Microstructural Stability and Creep Performance of a Novel Low-Cost Single Crystal Superalloy

Z. H. Tan,X. G. Wang,Y. L. Du,Y. M. Li,Y. H. Yang,J. L. Liu,J. D. Liu,J. G. Li,Y. Z. Zhou,X. F. Sun 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

The increasing pursuit of advanced aero-engines with lower ratio between the cost and performance has greatly promotedthe demanding of single crystal superalloys characterized by low cost and outstanding temperature capability. In this study,a novel low-cost single crystal superalloy was designed and the creep tests as well as micro-characterization were carried outon the experimental alloy. The results illustrated that the novel single crystal alloy exhibited an ideal microstructural stabilitywithout precipitating TCP phases, after long-term thermal exposure at the ultimate service temperature of third generationsingle crystal superalloys. Moreover, the experimental alloy with only 3 wt% Re addition demonstrated remarkable creepresistance and maintained a very low minimum creep rate at 1100 °C/137 MPa and 1120 °C/137 MPa, while the accumulationand coalescence of micro-pores had eventually led to the alloy fracture. Apart from that, the compact interfacial dislocationnetworks the 2nd γ′ phase were observed after high-temperature creep rupture, and the typical a < 010 > superdislocationswith relatively poor mobility was found at 1120 °C. At 760 °C/800 MPa, both the minimum creep velocity and entire creepstain was increased evidently, however, the ultimate creep rupture life of the alloy had still reached 200 h. The correspondingdeformation mechanism was identified as the combination of superdislocation pairs shearing and a/3 < 121 > partial dislocationcutting the γ′ phase with a SISF being generated. In general, the novel single crystal alloy characterized by remarkablemechanical properties and cost reduction possesses a great potential for future application in the advanced aircraft engines.

Dietary Foeniculum vulgare Mill extract attenuated UVB irradiation-induced skin photoaging by activating of Nrf2 and inhibiting MAPK pathways

Sun, Z.,Park, S.Y.,Hwang, E.,Park, B.,Seo, S.A.,Cho, J.G.,Zhang, M.,Yi, T.H. G. Fischer 2016 Phytomedicine Vol.23 No.12

<P>Background: Foeniculum vulgare Mill (FV) has long been prescribed in traditional medicine due to its antioxidant anti-inflammatory properties. However, little research has been done on the use of FV to alleviate changes in UVB-induced photoaging Purpose: This study was to investigate the photoprotective effects and mechanism of FV in vitro and in vivo. Methods: The anti-photoaging effect of FV was assessed in normal human dermal fibroblasts (NHDFs) in vitro. The secretion of reactive oxygen species (ROS), lactate dehydrogenase (LDH), GSH, matrix metalloproteinases (MMPs), procollagen type I, IL-6 and transforming growth factor-beta 1 (TGF-beta 1) were measured by kits. Additionally, the level of nuclear factor (erythroid-derived 2)-like 2 (Nrf2), p-ERK and p38 were evaluated by western blotting. In vivo, H&E and Masson's trichrome staining were employed. The expression of MMP-1, procollagen type I, TGF-beta 1 and elastin were measured by western blot. Results: FV significantly increased the production of collagen, elastin and TGF-beta 1 levels, while blocked matrix metalloproteinases (MMPs) production in UVB irradiation induced hairless mice, which were consistent with the result in NHDFs. Furthermore, FV dose-dependently decreased the production of ROS and LDH by promoting the nuclear amount of Nrf2 and enhancing the expression of cytoprotective antioxidants such as GSH. FV also significantly quenched UVB-induced phosphorylation of ERK and p38 in NHDFs. Conclusion: Our results indicate that FV is a potential botanical agent for the treatment of skin damage induced by UV irradiation. (C) 2016 Elsevier GmbH. All rights reserved.</P>

Evolution of microstructure and tensile properties of Fe-18Ni-12Cr based AFA steel during aging at 700^oC

Wang, M.,Sun, H.,Phaniraj, M.P.,Han, H.N.,Jang, J.,Zhou, Z. Elsevier Sequoia 2016 Materials science & engineering. properties, micro Vol.672 No.-

<P>The effects of aging at 700 degrees C on the microstructure and tensile properties of an alumina-forming austenitic (AFA) stainless steel were investigated. With increasing aging time, B2-NiAl and Laves phase precipitated first on grain boundaries (GB) and then in the grain interior. The GB precipitate coverage reached 74% after aging for 1000 h. The GB precipitates not only suppressed grain coarsening during aging, but also influenced the tensile fracture mode at 700 degrees C by partitioning stress concentration on triple junctions. Moreover plate-like and spherical NbC particles precipitated during aging. Spherical NbC with size of around 5 nm were stable, while plate-like NbC grew to 89 nm after aging for 1000 h. These precipitates played an important role on the tensile strength. Age hardening contributed to the increasing tensile strength at RT with aging time, while the softening mechanism of dynamic recovery dominated the tensile tests at 700 degrees C. (C) 2016 Elsevier B.V. All rights reserved.</P>

Fluorinated Metal Hydrides for the Catalytic Hydrolysis of Metal - Hydrogen Complexes

Suda, S,Zhou, Y,Sun, Y M,Uchida, M,Liu, B H,Mormitu, S,Arai, K,Tsukamoto, N,Candra, Y,LI, Z P 대한금속재료학회(대한금속학회) 2001 METALS AND MATERIALS International Vol.7 No.1

This paper is related to the hydrogen storage (H-storage) system composed of an alkaline solution that contains metal-hydrogen complex ions. The BH₄^--complex ions stabilized when it is dissolved in aqueous KOH or NaOH to form homogeneous solutions. However, it is necessary to apply an appropriate catalyst for a high rate generation of hydrogen under atmospheric pressure and temperature conditions. The authors intended to develop catalysts suitable for the hydrolysis of BH₄^--complex ion solutions and found that Mg₂Ni exhibits excellent catalytic functions in the hydrolysis, in particular, after the fluorination treatment (F-treatment). In this work, the effects of F-treatment on the rates of hydrolysis were evaluated between the hydrided and unhydrided Mg₂Ni. No hydrogenation in addition to F-treatment is required in view of hydrolysis kinetics and cost-effectiveness.

Tanshinone IIA suppresses inflammatory bone loss by inhibiting the synthesis of prostaglandin E₂ in osteoblasts

Kwak, H.B.,Sun, H.M.,Ha, H.,Kim, H.N.,Lee, J.H.,Kim, H.H.,Shin, H.I.,Lee, Z.H. North-Holland ; Elsevier Science Ltd 2008 european journal of pharmacology Vol.601 No.1

Tanshinone IIA isolated from Danshen is widely used in Oriental medicine. However, the action of tanshinone IIA in inflammatory bone-resorptive diseases remains unknown. Here we examined the effect of tanshinone IIA in inflammation-mediated osteoclastic bone resorption. Tanshinone IIA inhibited osteoclast differentiation in cocultures of bone marrow cells and calvarial osteoblasts. Tanshinone IIA regulated the expression of receptor activator of NF-κB ligand and osteoprotegerin in osteoblasts treated with lipopolysaccharide (LPS). Also, tanshinone IIA inhibited prostaglandin E<SUB>2</SUB> (PGE<SUB>2</SUB>) synthesis by inhibiting Cyclooxygenase-2 (COX-2) expression induced by LPS. Furthermore, tanshinone IIA greatly suppressed bone loss in the mouse models of bone loss. Our findings suggest that tanshinone IIA inhibits osteoclast formation by inhibiting COX-2/PGE<SUB>2</SUB> signaling and by suppressing bone erosion in vivo. These results suggest that tanshinone IIA may be of therapeutic value as an anti-bone-resorptive drug in the treatment of bone-related disease.

Effects of Intra-duodenal Infusion of Limiting Amino Acids on Plasma Insulin-like Growth Factor I, Growth Hormone, Insulin and Liver Insulin-like Growth Factor I mRNA in Growing Goat Fed a Maize Stover-based Diet

Sun, Z.H.,Tan, Z.L.,Yao, J.H.,Tang, Z.R.,Shan, J.G.,Hu, J.P.,Tang, S.X.,Jiang, Y.M. Asian Australasian Association of Animal Productio 2007 Animal Bioscience Vol.20 No.5

The effects of intra-duodenal infusion of methionine (Met), lysine (Lys) and leucine (Leu) on dry matter intake (DMI), the concentrations of insulin-like growth factor I (IGF-I), growth hormone (GH) and insulin in plasma, and liver IGF-I mRNA level were investigated in two experiments for Liuyang Black growing wether goats. In Experiment 1, three goats ($10.0{\pm}0.1$ kg) were fitted with ruminal, proximal duodenal and terminal ileal fistulaes to determine the infusion amounts of Met, Lys and Leu at the duodenum according to essential amino acid flows into the duodenum and their apparent digestibility. The infusion amounts were 0.77 g/d, 0.91 g/d and 0.58 g/d respectively. In Experiment 2, 4 groups of goats (($10.0{\pm}0.2$ kg) for each group, were cannulated at the duodenum, and were infused with a mixture of Met, Lys and Leu (Control), or mixtures with 21% Met, Lys or Leu replaced with glutamate respectively on a nitrogenous basis. The replacement of 21% Met, Lys or Leu with glutamate did not affect intakes of maize stover, concentrate or both (p>0.05) when compared with the control. The replacement of 21% Met or Lys significantly (p<0.05) reduced plasma GH, insulin and IGF-I concentrations and liver IGF-I mRNA level. The replacement of 21% Leu with glutamate reduced (p<0.05) plasma IGF-I concentration only, but not plasma insulin and GH, as well as liver IGF-I mRNA level (p>0.05). The close relationships between supplying Met and Lys in the lumen of the duodenum and plasma IGF-I, GH and insulin concentrations, as well as liver IGF-I mRNA level in this study indicate that the effects of the limiting amino acids on nutrition of animals are likely intermediated via their effects on these hormones, and these hormone profiles could be used as intermediate markers for the limiting order of amino acids.

Status and Prospect of Test Methods of Quality Silicone Water Repellent for Protecting Reinforced Concrete

( H. Y. Sun ),( Z. Y. Yuan ),( Z. Yang ),( G. L. Shan ),( M. X. Shen ) 한국부식방식학회 2017 Corrosion Science and Technology Vol.16 No.3

Impregnating with quality silicone water repellent on the concrete surface is an effective method of protecting concrete. Quality silicone water repellent has been widely used in the engineering profession because of its desirable properties such as hydrophobicity, keeping concrete breathable and preserving the original appearance of the concrete. The companies in China that produce silicone water repellent are listed. Test methods in the specifications or standards about silicone water repellent in China are summed. The test methods relative to durability of concrete impregnated with silicone water repellent (such as resistant to chloride ion penetration, resistant to alkali, resistance to freezing and thawing and weatherability etc.) and the constructive quality (such as water absorption rate, impregnating depth and the dry velocity coefficient etc.) are compared and analyzed. The results indicate that there are differences among test methods relative to different specifications with the same index and therefore, confusion has ensued when selecting test methods. All test methods with the exception of the method of water absorption rate by using a Karsten flask are not non-destructive methods or conducted in a laboratory. Finally, further research on silicone water repellent during application is proposed.

Studies on the Genetic Relationships of Sheep Populations from East and South of Central Asia

Sun, W.,Chang, H.,Yang, Z.P.,Geng, R.Q.,Lu, S.X.,Chang, G.B.,Xu, W.,Wang, H.Y.,Ren, Z.J.,Tsunoda, K. Asian Australasian Association of Animal Productio 2002 Animal Bioscience Vol.15 No.10

Hu sheep was sampled randomly from Huzhou city, Zhejiang province, China. Of the 11 genetic markers from the blood examined by starch-gel and cellulose acetate electrophoresis, polymorphisms in Hu sheep were found for 10 loci, i.e. post-albumin (Po), transferring (Tf), alkaline phosphatase (Alp), leucine aminopeptidase (Lap), arylesterase (Ary-Es), hemoglobin-$\beta$ (Hb-$\beta$)、Xprotein(X-p), carbonic anhydrase (CA), catalase (Cat) and lysine (Ly). The same data except for Po locus were collected from another 14 sheep breeds from China and other countries, in order to ascertain their genetic relationships with one another and with the Hu sheep. The sheep populations from the east and south of Central Asia can be classified into three genetic groups: 'Mongolian sheep', 'South Asian sheep' and 'European sheep'. The Hu sheep belong to the 'Mongolian sheep' group.

Effect of Mn Doping on the Electronic Structures of CaCu3Ti4O12 Ceramics

Z. H. Sun,김철환,H. B. Moon,Y. H. Jang,C. H. Song,Y. S. Yang,J. H. Cho 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.2

In order to understand the drastic decrease in the permittivity in Mn-doped CCTO compounds (CCMTO), we report the effect of Mn dopant on the electronic structure of CCTO by using X-ray photoelectron spectroscopy (XPS). The XPS results show that Mn doping has a strong influence on the valence band and core levels of CCTO. The disorder at Ca/Cu sites is observed in polycrystalline CCTO, but not in CCMTO. The drastic decrease in the permittivity in CCMTO can be attributed to two reasons: the suppression of the Ca/Cu disorder and the removal of the grain boundary (internal) barrier layer capacitance mechanism.

Status and Prospect of Test Methods of Quality Silicone Water Repellent for Protecting Reinforced Concrete

Sun, H.Y.,Yuan, Z.Y.,Yang, Z.,Shan, G.L.,Shen, M.X. The Corrosion Science Society of Korea 2017 Corrosion Science and Technology Vol.16 No.2

Impregnating with quality silicone water repellent on the concrete surface is an effective method of protecting concrete. Quality silicone water repellent has been widely used in the engineering profession because of its desirable properties such as hydrophobicity, keeping concrete breathable and preserving the original appearance of the concrete. The companies in China that produce silicone water repellent are listed. Test methods in the specifications or standards about silicone water repellent in China are summed. The test methods relative to durability of concrete impregnated with silicone water repellent (such as resistant to chloride ion penetration, resistant to alkali, resistance to freezing and thawing and weatherability etc.) and the constructive quality (such as water absorption rate, impregnating depth and the dry velocity coefficient etc.) are compared and analyzed. The results indicate that there are differences among test methods relative to different specifications with the same index and therefore, confusion has ensued when selecting test methods. All test methods with the exception of the method of water absorption rate by using a Karsten flask are not non-destructive methods or conducted in a laboratory. Finally, further research on silicone water repellent during application is proposed.