Isotopenhydrogeologische Untersuchungen Im Bacho-Delta (Vietnam)

Abstract

Abecarnil is a β-carboline with high affinity to benzodiazepine receptors. Synthesis and spectral data of the title compound are presented. [¹³C₃]. Abecarnil was synthesized in a five step synthesis. [¹³C₂]Glycine-isopropylester-hydrochloride was condensed with p-methoxy-benzaldehyde to give N-(p-methoxy-benzyliden)-[¹³C₂]glycine-isopropyl-ester. Further reaction with 5-benzyloxy-pseudogramine and the introduction of [¹³C]formaldehyde in a Pictet-Spengler reaction yielded the intermediate 1,2,3,4-tetrahydro-β-carboline derivative. The following dehydration led to [¹³C₃]Abecarnil in an overall yield of 23%     

Радиометричесĸий азимутальный зонд

Es werden technologische Untersuchungen zum Herstellungsprozeβ von Zink- und Bleioxiden unter Verwendung von radioaktiven Tracern beschrieben, die die Verbesserung der technischen Anlagen und der Qualität der Endprodukte zum Ziel hatten.     

分布式冰雪融水雨水混合水文模型

在以冰雪融水雨水混合补给为主的流域中，产流空间分布的不均匀性十分突出。为此，建议一种基于数字高程模型（DEM）和地理信息系统（GIS）的网格式空间分布水文模型。该模型可在分别考虑不同网格的热量和水分状态的基础上计算产流和汇流，并在乌鲁木齐河山区流域上得到应用，取得了良好效果。     

River basin landscape pattern and its modern earth surface process of the LRGR

Directing at the the longitudinal rangegorge region＇s special constituting condition of river basin geography landscape, the authors synthetically used the data analyses and spatial information treatment technique, selected corresponding measurable homology indicators, comparatively analyzed the characteristic difference of different river basin＇s landscape constitution patterns in the longitudinal range-gorge region, researched into different river net patterns and land cover conditions of each river basin landscape, and explored the river basin＇s landscape form and its spatial distributed chracters. Based on the analyses on river basin＇s landscape composition and its spatial distribution characters, this study researched into the main driving factor of modern earth surface process in the longitudinal range-gorge region, analyzed the relationship between the basin landscape changing and its modern earth surface process, finally completed a series of the potential ecological hydrology effect analyses.     

Numerical simulation of three-dimensional saturated flow in randomly heterogeneous porous media

This paper presents a numerical method for simulating flow fields in a stochastic porous medium that satisfies locally the Darcy equation, and has each of its hydraulic parameters represented as one realization of a three-dimensional random field. These are generated by using the Turning Bands method. Our ultimate objective is to obtain statistically meaningful solutions in order to check and extend a series of approximate analytical results previously obtained by a spectral perturbation method (L. W. Gelhar and co-workers). We investigate the computational aspects of the problem in relation with stochastic concepts. The difficulty of the numerical problem arises from the random nature of the hydraulic conductivities, which implies that a very large discretized algebraic system must be solved. Indeed, a preliminary evaluation with the aid of scale analysis suggests that, in order to solve meaningful flow problems, the total number of nodes must be of the order of 10⁶. This is due to the requirement that x _i gl _i L _i , where x _i is the mesh size, _i is a typical correlation scale of the inputs, and L _i is the size of the flow domain (i = 1, 2, 3). The optimum strategy for the solution of such a problem is discussed in relation with supercomputer capabilities. Briefly, the proposed discretization method is the seven-point finite differences scheme, and the proposed solution method is iterative, based on prior approximate factorization of the large coefficient matrix. Preliminary results obtained with grids on the order of one hundred thousand nodes are discussed for the case of steady saturated flow with highly variable, random conductivities.     

甘肃省国家水文数据库系统简介

甘肃省国家水文数据库的建设是我省水文现代化建设的一项重要内容,该库的建成,可为我省防汛、抗旱提供优质、全方位、多功能的服务。本文从“系统配置”和“系统功能”两部分对该库进行了介绍     

Geomorphic impacts of timber harvesting

Timber harvesting influences (a) forest hydrology; (b) fluvial geomorphology; (c) terrain stability; and (d) integrated watershed behavior. Impacts on forest hydrology are well understood and include increased average runoff, total water yield, increased storm runoff and advances in timing of floods. Stream channels and valley floors are impacted differently by fine sediment, coarse sediment and large woody debris transport. Terrain stability is influenced through gully and mass movement processes that are accelerated by timber harvesting. Impacts on integrated watershed behavior are assessed through disturbed sediment budgets and lake sediments.     

水文水资源中不确定性的信息熵分析方法综述

介绍了信息熵的简要历史与基本概念,然后详细综述了它在水文分布的生成、参数估计、水文预报、水文站网规划及降雨分布等方面的应用。     

基于BP神经网络的山坡平均坡度解

用BP神经网络方法对山坡平均山坡的解法进行分析,以29个小流域样本的水文数据为基础,通过应用人工神经网络反向传播BP(Back Propagation)算法,引入与山坡平均坡度密切相关的流域影响因子,并且通过调整网络结构中的权因子和阈值,建立了山坡平均坡度与流域影响因子之间的BP网络模型.计算结果表明,用拓扑结构为5-12-1的BP网络,经过学习150000次后,随机测试小流域样本的山坡平均坡度其计算结果和测试结果的相对误差不超过5%;证明该ANN模型的拟合能力强,从而为小流域山坡平均坡度的计算提供了一条新途径.     

Isotopic composition of bottled water in Saudi Arabia

The ¹⁸O/¹⁶O and ²H/¹H ratios of 18 water brands representing the most popular bottled water brands in the Saudi market were measured using a system based on the latest advancements in tunable off-axis integrated cavity output diode laser spectroscopy (OA-ICOS) in the near-infrared spectral region. Utilizing δ¹⁸O and the δ²H values of locally produced water samples, a meteoric water line (δ²H?=?7.84 δ¹⁸O?+?2.11) was extracted and found to be consistent with the slope of the global meteoric water line (GMWL) and the geographic location of Saudi Arabia.