共查询到20条相似文献，搜索用时 62 毫秒
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对自行设计的饲草压捆机拨杆联动分捆机构的工作原理作了阐述，建立了杠杆组与压缩机构运动关系。为缩短落板时间，保证分隔板与压缩活塞运动不干涉，设计了弹射式插板，并对其运动规律进行了推导。采用Matlab／Sireulink进行了编程仿真，得出影响落板时间的主要因素，据此改进了结构设计，提高了设计的可靠性。通过实践验证，分捆机构工作良好。 相似文献
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粳稻定向排种装置种子分离机构仿真分析 总被引：1，自引：0，他引：1
为进一步提高超级稻精密育秧播种精度,设计开发了一种定向排种装置,建立了单粒种子分离机构的数学模型,并用Visual Basic6.0语言编写了该机构的辅助分析和仿真程序。同时,分析了主要参数对该机构运动轨迹的姿态和位移的影响:五杆机构中的曲柄长度l1对分离板运动轨迹的姿态无影响,但对分离板在x轴和y轴方向的位移有较大影响;连杆长度l2和摇杆长度l3不仅对分离板运动轨迹的形状和姿态影响较大,而且对分离板在x轴和y轴方向的位移也有较大影响;支架安装角θ1、输出杆长度l5及其与连杆的夹角θ3对分离板运动轨迹的形状影响较小,但对分离板运动轨迹的姿态和在x轴和y轴方向的位移均有较大影响。根据参数影响分析结果,以分离板运动的设计轨迹为优化目标,通过人机交互方式对该机构进行了运动仿真,得到了一组较优机构参数。利用Adams软件对优选后的机构进行了运动学仿真,其输出点轨迹、速度和加速度满足设计要求。仿真结果可为北方粳稻植生带育秧设备定向排种装置的设计提供理论依据。 相似文献
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本文在叶片式立置分离滚筒内质点运动的力学-数学模型的基础上,利用可描述质点在滚筒内运动全过程的计算机数值模拟模型上机进行了模拟试验,研究了质点在滚筒内的运动规律,讨论了滚筒的结构参数和运动参数对质点运动规律的影响。在此基础上,对籽粒从栅格凹板孔中分离的过程进行了理论分析,导出了籽粒从栅格凹板孔中分离的概率计算式,并上机进行了滚筒分离性能的计算机模拟试验。最后对计算机计算和模拟试验的部分结果进行了高速摄影观察验证。 相似文献
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介绍了一种对汽车发动机盖内外板进行包边的包边模结构,针对模具工作时的运动过程及其预弯机构的特点做了简要阐述,并给出了包边凸模在设计过程中的注意事项。 相似文献
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双动刀往复式切割器驱动装置设计 总被引：1，自引：0，他引：1
设计了全喂入稻麦联合收割机双动刀往复式切割器驱动装置.结果表明,利用双层联动摇杆机构可缩小位于收割台外侧的驱动机构宽度,不影响联合收割机下田作业时开道;利用杠杆支点两端运动方向相反的力学原理,可带动上下动刀做反方向同步运动;通过机构综合求得的联动杆尺寸可使上下动刀驱动销获得绝对值相等的运动速度,可满足双动刀往复式切割器实现方向相反、速度相等的切割运动. 相似文献
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研究设计了往复式切割器新型驱动装置,用于全喂入稻麦联合收割机双动刀切割器.研究表明,利用双层联动摇杆机构可减少位于收割外侧的驱动机构宽度,不影响联合收割机下田作业时开道;利用杠杆支点两端运动方向相反的力学原理,可带动上下动刀做反方向同步运动;通过机构综合确定联动杆尺寸,可使上下动刀驱动销获得绝对值相等的运动速度,从而保证了双动刀往复式切割器实现方向相反、速度相等的切割运动. 相似文献
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Overland water and salt flows in a set of rice paddies 总被引：1，自引：0，他引：1
E. Playn O. Prez-Coveta A. Martínez-Cob J. Herrero P. García-Navarro B. Latorre P. Brufau J. Garcs 《Agricultural Water Management》2008,95(6):645-658
Cultivation of paddy rice in semiarid areas of the world faces problems related to water scarcity. This paper aims at characterizing water use in a set of paddies located in the central Ebro basin of Spain using experimentation and computer simulation. A commercial field with six interconnected paddies, with a total area of 5.31 ha, was instrumented to measure discharge and water quality at the inflow and at the runoff outlet. The soil was classified as a Typic Calcixerept, and was characterized by a mild salinity (2.5 dS m−1) and an infiltration rate of 5.8 mm day−1. The evolution of flow depth at all paddies was recorded. Data from the 2002 rice-growing season was elaborated using a mass balance approach to estimate the infiltration rate and the evolution of discharge between paddies. Seasonal crop evapotranspiration, estimated with the surface renewal method, was 731 mm (5.1 mm day−1), very similar to that of other summer cereals grown in the area, like corn. The irrigation input was 1874 mm, deep percolation was 830 mm and surface runoff was 372 mm. Irrigation efficiency was estimated as 41%. The quality of surface runoff water was slightly degraded due to evapoconcentration and to the contact with the soil. During the period 2001–2003, the electrical conductivity of surface runoff water was 54% higher than that of irrigation water. However, the runoff water was suitable for irrigation. A mechanistic mass balance model of inter-paddy water flow permitted to conclude that improvements in irrigation efficiency cannot be easily obtained in the experimental conditions. Since deep percolation losses more than double surface runoff losses, a reduction in irrigation discharge would not have much room for efficiency improvement. Simulations also showed that rice irrigation performance was not negatively affected by the fluctuating inflow hydrograph. These hydrographs are typical of turnouts located at the tail end of tertiary irrigation ditches. In fact, these are the sites where rice has been historically cultivated in the study area, since local soils are often saline-sodic and can only grow paddy rice taking advantage of the low salinity of the irrigation water. The low infiltration rate characteristic of these saline-sodic soils (an experimental value of 3.2 mm day−1 was obtained) combined with a reduced irrigation discharge resulted in a simulated irrigation efficiency of 60%. Paddy rice irrigation efficiency can attain reasonable values in the local saline-sodic soils, where the infiltration rate is clearly smaller than the average daily rice evapotranspiration. 相似文献
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车用发动机润滑油失效规律与更换周期研究 总被引：7，自引：0，他引：7
研究在正常使用条件下１０Ｗ／３０－ＱＣ级润滑油用于某型车用发动机时所表现的失效规律,确认期服从两参数Ｗｅｉｂｕｌｌ分布,并给出分布的尺度参数η和形状参数ｍ之最佳线性无偏估计（ＢＬＵＥ）同时,还为定量分析,计算车用发动机润滑油的使用可靠性和合理确定其更换周期提供了一套可供借鉴的方法,并给出了具体的计算实例。 相似文献
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瓦房店市是我国重要的水果生产基地,在国内水果生产领域占有重要地位。随着水果市场化的不断深入,如何满足和适应国内外市场需求成为瓦房店市水果生产的关键问题。从瓦房店市水果生产实际出发,阐述了实施水果生产标准化的必要性,提出了发展水果生产标准化的具体措施。 相似文献
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对引进的谷子新品种金谷子耐旱TG118进行品种比较试验和多点试种。结果表明：该品种抗旱、耐瘠、适应性强,稳产、高产、抗病抗风抗倒伏强,品质优良,粮草兼用,种植简单,省工易管;一般产量在6000kg/hm2以上,比当地主栽品种增产20%以上。最高产量达9450kg/hm2,适于在辽西北地区推广应用。 相似文献
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对《种子法》存在问题的探讨 总被引：1，自引：0，他引：1
李鹏 《农业机械化与电气化》2011,(6):129-130
《种子法》是我国种植业第一部法律。自实施以来,为依法加强种子管理提供了有力的法律支撑,促进我国种子产业发生翻天覆地的变化。但随着依法管理工作的深入和种子产业的快速发展,《种子法》及配套规章的一些问题逐步显现出来。对《种子法》及配套规章存在的问题进行深入分析,对需要进一步补充的章节以及需要调整的内容进行深入探讨,以求更加完善和明确。 相似文献
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赵国杰 《农业机械化与电气化》2011,(4):106-107
乡（镇）农技推广体系是农业发展的关键。介绍朝阳市农业技术推广体系的现状,针对目前体制及运行机制、服务手段等方面存在的问题,提出适合朝阳市乡（镇）农技推广体系改革与发展的对策,以期对全省农技推广体系改革和发展起到一些借鉴作用。 相似文献
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苑庆刚 《农业机械化与电气化》2010,(3):52-54
草莓果味酸甜爽口,营养价值高,为人们所喜爱的应市鲜果之一。由于草莓易受损伤和微生物侵染,因此其采收、贮藏过程极为重要。介绍草莓采收过程中的注意事项以及11种贮藏保鲜技术的实施步骤和操作方法,推介9种加工方式,为草莓产业化提供技术支持。 相似文献
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在新世纪,面对机遇和挑战,党的十六大把“社会更加和谐”作为全面建设更高水平的小康社会的一个重要目标。中国人素有社会和谐的理想;西方人自古也向往社会和谐;借鉴东西方两种和谐社会思想的经验、教训,构建社会主义和谐社会理论。 相似文献
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About 30 years have passed since the Government of Egypt embarked on implementing a series of large scale drainage projects. At present, about 3.8 million acres have been provided with drainage systems on the basis of systematic pre-drainage investigations and designs. The target is to provide drains in approximately 6.4 million acres in the Nile Valley and Delta.The implementation of the subsurface drainage system is carried out by the public sector and private contractors under direct supervision of governmental regional departments. The implementation process depends on many factors related to the drainage material, machinery, manpower, site requirements, farmers and organizations involved. Problems and constraints are sometimes challenging, however, the annual rate of implementation has gradually increased to 170,000 acre/year.This paper discusses the different aspects involved in the implementation process of drainage systems. The development in materials, machinery and construction technologies will be reviewed. Institutional and management factors are going to be also considered. 相似文献