太原地区冬春季PM2.5污染特征及影响因素     

孟昭阳张怀德  蒋晓明颜鹏 王雁林伟立  周春红刘洪利闫世明  梁丽明 《中国科学院大学学报》2007,24(5):648-656

采用美国R&P公司生产的TEOM系列1400A大气粒子（PM2.5）监测仪于2005年12月17日至2006年3月28日对太原地区PM2.5质量浓度进行在线观测。对观测期间2417个PM2.5小时平均浓度观测数据进行分析,得到小时平均浓度的平均值是247.6µg/m3(193.7 µg/m3)。在50-100µg/m3之间的PM2.5浓度出现的频率最高,PM2.5小时平均浓度小于400 µg/m3的频率为84.1%。PM2.5浓度日变化为双峰双谷型。太原市区PM2.5浓度与风速、能见度和气压呈负相关,与相对湿度呈正相关。通过3d 后向轨迹分析了影响太原地区气团的主要传输路径,结果表明,100 m高度上空的后向轨迹可划分为7种基本类型,其中第3类轨迹对应的PM2.5浓度值为342.6 µg/m3,明显高于其它类型。这类轨迹主要是来自太原的西南方向;而来自东边方向的第1类轨迹对应的PM2.5浓度为261.1 µg/m3,也比来自西北方向的2、4类轨迹PM2.5浓度高。观测结果表明在沙尘暴影响严重的日期,太原地区PM2.5浓度会极大地增加,从而对大气环境形成严重的污染。  相似文献   

现代性与大众文化的兴起   总被引：7，自引：0，他引：7  

孙爱军 《淮阴师范学院学报(哲学社会科学版)》2000,(5)

现代化进程中形成的现代性和现代感觉 ,影响着文化的内容和形式。从表层看 ,大众文化是以商品性、技术性、大众性面貌出现的文化 ;从深层看 ,是大众对日常生活的现代感觉。在本土化的语境中 ,大众文化有积极的意义 ,但又需要具体情况具体分析  相似文献   

Axisymmetric solutions of the Chaplygin gas for initial negative radial velocity     

郭俐辉  盛万成 《上海大学学报(英文版)》2010,14(5):380-386

In this paper, a three-parameter family of self-similar and weak solutions are constructed rigorously in two space dimensions for all positive time to the Euler equations with axisymmetric and radial negative initial velocity for the Chaplygin gas. Under the axisymmetry and self-similar assumptions, the equations are reduced to a system of three ordinary differential equations, from which we obtain structures of solutions besides their existence. The solutions exhibit some phenomena, such as formation and evolution of black hole, expansion and explosive expansion, in the evolution of universe.  相似文献   

Be My Guest: A Survey of Mass Communication Students' Perception of Guest Speakers     

Patrick F. Merle  Clay Craig 《College Teaching》2017,65(2):41-49

The use of guest speakers as a pedagogical technique across disciplines at the college level is hardly novel. However, empirical assessment of journalism and mass communication students' perceptions of this practice has not previously been conducted. To fill this gap, this article presents results from an online survey specifically administered to such students (N = 545) at a large public research university and a small liberal arts college. Results of statistical significance indicate that inviting a guest speaker is most valuable to students when the speaker comes from the industry and interacts face-to-face with the audience through personal examples and career tips rather than a formal slide-based lecture. Finally, this article contributes to and expands upon previous literature by offering a set of recommendations for the use of guest speakers in journalism and mass communication curriculum.  相似文献   

Cross-sectional comparison of body composition and resting metabolic rate in Premier League academy soccer players: Implications for growth and maturation     

Marcus P. Hannon  Daniel J. Carney  Stephen Floyd  Lloyd J. F. Parker  John McKeown  Barry Drust 《Journal of sports sciences》2020,38(11-12):1326-1334

ABSTRACT

For the first time we aimed to: (1) assess fat-free mass (FFM) and RMR in youth soccer players, (2) compare measured RMR to estimated RMR using previously published prediction equations, and (3) develop a novel population-specific prediction equation. In a cross-sectional design, 99 males from a Premier League academy underwent assessments of body composition (DXA) and RMR (indirect-calorimetry). Measured RMR was compared to estimated values from five prediction equations. A novel RMR prediction equation was developed using stepwise multiple regression. FFM increased (P<0.05) between U12 (31.6±4.2 kg) and U16 (56.3±5.3 kg) after which no further increases occurred (P>0.05). RMR in the U12s (1655±195 kcal.day^?1), U13s (1720±205 kcal.day^?1) and U14s (1846±218kcal.day^?1) was significantly lower than the U15s (1957±128 kcal.day^?1), U16s (2042±155 kcal.day^?1), U18s (1875±180 kcal.day^?1) and U23s (1941±197 kcal.day^?1) squads (P>0.05). FFM was the single best predictor of RMR (r²=0.43; P<0.01) and was subsequently included in the novel prediction equation: RMR (kcal.day^?1) = 1315 + (11.1 x FFM in kg). Both FFM and RMR increase from 12-16 years old, thus highlighting the requirement to adjust daily energy intake to support growth and maturation. The novel prediction RMR equation developed may help to inform daily energy requirements.  相似文献   

不同训练模式下羽毛球运动员心率和血乳酸的变化     

盛怡  郭黎  蒋健 《武汉体育学院学报》2017,51(4):92-95

通过不同羽毛球训练模式和模拟实战时运动员血乳酸和心率分布，了解不同训练模式时的供能特点。方法：测定12名高水平羽毛球运动员在5种不同训练模式下和实战比赛中血乳酸浓度和心率，以了解不同训练模式时的供能特点，为训练实践提供参考依据。结果：（1）5种训练模式运动后即刻和运动后5分钟运动员血乳酸均显著高于模拟比赛后（P<0.05），运动员运动后10分钟血乳酸浓度在训练模式1、模式2和模式5中均显著高于模拟比赛（P<0.05），5种不同模式中模式5在运动后即刻、运动后5分钟和运动后10分钟血乳酸最高（p<0.05）；（2）心率分布中，训练模式1和训练模式2下90% HRmax以上分布显著高于（P<0.05）模拟比赛；80-90% HRmax分布训练模式1、训练模式3和训练模式5显著高于模拟比赛（P<0.05）。结论：5种训练模式在发展ATP-CP和糖酵解系统供能能力各有侧重，模拟比赛的强度接近比赛要求。  相似文献   

Association of physical fitness,body composition,cardiometabolic markers and adherence to the Mediterranean diet with bone mineral density in perimenopausal women. The FLAMENCO project     

Virginia A. Aparicio  Pilar Ruiz-Cabello  Milkana Borges-Cosic  Ana Andrade  Irene Coll-Risco  Pedro Acosta-Manzano 《Journal of sports sciences》2017,35(9):880-887

This study aimed to analyse the association of different components of physical fitness, body composition, cardiometabolic markers and the Mediterranean diet with bone mineral density (BMD) in perimenopausal women, and to test which of these components are independently associated with BMD. The sample comprised 197 perimenopausal women (52.6 ± 4.5 years). Physical fitness was assessed with the “Senior Fitness Test” battery and the handgrip strength and Bruce tests. Fat and lean mass and BMD were measured using dual-energy X-ray absorptiometry. We analysed the markers of metabolic syndrome, C-reactive protein, and components of the Mediterranean diet. Handgrip muscle strength (β = 0.212, P = 0.005), body weight (β = 0.244, P = 0.001), BMI (β = 0.180, P = 0.011) and lean mass (β = 0.379, P < 0.001) were positively associated with BMD. No associations were observed between cardiometabolic markers or the Mediterranean diet with BMD (all P > 0.05). When all relevant indicators of BMD were simultaneously considered, lean mass was the only 1 showing an independent association with BMD (β = 0.392, P < 0.001), explaining 14% of the BMD variability. In conclusion, muscle strength might be a marker of BMD in perimenopausal women. However, lean mass was the only factor independently associated with BMD. Future research to determine whether increasing lean mass through specific exercise-based interventions contributes to increasing BMD is warranted.  相似文献   

大众传媒视野中的奥林匹克文化传播--基于符号学的夏季奥运会口号文本分析     

刘媛媛  陈源 《南京体育学院学报(社会科学版)》2016,(2):33-37

在大众传媒蓬勃发展的背景下，以符号学作为研究的理论背景，运用文本分析的方法，对1984年到2012年间，共八届夏季奥运会的口号进行研究。从表层文字的拿捏到深层意涵的赋予，从看似简单的口号文本中梳理其所包含的奥林匹克文化的深厚底蕴。进行文本分析的过程分为以下两个层面：首先，从文字和语词的层面识别相关符号的表层含义；其次，从历史、社会、文化的层面探索相关符号的深层含义。研究认为：奥运口号是现代奥运会的重要标识，将历久弥新地被定义、被诠释、被命题；简短的奥运口号凝练了奥林匹克的精神，将作为一代又一代人们的集体回忆，将永载人类文明的史册并源远流长地传承下去。  相似文献   

广东省大众体育非均衡化现象分析及其对策研究     

杨晓生  陈长礼 《吉林体育学院学报》2015,(3):9-13

采用问卷调查法、对比分析法、文献资料法等研究方法对粤东、西、北与珠江三角洲大众体育现状进行比较分析,发现广东省大众体育区域发展不均衡,主要由经济水平差异、体育锻炼意识、大众体育与体育需求之间的矛盾所导致。对策：发展经济、平衡区域经济发展水平,因地制宜开展体育组织与协会,加强体育服务机构人员素质培养,合理开发利用场馆资源,积极宣传体育锻炼意识,鼓励开展大众体育活动。  相似文献   

用批判的态度分析大众传媒对不同受众意识形态的“塑造”     

李珍珠 《湖北函授大学学报》2015,(8):71-72

大众传媒的意识形态功能在很大程度上重新建构了主体的接收和认同方式,改变着人们的生产、生活和思维方式,生存体验,潜移默化地影响甚至塑造着人们的思想和观念,并在深层次上建构着人们的情感、幻想、价值观和思维方式以及对自我和世界的认知方式,形成了种种意识形态现象,加强对受众的科学意识形态的引导,迫在眉睫。  相似文献