69 research outputs found
Study and Application of Analytical Method for Pesticide Residues in Tobacco, Vegetables and Fruits by GC-EI/MS
化学农药在防治农作物病虫害的同时也给人类与环境带来了负面影响,食品的质量 与安全是决定人类生存质量的重要因素之一。农药残留问题是目前影响食品安全的首要 问题,一直被世界各国政府和组织所关注,随着世界各国对食品中农药残留种类的要求 越来越多、最高农药残留限量标准的要求越来越低,研究与建立行之有效的农药残留分 析方法,以保证食品的质量与安全和促进农产品的出口贸易十分必要。 本学位论文致力于食品中有机氯类、有机磷类和拟除虫菊酯类农药的农药残留分析 方法研究,优化了气相色谱-电子轰击电离源/质谱联用法(GC-EI/MS)的分析条件,探讨 了水果保鲜剂中农药组分对水果中农药残留的影响,初步...Pesticide is a double-edged sword, it protects agriculture products from destroyed by plant diseases and insect pests and provides benefits in increasing crop production while it has a negative impact or even a threat to human and environment as well. The quality and safety of food is crucial to human’s life while the pesticide residue is one of the most important problems which attract much att...学位:理学硕士院系专业:化学化工学院化学系_分析化学学号:2052006115192
Study on the phonology of DengYun JingYao
《等韵精要》一书镌于乾隆乙未年(1775年),作者贾存仁,山西浮山人。一些音韵学者都曾研究过《等韵精要》:耿振生先生认为它的音系属于官话方言一系;李新魁先生在《汉语等韵学》中评价它是一部反映语音骨架的等韵图,能够清楚的看出当时共同口语的语音面貌;宋珉映先生认为《等》属于近代北方话音系。本文从声韵调三个方面来系统地研究《等》的音系特点,并对《等》中独特语音现象进行分析,从而给本书性质一个新的定位。本文共分六章: 第一章绪论,主要介绍作者贾存仁、《等韵精要》的例体及成书目的; 第二章从七个方面来介绍贾存仁的音理观; 第三章主要讨论《等韵精要》的声母系统,并就其中“全浊声母清化、精见组是否颚化...“DengYun JingYao”, a rhythmic book in Qianlong decade of Qing Dynasty written by Jia Cunren. His hometown is Fushan, Shanxi province. Some scholars studied this book: Geng Zhensheng regareded it standed for a dialect of Mandarin. Li Xinkui regarded it reflected the spoken pronunciation of that time in his “Study on Chinese Dengyun Chart”. Song Minying regarded it belonged to the Modern pronunciati...学位:文学硕士院系专业:人文学院中文系_汉语言文字学学号:20040102
Surface Modification of Nano-scale Titanium Dioxide and the Efftect of Photocatalytical Sterilization
摘要纳米TiO2粉体的合成及其应用是新材料研究的热点之一,其独特的光催化作用、颜色效应以及紫外屏蔽等功能使其在汽车工业、防晒化妆品、涂料﹑橡胶、化纤、废水处理、杀菌、文物保护、环保等方面有着广阔的应用前景。同时,由于纳米TiO2具有强极性,使得TiO2不易在非极性介质中分散,在极性介质中易于团聚,直接影响二氧化钛本身优异性能的发挥。因此,需对其进行表面改性处理,以便在非极性介质或极性介质中获得良好的分散性。本论文的工作是用廉价易得的原料合成纳米TiO2,并对纳米TiO2进行亲油和亲水改性,利用SEM、TEM、XRD、EDS等手段对其组成、结构、尺寸和形貌进行表征,对其实际应用进行初步探讨。主要...Abstract The synthesis and application of nano-scale TiO2 attract the interest of researcher in material field. And the nano- scale TiO2 can be used widely in many fields such as photocatalyst,sterilization,environment et al. Because ultrafine TiO2 is strong polarity material, the nano-scale TiO2 cann’t be dispersed in non-polarity solvent well and tend to agglomerate in the polarity so...学位:理学硕士院系专业:化学化工学院化学系_有机化学学号:20022504
Research on Some Issues of Bribery Investigation——Evidence Focused
内容摘要 当前,贪污贿赂犯罪继续呈现高发态势,而贿赂犯罪成为腐败犯罪主要表现。贿赂犯罪本身具有隐蔽性强、智能化程度高等特点,行贿人与受贿人往往“一对一”完成犯罪,贿赂犯罪发现难、取证难、鉴证难和处理难。为了有效应对贿赂等腐败犯罪,许多国家和国际组织设立了专门反腐败机构,制定了严密的侦查措施和配套制度,以破解贿赂犯罪发现难、取证难、鉴证难和处理难。此外,证据规则的有效设计在贿赂犯罪的侦查中也至关重要。本文从取证主体、取证措施及证据规则等对贿赂犯罪侦查中的相关问题进行了研究,对我国贿赂侦查的现状进行了总结与反思,并借鉴外国先进的立法经验,结合具体的工作实际,提出了相应改革建议。 本文共分五...Abstract At present, more and more incidents of corruption and bribery crimes occur, and bribery crime has become the main manifestation of corruption crimes. Bribery crime has the characteristics of high concealment, high intellectualization and so on. It is often carried out in a “one to one” way between the briber and the bribe. So it is hard to find, hard to get the evidence, hard to disc...学位:法学硕士院系专业:法学院法律系_法律硕士(JM)学号:X201012006
Research on the cross-layer design of underwater acoustic networks
跨层设计是水声网络中急需解决的关键技术之一。对于能量和可用频带严重受限的水声网络系统,跨层设计能有效地利用海洋声信道环境下稀少的可用资源,克服分层网络设计中非最优和不灵活的缺点,使系统运行在最佳模式下。在介绍国内外水声网络跨层设计研究的基础上,提出了一种基于控制通道和数据通道的双通道水声网络跨层设计模型,分析了该跨层网络模型的优势,并给出一种自适应节点调制和编码的双通道水声网络跨层模型应用方案,在水池和厦门海域中进行了多节点自组织组网实验,验证了该方案的可行性,表明双通道跨层模型在水声网络设计中具有良好的应用前景。Cross-layer design is one of the most significant and urgently needed techniques for Underwater Acoustic Networks(UWANs).For the energy and bandwidth severely limited UWANs system,cross-layer design can effectively utilize the scarce resources in such special environment as underwater acoustic channels,overcome the disadvantages of the non-optimum and the inflexibility of the traditional layering network design,and optimize the functionality of the system.In this paper,we introduce recent advances in the cross-layer design of UWANs,propose a kind of dual-channel(a control channel and a data channel) cross-layer design for UWANs and analyze the advantages of our dual-channel cross-layer model.Based on the dual-channel cross-layer model,the paper provides an adaptive modulation and coding with practical applications.Some multiple-node self-organized networking experiments are conducted in the water pool and Xiamen waters.Promising experimental results are obtained and show that dual-channel cross-layer model could offer diverse applications in underwater acoustic networks in the future.国家自然科学基金(41176032);厦门大学研究生基础创新科研基金(201212G012
基于“三生”适宜性的旅游度假区潜在土地利用冲突识别与治理
社会经济的快速发展与人们旅游需求的转变引导度假区成为旅游产业转型升级的重要场所,而学术界对此过程中出现的土地利用冲突问题却缺少必要的学术跟进。该文基于可持续发展广泛认可的"生态-生产-生活"视角,解析了旅游度假区土地利用生态、生产与生活适宜性的内涵,构建了旅游度假区生态、生产与生活适宜性评价模型及潜在土地利用冲突识别与强度诊断经验模型,并选取武夷山国家旅游度假区进行实证分析。理论上,将潜在土地利用冲突类型区划分为无冲突区、轻度冲突区、中度冲突区、强烈冲突区、剧烈冲突区,并将冲突的控制级别分为稳定可控、基本可控、基本失控和严重失控4个层次。实证表明,武夷山国家旅游度假区生态、生产与生活适宜性用地的空间集聚特征与面积构成差异显著,暗示着区域土地利用存在着竞争与冲突。从潜在冲突识别的结果来看,不同类型冲突区的面积占比依次为17.76%、35.59%、22.37%、23.74%、0.55%。旅游度假区潜在土地利用冲突区的空间分布、表现形式及冲突程度的差异性决定了冲突治理策略也应有所区别,如可以因地制宜地采取空间管制、品质提升、功能显化等策略
Species composition and seasonal variation of marine nematodes on Futian mudflat in Shenzhen estuary
1997年 4个季度在深圳河口福田泥滩 3个取样站采到海洋线虫 2 8种 ,隶属于 3目 1 3科 2 2属。优势种是微口线虫 (Terschellingiasp1 .)、吞咽线虫 (Daptonemasp1 .)、Metalinhomoeussp .和拟齿线虫 (Paradontophorasp .) 4种。春季海洋线虫密度最高 ,冬季次之 ,夏季第三 ,秋季最低。深圳河口福田泥滩的海洋线虫群落与大型底栖动物群落具有相似的特点 ,即种类少 ,种类多样性指数和丰度指数低 ,但优势种呈现出较高的种群密度。深圳河口福田泥滩海洋线虫和多毛类独毛虫的数量消长有相似之处 ,即冬季和春季密度高 ,而夏季和秋季密度低 ,这种现象与它们共同的生态习性有关 ,因为它们都能在高有机质含量区域大量繁殖。We set up three sampling stations on the mudflat in Shenzhen estuary to investigate free_living marine nematodes. Twenty_eight species of marine nematodes were obtained during four surveys. These nematodes belong to 22 genera, 13 families and three orders. The dominant species were Terschellingia sp1., Daptonema sp1., Metalinhomoeus sp. and Paradontophora sp. The density of marine nematodes was the highest in spring, the second in winter, the third in summer and the lowest in autumn. The pattern of marine nematode assemblage was similar to that of the macrofaunal community on the mudflat in Shenzhen estuary. For example, both had low species number, low species diversity index and low richness index, and the dominant species appeared with high population density. The seasonal fluctuation of the nematode abundance showed almost the same pattern as the abundance of the polychaete, Tharyx sp. It appeared that the most dominant species of nematodes had a type of symbiotic relationship with Tharyx sp. This phenomenon may relate to their ecological habit because they live and breed in mudflats with high content of organic matter
一种水声网络全双工通信方案研究
提出一种利用水声网络的路由控制节点协作传输,运用多用户物理层与“双向分流“修正的路由相结合,将单一节点的半双工提升为网络支路的全双工通信,并利用nIC-rIO和lAbVIEW搭建了四个节点组成实验网络,在水池中验证了其可行性,在水声网络领域有一定的意义和应用前景
Determination of 29 pesticide residues in tobacco by gas chromatography-electron impact ionization mass spectrometry
开展了卷烟和烟叶中有机氯、有机磷和拟除虫菊酯3类29种农药残留的气相色谱-电子轰击离子源质谱(gC-EI/MS)的分析方法研究。优化与选择了卷烟和烟叶样品的前处理条件,样品经正己烷-丙酮(体积比为1∶1)混合提取剂超声提取、flOrISIl硅土和中性氧化铝双净化剂固相萃取柱净化、二氯甲烷-正己烷(体积比为95∶5)混合洗脱剂洗脱和浓缩后,以磷酸三苯酯(TPP)为内标物,采用gC-EI/MS的选择离子监测方式(SIM)进行定性和定量分析。当样品的加标水平为20,50,100μg/kg时,加标回收率为70%--110%,相对标准偏差在2%--8%之间;除了甲氰菊酯、氯菊酯和溴氰菊酯的方法检出限(lOd)分别为1.85,1.74与2.54μg/kg外,其余的26种农药的lOd均小于0.8μg/kg;线性范围为5.0--500.0μg/kg,相关系数都大于等于0.999 4。此分析方法已成功地应用于卷烟和烟叶样品中3类29种痕量农药残留的分析。A method was developed for rapid determination of 29 pesticide residues in tobacco based on gas chromatography coupled with electron impact ionization mass spectrometric detection(GC-EI/MS).After the optimization of different parameters,such as the extraction solvent,elution solvent,purificant,pesticides were extracted from tobacco with hexane-acetone(1∶1,v/v) in an ultrasonic bath,cleaned-up on a column,packed with Florisil and neutral alumina,eluted with dichloromethane-hexane(95∶5,v/v),and then determined by GC-EI/MS in the selected ion monitoring mode(SIM) with triphenyl phosphate(TPP) as internal standard.The recoveries were performed at 20,50 and 100 μg/kg fortification levels for each pesticide,and the recoveries ranged from 70% to 110% with the relative standard deviations between 2% and 8%.The detection limits were less than 0.8 μg/kg for 26 pesticides except for the fenpropathrin,deltamethrin and permethrin.The method was linear over the range of 5.0-500.0 μg/kg with the correlation coefficients between 0.9994 to 0.9999.The method was successfully applied to the analysis of these pesticides in tobacco.国家基础科学人才培养基金项目(J0630429
基于LabVIEW的海洋声学仪器信号识别方法
在总结几种常用海洋声学仪器的基本原理以及信号特征基础上,提出了采用频谱分析和自相关方法提取噪声中的信号频率、脉宽、周期信息,采用短时傅里叶变换提取海洋声学仪器信号的时-频特征值的方法,并与相关的海洋声学仪器信号参数数据库比对,设计了信号识别方法。基于lAbVIEW软件构建了一套几种常用海洋声学仪器的信号识别系统,给出了识别系统的软件操作界面。通过应用实测AdCP数据和仿真信号源所产生的几种声学仪器信号进行信号识别检验,表明该系统能够在较低的信噪比条件下准确的识别已知特征参量的海洋声学仪器信号。研究成果可用于检测海洋中声学仪器的工作状态,识别不同海洋声学仪器。科技部科技创新项目资助;福建省科技重点项目(NO:2009N0050
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