柴油机电控单体式喷油器（EUI）开启压力测试装置

通过对柴油机电控单体式喷油器（EUI）结构特点与工作原理的研究,设计一套便捷、快速、精确的柴油机电控单体式喷油器（EUI）开启压力测试装置.装置采用气压驱动喷油器挺杆,喷油器加压使其开启喷油,计量装置采用安装压力传感器,通过压力传感器获得加在喷油器挺杆上力的变化信号,利用高性能单片机编程来处理此信号,最后输出喷油器开启喷油的油压变化规律曲线,测出喷油器开启压力数值.     

基于RBF神经网络的汽车传感器故障诊断方法研究

简要说明RBF神经网络的构成及其算法,研究RBF神经网络发动机电子控制系统传感器的故障诊断方法,设计了一种发动机电子控制系统传感器诊断神经网络.借助流行的汽车OBDⅡ自诊断协议,组建发动机电子控制系统的诊断数据采集系统,以记录实验发动机电子控制系统工作时系统的输入/输出数据,根据实验数据进行诊断神经网络的训练和系统评价.     

微波传感器的信号识别及其应用

从微波传感器信号分析开始，论述了传感器输出A、B两相差动信号的识别电路及灵敏度的调整方法。给出了软件设计框图，并介绍了微波传感器的应用场合。     

精确林业传感技术和无线传感器网络研究进展

林业生产过程由多种生产作业分享时间和资源,需要实现以最少资源投入、最小环境危害、获得最大林业收益的精确林业目标。笔者围绕精确林业,综述了树木生长信息检测、树木胁迫信息检测、立木识别、林区立地检测、林区气候监测等林业作业目标识别与作业环境监测,以及林业机械作业参数监控的传感技术,并就林业多传感器融合、林业无线传感器网络及新型林业传感器进行了分析并提出研发建议,其中首次将精确林业传感器从工作环境角度分为固定式、移动式和随机式传感器3类,分析并提出相应林业传感器供电方式的建议。     

BJFG—1型光栅位移传感器位移检测原理

1　概　述BJFG- 1型光栅位移传感器是一种新型部件式金属反射光栅位移传感器。随着现代加工和计量技术的发展 ,对长度和位移测量不仅要求提高精度 ,而且要求能迅速而客观地将长度和位移测量结果以数字信号形式输出 ,以便进行数据处理和程序控制。光栅测量系统不但能以数字显示位移量 ,而且可以按预置指令程序来控制测量或加工过程 ,实现数字控制或伺服跟踪 ,因此 ,极大地提高了产品的质量和劳动生率。2　构成及原理光栅数显测量装置通常由光源、计量光栅、光电接收器、前置放大器、电子细分电路、计数器、显示装置等组成。其中 ,光源、光…     

多功能智能化电感测微仪的研究

研究开发了一种以ＭＣＳ５１系列８０３１单片机为核心,以差动电感式测量头为传感器、采用集成化测量电路和误差补偿技术的多功能智能化电感测微仪。它具有测量范围广、测量精度高、功能齐全、使用方便的特点,既能实现绝对零点与相对零点的自动转换、超差报警、设备上、下偏差,同时又能实现测量结果的自动显示,统计分析等功能。     

数字可编程式高速柔性联轴器的设计

设计了一种用于高速传动过程中扭矩传递的数字可编程式柔性联轴器.根据对不同连接引线孔的编组,实现不同扭矩的传递输出,从而达到对所传递输出扭矩的数字式可编程控制的目的.利用高速旋转实验台对这种数字可编程式柔性联轴器进行了试验测试,取得了很好的效果.     

汽车机油压力传感器

本项目采用厚膜力敏传感器技术和信号处理技术，开发汽车机油压力传感器。该传感器具有耐高温、耐腐蚀、无触点、能与数字化仪表相匹配、寿命长、性能价格比高等特点。该产品可以替代国内的滑线式油压传感器。     

锅炉光纤自控装置

锅炉光纤自控装置专利号：９５２０９４１３锅炉光纤自控装置采用光导纤维作为传感器，从锅炉双色水位中接收信号，从而解决了传统的电极式，浮筒式传感器受锅炉内部高压、高温结垢易出故障、可靠性差的问题。该装置从锅炉外部安装，所需辅助设施少，抗干扰能力强。适用于...     

网络传感器远程监控系统的设计

监控系统以ADuC841单片机作为嵌入式系统的中央处理单元,实现了单片机与RTL8019AS网卡的硬件电路连接,开发了应用于工业现场监测的网络传感器节点.该网络可以通过Internet响应远程客户端指令,并根据指令要求将现场已部署的传统传感器输出的模拟信号进行高速采样存储,再以Internet为物理通道,将数据打包回送到相应的远程客户端,从而完成远程客户端与监测现场的数据通信.     

基于分布图与分批估计的自校准层融合算法研究

为增强数据处理对不确定因素的适应性和鲁棒性,在研究检测系统多传感器数据融合结构的基础上,提出基于分布图与分批估计的自校准层融合方法。采用分布图和分批估计的融合算法不需要传感器先验信息。理论分析和实验研究表明：分布图法对检测数据的一致性估计与最佳融合集相同;自校准层融合输出数据精度高于算术平均值,也优于分布图法消除不确定因素后数据的算术平均值。该算法尽可能多的保持现场数据,在某个传感器失效情况下,非失效传感器仍可独立提供可靠数据,适用于智能检测融合系统中自校准层的实时在线数据处理。     

Estimating sap flux densities in date palm trees using the heat dissipation method and weighing lysimeters

In a world of diminishing water reservoirs and a rising demand for food, the practice and development of water stress indicators and sensors are in rapid progress. The heat dissipation method, originally established by Granier, is herein applied and modified to enable sap flow measurements in date palm trees in the southern Arava desert of Israel. A long and tough sensor was constructed to withstand insertion into the date palm's hard exterior stem. This stem is wide and fibrous, surrounded by an even tougher external non-conducting layer of dead leaf bases. Furthermore, being a monocot species, water flow does not necessarily occur through the outer part of the palm's stem, as in most trees. Therefore, it is highly important to investigate the variations of the sap flux densities and determine the preferable location for sap flow sensing within the stem. Once installed into fully grown date palm trees stationed on weighing lysimeters, sap flow as measured by the modified sensors was compared with the actual transpiration. Sap flow was found to be well correlated with transpiration, especially when using a recent calibration equation rather than the original Granier equation. Furthermore, inducing the axial variability of the sap flux densities was found to be highly important for accurate assessments of transpiration by sap flow measurements. The sensors indicated no transpiration at night, a high increase of transpiration from 06:00 to 09:00, maximum transpiration at 12:00, followed by a moderate reduction until 08:00; when transpiration ceased. These results were reinforced by the lysimeters' output. Reduced sap flux densities were detected at the stem's mantle when compared with its center. These results were reinforced by mechanistic measurements of the stem's specific hydraulic conductivity. Variance on the vertical axis was also observed, indicating an accelerated flow towards the upper parts of the tree and raising a hypothesis concerning dehydrating mechanisms of the date palm tree. Finally, the sensors indicated reduction in flow almost immediately after irrigation of field-grown trees was withheld, at a time when no climatic or phenological conditions could have led to reduction in transpiration.     

Predicting moisture content and density distribution of Scots pine by microwave scanning of sawn timber

This study was carried out to investigate the possibility of calibrating a prediction model for the moisture content and density distribution of Scots pine (Pinus sylvestris) using microwave sensors. The material was initially of green moisture content and was thereafter dried in several steps to zero moisture content. At each step, all the pieces were weighed, scanned with a microwave sensor (Satimo 9,4GHz), and computed tomography (CT)-scanned with a medical CT scanner (Siemens Somatom AR.T.). The output variables from the microwave sensor were used as predictors, and CT images that correlated with known moisture content were used as response variables. Multivariate models to predict average moisture content and density were calibrated using the partial least squares (PLS) regression. The models for average moisture content and density were applied at the pixel level, and the distribution was visualized. The results show that it is possible to predict both moisture content distribution and density distribution with high accuracy using microwave sensors.     

Medium-term sap flux monitoring in a Scots pine stand: analysis of the operability of the heat dissipation method for hydrological purposes

The operability of Granier-type heat dissipation sap flow meters for the medium-term monitoring of Scots pine transpiration was tested. Three sensors that had been working for 3 years were duplicated by inserting new sensors in the same trees. The new sensors operated simultaneously with the old sensors for 18 months. Analysis of the temporal patterns of thermal dissipation of the sensors showed a slight, but significant decrease in all sensors, indicating the conservation of sapwood thermal properties. Although there was a high correlation between sap flux densities registered by the old and new sensors, significant differences in sap flux densities between the duplicated sensors were detected. Such differences could not be attributed to tissue injury around the sensors or to loss of sensitivity of the old sensors, because two of the old sensors registered higher flux rates than the new sensors. No instrumental error to explain the sap flux differences was found. Because the new sensors were installed at some angular distance from the old sap flow meters to avoid thermal interferences, it was inferred that the observed sap flux differences between duplicate sensors were the result of an azimuthal sap flow pattern.     

A micro-power precision amplifier for converting the output of light sensors to a voltage readable by miniature data loggers

To record photosynthetically active radiation (PAR) simultaneously at a number of points throughout a forest canopy, we developed a simple, inexpensive (< $10 US) current-to-voltage converter that processes the current generated by a photodiode radiation sensor to a voltage range that is recordable with a miniature data logger. The converter, which weighs less than 75 g and has a volume of only 100 cm(3), is built around an ultra-low power OP-90 precision operational amplifier, which consumes less than 0.5 mA at 9 V when converting the output of a Li-Cor LI-190SA quantum sensor exposed to photosynthetically active radiation (PAR) of 2500 &mgr;mol m(-2) s(-1) or only 5 &mgr;A in low light. A small 9-V battery thus powers the amplifier for more than 1000 h of continuous operation. Correlations between photometer readings and voltage output from the current-to-voltage converter were high and linear at both high and low PAR. Sixteen Li-Cor LI-190SA quantum sensors each equipped with current-to-voltage converters and connected to a miniature data logger were deployed in the upper branches of a Panamanian tropical rainforest canopy. Each unit performed reliably during a one- or two-week evaluation.     

Spatial sap flow and xylem anatomical characteristics in olive trees under different irrigation regimes

The compensation heat pulse (CHP) method is widely used to estimate sap flow and transpiration in conducting organs of woody plants. Previous studies have reported a natural azimuthal variability in sap flow, which could have practical implications in locating the CHP probes and integrating their output. Sap flow of several olive trees (Olea europaea L. cv. 'Arbequina') previously grown under different irrigation treatments were monitored by the CHP method, and their xylem anatomical characteristics were analyzed from wood samples taken at the same location in which the probes were installed. A significant azimuthal variability in the sap flow was found in a well-irrigated olive tree monitored by eight CHP probes. The azimuthal variability was well related to crown architecture, but poorly to azimuthal differences in the xylem anatomical characteristics. Well-irrigated and deficit-irrigated olive trees showed similar xylem anatomical characteristics, but they differed in xylem growth and in the ratio of nocturnal-to-diurnal sap flow (N/D index). The results of this work indicate that transpiration cannot be accurately estimated by the CHP method in olive trees if a small number of sensors are employed and that the N/D index could be used as a sensitive water status indicator.     

不同数量传感器下云杉模拟缺陷材应力波成像规律探讨

以云杉原木圆盘为对象,研究不同面积、不同轮廓形状的空洞缺陷及用不同数量传感器情况时应力波成像技术检测缺陷图像与实际缺陷的关系.结果表明:应力波成像系统可以直观显示木材内部缺陷,其检测精度与空洞等实际缺陷面积和被测木材的截面积比率、使用传感器数量及空洞等缺陷轮廓形状有关;当空洞实际面积与被测木材截而积比从1.6％上升到25.0％时,应力波成像系统显示缺陷图像面积与实际缺陷面积相对误差从22.6％下降到9.7％;成像用传感器数量在6～24个之间时,应力波成像系统均能显示空洞等缺陷的存在,但成像用传感器的数量会影响检测精度;缺陷轮廓形状对应力波成像有一定影响,缺陷面积一定时,狭长形缺陷容易被检出,近圆形缺陷检测相对误差小.     

Research on Stress Wave Tomography of Spruce Logs with Artificial Defects under Different Number Sensors

In order to raise the precision of stress wave imaging technology(SWIT),under the conditions of different area and outline of simulated cavity defects in timber discs of spruce,different number of used sensors,the relationship between imaging graph defects and real defects is studied. The result shows:SWIT can display graph of defects,the precision of imaging graph relates to rate of real defect area and area of the tested wood cross section,the number of used sensors and outline shape of the defects.When the rate rises from 1.6% to 25.0%,the relative error of graph defect area and real defect area drops from 22.6%to 9.7%.When the number of used sensors is from 6 to 24,the graph of SWIT can show the existence of real defect. But the number of sensors used influences the precision of SWIT.Outline shape of defects has certain effect on detection of defects.Under the condition of the same defect area,the defects of long and narrow shape are easy to be shown by graph.The relation error of defect area of suborbicular shape is smaller than that of long and narrow shape.     

用瞬态激励法标定压力传感器参考灵敏度

介绍一种用瞬态激励法测定压力传感器参考灵敏度的方法.通过对已知和未知力传感器频谱、频响函数幅值及相位图等的分析,测定未知力传感器的参考灵敏度.此法测试简单,对木材工业的结构动力学测试工作具有一定的实用价值.