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51.
The parallels between the challenges facing bioregenerative life support in artificial closed ecological systems and those in our global biosphere are striking. At the scale of the current global technosphere and expanding human population, it is increasingly obvious that the biosphere can no longer safely buffer and absorb technogenic and anthropogenic pollutants. The loss of biodiversity, reliance on non-renewable natural resources, and conversion of once wild ecosystems for human use with attendant desertification/soil erosion, has led to a shift of consciousness and the widespread call for sustainability of human activities. For researchers working on bioregenerative life support in closed systems, the small volumes and faster cycling times than in the Earth's biosphere make it starkly clear that systems must be designed to ensure renewal of water and atmosphere, nutrient recycling, production of healthy food, and safe environmental methods of maintaining technical systems. The development of technical systems that can be fully integrated and supportive of living systems is a harbinger of new perspectives as well as technologies in the global environment. In addition, closed system bioregenerative life support offers opportunities for public education and consciousness changing of how to live with our global biosphere.  相似文献   
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台湾军方对无人机的浓厚兴趣,是很早就开始了,不过由于无人机是敏感军事装备,因此台湾外购无人机一直受到限制。但是台湾通过无人机做大军事力量的野心仍在不断的扩张。台湾的无人驾驶飞机一直被认为是这样一种状态:总水平比较低,起步较晚,种类有限,主要军事用途包括战术侦察,战场与海岸监控,电子干扰和诱饵;商业用途包括交通监视,资源勘探,反走私,反偷渡等。[编者按]  相似文献   
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The space elevator in the context of current space exploration policy   总被引:2,自引:1,他引:1  
Mark S. Avnet 《Space Policy》2006,22(2):133-139
The space elevator is an advanced space transportation system that someday could replace chemical rockets as humanity's primary means of reaching Earth's orbit. However, before this can occur, a number of enabling technologies will need to be developed, and a variety of economic and policy questions must be addressed. The goal of this paper is to examine the feasibility of the space elevator in the context of current space exploration policy. The paper reviews the space elevator's critical enabling technologies and presents their wide variety of applications. The challenges of funding the space elevator and of building support for the program are discussed. The potential for international cooperation is considered, and the role of the space elevator in the Vision for Space Exploration is examined. The paper argues that each of the space elevator's component technologies ought to be developed independently to meet separate nearer-term objectives. The space elevator should be just one of many applications considered in making decisions to pursue research and development related to each component technology. The enabling technologies, once mature, might eventually be integrated in the construction of a full-scale space elevator from the Earth's surface to geosynchronous orbit and beyond.  相似文献   
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In this study we perform a continuous Morlet wavelet transform method in time series of secondary cosmic rays and 1 AU interplanetary medium parameters for the interval from October 2001 to October 2002. The near 13.5-day periodicity was obtained during late 2001, and it was remarkable for muon data. Even though some works have pointed out that the main activations of the 13.5 day recurrence in near-Earth solar wind are related, e.g., with the heliosheet crossings or to the occurrence at 1 AU of two high speed streams approximately 180° apart in solar longitude per solar rotation, we aim to show that the period of about half the solar rotation during the end months of 2001 present in muon time series was apparently due to the occurrence of non-recurrent interplanetary disturbances. The interconnections among successive Forbush decreases, recovery phases and gradual muon depressions (associated with corotating interaction regions) seem to play an important role in such 13.5-day periodicity.  相似文献   
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The development of a fiber based laser architecture will enable novel applications in environments which have hitherto been impossible due to size, efficiency and power of traditional systems. Such a new architecture has been developed by the International Coherent Amplification Network (ICAN) project. Here we present an analysis of utilizing an ICAN laser for the purpose of tracking and de-orbiting hyper-velocity space debris. With an increasing number of new debris from collisions of active, derelict and new payloads in orbit, there is a growing danger of runaway debris impacts. Due to its compactness and efficiency, it is shown that space-based operation would be possible. For different design parameters such as fiber array size, it is shown that the kHz repetition rate and kW average power of ICAN would be sufficient to de-orbit small 1–10 cm debris within a single instance via laser ablation.  相似文献   
57.
Commercial suborbital space flights will reach altitudes above 100 km, with 3–5 min of weightlessness bracketed by high-g launch and landing phases. The proposed frequency of these flights, and the large passenger population, present interesting opportunities for researchers in the life sciences. The characteristics of suborbital flight are between those of parabolic and orbital flights, opening up new scientific possibilities and easing the burden for obtaining access to 0g.  相似文献   
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Bedau MA 《Astrobiology》2010,10(10):1011-1020
This paper addresses the open philosophical and scientific problem of explaining and defining life. This problem is controversial, and there is nothing approaching a consensus about what life is. This raises a philosophical meta-question: Why is life so controversial and so difficult to define? This paper proposes that we can attribute a significant part of the controversy over life to use of a Cartesian approach to explaining life, which seeks necessary and sufficient conditions for being an individual living organism, out of the context of other organisms and the abiotic environment. The Cartesian approach contrasts with an Aristotelian approach to explaining life, which considers life only in the whole context in which it actually exists, looks at the characteristic phenomena involving actual life, and seeks the deepest and most unified explanation for those phenomena. The phenomena of life might be difficult to delimit precisely, but it certainly includes life's characteristic hallmarks, borderline cases, and puzzles. The Program-Metabolism-Container (PMC) model construes minimal chemical life as a functionally integrated triad of chemical systems, which are identified as the Program, Metabolism, and Container. Rasmussen diagrams precisely depict the functional definition of minimal chemical life. The PMC model illustrates the Aristotelian approach to life, because it explains eight of life's hallmarks, one of life's borderline cases (the virus), and two of life's puzzles.  相似文献   
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