Bubbles in liquids, soft and squeezy objects made of gas and vapour, yet so strong as to destroy any material and so mysterious as at times turning into tiny light bulbs, are the topic of the present report. Bubbles respond to pressure forces and reveal their full potential when periodically driven by sound waves. The basic equations for nonlinear bubble oscillation in sound fields are given, together with a survey of typical solutions. A bubble in a liquid can be considered as a representative example from nonlinear dynamical systems theory with its resonances, multiple attractors with their basins, bifurcations to chaos and not yet fully describable behaviour due to infinite complexity. Three stability conditions are treated for stable trapping of bubbles in standing sound fields: positional, spherical and diffusional stability. Chemical reactions may become important in that respect, when reacting gases fill the bubble, but the chemistry of bubbles is just touched upon and is beyond the scope of the present report. Bubble collapse, the runaway shrinking of a bubble, is presented in its current state of knowledge. Pressures and temperatures that are reached at this occasion are discussed, as well as the light emission in the form of short flashes. Aspherical bubble collapse, as for instance enforced by boundaries nearby, mitigates most of the phenomena encountered in spherical collapse, but introduces a new effect: jet formation, the self-piercing of a bubble with a high velocity liquid jet. Examples of this phenomenon are given from light induced bubbles. Two oscillating bubbles attract or repel each other, depending on their oscillations and their distance. Upon approaching, attraction may change to repulsion and vice versa. When being close, they also shoot self-piercing jets at each other. Systems of bubbles are treated as they appear after shock wave passage through a liquid and with their branched filaments that they attain in standing sound fields. The N-bubble problem is formulated in the spirit of the n-body problem of astrophysics, but with more complicated interaction forces. Simulations are compared with three-dimensional bubble dynamics obtained by stereoscopic high speed digital videography.

Physics of bubble oscillations

Anions of sodium, potassium, rubidium, and cesium are stable both in suitable solvents and in crystalline solids. The latter can be prepared either by cooling a saturated solution or by rapid solvent evaporation. Thermodynamic arguments show that alkali metal anions can probably exist in saturated solutions of the alkali metals in any compatible solvent, but that below saturation, dissociation into the cation and solvated electrons is favored in highly polar solvents such as ammonia. The key to solvent-free salts of the alkali metal anions is stabilization of the cation by incorporation into a suitable crown or cryptand complex. By using such complexes it also appears possible to produce “electride” salts in which the charge of the complexed cation is balanced by a trapped electron. The chemical, electrical, and optical properties of salts of the alkali metal anions and “electrides” could provide useful applications.

Compounds of Alkali Metal Anions

The radiation chemistry of metal ions in aqueous solution

The selective eletron-transfer quenching of the radical anions of dicyanoanthracene, phenazine, and anthraquinones in the excited state by a quencher such as fumaronitrile or dicyanobenzene is investigated in N,N-dimethylformamide solution at room temperature using the pulse radiolysis−laser flash photolysis combined method. The radical anions generated by pulse radiolysis do not change upon irradiation with a laser flash at 532 nm. The radical anions in the excited state decay into the ground state within the laser flash (5 ns). Lifetimes of approximately 4 ns are estimated for three radical anions in the excited state assuming a diffusion-controlled rate constant for the electron-transfer quenching. The shorter lifetimes of 1.0−1.4 ns for methyl and chloro substituents on anthraquinone are discussed in terms of internal conversion from the excited to the ground state of the radical anions accelerated by rotation of the substituents. The energy gap between the excited and ground states of the radical ani...

Lifetimes of Radical Anions of Dicyanoanthracene, Phenazine, and Anthraquinone in the Excited State from the Selective Electron-Transfer Quenching

— This paper is a critical review of the singlet oxygen oxidation of polymers in solid state and in solution, referring in particular to polydienes, polystyrene and polyvinyl chloride). The singlet oxygenation of polydienes resulted in formation of allylic hydroperoxide groups with shifted double bonds, according to the “ene”-type process. The singlet oxygenation of polystyrene and polyvinyl chloride) occurs only when the new double bonds are formed in these polymers. During dye-photosensitized singlet oxygenation of polydienes in methanol-benzene solution, a very rapid decrease in the molecular weight was observed. For the chain-scission which occurs, not only singlet oxygen but several intermediates such as radicals, bi-radicals and cation-radicals which are formed during light fading of dyes are responsible. At the end of this paper a short review appears which has been focused on the quenching behavior of stabilizers, particularly interactions with singlet oxygen.

The role of singlet oxygen in the photooxidation of polymers

Photoejection of electrons from pyrenide ions (π. - ) or sodium pyrenide ion pairs (π. - , Na + ) was effected in tetrahydrofuran (THF) or tetrahydropyran (THP) solution by flash of light (λ > 420 nm). As the reaction was performed in the presence of a large excess of biphenyl (B) the ejected electrons were captured preferentially by that hydrocarbon reducing it to biphenylide radical ion (B. - or B. - , Na + ). Due to the low concentration of pyrene (π) the subsequent reactions between biphenylide and pyrene, namely B. - + π ( k 1 →) B + π. - (1) and B. - , Na + + π ( k 2 →) B + π. - , Na + , (2) could be easily monitored after the flash. By varying the ratio of [B. - ]/[B. - , Na + ] it was possible to make either (1) or (2) dominant, and hence to determine the rate constants k 1 and k 2 . Thus, k 1 = (4.8 ± 0.5) x 10 10 1 mol -1 s -1 and k 2 = 0.6 x 10 10 1 mol -1 s -1 for the electron transfer in THF, and k 2 = 0.5 x 10 10 1 mol -1 s -1 for the reaction in THP, all the constants referring to ≈ 20 °C.

Kinetics of electron transfer processes involving free ions and ion pairs studied by flash photolysis

Flash photolysis of sodium pyrenide, π· − , Na + , in THF demonstrated that three transients are formed in the process: solvated electrons, e-, their ion pairs with Na+ cations, e~, Na+, and sodium atoms, Na°. The rate constants of the following reactions were determined: e - , Na + + n -» ttT, Na + k 3 = 1.7 x 10 10 1 mol -1 s -1 , (3) e - + ir -> ITT k 4 = 7 x 10 10 1 mol -1 s -1 , (4) Na° + tt -» ttT, Na + k 5 = 1 x 10 10 1 mol -1 s -1 , (5) e - , Na + Na° k 6 = 4 x 10 3 s -1 . (6) The dissociation constant of e - , Na + pair into e - and Na + was estimated to be 0.3 x 10 -7 mol/l in THF at about 20 °C, and the rate constant of association of e - with Na + cations was estimated as 4 x 101 11 mol -1 s -1 .

Capture of solvated electrons and the collapse of solvated electron—sodium cation pair into sodium atom, studied by flash photolysis

Kinetics of electron-transfer and in tetrahydrofuran

Collapse of e−, Na+ pairs into sodium atoms and the reactions of solvated electrons and of e−, Na+ pairs

Studies on the photo-oxidation mechanism of polymers—IX. The photo-sensitized oxidation of cis-1,4-polybutadiene by n-methyl-2-benzoyl-β-naphthiazoline

Popular Tasks used by Researchers

How can I help with your research?

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

We encountered an error while loading the panel. Please try refreshing the page.

Something went wrong

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

Anyone with the link can view this chat. You can switch it back to private anytime.

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Göran Rämme

Author Tools

Chat about Author