用于估算冻土中液态水分量的TDR数据校正(英文)

TDR作为1种野外测量土壤水分量简便而准确的方法而被人们熟知和使用。本研究使用TDR在河套灌区对冻土在冻结融解时进行了土壤水分测定。为了用TDR数据计算冻土的液态水分量,文中分析了众多计算模型和经验模型,最终找到了最适合本地区土壤特性的B irchak模型。     

深松和压实对旱地棕壤硬度和水分入渗性能的影响

通过比较分析深松与压实及对照处理棕壤农田土壤的硬度剖面分布和水分入渗曲线变化,研究不同耕作措施对土壤机械物理性质和通透性能的影响。结果表明:(1)深松和压实处理后,0~25 cm土层硬度大小顺序为压实对照深松,25~40 cm土层的硬度为深松压实对照;而这一处理效果随处理后时间的延长而逐渐减弱,但90天后0~25 cm土层处理间差异依然存在,而25~40 cm土层这一差异不明显;(2)菲利浦公式能较好地表达压实、深松和对照处理土壤水分入渗速率随时间的变化过程,且不同处理及各处理重复间的土壤入渗曲线变异性较大;(3)对各处理土壤入渗菲利浦公式做标定处理求得的代表性入渗曲线,其初始入渗速率大小顺序为深松对照压实,而稳定入渗速率则为对照压实深松处理;说明深松和压实对土壤入渗能力影响明显不同,深松不仅能提高前期土壤水入渗能力、还能抑制入渗后期的深层渗漏。     

基于RBF神经网络的土壤含水量传感器标定方法

土壤含水量时空变异对作物生长、农田气候变化等领域的研究具有重大意义。为了克服TDR-3土壤水分传感器输出电压的非线性缺点,提高土壤含水量数据采集以及计算效率,将TDR-3土壤水分传感器与无线传感器网络结合,提出了土壤水分含量的RBF神经网络标定方法。结果表明,该法能取得较好的标定效果,且操作简单、实用、可行,为土壤含水量的实时监测提供了一种有效的方法。     

大型结构部件载荷标定试验方法研究

以收音机机翼等大型结构为例,探讨了大型结构部件载荷标定试验的力学模型。通过结构部件直接进行应变桥路传感器设计和标定、加载试验的现场实施以及对试验数据的分析处理、优化与检验、置信区间探讨,建立了以飞机机翼、尾翼等大型结构部位为例的载荷输入与应变输出关系方程,以此来获得载荷测量截面在实际工作过程中的载荷－时间历程,为大型结构部件的寿命估算、可靠性设计等提供重要依据。     

Evaluation and comparison of two immunoturbidimetric assays for the heterologous determination of porcine serum C-reactive protein

The objective was first to evaluate the performance (intra- and inter-assay imprecision, inaccuracy, detection limit and overlap performance) of two different commercially available human C-reactive protein (CRP) immunoturbidimetric assays (TIA) applied to porcine serum CRP; and secondly to investigate inter-laboratory discrepancies and the influence of calibration materials when comparing results. The intra-laboratory performance seemed acceptable for clinical purposes for both assays with excellent overlap performance, acceptable detection limits, no significant inaccuracies and low imprecision. Although a significant discrepancy in the measured CRP levels was observed when comparing results, the methods agreed significantly on diagnostic classification, suggesting a low clinical significance. Both assays performed reliably for the heterologous determination of porcine serum CRP for clinical purposes. The results emphasise the need to establish species-specific standards to decrease inter-laboratory discrepancies.     

Double extended octagonal ring (DEOR) drawbar dynamometer

A drawbar dynamometer is required to measure drawbar forces in field research on energy inputs for agricultural field equipment. In this study, a 2D double extended octagonal ring (DEOR) drawbar dynamometer with a draft capacity of 180 kN was developed. The two extended octagonal rings were oriented vertically on either side of the tractor drawbar which provided a better match of strain to expected drawbar draft and vertical load than could be achieved with a horizontal orientation in previous designs. Strain distributions in the extended octagonal rings were analyzed using a finite element method to locate optimal strain gage positions to minimize cross sensitivity between draft and vertical force measurements. The DEOR was fabricated from high strength ANSI 4130 steel. Vertical and draft calibrations of the DEOR dynamometer were done in a laboratory universal testing machine. Calibration results show that the DEOR dynamometer had a linearity of 0.99 and negligible cross sensitivity for both horizontal and vertical outputs. The DEOR dynamometer was tested in a field to measure the draft and vertical force of a sweep-type liquid manure injector. No mechanical problems were observed for the dynamometer in the field test and its draft outputs were comparable to those reported in the literature for manure injectors.     

太湖数字流域系统在阳澄湖地区的研究和应用

基于太湖数字流域系统建立了阳澄湖地区一维河网模型,选取研究范围内38个监测断面的水位水质实测资料对模型进行率定,得到河道参数范围:糙率0.020 ～ 0.025,CODCr降解系数0.1 ～0.3 d-1,NH3-N降解系数0.07～0.29 d-1,TP综合沉降系数0.05～0.10d-1,模型拟合结果较好.应用建立的一维河网模型计算阳澄湖地区污染物削减前后的断面水质浓度,结果显示,太湖数字流域系统可定量地进行阳澄湖地区水环境质量的模拟和预测.     

付里叶变换近红外漫反射光谱分析选择标样集的研究

本文以线性代数中向量组极大线性无关组的存在性为理论基础,研究了近红外漫反射光谱定量分析采用主元素法选择定标样品的原理和方法;并以谷子样品为实验材料,在谷子蛋白质含量NIR测定中实施了主元素标样选择的方法;结果表明该方法所选标样集有很大的优点,它以较少的样品可以代表全部待分析样品的信息。     

付里叶变换近红外漫反射光谱法浓度定标方程的研究

本文研究了由光谱数学处理得到的浓度定标方程。研究了定标方程的化学基础和物理基础,指出方程的易变性来源于近红外漫反射光谱的易变性。研究了方程的易变性对NIRDRSA的影响,讨论了评价方程的原则与如何得到预测精度高的定标方程。     

土壤水分时域反射仪(TDR)自制探头的校正与应用

根据TDR工作原理制作了TDR探头,并对其进行了室内标定,结果表明,介电常数的平方根(Ka)与体积含水量(,θ%)有良好的线性相关(R2=0.995)。并在田间与中子仪测定结果进行了对比,结果表明,平均绝对偏差为0.17%,平均相对偏差为8.58%,说明TDR自制探头可以在黄土高原地区推广应用。