内燃机驱动常温烟雾机的电气特性

内燃机驱动常温烟雾机的轴流风机动力是由本系统内燃机驱动的直流发电机提供。为了确定电气系统的组成构件及其规格、技术参数，本项目在二相流喷雾试验台上进行了逐项及组合性能试验。掌握了各要素的工作原理、技术性能、匹配参数及合适的工况点，为设计、研制内燃机驱动常温烟雾机提供了依据。     

农业可持续发展与改善生态环境

对可持续发展概念的提出、演变、含义以及把它作为我国经济发展的战略进行了综述,讨论了发展与环境的关系,农业可持续发展与改善生态环境的关系,分析了我国面临的生态环境问题,并提出了一些建议。     

黄土高原水土保持对农业持续发展的作用

通过大量事实分析了水土流失的危害及水土保持对农业可持续发展的作用,充分说明了水土保持是黄土高原农业走持续发展道路的可靠保证,也是改善生态环境和生产条件并防止山区水旱灾害,促进群众脱贫致富的根本途径。     

湖北农业可持续发展的途径

农业是湖北的优势产业,对长江沿岸经济发展与支撑能力建设起着至关重要的作用。湖北只有实现农业可持续发展,才有可能实现整个社会经济的可持续发展。湖北农业可持续发展面临的问题主要有：人口增长,耕地锐减,人地关系矛盾加剧;中低产田面积大,水土流失严重,农业生态系统抗灾性差;农业自然资源不合理开发利用现象比较普遍;农业环境污染日趋严重。为了解决上述问题,实现农业可持续发展,必须认真做到：因地制宜地大力推广各种生态农业优化模式;对全省各个农业区农业内部结构、生产布局进行合理调整;通过“种养加”相结合、“产供销”一条龙、“农工贸”一体化,构建生态工程,全面推进农业产业化;坚定不移地贯彻执行计划生育和环境保护两项基本国策,当前特别要注意控制农村环境污染及抓好灾后重建工作;要开展农业系统工程的研究,为各个农业区设计良性循环的系统模型,并在此基础上研究全省农业可持续发展的优化模式。     

The effect of disturbance by Phellinus weirii on decomposition and nutrient mineralization in a Tsuga mertensiana forest

Summary Microbial biomass in the upper 7 cm of soil and needle decomposition on the forest floor were measured seasonally for 10 months in a mountain hemlock (Tsuga mertensiana) old-growth forest and in a regrowth forest after Phellinus weirii, a root-rot pathogen infection, had caused disturbance. The microbial biomass was higher in the old-growth forest soil than in the regrowth forest soil. However, T. mertensiana needle decomposition rates were higher in the regrowth than in the old-growth forest. Total N, Ca, Fe, Cu, and Zn concentrations in needles increased during the 1st year of decomposition in both the old and the regrowth forests, but P, K, Mg, Mn, and B concentrations decreased. N, P, K, Mg, Cu, and Zn concentrations were lower in regrowth than in old-growth decomposing needles. During mineralization, needles in the regrowth forests released more N, P, and K as a result of higher needle decomposition rates. Our results suggest that higher needle decomposition rates increased the mineralization of N, P, and K, which may lead to increased soil fertility and faster tree growth rates in the regrowth forest.     

农业纤维物料压缩流变研究现状

分析了国内外农业纤维物料压缩研究的现状,指出了存在问题;（１）多属“闭式”小模型压缩试验研究。（２）理论研究与实际脱节。（３）在压缩过程中的影响因素考虑的不够全面。（４）对压缩过程被压缩物料的流变特性研究不够;（５）同时要求给出被压缩物料施加恒应力（或恒应变）,并指出应加强以下几个方面的研究;（１）不同喂入量以不同压缩频率压缩时的蠕变和应力缓弛问题,（２）压缩室内草片和草捆在不同位置的蠕变和应力松     

农业机器人视觉导航技术发展与展望

概述了农业机器人主要的导航方式，综合分析了目前国内外视觉导航研究现状及存在的问题，并提出了进一步研究的方向与途径。     

灌溉预报与节水灌溉决策专家系统研究

从节水灌溉的基本原理入手，分析灌溉预报中的各个参量，提出了节水灌溉决策的依据、方法及评价标准。介绍了灌溉预报决策专家系统中由框架库、规则组库和黑板3部分组成的综合知识体结构的知识表示技术。     

辽宁省东部山区5种森林植被类型水文生态效益综合评判

利用层次分析与Fuzzy数学相结合方法,对辽宁省东部山区5种森林植被类型水源涵养能力进行了多目标综合评判。首先利用层次分析法确定了评价因子林冠截留、林冠蒸散、枯落物蓄水、土壤容重、非毛管孔隙度、初渗速率、稳渗速率、土壤总蓄水和土壤有效水的权重集为C=(0.0245,0.0051,0.1993,0.0109,0.0762,0.0565,0.2827,0.0573,0.2866),然后利用最大模糊熵原则确定了评价因子的隶属函数,最后利用Fuzzy综合评判得出油松、落叶松、红松、柞木林、杂木林评价结果模糊子集为B=(0.4686,0.3784,0.4145,0.6128,0.4808),结果表明阔叶林水源涵养效益高于针叶林,其中柞木林效益最佳。     

Reciprocal transfer effects on denitrifying community composition and activity at forest and meadow sites in the Cascade Mountains of Oregon

In order to examine the effects of disturbance, vegetation type, and microclimate on denitrification and denitrifier community composition, experimental plots were established at the H. J. Andrews Experimental Forest in the Cascade Mountains of Oregon. Soil cores were reciprocally transplanted between meadow and forest and samples were collected after 1 and 2 years. Denitrifying enzyme activity (DEA) was measured using the acetylene block assay and terminal restriction length polymorphism profiles were generated with nosZ primers that target the gene coding for nitrous oxide reductase. Nitrate concentrations, C mineralization, and water content were measured to gain additional insights into soil properties controlling DEA. Meadow soils were significantly higher in DEA than forest soils, and the highest DEA levels were observed in cores transferred from the meadow into the forest. Nitrate concentrations were also different between forest and meadow soils, but did not correlate to DEA. DEA was higher in open versus closed cores, suggesting an association between denitrification and the rhizosphere. Denitrifier communities of undisturbed forest and meadow soils shifted through a 4-year period but remained distinct from each other. Similarly, denitrifier communities clustered by vegetation type of origin regardless of manipulation, suggesting that the overall denitrifier communities are well buffered against environmental changes.