A high-g beam-mass structure accelerometer was designed.In this structure,by means of KOH back etching on the mass,V-groove structure was fabricated on the backside of the mass,so the weight of the mass and also the r...A high-g beam-mass structure accelerometer was designed.In this structure,by means of KOH back etching on the mass,V-groove structure was fabricated on the backside of the mass,so the weight of the mass and also the relative distance between the mass center and the neutral plane were all decreased.With the thin mass structure,we can take advantage of both beam-mass structure and flat film structure;the fabrication process is also simple.By means of Hopkinson shock test system,we did the accelerometer calibration.According to the test result,the sensitivity of the MEMS accelerometer is 0.71 μV/g,which keeps in accordance with the theoretical calculation.After a 200 000 g shocking test,the micro structure worked as usual,so this design can satisfy the requirements of high shock,seriously vibration test environment.展开更多
A triaxial high-g accelerometer of microelectro mechanical systems （MEMS） has a struc- ture of multi-chips combination and will be used in aerospace field, civil and military fields. The ac- celerometer can measure ...A triaxial high-g accelerometer of microelectro mechanical systems （MEMS） has a struc- ture of multi-chips combination and will be used in aerospace field, civil and military fields. The ac- celerometer can measure the acceleration of the carrier. The chips with island-membrane structures on its back surfaces are made by MEMS dry processing. The chip is reasonable and can work well under high impact load; Titanium alloy base is also stronger in high shock environment, these are proved by finite element analysis. Finally, the MEMS combined triaxial high-g accelerometer is vali- dated by high impact calibration experiments in order to get a key performance index, including range, sensitivity and transverse sensitivity and so on. These data can satisfy the need of design but some problems remain, these will be eliminated by improvement of the processing technology and materials.展开更多
This paper proposes a raptor-like low-density parity-check(RL-LDPC)code design together with the corresponding decoder hardware architecture aiming at next-generation mobile communication.A new kind of protograph diff...This paper proposes a raptor-like low-density parity-check(RL-LDPC)code design together with the corresponding decoder hardware architecture aiming at next-generation mobile communication.A new kind of protograph different from the 5G new radio(NR)LDPC basic matrix is presented,and a code construction algorithm is proposed to improve the error-correcting performance.A multi-core layered decoder architecture that supports up to 100 Gbit/s throughput is designed based on the special protograph structure.展开更多
Nowadays,high mobility scenarios have become increasingly common.The widespread adoption of High-speed Rail(HSR)in China exemplifies this trend,while more promising use cases,such as vehicle-to-everything,continue to ...Nowadays,high mobility scenarios have become increasingly common.The widespread adoption of High-speed Rail(HSR)in China exemplifies this trend,while more promising use cases,such as vehicle-to-everything,continue to emerge.However,the Internet access provided in high mobility environments stllstruggles to achieve seamless connectivity.The next generation of wireless cellular technology 5 G further poses more requirements on the endto-end evolution to fully utilize its ultra-high band-width,while existing network diagnostic tools focus on above-IP layers or below-IP layers only.We then propose HiMoDiag,which enables flexible online analysis of the network performance in a cross-layer manner,i.e.,from the top(application layer)to the bottom(physical layer).We believe HiMoDiag could greatly simplify the process of pinpointing the deficiencies of the Internet access delivery on HSR,lead to more timely optimization and ultimately help to improve the network performance.展开更多
目的在弹箭发射与侵彻时,弹箭系统内部测试电路元件承受高g值加载。为提高电路元件的存活度,需对其进行缓冲防护。方法利用气炮装置发射钢弹,撞击底座获得高g值加载,研究铝合金薄壁管的抗冲击特性,并基于LS-DYNA研究薄壁管壁厚和冲击速...目的在弹箭发射与侵彻时,弹箭系统内部测试电路元件承受高g值加载。为提高电路元件的存活度,需对其进行缓冲防护。方法利用气炮装置发射钢弹,撞击底座获得高g值加载,研究铝合金薄壁管的抗冲击特性,并基于LS-DYNA研究薄壁管壁厚和冲击速度对高g值冲击过程的影响。结果钢弹冲击速度增加,底座的激励加速度幅值(Acceleration Amplitude of Excitation,AAE)逐渐增加,单层管(CirT)和多胞管(MT)的缓冲效率分别达到91.0%和74.7%,数值模拟所得AAE和响应加速度幅值(Acceleration Amplitude of Response,AAR)与实验结果误差<5%,薄壁管壁厚对激励加速度几乎无影响。结论本文所得结果对轻质元件的高g值冲击防护有较强的指导意义。展开更多
A novel capacitive biaxial microaccelerometer with a highly symmetrical microstructure is developed. The sensor is composed of a single seismic mass, grid strip, supporting beam, joint beam, and damping adjusting comb...A novel capacitive biaxial microaccelerometer with a highly symmetrical microstructure is developed. The sensor is composed of a single seismic mass, grid strip, supporting beam, joint beam, and damping adjusting combs. The sensing method of changing capacitance area is used in the design,which depresses the requirement of the DRIE process, and de- creases electronic noise by increasing sensing voltage to improve the resolution. The parameters and characteristics of the biaxial microaccelerometer are discussed with the FEM tool ANSYS. The simulated results show that the transverse sensitivity of the sensor is equal to zero. The testing devices based on the slide-film damping effect are fabricated, and the testing quality factor is 514, which shows that the designed structure can improve the resolution and proves the feasibility of the designed process.展开更多
The freestyle Hopkinson bar is a kind of main high g loading equipment utilized widely in calibration of high g accelerometer and other high shock conditions. The calibration experiment of accelerometer was conducted....The freestyle Hopkinson bar is a kind of main high g loading equipment utilized widely in calibration of high g accelerometer and other high shock conditions. The calibration experiment of accelerometer was conducted. With one-dimension stress wave theory, ANSYS/LS-DYNA software and experiment, the effect rules of the projectile＇s front-head style and the accelerometer＇s mounted base＇s length on acceleration waveform were analyzed. The results show that the acceleration duration inspired from Hopkinson bar is almost equal to the rising edge time of perfect half sine stress wave, and it is independent to the mounted base＇s length. Moreover, the projectile＇s fronthead style is a main affecting factor, and the projectiles with less Conical degrees will produce the lower amplitude and longer acceleration duration.展开更多
基金Shanxi province young leaders on science and by program for New Century Excellent Talents in University(NCET)
文摘A high-g beam-mass structure accelerometer was designed.In this structure,by means of KOH back etching on the mass,V-groove structure was fabricated on the backside of the mass,so the weight of the mass and also the relative distance between the mass center and the neutral plane were all decreased.With the thin mass structure,we can take advantage of both beam-mass structure and flat film structure;the fabrication process is also simple.By means of Hopkinson shock test system,we did the accelerometer calibration.According to the test result,the sensitivity of the MEMS accelerometer is 0.71 μV/g,which keeps in accordance with the theoretical calculation.After a 200 000 g shocking test,the micro structure worked as usual,so this design can satisfy the requirements of high shock,seriously vibration test environment.
基金Supported by the National Natural Science Foundation of China(61273346)the National Defense Major Fundamental Research Program of China(20110003)+3 种基金the National Defense Key Fundamental Research Program of China(20132010)Specialized Research Fund for the Doctoral Program of Higher Education(20121101120009)Excellent Young Scholars Research Fund of Beijing Institute of Technology(2012YG0203)the Program for the Fundamental Research of Beijing Institute of Technology(2015CX02034)
文摘A triaxial high-g accelerometer of microelectro mechanical systems （MEMS） has a struc- ture of multi-chips combination and will be used in aerospace field, civil and military fields. The ac- celerometer can measure the acceleration of the carrier. The chips with island-membrane structures on its back surfaces are made by MEMS dry processing. The chip is reasonable and can work well under high impact load; Titanium alloy base is also stronger in high shock environment, these are proved by finite element analysis. Finally, the MEMS combined triaxial high-g accelerometer is vali- dated by high impact calibration experiments in order to get a key performance index, including range, sensitivity and transverse sensitivity and so on. These data can satisfy the need of design but some problems remain, these will be eliminated by improvement of the processing technology and materials.
基金supported in part by ZTE Industry-University-Institute Coop⁃eration funds under Grant No.2020ZTE01-03.
文摘This paper proposes a raptor-like low-density parity-check(RL-LDPC)code design together with the corresponding decoder hardware architecture aiming at next-generation mobile communication.A new kind of protograph different from the 5G new radio(NR)LDPC basic matrix is presented,and a code construction algorithm is proposed to improve the error-correcting performance.A multi-core layered decoder architecture that supports up to 100 Gbit/s throughput is designed based on the special protograph structure.
基金supported by National Key Research and Development Plan,China(Grant No.2020YFB1710900)National Natural Science Foundation of China(Grant No.62022005 and 62172008).
文摘Nowadays,high mobility scenarios have become increasingly common.The widespread adoption of High-speed Rail(HSR)in China exemplifies this trend,while more promising use cases,such as vehicle-to-everything,continue to emerge.However,the Internet access provided in high mobility environments stllstruggles to achieve seamless connectivity.The next generation of wireless cellular technology 5 G further poses more requirements on the endto-end evolution to fully utilize its ultra-high band-width,while existing network diagnostic tools focus on above-IP layers or below-IP layers only.We then propose HiMoDiag,which enables flexible online analysis of the network performance in a cross-layer manner,i.e.,from the top(application layer)to the bottom(physical layer).We believe HiMoDiag could greatly simplify the process of pinpointing the deficiencies of the Internet access delivery on HSR,lead to more timely optimization and ultimately help to improve the network performance.
文摘目的在弹箭发射与侵彻时,弹箭系统内部测试电路元件承受高g值加载。为提高电路元件的存活度,需对其进行缓冲防护。方法利用气炮装置发射钢弹,撞击底座获得高g值加载,研究铝合金薄壁管的抗冲击特性,并基于LS-DYNA研究薄壁管壁厚和冲击速度对高g值冲击过程的影响。结果钢弹冲击速度增加,底座的激励加速度幅值(Acceleration Amplitude of Excitation,AAE)逐渐增加,单层管(CirT)和多胞管(MT)的缓冲效率分别达到91.0%和74.7%,数值模拟所得AAE和响应加速度幅值(Acceleration Amplitude of Response,AAR)与实验结果误差<5%,薄壁管壁厚对激励加速度几乎无影响。结论本文所得结果对轻质元件的高g值冲击防护有较强的指导意义。
文摘A novel capacitive biaxial microaccelerometer with a highly symmetrical microstructure is developed. The sensor is composed of a single seismic mass, grid strip, supporting beam, joint beam, and damping adjusting combs. The sensing method of changing capacitance area is used in the design,which depresses the requirement of the DRIE process, and de- creases electronic noise by increasing sensing voltage to improve the resolution. The parameters and characteristics of the biaxial microaccelerometer are discussed with the FEM tool ANSYS. The simulated results show that the transverse sensitivity of the sensor is equal to zero. The testing devices based on the slide-film damping effect are fabricated, and the testing quality factor is 514, which shows that the designed structure can improve the resolution and proves the feasibility of the designed process.
文摘The freestyle Hopkinson bar is a kind of main high g loading equipment utilized widely in calibration of high g accelerometer and other high shock conditions. The calibration experiment of accelerometer was conducted. With one-dimension stress wave theory, ANSYS/LS-DYNA software and experiment, the effect rules of the projectile＇s front-head style and the accelerometer＇s mounted base＇s length on acceleration waveform were analyzed. The results show that the acceleration duration inspired from Hopkinson bar is almost equal to the rising edge time of perfect half sine stress wave, and it is independent to the mounted base＇s length. Moreover, the projectile＇s fronthead style is a main affecting factor, and the projectiles with less Conical degrees will produce the lower amplitude and longer acceleration duration.
