118 research outputs found

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

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    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、富集倍数高和环境友好等优点,近几年被广泛应用于各种样品中有机污染物的分析,但还未涉及对无机离子的吸附研究。因...Traditional sample preparation technologies for inorganic ions include solid phase extraction (SPE) and membrane extraction (ME). Sometimes it is inconvenient for SPE because more steps are involved in the extraction and pre-concentration. Single use and low extractive capacity limit the application of ME. Stir bar sorptive extraction (SBSE) based on solid-phase microextraction (SPME), is a novel ...学位:理学硕士院系专业:海洋与环境学院环境科学与工程系_环境科学学号:2262008115153

    某工程桩基质量问题的一种处理方法

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    据统计,国内灌注桩施工中桩身出现质量缺陷的概率达20%。一旦发生桩基质量事故,应及时进行事故原因分析评判,对事故进行处理,以保证建筑物的正常使用,并尽量减少经济损失。通过对一起桩基事故的分析和处理,说明其处理的方法及其原理,为今后相关处理提供经验借鉴

    全参数全约束优化对钢筋混凝土框架结构设计的造价分析

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    目前的优化设计一般是将参数简化为一维问题或多维问题,或为全参数优化设计,但约束条件不够充分.针对这些不足,本文建立了更全面的符合工程设计的全参数全约束优化设计模型,利用MATLAB中的fmincon函数进行寻优计算,它可以同各种结构设计软件链接进行参数优化,如本文算例采用了中国建筑设计研究院开发的PKPM软件中已有的内力计算功能.最后,通过算例将各参数对造价影响程度进行分析比较,得出了定性及定量的结论,优化后的结构造价降低显著.与当前的钢筋混凝土框架结构优化设计相比,本文具有较强的实用性、寻优计算快捷等优点

    A New Method for the Measurement of Complexation Stability Constant and Average Coordination Number of Metallic Element with Polymer

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    建立了基于化学平衡理论模型以及凝胶过滤色谱(gfC)-电感耦合等离子体质谱(ICPMS)联用技术的高分子聚合物-金属配合物稳定常数、平均配位数测定新方法。以聚乙烯亚胺(PEI)和Cu2+为例,对形成的PEI-Cu配合物稳定常数、平均配位数进行测定,以0.02 MOl·l-1 HAC-nAAC为流动相,凝胶色谱柱分离大分子PEI-Cu配合物以及Cu的小分子配合物、游离态离子,最后用ICPMS测定不同形态金属元素的浓度;利用建立的化学平衡理论模型,计算PEI与金属离子形成配合物的稳定常数、平均配位数,测得25℃,PH4.1~5.3时,PEI-Cu配合物稳定常数为109.6~1010.7,平均配位数为1.0~1.3。建立的在线分离、测定方法具有快速、准确的特点,为高分子聚合物-金属配合物的研究提供新的技术手段。A new method using gel filtration chromatography(GFC) and inductively coupled plasma mass spectrometry(ICPMS) was developed for the measurement of complexation stability constant and average coordination number of the complex of metallic ion with polymer.As an example,the binding of PEI with Cu2+was shown and investigated.The macromolecular PEI-Cu complex and micromolecular species of Cu (Ⅱ) were firstly separated by a low efficiency GFC column with a mobile phase of 0.02 mol·L-1HAc-NaAc buffer,and then directly introduced into ICPMS for elemental analysis.The results of complexation stability constant and average coordination number characterized by putting the concentration of different species of metallic element into the equations of the novel chemical equilibrium model which was developed in this study.The results shown that the complexation stability constants(KPEI-Cu) were between 109.6and 1010.7and the average coordination numbers(n) were in the range of 1.0~1.3 when pH was changed from 4.1 to 5.3 at 25 ℃.This online,rapid and accurate method of GFC-ICPMS is a novel technique for the research of polymer-metallic complex.厦门大学近海海洋环境科学国家重点实验室自主创新项目(MELRI0703)资助项

    Surface-enhanced Raman Spectroscopic Study of Gold Nanoparticles with Different Shapes

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    【中文文摘】使用514 5nm激光激发,第一次得到了不同形状金纳米粒子的表面增强拉曼光谱(SERS)。一般情况下,较短波长(600nm)的激发。然而,对特殊形状的自组装金纳米粒子,由于避雷针效应,即使使用绿光激发也可获得很高增强的SERS。 【英文文摘】In this communication, we obtained for the first time the SERS spectra of gold at the laser excitation of 514.5 nm by fabricating the ordered array of gold nanoparticles with special shapes, e.g., sphere, tadpole, and pearlchain. Selfassemble method of these gold nanoparticles is briefly introduced. In general, the enhancement of gold by the laser excitation of short wavelength (600 nm) becuase that the coupling between conduction electrons and interband electronic transitions by using 514. 5 nm depresses the quality of the surface plasmon resonance of gold metals considerably. Our observation reveals that the SERS of self2assembly gold nanoparticles with special shape can be rather high even using the green light excitation , which is mainly due to the lightning2rod effect.国家自然科学基金创新群体研究资助项目(20021002);; 国家自然科学基金九五重点项目(29833060

    The Size and Shape Effects on the Optical Properties of Gold Nanoparticles

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    【中文文摘】纳米尺度的金属及半导体呈现出特殊的光学、电学及磁学性质,采用近年发展起来的离散偶极近似(DDA)的方法,我们分析了金纳米粒子的尺寸及形状对其光学性质的影响。粒子周围介质的影响在文中亦作了分析。计算结果显示,金纳米粒子的等离子体吸收带同时受到粒子尺寸和形状的影响,但来自形状的影响更为明显。与米氏理论及扩展的甘氏理论相比较,DDA方法在粒子尺寸不再远小于入射光波长的时候更准确,并能应用于任何形状的纳米粒子。理论计算与实验结果能较好的吻合。 【英文文摘】Metals and semiconductors exhibit unusual optical, electronic, and magnetic properties at the nanometer scale. Based on the newly developed method, discrete dipole approximation (DDA), the dependence of the optical properties of the gold nanoparticles on the size and shape was analyzed. The effects of the surrounding medium were also taken into consideration in the calculation. The calculated results show that the plasmon absorption band depends on both the size and shape of the gold noanoparticles. However , the influence of the shape is more significant . Compared to the Mieps theory and the extension , Gansp theory , the DDA method is more accurate when the dimensions of the particles are not much smaller than the wavelength of the incident light and can be applied to particles of any shape. The theoretical results are in good agreement with the experimental data.国家自然科学基金项目,批准号为 :20003008,2983306

    Study on the Distributions of Lead and Cadmium in Rats by ICP-MS with Stable Isotope Tracer

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    采用稳定同位素示踪技术研究重金属元素铅、镉在大鼠体内的分布,通过对大鼠进行浓缩同位素206Pb、112Cd灌喂,解剖取其肝、肾、睾丸和心脏等脏器,通过相应的化学处理,用电感耦合等离子体质谱(ICP-MS)测量铅、镉元素在各个脏器中的含量及其同位素组成变化。根据同位素比值的变化研究Pb、Cd在各脏器中的分布、蓄积规律和各脏器对引入的浓缩同位素利用率。结果发现:重金属Pb和Cd蓄积的最主要场所是肝和肾,其次是睾丸和心脏,而在脑中的积累最少。在肝和肾中Cd的同位素利用率为0.0488%、0.0154%,Pb的同位素利用率为0.0101%、0.0078%,远高于其它脏器。与传统的方法相比较,该法具有更接近慢性中毒、危害性小,能将重金属来源分为天然来源和人为引入等特点。The distributions of lead and cadmium in rats were studied using stable isotope tracer technique.The rats were fed with enriched stable isotope 206Pb and 112Cd,then the liver,kidney,testicle and heart were eviscerated.After chemical treatment,the contents of lead and cadmium and their isotope ratios in each viscera were determined by ICP-MS.Experimental results showed that lead and cadmium accumulated mostly in liver and kidney,next in testicle and heart,and least in brain.The utilization rates of cadmium and lead isotopes in liver were 0.048 8% and 0.010 1%,respectively,and in kidney 0.015 4% and 0.007 8%,respectively.Compared with the traditional methods,the present method can differentiate the origins of lead and cadmium.福建省重大科技项目资助课题(2003Y005-04,2003Y003

    下调基因PTTG1对人胶质瘤细胞SHG44增殖、凋亡、迁移和侵袭能力的影响

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    背景与目的:研究表明垂体瘤转化基因1(pituitary tumor-transforming gene 1,PTTG1)在多种癌症中高表达。该研究旨在探讨其对胶质瘤细胞SHG44增殖、凋亡、迁移和侵袭能力的影响。方法:用PTTG1 siRNA干扰胶质瘤细胞SHG44的基因表达,通过实时荧光定量聚合酶链反应(real-time fluorescence quantitative polymerase chain reaction,RTFQ-PCR)和蛋白质印迹法(Western blot)分别在mRNA和蛋白质水平上评估PTTG1沉默效率,进一步检测其对SHG44细胞增殖、凋亡、迁移和侵袭能力的影响。结果:沉默PTTG1基因表达可以显著抑制SHG44细胞增殖(P<0.05)、迁移(P<0.01)和侵袭(P<0.001)能力,增加细胞凋亡(P<0.05)。结论:下调PTTG1的表达可以降低神经胶质瘤的恶化程度,有望成为临床胶质瘤治疗的新靶点。福建省自然科学基金(2016D019);;\n福建省卫计委医学创新项目(2016-CXB-12

    SDF-1α/CXCR4信号通路对轴向应力刺激促进骨再生中影响的实验研究

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    目的 通过轴向应力刺激促进骨再生,观察基质细胞衍生因子1α/趋化因子CXC亚族受体4(stromal cell-derived-factor-1α/cysteine X cysteine receptor 4,SDF-1α/CXCR4)信号通路变化,探讨轴向应力刺激促进骨再生的机制。方法 取72只雄性新西兰大白兔,于右后肢胫骨近端内侧制备直径8 mm圆形皮质骨缺损并脱蛋白松质骨支架修复模型后,随机分为3组(n=24)。A组腹腔注射PBS,B组术肢给予应力刺激治疗+腹腔注射PBS,C组术肢给予应力刺激治疗+腹腔注射CXCR4拮抗剂(AMD3100)。术后2、4、8、12周,摄X线片并采用Lane-SandhuX线评分标准评价骨愈合情况,取标本行HE染色观察新生骨组织及支架降解,免疫组织化学染色观察VEGF、CXCR4表达水平;4、8周取标本Western blot检测SDF-1α及CXCR4蛋白表达水平。12周行Micro-CT检查,计算新生骨体积及新生骨密度。结果 X线片检查示,除术后2周各组骨缺损区及支架无明显变化外,4、8及12周时B组骨愈合评分均优于A、C组(P<0.05)。12周时Micro-CT扫描可见B组骨缺损修复、髓腔再通,新生骨体积及骨密度均高于A、C组(P<0.05)。HE染色显示,术后4周开始B组骨再生及支架降解均明显快于A、C组。免疫组织化学染色示,各组VEGF及CXCR4阳性表达均在4周时达峰值;各时间点B组VEGF及CXCR4表达量均显著高于A、C组(P<0.05)。Western blot检测显示,4、8周时B组SDF-1α与CXCR4表达量均显著高于A、C组(P<0.05)。结论 轴向应力刺激促进骨再生可能与其促进骨缺损区组织高表达SDF-1α,激活与其下游调控BMSCs募集的CXCR4信号有关

    SDF-1α/CXCR4信号通路在轴向应力刺激促进骨再生中的作用研究

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    目的通过轴向应力刺激促进骨再生,观察基质细胞衍生因子1α/趋化因子CXC亚族受体4(stromal cell-derived factor 1α/cysteine X cysteine receptor 4,SDF-1α/CXCR4)信号通路变化,探讨轴向应力刺激促进骨再生的机制。方法取72只雄性新西兰大白兔,于右后肢胫骨近端内侧制备直径8 mm圆形皮质骨缺损并脱蛋白松质骨支架修复模型,随机分为3组(n=24)。A组腹腔注射PBS,B组术肢给予应力刺激治疗+腹腔注射PBS,C组术肢给予应力刺激治疗+腹腔注射CXCR4拮抗剂(AMD3100)。术后2、4、8、12周,摄X线片并采用Lane-Sandhu X线评分标准评价骨愈合情况,取标本行HE染色观察新生骨组织及支架降解,免疫组织化学染色观察VEGF、CXCR4表达水平;4、8周取标本Western blot检测SDF-1α及CXCR4蛋白表达水平;12周行Micro-CT检查,计算新生骨体积及新生骨密度。结果 X线片检查示,除术后2周各组骨缺损区及支架无明显变化外,4、8及12周时B组骨愈合评分均高于A、C组(P<0.05)。12周时Micro-CT扫描可见B组骨缺损修复、髓腔再通,新生骨体积及骨密度均高于A、C组(P<0.05)。HE染色显示,术后4周开始B组骨再生及支架降解均明显快于A、C组。免疫组织化学染色示,各组VEGF及CXCR4阳性表达均在4周达峰值;各时间点B组VEGF及CXCR4表达量均显著高于A、C组(P<0.05)。Western blot检测显示,4、8周时B组SDF-1α与CXCR4表达量均显著高于A、C组(P<0.05)。结论轴向应力刺激促进骨再生可能与其促进骨缺损区组织高表达SDF-1α,激活与其下游调控BMSCs募集的CXCR4信号有关。国家自然科学基金资助项目(81401783);;\n福建省自然科学基金资助项目(2016J05208);;\n军队后勤科研项目基金(CNJ16C013);;\n军队青年医学科技培育项目(19QNP046)~
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