便携式拉曼光谱仪测定环氧丙烷含量的研究

环氧丙烷是一种常见的化工原料,具备易燃性和毒性,不同浓度的环氧丙烷可能产生的危害程度和处置方式不同.通过建立一种快速检测定量分析环氧丙烷的方法,利用便携式拉曼光谱仪进行无损检测,应用于样品的定性、定量分析.通过不同浓度的环氧丙烷拉曼光谱特征峰(901 cm-1)结合标准曲线法,绘制标准工作曲线.本方法测定简单、操作方便...     

Adsorption characteristics of Cu and Ni on Irish peat moss

Peat has been widely used as a low cost adsorbent to remove a variety of materials including organic compounds and heavy metals from water. Various functional groups in lignin allow such compounds to bind on active sites of peat. The adsorption of Cu(2+) and Ni(2+) from aqueous solutions on Irish peat moss was studied both as a pure ion and from their binary mixtures under both equilibrium and dynamic conditions in the concentration range of 5-100mg/L. The pH of the solutions containing either Cu(2+) or Ni(2+) was varied over a range of 2-8. The adsorption of Cu(2+) and Ni(+2) on peat was found to be pH dependent. The adsorption data could be fitted to a two-site Langmuir adsorption isotherm and the maximum adsorption capacity of peat was determined to be 17.6 mg/g for Cu(2+) and 14.5mg/g for Ni(2+) at 298 K when the initial concentration for both Cu(2+) and Ni(2+) was 100mg/L, and the pH of the solution was 4.0 and 4.5, respectively. Column studies were conducted to generate breakthrough data for both pure component and binary mixtures of copper and nickel. Desorption experiments showed that 2mM EDTA solution could be used to remove all of the adsorbed copper and nickel from the bed.     

硝酸盐氮,亚硝酸盐氮总量紫外吸收快速测定

水体中尤其是海水中硝酸盐氮的测定较繁琐,干扰物质多,分析时间长,重现性差,准确性不高。文章通过实验介绍一种省时、省力、简便可行不消耗化学试剂且抗氯化物干扰、精度和准确度较高的硝酸盐氮、亚硝酸盐氮总量测定方法。     

曲线拟合在环境空气污染物浓度预测中的应用

从分析环境空气污染物月均值的时间变化规律入手 ,找出与污染物变化特征相对应的数学函数 ,应用曲线拟合的方法 ,结合统计回归分析 ,建立曲线拟合方程。该方程可应用于污染物浓度的中长期预测     

负荷历时曲线法在梁子湖流域污染容量总量控制中的应用

采用负荷历时曲线法(LDC),基于水质保护目标,研究水体纳污能力,确定最大日负荷总量(TMDL)是当前流域污染总量控制的主要方法之一。根据梁子湖高桥河流域控制断面2008~2011年的水文、水质数据,以主要污染物COD为指标,将负荷历史曲线法运用到梁子湖高桥河等子流域污染容量总量控制中,对该流域的最大日负荷(TMDL)变化规律进行分析,提出流域不同水文条件下的污染负荷消减量。研究结果表明:梁子湖水环境受面源污染影响较大。高桥河、徐家港、张家桥港、山坡港、宁港流域,在高流量期实际负荷值均已超出了允许负荷,其削减量分别为61.36、4.33、12.98、3.84、7.13 t/d;徐家港和宁港流域在丰水期实际负荷值也超出了允许负荷,削减量分别为0.16、0.17 t/d。该研究为流域相关管理部门对湖泊水环境的污染控制提供可靠的决策依据。     

改性沸石对2,4-二氯苯酚的去除作用

采用溴化十六烷基三甲铵(HDTMAB)制备改性沸石,在与天然沸石对比的基础上,研究了改性沸石在动态条件下去除2,4-DCP的效果。并对影响去除率的主要因素,包括沸石粒径、进水浓度,进水流速,沸石用量,进水pH值等进行研究。结果表明,细粒改性沸石在pH2.5左右时处理低浓度2,4-DCP溶液时,能取得较好的去除效果,流速较低时去除率最高可达80%以上。     

Nonparametric Monte Carlo Simulation for Flood Frequency Curve Derivation: An Application to a Korean Watershed1

Abstract: A mix of causative mechanisms may be responsible for flood at a site. Floods may be caused because of extreme rainfall or rain on other rainfall events. The statistical attributes of these events differ according to the watershed characteristics and the causes. Traditional methods of flood frequency analysis are only adequate for specific situations. Also, to address the uncertainty of flood frequency estimates for hydraulic structures, a series of probabilistic analyses of rainfall‐runoff and flow routing models, and their associated inputs, are used. This is a complex problem in that the probability distributions of multiple independent and derived random variables need to be estimated to evaluate the probability of floods. Therefore, the objectives of this study were to develop a flood frequency curve derivation method driven by multiple random variables and to develop a tool that can consider the uncertainties of design floods. This study focuses on developing a flood frequency curve based on nonparametric statistical methods for the estimation of probabilities of rare floods that are more appropriate in Korea. To derive the frequency curve, rainfall generation using the nonparametric kernel density estimation approach is proposed. Many flood events are simulated by nonparametric Monte Carlo simulations coupled with the center Latin hypercube sampling method to estimate the associated uncertainty. This study applies the methods described to a Korean watershed. The results provide higher physical appropriateness and reasonable estimates of design flood.     

深圳市新一代暴雨强度公式的研制

首先构造了深圳市新一代暴雨强度公式研制的路线图，重点是利用深圳市气象局1954-2003年50年间的暴雨记录，用指数分布和P-Ⅲ分布进行分布曲线拟合和选优，得到了理论上的雨强-历时-重现期三联表，在此基础上再分别采用最优法、二分搜索法和广义逆法等3种方法求解分公式和总公式参数，根据误差最小的原则确定最优方法。结果表明：由指数分布拟合分布曲线，经过上述步骤求解得到的公式参数，误差最小，符合相关国标要求。     

EFFECT OF ORIENTATION OF SPATIALLY DISTRIBUTED CURVE NUMBERS IN RUNOFF CALCULATIONS1

ABSTRACT: The NRCS curve number approach to runoff estimation has traditionally been to average or “lump” spatial variability into a single number for purposes of expediency and simplicity in calculations. In contrast, the weighted runoff curve number approach, which handles each individual pixel within the watershed separately, tends to result in larger estimates of runoff than the lumped approach. This work proposes further enhancements that consider not only spatial variability, but also the orientation of this variability with respect to the flow aggregation pattern of the drainage network. Results show that the proposed enhancements lead to much reduced estimates of runoff production. A revised model that considers overland flow lengths, consistent with existing NRCS concepts is proposed, which leads to only mildly reduced runoff estimates. Although more physically‐based, this revised model, which accounts directly for spatially distributed curve numbers and flow aggregation, leads to essentially the same results as the original, lumped runoff model when applied to three study watersheds. Philosophical issues and implications concerning the appropriateness of attempting to disaggregate lumped models are discussed.     

旅行成本法在我国应用中存在的几个问题

我国旅行成本法案例研究多数未分清旅行成本与旅游目的地本身价格的关系,推导的游憩需求曲线是旅行成本-旅游人次模型,而不是旅游目的地本身的价格-旅游人次需求曲线。文章具体说明了区域旅行成本法的基本原理及操作方法,并用乔光华文章数据重新对达里诺尔国家级自然保护区游憩价值进行计算,对旅行成本的构成等问题进行了讨论,得出其消费者剩余为0.9221×108元a/,比原研究中的0.0937×108元a/高出近10倍。认为乔光华等的研究在推断游憩需求曲线时存在方法上的问题,直接将旅行成本和时间价值作为游憩价值不符合旅行成本法的基本原理和公共物品无(或低)市场价格的经济理论。还对调整后的旅行成本数据进行了计算,得到保护区游憩价值为1.3581×108元a/。