Charge transport in conducting polyaniline co-doped with sulfosalicylic acid and dodecylbenzoyl sulfonic acid     

MA Li  YAN Jun  GAN Meng-Yu  HE Ling  LI Jian-Feng 《重庆大学学报(英文版)》2009,8(3):170-174

We prepared conducting polyaniline （PAn） co-doped with sulfosalicylic acid （SSA） and dodecylbenzoyl sultonic acid （DBSA） in micro-emulsive polymerization, and studied its charge transport behaviors based on the measurement of its electrical conductivity in the temperature range between 203 K and 298 K. The conductivity was found to increase with temperature, similar to the case in semiconductors. Analyzing the experimental data with three models, namely the charge-energy-limitedtunneling model, Kivelson model and the three-dimensional variable range hopping （3D-VRH） model demonstrated that these models all describe well the charge transport behaviors of PAn co-doped with SSA and DBSA within the mentioned temperature range. From calculation with the 3D-VRH model, the hopping distance of the conducting PAn is obviously larger than its localization length. The PAn doped with SSA and DBSA enjoys desirable crystallinity due to the co-doping of two functional sulfonic acids. The macroscopic conductivity may correspond to three-dimensional transport in the network of the bundles, and the metallic islands may be attributed to quasi-one-dimensional bundles.  相似文献   

浅谈铁路建设对怀化经济发展的影响     

彭旺 《怀化学院学报》2009,28(7):31-32

在经济全球化深入发展、区域竞争日趋激烈的今天,作为经济发展硬环境构成要件的交通基础设施,已成为影响一个地区经济发展的重要因素。怀化被誉为"火车拖来的城市"。交通尤其是铁路在城市的形成和发展过程中发挥过不可替代的作用。在"十一五"新一轮发展中,作为内陆山区的怀化,仍需坚持交通先行,把交通建设摆到重要位置全力加以推进。  相似文献   

对一种新型探测器蒙特卡罗方法模拟验证     

张军民  周剑良  凌球  屈国普  王喜宗 《衡阳师范学院学报》2009,30(3):41-43

介绍了用蒙特卡罗方法模拟光子在一种新型用于总β测量的闪烁探测器中的输运过程,结果表明探测器能使γ本底降低一个数量级左右.  相似文献   

Cyclic electron flow around photosystem I is required for adaptation to high temperature in a subtropical forest tree, Ficus concinna   总被引：1，自引：0，他引：1  

Song-heng Jin  Xue-qin Li  Jun-yan Hu  Jun-gang Wang 《Journal of Zhejiang University. Science. B》2009,10(10):784-790

Dissipation mechanisms of excess photon energy under high-temperature stress were studied in a subtropical forest tree seedling, Ficus concinna. Net CO2 assimilation rate decreased to 16% of the control after 20 of high-temperature stress, and thus the absorption of photon energy exceeded the energy required for CO2 assimilation. The efficiency of excitation energy capture by open photosystem Ⅱ (PSII) reaction centres (Fv'/Fm') at moderate irradiauce, photochemical quenching (qp), and the quantum yield of PSII electron transport (φPSII) were significantly lower after high-temperature stress. Nevertheless, non-photochemical quenching (qHP) and energy-dependent quenching (qE) were significantly higher under such conditions. The post-irradiation transient of chlorophyll (Chl) fluorescence significantly increased after the turnoff of the actinic light (AL), and this increase was considerably higher in the 39 ℃-grown seedlings than in the 30 ℃-grown ones. The increased post-irradiation fluorescence points to enhanced cyclic electron transport around PSI under high growth temperature conditions, thus helping to dissipate excess photon energy non-radiatively.  相似文献   

日本数值预报模式热带气旋预报误差分析     

杨亚新 《上海海事大学学报》2012,33(3):5-9

为了给海上航行船舶防避热带气旋(Tropical Cyclone,TC)提供参考,利用2010和2011年日本TC警报图上提供的36个TC实时、综合预报资料,采用数理统计方法分析TC路径和强度预报误差.结果表明:24,48,72 h TC预报路径的平均距离误差分别为106.5,194.8,306.4 km;随着预报时效的增加,距离误差分布范围增大;路径预报主要偏向SW和NE象限,其次为SE和NW象限;TC强度预报误差随预报时效的增加而增大;24,48,72 h最大风速预报的平均绝对误差分别为7.4,11.7,13.6 kn,中心气压的平均绝对误差分别为0.80,1.27,1.46 kPa;一般情况下,预报强度偏强的频率较大,预报强度偏弱的频率较小,且强度预报偏弱时,预报误差的幅度往往较大;路径预报的平均距离误差随强度增强而减小,而平均强度误差(即中心气压和近中心最大风速预报误差)随强度增强总体呈增大的趋势.  相似文献   

Skiing accidents in the past 15 years     

P. Matter  W. J. Ziegler  P. Holzach 《Journal of sports sciences》2013,31(3):319-326

For the last 15 years a statistical analysis of distances skied and of alpine skiing accidents has been performed in the Davos‐Klosters skiing area, a ‘closed’ skiing area, where every skier has to return from the top to the bottom station. Distance skied is measured by vertical drop in 10⁶ km determined by calculations from frequency surveys by lift‐operators. About 2.5 million km per season have been skied during the past years, a number remaining constant for the last 15 years. In the same time the requirement for rescue‐transports in this area has shown a decline of 46% to 288 transports per season due to a decrease of the number of injuries with initial immobilization. Therefore the so‐called transport‐quotient (one rescue‐transport per 10⁴ km of vertical drop skied) has decreased from its initial value of 4 to 1 per 10⁴ km. During the same time all winter sport injuries were analysed at the hospital of Davos. About 90% are injuries caused by alpine skiing resulting in a total of 17 246 alpine skiing injuries for the last 15 years. There is a great decline in the incidence of lower leg fractures with a contrary development of knee injuries. Today half of the lower leg injuries are knee injuries (280 knee injuries out of a total of 1250 alpine skiing accidents per season). There is a gradual increase of upper extremity injuries from 17% of all skiing injuries in 1972 to 35% in 1976. A Swiss multicentre study on skiing safety shows comparable injury patterns in other skiing areas. The average injury‐severity measured by several parameters is declining.

In a technical investigation of skiing equipment of 1072 persons who sustained an accident, only 32% had ski bindings with tolerable frontal release and 17% with tolerable torsional release. Parallel measurements of bindings of 600 non‐injured skiers gave the same alarming results. More research on the correlation between binding adjustment and knee injuries is needed.  相似文献   

城市客运交通本科教学改革初探     

薛运强  张兵  安静 《教育教学论坛》2019,(21):96-97

城市客运交通是交通工程专业核心课程之一,主要研究城市客运交通系统规划设计、运营管理、公交专用道设置等内容。作为交通特色的高校青年教师,结合"公交都市"创建和华盛顿协议要求,对该课程教学改革进行了一些探索。  相似文献   

秦汉蜀晋南朝的治边方略与云南通道开发   总被引：1，自引：0，他引：1  

方铁 《云南师范大学学报(哲学社会科学版)》2007,39(6):49-54

秦至南朝的800余年,是云南早期历史发展的关键时期。这一时期云南地区的主要通道先后开通,并经历了兴衰变化的过程。秦汉蜀晋南朝诸朝的治边方略,对云南通道的开发产生重要影响。本文收集相关的零散资料,阐述秦汉蜀晋南朝时期云南通道开发的情形,并分析秦汉蜀晋南朝的治边方略与云南通道开发的关系。  相似文献   

现代通信实训平台建设与实验教学改革   总被引：3，自引：0，他引：3  

邓月明  王玲  周志彬 《实验室研究与探索》2007,26(12):122-125

针对现代通信实验发展的新趋势,构建了一套包括程控交换、光传输和网络通信在内的现代通信实训平台,并完成了相应的实验教学内容、实验教学方式等改革,很好的完善了整个实验教学体制和实验教学内容,为学生在电信系统及工程应用方面提供了完善的实践平台。  相似文献   

高职学生课外活动取向的调查     

邵爱杰  付昌辉 《黄冈职业技术学院学报》2004,6(4):94-96

高职学生拥有较多的课外时间。合理、有效地利用课外活动时间,对发展高职教育有着重要 的意义。它既能促进学习和增强技能,又能开拓视野和丰富生活,从而提高了学生的综合素质能力。笔者 针对这一情况,展开了一定调查和分析,发现当前的高职学生利用课外时间进行学习的情况不容乐观。  相似文献