共查询到20条相似文献，搜索用时 93 毫秒
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本文就近年来原子吸收光谱分析溶样方法的研究作一回顾和展望。同时重点讨论了微波溶样的原理、溶样体系及方法。针对生物和食品样品的溶样方法予以介绍。 相似文献
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本对铝合金中钛含量的传统分析法作了改进，改进后的分析方法在酸碱溶样后，用过氧化氢比色法分析，能克服传统方法的不足，取得了良好的测定效果。 相似文献
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氢化物发生——原子荧光法测定中草药中的痕量砷 总被引：1，自引：0，他引：1
本文采用高压溶样方式,应用AFS-2202a型双道原子荧光分光光度计,建立了氢化物发生-原子荧光测定中草药中砷的测定方法,研究了硼氢化钾浓度、灯电流、原子化器高度、载气流量等因素对测定结果的影响,用工作曲线法测定了四种中草药样品中砷的含量。 相似文献
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微波消解冷原子吸收光谱法测定环境土壤中微量汞 总被引：2，自引：0，他引：2
该文提出以微波溶样技术消解样品、冷原子吸收光谱法测定环境土壤中的微量汞.对冷原子吸收测定汞的光度条件及微波消解条件进行了优化,并对共存离子的干扰和方法的精密度进行了试验.结果表明,本法具有简便、灵敏、选择性好、线性范围宽等特点. 相似文献
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样品制备技术是农药多残留分析的关键．本文回顾了农药多残留分析样品制备技术的研究现状,着重介绍了固相萃取、固相微萃取、基质固相分散萃取、分散固相萃取、凝胶渗透色谱、超临界流体萃取、加速溶剂萃取的基本原理及在农药多残留分析中的应用情况,并对这些技术在农药多残留分析中的应用情况进行比较,展望了农药多残留分析样品制备技术的发展趋势。 相似文献
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用于同位素分析的锆石样品的系统制备方法 总被引：1，自引：0，他引：1
锆石样品制备是基于锆石同位素分析的基础.锆石制备环节复杂,混杂和难选是主要难题.基于大量锆石样品分析工作,提出和例释了系统制备方法.系统制备方法对制备各个环节进行记录和标记,有利于避免锆石混杂,同时便于难选样品的二次分选. 相似文献
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AbstractStudies of individual environmental education (EE) field trip programs have found that pre-visit preparation and post-visit follow-up activities can enhance desired student outcomes. We examined these relationships across a broad sample of single-day EE field trip programs for adolescent youth (grades 5-8) across the United States. We measured student outcomes, reflecting environmental literacy, 21st century skills, positive youth development, and student learning, through end-of-visit retrospective student surveys and follow-up surveys with visiting teachers two weeks after the field trip. Pre-visit logistical preparation as well as both pre-visit preparation and post-visit follow-up related to the subject matter were each associated with more positive student outcomes. The study provides further evidence across a large sample of programs that pre-visit preparation and post-visit follow-up can have meaningful impacts on student outcomes for EE field trips. We discuss the implications of the findings and provide examples and guidance for future programming efforts. 相似文献
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This study examined data from a random sample of 500 White students and 500 African American students who have taken the Community College Student Experiences Questionnaire to determine which factors in the environment impact their career preparation. The results showed that interaction with faculty had the strongest impact on career preparation for all students. Counseling services were significant for African American students. The African American students indicated they put more effort into student-faculty interactions and peer interactions than White students, and they reported greater gains in career preparation. 相似文献
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Alison A. Carr 《Performance Improvement Quarterly》1997,10(1):125-140
This article explores the unique positioning of leadership theory and literature as a unifying and informing discipline for the preparation of performance technologists. Although the role of leadership could be emphasized in any of the settings in which performance technologists become skilled, university departments of educational leadership seem especially suited for programs with this emphasis. A sample course activity is shared and linked to the building of leadership skills. The purpose of this article is to describe the importance of leadership as an informing and unifying discipline for the preparation of performance technologists and to explore the impact of this orientation on performance technologist preparation. 相似文献
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介绍了分析化学实验教学改革的几种实践 :严格实验预习制度、使用未知试样、加强实验内容与生产生活实际及专业的联系、学生参与实验准备、建立开放性实验室、严格实验成绩评分制度 相似文献
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《Educational Assessment》2013,18(3):259-277
This study investigated the extent and nature of preparation for the Pre-Professional Skills Tests (PPST), and the reasons for preparing or not preparing. The PPST, a high-stakes test with a high failure rate, is used for admission to teacher education programs and for teacher licensing. Recent test takers were surveyed. Preparation was limited and mainly involved activities that were free or inexpensive, such as taking a sample test. The reported reasons for not preparing and the empirical correlates of measures of preparation were primarily attitudinal. 相似文献
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侯芳 《洛阳工业高等专科学校学报》2010,20(1)
从样品的前处理和检测方法两个方面综述了茶叶中重金属的检测。前处理方法包括灰化法、消化法、微波消解、高压消解、酸提取法及悬浮液直接进样法等,检测方法包括原子光谱法、电化学法、电感耦合等离子体质谱法和分光光度法等。 相似文献
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Determination of benzalkonium chloride in viscous ophthalmic drops of azithromycin by high-performance liquid chromatography 总被引：1，自引：0，他引：1
Yan Shen Sheng-jie Xu Shi-chun Wang Jia-sheng Tu 《Journal of Zhejiang University. Science. B》2009,10(12):877-882
A high-performance liquid chromatography (HPLC) system was used in the reversed phase mode for the determination of benzalkonium chloride (BKC) in azithromycin viscous ophthalmic drops. A Venusil-XBP(L)-C_(18) (150 mm×4.6 mm, 5 μm) column was used at 50 ℃. The mobile phase consisted of a mixture of methanol-potassium phosphate (16:5, v/v). Two sample preparation methods were compared. The results suggested that, compared with an extraction procedure, a deproteinization procedure was much quicker and more convenient. Using the deproteinization procedure for sample preparation, calibration curves were linear in the range 5.0～50 μg/ml. The within-day and inter-day coefficients of variation were less than 10%. The average recoveries were determined as 96.70%, 98.52%, and 97.96% at concentrations of 10.0, 30.0, and 50.0 μg/ml, respectively. Variability in precision did not exceed 5%. In conclusion, this HPLC method using a simple sample treatment procedure appears suitable for monitoring BKC content in azithromycin viscous ophthalmic drops. 相似文献