A novel twin-rotor piston engine （TRPE） mechanism with high volumetric output and power density was introduced. This new engine comprises an energy conversion system and a differential velocity drive mechanism （DVD...A novel twin-rotor piston engine （TRPE） mechanism with high volumetric output and power density was introduced. This new engine comprises an energy conversion system and a differential velocity drive mechanism （DVDM）. Two special geared four-bar mechanisms, DVDM-1 and DVDM-2, were utilized and compared. Based on the closed loop vector method, a mathematical model for position, velocity, and acceleration of the two mechanisms was established. Numerical examples illustrate that the kinematic characteristics were presented. Expression of the displacement and compression ratio of the two engine mechanisms were derived and compared. It is concluded that both DVDM-1 and DVDM-2 adopted in the proposed TRPE with six vane pistons create thirty-six power strokes per revolution of the output shaft, and the summation of two angles covered by each rocker is always 2x/N as the output shaft rotates an angle of x/N. In DVDM-1, the span angle of a vane piston should be designed to be 10.2°, and the compression ratio should be equal to 10; in DVDM-2, the span angle of a vane piston should be designed to be 10.6°, and the compression ratio should be equal to 4.3.展开更多
During our research,It has been found that body acceleration has strong relationships with the human energy expenditure.This paper discusses the methods to assess physical activity and concludes that for accurate asse...During our research,It has been found that body acceleration has strong relationships with the human energy expenditure.This paper discusses the methods to assess physical activity and concludes that for accurate assessment of physical activity under free living conditions the recently introduced accelerometer looks most promising.We developed a new computerized machine to assess the body activity and energy expenditure.Test datas of the treadmill experiment,respiration experiment and 5-kilometer-running experiment have been archieved,we found that body acceration integrals with time has linear relations with body energy expenture.展开更多
The entire society is messing up with the idea of quick success and instant benefit,which throws people faster into desire,extravagance,fame and gain;and the fashion circle is at the frontier of this accelerated movem...The entire society is messing up with the idea of quick success and instant benefit,which throws people faster into desire,extravagance,fame and gain;and the fashion circle is at the frontier of this accelerated movement.Everyone is eager for overnight success.展开更多
Research indicates that high levels of sedentary behavior(sitting or lying with low energy expenditure) are adversely associated with health. A key factor in improving our understanding of the impact of sedentary beha...Research indicates that high levels of sedentary behavior(sitting or lying with low energy expenditure) are adversely associated with health. A key factor in improving our understanding of the impact of sedentary behavior(and patterns of sedentary time accumulation) on health is the use of objective measurement tools that collect date and time-stamped activity information. One such tool is the activP AL monitor. This thigh-worn device uses accelerometer-derived information about thigh position to determine the start and end of each period spent sitting/lying, standing, and stepping, as well as stepping speed, step counts, and postural transitions. The activP AL is increasingly being used within field-based research for its ability to measure sitting/lying via posture. We summarise key issues to consider when using the activP AL in physical activity and sedentary behavior field-based research with adult populations. It is intended that the findings and discussion points be informative for researchers who are currently using activP AL monitors or are intending to use them. Pre-data collection decisions, monitor preparation and distribution, data collection considerations, and manual and automated data processing possibilities are presented using examples from current literature and experiences from 2 research groups from the UK and Australia.展开更多
The traffic-induced vibrations of the new CCTV Headquarters building are studied stages. In the first stage when the through experiments in two 30th floor of the northwest tower and the 38th floor of the southeast tow...The traffic-induced vibrations of the new CCTV Headquarters building are studied stages. In the first stage when the through experiments in two 30th floor of the northwest tower and the 38th floor of the southeast tower were finished, the traffic flows on the roads surrounding the building were investigated, and 27 setups of accelerations were measured at the roadside, on the pile cap and on the 9th floor. In the second stage when the whole steel structure was completed, l 5 setups of accelerations were measured at the roadside, on the pile cap and on the 37th and the 48th floors. The accelerations of the building under different traffic flows, in different positions are analyzed in both time domain and frequency domain. The damping ratios are estimated by the upgraded half-power bandwidth method.展开更多
There is expounded the theory of＂gravitational＂ wave propagation from the volcano crater （magma） under changing density of magma mass inside the volcano. It was revealed that while the abruptly accelerated magma m...There is expounded the theory of＂gravitational＂ wave propagation from the volcano crater （magma） under changing density of magma mass inside the volcano. It was revealed that while the abruptly accelerated magma movement during starting period began eruption, the registered ＂gravitational＂ waves were being emitted and were propagating with the velocity greater than that of sound and seismic waves velocity. Alteration of ＂gravitational＂ waves velocity under the magma movement can be additional feature in prognosis of the start time of volcano eruption. The considered method might be effective when making up prognoses of underwater volcano eruption.展开更多
Using the hybrid finite difference method, we solve the Fokker-Planck equation to study the effect of seed electron injection on acceleration of radiation belt electrons driven by chorus waves. Numerical results show ...Using the hybrid finite difference method, we solve the Fokker-Planck equation to study the effect of seed electron injection on acceleration of radiation belt electrons driven by chorus waves. Numerical results show that in the absence of injection chorus waves can accelerate electrons at large pitch angles （ae〉60°）, producing enhancements in the phase space density （PSD） of （1-2 MeV ） electrons by a factor of 100-1000 within 1-2 days. In the presence of injection, chorus waves yield increase in PSD of electrons by accelerating the injected seed electrons. Meanwhile, the PSD evolution increases as the pitch angle in- creases but decreases as electron energy increases. Moreover, the PSD evolution can extend to higher energies with a time scale of 1-2 days for 1-2 MeV energies. When the injection increases by a factor of 10 higher than the initial value and re- mains for about two days, maximum values of PSD for 1 or 2 MeV increase to 6 or 3 times respectively higher than those without injection in two days. The current results suggest that the injected seed electrons play an important role in the evolu- tion of the radiation belt electrons.展开更多
Effects of ions charge-mass ratio on energy and energy spread of accelerated ions in laser driven plasma are investigated in detail by proposing a simple double-layer model for a foil target driven by an ultrastrong l...Effects of ions charge-mass ratio on energy and energy spread of accelerated ions in laser driven plasma are investigated in detail by proposing a simple double-layer model for a foil target driven by an ultrastrong laser. The radiation pressure acceleration mechanism plays an important role on the studied problem. For the ions near the plasma mirror, i.e. electrons layer, the dependence of ions energy on their charge-mass ratio is derived theoretically. It is found that the larger the charge-mass ratio is, the higher the accelerated ions energy gets. For those ions far away from the layer, the dependence of energy and energy spread on ions charge-mass ratio are also obtained by numerical performance. It exhibits that, as ions charge-mass ratio increases, not only the accelerated ions energy but also the energy spread will become large.展开更多
基金Project(7131109) supported the by National Defense Pre-research Foundation of ChinaProject(50975278) supported by National the Natural Science Foundation of China
文摘A novel twin-rotor piston engine （TRPE） mechanism with high volumetric output and power density was introduced. This new engine comprises an energy conversion system and a differential velocity drive mechanism （DVDM）. Two special geared four-bar mechanisms, DVDM-1 and DVDM-2, were utilized and compared. Based on the closed loop vector method, a mathematical model for position, velocity, and acceleration of the two mechanisms was established. Numerical examples illustrate that the kinematic characteristics were presented. Expression of the displacement and compression ratio of the two engine mechanisms were derived and compared. It is concluded that both DVDM-1 and DVDM-2 adopted in the proposed TRPE with six vane pistons create thirty-six power strokes per revolution of the output shaft, and the summation of two angles covered by each rocker is always 2x/N as the output shaft rotates an angle of x/N. In DVDM-1, the span angle of a vane piston should be designed to be 10.2°, and the compression ratio should be equal to 10; in DVDM-2, the span angle of a vane piston should be designed to be 10.6°, and the compression ratio should be equal to 4.3.
文摘During our research,It has been found that body acceleration has strong relationships with the human energy expenditure.This paper discusses the methods to assess physical activity and concludes that for accurate assessment of physical activity under free living conditions the recently introduced accelerometer looks most promising.We developed a new computerized machine to assess the body activity and energy expenditure.Test datas of the treadmill experiment,respiration experiment and 5-kilometer-running experiment have been archieved,we found that body acceration integrals with time has linear relations with body energy expenture.
文摘The entire society is messing up with the idea of quick success and instant benefit,which throws people faster into desire,extravagance,fame and gain;and the fashion circle is at the frontier of this accelerated movement.Everyone is eager for overnight success.
基金supported by the National Institute for Health Researsch (NIHR) DietLifestyle & Physical Activity Biomedical Research Unit based at University Hospitals of Leicester and Loughborough University+5 种基金the National Institute for Health Research Collaboration for Leadership in Applied Health Research and Care-East Midlands (NIHR CLAHRC- EM)the Leicester Clinical Trials Unitsupported by a National Health and Medical Research Council (NHMRC) Centre for Research Excellence Grant on Sitting Time and Chronic Disease Prevention-Measurement, Mechanisms and Interventions (APP1057608)supported by a Heart Foundation Postdoctoral (PH 12B 7054)NHMRC Career Development (#1086029) Fellowshipsupported by an Australian Research Council Future Fellowship (FTE 100100918)
文摘Research indicates that high levels of sedentary behavior(sitting or lying with low energy expenditure) are adversely associated with health. A key factor in improving our understanding of the impact of sedentary behavior(and patterns of sedentary time accumulation) on health is the use of objective measurement tools that collect date and time-stamped activity information. One such tool is the activP AL monitor. This thigh-worn device uses accelerometer-derived information about thigh position to determine the start and end of each period spent sitting/lying, standing, and stepping, as well as stepping speed, step counts, and postural transitions. The activP AL is increasingly being used within field-based research for its ability to measure sitting/lying via posture. We summarise key issues to consider when using the activP AL in physical activity and sedentary behavior field-based research with adult populations. It is intended that the findings and discussion points be informative for researchers who are currently using activP AL monitors or are intending to use them. Pre-data collection decisions, monitor preparation and distribution, data collection considerations, and manual and automated data processing possibilities are presented using examples from current literature and experiences from 2 research groups from the UK and Australia.
基金The study is sponsored by the National Natural Science Foundation of China （No. 50538010） and the Flander （Belgium）-China Bilateral Project （,No. BIL 07/07）.
文摘The traffic-induced vibrations of the new CCTV Headquarters building are studied stages. In the first stage when the through experiments in two 30th floor of the northwest tower and the 38th floor of the southeast tower were finished, the traffic flows on the roads surrounding the building were investigated, and 27 setups of accelerations were measured at the roadside, on the pile cap and on the 9th floor. In the second stage when the whole steel structure was completed, l 5 setups of accelerations were measured at the roadside, on the pile cap and on the 37th and the 48th floors. The accelerations of the building under different traffic flows, in different positions are analyzed in both time domain and frequency domain. The damping ratios are estimated by the upgraded half-power bandwidth method.
文摘There is expounded the theory of＂gravitational＂ wave propagation from the volcano crater （magma） under changing density of magma mass inside the volcano. It was revealed that while the abruptly accelerated magma movement during starting period began eruption, the registered ＂gravitational＂ waves were being emitted and were propagating with the velocity greater than that of sound and seismic waves velocity. Alteration of ＂gravitational＂ waves velocity under the magma movement can be additional feature in prognosis of the start time of volcano eruption. The considered method might be effective when making up prognoses of underwater volcano eruption.
基金supported by the Initiative Project of Chinese Academy of Sciences (Grant No. YYYJ-1110)
文摘Using the hybrid finite difference method, we solve the Fokker-Planck equation to study the effect of seed electron injection on acceleration of radiation belt electrons driven by chorus waves. Numerical results show that in the absence of injection chorus waves can accelerate electrons at large pitch angles （ae〉60°）, producing enhancements in the phase space density （PSD） of （1-2 MeV ） electrons by a factor of 100-1000 within 1-2 days. In the presence of injection, chorus waves yield increase in PSD of electrons by accelerating the injected seed electrons. Meanwhile, the PSD evolution increases as the pitch angle in- creases but decreases as electron energy increases. Moreover, the PSD evolution can extend to higher energies with a time scale of 1-2 days for 1-2 MeV energies. When the injection increases by a factor of 10 higher than the initial value and re- mains for about two days, maximum values of PSD for 1 or 2 MeV increase to 6 or 3 times respectively higher than those without injection in two days. The current results suggest that the injected seed electrons play an important role in the evolu- tion of the radiation belt electrons.
基金Supported by the National Natural Science Foundation of China (NNSFC) under Grant Nos. 11175023 and 10834008partially by the Fundamental Research Funds for the Central Universities (FRFCU)
文摘Effects of ions charge-mass ratio on energy and energy spread of accelerated ions in laser driven plasma are investigated in detail by proposing a simple double-layer model for a foil target driven by an ultrastrong laser. The radiation pressure acceleration mechanism plays an important role on the studied problem. For the ions near the plasma mirror, i.e. electrons layer, the dependence of ions energy on their charge-mass ratio is derived theoretically. It is found that the larger the charge-mass ratio is, the higher the accelerated ions energy gets. For those ions far away from the layer, the dependence of energy and energy spread on ions charge-mass ratio are also obtained by numerical performance. It exhibits that, as ions charge-mass ratio increases, not only the accelerated ions energy but also the energy spread will become large.
