铝合金腐蚀损伤演化数学模型

 对LY12 CZ铝合金试验件进行了腐蚀实验，着重考虑了腐蚀时间和腐蚀温度这两个参数。从电化学微观角度考察了腐蚀损伤的发展，利用蒙特卡罗方法对腐蚀损伤演化的概率模型进行模拟计算，并讨论了不同预腐蚀温度和时间对腐蚀损伤的影响，建立了腐蚀损伤度演化全过程的数学模型。此损伤演化数学模型的模拟结果与实验结果符合较好，可以用此模型来预测不同腐蚀环境下的腐蚀损伤情况。     

A new hybrid aerodynamic optimization framework based on differential evolution and invasive weed optimization

Since many aerodynamic optimization problems in the area of aeronautics contain highly nonlinear objectives and multiple local optima, it is still a challenge for most of the traditional optimization methods to find the global optima. In this paper, a new hybrid optimization framework based on Differential Evolution and Invasive Weed Optimization (IWO_DE/Ring) is developed, which combines global and local search to improve the performance, where a Multiple-Output Gaussian Process (MOGP) is used as the surrogate model. We first use several test functions to verify the performance of the IWO_DE/Ring method, and then apply the optimization framework to a supercritical airfoil design problem. The convergence and the robustness of the proposed framework are compared against some other optimization methods. The IWO_DE/Ring-based approach provides much quicker and steadier convergence than the traditional methods. The results show that the stability of the dynamic optimization process is an important indication of the confidence in the obtained optimum, and the proposed optimization framework based on IWO_DE/Ring is a reliable and promising alternative for complex aeronautical optimization problems.     

Analytical and semi-analytical investigations of geosynchronous space debris with high area-to-mass ratios

This paper provides a Hamiltonian formulation of the averaged equations of motion with respect to short periods (1 day) of a space debris subjected to direct solar radiation pressure and orbiting near the geostationary ring. This theory is based on a semi-analytical theory of order 1 regarding the averaging process, formulated using canonical and non-singular elements for eccentricity and inclination. The analysis is based on an expansion in powers of the eccentricity and of the inclination, truncated at an arbitrary high order.     

TC11合金热变形特性及变形参数对组织的影响

通过热模拟压缩试验,分析了TC11合金的高温变形特性及不同变形参数下的组织演化规律,用非线性回归方法建立了TC11合金Kumar型材料的本构关系,得出了TC11合金的高温流变曲线基本呈流变软化特征的结论;最后应用MSC,Autoforge软件对TC11合金某型号涡轮盘的等温锻造工艺进行了模拟式工艺设计,验证了TC11合金材料本构关系的工程适用性.     

枪黑色Ni/Sn合金在NaOH溶液中的析氢电催化性能

实验测出的电化学参数表明：在ＮａＯＨ溶液中电解制氢时，枪黑色Ｎｉ／Ｓｎ合金的析氢电催化性能比４５号钢和主硫镍的强很多，而且具有很主的电化学稳定性。     

Changes in the Structure of Comet Nuclei Due to Radioactive Heating

The initial structure of a comet nucleus is most probably a homogeneous, porous, fine-grained mixture of dust and ices, predominantly water. The water ice is presumably amorphous and includes considerable fractions of occluded gases. This structure undergoes significant changes during the early evolution of the nucleus at large heliocentric distances, due to internal radiogenic heating. Structural changes occur mainly as a result of gas flow through the porous medium: the gas pressure that builds up in the interior is capable of breaking the fragile structure and altering the pore sizes and porosity. These effects are modeled and followed numerically, testing a large number of parameters. This revised version was published online in June 2006 with corrections to the Cover Date.     

Linking Primordial to Solar and Galactic Composition

Evolution and composition of baryonic matter is influenced by the evolution of other forms of matter and energy in the universe. At the time of primordial nucleosynthesis the universal expansion and thus the decrease of the density and temperature of baryonic matter were controlled by leptons and photons. Non-baryonic dark matter initiated the formation of clusters and galaxies, and to this day, dark matter largely determines the dynamics and geometries of these baryonic structures and indirectly influences their chemical evolution. Chemical analyses and isotopic abundance measurements in the solar system established the composition in the protosolar cloud (PSC). The abundances of nuclear species in the PSC led to the discovery of the magic numbers and the nuclear shell model, and they allowed the identification of nucleosynthetic sites and processes. To this day, we know the abundances of the ∼300 stable and long-lived nuclides infinitely better in the PSC than in any other sample of matter in the universe. Thus, we know the exact composition of a Galactic sample of intermediate age, allowing us to check on theories of Galactic evolution before and after the formation of the solar system. This paper specifically discusses the nucleosynthesis in the early universe and the Galactic evolution during the last 5 Gyr.     

Conversations on the Habitability of Worlds: The Importance of Volatiles

Our scientific forefathers discuss the interrelationships between water, climate, the atmosphere, and life on Earth and other terrestrial planets at a workshop in Nichtchatel, Switzerland.     

可重构芯片体系结构及其发展趋势

可重构芯片同时兼具通用处理器的灵活性和专用处理器的高效性,还具有高可靠性、低能耗、低成本等优点,在半导体产品中逐渐兴起。介绍了目前的一些典型可重构芯片的体系结构,从功能重构实现方式和可重构硬件类型角度分析了可重构芯片的体系结构,探讨了可重构芯片多核异构和可演化的发展趋势。