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Record W2075894924 · doi:10.1063/1.1485960

Localized relaxation in a glass and the minimum in its orientational polarization contribution

2002· article· en· W2075894924 on OpenAlexaff
G. P. Johari, G. Power, J. K. Vij

Bibliographic record

VenueThe Journal of Chemical Physics · 2002
Typearticle
Languageen
FieldMaterials Science
TopicMaterial Dynamics and Properties
Canadian institutionsMcMaster University
FundersTrinity College DublinEnterprise Ireland
KeywordsDielectricRelaxation (psychology)ThermodynamicsCole–Cole equationPermittivityAnnealing (glass)ChemistryCondensed matter physicsDielectric lossSpectral lineMaterials scienceAnalytical Chemistry (journal)PhysicsQuantum mechanics

Abstract

fetched live from OpenAlex

The dielectric permittivity and loss spectra of the glassy state of 5-methyl-2-hexanol obtained by quenching it from the liquid state has been studied. In one experiment, the spectra were studied at different temperatures as the quenched sample was heated at 0.1 K/min from 105.3 to 160.5 K. In the second experiment, the quenched sample was heated from 77 to 131.6 K and kept at that temperature for 14.6 ks. The relaxation rate, fm,β, the dielectric relaxation strength, Δεβ, and the distribution of relaxation time parameters, α and β, for the Johari–Goldstein process were determined. The parameter β was found to be equal to 1 and independent of both the temperature and time, Δεβ initially decreased on increasing the temperature, reached a minimum value at ∼145.6 K, and then increased. The plot of fm,β against the reciprocal temperature decreased in slope and at ∼140 K became linear. This indicates that fm,β increases on structural relaxation. In the course of the annealing at 131.6 K, Δεβ of the quenched sample decreased with time, approaching a plateau value. It is described by an equation, Δεβ(t)=Δεβ(t→∞)+[Δεβ(t=0)−Δεβ(t→∞)]exp[−(t/τ)], where t is the time, and τ (=3.5 ks) is the characteristic time. It is pointed out that contrary to the earlier finding, o-terphenyl shows a β relaxation in the equilibrium liquid state. A consideration of dielectric permittivity arising from small-angle motions of all molecules, which has been suggested as an alternative mechanism for the localized motions seen as β relaxation, indicates that this mechanism is inconsistent with the known increase in the equilibrium permittivity on cooling.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Bench or experimental · Consensus signal: Bench or experimental
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.001
Threshold uncertainty score0.002

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0010.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.011
GPT teacher head0.219
Teacher spread0.208 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designBench or experimental
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations36
Published2002
Admission routes1
Has abstractyes

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