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2001
Volume: 20 Issue 4
20 Article(s)
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Research Article
STUDY ON THE ELECTRIC CURRENT SENSOR OF FIBER BRAGG GRATING FENG
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A new electric current sensor based on a fiber Bragg grating tuned by a magnetostrictive material rod was obtained. The fiber Bragg grating was firmly clung on a magnetostrictive rod that was put into the central part of a solenoid. The rod was elastically lengthened along the direction of the magnetic field, so the BrA new electric current sensor based on a fiber Bragg grating tuned by a magnetostrictive material rod was obtained. The fiber Bragg grating was firmly clung on a magnetostrictive rod that was put into the central part of a solenoid. The rod was elastically lengthened along the direction of the magnetic field, so the Bragg wavelength of the fiber Bragg grating was changed when the uniform magnetic field in the solenoid increased. The relationship between the electric current in the solenoid and the change of wavelength is basically linear. The wavelength range of linear tuning is about 0.9nm, and its tuning sensitivity is about 0.001nm/mA..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2001
- Vol. 20, Issue 4, 241 (2001)
MAGNETO-OPTIC CURRENT SENSORS BASED ON YbBi∶YIG
[in Chinese]
A co doped Bi substituted rare earth iron garnet single crystal YbBi∶YIG was grown from high temperature solution, and was used first time for magneto optic optical fiber current sensors. The crystal has the specific Faraday rotation angle 404deg/cm, magneto optic figure of merit 25.8deg/dB, saturation magnetic field 1A co doped Bi substituted rare earth iron garnet single crystal YbBi∶YIG was grown from high temperature solution, and was used first time for magneto optic optical fiber current sensors. The crystal has the specific Faraday rotation angle 404deg/cm, magneto optic figure of merit 25.8deg/dB, saturation magnetic field 1400Oe, and temperature coefficient 4.2×10 -4 K -1 (at room temperature, λ=1.55μm). It has larger Faraday rotation angle and magneto optic figure of merit and lower temperature sensibility than pure YIG.A laboratory prototype sensor was established using the YbBi∶YIG crystal as Faraday rotator element, and its sensing performance was tested under a 50Hz frequency AC. The tested results show that the sensor system has high accuracy, sensitivity and good linearity..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2001
- Vol. 20, Issue 4, 244 (2001)
FABRICATION AND STUDY ON THE HgCdTe MIS DEVICE OF CdTe+ZnS DOUBLE INSULATOR FILMS
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2001
- Vol. 20, Issue 4, 249 (2001)
ANALYSIS AND CALCULATION OF THE NONLINEAR RESPONSE IN INFRARED FOCAL PLANE ARRAYS
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Various factors contributing to the nonlinearity response in infrared focal plane array (IRFPA) were analyzed. Then based on the dependence of quantum efficiency on the wavelength of incident photon flux, the global nonlinearity in the response of HgCdTe IRFPA was calculated under quasi ideal conditions. In consideratiVarious factors contributing to the nonlinearity response in infrared focal plane array (IRFPA) were analyzed. Then based on the dependence of quantum efficiency on the wavelength of incident photon flux, the global nonlinearity in the response of HgCdTe IRFPA was calculated under quasi ideal conditions. In consideration of nonuniformity correction, the nonlinearity in the calibrated interval was further calculated. At last, a practical case of residual nonuniformity error attribued to the nonuniformity of response nonlinearity was introduced and interpreted..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2001
- Vol. 20, Issue 4, 253 (2001)
ELECTRICALLY ACTIVE DEFECTS IN HgCdTe AND OPTO-ELECTRONIC PROPER-TIES OF FOCAL PLANE ARRAY BY LASER BEAM INDUCED CURRENT
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A high resolution and nondestructive optical characterization technique called laser beam induced current (LBIC) was utilized to detect electrically active defects in HgCdTe wafers. It was also used to study the opto electronic properties in photovoltaic detector elements for focal plane array without the requirement oA high resolution and nondestructive optical characterization technique called laser beam induced current (LBIC) was utilized to detect electrically active defects in HgCdTe wafers. It was also used to study the opto electronic properties in photovoltaic detector elements for focal plane array without the requirement of any electrical contacts to individual detector elements. The LBIC was detected in HgCdTe wafers. The periodic distribution of LBIC was observed in photovoltaic detector with P N junction array. The uniformity for the performance of the diodes in an array can then be assessed by examining qualitatively the LBIC image and by analyzing quantitatively the profile of LBIC signal corresponding to individual diodes.
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2001
- Vol. 20, Issue 4, 259 (2001)
COMPARATIVE STUDIES OF IR RADIATION CHARACTERISTICS OF TYPICAL GROUND BASED ON A UNIFORM MODEL
[in Chinese], [in Chinese], and [in Chinese]
The uniform model of three kinds of typical grounds, i.e. dry bare ground, wet bare ground and ground covered by low vegetation, was constructed based on the heat balance equation of ground surfave. All kinds of factors were under consideration. In calculation, the Monte Carlo simulation was used to analyze the above nThe uniform model of three kinds of typical grounds, i.e. dry bare ground, wet bare ground and ground covered by low vegetation, was constructed based on the heat balance equation of ground surfave. All kinds of factors were under consideration. In calculation, the Monte Carlo simulation was used to analyze the above natural ground's periodical infrared radiance statistics and the influence on the average value and variance (fluctuation) of the infrared radiation temperature caused by the above circumstance factors. The experimental results show that the model can simulate the infrared radiance statistics of the above typical ground fairly well..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2001
- Vol. 20, Issue 4, 263 (2001)
STUDY ON WIDE-SENSE STATIONARY PROPERTIES OF INFRARED CLUTTER BACKGROUND
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In the paper, the mean and auto covariance are first computed and estimated by means of average across the IR cloudy background clutter image sets. On this basis, the 2 error ranges of them are also computed. Then, experiments on the real IR images are run. The experiment results show that the statistics based on IR clIn the paper, the mean and auto covariance are first computed and estimated by means of average across the IR cloudy background clutter image sets. On this basis, the 2 error ranges of them are also computed. Then, experiments on the real IR images are run. The experiment results show that the statistics based on IR cloudy background clutter images is wide sense stationary..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2001
- Vol. 20, Issue 4, 267 (2001)
FAST RECTIFYING AIRBORNE INFRARED IMAGE BASED ON GPS AND INS
[in Chinese], and [in Chinese]
A new method was tested to fast rectify scanning image based on GPS and INS. The positions of some poxels in a scanning line were calculated first, then these pixels were used to rectify the whole scanning line. The gray interpolation and strips mosaic are also discussed. The data of fligth tests processed using this mA new method was tested to fast rectify scanning image based on GPS and INS. The positions of some poxels in a scanning line were calculated first, then these pixels were used to rectify the whole scanning line. The gray interpolation and strips mosaic are also discussed. The data of fligth tests processed using this method shows it is feasible..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2001
- Vol. 20, Issue 4, 271 (2001)
EFFECT OF ATMOSPHERIC AEROSOLS ON REMOTE SENSING OF LAND SURFACE TEMPERATURE AT INFRARED WINDOW CHANNELS
[in Chinese], [in Chinese], and [in Chinese]
The effects of atmospheric aerosols on radiative transfer in infrared window channels were analyzed. For the land surface temperature retrieval at infrared window channels, the effects of the uncertainties in atmospheric aerosol and the effects of the deviations in atmospheric temperature, moisture and aerosol on the rThe effects of atmospheric aerosols on radiative transfer in infrared window channels were analyzed. For the land surface temperature retrieval at infrared window channels, the effects of the uncertainties in atmospheric aerosol and the effects of the deviations in atmospheric temperature, moisture and aerosol on the retrieval accuracy were investigated..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2001
- Vol. 20, Issue 4, 275 (2001)
REAL-TIME DETECTION AND TRACKING OF LIGHT POINT
[in Chinese], [in Chinese], and [in Chinese]
A method of detecting and tracking light points in realtime images was proposed. Detection of light points was based on analyzing of the segmentation results and graylevel change in different directions, which can distinguish light points from reflector points. Tracking of light points is based on adaptive adjustment oA method of detecting and tracking light points in realtime images was proposed. Detection of light points was based on analyzing of the segmentation results and graylevel change in different directions, which can distinguish light points from reflector points. Tracking of light points is based on adaptive adjustment of gate size and gate position. In order to improve computing precision, the Cardinal spline functions are used as the interpolating functions. This method is feasible and the results agree with the relative experiment..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2001
- Vol. 20, Issue 4, 279 (2001)
EXPERIMENTAL STUDY OF APOPTOSIS AND ITS MOLECULAR MECHANISMS OF NASOPHARYNGEAL CARCINOMA CELL INDUCED BY MILLIMETER WAVE IRRADIATION
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The effect of millimeter wave radiation on the nasopharyngeal carcinoma cell line CNE 1 cell proliferation and apoptosis and the expression of related genes was studied by using cell count, light microscopy and the flow cytometry (FCM). By millimeter wave radiation with 1 mW/cm 2 power density at frequency 42.2GHz and The effect of millimeter wave radiation on the nasopharyngeal carcinoma cell line CNE 1 cell proliferation and apoptosis and the expression of related genes was studied by using cell count, light microscopy and the flow cytometry (FCM). By millimeter wave radiation with 1 mW/cm 2 power density at frequency 42.2GHz and wave length 7.1mm on CNE 1 cells for a duration of 30min/day for 4 days, cell proliferation and cloning formation were inhibited markedly, and cell apoptosis was induced. FCM also revealed that the inhibiting effect of CNE 1 proliferation by millimeter wave was probably associated with the up regulation of P21 and the down regulation of Cyclin D 1. The molecular mechanism of apoptosis inducing may be p53 independent and c Myc dependent. The up regulation of c Myc and Fas and down regulation of Bcl 2 may play an important role in the process of apoptosis..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2001
- Vol. 20, Issue 4, 283 (2001)
Effects of Na+ ions on breathing vibrational modes of poly (dT).poly(dA).poly(dT)
[in Chinese], and [in Chinese]
A lattice dynamics model for poly(dT)·poly(dA)·poly(dT), which is one of the best important triplex DNA was presented based on its screw symmetry. In this model, the presence of Na + ions was included explicitly. The breathing modes of poly(dT)·poly(dA)·poly(dT) were calculated. By comparing the isoA lattice dynamics model for poly(dT)·poly(dA)·poly(dT), which is one of the best important triplex DNA was presented based on its screw symmetry. In this model, the presence of Na + ions was included explicitly. The breathing modes of poly(dT)·poly(dA)·poly(dT) were calculated. By comparing the isolated triplex vibrational modes, it was found that the addition of Na + ions could extinguish very strong breathing modes of Hoogensteen hydrogen bond located in 18.4cm 1?36.4cm 1 and 43.8cm 1. The breathing modes of Watson Crick hydrogen bond were not changed obviously. These results indicate that Na + ions can increase the stability of poly(dT)·poly(dA)·poly(dT) and reasonably explain the melting experiment of poly(dT)·poly(dA)·poly(dT)..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2001
- Vol. 20, Issue 4, 287 (2001)
PREPARATION AND CHARACTERIZATION OF THERMALLY SENSITIVE VANADIUM OXIDE FILMS
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A new method of preparation of vanadium oxide films was reported.A thin VO x(x<2.5) film with good thermal sensitivity was prepared by ion beam sputtering of a V 2O 5 powder target and with a subsequent reduction annealing in mixing gas of N 2+H 2. The VO x(x<2.5) film has a negative temperature coefficient of reA new method of preparation of vanadium oxide films was reported.A thin VO x(x<2.5) film with good thermal sensitivity was prepared by ion beam sputtering of a V 2O 5 powder target and with a subsequent reduction annealing in mixing gas of N 2+H 2. The VO x(x<2.5) film has a negative temperature coefficient of resistance (TCR) of (-1~-4)%K -1 ,and an activation energy of 0.078eV~0.110eV. The relatively high TCR as well as low formation temperature shows that the film prepared by the new method is promising for application as thermal sensor material in an uncooled IR microbolometer..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2001
- Vol. 20, Issue 4, 291 (2001)
CODING OF IMAGE OBJECTS BASED ON WAVELET TRANSFORM USING LIFTING SCHEME
[in Chinese], and [in Chinese]
Wavelet lifting scheme was applied to the transform coding of arbitrarily shaped image objects. There are two approaches: one needs the extrapolation of the image object and the other is a shape adopted algorithm by modifying the lifting scheme. The experiment result shows that the image compression performance of the Wavelet lifting scheme was applied to the transform coding of arbitrarily shaped image objects. There are two approaches: one needs the extrapolation of the image object and the other is a shape adopted algorithm by modifying the lifting scheme. The experiment result shows that the image compression performance of the two approaches is better than Katata's approach which uses the classical wavelet transform..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2001
- Vol. 20, Issue 4, 296 (2001)
A NOVEL FINLINE SPDT SWITCH
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The design method, manufacture and testing results of new kind of T junction finline single pole double throw (SPDT) switch, which has only a controlling port with positive or negative pulses, was given. In order to increase the isolation and reduce the insert loss of the switch, some improving measures were taken in tThe design method, manufacture and testing results of new kind of T junction finline single pole double throw (SPDT) switch, which has only a controlling port with positive or negative pulses, was given. In order to increase the isolation and reduce the insert loss of the switch, some improving measures were taken in the circuit. The test results show that the insert loss≤1.5dB and the isolation≥30dB in Ka bands and the insert loss≤2dB and the isolation≥25dB in W bands..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2001
- Vol. 20, Issue 4, 301 (2001)
MILLIMETER WAVE MIXER WITH IMAGE RECOVERY USING DIELECTRIC RESONATORS
[in Chinese], [in Chinese], and [in Chinese]
The millimeter wave mixer with image recovery was presented, which used dielectric resonators at Ka band as the band rejection filter. The real circuit was also presented based on the theoretical analysis. The results show that the signal conversion loss is reduced by about 1.1dB, and the image to signal conversion losThe millimeter wave mixer with image recovery was presented, which used dielectric resonators at Ka band as the band rejection filter. The real circuit was also presented based on the theoretical analysis. The results show that the signal conversion loss is reduced by about 1.1dB, and the image to signal conversion loss ratio is larger than 26dB by using the millimeter wave mixer image recovery..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2001
- Vol. 20, Issue 4, 304 (2001)
A SPECKLE SUPPRESSION METHOD BASED ON NONLINEAR THRESHOLD WAVELET PACKET IN ULTRASOUND IMAGES
[in Chinese], and [in Chinese]
A novel method based on nonlinear threshold wavelet packet was explored in order to suppress the speckles in B scan 3 D ultrasound imaging. Firstly, an original image was separated into two parts by adaptive pre filtering. These two parts were then transformed into a multiscale wavelet packet (WP) domain and the WP coeA novel method based on nonlinear threshold wavelet packet was explored in order to suppress the speckles in B scan 3 D ultrasound imaging. Firstly, an original image was separated into two parts by adaptive pre filtering. These two parts were then transformed into a multiscale wavelet packet (WP) domain and the WP coefficients were processed by a soft thresholding filter method. The processed coefficients for each part were then transformed back into the space domain. Finally, the de noised image was obtained as the sum of the two processed parts. Performance of this new method has been tested by a computer simulated image. Ultrasound images set of a plastic bowl in a water tank has been utilized for 3 D ultrasound reconstruction. It was found that this technique reduces the speckle noise effectively, and preserves the resolvable details..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2001
- Vol. 20, Issue 4, 307 (2001)
PASSIVE RANGING METHOD FOR IRST SYSTEMS
[in Chinese]
A passive ranging method for IRST systems aimed at uniform velocity point targets was presented. Target model has been built firstly, then the range equations set based on this model were developed. The peculiarity of this mothed is that the velocities, ranges and radiant intensities can be worked out, without targets A passive ranging method for IRST systems aimed at uniform velocity point targets was presented. Target model has been built firstly, then the range equations set based on this model were developed. The peculiarity of this mothed is that the velocities, ranges and radiant intensities can be worked out, without targets database and supposing the parameters of targets just like velocities, only with the angles and radiations of the targets measurd by IRST systems. The computer simulation verifies the validity of the method..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2001
- Vol. 20, Issue 4, 311 (2001)
INVESTIGATION OF LONG-WAVELENGTH OPTICAL-PHONONS IN GaxIn1-xAsySb1-yQUA TERNARY MIXED CRYSTAL BY RAMAN SCATTERING SPECTROSCOPIES AND FIR REFLECTION SPECTRA
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The long wavelength optical phonons in Ga x In 1- x As y Sb 1- y MBE epitaxial layers were investigated by Raman scattering spectroscopies and FIR reflection spectra. The four mode behavior and modes below 180cm -1 related with the interaction between the third nearest atoms in Ga x In 1- x As y Sb 1- y quaternary mixeThe long wavelength optical phonons in Ga x In 1- x As y Sb 1- y MBE epitaxial layers were investigated by Raman scattering spectroscopies and FIR reflection spectra. The four mode behavior and modes below 180cm -1 related with the interaction between the third nearest atoms in Ga x In 1- x As y Sb 1- y quaternary mixed crystals were observed from the Raman data, and the related phenomenon possibly arising from the multi phonon absorption process was observed from the FIR and Raman data..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2001
- Vol. 20, Issue 4, 315 (2001)
PHOTOCURRENT AND ELECTRON INTERFERENCE OF GaAs/AlGaAs MULTIQUANTUM WELL STRUCTURE
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Photocurrent spectrum for GaAs/AlGaAs multiquantum well structure was measured at 77K. A strong photocurrent peak at ν =1589cm -1 ,i.e. λ =6.29μm,in the photocurrent spectrum was observed. It was believed that the strong photocurrent peak is relevant to the interference of electrons above the barrier of multiquantum wePhotocurrent spectrum for GaAs/AlGaAs multiquantum well structure was measured at 77K. A strong photocurrent peak at ν =1589cm -1 ,i.e. λ =6.29μm,in the photocurrent spectrum was observed. It was believed that the strong photocurrent peak is relevant to the interference of electrons above the barrier of multiquantum well structure. The calculated position of peak of photocurrent on the basis of theory of electron interference is in very good agreement with the experimental results..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2001
- Vol. 20, Issue 4, 318 (2001)
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