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151.
In this century large-scale transformations have been carried out in the delta of the Rhine, Meuse and Scheldt in The Netherlands. The following principal consequences are considered: the loss of estuarine ecosystems, the change in the process of sedimentation and erosion, and the development of new aquatic and terrestrial ecosystems. The ecological consequences of the transformation of the Grevelingen estuary into a salt-water lake and some surprising developments are described briefly. The need for a limited restoration of the water exchange between the lake and the North Sea is indicated, as well as the major impacts of the exchange. The necessity for the maintenance or restoration of estuaries, the ecological development and the possibilities of the new lakes, and the management of these lakes by engineering structures are discussed. Careful land-use planning and ecosystem management, backed by research, are needed to make the fullest possible use of the potential offered by new lakes. It is also concluded that salt lakes have interesting perspectives.  相似文献   
152.
Based on the findings of the meeting of JSC experts on “Aerosol and Climate” (Geneva, 27–31 October 1980) the general research strategy consisting of three phases will be presented. The three phases are: Phase I: Sensitivity tests with available models Phase II: Improvement of climate models and data bases Phase III: Development of advanced climate models with internal aerosol generation and regulation processes. COSPAR's role within this research strategy is outlined.  相似文献   
153.
A survey is presented of the potential benefits, possible pitfalls, and anticipated testing needs of integrating inertial guidance systems with systems dependent on the availability of the electromagnetic spectrum. Commonly referred to as integrated communications, navigation, and identification avionics (ICNIA), these systems of the future offer the combined potential for superb positioning and secure communications. The general characteristics (if current development trends continue) of the next-generation inertial navigation systems (INS) are briefly presented, followed by key modular and conceptual issues in the synthesis of this INS with systems dependent on the EM spectrum. Modular issues as considered here are those related to detailed implementation and resulting efficiency. Conceptual issues are those related to overall military strategy and resulting effectiveness. An example of modular systems integration is given, and a few preparations which can be anticipated for the field testing of integrated systems are presented, followed by concluding comments  相似文献   
154.
155.
Cloudiness modulates the radiation budget at the top of the Earth-atmosphere system. For radiation balance studies, for climate diagnostic studies, and for climate modeling studies, it is important to know the sensitivity of both the outgoing longwave radiation and the net (absorbed solar minus outgoing longwave) radiation of the system to changes in cloudiness on a global basis. Based on a 45 month series of NOAA satellite scanning radiometer observations, estimates of the global distribution of these sensitivity parameters are obtained.  相似文献   
156.
157.
Mechanically stacked tandem cells consisting of GaAs thin-film upper cells and CuInSe2 thin-film lower cells have been developed to meet the increasing power needs projected for future spacecraft. The authors report the fabrication of the first highly efficient lightweight GaAs/CuInSe2 tandem cell on a 2-mil thick substrate, update recent performance improvements in thin-film GaAs/CuInSe2 tandem cells, and discuss their application to space power systems. The efficiency of 4-cm2 cells has improved to 21.6% AM0, the highest ever reported for a thin-film photovoltaic cell. Lightweight 4-cm2 tandem cells have been successfully fabricated with efficiencies as high as 20.8%. These cells weighed about 180 mg without optimized substrate trimming. Radiation and operating temperature effects on GaAs/CuInSe2 tandem cells are also discussed, and an interconnect scheme to form a voltage-matched string is described  相似文献   
158.
The LIPS III satellite, which was launched into a 1100-km circular orbit of 60° inclination in the spring of 1987, is discussed. LIPS III is a member of the living-plume-shield class of spacecraft, all of which were built around a simple sheet metal plume deflector. The purpose of LIPS III was to provide a testbed for space power sources. An overview of the LIPS III system is given, and the experiments submitted for it, all but one of which were photovoltaic in nature, are described  相似文献   
159.
The PAVE PACE Initiative has been established to validate system avionics concepts for advanced military aircraft. The author presents the rationale of why the advanced architecture established by the PAVE PILLAR program should be continued under PAVE PACE to achieve: practical and affordable airborne versions of modular parallel processing network architectures for many applications currently beyond real-time implementation, readily available avionics for use in all avionics and, greatly improved techniques to reduce the cost of software development and support. An approach to the overall design structure for future avionics is also presented that entails: the use of CAD (computer-aided design) tools to assist in the development of system, hardware and software requirements, the use of replicated hardware modules (some at the wafer level), the use of reuseable software modules and the use of CAD tools to tailor hardware/software modules for specific application requirements. Continued use of the PAVE PILLAR high-speed data bus and operating system is recommended as the means to integrate and control the data input and output of physically and functionally separate parallel networks  相似文献   
160.
A sequence of six well defined interplanetary structures (magnetic clouds) was identified in the solar wind and magnetic field measurements of Helios-1 from 29 June-01 July, 1980. (location 0.64–0.67 AU, C. Long. ~165°, C. Lat. ~5.8°). These structures were characterized by a large northward directed solar wind flow; by well defined directional discontinuities of mainly the ‘tangential-type’ at their beginnings and ends; by some increase in proton and by very pronounced increases in alpha particle number densities - each accompanied by sudden temperature decreases (or in one case by an increase); by some times an increase in magnetic field strength and by values of Nα/Np typical of the inner solar atmosphere. These structures are suggested to have been ejections from a succession (27–29 June, 1980) of Type II producing flares in Hale Region 16923 which coronagraph and X-ray (GOES) data indicate constituted a family of transient producing events. Only two interplanetary shocks were identified in the relevant Helios-1 records. It is suggested on the basis of observations of the directionality of certain of the flare related Type II bursts that some of these shocks could have been missed by the spacecraft. This implies that, in the absence of directional information, correlation of an observed interplanetary shock wave with a solar Type II burst may not always lead to a unique result.  相似文献   
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