乌鲁木齐市PM2.5质量浓度增速的动态分析

采用基于长期约束下的结构向量自回归(SVAR)方法,以SO_2排放来刻画乌鲁木齐PM2.5质量浓度增长.GDP冲击、城市化人口水平冲击表现为近似反向的现象,使得SO_2冲击总是比GDP、城市化人口冲击滞后一期,大约在第10期对SO_2排放增速的影响为0.在讨论PM2.5质量浓度增速的影响因素中,归因于经济增长的比重约为11.2%.通过回归模型得到,经济增速对PM2.5质量浓度增速的边际效应为2.280,人口增长对PM2.5质量浓度增速的边际效应为12.293.最后,通过稳定性检验得到模型相关参数的稳定性.     

2016-2020年春节烟花爆竹燃放对绵阳市环境空气质量的影响

利用2016-2020年绵阳市环境空气(SO2,NO2,CO,O3,PM2.5和PM10)监测数据,分析了春节期间烟花爆竹燃放对绵阳市城区环境空气质量的影响.结果表明:烟花爆竹燃放对环境空气质量产生严重影响,除夕烟花爆竹燃放后,SO2和颗粒物(PM2.5和PM10)均会升高,PM2.5增长尤为明显,正月初一达到峰值浓度...     

PM2.5的时间分布与演变扩散研究

最初利用时间序列——指数平滑法来分析PM2.5的时间分布情况.考虑到在分析过程中不确定PM2.5与时间之间存在怎样的关系,所以分别建立了一次、二次及三次指数平滑模型,通过对比分析最终确定PM2.5与时间的具体关系.为了更好的控制和治理PM2.5污染物,则需要对其扩散规律进行分析,基于此,本文建立了基于高斯扩散模型的PM2.5污染物扩散模型,建模过程中,首先建立了大气稳定状态下的基本模型,然后在此基础上又进一步建立了能够反映风速、温度以及湿度对PM2.5扩散产生影响的基本模型,具有一定的适用性.     

中国2001-2013年PM2.5重污染的历史变化与健康影响的经济损失评估

回顾21世纪以来中国PM2.5重污染及其健康影响与损失的历史变化,通过构建2001—2013年中国31个省PM2.5重污染数据集,结合最新的流行病学剂量–反应关系研究结果,同时在死亡风险赋值中考虑年龄结构的影响,评估2001年以来各省因PM2.5重污染对人群健康的影响与相应的经济损失。研究结果表明,2001年以来PM2.5重污染现象持续发生,全国平均每年71%的省份都受到重污染的影响。尽管13年间的PM2.5重污染浓度并未呈现明显恶化趋势,且发生比例及其健康影响在2001—2012年间持续减少,但2013年出现长时间的重污染现象,成为13年间重污染发生比例/频率最高的年份。2013年因PM2.5重污染带来的过早死亡达6.5万例,健康损失为281亿元,相当于2001—2013年期间健康损失总和的54%。其中,中东部8个省份和2013年1月的持续重污染是2013年健康损失显著增加的主要原因。     

昆明市PM_(2.5)浓度时空变化特征及其与气象条件的关系

针对高原山地城市PM2.5的污染及防治问题,利用2014年4月—2015年3月昆明市主城区PM2.5小时浓度平均值及对应的气象参数连续观测资料,采用普通克里格插值法、非参数分析法对昆明市主城区PM2.5浓度时空特征及其与气象因素的影响进行了研究分析.研究结果表明:昆明市主城区PM2.5浓度季节高低为春季冬季秋季夏季.PM2.5日变化趋势呈双峰单谷型,上午PM2.5浓度高于下午浓度,这种变化趋势与人们出行高峰和当天气象条件有关.普通克里格插值法得到昆明市PM2.5高浓度主要分布在主城区西北至东南一带,五华区、盘龙区浓度高于西山区、呈贡区.通过Spearman秩相关分析得出日均温度、气压、风速气象因子对环境PM2.5浓度的季节分布具有显著影响.     

重庆中心城区空气污染特征及气象影响因素分析

根据环境空气质量监测数据和气象观测数据,对重庆中心城区2013—2020年空气污染特征及气象影响因素进行了分析.结果表明:2013—2020年影响重庆中心城区空气质量的大气污染物主要为PM2.5和O3,重度污染日首要污染物基本为PM2.5;PM2.5污染和O3污染均呈现出明显的季节差异,PM2.5超标主要出现在初春、秋...     

长沙市PM2.5浓度时空分布特征及影响因子分析

为分析长沙市PM2.5浓度时间变化特征、空间分布特征及其影响因子,利用数据统计分析、克里金空间插值技术、地理探测器等方法与Arc GIS平台表达,选取长沙市中心城区10个监测点2013—2019年PM2.5日变化数据.结果显示:在PM2.5浓度时间变化特征方面,不同季节中,PM2.5浓度表现出冬季>秋季>春季>夏季的季节特征,不同时段中,各季节PM2.5浓度日均小时变化曲线均大致呈双峰形态;在PM2.5浓度空间变化特征方面,PM2.5浓度的高值区主要分布在中部芙蓉区,整体呈城区向郊区逐渐递减的变化规律.根据地理探测器研究结果发现,2017年长沙主城区PM2.5浓度主要受气温、降雨和风速因子影响,其次是道路、相对湿度、气压和人口密度,高程、植被和餐饮因子影响较小;且任意两个影响因子共同作用均会对PM2.5浓度影响增强.     

大气颗粒物PM2.5及其危害

PM2.5代表空气动力学等效直径等于和小于2.5微米的大气颗粒物。PM2.5是造成雾霾天气、降低能见度,影响交通安全的主要因素。PM2.5通过呼吸道进入肺泡,危害人体健康。PM2.5的基本特征是体积小、重量轻,在大气中滞留时间长,可以被大气环流输送到很远的地方,造成大范围的空气污染。PM2.5对环境的影响范围和对人体健康的危害程度,比PM10和PM100更大、更严重。美国、日本、欧盟等发达国家早已把PM2.5列为国家标准污染物。2012年我国政府已经颁布PM2.5国家标准(0.035毫克/立方米.年和0.075毫克/立方米.日),将于2016年开始在全国范围内进行常规监测,并向公众报告监测数据。     

基于多层组合模型的武汉市月平均PM2.5浓度预测

构建一款组合预测模型,精准预测武汉市PM2.5浓度,探讨其对地区空气质量产生的影响.研究结果显示,武汉市2020年1-4月份月平均PM2.5浓度实际值远小于预测值,差距最大的2月份,实际月平均PM2.5浓度比预测的正常值低30.37μg/m3,仅为预测值的55.63%.2020年5月份后,月平均PM2.5浓度预测值与实际值之间差距不明显.说明新冠疫情期间各地居民减少了户外活动,空气质量有明显改善.     

河南省供暖期大气污染特征及预测分析——以郑州市为例

近年来河南省大气污染问题引起社会的广泛关注,但有关供暖期间大气污染方面的研究相对较少.以郑州市为例,分析郑州市供暖期间大气颗粒物的浓度变化并进行预测,对提高当地空气质量具有重要意义.基于2014-2016年郑州市空气质量监测数据和同期气象数据,利用SPSS相关分析和BP神经网络模型,分析郑州市供暖期间PM2.5、PM10的超标情况、日变化特征,探究气象要素对PM2.5和PM10的影响,最后预测AQI指数的变化.结果表明:2014年供暖期郑州市空气质量相对较差,PM2.5和PM10平均质量浓度超标率最高;2015年供暖期郑州市空气质量相对较好,PM2.5和PM10平均浓度变化幅度较大;2014-2016年供暖期间郑州市PM2.5和PM10浓度具有明显的日变化特征,呈现双峰型变化;2014-2016年供暖期郑州市PM2.5、PM10与日均气温相关性不显著,与日均风速呈显著负相关,与日均相对湿度呈显著正相关;当供暖期郑州市主导风向为正西风时,污染天气出现频率较低;利用BP神经网络预测2016年AQI的精度较高,预测值与实测值相关系数为0.85.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with