The problems of hybrid input of mechanical press are studied in this paper, with differential gear train as transmission mechanism. It is proposed that “adjust-able-speed amplitude” or “differential-speed ratio” i...The problems of hybrid input of mechanical press are studied in this paper, with differential gear train as transmission mechanism. It is proposed that “adjust-able-speed amplitude” or “differential-speed ratio” is the important parameters for the hybrid input mechanism. It not only defines the amplitude of the adjustable speed, but also determines the ratio of the power of the servomotor to the power of the conventional motor. The calculating equations of the ratio of transmission in all axes, the power of two motors, and the working load distribution are deduced. The two kinds of driving schemes are put forward that the servomotor and the conven-tional motor simultaneously drive and the servomotor and the conventional motor separately drive. The calculating results demonstrate that the latter scheme can use much lower power of the servomotor, so this scheme makes manufacture and use cost much lower. The latter scheme proposes a feasible way to apply the hybrid mechanism of mechanical press in practice engineering.展开更多
Three-dimensional(3D)ordered porous carbon is generally believed to be a promising electromagnetic wave(EMW)absorbing material.However,most research works targeted performance improvement of 3D ordered porous carbon,a...Three-dimensional(3D)ordered porous carbon is generally believed to be a promising electromagnetic wave(EMW)absorbing material.However,most research works targeted performance improvement of 3D ordered porous carbon,and the specific attenuation mechanism is still ambiguous.Therefore,in this work,a novel ultra-light egg-derived porous carbon foam(EDCF)structure has been successfully constructed by a simple carbonization combined with the silica microsphere template-etching process.Based on an equivalent substitute strategy,the influence of pore volume and specific surface area on the electromagnetic parameters and EMW absorption properties of the EDCF products was confirmed respectively by adjusting the addition content and diameter of silica microspheres.As a primary attenuation mode,the dielectric loss originates from the comprehensive effect of conduction loss and polarization loss in S-band and C band,and the value is dominated by polarization loss in X band and Ku band,which is obviously greater than that of conduction loss.Furthermore,in all samples,the largest effective absorption bandwidth of EDCF-3 is 7.12 GHz under the thickness of 2.13 mm with the filling content of approximately 5 wt%,covering the whole Ku band.Meanwhile,the EDCF-7 sample with optimized pore volume and specific surface area achieves minimum reflection loss(RL_(min))of−58.08 dB at 16.86 GHz while the thickness is 1.27 mm.The outstanding research results not only provide a novel insight into enhancement of EMW absorption properties but also clarify the dominant dissipation mechanism for the porous carbon-based absorber from the perspective of objective experiments.展开更多
An innovative design of electric suspensions was developed in this study to help realize slow active suspension easily and quickly.This design was driven by screw through double slider-rod arranged symmetrically as a ...An innovative design of electric suspensions was developed in this study to help realize slow active suspension easily and quickly.This design was driven by screw through double slider-rod arranged symmetrically as a substitute for two springs.Based on a mathematical modeling,suspension parameters were introduced for a certain type of wheeled vehicles.The functions and its mechanism in regulating terrain clearance and adjusting attitudes were subsequently explained respectively,together with its semi-active control mechanism and characteristics In conclusion,our data in the study show that the new mechanical design of suspensions not only could realize adjusting terrain clearance and static vehicle pose,but also had an ideal stiffness that could realize a semi-active suspension function through adjusting suspension＇s stiffness.Therefore it can bequite suitable for off-road wheeled vehicles and military wheeled vehicles.展开更多
基金the National Natural Science Foundation of China (Grant No. 50575175)
文摘The problems of hybrid input of mechanical press are studied in this paper, with differential gear train as transmission mechanism. It is proposed that “adjust-able-speed amplitude” or “differential-speed ratio” is the important parameters for the hybrid input mechanism. It not only defines the amplitude of the adjustable speed, but also determines the ratio of the power of the servomotor to the power of the conventional motor. The calculating equations of the ratio of transmission in all axes, the power of two motors, and the working load distribution are deduced. The two kinds of driving schemes are put forward that the servomotor and the conven-tional motor simultaneously drive and the servomotor and the conventional motor separately drive. The calculating results demonstrate that the latter scheme can use much lower power of the servomotor, so this scheme makes manufacture and use cost much lower. The latter scheme proposes a feasible way to apply the hybrid mechanism of mechanical press in practice engineering.
基金supported by the National Natural Science Foundation of China under Grant No.52072196,52002199,52002200,52102106Major Basic Research Program of Natural Science Foundation of Shandong Province under Grant No.ZR2020ZD09+2 种基金the Natural Science Foundation of Shandong Province under Grant No.ZR2019BEM042,ZR2020QE063the Innovation and Technology Program of Shandong Province under Grant No.2020KJA004the Taishan Scholars Program of Shandong Province under No.ts201511034
文摘Three-dimensional(3D)ordered porous carbon is generally believed to be a promising electromagnetic wave(EMW)absorbing material.However,most research works targeted performance improvement of 3D ordered porous carbon,and the specific attenuation mechanism is still ambiguous.Therefore,in this work,a novel ultra-light egg-derived porous carbon foam(EDCF)structure has been successfully constructed by a simple carbonization combined with the silica microsphere template-etching process.Based on an equivalent substitute strategy,the influence of pore volume and specific surface area on the electromagnetic parameters and EMW absorption properties of the EDCF products was confirmed respectively by adjusting the addition content and diameter of silica microspheres.As a primary attenuation mode,the dielectric loss originates from the comprehensive effect of conduction loss and polarization loss in S-band and C band,and the value is dominated by polarization loss in X band and Ku band,which is obviously greater than that of conduction loss.Furthermore,in all samples,the largest effective absorption bandwidth of EDCF-3 is 7.12 GHz under the thickness of 2.13 mm with the filling content of approximately 5 wt%,covering the whole Ku band.Meanwhile,the EDCF-7 sample with optimized pore volume and specific surface area achieves minimum reflection loss(RL_(min))of−58.08 dB at 16.86 GHz while the thickness is 1.27 mm.The outstanding research results not only provide a novel insight into enhancement of EMW absorption properties but also clarify the dominant dissipation mechanism for the porous carbon-based absorber from the perspective of objective experiments.
基金Supported by the Ministerial Level Research Foundation(4030.4)
文摘An innovative design of electric suspensions was developed in this study to help realize slow active suspension easily and quickly.This design was driven by screw through double slider-rod arranged symmetrically as a substitute for two springs.Based on a mathematical modeling,suspension parameters were introduced for a certain type of wheeled vehicles.The functions and its mechanism in regulating terrain clearance and adjusting attitudes were subsequently explained respectively,together with its semi-active control mechanism and characteristics In conclusion,our data in the study show that the new mechanical design of suspensions not only could realize adjusting terrain clearance and static vehicle pose,but also had an ideal stiffness that could realize a semi-active suspension function through adjusting suspension＇s stiffness.Therefore it can bequite suitable for off-road wheeled vehicles and military wheeled vehicles.
