巧用Excel实现农网工程材料自动生成

1 主要函数解释 (1)IF:判断一个条件是否满足,如果满足返回一个值,如果不满足返回另一个值.     

农业节水措施对地下水涵养的作用及其敏感性分析

以北京市大兴区为研究区,利用经校验的水平衡模型,通过调整灌溉满足率和灌溉水利用系数,探讨了不同农业节水措施对增加地下水补给量和减少地下水开采量的作用及其敏感性。结果表明,不同水文年型下,降低灌溉满足率及提高灌溉水利用系数都能减少地下水开采量,且降低灌溉满足率对减少地下净开采量的作用更为显著,有利于区域地下水涵养。在参数取值范围内,地下水净开采量对灌溉满足率的敏感性较大,而地下水补给量对灌溉水利用系数的敏感性较高。与提高灌溉水利用系数相比,对资源性缺水区域,采用先进节水技术,适度降低区域灌溉满足率,对促进水资源持续有效利用及加大地下水涵养具有更显著的效果。     

用结构钢焊条焊接铸铁的研究

通过用结构钢焊条补焊铸铁,总结了一套既能满足工件使用性能要求,又可以满足焊接条件要求的技术方案,还降低了生产成本。     

一种新型消防分水器的结构设计

现在市场上的消防分水器以中低压为主,以不能满足社会发展的需要。文章研究在基于3.75MPa高压下的新型消防分水器的结构设计,以期满足社会的需求。     

长洲水利枢纽AGC入网测试方法

水电厂自动发电控制(AGC)作为频率二次调整,是按照预定的条件和要求,以迅速、经济的方式自动控制水电厂有功功率来满足电力系统的需要。自动发电控制的执行依赖于发电机组对控制指令的响应。文章详细介绍广西某水电站AGC入网前测试要求及步骤。通过测试后,电站的AGC功能满足入网的要求,满足电站机组经济优化运行、提高电网稳定水平和电能质量的要求。     

浅谈配电网无功补偿方式

1 无功补偿的原则 1.1 总体平衡与局部平衡相结合,既要满足全网的总无功平衡,又要满足分线、分站的无功平衡.     

汽车电子节气门控制系统建模与仿真

电控燃油喷射系统无法满足汽车运行所有工况下的理想要求。为此,笔者在汽车电子节气门控制系统结构基础上,对该系统模型及控制器设计进行探讨。实践证明,汽车电子节气门控制满足预期效果。     

挥发雾化式燃油加热器雾化系统积碳问题的研究

汽车燃油加热器雾化系统是燃烧器的关键装置,工程设计上需要有足够的雾化能力来满足燃烧功率,同时还需避免产生大量积碳,以满足加热器长期使用和免维护的要求。本文通过仿真燃烧器进气射流速度场和静压场,从燃烧器稳焰燃烧原理的角度,分析了雾化装置产生积碳的机理,并通过试验给出了满足工程应用的数据,对燃烧器雾化装置的设计具有一定的参考价值。     

物联网科研教学实验平台在农业院校中的应用

物联网科研教学实验平台能够满足农林专业、环境专业对物联网技术的应用,满足农业应用系统设计等课程的实践实训教学需要,并为学生或教师的物联网创新应用项目开发提供平台。     

基于混合体系结构的无人驾驶车辆系统

从无人驾驶车辆系统的自主性、实时性、适应性要求出发,建立了基于功能和行为相结合的无人驾驶车辆混合式体系结构,基于功能的分解结构满足无人驾驶车辆的自主控制要求,基于行为的分解结构则满足由于行车环境复杂性以及多变性带来的对无人驾驶车辆车系统局部路径规划要求的反应能力和适应能力。实验结果表明,基于混合式体系结构的无人驾驶车辆系统具有自主性,且在环境发生变化时满足实时性及适应性要求。     

滇东北作物耗水特性及影响因素

基于滇东北地区3个气象站点(会泽站、昭通站、沾益站)1955-2013年逐日气象资料,采用FAO-56 Penman-Monteith公式,计算并分析滇东北地区水稻、春玉米和冬小麦全生育期需水量及其变化趋势,同时采用偏相关分析和逐步回归分析探讨各气象因子对主要粮食作物需水量影响的程度.结果表明:昭通站主要粮食作物需水量随时间呈不同程度减少,每10 a水稻需水量减少10.07 mm,春玉米减少1.44 mm,冬小麦减少1.06 mm.而其他站点呈增加趋势,水稻需水量每10 a分别增加8.85,4.48 mm,春玉米分别增加8.38,4.57 mm,冬小麦分别增加7.39,3.10 mm.3个站点同一种作物各生育阶段需水量规律基本一致,水稻各生育期需水量从大到小依次为:分蘖,拔节,抽穗,乳熟,黄熟,返青;玉米的依次为:拔节,灌浆,苗期,孕穗,成熟;小麦的的依次为:乳熟,开花,成熟,苗期.日照和平均风速是影响水稻和玉米需水量最主要的气象因子,且呈显著正相关关系,就各站点而言,影响冬小麦需水量的气象因子存在差异,其中会泽站和沾益站同日照时数和平均气温呈显著正相关,而昭通站与平均湿度呈显著负相关,同日照时数呈显著正相关关系.     

A statistical approach for estimating irrigation water usage in western Saudi Arabia

This paper presents a statistical practical approach to the estimation of irrigation water requirement in the western region of Saudi Arabia. The approach describes the variation in water requirements as a function of regional climatic parameters, types of crop grown and irrigation techniques used. Irrigation water requirements are also calculated, for comparison purposes, by Modified Penman and Blaney-Criddle methods, taking leaching requirements and losses into consideration. It is found that irrigation water requirements for vegetables and perennial crops are close to the values estimated by Blaney-Criddle method, while for fodder and cereal they are close to the values estimated by Modified Penman Method.     

Planning intraseasonal water requirements in irrigation projects

The problem of planning intraseasonal irrigation requirements for the reservoir based projects with an extensive water distribution network is addressed. The network is hierarchical and consists of canals, distributaries or laterals and field turnouts or outlets. Irrigation requirements are estimated by considering the problem at two levels. At the first level, the intraseasonal weekly and biweekly irrigation requirements of crops at the field turnouts are estimated by a daily two layer soil water balance model. At the second level, the field level water requirements are transferred to the upstream nodes of the water distribution network after accounting for conveyance losses by a simple hydraulic model for flow in canals. The main questions examined are (i) whether there are significant year to year fluctuations in intraseasonal field level irrigation requirements of crops and (ii) whether a reliable sequence of target weekly/biweekly reservoir releases can be derived for irrigation planning at the project level. This is done in the context of a case study irrigation project in India.     

“国才考试”视域下农业工程专业英语就业要求调查——由英语口语和英语写作谈起

教育国际化给各行各业带来新的机遇和挑战,尤其对农业工程专业学生的英语口语表达和英语书面写作方面产生了较大的冲击。过硬的英语口语表达和英语书面写作能力是农业工程专业学生不可或缺的能力,这两种能力在毕业生的就业竞争力上也举足轻重。从农业工程专业学生英语口语表达和英语书面写作的就业要求出发,对农业工程专业学生英语就业要求进行了调查,探讨提高农业工程专业毕业生就业竞争力的方法,以及如何更好地满足英语就业要求,提高就业竞争力。      

Leaching requirement for salinity control I. Wheat,sorghum, and lettuce

Crop productivity and water use efficiency when saline irrigation water is used are highest when efficient irrigation systems are managed to meet the crop's leaching requirement. The objective of this experiment was to establish the leaching requirement. The objective of this experiment was to establish the leaching requirements for frequently irrigated wheat, grain sorghum, and head lettuce. The 4-year study in field plots consisted of six replicated leaching fraction treatments. The plots were pulse-irrigated daily with water having a total dissolved salts concentration of 1350 mg/l.The leaching requirements are 0.08 for wheat and sorghum, and 0.26 for lettuce. The respective evapotranspiration during each crop's growing season coincident with the leaching requirements was 440, 550, and 245 mm. A pan factor of 0.7 was consistent among these three crops at their respective leaching requirements. With daily irrigation, 90% of the crop's water uptake occurred above a soil depth of 0.6 m, independent of leaching fraction.     

基于FWAY网络的水厂滤站PL自

结合某水厂滤站的工艺及要求，介绍了基于FIPWAY网络的PLC自动化改造的特点及实现。系统设计了新颖的数据结构，选择了可靠的通讯结构，为复杂工艺要求提供了成功的解决方案。     

一种快速夹紧装置的设计

传统螺纹夹紧机构每转1圈,钳口位置只移动1个螺距,夹持速度慢,效率低。针对这些问题设计了一种全新结构的快速夹紧机构,能够完成工件的快速装夹和拆卸。该夹紧机构结构简单、受力均衡、整体刚度强度高、成本低,具有重要的实际应用价值。     

Determination of spatial water requirements at county and regional levels using crop models and GIS: An example for the State of Parana,Brazil

Due to the competitive use of available water resources, it has become important to define appropriate strategies for planning and management of irrigated farmland. To achieve effective planning, accurate information is needed for crop water use requirements, irrigation withdrawals, runoff and nitrate leaching as a function of crop, soil type and weather conditions at a regional level. Interfacing crop models with a geographic information system (GIS) extends the capabilities of the crop models to a regional level. The objective of this study was to determine the irrigation requirements, annual runoff and annual nitrate leaching for the most important crops of the Tibagi river basin in the State of Parana, Brazil. The computer tool selected for this study was the Decision Support System for Agrotechnology Transfer (DSSAT) version 3.5 (98.0) and its associated crop modeling and spatial application system AEGIS/WIN. It was assumed that farms within the same county use similar management practices. To achieve representative estimates of irrigation requirements, the weather data from stations located within each county or the nearest weather station were used. A weighting factor based on the proportion of soil type and crop acreage was applied to determine total annual irrigation withdrawals, annual runoff and nitrate leaching for each county in the river basin. The model predicted outputs, including yield, irrigation requirements, runoff and nitrate leached for different soil types in each county, were analyzed, using spatial analysis methods. This allowed for the display of thematic maps for irrigation requirements, annual runoff and nitrate leaching, and to relate this information with irrigation management and planning. The maximum annual irrigation withdrawal, runoff and nitrate leaching were 22,969 m³ per year, 31,152 m³ per year and 1488 t N per year in the Tibagi river basin. This study showed that crop simulation models linked to GIS can be an effective planning tool to help determine irrigation requirements for river basins and large watersheds.     

《非道路柴油移动机械污染物排放控制技术要求》浅析

《非道路柴油移动机械污染物排放控制技术要求》是《非道路移动机械用柴油机排气污染物排放限值及测量方法（中国第三、四阶段）》（GB 20891—2014）第四阶段的具体技术要求。与第三阶段相比,该标准增加了适用范围,同时技术要求中增加了达标检查、远程监控和车载诊断等要求。为更好理解标准,该文对标准的主要内容进行了阐述与分析,并从技术可行性和成本可行性两方面对标准进行了可行性分析。      

基于有限元法的铰接车摆臂机构改进分析

利用RecurDyn对铰接车进行了动力学仿真,计算出了整车原地转向时车轮连接端的受力。在此基础上,通过三维软件SolidWorks建立了摆臂机构的模型,利用HyperWorks对该机构壳体进行OptiStruct结构有限元分析,得到其各节点的应力应变云图及变形图,发现车辆转向载荷作用下,该外壳结构能达到强度要求而不能达到刚度要求。通过对原结构进行加强与优化,使设计满足铰接车各种工况下强度、刚度要求,为车辆平稳行驶提供保障。