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对温室园艺精量播种机与大田精量播种机之间的区别以及国内外播种机的类型和发展现状进行了论述,并对各种温室园艺精量播种机的工作原理及特点进行了简要分析. 相似文献
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针对温室大棚空间狭窄、大田气力式精量播种机无法进入作业,而现有小型机械式播种机播种精度低的问题,设计了适用于温室大棚的小型气力式蔬菜精量播种机,采用正负压双作用排种器提高播种精度,并通过更换排种盘配合不同的开沟分种装置实现不同蔬菜及不同行数的播种作业,提高了播种机的适应性。对排种器进行基于EDEM的离散元仿真分析,探究充种区种群运动规律和搅种装置性能。对整机进行田间试验,结果表明:漏播率≤5%,重播率≤5%,种子机械破损率≤1%,播深一致性合格率≥90%,各项指标符合蔬菜种植农艺要求。 相似文献
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穴盘精量播种机是工厂化设施园艺生产的关键设备.目前，国内农机市场缺少价格低、操作简单、效果好的气吸式穴盘播种机.为此，研究了气吸式穴盘播种器在不同类型蔬菜种子、气室真空度和吸种盘孔径条件下的播种性能,并在播种试验台进行了性能试验,得出了不同种子播种性能与气室真空度和吸种孔径的关系;同时,结合多方面实际因素设计,为开发适合我国国情的气吸式精量播种机提供了理论基础. 相似文献
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蔬菜精量播种机是一种能够实现高效、精准播种的农业机械化设备，主要应用于蔬菜种植领域。探讨了蔬菜精量播种机关键部件设计和试验，基于国内外蔬菜精量播种机研究现状，提出一种蔬菜精量播种机总体设计，对关键部件进行设计与选型，并对其进行了试验和优化。田间试验结果表明，该设计能够满足蔬菜精量播种机的要求，提高了种植的效率和质量。研究成果可以为农业机械化生产提供有力的支持，并有望推动蔬菜种植技术的进一步发展。 相似文献
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通过对玉米免耕精量播种机关键技术及结构特点进行阐述,指出目前玉米免耕精量播种机技术发展存在的主要制约条件,并给予相应的发展建议,提出未来玉米免耕精量播种机的主要发展趋势与研究重点,以期为提升免耕播种机的工作性能提供技术参考. 相似文献
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传统的精量播种机为机械式播种机,播种精度低、控制手段落后,同时播种过程容易出现播种深度过深、播种间距不均及作业过程不可视等问题。为解决这一难题,深入研究集成电路技术,将集成电路应用在花生精量播种机的电气系统中,完成了基于集成电路的花生精量播种机的电气系统设计。同时,综合应用单片机、传感器、步进电机等集成设备,通过对单片机模块、测速模块、步进电机驱动模块及压力采集模块显示模块等进行硬件选型和电路原理设计,利用触摸屏完成对精量播种机的精确控制,从而实现对花生精量播种机的远程控制和实时状态监测。试验结果表明:基于集成电路的花生精量播种机具有较稳定的电气系统,播种精度高、播种间距均匀,可全程对播种过程进行监控,具有较大的推广价值。 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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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
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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