278 research outputs found

    An Empirical Research of the Oil Future Margin Ratio in China

    Get PDF
    本文在我国原油期货即将推出之际,关注原油期货上市交易风险管理控制的第一道屏障----保证金制度,通过对原油期货这一金融资产交易风险相关的评估,得出我国原油期货上市交易的保证金理论水平和动态调整机制,保证原油期货市场稳定,不断推进我国原油定价权,为我国原油储备等国民基础性物质提供保障。 本文通过研究BRENT原油期现货价格间的长期均衡关系,构建二元t-Copula函数模型,发现BRENT原油期现货价格以及胜利油田原油现货价格两两间不仅存在高度的线性相关关系,同时存在较强的非线性相关关系,且资产尾部相关性较高,对极端事件的反应趋势较为一致,协同程度相对较高。从而构造了基于原油期现货收益率序列下的...The article is attention to theimportment barrier of the risk control of oil future which will be listing transaction in the near future in China.We appraised the risk of oil future’s transaction,one kind of the financial assets,found the theoretical level of oil future margin ratio and dynamic adjustment mechanism,to ensure the market stability,promote the pricing power of China in the internatio...学位:经济学硕士院系专业:经济学院_资产评估硕士学号:1552014115189

    地方神明建构脉络之解读——以陈靖姑信仰为中心

    Get PDF
    陈靖姑信仰是闽、台、浙等地区重要的民间信仰之一,其形象的形成与建构涵盖了非常丰富的历史与文化内涵。通过对文献的解读,我们认识到陈靖姑信仰既是多面相的,又具有正统性的特征,这是其复杂建构过程的反映。在地方神明建构脉络中,国家与地方常常是共谋的关系,陈靖姑信仰固然是多样性的地方文化不断衍生的产物,但同时不可避免地刻上了国家文化一统性的印记

    Empire Periphery: Study on Native Chieftain System of West Guangxi from a View of Historical Anthropology

    Get PDF
    在中华帝国的历史上,相对于“中心”的“边陲”的界定满足于“天下观”的总体构想,并在汉人难以推进的那些“化外之地”实行特殊的行政体制,即羁縻体制,至元明清发展为土司制度。桂西正是这样的边陲之边陲。然而明清土司制度的推行在这一地区产生了深刻的社会影响。 土司制度实际上是中央王朝“天下观”的“中心—边缘”结构的实践,这种具有强烈“汉人中心主义”的思想意识成为边陲挥之不去的情结。土司力图形塑一个国家政权的“正统”代理人的文化形象,将中心分解到边缘,借此稳固其权力和统治,并以组织性以及象征性的方式溶入到土司社会权力的文化网络建构之中,再造一个中心与边缘的政治格局。因此土司“权力的文化网络”建构过程实际...The panoramic imagination on world distinguished“center”and “border” territorially and culturally in the history of imperial China,which resulted in special non-Chinese polity i.e. jimi System, and later native chieftain system over those “uncivilized areas” in border provinces in the Yuan, Ming and Qing Dynasties. Exactly, West Guangxi is located in the “border”of border regions, which was also...学位:法学博士院系专业:人文学院人类学研究所_人类学学号:2005140324

    生态人类学概论

    Get PDF
    生态人类学是20世纪后逐渐形成的一门人类学分支学科,特别注重在理论和实践上探讨文化与环境之间的复杂关系。这样的研究取向在整个学科的发展过程中得到了充分体现,生态人类学家对文化与环境关系不同的表述和侧重构成了多种理论和观点。文章对生态人类学的产生与发展及各种理论进行了简要的论述,为深化其实证性研究提供参考

    Delay-Constrained Mobile Energy Charging in Wireless Sensor Networks

    Get PDF
    为了延长无线传感网的生存期,基于可充电的移动设备,研究设计了一种无线传感网中移动式能量补充的方法,移动节点可以在为传感器节点补充能量的同时收集数; 据.首先,通过将无线传感器网络监测区域分割为大小相同的子区域,该子区域内的节点组成一个簇;其次,以一个簇内的总能量为计算依据,设计移动节点的路径; 生成算法以确定能量高效的移动路线;最后,使用10种不同的随机网络拓扑图进行了仿真实验,以节点移动速度和时延为限制条件分别得到了对比数据.结果表明; ,本文提出的算法与NJNP( nearest-job-next with preemption)算法相比在时延相同的条件下( 800; s),生存期提升了6 000 s左右,在节点速度5 m/s条件下生存期提升了将近14 000; s.证明本文所提方法有效地提高了充电效率,延长了网络的生存期,可用于大规模的无线传感器网络.In order to prolong the lifetime of wireless sensor networks by using; energy-rechargeable mobile devices,this paper designs a mobile energy; replenishment method wherein a mobile element gathers data and recharges; sensors simultaneously. Firstly,the whole sensor network is divided into; several sub-regions equally and the sensors in each sub-region are; formed into a cluster. Secondly, considering the energy in a whole; cluster,the mobility path is designed to find the energy-efficient; mobile trace of the mobile element. Finally,in the simulation; experiment,we used ten different random network topologies to show the; comparisons with extensive simulation experiments under different; velocities and deadlines. The results indicate that the proposed; algorithm increases lifetime by approximately 6 000 s compared with; Nearest-Job-Next with Pre-emption( NJNP) under the deadline of 800 s.; Moreover,the proposed algorithm increases lifetime by approximately 14; 000 s compared with NJNP at velocity of 5 m/s. Thus,the proposed; algorithm can improve recharging efficiency and prolong the lifetime of; wireless sensor networks,which can be used in large-scale sensor; networks.国家自然科学基金资助项目; 福建省高等学校杰出青年科研人才培育计划资助项

    Rapid determination of 1,2-propylene glycol and glycerol in refill fluids for electronic cigarettes by Raman spectroscopy

    Get PDF
    为实现电子烟烟液主要成分的简便快速检测,建立了同时测定电子烟烟液中1,2-丙二醇和丙三醇含量的拉曼光谱分析方法,利用该方法测定了17个电子烟烟液; 样品,并与气质联用法进行了结果比较。结果表明:①1,2-丙二醇和丙三醇分别在0.125~0.956和0.106~1.120; g/mL时,以522和671 cm~(-1)特征信号峰强度绘制的标准工作曲线线性关系良好(R~2>; 0.999),单样本和独立样本t检验结果证实方法的准确性较高。②17个电子烟烟液样品中,1,2-丙二醇和丙三醇的含量分别为0.533~0.766; 和0.182~0.476; g/mL。该方法与气质联用法检测结果的配对样本t检验结果表明,在95%置信概率下,两种方法的定量结果一致。该方法不需进行样品前处理,更适用于批量; 电子烟烟液中1,2-丙二醇和丙三醇的快速定量分析。A simple and rapid Raman spectroscopy method for simultaneous; determination of 1,2-propylene glycol and glycerol in refill fluids for; electronic cigarettes was developed. Samples of 17 refill fluids were; analyzed by a portable Raman spectrometer,and the data were compared; with those determined by GC-MS. The results showed that: 1) The standard; curves of 1,2-propylene glycol and glycerol determined at the Raman; intensity of 522 and 671 cm~(-1) possessed good correlation coefficients; (R~2 above 0.999) in the content range of 0.125-0.956 and 0.106-1.120; g/mL,respectively. The results of one sample t-test and independent; sample t-test indicated that the Raman method was accurate. 2) The; contents of 1,2-propylene glycol and glycerol in 17 refill fluids were; in the range of 0.533-0.766 and 0.182-0.476 g/mL, respectively. The; result of paired sample t-test showed that the data determined by Raman; spectroscopy were consistent with those obtained by GC-MS at a; confidence level of 95%. Without sample pretreatment, Raman spectroscopy; method is simple to operate and more suitable for the rapid quantitative; determination of 1,2-propylene glycol and glycerol in batches of refill; fluids for electronic cigarettes.浙江中烟工业有限责任公司科技项

    Room-temperature quantum interference in single perovskite quantum dot junctions

    Get PDF
    钙钛矿材料由于其高量子产率、载流子迁移率和独特的光致发光特性而在光电材料领域存在诸多潜在的重要应用。研究钙钛矿材料在纳米尺度下电荷输运的独特尺寸效应对钙钛矿光电器件的设计和开发具有重要的指导意义。洪文晶教授课题组基于机械可控裂结技术自主研发了具有皮米级位移调控灵敏度和飞安级电学测量精度的精密科学仪器,对南开大学李跃龙副教授团队合成的钙钛矿量子点进行了深入表征,研究工作成功将量子干涉的研究体系拓展至在光电领域具有重要应用的钙钛矿材料领域,为未来制备基于量子干涉效应的新型钙钛矿器件提供了一种全新的思路。 这一跨学科国际合作研究工作是在化学化工学院洪文晶教授、英国Lancaster 大学物理系Colin J. Lambert教授以及南开大学电子信息与光电工程学院李跃龙副教授的共同指导下完成的。化工系硕士研究生郑海宁、Lancaster University大学Songjun Hou博士、南开大学硕士研究生辛晨光为论文第一作者。博士后林禄春,博士研究生谭志冰、郑珏婷,硕士研究生蒋枫、张珑漪,本科生何文翔、李庆民等参与了论文的研究工作。刘俊扬特任副研究员、师佳副教授和萨本栋微纳米研究院杨扬副教授也参与了部分指导工作。The studies of quantum interference effects through bulk perovskite materials at the Ångstrom scale still remain as a major challenge. Herein, we provide the observation of roomtemperature quantum interference effects in metal halide perovskite quantum dots (QDs) using the mechanically controllable break junction technique. Single-QD conductance measurements reveal that there are multiple conductance peaks for the CH3NH3PbBr3 and CH3NH3PbBr2.15Cl0.85 QDs, whose displacement distributions match the lattice constant of QDs, suggesting that the gold electrodes slide through different lattice sites of the QD via Auhalogen coupling. We also observe a distinct conductance ‘jump’ at the end of the sliding process, which is further evidence that quantum interference effects dominate charge transport in these single-QD junctions. This conductance ‘jump’ is also confirmed by our theoretical calculations utilizing density functional theory combined with quantum transport theory. Our measurements and theory create a pathway to exploit quantum interference effects in quantum-controlled perovskite materials.This work was supported by the National Key R&D Program of China (2017YFA0204902, 2014DFE60170, 2018YFB1500105), the National Natural Science Foundation of China (Nos. 21673195, 21503179, 21490573, 61674084, 61874167), the Open Fund of the Key Laboratory of Optical Information Science & Technology (Nankai University) of China, the Fundamental Research Funds for the Central Universities of China (63181321, 63191414, 96173224), and the 111 Project (B16027), the Tianjin Natural Science Foundation (17JCYBJC41400), FET Open project 767187—QuIET, the EU project BAC-TO-FUEL and the UK EPSRC projects EP/N017188/1, EP/M014452/1. 该工作得到国家重点研发计划课题(2017YFA0204902)、国家自然科学基金(21673195、21503179、21490573)、厦门大学“人工智能分析引擎”双一流重大专项等项目的资助,也得到了固体表面物理化学国家重点实验室、能源材料化学协同创新中心的支持
    corecore