高地隙液压四轮驱动喷雾机转向防滑控制系统

建立了高地隙四轮驱动喷雾机转向过程中的线性2自由度模型,以前轮转向为例计算出了实际转向角,设计了一种以实际转速比与理论转速比差值为控制对象的转向防滑控制系统。构建了转向电液防滑系统试验装置,分别在转角为5°、10°、15°、20°、25°、30°以及转角在0°～30°连续变化时对控制系统进行了试验验证。结果表明,高地隙四轮驱动喷雾机的转向防滑控制效果良好,控制平均误差最大为2.01%,均值为1.25%。     

基于变量马达控制的喷雾机驱动防滑系统设计与试验

高地隙自走式喷雾机因其作业环境复杂易产生车轮滑转,影响静液压驱动系统流量及压力稳定性,严重时导致整机失去通过性能,故须进行防滑控制,保证其具备驱动稳定性和脱困能力。本文提出一种高地隙自走式喷雾机静液压驱动系统防滑控制方法,采用双线性模型定义滑转率与附着系数之间的关系,设计了滑模控制器,并通过田间非道路试验验证了驱动防滑系统的控制性能。试验结果表明,该系统可将喷雾机滑转率控制在0.15以内。在起步加速与匀速工况下,喷雾机滑转率均值为0.020和0.019;在越沟工况下,可2s内实现整机快速脱困。以上结果验证了所设计的喷雾机滑模驱动防滑系统具有良好的防滑性能,能够保证喷雾机在典型工况下平稳行驶,有效减少了地面不利条件对整机行驶稳定性的影响。     

高地隙喷雾机在玉米生产中的应用

阐述了高地隙喷雾机在玉米生产期内病虫草害防治过程中的重要作用,重点介绍了国内外典型高地隙喷雾机产品的技术特点和应用现状,分析了制约国产高地隙喷雾机发展和推广的因素,探讨了国产高地隙喷雾机的发展趋势,指出了国产高地隙喷雾机在地隙、市场需求灵活性方面具有较大优势,市场前景良好,为我国高地隙喷雾机的研发、推广应用提供借鉴和参考。      

农用四轮液压驱动底盘的防滑控制系统总体设计

介绍了高地隙四轮液压驱动底盘的防滑控制系统的总体结构.该控制系统能够实时监控底盘行使状态,通过实时获取的角位移和转速信号自动识别是否发生打滑,并利用FUZZ-PID算法实现打滑判断和调控.应用该控制系统对四轮驱动底盘的液压调速系统进行实验,结果表明:该控制系统能及时判断车轮的打滑,并使车轮间的滑转率长时间保持在0.01～0.05之间,有效地保证了车辆的稳定运行.     

自走式玉米高地隙喷雾机底盘系统设计研究

玉米生长中后期常规施药机械难以适应,高地隙喷雾机的研制问题亟待解决。自走式高地隙底盘技术是玉米高地隙喷雾机研制的核心问题。为此,根据玉米生长中后期植保作业要求,制定了喷雾机总体设计方案;结合自走式底盘技术原理,应用solidworks对喷雾机底盘系统相关的行走系、转向系、制动系、轮距调整系及喷杆系等关键系统进行了三维设计,为底盘系统动力学建模、性能仿真分析及自走式玉米高地隙喷雾机的研制奠定了基础。     

高地隙喷杆喷雾机发展现状与应用普及趋势分析

随着我国农业机械化水平不断提高，应用与普及适合于高秆农作物病虫害防治的农业植保机械是解决高秆类作物中后期施药难、施药效果差的重要发展趋势。通过高地隙喷杆喷雾机的国内外发展现状，提出了高地隙喷杆喷雾机发展的必要性，分析了高地隙喷杆喷雾机应用普及趋势，对应用普及高地隙喷杆喷雾机，促进高地隙植保机械发展具有一定的参考。     

风幕式高地隙喷杆喷雾机研究与设计

针对传统喷杆喷雾机底盘较低不能满足玉米中后期植保作业,以及雾滴飘失、农药利用率低等问题,研制了高地隙底盘与风幕式防飘技术相结合的风幕式高地隙喷杆喷雾机。整机主要由驾驶室组件、高地隙静液压底盘、喷杆架组件、喷雾系统和风幕系统等组成,高地隙底盘采用静液压驱动底盘,四轮驱动,四轮转向,龙门式机架最小离地间隙为2 600mm,轮距调节范围为2 280 3 300mm。试验结果表明:有辅助气流较无辅助气流雾滴在玉米整个冠层平均覆盖率提高了57.37%,风幕系统对于增加雾滴在玉米冠层沉积及减少雾滴飘失作用明显。该机具底盘离地间隙高、防飘性能好,可以满足玉米中后期病虫害防治要求。     

高地隙自走式喷杆喷雾机研究现状及展望

高地隙自走式喷杆喷雾机作为一种重要的植保机械,具有工作效率高、生产成本较低以及工作稳定等优点,在国内外得到广泛应用,我国对高地隙自走式喷杆喷雾机关键技术也进行了研究.本文综述了国内外高地隙自走式喷杆喷雾机的研究与应用现状,讨论了当前面临的一些问题与不足,并对其发展趋势进行了探讨.     

自走式高地隙喷杆喷雾机防治效果试验分析

对3WPG-600自走式高地隙喷杆喷雾机防治小麦赤霉病和白粉病的效果进行了测试,并与HH-14型背负式机动喷雾机进行对比。试验结果表明,与背负式机动喷雾机相比,3WPG-600自走式高地隙喷杆喷雾机的雾滴覆盖率明显提高,而且对防治小麦赤霉病和白粉病的效果更好。     

大田蔬菜高地隙自走式喷杆喷雾机的研制

针对我国缺乏大田蔬菜地高效施药机具的现状,研制出一种小型、高效、安全的防治大田蔬菜与水稻病虫草害的轻便型自走式高地隙喷杆喷雾机。该机具集成高地隙自走式底盘、喷雾系统、机电液中央控制系统,自走式底盘主要由机架、动力系统、行走转向系统以及液压系统几个方面组成。该机具四轮驱动、四轮转向、行驶稳定、转向灵活、适应性强,喷杆前置、药箱后置,保证了整机重心平衡,采用电动推杆实现喷杆的折叠,减轻了喷杆质量,作业效率高,不仅满足大田蔬菜施药农艺要求,还可应用于水田施药作业。     

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.     

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。     

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。     

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.     

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。     

A European irrigation map for spatially distributed agricultural modelling

We present a pan-European irrigation map based on regional European statistics, a European land use map and a global irrigation map. The map provides spatial information on the distribution of irrigated areas per crop type which allows determining irrigated areas at the level of spatial modelling units. The map is a requirement for a European scale assessment of the impacts of irrigated agriculture on water resources based on spatially distributed modelling of crop growth and water balance. The irrigation map was compiled in a two step procedure. First, irrigated areas were distributed to potentially irrigated crops at a regional level (European statistical regions NUTS3), combining Farm Structure Survey (FSS) data on irrigated area, crop-specific irrigated area for crops whenever available, and total crop area. Second, crop-specific irrigated area was distributed within each statistical region based on the crop distribution given in our land use map. A global map of irrigated areas with a 5′ resolution was used to further constrain the distribution within each NUTS3 based on the density of irrigated areas. The constrained distribution of irrigated areas as taken from statistics to a high resolution dataset enables us to estimate irrigated areas for various spatial entities, including administrative, natural and artificial units, providing a reasonable input scenario for large-scale distributed modelling applications. The dataset bridges a gap between global datasets and detailed regional data on the distribution of irrigated areas and provides information for various assessments and modelling applications.     

粉质仪和拉伸仪在面粉生产中的应用

在介绍粉质仪和拉伸仪结构和原理的基础上,探讨了粉质曲线中吸水率、形成时间、稳定时间、弱化度和评价值等指标与面粉品质的关系,以及如何根据拉伸曲线中面团最大拉伸阻力、延伸度和拉伸曲线面积等指标来评价面团品质,并结合生产实际,概述了粉质仪和拉伸仪在面粉生产中的作用。     

农村信息化服务的现状及建设措施

分析当前我国农村信息化服务的现状,提出加强农村信息化服务的新举措。     

车辆ABS控制算法的研究及探讨

对现代汽车的ABS控制算法作了一些简单的介绍,同时指出了它们的一些缺陷,相应地提出了几种对ABS的其它控制方法并加以探讨,其中着重论述了ABS门限值控制算法中参考车速的确定方法和基于附着系数的控制算法。