Solar energy and electric utilities: should they be interfaced?

Analyses of the economics of solar collection in the firm- and shifting-peak cases (that is, with off-peak electricity indefinitely available or with a flat load curve) indicate that, for many important applications, solar energy systems that interface with electric utilities can be justified only in terms of the value of the off-peak utility fuels that they displace. In regions where off-peak electricity costs are low, the most economically efficient solar energy systems will be those that use electricity as the auxiliary energy source. This implies extremely low break-even costs for a number of important solar energy applications. In regions where the cost of off-peak electricity is higher than that of competing energy forms, the most economical solar energy systems will utilize auxiliary fuels other than electricity. The general conclusion is that conventional electric utility systems and most solar energy systems represent a poor technological match. The basic problem is that both technologies are very capital intensive. The electric utility, because of the high fixed costs of generation, transmission, and distribution capacity, represents a poor backup for solar energy systems. On the other hand, the solar collection system, because it represents pure, high-cost capital and because of its outage problems, cannot be considered as a part-load source of auxiliary energy for the electric utility system.     

小型柴油发电机组并联运行及其在农村综合利用的试验研究

本文提出用目前农村应用最普遍的12马力小型柴油机为动力,驱动8千瓦三相同步发电机,组成发电机组并联运行,解决无电或国电供应不足的农村用电问题,提出以粮食饲料加工、照明、供水等三方面一年的总用电量为一个村屯的最基本用电量,以它为确定发电机组数量的依据,同时提出对其综合利用的措施,为充分利用农村小型动力,发展工副业生产,为农村生产、生活用电的迫切需要,开辟了一条新途径。     

中国农村公共投资的准商业供给模式评价——以电力电话投资为例

利用来自全国6个省2 459个村的代表性的公共投资调查数据,对中国村级电力电话投资的准商业模式进行了评价研究。实证分析表明,作为利润最大化的单位,准商业企业对农村进行投资的策略,与政府实施农村公共投资(如道路等)的有所不同。如果没有政府管制,准商业化经营的电力电话公司在贫困的和地处山区的村庄的投资要少于在富裕的或平原地区的村庄。研究也发现,村庄拥有的关系网对村庄能获得的政府投资具有显著的正效应,但是对准商业模式供给的电力电话投资并不具有显著的效应。文章的结论主要是,在进行适当政府管制的前提下,准商业企业可以纠正自己的行为,从而在农村公共投资中采取更加减贫的策略。若此,准商业供给模式将可以在未来的中国农村公共投资中发挥更加重要的作用。     

户用分布式光伏对农户收入的影响——以中部地区Y县为例

户用分布式光伏对农户收入影响具有长期性,如何发挥分布式光伏在乡村振兴战略中的作用需进一步探索。本文以户用分布式光伏为例,利用中部地区Y县2014—2019年农户追踪数据,运用双重差分法,分析户用分布式光伏对农户收入的影响,探讨户用分布式光伏对农户收入影响的作用机制。结果表明,2014—2019年农户收入大幅度提升,其中建光伏农户的人均收入增长幅度大于未建光伏农户,户用分布式光伏使农户人均收入提高25.4%,其中经营性收入、财产性收入分别提高74.4%和444.5%,而工资性收入降低45.3%。户用分布式光伏是通过减少非农劳动时间和缩短非农就业空间距离降低农户工资性收入,增加经营性收入,从而影响人均收入。进一步分析发现,户用分布式光伏对非中心村农户的工资性收入和经营性收入影响大于中心村农户,劳动力能力越强的农户经营性收入上升幅度越大,工资性收入下降幅度越小。因此,建议统一维护光伏设施,促进劳动力要素有效配置;并依据劳动能力差异分层分配股份,降低劳动能力强的农户对政府补贴的依赖;另外,创新光伏产业发展模式,拓宽光伏产业增收渠道。     

风光互补发电系统在转地饲养蜂场中的应用研究

在蜂群转地饲养中,由于场地条件的限制,蜂农的生产、生活难以获取现有交流市电的支持,经过实地蜂场调研,目前蜂农多数使用光伏组件收集太阳能作为能提供源。蜂农在户外难免遇到连续阴雨或者多云天气,无法为蓄电池充电,现有装置就无法满足蜂农的要求。针对这种现状,以风光互补发电系统作为切入点,针对转地饲养蜂农供电问题进行研究,将风力发电与太阳能发电结合起来,弥补连续阴雨天供电不可靠的缺陷,同时能够保证用户均衡充足的用电需求,为蜂农野外养蜂作业提供新的技术理论参考。     

太阳能热水器自然转换功能及技术

太阳能热水器与电的自动转换,一方面加速了人们广泛应用太阳能,节省能源,清洁环境.另一方面方便了人民的生活,体现了智能化、自动化,同时强行转换又满足了人们的多方面的要求,迎合了市场,目前该技术还不够成熟,预测市场前景广阔.     

High-efficiency third-generation silicon solar cells

The results of investigating third-generation matrix silicon solar cells with an efficiency of more than 25% during conversion of concentrated solar radiation are given. Electrical and optical characteristics are discussed. Modern technologies of semiconductor electronics and nanotechnology will soon allow increasing the efficiency of matrix silicon solar cells to 40%.     

太阳能在智能生态农业中的应用

针对太阳能养殖、太阳能干燥、薄膜太阳能农业大棚、太阳能灌溉及太阳能杀虫灯等5个太阳能的利用技术进行了论述,并将太阳能技术与传统技术进行了比较,分析了各项技术的优缺点,探索了太阳能在农业生产方面进行利用的前景.     

基于GIS技术的城乡土地利用规划支持系统

根据地理信息系统理论和软件工程方法论,结合城市空间规划模型方法,空间数据引擎(spatial dataengine,ArcSDE),GIS应用方法,软件开发技术以及网络技术,探讨了基于GIS技术的城乡土地利用规划支持系统的关键技术和设计方法;提出了决策软件平台的体系结构和应用模型,以及计算结果的多样化表达.最终以SQL Server 2000数据库及microsoft dotnet平台为基础,利用C#完成了系统的开发.结果表明:基于GIS技术的城乡土地利用规划支持系统在实现城乡空间规划的定性、定量、定位相结合和规划决策支持方面具有良好效果.     

香蕉种植户技术需求行为及影响因素的实证分析——以广西香蕉种植户的调查为例

以广西8个县市(区)35个村组125户香蕉种植户的入户访谈资料为依据,运用多元Logistic模型实证分析香蕉种植户技术选择时的需求意愿及影响因素.发现除种植户自身特征外,种植户技术需求也受到了外部因素的影响,如技术诱导因素,风险因素,组织化因素等.实证结果表明,种植户急需的技术类型依次是病虫害综合防治技术,高品质管理...     

基于多源数据的村庄发展潜力评价及村庄分类

村庄是促进城乡发展的重要单元,厘清村庄发展潜力、合理划分村庄类型是推动乡村振兴战略的基础。本研究以广州市从化区为例,基于多源数据构建评价指标体系,进行村庄发展潜力评价,并结合潜力评价结果、POI（兴趣点）数据核密度分析、引力模型划分村庄类型。结果表明：从化区村庄发展潜力整体上较好,但发展潜力分布不均衡,呈现西南强、东北弱的空间格局,形成以城区为中心向外扩散的圈层结构;从化区村庄可划分为经济核心类村庄、集聚提升类村庄、相对稳定类村庄、规模控制类村庄、搬迁撤并类村庄5类,数量占比分别为14.23%、12.69%、23.08%、25.38%、24.62%。研究表明,基于多源数据进行村庄发展潜力评价具有时效性和普适性,结合发展潜力、POI数据、村庄竞争力划分村庄类型,可为村庄发展规划精细化实施提供参考。     

Photovoltaic materials

Solid-state photovoltaic cells are feasible devices for converting solar energy directly to electricity. Recent cost reductions have spurred an incipient industry, but further advances in materials science and technology are needed before photovoltaic cells can compete with other sources for the supply of large amounts of energy. In this article energy loss mechanisms in solid-state photovoltaic cells are examined and related to materials properties. Various systems under development are reviewed which illustrate some key concepts, opportunities, and problems of this most promising emerging technology. Areas where contributions from innovative materials research would have a significant effect are also indicated.     

Toward cost-effective solar energy use

At present, solar energy conversion technologies face cost and scalability hurdles in the technologies required for a complete energy system. To provide a truly widespread primary energy source, solar energy must be captured, converted, and stored in a cost-effective fashion. New developments in nanotechnology, biotechnology, and the materials and physical sciences may enable step-change approaches to cost-effective, globally scalable systems for solar energy use.     

深化我国乡镇管理体制改革的若干对策——安徽省乡镇管理体制改革试点透析

本文以当前我国乡镇管理体制改革正由局部试点向全面深化转变为宏观背景, 阐明了全面推进这一改革亟待解决的五大问题, 即关键是乡镇管理职能的重新界定及其转变, 核心是县乡事权关系的廓清, 基础是乡镇管理体制改革方案的科学制定, 前提是县乡村三级的改革联动, 而根本则是乡镇执政能力的建设。     

构建村镇低成本地理信息系统的方法研究

探讨了构建村镇低成本地理信息系统的难点,提出了降低地理信息系统数据成本和开发成本的方法,从系统体系结构、数据库设计、系统功能设计3个方面介绍了村镇低成本地理信息系统构建方案,最后对构建系统使用到的sdf文件存储、Ajax客户端浏览和XML等关键技术进行了说明.     

Economic feasibility of solar water and space heating

The economic feasibility in 1977 and 1978 of solar water and combined water and space heating is analyzed for single-family detached residences and multi-family apartment buildings in four representative U.S. cities: Boston, Massachusetts; Washington, D.C.; Grand Junction, Colorado; and Los Angeles, California. Three economic decision criteria are utilized: payback period, years to recovery of down payment, and years to net positive cash flow. The cost competitiveness of the solar systems compared to heating systems based on electricity, fuel oil, and natural gas is then discussed for each city, and the impact of the federal tax credit for solar energy systems is assessed. It is found that even without federal incentives some solar water and space heating systems are competitive. Enactment of the solar tax credit, however, greatly enhances their competitiveness. The implications of these findings for government tax and energy pricing policies are discussed.     

Changes in transition: technology adoption and rice farming in two Indian villages

The economic impacts of the Green Revolution have been studied widely, but not its social-cultural effects on different farming communities. The adoption of high yielding varieties (HYVs) of rice changed the nature of rice farming in the two West Bengal villages of Padulara and Naigachi. The villages present an interesting contrast of socio-economic and cultural change due to the differences in the level of adoption of agricultural technologies. This study documents the social and cultural impacts of agricultural technology adoption, specifically the effect on rituals which guided the stages of traditional rice farming and communal life. Agricultural rituals are being modified to suit the processes of modern rice farming, while family rituals are holding strong. The study also shows the evolving nature of rituals as it reflects new found wealth, gender roles, and economic class in these villages.     

农村人居环境质量客观评价指标体系研究

为了探究农村人居环境建设质量评价方法,填补相关研究空白,本研究基于美丽乡村视角建立了以村庄为空间单元的农村人居环境客观评价指标体系,由产业兴旺、生态宜居、乡风文明、治理有效、生活富裕5个一级指标和31个二级指标构成。采用综合指数测算法对村庄的人居环境客观指标予以评分,并进行了质量分级。结果表明：各村庄综合评分和一级指标的评分均有一定的差异,说明村庄人居环境发展具有不平衡性;一级指标中治理有效和生活富裕评分较低,有必要采取措施提高村庄治理能力,多途径发展农村经济增加农民收入。根据各村庄人居环境质量客观指标评分情况,将农村人居环境质量划分为优、良、一般和差4个级别。提出了促进农村人居环境发展的相关建议,确定以村庄为空间单元的农村人居环境发展目标与规划,建立以村庄为单元的农村人居环境客观指标统计制度,发挥农村基层组织的作用提高村庄人居环境治理能力,多途径发展农村经济增加农民收入。     

村镇住宅太阳能技术应用研究

从我国太阳能的资源及应用技术现状等方面入手,着重介绍了现阶段村镇住宅建筑中可利用的太阳能技术,并对不同的应用形式作了必要的分析。     

太阳能光伏发电系统在植物工厂中的应用初探

从降低植物工厂运行成本的角度出发,将太阳能光伏发电系统与植物工厂相结合,可将太阳能转变成电能后为植物工厂的运行提供能源。太阳能技术的应用,将有望降低植物工厂的运行能耗,减少植物生产对常规能源的依附。