The hot tearing susceptibility of MgZn2.5YxZr0.5 (x=0.5, 1, 2, 4, 6) alloys was evaluated by thermodynamic calculations based on Clyne-Davies model. The microstructure and morphology of hot tearing regions of the al...The hot tearing susceptibility of MgZn2.5YxZr0.5 (x=0.5, 1, 2, 4, 6) alloys was evaluated by thermodynamic calculations based on Clyne-Davies model. The microstructure and morphology of hot tearing regions of the alloys were observed by X-ray diffraction and scanning electron microscopy. The solidification temperature and shrinkage stress during the solidification of MgZn2.5YxZr0.5 alloys in the“T”type hot tearing permanent-mold were acquired with the attached computer. The effect factors of hot tearing susceptibility of MgZn2.5YxZr0.5 alloys, such as the solidification temperature interval, the variation of solid fraction in vulnerable region, the residual liquid fraction in the final stage, the type of the second phase of the alloys were discussed based on the above calculation and observation. The results demonstrated that the hot tearing susceptibility in the investigated alloys was found as follows:MgZn2.5Y2Zr0.5>MgZn2.5Y0.5Zr0.5>MgZn2.5Y4Zr0.5>MgZn2.5Y6Zr0.5>MgZn2.5Y1Zr0.5. The highest hot tearing susceptibility of MgZn2.5Y2Zr0.5 alloy related to the following reasons: the largest freezing range, the biggest changing of the variation of solid fraction in vulnerable region, the least liquid film in the final stage of solidification, the formation of the second phase which worsens the liquid flow and interdendritic feeding after dendrite coherency.展开更多
An intelligent emergency service( IES) system is designed for indoor environments based on a wireless sensor and actuator network( WSAN) composed of a gateway, sensor nodes, and a multi-robot system( MRS). If th...An intelligent emergency service( IES) system is designed for indoor environments based on a wireless sensor and actuator network( WSAN) composed of a gateway, sensor nodes, and a multi-robot system( MRS). If the MRS receives accident alarm information, the group of robots will navigate to the accident sites and provide corresponding emergency services.According to the characteristics of the MRS, a distributed consensus formation protocol is designed, which can assure that the multiple robots arrive at the accident site in a specified formation. The prototype emergency service system was designed and implemented, and some relevant simulations and experiments were carried out. The results showthat the MRS can successfully provide emergency lighting and failure node replacement services when accidents happen. The effectiveness of the algorithm and the feasibility of the system are verified.展开更多
Tripchlorolide (TC) is a potent antitumor reagent purified from a Chinese herb Tripterygium Wilfordii Hook. f.. However, its cellular effects and mechanism of action are unknown. We showed here that TC induced apoptos...Tripchlorolide (TC) is a potent antitumor reagent purified from a Chinese herb Tripterygium Wilfordii Hook. f.. However, its cellular effects and mechanism of action are unknown. We showed here that TC induced apoptosis of Chinese Hamster Ovary (CHO) cells in time- and dose-dependent manners. TC resulted in the degradation of Bcl-2, the translocation of Bax from the cytosol to mitochondria, and the release of cytochrome c from mitochondria. Stable overexpression of human Bcl-2 could reduce the apoptosis of TCtreated cells by blocking the translocation of Bax and the release of cytochrome c. These results indicate that TC induces apoptosis of CHO cell by activating the mitochondrion-mediated apoptotic pathway involving the proteins of Bcl-2 family and cytochrome c.展开更多
In order to improve the thrust-power ratio index of the linear induction motor(LIM), a novel adaptive genetic algorithm (NAGA) is proposed for the design optimization of the LIM. A good-point set theory that helps...In order to improve the thrust-power ratio index of the linear induction motor(LIM), a novel adaptive genetic algorithm (NAGA) is proposed for the design optimization of the LIM. A good-point set theory that helps to produce a uniform initial population is used to enhance the optimization efficiency of the genetic algorithm. The crossover and mutation probabilities are improved by using the function of sigmoid and they can be adjusted nonlinearly between average fitness and maximal fitness with individual fitness. Based on the analyses of different structures between the LIM and the rotary induction motor (RIM) and referring to the analysis method of the RIM, the steady-state characteristics of the LIM that considers the end effects of the LIM is calculated and the optimal design model of the thrust-power ratio index is also presented. Through the comparison between the optimal scheme and the old scheme, the thrust-power ratio index of the LIM is obviously increased and the validity of the NAGA is proved.展开更多
A filtering algorithm and direction identification method are presented for the positioning system of the mid-speed maglev train. Considering the special structure of the mid-speed maglev train, the ground position es...A filtering algorithm and direction identification method are presented for the positioning system of the mid-speed maglev train. Considering the special structure of the mid-speed maglev train, the ground position estimation method is adopted for its traction system. As the train is running, the induction loop-cable receives the signal sent by the on-board antenna to detect the position and direction of the train. But the height of the on-board antenna relative to the loop-cable is highly vulnerable to the change of the suspension height and the magnetic field produced by the traction during traveling, which may lead to amplitude fluctuation of the received signal. Consequently, the position estimation may be inaccurate. Therefore, a discrete second-order nonlinear trackdifferentiator is proposed based on the boundary characteristic curves, and the new differentiator could also extract the running direction of the train for the traction system. The experimental results show that the tracking differentiator can effectively filter out the signal interference and can provide accurate direction signal.展开更多
Polypeptide from Chlamys farreri (PCF) , a topical polypeptide isolated from Chlamys farreri , was used in this experiment aimed to investigate the photoprotective effect of PCF against chronic skin damage induced by ...Polypeptide from Chlamys farreri (PCF) , a topical polypeptide isolated from Chlamys farreri , was used in this experiment aimed to investigate the photoprotective effect of PCF against chronic skin damage induced by ultraviolet A (UVA) and ultraviolet B (UVB) radiation. The chronic ultraviolet irradiated guinea pig model was established, and visible changes in the skin including wrinkling, sagging and erythema were observed. Malondialdehyde (MDA) and antioxidant enzymes including superoxide dismutase (SOD) and glutathione peroxidase (GSH px) in the dorsal skin were determined using biochemical methods. The results showed:(1)PCF (5 % and 20%) could greatly protect the dorsal skin of guinea pig against wrinkling, sagging and erythema induced by UV radiation in a concentration dependent manner.(2)PCF could reduce MDA formation in the dorsal skin caused by UV irradiation, while increasing the activities of SOD and GSH px.(3)The differences among the PCF groups and UV model group were significant ( P <0.05, P <0.01). These results indicated that topical application of PCF provided broad solar UV spectrum photoprotection; and that the antioxidant property of PCF might play a role in photoprotection.展开更多
This paper addresses the bearingless motor with a single set of multiphase windings. The interaction between M and M±1 pole-pair magnetic fields produces radial force. Based on this principle,a bearingless machin...This paper addresses the bearingless motor with a single set of multiphase windings. The interaction between M and M±1 pole-pair magnetic fields produces radial force. Based on this principle,a bearingless machine is obtained. Conventional bearingless machine has dual windings,levitation windings and torque windings,which produce the two magnetic fields. In the proposed bearingless motor,the two needed magnetic fields are produced by feeding two groups of currents to a single set of multiphase windings. Taking a 5-phase induction motor as example,the inductance matrices,considering air gap eccentricity,are calculated with the modified winding function method. The radial force analytical model is deduced by virtual displacement,and its results are validated by FEA. The mathematical model of the new bearingless machine is set up,and the simulation results verified the feasibility of this novel bearingless motor.展开更多
Magnetic induction tomography(MIT) is one of the newest industrial process imaging techniques.Main industrial applications of the MIT imaging are in high conductive flow imaging.However,recently it has been shown that...Magnetic induction tomography(MIT) is one of the newest industrial process imaging techniques.Main industrial applications of the MIT imaging are in high conductive flow imaging.However,recently it has been shown that the MIT may be useful for low conductive process imaging.This paper presents a cost effective hardware design for MIT in industrial applications,called Bath-MKI industrial MIT system.The system comprises 8 inductor coils and has the possibility of expansion to 16 coils.The excitation signals and the measured voltages are generated and measured using a LabView based system.Two 16 by 1 multiplexers are used to select between the coils.Measurements,excitation and multiplexing are all controlled by a National Instrument(NI) USB based DAQ:USB-6259 and a signal generator.Using the same electronics,the prototype is tested with two different coil arrays;one is a small scale ferrite core coil and one larger scale air cored coil.Experimental image reconstruction results are shown using both small scale and large scale coil arrays.展开更多
A single channel measurement system for brain MIT has been built. The system is composed of an exciting source unit,a detecting unit,a rotating and controlling unit,and imaging unit. The experiment results of single c...A single channel measurement system for brain MIT has been built. The system is composed of an exciting source unit,a detecting unit,a rotating and controlling unit,and imaging unit. The experiment results of single channel measurements show that the system output versus the conductivity of the objects was an approximate linear relationship when the diameter of an object was about 9cm and its conductivity was in 0.1 S/m,0.7 S/m,2 S/m,6 S/m. The sensitivit yof the phase detector was 53 mV/degree from -10 to +10 degree.展开更多
The paper deals with a new model of linear induction motor (LIM) to improve the reliability of the system. Based on the normal equation circuit of LIM considering the dynamic end effect, an equivalent circuit model wi...The paper deals with a new model of linear induction motor (LIM) to improve the reliability of the system. Based on the normal equation circuit of LIM considering the dynamic end effect, an equivalent circuit model with compensation of large end effect is constructed when the end effect force at synchronism is of braking character. The equivalent circuit model is used for secondary-flux oriented control of LIM. Single neuron network PI unit for LIM servo-drive is also discussed. The effectiveness of mathematical model for drive control is verified by simulations.展开更多
For the test of rotation speed of high spinning projectile, the general formula of the motional electromotive force (MEMF) of planar magnetic induction coil (PMIC) is derived in case of 3D rotation in a stable mag...For the test of rotation speed of high spinning projectile, the general formula of the motional electromotive force (MEMF) of planar magnetic induction coil (PMIC) is derived in case of 3D rotation in a stable magnetic field. Under a reasona-ble assumption, the MEMF of PMIC is simplified after the aforementioned general formula is used to calculate high spinning PMIC in the geomagnetic field environment. The determination approach of half-cycle is discussed and the method of rotation speed test is studied, and a test is conducted in the paper. The rotation speed curve obtained by the approach in this paper is consistent with the curve by telemetry.展开更多
The collected spectrum of the fiber Bragg grating(FBG) and the loss of the detected optical power are discussed with respect to the 3-dB bandwidth of a Fabry-Perot(F-P) type tunable optical filter(TOF),respectively.An...The collected spectrum of the fiber Bragg grating(FBG) and the loss of the detected optical power are discussed with respect to the 3-dB bandwidth of a Fabry-Perot(F-P) type tunable optical filter(TOF),respectively.And the optimized parameters of the TOF are obtained consequently.It is demonstrated that the relationship between the transmission wave-length of the TOF and its drive voltage is nonlinear.A new method to compensate the nonlinearity of the TOF is proposed.The linear sweeping of the transmission wavelength of the TOF is achieved through modifying the drive voltage using interpolation algorithm.It is observed that the average error and the maximum error of the transmission wavelength are reduced sharply under linear fit.The dynamic strain sensing is realized by use of a reference FBG and moving averaging algorithm in this system.展开更多
We propose a numerical solution of Faraday's law of induction based on the knowledge of the time-varying, non-uniform vector potential inside arbitrarily shaped electrical coils. The vector potential can be related t...We propose a numerical solution of Faraday's law of induction based on the knowledge of the time-varying, non-uniform vector potential inside arbitrarily shaped electrical coils. The vector potential can be related to the magnetic induction which yields the well-known form of Faraday's law. The algorithm applies for non-retarding fields within the quasi-stationary regime. The model is intended to help to understand the behavior of electromagnetic fields inside the discharge chambers of radio-frequency ion thrusters. This provides a basis for modeling an inductively-coupled plasma which is kept burning by absorbing electromagnetic energy. In the long run, this plasma model will be used to support development processes of electric and electronic control devices which are needed for driving radio-frequency ion thrusters more efficiently. To predict the induced radio frequency fields more precisely, the skin effect along the coil wire is modeled. Furthermore, an impedance model of the coil, which incorporates the skin effect, is introduced. The simulated data are compared to measured values obtained by a generic electric field probe. Although the probe was uncalibrated, the observed values were highly similar to the expected values as determined by the numerical solution.展开更多
基金Project (2011BAE22B01) supported by the National Key Technologies R&D Program,ChinaProject (2013CB632203) supported by the National Basic Research Program of China
文摘The hot tearing susceptibility of MgZn2.5YxZr0.5 (x=0.5, 1, 2, 4, 6) alloys was evaluated by thermodynamic calculations based on Clyne-Davies model. The microstructure and morphology of hot tearing regions of the alloys were observed by X-ray diffraction and scanning electron microscopy. The solidification temperature and shrinkage stress during the solidification of MgZn2.5YxZr0.5 alloys in the“T”type hot tearing permanent-mold were acquired with the attached computer. The effect factors of hot tearing susceptibility of MgZn2.5YxZr0.5 alloys, such as the solidification temperature interval, the variation of solid fraction in vulnerable region, the residual liquid fraction in the final stage, the type of the second phase of the alloys were discussed based on the above calculation and observation. The results demonstrated that the hot tearing susceptibility in the investigated alloys was found as follows:MgZn2.5Y2Zr0.5&gt;MgZn2.5Y0.5Zr0.5&gt;MgZn2.5Y4Zr0.5&gt;MgZn2.5Y6Zr0.5&gt;MgZn2.5Y1Zr0.5. The highest hot tearing susceptibility of MgZn2.5Y2Zr0.5 alloy related to the following reasons: the largest freezing range, the biggest changing of the variation of solid fraction in vulnerable region, the least liquid film in the final stage of solidification, the formation of the second phase which worsens the liquid flow and interdendritic feeding after dendrite coherency.
基金The National Natural Science Foundation of China(No.61375076)the Research&Innovation Program for Graduate Student in Universities of Jiangsu Province(No.KYLX_0108)+1 种基金the Scientific Research Foundation of Graduate School of Southeast University(No.YBJJ1423)Jiangsu Planned Projects for Postdoctoral Research Funds(No.1302064B)
文摘An intelligent emergency service( IES) system is designed for indoor environments based on a wireless sensor and actuator network( WSAN) composed of a gateway, sensor nodes, and a multi-robot system( MRS). If the MRS receives accident alarm information, the group of robots will navigate to the accident sites and provide corresponding emergency services.According to the characteristics of the MRS, a distributed consensus formation protocol is designed, which can assure that the multiple robots arrive at the accident site in a specified formation. The prototype emergency service system was designed and implemented, and some relevant simulations and experiments were carried out. The results showthat the MRS can successfully provide emergency lighting and failure node replacement services when accidents happen. The effectiveness of the algorithm and the feasibility of the system are verified.
基金supported by Grant 39825115 of the National Outstanding Young Scientists,a special grant of major state basic research program of China(No.G1999053901)a grant from the Chinese Academy of Sciences KSCX2-SW-203 to JR Wu.
文摘Tripchlorolide (TC) is a potent antitumor reagent purified from a Chinese herb Tripterygium Wilfordii Hook. f.. However, its cellular effects and mechanism of action are unknown. We showed here that TC induced apoptosis of Chinese Hamster Ovary (CHO) cells in time- and dose-dependent manners. TC resulted in the degradation of Bcl-2, the translocation of Bax from the cytosol to mitochondria, and the release of cytochrome c from mitochondria. Stable overexpression of human Bcl-2 could reduce the apoptosis of TCtreated cells by blocking the translocation of Bax and the release of cytochrome c. These results indicate that TC induces apoptosis of CHO cell by activating the mitochondrion-mediated apoptotic pathway involving the proteins of Bcl-2 family and cytochrome c.
文摘In order to improve the thrust-power ratio index of the linear induction motor(LIM), a novel adaptive genetic algorithm (NAGA) is proposed for the design optimization of the LIM. A good-point set theory that helps to produce a uniform initial population is used to enhance the optimization efficiency of the genetic algorithm. The crossover and mutation probabilities are improved by using the function of sigmoid and they can be adjusted nonlinearly between average fitness and maximal fitness with individual fitness. Based on the analyses of different structures between the LIM and the rotary induction motor (RIM) and referring to the analysis method of the RIM, the steady-state characteristics of the LIM that considers the end effects of the LIM is calculated and the optimal design model of the thrust-power ratio index is also presented. Through the comparison between the optimal scheme and the old scheme, the thrust-power ratio index of the LIM is obviously increased and the validity of the NAGA is proved.
基金Project(11226144) supported by the National Natural Science Foundation of China
文摘A filtering algorithm and direction identification method are presented for the positioning system of the mid-speed maglev train. Considering the special structure of the mid-speed maglev train, the ground position estimation method is adopted for its traction system. As the train is running, the induction loop-cable receives the signal sent by the on-board antenna to detect the position and direction of the train. But the height of the on-board antenna relative to the loop-cable is highly vulnerable to the change of the suspension height and the magnetic field produced by the traction during traveling, which may lead to amplitude fluctuation of the received signal. Consequently, the position estimation may be inaccurate. Therefore, a discrete second-order nonlinear trackdifferentiator is proposed based on the boundary characteristic curves, and the new differentiator could also extract the running direction of the train for the traction system. The experimental results show that the tracking differentiator can effectively filter out the signal interference and can provide accurate direction signal.
文摘Polypeptide from Chlamys farreri (PCF) , a topical polypeptide isolated from Chlamys farreri , was used in this experiment aimed to investigate the photoprotective effect of PCF against chronic skin damage induced by ultraviolet A (UVA) and ultraviolet B (UVB) radiation. The chronic ultraviolet irradiated guinea pig model was established, and visible changes in the skin including wrinkling, sagging and erythema were observed. Malondialdehyde (MDA) and antioxidant enzymes including superoxide dismutase (SOD) and glutathione peroxidase (GSH px) in the dorsal skin were determined using biochemical methods. The results showed:(1)PCF (5 % and 20%) could greatly protect the dorsal skin of guinea pig against wrinkling, sagging and erythema induced by UV radiation in a concentration dependent manner.(2)PCF could reduce MDA formation in the dorsal skin caused by UV irradiation, while increasing the activities of SOD and GSH px.(3)The differences among the PCF groups and UV model group were significant ( P <0.05, P <0.01). These results indicated that topical application of PCF provided broad solar UV spectrum photoprotection; and that the antioxidant property of PCF might play a role in photoprotection.
基金Project (No. 50677060) supported by the National Natural ScienceFoundation of China
文摘This paper addresses the bearingless motor with a single set of multiphase windings. The interaction between M and M±1 pole-pair magnetic fields produces radial force. Based on this principle,a bearingless machine is obtained. Conventional bearingless machine has dual windings,levitation windings and torque windings,which produce the two magnetic fields. In the proposed bearingless motor,the two needed magnetic fields are produced by feeding two groups of currents to a single set of multiphase windings. Taking a 5-phase induction motor as example,the inductance matrices,considering air gap eccentricity,are calculated with the modified winding function method. The radial force analytical model is deduced by virtual displacement,and its results are validated by FEA. The mathematical model of the new bearingless machine is set up,and the simulation results verified the feasibility of this novel bearingless motor.
文摘Magnetic induction tomography(MIT) is one of the newest industrial process imaging techniques.Main industrial applications of the MIT imaging are in high conductive flow imaging.However,recently it has been shown that the MIT may be useful for low conductive process imaging.This paper presents a cost effective hardware design for MIT in industrial applications,called Bath-MKI industrial MIT system.The system comprises 8 inductor coils and has the possibility of expansion to 16 coils.The excitation signals and the measured voltages are generated and measured using a LabView based system.Two 16 by 1 multiplexers are used to select between the coils.Measurements,excitation and multiplexing are all controlled by a National Instrument(NI) USB based DAQ:USB-6259 and a signal generator.Using the same electronics,the prototype is tested with two different coil arrays;one is a small scale ferrite core coil and one larger scale air cored coil.Experimental image reconstruction results are shown using both small scale and large scale coil arrays.
文摘A single channel measurement system for brain MIT has been built. The system is composed of an exciting source unit,a detecting unit,a rotating and controlling unit,and imaging unit. The experiment results of single channel measurements show that the system output versus the conductivity of the objects was an approximate linear relationship when the diameter of an object was about 9cm and its conductivity was in 0.1 S/m,0.7 S/m,2 S/m,6 S/m. The sensitivit yof the phase detector was 53 mV/degree from -10 to +10 degree.
基金Project supported by the National Natural Science Foundation of China (No. 50477030) the Natural Science Foundation of Zheji-ang Province (No. Y105351), China
文摘The paper deals with a new model of linear induction motor (LIM) to improve the reliability of the system. Based on the normal equation circuit of LIM considering the dynamic end effect, an equivalent circuit model with compensation of large end effect is constructed when the end effect force at synchronism is of braking character. The equivalent circuit model is used for secondary-flux oriented control of LIM. Single neuron network PI unit for LIM servo-drive is also discussed. The effectiveness of mathematical model for drive control is verified by simulations.
基金National Key Lab for Electronic Measurement and Technology,North University of China(No.9140C120401080C12)
文摘For the test of rotation speed of high spinning projectile, the general formula of the motional electromotive force (MEMF) of planar magnetic induction coil (PMIC) is derived in case of 3D rotation in a stable magnetic field. Under a reasona-ble assumption, the MEMF of PMIC is simplified after the aforementioned general formula is used to calculate high spinning PMIC in the geomagnetic field environment. The determination approach of half-cycle is discussed and the method of rotation speed test is studied, and a test is conducted in the paper. The rotation speed curve obtained by the approach in this paper is consistent with the curve by telemetry.
基金the National Natural Science Foundation of China (Contact No. 60577013)the New Cen-tury Support Program for Talented Young Teachers in Universities of Ministry of Education, China
文摘The collected spectrum of the fiber Bragg grating(FBG) and the loss of the detected optical power are discussed with respect to the 3-dB bandwidth of a Fabry-Perot(F-P) type tunable optical filter(TOF),respectively.And the optimized parameters of the TOF are obtained consequently.It is demonstrated that the relationship between the transmission wave-length of the TOF and its drive voltage is nonlinear.A new method to compensate the nonlinearity of the TOF is proposed.The linear sweeping of the transmission wavelength of the TOF is achieved through modifying the drive voltage using interpolation algorithm.It is observed that the average error and the maximum error of the transmission wavelength are reduced sharply under linear fit.The dynamic strain sensing is realized by use of a reference FBG and moving averaging algorithm in this system.
文摘We propose a numerical solution of Faraday's law of induction based on the knowledge of the time-varying, non-uniform vector potential inside arbitrarily shaped electrical coils. The vector potential can be related to the magnetic induction which yields the well-known form of Faraday's law. The algorithm applies for non-retarding fields within the quasi-stationary regime. The model is intended to help to understand the behavior of electromagnetic fields inside the discharge chambers of radio-frequency ion thrusters. This provides a basis for modeling an inductively-coupled plasma which is kept burning by absorbing electromagnetic energy. In the long run, this plasma model will be used to support development processes of electric and electronic control devices which are needed for driving radio-frequency ion thrusters more efficiently. To predict the induced radio frequency fields more precisely, the skin effect along the coil wire is modeled. Furthermore, an impedance model of the coil, which incorporates the skin effect, is introduced. The simulated data are compared to measured values obtained by a generic electric field probe. Although the probe was uncalibrated, the observed values were highly similar to the expected values as determined by the numerical solution.