21 research outputs found

    Accelerate the development of modern logistics industry in China

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    20世纪80年代以来,经济全球化的持续发展,科学技术水平的不断提高以及社会专业化分工进一步深化,一些发达国家开始了一场物流革命,从而促进了本国国民经济的发展。中国物流业起步较晚,但进入2l世纪以来,国内物流业持续升温,发展势头相当迅猛,物流作为提高市场竞争力的关键因素和影响众多领域发展的巨大潜在市场,开始受到中央、地方、乃至企业的广泛关注,人们越来越认识到,物流产业的发展是促进经济发展和经济增长的“加速器”。而本文通过分析我国物流研究的状况,剖析国内物流业存在的问题,归纳总结了国外可供借鉴的经验启示,提出了近期发展国内物流业的对策,希望对加快我国现代物流业的发展、优化资源配置、提高经济运行质量...Since 1980’s, with the sustainable development of economic globalization, continuous improvement of science and technology, as well as the further deepening of social specialization, some of the developed countries have started a logistics revolution, thereby contributing to their development of the national economy. Although China's logistics industry started a little bit late, the domestic logis...学位:经济学硕士院系专业:经济学院经济系_西方经济学学号:X200514101

    Multiresidue Determination of Organophosphorus Pesticide Residues in Vegetables and Fruit by Gas Chromatography-Negative Ion Chemical Ionization-Mass Spectrometry

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    将气相色谱-负离子化学电离质谱法(GC-NC I-M S)应用于蔬菜水果中9种有机磷农药残留的分析测定,初步解析了这些农药的NC I-M S特征阴离子结构和断裂机理,并初步探讨了GC-NC I-M S分析蔬菜水果中有机磷农药残留时基体效应的影响。采用空白样品基体匹配校准曲线法(M C)进行定量分析,有效地降低了基体效应的影响。蔬菜水果样品用乙酸乙酯超声提取,以乙硫磷为内标物,采用GC-NC I-M S的选择离子监测方式(S IM)进行定性和定量分析。9种有机磷农药的方法检测限为0.12~1.0μg/kg。在方法的检测限与1 000μg/kg范围内,线性相关系数都大于0.999 3。当空白蔬菜水果(西红柿)样品的加标水平为100,400,800μg/kg时,平均加标回收率为78%~126%,相对标准偏差为0.58%~14.7%。An analytical method of gas chromatography coupled with negative ion chemical ionization-mass spectrometry for simultaneous determination of nine organophosphorus pesticide residues in vegetables and fruit has been developed,and the negative ions structure and partition mechanism of the nine organophosphorus pesticides were interpreted.Meanwhile,the matrix effect for sample analysis was discussed,and matrix-matched calibration for quantification was introduced to reduce the matrix effect in this method.Pesticides were extracted from sample with ethyl acetate in an ultrasonic bath,then determined by gas chromatography-mass spectrometry operated in negative chemical ionization mode and quantified in selective ion monitoring mode,and ethion was used as an internal standard.The detection limits of the method were 0.12-1.0 μg/kg for the nine organophosphorus pesticides,and the relative coefficients were higher than(0.9993).A blank sample(tomato) was spiked at 100,400,800 μg/kg for each pesticide,and the recoveries were determined to be from 78% to 126% with relative standard deviations from 0.58% to 14.7% for the pesticides

    Determination of Multiple Pesticide Residues in Honey Using Gas Chromatography-Mass Spectrometry

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    开展了蜂蜜中23种农药残留的气相色谱-电子轰击离子源质谱(GC-E I/M S)分析方法的研究,并对其中3种农药的E I/M S碎片离子的断裂机理与结构进行了初步解析。探讨了蜂蜜试样前处理条件的优化与选择。将蜂蜜试样用乙酸乙酯提取剂超声提取、F lo ris il硅藻土色谱柱净化和正己烷-乙酸乙酯(体积比为7∶3)混合洗脱剂洗脱后,以PCB103为内标物,采用选择离子监测(S IM)方式下的GC-E I/M S分析。当试样的加标浓度为50,100和200μg/kg时,加标回收率为82%~120%,相对标准偏差小于11.0%。23种农药的检测限都小于10.0μg/kg,线性范围为10~500μg/kg,相关系数都大于0.995。此分析方法已成功地应用于蜂蜜中23种痕量农药残留的分析。An analytical method was developed for the simultaneous determination of 23 pesticide residues in various commercial honeys.Meanwhile,the characteristic ions and fragmentation mechanism of three pesticides in the process of electron ionization mass spectrometry(EI/MS) were evaluated.After the optimization of different parameters such as the extraction solvent,pesticides were extracted from honey with ethyl acetate in an ultrasonic bath,cleaned up on a Florisil column by an elution of mixture of hexane and ethyl acetate(7∶ 3,v/v), and analyzed by gas chromatography-electron ionization mass spectrometry(GCEI/MS) in the selected ion monitoring mode(SIM) with PCB103 as internal standard.Recovery studies were performed at 50,100 and 200 μg/kg fortification levels for each pesticide,and the recoveries ranged from 82% to 120% with relative standard deviations between 1.8% and 11.0% for different pesticides.The limit of detection was less than 10.0 μg/kg for all the pesticides.The developed method was linear in the range of 10-500 μg/kg,with correlation coefficients larger than 0.995.Finally,the developed analytical method has been successfully applied to the determination of pesticide residues in several honey samples

    Determination of 19 Organophosphorous Pesticides Residues in Milk Drink and Milk Powder by Gas Chromatography-Negative Chemical Ionization-Mass Spectrometry

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    将气相色谱-负离子化学源质谱法(GC-NCIMS)应用于牛奶饮品和奶粉中19种有机磷农药残留的同时分析。牛奶饮品和奶粉经乙腈提取剂超声提取、Florisil硅藻土和中性氧化铝双净化剂同时净化及正己烷-乙酸乙酯(体积比1∶1)混合洗脱剂洗脱后,以三苯基磷酸酯为内标物,采用GC-NCI MS的选择离子监测方式(SIM)定性与定量分析。当牛奶饮品和奶粉的加标浓度水平为20、100、500μg/kg时,平均加标回收率为64.5%~129%,相对标准偏差为2%~20%;除喹硫磷的方法检出限(MDL)为2.4μg/kg外,其余18种有机磷农药的MDL均小于1.0μg/kg;线性范围为10~500μg/kg,相关系数均大于0.9988,此分析方法成功地应用于牛奶饮品和奶粉中多种痕量有机磷农药残留的分析。A rapid method was developed for the determination of 19 organophosphorous pesticides residues in commercial milk drink and milk powder.Under optimized conditions,the pesticides were extracted from milk drink or milk powder with acetonitrile in an ultrasonic bath and cleaned up on a Florisil and neutral alumina column,and were determined by gas chromatography with negative chemical ionization mass spectrometric detection in the selected ion monitoring mode with triphenyl phosphate as internal standard.The recoveries for all the pesticides studied ranged from 64.5% to 129% with a relative standard deviation range of 2%-20%.The detection limit of the method was less than 1.0 μg/kg for most of the pesticides except for the quinolphos.The linear ranges of the calibration curves ranged from 10 μg/kg to 500 μg/kg with correlation coefficients of 0.998 8.The proposed method was successfully applied to the analysis of these compounds in milk drink and milk powder

    Simultaneous determination of 14 phthalate ester residues in animal innards by gas chromatography-mass spectrometry with electron impact ionization

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    开展了动物内脏中14种酞酸酯类(PAEs)环境激素残留的气相色谱-电子轰击离子源质谱(GC-EI/MS)分析方法的研究,优化与选择了动物内脏样品的前处理条件。动物内脏样品经正己烷-二氯甲烷(体积比为1∶1)混合提取剂超声提取、Florisil硅土固相萃取柱净化与乙酸乙酯-正己烷(体积比为2∶3)混合洗脱剂洗脱和浓缩后,以邻苯二甲酸二苯基酯(DPhP)为内标物,采用GC-EI/MS的选择离子检测方式(SIM)进行定性和定量分析。当猪肝样品的加标浓度水平为100,200,400μg/kg时,加标回收率为60%~110%,相对标准偏差为0.8%~10.3%。除邻苯二甲酸二甲氧基乙酯(DMEP)与邻苯二甲酸二(2-乙氧基乙基)酯(DEEP)的方法检出限(MDL)分别为3.30μg/kg与2.25μg/kg外,其余12种PAEs的MDL均不大于1.74μg/kg;线性范围为50.0~800.0μg/kg,相关系数均大于0.9994。该分析方法已成功地应用于6种动物内脏中14种痕量PAEs残留的分析。An analytical multiresidue method was developed for the simultaneous determination of 14 phthalate esters (PAEs) in animal innards by gas chromatography-mass spectrometry with electron impact ionization (GC-EI/MS). After the optimization of different parameters such as the extraction solvent, PAEs were extracted from animal innards with hexane-dichloromethane (1∶1, v/v) in an ultrasonic bath and cleaned up on a Florisil column, then were determined by GC-EI/MS in selected ion monitoring mode with diphenyl phthalate (DPhP) as internal standard. The recovery studies were performed at 100, 200 and 400 μg/kg levels for each PAE, and the recoveries ranged from 60%-110% with the relative standard deviations between 0.8% and 10.3% for different PAEs. The detection limit of the method was less than 1.74 μg/kg for most of PAEs except dimethoxyethyl phthalate (DMEP) and di(2-ethoxyethyl) phthalate (DEEP). The method was linear over the range of 50.0-800.0 μg/kg with the correlation coefficients larger than 0.999 4. The method has been successfully applied to the determination of 14 PAEs in six animal innards.国家基础科学人才培养基金(J0630429)项目资

    Determination of Five Polybrominated Diphenyl Ether Residues in Deep-Sea Fish Oil Using Gas Chromatography-Negative Chemical Ionization/Mass Spectrometry

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    建立了气相色谱-负离子化学电离质谱法(GC-NCI/MS)同时分析深海鱼油食品中5种多溴联苯醚残留的分析方法。深海鱼油食品用正己烷超声提取、中性与酸性硅胶色谱柱净化和正己烷洗脱后,以PCB103为内标物,采用GC-NCI/MS的选择离子监测方式(SIM)分析;同时探讨了5种多溴联苯醚的NCI/MS特征离子的断裂机理。当空白深海鱼油食品的加标浓度为20.0和100.0μg/kg时,加标回收率为88.6%-111.3%,相对标准偏差为3.8%-13.5%,方法的检测限为0.77-1.34μg/kg,线性范围为1.0-500.0μg/kg,相关系数均大于0.999 2。此方法已成功地应用于深海鱼油食品中5种痕量多溴联苯醚残留的同时分析。Polybrominated diphenyl ethers(PBDEs) are a kind of brominated flame retardants(BFRs),which refer to compounds used in some plastics to impede or even suppress the combustion process.As the emission or disposal of plastics,PBDE residues have been found in both environment and biota.In this work,an analytical method was developed for the simultaneous determination of 5 PBDE residues in deep-sea fish oil.PBDEs were extracted from deep-sea fish oil with n-hexane,cleaned up on a silical gel column,and determined by using gas chromatography-negative chemical ionization/mass spectrometry(GC-NCI/MS) in the selected ion-monitoring(SIM) mode,with PCB103 as the internal standard.Meanwhile,the characteristic ion and fragmentation mechanism of some PBDEs in NCI/MS were evaluated.Recovery studies were performed at 20.0 and 100.0 μg/kg fortification levels for each PBDE,and the recoveries ranged from 88.6% to 111.3% with relative standard deviations between 3.8% and 13.5% for different PBDEs.The limits of detection(LOD) were from 0.77 to 1.34 μg/kg for different PBDEs.The developed method was linear over the range assayed,1.0-500.0 μg/kg,with correlation coefficients larger than 0.999 2.The developed method has also been successfully applied to the determination of PBDEs in several deep-sea fish oil samples and the three most abundant PBDEs(PBDE-47,PBDE-99 and PBDE-100) were found

    应用于同步加速器时序控制的片上可编程系统的设计

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    同步加速器对控制信号的时间约束要求非常严格,时序控制是加速器控制系统中十分重要的环节。在兰州重离子加速器冷却储存环(HIRFL-CSR)控制系统中,时序控制主要采用FPGA+ARM+linux+DSP的体系结构。本文介绍基于FPGA和uClinux操作系统的片上可编程系统(SOPC)的设计,可将目前ARM+LINUX的工作完全集成在FPGA内实现,省去专用ARM芯片。其最高工作频率可达185 MHz,硬件资源消耗不到4%。片上可编程系统的硬件处理器系统和操作系统都可根据具体需求重新裁剪和配置。SOPC技术在加速器物理以及其他领域有着非常广泛的应用前景

    Multiresidue Determination of 17 Organochlorine and Pyrethroid Pesticides in Tea by Gas Chromatography-Negative Chemical Ionization-Mass Spectrometry

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    建立了茶叶试样中17种农药残留(8种有机氯和9种拟除虫菊酯农药)的气相色谱-负化学离子源-质谱(GC-NC I-MS)联用的分析方法.茶叶试样用V(正己烷)/V(丙酮)=1/1混合提取剂超声提取,经F lorisil硅藻土和中性氧化铝混合层析柱净化后,以环氧七氯为内标物,采用GC-NC I-MS的选择离子监测方式(SIM)分析;探讨了茶叶试样的基体诱导色谱响应增强影响所产生的分析误差及其减小的措施,用空白试样基体匹配校准曲线法(MC法)定量分析.当加标质量浓度水平为20,50和200μg/kg时,加标回收率为67.9%~129%,相对标准偏差为1.0%~20%,除氯菊酯农药的检出限为8.3μg/kg外,其余大部分农药的检出限均小于1.0μg/kg,线性范围为10~500μg/kg,相关系数均大于0.996,此方法成功地应用于茶叶试样中痕量农药残留的分析.An analytical multiresidue method for the simultaneous determination of 17 pesticides(8 organochlorines and 9 pyrethroids) in tea was developed.Pesticides were extracted from tea with hexane-acetone(volume ratio is 1∶1) in an ultrasonic bath and cleaned up on a Florisil and neutral alumina column, then were determined by gas chromatography with negative chemical ionization mass spectrometric detection in the selected ion monitoring mode,and with heptachlor epoxide as the internal standard.Spiked blank samples were used as standards to counteract the matrix effect observed in the chromatographic determination.The recovery studies were performed at 20,50 and 200 μg/kg fortification levels for each pesticide,and the recoveries ranged from 67.9% to 129% with a relative standard deviation between 1.0% and 20% for the different pesticides. The detection limit of the method was less than 1.0 μg/kg for most of pesticides except for the permethrin.The developed method was linear over the range assayed,10-500 μg/L,with determination coefficients>0.996.Finally,the developed analytical method was successfully applied to the determination of pesticides in several tea samples

    Design of Ion-pump Power Supply Control Software System Based on TCP/IP Protocol

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    This paper discuss a Ion-pump Power Supply control system making use of RS232 series bus and Intranet.The system s hardware VAC800 is composed of MSP430F149 mixed-signal processors produced by TI and UA7000A network model.MSP430F149 has advantages of ultra-low-power and high-integration.The Ion-pump Power Supply control system has the characteristics of strong function,simple structure,high reliability,strong resistance of noise,no peripheral chip,etc.Visual studio 2005 is used to design the system s softwa...中文文摘:论述了通过RS-232总线和Intranet网络,来实现对远端的离子泵电源的监测与控制。系统硬件VAC800由TI公司的MSP430F149混合信号处理器和UA7000A网络模块构成。MSP430F149具有超低功耗和高集成度等优点,利用它构建的离子泵电源监控系统功能强大,结构简单,可靠性高,抗干扰能力强。系统软件采用visual studio 2005设计。本监控系统能够很好地完成对加速器离子泵电源监视与控制

    Multiresidue determination of organochlorine pesticides in honey by gas chromatography-mass spectrometry

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    建立了气相色谱-电子轰击离子化-质谱法(GC-EI-MS)同时分析蜂蜜试样中12种有机氯农药残留的分析方法。蜂蜜试样用V(正己烷)∶V(乙酸乙酯)=5∶1混合提取剂超声提取和Florisil硅藻土层析柱净化后,以PCB 103为内标物,采用GC-EI-MS的选择离子监测方式(SIM)分析,同时探讨了一些有机氯农药EI-MS特征离子的结构与断裂机理。当空白试样的加标浓度为10、50、200μg/kg时,加标回收率为80%~112%,相对标准偏差为0.4%~9.8%,方法检出限为0.2~4.0μg/kg,其中8种农药的MDL0.996.Finally,the developed analytical method has been successfully applied to the determination of pesticides in several honey samples
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