Abstract:Due to the rapid development of ultrafast laser technology，semiconductor technology and electronics，stable and reliable THz sources and detectors become available，which leads to flourish for Terahertz science and technology. This article describes the work carried out by major U.S. nuclear weapons laboratories and other national laboratories. The development trends of terahertz science and technology are analyzed as well. The possible applications of THz technologies are discussed in the research of weapon physics，including the characterization and the tuning of materials under extreme conditions，energetic materials chemical kinetics，and ultrafast diagnosis of shock wave and detonation physics.

Abstract:As the electromagnetic radiation between infrared and millimeter waves，Terahertz wave is in the transition area from electronics to optical，which bears the characteristics of both the penetrability of microwave and high resolution of infrared imaging. Therefore, it is suitable to enormous potential applications in military fields including radar, broadband communication，security detection and remote reconnaissance. The characteristics of THz imaging radar technology are introduced in this paper. Combined with the application requirements of the missile guidance and the technical development status，the feasibility of THz imaging radar technology used in guidance is analyzed. The related problems are discussed as well.

Abstract:Tracking Telemetry and Command(TT&C) for near space hypersonic spacecraft needs to solve blackout，over-the-horizon and multi-target problems. According to the characteristics that Terahertz waves can penetrate the plasma and are attenuated intensively in the atmosphere，the Terahertz TT&C system based on airborne platform including aeroplane and airship is researched. The Terahertz system can accomplish integrated function of velocity measurement，ranging，telemetry and telecommand by using spread spectrum technology；and tracking telemetry and command for multi-target can be realized as well. The ballistic measurement of hypersonic spacecraft can be implemented by using nR (n≥3) method. The analysis results indicate that the technology solutions for air-borne Terahertz spread spectrum TT&C system are reasonable，while there are significant differences for engineering application.

Abstract:There are rigorous requirements on the characteristic of electron beams in Free Electron Laser(FEL) operation, such as high brightness and high average current. High voltage DC electron gun with photo-cathodes has become the first choice for generating the beams. A high voltage DC electron gun is designed to work stably at 350 kV. The software of the control system is developed in VC++ 6.0 for DC gun. The experimental results indicate that the control software can be operated easily with friendly interface and rapid response speed. It can provide support for the high-voltage aging of electron gun and system evaluation due to its good reliability and stability.

Abstract:In the design of 0.22 THz Folded Waveguide Traveling-Wave Tube(FWG-TWT) which acts as an amplifier in terahertz sources，a magnetic focusing system is employed to ensure the beam from the electron gun moving into the beam-wave interaction region with high passing rate. The paper studies two kinds of magnetic focusing system，including solenoid and Periodic Permanent Magnet(PPM). Three-dimensional software is used to simulate the model and analyze how such parameters as magnetic pole position，period，flux density，even magnet pole’s thickness determine the beam’s transmission. The results show that the static passing rate of electron beam in the tunnel can almostly achieve 100%，with a small oscillating range of beam.

Abstract:Ultraviolet Lithographie，Galvanoformung and Abformung(UV-LIGA) is an attractive technique to fabricate THz vacuum electron devices including resonance cavities，electron beam tunnels and output waveguides. This paper studies the effects of the softbake，the exposure dosage and the postbake on SU8 models，highlighting the effect of the exposure dosage and its mechanics，and then obtains the optimized process parameters. The methods of SU8 removal are studied as well，and a 340 GHz all-copper Folded Waveguide(FWG) Slow Wave Structure(SWS) is fabricated.

Abstract:A multi-beam double vane Slow-Wave Structure(SWS) with half-period-stagger is presented，which is used to generate Terahertz(THz) continuous and high power wave. By analyzing the cold dispersion characteristics and axial field distributions of the novel SWS，it indicates that increasing the number of sheet beams will increase the current of beam with the same cold dispersion characteristics，and the SWS shows a high electrical efficiency at high frequencies. The process of the beam-wave interaction of structure is simulated with PIC code at 300 GHz. The simulated results show that the power gains of adjacent channels are both 20 dB under identical operating conditions, which means this novel type of SWS can operate in parallel with multiple beams，therefore the output power of device can be increased.

Abstract:The study of High Electron Mobility Transistor(HEMT) devices is very important in many fields and is also of great significance for promoting the application of terahertz. In this paper, the structure of a double δ-doped GaAs HEMT has been analyzed. Multi-layer structure of a doubleδ-doped GaAs HEMT，which contains the buffer layer, the channel layer, the planar doped layer, the isolation layer and so on, is prepared by molecular beam epitaxy. The multi-layer structure has been studied using X-ray diffraction and transmission electron microscopy. Results of the Hall measurement indicate that the sheet density and mobility of 2DEG are 1.82×1012 cm-3 and above 6 520 cm2? V-1?s-1，respectively.

Abstract:Many states navies are developing submarine electronic reconnaisance systems to meet the need of littoral military operation, and to respond the threat of non-acoustic anti-submarine detector. The characteristics of the modern submarine electronic reconnaissance system are summarized by analyzing the technical characteristics of typical active foreign military submarines. In consideration of the research status of electronic reconnaissance technologies, the trends of submarine radar reconnaissance system are researched.

Abstract:This paper is focused on two Non-Data Aided(NDA) timing recovery algorithms for burst Gaussian Minimum Shift Keying(GMSK) demodulation with small Bandwidth Time(BT). Performance of each algorithm is studied by Matlab simulation. It is demonstrated that the joint phase and timing synchronization exhibits great performance under small BT values，and its timing Minimum Square Errors(MSE) can be lower than 1×10ˉ3 under EbN0≥12 dB；while the performance of joint frequency and timing algorithm is outstanding when the frequency bias is above 1%. The selection of algorithm to be used depends on the application requirements in practical engineering.

Abstract:Aiming at the problem of the asynchronous arrival at receiving antennas caused by the distributed location of transmit antennas, a transmission and detection technique is presented for distributed Multiple Input Multiple Output(MIMO) system with V-BLAST(Vertical Bell Labs Layered Space Time) architecture. In slowly fading channel, an equal diagonal upper triangular channel is constructed based on the Geometric Mean Decomposition(GMD) method by making use of the feedback channel state information to eliminate the imbalance among subchannel gains. The simulation results under Ricean fading conditions show that, compared with QR decomposition algorithm, the proposed detection technique can improve the BER performance remarkably.

Abstract:A communication network based on an embedded Ethernet and RS-422 multi-machine communication network is presented in this paper. The data conversion between Ethernet and RS-422 multi-machine communication network is realized. The real-time controlling is realized on the output frequency and power of a remote multiple Frequency Synthesizer(FS). Moreover, the voltage, current, temperature, output power, and lock status are monitored in real-time as well.

Abstract:Considering the low precision of traditional Cell-identity(ID) algorithm，this paper proposes a new algorithm of Cell-ID location and tracking. The proposed algorithm makes use of current Base Station(BS) and the adjacent BS，and calculates the likelihood vectors using different weight coefficients. The motion states of Mobile Station(MS) are obtained through Hidden Markov Model(HMM)，and the position of MS is determined. The experimental results show that the algorithm bears good location performance in stable serving BS with low complexity，which meets the location requirements of Federal Communications Commission(FCC).

Abstract:A new model reuse method of flight control system virtual prototype is proposed Based on the Systems Modeling Language(SysML) Components(BSC), namely US-BP(Unit, Structure; Behavior, Process) method, which can improve the methods of virtual prototype-oriented system analysis and description. Taking a certain type of four-rotor UAV as example, the implementation of the flight control system virtual prototype supporting model reuse is described—the simulation, design and implementation are based on SysML components and Simulink components simultaneously. It provides an important technology for the model reuse in the modeling and simulation of the flight control system.

Abstract:Aiming at the uplink multiuser Multiple Input Multiple Output(MIMO) system，a new algorithm is proposed with the maximum Signal-to-Interference Noise Ratio(SINR) guideline for Multiple Access Interference(MAI) suppression. The algorithm makes full use of the Channel State Information(CSI) to design a filter to suppress multiple access interference caused by multiple access interference and noise. In comparison with Block Diagonalization(BD) algorithm，the proposed algorithm takes the influence of noise into account，and its performance is greatly improved. The algorithm under imperfect channel scenarios is modified, and it exhibits good performance in the simulation results.

Abstract:This paper researches a Primary Synchronization Signal(PSS) timing synchronization algorithm for downlink of Long Term Evolution(LTE) system. The conventional PSS timing algorithm applies the matched filter method to received signals and the local PSS in time domain, therefore its computational complexity is large. A partition frequency domain correlation algorithm is proposed, which performs the detection by through dividing the received signal into several parts and transforming these parts to frequency domain by FFT. Simulation results under multi-path conditions show that, compared with the conventional algorithm, the proposed algorithm can get comparative performance and cut the computational complexity by about 94% with the space between two adjacent parts of 512.

Abstract:Aiming at the problems in existing underground personnel positioning systems, an assisted positioning method based on pedestrian dead reckoning is proposed. Low-cost Inertial Measurement Unit(IMU) and magnetometer are employed to constitute a stable Attitude Heading Reference System (AHRS). The theory of inertial navigation is utilized, an algorithm for step detection is described, and Zero velocity Update(ZUPT) is adopted for velocity and position estimation to compose a pedestrian dead reckoning system. An experiment is performed in the corridor of a laboratory building to emulate the underground mine road environment. The experimental results demonstrate that the dead reckoning performs well and this method is an effective complement to existing underground positioning by improving the positioning accuracy.

Abstract:The single laser wave front aberration caused by reflection mirror in the coherent laser communication is studied. The wave front mismatch caused by the signal to local oscillator field coherence in coherent laser communication systems is analyzed. The simulation result shows that the Peak to Valley(PV) is the main factor which causes the performance decline of laser communication system, while the size of reflection mirror aberration influences the system insignificantly.

Abstract:A microwave GaAs transistor rectifier at 2.45 GHz based on microstrip lines is presented in this paper. The GaAs transistor has enhanced the rectifier power capacitance greatly. The proposed rectifier bears a power to weight ratio much higher than conventional rectifiers based on Schottky diodes. The measured results show that the rectifier achieves 41% of its highest rectifying efficiency when the input microwave power reaches 30 dBm and the DC load is 38 Ω；the rectifier reaches its highest DC output power 28.7 dBm with an input microwave power at 34 dBm and a DC load of 23 Ω. The GaAs transistor rectifiers will be applied to microwave power transmission systems with strict power to weight ratio requirements. The rectifiers may own higher conversion efficiency with improved circuit design and can be applied to high power to weight rectennas.

Abstract:Millimeter/sub-millimeter limb sounder plays an important role in atmospheric science, environmental science and global climate change research. Millimeter/sub-millimeter limb sounding radiometer usually needs to operate in multiple frequency bands, such as multi-band of feed，therefore its bandwidth can not meet the requirements usually. When multiple detection bands share a primary mirror, using quasi-optical technology to achieve the detection of frequency separation can save a lot of space. The combination of quasi-optical polarization wire grid and quasi-optical frequency selector can be used to separate four bands of frequency ranging from 118 GHz to 340 GHz. Quasi-optical polarization wire grid is a quasi-optical power divider/combiner，which separates the four bands signals into 183 GHz/240 GHz and 118 GHz/340 GHz; while quasi-optical frequency selector is a high frequency selective surface, which can transmit high-frequency electromagnetic waves and reflect low frequency electromagnetic waves. Reflected and transmitted electromagnetic waves enter into two receiving modules to achieve signal reception. In this paper, the structural parameters are simulated and optimized in HFSS for the periodic unit. The quasi-optical polarization wire grid and quasi-optical frequency selector technology are implemented according to simulation results. The practically measured results are consistent to the design requirements of millimeter/sub-millimeter limb sounding instrument.

Abstract:A comprehensive study of the Dynamic Framed Slotted ALOHA(DFSA)-based anti-collision multi-tag identification algorithms for passive Radio Frequency Identification(RFID) system is performed, and the tag estimation techniques are sequential weighted. Performance of DFSA algorithms before and after the improvements is compared through extensive simulation and the optimal forgetting factor is determined. The improvements can shorten the time required for identifying tags to improve the work efficiency of the RFID system. It can be effectively applied to container management, logistics management of ports, railway stations or logistics center, and solve the problems of slow goods flow or congestion caused by the multi-tag collision in RFID systems.

Abstract:Nowadays，human errors do exist in bus station manual reporting，which brings a lot of inconvenience to public travel and bus running. A new automatic bus stop reporting system is designed by combining Radio Frequency Identification(RFID)，Micro Controller Unit(MCU) control technology，digital voice technology，and Light Emitting Diode(LED) display technology. Both the overall structure of the system hardware and the software design are given. The proposed system can implement intelligent bus stop reporting，which makes the work of drivers easier than before, and improves the security of the bus running as well as the accuracy of the bus stop reporting. The system possesses practical value and wide application prospects due to its simple structure.

Abstract:By analyzing the characteristics of the glass insulator and its defects in aerial images of the unmanned aerial vehicle inspection system, a method is presented to extract glass insulator and detect defects. The OTSU's thresholding method is applied to H and S components in Hue,Saturation,Intensity (HSI) color space for image segmentation; and then, the distribution of the contours' angle and area is calculated by using the histogram method to obtain the position of glass insulators accurately. Feature detection algorithm is proposed to detect the glass insulators and mark out the defects. Experimental results indicate that the method can mark the location of the defects accurately in the aerial images with natural background, which has a good practical value.

Abstract:A new fusion method based on Compressed Sensing(CS) is proposed to solve storage and computation cost problems in traditional image fusion algorithms. Sparse representation coefficients of source images are obtained on the basis of overcomplete two-dimensional Discrete Cosine Transform(DCT) dictionary. Then the observed values which will be fused are got by applying random projection on the coefficients. The weights of each image block are calculated adaptively based on standard deviation method. Thus input image measurements are fused into composite measurements via weighted averaging. The fused image is reconstructed through improved gradient pursuit with modified stepsize. The simulation results show that, comparing with other fusion algorithms, the proposed method can achieve better performance on fusion results with less sampling numbers and low computational complexity.

Abstract:Due to the instability and the limited precision of traditional natural gradient Independent Component Analysis(ICA) algorithm to extract frequency shift track circuit Frequency-Shift Keying(FSK) signals，a kind of variable step-size natural gradient ICA algorithm is proposed based on whitening. According to the orthogonal constraint satisfied by separation matrix during whitening process, a kind of single-step orthogonal correction instead of whitening process is introduced. Then，a kind of single-step error estimation function is put forward based on the generalized degree of approximation between the separation matrix of each iteration and the optimal separation matrix. A nonlinear function is designed based on whitening to be the step-size adjusting function according to this error estimation. Simulation experiments indicate that the variable step-size natural gradient ICA algorithm based on whitening bears more stable and accurate de-noising performance for the detection and extraction of FSK signals compared with traditional natural gradient ICA algorithm.

Abstract:A new shape descriptor with fusion contour and region information is proposed in order to represent the shape characteristics of the image more accurately. Apply two-dimensional Discrete Cosine Transform(DCT) to obtain the low-frequency coefficients as regional characteristics. Then extract and sample the contours of image, and get the ordered list of points. Track each sampling point equidistantly clockwise and counterclockwise to get two adjacent points, and calculate the arch-height and centroid distance. Construct a complex function of arch-height and centroid distance, and obtain the DCT coefficients, then combine regional and contour features. Retrieval experiments on MPEG-7 shape database show that, the retrieval performance of this descriptor is better than that of the triangle area function, the centroid distance function, and arch-height radius complex function significantly.

Abstract:A mixed feed-forward control method based on T-S fuzzy model combined with pulse jet and pressure fluctuation feed-forward is proposed to decrease the timing disturbance on the negative pressure of wind dust removal pipeline caused by pulse jet in flat bag dedusting system. The proposed method is applied in the practical production environments with concentrated wind power processes in Shandong and other provinces. The operation results indicate that, it can effectively weaken the disturbance on pipeline negative pressure caused by pulse jet, and simplify the control with good stability and robustness.

Abstract:Attribute delay is the key factor which affects applicability and feasibility of the High Level Architecture(HLA) simulation system. Since Run-Time Infrastructure(RTI) attribute delay is difficult to achieve and reflect HLA system performance, a testing method for HLA system attribute delay is proposed. Time management setting which meets simulation system’s requirements is elaborated. An improved program is adopted to avoid the tick’s inefficiency. The simulation testing result indicates that the proposed method is easy and feasible.

Abstract:Based on the strong function of TestStand and the integrated auto test environment, performance and index auto test program is developed for each sub-equipment. The status of each sub-equipment can be known exactly in the R&D, production and maintenance of the equipment. A detection method is provided for the maintenance of sub-equipment as well. Compared with previous test method, the proposed auto test system makes the detection of sub-equipment quickly, simply and high efficiently.

Abstract:Hot metal silicon content has long been used as one of the most important indices to represent the hot metal quality and the thermal state of a blast furnace. In order to improve the measurement precision and attain stable operation of the blast furnace, a novel model for predicting silicon content by using Least Square Support Vector Machine(LSSVM) is presented. It adopts Genetic Algorithm(GA) to determine the optimum parameter set and therefore improves the model performance. By training and testing the operational data from blast furnace at a steel tube plant, the experimental results indicate that the proposed model can predict silicon content in hot metal with a maximum relative error of 5.8 % and correlation coefficient of 0.926 375, whose accuracy can be improved by 2.1% and 4.3% than that of the direct LSSVM and the feed-forward network with the same data set, respectively.

Abstract:Among variety THz application systems, the THz mixer is a key component of the receiver front-end, and the Schottky diode is the most important part of the mixer. This paper applies the integrity of signal to analyze the characteristics of Schottky diode. Based on analyzing the discontinuity of the pad and the parasitic capacity, a circuit based module is put forward. Then the model of Schottky diode is set up according to the designed physical parameters，including size，the dielectric constant of the material of the Schottky diode etc. The rationality of the equivalent circuit is proved by comparing the S parameter generated by High Frequency Structure Simulator(HFSS) and the simulation result of a circuit based model generated by Ansoft-designer. The model can be applied to the circuit-level simulation of terahertz mixer.

Abstract:A Charge Coupled Device(CCD) camera controller based on Algorithmic State Machine (ASM) in FPGA is proposed in order to solve the problems of poor reliability, high power and hardware consumption, poor reprogram ability, etc. for space Time Delay and Integration Charge Coupled Device(TDICCD) camera controller based on DSP processor. The proposed controller takes FPGA instead of DSP, and the controller program is written in VHDL language. The whole controlling program is implemented by ASM. The self-developed ground test equipment is employed to test the proposed camera controller. The experimental results indicate that the proposed camera controller can work stably and normally; and the image captured by CCD is very clear without being overlapped. It consumes less FPGA resource for the whole controlling program, and the utilization of LUTs and Block RAMs are 38% and 20%, respectively, which satisfies the application requirement of space camera.

Abstract:In order to solve problems of long time charging, low efficiency, overcharging and undercharging caused by the conventional battery charging methods, a new power supply is designed. The new power supply chooses the full bridge converter as the main circuit, taking ADuC814 microcontroller and SG3525 as the master control chips, and adding into the intelligent management. Prototype test waveform and experimental results demonstrate that this intelligent power supply not only has high stability, but also is time-saving; and its output voltage ripple is below 100 mV, and the efficiency is above 85%, which can achieve good practical value.