人工神经网络在湖泊富营养化评价中的应用研究

运用人工神经网络技术评价湖泊富营养化程度。详细阐述了神经网络的结构设计，样本生成及学习算法，给出了通过训练得出的网络权和阈值，最后将此神经网络用于１２个湖泊的富营养化评价，取得了较好的评价结果。     

三氯卡班可以影响肾小管上皮细胞的屏障功能

三氯卡班(TCC)是一种被广泛应用于个人护理用品中的广谱型亲脂性杀菌剂,已在多种环境介质和生物体中检出。因其潜在的环境蓄积、生物累积和生物毒性效应,日益受到学者们的关注。借助TCC对NRK-52E(大鼠肾小管上皮细胞)的毒性暴露实验,通过检测细胞活力、以及与跨膜电阻和紧密连接相关的连接黏附分子1(JAM~(-1),junctional adhesion molecule 1)的蛋白表达水平,研究了TCC潜在的肾脏毒性效应。结果显示,10μmol·L~(-1)TCC处理48 h时培养细胞呈现不规则的集落;10μmol·L~(-1)和20μmol·L~(-1)TCC处理NRK-52E 24 h、48 h和72 h后可以显著抑制细胞生长;3.57μmol·L~(-1)TCC(生长抑制的48 hIC20)处理NRK-52E 48 h可以显著抑制细胞间紧密连接蛋白JAM~(-1)的表达量,并降低跨膜电阻,影响肾脏的屏障功能。本研究的结果能够为进一步揭示TCC对动物的毒害机制、评估其对动物的健康风险提供数据支持。     

Competition for electrons between reductive dechlorination and denitrification

It is common that 2,4,6-trichlorophenol (TCP) coexists with nitrate or nitrite in industrial wastewaters. In this work, simultaneous reductive dechlorination of TCP and denitrification of nitrate or nitrite competed for electron donor, which led to their mutual inhibition. All inhibitions could be relieved to a certain degree by augmenting an organic electron donor, but the impact of the added electron donor was strongest for TCP. For simultaneous reduction of TCP together with nitrate, TCP’s removal rate value increased 75% and 150%, respectively, when added glucose was increased from 0.4 mmol?L^–1 to 0.5 mmol?L^–1 and to 0.76 mmol?L^–1. For comparison, the removal rate for nitrate increased by only 25% and 114% for the same added glucose. The relationship between their initial biodegradation rates versus their initial concentrations could be represented well with the Monod model, which quantified their half-maximum-rate concentration (K _S value), and K _S values for TCP, nitrate, and nitrite were larger with simultaneous reduction than independent reduction. The increases in K _S are further evidence that competition for the electron donor led to mutual inhibition. For bioremediation of wastewater containing TCP and oxidized nitrogen, both reduction reactions should proceed more rapidly if the oxidized nitrogen is nitrite instead of nitrate and if readily biodegradable electron acceptor is augmented.

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Simulation of dam/levee-break hydrodynamics with a three-dimensional implicit unstructured-mesh finite element model

Dam failures usually cause huge economic and life losses , especially in urban areas where there is a high concentration of inhabitants and economic actors. In order to understand the physical mechanisms of the formation and development of dam-break flooding, lots of efforts have been put into different types of modelling techniques. However, most of existing models are 1D (one-dimensional) or 2D models based on the shallow water equations. In this paper, we present a 3D numerical modelling investigation of dam-break flow hydrodynamics in an open L-shape channel. A newly developed 3D unstructured mesh finite element model is used here. An absorption-like term is introduced to the Navier–Stokes equations in order to control the conditioning of the matrix equation in the numerical solution process and thus improve the stability. A wetting and drying algorithm is used here to allow the free surface height to be treated with a high level of implicitness and stability. The 3D model has been validated by comparing the results with the published experimental data. Good agreement has been achieved at six selected locations. This study shows that the 3D unstructured mesh model is capable of capturing the 3D hydraulic aspects and complicated local flows around structures in simulation of dam-break flows.     

呼和浩特市大气气相和颗粒物中有机污染物的定性分析

选用聚氨基甲酸酯泡沫塑料吸附块和玻璃纤维滤膜构成的大气全态采样头,以内蒙古四子王旗摹为对照点,于冬夏两季捕集呼和浩特市（呼市）大气气相和颗粒物中的有机污染物,样品经提取分离后用色质联机,气相色谱仪,液相色谱仪鉴定出３类（烃类、芳在,酞酸酯类）近８０种有机污染物,对其中４５种进行定量分析,结果表明呼市地区属于大气有机污染物高浓度地区。     

闽南地区生态环境对酸沉降的临界负荷研究

报道了闽南生态环境对酸沉降临界负荷的研究结果。考虑到干、湿２种沉降形式,试用了１种新的酸沉降临界负荷计算方法:用树木和农作物的SO₂容量代表酸性干沉降的临界负荷,用土壤酸缓冲容量计算酸性湿沉降的临界负荷。结果表明:闽南的干、湿酸沉降临界负荷均大大高于现实酸沉降负荷      

厦门春季气溶胶特征初探

1993年春季对厦门市大气气溶胶进行了研究,其中包括对3种不同粒径的气溶胶质量浓度?气溶胶元素浓度?气溶胶离子浓度?气溶胶酸度和酸化缓冲能力的研究?结果表明:厦门大气气溶胶质量浓度接近于国家一级标准,细粒子的气溶胶的贡献较高;气溶胶中元素含量较高的为Ca,Al,Fe和S等;在厦门地区气溶胶中NH+₄和SO2-₄主要分布在细粒子中,Ca2+和Mg2+则多分布在粗粒子中,并且其值远小于华南地区;气溶胶中细粒子的酸性大于粗粒子,且酸化缓冲能力远低于粗粒子。      

锅炉烟气脱硫技术发展综述

在调查研究的基础上，论述国内外烟道气脱硫技术的发展与前景，提出开发生产适合我国国情的烟气脱硫技术势在必行。还简要介绍了最为普遍的石灰／石灰石法脱硫基本原理。     

塔克拉玛干沙漠北部全新世环境演变(Ⅰ)

通过对塔克拉玛干沙漠北部，塔里木河泛滥平原典型剖面的沉积物粒度特征、化学元素的变化和沉积相特征的研究，并结合＾１４Ｃ测年、揭示了本区域全新世以来的环境变化规律，本区全世以来的多风、高温、干燥的气候形成是以全球气体波为背景，叠加内陆干旱封闭贫地影响而成的，但在干燥气条件下曾有过几次空气湿度较大的偏湿期，本区沉积相主要以充冲积作用形成的粘土层和风力作用下的风砂层为主，剖面中的亚粘土与现代河流相特征一致     

用二氧化氯降解废水中的苯胺类化合物（2）──降解机理的探讨

本文在上文（１）的基础上，进一步研究了经二氧化氯处理前后ＢＯＤ＿５／ＣＯＤ的变化规律，其比值大于或接近０．３．其降解产物有醌及醌的氧化产物和ＮＨＩ．对苯胺及二氧化氯来说其．反应级数为１，整个反应为二级反应．