A fitting process is used to measure the cavity loss and the quasi Fermi level separation for Fabry Pérot semiconductor lasers.From the amplified spontaneous emission (ASE) spectrum,the gain spectrum and sing...A fitting process is used to measure the cavity loss and the quasi Fermi level separation for Fabry Pérot semiconductor lasers.From the amplified spontaneous emission (ASE) spectrum,the gain spectrum and single pass ASE obtained by the Cassidy method are applied in the fitting process.For a 1550nm quantum well InGaAsP ridge waveguide laser,the cavity loss of about ～24cm -1 is obtained.展开更多
A novel system configuration of fiber optic sensor based on optical abso rption is proposed. Several compensation measures are discussed. A simulated exp eriment is designed and the output curve of system is given. Th...A novel system configuration of fiber optic sensor based on optical abso rption is proposed. Several compensation measures are discussed. A simulated exp eriment is designed and the output curve of system is given. The experiment al result shows that these compensation measures are effective on dynamic distu rbances which are caused by background light and optical fiber bend. In addition , the drifts in the light source intensity, fiber losses, and photodetector effi ciency are also compensated.展开更多
Abstract: A micro - power consumption non - contact temperature measuring instrument for big rotor is introduced. As it solves very well the signal coupling under high speed rotation and power supply problem for probe...Abstract: A micro - power consumption non - contact temperature measuring instrument for big rotor is introduced. As it solves very well the signal coupling under high speed rotation and power supply problem for probe, the instrument can realize persistent on - line temperature measurement for big rotor drived by the ordinary light transmitted by optical fiber under the room light.展开更多
Abstract: The force sensing resistor (FSR) and its con’struction and characteristic are described. By using the optimal electronic interface, the end result which is a direct proportionality between force and voltage...Abstract: The force sensing resistor (FSR) and its con’struction and characteristic are described. By using the optimal electronic interface, the end result which is a direct proportionality between force and voltage is obtained. The circuits of application for force and position measurements in the robotic control are given. The experiment that FSRs are placed on the fingers of BH - 1 dexterous hand as tactile sensors to measure the contacting forces shows FSR’s force sensitivity is optimized for use in the control of robot contacting with environment.展开更多
Using a Taylor series expansion for the Fermi-Dirac occupation function,an accurate analytical model is developed for calculating the trapped-charge density in a-Si: H considering deep and tail states simultaneously w...Using a Taylor series expansion for the Fermi-Dirac occupation function,an accurate analytical model is developed for calculating the trapped-charge density in a-Si: H considering deep and tail states simultaneously without simplification.This is followed by the investigation of the relative errors of the localized trapped charge density in a-Si:H at all temperatures as a function of the quasi-Fermi level in the band gap calculated from three published analytical models and our above model. The results suggest that the relative errors of all these models increase notably as Efn is very closed to Ec(e.g.,-0.01 eV< Efn-Ec).It is also noticed that the relative errors of all above models become larger normally the greater is the value of temperature.A detailed analysis indicates that each model has its own applicability with various temperatures and various positions of the Fermi level.展开更多
The method for measuring the strain of an object using an optical fiber and a frequency modulation(FM) coupled cavity semiconductor laser is proposed.This method uses the coherent FM heterodyne principle of the Michel...The method for measuring the strain of an object using an optical fiber and a frequency modulation(FM) coupled cavity semiconductor laser is proposed.This method uses the coherent FM heterodyne principle of the Michelson interferometer and can avoid the π/2 nonreciprocal phase bias and phase shifting problem existing in general fiber optic interferential sensors, the maximum detection range is limited by the coherent length of the semiconductor laser and its relative factor.展开更多
A precise zoom magnification is important for semiconductor industry and biomedical research. A novel measurement method is demonstrated for optical zoom magnification measurement in this paper. The magnification is o...A precise zoom magnification is important for semiconductor industry and biomedical research. A novel measurement method is demonstrated for optical zoom magnification measurement in this paper. The magnification is obtained by pattern correction between barcode image formed by optical zoom and reference image generated by an ideal optical model. Measurement accuracy which is better than 0.06% has been achieved for optical zoom magnification. Compared with traditional concept, the measurement results are only dependent on two line edges. The barcode correlation method can achieve higher accuracy and better robustness by using the information over the whole field of view.展开更多
micro-electro-mechanical system （MEMS） device has the advantages of both electronic system and mechanical system. With the development of MEMS devices for satellite, it is possible to establish much lighter and smal...micro-electro-mechanical system （MEMS） device has the advantages of both electronic system and mechanical system. With the development of MEMS devices for satellite, it is possible to establish much lighter and smaller nanosatellites with higher performance and longer lifecyele. The power consumption of MEMS devices is usually much lower than that of traditional devices, which will greatly reduce the consumption of power. For its small size and simple architecture, MEMS devices can be easily integrated together and achieve redundancy. Launched on April 18, 2004, NS - 1 is a nanosatellite for science exploration and MEMS devices test. A mass of science data and images were acquired during its running. NS - 1 weights less than 25 kg. It consists of several MEMS devices, including one miniature inertial measurement unit（MIMU） , three micro complementary metal oxide semiconductor （CMOS）cameras, one sun sensor, three momentum wheels, and one micro magnetic sensor. By applying micro components based on MEMS technology, NS - 1 has made success in the experiments of integrative design, manufacture, and MEMS devices integration. In this paper, some MEMS devices for nanosatellite and picosatellite are introduced, which have been tested on NS -1 nanosatellite or on the ground.展开更多
The purpose of the present study is to evaluate the uncertainties of in vivo dosimetry measured with diode detectors for conformal radiation therapy techniques in order to define appropriate tolerance levels for pelvi...The purpose of the present study is to evaluate the uncertainties of in vivo dosimetry measured with diode detectors for conformal radiation therapy techniques in order to define appropriate tolerance levels for pelvis and breast treatment in MEIH （Middle East Institute of Health）. The present work is carried out on 30-472 and 30-473 diode detectors irradiated by 4 and 15MV photon beams of a medical linear accelerator Synergy from ELEKTA. Dose computation is performed with Pinnacle 7.4 k treatment planning system. First, an estimation of the uncertainties in a simple geometric case, using a water-equivalent solid phantom is done. Secondly, each treatment parameter such as field size, beam angle, beam modifiers and source-skin distance is evaluated in order to simulate the conformal radiation treatments used in the present institution for the main anatomical sites. Interpretation of entrance dose in-vivo measurements requires the determination of appropriate tolerance levels. Indeed, the authors found that the 5% action level proposed in the literature underestimates the uncertainties in the treatment process. A method for the evaluation of tolerance/action levels related to the different anatomical sites is developed. By the end of the present study the authors have developed an integrated monitoring system that offers accurate information about the dose received by patients.展开更多
Semiconductor quantum dots have attracted wide interest for the potential realization of quantum computation. To realize efficient quantum computation, fast manipulation and the corresponding readout are necessary. In...Semiconductor quantum dots have attracted wide interest for the potential realization of quantum computation. To realize efficient quantum computation, fast manipulation and the corresponding readout are necessary. In the past few decades, considerable progress of quantum manipulation has been achieved experimentally. To meet the requirements of high-speed readout, radio-frequency （RF） measurement has been developed in recent years, such as RF-QPC （radio-frequency quantum point contact） and RF-DGS （radio-frequency dispersive gate sensor）. Here we specifically demonstrate the principle of the radio-frequency reflectometry, then review the development and applications of RF measurement, which provides a feasible way to achieve high-bandwidth readout in quantum coherent control and also enriches the methods to study these artificial mesoscopic quantum systems. Finally, we prospect the future usage of radio-frequency reflectometry in scaling-up of the quantum computing models.展开更多
We present in this paper a new method,based on measurements of conventional direct current-voltage(I-V) characteristics and transient voltage-time(V-t) characteristics during the discharge process,for determining capa...We present in this paper a new method,based on measurements of conventional direct current-voltage(I-V) characteristics and transient voltage-time(V-t) characteristics during the discharge process,for determining capacitance-voltage(C-V) characteris-tics of organic semiconductor devices.Derivatives of I-V and V-t,dI/dV and dV/dt,are related with C by a simple formula C=-V(dI/dV)/(dV/dt)The validity of the method is confirmed by experimental data measured from a set of single-organic-layer devices with different layer thicknesses.展开更多
文摘A fitting process is used to measure the cavity loss and the quasi Fermi level separation for Fabry Pérot semiconductor lasers.From the amplified spontaneous emission (ASE) spectrum,the gain spectrum and single pass ASE obtained by the Cassidy method are applied in the fitting process.For a 1550nm quantum well InGaAsP ridge waveguide laser,the cavity loss of about ～24cm -1 is obtained.
文摘A novel system configuration of fiber optic sensor based on optical abso rption is proposed. Several compensation measures are discussed. A simulated exp eriment is designed and the output curve of system is given. The experiment al result shows that these compensation measures are effective on dynamic distu rbances which are caused by background light and optical fiber bend. In addition , the drifts in the light source intensity, fiber losses, and photodetector effi ciency are also compensated.
文摘Abstract: A micro - power consumption non - contact temperature measuring instrument for big rotor is introduced. As it solves very well the signal coupling under high speed rotation and power supply problem for probe, the instrument can realize persistent on - line temperature measurement for big rotor drived by the ordinary light transmitted by optical fiber under the room light.
文摘Abstract: The force sensing resistor (FSR) and its con’struction and characteristic are described. By using the optimal electronic interface, the end result which is a direct proportionality between force and voltage is obtained. The circuits of application for force and position measurements in the robotic control are given. The experiment that FSRs are placed on the fingers of BH - 1 dexterous hand as tactile sensors to measure the contacting forces shows FSR’s force sensitivity is optimized for use in the control of robot contacting with environment.
文摘Using a Taylor series expansion for the Fermi-Dirac occupation function,an accurate analytical model is developed for calculating the trapped-charge density in a-Si: H considering deep and tail states simultaneously without simplification.This is followed by the investigation of the relative errors of the localized trapped charge density in a-Si:H at all temperatures as a function of the quasi-Fermi level in the band gap calculated from three published analytical models and our above model. The results suggest that the relative errors of all these models increase notably as Efn is very closed to Ec(e.g.,-0.01 eV< Efn-Ec).It is also noticed that the relative errors of all above models become larger normally the greater is the value of temperature.A detailed analysis indicates that each model has its own applicability with various temperatures and various positions of the Fermi level.
文摘The method for measuring the strain of an object using an optical fiber and a frequency modulation(FM) coupled cavity semiconductor laser is proposed.This method uses the coherent FM heterodyne principle of the Michelson interferometer and can avoid the π/2 nonreciprocal phase bias and phase shifting problem existing in general fiber optic interferential sensors, the maximum detection range is limited by the coherent length of the semiconductor laser and its relative factor.
文摘A precise zoom magnification is important for semiconductor industry and biomedical research. A novel measurement method is demonstrated for optical zoom magnification measurement in this paper. The magnification is obtained by pattern correction between barcode image formed by optical zoom and reference image generated by an ideal optical model. Measurement accuracy which is better than 0.06% has been achieved for optical zoom magnification. Compared with traditional concept, the measurement results are only dependent on two line edges. The barcode correlation method can achieve higher accuracy and better robustness by using the information over the whole field of view.
文摘micro-electro-mechanical system （MEMS） device has the advantages of both electronic system and mechanical system. With the development of MEMS devices for satellite, it is possible to establish much lighter and smaller nanosatellites with higher performance and longer lifecyele. The power consumption of MEMS devices is usually much lower than that of traditional devices, which will greatly reduce the consumption of power. For its small size and simple architecture, MEMS devices can be easily integrated together and achieve redundancy. Launched on April 18, 2004, NS - 1 is a nanosatellite for science exploration and MEMS devices test. A mass of science data and images were acquired during its running. NS - 1 weights less than 25 kg. It consists of several MEMS devices, including one miniature inertial measurement unit（MIMU） , three micro complementary metal oxide semiconductor （CMOS）cameras, one sun sensor, three momentum wheels, and one micro magnetic sensor. By applying micro components based on MEMS technology, NS - 1 has made success in the experiments of integrative design, manufacture, and MEMS devices integration. In this paper, some MEMS devices for nanosatellite and picosatellite are introduced, which have been tested on NS -1 nanosatellite or on the ground.
文摘The purpose of the present study is to evaluate the uncertainties of in vivo dosimetry measured with diode detectors for conformal radiation therapy techniques in order to define appropriate tolerance levels for pelvis and breast treatment in MEIH （Middle East Institute of Health）. The present work is carried out on 30-472 and 30-473 diode detectors irradiated by 4 and 15MV photon beams of a medical linear accelerator Synergy from ELEKTA. Dose computation is performed with Pinnacle 7.4 k treatment planning system. First, an estimation of the uncertainties in a simple geometric case, using a water-equivalent solid phantom is done. Secondly, each treatment parameter such as field size, beam angle, beam modifiers and source-skin distance is evaluated in order to simulate the conformal radiation treatments used in the present institution for the main anatomical sites. Interpretation of entrance dose in-vivo measurements requires the determination of appropriate tolerance levels. Indeed, the authors found that the 5% action level proposed in the literature underestimates the uncertainties in the treatment process. A method for the evaluation of tolerance/action levels related to the different anatomical sites is developed. By the end of the present study the authors have developed an integrated monitoring system that offers accurate information about the dose received by patients.
基金supported by the National Key Research&Development Program(Grant No.2016YFA0301700)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB01030000)+1 种基金the National Natural Science Foundation of China(Grant Nos.11674300,11575172,61674132,and 91421303)the Fundamental Research Fund for the Central Universities
文摘Semiconductor quantum dots have attracted wide interest for the potential realization of quantum computation. To realize efficient quantum computation, fast manipulation and the corresponding readout are necessary. In the past few decades, considerable progress of quantum manipulation has been achieved experimentally. To meet the requirements of high-speed readout, radio-frequency （RF） measurement has been developed in recent years, such as RF-QPC （radio-frequency quantum point contact） and RF-DGS （radio-frequency dispersive gate sensor）. Here we specifically demonstrate the principle of the radio-frequency reflectometry, then review the development and applications of RF measurement, which provides a feasible way to achieve high-bandwidth readout in quantum coherent control and also enriches the methods to study these artificial mesoscopic quantum systems. Finally, we prospect the future usage of radio-frequency reflectometry in scaling-up of the quantum computing models.
基金supported by the Shanghai Committee of Science and Technology, China (Grant No. 08Jc1402300)
文摘We present in this paper a new method,based on measurements of conventional direct current-voltage(I-V) characteristics and transient voltage-time(V-t) characteristics during the discharge process,for determining capacitance-voltage(C-V) characteris-tics of organic semiconductor devices.Derivatives of I-V and V-t,dI/dV and dV/dt,are related with C by a simple formula C=-V(dI/dV)/(dV/dt)The validity of the method is confirmed by experimental data measured from a set of single-organic-layer devices with different layer thicknesses.
