平均子弹群中心法在子母弹射击效率计算上的应用

针对子母弹射击时存在多组误差的问题,采用"平均子弹群中心法"将营、连和单炮子母弹射击时的多组误差转化为"二组误差型",讨论了该方法的适用范围,给出了各类误差相关系数及其与"二组误差型"下相关系数的关系。给出了用"平均子弹群中心法"计算子母弹射击效率的算例。该方法简单易行,能有效地计算出子母弹对目标射击的毁伤概率。

原子弹内爆法设计的数学基础

引爆原子弹有两种方法——子弹法和内爆法。子弹法是把两块亚临界体积的浓缩核裂变材料，例如铀(或钚)分开，引爆时让其中一块撞击另一块，使两块亚临界体积的核裂变材料合在一起，变成一块超临界体积，使之引爆。例如1945年8月6日在日本广岛爆炸的那颗铀弹。内爆法是内聚引爆法的简称，也叫做向心引爆法。

Elastoplastic response of functionally graded cemented carbides due to thermal loading

Finite dement formulations are used to simulate the evolution of the elastoplastic response of functionally graded cemented carbides （FGCC） due to thermal loading. The geometry of specimens is an axisymmetric solid cylinder with a two-dimensional gradient. The elastoplastic constitutive relationship is developed by constraint factors. Numerical results show that compressive stresses occur in the surface zone and tensile stresses in the cobalt rich zone when the temperature drops from the initial stress-free temperature of 800 to 0℃. The maximum value of the surface compressive stress is 254 MPa and the maximum value of the tensile stress is 252 MPa in the cobalt rich zones. When the cobalt concentration difference in the specimens is equal to or greater than 0.3, there is pronounced plastic flow in cobalt rich zone. When the temperature heats up from 0 to 800 ℃, the total plastic strain reaches 0.001 4. Plastic flow has a significant effect on the reduction of thermal stress concentration.

The Road to Self-Reliance of the First French Atomic Bomb

After World War II,the choice of the plutonium bomb as the technology roadmap for the first French atomic bomb was not a military issue,but rather one guided by civilian nuclear technology policy.After consideration of the amount of uranium to be mined,technical reserves,and the financial situation,the civilian nuclear energy project of the Commissariatàl’énergie Atomique(CEA)was based on plutonium and natural uranium as the fissile materials,which indirectly provided enough plutonium for the future development of a nuclear weapon.When the Fourth Republic decided to develop the atomic bomb,a“Common Core”was established with the CEA,a public institution,as the lead,assisted by the military.Faced by the US embargo of nuclear weapons technology,the co-existence of civilian and military branches and their collaboration to some degree in the CEA not only made it a civilian-military complex,but also facilitated breakthroughs in the core technologies of implosion,the plutonium core,the tamper,and the neutron source.The success of the first French nuclear weapons test on February 13,1960,announced that France was on its way to becoming self-reliant in the military use of nuclear science.

Elastic Scattering of CH_4 by Electron Impact

In this work we present a theoretical study on electrons scattering by CH4 in the intermediate energy range. More specifically, we report integral and differential cross sections for electron scattering by CH4 in the （10 - 300） eV range by the Schwinger multichannel method using plane waves as a trial basis set （SMC-PW）. To include exchange effects we have used the Born-Ochkur model. Our aim is to study the numerical stability of the cross sections and our calculated results compared with experimental data and theoretical studies are encouraging.

Unscented Particle Filter Algorithm for Ballistic Target Tracking

At present, the ballistic Target tracking has a higher demand in convergence rate and tracking precision of filter algorithm. In the paper, a filter algorithm was improved based on particle filter. The algorithm was carried out from the aspects such as particle degradation and particle diversity lack. A novel ballistic coefficient parameter model was built, and was expanded to the state vector for filtering. Finally, the improved algorithm was simulated by MATLAB software. The simulation results show that the algorithm can obtain better convergence speed and tracking precision.

Trajectory design for the Moon departure libration point mission in full ephemeris model

The lunar probe may still have some remaining fuel after completing its predefined Moon exploration mission and is able to carry out some additional scientific or technological tasks after escaping from the Moon orbit.The Moon departure mission for the lunar probe is the focus of this paper.The possibility of the spacecraft orbiting the Moon to escape the Moon's gravitational pull is analyzed.The trajectory design for the Earth-Moon system libration point mission is studied in a full ephemeris dynamical model,which considers the non-uniform motion of the Moon around the Earth,the gravity of the Sun and planets and the finite thrust of the onboard engine.By applying the Particle Swarm Optimization algorithm,the trajectory design for the transfer from the Moon-centered orbit to the L1 halo orbit,the station-keeping strategies for the Earth-Moon halo orbit and the construction of homoclinic and heteroclinic orbits are investigated.Taking the tracking conditions and engineering constraints into account,two feasible schemes for the Moon departure libration point mission for the lunar probe are presented.