145 research outputs found

    股指期货最后结算价:国际比较与台湾经验

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    本文对目前全球主要交易所股价指数期货最后结算价的确定规则进行了横向归类和比较,介绍了台湾期货交易所股指期货最后结算价确定规则的历史演变。以我国台湾地区为研究对象,利用拔靴复制检定方法,本文对股指期货最后结算价各种确定规则的效应进行了实证分析,并得到了一系列重要的实证结论

    Crop Morphogenesis and Solutions Under Heavy Metal Pollution

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    在重金属污染愈发严重的背景下,探索出保障污染地区的农业生产水平可持续发展的技术,是保障粮食生产安全亟需解决的重要问题.通过综述农作物对重金属胁迫的形态建成响应机制与实践中的农艺管理技术手段,总结在重金属污染区域提高粮食产量的主要方法.重金属影响下的作物形态建成具有深刻的遗传基础和复杂的生理机制,这就决定了作物对重金属的响应受到作物类型与重金属种类的影响.通过对作物形态建成的更深入研究,建立一套从品种选择到田间管理的应对措施,可以为农业安全生产提供持久有效的保障.In consideration of the fact that agriculture is under increasing risk of heavy metal pollution,it is urgently needed to deve-lop a technology to ensure sustainable food production.Here we review the mechanism of morphogenesis change as a response of crops to heavy metal pollution,the methodology in heavy metal pollution risk assessment and promising agriculture technologies to alleviate the heavy metal stress.The genetic basis and physiological mechanism of crop under heavy metal pollution are complex,and the response depends on plant phylogeny and metal species.With the developing knowledge on morphogenesis response and effective guidance from varieties of choices to field management,the food production in zones polluted with heavy metals will be protected.国家重点基础研究发展计划(973计划)(2013CB956504

    Study on Large Scale Precision Measurement Platform for Optical Aspheric Lens

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    针对光学非球面元件精密面形测量的需要,提出了一种大尺寸精密检测平台的测量与控制技术。通过讨论检测平台离线测量原理,采用高精度直线电机、0.1μM接触式/非接触式测量传感器以及自主开发测量评价软件为核心的软硬件控制方案,完成了大尺寸精密检测平台的设计与搭建,并针对光学非球面元件的测量特点,开发了配套的测量软件,以实现大口径光学非球面元件的面形测量与评价。光学非球面元件的测量实验结果表明:该检测系统可以有效地应用于非球面表面形貌的精密测量。According to the requirement of precision measurement for optical aspheric surface,this paper presents a measuring and control means,which is based on large scale high-precision measurement platform.Through analyzing the off-machine measuring principle,a large scale measurement platform included high-precision linear motors,contacting and non-contacting measurement sensor of 0.1um resolution and a new developed of measuring software,is designed and built.Aiming at the measurement characteristics of optical aspheric lens,measuring software is developed to achieve surface metrology and evaluation for large scale optical aspheric lens.The experiment results indicated that the measuring system has met the needs of high-precision measurement.福建省自然科学基金资助项目(2012J05102); 厦门理工学院高层次人才引进项目(YKJ11029

    Research Progress of Metal Material Liquid Forming Technology

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    随着汽车工业的迅速发展以及市场竞争对铸件质量要求的提高,推动了金属材料液态成型技术发展。从20世纪70年代压铸技术的广泛运用,到90年代挤压铸造技术的不断完善,随后挤压压铸技术不断创新,使液态成型技术向多学科渗透融合发展,应用领域不断拓展,铸件用量逐年上升。重点介绍了压铸、挤压铸造、挤压压铸这三种重要的成型技术发展以及取得的最新成果。With the rapid development of auto industry and the market competition on the increase of the requirement of the casting quality,the development of metal material liquid forming technology was promoted.From the extensive use of the die casting technology in the nineteen seventies to constant maturity of the 90's the squeeze casting technology,and then the continuous innovation of squeezing die casting,the liquid forming technology for multidisciplinary permeated and developed,application area continued to expand,and casting quantities increased year by year.The development and the latest achievements of three kinds of important forming technologies(die casting,squeezing casting and squeezing die casting) were mainly introduced.贵州省(贵阳市)工业攻关项目(黔科合GY字[2012]3004;筑科合同[2012101]2-13号

    丙二酸二甲酯均相催化加氢合成3-羟基丙酸甲酯的研究

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    本文以乙酰丙酮钌和膦胺配体作为催化剂体系,用于催化丙二酸二甲酯加氢制3-羟基丙酸甲酯.围绕催化反应性能,系统探讨了配体结构和用量、温度、时间以及溶剂等对丙二酸二甲酯转化率和3-羟基丙酸甲酯产率的影响.研究发现,乙酰丙酮钌和o-二苯基膦苯胺构成的催化剂体系在合适反应条件下可以有效催化丙二酸二甲酯选择性加氢制3-羟基丙酸甲酯.在优化的反应条件下,这一催化剂体系也可以催化多种不同结构酯类分子加氢制醇

    电针促进胃黏膜损伤修复的时效关系及分子机制

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    目的:动态观察电针对胃溃疡模型大鼠胃黏膜损伤修复的影响,探讨电针治疗胃溃疡的时效关系和分子机制。方法:72只SD大鼠分为空白组、模型组、胃经穴组、对照点组,并按干预时间1、4、7 d分为3个亚组,每个亚组6只。采用乙醇灌胃方法制备胃溃疡大鼠模型,胃经穴组电针\"足三里\"\"梁门\",对照点组电针\"梁门\"\"足三里\"外旁开5 mm处,每日1次,每次电针30 min。空白组和模型组用鼠板束缚但不进行电针处理,每日1次,每次30 min。用逆转录-聚合酶链反应(PR-PCR)法检测胃增殖细胞核抗原(PCNA)、P物质(SP)的表达,Western blot检测胃神经降压素(NT)的表达。结果:干预1 d后,模型组溃疡指数显著高于空白组(P0.05),PCNA m RNA、SP m RNA低于模型组(P0.05)。干预7 d后,各组以上指标组间比较差异均无统计学意义(均P>0.05)。结论:电针胃经穴能在胃溃疡发展的不同病理状态下对PCNA m RNA、SP m RNA进行双向调节的平衡作用同时促进NT蛋白高表达,进而促进溃疡的修复。深圳市科技计划项目:JCYJ 20160406140612883;;国家自然科学基金项目:8147375

    The Analysis and Assessment of Groundwater Quality of Qinhuangdao

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    针对秦皇岛市地下水位下降,环境污染日益严重的现实,开展了以海水入侵区为主的地下水质综合评价与分析。在全市境内布设76眼监测井,用单因子法和综合法对地下水质量进行了评价,并对地下水水质变化趋势进行了分析。研究结果表明:Ⅰ类水只占5.3%,Ⅱ、Ⅲ水占14.5%,Ⅳ类及超Ⅳ类水占到80%以上,其中Ⅴ类水占40%。主要污染物有Fe、Mn、NO3-N、Cl、总硬度等。地下水质监测动态变化显示:总硬度、Cl-、矿化度、F-等呈上升趋势,其中总硬度和Cl-上升达75%,说明海水入侵的影响很大。To conter the situation of increasingly declining groundwater level and environmental pollution,the water quality assessment and analysis of sea water invasion district was studied.76 monitoring wells were laid,a single index method and the method of the comprehensive evaluation were used and the groundwater trends was analyzed.The results showed that the shallow groundwater of Qinhuangdao City meeting the Ⅰcategory water standard accounted for only 5.3%,Ⅱ,Ⅲcategories 14.5%,Ⅳ,Ⅴcategories more than 80%,40% of which wasⅤcategories and that Fe,Mn,NO3-N,Cl,total hardness were the major chemical components.The dynamics monitoring of underground water indicated that total hardness,chlorine,degree of mineralization,fluorine are becoming upward trend,especially total hardness and chlorine increased by over 75%, which means salt water intrusion on the larger impact.河北省自然基金项目(301165

    From 1D zigzag chain to 1D tubular structure, weak field ligand-dependent assembly of cucurbit[6]uril-based tubular coordination polymer

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    通讯作者地址: Long, LS (通讯作者), Xiamen Univ, State Key Lab Phys Chem Solid Surface, Xiamen 361005, Peoples R China 地址: 1. Xiamen Univ, State Key Lab Phys Chem Solid Surface, Xiamen 361005, Peoples R China 2. Xiamen Univ, Dept Chem, Coll Chem & Chem Engn, Xiamen 361005, Peoples R China 电子邮件地址: [email protected] reaction of cucurbit[6]uril with Cu(NO3)(2) and CuCl2, respectively, generates a 1D zigzag chain of {[Cu(H2O)(4)( cucurbit[6]uril)]center dot(NO3)(2)center dot(H2O)(8)}(n) and a 1D tubular structure of {[Cu(H2O)(2)(Cl)(2)(cucurbit[6]uril)](1/3)center dot(H2O)(3)}(n), showing clearly how to control the reversible and mutual interconnections between ligand and metal ion under the guide of coordination chemistry.NNSFC 20825103 20721001 973 project 2007CB815304 Natural Science Foundation of Fujian Province of China 2008J001

    21世纪中国金融学教学改革与发展战略

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    国家教育部新世纪教改工程项目《21 世纪中国金融学专业教育教学改革与发展战略研究》, 目前已取得阶段性成果。2001 年8 月16 日至21 日, 承担该项目的中央财经大学、中国人民大学、厦门大学和复旦大学在青海省西宁市举行了成果交流和研讨会。项目主持人、中央财经大学副校长、金融学博士生导师王广谦教授主持了这次会议, 全国所有有金融学博士学位授权点的高校和科研院所都有代表出席大会, 用主持人的话来说, “全国金融学界顶尖级人物基本上都到了”。出席会议的还有教育部高等教育司刘凤泰副司长和杨志坚处长。与会专家学者回顾了近20 年国内外金融业的迅猛发展, 分析了在21 世纪随着经济全球化、金融国际化对我国经济金融带来的机遇和挑战, 以及对我国金融研究、金融学科建设和人才培养带来的冲击,大家认识到, 经过20 年的改革开放和发展, 目前我国在这些领域虽有长足的进步, 但仍远远不能适应形势发展的要求。要想把我国金融学科建设成国际一流学科, 培养出一流的高素质金融专业人才, 还必须进行一系列改革与创新。与会专家教授根据各自的教学实践, 提出了许多具有建设性的意见。研讨会上发言踊跃、气氛热烈, 不时出现不同观念的碰撞和不同观点的交锋, 对推进金融学科建设十分有益。下面将著名专家教授颇具代表性的观点( 按发言顺序) 择要摘发, 以飨读者, 以推动中国金融学科的建设与繁荣

    Room-temperature quantum interference in single perovskite quantum dot junctions

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    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
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