Study of Underwater Target Recognition for Torpedo Electromagnetic Fuse with High Detecting Precision

鱼雷武器系统的主动电磁引信回波信号中蕴含着雷目交会过程重要特征信息。针对回波信号能量比较法受到直达场耦合成分和噪声影响的问题,提出了基于数字信号处理技术的目标特征提取算法。对接收天线的回波信号进行全相位二次补偿处理;采用短时傅里叶变换对目标回波信号进行包络解调;再利用改进的三次多项式最小二乘拟合方法,以抑制数据波动影响并提高计算效率;提出一种基于钟型脉冲的参数识别算法对回波包络极大值点进行估计。仿真和试验数据验证表明所提出方法具有一定的工程实用性。Characteristic information is hidden in the received signal of active torpedo electromagnetic fuse.The conventional burst controlling strategies based on energy-comparison are affected by ambient and electromechanical noises.The improved algorithms based on digital signal processing techniques are proposed.The received signals are first processed by all-phase compensation method to eliminate the direct coupling component,and then the residual signal is demodulated using STFT.An improved polynomial least mean square approximation method,which reduces the computation time,is presented for eliminating the side-effects brought by noise.A parametric estimation model base on bell-shape impulse is used to estimate the maximum of echo envelope.Simulation and trial data show that the proposed algorithm is effective and practical.国家自然科学基金项目(51275384、51275382); 国家科技重大专项(2010ZX04014-016

化学合成共生二枚貝の貝殻形成に伴う硫黄解毒メカニズム

http://www.godac.jamstec.go.jp/darwin/cruise/yokosuka/yk19-10/

天山云杉林生物量及其变化规律的研究/Study of Biomass of Picea schrenkiana var.tianschanica and Its Variation[J]

选择新疆天山山脉从西到东处于不同经度位置3个地点(巩留、乌鲁木齐和哈密)的天山云杉林群落进行垂直样带调查,根据所调查数据及已建立的回归方程推算了不同地点天山云杉林的生物量,并分析了其随海拔梯度和林木径级的变化规律.结果表明:不同地点天山云杉林生物量变化在100.921t·hm-2和436.915 t· hm-2之间,不同地点天山云杉生物量总体呈现西部大于中东部的趋势,天山云杉生物量随海拔梯度和林木径级的变化总体上都呈现单峰型