Calculation model of military aircraft survivability to a missile

Since missiles are main threat against aircrafts in air war,a model is proposed for calculating the aircraft survivability to a missile.The hit characteristic of aircraft to a missile is analyzed,and then Monte Carlo method is applied to generate missile detonation location according to its distribution rule.In addition,based on the analysis of fragment trajectory and critical components,the intersection point of these two is determined.Then the kill probability of critical component to a fragment can be calculated,and the aircraft survivability to a missile is obtained accordingly.Finally,the feasibility of the proposed method is demonstrated.Simulation results show that this method captures the basic effects of missile detonation locations on aircraft survivability,which may provide an effective reference to aircraft survivability research.

Research on Fault Prediction of Modern Aviation Electronic Equipment Based on Improved Grey Model

The basic principle and method of Grey Model prediction are presented. In view of the defects of general GM(1,1) model, an improved method is proposed. That is using the particle swarm optimization algorithm to obtain the best forecast dimension and using metabolism to make the model parameters adaptively change. Finally, the improved Grey Model is used to predict the fault of high voltage power supply circuit of a certain type of modern air-borne radar. The results which are computed and simulated by Matlab software show that the forecast precision of improved Grey Model is higher than that of original Grey Model.

High-pressure new phases of V–N compounds

The high-pressure diagram of V–N compounds is enriched by proposed seven new stable high-pressure phases.The P-1-VN_4with the armchair N-rich structure may be quenched to ambient conditions.The formed N–N covalent bond plays an important role for the structural stability of N-chain.The charge transfer results in a V–N ionic bond interaction,which further improves the stability of N-chain structure.The P-1-VN_4,P4mnc-VN_8,and Immm-VN_(10)with the outstanding detonation properties have potential application in explosive field.

Effects of Normalized Difference Vegetation Index and Related Wavebands′ Characteristics on Detecting Spatial Heterogeneity Using Variogram-based Analysis

Spatial heterogeneity is widely used in diverse applications, such as recognizing ecological process, guiding ecological restoration, managing land use, etc. Many researches have focused on the inherent scale multiplicity of spatial heterogeneity by using various environmental variables. How these variables affect their corresponding spatial heterogeneities, however, have received little attention. In this paper, we examined the effects of characteristics of normalized difference vegetation index (NDVI) and its related bands variable images, namely red and near infrared (NIR), on their corresponding spatial heterogeneity detection based on variogram models. In a coastal wetland region, two groups of study sites with distinct fractal vegetation cover were tested and analyzed. The results show that: 1) in high fractal vegetation cover (H-FVC) area, NDVI and NIR variables display a similar ability in detecting the spatial heterogeneity caused by vegetation growing status structure; 2) in low fractal vegetation cover (L-FVC) area, the NIR and red variables outperform NDVI in the survey of soil spatial heterogeneity; and 3) generally, NIR variable is ubiquitously applicable for vegetation spatial heterogeneity investigation in different fractal vegetation covers. Moreover, as variable selection for remote sensing applications should fully take the characteristics of variables and the study object into account, the proposed variogram analysis method can make the variable selection objectively and scientifically, especially in studies related to spatial heterogeneity using remotely sensed data.

LPI radar signal detection based on the combination of FFT and segmented autocorrelation plus PAHT

This paper proposes a desirable method to detect different kinds of low probability of intercept (LPI) radar signals, targeted at the main intra-pulse modulation method of LPI radar signals including the signals of linear frequency modulation, phase code, and frequency code. Firstly, it improves the coherent integration of LPI radar signals by adding the periodicity of the ambiguity function. Then, it develops a frequency domain detection method based on fast Fourier transform (FFT) and segmented autocorrelation function to detect signals without features of linear frequency modulation by virtue of the distribution characteristics of noise signals in the frequency domain. Finally, this paper gives a verification of the performance of the method for different signal-to-noise ratios by conducting simulation experiments, and compares the method with existing ones. Additionally, this method is characterized by the straightforward calculation and high real-time performance, which is conducive to better detecting all kinds of LPI radar signals.

A Family of Fifth-order Iterative Methods for Solving Nonlinear Equations

In this paper, we present and analyze a family of fifth-order iterative methods free from second derivative for solving nonlinear equations. It is established that the family of iterative methods has convergence order five. Numerical examples show that the new methods are comparable with the well known existing methods and give better results in many aspects.

Formation and mechanical properties of bulk Cu-Ti-Zr-Ni metallic glasses with high glass forming ability

Bulk amorphous Cu52.5Ti30Zr11.5Ni6 and Cu53.1Ti31.4Zr9.5Ni6 alloys with a high glass forming ability can be quenched into single amorphous rods with a diameter of 5 mm, and exhibit a high fracture strength of 2 212 MPa and 2 184 MPa under compressive condition, respectively. The stress—strain curves show nearly 2% elastic strain limit, yet display no appreciable macroscopic plastic deformation prior to the catastrophic fracture due to highly localized shear bands. The present work shows clearly evidence of molten droplets besides well-developed vein patterns typical of bulk metallic glasses on the fracture surface, suggesting that localized melting induced by adiabatic heating may occur during the final failure event.

Reliability Distribution of Numerical Control Lathe Based on Correlation Analysis

Combined Reliability distribution with correlation analysis,a new method has been proposed to make Reliability distribution where considering the elements about structure correlation and failure correlation of subsystems.Firstly,we make a sequence for subsystems by means of TOPSIS which comprehends the considerations of Reliability allocation,and introducing a Copula connecting function to set up a distribution model based on structure correlation,failure correlation and target correlation,and then acquiring reliability target area of all subsystems by Matlab.In this method,not only the traditional distribution considerations are concerned,but also correlation influences are involved,to achieve supplementing information and optimizing distribution.

Simulation on the spatio-temporal distribution and emission flux of dust aerosol over East Asia in 2000-2009

A regional climate model （RegCM3）, coupled with an online dust module, is used to simulate the spatio-temporal distribution and emission flux of dust aerosol （smaller than 20 Wn in diameter） over East Asia in the period from 2000 to 2009. The model perfor- mance is firstly evaluated against available observations. Simulation results show that the model can capture the characteristics of spa- tio-temporal distribution of dust aerosol very well over East Asia. There always exist two extremes of dust aerosol optical depth （AOD） and column burden （CB）, one is in the Taklimakan Desert of Xinjiang Uygur Autonomous Region, China, and the other is in the Ba- dain Jaran Desert of Inner Mongolian Autonomous Region, China. The maximum value of CB appears in spring, secondary maxi- mum in winter and minimum in autumn. To the east of 110°E, dust is transported eastward from a maximum center at a height of 700 hPa over the East Asian continent. Dust emission sources are mainly located in the Taklimakan Desert, Badain Jaran Desert, North Qinghai-Tibetan Plateau and Southwest Mongolia. There is also an obvious seasonal variation of dust emission flux （EF）. Annual mean dust EF is 1,015.34 mg/（m2.d）, of which 62.4% and 2.3% are re-deposited onto the East Asian continent through a dry and wet deposition process, respectively, and the remaining 35.3% is injected into the atmosphere or subject to long-range transport.

Generalized Extended tanh-function Method for Traveling Wave Solutions of Nonlinear Physical Equations

In this paper, the generalized extended tanh-function method is used for constructing the traveling wave solutions of nonlinear evolution equations. We choose Fisher＇s equation, the nonlinear schr＆#168;odinger equation to illustrate the validity and ad-vantages of the method. Many new and more general traveling wave solutions are obtained. Furthermore, this method can also be applied to other nonlinear equations in physics.

Numerical Investigation of Plasma Active Flow Control

Based on the theory of EHD （electronhydrodynamic）, a simplified volume force model is applied to simulation to analyze the traits of plasma flow control in flow field, in which the cold plasma is generated by a DBD （dielectric-barrier-discharge） actuator. With the para- electric action of volume force in electric field, acceleration characteristics of the plasma flow are investigated for different excitation intensities of RF （radio frequency） power for the actuator. Furthermore, the plasma acceleration leads to an asymmetric distribution of flow field, and hence induces the deflection of jet plume, then results in a significant deflection angle of 6.26° thrustvectoring effect. It appears that the plasma flow control technology is a new tentative method for the thrust-vectoring control of a space vehicle.

Structure and Dynamic Characters of New Radar Stabilized Platform

Aimed at requirements, a kind of radar stabilized platform with external rotor and orthogonal shafts is designed. Its dynamic characters are analyzed by using finite element theory and ANSYS software. Also, a traditional stabilized platform with inner rotor is designed for comparison. It is shown that the new platform reduces two transmission links and 20% of precise components, its weight decreases by 20%, its natural frequency and rigidity are enlarged, the operating accuracy and stationary are increased. The new stabilized platform is more superiority and practicability. Its design method and analysis results have already been used in development mission. It provides helpful reference for similar structure designs.

A Novel Uniplanar Multi-Electrode Capacitive Sensor for In-Situ Weathering Damage Detection of Nonmetallic Materials

A uniplanar capacitive sensor with 5-electrodes on one plane substrate and a large reflector electrode,was designed to get the corresponding capacitance information for weathering damage detection of non-metallic materials exposed to a service environment.A 2-D finite-element method was employed to simulate the electric potential distribution and capacitance measurements for the sensor.2 marble slabs,one was healthy and the other was notched,were experimentally detected.Both the simulation and the preliminary experimental results show that the measured capacitances decrease after weathering damage occurs in nonmetallic material.The reflector can enlarge the sensitive depth.The weathering assessment of nonmetallic materials can be done by processing the measured capacitances.The proposed approach can effectively detect the weathering damage of nonmetallic material and can be practically used for in-situ weathering damage evaluation.

Influence of sample temperature on the expansion dynamics of laser-induced germanium plasma

In this paper, we investigated the influence of sample temperature on the expansion dynamics and the optical emission spectroscopy of laser-induced plasma, and Ge was selected as the test sample. The target was heated from room temperature（22 °C） to 300 °C, and excited in atmospheric environment by using a Q-Switched Nd：YAG pulse laser with the wavelength of 1064 nm. To study the plasma expansion dynamics, we observed the plasma plume at different laser energies（5.0, 7.4 and 9.4 mJ）and different sample temperatures by using time-resolved image. We found that the heated target temperature could accelerate the expansion of plasma plume. Moreover, we also measured the effect of target temperature on the optical emission spectroscopy and signal-to-noise ratio.

Research on Key Technologies of Detecting 1553B Avionics Data Bus Network

1553B avionics data bus network may fail due to vibration,temperature,humidity or human error.Therefore,the research on detection technology of 1553B avionics data bus network is an important subject.The key technologies are studied by analyzing the possible faults of the network,including four-wire DC resistance measurement method for conductors-to-shield short test and stub continuity test,equivalent impedance measurement of coupling transformer for main bus continuity test,polarity reversal test base on duty ratio measurement,attenuation measurement base on coupler model,and data path integrity test base on bit error rate calculation.Finally,the implementation methods of key technologies are researched,a portable integrated automatic test system of 1553B data bus network is constructed based on PC 104 computer,and the hardware configuration and test process are especially designed.

Forward-headed structure change of acetic acid–water binary system by stimulated Raman scattering

The acetic acid-water binary system is a classical hydroxy-carboxy mixed system, while new and interesting phenomena appear under stimulated Raman scattering(SRS).Compared with the weaker signal of the acetic acid-water binary system obtained in spontaneous Raman scattering, SRS provides a finer band and a relatively distinct structural transition point.The structural transformation points are respectively at 30% and 80% by volume ratio under the condition of spontaneous Raman spectroscopy, while they are respectively at 15% and 25% under the condition of SRS.This phenomenon is attributed to the generation of laser induced plasma and shockwave induced dynamic high pressure environment during SRS.

Linear and Nonlinear Optical Properties of Novel Multi-branched Oligomers

我们调查统一多分叉的 truxene 的依赖相片物理的性质的 fluorene-vinylene 基于的 oligomers (Tr-OFVn， n=14 ) 采用的不变的吸收和排放光谱学，短暂吸收光谱学，二光子的荧光，和 z 扫描技术。增加 fluorene-vinylene 联合起来导致的结果表演一在吸收和荧光的系列红移动，并且弄短激动的州的一生。同时，二光子的荧光效率和 truxene 的二光子的吸收十字节逐渐地基于 oligomers 与结合的长度的延期在同伴提高。另外，十字节在 sum-over-state 上建模的二光子的吸收的价值来临与试验性的同意很好。结果显示多分叉的 truxene 基于忍受手臂为二光子的应用正在答应器官的材料的 oligo (fluorene-vinylene ) 的 oligomers。

Theoretical Prediction for Structural Stabilities and Optical Properties of SrS, SrSe and SrTe under High Pressure

结构的稳定性和在高压力下面的 SrX (X = S， Se 和 Te ) 的电子性质上的调查基于有飞机波浪基础的功能的理论(DFT ) 是在 CASTEP 代码实现了设置了的密度用第一原则的计算被进行。我们的结果证明三混合物的导致压力的阶段转变的顺序是 NaCl 类型(B1 ) 结构(Fm3m ) 到 CsCl 类型(B2 ) 结构(Pm3m ) 。阶段转变和 metallization 压力理论上被决定。光性质上的压力效果被讨论。结果与以前的计算和试验性的数据相比。