High-spin yrast and yrare structures in 112In

Up to now, no experimental cross-section data exist for the ⁶⁷Zn (n,a \alpha) ⁶⁴Ni reaction in the MeV neutron energy region. In the present work, the cross-section of the ⁶⁷Zn (n,a \alpha) ⁶⁴Ni reaction was measured at E _n = 6.0 MeV. Experiments were performed at the Van de Graaff accelerator of Peking University, China. Fast neutrons were produced through the D (d, n) ³He reaction using a deuterium gas target. Absolute neutron flux was determined by a small ²³⁸U fission chamber and a BF₃ long counter was used as a neutron flux monitor. A twin gridded ionization chamber was employed as the a \alpha -particle detector and two back-to-back ⁶⁷Zn samples were used for a \alpha events measurement. Background was measured and subtracted from foreground. The measured cross-section of the ⁶⁷Zn (n,a \alpha) ⁶⁴Ni reaction was 7.3 (1±15%) mb at 6.0MeV. The present result was compared with existing evaluations and TALYS code calculations.     

Indium distribution and light emission in wurtzite InGaN alloys: Several-atom In-N clusters

Considering various In distributions, we investigate electronic structures and light emission of wurtzite In_xGa_1 − xN (0?x?1) alloys. We find In_xGa_1 − xN forms a random alloy, in which many several-atom In-N clusters and short In-N- chains can exist. Small In-N clusters, especially in-plane ones, strongly localize valence electrons and dominate light emission in Ga-rich In_xGa_1 − xN alloys, which is consistent with experiments.     

基于磁偶极子构造法几何建模的铁管磁异常正演

地下铁磁性金属管线受地球原磁场磁化产生磁场会改变原地磁场分布,而形成地磁异常;通过管道几何建模和磁偶极子构造法对管道磁异常进行正演分析;首先利用近似的立方体单元对管道进行几何建模并输出相应的立方体单元体积和中心坐标;然后将立方体单元近似为磁偶极子,使用磁偶极子构造法进行管道磁异常正演;最后研究了距径比,磁倾角,磁偏角,地球场强,管道材料磁化率对管道磁异常正演的影响;研究结果表明:在6倍距径比外,同一球面上测点磁异常值接近一致, 且管道磁异常正演结果不受磁倾角,磁偏角和材料磁化率的影响;随着地磁场强度增大,管道磁异常呈线性增大;研究成果将为自主研发高精度磁异常地下管线探测设备奠定理论基础。     

高阶效应对超短艾里-高斯脉冲相互作用的影响

本文运用分步傅里叶变换,对满足高阶耦合非线性薛定谔方程的超短艾里脉冲与超短高斯脉冲,利用MATLAB数值模拟了在高阶效应下两脉冲相互作用后的演化过程以及时域上的强度变化.获得了负三阶色散效应使超短脉冲相互作用能传输更远距离;正三阶色散效应会减慢超短脉冲相互作用的传输.自陡峭效应通过孤子分裂现象的形式使超短脉冲相互作用产生时域位移.内拉曼效应可以将超短脉冲相互作用的能量由前沿处转移到后沿处.     

基于改进模糊聚类法的维修专业设置方法研究

针对当前数字化部队存在维修保障专业冗余、维修人员闲置、维修保障资源使用冲突的问题,对功能相似的维修专业进行合并重组提高维修保障效率。在现有基于装备功能组成的维修专业设置的基础上,运用改进的模糊聚类法对现行二级维修专业进行分类聚合,构建基于装备技术构成的维修专业设置模型。该模型对功能相似的冗余维修专业进行合并,可以减少维修专业冗余和维修人员的闲置,避免维修保障资源使用的冲突,为数字化部队维修专业设置提供可行方案。     

水中兵器一体化试验总体设计探讨

一体化试验是一种统筹试验项目、共享试验资源、综合试验信息、提高试验质效的试验鉴定模式。为全面考核水中兵器战术技术指标和作战使用性能,介绍了武器装备试验类型,分析了水中兵器试验面临主要问题,从模式上提出了水中兵器一体化试验需求,从构想上提出了一体化试验总体框架、基本目标和实现思路,从方法上探讨了一体化试验验前分布构建、验前信息相容性检验、验后分布确定和多源信息融合,从要求上提出了一体化试验体制管理和质量管理,为实现水中兵器一体化试验总体设计提供技术途径。     

The research on semi-active muffler device of controlling the exhaust pipe’s low-frequency noise

In order to control low frequency noise in exhaust pipe, this paper puts forward a new concept of H-Q tube based semi-active muffler device. The semi-active muffler device and bench testing system have been designed and operated. Finite element simulation study on semi-active muffler and experimental study on semi-active muffler and passive muffler have been carried on. The effect of simulation and experiment are consistent. The semi-active muffler device acts well in low frequency band, especially between 50 Hz and 150 Hz. The average level of noise reduction is around 35 dB, which is much better than passive muffler. Between 150 Hz and 350 Hz, semi-active muffler has a better performance than passive muffler; above 350 Hz, it has worse performance compared with the passive muffler.     

Analysis of outage probability for radio over IsOWC system in the presence of pointing error

In this paper, we analyze the outage probability of the radio over intersatellite optical wireless communication system in the presence of satellite vibration with bias error. The lower-based Mach–Zehnder modulator, optical booster amplifier and optical preamplifier are employed. First, the models of the proposed system and channel are given. Then the outage probability for a given bit error ratio (BER) of a quadrature phase shift keying signal is obtained in the presence of satellite vibration with bias error. Numerical results of outage probability with different bias error and average BER are given. Results indicate that the outage probability is obviously influenced by the pointing error and the optimum telescope diameter to minimize the outage probability exists. With the same pointing error condition, the value of the optimal telescope diameter will increase with the reduction of the given average BER.