In this paper,we have presented a simple approach for experimental and application study on LabVIEW based temperature transmitter with NI myRIO device in the laboratory.In this work,to study the small range of tempera...In this paper,we have presented a simple approach for experimental and application study on LabVIEW based temperature transmitter with NI myRIO device in the laboratory.In this work,to study the small range of temperature(40-100℃)although different temperature sensors can be used still,we have used here a K-type thermocouple as the measuring temperature sensor.The analog output voltage of thermocouple is amplified by instrumentation amplifier and the amplified signal is fed to the analog input of NI myRIO device which converts the analog input voltage signal as per the algorithm developed with virtual instrumentation based programming and provides the corresponding 4-20 mA output current signal in the analog output terminal of the device.Results show that input-output i.e.temperature-current relationship is linear.This low cost developed transmitter is very simple and it can be recommended for academic,scientific and industrial development of data acquisition systems,control and analysis of instruments.展开更多
For impulse radio ultra-wideband (IR-UWB) ranging systems,effects of the settings of transmitter-related parameters, which include the pulse shape, the bandwidth and the pulse repetition interval (PRI), on ranging acc...For impulse radio ultra-wideband (IR-UWB) ranging systems,effects of the settings of transmitter-related parameters, which include the pulse shape, the bandwidth and the pulse repetition interval (PRI), on ranging accuracy were studied through theoretical analysis and simulations. Both the match-filtering based coherent TOA estimation algorithm and the energy-detection based non-coherent algorithm were used during simulations. Results show that the pulse shape has the least effect on the ranging accuracy. Increasing the pulse bandwidth can improve the ranging performance, but the performance is hardly improved any more when the bandwidth is increased beyond a certain level. PRI should be set long enough to guarantee the accurate ranging, because when PRI is shorter than the maximum excess delay of the channel, the ranging accuracy will be deteriorated by inter-pulse interference.展开更多
The theory of magnetic circuit design, the constitutive equations of a magneto-theological fluid, and the load properties of belt conveyors were used to design a magneto-rheological soft starter test-bed. The magnetic...The theory of magnetic circuit design, the constitutive equations of a magneto-theological fluid, and the load properties of belt conveyors were used to design a magneto-rheological soft starter test-bed. The magnetic field distribution in the working gap was analyzed and the current-speed relationship was investigated. A mathematical model for the time response was deduced. The results show that a linear relationship between current and magnetic field is seen when the magnetic materials are not saturated and the magnetic field is uniform in the working section. The rotation speed of the driven shaft changes linearly with increasing time. The response is rapid and can be as short as milliseconds. This meets the starting requirements of belt conveyors.展开更多
A heat transfer model for three-fluid separated heat pipe exchanger was analyzed,and the temperature transfer matrix for general three-fluid separated heat exchanger working in parallel-flow or counter-flow mode was o...A heat transfer model for three-fluid separated heat pipe exchanger was analyzed,and the temperature transfer matrix for general three-fluid separated heat exchanger working in parallel-flow or counter-flow mode was obtained.It was found that the forms of temperature transfer matrix are similar for heat pipe rows with equal or different heat transfer surface area.Furthermore,by using the temperature transfer matrix of the heat pipe exchanger,the relationship between heat transfer effectiveness θ 1,θ 2 and M,NTU,U,Δt i were derived for the exchanger operating in parallel-flow or counter-flow mode,and a simple special example was adopted to demonstrate the correctness of these relationships.展开更多
文摘In this paper,we have presented a simple approach for experimental and application study on LabVIEW based temperature transmitter with NI myRIO device in the laboratory.In this work,to study the small range of temperature(40-100℃)although different temperature sensors can be used still,we have used here a K-type thermocouple as the measuring temperature sensor.The analog output voltage of thermocouple is amplified by instrumentation amplifier and the amplified signal is fed to the analog input of NI myRIO device which converts the analog input voltage signal as per the algorithm developed with virtual instrumentation based programming and provides the corresponding 4-20 mA output current signal in the analog output terminal of the device.Results show that input-output i.e.temperature-current relationship is linear.This low cost developed transmitter is very simple and it can be recommended for academic,scientific and industrial development of data acquisition systems,control and analysis of instruments.
基金Sponsored by the National Natural Science Foundation of China (Grant No.60432040)the Natural Science Foundation of Guangdong Privince(Grant No.9451805707003235)
文摘For impulse radio ultra-wideband (IR-UWB) ranging systems,effects of the settings of transmitter-related parameters, which include the pulse shape, the bandwidth and the pulse repetition interval (PRI), on ranging accuracy were studied through theoretical analysis and simulations. Both the match-filtering based coherent TOA estimation algorithm and the energy-detection based non-coherent algorithm were used during simulations. Results show that the pulse shape has the least effect on the ranging accuracy. Increasing the pulse bandwidth can improve the ranging performance, but the performance is hardly improved any more when the bandwidth is increased beyond a certain level. PRI should be set long enough to guarantee the accurate ranging, because when PRI is shorter than the maximum excess delay of the channel, the ranging accuracy will be deteriorated by inter-pulse interference.
基金supported by the National Natural Science Foundation of China (Nos. 50975275 and 51075386)
文摘The theory of magnetic circuit design, the constitutive equations of a magneto-theological fluid, and the load properties of belt conveyors were used to design a magneto-rheological soft starter test-bed. The magnetic field distribution in the working gap was analyzed and the current-speed relationship was investigated. A mathematical model for the time response was deduced. The results show that a linear relationship between current and magnetic field is seen when the magnetic materials are not saturated and the magnetic field is uniform in the working section. The rotation speed of the driven shaft changes linearly with increasing time. The response is rapid and can be as short as milliseconds. This meets the starting requirements of belt conveyors.
文摘A heat transfer model for three-fluid separated heat pipe exchanger was analyzed,and the temperature transfer matrix for general three-fluid separated heat exchanger working in parallel-flow or counter-flow mode was obtained.It was found that the forms of temperature transfer matrix are similar for heat pipe rows with equal or different heat transfer surface area.Furthermore,by using the temperature transfer matrix of the heat pipe exchanger,the relationship between heat transfer effectiveness θ 1,θ 2 and M,NTU,U,Δt i were derived for the exchanger operating in parallel-flow or counter-flow mode,and a simple special example was adopted to demonstrate the correctness of these relationships.
