Results 81 to 90 of about 3,747 (151)

Study on the Preparation of Ion-exchange Coatings for Stir Bar Sorptive Extraction Based on Monoliths and Its Extraction Performance [PDF]

open access: yes, 2011
传统离子样品前处理技术主要为固相萃取(solid-phaseextraction,SPE)和膜萃取(membraneextraction,ME),这两种方法存在操作繁琐、萃取效率低和成本高等不足。搅拌棒固相萃取(stirbarsorptiveextraction,SBSE)是在固相微萃取(solid-phasemicroextraction,SPME)基础上发展起来的一种集萃取、富集、净化为一体的新型样品前处理技术。与传统的样品前处理方法相比,SBSE技术具有操作简便、有机溶剂使用量少 ...
林建斌
core  

Establishment of Ion Chromatography Method for Identification and Determination of the Radiochemical Purity of [11C]Choline Injection [PDF]

open access: yes
[11C]choline is a normal tracer using for PET/CT,identification of [11C]choline and analysis its radiochemical purity are important to guarantee the validity and safety of tracer.
Guojin ZHANG, Shanzhen HE
core   +1 more source

酥朽复合绝缘子轴向老化特性研究

open access: yesDianci bileiqi
复合绝缘子酥朽断裂问题已经成为了阻碍其在电网进一步大范围使用的安全隐患。为了深入地研究酥朽复合绝缘子的劣化特征,通过对现场收集酥朽故障绝缘子试样的宏观分析、解剖分析、电镜扫描分析、傅里叶红外光谱分析、X射线光电子能谱分析等研究了酥朽复合绝缘子轴向老化特性。研究结果表明:酥朽断裂复合绝缘子在轴向上出现明显的区域差异性,断裂面离芯棒断口近的地方芯棒颜色为黑色、白色,离断口远的地方为深棕色、浅棕色,断裂面的反面也出现了相似的趋势,但是受损较轻;黑色区域树脂几乎完全降解,芯棒被严重破坏;白色物质是劣化后的硅橡胶;
刘泽辉   +5 more
doaj  

广州地区输电线路绝缘子污秽成分分析

open access: yesGaoya dianqi, 2013
笔者采用X-射线粉末衍射仪、X-射线能谱仪、电感耦合等离子体发射光谱仪及离子色谱仪对广州市区及郊区化工厂、焦化厂、发电厂、钢铁厂、农田等5种典型环境中的输电线路绝缘子污秽的化学成分进行了定性和定量分析。这些区域绝缘子污秽主要由C、SiO2、CaSO4、硅铝酸盐、氯化物(KCl、NaCl、MgCl2等)、Fe3O4等组成。污秽中的炭黑的存在提高了污秽的电导率,对污闪事故的贡献不容忽视。化工厂和焦化厂附近绝缘子污秽一价盐质量分数较高,有较大的污闪风险,钢铁厂和发电厂绝缘子污秽一价盐质量分数很低 ...
黄青丹   +5 more
doaj  

Determination of Ammonium in Seawater by Two-Dimensional Ion Chromatography [PDF]

open access: yes, 2014
研究了二维离子色谱测定海水中铵离子的方法。海水样品经10倍稀释,一维色谱采用高容量的CS–165 MM柱,以30 MMOl/l甲磺酸溶液等度淋洗,流量为1 M l/MIn,进样25μl,CSrS–300 4 MM抑制电导分离nA+,nH4+;二维色谱采用CS–12A 4 MM柱,以8 MMOl/l甲磺酸溶液等度淋洗,流量为1 M l/MIn,以1 300μl定量环进样,SC–CSrS–300盐转换器抑制电导检测nH4+。结果表明:色谱峰面积与nH4+质量浓度线性相关,相关系数为0.999 9。10μg ...
包洋鸣, 林奇, 林红梅
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Optimization of degrease process during extracting collagen from sea-fish scales [PDF]

open access: yes, 2011
研究了鱼鳞胶原蛋白提取过程中的脱脂工艺条件。采用l9(33)正交实验,考察了碱浓度、温度、时间等因素对鱼鳞脱脂工艺的影响,并使用离子色谱检测了脱脂溶液中羟脯氨酸的含量,以考察各种条件对鱼鳞胶原蛋白在脱脂工艺过程中溶出的影响。确定了鱼鳞胶原蛋白提取过程中的脱脂优化工艺,即温度18℃,碱浓度0.5MOl/l,时间8H。放大实验至原料2kg,得脱脂率为92%,适合规模化生产。Degreasation process during collagen extraction from sea-fish scales
何建林   +6 more
core  

Detection of Intracellular and Extracellular Deoxynivalenol and 15-Acetyl Deoxynivalenol of Fusarium graminearum by GC-MS [PDF]

open access: yes
Fusarium graminearum is the main pathogenic fungus causing wheat head blight. It not only causes severe crop yield reduction, but also produces fungal toxins such as deoxynivalenol (DON) and 15-acetyl deoxynivalenol (15-ADON), which are dangerous food ...
Han-ru GONG   +6 more
core   +1 more source

蛋黄胆固醇的分离及结构鉴定Isolation and structural identification of cholesterol from egg yolk

open access: yesZhongguo youzhi
为探索快速、操作简单的鸡蛋黄中胆固醇的提取分离工艺,采用二元有机溶剂乙醇-正己烷混合溶剂萃取蛋黄中的油脂,以胆固醇含量为指标,通过单因素实验对蛋黄油萃取工艺条件进行优化,利用硅胶色谱柱对蛋黄油中胆固醇进行分离纯化,并通过核磁共振(NMR)进行结构鉴定。结果表明:蛋黄油最佳萃取工艺条件为乙醇与正己烷体积比1∶ 1、液料比3∶ 1,在此条件下胆固醇含量为21.14 mg/g,萃取率达100%;蛋黄油经硅胶色谱柱梯度洗脱后可获得单一组分,经核磁共振氢谱(1H NMR)和碳谱(13C NMR ...
吾惠婷,许先敏,王钰翎,贾文敬,郑永标,黄建忠,舒正玉 WU Huiting, XU Xianmin, WANG Yuling, JIA Wenjing, ZHENG Yongbiao, HUANG Jianzhong, SHU Zhengyu
doaj   +1 more source

Analysis of volatile component in Daqu used for brewing Fuyu flavor Baijiu from different production months based on HS⁃SPME⁃GC⁃MS [PDF]

open access: yes
ObjectiveTo investigate the types and content differences of volatile flavor compounds in Daqu, used for the production of Fuyu flavor Baijiu, from different production months.MethodsHeadspace solid-phase microextraction-gas chromatography-mass ...
CHEN Cai   +4 more
core   +1 more source

超高效液相色谱-串联质谱法快速测定水中19种全氟和多氟化合物

open access: yesJingshui jishu
【目的】本文建立了一种超高效液相色谱-串联质谱法(UPLC-MS/MS),用于快速测定生活饮用水和水源水中19种全氟和多氟化合物(PFASs)。【方法】试验采用UPLC-MS/MS技术,对水样进行快速直接分析。前处理方法极为简单,仅采用0.22μm再生纤维针式过滤器过滤,省略了传统固相萃取的活化、上样、淋洗和洗脱等繁琐步骤,大幅节约了有机溶剂与样品处理时间。目标物经C 18 色谱柱分离后在电喷雾离子源(ESI)负离子模式下电离,采用多反应监测模式(MRM)进行定性和定量分析检测 ...
REN Yuanyuan   +4 more
doaj   +1 more source

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