毛细管口气泡的曲率半径和附加压力变化

The profiles of the curved surface at critical status during formation of a bubble are drawn schematically, and the dependence of the radius of curvature on time is obtained in this work. The curve is useful for the students to better understand the evolution of radius of curvature and excess pressure in the laboratory experiment of surface tension measurements by the bubble pressure method, and helpful to interpret the exercises regarding excess pressure.     

Comparative Analysis of Acyclovir Esters Stability in Solutions: The Influence of the Substituent Structure,Kinetics, and Steric Effects

Reversed‐phase high‐performance liquid chromatography has been applied to the determination of acyclovir (ACV) esters such as acetate, isobutyrate, pivalate, ethoxycarbonate, and nicotinate. All analyses were carried out at laboratory temperature using a column LiChrospher RP‐18 (250 × 4 mm, 5 µm) and a proper mobile phase consisting of acetonitrile and phosphate buffer (pH 6 or 6.7) or acetonitrile and potassium dihydrogen phosphate, and acetic acid. The methods were validated by the determination of the following parameters: selectivity, precision, accuracy, and linearity. Kinetic studies on the hydrolysis were investigated in solutions at 310 K over the pH range 0.42–1.38. The pH‐profiles indicated specific acid‐catalyzed and spontaneous water‐catalyzed degradation. The stability of the studied ACV esters were determined not only by steric factors. In the case of ethoxycarbonyl ester of ACV, the hydrolysis was a two‐step reaction.     

最大泡压法测表面张力等温线的数据处理方法比较*

对乙酸、丙酸、正丁酸、2-甲基丁酸、3-甲基丁酸、正戊酸、正己酸、乙醇、丙醇、异丙醇、正丁醇、异丁醇、1,2-丙二醇等13种常用试剂在25 ℃下的表面张力数据拟合方法进行了比较,分析了图解法处理数据及多项式、一阶指数函数、幂函数、Shishkovsky经验公式拟合数据的优缺点。指出Shishkovsky经验公式拟合结果准确,受数据样本量影响小,是理想的表面张力数据拟合方法。     

Nonlinear Effects in Paul Traps Operated in the Second Stability Region: Analytical Analysis and Numerical Verification

Paul trap working in the second stability region has long been recognized as a possible approach for achieving high-resolution mass spectrometry (MS), which however is still far away from the experimental implementations because of the narrow working area and inefficient ion trapping. Full understanding of the ion motional behavior is helpful for solving the problem. In this article, the ion motion in a superimposed octopole field, which was characterized by the nonlinear Mathieu equation, was solved analytically using Poincare-Lighthill-Kuo (PLK) method. This method equivalently described the nonlinear disturbance by an effective quadrupole field with perturbed Mathieu parameters, a _u ^′ and q _u ^′ , which would bring huge convenience in the studies of nonlinear ion dynamics and was, therefore, used for rapid evaluation of the nonlinear effects of ion motion. Fourth-order Runge-Kutta method (4th R-K) indicated the error of PLK for characterizing the frequency shift of ion motion was within 15%. Figure

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Solutions,in Particular Dilute Solutions of Nonelectrolytes: A Review

Journal of Solution Chemistry - The liquid state is one of the three principal states of matter and arguably the most important one; and liquid mixtures represent a large research field of profound...     

Photochemical Reactions of Aminoazobenzene in Solutions,According to Ultrafast Vis Spectroscopy Data

Russian Journal of Physical Chemistry A - Photoinduced processes (photonics) in trans-aminoazobenzene (t-AAB) are determined by analyzing literature data on transient Vis spectra upon pulsed laser...     

Some Kinetic Data on the Reaction of Urea-Phenol-Hypochlorite in Acidic Solutions

Abstract

The reaction of the Urea-Hypochlorite and Phenol in acidic solutions was studied spectrophotometrically. Reaction rate constants for the decomposition of NH₂Cl in acidic solution and for the formation of the yellow indophenol are given, and the influence of the Urea and Phenol concentrations on the reaction rate constants is described. Kinetic data of interest to the analysts for the above reaction are presented.     

Novel Photosensitive Polymer: Synthesis,Characterization and Thermal Properties of Polymer having Pendant Photocrosslinkable Group

New methacrylic monomer having free radical polymerizable methacryloyl group and photocrosslinkable functional group was synthesized by reacting hydroxyl chalcone with methacryloyl chloride. The monomer was homopolymerized in methyl ethyl ketone solvent using benzoyl peroxide as an initiator at 70°C. The prepared homopolymer was characterized by UV, FT‐IR, ¹H‐NMR and ¹³C‐NMR spectra. The molecular weights (M_w and M_n) were estimated by gel permeation chromatography. The thermal stability of the polymer was measured by thermogravimetric analysis. The glass transition temperature of the polymer was determined by differential scanning calorimetry. The photocrosslinking property of the polymer was also studied.     

Reaction of Thiols and Bisulfite with the Pendant Allyl Groups in Polytriallylamine

The infrared spectrum of polytriallylamine prepared by the free-radical-initiated polymerization of triallylamine indicates the presence of a substantial amount of unsaturation. The usual quantitative methods of determining unsaturation (e. g., bromide/ bromate and mercuric acetate) cannot be used on polytriallylamine because of interference from the amino group. On the other hand, bisulfite was found to react rapidly and quantitatively with the pendant allyl groups of polytriallylamine. The reaction was studied over the pH range 4 to 10 and was fastest at pH 5.2. The reaction is a free-radical reaction which is catalyzed by metal ions and oxygen. The sulfonic acid groups which result from attack of bisulfite on the pendant allyl groups of polytriallylamine form strong zwitterion structures with the amine nitrogens. The addition of thiols is also a free-radical reaction. The reaction of HSCH₂CH₂OH, HSCH₂CO₂H, CH₃SH, H₂S, HSCH₂CH₂N(C₂H₅)₂, CH₅COSH, and C₆H₅SH with polytriallylamine was studied. Of these compounds, only HSCH₂CH₂OH and HSCH₂CO₂H reacted quantitatively. Some reasons for the differences in reactivity are presented.     

Comparison of the Surface Dilational Properties of Block Copolymers and Sodium Oleate Using the Oscillating Bubble Method

The surface dilational modulus of the star-like block copolymer AP432 and linear block copolymer L64 was studied using the oscillating bubble method at an accessible frequency range of 0.05 to 2 Hz, which was compared with anionic surfactant sodium oleate (C₁₇H₃₃COONa) and the influence of inorganic salt NaNO₃ on the surface dilational modulus of AP432 and L64 was also studied. The results indicate that for AP432 and L64 the dilational modulus varies slightly, just decrease gradually with concentrations increasing and never reaches high values with the dilational frequency increasing, but the dilational modulus of C₁₇H₃₃COONa increases gradually with the increase of dilational frequency and pass through the maximum values with increasing concentration. The properties of AP432, L64, and C₁₇H₃₃COONa at the air/water interface were also observed by surface tension measurement. Based on these experimental results, a simple possible adsorption model of these molecules at air/water interface is proposed.     

Dimensions and Orientation of Triton X-100 Micelles in Aqueous Solutions,According to Turbidimetric Data

Russian Journal of Physical Chemistry A - The size and orientation of micelles of nonionic surfactant Triton X-100 in aqueous solutions is determined turbidimetrically. It is shown that micelles...     

Microbial Fuel Cells: The Effects of Configurations,Electrolyte Solutions,and Electrode Materials on Power Generation

This objective of this study is to conduct a systematic investigation of the effects of configurations, electrolyte solutions, and electrode materials on the performance of microbial fuel cells (MFC). A comparison of voltage generation, power density, and acclimation period of electrogenic bacteria was performed for a variety of MFCs. In terms of MFC configuration, membrane-less two-chamber MFCs (ML-2CMFC) had lower internal resistance, shorter acclimation period, and higher voltage generation than the conventional two-chamber MFCs (2CMFC). In terms of anode solutions (as electron donors), the two-chamber MFCs fed with anaerobic treated wastewater (AF-2CMFCs) had the power density 19 times as the two-chamber MFCs fed with acetate (NO₃ ⁻2CMFCs). In terms of cathode solutions (as electron acceptors), AF-2CMFCs with ferricyanide had higher voltage generation than that of ML-2CMFCs with nitrate (NO₃ ⁻ML-2CMFCs). In terms of electrode materials, ML-2CMFCs with granular-activated carbon as the electrode (GAC-ML-2CMFCs) had a power density 2.5 times as ML-2CMFCs with carbon cloth as the electrode. GAC-ML-2CMFCs had the highest columbic efficiency and power output among all the MFCs tested, indicating that the high surface area of GAC facilitate the biofilm formation, accelerate the degradation of organic substrates, and improve power generation.     

Ionic Liquids in Polyethylene Glycol Aqueous Solutions: Salting-in and Salting-out Effects

Summary. Changes of the fluid phase behaviour of polyethylene glycol (PEG) aqueous solutions – viz. critical solution temperature shifts at atmospheric pressure – were produced by the addition of different ionic liquids, namely 1-ethyl-3-methylimidazolium ethyl sulfate and 1-alkyl-3-methylimidazolium chloride (alkyl = ethyl to decyl). The addition of ionic liquids with long alkyl chains improves the solubility of PEG in water (salting-in effect), whereas the impact of short-chain ionic liquids is usually the contrary (salting-out effect). The results are interpreted taking into account the kosmotropic (water-structuring) or chaotropic (water-structure-breaking) nature of ionic liquids, as compared to other inorganic salts.     

Ionic Liquids in Polyethylene Glycol Aqueous Solutions: Salting-in and Salting-out Effects

Changes of the fluid phase behaviour of polyethylene glycol (PEG) aqueous solutions – viz. critical solution temperature shifts at atmospheric pressure – were produced by the addition of different ionic liquids, namely 1-ethyl-3-methylimidazolium ethyl sulfate and 1-alkyl-3-methylimidazolium chloride (alkyl = ethyl to decyl). The addition of ionic liquids with long alkyl chains improves the solubility of PEG in water (salting-in effect), whereas the impact of short-chain ionic liquids is usually the contrary (salting-out effect). The results are interpreted taking into account the kosmotropic (water-structuring) or chaotropic (water-structure-breaking) nature of ionic liquids, as compared to other inorganic salts.     

Formation of the Structure of Aqueous Solutions of Manganese,Nickel, Copper,and Zinc Chlorides,According to X-ray Diffraction Data

Russian Journal of Physical Chemistry A - The structure formation in the aqueous solutions of manganese, nickel, copper, and zinc chlorides is studied via X-ray diffraction in a broad range of...     

Copper-Selective Electrode in the Analysis of Dye-Containing Solutions

The effect of dye concentrations in solutions on the potential of a copper-selective electrode with a chalcogenide membrane was studied. It was found that the electrode potential depends on the dye concentration in solutions containing no copper ions. Conventional selectivity coefficients of the electrode with respect to dye anions were determined. The selectivity coefficients ambiguously changed with the dye nature and their concentration in solutions. The use of the calibration graph method without taking into account the composition of the test solution gave rise to great errors in the results of determinations.     

The Dissolution of Polyols in Salt Solutions and Ionic Liquids at Molecular Level: Ions,Counter Ions,and Hofmeister Effects

The dissolving process of polyols in salt solutions (TBAF, TBAC, TBAB, TBAI, TMAF) and imidazolium-based ionic liquids ([C₂mim][OAc], [C₂mim][Et₂PO₄], [C₂mim][EtSO₄], [C₂mim][SCN]) is exemplarily studied by IR spectroscopy. Vibrational bands and their shifts in the OH stretch region reveal crucial information for the dissolved polyol interacting with the anions of the salt solutions and ionic liquids. The well-chosen set of ionic solutions confirms the linear relation between the OH-stretch frequencies and the solubility capacity of the salt solutions. Likewise, it also provides an explanation of the dissolving process at molecular level. Notably, the solubility capacities of the anions in the salt solutions follow the well-known Hofmeister series. This phenomenon can be understood on the basis of the disruption power of the anions and the specific size ratio of the anion/cation combinations.