Detection of cell-affecting agents with a silicon biosensor

Cellular metabolism is affected by many factors in a cell's environment. Given a sufficiently sensitive method for measuring cellular metabolic rates, it should be possible to detect a wide variety of chemical and physical stimuli. A biosensor has been constructed in which living cells are confined to a flow chamber in which a potentiometric sensor continually measures the rate of production of acidic metabolites. Exploratory studies demonstrate several applications of the device in basic science and technology.     

容栅式多相界面测控系统的研制

研制开发了一种具有工业应用价值的油、气、水分离器专用的容栅式多相界面测控系统。该系统能够指示出水／乳、乳／油、油／气界面的具体位置，适应不同油田测量的需要，并具备智能化的特点，改变了以往的单一界面的物位测量。采用电量检测技术的平行板式电容传感阵列，对界面进行了检测，有较高的精确度。整个系统的结构紧凑，易于制作，工作性能稳定可靠。该项技术的开发，具有一定的技术价值和广泛的应用前景。     

一种基于ARM的温室数据采集系统的设计

介绍了温室采集系统硬件采用的高性能32位ARM系列微控制器LPC2132,先进的温湿度、光照、CO2传感器和LCD显示模块,软件设计采用了实时多任务操作系统,保证了系统的实时性和可靠性。     

A review of advanced techniques for detecting plant diseases

Diseases in plants cause major production and economic losses in agricultural industry worldwide. Monitoring of health and detection of diseases in plants and trees is critical for sustainable agriculture. To the best of our knowledge, there is no sensor commercially available for real-time assessment of health conditions in trees. Currently, scouting is most widely used mechanism for monitoring stress in trees, which is an expensive, labor-intensive, and time-consuming process. Molecular techniques such as polymerase chain reaction are used for the identification of plant diseases that require detailed sampling and processing procedure. Early information on crop health and disease detection can facilitate the control of diseases through proper management strategies such as vector control through pesticide applications, fungicide applications, and disease-specific chemical applications; and can improve productivity.The present review recognizes the need for developing a rapid, cost-effective, and reliable health-monitoring sensor that would facilitate advancements in agriculture. It describes the currently used technologies that can be used for developing a ground-based sensor system to assist in monitoring health and diseases in plants under field conditions. These technologies include spectroscopic and imaging-based, and volatile profiling-based plant disease detection methods. The paper compares the benefits and limitations of these potential methods.     

车载行进式农田土壤压实度实时测量系统

基于应变片测力原理研制了一种新型嵌入式土壤压实度传感器和车载行进式农田土壤压实度实时测量系统。该系统将微型压力传感器嵌入到锥体前部,直接测量行进过程中锥头受到的土壤阻力,简化了测量结构,提高了系统的复合度。以超低功耗MSP430单片机作为内核的数据采集器实现了多路模拟信号的测量,2个串口分别用于与上位机的通讯和GPS信号的接收,采用PDA作为数据处理、存储以及显示终端。传感器实验室标定结果表明,嵌入式土壤压实度传感器输出电压与标准载荷具有良好的线性关系。田间试验结果表明,车载行进式农田土壤压实度实时测量系统工作稳定,土壤压实度测量结果与GPS信息融合效果良好,系统能够快速获取农田土壤压实度及其空间变异信息。     

便携式土壤电导率测试系统的开发

介绍了一种自行设计的，基于电流-电压四端法的便携式土壤电导率(EC)在线测试仪的开发情况。该测试仪包括土壤电导率传感器、控制与数据采集器和计算机应用软件等。传感器有4个电极，2个用于向土壤中输入恒流，另外2个用于检测与土壤电导率密切相关的电压降；控制与数据采集器把传感器产生的电压信号转换为数字信号，计算并显示电导率；计算机应用软件把接收到的数据存入Microsoft Access数据库。在实验室土槽内对该测试仪传感器的性能进行了测试，并与电导率仪测量结果进行了比较分析。结果表明，传感器输出电压与电导率仪测量值变化趋势一致，采用多种非线性数学模型对各组数据进行了曲线拟合，结果均在幂函数模型上获得最佳回归，测定系数(R^2)大于0．99。     

Variable-rate fungicide spraying in real time by combining a plant cover sensor and a decision support system

In recent years, real-time technology has been introduced into the practice of spraying variable fungicide rates in cereal fields. Plant parameters for characterising heterogeneous plant growth such as biomass or plant surface area can be indirectly detected by the sensor CROP-Meter. The sensor signal is correlated with the Leaf Area Index, which can be used to adapt the application rate. However, this relatively simple method of controlling variable-rate fungicide application does not take into account the differences in disease distribution. In practice, decision support systems such as proPlant expert.classic can provide information about disease infection probabilities, application time, fungicide products and application rates for uniform spraying. A prototype of the system proPlant expert.precise was developed to estimate infection risks from fungal diseases using weather and field-specific data for up to three management areas with different yield expectations. The system also considers economic factors such as expected yield and costs of the fungicide products in generating a spraying map with different fungicide dosages. The information from the CROP-Meter (sensor) and from the decision support system proPlant expert.precise (map) was combined to provide a real-time spraying system with map overlay. The system was tested in 2007 in three winter wheat fields. Compared with conventional uniform spraying the CROP-Meter with map overlay treatment resulted in up to 32.6% fungicide savings (CROP-Meter versus uniform: up to 20.3%). There was no yield reduction on average when the sensor-controlled spraying technologies were used.     

农田信息采集系统中传感器网络簇内广播认证方案研究

传感器网络在农业生产信息采集领域具有一定应用前景,有限的节点资源限制了传感器网络的实际应用。借鉴分簇传感器网络在提升系统吞吐量、降低系统延迟以及节省能量方面显示出越来越大的优势,在农业环境监测传感器网络中引入分簇思想。已有的动态簇形成方案的典型代表是LEACH,该方案存在安全威胁,而且协议没有提供广播认证功能。由于簇首选择及簇形成的动态性使得大多数已有安全方案不适用于分簇传感器网络。该研究在基于分簇的传感器网络协议中加强安全性考虑,引入簇内广播认证机制,提出针对LEACH的安全解决方案,基于该方案的农田信息采集系统传感器网络性能得到有效提高。     

The effect of sensor errors on production and energy consumption in greenhouse horticulture

The accuracy of sensors used in Dutch greenhouses for climate control has been assessed and the influence of sensor errors on the energy consumption and crop production has been determined using model simulations. It is shown that currently used sensors are prone to errors exceeding current standards set for practice. The extra energy consumption, due to sensor inaccuracy, is mainly caused by the sensors for global radiation and relative humidity. Sensor errors may result in a higher crop production but at the expense of a higher energy consumption resulting in a loss in economic return of the crop production process. Results indicate that sensor maintenance is economically feasible because the resulting energy savings exceed the costs of the maintenance operation.     

基于ARM的温室环境监控系统的湿度采集设计

提出了一种以ARM处理器LPC2212为核心的温室环境监控系统的湿度采集设计方案,系统采用SHT71为湿度传感器,LPC2212为控制器,实现了对温室环境的湿度参数采集。在此基础上,详细阐述了湿度采集电路的硬件设计和软件实现。     

A ground-based hyperspectral imaging system for characterizing vegetation spectral features

A cropping system is usually characterized by continuous spatio-temporal vegetation variability. Vegetation variability can be detected by changes in several vegetation parameters defined according to purpose. Estimation of these vegetation parameters has been made possible by calculating various vegetation indices (VIs), usually by ratioing, differencing, ratioing differences and sums, or by forming linear combinations of spectral band data. Spectrometers or sensors have been used to acquire visible and infrared spectral properties of vegetation. This paper presents a ground-based hyperspectral imaging system for characterizing vegetation spectral features. The hyperspectral sensor used was a ground-based line sensor, ImSpector (V10-12-102), with a nominal spectral resolution of 1.5–2 nm and a wavelength range of 360–1010 nm. A graphical user interface (GUI) was developed in a MATLAB environment to aid in processing and analysis of acquired multidimensional spectral image data. Issues that arise when applying the imaging system to a particular field include acquiring hyperspectral images, selecting appropriate vegetation features or VIs, and quantifying the selected vegetation features or indices with the GUI developed. Vegetation features extracted by the proposed imaging system contribute not only to monitoring vegetation variability in crop systems, but also provide a potential source of relevant variables that can be used to estimate various vegetation parameters. A study that was set up to investigate the alternate bearing phenomenon of citrus trees illustrates the basic elements of the proposed approach.     

Chemical detection with a single-walled carbon nanotube capacitor

We show that the capacitance of single-walled carbon nanotubes (SWNTs) is highly sensitive to a broad class of chemical vapors and that this transduction mechanism can form the basis for a fast, low-power sorption-based chemical sensor. In the presence of a dilute chemical vapor, molecular adsorbates are polarized by the fringing electric fields radiating from the surface of a SWNT electrode, which causes an increase in its capacitance. We use this effect to construct a high-performance chemical sensor by thinly coating the SWNTs with chemoselective materials that provide a large, class-specific gain to the capacitance response. Such SWNT chemicapacitors are fast, highly sensitive, and completely reversible.     

压电晶体化学传感器研究进展

本文综述了压电晶体化学传感器在气相、液相物质和生物学上的应用，介绍了压电晶体化学传感器的新型装置（如传感器阵列）、新型敏感材料.     

烟草漂浮育苗繁育烟蚜茧蜂的影响因素探讨

烟蚜茧蜂是烟蚜的优势寄生性天敌,对烟蚜具有较好的控制作用。通过烟草漂浮育苗繁育烟蚜茧蜂防治烟蚜技术已日趋成熟并在云南烟草上得到大规模应用。该项生物防治措施的推广将是实现农业生产大幅度降低化学农药使用量的重要途径。文章对影响该技术各环节的因素进行了分析探讨,提出优化烟草漂浮育苗繁育烟蚜茧蜂效果的措施和对策,建议系统研究制约烟草漂浮育苗繁育烟蚜茧蜂的技术瓶颈,探索产业化途径,为烟蚜茧蜂更广泛的应用提供依据和技术支撑。     

农田信息采集系统中传感器网络簇首认证方案研究

在农田信息采集系统的传感器网络中引入分簇结构,可提升系统吞吐量、降低系统延迟以及节省能量。但已有的分簇方案并未在簇形成及稳定阶段对簇首身份进行认证。文章针对簇首认证问题提出了BA-LEACH协议,并通过仿真试验表明协议以较低的能耗增强了系统中分簇传感器网络的安全性。     

基于Zigbee的播种质量监控系统的设计

为了满足智能化农业的需求,应用无线传感网络技术和PLC控制器技术,设计了一个基于Zigbee的播种质量无线监控系统。该系统采用光电传感器实现对排种状态的检测,采集的信息通过无线传输模块发送到PLC;利用霍尔传感器检测拖拉机行进速度,步进电机驱动排种轴,以实现播种状况的实时检测、控制及排种速度与拖拉机速度的同步。试验表明：该系统具有高可靠性、高精度的特点,在高速通信的同时有效地实现了播种信息的实时监控。     

基于灰色关联分析模型的烟叶化学成分评价研究进展

利用烟叶化学成分评价烟叶质量一直是烟草研究的热点,大量统计学方法已广泛应用于评判烟叶等级。灰色关联分析作为一种新颖的因素分析方法,通过对序列几何关系的度量来比较系统中多因素关系的紧密程度,其紧密程度可由序列曲线间几何形状的接近程度来度量,灰色关联分析在挖掘烟叶化学组分信息中具有广阔的应用前景。以烟叶化学成分作为主线,综述了烟叶品质评价的现况,并对灰色关联分析模型在烟叶化学成分评价上的应用进行了系统分析,同时比较了几种经典灰色关联度模型的算法和性质,以期为卷烟工业构建烟叶质量评价方法体系提供参考。     

水产品活体运输智能监控系统的设计

近些年来消费者对水产品的新鲜度和安全度要求越来越高,活体运输成为有效的保鲜方式之一,但国内水产品的活体运输技术存在着信息化、智能化程度低,监控因素单一等亟待解决的问题。针对上述问题设计了一种水产品活体运输智能监控系统,通过硬件和软件的设计,对运输车箱内水环境的温度、p H、溶解氧等水质环境参数和视频数据进行实时监控。该系统构建了底层传感器检测与控制、监控中心数据处理、远程终端管理的三层物联网结构,通过无线传输技术,实现了水产品活体运输的远程智能监控。该系统通过Lab VIEW软件设计了上位机监控界面,不仅可以实时显示运输过程中水产品的各水质环境参数及车内安全视频监控数据,还建立了水产品数据库,可进行历史数据的查询。经过小型罗非鱼活体运输车辆的测试,该系统运行稳定可靠,操作简便,具有良好的实用价值。     

一种具有平顶陡边响应的长波长光探测器

在PIN型光探测器的基础上制备了一种适用于波分复用系统的具有平顶陡边响应的长波长光探测器。利用低压金属有机化学气相沉积(LP-MOCVD)设备在GaAs衬底上二次外延生长了具有台阶结构的GaAs/AlGaAs滤波腔和InP基PIN光探测器。高质量的GaAs/InP异质外延采用了低温缓冲层生长工艺;具有台阶结构的Fabry-Pérot(F-P)滤波腔采用了纳米量级台阶的制备方法。通过理论计算优化了实现平顶陡边光谱响应特性的器件结构;并通过实验成功制备出了具有平顶陡边响应性能的光探测器,器件的工作波长位于1 549nm,峰值量子效率大于25%,0.5dB光谱响应线宽为3.9nm,3dB光谱响应线宽为4.2nm,响应速率达到17GHz。     

Implementation of a low-cost crop detection prototype for selective spraying in greenhouses

During phytosanitary treatments aimed at minimizing product losses, selective spraying systems can be employed. These systems consist of a group of detection–action devices which manage the spraying. In this work, the technical feasibility of a low-cost ultrasound detection system prototype has been assessed for pesticide spray application on greenhouse crops. The prototype is based on a commercially-available car parking assistance system, which has been modified to amplify the signal and activate an electro-valve for spray control. This system was fitted into a self-propelled machine with two vertical spray booms. A laboratory test was carried out to evaluate the system limitations (detection range, response time, optimal sensor location); and once the feasibility of the system was known, a field test was conducted. Inside the greenhouse, the same parameters were determined for canopy presence. The system’s capacity to start and stop spraying at the beginnings and ends of the crop lines was also analysed. In addition, the minimum crop line surface with no plant mass that triggers system activation was determined. The results show that the detection range was 0–0.4 m with an average response time of 1.67 s. Based on these parameters, the optimal sensor location was determined for the different forward velocities. In conclusion, the results show that this system is suitable for plant detection at a forward speed of 0.9 m s^?1, allowing growers to stop spraying automatically at the ends of the crop lines and where plant mass absence is greater than 1.0 lineal meter.