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一、我国微灌设备现状近几年 ,我国微灌设备的研制和生产迅速发展 ,以北京绿源公司为代表的微灌企业 ,从国外引进技术先进、生产效率高的内镶式滴灌管生产线和相关产品生产工艺 ,其技术和产品达到了 2 0世纪90年代国际水平 ,但总体来说 ,我国微灌技术与发达国家还有较大差距。现就我国微灌设备材料、产品技术性能、适用性等分析如下 :1.内镶式滴灌管 我国最早生产内镶式滴灌管的是北京绿源塑料联合公司。当时想引进以色列耐特菲姆公司的技术 ,因要价太高 ,于是只好在学习以色列滴灌技术的基础上 ,选用相类似的台风滴头 ,自行研制内镶式滴灌… 相似文献
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我国微灌设备现状和亟待革新的问题 总被引:1,自引:1,他引:0
1 我国微灌设备现状分析 近几年,我国从事微灌设备研制和生产的企业发展迅速,以北京绿源公司为代表的微灌企业,直接从国外引进技术先进、生产效率高的内 相似文献
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我国微灌经历了18年的科研、试点和推广的实践,目前各地出现了热切要求发展微灌的局面。我们面临的压力是如何针对存在的实际问题,逐个地加以解决,脚踏实地工作,把我国微灌技术推上一个新台阶。 相似文献
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我国微灌技术和设备现状及市场前景分析 总被引:6,自引:4,他引:6
简要地回顾我国微灌技术发展历史 ,总结我国微灌技术和设备材料研究与推广应用成果以及发展趋势。通过分析我国微灌设备材料技术性能、规格品种和适应性 ,指出我国微灌设备材料整体技术水平不高 ,适应力不足。同时对我国微灌发展前景进行了预测和分析 相似文献
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新疆微灌发展现状、问题和对策 总被引:15,自引:4,他引:11
新疆具有得天独厚的特色农业资源和发展微灌的极其优越的自然条件,通过对新闻微灌发展现状和存在主要问题的分析发展新疆微灌事业的对策,并对新疆的一次性膜下滴灌、渗灌及微灌推广等问题阐明了作者的观点。 相似文献
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《Journal of Agricultural Engineering Research》1998,69(3):249-254
A model to represent the discolouration of dried powder of carrots as a function of temperature was developed. Two types of carrots, Asian and European, containing large amount of lycopene and β-carotene, respectively, were tested. The dried powder was stored under an atmosphere with O2and at three different temperatures, 5,20 and 35°C. The surface colour of the powder was monitored during storage by a Hunter colour ratioa/b. In the proposed model, the rate of oxidation was assumed to be represented by the product of the fraction of concentration of oxidized pigment at arbitrary time and a specific rate of oxidation of pigment. The rate parameters in the proposed model were calculated by fitting the experimental data with smooth curves by trial and error at the end of the induction period but before discolouration took place. The frequency constant and activation energy, expressing the temperature dependence of the rate parameters, were expressed by the Arrhenius relation. The simulation results of a Hunter colour ratioa/bof dried powder at 25°C showed good agreement with the experimental data, suggesting that the proposed model was effective for the prediction of discolouration of dried powder of both types of carrot. The use of the induction period in the manner described may enable the shelf life of dried powder to be predicted. 相似文献
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感官检验棉花的品级,这是农村常见的一种检测手段.它的一个主要特点就是存在不确定性.这是由于检验员的品级检验水平存在一定的差异,其中有很多因素制约着检验的结果.文章对影响感官检验结果的因素进行了系统的分析. 相似文献
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The fractional outflow rate of water from the rumen, measured as the rate of disappearance of the chromium complex of ethylenediamine tetra-acetic acid, was related to a number of dietary factors. A multiple regression equation was derived which expressed fractional outflow rate as a function of the intakes of dry matter, ash, acid-detergent fibre and crude protein.The data analysed consisted of 243 observations for sheep on 59 diets, including forage, concentrate and mixed diets. The ranges covered by the data were: fractional outflow rate 0.7–3.6 day?1; dry matter intake 560–1400g/day; ash 4–30%, acid-detergent fibre 7–41%, crude protein 5–26 % of dry matter; there were no observations for sheep of less than 34 kg liveweight.The equation accounted for 56·3 % of the total variance. Between-sheep variance could not be calculated for the whole of the data but was undoubtedly substantial since, for a sixth of the data, it was known to account for 38 % of the total variance. 相似文献
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从灾害经济学的角度探讨了城镇供水优化调度的必要性和可能性,认为在缺水不可避免的情况下,对供水进行优化调度可以减小缺水带来的损失,产生较好的减灾效益,特别是可以大大减小严重干旱的灾害效应。并根据水资源的特性,提出了缺水损失的计算模式以及优化调度的原则和方法。 相似文献