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1.
《北京工业职业技术学院学报》2010,(1)
利用质粒DNA损伤评价方法研究了北京市天坛地区2007年可吸入颗粒物(PM10)的毒理学特征,同时利用高分辨率场发射扫描电镜(FESEM)和图像分析技术(IA)研究了区内可吸入颗粒物的微观形貌类型及百分含量特征。结果表明,天坛地区PM10生物活性具有明显季节性差变化,从高到低依此为:冬季夏季秋季春季。在天坛地区大气PM10中识别出烟尘集合体、燃煤飞灰、矿物和超细未知颗粒等4种单颗粒类型,其中烟尘集合体与颗粒物毒性呈正相关关系,冬季PM10的较高的生物活性与较高的烟尘集合体的数量百分比有紧密关系。 相似文献
2.
分析了北京市石景山区秋季PM10质量浓度的变化特征,发现气候变化对PM10质量浓度有很大影响。利用带能谱的扫描电镜（SEM／EDX）分析了PM10的微观形貌特征,区分出矿物颗粒、燃煤飞灰、烟尘集合体、超细颗粒物和未知颗粒物等五种成分,并对所采样品中的矿物颗粒成分进行了分析。石景山区PM10污染呈燃煤污染、机动车尾气污染和扬尘污染的复合污染特征。 相似文献
3.
本文主要利用高分辨率场发射扫描电镜(FESEM)对北京市大气可吸入颗粒物样品进行微区形貌和成分分析,区分出三种不同形态的烟尘集合体:链状、蓬松丛状和密实块状。链状烟尘和蓬松团块状烟尘既可能来自机动车尾气,也可能来自燃煤,而密实块状烟尘可能来自煤的燃烧。通过X射线能谱(EDX)分析,北京大气PM10中主要矿物类型包括硅铝酸盐、石英、石膏、白云石以及部分由两种矿物组成的沙尘等。 相似文献
4.
利用TE-20-800型8级分级采样器采集焦作市燃煤电厂区、文教生活区、商业区和交通区大气颗粒物,通过重量法求出不同粒径颗粒物的质量浓度,研究可吸入颗粒物粒径分布特征和质量浓度分布特征发现：焦作市各功能区中可吸入颗粒物粒径分布呈现＂两边凸中间凹＂的趋势,峰值位置出现在5.8μm~10.0μm和2.1~0.43μm处;研究区空气中PM10浓度均高于国家空气质量二级标准（PM10浓度的日平均值为0.15 mg/m3）,与我国新制定的PM2.5日均浓度限值相比（0.075mg/m3）,文教生活区、交通区、商业区PM2.5浓度分别为其2.22、1.02、1.66倍,燃煤电厂区低于此标准。 相似文献
5.
利用TE-20-800型8级分级采样器采集焦作市燃煤电厂区、文教生活区、商业区和交通区大气颗粒物,通过重量法求出不同粒径颗粒物的质量浓度,研究可吸入颗粒物粒径分布特征和质量浓度分布特征发现:焦作市各功能区中可吸入颗粒物粒径分布呈现"两边凸中间凹"的趋势,峰值位置出现在5.8μm~10.0μm和2.1~0.43μm处;研究区空气中PM10浓度均高于国家空气质量二级标准(PM10浓度的日平均值为0.15 mg/m3),与我国新制定的PM2.5日均浓度限值相比(0.075mg/m3),文教生活区、交通区、商业区PM2.5浓度分别为其2.22、1.02、1.66倍,燃煤电厂区低于此标准。 相似文献
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7.
用PM3法计算了O,O一二甲基—a—（N—甲氨基甲酰氧基）三氯甲基膦酸酯的电子结构,讨论了分子的电子结构与生物活性的关系。 相似文献
8.
石家庄市区大气污染物浓度变化特征研究 总被引：1，自引：0，他引：1
《石家庄学院学报》2015,(6):81-87
利用2014-2015年3月SO2,NO2,PM10,PM2.5,CO和臭氧的观测数据,分析了石家庄市主要大气污染物的变化特征.结果表明,臭氧夏季平均浓度值最高;NO2夏季浓度值最低;PM2.5,SO2和CO冬季浓度最高,夏季浓度最低;而PM10浓度春季最高,较为明显的高于其它3个季节.臭氧四季的日变化均呈单峰型,其余五项污染物浓度四季的日变化呈现出"早峰午谷",且夜间出现小高峰.掌握石家庄市大气污染物的变化特征,可为大气环境治理工作与防控措施研究提供科学依据. 相似文献
9.
本文初步统计了扬州市2013年1-3月份PM2.5指数,冬季偏高,有明显的季节特征,分析了扬州地区2011-2012年人体不适度指数与呼吸科、消化科、神经内科及肿瘤科就诊人数的关系,反映了扬州人体健康特征对气候变化的响应. 相似文献
10.
利用定义解圆锥曲线问题是解决解析几何问题的重要思路,通过多年的教学研究,笔者归纳出一些规律,并在教学实践中加以应用,取得了良好的效果,下面笔者分5种类型加以阐述.1要善于利用定义确定轨迹和轨迹方程,同时注意定义的条件例1已知双曲线x2a2-y2b2=1（a〉0,b〉0）,P在右支上,F1、F2为焦点,∠F1PF2的角平分线为PM,F1M⊥PM于点M,求M的轨迹方程. 相似文献
11.
Tower of Hanoi has become a popular tool in cognitive and neuropsychology to assess a set of behaviors collectively referred to as executive functions. Substantial variability in performance on the Tower of Hanoi (TOH) disk-transfer task among normally functioning young adults, and potential contributions to these individual differences, were examined. In this expanded 60-problem version of the four-disk TOH, the degree to which problem administration (blocked vs. random) and strategy knowledge influenced overall performance and changes in accuracy across problems was examined. Eighty-seven college students were randomly assigned to a Blocked Group (problems given in ascending order of move-length) and a Random Group (problems given in a random order). After administration of the TOH task, participants described their problem solving and these verbal protocols were analyzed with regard to four elements of a strategic approach to problem solving. Problem administration order demonstrated no effect on task performance or on expressed strategy knowledge; however, strategy knowledge did predict performance on the TOH. An expected decrease in performance across trials was observed in the Blocked Group, and an increase in accuracy in the Random group indicated a learning effect. Strategy knowledge did not interact with these changes in performance across the items. These results suggest that external cues do not influence performance on the TOH to the same extent as individual differences in strategy induction relatively early in the problem solving process. 相似文献
12.
黄宇婷 《北京工业职业技术学院学报》2008,7(1):12-14,89
作为传统的重工业区,石景山区的工业污染较严重,对北京市的空气质量有着重要影响。以2006年北京市环保局空气质量日报为依据,分析对比了北京市区与石景山区受可吸入颗粒物影响天数和可吸入颗粒物浓度变化情况。北京要实现可吸入颗粒物污染的治理目标,应将石景山区可吸入颗粒物的污染列为控制重点。 相似文献
13.
WANG Fang CHENG Shui-yuan LI Ming-jun FAN Qing CHEN Dong-sheng WANG Hai-yan ZHANG Wei 《重庆大学学报(英文版)》2010,9(3):117-123
We developed and tested an improved neural network to predict the average concentration of PM10 （particulate matter with diameter smaller than 10 μm） several hours in advance in summer in Beijing. A genetic algorithm optimization procedure for optimizing initial weights and thresholds of the neural network was also evaluated. This research was based upon the PM10 data from seven monitoring sites in Beijing urban region and meteorological observation data, which were recorded every 3 h during summer of 2002. Two neural network models were developed. Model I was built for predicting PM10 concentrations 3 h in advance while Model II for one day in advance. The predictions of both models were found to be consistent with observations. Percent errors in forecasting the numerical value were about 20%. This brings us to the conclusion that short-term fluctuations of PM10 concentrations in Beijing urban region in summer are to a large extent driven by meteorological conditions. Moreover, the predicted results of Model II were compared with the ones provided by the Models-3 Community Multiscale Air Quality （CMAQ） modeling system. The mean relative errors of both models were 0.21 and 0.26, respectively. The performance of the neural network model was similar to numerical models, when applied to short-time prediction of PM10 concentration. 相似文献
14.
阐述了环境空气中颗粒物的粒径分布状况,以实际监测结果分析了漯河市环境空气中TSP和PM10的浓度相关性.统计检验表明,漯河市TSP和PM10显著性相关. 相似文献
15.
遂宁市大气主要污染物污染水平及变化规律 总被引：2，自引：0，他引：2
根据遂宁市2006年1月1日至2010年12月31日的环境监测数据,采用API指数法分析和评价了遂宁市大气中污染物变化规律.结果表明：各功能区的PM10的日平均浓度为0.077－0.123 mg/m^3,二氧化硫为0.030－0.043 mg/m^3,二氧化氮为0.022－0.025 mg/m^3,空气污染指数小于100.在时间变化规律上,各功能区PM10污染总体表现为第一季度污染相对稍重,其次为第二季度,再次为第四季度,第三季度污染较轻.在空间变化规律性上,以城南（群康印染厂）工业区污染稍重,次之为城西（监测站）片区,河东新区（市行政中心）环境质量最好.提示遂宁市可吸入颗粒物为空气中的主要污染物. 相似文献
16.
王斯文 《金华职业技术学院学报》2014,(2):60-65
随着中国空气质量的不断恶化,PM2.5污染逐渐成为大众关注的话题之一,而居民的环保意识是影响PM2.5数值的一个重要因素。为了更好地减少和防治PM2.5污染,深入了解居民环保意识对PM2.5污染的影响,对金华市居民环保意识和PM2.5污染现状进行了调研,并利用SPSS20.0软件对两者数值变化进行了相关性分析。结果表明,2013年金华市居民环保意识相比2012年明显提高,PM2.5数值相比2012年有所下降,提升居民环保意识对PM2.5污染有显著的负相关性。针对金华市具体情况提出继续倡导节能减排、绿色低碳,积极推进健康环保新理念,深入农村开展环保宣传等对策,为进一步提高居民环保意识、降低PM2.5提供理论依据。 相似文献
17.
三台县城区大气环境质量分析与评价 总被引：1，自引：0，他引：1
根据2006～2007年三台县城区SO2、NO2、PM10浓度的监测数据,综合运用大气环境质量指数评价法和污染负荷分析法对三台县城区的大气质量进行分析与评价。结果表明：三台县城区主要大气污染物依次为PM10、SO2和NO2,污染程度相对较低,2007年较之2006年大气质量总体上有较大改善。SO2和PM10在2006～2007年间污染负荷均呈下降趋势,而NO2则呈现上升趋势,说明三台县城区大气污染正由煤烟型逐步向燃气型的趋势过渡。 相似文献
18.
The transition from school to university can prove problematic for a number of academic and social reasons and first-year attrition rates are high. Research suggests that first-year students need help adjusting to a new phase of learning in a larger community of practice and that a student’s decision to leave represents a negative combination of multiple integration variables. One practice that may help to reduce stress and subsequently assist in lowering first-year attrition rates is a peer pentoring (PM) scheme. Within the Centre for Biomedical Sciences Education (CBMSE) at Queen’s University Belfast (QUB) a PM scheme was designed to engage new students in informal supportive relationships with more experienced students. Qualitative reports indicate that the scheme provided an avenue for new students to reappraise their previous expectations of university and develop a sense of identity within their course. An added benefit from this PM scheme was that it also allowed older students to gain transferrable employment-related skills in communication, teamwork and organisational expertise. In 2009–10, 9.1% of Biomedical Science (BMS) students, studying at QUB, did not return to the second year of their degree; however, following implementation of a PM scheme in 2011–12, figures show a reduction of first-year attrition to 3%. While such improvement is characteristic of many transition initiatives, not just those associated with PM, it is likely that implementation of PM is intrinsically linked to student retention within a course. 相似文献
19.
使用综合污染指数与API指数评价方法,对近五年乌鲁木齐市大气污染特征进行了分析．结果表明,环境空气中二氧化硫、可吸入颗粒物年均浓度均超过国家二级标准,二氧化氮年均浓度尚能达标,但总体呈上升趋势;乌鲁木齐首要污染物为可吸入颗粒物,其次为二氧化硫;采暖期环境空气污染严重,非采暖期空气质量良好． 相似文献
20.
Diane Santa Maria Christine Markham Paul Swank Elizabeth Baumler Sheryl McCurdy Susan Tortolero 《Sex education》2014,14(3):286-298
This study examined parental monitoring (PM) as a potential moderator of the relation between parent–child communication (PCC) and pre-coital sexual behaviours (PCSB) in an urban, minority, early adolescent population. Seventh-grade students (n = 1609) reported PCC, PM and PCSB. Multivariable logistic regression was conducted to assess for moderation. PM moderated the association between PCC and PCSB. Specifically, young people reporting both high PCC and high PM had the lowest odds of PCSB. Findings suggest that PCC is more protective in combination with high PM. However, young people reporting low levels of PM had an increased probability of PCSB with higher levels of PCC. No moderating effect between PCC, PM and PCSB was found by race/ethnicity or gender. However, race/ethnicity was found to moderate the effect of PCC on PCSB. This knowledge highlights the protective role of parental factors on PCSB and may inform the development of more effective parent-based adolescent sexual health interventions that address both PCC and PM. 相似文献