外军赛博空间作战装备分析

由于灵活度高、成本低、隐蔽性好等特点,赛博武器在近年来国际上发生的几次重大战争中发挥了影响战争走向的作用,这促使各军事强国纷纷加紧研制赛博空间作战装备.从信息窃取、多域网络攻击、信息安全防护和态势感知四个方面分析了外军软杀伤赛博空间作战装备及其特点,从硬件后门技术和高功率微波武器两个角度阐述了外军硬摧毁赛博空间作战装备的发展情况,指出智能赛博防御系统是应对赛博空间威胁的关键,为赛博空间作战装备的发展提供借鉴和参考.     

航天器子结构模态综合法研究现状及进展

现代航天器结构十分复杂,无论采用计算方法还是试验方法进行分析都是十分艰难的。在这样的研制背景下,子结构模态综合法应运而生。系统地回顾和总结了三大类子结构模态综合法的发展历程和相应的改进,介绍了该方法在航天工程上的应用。采用该方法可极大地提高航天器型号的研制效率。提出了子结构模态综合法面临的问题。     

某卫星微振动建模与仿真

针对某卫星微振动力学环境,参考IME颤振分析建模方法,建立了一种卫星刚柔耦合多体动力学微振动仿真模型,并通过地面试验验证了利用微振动仿真模型预测卫星在轨微振动响应的有效性,阐述了卫星在轨微振动响应仿真计算预测方法。利用该微振动仿真模型能较准确地预测卫星在轨微振动响应以及微振动传递特性。     

泡沫铝合金镀镍工艺研究

本文研究了在高硅铸铝制备的泡沫铝合金样品上镀镍工艺,提出了一种确定泡沫铝合金表面积的方法。讨论了主盐、还原剂、络合剂、缓冲剂等配方主要成份和ｐＨ 值、温度等工艺条件对化学镀镍的沉积速度和镀层质量的影响,优化了前处理方法,从而得到了适合于泡沫铝合金的镀镍工艺。     

Mesh-dependence of Material with Softening Behavior

The issue of mesh-dependence emerges when the conventional continuum damage model is applied to handling the softening behavior. In order to circumvent the mesh-dependence, the non-local theory is introduced into the conventional damage model and the finite element formulas are derived for two-dimensional gradient-enhanced damage model. A new element is proposed in which the basic unknown quantities are displacement, non-local equivalent strain and the gradient of non-local equivalent strain. The element and constitutive equation proposed in this article are added to the finite element software ABAQUS through user subroutine UEL. Numerical results show that the gradient-enhanced damage model can eliminate the mesh-dependence and is effective for dealing with the issue of softening behavior.     

DELMIA在某民机前货舱门装配仿真中的应用

在现代自动化作业系统中,操作和管理的大多是一些复杂系统和各种数字化设备,这对操作人员观察周围环境和完成精准操作任务的要求很高。通过人机工程技术分析,可以对这些复杂、易错的任务逐个分析,合理分配注意力、安排操作顺序,既减轻操作人员的工作负荷又避免出错,切实提高人机工效。     

模具工业发展中的几个问题

叙述了对模具工业地位与作用的认识 ,分析了我国加入世贸组织对模具工业的影响 ,并提出了发展模具工业的政策措施建议。     

Mercury’s Weather-Beaten Surface: Understanding Mercury in the Context of Lunar and Asteroidal Space Weathering Studies

Mercury’s regolith, derived from the crustal bedrock, has been altered by a set of space weathering processes. Before we can interpret crustal composition, it is necessary to understand the nature of these surface alterations. The processes that space weather the surface are the same as those that form Mercury’s exosphere (micrometeoroid flux and solar wind interactions) and are moderated by the local space environment and the presence of a global magnetic field. To comprehend how space weathering acts on Mercury’s regolith, an understanding is needed of how contributing processes act as an interactive system. As no direct information (e.g., from returned samples) is available about how the system of space weathering affects Mercury’s regolith, we use as a basis for comparison the current understanding of these same processes on lunar and asteroidal regoliths as well as laboratory simulations. These comparisons suggest that Mercury’s regolith is overturned more frequently (though the characteristic surface time for a grain is unknown even relative to the lunar case), more than an order of magnitude more melt and vapor per unit time and unit area is produced by impact processes than on the Moon (creating a higher glass content via grain coatings and agglutinates), the degree of surface irradiation is comparable to or greater than that on the Moon, and photon irradiation is up to an order of magnitude greater (creating amorphous grain rims, chemically reducing the upper layers of grains to produce nanometer-scale particles of metallic iron, and depleting surface grains in volatile elements and alkali metals). The processes that chemically reduce the surface and produce nanometer-scale particles on Mercury are suggested to be more effective than similar processes on the Moon. Estimated abundances of nanometer-scale particles can account for Mercury’s dark surface relative to that of the Moon without requiring macroscopic grains of opaque minerals. The presence of nanometer-scale particles may also account for Mercury’s relatively featureless visible–near-infrared reflectance spectra. Characteristics of material returned from asteroid 25143 Itokawa demonstrate that this nanometer-scale material need not be pure iron, raising the possibility that the nanometer-scale material on Mercury may have a composition different from iron metal [such as (Fe,Mg)S]. The expected depletion of volatiles and particularly alkali metals from solar-wind interaction processes are inconsistent with the detection of sodium, potassium, and sulfur within the regolith. One plausible explanation invokes a larger fine fraction (grain size <45 μm) and more radiation-damaged grains than in the lunar surface material to create a regolith that is a more efficient reservoir for these volatiles. By this view the volatile elements detected are present not only within the grain structures, but also as adsorbates within the regolith and deposits on the surfaces of the regolith grains. The comparisons with findings from the Moon and asteroids provide a basis for predicting how compositional modifications induced by space weathering have affected Mercury’s surface composition.     

Aeroelastic two-level optimization for preliminary design of wing structures considering robust constraints

An aeroelastic two-level optimization methodology for preliminary design of wing struc- tures is presented, in which the parameters for structural layout and sizes are taken as design vari- ables in the first-level optimization, and robust constraints in conjunction with conventional aeroelastic constraints are considered in the second-level optimization. A low-order panel method is used for aerodynamic analysis in the first-level optimization, and a high-order panel method is employed in the second-level optimization. It is concluded that the design of the abovementioned structural parameters of a wing can be improved using the present method with high efficiency. An improvement is seen in aeroelastic performance of the wing obtained with the present method when compared to the initial wing. Since these optimized structures are obtained after consideration of aerodynamic and structural uncertainties, they are well suited to encounter these uncertainties when they occur in reality.