Journals >Journal of Infrared and Millimeter Waves
Contents
2002
Volume: 21 Issue 4
18 Article(s)
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Research Article
INVESTIGATION OF OPTICAL PHONONS FOR PbZrxTi1-xO3 WITH THE VIRTUAL CRYSTAL APPROXIMATION
[in Chinese], [in Chinese], and [in Chinese]
The phonon vibration frequencies of PbZr x Ti 1- x O 3( x =0 25～0 40)at Г point in the Brillioun zone were calculated by using the rigid ion model in the frame of the virtual crystal approximation. The results show that the transverse optical phonon frequencies of PbZr xTi 1-x O 3 shift toward the lower frequency with The phonon vibration frequencies of PbZr x Ti 1- x O 3( x =0 25～0 40)at Г point in the Brillioun zone were calculated by using the rigid ion model in the frame of the virtual crystal approximation. The results show that the transverse optical phonon frequencies of PbZr xTi 1-x O 3 shift toward the lower frequency with increasing composition x of Zr, which is in accordance with the data of Raman experiments..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2002
- Vol. 21, Issue 4, 241 (2002)
ESTIMATION OF NONLINEAR RESIDUAL FREQUENCY ERRORS IN FREQUENCY MODULATION FOR MM-WAVE LFMCW RADAR
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
An estimation method of the nonlinear residual frequency errors for frequency modulation in LFMCW radar was proposed based on zero crossing detection and periodogram,and analysis of the zero crossing detection errors in phase modulation sinusoid signal was given in details.Simulations demonstrate that this method proviAn estimation method of the nonlinear residual frequency errors for frequency modulation in LFMCW radar was proposed based on zero crossing detection and periodogram,and analysis of the zero crossing detection errors in phase modulation sinusoid signal was given in details.Simulations demonstrate that this method provides an accurate estimation of nonlinear residual frequency errors with high computation efficiency.An experimental result was also given..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2002
- Vol. 21, Issue 4, 245 (2002)
LINEAR THEORY OF THE BEAM-WAVE INTERACTION IN THE HIGH POWER RING-PLANE TWT AT THE MILLIMETER WAVE BAND
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In consideration of the thickness and the relativistic effect of the hollow electron beam, the hot dispersion relation including the electron beam space charge effect for the ring plane traveling wave tube was derived by making use of the Ritz Galerkin method and combining with the field matching method. The numerical In consideration of the thickness and the relativistic effect of the hollow electron beam, the hot dispersion relation including the electron beam space charge effect for the ring plane traveling wave tube was derived by making use of the Ritz Galerkin method and combining with the field matching method. The numerical results given were in terms of the small signal gain curve. Finally, the influences of the radius and current of the electron beam, the acceleration voltage and the geometrical dimensions of the slow wave structure on the small signal gain were discussed. The results presented in this paper provide theoretical basis on designing the millimeter wave ring plane traveling wave tube..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2002
- Vol. 21, Issue 4, 251 (2002)
SPECTROSCOPIC STUDIES ON THE α AND β FORMS OF COPPER PHTHALOCYANINE NANOPARTICLES
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The corresponding Copper Phthalocyanine(CuPc)nanoparticles have been fabricated in aqueous solution by laser ablation with the α and β crystalline forms of CuPc original powders respectively.X ray diffraction patterns,UV Vis absorption spectroscopy and Fourier transform infrared spectroscopy have been used to analyze tThe corresponding Copper Phthalocyanine(CuPc)nanoparticles have been fabricated in aqueous solution by laser ablation with the α and β crystalline forms of CuPc original powders respectively.X ray diffraction patterns,UV Vis absorption spectroscopy and Fourier transform infrared spectroscopy have been used to analyze the crystalline structures of obtained CuPc nanoparticles.The results have shown that the crystalline structures of the α and β forms of CuPc have no change before and after laser ablation.It indicates that both α and β forms of CuPc are stable during laser ablation and laser ablation is a simple and efficiency method to fabricate the nanoparticles of above two forms of CuPc..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2002
- Vol. 21, Issue 4, 257 (2002)
IMPLEMENTATION OF THE IR IMAGE TRACK SYSTEM WITH COTS MULTIPROCESSORS
[in Chinese], [in Chinese], and [in Chinese]
This paper describes a real time IR image track system implemented with COTS multiprocessors. The implementation of a real time IR image processing algorithm onto the processors is discussed. The architecture of the hardware and software of the system was described, too. The use of programmable image processing of the This paper describes a real time IR image track system implemented with COTS multiprocessors. The implementation of a real time IR image processing algorithm onto the processors is discussed. The architecture of the hardware and software of the system was described, too. The use of programmable image processing of the system provides increased adaptability to higher performance robust algorithms and flexibility for future modification. It is proved by the experiment that the system has good ability of tracking multiple targets.
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2002
- Vol. 21, Issue 4, 261 (2002)
APPLICATION OF THE NEURAL NETWORK TO MMW STEPPED-FREQUENCY RADAR SIGNAL PROCESSING
[in Chinese], [in Chinese], and [in Chinese]
Based on the energy function optimization theory of the artificial neural network,a theoretical frame of neural network algorithm was presented to produce 1 D range profile of MMW stepped frequency radar and some simulation experiments were done.Because of the parallel computation of the neural network,the method develBased on the energy function optimization theory of the artificial neural network,a theoretical frame of neural network algorithm was presented to produce 1 D range profile of MMW stepped frequency radar and some simulation experiments were done.Because of the parallel computation of the neural network,the method developed by the authors has the advantage of rapidness..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2002
- Vol. 21, Issue 4, 266 (2002)
TARGET CLASSIFICATION AND SOIL WATER CONTENT REGRESSION USING LAND SURFACE TEMPERATURE(LST)AND VEGETATION INDEX(VI)
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Land surface temperature(LST) and NDVI were used for classification and soil water content(SWC) regression. Firstly, the 6 kinds of targets, dense wheat, sparse wheat, naked soil, water in ponds, silt and aquatic plants, were well classified using LST and NDVI channels. Secondly, the triangle shaped scatter plot was buLand surface temperature(LST) and NDVI were used for classification and soil water content(SWC) regression. Firstly, the 6 kinds of targets, dense wheat, sparse wheat, naked soil, water in ponds, silt and aquatic plants, were well classified using LST and NDVI channels. Secondly, the triangle shaped scatter plot was built and analyzed using LST and NDVI channels. Compared with the scatter plot built by red and near infrared bands, the spectral distances between different clatssifications are larger, and the samples in the same classification are more convergent. Finally, a VIT model was presented to extract SWC using LST and NDVI channel, which predicts the moisture well. The mapping of soil's moisture in the wheat area was calculated and illustrated for scientific irrigation and precise agriculture..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2002
- Vol. 21, Issue 4, 269 (2002)
HEAD-SHOULDER OBJECT SEGMENTATION BASED ON BI-MOTION MODEL
[in Chinese], and [in Chinese]
A new method of segmenting head and shoulder object was presented by using the bi motion model, which is better in describing such objects' motion than single motion model. An algorithm was developed to estimate the model parameter and implemented in an semi automatic segmentation system. The simulated result reveaA new method of segmenting head and shoulder object was presented by using the bi motion model, which is better in describing such objects' motion than single motion model. An algorithm was developed to estimate the model parameter and implemented in an semi automatic segmentation system. The simulated result reveals that the segmentation system using the authors' bi motion model can segment head and shoulder object more accurately..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2002
- Vol. 21, Issue 4, 275 (2002)
RESEARCH ON 1-D AND 2-D PBG STRUCTURE BASED ON FDTD METHOD
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The 1 D and 2 D photonic band gap(PBG) structure used in microstrip was studied by using FDTD technique. Several PBG circuits were fabricated for comparing the calculational results with experimental ones. The effects on the stopband formed by PBG structure were analyzed detailedly, which brought form the length and nuThe 1 D and 2 D photonic band gap(PBG) structure used in microstrip was studied by using FDTD technique. Several PBG circuits were fabricated for comparing the calculational results with experimental ones. The effects on the stopband formed by PBG structure were analyzed detailedly, which brought form the length and numbers of period of PBG structure, unit's size and shape, etc., and conclusions were given..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2002
- Vol. 21, Issue 4, 281 (2002)
TEMPERATURE DEPENDENCE OF OPTICAL GAIN IN InGaAs QUANTUM DOTS LASER
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The temperature dependence of gain in InGaAs multi stacked quantum dots (QDs) laser was investigated and compared with InGaAs single quantum well(SQW) laser. It was found that quantum dost laser showed a much better stability of gain on temperature. The gain in InGaAs QDs increases with temperature in the region from 1The temperature dependence of gain in InGaAs multi stacked quantum dots (QDs) laser was investigated and compared with InGaAs single quantum well(SQW) laser. It was found that quantum dost laser showed a much better stability of gain on temperature. The gain in InGaAs QDs increases with temperature in the region from 140K to 200K. Beyond 200K the gain decreases with increasing temperature. The mechanism for the above gain characteristics was analyzed. The gain peak wavelength moves to longer wavelength range with increasing temperature and exhitits a better temperature stability compared with quantum well laser..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2002
- Vol. 21, Issue 4, 285 (2002)
MODE SELECTION OF A MODERATE POWER GYROTRON OPERATING AT THE ISM FREQUENCY
[in Chinese], [in Chinese], and [in Chinese]
Mode selection of a moderate power gyrotron operating at the ISM frequency and the second harmonic is discussed in detail. By analysis and calculation for electron beam wave coupling, mode competition, voltage depression and limiting current, and ohmic losses, considering the compactness of the configuration, the resulMode selection of a moderate power gyrotron operating at the ISM frequency and the second harmonic is discussed in detail. By analysis and calculation for electron beam wave coupling, mode competition, voltage depression and limiting current, and ohmic losses, considering the compactness of the configuration, the result obtained is that TE 31 mode is probably a best choice for the technology gyrotron operating at the ISM frequency..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2002
- Vol. 21, Issue 4, 289 (2002)
NEW IMPROVEMENT OF UNCERTAINTY RELATION SUITED TO OVERFITTING OF BP NEURAL NETWORK
[in Chinese], and [in Chinese]
Based on the analogue of general uncertainty relation in information transmitting processes, by the introduction of multi correlative coefficient R to manifest the complexity of the function and the hidden unit h to manifest the complexity of the network structure, a general uncertainty relation between the learning abBased on the analogue of general uncertainty relation in information transmitting processes, by the introduction of multi correlative coefficient R to manifest the complexity of the function and the hidden unit h to manifest the complexity of the network structure, a general uncertainty relation between the learning ability and the generalization ability suited to overfitting of BP neural network was revealed in the modeling of BP neural network. Tests of numerical simulation for 12 kinds of complicated function were carried out to determine the value distribution (1×10 -5 ～5×10 -4 ) of overfitting parameter in the uncertainty relation. Based on the uncertainty relation, the judgement of overfitting in the training process of gived sample sets using BP network was given..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2002
- Vol. 21, Issue 4, 293 (2002)
THE DEFECTS OF CURRENT CLINICAL MICROWAVE RADIATOR AND RESEARCH DIRECTION
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The results, albumen thermo solidification experiment and leaking dynamometer are used to investigate the radiant power density field radiated from a microwave antenna, show that the microwave field radiated from the monopole antennas, which are used usually in clinical treatments now, is not uniform. The radiation intThe results, albumen thermo solidification experiment and leaking dynamometer are used to investigate the radiant power density field radiated from a microwave antenna, show that the microwave field radiated from the monopole antennas, which are used usually in clinical treatments now, is not uniform. The radiation intensity near the root part of the antenna is strong,and near the top part, which is close to affected part, is rather weak. The suggests that monopole antenna was inefficient and was not ideal as a microwave antenna for in body. For the helical antenna, however near the top part the radiation intensity was rather strong, and the radiation was concentrative and efficient. Experiment results and many clinical examples suggest that the helical microwave antenna is a dependable, stable, safe and efficient one, and has a wide applicant future in clinical practice..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2002
- Vol. 21, Issue 4, 297 (2002)
3 MM BAND IF-SWITCH RADIOMETER
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A 3 mm band IF switch radiometer was proposed.On the basis of discussing the theory as well as circuit structure and features,the performance of experimental prototype was presented.The research and experiment results show that not only its stability is better than that of total power radiomenter,but its cost and size A 3 mm band IF switch radiometer was proposed.On the basis of discussing the theory as well as circuit structure and features,the performance of experimental prototype was presented.The research and experiment results show that not only its stability is better than that of total power radiomenter,but its cost and size are just similar to the latter because of absence of 3 mm band switch.It can surely meet the need of practical use..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2002
- Vol. 21, Issue 4, 302 (2002)
MULTIRESOLUTION FUZZY EDGE DETECTION BASED ON PYRAMID STRUCTURE
[in Chinese], [in Chinese], and [in Chinese]
A new unsupervised multiresolution edge detection technique was presented,which combines the morphological filtering,pyramid data structure and fuzzy technique.The algorithm first constructed a pyramid by morphological filtering,then it considered the parent child linking relationship of edge nodes between the two adjaA new unsupervised multiresolution edge detection technique was presented,which combines the morphological filtering,pyramid data structure and fuzzy technique.The algorithm first constructed a pyramid by morphological filtering,then it considered the parent child linking relationship of edge nodes between the two adjacent levels as fuzzy model.Via this model,the coarse and low resolution edge map was propagated and refined in the pyramid,thus the map with fine and high resolution edge was obtained.Finally,some experiments on synthetic and real world images were given with satisfactory results..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2002
- Vol. 21, Issue 4, 305 (2002)
8 MM-BAND DIRECT DETECTION RECEIVER
[in Chinese], and [in Chinese]
A 8mm band MMIC direct detection receiver was proposed on the background of bomb borne MMW radiometer. On the basis of the working principle of this system, main parameters of the system were analyzed and designed. Principle experimental results show that the radiometer has favorable performances, such as high sensitivA 8mm band MMIC direct detection receiver was proposed on the background of bomb borne MMW radiometer. On the basis of the working principle of this system, main parameters of the system were analyzed and designed. Principle experimental results show that the radiometer has favorable performances, such as high sensitivity and small volume..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2002
- Vol. 21, Issue 4, 310 (2002)
Rapid synthesis of nanocrystalline Bi4Ti3O12 by chemical solution decomposition technique
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
By using Bi(NO 3) 3·5H 2O and Ti(OC 4H 9) 4 as raw materials nanocrystalline Bi 4Ti 3O 12 was successfully synthesized by chemical solution decomposition(CSD) technique.The nanocrystallite was preliminarily studied by X ray diffraction(XRD)and transmission electron microscopy(TEM).Based on the anthors′ investigatiBy using Bi(NO 3) 3·5H 2O and Ti(OC 4H 9) 4 as raw materials nanocrystalline Bi 4Ti 3O 12 was successfully synthesized by chemical solution decomposition(CSD) technique.The nanocrystallite was preliminarily studied by X ray diffraction(XRD)and transmission electron microscopy(TEM).Based on the anthors′ investigations,the layered structure of Bi 4Ti 3O 12 was observed,and it was found that nanocrystalline Bi 4Ti 3O 12 has club shaped structure..
Journal of Infrared and Millimeter Waves
- Publication Date: Jan. 01, 1900
- Vol. 21, Issue 4, 314 (2002)
A KIND OF RECOGNITION METHOD OF RADAR TARGET BASED ON MULTI-TRANSFORM
[in Chinese], and [in Chinese]
A recognition method of radar target was presented by using multi transform. First, target 1 D range profile was obtained by FFT. Then the Mahalanobis range of 1 D range profile was calculated. Then the target characteristics were extracted by wavelet transform, in which the data of Mahalanobis range were compressed. TA recognition method of radar target was presented by using multi transform. First, target 1 D range profile was obtained by FFT. Then the Mahalanobis range of 1 D range profile was calculated. Then the target characteristics were extracted by wavelet transform, in which the data of Mahalanobis range were compressed. The experiments of recognition using the data of three kinds of aircraft models were performed. It demonstrates that the method has high recognition rate..
Journal of Infrared and Millimeter Waves
- Publication Date: Aug. 01, 2002
- Vol. 21, Issue 4, 318 (2002)
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