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71.
针对军机制造过程越来越精细,质量要求越来越高,研究了军机全寿命周期制造过程中产生的各种BOM及BOM之间的关系;建立了质量信息数据库模型,并提出了军机架次质量信息数据库模板,对质量信息进行了有效的集成和共享,增强了对数据的传递性、完整性和准确性;为保证军机制造质量奠定基础. 相似文献
72.
Olga Prieto-Ballesteros Elena Vorobyova Victor Parro Jose A. Rodriguez Manfredi Felipe Gómez 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
Planned future exploration missions to the Jovian satellite Europa have a strong astrobiological motivation. Characterization of the potential habitability of the liquid water environments, and searching for life signals are the main astrobiological objectives of these missions. To meet these objectives specific strategies and instrumentation are required. Here we discuss some scenarios for the development of Europa potential biospheres. These scenarios are based on assumptions of the life similarity concept and knowledge about terrestrial life in extreme environments. Since the potential habitable environments on Europa are in the interior of the satellite it is not possibly to directly detect life. However, there are processes that link aqueous sub-surface environments with the near-surface environment, such as tectonism or magmatism. Therefore, by analysing endogenous materials that arise from the interior it is possible to make predictions about what is in the sub-surface. We propose some measurements and instrumentation for future missions to detect biosignatures on the upper layers of Europa, including the simple physico-chemical traces of metabolism to complex biomolecules or biostructures. Raman spectroscopy or biosensor technologies are the future for in situ exploration of the Solar System. 相似文献
73.
Multiaxial fatigue life prediction of composite materials 总被引:1,自引:0,他引:1
In order to analyze the stress and strain fields in the fibers and the matrix in composite materials,a fiber-scale unit cell model is established and the corresponding periodical boundary conditions are introduced.Assuming matrix cracking as the failure mode of composite materials,an energy-based fatigue damage parameter and a multiaxial fatigue life prediction method are established.This method only needs the material properties of the fibers and the matrix to be known.After the relationship between the fatigue damage parameter and the fatigue life under any arbitrary test condition is established,the multiaxial fatigue life under any other load condition can be predicted.The proposed method has been verified using two different kinds of load forms.One is unidirectional laminates subjected to cyclic off-axis loading,and the other is filament wound composites subjected to cyclic tension-torsion loading.The fatigue lives predicted using the proposed model are in good agreements with the experimental results for both kinds of load forms. 相似文献
74.
为了避免由于航空发动机部件性能退化,导致单一寿命延长控制器为延长部件寿命,过分限制发动机基本性能,进而使得发动机不能满足正常使用需求,在分析发动机性能退化对其基本性能及部件寿命影响的基础上,根据不同性能退化水平设计软中硬三级寿命延长控制策略,并利用双层控制系统结构来协调多个控制器间的切换。仿真结果显示,自适应寿命延长控制系统可以准确地评估发动机部件性能退化情况,并选择合适的寿命延长控制策略,从而在保证发动机全寿命期内基本性能的基础上,延长部件寿命。 相似文献
75.
介绍了一种光电式电子水平仪的设计方法,运用CCD传感器敏感硅油液面建立水平基准,通过计算机系统实现光电信号的采集、处理及显示。通过对光电式电子水平测量原理的分析,详细阐述了光电式电子水平仪的总体技术实现、硬件技术实现和软件技术实现,并完成了光电式电子水平仪的原理样机,进行了技术指标的测试,达到了预期效果,具备了工程应用的价值。 相似文献
76.
Min Chen Sufang DengYouquan Yang Yibing HuangChongchu Liu 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2012
Azolla shows high growth and propagation rates, strong photosynthetic O2-releasing ability and high nutritional value. It is suitable as a salad vegetable and can be cultured on a multi-layered wet bed. Hence, it possesses potential as a fresh vegetable, and to release O2 and absorb CO2 in a Controlled Ecological Life Support System in space. In this study, we investigated the O2-providing characteristics of Azolla in a closed chamber under manned, controlled conditions to lay a foundation for use of Azolla as a biological component in ground simulation experiments for space applications. A closed test chamber, representing a Controlled Ecological Life Support System including an Azolla wet-culture device, was built to measure the changes in atmospheric O2 and CO2 concentrations inside the chamber in the presence of coexisting Azolla, fish and men. The amount of O2 consumed by fish was 0.0805–0.0831 L kg−1 h−1 and the level of CO2 emission was 0.0705–0.0736 L kg−1 h−1; O2 consumption by the two trial volunteers was 19.71 L h−1 and the volume of respiration-released CO2 was 18.90 L h−1. Under 7000–8000 Lx artificial light and Azolla wet-culture conditions, human and fish respiration and Azolla photosynthesis were complementary, thus the atmospheric O2 and CO2 concentrations inside chamber were maintained in equilibrium. The increase in atmospheric CO2 concentration in the closed chamber enhanced the net photosynthesis efficiency of the Azolla colony. This study showed that Azolla has strong photosynthetic O2-releasing ability, which equilibrates the O2 and CO2 concentrations inside the chamber in favor of human survival and verifies the potential of Azolla for space applications. 相似文献
77.
受控生态生保系统内红萍供氧特性研究 总被引:1,自引:0,他引:1
研究红萍载人供O2特征, 为红萍生物部件进行系统总体地面模拟试验及空间应用奠定基础,构建了受控生态生保系统密闭试验舱和红萍栽培装置, 在“红萍-鱼-人”共存情况下, 测定密闭舱内O2, CO2浓度的变化. 试验结果显示, 单位重量的鱼耗O2量. 0805~0.0831 L·kg-1·h-1, 排放CO2量为0.0705~0.0736 L·kg-1·h-1; 试验志愿者耗O2量19.71 L·h-1, 呼吸释放CO2量18.90 L·h-1. 人工光照保持7000~8000 lx条件下, 红萍的光合作用与人和鱼的呼吸作用相辅相成, 舱内O2, CO2浓度趋于平衡. 密闭舱内CO2浓度升高对促进红萍群体净光合效率有明显效果, 红萍光合放O2能力很强, 能有效促使密闭舱内O2, CO2浓度朝着有利于人生存的环境方向平衡, 进而验证了红萍的空间应用前景. 相似文献
78.
《中国航空学报》2021,34(4):225-240
Single-pass honing is an important machining method for finish machining of holes, which can meet the requirement for high efficiency and consistency of holes. Characterization and life prediction of single-pass honing tool are necessary to improve the machining accuracy of holes honed, especially dimension accuracy. Single-pass honing tool is a single layer abrasive tool with fixed dimension, which still remains problematic for characterization and life prediction. For fuel injection nozzles with bore diameter under 1 mm, the stiffness of the single-pass honing tool is poor. This article presents a novel analytical model that predicts life of the tool with poor stiffness. Firstly, according to the bore diameter and dimension tolerance, the single-pass honing tool is designed and manufactured. Based on the prepared single-pass honing tool, the measurement and characterization methods are established. Furthermore, the tool wear tests are carried out, and the tool contour evolution model is established to predict the tool life. 相似文献
79.
80.