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1.
The Particle Beam Fusion Accelerator II (PBFA II) is presently under construction and is the only existing facility with the potential of igniting thermonuclear fuel in the laboratory. The accelerator will generate up to 5 megamperes of lithium ions at 30 million electron volts and will focus them onto an inertial confinement fusion (ICF) target after beam production and focusing have been optimized. Since its inception, the light ion approach to ICF has been considered the one that combines low cost, high risk, and high payoff. The beams are of such high density that their self-generated electric and magnetic fields were thought to prohibit high focal intensities. Recent advances in beam production and focusing demonstrate that these self-forces can be controlled to the degree required for ignition, break-even, and high gain experiments. ICF has been pursued primarily for its potential military applications. However, the high efficiency and cost-effectiveness of the light ion approach enhance its potential for commercial energy application as well. 相似文献
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21世纪前期我国能源发展的构想 总被引：2，自引：0，他引：2
围绕十五大报告中提出的２１世纪克国经济发展战略目标,拟出了一个相应的能源发展构想,并对与之有关的７个方面的问题进行了探讨。按照这一构想,２０５０年的同比国内生产总值将为１９８０年的９６倍,但同期能源消费的增长却仅是９．６倍;同时,主要能源经济指标将经发展中国家范围内处于较高水平。 相似文献
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高校实验室的建设是关乎学校科技研发和创新力水平的重要工作,必须引起有关部门
的重视,而在信息技术不断发展的前提下,许多学校已经借助有关技术完成了数字化校园的建
设,在高校实验室的管理方面,依托现代的互联网技术可以有效提高实验室的管理水平。在医
学的病毒学分支领域,仿真实验一直是一项比较重要,也比较有难度的任务,会对高校的教学效
果产生深刻意义,影响人才培养。本文将以病毒虚拟仿真实验室为主要研究对象,探究其在高
校实验教学中的应用前景。 相似文献
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Stephanopoulos G 《Science (New York, N.Y.)》2007,315(5813):801-804
Economic and geopolitical factors (high oil prices, environmental concerns, and supply instability) have been prompting policy-makers to put added emphasis on renewable energy sources. For the scientific community, recent advances, embodied in new insights into basic biology and technology that can be applied to metabolic engineering, are generating considerable excitement. There is justified optimism that the full potential of biofuel production from cellulosic biomass will be obtainable in the next 10 to 15 years. 相似文献
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上海大学图书馆在新上海大学重组之后注重特色信息资源的配置与建设,十年来已建成了6种特色信息资源。未来将对有特色的资源进行扩展和完善,对特色信息资源建设的新领域进行多渠道开拓和探索。 相似文献
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基于两体束缚问题的数值求解,给出了在Mathematica 5.0中求解广义矩阵本征值方法的两种程序方案与高斯基个数及形状的关联.以氢原子和Cornell势场下粲偶素为例,讨论了高斯基空间的选择,并得到符合标准能谱及波函数的数值计算结果. 相似文献
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本文介绍在日本国寺泉干燥中心测得的干湿谷混合干燥试验结果,分析混合干燥设施的能量消耗、干燥效率、物料品质等项技术指标。获得了混合干燥新技术开发的基础性数据。 相似文献
10.
甜高粱能源化利用优势的分析 总被引：2，自引：1，他引：1
随着生物能源开发利用研究的不断深入,越来越多的能源作物成为开发生物质能的新原料。甜高粱是1种新的能源作物,具有生物产量高、抗逆性强、种植范围广、乙醇转化率高、转化成本低和综合利用价值高等优势。今后,甜高粱将成为能源作物中的主力军,为人们提供源源不断的可再生能源。 相似文献
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In conventional greenhouse crop production the high level of energy input conflicts with international agreements on reduction of CO2 emission. To reduce absolute energy consumption, energy friendly greenhouse systems have to be designed. If today's available technology is applied energy saving will be too low to meet the standards in future. Therefore, new technology has to be developed on aspects ranging from improving the greenhouse insulation and light transmittance to climate conditioning and control and energy management. An important aspect is that the production system is converted from a production-driven to a consumer-oriented activity. Modelling and information technology are important aspects in the developments in interaction with other disciplines. 相似文献
12.
Use of carbon dioxide in enhanced oil recovery 总被引：1，自引：0，他引：1
Large volumes of oil will remain in U.S. oil reservoirs when standard recovery methods have been completed. Supercritical carbon dioxide can be used to recover part of that remaining oil. If carbon dioxide is dense enough, it extracts hydrocarbons from the oil to make a mixture miscible with crude oil. Such a mixture can recover 95 percent of the oil in controlled laboratory flow settings. Heterogeneity of reservoir rocks and the low viscosity of carbon dioxide reduce the fraction of oil recovered in projects to lower but still significant levels. With the construction of three pipelines to carry naturally occurring carbon dioxide from Colorado and New Mexico to Permian basin oil fields, large-scale implementation of enhanced oil recovery by carbon dioxide flooding is now beginning. 相似文献
13.
Scheschkewitz D Amii H Gornitzka H Schoeller WW Bourissou D Bertrand G 《Science (New York, N.Y.)》2002,295(5561):1880-1881
Singlet diradicals are usually not energy minima. As observed by femtosecond spectroscopy, they readily couple to form final sigma bonds. Substituent effects allow lifetimes to increase into the microsecond range. Taking advantage of the properties of hetero-elements, a diradical has been prepared that is indefinitely stable at room temperature. The availability of diradicals that can be handled under standard laboratory conditions will lead to further insight into their chemical and physical properties, raising the likelihood of practical applications, especially in the field of molecular materials such as electrical conductors and ferromagnets. 相似文献
14.
Lincoln GA 《Science (New York, N.Y.)》1973,180(4082):155-162
We can no longer afford to ignore the serious potential consequences of our lavish use of energy. Continuation of the present rate of increase, particularly with the trend to imported fuels, will lead in short order to a level of dependency on imports which is disturbing for both the national security and the balance of payments. The inevitable rise in the price of energy will presumably lead to some increases in the domestic energy supply. But our reserves, particularly in the preferred forms of petroleum, gas, and even low-sulfur coal, are finite. Thus, the energy problem must also be attacked from the standpoint of energy conservation. The forthcoming rise in fuel prices will, of course, make more attractive some forms of conservation which at present are economically marginal. Nevertheless, consumers, industry, and government will have to make difficult choices in the years ahead: between greater convenience and lower energy bills, between the high capital costs of energy conservation measures and the long-term dollar savings from increased energy efficiency, and between environmental protection and the availability of needed energy supplies. Existing capabilities and technology, on which short- and midterm improvements must be based, appear to offer substantial possibilities for reducing U.S. energy consumption within the next decade (11). Long-term solutions to the energy problem, however, will depend to a considerable extent on the continuing appearance of new technological capabilities for increased efficiency of energy utilization and increased integration of energy applications. The capacity for continuing technological advances is, of course, dependent in turn on a strong relevant scientific base. A word of caution is necessary. Recent experience has shown that technological advances alone will not solve the problem. The problem spans not only the traditional physical and engineering sciences but also those sciences which deal with human attitudes and actions, that is, the social sciences, and includes a more fundamental understanding of underlying economic principles. The challenge to all sectors of American science should be clear. 相似文献
15.
Weir JR 《Science (New York, N.Y.)》1967,156(3783):1689-1695
The successful development of nuclear power reactors that are economically competitive with other sources of energy has led us to believe that more economical reactors will be developed. But, in developing the next generation of reactors, a new set of problems must be overcome. One of the most important of these is that of the embrittlement of the structural materials at high temperatures as a result of the intense neutron fields in these advanced systems. The radiation-induced embrittlement at high temperatures is probably associated with helium produced in the materials due to (n,alpha) reactions with the metal, and in some alloys radiation-induced precipitation of compounds within the alloy may also play a role. We believe that the most serious longterm problem is the generation of helium. Our current understanding of the mechanism by which this radiation damage is produced has allowed us to effect some improvement in the behavior of conventionally produced structural alloys, through minor modifications of the normal working and annealing processes used in their manufacture. However, we may find that new alloys will have to be developed to withstand the service conditions in future nuclear power reactors. 相似文献
16.
Wolf M 《Science (New York, N.Y.)》1974,184(4134):382-386
On the basis of the estimated contributions of these differing methods of the utilization of solar energy, their total energy delivery impact on the projected U.S. energy economy (9) can be evaluated (Fig. 5). Despite this late energy impact, the actual sales of solar energy utilization equipment will be significant at an early date. Potential sales in photovoltaic arrays alone could exceed $400 million by 1980, in order to meet the projected capacity buildup (10). Ultimately, the total energy utilization equipment industry should attain an annual sales volume of several tens of billion dollars in the United States, comparable to that of several other energy related industries. Varying amounts of technology development are required to assure the technical and economic feasibility of the different solar energy utilization methods. Several of these developments are far enough along that the paths can be analyzed from the present time to the time of demonstration of technical and economic feasibility, and from there to production and marketing readiness. After that point, a period of market introduction will follow, which will differ in duration according to the type of market addressed. It may be noted that the present rush to find relief from the current energy problem, or to be an early leader in entering a new market, can entail shortcuts in sound engineering practice, particularly in the areas of design for durability and easy maintenance, or of proper application engineering. The result can be loss of customer acceptance, as has been experienced in the past with various products, including solar water heaters. Since this could cause considerable delay in achieving the expected total energy impact, it will be important to spend adequate time at this stage for thorough development. Two other aspects are worth mentioning. The first is concerned with the economic impacts. Upon reflection on this point, one will observe that largescale solar energy utilization will not cause a greater impact than other new energy sources, based on the reasoning that a self-consistent set of conditions will have to be fulfilled in order to achieve such large-scale use. Without cost competitiveness, other energy resources would fill the requirements, or, if their resource and cost structure also would create severe problems, the economic forecasts simply cannot be fulfilled. We also should not think of a "solar-only" energy future. First, there is still enough coal to last for several hundred years. Second, there should be enough fissionable fuel available to operate breeder reactors for a similar time span, and geothermal energy could satisfy some requirements for a long time. And finally, there may be fusion. It would be unlikely that any one of the available options should play a really dominant role. Rather, we should expect to be using an energy mix, just as we do now, with each energy source supplying the requirements which it can satisfy in the most suitable way, and solar energy should play an important role in this long-range future. 相似文献
17.
We have adequate theory and engineering capability to design, install, and use equipment for solar space and water heating. Energy can be delivered at costs that are competitive now with such high-cost energy sources as much fuel-generated, electrical resistance heating. The technology of heating is being improved through collector developments, improved materials, and studies of new ways to carry out the heating processes. Solar cooling is still in the experimental stage. Relatively few experiments have yielded information on solar operation of absorption coolers, on use of night sky radiation in locations with clear skies, on the combination of a solar-operated Rankine engine and a compression cooler, and on open cycle, humidification-dehumidification systems. Many more possibilities for exploration exist. Solar cooling may benefit from collector developments that permit energy delivery at higher temperatures and thus solar operation of additional kinds of cycles. Improved solar cooling capability can open up new applications of solar energy, particularly for larger buildings, and can result in markets for retrofitting existing buildings. Solar energy for buildings can, in the next decade, make a significant contribution to the national energy economy and to the pocketbooks of many individual users. very large-aggregate enterprises in manufacture, sale, and installation of solar energy equipment can result, which can involve a spectrum of large and small businesses. In our view, the technology is here or will soon be at hand; thus the basic decisions as to whether the United States uses this resource will be political in nature. 相似文献
18.
Observed sequences of large earthquakes are not consistent in either recurrence time or energy release; long-term prediction has been impossible even in areas, such as Parkfield, with well-defined recurrence intervals. The seismic gap hypothesis, which predicts characteristic earthquakes in areas of the circum-Pacific belt that have not produced recent great earthquakes, has also failed to predict the observed clustering of high-energy events. Models in which fractal scaling is broken at high magnitude predict that characteristic events and recurrence behavior will be unstable in time. The central predictions of these models are supported by recent observations at Landers and Big Bear in California. 相似文献
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调整种植业结构发展甜高粱生产 总被引：4，自引：0，他引：4
根据新疆农业结构调整的战略部署,畜牧业将作为新疆特色农业和主导产业得以快速发展.提高畜牧业的质量和效益,必须与饲草、饲料业的发展同步,确保草畜平衡.甜高粱是一种新兴的饲料、糖料和能源作物,生物产量很高,用途广泛,开发利用价值很大.大力发展高能作物和生物能源作物甜高粱,是新疆调整产业结构,调优种植业结构,促进高能饲料作物和再生性能源作物产业化开发的战略性举措之一. 相似文献