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关键词： 人口密度   可持续发展   能源消费   家庭户   小型化   忽略   人口地理学   华东师大  

摘要： 中国人口地理学创始人胡焕庸教授（也是笔者1978—1982年在华东师大地理系学习时的恩师），于1935年提出的从黑龙江爱辉至云南腾冲的人口密度分界线（即胡焕庸线），直观形象地展示了当年我国东南地狭人稠、西北地广人稀的状况，

关键词： 桥梁损伤   影响线   健康监测系统  

摘要： 在过去几十年内，中国修建了许多大跨径桥梁，这些桥梁一经建成就开始了结构劣化的过程，且损伤在整个服役期间不断累积，该类损伤甚至可能造成桥梁坍塌事故。因此，不少新建的大跨桥梁上都安装了结构健康监测系统，用以监测桥梁健康状态。但截止至目前，将健康监测系统的实测数据运用于桥梁损伤识别，至少有以下三点关键问题尚未有效解决:(1)从监测系统的实测数据中提取出对损伤敏感而对环境变化不敏感的损伤指标;(2)利用监测系统多传感器信息增强损伤决策的可信度;(3)优化传感器布置方案以达到最好的损伤识别效果。\n 本篇论文旨在健康监测系统下基于影响线进行损伤识别，主要包括以下五个方面内容:(1)基于桥梁响应及荷载信息的影响线识别;(2)基于影响线构造损伤指标;(3)融合多传感器信息的损伤识别;(4)基于影响线量化损伤程度;(5)基于影响线损伤敏感性优化传感器位置。\n 论文首先提出一种新颖的基于移动车辆信息及对应响应时程的影响线识别方法，并在此基础之上，面向桥梁局部损伤识别，进一步构造出影响线损伤指标。为了解决基于单个传感器信息进行结构损伤识别，易受噪声干扰的不足，提出一种结合了D-S证据理论和影响线损伤指标的方法，该方法在融合了多个传感器信息后，可提供更为准确的损伤定位信息。为了验证一系列方法的有效性，采用香港青马大桥健康监测系统的实测应变响应数据及火车信息，识别桥梁多个关键构件的影响线。基于青马大桥的有限元模型，考虑了噪声干扰，验证了所提出的影响线损伤指标用于识别大跨桥梁局部损伤的损伤位置和相对损伤程度的可行性。同样基于该模型，还验证了考虑多传感器信息融合的损伤定位技术的有效性，比较了不同工况下信息融合的效果。\n 另外，论文还提出了一种基于挠度影响线的损伤程度量化方法，该方法基于单元刚度矩阵特征分解的技术，重构挠度影响线矩阵，最终可识别出单元损伤系数。该方法通过了数值模拟和实验室模型的验证，结果表明它可较准确地量化损伤的程度。另外，为了达到最佳的损伤识别效果，提出了一种结合Fisher信息阵和影响线损伤敏感性矩阵的传感器优化布置方法，该方法的有效性通过连续梁数值模型进行了验证。

关键词： 观测系统模拟试验   风廓线雷达   资料同化  

摘要： 针对一个南方切变线系统降水个例,通过观测系统模拟试验(OSSEs)对我国拟建风廓线雷达观测网内的不同类型风廓线雷达观测资料在GRAPES_MESO系统中的影响、对风廓线雷达观测和探空观测及两者混合使用时在GRAPES_MESO系统中的影响差异进行了初步分析和讨论。试验结果表明,在GRAPES_MESO系统中,风廓线雷达资料对500 hPa高度以下水平风速分析场的修正作用明显优于探空资料;风廓线雷达资料对水平风速分析场的影响高度极限大约在300 hPa附近,经过6h的传播,其影响可以向上继续传播至250 hPa以上高度;在300 hPa高度以下,同化对流层Ⅱ型风廓线雷达资料对水平风速分析场的影响比边界层型风廓线雷达资料略大;单独同化风廓线雷达资料对降水预报的贡献较弱,与探空观测混合使用时有助改进降水预报。

关键词： 超电晕   上行先导   抑制效果   雷电吸引能力   输电线路  

摘要： 在雷云电荷或雷电先导的感应作用下,表面缠绕了细线的导线或导体会产生超电晕,不仅能够抑制流注的形成,还能改变周围空间的电位分布,从而对周围导体的上行先导产生影响。因此超电晕近年来被认为在提高防雷性能方面具有良好的应用前景。然而相关研究表明,由于在输电线路防雷应用时超电晕由避雷线表面产生并发展,导致由避雷线表面起始并向上发展的上行先导也被抑制,因此输电线路整体的绕击防雷性能究竟是否提高还有待商榷。基于此,该文针对应用了超电晕的输电线路开展研究,通过建立超电晕与雷电先导同步发展的仿真模型,得到了应用超电晕后导线、避雷线的雷电吸引半径表达式,详细分析了超电晕对导线、避雷线引雷能力的影响,并与未应用超电晕时的引雷能力进行对比,研究结果表明尽管超电晕的应用同时削弱了导线、避雷线的引雷能力,但由于对导线引雷能力的削弱程度更高,使得应用超电晕后的屏蔽失效宽度大幅降低,从而输电线路整体的绕击防雷性能得到提高。最后通过500kV超高压输电线路的实例进行分析与验证。

关键词： Power transmission line   Re-freezing process of foundation soils   Foundation displacement   Thermosyphon   Permafrost  

摘要： The Qinghai-Tibet Power Transmission Line (QTPTL), crossing about 550 km permafrost regions, was constructed between July 2010 and October 2011. Based on 4 years of field observations since the construction, thermal and displacement performances of tower foundations in permafrost regions along the QTPTL were analyzed. The observational results from 10 monitored towers showed that the re-freezing process of foundation soils of deeply embedded pile foundations largely took 2 to 3 months. While for shallowly-buried footings, it took one to two cold seasons due to the significant thermal impacts of the foundation construction. After the re-freezing, the thermal regimes of foundation soils mainly determined by the thermosyphon cooling and enhanced heat transfer process of the concrete foundation. With the thermosyphon cooling, foundation soils around and under tower foundations cooled significantly and cold bulbs developed under tower foundations. But for shallowly-buried footings without thermosyphon, the maximum thaw near the footings could be as much as 2.0 m greater than that in the natural ground due to enhanced heat transfer process of the concrete footings. Foundation displacement observations at 130 monitored towers showed that the majority of tower foundations suffered subsidence rather than heave during the observational period. The subsidence was considerable in warm, ice-rich permafrost regions. After the tower assembling and line hanging, the subsidence rate of most of tower foundations decreased substantially. Up to the present, all 130 monitored tower foundations had the accumulative subsidence within an allowable range. Experiences and lessons learned from the QTPTL. will be of value for future similar constructions in permafrost regions. (C) 2015 Elsevier B.V. All rights reserved.

关键词： Co-occurrence   Eagle owl   Human impacts   Indicator species   Nestedness   Power lines   Ordination analysis  

摘要： The use of indicator species may save a considerable amount of resources when the attributes of other species or of the ecological process of interest are difficult or costly to measure directly. However, identifying indicator species is not easy and there is a need for rigorous criteria and methods for their selection. In this study, we test a new approach to select indicator species of high mortality-risk of electrocution in power pylons comparing methods based on biological criteria and network analysis. For this purpose, we studied 335 mortality records of 19 bird species electrocuted between 1996 and 2013 in a Special Protected Area located in South-eastern Spain. Our results showed that both species-biology based methods and network analyses provided similar results, indicating that the eagle owl can be considered the best mortality indicator of the bird community on power pylons for the study area. The use of network analysis to select indicator species can be very useful to optimize the monitoring of infrastructure impacts, especially on complex or understudied communities because it does not require detailed information on the biology of the species. (C) 2015 Elsevier Ltd. All rights reserved.

关键词： classroom   education   pedagogy   school architecture   teaching  

摘要： Viewed historically, for a thorough understanding of the development of pedagogical concepts it is necessary to study all important contextual elements that have contributed to the achievement of certain conditions under which educational work with students occurred, and to study all the qualitative components that lie at the essence of this pedagogical process. This paper examines the interdependence of pedagogical movements and classroom environment for the elementary education in the European historical context. The authors' analysis of historical trends in the development of pedagogical ideas and movements has identified two influential currents, in which implications related to the origins and final form of the highlighted school architecture in Europe have been analyzed. The key finding of this study is that, given the different socio-cultural circumstances, the level of development of the classroom in Europe is conditioned primarily by the continuity and quality of perception of pedagogical movements, as related to the appropriate environment in which the pedagogical process is to be implemented.

关键词： alpha-1 antitrypsin   apoptosis   autophagy   colon cancer cell line (HCT116)  

摘要： Alpha-1-antitrypsin (AAT), an acute phase protein, is the principal circulatory anti-protease. This multifunctional protein is encoded by the SERPINA1 gene. Although AAT was recognised as a potential tumour marker, its role in cancer biology remains unknown. Given that it has been demonstrated that AAT has an anti-apoptotic property against non-malignant cells, we aimed to investigate whether AAT affects apoptosis in a colon cancer cell line (HCT116). The presence of AAT in the HCT116 cell culture antagonized cytotoxicity of blockers of MEK1/2, PI3K/Akt pathways as well as NF-kappa B. The dominantly recovered cell viability was observed in the co-treatment with MEK1/2 inhibitor U0126. In addition, it was revealed that AAT almost completely abolished U0126-induced apoptosis through maintenance of the autophagy process. Our study revealed for the first time that the observed cyto-protection triggered by AAT was accompanied by sustained autophagy which opposed apoptosis. These results may contribute to understanding of the role of AAT in cancer development and evaluation of efficacy of cancer therapy.

关键词： Upward leader   Leader developing velocity   AC transmission line   Simulation experiment  

摘要： The problem of upward leader inception from transmission lines has not been thoroughly discussed, largely because of the difficulty to obtain experimental data under natural circumstances. Previous studies have primarily examined reduced-scale experiments or single-phase test lines. In this context, a real-size experimental system aimed at studying upward leader characteristics on both the phase conductor and ground wire is designed in this study. The results associated with real-size experiments corresponding to 110 kV, 220 kV, 500 kV and 1000 kV AC transmission lines, including the phase conductor and ground wire, are presented and discussed. It is shown that as the triggering voltage on the phase conductor increases, the streamer and leader incept earlier for a leader emerging from the phase conductor, and incept later for a leader emerging from the ground wire. The increase of the triggering phase angle corresponds to a higher voltage on the phase conductor, thereby increasing the strike probability on the phase conductor. The leader velocity and charge density present, in general, an increasing trend for the phase conductor as a function of the phase angle, while an opposite trend is observed for the leader emerging from the ground wire except for some special occasions. It is also determined that the phase conductor leader velocity is larger for a higher voltage class, while the charge density associated with the leader emerging from the phase conductor is smaller for a higher voltage class. (C) 2015 Elsevier B.V. All rights reserved.

关键词： CCO cell culture   Cell growth   Freezing   Hydrolysates   Serum-free medium  

摘要： In this work we describe the adaptation of channel catfish ovary (CCO) cell line to commercially available Ultra Culture serum-free medium by gradual reduction of serum concentration from 10 to 0 %. With this approach we obtained CCO cells fully adapted to serum-free conditions in 32 days. Growth, nutritional and morphological characteristics of these cells remained unchanged when compared to the control group kept in the presence of serum. Additionally, three commercially available protein hydrolysates were tested for the effects on growth performance of the newly serum-free adapted CCO cells. Supplementation with wheat gluten hydrolysate resulted in growth similar to serum free medium solely, while yeast and soy hydrolysates showed inhibitory effects on the cell growth. Taken together, the successful adaptation of CCO cells to serum-free conditions indicates their potential to be used in cytotoxicity assays when serum omission is demanded or for developing serum free bioprocesses using CCO cells. However, a more extended study on nutrient supplementation is still required to further boost the cell growth in a serum free culture.