Studies on the Synthesis and Purification Process of Oakmoss’s Main Aromatic Component

橡苔是一种地衣类植物，香气浓郁醇厚，其浸膏和净油被广泛应用于各大知名品牌的香水中。但由于天然提取物本身品质不一且含有不易除去的致敏分子，且售价高昂，导致橡苔提取物市场应用受限。为保持原有香水的气味辨识度，香水公司仍需添加该味香料，所以急需人工合成的橡苔主香成分代替天然提取物。人工合成橡苔主香成分的市场价格不菲，开发橡苔主香成分的工业化生产工艺具有较大的研究意义和经济效益。 橡苔的主香成分为3，6-二甲基-β-雷琐酸甲酯。目前，国内外报道该化合物的合成方法主要包括三种：以间苯二酚衍生物为原料，经甲基化和甲氧羰基化等反应制备目标产物；以丙二酸二乙酯和4-己烯-3-酮为原料，经分子内合环及芳构化反...Oakmoss is a kind of lichen with unique fragrance, and its resinoids and absolutes are widely used in the famous brands of perfume as basic fragrance. However, due to the different quality and sensitizing components which are not easy to remove, the use of oakmoss extracts is limited. To keep the identificated smell of perfume, most companies still need to add these flavor, so artificial synthesis...学位：工学硕士院系专业：化学化工学院_化学工程学号：2062014115138

The feasibility of developing low-cost airline in China

上个世纪九十年代以来，以美国西南航空公司为代表的低成本航空赢利模式在世界各地推行，并获得巨大的成功，影响和改变了整个行业的基本架构和发展方向。随着我国民航体制改革步伐加快，政府对航空业的管制逐步放松，低成本航空公司也呼之欲出。本文第一章系统地描述低成本航空公司赢利模式的特征，揭示这种赢利模式成功的原因在于：市场定位（短程休闲和商务旅客）与产品特征（低票价，简单服务，高密度航班和高准点率）、运营方式（统一波音737机型，高日利用率，二级机场）的完美结合。第二章简要介绍我国民航业的发展状况，通过与国外航空公司的成本比较和赢利模式比较，分析我国航空公司成本较高的主要原因：一是管理体制、税收等因素影响...Since the late of last century, the business model of low-cost airline represented by Southwest Airlines spread all over the world, influences and changes the framework and development of the world aviation industry. Along with the reform of Chinese civil aviation, the domestic air services were deregulated gradually. Some of low-cost airlines are coming into being. The first chapter of the paper ...学位：工商管理硕士院系专业：管理学院工商管理教育中心_工商管理硕士(MBA)学号：X20001504

生物技术在垃圾渗沥液处理中的应用

综述了土壤生物处理、生物反应装置处理、微生物强化、膜生物反应器和高效脱氮等生物技术在垃圾渗沥液处理中的应用研究,提出了存在的问题以及今后研究的重点

五氯化磷辅助下氨基酸的自组装成肽反应研究

L α 氨基酸和D α 氨基酸可与五氯化磷直接发生磷酰化反应 ,随后自组装成多肽 ,但 β 氨基酸不能成肽 ,DL α 氨基酸成肽困难 ;在SOCl2 存在下 ,α 氨基酸也不能成肽 .用电喷雾质谱研究了氨基酸的自组装反应 .反应过程中有五元环状的氨基酸五配位磷中间体生成 ,使用硅烷基保护的氨基酸 ,在 3 1PNMR中可观察到五配位磷中间体

Application of Membrane filtration in the Process of Vitamin B_(12) Production

采用聚偏氟乙烯(PVDF)中空纤维微滤膜对维生素B12发酵液进行了除菌研究.发酵液经过微滤膜过滤后,菌体完全去除(去除率100%),远高于离心机除菌效果(去除率70%),滤液的澄清度及质量得到提高.另外,对污染膜的清洗研究表明,一般情况下0.1%的NaOH溶液清洗效果理想,当污染严重时,超声波振荡清洗效果最有效.The vitamin B12 fermentation liquor was treated with PVDF hollow fiber microfiltration membrane in order to remove bacteria.The results show that bacteria were removed completely by microfiltration membrane,and the clarity and quality of filtration liquor was better than that of solution from centrifuge.Moreover,membrane cleaning result indicates that 0.1% NaOH solution has a better efficiengy to recover the membrane flux generally,but ultrasound cleaning technology was most effective when the membrane fouling was serious

Design of wireless remote control system in loaders

为了提高在不安全或环境恶劣的机车调车作业现场的安全性、方便性及其作业效率,以厦工装载机为实验平台,开发设计一种应用于工业现场,具有远距离、高可靠性的多路无线遥控系统。该遥控系统由发射、接收和驱动控制三部分组成,提供无线键盘操作控制与PC机界面独立操作控制的两种遥控模式,同时,软件部分采用了模块化结构设计方法。经过多次现场调试实验,其结果表明,该遥控系统具有较强的实用性,另外,经过改进也可用于其他设备的控制,有较好的扩展功能。Aiming at improving security,operational efficiency and convenience of the field shunting locomotive that work in unsafe or poor environment,a multiple wireless remote control system applied in the industrial field of long-distance and high reliability was developed and designed with XG loader for the experimental platform,the wireless remote control system was made of three parts including the transmitting,the receiving and driving control,a dual wireless remote control mode that through the wireless keyboard or the PC was provided,a modular structural design method was used in the software part.Many on-the-spot debugging test was carried.The results indicate that the remote control system has strong practical,furthermore,the improved can also be used to control other devices,which has good scalability

土地利用变化的经济作用机制分析

土地利用变化动力学研究对于揭示土地利用与土地覆被变化的原因、过程、预测以及相应的对策制定至关重要。集约度变化和用途转移构成土地利用变化的两种基本类型,以新古典的边际分析为工具,土地经济学的集约度理论和地租理论所构成的体系解释了在经济活动中土地利用的状态均衡及其变化

土地利用变化的经济作用机制分析

土地利用变化动力学研究对于揭示土地利用与土地覆被变化的原因、过程、预测以及相应的对策制定至关重要。集约度变化和用途转移构成土地利用变化的两种基本类型,以新古典的边际分析为工具,土地经济学的集约度理论和地租理论所构成的体系解释了在经济活动中土地利用的状态均衡及其变化

Different Shapes of Impeller Affecting on Numerical Flow Field inside Submersible Centrifugal Pump

对具有不同形状叶轮的潜油离心泵进行数值流场分析和研究,在PrO/E中建立三维几何模型,将模型转入gAMbIT进行网格划分,再利用fluEnT软件模拟2种不同形状离心泵叶轮的三维流动。结果显示出离心泵内的压力场、速度场和湍流强度等情况,对比了不同形状叶轮对潜油离心泵内数值流场的影响,为其设计选型及改良提供了可靠依据。This paper focuses on the analysis and research of the submersible pump's numerical flow field which have different shapes of impeller,the submersible pump of the three-dimensional geometric models were build by using Pro/E,dividing into GAMBIT for mesh,re-using Fluent software simulation of two different three-dimensional shape of centrifugal pump flow.The results show that the pressure field inside the centrifugal pump,velocity and turbulence intensity and so on.Compared in different shapes submersible centrifugal pump impeller of the numerical flow field,it provide a reliable basis for selection of improvement.福建省重大科技项目(2010N0202