共查询到20条相似文献，搜索用时 15 毫秒
1.
Gold SS 《Science (New York, N.Y.)》1973,179(4074):656-660
I have stressed the importance of economic growth and employment policies for the furtherance of women's career objectives. Legal action to remove discrimination, as well as transformation of attitudes and expectations, will prove but hollow successes if adequate career opportunities do not become available. For this reason, the employment outlook for professional women in the 1970's has been examined on the basis of three alternative views of the future. All three involve elements of uncertainty and would require adjustments in the labor market. In the first alternative, although the BLS projected an overall balance in the labor market, supply and demand were expected to be ill-matched in several professional sectors, entailing burdensome retraining for those finding themselves in the areas of excess supply. The more pessimistic variant, based either on failure to reach growth and employment goals or on deliberate pursuit of reduced growth goals-combined with population stabilization and increased productivity-would require such fundamental adjustments in the labor market as work-sharing and early retirement or deemphasis of career objectives. The optimistic variant posits economic and social needs great enough to warrant high growth rates and views an expanded labor supply as a factor enabling the economy to attain such growth rates and to extend the utilization of professional personnel in new as well as in established areas (31). The major burden posed by the optimistic variant involves the need to achieve social consensus on the goals of society and to maintain the commitment to those goals with energy and intelligence. 相似文献
2.
本文基于山东、河南、河北、安徽、广西以及云南6省(区)共251个肉鸡养殖场户的微观调研数据,对肉鸡粪便资源化利用的方式和成本收益情况进行研究分析。研究发现,除少量鸡粪废弃外,肥料化是肉鸡粪便资源化利用的主要方向。从资源化处理后的鸡粪类型和销售路径看,养殖场户鸡粪肥料化利用方式具体有自用、免费赠送、鲜粪出售或有机肥出售等几种。对不同地区和不同规模肉鸡养殖场户鸡粪处理成本收益分析发现,当前鸡粪处理成本偏高,资源化利用带给养殖场户的经济效益不显著,且不同肉鸡品种、不同地区以及不同规模肉鸡养殖场户之间鸡粪处理的成本收益均存在较大差异。从总体上看,除了种养分离以及有机肥使用成本高,弱化了还田需求之外,鸡粪资源化处理成本高、资源化产品市场体系不健全也对鸡粪资源化利用推进产生了阻碍。因此本文建议,应合理规划种养规模和布局,加强鸡粪处理与利用的规范化管理,扶持畜禽粪便资源化处理设施建设,引导畜禽粪便资源化产品市场体系形成。 相似文献
3.
In examining the potential role of hydrogen in the energy economy of the future, we take an optimistic view. All the technology required for implementation is feasible but a great deal of development and refinement is necessary. A pessimistic approach would obviously discourage further thinking about an important and perhaps the most reasonable alternative for the future. We have considered a limited number of alternative energy systems involving hydrogen and have shown that hydrogen could be a viable secondary source of energy derived from nuclear power; for the immediate future, hydrogen could be derived from coal. A hydrogen supply system could have greater flexibility and be competitive with a more conventional all-electric delivery system. Technological improvements could make hydrogen as an energy source an economic reality. The systems examined in this article show how hydrogen can serve as a general-purpose fuel for residential and automotive applications. Aside from being a source of heat and motive power, hydrogen could also supply the electrical needs of the household via fuel cells (19), turbines, or conventional "total energy systems." The total cost of energy to a residence supplied with hydrogen fuel depends on the ratio of the requirements for direct fuel use to the requirements for electrical use. A greater direct use of hydrogen as a fuel without conversion to electricity reduces the overall cost of energy supplied to the household because of the greater expense of electrical transmission and distribution. Hydrogen fuel is especially attractive for use in domestic residential applications where the bulk of the energy requirement is for thermal energy. Although a considerable amount of research is required before any hydrogen energy delivery system can be implemented, the necessary developments are within the capability of present-day technology and the system could be made attractive economically .Techniques for producing hydrogen from water by electrolysis, from coal, and directly from thermal energy could be found that are less expensive than those now available; inexpensive fuel cells could be developed, and high-temperature turbines could be used for the efficient conversion of hydrogen (and oxygen) to electricity. The use of hydrogen as an automotive fuel would be a key factor in the development of a hydrogen energy economy, and safe storage techniques for carrying sufficient quantities of hydrogen in automotive systems can certainly be developed. The use of hydrogen in automobiles would significantly reduce urban pollution because the dispersed fossil fuel emissions would be replaced by radioactive wastes generated at large central stations. The conversion of internal or external combustion engines for combustion of hydrogen fuel would probably have less economic impact on the automotive industry than the mass introduction of electric automobiles. However, this is a subject that requires more detailed study. All of the safety aspects of hydrogen utilization will have to be examined, especially the problems of safety in the domestic use and the long distance transport of hydrogen in pipelines at high pressures. It is our opinion that the various energy planning agencies should now begin to outline the mode of implementing hydrogen energy delivery systems in the energy economy. The initial transition to hydrogen energy derived from available fossil fuels such as coal should be considered together with the long range view of all the hydrogen being derived eventually from nuclear energy. By the year 1985 when petroleum imports may be in excess of the domestic supply, these plans could set the stage for the transition period from fossil to a predominantly nuclear energy economy able to supply abundant synthetic fuels such as hydrogen. Synthetic fuels will obviously be more expensive than fuels now derived from petroleum; however, there may be no other viable choice. Thus, it is essential that the analysis and technological feasibility of a hydrogen energy system be considered now. It is of vital importance to the nation to develop some general-purpose fuel that can be Produced from a variety of domestic energy sources and reduce our dependence on imported oil. 相似文献
4.
针对鱼蟹稻田飞虫捕食装置的离网型户外供能需求的问题,着重研究该装置的供能系统方案。基于户外供能合理性要求,采用小型风力发电机和太阳能电池板自主互补发电来进行能源供应;对小型风力发电机和太阳能电池板分别进行Matlab/Simulink建模,着重对叶轮的风能利用系数、叶尖速比和桨距角的相关性进行量化分析,利用单因素分析法对太阳能电池板进行分析;在桨距角确定的条件下,适当取值叶尖速比,能够获得最大风能利用系数。同时,在不同温度和辐射的条件下,太阳能电池板能够取得功率曲线的峰值,为风光互补的最大功率获取提供理论上的支持。针对离网型风光互补系统能源的合理化利用,提出混合供能的能量管理策略,符合该装置的供能需求,对户外同类型装置供能设计提供一定的参考。 相似文献
5.
Whipple C 《Science (New York, N.Y.)》1980,208(4441):262-266
The energy required to build and install solar space- and water-heating equipment is compared to the energy it saves under two solar growth paths corresponding to high and low rates of implementation projected by the Domestic Policy Review of Solar Energy. For the rapid growth case, the cumulative energy invested to the year 2000 is calculated to be (1/2) to 1(1/2) times the amount saved. An impact of rapid solar heating implementation is to shift energy demand from premium heating fuels (natural gas and oil) to coal and nuclear power use in the industries that provide materials for solar equipment. 相似文献
6.
农业部市场与经济信息司课题组 《农业展望》2013,9(1):4-7
详细分析了2012年以来中国农产品市场运行情况,在此基础上对2013年中国农产品市场走势进行展望,预计粮食价格将稳中有涨;棉糖价格下行压力凸现;食用油价格将高位运行;猪肉价格下行趋势或将改变,牛羊肉则继续上涨;蔬菜市场供给充足,水果价格稳中趋弱。同时,结合国际国内形势,提出了未来应重点关注的问题及相关政策建议。 相似文献
7.
杨正礼 《西北农林科技大学学报(自然科学版)》1990,(Z1)
本文提出的下丁家村3种生活能源结构优化方案,与现状结构相比,薪炭林起主导作用且比重有所提高;沼气能和太阳能的利用数十倍地增加;秸杆直接用作燃料的比例由31.6％降至13％;能耗成本降低24.93％～41.17%;全村纯收入增加13％以上。3种优化方案均可变原来的单一结构为多能互补的多维结构,均具有明显的经济效益和生态效益。 相似文献
8.
我国秸秆粉碎机的研究现状与展望 总被引：5，自引：1，他引：4
我国是生物质产出大国,随着对生物质能的不断开发与利用,对生物质的粉碎就显得十分的重要。该文概述了我国秸秆粉碎机的研究发展现状,研究了现有粉碎机如铡切式、锤片式、揉切式和组合式粉碎机的结构特点、性能参数及粉碎的基本原理,阐述了今后秸秆粉碎机的发展趋势,提出要重视对秸秆粉碎机的理论研究与创新,优化现有的粉碎设备,进一步改进和完善现有机型,使各种机型的主要工作部件实现标准化。发展一体化联合加工设备,大力开拓秸秆粉碎机的经济市场,从而提高经济效益。 相似文献
9.
替代还是互补？淀粉糖与食糖在食品饮料业中的应用趋势 总被引：1，自引：0，他引：1
【目的】探讨淀粉糖在食品饮料业糖的需求中可能达到的市场份额，并预测淀粉糖的需求增长趋势及其潜在的经济影响。【方法】利用基于创新扩散理论的逻辑斯蒂增长模型研究淀粉糖在食品饮料工业中对食糖的替代能力随时间变化的规律，并运用需求模型预测淀粉糖在食品饮料业中替代食糖的前景。【结果】中国糖的消费市场仍处于扩张期。淀粉糖的市场份额仍有10年左右的快速增长期，然而其增长速度较之前有所减缓。2020年淀粉糖的需求量将比2011年翻一番。淀粉糖消费量的增加会降低食糖需求的增长速度，并改变多年来食糖主导糖的消费市场的局面。研究结果还表明，食品饮料业因用淀粉糖替代食糖而降低的生产成本有利于消费者，但这会增加食糖的需求价格弹性。然而，用于食品饮料加工业的淀粉糖产业的发展对玉米市场的影响有限。【结论】淀粉糖需求增长最终取决于因使用淀粉糖所能带来的成本节约。目前，淀粉糖与食糖在中国糖的消费市场中是一定意义上的互补关系，而不完全是替代关系。 相似文献
10.
天然气管输定价方法研究 总被引：1，自引：0，他引：1
天然气价格是影响天然气利用的一个重要因素,作为销售价格构成的一部分,管输费对天然气价格具有一定的影响,其定价地促进国家天然气工业的发理大。对我国天然气管输费价格 在的总是进行了探讨与研究,介绍了两种天然气管输价格的定价方法,认为应针对不同的条件采用不同的定价方法。 相似文献
11.
以北京和山东两地果蔬批发市场为例,以大白菜和苹果的市场批发价格为对象,通过构建VAR模型,研究我国农产品产销两地市场的价格传导关系。结果表明:产销地批发市场之间存在双向的价格传递关系,互为Granger因果。销地批发市场价格对产地批发市场价格的冲击比产地批发市场价格对销地批发市场价格的更大,也就是销地果蔬的批发价格在价格传递过程中占主导作用。由此可以判断出,产销两地的批发价格传导属于"需求拉动型",因此针对农产品下游价格的宏观调控应该比对农产品上游价格的调控更有效。 相似文献
12.
对构建耕地保护区域补偿机制的设想 总被引：20，自引：0，他引：20
持续了20多年的快速经济增长,使我国的综合经济实力和人民生活水平有了极大的提高,但同时也面临着耕地数量和质量急剧下降、圈地运动的屡禁不止和我国耕地总量动态平衡变昧走形以及经济发展较快地区建设用地指标不足、欠发达地区指标用不完的严峻现实,究其原因主要是市场和政府双重失灵的存在。耕地面积的过速减少将影响我国的粮食安全,社会稳定和生态安全;建设用地指标的严重不足将影响我国经济的进一步发展。如何解决“吃饭”与“建设”的矛盾已成为我国现阶段土地管理工作的重点和难点,需要对现行土地管理制度进行创新——建立耕地保护的区域补偿机制。 相似文献
13.
2013年中国饲料市场总体相对平稳,呈现饲料工业总产量首次下滑、消费量略有下降、重要原料价格波动明显、主要产品价格上涨放缓的基本特点;展望未来10年,中国饲料工业生产量和消费量将缓慢增长,预计到2023年将分别达到22 989万t和23 422万t,年均增长率均为2.3%,显著低于过去10年7.6%和6.8%的发展速度;受成本上升的支撑作用,中国饲料产品市场价格预计将温和上涨,平均每年上涨幅度将达到1.1%。为适应中国饲料工业发展进入调整期的客观要求,建议政策面进一步加大产业政策扶持力度、强化信息监测预警能力和创新市场风险管理工具。 相似文献
14.
Sørensen B 《Science (New York, N.Y.)》1975,189(4199):255-260
Two possible futures for the industrial world may be distinguished: (i) Large amounts of low-cost energy become available and the more energy-intensive methods for extracting resources from lowergrade deposits continue to sustain industrial expansion until either the environmental impact becomes unacceptable or ultimate limits, such as climate disruptions, put an end to such growth. (ii) The cost of nonrenewable energy resources continue to rise, but a fixed amount of energy from continuous sources may be utilized at constant cost. In this case a lower production level may be set by the amount of energy that is available from renewable sources, and society may thus have to be reshaped with energy economization in focus. If it is possible to choose between these two alternatives, the choice should be based on a discussion of the pros and cons of each one, and in particular on the desirability of having to process an increasing fraction of the earth's crust in search of raw materials in order to maintain growth as long as possible. However, the availability, of the first option is far from certain and it thus seems reasonable to plan for the second alternative. I have tried to propose such a plan for a small, homogeneous geographical region, namely Denmark. The ceiling on the consumption of energy from continuous sources is chosen in accordance with the criterion of not having to convert a major part of the land area to energy-collecting systems. The proposed annual average energy consumption of 19 gigawatts by the year 2050 corresponds to solar energy collecting panels (in use only 50 percent of the time) with an area of roughly 180 square kilometers and a windmill swept area of about 150 square kilometers. These (vertical) areas constitute less than 1 percent of the total land area. The selection of solar or wind energy for different applications has been based on known technology and may be subject to adjustments. The project has been shown to be economically feasible according to estimates of the cost of various alternatives during the 25-year depreciation period adopted. However, the initial cost per energy unit produced is higher than that for most of the alternatives, so that action is not expected to be taken immediately as a result of purely private initiative. In a public economic evaluation, other factors must be considered in addition to the cost of energy per kilowatt-hour. At present, Denmark has over 10 percent of its labor force out of employment and a substantial deficit on its balance of payments, so that an early start on the solar and wind energy project, based on national industry, would have additional payoffs compared with energy systems based on imported technology or imported fuels. Several factories that are now being closed down as a result of the economic crisis could be adapted to the production of parts for solar or wind power systems, and the building industry, badly hit by unemployment, would receive legitimate work. 相似文献
15.
Hubbard HM 《Science (New York, N.Y.)》1989,244(4902):297-304
In the next several decades it is expected that the United States and the rest of the nations of the world will greatly expand their consumption of electricity. But many questions will accompany this expansion: Can we build enough generating capacity? Do we have enough energy resources? Can we accommodate centralized and dispersed needs, large and small applications, and the diverse requirements of all sections of the world? And can we increase consumption without increasing environmental degradation? Photovoltaics, which by means of solid-state technology turn photon energy into electricity, can make a substantial contribution toward fulfilling these energy needs. Historically, the drawbacks to photovoltaics have been cost and technological maturity. But more than a decade of research has greatly advanced the technology and has brought it to the point of entering large electricity markets. Advances in the next two decades should make it possible for photovoltaics to become one of the world's preferred technologies for generating electrical energy. 相似文献
16.
Advanced technology paths to global climate stability: energy for a greenhouse planet 总被引：6，自引：0，他引：6
Hoffert MI Caldeira K Benford G Criswell DR Green C Herzog H Jain AK Kheshgi HS Lackner KS Lewis JS Lightfoot HD Manheimer W Mankins JC Mauel ME Perkins LJ Schlesinger ME Volk T Wigley TM 《Science (New York, N.Y.)》2002,298(5595):981-987
Stabilizing the carbon dioxide-induced component of climate change is an energy problem. Establishment of a course toward such stabilization will require the development within the coming decades of primary energy sources that do not emit carbon dioxide to the atmosphere, in addition to efforts to reduce end-use energy demand. Mid-century primary power requirements that are free of carbon dioxide emissions could be several times what we now derive from fossil fuels (approximately 10(13) watts), even with improvements in energy efficiency. Here we survey possible future energy sources, evaluated for their capability to supply massive amounts of carbon emission-free energy and for their potential for large-scale commercialization. Possible candidates for primary energy sources include terrestrial solar and wind energy, solar power satellites, biomass, nuclear fission, nuclear fusion, fission-fusion hybrids, and fossil fuels from which carbon has been sequestered. Non-primary power technologies that could contribute to climate stabilization include efficiency improvements, hydrogen production, storage and transport, superconducting global electric grids, and geoengineering. All of these approaches currently have severe deficiencies that limit their ability to stabilize global climate. We conclude that a broad range of intensive research and development is urgently needed to produce technological options that can allow both climate stabilization and economic development. 相似文献
17.
18.
可再生能源的开发利用将从根本上改变21世纪全球的能源构成。综合分析了海南省的太阳能、风能、水能、地热能、海洋能开发利用现状,并提出了相关建设性意见。在可再生能源的开发利用中,注意综合考虑风能、太阳能、地热能、小水电、海洋潮汐能等的互补作用,使可再生能源占海南省能源的份额越来越大。 相似文献
19.
From an analysis of the long-run electric generating requirements of several representative utilities, it is concluded that the energy supplied by solar photovoltaic power devices will displace primarily base-load, and to a lesser extent intermediate, generating plants, even at relatively modest penetrations corresponding to several percent of the utility peak load. Attaching photovoltaic devices to the utility grid will not yield significant fuel oil savings over the long run, in which utilities approach the economic optimum generating mix, and will increase peak plant requirements. Utility capacity and fuel savings of photovoltaic devices are reported both for the case without storage and for the case in which the utility has access to load-leveling storage. 相似文献