A periodic packing mode of trickle-bed reactor (TBR) for the gas limited reaction was proposed. Hy-drogenation of 2-ethylanthraquinone over Pd/Al2O3 in a laboratory-scale TBR was taken as a test reaction for determini...A periodic packing mode of trickle-bed reactor (TBR) for the gas limited reaction was proposed. Hy-drogenation of 2-ethylanthraquinone over Pd/Al2O3 in a laboratory-scale TBR was taken as a test reaction for determining whether the periodic packing mode is advantageous. The effects of operating conditions and packing type on TBR performance were experimentally examined to demonstrate the cause-effect relationships. A mathe-matic model of TBR considering axial dispersion and fractional wetting was developed to quantitatively illuminate the reason of performance enhancement.展开更多
Physiological parameters of people and enact assessment standard of indoor thermal environment that are appropriate to our national conditions were explored from the perspective of physiology. From December 2005 to Ja...Physiological parameters of people and enact assessment standard of indoor thermal environment that are appropriate to our national conditions were explored from the perspective of physiology. From December 2005 to January 2006, nerve conduction velocities and skin temperatures of 20 healthy students were tested with questionnaire investigation. The results show that the nerve conduction velocities as well as skin temperatures present an obvious decline trend in a continuous draught, and that the nerve conduction velocities and skin temperatures have a definite linear relationship. Draught velocity is an important factor in winter that affects body comfort, and the subjects are sensitive to air velocity.展开更多
The transfer alignment of SINS/GPS navigation system of a high-speed marine missile was investigated. With the help of the big acceleration of a high-speed missile, the transfer alignment was changed into a three-time...The transfer alignment of SINS/GPS navigation system of a high-speed marine missile was investigated. With the help of the big acceleration of a high-speed missile, the transfer alignment was changed into a three-time alignment. The azimuth alignment was coarsely finished in 10s in the first time alignment, the horizontal alignment was accurately and rapidly finished in the second time alignment, and the azimuth alignment was accurately finished in the third time alignment. Because the second time alignment and the third time alignment were finished by GPS after the missile was launched, the horizontal alignment and the second azimuth alignment got rid of the influence of the warship body flexibility deforming. The precision and rapidity of the horizontal alignment were prominently increased due to the vertical launch of the marine missile with the big acceleration. Simulation verifies the effectiveness of the proposed alignment method.展开更多
This paper covers why measurements at various speeds with CFME （continuous friction measurement equipment） are not able to measure the speed-friction gradient of the pavement as determined by the macro-textural feat...This paper covers why measurements at various speeds with CFME （continuous friction measurement equipment） are not able to measure the speed-friction gradient of the pavement as determined by the macro-textural features of the surface. Most CFMEs measure friction in the slip ratio range of 10% to 18%. In this range, it is shown that the friction versus slip speed of these devices are mainly determined by the coupled properties of the surface micro-texture and relevant tire properties and to a minimal extent only by pavement macro-texture properties. The determinacy of low slip ratio friction measurements on the macro-textural features of the pavement surface are shown to be so low that they are inadequate to capture macro-texture caused speed degradation of friction. It is also shown in the paper that close to 100% slip ratio measurements at a relatively wide speed scale or direct macro texture measurements are needed to adequately determine the speed gradient if friction caused by the pavement macro-texture. The data and analysis in this paper provide strong and compelling evidence that the EFI （European Friction Index） or EFI developed by the HERMES （Harmonization of European Routine and Research Measuring Equipment for Skid Resistance） project sponsored by FEHRL （Forum of European National Highway Research Laboratories） is strongly affected by the lack of consideration of this phenomenon. It is recommended that the results of the HERMES project are reviewed taking into account the findings of the present paper. Based on the results of the presented paper it is suggested that CFME＇s only measure friction at a fixed speed with a standard tire and use a macro-texture measuring device to obtain the pavement speed gradient.展开更多
The frequency stability of a marine power system is determined by the dynamic characteristic of the diesel engine speed regulation system in a marine power station. In order to reduce the effect of load disturbances a...The frequency stability of a marine power system is determined by the dynamic characteristic of the diesel engine speed regulation system in a marine power station. In order to reduce the effect of load disturbances and improve the dynamic precision of a diesel engine speed governor, a controller was designed for a diesel engine speed regulation system using H2 control theory. This transforms the specifications of the system into a standard H2 control problem. Firstly, the mathematical model of a diesel engine speed regulation system using an H2 speed governor is presented. To counter external disturbances and model uncertainty, the design of an H, speed governor rests on the problem of mixed sensitivity. Computer simulation verified that the H2 speed governor improves the dynamic precision of a system and the ability to adapt to load disturbances, thus enhancing the frequency stability of marine power systems.展开更多
The paper takes a method of a low speed processer based on FPGA hardware accelerator SOC units to realize the MP3 player, and include some peripheral devices. The experimental results show that the system has implemen...The paper takes a method of a low speed processer based on FPGA hardware accelerator SOC units to realize the MP3 player, and include some peripheral devices. The experimental results show that the system has implemented the basic functions of the MP3 player, having its own advantages on increasing the decoding speed and reducing the system consumption. The system is convenient to redesign for more function in the future. In conclusion, it has a wide application prospect.展开更多
A new device of reduction for seismic response using friction force was developed. In this paper, fundamental characteristics of reduction system for seismic response using this device were investigated by excitation ...A new device of reduction for seismic response using friction force was developed. In this paper, fundamental characteristics of reduction system for seismic response using this device were investigated by excitation experiment using artificial seismic waves. The peak acceleration amplitude on this system has decreased to about 50-90% over the input waves. Although a spectral peak around the frequency of 0.5Hz that is the natural period of this system was identified, the value of a spectral peak was decreased using bearings with the high friction force. This device is useful for reduction of seismic response.展开更多
This paper deals with an experimental study on dynamic fracture speed of three point bending specimen and cylindrical specimen made of epoxy resin by means of silver conductive painting grid. According to the test res...This paper deals with an experimental study on dynamic fracture speed of three point bending specimen and cylindrical specimen made of epoxy resin by means of silver conductive painting grid. According to the test results ,the relations between fracture load ,fracture speed and loading speed are discussed and the features of final fracture surfaces are analysed in detail.展开更多
This experiment was conducted in silty clay loam soil and cultivated with previous season wheat. Tillage for experiment field was applied using moldboard plow with 0.22-0.24 m depth, the rate of tractor velocity was 2...This experiment was conducted in silty clay loam soil and cultivated with previous season wheat. Tillage for experiment field was applied using moldboard plow with 0.22-0.24 m depth, the rate of tractor velocity was 2.45 km hf^-1, as a tillage velocity. Two rates of tractor velocities （first factor） were applied： 3.24 km hr^-1, for the first velocity, and 4.71 km hr^-1 for the second, Three types of tillers （second factor） were used： disk harrow, rotavator tiller, and spring spike tooth harrow. The first velocity rate was： 2.51 km hr-l（with disk harrow as a machinery unit）, 2.92 km hr^-1 （with rotivator）, and 3.06 km hrl（with spring spike tooth harrow）, while the second velocity rate was： 3.19 km hr-1 （with disk harrow as a machinery unit）, 4.05 km hrl（with rotivator）, and 4.26 km hrl（with spring spike tooth harrow）. Split plot design in RCBD with three replicates was used at the constant of soil moisture 11%-13%. Results were analyzed statistically and means were tested with LSD. The results showed the significant differences between both two experiment factors and their interaction for all study parameters which included： slippage percentage, practical productivity, numbers of masses 〉 5 cm m^-2, and the implement width. At the constant of pulverization equipment types, the higher percentage of slippage was 16.45%, the higher rate of practical productivity was 0.677 h hr1, and the higher rate of implement width was 2.05 m, while the rate of masses 〉 5 cm m-2 decreased to 13.8 mass m2. At the constant of velocity, disk harrow achieved higher slippage percentage 17.69%, spring spike tooth harrow tiller achieved higher practical productivity 0.858 h hr^-1 and higher rate of implement width 2.73 m, and the rotivator achieved the lower rate of masses 〉 5 cm m2 and 4.1 mass m2. The comparison among the three pulverization equipment typess was the purpose of this study to give the best studied indexes under two different velocities.展开更多
In chronic stage of stroke, it is necessary to pay attention to the complex spatial movements training along with the traditional restoration of balance, strength of particular muscles, and paretic limb joints mobilit...In chronic stage of stroke, it is necessary to pay attention to the complex spatial movements training along with the traditional restoration of balance, strength of particular muscles, and paretic limb joints mobility. The aim of the study was to evaluate the effectiveness of robotic therapy in the recovery of upper limb function in the chronic stage of stroke. The study involved 52 patients with ischemic stroke in the middle cerebral artery. The patients were divided randomly into 2 groups. All patients （5 days/wk × 3 wk） got gymnastics by the standard technique, massage, laser, and pulsed currents therapy. Main group patients （n = 36） extra received complex spatial movements, speed, fluidity, precision and agility training by the robotic electromechanical device Multi Joint System （MJS） （40 minutes, 5 days/wk × 3 wk）. Analysis of the results of the study showed a statistically significant difference in improving ROM of the elbow and shoulder joints, speed and accuracy of movement in the main group compared with the control. Hardware recovery of complex spatial upper limb movements in the chronic stage of stroke increases the functionality and independence of the patient＇s domestic skills.展开更多
基金the State Key Development Program for Basic Research of China (No. G2000048005) the SINOPEC (No.X503023).
文摘A periodic packing mode of trickle-bed reactor (TBR) for the gas limited reaction was proposed. Hy-drogenation of 2-ethylanthraquinone over Pd/Al2O3 in a laboratory-scale TBR was taken as a test reaction for determining whether the periodic packing mode is advantageous. The effects of operating conditions and packing type on TBR performance were experimentally examined to demonstrate the cause-effect relationships. A mathe-matic model of TBR considering axial dispersion and fractional wetting was developed to quantitatively illuminate the reason of performance enhancement.
基金Project(CSTC 2004AA7008) supported by the State I mportant Project of the Science and Technology
文摘Physiological parameters of people and enact assessment standard of indoor thermal environment that are appropriate to our national conditions were explored from the perspective of physiology. From December 2005 to January 2006, nerve conduction velocities and skin temperatures of 20 healthy students were tested with questionnaire investigation. The results show that the nerve conduction velocities as well as skin temperatures present an obvious decline trend in a continuous draught, and that the nerve conduction velocities and skin temperatures have a definite linear relationship. Draught velocity is an important factor in winter that affects body comfort, and the subjects are sensitive to air velocity.
文摘The transfer alignment of SINS/GPS navigation system of a high-speed marine missile was investigated. With the help of the big acceleration of a high-speed missile, the transfer alignment was changed into a three-time alignment. The azimuth alignment was coarsely finished in 10s in the first time alignment, the horizontal alignment was accurately and rapidly finished in the second time alignment, and the azimuth alignment was accurately finished in the third time alignment. Because the second time alignment and the third time alignment were finished by GPS after the missile was launched, the horizontal alignment and the second azimuth alignment got rid of the influence of the warship body flexibility deforming. The precision and rapidity of the horizontal alignment were prominently increased due to the vertical launch of the marine missile with the big acceleration. Simulation verifies the effectiveness of the proposed alignment method.
文摘This paper covers why measurements at various speeds with CFME （continuous friction measurement equipment） are not able to measure the speed-friction gradient of the pavement as determined by the macro-textural features of the surface. Most CFMEs measure friction in the slip ratio range of 10% to 18%. In this range, it is shown that the friction versus slip speed of these devices are mainly determined by the coupled properties of the surface micro-texture and relevant tire properties and to a minimal extent only by pavement macro-texture properties. The determinacy of low slip ratio friction measurements on the macro-textural features of the pavement surface are shown to be so low that they are inadequate to capture macro-texture caused speed degradation of friction. It is also shown in the paper that close to 100% slip ratio measurements at a relatively wide speed scale or direct macro texture measurements are needed to adequately determine the speed gradient if friction caused by the pavement macro-texture. The data and analysis in this paper provide strong and compelling evidence that the EFI （European Friction Index） or EFI developed by the HERMES （Harmonization of European Routine and Research Measuring Equipment for Skid Resistance） project sponsored by FEHRL （Forum of European National Highway Research Laboratories） is strongly affected by the lack of consideration of this phenomenon. It is recommended that the results of the HERMES project are reviewed taking into account the findings of the present paper. Based on the results of the presented paper it is suggested that CFME＇s only measure friction at a fixed speed with a standard tire and use a macro-texture measuring device to obtain the pavement speed gradient.
基金Supported by the National Natural Science Foundation of China under Grant No.60774072Heilongjiang Province Natural Science Foundation under Grant No.F01-24Harbin Engineering University Basic Research Foundation under Grant No. HEUFP05014.
文摘The frequency stability of a marine power system is determined by the dynamic characteristic of the diesel engine speed regulation system in a marine power station. In order to reduce the effect of load disturbances and improve the dynamic precision of a diesel engine speed governor, a controller was designed for a diesel engine speed regulation system using H2 control theory. This transforms the specifications of the system into a standard H2 control problem. Firstly, the mathematical model of a diesel engine speed regulation system using an H2 speed governor is presented. To counter external disturbances and model uncertainty, the design of an H, speed governor rests on the problem of mixed sensitivity. Computer simulation verified that the H2 speed governor improves the dynamic precision of a system and the ability to adapt to load disturbances, thus enhancing the frequency stability of marine power systems.
文摘The paper takes a method of a low speed processer based on FPGA hardware accelerator SOC units to realize the MP3 player, and include some peripheral devices. The experimental results show that the system has implemented the basic functions of the MP3 player, having its own advantages on increasing the decoding speed and reducing the system consumption. The system is convenient to redesign for more function in the future. In conclusion, it has a wide application prospect.
文摘A new device of reduction for seismic response using friction force was developed. In this paper, fundamental characteristics of reduction system for seismic response using this device were investigated by excitation experiment using artificial seismic waves. The peak acceleration amplitude on this system has decreased to about 50-90% over the input waves. Although a spectral peak around the frequency of 0.5Hz that is the natural period of this system was identified, the value of a spectral peak was decreased using bearings with the high friction force. This device is useful for reduction of seismic response.
文摘This paper deals with an experimental study on dynamic fracture speed of three point bending specimen and cylindrical specimen made of epoxy resin by means of silver conductive painting grid. According to the test results ,the relations between fracture load ,fracture speed and loading speed are discussed and the features of final fracture surfaces are analysed in detail.
文摘This experiment was conducted in silty clay loam soil and cultivated with previous season wheat. Tillage for experiment field was applied using moldboard plow with 0.22-0.24 m depth, the rate of tractor velocity was 2.45 km hf^-1, as a tillage velocity. Two rates of tractor velocities （first factor） were applied： 3.24 km hr^-1, for the first velocity, and 4.71 km hr^-1 for the second, Three types of tillers （second factor） were used： disk harrow, rotavator tiller, and spring spike tooth harrow. The first velocity rate was： 2.51 km hr-l（with disk harrow as a machinery unit）, 2.92 km hr^-1 （with rotivator）, and 3.06 km hrl（with spring spike tooth harrow）, while the second velocity rate was： 3.19 km hr-1 （with disk harrow as a machinery unit）, 4.05 km hrl（with rotivator）, and 4.26 km hrl（with spring spike tooth harrow）. Split plot design in RCBD with three replicates was used at the constant of soil moisture 11%-13%. Results were analyzed statistically and means were tested with LSD. The results showed the significant differences between both two experiment factors and their interaction for all study parameters which included： slippage percentage, practical productivity, numbers of masses 〉 5 cm m^-2, and the implement width. At the constant of pulverization equipment types, the higher percentage of slippage was 16.45%, the higher rate of practical productivity was 0.677 h hr1, and the higher rate of implement width was 2.05 m, while the rate of masses 〉 5 cm m-2 decreased to 13.8 mass m2. At the constant of velocity, disk harrow achieved higher slippage percentage 17.69%, spring spike tooth harrow tiller achieved higher practical productivity 0.858 h hr^-1 and higher rate of implement width 2.73 m, and the rotivator achieved the lower rate of masses 〉 5 cm m2 and 4.1 mass m2. The comparison among the three pulverization equipment typess was the purpose of this study to give the best studied indexes under two different velocities.
文摘In chronic stage of stroke, it is necessary to pay attention to the complex spatial movements training along with the traditional restoration of balance, strength of particular muscles, and paretic limb joints mobility. The aim of the study was to evaluate the effectiveness of robotic therapy in the recovery of upper limb function in the chronic stage of stroke. The study involved 52 patients with ischemic stroke in the middle cerebral artery. The patients were divided randomly into 2 groups. All patients （5 days/wk × 3 wk） got gymnastics by the standard technique, massage, laser, and pulsed currents therapy. Main group patients （n = 36） extra received complex spatial movements, speed, fluidity, precision and agility training by the robotic electromechanical device Multi Joint System （MJS） （40 minutes, 5 days/wk × 3 wk）. Analysis of the results of the study showed a statistically significant difference in improving ROM of the elbow and shoulder joints, speed and accuracy of movement in the main group compared with the control. Hardware recovery of complex spatial upper limb movements in the chronic stage of stroke increases the functionality and independence of the patient＇s domestic skills.
