基于华氏宏观经济数学模型的高等职业教育动态投入产出模型

伴随着经济的发展和产业结构的变化,高等职业教育越来越受重视,高职教育的投入产出关系也引起了人们的关注。通过分析高职教育的投入产出关系,应用华氏宏观经济数学模型建立了高等职业教育动态投入产出模型。它对分析高职教育各项投入的效率具有实际意义。     

基于热力耦合层合板雷击损伤特性分析

为研究复合材料层合板在雷电流作用下的烧蚀损伤力学特性,建立复合材料雷击热力耦合有限元分析模型,与文献实验结果对比验证模型的有效性。根据Hashin三维失效准则编写用户材料子程序,分别得出层合板雷击烧蚀区域周围出现的力学损伤、各层力学损伤分布以及首层在不同方向上的应力分布,分析得出层合板的烧蚀损伤随雷电流持续时间的变化规律。结果表明:由于存在较高的温度梯度,导致层合板出现较大的热膨胀应力,进而导致层合板内部产生各种力学损伤,即基体开裂、分层及纤维断裂;雷击电流施加时间、峰值电流与温度场均对层合板烧蚀面积产生较大的影响。     

Some peculiarities of longitudinal distribution of proton fluxes at high latitudes

Dynamical features of proton fluxes at high and middle latitudes were studied based on data measured by Sun-synchronous low-altitude (800 km height) polar-orbiting three NOAA series satellites: POES 15, 16, and 17 during the geomagnetic storm on January, 21–22, 2005. Data from three satellites that passed the Northern hemisphere along different MLTs allow reconstructing the longitudinal distribution of the proton fluxes. Measurements of protons with energies of 30–80 keV and 80–240 keV (the ring current energy range) by 0- and 90-detectors were used to evaluate and compare the longitudinal asymmetry of proton flux distribution measured in the regions equatorward and poleward of the isotropic boundary. It was found that during all the phases of the geomagnetic storm distribution of the maximum flux of precipitating protons (0-detector data) is sufficiently asymmetric. The maximal flux position along MLT is moving from pre-midnight sector in quiet time to post-midnight one before and during SSC and moving back during recovery phase. The longitudinal distribution of precipitation maxima demonstrates the local increase in afternoon sector (approximately at 13:30 MLT) and decrease in the dusk one during SSC. These features are evident consequence of the magnetosphere compression. To identify the origin of the particles, the locations of maximum fluxes have been projected to the magnetosphere. It was determined that during geomagnetic storm main and recovery phases maximum fluxes were measured at latitudes poleward of the isotropic boundary. To evaluate the trapped particle flux asymmetry, the particle fluences (90-detector data) were calculated along the satellite orbit from L = 2 to the isotropic boundary. The total fluences of trapped particles calculated along the satellite orbit show regular asymmetry between dusk and dawn during main and recovery phases. The maximal intensity of proton fluxes of both investigated populations located poleward and equatorward of the isotropic boundary is achieved during SSC. The total flux measured during crossing the anisotropic region can be considered as a proxy for ring current injection rate.     

A comparative study on acoustic damping induced by half-wave, quarter-wave, and Helmholtz resonators

The damping characteristics of three-type resonators, a half-wave, a quarter-wave, and a Helmholtz resonator are studied experimentally by adopting linear acoustic test. A quantitative acoustic property of sound absorption coefficient in a model enclosure with the resonators is measured and thereby, the acoustic-damping capacity of a resonator is characterized. For a comparative study on acoustic damping, the damping capacity of a half-wave resonator is compared with that of the other resonators. A half-wave and a quarter-wave resonators have the same damping mechanism, but a quarter-wave resonator has much larger damping capacity than a half-wave resonator with the same diameter of a single resonator. It is found that shorter length of a resonator has the advantage of longer one with respect to the damping capacity. The damping capacity of a Helmholtz resonator increases with cavity volume and does as the orifice length decreases. A Helmholtz resonator has the highest damping capacity of three-type resonators and a half-wave resonator has the lowest. Besides, a Helmholtz resonator requires the smallest number of resonators for optimal damping. The design criterion of each resonator on the optimal damping is provided by the normalized parameter of open-area ratio and the similarity behavior for the optimal damping is observed for various enclosure diameters.     

载机武器舱盖表面压力计算研究

对带有内埋武器舱盖的载机,采用结构重叠网格方法保证各舱盖与载机网格质量,通过求解三维定常、非定常Navier-Stokes方程,得到内埋武器舱盖开启过程的静态、动态复杂流场,分析了内埋舱盖开启过程中其内外壁的气动特性,通过分析发现内外壁分布压力变化各有特点,动态压力分布居于静态压力分布包络中,舱盖结构强度设计宜采取"动-静结合"方式。     

数控加工零件热场分布的虚拟仿真

利用有限差分法对金属零件在数控机械加工过程产生热量的分布进行了数值分析,为计算金属零件热应力变形提供基础,是虚拟制造中机械加工工艺过程规划虚拟仿真的一种新方法。     

Mercury’s Surface Composition and Character as Measured by Ground-Based Observations

Mercury’s surface is thought to be covered with highly space-weathered silicate material. The regolith is composed of material accumulated during the time of planetary formation, and subsequently from comets, meteorites, and the Sun. Ground-based observations indicate a heterogeneous surface composition with SiO₂ content ranging from 39 to 57 wt%. Visible and near-infrared spectra, multi-spectral imaging, and modeling indicate expanses of feldspathic, well-comminuted surface with some smooth regions that are likely to be magmatic in origin with many widely distributed crystalline impact ejecta rays and blocky deposits. Pyroxene spectral signatures have been recorded at four locations. Although highly space weathered, there is little evidence for the conversion of FeO to nanophase metallic iron particles (npFe⁰), or “iron blebs,” as at the Moon. Near- and mid-infrared spectroscopy indicate clino- and ortho-pyroxene are present at different locations. There is some evidence for no- or low-iron alkali basalts and feldspathoids. All evidence, including microwave studies, point to a low iron and low titanium surface. There may be a link between the surface and the exosphere that may be diagnostic of the true crustal composition of Mercury. A structural global dichotomy exists with a huge basin on the side not imaged by Mariner 10. This paper briefly describes the implications for this dichotomy on the magnetic field and the 3 : 2 spin : orbit coupling. All other points made above are detailed here with an account of the observations, the analysis of the observations, and theoretical modeling, where appropriate, that supports the stated conclusions.     

俯仰轴飞行品质的PIO准则计算

由于新技术的采用,现代飞机出现驾驶员诱发振荡(PIO)现象大大增加,因此PIO已成为危及飞行安全的主要因素之一。介绍了MIL—STD—1797A规范中的PIO预测准则和美国“人机耦合对飞行安全影响委员会”提出的准则,论述了这些准则要求的背景、机理和计算方法,最后以某机为例进行了PIO预测计算和分析。     

高超侧压式进气道参数分析及试验研究

分析了高超侧压式进气过第一、二溢流窗的溢流角随后掠角的变化规律，分析了溢流窗气流与主流相互作用而形成一道脱体曲面激波的原因，设计了侧压角为６°，后掠角３０°的直前缘及圆弧前缘两套高超侧压式进气道，在Ｍ５．３风洞中利用风洞壁面自然发展的附面层进行非均匀来流下进气道起动性能及总体性能试验，试验发现大量附面层吸入不仅对起动性能有重大影响，而且对总压恢复影响也极大。     

社会进步的双重尺度及其意义

社会进步是客观的自然历史过程，也是人们进行价值追求的过程。我们应从生产力尺度与人的尺度及其辩证统一关系出发对这一过程进行考察。科学社会主义的发展应体现生产力尺度与人的尺度及其两者的统一。本文从客观性、价值性两方面来考察社会进步的历史过程，对生产力尺度及人的尺度的科学内涵做出了独特的界定，并对两个尺度的关系做了较深入的探讨。