ISSN 
2007 Vol. 36, No. 4
2007, 36(4): 657-659.
Abstract:
The dependence of refractive index on spin asymmetrical coefficient was deduced based on self-averaging limit model in magnetic thin film materials with giant magnetoresistance effects and a measurement system using Fourier transform infrared spectroscopy was constructed to measure magnetorefractive effects (MRE). The measurement results of spin-valve multilayers Si/PtMn/CoFe/Ru/CoFe/Cu/Co/NiFe showed that MRE can be used to characterize GMR effect of magnetic thin films in infrared region.
The dependence of refractive index on spin asymmetrical coefficient was deduced based on self-averaging limit model in magnetic thin film materials with giant magnetoresistance effects and a measurement system using Fourier transform infrared spectroscopy was constructed to measure magnetorefractive effects (MRE). The measurement results of spin-valve multilayers Si/PtMn/CoFe/Ru/CoFe/Cu/Co/NiFe showed that MRE can be used to characterize GMR effect of magnetic thin films in infrared region.
2007, 36(4): 660-662,669.
Abstract:
The sol-gel derived LiTaO3 thin films were prepared on the substrates of N-type Si (100), P-type Si (111), Quartz, Pt/TiO2/SiO2/Si (100), and Nickel, respectively. The properties of LiTaO3 thin films were measured using XRD and SEM. Experimental results show the doped epoxy resin can improve the uniformity of LiTaO3 thin films and the adhesiveness between LiTaO3 thin films and the substrates. The relation between thin film thickness and substrate effect was studied. The intensive peak of XRD of the Nickel substrate does not appear again when the thickness of LiTaO3 thin film excesses 0.2 μm, and the result shows that the substrates have important influence on the initial crystallization of the LiTaO3 thin film. The XRD results also show only polycrystalline LiTaO3 thin films can be prepared on N-type Si (100), P-type Si (111), and Quartz substrate. The LiTaO3 thin films deposited on the Pt/TiO2/SiO2/Si (100) substrate has a strong (012) plane preferred orientation. The LiTaO3 thin films deposited on the Nickel substrate has a perfect C-axis preferred orientation with a large C-axis orientation degree factor of 0.082.
The sol-gel derived LiTaO3 thin films were prepared on the substrates of N-type Si (100), P-type Si (111), Quartz, Pt/TiO2/SiO2/Si (100), and Nickel, respectively. The properties of LiTaO3 thin films were measured using XRD and SEM. Experimental results show the doped epoxy resin can improve the uniformity of LiTaO3 thin films and the adhesiveness between LiTaO3 thin films and the substrates. The relation between thin film thickness and substrate effect was studied. The intensive peak of XRD of the Nickel substrate does not appear again when the thickness of LiTaO3 thin film excesses 0.2 μm, and the result shows that the substrates have important influence on the initial crystallization of the LiTaO3 thin film. The XRD results also show only polycrystalline LiTaO3 thin films can be prepared on N-type Si (100), P-type Si (111), and Quartz substrate. The LiTaO3 thin films deposited on the Pt/TiO2/SiO2/Si (100) substrate has a strong (012) plane preferred orientation. The LiTaO3 thin films deposited on the Nickel substrate has a perfect C-axis preferred orientation with a large C-axis orientation degree factor of 0.082.
2007, 36(4): 663-665.
Abstract:
The geometry property and work-function change of Sn adsorption on Ni(100) surface are investigated by using the density functional theory (DFT) method of first-principles. Total energy calculations show that the substitutional surface alloy phase in the outermost layer is preferable. The buckling amplitude of the Ni(100)c(2×2)-Sn surface alloy is 0.049 nm. This result is almost identical to that previously reported on the basis of the low-energy alkali-ion scattering and low-energy electron diffraction (LEED) study (0.044±0.005 nm), and agrees well with the theoretical result using the full potential linearized augmented plane wave (FLAPW) method(0.036 nm). Unfortunately, there is a big difference between our result and earlier observations by constant-energy-loss electron-energy-loss holography (0.09 nm) and theoretical value of 0.018 nm based on CASTEP program. The work-function change due to Sn adsorption is found to be 0.31 eV, indicating the charge transfer from the substrate to the adsorbate.
The geometry property and work-function change of Sn adsorption on Ni(100) surface are investigated by using the density functional theory (DFT) method of first-principles. Total energy calculations show that the substitutional surface alloy phase in the outermost layer is preferable. The buckling amplitude of the Ni(100)c(2×2)-Sn surface alloy is 0.049 nm. This result is almost identical to that previously reported on the basis of the low-energy alkali-ion scattering and low-energy electron diffraction (LEED) study (0.044±0.005 nm), and agrees well with the theoretical result using the full potential linearized augmented plane wave (FLAPW) method(0.036 nm). Unfortunately, there is a big difference between our result and earlier observations by constant-energy-loss electron-energy-loss holography (0.09 nm) and theoretical value of 0.018 nm based on CASTEP program. The work-function change due to Sn adsorption is found to be 0.31 eV, indicating the charge transfer from the substrate to the adsorbate.
2007, 36(4): 666-669.
Abstract:
The conducting polymer Poly 3,4-Ethylene Dioxy Thiophene (PEDT) thin films was prepared by chemical polymerization. Fourier transform infrared and Scanning Electron Microscope (SEM) were used to characterize its optical property and morphology. A gas sensor using PEDT thin film was fabricated with the assistance of interdigitated electrodes. The sensitivities of the prepared sensor to toxic NO2 and NH3 and its temperature property were studied. Results show that PEDT thin film sensor is very sensitive to NO2 and NH3 of low concentrations. And the sensitive mechanisms of PEDT thin film to toxic gases NO2 and NH3 were also discussed in detail in the paper.
The conducting polymer Poly 3,4-Ethylene Dioxy Thiophene (PEDT) thin films was prepared by chemical polymerization. Fourier transform infrared and Scanning Electron Microscope (SEM) were used to characterize its optical property and morphology. A gas sensor using PEDT thin film was fabricated with the assistance of interdigitated electrodes. The sensitivities of the prepared sensor to toxic NO2 and NH3 and its temperature property were studied. Results show that PEDT thin film sensor is very sensitive to NO2 and NH3 of low concentrations. And the sensitive mechanisms of PEDT thin film to toxic gases NO2 and NH3 were also discussed in detail in the paper.
2007, 36(4): 670-672,676.
Abstract:
A novel electroluminescent polymer, Poly (2-Pentyloxy-3,5-Dibromine-1,4-Phenylenevinylene) (PPDBPV) was prepared by the Gilch route. It is so hard to get new precursor by the traditional route because of the inactivation on benzene ring causing by electron withdrawing effect. To resolve the problem, a modified route has been prepared. The polymer and monomers were characterized by 1H-NMR and FT-IR. The synthesis craft had been studied. The maximum Photoluminescence (PL) wavelength of PPDBPV appeared at 650 nm and gave 20 nm red shift comparing with Poly (2-Methoxy-5-Pentyloxy-1,4-Phenylenevinylene) (PMPPV).
A novel electroluminescent polymer, Poly (2-Pentyloxy-3,5-Dibromine-1,4-Phenylenevinylene) (PPDBPV) was prepared by the Gilch route. It is so hard to get new precursor by the traditional route because of the inactivation on benzene ring causing by electron withdrawing effect. To resolve the problem, a modified route has been prepared. The polymer and monomers were characterized by 1H-NMR and FT-IR. The synthesis craft had been studied. The maximum Photoluminescence (PL) wavelength of PPDBPV appeared at 650 nm and gave 20 nm red shift comparing with Poly (2-Methoxy-5-Pentyloxy-1,4-Phenylenevinylene) (PMPPV).
2007, 36(4): 673-676.
Abstract:
Joint design of non-binary Low Density Parity Check (LDPC) code and Hybrid Automatic Repeat Quest (HARQ) is presented for potential application in future satellite tactical data link system. The and performance comparison is evaluated with binary LDPC coded HARQ scheme in term of frame error rate and throughput. Link level simulation results using C++ show that non-binary LDPC code can be integrated into HARQ protocol successful with significant performance gain, especially for chase combining and partial incremental redundancy schemes. Furthermore, non-binary LDPC coded HARQ outperforms the binary one substantially with reasonable complexity increase.
Joint design of non-binary Low Density Parity Check (LDPC) code and Hybrid Automatic Repeat Quest (HARQ) is presented for potential application in future satellite tactical data link system. The and performance comparison is evaluated with binary LDPC coded HARQ scheme in term of frame error rate and throughput. Link level simulation results using C++ show that non-binary LDPC code can be integrated into HARQ protocol successful with significant performance gain, especially for chase combining and partial incremental redundancy schemes. Furthermore, non-binary LDPC coded HARQ outperforms the binary one substantially with reasonable complexity increase.
2007, 36(4): 677-680.
Abstract:
High power amplifier often brings a nonlinear distortion for the orthogonal frequency division multiplexing system in the transmitter. Diagonal Recurrent Neural Network (DRNN) is a modified model of the fully connected recurrent neural network with the advantage in capturing the dynamic behavior of a system. In this paper. DRNN is introduced to compensate transmitted signal before the signal passes the high power amplifier. The algorithm of gradient descent method is developed to train the DRNN, which requires a low amount of Random Access Memory (RAM) and is with much faster convergence speed from a blind start. The simulation shows that the network owns a rapid convergence and a low amount of RAM is required if this recurrent neural network is applied as predistorter.
High power amplifier often brings a nonlinear distortion for the orthogonal frequency division multiplexing system in the transmitter. Diagonal Recurrent Neural Network (DRNN) is a modified model of the fully connected recurrent neural network with the advantage in capturing the dynamic behavior of a system. In this paper. DRNN is introduced to compensate transmitted signal before the signal passes the high power amplifier. The algorithm of gradient descent method is developed to train the DRNN, which requires a low amount of Random Access Memory (RAM) and is with much faster convergence speed from a blind start. The simulation shows that the network owns a rapid convergence and a low amount of RAM is required if this recurrent neural network is applied as predistorter.
2007, 36(4): 681-684.
Abstract:
Based on wireless optical communication characteristics and wireless access techniques, the Media Access Control (MAC) protocol in wireless optical code division multiple access network is presented and studied. In the analysis, background noise, multi-access interference, Avalanche Photo Diode (APD) noise, and thermal noise are taken into account. With Optical Orthogonal Code (OOC), the mathematic model of network throughput is derived and evaluated according to numerical results. Simulation results indicate this MAC protocol can obtain high network throughput. Furthermore, with shorter packet length or longer code length, a better network throughput is obtained.
Based on wireless optical communication characteristics and wireless access techniques, the Media Access Control (MAC) protocol in wireless optical code division multiple access network is presented and studied. In the analysis, background noise, multi-access interference, Avalanche Photo Diode (APD) noise, and thermal noise are taken into account. With Optical Orthogonal Code (OOC), the mathematic model of network throughput is derived and evaluated according to numerical results. Simulation results indicate this MAC protocol can obtain high network throughput. Furthermore, with shorter packet length or longer code length, a better network throughput is obtained.
2007, 36(4): 685-687.
Abstract:
An open-loop timing recovery algorithm based on basis-function decomposition approach is presented in this paper. The algorithm reduces the bias between the received signal and reference signal to half of the symbol period by the correlative computation, then makes exact timing-bias estimate by the angle information extracted from the correlative computation. The algorithm need not extract carrier phase and the complexity is low. Simulation results show it has good estimation precision.
An open-loop timing recovery algorithm based on basis-function decomposition approach is presented in this paper. The algorithm reduces the bias between the received signal and reference signal to half of the symbol period by the correlative computation, then makes exact timing-bias estimate by the angle information extracted from the correlative computation. The algorithm need not extract carrier phase and the complexity is low. Simulation results show it has good estimation precision.
2007, 36(4): 688-691.
Abstract:
Aiming at three stars used to locate the ground radiant point, a precise location model using digital map and WGS-84 coordinate is presented, and an iterative location algorithm for ground target is therefore proposed. The location simulation is made by using simulated three-dimensional relief map, and the theoretical error expression for the location method is deduced, The presented result shows the location simulation is consistent with the error theoretical analysis, and the location error caused by height hypothesis can be effectively decreased.
Aiming at three stars used to locate the ground radiant point, a precise location model using digital map and WGS-84 coordinate is presented, and an iterative location algorithm for ground target is therefore proposed. The location simulation is made by using simulated three-dimensional relief map, and the theoretical error expression for the location method is deduced, The presented result shows the location simulation is consistent with the error theoretical analysis, and the location error caused by height hypothesis can be effectively decreased.
2007, 36(4): 692-695.
Abstract:
To solve the accuracy degradation of wireless location that results from multi-path fading, the paper improves the traditional narrow correlation technology using Teager-Kaiser (TK) operator. The improved technology not only retains the merit of narrow correlator, but also mitigates the short-time delay multi-path fading better. The simulation result shows that the technology proposed in this paper can mitigate the multi-path fading better and improve the accuracy of location.
To solve the accuracy degradation of wireless location that results from multi-path fading, the paper improves the traditional narrow correlation technology using Teager-Kaiser (TK) operator. The improved technology not only retains the merit of narrow correlator, but also mitigates the short-time delay multi-path fading better. The simulation result shows that the technology proposed in this paper can mitigate the multi-path fading better and improve the accuracy of location.
2007, 36(4): 696-698,702.
Abstract:
This paper presents an expression of pulse compressed Linear Frequency Modulation (LFM) signal with I/Q phase error. The influence of the error on the performance of LFM digital pulse compression is analyzed in detail, a theoretical reference for controlling I/Q phase error in radar receiver designing is provided. The theoretical analysis and the simulating result show that the I/Q phase error will badly influence on the ratio between mainlobe and sidelobe of LFM digital pulse compression with window function for restraining the sidelobe.
This paper presents an expression of pulse compressed Linear Frequency Modulation (LFM) signal with I/Q phase error. The influence of the error on the performance of LFM digital pulse compression is analyzed in detail, a theoretical reference for controlling I/Q phase error in radar receiver designing is provided. The theoretical analysis and the simulating result show that the I/Q phase error will badly influence on the ratio between mainlobe and sidelobe of LFM digital pulse compression with window function for restraining the sidelobe.
2007, 36(4): 699-702.
Abstract:
Compared with ordinary chaos systems, hyperchaos systems have excellent security in communication because hyperchaos sequence has better complexity and randomicity. The thought of applying dimension-lowered hyperchaos sequence to spreading-frequency communication is proposed. A dimension-lowered model is designed to generate hyperchaos sequence with well-proportioned stochastic diffusion, then the capability of hyperchaos sequence is analyzed in defail. The sound spreading-frequency modulation model based on hyperchaos random sequence is tested by practical circuit experiments. Measuring results verify the validity of designing thought. Another idea is briefly introduced for the deep research into spreading-frequency secrecy communication technique.
Compared with ordinary chaos systems, hyperchaos systems have excellent security in communication because hyperchaos sequence has better complexity and randomicity. The thought of applying dimension-lowered hyperchaos sequence to spreading-frequency communication is proposed. A dimension-lowered model is designed to generate hyperchaos sequence with well-proportioned stochastic diffusion, then the capability of hyperchaos sequence is analyzed in defail. The sound spreading-frequency modulation model based on hyperchaos random sequence is tested by practical circuit experiments. Measuring results verify the validity of designing thought. Another idea is briefly introduced for the deep research into spreading-frequency secrecy communication technique.
2007, 36(4): 703-705,708.
Abstract:
A novel compression algorithm for weather radar data based on parallel adaptive coding is presented. Considering the specialty of radar data, some efficient pre-processing algorithms for the data such as coordinate transformation algorithm, vector field holding algorithm and scalar filter algorithm are given first. Then the parallel adaptive coding algorithm is used to compress the pre-processed data. Experimental results show that for the weather radar data, the proposed parallel adaptive algorithm achieves good Power Signal to Noise Ratio (PSNR) even in low bit rate.
A novel compression algorithm for weather radar data based on parallel adaptive coding is presented. Considering the specialty of radar data, some efficient pre-processing algorithms for the data such as coordinate transformation algorithm, vector field holding algorithm and scalar filter algorithm are given first. Then the parallel adaptive coding algorithm is used to compress the pre-processed data. Experimental results show that for the weather radar data, the proposed parallel adaptive algorithm achieves good Power Signal to Noise Ratio (PSNR) even in low bit rate.
2007, 36(4): 706-708.
Abstract:
A new multidimensional OCDMA address code is presented. It is based on one dimension ST-OOC by adding polarimeter/depolarimeter respectively to the encoder/decoder to get multidimensional optical CDMA address code. From theoretical analysis, the number of address code can be increased to n times through n polarization directions in one-dimension system. The numerical analysis shows that, in two-dimensional OCDMA system combining ST-OOC and two polarization directions, the proposed coding method can increase the number of simultaneous users, reduce the multi-user interference effectively, and make an efficient reduction of the number of coders and decoders needed.
A new multidimensional OCDMA address code is presented. It is based on one dimension ST-OOC by adding polarimeter/depolarimeter respectively to the encoder/decoder to get multidimensional optical CDMA address code. From theoretical analysis, the number of address code can be increased to n times through n polarization directions in one-dimension system. The numerical analysis shows that, in two-dimensional OCDMA system combining ST-OOC and two polarization directions, the proposed coding method can increase the number of simultaneous users, reduce the multi-user interference effectively, and make an efficient reduction of the number of coders and decoders needed.
2007, 36(4): 709-712.
Abstract:
A novel method to develop a frequency synthesizer with wide frequency coverage, fast frequency switching speed, and low phase noise is proposed. With the proposed method, the high performance of low phase noise and fast frequency hopping speed is achieved by combining Phase Locked Loop (PLL) and mixer. The Phase and Frequency Detector (PFD) current of the PLL is applied to compensate the nonlinear property of Voltage Controlled Oscillator (VCO) and to avoid the degraded performance due to loop instability. By this, a 11.1~13.1 GHz frequency synthesizer with frequency-step 10 MHz and loop bandwidth 600 kHz is developed. Experimental results show that the performance of phase noise is better than -83 dBc/Hz@1 kHz and its frequency hopping time is shorter than 10 μs.
A novel method to develop a frequency synthesizer with wide frequency coverage, fast frequency switching speed, and low phase noise is proposed. With the proposed method, the high performance of low phase noise and fast frequency hopping speed is achieved by combining Phase Locked Loop (PLL) and mixer. The Phase and Frequency Detector (PFD) current of the PLL is applied to compensate the nonlinear property of Voltage Controlled Oscillator (VCO) and to avoid the degraded performance due to loop instability. By this, a 11.1~13.1 GHz frequency synthesizer with frequency-step 10 MHz and loop bandwidth 600 kHz is developed. Experimental results show that the performance of phase noise is better than -83 dBc/Hz@1 kHz and its frequency hopping time is shorter than 10 μs.
2007, 36(4): 713-715,719.
Abstract:
Thermal simulation is one of the design problems for millimeter-wave medium-to-high power amplifiers. Good thermal configurations were performed for the system to ensure that the active devices would be operating below their rated maximum operating temperature. Numerical simulation based on finite element method is an important tool in the thermal analysis of millimeter-wave power amplifiers. A three dimensional thermal model of a 6 W solid-state integrated power amplifier which is combined by using 1×4 monolithic millimeter-wave integrated circuit (MMIC) chips at Ka-band was built with ANSYS to calculate the temperature distribution under air free convection condition. Good agreement between simulation and experiment and which demonstrated the effectiveness of the thermal model. The simulated results provide a theoretical basis for thermal design of millimeter-wave power amplifiers.
Thermal simulation is one of the design problems for millimeter-wave medium-to-high power amplifiers. Good thermal configurations were performed for the system to ensure that the active devices would be operating below their rated maximum operating temperature. Numerical simulation based on finite element method is an important tool in the thermal analysis of millimeter-wave power amplifiers. A three dimensional thermal model of a 6 W solid-state integrated power amplifier which is combined by using 1×4 monolithic millimeter-wave integrated circuit (MMIC) chips at Ka-band was built with ANSYS to calculate the temperature distribution under air free convection condition. Good agreement between simulation and experiment and which demonstrated the effectiveness of the thermal model. The simulated results provide a theoretical basis for thermal design of millimeter-wave power amplifiers.
2007, 36(4): 716-719.
Abstract:
A novel method is presented to synthesize Negative Refractive Index Material (NRIM) by incorporating array of metallic wires into the host media such as ferrimagnet-YIG under an external magnetic bias field. The effective electromagnetic properties of the composite medium are calculated analytically based on the effective medium theory. The results show that the effective permittivity and effective permeability of the composite medium are negative simultaneously in C-band frequency region, and therefore indicate the proposed method to synthesize NRIM is feasible.
A novel method is presented to synthesize Negative Refractive Index Material (NRIM) by incorporating array of metallic wires into the host media such as ferrimagnet-YIG under an external magnetic bias field. The effective electromagnetic properties of the composite medium are calculated analytically based on the effective medium theory. The results show that the effective permittivity and effective permeability of the composite medium are negative simultaneously in C-band frequency region, and therefore indicate the proposed method to synthesize NRIM is feasible.
2007, 36(4): 720-722,736.
Abstract:
Security is the most important principle of block cipher design. This paper analyses security-testing methods of block cipher, and proposes some statistically-testing variables. Finally, the random data with 1 048 576 b is used for the actual security-testing. The result shows that the presented statistically-testing variables agree with testing results and therefore are valuable to security design of block cipher.
Security is the most important principle of block cipher design. This paper analyses security-testing methods of block cipher, and proposes some statistically-testing variables. Finally, the random data with 1 048 576 b is used for the actual security-testing. The result shows that the presented statistically-testing variables agree with testing results and therefore are valuable to security design of block cipher.
2007, 36(4): 723-725.
Abstract:
There are a lot of interaction phenomenon between electromagnetic wave and plasmas. In this paper, propagation characteristics of electromagnetic wave in unbound periodic and magnetized plasma are strictly analyzed in theory, and the dispersion equation is obtained. By numerical calculation, the affection of change of plasma background density and the sinusoidal variation amplitude value of plasma density on propagation characteristics of electromagnetic wave is analyzed. The results of calculation presents that the effect of change of plasmas density on two characteristic wave (right hand wave and left hand wave) is different. The change of sinusoidal amplitude value of plasma density has a poor effect on the cut off frequency of right hand wave and left hand wave, however, plasma background density has a big effect on the cut off frequency of right hand wave and left hand wave. Meanwhile, this system is a periodic slow wave system in which slow wave is found and may make some important effects on bean-wave interaction.
There are a lot of interaction phenomenon between electromagnetic wave and plasmas. In this paper, propagation characteristics of electromagnetic wave in unbound periodic and magnetized plasma are strictly analyzed in theory, and the dispersion equation is obtained. By numerical calculation, the affection of change of plasma background density and the sinusoidal variation amplitude value of plasma density on propagation characteristics of electromagnetic wave is analyzed. The results of calculation presents that the effect of change of plasmas density on two characteristic wave (right hand wave and left hand wave) is different. The change of sinusoidal amplitude value of plasma density has a poor effect on the cut off frequency of right hand wave and left hand wave, however, plasma background density has a big effect on the cut off frequency of right hand wave and left hand wave. Meanwhile, this system is a periodic slow wave system in which slow wave is found and may make some important effects on bean-wave interaction.
2007, 36(4): 726-729.
Abstract:
This article refers to the security of high-voltage filter inductor and the distributed capacitance of the transformer's secondary winding and introduces a phase shifted controlled full-bridge boost topology, which is applicable for high-voltage power supplies. The soft switch process of boost mode is analyzed by time subsection, the theoretically analyzed result is validated with Pspice simulation, then the boost circuit and buck mode are compared with resistant voltage trait of output filter inductor, cross regulation capability of multi-route output and transformer's magnetic unbalanced issue. The research indicates that the boost mode phase shifted controlled full-bridge converter performs better in cross regulation capability and the self-control of transformer's magnetic unbalanced issue, which is suitable for high-voltage applications.
This article refers to the security of high-voltage filter inductor and the distributed capacitance of the transformer's secondary winding and introduces a phase shifted controlled full-bridge boost topology, which is applicable for high-voltage power supplies. The soft switch process of boost mode is analyzed by time subsection, the theoretically analyzed result is validated with Pspice simulation, then the boost circuit and buck mode are compared with resistant voltage trait of output filter inductor, cross regulation capability of multi-route output and transformer's magnetic unbalanced issue. The research indicates that the boost mode phase shifted controlled full-bridge converter performs better in cross regulation capability and the self-control of transformer's magnetic unbalanced issue, which is suitable for high-voltage applications.
2007, 36(4): 730-732.
Abstract:
An air core pulse transformer is specially designed to provide the high power electron beam and required magnetic field for the high power microwave device simultaneously. First, the primary coils produce the changing magnet field after the primary capacitor discharges. Then a high voltage pulse is induced in the secondary coils to charge the Pulse Form Line (PFL). The magnetic field produced by the primary coils can keep a very high value when the voltage on PFL reaches the required value (not the highest value). Finally, the main switch is triggered when the required value of the voltage on PFL is reached. So the power supply can provides the electron beam and the required guiding magnet field for microwave device simultaneously when it is properly designed.
An air core pulse transformer is specially designed to provide the high power electron beam and required magnetic field for the high power microwave device simultaneously. First, the primary coils produce the changing magnet field after the primary capacitor discharges. Then a high voltage pulse is induced in the secondary coils to charge the Pulse Form Line (PFL). The magnetic field produced by the primary coils can keep a very high value when the voltage on PFL reaches the required value (not the highest value). Finally, the main switch is triggered when the required value of the voltage on PFL is reached. So the power supply can provides the electron beam and the required guiding magnet field for microwave device simultaneously when it is properly designed.
2007, 36(4): 733-736.
Abstract:
The problem of test generation for sequential circuits belongs to the class of NP-complete problem. Due to its complexity test generation for sequential circuits always focuses on the single-clock circuits. However there are many non-synchronous circuits with multiple clocks or internal clock structures in the industrial applications, which could not be handled as the traditional synchronous circuits. In this paper, an orbicular model is presented which introduce the clock signal to the circuit model for test generation. Then a test generation flow for non-synchronous circuits is built up. By this approach, the non-synchronous circuits can be represented in synchronous models in order to utilize the synchronous sequential test generation directly.
The problem of test generation for sequential circuits belongs to the class of NP-complete problem. Due to its complexity test generation for sequential circuits always focuses on the single-clock circuits. However there are many non-synchronous circuits with multiple clocks or internal clock structures in the industrial applications, which could not be handled as the traditional synchronous circuits. In this paper, an orbicular model is presented which introduce the clock signal to the circuit model for test generation. Then a test generation flow for non-synchronous circuits is built up. By this approach, the non-synchronous circuits can be represented in synchronous models in order to utilize the synchronous sequential test generation directly.
2007, 36(4): 737-739,747.
Abstract:
The kick-out pulse for calibration of sampling oscilloscopes is analyzed by Nose-to-Nose (NTN) method. The mathematic expressions of kick-out pulse parameter are deduced according to diode model of time-varying conductance. The factors influencing the kick-out pulse parameter are discussed. The emulational results show that the weaker the capacity of charging capacitance is, the wider the kick-out pulse spectrum bandwidth is. The asymmetry of diode inductance parameter can widen spectrum bandwidth, but increase overshoot. For the leak of strobe pulse, there exists groove in the kick-out pulse spectral response. Finally, the paper brings forward the requirements of the frequency band and the application condition of the NTN method.
The kick-out pulse for calibration of sampling oscilloscopes is analyzed by Nose-to-Nose (NTN) method. The mathematic expressions of kick-out pulse parameter are deduced according to diode model of time-varying conductance. The factors influencing the kick-out pulse parameter are discussed. The emulational results show that the weaker the capacity of charging capacitance is, the wider the kick-out pulse spectrum bandwidth is. The asymmetry of diode inductance parameter can widen spectrum bandwidth, but increase overshoot. For the leak of strobe pulse, there exists groove in the kick-out pulse spectral response. Finally, the paper brings forward the requirements of the frequency band and the application condition of the NTN method.
2007, 36(4): 740-743.
Abstract:
Based on arithmetic additive generator, a kind of design-for-testability and test strategy for direct-form fine-grained pipelined delayed least mean square adaptive filter is presented. The design improves the circuit testability by insulating the filter building modules and converting registers into scan chains. Reuses of some adders and registers existing in circuit result in the elimination or minimization of the additional hardware overhead for test. The test strategy can detect any combinational stuck-at faults within the circuit basic building cell at-speed and without any degradation of the original circuit performance.
Based on arithmetic additive generator, a kind of design-for-testability and test strategy for direct-form fine-grained pipelined delayed least mean square adaptive filter is presented. The design improves the circuit testability by insulating the filter building modules and converting registers into scan chains. Reuses of some adders and registers existing in circuit result in the elimination or minimization of the additional hardware overhead for test. The test strategy can detect any combinational stuck-at faults within the circuit basic building cell at-speed and without any degradation of the original circuit performance.
2007, 36(4): 744-747.
Abstract:
According to the characteristics of city transportation, on the PC-PLC network platform, adopting an original uniform line control technology to multi-crossroad, we implement an intelligent and coordinative control to the signals of the city traffic trunk line. This control system effectively reduces the latency time of vehicles and increases the traffic flux of the trunk line. Results of the emulation make clear that this method of intelligent control distinctly overmatches that of one-point control to improve traffic capacity, and consequently provides a novel approach to settle city traffic problem.
According to the characteristics of city transportation, on the PC-PLC network platform, adopting an original uniform line control technology to multi-crossroad, we implement an intelligent and coordinative control to the signals of the city traffic trunk line. This control system effectively reduces the latency time of vehicles and increases the traffic flux of the trunk line. Results of the emulation make clear that this method of intelligent control distinctly overmatches that of one-point control to improve traffic capacity, and consequently provides a novel approach to settle city traffic problem.
2007, 36(4): 748-750,754.
Abstract:
A Ethernet-based remote monitoring design of air compressor station is presented in this paper. The operating equipments in the air compressor station can be observed and controlled remotely and intelligently through the designed information transmission network; the operating condition and parameters of the main equipments can be learned in time, so the maintenance of the equipments can be insured. The composition and realization of hardware and the expert system used here are discussed. The development of application software system based on configuration software is introduced. The practical operation shows that the system has the characteristics such as working stably, easy operation, etc. It can meet the requirement in equipment maintenance and wind-supply quality.
A Ethernet-based remote monitoring design of air compressor station is presented in this paper. The operating equipments in the air compressor station can be observed and controlled remotely and intelligently through the designed information transmission network; the operating condition and parameters of the main equipments can be learned in time, so the maintenance of the equipments can be insured. The composition and realization of hardware and the expert system used here are discussed. The development of application software system based on configuration software is introduced. The practical operation shows that the system has the characteristics such as working stably, easy operation, etc. It can meet the requirement in equipment maintenance and wind-supply quality.
2007, 36(4): 751-754.
Abstract:
A built-in self-test scheme is presented for a carry save array multiplier in which an accumulator is designed as a test pattern generator and a response compactor. A modified deterministic test sequence is deduced. Analysis and Experiment results show that all the non-redundant stuck-at faults can be covered. As in current Very Large Scale Integration (VLSI) circuits accumulators commonly exist with multipliers, this scheme can lead to minimum hardware overhead and performance degradation by reusing available accumulators to generate test vectors and compact test responses. Moreover, this scheme can achieve the goal of short test sequences and high fault coverage.
A built-in self-test scheme is presented for a carry save array multiplier in which an accumulator is designed as a test pattern generator and a response compactor. A modified deterministic test sequence is deduced. Analysis and Experiment results show that all the non-redundant stuck-at faults can be covered. As in current Very Large Scale Integration (VLSI) circuits accumulators commonly exist with multipliers, this scheme can lead to minimum hardware overhead and performance degradation by reusing available accumulators to generate test vectors and compact test responses. Moreover, this scheme can achieve the goal of short test sequences and high fault coverage.
2007, 36(4): 755-758.
Abstract:
In this paper, a software model based on PC is developed for the hardware-driving and grey shading technology of Color Super Twisted Nematic-Liquid Crystal Display (CSTN-LCD). The influence of different combinations of Multiple Line Addressing (MLA) arithmetic and grey shading technology are considered. By applying Frame Rate Control (FRC) and Pulse Height Modulation (PHM), the FRC-MLA-PWM scheme for driving CSTN-LCD is validated for high cost-performance ASIC design. It is believed that this scheme will offer a useful reference for Register Transfer Level (RTL) circuit design.
In this paper, a software model based on PC is developed for the hardware-driving and grey shading technology of Color Super Twisted Nematic-Liquid Crystal Display (CSTN-LCD). The influence of different combinations of Multiple Line Addressing (MLA) arithmetic and grey shading technology are considered. By applying Frame Rate Control (FRC) and Pulse Height Modulation (PHM), the FRC-MLA-PWM scheme for driving CSTN-LCD is validated for high cost-performance ASIC design. It is believed that this scheme will offer a useful reference for Register Transfer Level (RTL) circuit design.
2007, 36(4): 759-762.
Abstract:
A novel cluster selection algorithm is proposed in view of network security in this paper. The algorithm capability is enhanced by means of load-balancing. The algorithm is based on graph theory and use Kruskal algorithm to calculate the minimum spanning tree of topological structure of wireless Ad Hoc networks. The group on the minimum spanning tree is then generated and the cost of communication among nodes of the group keeps in a low level. The measure of load-balancing taken by the algorithm can prolong the lifecycle of the group head to maximum and keep stability of the whole network while the new and old Cluster are alternating.
A novel cluster selection algorithm is proposed in view of network security in this paper. The algorithm capability is enhanced by means of load-balancing. The algorithm is based on graph theory and use Kruskal algorithm to calculate the minimum spanning tree of topological structure of wireless Ad Hoc networks. The group on the minimum spanning tree is then generated and the cost of communication among nodes of the group keeps in a low level. The measure of load-balancing taken by the algorithm can prolong the lifecycle of the group head to maximum and keep stability of the whole network while the new and old Cluster are alternating.
2007, 36(4): 763-766.
Abstract:
The embedded Internet based on GPRS and SMS is designed in order to solve the requirement of the environment monitoring system in the agriculture field. The system features the embedded operation system-μC/OS-Ⅱ, the connection with Internet, the function of alarm through SMS, and the customizing SMS in the μC/OS-Ⅱ. The difficulties of the embedded Internet and its solution schemes are given in detail, such as the using and programing technique of the AT dictate in GPRS and SMS etc. The running has shown the wireless remote monitoring system in agriculture based on the embedded Internet has the characteristic of stabilization, credibility, expansile and low costs etc.
The embedded Internet based on GPRS and SMS is designed in order to solve the requirement of the environment monitoring system in the agriculture field. The system features the embedded operation system-μC/OS-Ⅱ, the connection with Internet, the function of alarm through SMS, and the customizing SMS in the μC/OS-Ⅱ. The difficulties of the embedded Internet and its solution schemes are given in detail, such as the using and programing technique of the AT dictate in GPRS and SMS etc. The running has shown the wireless remote monitoring system in agriculture based on the embedded Internet has the characteristic of stabilization, credibility, expansile and low costs etc.
2007, 36(4): 767-770.
Abstract:
Software reliability test is an important way to assure the quality of the software. This paper presents XML test case module and a way to store test cases of software reliability test by using (Extensible Markup Language) XML technology. XML test case file creator and a test engine is implemented. The test case is read by the test driver program, which drives the tested program to run and compares the test result automatically. In this way, the software interface will be tested automatically and efficiently. Test data is divorced from test driver program for maintenance and reuse of the test data.
Software reliability test is an important way to assure the quality of the software. This paper presents XML test case module and a way to store test cases of software reliability test by using (Extensible Markup Language) XML technology. XML test case file creator and a test engine is implemented. The test case is read by the test driver program, which drives the tested program to run and compares the test result automatically. In this way, the software interface will be tested automatically and efficiently. Test data is divorced from test driver program for maintenance and reuse of the test data.
2007, 36(4): 771-774.
Abstract:
A 3-layer model based on Java Authentication & Authorization Service (JAAS) and Struts framework is presented to insure the security of Manufacturer Information System (MIS). In this model, the identical roles for both Database Management System (DBMS) and web container are defined. A coordinate security architecture is utilized to realize the Role-Based Access Control (RBAC) of MIS at web browser, web container and database, respectively. The results indicate that the implementation of this model meets various security requirements for MIS, and also makes it easier to administrate the system security during the runtime. In addition, the Struts framework enhances the development for web application effectively.
A 3-layer model based on Java Authentication & Authorization Service (JAAS) and Struts framework is presented to insure the security of Manufacturer Information System (MIS). In this model, the identical roles for both Database Management System (DBMS) and web container are defined. A coordinate security architecture is utilized to realize the Role-Based Access Control (RBAC) of MIS at web browser, web container and database, respectively. The results indicate that the implementation of this model meets various security requirements for MIS, and also makes it easier to administrate the system security during the runtime. In addition, the Struts framework enhances the development for web application effectively.
2007, 36(4): 775-777.
Abstract:
The solar radiance diffused by a randomly-rough underlying surface might lead to increase sky radiance. The computation of sky radiance resulted from the earth's diffuse reflection is studied based on a hypothesis that a underlying surface is randomly rough. The paper gives an analysis of the method to calculate the reflectivity, average hemisphere reflectivity, and transmission in virtue of the reciprocity law from the earth's surface to the top of the atmosphere. The calculation of the effect of different albedo of underlying surface on sky radiance is made at different viewing zenith angles and compared with the experimental result. The results show that sky radiance rises rapidly as the albedo of the earth's surface becomes big while viewing zenith angle is close to 90°.
The solar radiance diffused by a randomly-rough underlying surface might lead to increase sky radiance. The computation of sky radiance resulted from the earth's diffuse reflection is studied based on a hypothesis that a underlying surface is randomly rough. The paper gives an analysis of the method to calculate the reflectivity, average hemisphere reflectivity, and transmission in virtue of the reciprocity law from the earth's surface to the top of the atmosphere. The calculation of the effect of different albedo of underlying surface on sky radiance is made at different viewing zenith angles and compared with the experimental result. The results show that sky radiance rises rapidly as the albedo of the earth's surface becomes big while viewing zenith angle is close to 90°.
2007, 36(4): 778-780,804.
Abstract:
A high-voltage linear optocoupler is designed, which could transmit analog signals accurately and meet the requirement of high-voltage isolating. It contains a GaAlAs infrared emitting diode optically coupled to a Si-PIN photodiode. The operation principle and the design of circuit are described. The main factors affecting the isolating properties and linearity are analyzed. Measuring results indicate that the device possesses an excellent isolation properties and high linearity.
A high-voltage linear optocoupler is designed, which could transmit analog signals accurately and meet the requirement of high-voltage isolating. It contains a GaAlAs infrared emitting diode optically coupled to a Si-PIN photodiode. The operation principle and the design of circuit are described. The main factors affecting the isolating properties and linearity are analyzed. Measuring results indicate that the device possesses an excellent isolation properties and high linearity.
2007, 36(4): 781-783,812.
Abstract:
Compared with conventional electromagnetic transformer, piezoelectric transformer has many advantages such as compact volume, high step-up ratio, non-flammability, and none-electromagnetic pollution. In this paper, the parameters of equivalent circuit of radial vibration mode piezoelectric transformer are measured through Y-parameter equivalent circuit model using Agilent-4294A impedance analyzer. The values of measurement and model are compared, and the causes of the differences are analyzed. Then the characteristics of variety of step-up ratio, output power, and efficiency with load are simulated and analyzed by turning the measured results into the formula.
Compared with conventional electromagnetic transformer, piezoelectric transformer has many advantages such as compact volume, high step-up ratio, non-flammability, and none-electromagnetic pollution. In this paper, the parameters of equivalent circuit of radial vibration mode piezoelectric transformer are measured through Y-parameter equivalent circuit model using Agilent-4294A impedance analyzer. The values of measurement and model are compared, and the causes of the differences are analyzed. Then the characteristics of variety of step-up ratio, output power, and efficiency with load are simulated and analyzed by turning the measured results into the formula.
2007, 36(4): 784-787.
Abstract:
In laser atmosphere communication technology, the characteristics of the atmosphere channel are very important for the communication system. Atmosphere turbulence causes the undulation of beam intension, the dithering and spreading of beam, etc. These affects of turbulence are analyzed and an experiment system is designed. The experiment results are given and discussed.
In laser atmosphere communication technology, the characteristics of the atmosphere channel are very important for the communication system. Atmosphere turbulence causes the undulation of beam intension, the dithering and spreading of beam, etc. These affects of turbulence are analyzed and an experiment system is designed. The experiment results are given and discussed.
2007, 36(4): 788-790.
Abstract:
An elliptical Gaussian beam, which is from single transverse mode semiconductor laser diodes, can be approximated dealt as circular beam because most elements of optical systems generally consist of circular aperture, like lens, illuminator, reflector, etc. By choosing both proper aperture and distance, the laws of reflection and refraction, ray tracing techniques, etc. from geometrical optics provide a foundation for design of laser beam controlling systems. Applications of these techniques to design an axis-symmetrical beam quality controlling systems are presented in this paper, and measurements with Photon 2 350 Beam Profiler are represented. The angle of divergence is corrected within 1mrad, thus the theories in this paper are proved to be applicable to beam quality controlling system.
An elliptical Gaussian beam, which is from single transverse mode semiconductor laser diodes, can be approximated dealt as circular beam because most elements of optical systems generally consist of circular aperture, like lens, illuminator, reflector, etc. By choosing both proper aperture and distance, the laws of reflection and refraction, ray tracing techniques, etc. from geometrical optics provide a foundation for design of laser beam controlling systems. Applications of these techniques to design an axis-symmetrical beam quality controlling systems are presented in this paper, and measurements with Photon 2 350 Beam Profiler are represented. The angle of divergence is corrected within 1mrad, thus the theories in this paper are proved to be applicable to beam quality controlling system.
2007, 36(4): 791-794.
Abstract:
Nanoparticles of iron oxide and its hydrate were synthesized with hydrothermal method and characterized by infrared, Scanning Electron Microscope (SEM) and soon. The dimensions of the nanoparticles are about 50~120 nm. The form of iron oxide nanoparticles appears to be globosity while its hydrate rod. Amino acids intermingling with the synthesized nanoparticles were crystallized to investigate the space effect of the nanoparticles. The crystalline forms of crystal are different from those of pure amino acid. The positions and width of the nanoparticles'peaks in the infrared spectrum change too. Microscope observation and infrared spectrum results indicate the nanoparticles have changed the internal structure of amino acids crystal. 3-(4, 5-dimethythiazol 2-yl)-2,5 diphenyltetrazolium bromide (MTT) assay was used to determine their cytotoxicity. The Optical Density (OD) value was used to calculate Relative Generation Rate (RGR) of cells. The RGRs of nanoparticles of iron oxide and its hydrate are about 70%~95%, the grades of cytotoxicity are 1~2. This result indicates they just have low toxicity.
Nanoparticles of iron oxide and its hydrate were synthesized with hydrothermal method and characterized by infrared, Scanning Electron Microscope (SEM) and soon. The dimensions of the nanoparticles are about 50~120 nm. The form of iron oxide nanoparticles appears to be globosity while its hydrate rod. Amino acids intermingling with the synthesized nanoparticles were crystallized to investigate the space effect of the nanoparticles. The crystalline forms of crystal are different from those of pure amino acid. The positions and width of the nanoparticles'peaks in the infrared spectrum change too. Microscope observation and infrared spectrum results indicate the nanoparticles have changed the internal structure of amino acids crystal. 3-(4, 5-dimethythiazol 2-yl)-2,5 diphenyltetrazolium bromide (MTT) assay was used to determine their cytotoxicity. The Optical Density (OD) value was used to calculate Relative Generation Rate (RGR) of cells. The RGRs of nanoparticles of iron oxide and its hydrate are about 70%~95%, the grades of cytotoxicity are 1~2. This result indicates they just have low toxicity.
2007, 36(4): 795-797.
Abstract:
The possibility and efficiency of a way by the Empirical Mode Decomposition (EMD), a recently popular signal analysis method, to check the position of QRS in an ECG is discussed in this paper. The result displays that the high frequency parts of Intrinsic Mode Functions (IMF) in the ECG are effective to separate the feature point of QRS from the ECG. That is verified by standard signals and the accurate rate is relatively high.
The possibility and efficiency of a way by the Empirical Mode Decomposition (EMD), a recently popular signal analysis method, to check the position of QRS in an ECG is discussed in this paper. The result displays that the high frequency parts of Intrinsic Mode Functions (IMF) in the ECG are effective to separate the feature point of QRS from the ECG. That is verified by standard signals and the accurate rate is relatively high.
2007, 36(4): 798-800.
Abstract:
Based on the model of Ultrasonic signals, this paper designs a frequency-dependent compensation filter to solve the problem, which is the ultrasonic signals' absorb attenuation become higher with the far transmission depth and higher frequencies when transmitting in a tissue. We also transform the operation from the frequency to time to avoid big operation. At the same time, we combine the dynamic filter technique which chose different passband with different depth to hold the high signal-to-noise ratio.
Based on the model of Ultrasonic signals, this paper designs a frequency-dependent compensation filter to solve the problem, which is the ultrasonic signals' absorb attenuation become higher with the far transmission depth and higher frequencies when transmitting in a tissue. We also transform the operation from the frequency to time to avoid big operation. At the same time, we combine the dynamic filter technique which chose different passband with different depth to hold the high signal-to-noise ratio.
2007, 36(4): 801-804.
Abstract:
A new approach to the problem of machine part image recognition is proposed by using maximization of mutual information. The method applies entropy to measure image feature, combined with color information and local shape information, and uses mutual information as a new matching criterion between the images for image recognition. This method solves the problem that histogram algorithm can not represent the spatial information. This method not only has the feature of translation invariant, but also avoids image segmentation which may lead to a complex calculation, so it can be realized easily. The result shows that proposed approach is accuracy, stability, and reliability in the processing of machine part image recognition.
A new approach to the problem of machine part image recognition is proposed by using maximization of mutual information. The method applies entropy to measure image feature, combined with color information and local shape information, and uses mutual information as a new matching criterion between the images for image recognition. This method solves the problem that histogram algorithm can not represent the spatial information. This method not only has the feature of translation invariant, but also avoids image segmentation which may lead to a complex calculation, so it can be realized easily. The result shows that proposed approach is accuracy, stability, and reliability in the processing of machine part image recognition.
2007, 36(4): 805-808.
Abstract:
Based on the analysis of gear pump structure and capability, the wavelet transform method is proposed to detect the fault information in the pressure signal from the outlet port of the pump. According to simulation, the third level wavelet coefficients decomposed from the pressure signal in fault state are significantly different from those in normal state and can be used to effectively diagnose whether the working state of gear pump is normal or not. The results show that the wavelet transform is a practical method for fault analysis of gear pump.
Based on the analysis of gear pump structure and capability, the wavelet transform method is proposed to detect the fault information in the pressure signal from the outlet port of the pump. According to simulation, the third level wavelet coefficients decomposed from the pressure signal in fault state are significantly different from those in normal state and can be used to effectively diagnose whether the working state of gear pump is normal or not. The results show that the wavelet transform is a practical method for fault analysis of gear pump.
2007, 36(4): 809-812.
Abstract:
Multi-Agent System (MAS) designing has faced some challenging work such as cooperation among agents which are vital to the performance of this system. A much advanced agent role-value method based upon Q-learning is proposed in this paper to avoid the unstabilizing factors and the loss of efficiency caused by possibility of too frequent role switching between robots. Other new methods based on this role model are suggested to solve the problems associated with system designing and implementation. Application to Federation of International Robot-Soccer Association (FIRA) simulation system proves that this method is effective, and reduces the possibility that the robots loss ball, fumble ball and nonfeasance, and remedies the shortage that roles are assigned according to fixed regions.
Multi-Agent System (MAS) designing has faced some challenging work such as cooperation among agents which are vital to the performance of this system. A much advanced agent role-value method based upon Q-learning is proposed in this paper to avoid the unstabilizing factors and the loss of efficiency caused by possibility of too frequent role switching between robots. Other new methods based on this role model are suggested to solve the problems associated with system designing and implementation. Application to Federation of International Robot-Soccer Association (FIRA) simulation system proves that this method is effective, and reduces the possibility that the robots loss ball, fumble ball and nonfeasance, and remedies the shortage that roles are assigned according to fixed regions.
2007, 36(4): 813-816.
Abstract:
The intrinsic value of common stocks is analyzed by combining The Analytic Hierarchy Process (AHP) and principal component analysis. The method is applied to several stocks as an illustration and is found to be dependable at computing the intrinsic values of stocks. For those small investors who make investment decisions based on intrinsic values, the result of this paper may be used as a guidance. According to example of calculating used, level analysis and factor method combined together to analyze can calculate the inherent value score of the stock well, it is a feasible analytical method.
The intrinsic value of common stocks is analyzed by combining The Analytic Hierarchy Process (AHP) and principal component analysis. The method is applied to several stocks as an illustration and is found to be dependable at computing the intrinsic values of stocks. For those small investors who make investment decisions based on intrinsic values, the result of this paper may be used as a guidance. According to example of calculating used, level analysis and factor method combined together to analyze can calculate the inherent value score of the stock well, it is a feasible analytical method.
