 times of the corresponding bending moment under the longitudinal seismic excitation.For the bottom chord of arch rib,the arch foot is the weak part of earthquake resistance,but for the upper chord of arch rib,the arch foot,arch crown and the intersection of column and upper chord can all be the potential earthquake-resistant weak parts.The normal stress of the bottom chord of the arch rib under multidimensional excitation is mainly caused by the axial force,but the normal stress of the upper chord of the arch rib is caused by the axial force,in-plane and out of plane bending moment.Originality/value–The research provides specific suggestions for ground motion excitation mode and also provides reference information for the earthquake-resistant weak part and seismic design of long-span deck type railway steel truss arch bridges.展开更多
基金supported by Major Scientific and Technological Innovation Project of Shandong Province(grant No.2021ZDSYS13)Natural Science Foundation of Shandong Province(grant No.ZR2021MB135)Natural Science Foundation of Shandong Province(grant No.ZR2021ME224).
文摘Internal components play a crucial role in the synthesis of organic silicon monomer in gas-solid fluidized bed reactors (FBRs). Finger-tube (F-tube) and U-tube components are commonly utilized to control the temperature and ensure its homogeneity in FBRs, thereby guaranteeing a high selectivity of the target product. The main objective of this work is to better understand the influence of F-tube and U-tube on the hydrodynamics in FBRs. Computational fluid dynamics (CFD) combined with the particle image velocimetry (PIV) technique were employed to explore the flow characteristics. The numerical data were validated against the particle velocity using an image processing technique. The results revealed that the F-tube increases the bed voidage by 3.2% and reduces the pressure drop by 13.0%. While the U-tube increases the bed voidage by 2.1% and reduces the pressure drop by 11.2%. These internals improve fluidization by ensuring even particle distribution and enhancing intra-particle circulation compared to reactors without internals.
文摘Design of internal combustion engine (ICE) components is one of the earliest and also the most active areas in which computer aided modeling techniques are applied. Computer aided modeling techniques could provide requisite information for follow up designing segments such as structural analysis, design of technological process and manufacturing etc, and thereby lead to the reduction of product design period and the quality and reliability improvement of ICE components. So the developing situations of ICE components' 2 D drafting, 3 D modeling of ICE, overall CAD of ICE as well as component design expert system etc. are surveyed, which are the typical applications of computer aided modeling techniques in ICE component design process, and some existent problems and tasks are pointed out so as to make some references for the further research work.
文摘In this paper, a design of a miniature antenna for biomedical implant applications is presented. The proposed structure consists of a printed antenna designed to cover all frequency bands below 1 GHz and is dedicated to biomedical applications with good matching, omnidirectional radiation, and a maximum realized gain of −26.7 dBi. It offers two bandwidths of 270 MHz and 762 MHz respectively. A Phantom model of the elliptical cylinder of 180 × 100 × 50 mm3 was used to simulate the electromagnetic radiation inside the human body. The tissue considered is equivalent to a muscle with a relative permittivity of 57 and a conductivity equal to 0.79 S/m. We also studied the antenna behavior when close to the internal electronic components. The simulation showed that the antenna remains robust in such an environment. Finally, the Specific Absorption Rate of the muscle was evaluated when the antenna was fed with 1 V. The evaluation proved that the calculated value of 0.48 W/Kg is well below the limit value imposed by the International Commission on Non-Ionizing Radiation Protection.
基金supported by the National Natural Science Foundation of China(Grant No.51768037)“Foundation of A Hundred Youth Talents Training Program of Lanzhou Jiaotong University.”。
文摘Purpose–Under different ground motion excitation modes,the spatial coupling effect of seismic response for the arch bridge with thrust,seismic weak parts and the internal force components of the control section of main arch ribs are analyzed.Design/methodology/approach–Taking a 490 m deck type railway steel truss arch bridge as the background,the dynamic calculation model of the whole bridge was established by SAP2000 software.The seismic response analyses under one-,two-and three-dimension(1D,2D and 3D)uniform ground motion excitations were carried out.Findings–For the steel truss arch bridge composed of multiple arch ribs,any single direction ground motion excitation will cause large axial force in the chord of arch rib.The axial force caused by transverse and vertical ground motion excitation in the chord of arch crown area is 1.4–3.6 times of the corresponding axial force under longitudinal seismic excitation.The in-plane bending moment caused by the lower chord at the vault is 4.2–5.5 times of the corresponding bending moment under the longitudinal seismic excitation.For the bottom chord of arch rib,the arch foot is the weak part of earthquake resistance,but for the upper chord of arch rib,the arch foot,arch crown and the intersection of column and upper chord can all be the potential earthquake-resistant weak parts.The normal stress of the bottom chord of the arch rib under multidimensional excitation is mainly caused by the axial force,but the normal stress of the upper chord of the arch rib is caused by the axial force,in-plane and out of plane bending moment.Originality/value–The research provides specific suggestions for ground motion excitation mode and also provides reference information for the earthquake-resistant weak part and seismic design of long-span deck type railway steel truss arch bridges.
