196,783 research outputs found
Characterization of a 17-4 PH stainless steel obtained through metal powder Hot Isostatic Pressing process for automotive application
Get PDFSynthesis of photochromic compounds for aqueous solutions and focusable light.
Get PDFPhotochromic compounds with improved performance in pure water have been prepared and characterized. They possess an asymmetrical and extended conjugation system with a 1,2-bis(3-thienyl)perfluorocyclopentene core, additional thiophene rings connected with sulfonic acid residues, as well as terminal pyrid-4-yl and 4-alkoxyphenyl groups. A multistep synthetic route to a key compound with an amino group required for further derivatization has been developed. The complete photocyclization reaction of the initial "open ring" compound (with absorption maximum at 340 nm in MeOH or water) can be performed with a diode laser in pure water or aqueous buffer solutions (without added or-ganic solvents) under irradiation at 366-375 nm, and the reverse ring-opening reaction of the colored "closed ring" compound (λmax = 628 or 624 nm in MeOH or water) takes place under irradiation with visible green or red light (>500 nm). Building block 57, with a secondary amino group, can further be used in the synthesis of practically important, reversibly switchable, fluorescent compounds in which the fluorescent dye (donor) is attached to a photochromic unit (acceptor), and the resonant energy transfer from a donor to the colored form of an acceptor provides a reversible quenching of the fluorescence signal in aqueous solutions. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.Fil: Polyakova, Svetlana M.. Max Planck Institute for Biophysical Chemistry; Alemania. Institute of Organic Chemistry and Biochemistry; AlemaniaFil: Belov, Vladimir N.. Max Planck Institute for Biophysical Chemistry; AlemaniaFil: Bossi, Mariano Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Max Planck Institute for Biophysical Chemistry; AlemaniaFil: Hell, Stefan W.. Max Planck Institute for Biophysical Chemistry; Alemani
Modern approaches for study of eutectoid steel oxidation and decarburization
No full textThis paper describes the results of a laboratory study into the high-temperature surface oxidation and decarburization of eutectoid steel performed using thermal gravimetric analysis which makes it possible to understand the steel surface oxidation kinetics in non-isothermal conditions as the steel specimen is continuously heated to a specified temperature. An exponential relationship is obtained between the heating temperature and the iron loss in steel. A relationship is established between the heating temperature applied and the surface oxidation rate observed in a eutectoid steel specimen. It is shown that when the temperature of the specimen is raised from 900 to 1000°С, it leads to a triple increase in the surface oxidation rate, whereas the temperature increase to 1200°С results in an eightfold increase in the surface oxidation rate. It is noted that, within the temperature range of 720-950°С, the phase transformations observed are accompanied with intensified scale formation and surface carbon depletion. Using the emission spectrometry technique, the concentration of carbon is determined in the surface layer in relation to the heating temperature and time. The results obtained indicate that eutectoid steel is subjected to an intense surface decarburization at the temperatures of 600-1200°С
The Use the Concept of Multiscale Simulation to Improve the Topology of TRIP-Steel Parts Operating Under Extreme Loads
No full textMechanical properties of prestressing strands and how they tend to change under thermo-mechanical treatment
No full textThis paper examines the mechanical properties of high-strength (1,770 MPa) 7-wire prestressing strands and how they tend to change under thermo-mechanical treatment involving short-term induction tempering under high tension. The change dynamics of the following properties was monitored for 12.5 mm strands: tensile strength, yield strength, full elongation at maximum tension force and modulus of elasticity in the temperature range from 360 to 400 °С, the process speed range from 50 to 65 m/min, and at the tension force of 64 kN. The authors found a quantitative increase of the mechanical properties of prestressing strands for all the studied regimes of thermo-mechanical treatment. Thermo-mechanical treatment resulted in a significant growth in yield strength — from 28 to 36%, and in full elongation at maximum tension force, which demonstrated a higher than double growth. The paper shows how the temperature and rate of thermo-mechanical processing influence the mechanical properties of prestressing strands and their change dynamics
Features of manifestation of fears and anxiety in children with early childhood autism
Get PDFThe Youth of the 21st Century: Education, Science, Innovations : Proceedings of VI International Conference for Students, Postgraduates and Young Scientists, Vitebsk, December 12, 2019. - Vitebsk : Vitebsk State University named after P. M. Masherov, 2019. - P. 385-387.- Bibliogr.: p. 387 (3 nam.)
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
Effect of intercritical annealing and austempering on the microstructure and mechanical properties of a high silicon manganese steel
Get PDFHigh Silicon Austempered steels (AHSS) are materials of great interest due to their excellent combination of high strength, ductility, toughness, and limited costs. These steel grades are characterized by a microstructure consisting of ferrite and bainite, accompanied by a high quantity retained austenite (RA). The aim of this study is to analyze the effect of an innovative heat treatment, consisting of intercritical annealing at 780 °C and austempering at 400 °C for 30 minutes, on the microstructure and mechanical properties of a novel high silicon steel (0.43C-3.26Si-2.72Mn wt.%). The microstructure was characterized by optical and electron microscopy and XRD analysis. Hardness and tensile tests were performed. A multiphase ferritic-martensitic microstructure was obtained. A hardness of 426 HV and a tensile strength of 1650 MPa were measured, with an elongation of 4.5%. The results were compared with those ones obtained with annealing and Q&T treatments
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Replication data for: Risk Perceptions and Private Protective Behaviors: Evidence from COVID-19 Pandemic
No full textReview of Economics and Statistics: Forthcomin
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