徐州冬季雾霾天气PM1.0单颗粒污染特征分析

本文利用场发射透射电子显微镜(FETEM)及能谱仪(EDS),对2014年元月徐州市区雾霾污染天气下采集的PM1.0进行了单颗粒样本分析.通过电子束辐照损伤实验,分析了无机气溶胶颗粒形态、颗粒模态及颗粒混合态,探讨了复合污染颗粒的形成过程.利用EDS实验,进行了无机气溶胶颗粒物相分析,估算了颗粒相中直接排放源组分及二次污染组分含量.对碱金属及极易挥发的S和N在PM1.0上的富集分布情况进行了分析.实验结果表明:PM1.0直接排放源颗粒与无机水溶性离子组分、可溶有机溶胶组分多呈非均相性内部混合分布特征.采样时段大气环境相对湿度大、温度较低及区域性秸秆焚烧,大量气态污染物凝结或浓缩在直接排放颗粒物表面,造成复合污染颗粒的快速转化,是导致徐州冬季雾霾事件形成的主要原因.     

用光学粒子计数器测颗粒物质量浓度和能见度

2001年夏季和冬季，在北京市大兴区榆垡镇，利用光学粒子计数器、能见度仪和颗粒物质量监测器对近地面大气气溶胶粒子数密度、大气能见度、颗粒物质量浓度(PM10、PM2．5和PM1．0)等进行了联合观测实验，取得了大量相关资料．本文通过对不同尺寸大气气溶胶粒子的数密度与颗粒物质量浓度及大气能见度的多元线性回归分析，给出了利用粒子数密度计算PM10、PM2．5、PM1．0和大气能见度的经验计算公式．     

纳米颗粒物化学成分测量技术及其应用 #br#

纳米颗粒物是大气颗粒物的重要组成部分, 对大气环境、气候变化以及人群健康有着重要的影响。纳米颗粒 物物理化学特性, 特别是化学组成, 在其中起着重要的作用。总结了国内外主要的纳米颗粒物化学成分测量技术, 重 点介绍了不同测量技术的工作原理和相关仪器的典型结构, 并结合大气环境研究中的应用实例, 分析了不同测量技术 的应用范围及优缺点, 最后展望了纳米颗粒物测量技术及应用的发展方向。     

自然通风室内外PM10、PM2.5、PM1.0污染特征

通过建立室内颗粒物集总参数模型,对自然通风房间室内的颗粒物污染特征及室内外颗粒浓度比值进行理论分析和实验研究,结果表明,室内PM10、PM2.5、PM1.0分别有46.7%~54.4%、48.7%~57.3%、22.9%~28.9%来自室内污染,室内外颗粒物的相关性随粒子尺度的增大而增强;测试房间PM1.0的I/O比在0.97~1.31内变化,PM2.5、PM10的I/O分别介于0.90~1.23、0.95~1.08之间,随着粒径的增大I/O比降低,其均值分别为1.09、1.06、1.00。     

基于激光雷达和地面监测数据对南京一次沙尘和细粒子污染时空演变特征的分析

利用偏振激光雷达对南京2015年3月一次沙尘和细粒子污染共存过程的颗粒物垂直分布特征进行观测研究,结合地面气象数据、PM2.5和PM10质量浓度数据、PM2.5组分数据、卫星MODIS测量结果,探讨不同颗粒形态下的气象因素、颗粒物浓度分布、组分特征以及颗粒物光学特性的时间演变和垂直分布特征.结果表明:高湿、弱风等不利气象条件利于二次粒子的生成和累积,期间水溶性组分中SNA(SO₄^2-、NO₃^-、NH₄⁺)等二次组分浓度明显升高;同一时期长距离输入的沙尘发生的沉降对地面PM2.5化学组分构成显著影响,3月21日下午时段至3月22日在1.1².5 km高度的沙尘颗粒物向地面输送造成地面PM2.5的Ca²⁺突然增大到3.2μg/m³;3月22日下午以后在东南气流影响下,地面PM2.5向西扩散,PM2.5颗粒物浓度得到有效稀释,同时段出现了沙尘输入和扬尘过程,扬尘过程和沙尘输入使地面的粗颗粒增多,PM10剧增至347μg/m³;南京与无锡地区的颗粒物时空分布呈现高度相似的变化特点,具有区域性分布特征.后向轨迹分析表明,500 m、800 m及1000 m三个高度气团移动方向基本一致,主要从内蒙、京津冀、山东等地入海,后又经东海返回内陆抵达南京.     

便携式绿色呼吸PM2.5检测净化一体机的设计

目前大气颗粒物已经成为我国大气污染的主要污染物,尤其以PM2.5对于大气环境的影响和人体健康的危害最大。本文以AT89C51单片机为核心,充分调研市场上主要的空气净化技术,采用HEPA网过滤PM2.5颗粒,在检测环境的pm2.5的基础上,可去除空气中的颗粒物,包括过敏原、室内的PM2.5等空气污染问题,为我们的健康保驾护航。     

成都市PM2.5、PM10变化特征及其与气象因素的关系

为研究气象因素对成都市大气细颗粒物 (PM2.5)、可吸入颗粒物 (PM10) 的影响, 收集了2015―2018 年成都市 PM2.5、PM10的月平均浓度, 采用Pearson 相关分析法, 分析了成都市PM2.5、PM10与气象条件的关系。结果表明： (1) 2015 ―2018 年, 成都市PM2.5、PM10年平均浓度虽然年际间差别较小, 但整体呈现逐年缓慢下降趋势, 2015 年以来成都市的 一系列大气污染控制措施是PM2.5、PM10逐年缓慢下降的原因; 2015―2018 年成都市PM2.5、PM10浓度季节变化特征整体 表现为冬季 > 春季 > 秋季> 夏季。(2) 不同气象因素对成都市PM2.5、PM10月平均浓度的影响程度不同, 降水量与气温 是影响成都市PM2.5、PM10月平均浓度的主要因素, 两者与PM2.5、PM10呈较高的负线性相关, 其中PM2.5、PM10与降水量 的相关系数均为 −0.612, 与月平均气温的相关系数分别为 −0.822、−0.776, 降水会通过捕获大气中的颗粒物来去除 PM2.5、PM10, 而温度的升高会加强PM2.5、PM10等污染物在垂直方向上的对流运动, 从而对成都市污染物浓度的降低起 到重要作用; 日照时数、月平均风速、相对湿度等与PM2.5、PM10月平均浓度整体也呈现负相关, 但与降水量和气温相 比, 日照时数、月平均风速与PM2.5、PM10月平均浓度的相关性较低, 而相对湿度与PM2.5、PM10月平均浓度的相关性则 更加微弱, 表明相对湿度的变化对成都市PM2.5、PM10的积累和扩散影响很小。     

成都秋冬季气溶胶消光系数的非平稳性分析

基于对大气消光系数时间序列随机性的深入研究,利用成都市2015至2017年秋冬季的大气能见度、相对湿度(RH)、颗粒物(PM10和PM2.5)质量浓度和NO2含量监测数据,反演得到该区域相应时段的气溶胶消光系数时间序列.基于位置、尺度、形状的广义可加模型检测了气溶胶消光系数时间序列的平稳性,并对气溶胶消光系数序列进行了协变量分析.实验结果表明,成都秋冬季气溶胶消光系数时间序列均为非平稳序列,其均值和方差表现为非线性变化.细颗粒物(PM2.5)质量浓度、RH和气溶胶组分(PM2.5/PM10)均是气溶胶消光系数序列非平稳变化的显著协变量.其中,PM2.5为气溶胶消光系数序列非平稳性最主要的贡献因子,其次为RH,贡献最小的为PM2.5/PM10,且气溶胶消光系数的爆发式增长与PM2.5、RH和PM2.5/PM10的协同作用密切相关.     

基于大数据的天气状况研究

细微颗粒2.5是指大气中直径小于或等于2.5um的颗粒物的每立方米含量。而这些细颗粒物也称为可入肺颗粒物。它们粒径小,富含大量的有毒、有害物质,且在大气中的停留时间长、输送距离远,被称为大气污染的元凶,并且对人体健康有很大危害。文章通过使用数据挖掘方法对某区域某段时间的天气情况和细颗粒物污染状况进行了分析,研究了细颗粒物污染程度与天气状况的关系,得出PM2.5与能见度、风速、露点和湿度负相关。     

合肥地区2013年春节期间PM2.5质量浓度演变特征

利用2013年2月8~19日合肥地区获取的大气颗粒物和常规气象观测资料,依据烟花爆竹燃放、降水过程、相对湿度和风速特点,分析了PM2.5质量浓度在不同气象条件下的变化特征。结果表明:合肥春节期间PM2.5质量浓度平均值为58.3μg/m~3,仅出现两个PM2.5质量浓度污染日;城市居民集中燃放烟花爆竹引起PM2.5质量浓度急剧增大,但主要排放PM1;降水过程对PM2.5质量浓度具有湿沉降作用,过程降水量越大,PM2.5质量浓度湿沉降量越大;PM1、PM1~2.5和PM2.5~10与相对湿度的相关系数分别为0.45、0.26和-0.07,粒径尺度越小的颗粒物吸湿增长特性越显著;PM2.5质量浓度演变与风速呈负相关,两者的相关系数为-0.33,风速越大,越利于颗粒物扩散。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.