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2017 Vol. 37, No. 2

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Recent Advances in the Sparse Fourier Transform
ZHONG Shun-an, WANG Xiong, WANG Wei-jiang, LIU Jian-yan
2017, 37(2): 111-118. doi:10.15918/j.tbit1001-0645.2017.02.001
Abstract(2189) PDF(3688)
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Sparse Fourier transform (SFT) is a novel algorithm for discreting Fourier transform (DFT) on sparse signals, and is more efficient than the traditional fast Fourier transform (FFT). Reviewing the theoretical framework, restrictions and the key technical problems such as random spectrum permutation, window filtering and subsampled FFT, our different kinds of reconstruction means:hash mapping, aliasing-based search, phase decoding, binary search were introduced based on the latest theoretical achievements of the algorithms. Finally, some applications based on SFT were introduced, and its outlooks were presented.
Numerical Investigation on Unsteady Aerodynamic Characteristics of Variable-Span Morphing Wing
HAN Han, YU Yong, HU Jun
2017, 37(2): 119-125. doi:10.15918/j.tbit1001-0645.2017.02.002
Abstract(1024) PDF(816)
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In order to explore the unsteady aerodynamic characteristics and the mechanism of morphing wing during span-varying process, numerical simulations were conducted for a model of ONERA M6 wing based on dynamic mesh technology, and its unsteady aerodynamic characteristics were studied. The results show that, as the hysteresis loops, the unsteady aerodynamic characteristics curves of morphing wing during shape morphing are surrounding the corresponding quasi-steady curves; that morphing period, angle-attack and stream Mach number have some influences on the loops. But compared with the corresponding quasi-steady, the unsteady aerodynamic characteristics caused by variable span are not significant; under certain numerical condition, the maximum of unsteady lift coefficient deviation from the corresponding quasi-steady is less than 2%. The main reason of the above unsteady aerodynamic characteristics is flow field structure hysteresis. Meanwhile, the unsteady aerodynamic characteristics of variable-span morphing wing are not significant due to the weak flow field structure hysteresis.
Microcosmic Structure and Mechanics Performance of EPDM Rubber in Hot-Oxygen Aging
YANG Xiao-hong, XU Jin-sheng, ZHOU Chang-sheng, LI Hong-wen, DU Hong-ying
2017, 37(2): 126-130. doi:10.15918/j.tbit1001-0645.2017.02.003
Abstract(1287) PDF(2259)
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Aiming at the EPDM used usually as the ablation resistant material on the inner surface of the rocket case, the influence on EPDM rubber aging performance of vulcanization system, such as sulfur vulcanization, sulfocompound vulcanization and peroxide vulcanization, was studied in this paper. And the surface topography, relative content of surface components and mechanical properties such as compression permanent deformation and compressive stress relaxation of peroxide vulcanization EPDM before and after the hot oxygen aging were studied with SEM micro analysis and macroscopic mechanics experiment. The results show that, peroxide vulcanization system can make the C-C crosslinked bond which have more stable performance generated inside the EPDM rubber, and the heat-resisting performance is better than the other two. The pyrolysis of EPDM rubber is one-step reaction, the weight loss of each temperature stage, the total weight loss of whole temperature range and the maximum thermal decomposition temperature show no obvious difference between the nonaging and aging samples. Through the surface components analysis, the plasticizer (dibutyl sebacate) migration is found on the surface of aging samples, but there is no obvious volatility. For peroxide vulcanization EPDM rubber, the performance of compression permanent deformation retention rate, compression stress relaxation and tensile strength have a certain degradation, and the higher aging temperature, the greater degree of change.
Application of Krylov Implicit Integration Factor Method in Numerical Simulation of Flame Acceleration
WANG Cheng, BI Yong
2017, 37(2): 131-134. doi:10.15918/j.tbit1001-0645.2017.02.004
Abstract(1032) PDF(607)
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In order to solve the problem in direct numerical simulation based on Navier-Stokes equations to describe flame acceleration and deflagration to detonation transition of combustible gas, a Krylov implicit integration factor (IIF) method was proposed to overcome the difficulty due to the different time scale caused by the non-stiff advection-diffusion terms and stiff reaction terms in Navier-Stokes equations. Explicit scheme was used to discretize the non-stiff terms and implicit scheme to discretize the stiff reaction terms. The equations with implicit scheme make large time step size computations possible. And the large sparse matrix is projected to the Krylov subspace, and the dimension of the Krylov subspace is much smaller than the dimension of the large sparse matrix at lower computational cost. The results of numerical simulation are identical with experimental results. The results show that IIF method could apply in the simulation for NS equations well.
Directional Fracture Blasting in Open-off Cut of Fully-Mechanized Caving Mining Face During Primary Mining
ZHANG Sheng-li, ZHANG Chang-suo, WANG Yin-tao, WANG Chen-long
2017, 37(2): 135-140. doi:10.15918/j.tbit1001-0645.2017.02.005
Abstract(1493) PDF(738)
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In order to solve the gas overrun in the upper corner of fully mechanized caving face during primary mining, a long-hole blasting roof caving method was proposed in the open-off cut to fill the goaf for the effective reduction of ventilation section of working face, so as to improve the ventilation condition and gas emission. Due to the limitation of open-off cut's bolting structures, the blasthole spacing was generally greater than the pre-splitting blasting spacing determined by the experienced formulas, and this would result in poor consequences in the pre-splitting blasting. In order to select a suitable method to increase the balsthole spacing in the field, several charge methods were simulated with ANSYS/LS-DYNA, including the decoupling charge, V-shaped notch and split-tube charge methods. The results show that, directional fracture blasting with split-tube charge has obvious advantages in increasing blasthole spacing and protection of rock wall, and the optimal width of split-tube can be determined by numerical simulation. Finally, through the application of the long-hole blasting roof caving in the working face K8205 of Guo Yang company, the comparison of coal pillar stress before and after the blasting as well as one-knife cut shows that the method has good effect on the blasting.
A Method to Predict JWL Equation of State Parameters for DNAN Based Melt-Cast Explosives
CAO Tong-tang, ZHOU Lin, ZHANG Xiang-rong, JIANG Zhen-ming
2017, 37(2): 141-145. doi:10.15918/j.tbit1001-0645.2017.02.006
Abstract(1100) PDF(1246)
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The equation of status (EOS) should be used to predict power capability of explosives during the design of DNAN based melt-cast explosives to meet the requirements of warhead damage power. A method based on BKW program was used to predict JWL EOS parameters of explosives. The P-V curves of JWL EOS for typical explosives were achieved using the method. Comparisons of the calculated P-V curves with the cylinder test experimental P-V curves for typical explosives indicate that two curves agree very well at high and low pressure region, error less than 10% can be seen at medium pressure region. Acceleration process of copper plate was simulated with DNAN based melt-cast explosive JWL EOS parameters. The calculated velocity of central point in copper plate free surface agrees well with the experimental velocity of central point in copper plate free surface, the maximum error is less than 7%. Research results indicate that the method can be used to quickly predict the JWL EOS parameters and power capability of explosives during the period of designing DNAN based melt-cast explosive formulations.
Time Domain Method in Large Freight Vehicle Ride Comfort Analysis
RONG Ji-li, ZHENG Yu-long, LIU Hu, HE Li, WANG Xi
2017, 37(2): 146-150,156. doi:10.15918/j.tbit1001-0645.2017.02.007
Abstract(1089) PDF(450)
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In order to solve the problem that vibration of vehicle-mount facility is too large to keep its performance in the running large freight vehicle, a facility-vehicle-road coupled model with 19 degrees of freedom was built based on Lagrange's principle. A time domain incentive model of random road was constructed by using a white noise-based model. And based on above two models, vibration of the facility on the vehicle was studied in different situations by time domain analysis method. And particle swarm optimization (PSO) was used to optimize related parameters. Results indicate that improving road level, choosing an appropriate speed, appropriately reducing the stiffness and damping of the facility's suspension can reduce the vibration of the facility and improve the large freight vehicle ride comfort. The research results provide a certain reference value to engineering problems.
Numerical Simulation of Rigid Body and Fluid Coupling Using Immersed Boundary Method
WANG Wen-quan, ZHANG Guo-wei, YAN Yan
2017, 37(2): 151-156. doi:10.15918/j.tbit1001-0645.2017.02.008
Abstract(1366) PDF(2738)
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To avoid the deviation produced in the traditional body-fitted numerical methods and the complex interpolation for sliding mesh on the interface between stator and rotor, a new numerical simulation method was presented for studying on free rotation of rigid body about a fixed axis under fluid force. A mathematical model was established to describe the interaction between immersed rigid body and fluid based on the projection step method. In this paper, the moment source was not pre-calculated, but determined implicitly in such a way that velocity at the immersed boundary interpolated from the corrected velocity field accurately satisfied the no slip boundary conditions, also, the displacement and velocity of rigid body was updated according to the theorem of moment of momentum. The Quick upwind scheme and the second central scheme were applied to solve convection and diffusion terms respectively. The second explicit Adams-Bashforth method was used to the time discretization. Taking the flow over one circular cylinder with Reynolds number 300 as the basic numerical example, the present immersed boundary method(IBM) was validated.
Dynamic Modeling of Parafoil Based on CFD Simulation and Least Squares
SUN Qing-lin, LIANG Wei, TAO Jin, LUO Shu-zhen, CHEN Zeng-qiang, HE Ying-ping
2017, 37(2): 157-162,167. doi:10.15918/j.tbit1001-0645.2017.02.009
Abstract(1153) PDF(896)
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The aerodynamic calculation of flap deflection is a key program of parafoil modeling. In order to improve the precision of parafoil dynamic model, an aerodynamic model of flap deflection was proposed based on a method combining CFD numerical simulation with least squares identification. Numerical simulation based on dynamic mesh was used to observe the change of parafoil shape and posture, which was responsible for obtaining aerodynamic data. Least squares used to identify the parameters of model, which was responsible for aerodynamic calculation of flap deflection. Research results show that, the aerodynamic model of flap deflection can better describe the aerodynamic rules of parafoil and the simulation results of parafoil dynamic model are close to airdrop test data, which verifies the effectiveness of the modeling method in this paper and provides a new idea for precise modeling of parafoil.
Survey on Attack and Defense Technologies of Android Software Security
XU Jun-feng, WU Shi-Zhong, ZHANG Li
2017, 37(2): 163-167. doi:10.15918/j.tbit1001-0645.2017.02.010
Abstract(1434) PDF(2402)
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The mobile Internet is impacting on our life style and ideology with overwhelming force. Android occupies the dominant position of the mobile internet intelligent operating system, and its platform has a high degree of openness and widespread popularity resulting in serious security challenges. Aiming at the technical point of view, the Android software security penetration attacks and reinforced protection technologies were discussed, and the Android software technology and typical attack means were introduced. The key technologies were classified, according to two aspects that act on strengthening the detection and protection system of Android software. Finally, the future development direction was forecasted in the field of Android software security.
A Homology Detection Technology Based on Improved Edit Distance and LCS
LIU Yun-long
2017, 37(2): 168-174. doi:10.15918/j.tbit1001-0645.2017.02.011
Abstract(1079) PDF(668)
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Because some problems existed in traditional token-based algorithm for homology detection in structured information location, module identification, module extraction and high precision homology measure for code variants, a structured recognition homology detection technology was proposed based on an improved edit distance algorithm and improved longest common sequence (LCS) algorithm. In the edit distance calculation, the exchange operator was introduced to improve the measurement accuracy of internal homology modules. In the LCS algorithm, a minimum size monitoring mechanism and line maximum dynamic correlation measure were introduced for similar modules, which offered the ability of code structure boundary division, module line association and structured information extraction. Experiments show that the structure information based algorithm is effective and stable for code homology detection, and the results of random sampling detection show its better performances in precision, recall rate andFvalues. Experiments show that the algorithm utilizing structure information for code homology detection is effective and stable, and the results of random sampling detection have better performances in precision, recall rate andFvalues.
Research on UWB Synchronization Technology and its Implementation in FPGA
NIE Qing, FANG Ning, XU Zhan, GAO Fei, YANG Bo
2017, 37(2): 175-179. doi:10.15918/j.tbit1001-0645.2017.02.012
Abstract(975) PDF(569)
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In order to simplify the complexity and reduce clock of field programmable gate array(FPGA), an improved multi-channel parallel synchronization scheme was proposed based on traditional sliding window correlation, combining the 1 bit quantification and multipath energy accumulation algorithm. In this paper, a method was designed to implement the FPGA, the influence of 1 bit quantification on system performance was analyzed and the quantitative results of SNR loss was provided. The simulation results show that the 1 bit quantification can bring 2 dB SNR loss in Gaussian and Rayleigh channel. The best threshold range can be got through the simulation of false alarm probability and detection probability in Gaussian and Rayleigh channel.
Wave Variables Four-Channel Bilateral Control Method Based on Master Side Force Buffer
GAO Xin, ZHAO Qi-fei, WU Li-kai, SUN Han-xu, JIA Qing-xuan, YANG Yu-kun
2017, 37(2): 180-184,211. doi:10.15918/j.tbit1001-0645.2017.02.013
Abstract(1033) PDF(515)
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The synchronization performance will directly affect the transparency and tracking of the teleoperation control system. A wave variable four-channel bilateral control method based on the master side force buffer was proposed in this paper. Firstly, a quantitative measure function for the synchronization performance with constant time delay was presented. Secondly, in the wave variables four channel bilateral control structure, a master and slave controller with heterogeneous form was designed, which was added with a force buffer unit and a compensation unit to realize the master slave synchronization control, and the effect made by the wave transformation method's leading action on the master controller was eliminated. On this basis, the stability of the proposed method was analyzed by the multi-loop feedback structure stability analysis method, and the constraint condition of the system stability was obtained. Finally, Numerical simulations and experiments were performed to study the efficiency of the proposed method.
Detecting the Impact of Trace Water on Solidifying Point and Pour Point of Insulating Oil Based on the Infrared Spectrum
CHEN Bin, WU Hong-yang, LIU Ge
2017, 37(2): 185-190,195. doi:10.15918/j.tbit1001-0645.2017.02.014
Abstract(853) PDF(592)
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It is necessary to investigate the affecting mechanism between the trace water content and solidifying point of insulating oil and to take effective measures to monitor the insulating oil operating status, because the trace water impacts significantly on the solidifying point, pour point of insulating oil in some extent. Firstly,a series of oil samples were made up with different water content, and the experimental values of solidifying point and pour point of oil samples were tested. Then the mid-infrared spectral pictures of the oil samples were obtained, which can acquire the absorbance values of paraffin wax (at the wave number of 722 cm-1), water (at the wave number of 1640,3 400,3 450,3 615 cm-1). Finally, absorbance values of water and paraffin wax in characteristic wave number, the experimental data of solidifying point and pour point were combined to calculate the Pearson correlation coefficient and create linear correlation formula between these data and the water content. And according to the measured values of pouring point and solidifying point and infrared spectral absorbing values of oil samples at the wave number of 722,1 640,3 400,3 450,3 615 cm-1, the multiple linear regression model was constructed. Analysis results show the goodness of fitting model is 0.987 3, 0.993 6 respectively, the error between calculated values and measured values of pouring point and solidifying point is from 0.033% to 0.350%. According to the model, the laws of trace water impact on the solidifying point, pour point of insulating oil were discovered. It is shown that solidifying point pour point values of the oil tend to increase slightly with the increase of moisture content in the oil/water dispersion system, the effect of moisture on absorbance value of paraffin wax is obvious; and the foundation about on-line monitoring of trace water in oil is established.
Influence of External Electric Field of Electret on Polarization Properties of Cyclosporine A Patch
GUO Xin, WANG Tao, SHI Yan, HUANG Ping, LIANG Yuan-yuan, WANG Chun-xiao, JIANG Jian
2017, 37(2): 191-195. doi:10.15918/j.tbit1001-0645.2017.02.015
Abstract(809) PDF(717)
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In this paper, the cyclosporine A and ethyl oleate were selected as model drug and enhancer respectively. A series of patches with different content of drug and/or enhancers were prepared. The positive electrets with different surface potentials were applied to the patches to study the relationships between polarization rules and patch parameters. The results show that the external electric field produced by electret can result in the polarization of the cyclosporine A patches. The polarization degree of the patch is proportional to the surface potential of the electret, but inversely proportional to the content of the drug as well as enhancer. The polarization degree caused by electret for different patches is in the following order:enhancer patches > drug patches > enhancer containing drug patches. Therefore, the external electric field of the electret can cause the polarization of the drug and enhancer which is favorable for the controllable transport and release of the drug.
Modeling and Analyzing the Electrical Properties of Low Resistivity Silicon Through Silicon Via (TSV) in 2.5D Integrated Circuit
WANG Shi-wei, LIU Bin, LU Wei, YAN Yang-yang, CHEN Shu-fen
2017, 37(2): 196-200,206. doi:10.15918/j.tbit1001-0645.2017.02.016
Abstract(1945) PDF(1983)
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2.5D integration technology can enable the heterogeneous integration of several chips which fabricated by different technology or substrate. The low resistivity silicon through silicon via (LRS TSV) can take the place of copper TSV as its good conductivity, as well as the merits of simple process and low costs. The electromagnetic (EM) simulation of LRS TSV was performed. And the simulation results show that its return loss can be -24.7 dB and insertion loss can be -0.52 dB at 1 GHz which meet the requirement of transmission line. The electrical model of LRS TSV was proposed. Compared with electrical model, the EM results show good agreement, and it can be applied in 0.1~10 GHz tape width. In the end, the simulation results of time domain transmission (TDT), time domain reflection (TDR) and eye diagram show that the resistance of LRS TSV has more considerable impacts on voltage drop than the parasitic capacitance of LRS TSV.
Thermal-Mechanical Analysis of Low Resistivity Silicon Through Silicon Via (TSV) During High Temperature Process
WANG Shi-wei, YAN Yang-yang, CHENG Zhi-qiang, CHEN Shu-fen
2017, 37(2): 201-206. doi:10.15918/j.tbit1001-0645.2017.02.017
Abstract(1283) PDF(1598)
Abstract:
This paper focuses on thermal mechanical analysis of low resistivity silicon through silicon via (LRS-TSV), since there are few researches on it. Firstly, the process flow for LRS-TSV based interposer was introduced. Then based on experimental dimension of LRS-TSV, protrusion height and thermal stress of LRS-TSV were simulated under 350℃. The simulation result shows that, compared with copper based TSV, protrusion area of LRS-TSV are mainly upon polymer insulation. To decrease protrusion height and thermal stress of LRS-TSV, factors such as process temperature, thickness of top SiO2layer, LRS-TSV diameter, height, space and thickness of insulation were investigated respectively. From results, it shows that decreasing the thickness and height of insulation, increasing thickness of top SiO2layer are effective solutions to reduce the protrusion height and release thermal stress.
Preparation ofβ-Cyclodextrin Encapsulated Squaramide Based Chemosensor for the Selective Detection of I-and NO2-
SHI Rui, CHEN Shu-sen, JI Jia-wen, WU Xiao-xue, LI Li-jie, SHU Qing-hai
2017, 37(2): 207-211. doi:10.15918/j.tbit1001-0645.2017.02.018
Abstract(1398) PDF(585)
Abstract:
Aβ-cyclodextrin encapsulated squaramide derivative SA (cyclobuta[b] quinoxaline-1,2 (3H, 8H)-dione) were synthesized for the selective sensing of I-and NO2-in aqueous solution in competitive fashion. With I-and NO2-, the encapsulated probe shows a highly characteristic UV-Vis absorbance enhancement at centered 262 and 365 nm, respectively over other tested ions. Furthermore, the quantitative analysis of the both target anions was successfully achieved by the absorption titration, making the fast and trace amount detection of I-and NO2-possible by probe.
Structural Stability of the Solid Hydrogen Structures by First Principles Under 60~160 GPa
YIN Yan-hua, SUN Mei, PANG Zhi-kang
2017, 37(2): 212-215. doi:10.15918/j.tbit1001-0645.2017.02.019
Abstract(948) PDF(1171)
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To research the structural stability of the solid hydrogen structures, the thermodynamic and dynamic properties of the solid hydrogen structures of Ⅱ phase P63/m, P21/c, P63/mmc, Pca21and Ⅲ phase C2/c were calculated by first-principles calculations under 60~160 GPa. The results suggest that that only P63/m, C2/c and Pca21are competitive structures. The Pca21, P63/m, and C2/c structures can stably exist in the pressure range 60~78, 78~90 GPa, and 116~160 GPa, respectively.
Generalized Gradient Representations of Appell Equations and Its Stability Analysis
CUI Jin-chao, LIAO Cui-cui, WANG Yong
2017, 37(2): 216-220. doi:10.15918/j.tbit1001-0645.2017.02.020
Abstract(1130) PDF(625)
Abstract:
Appell equation is a kind of important equations in analytic mechanics, which is not only suitable for holonomic systems but also applicable to nonholonomic systems. In order to study the stability of solutions of Appell equations, the gradient systems were extended to generalize gradient systems which contain the variable of time. Two kinds of generalized gradient systems were put forward and the characteristics of the systems were studied. The conditions under which Appell equations could be considered as one of two generalized gradient systems were obtained. Then, the stability of solutions of Appell equations were studied based on the characteristics of generalized gradient systems. Some application results show the feasibility.

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