剪切成像技术:针对复合材料无损检测的一种光学检测方法

随着复合材料构件被广泛地应用于航空、航天和船舶等各个领域,这些复合材料构件的安全对产品质量起到关键的作用,具有重要的经济价值。无论是制造过程还是维修过程,都需要对复合材料构件进行快速的缺陷检测。剪切成像技术是一种高效的、全方位缺陷检测技术,并被广泛地认为是针对现代复合材料构件的可靠的检测技术。本文将介绍剪切成像技术最新的发展动态和软件技术,并概述其应用潜力。     

Interpersonal relationships in isolation and confinement: long-term bed rest in head-down tilt position

The long-term bed-rest was organized by ESA and CNES, in order to simulate the physiological effects of weightlessness: eight volunteers had to stay 42 days in bed, in a head down tilt position (-6 degrees). There were two subjects in a room, they could not be alone and it was difficult for them to have their own personal space and intimacy. In these circumstances, as in outer space, interpersonal relationships were of prime importance. This situation enabled us, through systematic observation, to analyze the evolution of the relational behavior in dyads, and to quote some social indicators of adaptation. Results show significant withdrawal, and the time spent alone was marked by the emergence, during the experiment, of specific preferential activities. Behavioral contagion was observed in each dyad (people engaged in the same activities at the same time), except in the one case of abandon. Moreover, the highest rates of inactivity and withdrawal were noted in this case. Verbal indicators were useful to comment these results and showed that, for all the dyads, one of the two subjects always played a regulating role by expressing a very positive perception of the situation. These results emphasize the importance of psycho-sociological factors in isolation and confinement. Thus, it appears that different modalities of interpersonal relationships, and not only verbal interactions, play a significant role in adaptation to stress situations.     

Autonomic regulation of circulation and cardiac contractility during a 14-month space flight

The space flight of physician cosmonaut V.V. Polyakov, the longest to date (438 days), has yielded new data about human adaptation to long-term weightlessness. Autonomic regulation of circulation and cardiac contractility were evaluated in three experiments entitled Pulstrans, Night, and Holter. In the Pulstrans experiment electrocardiographic (ECG), ballistocardiographic (BCG), seismocardiographic (SCG), and some other parameters were recorded. In the Night experiment, only the ballistocardiogram was recorded, but a special feature of this experiment is that the BCG records were obtained with a contactless method. This method has several advantages, the most important of which are the possibility of studying slow-wave variations in physiologic parameters (ultradian rhythms) on the basis of recordings made under standard conditions over a prolonged period. The Holter experiment (24-hour electrocardiographic monitoring) used a portable cardiorecorder (Spacelab, USA). The obtained electrocardiographic data were used to analyze heart rate variability. In the first 6 months of the 14-month flight, the dynamics of cardiovascular parameters in V.V. Polyakov was virtually the same as in the other cosmonauts. The data obtained after the first 6 months of Polyakov's sojourn in space are unique and mention should be made of at least three important aspects: (1) activation of a new, additional adaptive mechanism in the 8th-9th months of flight, as is evidenced by alterations in the periodicity and power of superslow wave oscillations (ultradian rhythms) reflecting the activity of the subcortical cardiovascular centers and of the higher levels of autonomic regulation; (2) growth of cardiac contractility accompanied by a decrease in heart rate during the last few months of flight; (3) a considerable increase in the daily average values of absolute power of heart rate's variability MF component, which reflects the activity of the vasomotor center. Specific mechanisms of adaptation to weightless conditions appear to be associated with activation of higher autonomic centers. The hypothesis that central levels of circulation regulation are activated in a long-term space flight was investigated by analyzing of ultradian rhythms in nighttime. The data, received during the flight of V. V. Polyakov, show, that the process of human adaptation to long influence of weightlessness consists of a number of consecutive stages, during which the activation of more and more high levels of control system of physiological functions occurs.     

Electrical power subsystem initial sizing

The basics of performing the initial electrical power subsystem (EPS) sizing for a spacecraft using solar cells for an energy source and batteries for energy storage are covered. The basic engineering inputs are described. The outputs are the first estimate of the number of solar cells, the solar array area, and the number of batteries required. A spreadsheet program to keep track of the inputs, perform the calculations, and document the inputs and outputs was written