293 research outputs found
The Synthesis of Advantame
Advantame是一种新型的高效二肽甜味剂,它的甜度是蔗糖的20,000倍,并且具有甜味纯正、不含热量、性质稳定等优点。Advantame现已通过美国食品药品监督管理局(FDA)食品安全认证,是甜味剂研究的又一重要成果。目前,Advantame的合成过程一般分为两步,先采用异香兰素和乙醛通过羟醛缩合反应生成中间体3-羟基-4-甲氧基肉桂醛,再将中间体与阿斯巴甜通过还原胺化反应生成Advantame。由于异香兰素和乙醛的羟醛缩合反应需要在低温下进行,而且耗时长、收率低,因此Advantame的合成过程亟待优化。 本论文以异香兰素为起始原料,经羟醛缩合反应合成了中间体3-羟基-4-甲氧基肉桂醛...Advantame is a novel high-intensity sweetener and its sweetness is 20,000 times sweeter than sugar’s. Advantame has no calories and an outstanding flavor profile. Nowadays, Advantame has got approved of the FDA and it’s the latest achievement of sweeteners research. The synthetic process of Advantame can be concluded into two reactions including the aldol condensation reaction to synthesize 3-hy...学位:工学硕士院系专业:化学化工学院_化学工程学号:2062014115144
Ternary Distillation Drying Process with Pore Protection and Its Applications
多孔材料应用广泛,其孔道特性对其应用过程中表现的性能具有很大影响。而在多孔材料的制备过程中,干燥方式对产品性能的影响极大,因而选择合适的干燥方法尤为重要。虽然工业上已经有超临界干燥、冷冻干燥、共沸蒸馏等护孔干燥方法,但仍然存在不同的问题。为此,本论文工作在共沸蒸馏的基础上,提出含有置换剂+改性剂+水的三组分蒸馏护孔干燥作为多孔材料干燥的一种方法,以SiO2等系列多孔材料的干燥为对象,系统研究所提出的干燥方法;进一步研究MgO多孔材料的干燥和应用,并与超临界干燥获取的产品进行比较。 以碳化法制备的二氧化硅浆料等系列多孔材料浆料为对象,探索三组分蒸馏护孔干燥的工艺条件。研究表明,三组分蒸馏护孔干...Porous materials are widely applicable, and the pore properties indeed affect their applications. Drying process in preparing porous materials is a key step for preserving the materials to a great extent on pores; so choice of an appropriate drying process is very important. Although there are some drying processes with pore protection in industry, such as, supercritical drying (SCD), freeze dryin...学位:工学硕士院系专业:化学化工学院_化学工程学号:2062014115139
Synchronous Fluorescence Spectroscopic Technique for the Simultaneous and Rapid Determination of Polycyclic Aromatic Hydrocarbons in Vegetable Oils and the Preliminary Study of Its Coupling with Surface Plasmon-Coupled Emission
同步荧光技术(synchronousfluorescencespectrometry,SFS)是一种基于激发、发射波长仪彼此间保持一定的关系进行同时扫描而获得荧光光谱的一种荧光分析技术。因其具有简化光谱、减少光散射、提高选择性和灵敏度等优势,已逐渐发展成为多组分体系快速检测的有力工具。表面等离子体耦合发射荧光(surfaceplasmon-coupledemission,SPCE)是利用金属近场作用范围内的受激分子与金属表面等离子体之间的耦合作用而建立起来的一种新型的界面增强技术。凭借其定向发射性、偏振性、波长分辨性、能排除远场背景信号干扰等优势,SPCE检测方法的研究和应用得到了迅猛发展。本...Synchronous fluorescence spectrometry (SFS) is a fluorescence analysis technique based on the definite relation between the excitation and emission wavelengths in the process of simultaneous scanning to obtain the fluorescence spectrum. Owing to its advantages of simplified spectrum, less light scattering, high selective, and sensitive, SFS has been gradually developed to a powerful tool for the r...学位:理学硕士院系专业:化学化工学院_分析化学学号:2052013115156
Genre Analysis on Legal Liability of Test Drive Accidents
在汽车交易市场上,汽车买主在决定购买汽车之前,往往需要进行试驾。通过试驾,买主可以测试汽车性能,以最终决定是否购买。近年来,在竞争激烈的汽车销售大战中,试驾已成为经销商取悦消费者的一种常用的营销手段,但是在现实的交易过程中,因试驾引发的交通事故连见诸报端,其中关于试车格式条款的效力及赔偿责任分配的争议引起了业界的关注。 目前对于试驾事故发生后所涉及的法律问题,比如试乘试驾协议中格式条款效力的认定、违约责任和侵权责任竞合、以及试车事故中责任的分配等,理论界已有针对以上问题的研究成果。但对于试驾事故中的相关法律问题,国内目前还没有以案例为基础、以理论为支撑的综合性分析。因此笔者以此题作为毕业论文...Car buyers usually take a test drive before they decide to purchase in car trade market. Through test drive, potential buyers can test the performance of the car before they make the final decision. Test drive is a will forming process before the two parties make a contract. In recent years, test drive has become a common and effective management to entertain the customers in fierce car market. Ho...学位:法律硕士院系专业:法学院_法律硕士学号:1302012115022
Study on Providing Mechanism Innovation of Public Services in Nanchang
近年来,公共服务体制机制创新问题成为公共管理研究的一个热门话题。各级地方政府在建设服务型政府的过程中,不断完善公共服务体制,尝试创新公共服务提供机制。南昌市作为一个中部正在崛起的城市,虽然经济持续增长,人民生活水平日益提高。但公共服务的制度改革明显滞后于经济发展进程,致使一些社会矛盾和社会问题不断增加。为了提高南昌市公共服务水平,推动服务型政府的建设,全面、系统地研究南昌市公共服务提供机制创新问题成为当下较为迫切的任务。 本文通过对南昌市公共服务提供机制的创新实践进行了整合和梳理,得出南昌市提供机制创新的市场化和社会化推进路径。在此基础上提炼出南昌市在创新公共服务提供机制中的有效经验,归纳出...In recent years, the research of public service system and mechanism innovation becoming a hot topic. Local governments which in the process of building a service-oriented government continuously make efforts to improve the public service system, and try to innovate the public service mechanism. Nanchang emerging as a central city, sustained economic growth, increasing the level of people's life...学位:管理学硕士院系专业:公共事务学院公共管理系_公共政策学号:1392008115094
In-situ Raman Observations on Domain Switches under a DC Electric Field and Phase Transitions of PLZT Ferroelectric Ceramics
Raman光谱与铁电体中的晶格振动模相关,能从晶格动力学的角度反映铁电体中畴变与相变的物理本质。本项工作运用Raman散射光谱技术,建立了对PLZT铁电陶瓷的相变及直流电场下的电致畴变进行原位观测的方法和装置,对未极化和经过极化的两种PLZT试样在温度变化过程中的相变现象和外电场作用下的畴变行为进行了系统的观测;探索了铁电陶瓷材料的Raman光谱的分峰拟合方法,并利用该方法获得了各晶格振动模的强度与温度及外加直流电场之间的变化规律。 不同温度下的电滞回线测试表明,在温度约320℃处试样的电滞回线消失,即在该温度点发生铁电至顺电相变。而高温原位Raman观测结果表明,随着温度的升高,Raman...Since Raman spectrum is closely related to the lattice vibrations of ferroelectrics, it may be used to investigate the essence of domain switches and phase transitions of ferroelectrics from the perspective of lattice dynamics. In this work, an in-situ, nondestructive method and experimental setup for Raman observations of phase transitions and electric-field-induced domain switches of PLZT at mic...学位:工学硕士院系专业:化学化工学院材料科学与工程系_材料物理与化学学号:20043601
重庆公交体制改革的“多源流”视角
多源流分析模型是用来解释政策如何制定的一种方法,它将政策过程中的影响因素分为问题、政策、政治三大源流,认为“政策之窗“的开启使三个源流汇聚在一起,从而使问题提上政策议程。多源流理论是比较有创见和发展潜力的前沿理论,对于现实中的案例有很好的解释力,因此本文主要用该理论对重庆公交体制改革的政策过程做一个分析
The Optimal Arbitrage Strategy in Stock Index Futures: A Concept Based On American Option
内容摘要 本文希望通过一种美式期权的角度来寻找最优的股指期货套利策略,即求解最优的建立套利头寸与提前结束套利头寸的时机。具体方法是使用数值方法求初步解出期货合约到期前每个时点上不同可套利空间ε对应的美式期权的解,与直接执行期权的收益进行比较,假如大于该收益则不执行期权,假如小于该收益则执行期权,即出现了最优的交易机会。 第一部分是文献综述与问题的提出; 第二部分引入三种美式期权的概念并阐述三者之间的关系; 第三部分主要说明股指期货定价模型理论框架,包括偏微分方程与主要的边界条件的推导; 第四部分对台湾2007-2008年的股票指数的现货与期货交易数据进行描述,并利用各个合约的历史交易...Abstract This article is concentrated on the pricing of American option which appeared in stock index futures market. It’s composed of seven parts below, Firstly, review Literature and issues. Secondly, Expatiating the concepts of threes kinds of American option and connection among them. Thirdly, Mainly narrating framework of mould of pricing of stock index futures,including the interpretati...学位:经济学硕士院系专业:经济学院金融系_金融工程学号:2005130097
Minimizing dependency distance in understanding of ambiguous structure
用依存句法分析汉语歧义结构发现人脑在句法加工时倾向选择最小化依存距离的句法结构。该发现从依存理论角度解释了以往依照短语结构句法分析潜在歧义结构“VP+n1+的+n2“无法说明心理学实验结果的原因,找到了歧义结构实时阅读过程中倾向选择特定句法结构的语言学依据。最小化依存距离的认知机制是降低言语工作记忆成本的有效方法,是言语理解过程中的重要机制之一。Human beings tend to choose the structure with the minimum dependency distance during ambiguous structure understanding in order to reduce the burden on working memory.This paper reanalyzes the psychological experimental results within the framework of dependency grammar.The measurement of dependency distance provides the linguistic criteria for why is the potential ambiguity structure"VP + N1 + the + N2"considered as the Modifier-Noun Construction(MNC)rather than Narrative-Object Structure(NOS).Minimizing dependency distance is an important mechanism during natural language understanding and an effective way to reduce the memory cost.国家社会科学基金重大项目(No.11&ZD188
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