Correlation Of Thermal Stability Research Articles

Investigating the Applicability and Limitations of Glass-Forming Criteria Based on Bond Parameters on Thermal Stability in Mg-Based Multicomponent Bulk Metallic Glasses

In this paper, correlation of thermal stability ( $$ \Delta {T_x} $$ ) with the bond parameters such as electronegativity ( $$ \Delta x $$ ), atomic radius mismatch ( $$ \delta $$ ), and valence electron concentration ( $$ \Delta {n^{1/3}} $$ ) for Mg-based multicomponent bulk metallic glasses (BMGs) have been evaluated. A statistical approach of regression analysis has been adopted to investigate correlations among these parameters. Available experimental data have been used for the systematic investigation from ternary to multicomponent Mg-based BMGs. In addition, the applicability of the criteria has been assessed for the systems with and without rare earth (RE) elements. We have found that BMG systems containing RE group elements have significant effect on width of supercooled liquid region. Results obtained from our modified empirical equation have been compared with that of earlier models and have shown better correlations.

Correlation of Thermal Stability and Structural Distortion of DNA Interstrand Cross-Links Produced from Oxidized Abasic Sites with Their Selective Formation and Repair.

C4'-oxidized (C4-AP) and C5'-oxidized abasic sites (DOB) that are produced following abstraction of a hydrogen atom from the DNA backbone reversibly form cross-links selectively with dA opposite a 3'-adjacent nucleotide, despite the comparable proximity of an opposing dA. A previous report on UvrABC incision of DNA substrates containing stabilized analogues of the ICLs derived from C4-AP and DOB also indicated that the latter is repaired more readily by nucleotide excision repair [Ghosh, S., and Greenberg, M. M. (2014) Biochemistry 53, 5958-5965]. The source for selective cross-link formation was probed by comparing the reactivity of ICL analogues of C4-AP and DOB that mimic the preferred and disfavored cross-links with that of reagents that indirectly detect distortion by reacting with the nucleobases. The disfavored C4-AP and DOB analogues were each more reactive than the corresponding preferred cross-link substrates, suggesting that the latter are more stable, which is consistent with selective ICL formation. In addition, the preferred DOB analogue is more reactive than the respective C4-AP ICL, which is consistent with its more efficient incision by UvrABC. The conclusions drawn from the chemical probing experiments are corroborated by UV melting studies. The preferred ICLs exhibit melting temperatures higher than those of the corresponding disfavored isomers. These studies suggest that oxidized abasic sites form reversible interstrand cross-links with dA opposite the 3'-adjacent thymidine because these products are more stable and the thermodynamic preference is reflected in the transition states for their formation.

Correlation of thermal stability and anisotropy distribution in data storage tapes prepared from ultrafine particles

The correlation between thermal stability and anisotropy field (H/sub A/) distribution was studied for data storage tapes prepared from ultrafine metal particulate (MP) composition and Ba-ferrite particles. At low temperature, the thermal effect had no influence in either tape. H/sub A/ distributions in easy direction of both tapes were excellent at 77 K. The angular distribution of H/sub A/was sharp in the case of MP tape, whereas the easy axes were widely distributed in the case of Ba-ferrite tape. In the easy direction, a proportion of particles had low anisotropy values in both tapes at 350 K. The normalized magnetization decay of MP and Ba-ferrite tapes in a -0.5 kOe field at 350 K was 0.4 and 1.4%/decade, respectively, and the respective thermal stability factors were 81 and 49. The magnetization stability is essentially determined by the magnitude and angular distribution of H/sub A/.

Correlation of thermal stability with structural properties of ultrathin single-walled carbon nanotubes

Based on quantum chemical calculations, we have established the relationship between the thermal stability and structural properties of ultrathin single-walled carbon nanotubes (SWCNTs). Our results on the heat of formation as a function of tube diameter predict a lower limit of 0.341 nm in diameter for experimentally observable SWCNTs. The absence of any distinctive minimum points on the heat of formation curve implies the experimental difficulties in obtaining uniform tubes. A detailed correlation between their curvature and chemical bonding properties was obtained for both the zigzag and armchair conformations.

Correlation of thermal stability and signal-to-noise ratio of thin film recording media

The thermal stability of data stored in thin film recording media is closely tied to signal-to-noise ratio (SNR), yet is not correlated in a simple way. Indeed grain size strongly affects both SNR and thermal stability, but macroscopic magnetic properties as well as recording conditions are equally influential. This is illustrated by measurements of SNR and signal thermal decay along with a simple model analysis. Dependence of areal density on key magnetic properties, under SNR and stability constraints, is formulated.

Thermal stability of transition-metal complexes

This review aims at justifying the relationship between the room-temperature structures of transition-metal complexes and their thermal stabilities. The different factors affecting the thermal stability were also clarified. The survey of a larger number of transition-metal complexes showed various correlations of thermal stability with metal ion, ligand character or counterion.

Correlation of thermal stability with structures for some metal complexes

Thermogravimetric studies have been carried out for a number of complexes of the type MCu(dtc) 4[dtc = N-ethylcyclohexyldithiocarbamate (I); M = Zn(II), Cd(II), Hg(II)], (η 5-C 5H 5) 2M'Cl(L)(II) [L = benzylpenicillin; M' = Ti(IV), Zr(IV)] and [(η 5-R) 2M'L'] + [dtz] −(III) [HL' = oxine; dtz - phenyldithiocarbazate (C 6H 5NHNHCS 2); R = cyclopentadienyl (C 5H 5), indenyl (C 9H 7)]. From TG curves, the order and apparent activation energy for the thermal decomposition reaction have been elucidated, and the various thermal stabilities have been correlated with some structural aspects of the complexes concerned. ▪