The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform
Changheui Jang - One of the best experts on this subject based on the ideXlab platform.
-
low cycle fatigue behaviors of two heats of sa508 gr 1a low alloy steel in 310 c air and Deoxygenated Water effects of dynamic strain aging and microstructures
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2013Co-Authors: Hun Jang, Changheui JangAbstract:Abstract The low cycle fatigue (LCF) resistances of two heats of SA508 Gr.1a low alloy steel, heat FP with a ferrite–pearlite microstructure and heat BA with a bainite microstructure, were compared in 310 °C air and Deoxygenated Water. The LCF life of heat FP was shorter than that of heat BA in 310 °C Deoxygenated Water while the LCF life of both heats was comparable in 310 °C air. Such behaviors were explained considering the dynamic strain aging (DSA) behaviors in both environments and their microstructures. Based on cyclic stress and tensile behaviors, it was found that heat BA showed higher degree of DSA than heat FP in 310 °C air, but both showed similar degree of DSA in 310 °C Deoxygenated Water because the degree of DSA was reduced by absorbed hydrogen. In case of microstructure, heat FP had a lower fatigue cracking resistance due to the stress concentration effect in ferrite–pearlite interface. As a result, in 310 °C air, where the effect of DSA was large enough to override the microstructure effect, LCF life of heat BA was similar to that of heat FP. On the other hand, LCF life of heat BA was longer than that of heat FP in 310 °C Deoxygenated Water, where the effect of DSA was not so significant.
-
Low-cycle fatigue behaviors of two heats of SA508 Gr.1a low alloy steel in 310 °C air and Deoxygenated Water—Effects of dynamic strain aging and microstructures
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2013Co-Authors: Hun Jang, Changheui JangAbstract:Abstract The low cycle fatigue (LCF) resistances of two heats of SA508 Gr.1a low alloy steel, heat FP with a ferrite–pearlite microstructure and heat BA with a bainite microstructure, were compared in 310 °C air and Deoxygenated Water. The LCF life of heat FP was shorter than that of heat BA in 310 °C Deoxygenated Water while the LCF life of both heats was comparable in 310 °C air. Such behaviors were explained considering the dynamic strain aging (DSA) behaviors in both environments and their microstructures. Based on cyclic stress and tensile behaviors, it was found that heat BA showed higher degree of DSA than heat FP in 310 °C air, but both showed similar degree of DSA in 310 °C Deoxygenated Water because the degree of DSA was reduced by absorbed hydrogen. In case of microstructure, heat FP had a lower fatigue cracking resistance due to the stress concentration effect in ferrite–pearlite interface. As a result, in 310 °C air, where the effect of DSA was large enough to override the microstructure effect, LCF life of heat BA was similar to that of heat FP. On the other hand, LCF life of heat BA was longer than that of heat FP in 310 °C Deoxygenated Water, where the effect of DSA was not so significant.
-
effect of cyclic strain rate and sulfides on environmentally assisted cracking behaviors of sa508 gr 1a low alloy steel in Deoxygenated Water at 310
Nuclear Engineering and Technology, 2008Co-Authors: Hun Jang, Changheui Jang, Chan Kook MoonAbstract:Korea Hydro and Nuclear Power Co., Ltd. The Second Phase BK21 Program of the Ministry of Education, Science and Technology of Korea.
-
effect of cyclic strain rate on environmental fatigue behaviors of sa508 gr 1a low alloy steel in 310 c Deoxygenated Water
Advanced Materials Research, 2007Co-Authors: Hun Jang, Changheui JangAbstract:The low cycle fatigue tests of SA508 Gr.1a low alloy steel in 310oC Deoxygenated Water were conducted to investigate the effect of cyclic strain rate on the environmentally assisted cracking (EAC) mechanisms. The flattened striations and the blunt crack tip, which indicate the occurrence of the slip dissolution/oxidation, were mainly observed for the specimen tested at 0.008 %/s. On the other hand, the brittle cracks and the blunt main crack with microcracks, which are the evidences of the hydrogen-induced cracking (HIC), were observed for the specimens tested at 0.04 and 0.4 %/s. Through this study, it is thought that the slip dissolution/oxidation dominantly contributes to the reduction in the fatigue life at a strain rate of 0.008 %/s and the HIC is mainly responsible for the reduction in the fatigue life at strain rates of 0.04 and 0.4 %/s.
-
Effect of Cyclic Strain Rate on Environmental Fatigue Behaviors of SA508 Gr.1a Low Alloy Steel in 310°C Deoxygenated Water
Advanced Materials Research, 2007Co-Authors: Hun Jang, Changheui JangAbstract:The low cycle fatigue tests of SA508 Gr.1a low alloy steel in 310oC Deoxygenated Water were conducted to investigate the effect of cyclic strain rate on the environmentally assisted cracking (EAC) mechanisms. The flattened striations and the blunt crack tip, which indicate the occurrence of the slip dissolution/oxidation, were mainly observed for the specimen tested at 0.008 %/s. On the other hand, the brittle cracks and the blunt main crack with microcracks, which are the evidences of the hydrogen-induced cracking (HIC), were observed for the specimens tested at 0.04 and 0.4 %/s. Through this study, it is thought that the slip dissolution/oxidation dominantly contributes to the reduction in the fatigue life at a strain rate of 0.008 %/s and the HIC is mainly responsible for the reduction in the fatigue life at strain rates of 0.04 and 0.4 %/s.
Hun Jang - One of the best experts on this subject based on the ideXlab platform.
-
low cycle fatigue behaviors of two heats of sa508 gr 1a low alloy steel in 310 c air and Deoxygenated Water effects of dynamic strain aging and microstructures
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2013Co-Authors: Hun Jang, Changheui JangAbstract:Abstract The low cycle fatigue (LCF) resistances of two heats of SA508 Gr.1a low alloy steel, heat FP with a ferrite–pearlite microstructure and heat BA with a bainite microstructure, were compared in 310 °C air and Deoxygenated Water. The LCF life of heat FP was shorter than that of heat BA in 310 °C Deoxygenated Water while the LCF life of both heats was comparable in 310 °C air. Such behaviors were explained considering the dynamic strain aging (DSA) behaviors in both environments and their microstructures. Based on cyclic stress and tensile behaviors, it was found that heat BA showed higher degree of DSA than heat FP in 310 °C air, but both showed similar degree of DSA in 310 °C Deoxygenated Water because the degree of DSA was reduced by absorbed hydrogen. In case of microstructure, heat FP had a lower fatigue cracking resistance due to the stress concentration effect in ferrite–pearlite interface. As a result, in 310 °C air, where the effect of DSA was large enough to override the microstructure effect, LCF life of heat BA was similar to that of heat FP. On the other hand, LCF life of heat BA was longer than that of heat FP in 310 °C Deoxygenated Water, where the effect of DSA was not so significant.
-
Low-cycle fatigue behaviors of two heats of SA508 Gr.1a low alloy steel in 310 °C air and Deoxygenated Water—Effects of dynamic strain aging and microstructures
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2013Co-Authors: Hun Jang, Changheui JangAbstract:Abstract The low cycle fatigue (LCF) resistances of two heats of SA508 Gr.1a low alloy steel, heat FP with a ferrite–pearlite microstructure and heat BA with a bainite microstructure, were compared in 310 °C air and Deoxygenated Water. The LCF life of heat FP was shorter than that of heat BA in 310 °C Deoxygenated Water while the LCF life of both heats was comparable in 310 °C air. Such behaviors were explained considering the dynamic strain aging (DSA) behaviors in both environments and their microstructures. Based on cyclic stress and tensile behaviors, it was found that heat BA showed higher degree of DSA than heat FP in 310 °C air, but both showed similar degree of DSA in 310 °C Deoxygenated Water because the degree of DSA was reduced by absorbed hydrogen. In case of microstructure, heat FP had a lower fatigue cracking resistance due to the stress concentration effect in ferrite–pearlite interface. As a result, in 310 °C air, where the effect of DSA was large enough to override the microstructure effect, LCF life of heat BA was similar to that of heat FP. On the other hand, LCF life of heat BA was longer than that of heat FP in 310 °C Deoxygenated Water, where the effect of DSA was not so significant.
-
effect of cyclic strain rate and sulfides on environmentally assisted cracking behaviors of sa508 gr 1a low alloy steel in Deoxygenated Water at 310
Nuclear Engineering and Technology, 2008Co-Authors: Hun Jang, Changheui Jang, Chan Kook MoonAbstract:Korea Hydro and Nuclear Power Co., Ltd. The Second Phase BK21 Program of the Ministry of Education, Science and Technology of Korea.
-
effect of cyclic strain rate on environmental fatigue behaviors of sa508 gr 1a low alloy steel in 310 c Deoxygenated Water
Advanced Materials Research, 2007Co-Authors: Hun Jang, Changheui JangAbstract:The low cycle fatigue tests of SA508 Gr.1a low alloy steel in 310oC Deoxygenated Water were conducted to investigate the effect of cyclic strain rate on the environmentally assisted cracking (EAC) mechanisms. The flattened striations and the blunt crack tip, which indicate the occurrence of the slip dissolution/oxidation, were mainly observed for the specimen tested at 0.008 %/s. On the other hand, the brittle cracks and the blunt main crack with microcracks, which are the evidences of the hydrogen-induced cracking (HIC), were observed for the specimens tested at 0.04 and 0.4 %/s. Through this study, it is thought that the slip dissolution/oxidation dominantly contributes to the reduction in the fatigue life at a strain rate of 0.008 %/s and the HIC is mainly responsible for the reduction in the fatigue life at strain rates of 0.04 and 0.4 %/s.
-
Effect of Cyclic Strain Rate on Environmental Fatigue Behaviors of SA508 Gr.1a Low Alloy Steel in 310°C Deoxygenated Water
Advanced Materials Research, 2007Co-Authors: Hun Jang, Changheui JangAbstract:The low cycle fatigue tests of SA508 Gr.1a low alloy steel in 310oC Deoxygenated Water were conducted to investigate the effect of cyclic strain rate on the environmentally assisted cracking (EAC) mechanisms. The flattened striations and the blunt crack tip, which indicate the occurrence of the slip dissolution/oxidation, were mainly observed for the specimen tested at 0.008 %/s. On the other hand, the brittle cracks and the blunt main crack with microcracks, which are the evidences of the hydrogen-induced cracking (HIC), were observed for the specimens tested at 0.04 and 0.4 %/s. Through this study, it is thought that the slip dissolution/oxidation dominantly contributes to the reduction in the fatigue life at a strain rate of 0.008 %/s and the HIC is mainly responsible for the reduction in the fatigue life at strain rates of 0.04 and 0.4 %/s.
Brian J. Frost - One of the best experts on this subject based on the ideXlab platform.
-
Isomerization of trans-[Ru(PTA)4Cl2] to cis-[Ru(PTA)4Cl2] in Water and organic solvent: revisiting the chemistry of [Ru(PTA)4Cl2].
Inorganic Chemistry, 2007Co-Authors: Charles A. Mebi, Brian J. FrostAbstract:trans-[Ru(PTA)4Cl2] (trans-1), (PTA = 1,3,5-triaza-7-phosphatricyclo[3.3.1.13,7]decane) has been isolated and structurally characterized by X-ray crystallography. The structure reveals ruthenium in a slightly distorted-octahedral environment bound to two axial chlorides and four equatorial PTA ligands. In organic solvents, trans-1 undergoes a relatively clean isomerization to cis-1. In aqueous environments, trans-1 undergoes a more complicated transformation involving isomerization, protonation, and ligand substitution affording cis-1 and a series of structurally related molecules. From these results, we conclude that the synthesis of [Ru(PTA)4Cl2] (1) affords trans-1, not cis-1, as earlier reports suggest. The Water-soluble hydride cis-[Ru(PTA)4H2] (2) has also been synthesized from the reaction of trans-[Ru(PTA)4Cl2] with excess sodium formate. Compound 2 is stable in Deoxygenated Water and undergoes H/D exchange with D2O (t1/2 ≈ 120 min, at 25 °C). The solid-state structures of both trans-1 and 2 are d...
-
Aqueous Organometallic Chemistry: Synthesis, Structure, and Reactivity of the Water-Soluble Metal Hydride CpRu-(PTA)~2H
Organometallics, 2004Co-Authors: Brian J. Frost, Charles A. MebiAbstract:The reaction of CpRu(PTA)2Cl (1) with KOH in methanol afforded the Water-soluble hydride CpRu(PTA)2H (2) in good yield. The solid-state structures of both CpRu(PTA)2H and the previously reported CpRu(PTA)2Cl are described and exhibit classic piano stool geometries. Complex 2 is one of a very few structurally characterized CpRu(PR3)2H compounds known and the only one that is Water-soluble. The ruthenium hydride is stable and soluble (S25 °C = 20 mg/mL) in Deoxygenated Water; however, the complex does react with chlorinated solvents to yield 1. Complex 2 undergoes H/D exchange with D2O, and the kinetics of this process were monitored by 31P NMR spectroscopy as a function of temperature. Activation parameters for the reaction of 2 with D2O were obtained: ΔH⧧ = 68 ± 2 kJ/mol; ΔS⧧ = −94 ± 7 J/mol·K. A normal kinetic isotope effect of 7.9 was calculated for the H/D exchange reaction described here. These kinetic parameters suggest an associative mechanism with little Ru−H (or Ru−D) bond cleavage at the transit...
Satoru Watanabe - One of the best experts on this subject based on the ideXlab platform.
-
infrared observation of the hydrogenation of si surface in Deoxygenated Water
Applied Surface Science, 1996Co-Authors: Satoru Watanabe, Yoshihiro SugitaAbstract:We have studied the removal of surface oxides from a partially oxidized Si(111) surface and the simultaneous hydrogenation of the new dangling bonds in hot Water. The amount of remaining oxides decreased by lowering dissolved-oxygen concentration (DOC) from 4 to 0.004 ppm. After immersing in hot Water with 0.004 ppm of DOC for 60 min, almost all of the surface was hydrogenated and only a tiny amount of silanol groups remained. We discuss the formation of the dihydride step-edges observed during the oxide removal.
-
Vibrational study on Si(110) surface hydrogenated in solutions
Surface Science, 1996Co-Authors: Satoru WatanabeAbstract:Abstract We have investigated the chemical structures of Si(110) surfaces hydrogenated in hydrofluoric acid and in hot Deoxygenated Water by observing the dynamic polarization of both the stretching and the bending vibrations of surface SiH bonds. The vibrations on the surface hydrogenated in Deoxygenated hot Water had anisotropic dynamic polarization. This reflected an ordered surface structure, deduced to be composed of monohydride chains along [110], as expected of an ideal hydrogenated Si(110) surface. The surface hydrogenated in hydrofluoric acid gave broad absorption features, meaning that the surface had many defects such as strained dihydride in the monohydride chains.
Honglei Jian - One of the best experts on this subject based on the ideXlab platform.
-
peptide assembly assisted triplet triplet annihilation photon upconversion in non Deoxygenated Water
Biomaterials Science, 2020Co-Authors: Yajie Tian, Jieling Li, Luyang Zhao, Xianglan Zhang, Anhe Wang, Honglei JianAbstract:Triplet–triplet annihilation upconversion (TTA-UC) has great potential in many fields. However, a stable TTA-UC system with adjustable UC efficiency in non-Deoxygenated Water is still in urgent demand. Here, the first example of short peptide-tuned UC luminescence in Water is reported. With only a small amount of peptides, UC chromophores can assemble into tetrahedral microrods with adjustable size and UC efficiency. Successful TTA-UC luminescence of these microrods in Water is achieved due to the regular and dense organization of molecular upconversion chromophores tuned by peptides, which allows rapid triplet exciton migration, avoids aggregation-induced quenching and screens molecular oxygen to upconversion chromophores.