共查询到20条相似文献,搜索用时 93 毫秒
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利用高速摄影技术对气力有序抛秧钵体苗的运动状态进行了试验分析,获得了钵体苗吹出至与导苗管壁碰撞以及钵体苗在导苗管中下落过程的运动状态和时间,为抛秧设备的进一步完善提供了依据。 相似文献
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钵体苗吹出是气力有序抛秧一个主要的环节。为此,运用ANSYS/LS-DYNA软件对钵体苗吹出过程进行了有限元模拟分析,通过对其分析计算,得出了位移、应力和应变等结果云图,以及相应的应力时间关系曲线,为气力有序抛栽提供理论依据。 相似文献
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通过对2SP—10型水稻机制钵苗抛秧机自动排序机构中钵苗的运动轨迹、速度、加速度,以及定量抛秧机构中限位挡铁前端面与抛秧爪工作面之间最小夹角进行的理论分析和试验研究,优化了有关参数,提出了改进方案。 相似文献
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为了适应水稻钵苗移栽高产栽培技术的种植模式,综合插秧有序与抛秧浅栽的特点,研制了一种伞自动钵苗有序浅植机,实现了钵育秧苗间歇、有序、准确、可靠供给与浅栽。 相似文献
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提高水稻钵苗机械行抛质量浅析 总被引:1,自引:0,他引:1
水稻抛秧栽培技术是一项新的水稻育苗移栽技术。它将传统的育秧方式改为软塑穴盘育秧,是农艺的一项改革。为提高其机械化水平,各地相继开发了多种专用摆栽机械。中国农业大学研制的2ZPY-H530型水稻钵体苗行抛机,解决了水稻钵体苗有序抛秧的技术难点。该机的最大特点是采用了“同步输秧和周向交错对辊式拔苗装置”和防壅泥、壅水式“深波浪拖板”。拔苗装置可实现软塑育秧穴盘的连续自动输秧、拔秧,由分行栽植部件完成秧苗等距成行有序栽植,对秧盘损失小。1-对盘育秧和秧苗的要求(1)机械播种。水稻抛秧要求采用专用穴盘育… 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