共查询到20条相似文献,搜索用时 265 毫秒
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盐水振荡与液膜振荡耦合 总被引:1,自引:0,他引:1
为进一步增大盐水振荡产生的电势差,并使盐水振荡可逆,该文将液膜振荡与盐水振荡耦合,组成一个耦合的振荡器.实验结果发现:(1)由于两振荡器耦合形成共振,所以此耦合振荡器的振幅明显增大; (2)耦合后的化学振荡器变为可逆振荡器.耦合振荡机理如下:扩散过程中形成的缔合物存于油相,难溶于水,通电后缔合物发生解离,因此造成反扩散,形成可逆振荡,且可逆程度及逆反应产生的电势差(即振幅)大大提高,扩展了盐水振荡在二次电池开发方面的应用. 相似文献
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β-胡萝卜素微乳液的制备及其稳定性研究 总被引:9,自引:0,他引:9
通过绘制拟三元相图选择合适的微乳液组分,制备了β-胡萝卜素的Tween80/乙醇/丁酸乙酯/H2O的O/W型微乳液。考察了温度、盐度和pH对微乳液区域的影响:电导率法区分了微乳液的O/W、W/O和B.C(油-水双连续型)区域;对相同浓度β-胡萝卜素的微乳液和丁酸乙酯溶液进行了光、热稳定性研究,用紫外分光光度法测定样品中β-胡萝卜素的残存率。结果表明,温度升高和pH降低使微乳区稍有减小,盐度对微乳区基本无影响;微乳体系中水的质量分数大于61·5%时形成O/W型微乳液;β-胡萝卜素在微乳液和丁酸乙酯溶液中对光和热都比较敏感,但在微乳液中较稳定。 相似文献
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支撑液膜在线萃取富集流动注射分光光度法测定水中痕量苯胺 总被引:11,自引:0,他引:11
选用无毒性的磷酸三丁酯为载体,煤油为膜溶剂的支撑液膜萃取体系,建立了支撑液膜在线萃取富集流动注射分光光度法测定河水中苯胺的新方法。对实验条件进行了优化。实验结果表明:在内相pH=2,外相pH=11,膜相组成为15%TBP-85%煤油,富集时间为13min的最优条件下,方法的检出限为0.04mg/L;线性范围为0.1-4mg/L。应用于河水中痕量苯胺的检测,结果满意。 相似文献
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膜/液界面浓度极化现象的介电解析 总被引:1,自引:0,他引:1
对由强、弱荷电膜和溶液构成的膜/液非均匀体系,在10-107Hz频率范围进行了介电测量,在直流偏压下,该体系显示了二个显著的介电弛豫.利用具有电导率分布相,即浓度极化相的介电理论对强行电的离子交换膜的结果进行了介电解析,从实验上测得的介电参数求出了反映膜/液界面浓度极化层构造的参数,讨论了该体系产生介电弛像的原因、说明了介电理论的合理性,并提出了膜/液界面体系产生介电弛豫现象的可能机理. 相似文献
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十二烷基硫酸钠油水体系液膜振荡及其与无机酸的影响 总被引:1,自引:0,他引:1
十二烷基硫酸钠油水体系液膜振荡及其与无机酸的影响吴英(贵州农学院基础部贵阳550025)关键词十二烷基硫酸钠,液膜,电势振荡,无机酸本文研究了蔗糖(aq)/1.10邻菲啉十硝基乙烷/十二烷基硫酸钠(aq)十乙醇液膜振荡体系,获得有规律的界面电势振荡曲... 相似文献
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A new type of oscillating reaction was found from the systematic design of the chemical oscillator in water in oil (W/O) emulsions. It is an acidity hydrolysis reaction of long chain triglyceride in W/O emulsion at 25.0 ± 0.1°C in a bath stirring reactor. During the process of reaction, there were periodic and semi‐periodic changes lasting more than 10 hours both in electrolytic conductivity and electric potential. Microscope also revealed that the emulsion structure changed regularly and quickly. Because of the large difference in the solubility of the hydrolyzed products, it could be thought, that the different redistribution in the two phases of water and oil induces the regular changes. Marangoni effect of interface membrane made oscillation to form. The oscillating reaction can be used to explain the periodic change in the living system produced from coupling between reaction and diffusion. 相似文献
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The oscillatory behavior of a nitromethane based liquid membrane oscillator was investigated to contribute to the oscillation mechanism at the molecular level. At the beginning the system contains three phases: the aqueous donor phase in which the cationic surfactant, hexadecyltrimethylammonium bromide and ethanol are present and the aqueous acceptor phase made up by sucrose solution separated by the liquid membrane containing a constant amount of picric acid. During experiment a new phase x is created between the liquid membrane and acceptor phase. It was established that the oscillations take place at the membrane/phase x and the phase x/acceptor phase interfaces. Five basic regions can be distinguished in the oscillation pattern. The molecular events provoking the oscillations of electric potential difference between the two aqueous phases involve essentially the diffusion of hexadecyltrimethylammonium bromide and ion pairs formed by the cation of the surfactant and the picrate anion to the vicinity of the membrane/phase x interface, sudden adsorption of these ion pairs at this interface in noncatalytic and autocatalytic steps, desorption of ion pairs from the membrane/phase x interface into phase x, diffusion of ion pairs to the vicinity of phase x/acceptor phase interface, and sudden adsorption at this interface followed by desorption to the aqueous acceptor phase. It is shown by numerical simulations that the proposed mechanism may account for the observed oscillations and for the species distribution throughout the system as found experimentally. This four-phase system behaves like two coupled oscillators. 相似文献
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The oscillatory behavior of a liquid membrane oscillator with anionic surfactant was investigated in order to understand the oscillation mechanism at the molecular level. As a theoretical framework, an approach based on chemical kinetics laws has been used. The chosen system involved nitromethane with 2,2(')-bipyridine as liquid membrane. The aqueous donor phase contained sodium oleate and butanol, while sodium chloride was added to the aqueous acceptor phase. It was established that the oscillations take place exclusively at the aqueous acceptor phase/membrane interface. Therefore, liquid membrane oscillators with anionic surfactants behave the same way as oscillators with cationic surfactants as to the location of oscillations. An oscillation mechanism involving three stages is proposed and confirmed by numerical simulations. The oscillations of electrical potential differences between the two aqueous phases are produced by sudden adsorption and desorption of anionic surfactant in solvated form and butanol at the acceptor/membrane interface. The whole process is controlled by the slow diffusion of these species across the liquid membrane. The chaotic character of the oscillations was demonstrated by Lyapunov exponents obtained from the strange attractor of the system. 相似文献
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Steven A. Giannos Steven M. Dinh Bret Berner 《Macromolecular rapid communications》1995,16(7):527-531
The iodate pH oscillator, which oscillates between pH 6.5 and 4.0, is reproducible in a semibatch reactor. pH oscillations of similar period and amplitude were observed when poly(2-acrylamido-2-methyl-1-propanesulfonic acid) was substituted for sulfuric acid. Therefore, a polymer may be used as an alternative reagent, where the polymer actively participates in the reaction instead of serving as an inert reaction medium. 相似文献
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Kovacs K McIlwaine RE Scott SK Taylor AF 《Physical chemistry chemical physics : PCCP》2007,9(28):3711-3716
The Methylene Glycol-Sulfite-Gluconolactone (MGSG) reaction is the first example of an organic-based pH oscillator. This reaction is of particular interest as it displays large amplitude oscillations in hydroxide ion accompanied by small amplitude (10(-3) V) oscillations in potential, indicating that it is not driven by redox processes. We investigate the reaction in a batch (closed) and flow (open) reactor and examine the role of the aging of the gluconolactone stock solution. The system is found to display oscillations and bistability for a wide range of flow rates and initial compositions. The experimental results are reproduced in numerical simulations in an extended model of the reaction in which the decay of the stock solution is incorporated. Finally, we analyse the features of the reaction that make it a suitable basis for the development of novel pH oscillators. 相似文献
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高碘酸盐-硫脲-硫酸反应体系的非线性动力学 总被引:2,自引:0,他引:2
研究了KIO4 SC(NH2)2 H2SO4反应体系在封闭、半封闭以及开放系统中的非线性动力学行为.发现在封闭体系中体系的吸光度、铂电极电位和pH值呈现单峰或准振荡现象;在半封闭和开放系统中体系的铂电极电位和碘电极电位均呈振荡现象.封闭、半封闭及开放系统的动力学曲线受体系酸度和初始浓度比值[KIO4]0/[SC(NH2)2]0的影响.对照其在封闭、半封闭和开放系统中的动力学行为,以碘单质产生和消耗驱使的反应动力学可解释该反应体系的复杂现象. 相似文献
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A new type of bulk liquid membrane system, which represents the first example of a bulk liquid membrane oscillator characterised by the presence of two coupled oscillators, is described. When the benzyldimethyltetradecylammonium chloride surfactant undergoes an oscillatory mass transfer through a nitromethane liquid membrane, a new liquid layer (phase X) appears between the membrane and the acceptor phase. Kinetic analysis provides evidence that the whole system is composed of two coupled oscillators with diffusion-mediated physical coupling. The first component oscillator (based on nitromethane) of lower frequency delivers the driving material to the second one (phase X-based oscillator) leading to additional higher frequency oscillations. A new molecular mechanism is proposed for interpreting the experimental observations. The results might enhance understanding of intercellular communication in biology, where periodic signalling is more efficient than any other type of signalling mode. 相似文献
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In a recent paper, we suggested that the acid- or base-catalyzed dehydration of a hydrated carbonyl compound provides a suitable foundation for an organic-based pH oscillator. Here we present the first experimental example of such an oscillator in a flow reactor, utilizing the base-catalyzed dehydration of methylene glycol as a source of positive feedback (OH- autocatalysis) coupled with the base-catalyzed hydrolysis of gluconolactone for negative feedback (H+ production). The large amplitude oscillations (between pH 7 and 10) are reproduced in a kinetic model of the reaction. Such experiments present new possibilities in the design of pH oscillators. 相似文献
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Plocharska-Jankowska E Szpakowska M Matefi-Tempfli S Nagy OB 《The journal of physical chemistry. B》2006,110(1):289-294
Liquid membrane oscillators very frequently have an irregular oscillatory behavior. Fourier transformation cannot be used for these nonstationary oscillations to establish their power spectra. This important point seems to be overlooked in the field of chemical oscillators. A new approach is presented here based on Gábor transformation allowing one to obtain power spectra of any kind of oscillations that can be met experimentally. The proposed Gábor analysis is applied to a liquid membrane oscillator containing a cationic surfactant. It was found that the power spectra are strongly influenced by the presence of various added substances. 相似文献