微耕机用旋耕刀组的标准化研究

<正>微耕机零部件已成专业化生产趋势。而对微耕机配套用的旋耕刀组的生产来说,目前还没有相关国家标准可依据,市场上存在各种样式及规格的旋耕刀组,且名称也不统一。因此,规范旋耕刀组型式、尺寸、材料、技术要求和命名方法是当前微耕机产业发展的重要问题。一、微耕机用旋耕刀组的发展现状微耕机产品研发始于上个世纪70年代,在90年代后开始得到较大的发展。由于在旋耕刀组方面进行了创新,可水旱田兼用,     

微耕机旋耕刀辊弯刀排列优化仿真分析

旋耕刀辊弯刀排列是决定微耕机耕作性能的重要因素,本文对微耕机旋耕刀辊进行优化设计并建立其数学模型,研究刀辊各项参数间的影响因素。根据相关文献对一种微耕机旋耕刀辊弯刀进行优化设计,参考旋耕刀辊排列准则建立排列数学模型,得到旋耕刀辊弯刀排列优化设计方法。基于SPH算法建立本文提出的旋耕刀辊弯刀排列方法的刀辊有限元模型,并进行动力学仿真,由仿真结果可知,优化后的旋耕刀辊相对于传统旋耕刀辊在切土时能达到减阻降振、减小冲击和节约能耗的效果。     

基于SPH算法的微耕机旋耕切土仿真研究

运用Pro/E和HYPERMESH软件,建立了旋耕刀辊的有限元模型。通过编辑K文件,建立了土壤SPH模型。应用光滑流体动力学理论,采用MAT147土壤材料,结合DYNA求解器,对微耕机旋耕切土进行了仿真研究。分析了旋耕刀辊切土过程,得到了旋耕刀辊切削力曲线和能量曲线,计算出微耕机在前进速度0.3m/s、旋转速度2.12r/s、耕深110mm、耕宽30mm参数条件下的切土功率为3.45kW,与实际微耕机的使用功率比较接近,验证了仿真的可靠性,可为微耕机整机及其零部件的优化设计提供理论依据。     

微耕机旋耕刀组的分类与选用

针对微耕机旋耕刀组品种多、名称杂且无标准可依的现状,本文就常用的微耕机刀组进行了分类,并为用户提供了选用准则和建议。     

微耕机旋耕刀组的分类与选用

针对微耕机旋耕刀组品种多、名称杂乱且无标准可依的现状,本文就常用的微耕机刀组进行了分类,并为用户提供了选用准则和建议。     

基于SolidWorks Simulation的旋耕刀有限元分析与优化

本文对微耕机的弯形旋耕刀进行了机构分析,建立了旋耕刀的三维模型,基于SolidWorks Simulation有限元分析平台对旋耕刀的应力、位移和应变进行分析。结果表明：在距离刀辊轴最远的刀尖处出现了最大变形量,表面旋耕刀正切刃处的刚度最差,在旋耕刀的刀柄与刀背圆滑过渡连接处出现最大应力集中和最大应变,这与旋耕刀实际工况中产生的刀片弯曲变形或断裂实效的情况一致,验证了有限元分析指导旋耕刀设计生产的可靠性。与此同时,在有限元分析的基础上对旋耕刀结构进行优化设计,采取加厚刀柄和刀背压凹的方式,在不增加刀具质量和现有输出能耗的前提下,大幅度减小了刀具应力集中的产生,从根本上大大减少了刀具断裂频率,延长了刀具使用寿命。     

高原型3Z系列中耕机用旋耕刀设计

云南省农业机械研究所根据多年来对旋耕刀的研究及推广应用,采用经验公式来进行旋耕刀侧切刃曲线的设计计算,设计出适合于中耕机旋耕作业要求的五种规格旋耕刀,满足在云南省多秸秆和绿肥等的粘重土壤田地旋耕作业的农艺要求,同时此种旋耕刀也能够应用于在云南省使用的微耕机和小型手扶拖拉机旋耕机对旋耕刀的使用要求.     

耕耘机旋耕刀的测试数据分析

摘要旋耕刀是耕耘机上的一个重要部件。旋耕刀在使用中磨损量很大，这大多因选取不合适的材质和硬度所致。我们在市场上抽样选择了四种不同材质的旋耕刀作耐磨性试验。部分旋耕刀经过表面淬火和热处理，其刀片外表形成了坚硬的表层。将这些旋耕刀在田间作２０、４０、６０...     

安全使用微耕机 降低事故发生率

微耕机是一种无乘座型的步行操作农业机械，具有重量轻，体积小，结构简单，操作方便，易于维修，工作稳定可靠等特点。常用的工作部件有旋耕机（或旋耕刀辊）、水田轧辊、单铧犁、开沟器等，所以微耕机也常因使用不当或没有注意安全发生伤人事故。     

基于有限元法的微耕机旋耕刀辊切削土壤仿真

旋耕刀辊作为微耕机耕作部件,研究它与土壤相互作用关系,对于提高耕作效率有着重要意义。为此,运用LS-DYNA显式动力学软件,基于有限元方法对微耕机刀辊切削土壤进行了仿真,分析了土壤破碎情况、旋耕刀辊切削力及切削扭矩。结果表明:浅层土壤扰动位移最大、中层土壤次之、深层土壤最小,与实际耕作过程一致;切削过程中旋耕刀的最大切削力为195N,最大扭矩值为21.1N·m,与试验值相吻合,验证了仿真的有效性。研究可为有效揭示土壤耕作机理、优化旋耕刀辊结构及运动参数提供理论依据。     

Overland water and salt flows in a set of rice paddies

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.     

车用发动机润滑油失效规律与更换周期研究

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。     

农村剩余劳动力就业问题的探讨

论述了我国农村剩余劳动力就业的意义,并针对我国农村剩余劳动力的现状,提出多渠道促进农村剩余劳动力就业的途径和办法。     

乡（镇）农业技术推广体系存在的问题及对策

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。     

草莓的采收与贮藏

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。     

金谷子耐旱TG118引种试种及推广应用

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。     

对《种子法》存在问题的探讨

《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。     

瓦房店市水果生产标准化发展研究

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。     

和谐社会理论建设的几点哲学思考

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。     

Review of the Egyptian experience in implementing land drainage projects

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.