30挤出机PLC温度控制系统浅析

介绍了以可编程序控制器为核心、采用比例积分微分算法和脉宽调制原理的挤出机温度控制系统,系统以西门子公司的S72300可编程序控制器为核心,完成温度的采集及自动调节.本温控系统硬件简单、控温精度高、性能稳定,具有较高的实用价值.     

无源蓄冷控温运输箱设计与试验

针对蓄冷运输箱信息化程度低、控温时间短、控温困难等问题,设计了一款集控温、远程监控、定位、故障诊断等功能于一体的蓄冷运输箱。以脐橙为试验对象,结合能耗模型,对蓄冷控温箱控温性能进行了研究。结果表明,箱内各截面温度不均匀系数分别为0.38、0.47、0.78,温度极差最大值为2.8℃,均匀性较好;当蓄冷剂用量为180 kg,预冷脐橙660 kg,在外部环境平均温度26.39℃的条件下,总控温时长为122 h,风机共执行控温21次,且随着蓄冷量减少,风机开启控温所用时间呈指数上升趋势,决定系数不小于0.928 0;结合能耗模型分析得出,该箱体在广州夏季高温环境下可控温5 d以上,能够满足远距离运输要求。     

汾河兰村—二坝流域径流模拟及气候变化对径流影响研究

以汾河兰村—二坝区间流域为研究对象,建立研究区SWAT分布式径流模拟模型,并利用SWAT-CUP程序SUFI-2算法进行模型敏感性分析及参数率定,进一步将率定好的模型应用于气候变化条件下的径流响应分析,为区域水资源管理决策提供理论依据与技术支持。径流模拟结果表明:模拟期的各项精度评价指标均达到乙级,SWAT模型在研究区径流模拟的适用性较好。气候变化条件下径流响应分析表明:径流变化与温度变化呈负相关,且随着温度变幅的增加,径流减小速率减缓,温度影响效应减弱;径流变化与降雨变化呈正相关,且随着降雨变幅的增加,径流量增加速率加大,降雨影响效应加强;相同的径流响应,气温与降雨的变化基本呈线性变化关系,即气温增加0.5℃的径流效应与降雨平均减少0.49%(变化幅度0.38%~0.67%)的径流效应等效。     

盛涨牌CSZ6CCB-8001B型名茶炒制机

浙江新昌县盛涨机械厂(电话:0575-6886019)研制成功盛涨牌CSZ6CCB8001B型名茶炒制机。该炒制机是在传统手工炒制工艺的基础上,经过反复试制改进而研制的新一代茶机,具有性能好,牢固耐用,操作简便安全等特点。该炒茶机采用自动控温装置和特殊隔热技术,锅底温度均匀、省电,并设置炒板位置调节机构。炒制出来的龙井扁形茶色泽绿翠,香味醇爽,扁平光滑,芽叶完整。该炒茶机已获“浙江省农业厅农机推广鉴定证书”。该机主要技术参数如下。电源电压:220V功率:电机0.75kW电热板4.4kW加热温度:120～200℃青叶投量:每锅0.3～0.4kg生产率:0.4～0.6kg…     

基于1D CNN-GRU的日光温室温度预测模型研究

准确预测日光温室温度是实现温室高效调控的关键,对作物生长发育具有重要意义,但因温度具有时序性、非线性及多耦合性等特征,难以实现连续、精准、长时化预测。提出了一种基于1D CNN-GRU(One dimensional convolutional neural networks-gated recurrent unit)的日光温室温度预测模型,通过温室内外监测平台获取内外环境因子,以斯皮尔曼相关系数获取相关性强特征,构造特征与时间步长的二维矩阵输入网络进行温度预测,模型在测试集上预测1～4 h后的决定系数为0.970～0.994,均方根误差为0.612～1.358℃,平均绝对误差为0.428～0.854℃,绝对值的最大绝对误差为0.856～1.959℃。并在不同清晰度指数K_T下进行验证,结果表明,模型在K_T≥0.5(晴)时预测效果最好,且在其他K_T下模型相对误差在10%以内,可以达到温室生产所需的预测精度要求,为日光温室精准高效控温提供了重要依据。     

种子催芽机

吉峰牌种子催芽机具有自动控温、自动报警和自动供水功能,为种子萌发创造最佳温度、水分和氧气条件,提高种苗活力和抗病力,适用于粮、棉、油、菜、花、果、树、药、烟等各类种子催芽育苗和发芽率测试,亦可用于无公害芽苗菜生产和特种养殖。该产品经专家鉴定,达国内先进水平,与水稻旱育秧、抛秧、玉米催芽机播和园艺、林业工厂育苗基地配套尤为适宜,被农业部农机推广总站列为使用较好的首选稻种催芽设备。机具特点1.温控仪精度高(100℃误差不大于0.5℃),量程宽(0℃～100℃),电压宽(165V～255V。)2.温度均匀,发芽快、齐、匀、壮,经15～20小时…     

堆肥物料容重、温度对频域反射传感器检测模型的影响

为探究堆肥物料容重和温度对频域反射法(FDR)含水率检测结果的综合影响规律,以猪粪和秸秆混合物料为研究对象,以基于FDR技术的FDS-100型水分传感器为检测仪器,研究了堆肥物料的含水率(35%～65%)、容重(602.41～758.58 kg/m~3)和温度(25～65℃)对传感器检测精度的影响,建立了传感器检测值与物料含水率、容重及温度之间的响应曲面模型,并对模型进行可行性分析。通过烘干法检测值与模型计算值建立了FDR水分传感器检测值与物料含水率之间的综合检测数学模型,并验证了模型准确性。结果表明:根据模型计算值与实际含水率的绝对误差范围为-1.1%～4.3%,平均绝对值误差为2.27%。本研究对开发具有容重和温度补偿功能的FDR堆肥物料含水率传感器的综合检测模型有指导作用。     

太阳能控温的干湿厌氧发酵对比试验研究

太阳能控温的厌氧发酵具有广阔的应用前景,目前国内外已有研究主要集中在太阳能控温湿发酵过程,尚没有太阳能控温的厌氧干发酵过程研究,为此搭建两套太阳能控温的干/湿厌氧发酵系统,在实际工况下进行批式厌氧发酵,研究太阳能控温下干/湿厌氧发酵启动情况,升温速率,温度波动性,发酵罐热负荷和典型天气下系统内各温度的变化情况。试验结果表明:在太阳辐射为1.2～21.6 MJ/m~2,平均环境温度变化范围为15.2℃～27.5℃的情况下,全玻璃真空管太阳能集热器能够确保干/湿发酵罐正常启动并维持干/湿发酵料液温度37℃±1℃恒温发酵,启动阶段湿发酵罐平均温度一直比干发酵高,温差最高可达2.5℃。增温过程中湿发酵罐平均散热损失比干发酵高0.14～0.27 MJ/d;而在控温阶段当系统经历连续阴雨天时,发酵温度波动不超过1.5℃,说明真空管太阳能集热器控温能力较强,可以满足发酵罐恒温发酵所需热量。     

水产饲料含水率预测模型研究

目前饲料烘干技术上最大的难点在于缺乏有效的干燥数学模型来准确预测饲料的含水率,为此,文章基于指数函数建立三种水产饲料的含水率预测数学模型,并进行试验验证.首先在循环风机频率为30 Hz,料层厚度为30 mm的条件下,对三种水产饲料进行单一温度(90℃、105℃、120℃、135℃)烘干试验,其次基于单一温度试验数据,采...     

氧化催化器出口温度控制研究

氧化催化器(DOC)出口温度控制是实现颗粒捕集器(DPF)主动再生控制热管理的关键。本文结合DOC系统的实际特征对系统进行分析,研究DOC传热及化学反应特性,建立了DOC一阶加延迟的载体出口温度响应模型,并利用载体试验数据进行了模型参数校核,同时建立了热响应特征模型时间常数及延迟时间常数与排气流量的关系。依据系统模型特征,研究了基于内模控制架构的PID控制策略,采用Pade二阶非对称近似方法对系统响应延迟部分进行处理,利用经典PID控制器与内模PID控制器等效方法建立了PID参数求解方程,分析了滤波器参数的设置方法。该控制策略通过台架试验,选取连续变化工况进行测试,DOC出口温度在排气流量及入口温度均大幅变化的情况下,可以确保出口温度控制在(575±20)℃范围内。     

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。