搜索结果: 1-15 共查到“TDR”相关记录33条 . 查询时间(0.156 秒)
Rapid Percolation of Water through Soil Macropores Affects Reading and Calibration of Large Encapsulated TDR Sensors
gap preferential flow rain sensor installation
2015/7/28
The electromagnetic soil water content sensors are invaluable tools because of their selective sensitivity to water,
versatility, ease of automation and large resolution. A common drawback of most t...
基于相位检测原理的TDR土壤电导率测量研究（Research of Soil Conductivity Measuring Technique with TDR Based on Phase Detecting Principle）
土壤 电导率 盐分 时域反射
2010/12/29
介绍了基于相位检测的时域反射（P-TDR）技术的工作原理。对8种不同盐分含量的砂壤土土样在5个含水量水平下进行实验，结果显示，信号的反射系数随电导率增加单调减小。分别采用线性和二次多项式对测量结果进行建模实验，并选择二次多项式为P-TDR电导率测量模型，模型的决定系数达0.812以上。土壤含水量对电导率测量有较大影响，在分析了土壤含水量与多项式系数关系的基础上，最终建立了以土壤含水量和反射系数为变...
高盐分环境下TDR测试高含水率方法研究
TDR 高含水率 高含盐量 介电常数
2011/6/9
有效采用TDR技术测试土体含水率的关键在于建立介电常数与体积含水率之间的定量关系，目前常用的介电常数与体积含水率之间的Topp经验关系式是建立在低盐分环境下较低含水率条件下的。通过一系列室内试验，探讨了高含盐量环境下高含水率海相淤泥的介电常数与体积含水率的关系。研究结果表明，Topp经验关系式不适用于含盐量为1.5%～4.5%和质量含水率为120%～320%的海相疏浚淤泥。为了快速连续测试海相疏浚...
应用倒谱域滤波的TDR波形分析
复倒谱 TDR 波形分析
2009/12/28
倒谱域滤波能够有效的滤除多次反射回波。该文将倒谱域滤波方法引入TDR(Time Domain Reflectometry)波形分析，通过将TDR波形在倒谱域内做滤波，滤除多次反射回波对时域波形的影响，进而快速准确测定脉冲在探头上传播时间，反演土壤表观介电常数。利用倒谱域滤波法测试结果与双切线法结果相比，具有更高的测试精度。
Spatial and Temporal Distribution of Soil Water Content in Fields under Different Vegetation Conditions Based on TDR Measurements
electromagnetic wave Andisol multiple probes with different lengths
2009/9/10
TDR (Time-domain reflectometry) is an advanced method for monitoring the water content in fields.TDR measurements can provide accurate information about vegetation effects on both spatial and temporal...
Preferential transport of water and 131Iodide in a clay loam assessed with TDR-techniques and boundary-layer flow theory
clay loam soil moisture variations boundary-layer flow
2009/6/8
Rapid soil moisture variations were measured with TDR equipment at five depths ranging from 0.1 to 0.9 m during five consecutive infiltration experiments under ponding. Each time, 27 mm of water were ...
Extension of the measurement range of electrical conductivity by time-domain reflectometry (TDR)
electrical conductivity time-domain reflectometry
2009/6/8
The electrical conductivity (EC) of a medium invaded by TDR sensors can be estimated from the impedance of a TDR reflectogram. Four categories of sensor were tested in salt solutions and the impedance...
A fast TDR-inversion technique for the reconstruction of spatial soil moisture content
soil moisture TDR-inversion technique
2009/5/18
Spatial moisture distribution in natural soil or other material is a valuably information for many applications. Standard measurement techniques give only mean or punctual results. Therefore a new inv...
Efficient reconstruction of dispersive dielectric profiles using time domain reflectometry (TDR)
time domain reflectometry dispersive dielectric profiles
2009/5/13
We present a numerical model for time domain reflectometry (TDR) signal propagation in dispersive dielectric materials. The numerical probe model is terminated with a parallel circuit, consisting of a...
一种基于TDR测量的高速连接器的MMTL模型
时域测量 时域反射计 连接器
2009/4/3
该文提出了一种全新的高速连接器时域模型MMTL(Multi-segment Multiple Transmission Line model)。该模型克服了MLC模型不稳定和仿真效率低的缺点，具有直观、精度可控、便于优化等优点。实验结果表明，该文所建模型精度高，与实际测量的最大误差小。
Practical considerations on the use of down-sized time-domain reflectometry (TDR) probes
TDR probepulse travel time dielectric constant electrical conductivity
2009/3/17
Nine time-domain reflectometry (TDR) probes, 2 to 10 cm long, were evaluated by comparing their measurement accuracy of TDR-pulse travel time in a sand and sandy loam soil, and electrical conductivity...
在甜椒（Capsicum frutescens L.）花药培养中3H-TdR掺入的放射自显影。
Application of TDR measurement technology for construction materialsin semi-scale experiments**
moisture content two-needle TDR sensors semi-scale experiments construction materials
2008/11/26
Application of TDR (Time-Domain Reflecto- metry) measurement technology for the investigation of hygric performance for construction materials in the conditions of a semi- scale experiment is present...
Accuracy of soil moisture measurement by tdr technique
time domain reflectometry soil moisture measurement error
2008/11/26
The error in the measurement of volumetric water content by the TDR technique results from the correlation imperfections between the directly measured values of soil refractive index, n, and the real ...
Application of TDR measurement technology for construction materialsin semi-scale experiments: A practical example
moisture content TDR thermal insulation
2008/11/26
A practical example of the application of TDR (Time-Domain Reflectometry) measurement technology for investigation of hygric performance of systems of construction materials in a semi-scale experiment...