Design considerations and an example of application of an in-house made TG-MS interface

The design, the abilities and a characteristic application of an in-house made interface for combining thermogravimetry (TG) with mass spectrometry (MS) are presented. The TG-MS interface consists mainly of three co-axial tubes. The position of the intermediate tube was determined after calculation of the temperature profile at the TG furnace exit tube. The inner tube position was determined taking into consideration its protection against condensation of heavy molecules and the time delay for the transfer of the evolved gases. This interface allows either continuous sampling and transferring of the evolved gases from the TG to the MS or repetitive introduction of short sampling pulses of TG evolved gases to MS. The interface is capable of coupling various commercial instruments. In the present work two configurations of this interface are demonstrated. Finally an example of application of this interface on forest fuel pyrolysis is presented. This revised version was published online in July 2006 with corrections to the Cover Date.     

Effects of Amplitude of the Radiofrequency Electromagnetic Radiation on Aqueous Suspensions and Solutions

The effects of radiofrequency (RF) (1–4) and magnetic fields (5–9) on the behavior of aqueous solutions and suspensions have been a popular subject in recent years. The mechanism of the magnetic “water memory” effect, though, is still largely unknown (5). In this work, we present evidence that the primary “receptor” of the electromagnetic radiation is a gas/liquid interface. Gas can be either already present in water or produced by the effects of electromagnetic fields. Perturbed gas/liquid interfaces require hours to equilibrate. Certain RF and magnetic signals also produce reactive oxygen and hydrogen species (superoxide, hydrogen peroxide, hydrogen, atomic hydrogen). The perturbed gas/liquid interface modifies the hydrogen bonding networks in water and also the hydration of ions and interfaces. Careful outgassing removes all of the effects of the electromagnetic fields, including the magnetic memory effect. The amplitude of the applied field influences the observed effects. Different amplitudes of RF radiation perturb the interfacial water in different ways and consequently affect the behavior of colloids and ions in specific manners. For instance, the bulk and template precipitation of calcium carbonate, zeta potentials of suspended colloids, rate of dissolution of colloidal silica, and attachment of colloidal silica to metal surfaces are modified in specific ways with the low amplitude or high amplitude RF treatments described in this paper. The solubility/diffusivity of gas species is also modified in a different manner, and it is probably at the core of the specificity of the RF amplitude effects.     

碳氟链与碳氢链表面活性剂在固液界面上的吸附

全氟辛酸及其钠盐和十二烷基硫酸钠在R972上的吸附等温线均为S型或LS型，指示固液界面吸附过程中有表面疏水缔合物生成．碳氟表面活性剂的饱和吸附量显著高于碳氢表面活性剂的饱和吸附量．加电解质于液相使各体系吸附量上升．对于碳氟表面活性剂，甚至引起吸附等温线类型变化．例如，不加电解质时全氟辛酸在R972上的吸附等温线为S型，而加入HCl（c＝0．05mol·dm－3）使吸附等混线变成LS型．全氟辛酸比全氟辛酸钠在R972上的吸附更强．几种表面活性剂在R972上的吸附均随温度升高而减少。应用两阶段吸附模型及通用吸附等温线公式可以很好地解释所得实验结果．     

Ternary surface complexes by theE(%)-pH curve method

A new method for the study of ternary surface complexes at liquid-solid interface, theE(%) -pH curve method, was proposed. Four types ofE(%)-pH curves, namely, phenomenon of left-right shifts of S-shaped curve, V-shaped curve, monodirection shift curve and X-shaped curve, were discovered. Correspondingly, apart from type (I) ternary surface complex and type (II) ternary surface complex , a new type of ternary surface complex was discovered. Project supported by the National Natural Science Foundation of China and the Fund of Doctoral Degree’s Spot.     

A generalized equation describing isotope exchange kinetics at solid-liquid interface

A generalization of the kinetic equation for the isotope exchange at solid—liquid interface is presented. The generalized equation may be used to describe kinetics of the isotope exchange process limited by surface reactions and diffusion without assumption of spherical symmetry of solid particles.

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Eine generalisierte Gleichung für die Kinetik des Isotopenaustausches an Fest-Flüssig-Phasengrenzen

Zusammenfassung Es wird eine generalisierte kinetische Gleichung angegeben, die die Kinetik des Isotopenaustausches an Fest-Flüssig-Phasengrenzen beschreibt, wobei der Austauschprozeß durch Oberflächenreaktionen und Diffusion ohne der Annahme sphärischer Symmetrie für die festen Partikel begrenzt ist.

     

Formal Mathematical Analysis of the Existence of the Common Intersection Point in Relation to Determining the Parameters Describing Ion Adsorption at the Oxide/Electrolyte Interface: Comparison of the Triple and Four-Layer Models

For most oxide/electrolyte systems potentiometric titration curves measured for different ionic strengths have a Common Intersection Point (CIP) which corresponds to the Point of Zero Charge (PZC). However, there are systems where a CIP exists but the surface charge at this point does not equal zero (PZC CIP). In this paper theoretical analysis of the systems in which the PZC and CIP do not coincide is presented. It is based on the well-known 2-pK surface charging approach and Triple Layer Model (TLM) as well as the Four Layer Model (FLM) of the electric double layer. The appropriate mathematical criterion for CIP existence was applied with detailed derivations, both for TLM and FLM. Having determined in this manner the parameter values, one can draw proper conclusions about the features of oxide/electrolyte adsorption systems, in which PZC and CIP do not coincide. The values of adsorption parameters are found by fitting simultaneously the obtained theoretical expressions to both of the experimental titration isotherms, and to the individual isotherms of electrolyte cation adsorption measured using radiometric methods.     

Surface mixed adsorption films of 2,4,6- trimethylphenol–2,4,6-trichlorophenol at aqueous solution/air interface

 The results of experimental studies of the adsorption at the solution/air interface from an aqueous mixture: 2,4,6-trimethylphenol–2,4,6-trichlorophenol are presented. The surface properties of the above-mentioned mixture were studied by surface potential and surface tension measurements. These measurements were carried out as a function of the concentration of 2,4,6-trimethylphenol aqueous solution at a constant concentration of 2,4,6-trichlorophenol. Using the results obtained and based on the Gibbs equation, Helmholtz formula and Motomura’s method the relative surface excesses of adsorbed substances, effective dipole moments, surface molar fractions of solutes and miscibility of adsorbed films were determined. Received: 7 November 1997 Accepted: 26 February 1998     

Pb2＋在液/液界面迁移的电化学研究及其应用

用循环伏安法研究了双硫腙络合推动Pb^2＋在水/乙酰丙酮界面迁移的伏安过程. 实验证明, 该过程是受扩散控制的不可逆过程, Pb^2＋由水相转移到有机相中, 与双硫腙形成络合物Pb(DzH)₂. Pb^2＋的峰电位在－0.3 V处, 并且在5× 10^－6～0.1 mol•L^－1范围内与峰电流成正比. 这一方法为工业废水中铅的在线、现场测定提供了可靠、灵敏的检测方法.     

New formulation of restricted growth processes

We present a new formulation of a class of growth models-those which evolve according to an exclusion process. This formulation is based upon a transformation of the probability distribution function which involves Grassmann variables. This method is very general and enables one to derive an exact stochastic differential equation for the model of interest. We describe this method using the traffic model as an example.     

A novel conversion of erythro phospholane epoxides to one-carbon atom homologated allylic alcohols

A novel synthetic approach is described to incorporate one more carbon atom at C-2 position of phospholane oxides as homologated allylic alcohol by treatment of erythro-2,3-epoxy-3-methylphospholane 1-oxides with excess of dimethylsulfonium methylide.