对小水电、沼气池、省柴灶三个能源工程项目的综合评价

农村能源工程项目的建设不仅具有项目本身的经济效益，而且有更广泛的能源、间接的经济和生态效益。农村能源工程项目的建设除了受资金约束外，还有技术管理等方面的限制，甚至人们的习俗和心理状态都可能是能源工程项目的制约因素。因此，对农村能源工程项目的多种效益和多种制约的综合分析和评价，将使我们能更全面地考虑项目的综合效果，使有限的资金、人力、物力投入到综合效果最好的项目上去。     

华北山区草地资源及其生产力的研究

华北山区位于温带——暖温带，东经１０７°～１２３°，北纬３５°～４３°。包括山东丘陵区，太行山区，冀北辽西山地区，阴山山地区四部分。该区属于农牧业交错区，农业、牧业（农区牧业和草地牧业）、林业十分发达，并且在迅速发展。华北山区是我国小麦、玉米和杂粮的主要产区。草地类型多样，饲草料丰富，又是养牛业、养羊业、养猪业相当发达的地区。经统计，华北山区总人口为５６２９万，总土地面积３５４５万ｈａ，天然草地总面积为１５８８．９１万ｈａ，占土地总面积的４４．８２％，人均草地０．２８２３ｈａ。各个区的草地类型不同，生产力差异显著（ｐ＜０．０１）。     

农村电网中有源电力滤波器的研究

随着农村电网中电力电子装置的日益增多,农村电网中的谐波污染问题越来越严重.为此,简要分析了并联型有源电力滤波器的系统结构和工作原理;建立了采用DSP数字控制的适合于三相三线制的并联型有源电力滤波系统, 重点分析了该系统指令电流和PWM信号的产生、硬件结构与软件流程, 并通过实验验证了该系统可以有效地抑制农村电网谐波,改善农村电网电能质量.     

贵州省退耕还林与农村经济发展研究

通过对贵州省贞丰、桐梓、锦屏等若干县市林业生态建设监理、检查、造林实绩核查等工作的实践和研究，认为退耕还林工程与农村经济发展相结合，目前应加强以下工作：选择林业主导产业；林产业时间、空间的合理布局；树种、林种的结构优化；林业体制创新；实施相关配套工程。     

Rural depopulation and recent landscape changes in a Mediterranean region: Consequences to the breeding avifauna

We studied the vegetational and avifaunistic changes following rural depopulation in an area covering 2,600 ha north of Montpellier (Southern France). The study area is covered by a mosaic of Mediterranean habitats that includes cultivation, grasslands, shrublands, and woodlands and is representative of the natural features present and of the human usage practiced so far in this part of the Mediterranean. We sampled the vegetation and the bird fauna in the same 193 census plots in 1978 and in 1992. At both the habitat and landscape scales the cover of woody plants increased significantly. Open habitats tend to disappear. As a consequence the abundance of open-habitat bird species decreased significantly whereas the abundance of forest birds increased significantly. These changes favor a pool of forest species widespread in western Europe and reduce habitat availability for open habitat and shrubland species. Many of the latter are Mediterranean species whose distribution in Western Europe could become reduced under current landscape dynamics. Our observation of more woodlands and their typical birds and of less open habitats and their associated avifauna is not consistent with the traditional worry shown by the public and the managers about the regression of forests and woodlands in the Northern Mediterranean as a consequence of fire.     

The application of atomic force microscope in clinic diagnosis of erythrocytes

AIM: To investigate the application of atomic force microscope (AFM) in clinic diagnosis. METHODS: Topographic images and some parameters of large range field and microstructures of erythrocytes in the blood of normal subjects, lung cancer and myelodisplastic syndrome (MDS) patients were examined by atomic force microscope. RESULTS: Many clear topographic images of many erythrocytes, single erythrocyte, and microstructure of erythrocyte membrane surface were obtained. Many erythrocytes in lung cancer patients were found to change into echinocytes. One erythrocyte had 10-20 protuberances, most of which, with a mean width of 589. 0 nm and a length of 646. 7 nm, were on the edge of cells. The protuberances on the center of echinocytes are lodged and embedded. The erythrocytes of MDS patients were biconcave in shape. Many apertures with different diameters of tens to hundreds nanometer appeared on the surface of cell membrane. CONCLUSIONS: AFM can be widely applied in clinic pathological inspection, including quantification of cells, obtainment and comparison of many parameters (such as diameter, thickness, volume, surface, surface area/volume ratio), observation of topograph of single cell, and observation and comparison of membrane surface microstructure of cells, and so on.     

乡村生态学研究的尺度与等级特征

乡村生态学 ( Village ecology)的尺度和等级特征依赖一定空间区域 ,不同尺度所研究村落的特征也不尽相同 ,空间尺度的大小很大程度上决定于所研究村落的复杂性、稳定性及特征。在特定的空间尺度下 ,乡村的组成要素随着时间尺度的变化而变化 ,但变化速率受空间尺度大小的制约。乡村生态学研究具有等级结构 ,空间尺度决定所研究单元的等级位置。行政村 (中心村 )和自然村 (自然屯 )是乡村生态学研究的基本尺度     

农民旅游市场开发浅议

近几年 ,我国国内旅游发展迅速 ,城镇居民旅游市场日益成熟 ,无论出游人口还是旅游花费都明显增加 ,但农民旅游市场却没有得到应有的重视 ,旅游供给严重不足。鉴于农民旅游的重要地位 ,本文分析了当前农民旅游特征及其发展潜力 ,在此基础上尝试性地提出了开拓农民旅游市场的几点措施建议。     

对农村机电提灌站存在的问题及应做好的工作分析

随着现代社会的不断进步发展,科学技术越来越成为一个行业的核心竞争力,对于农业来说,运用科学技术解决好农业的水利问题,这对于农业的发展有很大的促进作用。农村机电提灌站就是为了解决农业的水利问题而建设的,下面笔者就农村机电提灌站存在的问题及应作好的工作和大家展开讨论。     

辽宁省农村土地流转的金融服务探索

随着经济全球化的发展和我国现代化产业结构的不断调整,粮食安全的支撑重要性越发明显,但农村目前的青壮年劳动力却面临主动或被动脱离土地的窘境。如何推动农村土地流转,提升土地利用率,增加农业生产效应,加强其相关金融服务是一项重要有效途径。通过研究,发现辽宁省农村土地流转的金融服务存在一系列的问题,并给出相应的政策建议。