基于显微图像处理PM2.5尺寸的分布研究

了解大气中PM2.5颗粒物的大小分布对人体健康的影响有重要意义,本文中分析了大气颗粒物的图像特征,图像的识别和处理方法,用提取颜色通道、直方图均衡化、有选择保边缘平滑、开闭操作以及阈值分割等处理,分割图像中的颗粒,并有效地识别和分类颗粒物的大小;并在Image-Pro Plus 4.0(IPP)软件平台上实现了这一图像处理过程,这种处理和识别方法为PM2.5和其他微米、亚微米颗粒材料的图像分析提供了参考.     

PM2.5规律性漂负值分析

PM2.5粒径的悬浮物特别容易受气象条件影响,尤其湿度和风力影响,当湿度增加,PM2.5沉降,反之,悬浮。风力作用下已凝聚的颗料会分解,由于粒径变小更易悬浮造成持续性的污染。因此,对PM2.5监测技术的掌握和异常数据分析处理变的尤为重要。故对PM2.5其进行实验性监测,观察周围环境对PM2.5的影响,在实验过程中发现规律性负值现象,对此现象进行原因查找及分析。     

基于显微观测及图像处理的颗粒检测综述

本文对粉体颗粒的检测方法进行总结回顾 ,分析了各种方法的技术特点和局限性。针对颗粒特性 ,对基于显微观测与图像处理的粉体颗粒分析检测技术做了研究介绍 ,分析了此技术的现状与发展及应用前景。     

家用PM2.5检测仪

为了使居民方便快捷的了解居住环境的PM2.5情况,设计了一套家用PM2.5检测仪。该检测仪由PM2.5数据采集电路采集室内PM2.5的浓度值,并由微控制器分析处理数据,最后由液晶显示屏显示相应的结果。小巧便携的家用PM2.5检测仪可为人们对于应对雾霾等问题提供检测方案。     

流动颗粒显微图像测量技术研究

针对显微环境下流动颗粒测量的需要,构建了测量平台,研制了基于MEMS工艺的测量器件。在分析流动颗粒显微图像特征的基础上,提出了基于颗粒运动特性的图像测量流程,其中提出了基于基准桢差分的目标提取算法,解决了流动颗粒目标分割的问题,根据图像运动模糊的退化模型,研究了图像模糊恢复的问题。最后以润滑油中的磨损颗粒为例,验证了该文的分析方法对流动颗粒检测的有效性。     

杭州市下沙地区PM2.5浓度监测与分析

利用便携式的空气质量检测仪,对杭州市下沙地区五条道路及三个小区进行了PM2.5的测量.2010年下沙道路PM2.5的质量浓度在40～136μg/m3,2012年道路PM2.5为18～67μg/m3,说明下沙地区空气质量近年得到改善.同时还对不同空间分布的道路与小区空气质量进行了对比,五条道路按空气质量由好到坏依次为:沿江边的之江东路、高教园学源街、靠近商业区文渊路、途经高架桥的学林街以及靠近工业区的围垦街.三个小区空气质量由好到坏依次为:居住密集区内的小区、高教园周边小区、商业区周边小区.分析了影响PM2.5的因素,认为道路上汽车排放的尾气是小区的污染源之一,而天气因素对PM2.5的多寡有很大影响.     

基于显微观测及图像处理的颗粒检测综述

本文对粉体颗粒的检测方法进行总结回顾，分析了各种方法的技术特点和局限性。针对颗粒特性，对基于显微观测与图像处理的粉体颗粒分析检测技术做了研究介绍，分析了此技术的现状与发展及应用前景。     

显微环境下运动颗粒图像测量系统研究

针对运动颗粒测量的需要,确立了测量原理,研制了检测芯片.重点分析了显微环境下颗粒成像的各种光学性能,包括系统的基本参数,系统动态成像性能,景深以及检测芯片对颗粒成像的影响,在此基础上,本文总结了运动颗粒检测系统的光学设计要求,并给出了运动颗粒的图像测量平台的配置.     

显微环境下运动颗粒图像测量系统研究

针对运动颗粒测量的需要,确立了测量原理,研制了检测芯片。重点分析了显微环境下颗粒成像的各种光学性能,包括系统的基本参数,系统动态成像性能,景深以及检测芯片对颗粒成像的影响,在此基础上,本文总结了运动颗粒检测系统的光学设计要求,并给出了运动颗粒的图像测量平台的配置。     

PM2.5与红绿灯

随着2011年岁末北京以及中国中东部频频出现的阴霾天气,“PM2．5”飞蹿成为一个令人揪心的新闻热词。PM2．5是指大气中直径2_5微米以下的可入肺颗粒物,对健康危害极大。在美国,每年因PM2．5致病的死亡人数在五六万人,与交通事故致死的人数相当。而在北京这样的簸箕式地形,一遇无风的阴霾天,PM2．5的浓度远远高于世界其他大都市。PM2．5主要来自机动车排放、燃煤排放、建筑工地扬尘。针对汽车排放中PM2．5．北京将提前采用“国5”严厉排放标准;加速旧车报废;推广新能源车等。然而,治理PM2．5不光是环保部门的事,而是一个系统工程。     

室内PM2.5浓度标准的探讨

PM 2.5在室内颗粒物中占有很大比例,由于具有比表面积大的特点,对多种有机物具有较强的吸附能力,可以直接进入肺泡,导致年总死亡率、心肺疾病死亡率以及肺癌死亡率的增加,对人体产生全方位的影响。所以将PM 2.5纳入我国室内空气质量检测范围和评价体系是加强空气污染防治、保障人体健康的必然要求。通过分析一些国家和国际组织的PM 2.5标准、我国《环境空气质量标准》及室内PM2.5的检测标准,对我国《室内空气质量标准》中PM2.5的浓度标准值进行探讨,为室内PM 2.5浓度的控制提出明确的目标与方向。     

PM2.5监测仪检测用国家一级标准物质的研制

介绍了细颗粒物PM2.5监测仪检测用国家一级标准物质(标物号:GBW13642～GBW13649)的研制方法。用球形度好的单分散交联聚苯乙烯微球作为标准物质候选物,采用可溯源至国家长度基准的测量方法(扫描电子显微镜和图像分析法)及密度测量等方法为标准物质定值;利用经典气溶胶动力学当量直径计算方法,对其空气动力学直径进行建模分析。实验验证:该标准物质适用于PM2.5监测仪切割特性的检测校准以及作为尘源用于PM2.5监测仪量值的检测与校准。     

Coagulation and Collection of PM2.5 Based on a Stack Coagulator

China recently put forward stronger requirements for PM2.5 emission in 2012. Electrostatic precipitators have relatively low efficiency for the collection of submicron particle, especially for PM2.5. An alternate way to increase its efficiency is to enforce the coagulation and, thereby, form larger particles. In this work, we propose an efficient way to enhance the coagulation between oppositely charged particles by using a stack coagulator. Firstly, in order to explore the impact of the bipolar charging and coagulation to the separation efficient of PM2.5, we use system modeling and simulation to explore the whole charge-coagulation-collection process of PM2.5. The results show that the coagulation rate of bipolarly charged particles can be increased by a factor of 10² ～ 10⁴ compared to the neutral particles and the collection efficiency of dust particles increases as the particle size grows. Subsequently, via the dust particles coagulation experiments, the emission rate chart and emission reduction charts of PM2.5 are plotted, which indicate that the average emission reduction of PM2.5 is almost 85%.     

空气中PM2．5颗粒形成过程初探

文章主要研究了黑色金属冶炼及压延加工业PM2．5的排放特征,采用ELPI（Electrical Low Pressure Impactor）静电低压撞击器对烟气中的颗粒的粒数分布及质量浓度分布进行在线分析,通过自动烟尘测试仪采集样品,并对颗粒物的形貌、聚集特性、化学组分及物相组成等进行了深入研究,为中国工业排放PM2．5颗粒的来源分析及PM2．5对健康、气候的影响提供了有力的数据依据。     

Cleanable Air Filter Transferring Moisture and Effectively Capturing PM2.5

The lethal danger of particulate matter (PM) pollution on health leads to the development of challenging individual protection materials that should ideally exhibit a high PM_2.5 purification efficiency, low air resistance, an important moisture‐vapor transmission rate (MVTR), and an easy‐to‐clean property. Herein, a cleanable air filter able to rapidly transfer moisture and efficiently capture PM_2.5 is designed by electrospinning superhydrophilic polyacrylonitrile/silicon‐dioxide fibers as the adsorption–desorption vector for moisture‐vapor, and hydrophobic polyvinylidene fluoride fibers as the repellent components to avoid the formation of capillary water under high humidity. The desorption rate of water molecules increases from 10 to 18 mg min^?1, while the diameters of polyacrylonitrile fibers reduce from 1.02 to 0.14 µm. Significantly, by introducing the hydroxyl on the surface of polyacrylonitrile nanofibers, rapid adsorption–desorption of the water molecules is observed. Moreover, by constructing a hydrophobic to super‐hydrophilic gradient structure, the MVTR increases from 10 346 to 14 066 g m^?2 d^?1. Interestingly, the prepared fibrous membranes is easy to clean. More importantly, benefiting from enhanced slip effect, the resultant fibrous membranes presented a low air resistance of 86 Pa. A field test in Shanghai shows that the air filter maintains stable PM_2.5 purification efficiency of 99.99% at high MVTR during haze event.     

改进的快速跟踪回声状态网络及PM2.5预测

针对递归最小二乘回声状态网络在噪声环境中预测精度不高的问题,提出了一种改进的快速跟踪回声状态网络。首先在递归最小二乘回声状态网络结构的基础上,将自适应调节的可变遗忘因子加入其代价函数中,用改进的递归最小二乘法对网络输出权值进行训练,得到快速跟踪回声状态网络;然后利用经典Lorenz混沌系统验证快速跟踪回声状态网络的有效性;最后利用灰关联法分析各相关变量与PM2.5的关联度,建立PM2.5浓度值辅助变量集合,将辅助变量集合输入到快速跟踪回声状态网络进行PM2.5浓度值预测。实验表明,与传统回声状态网络、递归最小二乘回声状态网络预测效果相比,快速跟踪回声状态网络的预测方法精度佳,抗噪声能力强。     

COVID19: Forecasting Air Quality Index and Particulate Matter (PM2.5)

Urbanization affects the quality of the air, which has drastically degraded in the past decades. Air quality level is determined by measures of several air pollutant concentrations. To create awareness among people, an automation system that forecasts the quality is needed. The COVID-19 pandemic and the restrictions it has imposed on anthropogenic activities have resulted in a drop in air pollution in various cities in India. The overall air quality index (AQI) at any particular time is given as the maximum band for any pollutant. PM2.5 is a fine particulate matter of a size less than 2.5 micrometers, the inhalation of which causes adverse effects in people suffering from acute respiratory syndrome and other cardiovascular diseases. PM2.5 is a crucial factor in deciding the overall AQI. The proposed forecasting model is designed to predict the annual PM2.5 and AQI. The forecasting models are designed using Seasonal Autoregressive Integrated Moving Average and Facebook’s Prophet Library through optimal hyperparameters for better prediction. An AQI category classification model is also presented using classical machine learning techniques. The experimental results confirm the substantial improvement in air quality and greater reduction in PM2.5 due to the lockdown imposed during the COVID-19 crisis.     

Ovarian Dysfunction Induced by Chronic Whole‐Body PM2.5 Exposure

Fine particulate matter (PM2.5) pollution arouses public health concerns over the world. Increasing epidemiologic evidence suggests that exposure to ambient airborne PM2.5 increases the risk of female infertility. However, relatively few studies have systematically explored the harmful effect of chronic PM2.5 exposure on ovarian function and the underlying mechanisms. In this study, female C57BL/6J mice are exposed to filtered air or urban airborne PM2.5 for 4 months through a whole‐body exposure system. It is found that PM2.5 exposure significantly caused the alteration of estrus cycles, reproductivity, hormone levels, and ovarian reserve. The granulosa cell apoptosis via the mitochondria dependent pathway contributes to the follicle atresia. With RNA‐sequencing technique, the differentially expressed genes induced by PM2.5 exposure are mainly enriched in ovarian steroidogenesis, reactive oxygen species and oxidative phosphorylation pathways. Furthermore, it is found that increased PM2.5 profoundly exacerbated ovarian oxidative stress and inflammation in mice through the NF‐κB/IL‐6 signaling pathway. Notably, dietary polydatin (PD) supplement has protective effect in mice against PM2.5‐induced ovarian dysfunction.These striking findings demonstrate that PM2.5 and/or air pollution is a critical factor for ovarian dysfunction through mitochondria‐dependent and NF‐κB/IL‐6‐mediated pathway, and PD may serve as a pharmaceutic candidate for air pollution‐associated ovarian dysfunction.     

进气流量对PM2.5切割器捕集效率的影响

市面上常见的切割器均规定了固定的工作流量,当进入切割器的气流量不符合其标准工作流量时,就会带来捕集效率的偏差。通过搭建基于静态箱法的切割器捕集效率评价系统,对国产、进口的旋风式PM2.5切割器的捕集效率进行了评价,研究了切割器标准工作流量及该值的70%、80%、120%、130%作为抽气流量时对PM2.5切割器的捕集效率的影响。实验结果表明,PM2.5切割器的Da50会随着进气流量的改变呈现相反的变化趋势,Da50值分布范围为标准工作流量下该值的140%至80%;但捕集效率曲线的几何标准偏差在不同进气流量下几乎不变,对比标准工作流量下的偏移量不超过0.9%。该研究结果对于进一步规范切割器的制造及使用提供参考。