共查询到20条相似文献,搜索用时 187 毫秒
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提出了在多元弱酸(碱)平衡体系中各种平衡型体浓度精确求解的新处理方法。抽象出一般性精确浓度数值解法的数学模型和算法框图。计算过程实用、新颖。 相似文献
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通过比较同体积、不同浓度的草酸溶液与同体积、同浓度的酸性高锰酸钾溶液反应时溶液褪色时间的不同,使学生体会反应物浓度对反应速率的影响。为适应课堂教学,研究了各种反应物浓度对该反应速率的影响,为一线教师配置适合课堂教学的各种反应物的浓度提供了较为准确的数据。 相似文献
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高湿度条件下分解高浓度O3催化剂的研究 总被引:4,自引:0,他引:4
O3 (臭氧 )具有极强的氧化能力 ,因此被广泛地用于水和空气的除臭、杀菌以及染料废水的脱色、COD的去除及芳香族有机物的降解[1,2 ] 。但O3 是一种毒性物质 ,处理过程中剩余的O3 排放到空气中会造成环境污染。目前 ,处理含O3 尾气的方法主要有活性炭吸附法、药液吸收法、高温热解法和催化分解法[1] ,其中催化分解法不仅有高的分解率 ,而且满足长期稳定、安全、经济等要求 ,是较为理想的O3 分解方法。催化分解法使用的催化剂主要有含Mn催化剂、含Ti催化剂和过渡金属催化剂等。各种催化剂在低湿度条件下的催化性能都比较好 ,但在… 相似文献
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提出一种微混合器混合性能的评价方法.在样品盒中注入不同浓度罗丹明B溶液并用体视显微镜观察捕获图像,通过Image J软件读取图像灰度值,建立不同深度下溶液的浓度-灰度值函数关系,运用此关系式将T型微混合器3种不同深度(0.1、 0.2和0.4 mm,质量浓度0.05 %的罗丹明B溶液和去离子水作为配对流体)混合实验中捕获的图像中各像素点上的灰度值转换为浓度值,绘制浓度等高线图及浓度频数分布图,分析各自混合情况,最后引入浓度混合指数概念及计算公式,分析3种深度混合器内不同截面上的混合程度.此方法从定性和定量两方面分析了微尺度下混合腔深度对微混合的影响程度,具有一定的应用价值. 相似文献
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关于酸碱浓度与缓冲溶液pH值关系的新探讨汪乃兴,王彦刚(复旦大学化学系,上海200433)缓冲溶液作为各种反应和过程的载体或介质,具有稳定溶液反应环境的作用,可以说这是缓冲溶液最大的作用。但我们所说的稳定溶液环境,并不是说溶液环境绝对不变,而是说溶液... 相似文献
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基于光纤折射率传感原理的表面活性剂临界胶束浓度测定方法 总被引:1,自引:0,他引:1
提出并研究了一种新颖的基于光纤折射率传感原理的表面活性剂临界胶束浓度(cmc)测定方法.应用此方法测定有代表性的阴离子表面活性剂十二烷基硫酸钠(SDS)与阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)在25℃下的cmc分别为8.05×10-3和9.11×10-4mol·L-1,与文献值比较,结果相当吻合.从而证实了本方法的准确性.进一步研究了各种条件对测量表面活性剂cmc的影响,结果表明温度和无机盐NaCl的加入对本方法测量的准确性影响小,证明了本方法对测试环境的要求不苛刻,适用性好.最后对本方法进行了重复性和稳定性测试,相对标准偏差(RSD)为0.17%,与预期符合,效果良好. 相似文献
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1 装置的制作与实验步骤 目的:测定电解质溶液的浓度及自然界中空气及水中的离子的含量.(根据应用不同、可用不同材料做成各种样式,现举最常用的一种) 相似文献
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毕赤酵母作为一种高效的外源蛋白表达平台,其蛋白表达水平与胞内代谢物浓度紧密相关.但胞内代谢物种类多、物化性质差异大、浓度低、周转快,对其绝对浓度的精确检测一直难于实现.本研究将超高效液相色谱-三重四极杆质谱联用分析方法与13C同位素标记技术相结合,探索解决该难题的方法.首先,优化了超高效液相色谱的操作条件,利用3种色谱柱实现了64种常见中间代谢物的分离;对三重四极杆质谱仪的检测离子对和碰撞电压等操作条件进行优化,找到了对各种物质具有专一性的检测离子对.然后,利用全标记13C标记底物培养细胞,收集胞内的全标记代谢物用作定量内标物,建立了53种中间代谢物的标准曲线.实验结果表明,本方法不但精确性高,标准曲线相关系数达到0.99以上,而且重现性好,受实验条件和仪器操作条件的影响很小.将本方法应用于毕赤酵母胞内代谢物浓度的绝对定量分析,成功获得了胞内各种代谢物的浓度水平,为后续深入研究毕赤酵母代谢调控机理,实现外源蛋白的高效生产奠定了基础. 相似文献
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Current trends in the detection of peroxide-based explosives 总被引:1,自引:0,他引:1
The increased use of peroxide-based explosives (PBEs) in criminal and terrorist activity has created a demand for continued
innovation in the detection of these agents. This review provides an update to a previous 2006 review on the detection of
PBEs, with a focus in this report on luminescence and fluorescence methods, infrared and Raman spectroscopy, mass spectrometry,
and electrochemical techniques. Newer developments in gas chromatography and high performance liquid chromatography methods
are also discussed. One recent trend that is discussed is an emphasis on field measurements through the use of portable instruments
or portable assay formats. An increase in the use of infrared spectroscopy and mass spectrometry for PBE analysis is also
noted. The analysis of triacetone triperoxide has been the focus in the development of many of these methods, although hexamethylene
triperoxide diamine has received increased attention in PBE detection during the last few years. 相似文献
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Potential of thermo-optical methods for the study of molecular layers bonded to a flat glass surface
D. A. Nedosekin M. Yu. Kononets M. A. Proskurnin T. Yu. Chaikovskii G. V. Lisichkin 《Journal of Analytical Chemistry》2007,62(2):126-135
Thermal-lens spectrometry and photothermal deflection spectroscopy (mirage-effect spectroscopy) are used to study active bright red 5SKh bonded to a glass surface. The theoretically calculated dependence of the thermal-lens signal on the absorbance of the surface-absorbing layers on a nonabsorbing substrate is used to evaluate the concentration of the reagent in the bonded layer. The concentration of the reagent varies in the range of (2–8) × 10?11 mol/cm2, depending on the method of surface modification. Using photothermal deflection spectroscopy, it is shown that the thickness of the layer on the glass surface does not exceed 700 nm. Data obtained by the thermo-optical methods are supplemented with the results of the analysis of the surface relief obtained using electron microscopy in the secondary electron emission mode, and the uniformity of the modification of the sample surface is characterized. Based on the obtained data, a comparative analysis is performed for the potential of the considered methods for the investigation of the molecular layers bonded to the flat glass surface. 相似文献
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The application of NMR spectroscopy, including its up-to-date versions (correlation homo- and heteronuclear spectroscopy, Overhauser effect, solid-state NMR, etc.), to the analysis of tobacco and tobacco products, tea, and coffee is considered. The advantages and limitations of NMR techniques in the analysis of complex mixtures, as compared with chromatography-mass spectrometry and other instrumental techniques, are discussed based on particular examples. 相似文献
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Spark-source mass spectrometry, which is a typical bulk analysis technique, can also be used to study lateral profiles extending over millimeter distances, and for in-depth, layer and microsample analysis. Such analyses require knowledge of the influence of instrumental parameters such as breakdown voltage, pulse repetition frequency, pulse length and slit settings on the material consumed per spark pulse or per unit time, on the crater dimensions and on the ion yield. A study for over 20 matrices is reported. Applications are for lateral analysis (diffusion profile of beryllium in a Cu/CuBe diffusion couple), in-depth analysis (diffusion profile of nickel in copper), layer analysis (carbon in 3-μm gold layers, 3-μm GaAs epitaxial layer) and of microsample analysis (water residues). The effect of the amount of material sampled per analysis on the obtainable precision is demonstrated. 相似文献
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纤维染料是使纤维着色的物质,其分析检测对纺织、环保、法庭科学、古文物研究等诸多领域都有重要的意义。然而纤维染料的种类繁多、成分复杂,加之高灵敏度以及原位无损检测的分析需求日益突出,使得纤维染料的分析面临挑战。尽管如此,研究人员一直致力于高效、灵敏、无损的纤维染料分析新方法和新技术的研究,目前已经开发了多种纤维染料的分析方法,这些方法可大致分为3类:光谱法、色谱法及质谱法。该文综述了纤维染料的特点及纤维染料的检测方法及最新研究进展,并对未来纤维染料检测方法的发展进行了展望,为更好地开展纤维染料的分析提供了参考。 相似文献
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M. V. Trenikhin A. G. Kozlov A. I. Nizovskii V. A. Drozdov A. V. Lavrenov A. V. Bubnov V. P. Finevich V. K. Duplyakin 《Russian Journal of General Chemistry》2007,77(12):2320-2327
The best known procedures for aluminum activation are discussed and systematized. The analysis of published data and of results of the proper physicochemical research reveals that the phenomena of surface distribution, intergrain penetration and the internal diffusion in the crystal grains underlie the nature of aluminum activation with liquid metal alloys based on gallium. The experimental investigation using X-ray fluorescent spectroscopy of diffusion processes in the systems Al-Ga-In were performed for the first time. The procedures for formation of catalytically active complexes of AlCl3 type by treating the activated aluminum in situ in reaction media with chlorinated hydrocarbons were considered. 相似文献
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Development and trends of biosurfactant analysis and purification using rhamnolipids as an example 总被引:2,自引:0,他引:2
Heyd M Kohnert A Tan TH Nusser M Kirschhöfer F Brenner-Weiss G Franzreb M Berensmeier S 《Analytical and bioanalytical chemistry》2008,391(5):1579-1590
During the last few decades, increasing interest in biological surfactants led to an intensification of research for the cost-efficient
production of biosurfactants compared with traditional petrochemical surface-active components. The quest for alternative
production strains also is associated with new demands on biosurfactant analysis. The present paper gives an overview of existing
analytical methods, based on the example of rhamnolipids. The methods reviewed range from simple colorimetric testing to sophisticated
chromatographic separation coupled with detection systems like mass spectrometry, by means of which detailed structural information
is obtained. High-performance liquid chromatography (HPLC) coupled with mass spectrometry currently presents the most precise
method for rhamnolipid identification and quantification. Suitable approaches to accelerate rhamnolipid quantification for
better control of biosurfactant production are HPLC analysis directly from culture broth by adding an internal standard or
Fourier transform infrared attenuated total reflectance spectroscopy measurements of culture broth as a possible quasi-online
quantification method in the future. The search for alternative rhamnolipid-producing strains makes a structure analysis and
constant adaptation of the existing quantification methods necessary. Therefore, simple colorimetric tests based on whole
rhamnolipid content can be useful for strain and medium screening. Furthermore, rhamnolipid purification from a fermentation
broth will be considered depending on the following application. 相似文献
20.
Becker JS Breuer U Westheide J Saprykin AI Holzbrecher H Nickel H Dietze HJ 《Analytical and bioanalytical chemistry》1996,355(5-6):626-632
For the trace analysis of impurities in thick ceramic layers of a solid oxide fuel cell (SOFC) sensitive solid-state mass spectrometric methods, such as laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and radiofrequency glow discharge mass spectrometry (rf-GDMS) have been developed and used. In order to quantify the analytical results of LA-ICP-MS, the relative sensitivity coefficients of elements in a La(0.6)Sr(0.35)MnO(3) matrix have been determined using synthetic standards. Secondary ion mass spectrometry (SIMS) - as a surface analytical method - has been used to characterize the element distribution and diffusion profiles of matrix elements on the interface of a perovskite/Y-stabilized ZrO(2) layer. The application of different mass spectrometric methods for process control in the preparation of ceramic layers for the SOFC is described. 相似文献