Abstract:

A novel terahertz(THz) metasurface with multi-frequency narrow band resonance effect is constructed based on Single-Walled Carbon Nanotubes(SWCNTs) thin films. The influence of structural parameters of periodic microstructure unit on the resonance characteristics of the metasurface is analyzed. Furthermore, the resonance coupling mechanism of the device is studied, and the simulation and theoretical calculations have good consistency. In addition, the refractive index sensing characteristics of this THz metasurface device are analyzed by covering a dielectric layer with different refractive indexes on the metasurface. The function fitting results show that the metasurface device can achieve high sensitivity refractive index sensing up to 64 GHz/RIU.

Abstract:

A new type of transmissive terahertz polarization conversion device is proposed based on the metamaterial structure of the combination of square open ring and metal rod. Specifically, the influence of different combinations of basic structural elements on the polarization conversion characteristics is first studied. The working bandwidth of the polarization conversion function is improved by optimizing the relevant parameters of the structural units. Finally, the efficient X-Y cross-polarization conversion is realized in the range of 0.45~1.30 THz, which is expected to be used in the research and application of integrated terahertz polarization conversion devices.

Abstract:

Most existing special beams(focused beams, Airy beams, etc.) metasurfaces usually use metallic materials for a single wavefront modulation by changing the dimensions of the cell structure, the angle of rotation, etc. There are fewer researches on metasurfaces for special beams with dynamically tunable wavefronts. Therefore, breaking the barrier of traditional structures, special beam metasurfaces which utilize Fermi energy levels of graphene to dynamically modulate the wavefront are constructed. Stronger freedom in dynamically modulating the wavefront can be realized in order to achieve more and more complex phase requirements. Focusing metasurfaces with tunable wavefront and tunable Airy beam metasurfaces are designed, different phase distributions are obtained by tuning the Fermi energy levels of graphene. Utilizing the dynamic wavefront, the spatial position of the focal point, the switching of the focusing switch with the number of focal points, and the parameters affecting the Airy beam can be regulated.The proposed dynamic tunable wavefront special beam metasurfaces are helpful for terahertz applications in high-resolution imaging, focus-tunable planar lenses, optical micromanipulation, laser micromachining, and optical bullet molding.

Abstract:

A novel one-dimensional graphene-Photonic Crystal(PhC) composite resonant structure is designed, and the strong coupling effect between the terahertz Tamm Plasmon Polaritons(TPP) and Cavity Modes(CM) supported by the Transmission Matrix Method(TMM) is theoretically studied. It is shown that the Rabi splitting energy employed to characterize the coupling strength increases with the decrease of the number of PhC periods. In addition, when changing the thickness of the spacer layer and the cavity, as well as the Fermi level of graphene, the Rabi splitting energy is also affected. Finally, the coupling mode can also be actively adjusted by changing the angle of incidence. When the angle of incidence is between 0° and 60°, the characteristics of the coupling mode are independent of polarization. This work provides a new idea for the study of strong coupling effect.

Abstract:

Terahertz(THz) wave has great development potential in biomedical science due to its nonionizing, labelless and real-time characteristics. To distinguish biological tissues with similar permittivity, a metamaterial with Fano resonance is designed and fabricated for THz reflection imaging. The simulation and experimental results show that the reflection sensitivity of the metamaterial is 132 GHz/RIU at 0.82 THz. The metamaterial not only enhances the contrast of imaging resolution plate, but also improves the contrast between the muscle and the fat tissues by approximately 7.5%, therefore, it can improve the contrast of biological tissue slice images. This work has established an experimental and theoretical foundation for future terahertz applications in clinical tissue samples.

Abstract:

Three artificial sweeteners, sucralose, erythritol and xylitol, are qualitatively and quantitatively studied based on Terahertz time-domain spectroscopy combined with machine learning algorithms and optimization algorithms.The results show that the Sparrow Search Algorithm-Support Vector Machines/Support Vector Regression(SSA-SVM/SVR) model is optimal for qualitative and quantitative analysis of the mixture. The accuracy of classification prediction is up to 95.56%, and the optimal regression coefficient for quantitative regression prediction is 0.999 8, so that a high-precision classification and quantitative analysis of three sweetener-flour mixtures is achieved. This provides an effective and reliable method for the rapid detection of artificial sweeteners.

Abstract:

Radar waveform design is facing severe challenges with the development of electronic reconnaissance technology such as intra-pulse feature recognition and signal deinterleaving. Amplitude modulation can improve the anti-identification ability of the waveform by increasing the signal complexity in time domain, which is a newly developing modulation method. A novel radar waveform with joint amplitude-phase coding modulation is proposed in this paper. It improves the complexity of radar waveform through Amplitude-Phase Joint Modulation(APJM), which is promising in anti-reconnaissance. In addition, regarding the processing of this signal, an echo signal processing method combining matched filtering and Compressed Sensing(CS) is proposed, which uses the sparse sampling characteristics of amplitude. The proposed signal processing method effectively improves the detection probability under the condition of a low Signal-to-Noise Ratio(SNR). In the end, simulation results show the effectiveness of the proposed waveform design and processing method of the joint amplitude-phase modulation radar waveform.

Abstract:

As an important part of space information network, low-orbit satellite Internet of Things (IoT) has the problem of high complexity of interference calculation in interference analysis and coordination with other communication systems due to its proliferation of constellation size, dynamic satellite platform and large number of terminals. In addition, the distribution of IoT terminals in practice is highly correlated with geography and population, but due to the large coverage area of a single satellite, it will face multiple densities and deployments of terminals, and the use of static traversal calculations will bring an explosion of computing power. Starting from the mechanism of co-channel interference generation, the regionalized transmit field strength is used as the core of modeling the uplink aggregate interference of dense IoT terminals, and the Poisson Point Process(PPP) distribution model is introduced to equivalently model the ground terminals, so that the regionalized uplink aggregate interference is only related to the distribution parameters and transmit parameters, but not to the exact location and number of terminals. The simulation results show that the proposed method has less error compared with traditional link analysis, and has better fitting performance for different number of terminals. It can effectively reduce the computational complexity in long-time analysis, and can be used for interference analysis and calculation with high efficiency.

Abstract:

The existing transient magnetic field measurement in high power laser devices does not consider the shielding and signal reduction. A sensor is designed and developed for transient magnetic field measurement in high power laser devices according to the frequency range and characteristics of transient magnetic field. The brass is taken as the shielding material, and the leather is taken as the insulation material. The sensor is employed to measure the transient magnetic field, and the magnetic field response is up to 500 MHz. This work provides data support for the research on electromagnetic interference and electromagnetic compatibility for high power laser device.

Abstract:

Transient response analysis of Transmission Line(TL) systems with frequency-dependent load is an important topic in the field of electromagnetic compatibility, especially for the situation where the frequency-dependent network is more complicated or the internal structure is not clear, the corresponding analysis of its transient response is more difficult. In this paper, firstly, the corresponding sampling values are obtained by measuring or calculating the admittances of the frequency-dependent loads at the sampling frequencies, and the equivalence of the admittances is performed by adopting the rational function approximation; then, the Piecewise Linear Recursive Convolution(PLRC) expression of the voltage at the connection point between the TL and frequency-dependent loads is obtained by bringing the poles and residues solved by Matrix Pencil Method(MPM) into the PLRC technique; finally, the transient response analysis of the TL system with frequency-dependent loads is obtained by combining the MPM, PLRC and TL equation, and the performance of the proposed method is verified by two numerical examples. The results illustrate that the proposed method has obvious advantages in calculation accuracy.

Abstract:

Stochastic Testing(ST) method is an uncertainty quantification method. The existing ST methods are still unable to handle situations with arbitrarily distributed variables. This paper uses the Gram-Schmidt orthogonalization algorithm to construct a chaotic polynomial basis for arbitrarily distributed random variables to extend ST method. The extended ST method is applied to the field line coupling analysis of transmission lines. In the calculation of field line coupling, due to the uncertainty of the radiation field, there is uncertainty in the polarization angle, azimuth angle, and elevation angle of the incident wave, resulting in uncertainty in the response of the transmission line, leading to the problem of random field line coupling. For the case where the input parameters follow an arbitrary distribution, ST method is applied to quantify the uncertainty of the coupling response of the transmission line field. Performing polynomial chaos expansion on the output response of the model and solving the expansion coefficients, statistical information of the model response is obtained. Combining the field line coupling examples of single random variable and multi-random variable, the statistical information of transmission line voltage response is obtained. Compared with Monte Carlo Simulation(MCS) method, the correctness and efficiency of the ST method are verified.

Abstract:

Hilbert-Huang Transform(HHT) is an efficient adaptive analysis method in nonlinear and nonstationary signal analysis, processing and feature extraction, which is widely used in engineering field. In this paper, Empirical Mode Decomposition(EMD) and Variational Mode Decomposition(VMD) are employed to compare and analyze the underwater acoustic signals of offshore motorboats. It is found that the energy of underwater acoustic signal is mainly concentrated in the low frequency band, and its amplitude is relatively large compared with that in the high frequency band. When analyzing this kind of signal, mode mixing is produced by EMD method, therefore using EMD cannot effectively decompose the signal and extract features. Nevertheless, using VMD method can effectively reduce the phenomenon of mode mixing and successfully extract its signal characteristics. The results show that VMD method is more effective in ship underwater acoustic signal processing and feature extraction.

Abstract:

The fully polarized Radar Cross Section(RCS) sequences of two simulated ballistic targets are obtained from microwave anechoic static measurement inversion under typical combat conditions. In view of the nonsmoothness and proposed periodicity characteristics of this time series, it is not effective to estimate precession period directly by spectral analysis. Therefore, wavelet method is employed to reduce noise and enhance the details of the precession passband in the pre-processing process. The full polarization channel fusion process is carried out by Principal Component Analysis(PCA) and polarization invariant method respectively. The experiment results show that the extraction method using polarization information is significantly better than the single polarization channel extraction method, and the error is less than 0.002 Hz in noiseless observation environment.

Abstract:

The attenuation characteristics of Acoustic Emission(AE) signals in liquid and gas pipelines with complex structures are studied. By collecting acoustic emission signals of pipe body under different flow pressures, the amplitude attenuation law is analyzed, and the composition changes of pipe acoustic emission signals are studied by DB8 wavelet packet and Fast Fourier Transform(FFT). Through collecting acoustic emission signals before and after valve, flange, flow meter and other six kinds of pipeline accessories and analyzing attenuation law, it is found that electromagnetic flow meter is the pipeline component that has the greatest influence on the attenuation of acoustic emission signals. Then, the effect of fastening degree of bolt connection on signal amplitude and frequency components is analyzed. The results show that the higher the fastening degree of bolt, the lower the signal attenuation. The relevant research conclusions of this paper have integrated reference value and guiding significance for the sensor layout decision of acoustic emission detection of oil or gas pipelines in engineering.

Abstract:

The reliability of the device is very important in the complex space electromagnetic environment where the circuit is greatly affected by cosmic rays and single particles. Anti-fuse Field Programmable Gate Array(FPGA) is a one-time programmable device with anti-fuse as the basic programming structure. Since the state of anti-fuse FPGA cannot be reversed after programming, it has the advantages of non-volatility, high confidentiality, high reliability, and radiation resistance, which is very suitable for aerospace and other fields. A design scheme of anti-radiation wave control unit based on domestic anti-fuse FPGA is presented to solve the problem of radar array in space electromagnetic environment. The domestic anti-fuse FPGA chip is taken as the core in the proposed scheme. The working principle and realization block diagram of the system circuit are given, and relevant experiments are conducted. The experimental results show that the transmission delay of RS422 is less than the symbol period under the baud rate of 5 MHz, and the phase distribution time of the 144-unit phase-shifting component is less than 500 μs, which meets the design requirements.

Abstract:

Micro-Electro-Mechanical System(MEMS) inertial switch has broad application prospects in the field of fuze, but there are few low-g MEMS inertial switches that can be used in the working environment of fuze. A design of MEMS inertial switch with low closing threshold is proposed for the fuse of ammunition with low launch overload, to meet the functional requirements of the fuze to identify the low-g value impact signal, and to realize the function of stable connecting the fuze power supply. At the same time, the designed MEMS inertial switch has the ability to resist high overload in the fuze's working environment and improve the reliability of the fuze. The design requirements are put forward according to the characteristics of the trigger signal and the working environment of the fuze. The oscillation model of the inertial switch is theoretically analyzed. The influence law of the structural size of the inertial switch on the switch performance is clarified. The overall design scheme of the switch is given, and the design results are simulated and verified by ANSYS finite element analysis software. The simulation results show that the designed inertial switch can monitor the impact signal with amplitude of 20g and pulse width of 1 ms, the response time is less than 1 ms, the electrode contact time is longer than 30 μs and anti-overload performance reaches 12 000g, meeting the proposed performance index requirements.

Abstract:

Effective choice of the solution is essential to achieve a real-time, bi-directional(full- duplex) communication of the smart grid. The Power Line Carrier(PLC) technology provides a low-cost solution, which suits China's own national conditions. In this paper, the advantages of OFDM PLC modulation technology are introduced. A PLC module of system model is established through the analysis of the input impedance under the low-voltage power line channel. The high-speed PLC module based on low-voltage Power Line is also designed according to the studies of power line channel. The results show that the design of the PLC module has featured high receiving sensitivity and anti-noise ability.

Abstract:

With the development of Internet applications, users’ demand for bandwidth is soaring sharply. Meanwhile，along with the development of broadband access technology, the endpoint can also adopt multiple network accesses. But due to one-way communication of traditional Transmission Control Protocol(TCP)，the waste of resources will exist. To this end，IETF has specifically proposed Multi-Path TCP(MPTCP) to implement TCP multiplexing，thereby enhancing the efficiency and robustness. This paper gives a review of the IETF’s research on MPTCP，including MPTCP architecture, routing and congestion control, aiming to provide a reference for deeply studying.

Abstract:

Traditional methods and instruments are not able to measure the true Root Mean Square(RMS) of distortion sine wave or non-sine signal accurately. This article introduces a method to measure the true RMS of any high frequency signal by using the true RMS measurement IC，AD536A，designed by AD corporation. The paper analyses the difference between the RMS measured by the average measure method and the true RMS in theory. It explains the disadvantages of current RMS measure method，and presents the design of true RMS measure circuit. The experiment results prove that the proposed method and circuit can measure the true RMS of any high frequency signal accurately.

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 requirements for micro stress measurement of strain gauge are high precision，high linearity，high stability and high gain. One kind of differential amplifier circuit with excellent performance was designed. Some skillful techniques were adopted to avoid common voltage in the circuit and to reduce the temperature drift. The gain linearity is about 0.01%，and its Common-Mode Rejection Ratio(CMRR) is about 129 dB under work conditions.

Abstract:

Terahertz(THz) optoelectronics has promoted the development of the THz generation, transparent control, and detection methods，and hastened many devices in the past decades. Especially, THz metamaterials and metasurfaces will exhibit extraordinary electromagnetic response when the subwavelength scale metal structure is excited by the THz illumination. Therefore, they have been applied to the devices such as wave beam shaper, waveguide, and modulator etc. The THz metamaterials and metasurfaces also show the potential applications in the research fields such as sensors, communications, and radars. In this paper, the works about the spectrum and wavefront modulation with THz metadevices carried out in our group are summarized. The basic theory and corresponding experiment results for different devices are introduced. It is expected these works can pave the avenue of the application of the THz metadevices.

Abstract:

According to the requirements of safe, simple and nondestructive radiation effect investigation of semiconductor devices, the method of laser simulation was proposed and greatly promoted. Compared with large-scale facilities, laser simulation has various unique advantages. It helps understand the ionization radiation effect in depth and is an effective low-cost, table-top supplement for the hardness assurance. Its research shows great significance for radiation effect study in both theory and practice. In this paper, the basic principles of the interactions of γ and laser with semiconductor devices are firstly presented. Then the physical basics and characteristics of laser simulation are given, with the research progress review followed. The existing problems of current research are deeply discussed providing with feasible research approaches. In the end, necessary research contents in the future are proposed.

Abstract:

The background requirements of the fuze antenna in terahertz spectrum as well as its advantages and disadvantages are introduced. The working principles and application characteristics of dielectric lens antenna in terahertz frequency are analyzed in order to implement the terahertz fuze antenna. The longitudinal size of H plane horn antenna can be reduced effectively by using fuze antenna formed by an H plane horn with dielectric lens antenna. The terahertz fuze antenna with different beam angles is achieved by focal technology of lens. The feasibility of the technology solution is verified through simulation.

Abstract:

Radio Frequency IDentification(RFID) series Radio Frequency(RF) card has been applied widely because of its stability，reliability and easy operation features. Aiming at multiple protocols，such as ISO14443 protocol，ISO15693 protocol and Tag-it protocol，this study proposed a new type of circuit design based on Advanced RISC Machine(ARM) for the RFID series RF card reader. The data stream encryption was implemented by using peripheral device in the operation. The system composition，working principle and work flow were introduced. Then，the detailed circuit design of the RF network and encryption hardware were presented，and the test and analysis for the design were performed. The results showed that the circuit could accurately read, write and encrypt various types of card within effective range.

Abstract:

Ultra-wideband(UWB) communication shows its advantages of fast data transfer(100 Mb/s or above) in a relatively short distance(typically below 10 m) with relatively weak power consumption (energy spectrum below -41.3 dBm/MHz). Integrated with Multiple Input Multiple Output(MIMO) technology, channel capacity could be further enhanced. As a critical link in the ultrawideband communication，UWB antenna needs extra efforts in design optimization to boost the performance of the whole system. UWB antenna is defined as the antenna whose bandwidth exceeds 500 MHz or relative bandwidth greater than 20%. This paper takes the most representative Vivaldi antenna as a show case for multi-objective optimization design with statistical methods. The optimized miniaturized antenna(sized130 mm×100 mm) shows a -10 dB bandwidth of 2.4 GHz. The design method provides guidance in common wideband，multi-parameter antenna design.

Abstract:

This article introduces a new type of high speed，multi-modulated digital modulator with adjustable center frequency and bit rate features. It can realize the Quadrature Phase Shift Keying(QPSK) and 16QAM(Quadrature Amplitude Modulation) with 80 MHz center frequency and 7.936 5 MHz bandwidth. The general-purpose modulation arithmetic based on software radio，symbol mapping and the realization of pulse shaping filter are discussed. The measuring results demonstrate that the modulation scheme meets the requirements of practicability and general utilization.

Abstract:

The implementation of TCP/IP protocol stack on TM320DM642 platform could provide technological support for the application of multimedia embedded systems to networks. Both the function of TM320DM642 chip and the hierarchical structure of LWIP(Light Weight Internet Protocol) were analyzed. Network communications for TM320DM642 systems were implemented by the transplantation of LWIP, not by a solution scheme of NDK(Network Developer’s Kit). Testing examples verified the effectiveness of the LWIP transplanted method.

Abstract:

The design of code tracking loop is a key sector of the realization of noncoherent spectrum spread receiver. In order to realize the code tracking in noncoherent spectrum spread receiver, an energy-normalization digital delay-locked loop was designed, the structure of the loop and the calculating procedure of loop parameters were introduced. The characteristic of noncoherent spectrum spread was analyzed first，and then the key point of the loop design was pointed out. Based on this, the design and realization methods of code loop discriminator, loop filter, early and lag code generator were expatiated. A set of specific loop parameters were introduced as well. Modelsim simulation results and FPGA actual measured data prove the precise code tracking ability of the design.

Abstract:

High-speed data acquisition system is an important component in modern radar signal processing. A design of high-speed data acquisition system based on band-pass sampling was presented and applied to the signal processing of wideband receiver. The Virtex Series FPGA was used as the main platform to control the high-speed ADC08D1000 for completing data acquisition, transmission，storage and signal processing. High-speed First Input First Output(FIFOs) were selected as the storage devices to implement data rate conversion. The system realized the software and hardware design，and test results verified the feasibility of the solution.

Abstract:

The application of CORDIC(COordinate Rotation DIgital Computing) arithmetic in solving transcendental function has become popular in modern engineering. A brief introduction of CORDIC arithmetic was given in this study. Taking the hyperbolic sine and cosine functions as examples, the method of realizing the arithmetic in FPGA was presented and simulated on ISE(Integrated Software Environment) platform. The result showed this arithmetic was of good precision and instantaneity because of using pipeline. This arithmetic has great practical value in some applications. In addition, a curve of the relationship between the iterative number and the error obtained by the Matlab simulation of the arithmetic can help designers planning the number of iterations for practical applications.

Abstract:

The Spatial Light Modulation(SLM) technology has been widely applied to the fields of threshold switch, high speed optical interconnection and optical logic operations, which demands good performance on the real-time and fast optical signal addressing. Compared with Electro-Addressing SLM(EA-SLM), Optically-Addressing SLM(OA-SLM) shows great advantages of fast speed and high resolution by parallel addressing. Nevertheless, how to achieve fast and stable optically addressing is the key point in practice. Based on ZnO thin film as a photoconductive layer, Liquid Crystal OASLM(LC-OASLM) is designed and fabricated; the modulation of the readout light intensity and phase distribution in the two-dimensional space is achieved effectively.

Abstract:

The corresponding solutions are proposed to tackle with the disadvantages of conventional oilfield Geographic Information System(GIS), including inconvenience of Client/Server(C/S) mode operation and maintenance, being unable to perform real-time online Point of Interest(POI) rendering, being incapable of segmentation and location according to regions, etc. An oilfield information query system of Browser/Serve(B/S) framework based on AJAX+JSON+HTML5 is designed and implemented. Experimental results show that the POI real-time rendering and regional segmentation improve on their interactivities, and the experiences of users are enriched, which meets the actual requirements of oilfield development. This work has paved the way for the development of diversified network services.

Abstract:

A detector can achieve quick response when it is much smaller than the wavelength of the source signal in THz wave band at the expense of signal coupling capability．Therefore, an antenna is applied to collect signals in order to enhance the signal coupling capability of the detector．The properties of antenna determine the frequency response band，the sensitivity and other parameters of the detector directly. A planar-integrated antenna is adopted for signal acquisition in the Nb5N6 microbolometer detector, which is fabricated by lithography，lift-off and other processes of micro-fabrication. The Nb5N6 microbolometer is placed in the center of the planar antenna. Aiming for the center frequency of 0.32 THz, a special capacitive coupling design is proposed to improve the signal coupling capability．

Abstract:

The single-channel blind separation of GMSK(Gaussian Minimum Shift Keying) mixing signals is researched. The GMSK mixing signals can not be separated by the Per-Survivor Processing (PSP) algorithm directly, therefore, linear approximation processing of the GMSK signal is considered, which enables GMSK signal to be separated by the PSP algorithm. This algorithm separates the GMSK mixing signals by maximum likelihood estimation in the joint space of the symbol sequential and the channel parameters, reserves the best path and outputs the symbol pairs to get the separated signals. Simulation results show that the bit error rate performance produced by the PSP algorithm on separating the GMSK mixing signals is slightly better than that produced by the particle filtering algorithm; and the complexity of the proposed PSP algorithm is much smaller.

Abstract:

A double gate setting with priority of Doppler velocity and the Extended Kalman Filter(EKF) based Multiple Hypothesis Tracking(MHT) algorithm are proposed in order to realize Multiple Targets Tracking(MTT) in High Frequency(HF) ground-wave radar, and to effectively improve the performance of MTT by using the Doppler measurement. In the EKF based MHT, parameters obtained in the EKF are adopted directly to calculate the probability of each hypothesis. A simulation scene is built, and the EKF based MHT algorithm is compared with the one which assumes that the Doppler measurement is independent from the radius measurement. Simulation results show that the double gate setting helps induce number of clutter, and the EKF-based MHT algorithm is better than the other one under dense environments of HF ground-wave radar with stronger track-catching and false-alarm-filtering ability and higher efficiency.

Abstract:

A new usage of Hough Transform is introduced in this paper.Firstly,the position and scope of the license plate is located and the image that contains the license plate is picked up.Then, a two-stage Hough transform algorithm is applied to the image to cal

Abstract:

A forward secure strong proxy signature scheme is proposed on the basis of the proxy signature schemes and forward secure schemes.The security of the proposed scheme relies on the difficulty of solving discrete logarithm problems and the difficulty of com

Abstract:

Wavelet denoising is an important application of wavelet analysis in engineering.The keys of wavelet denoising,namely how to select threshold and how to utilize the threshold to dispose wavelet coefficients,are introduced.Via the noised simulated signal e

Abstract:

Based on three generally accepted basic hypotheses, the definition of environmental factor and restricting conditions of constant failure mechanism are discussed.The research status and common study methods of environmental factor are reviewed. Finally, a

Abstract:

For completing the scheme of hard target smart fuze, several factors influencing the outputting acceleration of the high-G accelerometer such as target material, impact angle, impact velocity, the fixed position of accelerometer, carry plane etc., are put