配位滴定法同时测定金属离子浓度的研究

将多元校正分析法应用于配位滴定中，以ＥＤＴＡ为滴定剂，玻璃电极为指示电极，饱和甘汞电极为参比电极。依据电位滴定原理，对混合三组分：Ｃｕ￣（２＋）、Ｃｄ￣（２＋）、Ｚｎ￣（２＋）、及Ｃｕ￣（２＋）、ＣＯ￣（２＋）、Ｎｉ￣（２＋）进行测定，各金属离子之间的△ｌｏｇＫ在０．０４～２．３４之间，计算误差一般小于土１０％。     

一种基于时延的水下声基阵坐标估算方法

阵形估算是水听器阵列应用中的关键问题,基于时延的水下声基阵大地坐标标定方法利用声源发射和声阵接收的CW脉冲之间的时延获得空间中的三个声源发射点到阵元的距离,并以这三个声源发射点为圆心,以声源发射点到阵元的距离为半径做球面,得到的交点即为阵元的大地坐标.通过实验数据分析结果可以得出如下结论:基于时延的球面交汇法得到的阵形标定结果的绝对误差均值为0.13 m,可以把该方法运用于实际的工程测量当中.     

商业平板式超滤膜包完整性检验：对海洋胶体生物地球化学研究的启示

The performance and integrity of a cassette cross-flow ultrafilter(Pellicon 2, Millipore) are examined with a suite of macromolecules of different molecular masses. The retention coefficient during the cross-flow ultrafiltration experiments increases with increasing molecular mass and reaches 90% with 10 kDa dextran in both milli-Q water and ultrafiltered seawater media. Based on a 90% retention coefficient, the molecular mass cut-off for the ultrafiltration membrane is defined at 10 kDa, which is ten times(1 kDa) that rated by the manufacturer. To further validate the accuracy of the laboratory calibration, the samples from the lower Zhujiang River and the Jiulong River Estuary are ultrafiltered with the cassette ultrafiltration membrane and the colloidal organic carbon abundances in these samples are quantified with the ultrafiltration permeation model based on time series permeation subsamples. The colloidal organic carbon abundances are 5.8%–21.1% in the Jiulong River Estuary and 5.6%–11.0% in the lower Zhujiang River. These are consistent with the reported values for both estuaries as well as with the colloidal organic carbon abundances in marine environments over the coastal and open oceans with 10 kDa cut-off membranes. Therefore, these field data support the laboratory calibration result and indicate the validity of the experimental and quantification procedure adopted. The discrepancy between the nominal molecular mass cut-off and the actual pore size of the ultrafiltration membrane should be of great concern for research in colloidal and nanoparticle biogeochemistry. Careful examination of the membrane integrity should be taken during ultrafiltration experiments in order to avoid misleading molecular mass cut-off information.     

“重量稀释海水”的误差分析

“重量稀释海水”是检定高精度盐度计的基本方法。本文首先结合实际概述了“重量稀释海水”的方法步骤,然后从理论上对“重量稀释海水”的误差进行了分析研究,给出了最大值和最小值,并通过赋值计算找出了其误差分布规律。最后列举了两个实例说明了该方法的实际应用情况。     

Multibeam Echo Sounders-IMU Automatic Boresight Calibration on Natural Surfaces

ABSTRACT

This paper details a new boresight calibration method for multibeam echo sounder systems This method is based on an automatic data selection algorithm, followed by a boresight least squares adjustment This method, called MIBAC (MultiBeam-IMU Boresight Automatic Calibration), takes in input overlapping survey strips following a simple line pattern over a regular slope. We first construct a boresight error observability criterion, used to select automatically the most sensitive soundings to boresight errors. From these soundings, we perform a 3D adjustment of the boresight angle, thus taking into account the coupling between angles. From a statistical analysis of the adjustment results, we derive the boresight angle precision. Numerical results obtained with four different multibeam echo sounder systems are presented and compared to those of a patch test calibration method. Finally, we demonstrate the performances of MIBAC through a standard deviation along the surface normal approach computed by principal component analysis.     

Monitoring wetland ditch water levels in the North Kent Marshes,UK, using Landsat TM imagery and ground-based measurements

Abstract

An understanding of hydrology is a prerequisite for ensuring the successful management, conservation and restoration of wetland environments. Frequently, however, little is known about historical hydrological conditions, such as water levels, within wetlands. Moreover, many channel and ditch systems in wetlands are not routinely monitored, except perhaps for research purposes. A methodology is presented herein which makes use of satellite imagery to indirectly provide remotely sensed observations of water levels within channels and ditches. Using multi-temporal Landsat Thematic Mapper (TM) imagery and simultaneous ground-based measurements of water levels, statistical relationships are established between satellite-derived effective wet ditch widths and measured water levels in the drainage system of the Elmley Marshes, southeast England. These relationships can be used subsequently to estimate historical ditch water levels and to monitor contemporary ditch water levels in the wetland. The study shows that satellite imagery has much to offer in monitoring changes in the hydrological regime of wetlands and in providing complimentary approaches to field monitoring.     

Probabilistic calibration of a distributed hydrological model for flood forecasting

Abstract

The complexity of distributed hydrological models has led to improvements in calibration methodologies in recent years. There are various manual, automatic and hybrid methods of calibration. Most use a single objective function to calculate estimation errors. The use of multi-objective calibration improves results, since different aspects of the hydrograph may be considered simultaneously. However, the uncertainty of estimates from a hydrological model can only be taken into account by using a probabilistic approach. This paper presents a calibration method of probabilistic nature, based on the determination of probability functions that best characterize different parameters of the model. The method was applied to the Real-time Interactive Basin Simulator (RIBS) distributed hydrological model using the Manzanares River basin in Spain as a case study. The proposed method allows us to consider the uncertainty in the model estimates by obtaining the probability distributions of flows in the flood hydrograph.

Citation Mediero, L., Garrote, L. & Martín-Carrasco, F. J. (2011) Probabilistic calibration of a distributed hydrological model for flood forecasting. Hydrol. Sci. J. 56(7), 1129–1149.     

Prediction and modelling of rainfall–runoff during typhoon events using a physically-based and artificial neural network hybrid model

Abstract

The accurate prediction of hourly runoff discharge in a watershed during heavy rainfall events is of critical importance for flood control and management. This study predicts n-h-ahead runoff discharge in the Sandimen basin in southern Taiwan using a novel hybrid approach which combines a physically-based model (HEC-HMS) with an artificial neural network (ANN) model. Hourly runoff discharge data (1200 datasets) from seven heavy rainfall events were collected for the model calibration (training) and validation. Six statistical indicators (i.e. mean absolute error, root mean square error, coefficient of correlation, error of time to peak discharge, error of peak discharge and coefficient of efficiency) were employed to evaluate the performance. In comparison with the HEC-HMS model, the single ANN model, and the time series forecasting (ARMAX) model, the developed hybrid HEC-HMS–ANN model demonstrates improved accuracy in recursive n-h-ahead runoff discharge prediction, especially for peak flow discharge and time.     

福建测震台网各种类型地震计脉冲标定结果统计与分析

以福建省测震台网现有地震计种类的相关参数为基础,介绍各种地震计使用“十五”标定系统时需设置的脉冲标定参数的计算过程.通过分析“十五”标定系统应用以来的相关处理结果,总结各种类型地震计周期、阻尼、灵敏度的影响因素,从一定程度上反映相关类型地震计的稳定性能.     

微震监测系统标定信号的应用

徐州矿务集团有限公司三河尖煤矿建立了覆盖全矿井的KZ-1型微震监测系统,通过地面监测主机向井下各测站发时间同步校时信号,用GPS秒号起始去同步各个测站下位机时钟,保证了各测站之间相对时间精确度.KZ-1型微震监测系统的拾震器设置了双换能器,且各有一个独立的磁回路,通过地面监测主机向拾震器标定换能器发标定指令信号,信号检测换能器再将输出信号上传至监测主机,实现了即时定量标定.标定信号的应用使KZ-1型微震监测系统具备整个系统检测功能,包括灵敏度、频响特征以及各测站的时间同步误差.