Quenching

About: Quenching is a research topic. Over the lifetime, 22899 publications have been published within this topic receiving 224316 citations.

Phase transformations in metals and alloys

Abstract: Thermodynamics and Phase Diagrams Equilibrium Single-Component Systems Binary Solutions Equilibrium in Heterogeneous Systems Binary Phase Diagrams Influence of Interfaces on Equilibrium Ternary Equilibrium Additional Thermodynamic Relationships for Binary Solutions Computation of Phase Diagrams Kinetics of Phase Transformations Exercises References Further Readings Diffusion Atomic Mechanisms of Diffusion Interstitial Diffusion Substitutional Diffusion Atomic Mobility Tracer Diffusion in Binary Alloys Diffusion in Ternary Alloys High-Diffusivity Paths Diffusion in Multiphase Binary Systems Exercises References Further Readings Crystal Interfaces and Microstructure Interfacial Free Energy Solid=Vapor Interfaces Boundaries in Single-Phase Solids Interphase Interfaces in Solids Interface Migration Exercises References Further Readings Solidification Nucleation in Pure Metals Growth of a Pure Solid Alloy Solidification Solidification of Ingots and Castings Solidification of Fusion Welds Solidification during Quenching from the Melt Metallic Glasses Case Studies of Some Practical Castings and Welds Exercises References Further Readings Diffusional Transformations in Solids Homogeneous Nucleation in Solids Heterogeneous Nucleation Precipitate Growth5 Overall Transformation Kinetics-TTT Diagrams Precipitation in Age-Hardening Alloys Precipitation of Ferrite from Austenite Cellular Precipitation Eutectoid Transformations Massive Transformations Ordering Transformations Case Studies Exercises References Further Readings Diffusionless Transformations Characteristics of Diffusionless Transformations Martensite Crystallography Theories of Martensite Nucleation Martensite Growth1 Premartensite Phenomena Tempering of Ferrous Martensites Case Studies Exercises References Further Readings Solutions to Exercises Compiled by John C. Ion

Quenching of fluorescence by oxygen. A probe for structural fluctuations in macromolecules.

Abstract: Quenching of the fluorescence of various fluorophores by molecular oxygen has been studied in aqueous and nonaqueous solutions equilibrated with oxygen pressures up to 100 atm. Temperature dependence of quenching, agreement with the Stern–Volmer equation, and fluorescence lifetime measurements indicate that essentially all the observed quenching is dynamic and close to the diffusion-controlled limits. Studies of charged polyamino acids containing tryptophan show that oxygen quenching, in contrast to I−, is completely insensitive to charge effects. Ethidium bromide, when intercalated into double helical DNA, is quenched with 1/30th of the efficiency of the free dye in solution. Three dyes bound to bovine serum albumin were also found to be relatively protected from the free diffusion of oxygen. Quenching of intrinsic or bound fluorophores by molecular oxygen is therefore an appropriate method to determine the accessibility to oxygen of regions of the macromolecule surrounding the fluorophore and indirectly the structural fluctuations in the macromolecule that permit its diffusion to the fluorophore.

Low compressibility carbon nitrides

Abstract: A cubic form of C3N4 with a zero-pressure bulk modulus exceeding that of diamond Also a process for preparing such product which comprises combining carbon and nitrogen at a pressure of 120,000 to 800,000 atmosphere and a temperature of 1000-3000 °C Carbon particles may be immersed in liquid nitrogen and the mixture heated by a laser beam followed by quenching

Transition metals in silicon

Abstract: A review is given on the diffusion, solubility and electrical activity of 3d transition metals in silicon. Transition elements (especially, Cr, Mn, Fe, Co, Ni, and Cu) diffuse interstitially and stay in the interstitial site in thermal equilibrium at the diffusion temperature. The parameters of the liquidus curves are identical for the Si:Ti — Si:Ni melts, indicating comparable silicon-metal interaction for all these elements. Only Cr, Mn, and Fe could be identified in undisturbed interstitial sites after quenching, the others precipitated or formed complexes. The 3d elements can be divided into two groups according to the respective enthalpy of formation of the solid solution. The distinction can arise from different charge states of these impurities at the diffusion temperature. For the interstitial 3d atoms remaining after quenching, reliable energy levels are established from the literature and compared with recent calculations.