Eased on the mechanism of temperature tactile sensing of human finger,a heat flux tactile sensor com- posed of a thermostat module and a heat flux sensor is designed to identify material thermal properties. The ther- ...Eased on the mechanism of temperature tactile sensing of human finger,a heat flux tactile sensor com- posed of a thermostat module and a heat flux sensor is designed to identify material thermal properties. The ther- mostat module maintains the sensor temperature invariable, and the heat flux sensor(Peltier device) detects the heat flux temperature difference between the thermostat module and the object surface. Two different modes of the heat flux tactile sensor are proposed, and they are simulated and experimented for different material objects. The results indicate that the heat flux tactile sensor can effectively identify different thermal properties.展开更多
This paper presents a new designed miniature six DOF (degree of freedom) force/torque sensor. This sensor is fully integrated with a micro DSP (digital signal processor), so all the signal conditioning, A/D, decou...This paper presents a new designed miniature six DOF (degree of freedom) force/torque sensor. This sensor is fully integrated with a micro DSP (digital signal processor), so all the signal conditioning, A/D, decoupling, digital-signals serial output are performed in the sensor. Some experimental results are presented to demonstrate the capability of the proposed design. Finally, a neural network was used for decoupling the interacting signals, compared with the conventional method using the inverse matrix, this new method is more accurate.展开更多
The main problem in an efficient Zn(CH3COO)2/AC (AC-activated carbon) catalyst preparation is the achievement of uniform distribution of highly dispersed salt component on the activated carbon (AC) surface. The ...The main problem in an efficient Zn(CH3COO)2/AC (AC-activated carbon) catalyst preparation is the achievement of uniform distribution of highly dispersed salt component on the activated carbon (AC) surface. The solution of this problem is modification of the AC by hydrogen peroxide (H202) oxidation of the surface and treatment of AC with acetic acid as well as special methods of salt deposition and catalyst drying. The investigations of these ways of AC surface modification (treatment of AC with acetic acid and H2O2) have demonstrated the obtained AC to have both an increased adsorption capacity as to Zn(OAc)2 and optimum volumes of meso- and micro-pores as well as high catalyst activity in vinyl acetate (VA) synthesis. The characteristics of supports and catalysts were found out by benzene, water and acetic acid vapors adsorption. The distribution of the salt on the AC surface was studied by small-angle X-ray scattering (SAXS), by scanning electron microscopy (SEM) and X-ray micro-analysis (XMA). The catalysts were tested in vinyl acetate synthesis in flow-bed isothermal reactor by cyclic method at 175, 205 and 230℃.展开更多
A new kind of inertial piezoelectric actuator for a micro in-pipe robot is proposed and studied. The actuator is composed of a body, corresponding to a mass rod, and four elastic legs. Each leg is a composite piezoele...A new kind of inertial piezoelectric actuator for a micro in-pipe robot is proposed and studied. The actuator is composed of a body, corresponding to a mass rod, and four elastic legs. Each leg is a composite piezoelectric bimorph beam, made up of a middle metal element, an upper and lower piezoelectric elements. The mechanism is driven by an asymmetric waveform voltage, such as saw-toothed waveform, and utilizes the dynamic relationship between the maximum static friction force and the inertial force. To study the actuator, firstly, the constituent equation of a composite piezoelectric bimorph under both applied voltage and external force was inferred by thermodynamics. Secondly, the dvnamic model of the actuator was established analyzing the relationship between the locomotive states, viz. displacement and velocity, and design parameters, such as piezoelectric strain constant, elastic modulus,length, width and thickness of the piezoelectric element, actuator mass, and driving vohage. At last, the dynamic equation was solved and the theoretical calculation of the inherent frequency was more consistent with the experimental data, which proved the rationality of the model. All these lay a theoretical foundation of the micro actuator parameter optimization and more research on a micro robot.展开更多
Microburst is a special kind of low-level wind shear, which may do great damage to aircrafts. Modelling of a microburst is significant for flight simulations. In this paper we adopt multiple vortex ring principle to m...Microburst is a special kind of low-level wind shear, which may do great damage to aircrafts. Modelling of a microburst is significant for flight simulations. In this paper we adopt multiple vortex ring principle to model microburst and propose a new parameter selection method of multiple vortex ring model. We treat the parameters selection as an optimization problem, and introduce the differential evolution algorithm into it. A nested differential evolution algorithm is proposed to complete the two optimization process, objective optimization and intermediate optimization. The simulation results show that this method can flexibly generate microburst with any maximum wind velocity.展开更多
The MOBILE is a logic element realizing the monostable-bistable transition of a circuit that consists of two resonant tunneling transistors—the resonant tunneling diodes (RTDs) connected in series. It has several adv...The MOBILE is a logic element realizing the monostable-bistable transition of a circuit that consists of two resonant tunneling transistors—the resonant tunneling diodes (RTDs) connected in series. It has several advantages including multiple inputs and multiple functions. In this paper, by connecting a heterojunction phototransistor (HPT) with the MOBILE, a novel optoelectronic functional device can be got, which presents the function of both photocurrent switching and photocurrent latching. These behaviors have been demonstrated for the first time by simulating experiments and circuit simulations, with RTDs firstly manufactured in China. Research indicates that the novel photo-controlled MOBILE has the same logic functions as conventional electrical MOBILE except for with light as an input signal.展开更多
A general multiple-loop feedback approach for realization of Four-Terminal Floating Nullor RC(FTFN-RC) filter is presented.The proposed filter is constructed by multi-output FTFNs, capacitors and resistors.It can simu...A general multiple-loop feedback approach for realization of Four-Terminal Floating Nullor RC(FTFN-RC) filter is presented.The proposed filter is constructed by multi-output FTFNs, capacitors and resistors.It can simultaneously realize slow-pass, band-pass(if order is even number), and high-pass filter responses.With RC elements grounded and requiring no component matching con-straints, it is fully integrated conveniently.Simulations are performed for the fourth-order Butterworth filter to verify the validity of the circuit.展开更多
Temperature sensitivity is greatly improved by taking the following three measures: proper long-period fiber grating (LPFG) whose strain coefficient of the core is larger than that of the cladding is employed, the ...Temperature sensitivity is greatly improved by taking the following three measures: proper long-period fiber grating (LPFG) whose strain coefficient of the core is larger than that of the cladding is employed, the LPFG is coated with a thin film of the material whose refractive index decreases with the temperature, and the sensor is encapsulated by metal material whose thermal expansion coefficient is large. By computer simulation, a measured temperature coefficient of 0.2375 nm/℃ and a temperature resolution less than 0.1 ℃ are obtained.展开更多
In conventional source-filter models, voiced and unvoiced components were considered independently. However, in practice it was difficult to separate the source into two parts. An actual source consists of a mixture o...In conventional source-filter models, voiced and unvoiced components were considered independently. However, in practice it was difficult to separate the source into two parts. An actual source consists of a mixture of two sources and the ratio varies according to the content or the intention of speaker. It had been investigated to separate the voiced and unvoiced components for different source models. Source signals were modeled based on the residual signal measured from inverse filtering. Three different source models were assumed. The parameters of each model were optimized for the original speech signal using a genetic algorithm. The resulting parameters were compared in terms of the mel-cepstral distance to the original signal, the spectrogram and the spectral envelope from the synthesized signal. The optimization method achieves an improvement of 15% for the Klatt model, but there is little improvement in the modified residual case.展开更多
The tunable microwave photonic filter based on a fiber ring and erbium-doped fiber amplifier (EDFA) was proposed. By introducing a section of erbium-doped fiber (EDF) into the fiber ring, the loss of the signal ca...The tunable microwave photonic filter based on a fiber ring and erbium-doped fiber amplifier (EDFA) was proposed. By introducing a section of erbium-doped fiber (EDF) into the fiber ring, the loss of the signal can be compensated by the EDFA gain through adjusting the pump power. This can largely increase the number of the effective sampling taps, and then improve the performance of the microwave photonic filter notably. When the pump power was set to be 42.7 roW, a microwave bandpass filter with the 3-dB bandwidth of 0.15 MHz, the Q factor up to 100 and extinction ratio up to 20 dB was achieved. By employing a tunable optical delay line in the above fiber ring, a tunable microwave photonic filter has been realized through tuning the length of the optical delay line. The proposed tunable microwave photonic filter can fred great applications in microwave signal processing and ROF system.展开更多
The use of ultrasonic sensors has varied applications, but the sensor operation frequency limits the operating distance. An easy way to increase this distance is to couple a mechanical element (horn), but it is nece...The use of ultrasonic sensors has varied applications, but the sensor operation frequency limits the operating distance. An easy way to increase this distance is to couple a mechanical element (horn), but it is necessary to characterize this technique. In this paper the results obtained in a study of the behaviour of mechanical elements coupled to an ultrasonic sensor using finite element techniques are presented. These results have been obtained using Comsol Multiphysics modelling. Also, the effect caused by the sensor size on the radiation acoustic pressure has also been evaluated. In other way, in this paper it is presented the results obtained in the laboratory measurements. First, it is studied the influence of a straight horn attached to the ultrasonic sensor. Later, it is presented the variation in the sound pressure on the radiation axis when the sensor varies its size. In the final part of the paper, the experimental validation of the simulations is presented.展开更多
A new hybrid WDM/TDM passive optical network (PON) implemented by using all-optical wavelength converters (AOWCs) is proposed. The AOWCs are based on the cross-gain modulation (XGM) effect of the semiconductor o...A new hybrid WDM/TDM passive optical network (PON) implemented by using all-optical wavelength converters (AOWCs) is proposed. The AOWCs are based on the cross-gain modulation (XGM) effect of the semiconductor optical amplifier (SOA). Moreover, the feasibility of this sys- tem is experimentally demonstrated by evaluating the impacts of the optical wavelength conversion, time domain waveforms, eye diagrams and bit-error-rate (BER) in AOWC. The results show that the proposal will be a promising solution for the next generation access networks.展开更多
An improved encapsulation method of a sensing element for a cement-based piezoelectric sensor used in civil engineering structure was developed and some tests were carried out for validating this method. The cement-ba...An improved encapsulation method of a sensing element for a cement-based piezoelectric sensor used in civil engineering structure was developed and some tests were carried out for validating this method. The cement-based piezoelectric sensor of this kind is mainly used in concrete structure due to its compatibility with concrete, and the encapsulation method of its sensing element is important to the effectiveness and accuracy of the transfer of the stress from concrete to the sensing element. The sensor′s measurement error of the previous encapsulation method, which was induced by the area of the encapsulation material and the inherent difference of Young′s modulus between cement and encapsulation material, was analyzed theoretically using parallel model. In the improved method, the error is minimized by decreasing the area of the encapsulation material and changing the configuration of the cement and piezoelectric material in the sensor. Two sensors made by the previous and improved methods were embedded in two prisms respectively and the prisms were compressed on Material Test System. Through the comparison of the measurement errors of the two sensors, the improved method was evaluated. The test results show that the improved encapsulation method is effective and feasible.展开更多
基金Supported by the National High Technology Research and Development Program of China(″863″Program)(2009AA01Z314,2009AA01Z311)the Jiangsu Province Natural Science Foundation(BK2009272)theJiangsu Province″333″Program~~
文摘Eased on the mechanism of temperature tactile sensing of human finger,a heat flux tactile sensor com- posed of a thermostat module and a heat flux sensor is designed to identify material thermal properties. The ther- mostat module maintains the sensor temperature invariable, and the heat flux sensor(Peltier device) detects the heat flux temperature difference between the thermostat module and the object surface. Two different modes of the heat flux tactile sensor are proposed, and they are simulated and experimented for different material objects. The results indicate that the heat flux tactile sensor can effectively identify different thermal properties.
基金Supported by the National Natural Science Foundation of China ( No. 60275032 ) and the Supported bv the High Technology Research and Development Programme of China ( No. 2003AA404220).
文摘This paper presents a new designed miniature six DOF (degree of freedom) force/torque sensor. This sensor is fully integrated with a micro DSP (digital signal processor), so all the signal conditioning, A/D, decoupling, digital-signals serial output are performed in the sensor. Some experimental results are presented to demonstrate the capability of the proposed design. Finally, a neural network was used for decoupling the interacting signals, compared with the conventional method using the inverse matrix, this new method is more accurate.
文摘The main problem in an efficient Zn(CH3COO)2/AC (AC-activated carbon) catalyst preparation is the achievement of uniform distribution of highly dispersed salt component on the activated carbon (AC) surface. The solution of this problem is modification of the AC by hydrogen peroxide (H202) oxidation of the surface and treatment of AC with acetic acid as well as special methods of salt deposition and catalyst drying. The investigations of these ways of AC surface modification (treatment of AC with acetic acid and H2O2) have demonstrated the obtained AC to have both an increased adsorption capacity as to Zn(OAc)2 and optimum volumes of meso- and micro-pores as well as high catalyst activity in vinyl acetate (VA) synthesis. The characteristics of supports and catalysts were found out by benzene, water and acetic acid vapors adsorption. The distribution of the salt on the AC surface was studied by small-angle X-ray scattering (SAXS), by scanning electron microscopy (SEM) and X-ray micro-analysis (XMA). The catalysts were tested in vinyl acetate synthesis in flow-bed isothermal reactor by cyclic method at 175, 205 and 230℃.
基金Sponsored by the National Natural Science Foundation of China(Grant No.69774020)the National Doctoral Foundation of China(Grant No.98014106).
文摘A new kind of inertial piezoelectric actuator for a micro in-pipe robot is proposed and studied. The actuator is composed of a body, corresponding to a mass rod, and four elastic legs. Each leg is a composite piezoelectric bimorph beam, made up of a middle metal element, an upper and lower piezoelectric elements. The mechanism is driven by an asymmetric waveform voltage, such as saw-toothed waveform, and utilizes the dynamic relationship between the maximum static friction force and the inertial force. To study the actuator, firstly, the constituent equation of a composite piezoelectric bimorph under both applied voltage and external force was inferred by thermodynamics. Secondly, the dvnamic model of the actuator was established analyzing the relationship between the locomotive states, viz. displacement and velocity, and design parameters, such as piezoelectric strain constant, elastic modulus,length, width and thickness of the piezoelectric element, actuator mass, and driving vohage. At last, the dynamic equation was solved and the theoretical calculation of the inherent frequency was more consistent with the experimental data, which proved the rationality of the model. All these lay a theoretical foundation of the micro actuator parameter optimization and more research on a micro robot.
基金Sponsored by the National Natural Science Foundation of China(Grant No. 61201305)the Heilongjiang Provincial Postdoctoral Foundation(Grant No.LBH-Z11170)the Fundamental Research Funds for the Central Universities(Grant No. HIT. NSRIF. 2012015)
文摘Microburst is a special kind of low-level wind shear, which may do great damage to aircrafts. Modelling of a microburst is significant for flight simulations. In this paper we adopt multiple vortex ring principle to model microburst and propose a new parameter selection method of multiple vortex ring model. We treat the parameters selection as an optimization problem, and introduce the differential evolution algorithm into it. A nested differential evolution algorithm is proposed to complete the two optimization process, objective optimization and intermediate optimization. The simulation results show that this method can flexibly generate microburst with any maximum wind velocity.
文摘The MOBILE is a logic element realizing the monostable-bistable transition of a circuit that consists of two resonant tunneling transistors—the resonant tunneling diodes (RTDs) connected in series. It has several advantages including multiple inputs and multiple functions. In this paper, by connecting a heterojunction phototransistor (HPT) with the MOBILE, a novel optoelectronic functional device can be got, which presents the function of both photocurrent switching and photocurrent latching. These behaviors have been demonstrated for the first time by simulating experiments and circuit simulations, with RTDs firstly manufactured in China. Research indicates that the novel photo-controlled MOBILE has the same logic functions as conventional electrical MOBILE except for with light as an input signal.
基金Supported by the Hunan Province Project of Education Department of Financial Aid (No.04C346)
文摘A general multiple-loop feedback approach for realization of Four-Terminal Floating Nullor RC(FTFN-RC) filter is presented.The proposed filter is constructed by multi-output FTFNs, capacitors and resistors.It can simultaneously realize slow-pass, band-pass(if order is even number), and high-pass filter responses.With RC elements grounded and requiring no component matching con-straints, it is fully integrated conveniently.Simulations are performed for the fourth-order Butterworth filter to verify the validity of the circuit.
基金the Innovation Project of Guangxi Graduate Education Foundation (No.2007106020809M70).
文摘Temperature sensitivity is greatly improved by taking the following three measures: proper long-period fiber grating (LPFG) whose strain coefficient of the core is larger than that of the cladding is employed, the LPFG is coated with a thin film of the material whose refractive index decreases with the temperature, and the sensor is encapsulated by metal material whose thermal expansion coefficient is large. By computer simulation, a measured temperature coefficient of 0.2375 nm/℃ and a temperature resolution less than 0.1 ℃ are obtained.
基金supported by the Second Stage of Brain Korea 21 Projects
文摘In conventional source-filter models, voiced and unvoiced components were considered independently. However, in practice it was difficult to separate the source into two parts. An actual source consists of a mixture of two sources and the ratio varies according to the content or the intention of speaker. It had been investigated to separate the voiced and unvoiced components for different source models. Source signals were modeled based on the residual signal measured from inverse filtering. Three different source models were assumed. The parameters of each model were optimized for the original speech signal using a genetic algorithm. The resulting parameters were compared in terms of the mel-cepstral distance to the original signal, the spectrogram and the spectral envelope from the synthesized signal. The optimization method achieves an improvement of 15% for the Klatt model, but there is little improvement in the modified residual case.
基金supported by the Science Foundation of ZhejiangProvince, China (R104154)
文摘The tunable microwave photonic filter based on a fiber ring and erbium-doped fiber amplifier (EDFA) was proposed. By introducing a section of erbium-doped fiber (EDF) into the fiber ring, the loss of the signal can be compensated by the EDFA gain through adjusting the pump power. This can largely increase the number of the effective sampling taps, and then improve the performance of the microwave photonic filter notably. When the pump power was set to be 42.7 roW, a microwave bandpass filter with the 3-dB bandwidth of 0.15 MHz, the Q factor up to 100 and extinction ratio up to 20 dB was achieved. By employing a tunable optical delay line in the above fiber ring, a tunable microwave photonic filter has been realized through tuning the length of the optical delay line. The proposed tunable microwave photonic filter can fred great applications in microwave signal processing and ROF system.
文摘The use of ultrasonic sensors has varied applications, but the sensor operation frequency limits the operating distance. An easy way to increase this distance is to couple a mechanical element (horn), but it is necessary to characterize this technique. In this paper the results obtained in a study of the behaviour of mechanical elements coupled to an ultrasonic sensor using finite element techniques are presented. These results have been obtained using Comsol Multiphysics modelling. Also, the effect caused by the sensor size on the radiation acoustic pressure has also been evaluated. In other way, in this paper it is presented the results obtained in the laboratory measurements. First, it is studied the influence of a straight horn attached to the ultrasonic sensor. Later, it is presented the variation in the sound pressure on the radiation axis when the sensor varies its size. In the final part of the paper, the experimental validation of the simulations is presented.
文摘A new hybrid WDM/TDM passive optical network (PON) implemented by using all-optical wavelength converters (AOWCs) is proposed. The AOWCs are based on the cross-gain modulation (XGM) effect of the semiconductor optical amplifier (SOA). Moreover, the feasibility of this sys- tem is experimentally demonstrated by evaluating the impacts of the optical wavelength conversion, time domain waveforms, eye diagrams and bit-error-rate (BER) in AOWC. The results show that the proposal will be a promising solution for the next generation access networks.
基金Supported by Hong Kong Research Grant Council to HKUSTunder grant HKUST6212/O2ENational Science Fund forDistinguished Young Scholars of China(No.50425824).
文摘An improved encapsulation method of a sensing element for a cement-based piezoelectric sensor used in civil engineering structure was developed and some tests were carried out for validating this method. The cement-based piezoelectric sensor of this kind is mainly used in concrete structure due to its compatibility with concrete, and the encapsulation method of its sensing element is important to the effectiveness and accuracy of the transfer of the stress from concrete to the sensing element. The sensor′s measurement error of the previous encapsulation method, which was induced by the area of the encapsulation material and the inherent difference of Young′s modulus between cement and encapsulation material, was analyzed theoretically using parallel model. In the improved method, the error is minimized by decreasing the area of the encapsulation material and changing the configuration of the cement and piezoelectric material in the sensor. Two sensors made by the previous and improved methods were embedded in two prisms respectively and the prisms were compressed on Material Test System. Through the comparison of the measurement errors of the two sensors, the improved method was evaluated. The test results show that the improved encapsulation method is effective and feasible.