Active vibration control and stability analysis of cantilever plate are discussed. Based on the analysis of characteristic equation of the closed loop control system, it is shown that such an active control may incre...Active vibration control and stability analysis of cantilever plate are discussed. Based on the analysis of characteristic equation of the closed loop control system, it is shown that such an active control may increase damping properties of the system, meanwhile it may result in instability of the system. It is stable when the feedback only occurs between the collocated sensors and actuators, but it may be unstable when there exists the feedback between sensors and actuators, which mainly depends on the property of the gain matrix of feedback. If the gain matrix is symmetric and definitely positive, the system is stable.展开更多
In order to study the transmission efficiency of engine and optimize the structure of driving wheel,the rotational speed storage test device of driving wheel in tracked vehicle based on magnetoelectric sensor was desi...In order to study the transmission efficiency of engine and optimize the structure of driving wheel,the rotational speed storage test device of driving wheel in tracked vehicle based on magnetoelectric sensor was designed.The device consisted of a mounting bracket,a sensor and a tester.The mounting bracket was installed in vehicle body after fixing the tester and sensor to mounting bracket beside the driving wheel.Using the storage test instrument,the wireless trigger technology was applied to synchronously record and stored the rotational speed data of the driving wheel in tracked vehicle.After the experiment was finished,the data was read out through the upper computer.Both valid data and satisfactory results were obtained through both simulated and actual vehicle tests.展开更多
In this paper, eddy current sensors and thermocouple sensors were employed to measure the thermal field and thermal deformation of a spindle of a telescopic CNC boring-milling machine tool, respectively. A linear regr...In this paper, eddy current sensors and thermocouple sensors were employed to measure the thermal field and thermal deformation of a spindle of a telescopic CNC boring-milling machine tool, respectively. A linear regression method was proposed to establish the thermal error model. Furthermore, two compensation methods were implemented based on the SIEMENS 840D system by using the feed shaft of z direction and telescopic spindle respectively. Experimental results showed that the thermal error could be reduced by 73.79% when using the second compensation method, and the thermal error could be eliminated by using the two compensation methods effectively.展开更多
Aluminum （AI）, Vanadium （V）, Chromium （Cr）, Manganese （Mn）, Iron （Fe）, Strontium （Sr）, Molybdenum （Mo）, Silver （Ag）, Cadmium （Cd）, Tin （Sn）, Caesium （Cs）, Barium （Ba）, Lead （Pb）, Bismuth （Bi...Aluminum （AI）, Vanadium （V）, Chromium （Cr）, Manganese （Mn）, Iron （Fe）, Strontium （Sr）, Molybdenum （Mo）, Silver （Ag）, Cadmium （Cd）, Tin （Sn）, Caesium （Cs）, Barium （Ba）, Lead （Pb）, Bismuth （Bi） and Uranium （U） concentrations were investigated in water samples from fifteen sampling locations in Naviundu river basin, Luano and Ruashi rivers and Luwowoshi spring in Lubumbashi city during February, March and April 2016. Chemical analyses of the samples were carried out using Inductively Coupled Plasma-Mass Spectrometer. Water pH was determined using a pH-meter and mean pH values ranged from 4.2 to 5.8. The highest mean levels of Al （5,961.954 μg·L^-1）, Pb （472.287 μg·L^-1）, V （21.014 μg·L^-1）, Cr （8.185μg·L^-1）, U （4.163μg·L^-1） and Bi （0.012 μg·L^-1） were recorded in Chemaf （Chemicals of Africa） hydrometallurgical plant effluent, those of Mn （29,714.593 μg·L^-1）, Sr （374.377μg·L^-1）, Cd （11.358μg·L^-1） and Cs （0.107μg·L^-1） in Naviundu river at Cimenkat （Katanga＇s Cement Factory） exit, those of Fe （14,258.9 μg·L^-1） and Ba （307.641μg·L^-1） in Luano river and those of Ag （2.669 μg·L^-1）, Mo （0.559 μg·L^-1） and Sn （0.325 μg·L^-1） were respectively noted in Foire channel, Naviundu river under bridge on Kasenga road and Kalulako river. The concentrations of Cd in Naviundu river at Cimenkat exit （11.358 μg·L^-1）, Chemaf bydrometallurgical plant effluent （9.697μg·L^-1）, Naviundu river under bridge on De Plaines Avenue （6.95 μg·L^-1） and Kalulako river （3.229 μg·L^-1）, Pb concentrations in Chemaf hydrometallurgical plant effluent （472.287 μg·L^-1） as well as the AI, Fe and Mn concentrations recorded in most waters in this study exceeded the WHO （World Health Organization） maximum permissible limits for drinking water. The metal contamination of waters of the studied rivers, channel and spring might be partially attributed to natural processes, unplanned urbanization and poor waste management, and mostly to abandoned and ongoing mining and ore processing activities in Lubumbashi city.展开更多
Concentrations of fifteen trace metals including Aluminum （Al）, Vanadium （V）, Chromium （Cr）, Manganese （Mn）, Iron （Fe）, Strontium （Sr）, Molybdenum （Mo）, Silver （Ag）, Cadmium （Cd）, Tin （Sn）, Caesium...Concentrations of fifteen trace metals including Aluminum （Al）, Vanadium （V）, Chromium （Cr）, Manganese （Mn）, Iron （Fe）, Strontium （Sr）, Molybdenum （Mo）, Silver （Ag）, Cadmium （Cd）, Tin （Sn）, Caesium （Cs）, Barium （Ba）, Lead （Pb）, Bismuth （Bi） and Uranium （U） were investigated in water samples collected from sixteen sampling locations in the Lubumbashi river basin and five locations in Kafubu, Kimilolo and Kinkalabwamba rivers during February, March and April 2016. Chemical analyses of the samples were carried out using ICP-MS （Inductively Coupled Plasma-Mass Spectrometer）. Water pH was determined using a pH-meter and pH values ranged from 4.2 to 7.8. The highest mean trace metal levels of water were 5,515.816 ）μg·L^-1, 166.925μg·L^-1, 3.898μg·L^-1 and 1.879μg·L^-1 for Al, Ba, Cr and U, respectively in Kashobwe river, 2,419.522 μg·L^-1 and 17.994 μg·L^-1 for Fe and Cd, respectively in Kafubu river at its confluence with Lubumbashi rivers, 1,408.136μg·L^-1 for Mn in Kafubu river 1.36 kilometer downward its confluence with Naviundu river, 222.406 μg·L^-1 and 0.092 μg·L^-1 for Sr and Cs, respectively in Kamalondo river 60 meters from the GCM-Lubumbashi （General of Quarries and Mines-Lubumbashi） smelter, 140.294μg·L^-1, 12.063 μg·L^-1 and 0.008μg·L^-1 for Pb, V and Bi, respectively in Munua river, 3.544 μg·L^-1 for Ag in Kabulameshi river, 1.49 μg·L^-1 for Mo in Kafubu river and 0.081μg·L^-1 for Sn in Tshondo river. The mean concentrations of Al, Cd, Fe, Mn and Pb in water of many rivers and the channel exceeded the maximum admissible limits of the WHO （World Health Organization）, USEPA （United States Environmental Protection Agency） and EU （European Union） drinking-water standards. Trace metal contamination of water of the studied rivers, channel and springs might be partially attributed to natural processes, unplanned urbanization, poor waste management and mostly to abandoned and ongoing mining and ore processing activities in Lubumbashi city.展开更多
A simple autonomous docking method based on infrared sensors for mobile self-reconfigurable relay microrobots is proposed in the paper.The IR guidance system composed of an IR receiver and four IR emitters is designed...A simple autonomous docking method based on infrared sensors for mobile self-reconfigurable relay microrobots is proposed in the paper.The IR guidance system composed of an IR receiver and four IR emitters is designed,analyzed and developed.The autonomous docking control method based on centering alignment and dynamic motion planning is adopted so that it has high efficiency and reliability.Two basic microrobot prototypes are developed,and related docking experiments are done to verify the feasibility of the approach.展开更多
As described in this paper, we propose a new haptic interface for a service robot. For safety with service robots working in a space where people live, some notification before collision with an obstacle is desirable....As described in this paper, we propose a new haptic interface for a service robot. For safety with service robots working in a space where people live, some notification before collision with an obstacle is desirable. To achieve such a function, we developed a master-slave manipulator system in which the slave manipulator surface is covered with many proximity sensors. Additionally, we developed a haptic device that feeds back proximity sense information to the operator using small vibration motors. We attached the haptic device to the arm of the operator and vibrated the vibration motor corresponding to the sensor. Thereby, the operator was able to ascertain the position of an object near the manipulator, and to make the robot maneuver to avoid it before collision. To confirm the system usefulness, we equipped subjects with the developed proximity sense presentation device and performed a detection-position-specific experiment and an obstacle avoidance experiment in a narrow space. As results of the detection position specific experiment on five subjects, four subjects reported the detection position correctly. The remaining one person failed because of his particular arm shape. Operation experiments conducted in a narrow space showed that all subjects＇ work was successful when given feedback of proximity sense information. Nobody was successful without proximity sense information. Results of these two experiments demonstrate that this proposed system is useful for obstacle avoidance of a master-slave manipulator system.展开更多
Many receptors,including thermal receptors and mechanical receptors,are only activated by stimuli within a clearly defined range of intensities.Differences in the receptive ranges enable individual receptors and their...Many receptors,including thermal receptors and mechanical receptors,are only activated by stimuli within a clearly defined range of intensities.Differences in the receptive ranges enable individual receptors and their sensory centers to precisely detect the intensity of the stimulus and changes in intensity.Baroreceptors are the sensory terminals of the baroreflex.It is well understood that an increasing number of baroreceptors are recruited to produce afferent action potentials as the blood pressure increases,indicating that individual baroreceptors have different pressure thresholds.The present study revealed that individual baroreceptors could stop their afferent signals when the blood pressure exceeds a certain level,indicating that individual baroreceptors are sensitive to a specific range of blood pressure.The receptive ranges of individual baroreceptors differ in terms of the total range,the lower threshold,and the upper threshold.Of 85 baroreceptors examined in this study,the upper thresholds for about half were within the physiological blood pressure range.These results indicate that supraphysiological blood pressure is unlikely to be encoded by the recruitment of more baroreceptors.Instead,supraphysiological blood pressure levels might be signaled by an increase in the frequency of action potentials or by other mechanisms.In conclusion,our results indicate that rabbit baroreceptors are activated by blood pressure levels within specific receptive ranges.These findings should encourage further studies to examine the role of population coding of blood pressure by baroreceptors in the baroreflex.展开更多
文摘Active vibration control and stability analysis of cantilever plate are discussed. Based on the analysis of characteristic equation of the closed loop control system, it is shown that such an active control may increase damping properties of the system, meanwhile it may result in instability of the system. It is stable when the feedback only occurs between the collocated sensors and actuators, but it may be unstable when there exists the feedback between sensors and actuators, which mainly depends on the property of the gain matrix of feedback. If the gain matrix is symmetric and definitely positive, the system is stable.
基金Cultivation Programs for Young Scientific Research Personnel of Higher Education Institutions in Shanxi Province(No.2019QPJH18)Fund for“1331 Project”Key Innovative Research Team of Shanxi Province(No.1331KIPT)。
文摘In order to study the transmission efficiency of engine and optimize the structure of driving wheel,the rotational speed storage test device of driving wheel in tracked vehicle based on magnetoelectric sensor was designed.The device consisted of a mounting bracket,a sensor and a tester.The mounting bracket was installed in vehicle body after fixing the tester and sensor to mounting bracket beside the driving wheel.Using the storage test instrument,the wireless trigger technology was applied to synchronously record and stored the rotational speed data of the driving wheel in tracked vehicle.After the experiment was finished,the data was read out through the upper computer.Both valid data and satisfactory results were obtained through both simulated and actual vehicle tests.
文摘In this paper, eddy current sensors and thermocouple sensors were employed to measure the thermal field and thermal deformation of a spindle of a telescopic CNC boring-milling machine tool, respectively. A linear regression method was proposed to establish the thermal error model. Furthermore, two compensation methods were implemented based on the SIEMENS 840D system by using the feed shaft of z direction and telescopic spindle respectively. Experimental results showed that the thermal error could be reduced by 73.79% when using the second compensation method, and the thermal error could be eliminated by using the two compensation methods effectively.
文摘Aluminum （AI）, Vanadium （V）, Chromium （Cr）, Manganese （Mn）, Iron （Fe）, Strontium （Sr）, Molybdenum （Mo）, Silver （Ag）, Cadmium （Cd）, Tin （Sn）, Caesium （Cs）, Barium （Ba）, Lead （Pb）, Bismuth （Bi） and Uranium （U） concentrations were investigated in water samples from fifteen sampling locations in Naviundu river basin, Luano and Ruashi rivers and Luwowoshi spring in Lubumbashi city during February, March and April 2016. Chemical analyses of the samples were carried out using Inductively Coupled Plasma-Mass Spectrometer. Water pH was determined using a pH-meter and mean pH values ranged from 4.2 to 5.8. The highest mean levels of Al （5,961.954 μg·L^-1）, Pb （472.287 μg·L^-1）, V （21.014 μg·L^-1）, Cr （8.185μg·L^-1）, U （4.163μg·L^-1） and Bi （0.012 μg·L^-1） were recorded in Chemaf （Chemicals of Africa） hydrometallurgical plant effluent, those of Mn （29,714.593 μg·L^-1）, Sr （374.377μg·L^-1）, Cd （11.358μg·L^-1） and Cs （0.107μg·L^-1） in Naviundu river at Cimenkat （Katanga＇s Cement Factory） exit, those of Fe （14,258.9 μg·L^-1） and Ba （307.641μg·L^-1） in Luano river and those of Ag （2.669 μg·L^-1）, Mo （0.559 μg·L^-1） and Sn （0.325 μg·L^-1） were respectively noted in Foire channel, Naviundu river under bridge on Kasenga road and Kalulako river. The concentrations of Cd in Naviundu river at Cimenkat exit （11.358 μg·L^-1）, Chemaf bydrometallurgical plant effluent （9.697μg·L^-1）, Naviundu river under bridge on De Plaines Avenue （6.95 μg·L^-1） and Kalulako river （3.229 μg·L^-1）, Pb concentrations in Chemaf hydrometallurgical plant effluent （472.287 μg·L^-1） as well as the AI, Fe and Mn concentrations recorded in most waters in this study exceeded the WHO （World Health Organization） maximum permissible limits for drinking water. The metal contamination of waters of the studied rivers, channel and spring might be partially attributed to natural processes, unplanned urbanization and poor waste management, and mostly to abandoned and ongoing mining and ore processing activities in Lubumbashi city.
文摘Concentrations of fifteen trace metals including Aluminum （Al）, Vanadium （V）, Chromium （Cr）, Manganese （Mn）, Iron （Fe）, Strontium （Sr）, Molybdenum （Mo）, Silver （Ag）, Cadmium （Cd）, Tin （Sn）, Caesium （Cs）, Barium （Ba）, Lead （Pb）, Bismuth （Bi） and Uranium （U） were investigated in water samples collected from sixteen sampling locations in the Lubumbashi river basin and five locations in Kafubu, Kimilolo and Kinkalabwamba rivers during February, March and April 2016. Chemical analyses of the samples were carried out using ICP-MS （Inductively Coupled Plasma-Mass Spectrometer）. Water pH was determined using a pH-meter and pH values ranged from 4.2 to 7.8. The highest mean trace metal levels of water were 5,515.816 ）μg·L^-1, 166.925μg·L^-1, 3.898μg·L^-1 and 1.879μg·L^-1 for Al, Ba, Cr and U, respectively in Kashobwe river, 2,419.522 μg·L^-1 and 17.994 μg·L^-1 for Fe and Cd, respectively in Kafubu river at its confluence with Lubumbashi rivers, 1,408.136μg·L^-1 for Mn in Kafubu river 1.36 kilometer downward its confluence with Naviundu river, 222.406 μg·L^-1 and 0.092 μg·L^-1 for Sr and Cs, respectively in Kamalondo river 60 meters from the GCM-Lubumbashi （General of Quarries and Mines-Lubumbashi） smelter, 140.294μg·L^-1, 12.063 μg·L^-1 and 0.008μg·L^-1 for Pb, V and Bi, respectively in Munua river, 3.544 μg·L^-1 for Ag in Kabulameshi river, 1.49 μg·L^-1 for Mo in Kafubu river and 0.081μg·L^-1 for Sn in Tshondo river. The mean concentrations of Al, Cd, Fe, Mn and Pb in water of many rivers and the channel exceeded the maximum admissible limits of the WHO （World Health Organization）, USEPA （United States Environmental Protection Agency） and EU （European Union） drinking-water standards. Trace metal contamination of water of the studied rivers, channel and springs might be partially attributed to natural processes, unplanned urbanization, poor waste management and mostly to abandoned and ongoing mining and ore processing activities in Lubumbashi city.
基金Supported by the National High Technology Research and Development Programme of China(No.2007AA04Z340)
文摘A simple autonomous docking method based on infrared sensors for mobile self-reconfigurable relay microrobots is proposed in the paper.The IR guidance system composed of an IR receiver and four IR emitters is designed,analyzed and developed.The autonomous docking control method based on centering alignment and dynamic motion planning is adopted so that it has high efficiency and reliability.Two basic microrobot prototypes are developed,and related docking experiments are done to verify the feasibility of the approach.
文摘As described in this paper, we propose a new haptic interface for a service robot. For safety with service robots working in a space where people live, some notification before collision with an obstacle is desirable. To achieve such a function, we developed a master-slave manipulator system in which the slave manipulator surface is covered with many proximity sensors. Additionally, we developed a haptic device that feeds back proximity sense information to the operator using small vibration motors. We attached the haptic device to the arm of the operator and vibrated the vibration motor corresponding to the sensor. Thereby, the operator was able to ascertain the position of an object near the manipulator, and to make the robot maneuver to avoid it before collision. To confirm the system usefulness, we equipped subjects with the developed proximity sense presentation device and performed a detection-position-specific experiment and an obstacle avoidance experiment in a narrow space. As results of the detection position specific experiment on five subjects, four subjects reported the detection position correctly. The remaining one person failed because of his particular arm shape. Operation experiments conducted in a narrow space showed that all subjects＇ work was successful when given feedback of proximity sense information. Nobody was successful without proximity sense information. Results of these two experiments demonstrate that this proposed system is useful for obstacle avoidance of a master-slave manipulator system.
基金supported by the National Natural Science Foundation of China(30770701)the Fundamental Research Funds for the Central Universities(GK201302052,GK261001007)
文摘Many receptors,including thermal receptors and mechanical receptors,are only activated by stimuli within a clearly defined range of intensities.Differences in the receptive ranges enable individual receptors and their sensory centers to precisely detect the intensity of the stimulus and changes in intensity.Baroreceptors are the sensory terminals of the baroreflex.It is well understood that an increasing number of baroreceptors are recruited to produce afferent action potentials as the blood pressure increases,indicating that individual baroreceptors have different pressure thresholds.The present study revealed that individual baroreceptors could stop their afferent signals when the blood pressure exceeds a certain level,indicating that individual baroreceptors are sensitive to a specific range of blood pressure.The receptive ranges of individual baroreceptors differ in terms of the total range,the lower threshold,and the upper threshold.Of 85 baroreceptors examined in this study,the upper thresholds for about half were within the physiological blood pressure range.These results indicate that supraphysiological blood pressure is unlikely to be encoded by the recruitment of more baroreceptors.Instead,supraphysiological blood pressure levels might be signaled by an increase in the frequency of action potentials or by other mechanisms.In conclusion,our results indicate that rabbit baroreceptors are activated by blood pressure levels within specific receptive ranges.These findings should encourage further studies to examine the role of population coding of blood pressure by baroreceptors in the baroreflex.
