武汉秋季灰霾和非灰霾天气细颗粒物PM_(2.5)中水溶性离子的特征

分析了武汉地区武大和天虹2个采样点秋季灰霾和非灰霾天气细颗粒物PM2.5中的9种水溶性离子(F-、Cl-、NO3-、SO42-、Na+、NH4+、K+、Mg2+、Ca2+)浓度。结果表明,NO3-、SO42-和NH4+是武汉秋季PM2.5中最重要的3种水溶性离子,且PM2.5中各水溶性离子之间组成比例相对稳定;灰霾期PM2.5中水溶性离子比例的增大是武汉秋季灰霾污染的重要特征,它们可能来源于生物质燃烧、土壤扬尘、化石燃料燃烧、汽车尾气排放等过程,其中天虹站点的大气二次污染比武大站点的严重,固定源对武汉2个站点秋季灰霾期大气中NOx与SO2相对贡献均比非灰霾期的大,移动源对天虹站点秋季大气中NOx与SO2的相对贡献则比武大站点的大。     

保定市区2013年环境空气质量状况及污染原因分析

对保定市6个环境监测国控点2013年的SO2、NO2、PM10、PM2.5监测数据,按时间段进行了统计分析,结果表明:4种空气污染物季节性污染特征明显,月均浓度在采暖期比非采暖期有显著增加;由于受到燃煤及不利气象条件影响,SO2、NO2月浓度变化曲线呈现冬季高、夏季低的"U"字型分布,采暖期SO2浓度约为非采暖期的3倍。PM10、PM2.5浓度全年波动比较频繁,较大浓度值出现在冬季采暖期。沙尘、扬尘天气和秸秆焚烧对春秋季PM10、PM2.5浓度有贡献。     

陕西省榆林市冬季PM_(10)和PM_(2.5)的污染特征

为了探讨陕西省榆林市冬季大气颗粒物的污染特征,2013年11月对榆林市3个采样点进行可吸入颗粒物(PM10)和细颗粒物(PM2.5)同步观测,利用离子色谱法和热光分析法测定PM10和PM2.5中无机水溶性离子和碳组分的浓度。结果表明:3个采样点PM10和PM2.5日均质量浓度分别为162、74μg/m3,颗粒物浓度由大到小的采样点为环保旧站、实验中学和环保大厦;PM10中有机碳和元素碳的质量浓度空间分布与颗粒物的相同;PM2.5中有碳组分在环保旧站和实验中学的浓度接近,都大于环保大厦的;无机离子中SO42-和Ca2+浓度最大;PM10与PM2.5整体偏碱性,亏损的阴离子主要是CO32-;扬尘在PM10中的比例远远大于其他组分;PM2.5中碳组分含量较大,其次是土壤尘、硫酸盐、氯化物和硝酸盐等;治理PM10和PM2.5污染应以加强扬尘控制和减少燃煤污染物排放为主。     

西安市餐饮业大气颗粒物浓度与碳气溶胶研究

为了了解西安市餐饮业大气颗粒物浓度和分布特征,利用安德森8级撞击采样器采集6家不同餐馆颗粒物样品,并用热光碳分析仪对其中的碳气溶胶进行了分析。结果表明:6家餐馆中,面庄、火锅店和韩国菜馆中颗粒物质量浓度较大,烤肉店中有机碳质量浓度最大,并且有机碳与PM1.1的质量浓度比值为99%,其他烹饪方式的有机碳占颗粒物的比例小于20%;餐馆室内大气颗粒物粒径分布呈双峰模式,主峰集中在小于1.1μm范围内,以PM1.1为主;有机碳粒径分布呈单峰模式,集中在0.43~0.65μm范围内。     

福州城区道路大气PM10单颗粒形貌分析

本文应用扫描电子显微镜-能谱仪(SEM-EDX)技术分析福州城区道路大气中PM10颗粒物的形貌特征、粒径分布和元素组成。研究表明,福州城区道路大气中PM10颗粒物形貌多样,以小于0.5μm的细粒子为主,粒子数量随着粒径增大而减少。大气颗粒物类型主要有烟尘集合体、飞灰颗粒、矿物颗粒、生物颗粒等。福州城区道路大气颗粒物污染以化石燃料燃烧、土壤扬尘、机动车尾气为主,海盐气溶胶对福州城区细颗粒物影响不大。     

PM2.5颗粒物采样器校准装置设计及技术关键

正一、研究的目的意义PM2.5是指大气中直径小于或等于2.5微米的颗粒物,也称为可入肺颗粒物,也将PM2.5等同于气溶胶。所谓的气溶胶、细颗粒物其实就是指大气中直径小于或等于2.5微米的细颗粒物,简称PM2.5。虽然PM2.5只是地球大气成分中含量很少的组分,但它对空气质量等有重要的影响。研究表明,颗粒越小对人体健康的危害越大。气象专家和医学专家认为,由细颗粒物造成的灰霾天气对人体健康的危害甚至要比沙尘暴更大。粒径10微米以上的颗粒物,会被挡在人的鼻子外面;粒径在2.5微     

大气腐蚀环境对四川电网输变电设备腐蚀的影响研究

主要对造成金属腐蚀的气象因素和大气污染物进行归纳分析,试图为四川地区电网防腐蚀后续工作提供一定的理论指导。其中气象要素包含相对湿度、表面润湿时间、降雨和温度;污染因子主要为SO2,氮氧化物、Cl-及其他气体、固体颗粒物等。同时针对四川地区具体气候条件和环境情况,分析指出:相对湿度和SO2是影响四川地区大气腐蚀最主要的因素,大气相对湿度增大导致金属表面容易形成薄液膜,提供了大气污染物与金属发生腐蚀反应的有利条件,从而加速金属的腐蚀破坏。     

聊城市交通干道大气污染水平及影响因素分析

为研究交通源空气污染状况，通过采用自动监测系统，于2012年1月至9月期间，对聊城市交通干道东昌路和柳园路附近大气中SO2、NO2、PM10和CO的浓度进行了监测。结果表明：监测期间所有监测点SO2、NO2、PM10和CO的日均值均未超标，能满足《环境空气质量标准》中二类区的标准要求；在所有监测点位，PM10均是首要污染物，污染分担率分别占了43．8％和45．7％；由污染负荷比知，东昌路和柳园路两交通干道的空气污染水平相当。     

秦兵马俑博物馆陶器库房冬季室内空气质量初步研究

于2008年1月30日～3月3日,在秦始皇兵马俑博物馆陶器库开展了室内大气环境调查,同步采集了大气悬浮颗粒PM2.5和NH3样品,获得了PM2.5颗粒中的离子组成,并实时监测了SO2、NOx的浓度变化。结果表明,陶器库中PM2.5平均质量浓度为76.1μg/m3,室外PM2.5平均质量浓度为153.9μg/m3,约为室内浓度的2倍。室内PM2.5中水溶性离子主要由SO42-、NO3-和NH4+组成,平均质量浓度分别为17.5、5.2、5.5μg/m3,它们分别占PM2.5质量浓度的19.7%、5.2%、5.8%。库内NH3平均浓度为4.8μg/m3,室外NH3平均浓度6.6μg/m3,约为室内的1.4倍。室内NO、NO2、NOx浓度日平均分别为4.8×10-9、3.2×10-9、8.0×10-9,SO2浓度日平均为0.9×10-9。研究表明,库内人为活动量对质量浓度、离子浓度和污染气体均有一定影响,库房相对于室外对阻挡颗粒物减少外界影响方面对文物有一定的保护作用,但在阻隔空气污染物和恒温恒湿方面的作用还有待加强。     

复合污染致霾效应研究取得进展

正中国科学院生态环境研究中心等单位承担的中科院"大气灰霾追因与控制"专项和国家自然科学重点基金等项目在复合污染致霾效应的研究中取得进展,揭示了大气中矿尘和氮氧化物(NO=NO+NO)对x 2PM2.5主要成分硫酸盐形成的促进作用,相关研究成果近日发表于Nature出版集团的Scientific Reports。     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.     

空压机轴承箱蜗壳温度探头油封改造

由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。     

Characteristics of mechanical properties of materials in studies of conditions of attainment of marginal states

It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle.     

Determination of parameters of microstructural inhomogeneity of deformation of metals by the method of modeling

The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991.     

水三相点复现的不确定度评定

水三相点是开尔文热力学温度的唯一基准点，也是ITS-90国际温标重要的定义固定点。因此，水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来，中国计量科学研究院研制出一系列高质量的水三相点容器，加强了水三相点的研究，为不确定度的分析提供了更为可靠的实验依据。同时，不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此，根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明，其扩展不确定度为0．16mK(k=2．69，P=0．99)。