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Search Results: 1 - 10 of 28288 matches for " 田珺 "
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张拉膜结构形状确定的实验研究
叶继红,
工程力学 , 2010,
Abstract: 在膜结构找形中,力密度法引入了“力密度”的概念,使问题简化。但力密度法需要多次试算后才能确定合适的力密度取值,这给找形过程带来困难。该课题组对力密度法的找形过程进行改进,避开其中“力密度”的概念,使找形计算过程简洁高效。该文即对这种“改进力密度”法进行了试验研究,以验证该方法的正确性。试验模型为一平面尺寸为4m×4m柔性索边界、四点支承的马鞍形张拉膜结构。张拉过程采用应力和位移同时控制,量测模型零状态、中间状态和张拉成形后状态边索和膜面的应变值及膜面监测点的空间坐标。通过试验值与理论值在膜面应变、索应变及膜面空间坐标的比较及与ANSYS法、解析法的比较,说明改进力密度法是正确的,可用于实际工程的膜结构找形分析。另外,通过本次实验,我们对膜面应变的量测也得到了一些经验教训。
区域水资源可持续利用指标体系及评价方法的研究进展
Evaluating Index System and Methods of Regional Water Resources Sustainable Utilization
 [PDF]

, 门宝辉, 屈承, 刘焕龙, 吴智健, 白婉欣
Journal of Water Resources Research (JWRR) , 2016, DOI: 10.12677/JWRR.2016.53031
Abstract:
水是生命之源,是人类生存和社会经济可持续发展的基础,鉴于目前水资源供需矛盾加剧、利用效率低下、水环境恶化等问题日益凸显,水资源的可持续利用受到严峻的挑战,因此,研究区域水资源可持续利用的指标体系及其评价成为当务之急。在正确地认识水资源的现状及发展趋势的基础上,对水资源的可持续性进行准确的评价成为重中之重。通过对近年来国内外水资源可持续利用评价领域的多种体系进行总结,从指标体系的构建方法和评价方法两个角度进行归纳,指出了目前指标体系构建方法的可操作性仍存在不足,特征指标仍存在相对局限等问题,同时对目前的评价方法进行了分析,认为主观赋权易于实现,但精度差,客观赋权能较全面地利用数据,但过于繁琐,而诸如神经网络的不赋权法操作简单易行,但结果过度依赖于已有数据样本集。通过对国内外水资源可持续利用评价体系中存在的问题和发展趋势的梳理和归纳,以期引发对区域水资源可持续利用研究的新思考,推动水资源可持续利用评价体系及其评价方法的改进和完善。
Water is the source of life and on which human being exists and social economy develops sustainable. There still remain many problems challenging the sustainable water resource utilization, such as imbal-ance between the demand and the supply, the low efficiency utilization and the worsening water envi-ronment. So the studying of evaluating index system and methods of regional water resource sustainable utilization becomes the prior problem to solve. On the base of realizing the current situation and devel-oping tendency, the accurate evaluation of the sustainability of water resources is attached more and more important. By leaning the summary of lots of systems in evaluating the sustainability of domestic and foreign, the problems of methods and index system are summarized. It is pointed out that there remain problems that it’s still something wrong with the method to build the index system and that there’s limitation in characteristic index. Simultaneously, by analyzing the present evaluation method, it is ad-mitted that subjective weighting is easy to realize but with a comparatively worse accuracy, while objec-tive weighting can utilize the data completely but is too fussy to operate it. No-weighting method like ANN is easy to operate, but it mostly depends on the fake data. At last, the problem and development tendency are summarized to attract some new opinions of studying the sustainable regional water resources utilization and push the improvement of the evaluation system of sustainable water resources utilization.
上海市“单独两孩”生育政策实施的初步评估及展望
彭希哲,李赟,宋靓,烁 ?
期刊检索-中国人口科学 , 2015,
Abstract: 2014年,29058个上海市户籍育龄家庭申请二孩生育,其中16639户为单独二孩家庭。文章主要根据上海市2014年二孩生育申请数据,描述再生育申请夫妇的人口、经济与社会基本特征,估算再生育申请的累积概率,预测单独再生育夫妇二孩生育的规模和发展趋势,并利用相关资料分析影响再生育申请的主要因素,对上海市乃至全国全面放开两孩生育政策的可能性和潜在影响进行实证分析和初步研判。结果表明,“单独两孩”政策敏感群体的主要特征为:原籍地是上海本地、受教育程度较高、第一孩是女孩,而生育二孩对家庭经济状况的压力及子女照料能力是影响再生育申请的主要因素。上海单独再生育申请存在一定的“赶生”现象,但比例较小。文章预测上海市已生育一孩的家庭中有近1/3最终会提出再生育申请。
基于身份的带凭证部分委托代理多重签名方案
秀霞,曹珍富,叶文
电子学报 , 2006,
Abstract: 本文基于椭圆曲线上的双线性对性质,提出了一个基于身份的带凭证部分委托代理多重签名方案,该方案具有强不可伪造性、强不可否认性、强可识别性和预防误用性.
聚合物驱油剂的性能变化规律研究(I)——聚合物驱油剂的热稳定性研究
Study of Performance Changes of Polymer Flooding Agent (I)——Study of Thermal Stability of Polymer Flooding Agent
 [PDF]

朱玥
Open Journal of Nature Science (OJNS) , 2013, DOI: 10.12677/OJNS.2013.12003
Abstract:
本文采用红外、动态光散射、流变、荧光技术,研究了老化时间、模拟水矿化度、老化温度对水溶性疏水缔合聚合物本体结构和溶液性质的影响,探讨了分子组成、构象变化对分子间缠结、疏水缔合等结构的作用,建立了不同矿化度下水溶性疏水缔合聚合物溶液的温度、老化时间相关的热降解二元动力学方程。实验结果表明,疏水缔合结构的存在使其在发挥抗盐、增稠作用时能够经受一定时间的考验,老化引起的水解程度的适度增加反而有利于聚合物的增粘性。
The effect of aging time, water salinity, and aging temperature on the structure and aqueous behavior of the water-soluble hydrophobically associating polymer is investigated by FTIR, DLS, rheological and fluorescence technologies. The influence of macromolecular composition and conformation on intermolecular entanglement and hydrophobically associating are explored. For different salinities, the thermal degradation binary kinetic equation with aging time and temperature are established. The results show that after shearing, the thickening effect will rise up in a certain time, due to the hydrophobically associating structure. And the thickening property is enhanced by moderate increase of hydrolysis level caused by aging effect.
“小人物”的悲剧人生——契诃夫《小公务员之死》和巴金《寒夜》的比较分析
Comparison between “Cold Night” and “The Death of a Small Civil Servant”
 [PDF]

卓煜
World Literature Studies (WLS) , 2014, DOI: 10.12677/WLS.2014.21002
Abstract: 中国现代著名作家巴金40年代创作的反映抗战时期平民生活的小说《寒夜》是其写“小人物”形象的巅峰之作。小说一改作者过去多写青年革命者和封建大家庭的题材,把笔触投向社会底层的受压迫者,描写他们的悲剧人生。在这种风格沉闷化的转变中,我们似乎听到了俄国杰出的现实主义作家——-契诃夫式的叹息。本文以契诃夫短篇小说《小公务员之死》和巴金被誉为“掌握了契诃夫现实主义精髓”的《寒夜》为例,比较分析两部同样叙写了“小人物”悲鸣与哀叹小说的相似点和差异This paper mainly discusses two famous novels. One is Chinese novelist—Ba Jin’s novel called “Cold Night”; the other is a novel written by Anton Chekhov, named “The Death of Small Civil Servant”. These two novels are of great importance in the history of realistic literature. The famous modern Chinese writer Ba Jin created the long novel “Cold Night” in 1940s, during the period of anti-Japanese war. As the author said, “Cold Night” is written for “nobody”, who is struggling in poverty. Ba Jin’s writing style changed from the passive one which is full of energy to the society, to a new one, that is, more realistic, negative but tells the tragedy of poor people. This shift seems to follow the Russian outstanding realistic writer—Anton Chekhov’s stlye. According to the Chekhov short story “The Death of Small Civil Servants”, we find many things in common between the two fabulous novels. In this paper, the author will make a comparative analysis of the two novels, and will also demonstrate the similarities and differences between these two novels and the two great writers.
系统理论视角下探析多校区高校图书馆管理
The Analysis of Multi-Campus University Library Management Based on System Theory
 [PDF]


Management Science and Engineering (MSE) , 2015, DOI: 10.12677/MSE.2015.42006
Abstract:
本文对多校区高校图书馆在管理中存在的问题进行分析,在系统管理理论的视角下探析解决多校区高校图书馆管理问题的方法,需要以人为本、促进人力资源管理的创新,并关注图书馆与环境的关系,加强与其他图书馆的交流,促进多校区图书馆的长期发展。
This paper analyzes the problems in library management of multi-campus university and tries to find some ways to solve the problems under the perspective of system management theory. Uni-versities should be more people-oriented to enhance innovation in human resource management. They can focus on the relationship between library and environment, increase the frequency of communication with other libraries, and promote the long-run development of multi-campus uni-versity library.
家庭联产承包责任制对我国农业集约型规模经营的影响
The Effect of the Household Contract Responsibility System to Intensive Agricultural Scale Operation of Our Country
 [PDF]


Advances in Social Sciences (ASS) , 2015, DOI: 10.12677/ASS.2015.42013
Abstract:
家庭联产承包责任制的小农经营的特点造成目前我国农业生产效率较低的状况,本文结合世界发达国家的经验,提出在我国发展农业集约型规模经营。但家庭联产承包责任制在一定程度上制约了发展农业集约型规模经营,文章从家庭联产承包责任制角度下研究我国农业集约型规模经营发展的问题及对策,以及相应政策实施中的利益冲突。
The characteristic of the household contract responsibility system is small-scale business in farm- ing that leads to the low efficiency of agricultural production in our country. This paper puts for-ward the suggestions of developing the intensive agricultural scale operation in our country com-bining with the experience of the developed countries. But to some extent, the household contract responsibility system also brings some problems for putting into practicing the intensive agricul-tural scale operation. This article analyzes the problems and countermeasures for intensive agri-cultural scale operation in our country under the household contract responsibility system, in-cluding the conflict of interest in the policy.
1976—2007年青海省刚察县土地沙漠化驱动力分析
丽慧, 张登山, 胡梦, 鲁瑞洁
中国沙漠 , 2013, DOI: 10.7522/j.issn.1000-694X.2013.00067
Abstract: 土地沙漠化是青海湖沿岸地区最严重的生态环境问题之一。本文选取青海湖北岸的刚察气象站1958—2007年的气象数据和刚察县1976—2007年的社会经济资料,对近30年来刚察县土地沙漠化的驱动力进行主成分分析。结果表明,1976—2007年,刚察县沙漠化土地面积的增加是自然因素和人为因素综合作用的结果,尤以年平均风速和耕地面积变量的贡献率最大。刚察县沙漠化土地的扩张在不同时间段的影响因素不同。1976—1987年,沙漠化面积的扩张是气温逐渐回暖、降水回升的过程中人为因素影响的结果;1987—1995年,沙漠化土地增加了17.28km2,沙漠化土地的扩张是自然因素和人为因素叠加的结果,以自然因素为主导,人为因素起加剧的效果;1995—2007年,在暖湿、风速降低的气候环境下,沙漠化土地的扩张是人为因素作用的的结果。沙漠化扩张过程是高寒脆弱不稳定的生态系统在气候干湿波动、人类活动与沙漠化土地之间复杂的相互反馈作用下形成的。
遥感与GIS支持下近30a来青海湖环湖区土地沙漠化动态变化研究
胡梦, 丽慧, 张登山, 李 森, 高尚玉
中国沙漠 , 2012,
Abstract: 青海湖环湖区是青藏高原土地沙漠化最为严重的区域之一。基于RS和GIS技术,选取1976、1987、1995年和2006年4期遥感影像,利用ERDAS的图像和信息处理功能对环湖区1.43万km2的土地进行专题信息提取,采用室内解译和野外检验修正的方法重建了环湖区近30a来的沙漠化土地时空动态变化和分异格局,并在此基础上预测了未来20a沙漠化土地的发展趋势。研究结果表明,近30a来本区沙漠化在时间上表现为快速增加-缓慢上升-快速增加的持续扩展过程;在空间上由少成片分布或多零星分布向以4大沙区为主、滨湖沙堤为连线的环湖带状分异格局演变。受气候变化、人类活动和人工治理的综合影响,未来20a该区沙漠化面积在前15a呈增长趋势,后增长缓慢并出现逆转。
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