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Record W1968750063 · doi:10.1080/00150190214282

EPR and Uniaxial Pressure Measurements of the Phase Transition in (NH 4 ) 2 SO 4 Crystal

2002· article· en· W1968750063 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.

Bibliographic record

VenueFerroelectrics · 2002
Typearticle
Languageen
FieldMaterials Science
TopicSolid-state spectroscopy and crystallography
Canadian institutionsYork University
Fundersnot available
KeywordsMaterials sciencePhase transitionFerroelectricityAnisotropyHydrostatic pressureElectron paramagnetic resonancePhase (matter)Crystal (programming language)DielectricCondensed matter physicsCrystallographyAnalytical Chemistry (journal)Nuclear magnetic resonanceThermodynamicsChemistryPhysicsOptics

Abstract

fetched live from OpenAlex

The uniaxial-pressure dependence of the phase transition temperature in (NH 4 ) 2 SO 4 was measured for the first time along the three crystal axes. The splitting of EPR lines caused by the structure change was taken as signature indicating T c temperature. The phase transition temperature is shifted by the uniaxial pressure along a , b , and c axes at the linear rate dT c / dX a = ( m 9.5 - 0.2) K/kbar, dT c / dX b = (0.0 - 0.2) K/kbar, dT c / dX c = (5.3 - 0.2) K/kba, respectively. The values of the three rates are consistant with the hydrostatic pressure measurements of dT c / dp and confirm the reliability of the uniaxial-stress measurements. Large anisotropy of the uniaxial pressure coefficients dT c / dX i together with the temperature dependence of the EPR lines in the paraelectric and ferroelectric phase is discussed in terms of previously proposed models of the mechanism of the phase transition. The driving force of the phase transition is related to the dynamics of SO 4 -NH 4 (I) groups. Below T c , NH 4 (I) groups become ordered and their orientation is fixed, while NH 4 (II) groups gradually change their orientation. Keywords: Ammonium Sulfate(NH 4 ) 2 SO 4EprUniaxial PressurePhase TransitionFerroelectric

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.

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation 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 score0.019
Threshold uncertainty score0.386

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.001
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

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 head0.025
GPT teacher head0.256
Teacher spread0.231 · 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