陕北农牧交错带牧草生产力分析

根据陕北农牧交错带的生态环境特点以及牧草生长发育过程对水热资源的要求和利用效率,运用迈阿密模型定量估算陕北农牧交错带七县区牧草自然生产力。并与牧草现实生产力进行比较。研究表明:陕北农牧交错带牧草现实生产力仅为自然生产力的30.80%。基本掌握了该区牧草生产力状况和特点,并据此提出了相应的开发战略和实施途径。     

Optimum Planting System for Energy Saving and Healthy Demanded

It is proved that planting is effective to improve environment both indoor and outdoor resulted from the functions of plants to clean air and save energy. So the contradiction between saving energy and comfort,healthy demanded by people can be solved by planting. The planting have being emphasized and expanded during recent years,but in the planting plan,just the function of beautifying the environment is concerned and the function of ecological and saving energy are neglected. The analysis on the ooptimum system of planting is to make the planting system as an organic composition in the effectiveness structure and space layout of the city. Based on the study on equivalent relation of different effects on environment, the optimum system of planting structure will be determined in order to achieve the integrated effects of planting on environment.     

Discussion about Saving Energy in Refrigeratory

Food refrigeration is regarded as a high energy consuming trade. Under the long period system of state operated enterprise,there are many phenomenons of ignoring energy management and wasting energy. Energy consuming is not very clear for production.Consuming in our country is far more than the international standard and there is a distance between the middle_westland and the eastland. As a enterprise that faces the international market,it is important for it to strength the management so that the cost can be reduced. Considering those phenomenons of ignoring energy management and wasting energy in refrigeratory at present, some measures such as improved the unreasonable operation process, strengthening the energy management and automation to realize automatizing operation are improved to reduce the cost for refrigeratory trades.     

The Application of Relevant Homology in the Unified Representation of Electromagnetic Potentials and Gauge Transformation

Electromagnetic potentials and gauge transformation are derived for non-cloSedexterior differential forms with the help of relevant homology.Since de Rham ccahomology is sure-ly a relavant homology. potentials for both closed and non-closed forms and the gauge transforma-tion ean be unified in terms of relavent homology.     

玉米人工合成群体产量相关性状选择潜势及杂种优势模式分析

采用NCⅡ遗传交配设计 ,以分属于不同杂种优势群的 6个自交系做测验种 ,与 6个合成群体组配成 36个组合。结果表明 :单株产量的GCA以LBM最高 ,其次为WBM ,从株型、穗型性状的SCA分析合成群体与自交系组成了 9个优良杂种优势模式。单株产量最高的组合为HZ85×WBM ,其均值为 10 8 75g。通过对优良杂优模式内的变异参数估计 ,在群体内有丰富的变异个体 ,具有很强的选择潜势。组合内个体产量分布以及出现的频率对选系和轮回选择具有明确的指导意义。人工合成群体具有丰富的遗传变异 ,分属于不同的杂种优势类群 ,具有多元种质的特性。作为选系和轮回选择群体 ,具有明显的选择潜势     

工业循环冷却水降温系统设计

在许多工业生产过程中,常需要大量的冷却水进行冷却。通常采用冷却塔等敞开式循环水降温设施,在高温、高湿大气条件下出口水温超限,此时为了正常生产的进行,只好加大低温新水补充量,从而造成水资源的浪费。为了合理利用和节约水资源,设计土壤蓄冷式降温系统。在夜间冷却塔有富余冷量的时候,把冷量储存在土壤中;在白天释放出来,满足高负荷需要。     

液压自由活塞发动机的节能方式研究

液压自由活塞发动机是将内燃机和液压泵集成于一体，实现动力非刚性传输的复合发动机。本文从其内部能量转换及外部能量回收两个方面，详细地分析和阐明了液压自由活塞发动机各种节能方式和实现途径，以液压挖掘机为例，强调液压自由活塞发动机作为中心液压站，结合二次调节及液压变压器技术，简单方便地实现群控节能。     

节水灌溉的水稻干物质积累C-R模型研究

介绍了水稻干物质模型的研究进展和Chapman-Richards模型的数学结构以及该模型在描述林木生长和不同生物种群生长过程中的应用，并根据国家“863”节水农业专项子课题现场试验资料，用Chapman-Richards模型模拟了水稻干物质积累过程。结果表明。用Chapman-Richards生长方程来模拟控灌水稻干物质积累过程中，Logistic模型拟合效果最好。并根据模型参数对水稻生长过程进行了分析。     

发展山园瓯柑节水喷灌机械配套节本增效技术

随着我国综合国力的稳步发展,城乡人民的生活水平也不断提高,发展瓯柑种植面积和提高产量,改善瓯柑品质,是人们物质生活的需要,也是我国新形势下农业产业结构调整的发展趋势,并带动山区农民共同致富,利国又利民。本文就温州地区发展山园瓯柑节水喷灌机械配套节本增效技术进行叙述,对于推广应用具有重要的现实意义。     

Effect of soil matric potential on tomato yield and water use under drip irrigation condition

Field experiment was carried out to investigate the effect of soil matric potential (SMP) on tomato yield, evapotranspiration (ET), water use efficiency (WUE) and irrigation water use efficiency (IWUE) under drip irrigation condition in North China Plain. The experiment included five treatments, which controlled SMP at 0.2 m depth immediately under drip emitter higher than −10 (S1), −20 (S2), −30 (S3), −40 (S4) and −50 kPa (S5), respectively, after tomato plant establishment. The results showed that different SMP affected irrigation amount and tomato ET. Irrigation amount decreased from 185 mm (S1) to 83.6 mm (S5) in 2004, and from 165 mm (S1) to 109 mm (S5) in 2005, respectively. The ET decreased from 270 mm (S1) to 202 mm (S5) in both years. However, it was found that SMP did not affect the tomato yield significantly, for the range of SMP investigated. Both WUE and IWUE increased as SMP decreased. The maximum WUE (253 and 217 kg/ha mm) and IWUE (620 and 406 kg/ha mm) were for S5 in 2 years, whereas the minimum WUE (178 and 155 kg/ha mm) and IWUE 261 and 259 kg/ha mm) were for S1 in 2004 and 2005. Based on the above results, therefore, it is recommended that if the tomatoes are well irrigated (SMP is higher than −20 kPa) during establishment, controlling SMP higher than −50 kPa at 0.2 m depth immediately under drip emitter can be used as an indicator for drip irrigation scheduling during following period of tomato growth in North China Plain.