基于单片机的肥箱料位传感器设计与试验

针对颗粒化肥在田间施肥过程中的肥箱料位实时在线测量问题,研制了一种新型的基于电容法的肥箱料位传感器,并通过对其硬件电路和软件程序的设计分析,开发出了以STC89C52单片机为核心的传感器监测系统。该传感器把肥料箱的料位转换为电容量的变化,将电容变化转变为脉冲信号频率变化,并输入信号给单片机,经过单片机程序计数,LED数码管显示肥箱料位高度百分比测量值,并通过串口传输到上位机。试验结果表明:该肥箱料位传感器工作稳定可靠、成本低,能够对肥箱料位情况进行实时在线监测,使施肥机信息化水平得以提高。     

对射式红外线计数器的设计

利用加密、解码红外线发射、接收模块作计数传感器,当有物体通过时光被遮挡住,接收模块输出一个高电平脉冲,对此脉冲进行计数,就可实现对产品的统计。基于这种光电检测原理,配合四合一组合集成电路,设计了对射式红外线计数器。实践证明,该装置抗干扰能力强,工作稳定,计数准确。     

100进制计数器的设计

文章以100进制计数器为例,介绍计数器的设计过程:利用数字电子技术知识完成电子制作,选择NE555外加少量的电阻和电容元件构成多谐振荡器,多谐振荡器产生的信号为计数芯片74LS90提供脉冲信号,两片74LS90构成100进制计数器,利用74LS48D驱动七段数码管显示00-99。     

基于单片机及红外传感的电子脉搏计设计

文章设计的脉搏计系统以单片机AT89C51和红外光电传感器为核心,充分使用单片机的内部软件资源,减少部分硬件电路设计。红外光电传感器检测脉搏信号,并转换成电脉冲信号,经电路的放大、滤波、整形处理,滤除杂散信号,获得规则的脉冲波形,最后通过单片机控制实现基准定时、脉搏计数、倍频及译码,在数码管中实时显示脉搏数。文章详细介绍了系统总体方案及部分软硬件设计方案。     

单片机在温度仪中的应用

本文阐述了单片机在简单的数字温度测量仪设计过程中的应用。以温度传感器AD590经LM324放大电路,将温度信号转换为电压信号,通过AD变换器ADC0809,将温度信号传送给单片机AT89C52。单片机通过查询方式将ADC0809转换的数字信号进行采集处理,送LED进行显示,最后温度可以直接由LED读取。     

AT89S52在电机转速测量中的应用

用AT89S52单片机作微处理器，设计出一个电动机转速测量系统，并研究其测量精度、测量范围及响应速度。程序设计部分分为初始化模块、脉冲计数模块、计时模块、参数调整模块和显示模块。最后通过试验测试．得到了相应的技术参数，并对转速测量系统的误差进行了分析。     

鸡蛋电特性检测系统的设计

为了给无损检测鸡蛋的新鲜度提供一种方法,基于生物体电特性的检测原理,设计了一个鸡蛋电特性的检测系统.该系统主要由信号发生模块、检测模块、模数转换模块、DSP计算模块、输入和显示模块等组成.信号发生模块采用直接数字频率合成(DDS)芯片AD9851,检测模块采用幅相测量芯片AD8302,模数转换采用AD7705,DSP选用TMS320VC5402并使用CORDIC迭代算法计算电特性,人机交换模块由单片机89S52控制键盘和液晶显示器完成,所有模块由DSP实现初始化和控制.     

电子式电能表的原理及故障检查

电子式电能表的工作原理是将用户消耗的电能，通过对分压器和分流器上的信号取样，送到乘法器电路，乘积信号再送到V／F变换器，决定输出方波脉冲的频率，此功率脉冲一方面通过发光二极管显示工作状态，另一方面经过光耦耦合输出，供计量和远程抄表用。由于输出的是占空比为５０％的脉冲方波，因此发光二极管亮、暗频率的快慢，表示用电量大小，常亮或常暗都表示该用户未用电。功率脉冲经１６分频后的信号交替输出，推动步进电机带动字轮计数，电子式电能表随着用户用电功率的增加，指示灯闪亮越来越快，每闪亮８次，计数器前进一步。如用…     

可燃性气体泄漏报警器设计

以STC12C5A60S2单片机为核心,用气敏传感器（MQ-7）设计一可燃气体泄漏报警器。主要由可燃气体传感器、信号处理电路、单片机系统、显示及报警等组成。信号由气敏传感器检测,经过放大电路处理,由单片机内部AD转换器读入单片机,单片机对检测到的信号进行判断并将实测浓度值显示。若气体浓度超过预定数值时,将发出声光报警,同时切断气源,启动排气扇。实现了可燃气体的检测、报警、显示和相应处理功能,具有广泛的应用价值。     

基于单片机的烟草育苗大棚温湿度监测系统设计

烟草是一种非常重要的经济作物,而育苗是烟草种植过程中特别重要的一个环节.课题组把单片机技术、传感器技术、通信技术应用到烟草育苗中,设计了以单片机为核心的监测系统.该系统的硬件部分主要包括主控模块、显示模块、温湿度传感模块、报警模块、通信模块等部分.该系统能够将实时检测的温湿度在液晶屏上显示,如果监测到温湿度超过所设定的...     

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。     

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。     

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.