基于PLC的农作物喷灌控制系统设计

首先分析了农作物喷灌控制系统的现状,利用三菱FX2N 的 PLC作为控制设备,用其自带的PID功能指令及其扩展功能模块FX2N-4AD实现了系统对农作物喷灌的自动控制.该系统将提高水资源利用率,并为我国尽早实现农业现代化做出贡献.     

农田喷灌车虚拟仿真设计

选取农田喷灌车为研究对象,使用Pro/E对喷灌车进行机械三维基础建模,利用3ds Max对模型进行后期处理,包括模型顶点和面的处理、添加材质、机具命名、轴心调整等。在Unity3D建立虚拟场景,对喷灌车的各个部件按照仿真需要进行父子关系的处理,并建立辅助仿真对象。通过分析喷灌车运动原理,建立相应的数学模型,并在此基础上对喷灌车的行驶与机械臂的展开与折叠进行虚拟仿真。通过对利用父子关系加旋转运动的有机结合,实现了农机复杂运动仿真的通用方法,可以推广到各种农机具的虚拟仿真展示中。     

喷头水星分布仿真及组合优化软件系统研究

喷灌以其适应性广、易于机械化作业等优点成为目前世界上广泛采用的节水灌溉技术之一.喷灌均匀度是衡量灌溉质量和喷头水力性能的重要指标,是喷灌系统规划设计中的重要参数.通过接口软件MATCOME4.5,结合MATLAB与VisualC++工具混合开发出喷头水量分布仿真及组合优化软件系统.该系统操作简单,功能强大,能够脱离混合开发环境独立运行.用户只需输入雨量筒实测数据,选择喷头组合方式,插值方法及插值间距等指令,系统即可快速得出基于给定组合方式下的多种喷灌均匀度系数,喷洒水量分布图,或以某种均匀度系数为评价指标的喷头组合间距优化结果.系统给喷灌质量或喷头性能的评价分析工作以及喷灌系统的规划设计工作带来了极大便利.     

桑田灌溉中的喷灌技术研究

根据桑田的特点,结合节水灌溉的要求,采用PLC电气控制原理结合电磁阀自动切换,实现了无人管理和定时、定点、定量灌溉,同时从技术和经济两方面阐述了桑田喷灌系统的布施方法。桑田喷灌技术的研究对于与之相似的喷灌系统的设计有很大的参考价值。     

一种脚踏微型喷灌泵的设计

分析了当前农作物浇灌主要的方法,指出了种植于山坡、丘陵地区及小地块受旱农作物补水存在的困难和问题.通过将齿轮齿条传动机构与水泵工作机构地连接在一起、以人的脚踏力作为动力、由泵体中的柱塞对水挤压而获得具有一定冲力和射程的水流的工作原理,设计出一种脚踏微型喷灌泵.该喷灌泵不用电、不用油,操作简单、携带方便.与单纯人工相比,能够数倍提高山坡、丘陵地区及小地块受旱农作物喷灌补水的工作效率.     

草坪喷灌系统规划设计与施工应注意的问题

草坪喷灌不但节水、提高草坪质量,另外还增加国林景观效果,因而逐渐受到园林界的青睐。设计安装一套高质量的草坪喷灌系统,应主要注意如下几个问题：①重视过滤系统;②现场勘测不可省略;③充分了解喷头的性能及最佳工作条件;④采用PVC管材及埋藏式喷头是现代园林喷灌的趋势。     

允许喷灌强度及每次喷灌时间的确定

本文利用水文学中产流的基本原理,建立了喷灌强度及每次喷灌时间的计算模型。提出了允许喷灌强度可以大于目前多采用的稳定入渗速率的观点,从而可缩短喷灌所需时间,更好地发挥喷灌省水、省工的优点,为喷灌系统的设计提供依据。     

喷灌条件下土壤水分入渗的数学模拟

采用摇臂式喷头喷灌时,地表处于蒸发和入渗的交替变化过程。在室内模拟了单喷头喷洒时土壤水分的运移过程。试验结果显示,当上边界条件同时考虑蒸发和喷灌时,模拟的土壤水分分布与用平均喷灌强度模拟的结果相比更接近于实测的土壤水分,但是2种情况模拟的土壤水分分布区域一致。水量平衡计算显示,随着喷灌时间的增加,2种方法模拟的土壤含水量相差较小,逐渐接近实测值。     

喷灌技术特征与喷灌机的使用

喷灌是采用喷灌机将压力水喷射到低空,经雾化后像雨滴一样均匀地降落到作物和地表面.喷灌的用途很多,主要用于农作物、林业苗圃、牧业草场、蔬菜果树、经济作物,园林草皮、花卉等.     

基于开环控制的变量喷头组合喷灌试验

构建了基于开环控制策略的方形域喷灌系统,以喷头转速一致为评价指标,采用逐级计算方法对管路进行水力计算,以优化方形域喷头组合喷灌配置模式。试验研究了单喷头的水力性能,依据单喷头水量分布对喷头组合喷灌均匀性进行了仿真。通过与2喷头组合喷灌试验对比获得以下结论:在实验室条件下对方形域喷头进行仿真计算获得的均匀度数据与组合试验结果基本一致,因此可通过仿真试验研究变量喷头组合喷灌均匀性;基于S800喷头的方形域组合喷灌,其平均喷灌强度为2.8mm/h,组合喷灌均匀度达77%,达到《喷灌工程技术规范》规定的定喷系统均匀系数不低于75%的要求。     

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。