高分辨率SAR图像分割及目标特征提取

提出了一种非监督SAR图像快速分割算法,对分割得到的目标区域进行特征提取.分割方法利用固体热扩散模型与图像尺度空间的等价性,在SAR图像初始分割的基础上,引入最大后验概率矩阵的各向异性多尺度平滑,在保持图像结构信息的同时滤除斑点噪声对于分割的影响.然后提取目标区域6个特征以详细描述目标,实验结果表明：该方法计算速度快,能够从获得的目标区域得到大量有用的信息.     

发动机热流传感器的蒸发冷却技术

本文介绍发动机热流传感器的设计和初步试验,描述了蒸发器的结构原理,从理论上并通过试验分析了影响蒸发器效率的某些因素,如:放气阀的预压力,水的充装量和散热头部的结构尺寸。试验表明,所设计的蒸发器达到了预定的性能指标。     

等热流条件下相变导热仿生优化

为强化微重力条件下相变材料的熔化释冷过程,采用仿生优化的思想和有限元方法研究了导热空间内高导热材料的最佳布置方案。研究表明,采用温度梯度的时间积分作为布置高导热材料的判断标准,可把导热仿生优化的思想的应用由稳态问题扩展到非稳态具有相变的问题。和人工构造方案法相比,仿生优化得到的方案可以明显强化释冷过程、降低热流入口温升;且能克服其工作量大,所得方案不一定包含最优方案的不完备性问题。     

Tolerance of wheat and lettuce plants grown on human mineralized waste to high temperature stress

The main objective of a life support system for space missions is to supply a crew with food, water and oxygen, and to eliminate their wastes. The ultimate goal is to achieve the highest degree of closure of the system using controlled processes offering a high level of reliability and flexibility. Enhancement of closure of a biological life support system (BLSS) that includes plants relies on increased regeneration of plant waste, and utilization of solid and liquid human wastes. Clearly, the robustness of a BLSS subjected to stress will be substantially determined by the robustness of the plant components of the phototrophic unit. The aim of the present work was to estimate the heat resistance of two plants (wheat and lettuce) grown on human wastes. Human exometabolites mineralized by hydrogen peroxide in an electromagnetic field were used to make a nutrient solution for the plants. We looked for a possible increase in the heat tolerance of the wheat plants using changes in photosynthetically active radiation (PAR) intensity during heat stress. At age 15 days, plants were subjected to a rise in air temperature (from 23 ± 1 °C to 44 ± 1 °С) under different PAR intensities for 4 h. The status of the photosynthetic apparatus of the plants was assessed by external СО₂ gas exchange and fluorescence measurements. The increased irradiance of the plants during the high temperature period demonstrated its protective action for both the photosynthetic apparatus of the leaves and subsequent plant growth and development. The productivity of the plants subjected to temperature changes at 250 W m⁻² of PAR did not differ from that of controls, whereas the productivity of the plants subjected to the same heat stress but in darkness was halved.     

一种用于出舱活动的相变储热／辐射器式热沉

首先讨论了出舱活动中的各种散热方案；然后介绍了一种相变储热／辐射器式热沉。给出了闭式散热系统设计的性能要求及相变材料的选取标准和计算方法。     

Three dimensional investigation of the shock train structure in a convergent–divergent nozzle

Three-dimensional computational fluid dynamics analyses have been employed to study the compressible and turbulent flow of the shock train in a convergent–divergent nozzle. The primary goal is to determine the behavior, location, and number of shocks. In this context, full multi-grid initialization, Reynolds stress turbulence model (RSM), and the grid adaption techniques in the Fluent software are utilized under the 3D investigation. The results showed that RSM solution matches with the experimental data suitably. The effects of applying heat generation sources and changing inlet flow total temperature have been investigated. Our simulations showed that changes in the heat generation rate and total temperature of the intake flow influence on the starting point of shock, shock strength, minimum pressure, as well as the maximum flow Mach number.     

Microstructure,thermophysical property and ablation behavior of high thermal conductivity carbon/carbon composites after heat-treatment

Uni-directional carbon/carbon composites with high thermal conductivity are suitable to supply continuous thermal protection for future reentry vehicles since they could reduce surface temperature and ablation rates simultaneously in harsh environments. In this work, the high thermal conductivity carbon/carbon composites were prepared by chemical vapor infiltration. After heat-treatment, both their open porosity and internal friction increase due to the fiber/matrix thermal expansion mismatch; while their thermal conductive performance become better due to more complete carbon structure. With raising heat-treatment temperature from 1800 °C to 2450 °C, the mass and linear ablation rates of C/C composites with fibers vertical to the oxyacetylene torch for 60 s decrease from 0.66 mg/s and 2.95 μm/s to 0.51 mg/s and 2.05 μm/s respectively. The improved ablation resistance is resulted from the increased thermal conductivity from 282 to 508 W/(m·K) and more carbon fibers exposed to the flame during ablation, which have better oxidation resistance than those of carbon matrix. While such ablation rates become larger for composites with fibers parallel to the flame, from 1.02 mg/s and 3.73 μm/s to 1.28 mg/s and 5.01 μm/s respectively since the ablation occurred more easily through gaps at the fiber/matrix interfaces, which become larger and are always exposed to the flame for this case.     

基于薄膜热电堆的新型高温瞬态热流密度传感器的研制

目前针对国内薄膜瞬态热流传感器一致性较差、制备工艺不成熟等问题，提出了一种基于光刻工艺和离子束溅射镀膜工艺的制备方法，200对T型金属薄膜热电偶沉积在10mm×10mm的水冷块上，测量1μm的氧化铝热阻层温差，从而得到瞬态热流密度值。对新型高温瞬态热流密度传感器进行比对法标定，一致性误差为0.211%，即工艺的一致性约为99.79%。实验表明，研制的新型高温瞬态热流密度传感器的一致性好,制备工艺具备良好重复性和可移植性，能够满足高温瞬态热流检测需要，为热流传感器的推广应用及标准化、批量化生产提供了良好的技术支撑。     

吸热燃料裂解催化剂CuAPSO-34的合成及性能

采用Cu离子对硅磷酸铝分子筛SAPO－34进行离子改进,成功合成出CuAPSO－34分子筛。通过XRD,SEM,EDX及NH3－TPD等分析手段对改性分子筛进行结构及酸性的表征和对照分析,表明Cu的掺入较好改变了SAPO－34分子筛的微观结构及表面酸性。通过对吸热燃料模型化合物－正庚烷进行催化裂解的对比试验,获得了转化率和低碳烯烃的收率数据。结果表明CuAPSO－34能明显提高催化活性,大幅降低裂解温度;且在经济裂解温度区间500℃－600℃对低碳烯烃的选择性亦有所提高,因而吸热 燃料能够提供更高的热沉。     

热处理工艺对30CrNiWVA钢的组织和力学性能的影响

研究了一种新型低合金超高强度钢30CrNiWVA经不同温度淬火，回火后的力学性能和微观组织的变化规律，结果发现，淬火温度在900－940℃，回火温度在340℃左右时，30CrNiWVA钢回火马氏体组织均匀细小，σb≥1700MPa,σ0.2≥1500MPa,δ5≥12%,ψ≥55%,Aku≥50J，可以满足某些航空结构件在350摄氏度回火后高强度和高韧性的要求。