原子吸收光谱法在烟草行业中的应用进展

对1961～2011年间3种类型的原子吸收光谱法,包括火焰原子吸收光谱法、石墨炉原子吸收光谱法和蒸气发生原子吸收光谱法在烟草行业中的应用进行了综述(引用文献63篇)。     

参比注射法测定液体的饱和蒸气压

参比注射法测定液体的饱和蒸气压赵国华，张舟，赵国菁，李光明（同济大学化学系，上海２０００９２）物理化学实验教学中，传统测定液体饱和蒸气压的方法主要有静态法、动态法和气体饱和法等三种￣［１，２］。由于这些方法大多采用了真空系统，整套实验装置体积较大，操...     

溶液冰点降低的P-T图讨论

讨论溶液冰点降低时,一些物理化学教材中常辅以P-T图做定性解释.这种解释有两种不同方法:一种是按照冰点时固态纯溶剂蒸气压和溶液蒸气压相等的原则解释,见图1示,另一种是按照一定压力下(通常为1 atm),固态纯溶剂和溶液两相平衡时温度为冰点的原则解释,见图2示.     

金属蒸气法制备高分散Co／SiO2催化剂及其研究

金属蒸气(原子)合成是本世纪六十年代末发展起来的一种新的合成技术。七十年代，人们主要利用这项技术合成新的无机和金属有机化合物。近年来，利用金属蒸气合成法合成新材料的报道不断涌现，其中最引人注目的是制备高分散负载零价金属催化剂叫。1988年     

介绍新型四球等位计

介绍静态法测定液体蒸气压的新型等位计技术的优点。给出了仪器图形和仪器的使用方法。同时给出了实验数据和实验结果,并与文献值做比较。     

扩大冷原子吸收光谱法在分析中应用的初步探讨

冷原子吸收光谱法测定汞是利用常温下金属汞蒸气压大,以及它在空气中不易被氧化的特性。将试样化学消化处理后制成溶液,用还原剂(如SnCl_2或KBH_4等)将汞离子还原为金属汞,再把汞蒸气导入石英吸收管中,并测量汞的冷蒸气对汞灯的特定波长的光辐射的吸收信号。该法灵敏度很高,快速、准确,且设备简单。已被广泛用于生物、水质、岩石、土壤等各种样品中痕量汞的测定,成为测定汞的常规方法。     

完全不互溶双液系的蒸气压*

对完全不互溶双液系的饱和蒸气压进行了实验研究与理论讨论,认为完全不互溶双液系的平衡蒸气压随两组分相互溶解度减小而趋于但总是小于两纯组分的饱和蒸气压之和;当完全不互溶两液相一起静置时,上层液体能有效但不能完全阻止下层液体的挥发,这种阻止作用源于缓慢溶解、扩散和挥发这些动力学过程;提出了阻止下层液体挥发的方法,即用与之完全不互溶且密度小的液体来覆盖,并且2种液体充满容器,阴凉处密闭静置保存。     

简易动态法测定液体饱和蒸气压的装置

测定液体饱和蒸气压的方法有静态法、动态法和饱和气体法。目前，国内大中专院校物理化学实验教材中多数采用静态法，虽然有些物理化学实验书［１，２］中，涉及动态法测定纯液体饱和蒸气压，但所用仪器和装置复杂，有的玻璃接头难以买到。我们设计了如下用动态法测液体蒸...     

金属蒸气法制备Ag／C燃料电池电极

自本世纪六十年代末 Timms 和 Skell发明金属蒸气合成技术以来,已有成千上万个化合物在金属原子反应器中诞生。近年来金属蒸气合成技术又在合成新材料方面显示出很有价值的应用前景。本文报道利用金属蒸气合成法制备 Ag/C 燃料电池电极的初步研究结果。     

测定液体饱和蒸气压的一种沸点计

纯组分的饱和蒸气压是物性的重要参数。化工生产中,蒸馏、吸收等过程的设计、开发或革新均离不开相平衡,因此饱和蒸气压是化工分离过程中不可缺少的热力学基础数据。这些数据在文献中虽能查找,但对于一些新材料、新物质或由于所用物料纯度等影响,以及所要求的温度、压力范围不同,都需要进行实验测定。欲测得准确的饱和蒸气压数据,必须使所测温度、     

纳米TiO2薄膜的制备方法

本文对纳米TiO₂薄膜的各种制备方法，包括基于溶胶－凝胶的涂层方法、电沉积、化学气相沉积、物理气相沉积、自组装制膜，以及喷雾热分解等方法的研究进展进行了综述，对不同方法的优缺点进行了比较和评述，对今后TiO₂薄膜制备的研究方法提出了一些建议。     

纳米TiO2薄膜的制备方法*

本文对纳米TiO₂薄膜的各种制备方法,包括基于溶胶－凝胶的涂层方法、电沉积、化学气相沉积、物理气相沉积、自组装制膜,以及喷雾热分解等方法的研究进展进行了综述,对不同方法的优缺点进行了比较和评述,对今后TiO₂薄膜制备的研究方法提出了一些建议。     

碳包覆纳米金属颗粒的合成研究进展

碳包覆纳米金属颗粒是继富勒烯和碳纳米管之后的又一新型纳米碳材料,在许多领域具有广泛应用前景。本文综述了碳包覆纳米金属颗粒的合成方法,包括：电弧放电法、化学气相沉积法、热解法、液相浸渍炭化法和炭凝胶爆炸法等,简述了形成机理,总结了各自的优缺点,并指出将来的发展方向。     

Sorption of water vapor on cation-substituted vermiculite

Deformations of Na, Ca, and Ba vermiculites upon sorption of water vapor have been determined by a dilatometric method. Sequential stages in the hydration of interlayer exchange cations have been identified. The experimental results have been compared with data obtained in studies using adsorptive, calorimetric, and x-ray methods.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Institute of Colloid Chemistry and the Chemistry of Water, Academy of Sciences of the Ukraine, Kiev. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 34–39, January, 1992.     

气相色谱-质谱分析气体样品的制备方法和技术

现代GC-MS仪器虽然具有较高的分辨能力和较高的灵敏度,但是对欲分析样品的要求也比较严格。诸如:进样量大小、组成组分的浓度范围、样品的物理状况、样品中的基体干扰等问题都是必须在进样之前调查清楚,才能选择正确的样品处理方法和技术并处理成GC-MS仪器能够直接进样测定的样品形式,获得正确的GC-MS分析测定结果。否则,就有可能应用盲目的样品处理方法和技术并获得了错误的GC-MS分析测定结果。根据错误的分析结果就会误导决策者做出错误的决定,由此造成人力和物力的浪费,或者贻误了时机并造成无法弥补的损失。     

Pervaporation, a novel technique for the measurement of vapor transmission rate of highly permeable films

The moisture vapor transmission rate (MVTR) of poly(ether-block-amide) breathable films were measured with a set-up based on the ASTM E96 E and BW methods. These methods led to reliable MVTR for films of low breathability, but not for films of high breathability. The latter shows MVTR values varying over a large range when the operating conditions are changed. An analysis of the mass and the heat transfers pointed out the crucial role of the transfer resistances in the external phases adjacent to the film. The pervaporation technique was designed to minimize these mass and heat transfer resistances using a powerful stirring of the upstream chamber and a good vacuum applied on the downstream chamber. The MVTR was determined from the weight of vapor condensed in a cool trap. The MVTR of films of high breathability were reliably determined by this method; their value was much higher than those obtained with the ASTM E96 BW method for the same films. The obtained intrinsic MVTR data suggest that (i) the film structure is more ordered at lower thickness, and (ii) the activation energy for water permeation is low, probably due to the high flexibility of polyether segments. The technique was successfully used for the measurement of a very high MVTR film made of poly(vinylalcohol), ca. 120 kg day⁻¹ m⁻², and for the measurement of the permeation rate of ethylacetate through a silicone rubber film.     

Fundamental restrictions of the second-law and Arrhenius plot methods used in the determination of reaction enthalpies in decomposition kinetics

The apparent increase of the reaction enthalpy ΔH with temperature due to the self-cooling and condensation effects is responsible for the fundamental restrictions of the second-law and Arrhenius plot methods related to determination of this parameter. Theoretical analysis and a comparison with the experimental data indicate that the systematic underestimation of ΔH magnitudes determined by the second-law method equals 10–25% for the reactants decomposed to gaseous products and 15–50% for reactants decomposed to solids. Therefore, the use of these methods in decomposition kinetics is hardly acceptable. The replacement of the Arrhenius plot and second-law methods to the much more precise and accurate third-law method is desirable or even obligatory.     

Precision of integral methods for the determination of the kinetic parameters

In this paper, a systematic analysis of the errors involved in the determination of the kinetic parameters (including the activation energy and frequency factor) from five integral methods has been carried out. The integral methods analyzed here are Coats-Redfern, Gorbachev, Wanjun-Yuwen-Hen-Zhiyong-Cunxin, Junmeng-Fusheng-Weiming-Fang, Junmeng-Fang and Junmeng-Fang-Weiming-Fusheng method. The results have shown that the precision of the kinetic parameters calculated by the different integral methods is dependent on u (E/RT), that is, on the activation energy and the average temperature of the process.     

Volatile Times for the Very First Ionic Liquid: Understanding the Vapor Pressures and Enthalpies of Vaporization of Ethylammonium Nitrate

A hundred years ago, Paul Walden studied ethyl ammonium nitrate (EAN), which became the first widely known ionic liquid. Although EAN has been investigated extensively, some important issues still have not been addressed; they are now tackled in this communication. By combining experimental thermogravimetric analysis with time of flight mass spectrometry (TGA‐ToF‐MS) and transpiration method with theoretical methods, we clarify the volatilisation of EAN from ambient to elevated temperatures. It was observed that up to 419 K, EAN evaporates as contact‐ion pairs leading to very low vapour pressures of a few Pascal. Starting from 419 K, the decomposition to nitric acid and ethylamine becomes more thermodynamically favourable than proton transfer. This finding was supported by DFT calculations, which provide the free energies of all possible gas‐phase species, and show that neutral molecules dominate over ion pairs above 500 K, an observation that is in nearly prefect agreement with the experimental boiling point of 513 K. This result is crucial for the ongoing practical applications of protic ionic liquids such as electrolytes for batteries and fuel cells because, in contrast to high‐boiling conventional solvents, EAN exhibits no significant vapour pressure below 419 K and this property fulfils the requirements for the thermal behaviour of safe electrolytes. Overall, EAN shows the same barely measurable vapour pressures as typical aprotic ionic liquids at temperatures only 70 K lower.