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81.
Woo-Gon Kim Jae-Young Park I. M. W. Ekaputra Sung-Deok Hong Seon-Jin Kim Yong-Wan Kim 《Journal of Mechanical Science and Technology》2013,27(8):2331-2340
This paper presents a comparative investigation on the high-temperature tensile and creep properties of Alloy 617 base metal (BM) and weld metal (WM) fabricated by a gas tungsten arc weld process. The WM had higher yield strength and lower ultimate tensile strength than the BM does; however, its elongation was significantly lower than that of the BM. The creep curve of the BM and WM was somewhat different from that of typical heat-resistance steel, and did not show a textbook creep. The WM exhibited a longer creep rupture life, lower creep rate, and lower rupture ductility than the BM. However, as the creep rupture time reached approximately 36,800 h, the creep life of the WM was expected to be almost similar to that of the BM; and after 36,800 h, its creep life was expected to be worse than the BM. Loner creep tests is needed to investigate the long-term creep life of the WM. The creep failure mode of the BM and WM was obviously an intergranular cracking of the cavity formation and growth mechanisms, although it was more evident in the WM. The BM had a more ductile fracture surface than the WM. 相似文献
82.
Tae-Young Kim Jae-Kyung Park Yam Prasad Aryal Eui-Seon Lee Sanjiv Neupane Shijin Sung Elina Pokharel Chang-Yeol Yeon Ji-Youn Kim Jae-Kwang Jung Hitoshi Yamamoto Chang-Hyeon An Youngkyun Lee Wern-Joo Sohn Il-Ho Jang Seo-Young An Jae-Young Kim 《International journal of molecular sciences》2020,21(22)
In the present study, we examined the bone healing capacity of Meox2, a homeobox gene that plays essential roles in the differentiation of a range of developing tissues, and identified its putative function in palatogenesis. We applied the knocking down of Meox2 in human periodontal ligament fibroblasts to examine the osteogenic potential of Meox2. Additionally, we applied in vivo periodontitis induced experiment to reveal the possible application of Meox2 knockdown for 1 and 2 weeks in bone healing processes. We examined the detailed histomorphological changes using Masson’s trichrome staining and micro-computed tomography evaluation. Moreover, we observed the localization patterns of various signaling molecules, including α-SMA, CK14, IL-1β, and MPO to examine the altered bone healing processes. Furthermore, we investigated the process of bone formation using immunohistochemistry of Osteocalcin and Runx2. On the basis of the results, we suggest that the knocking down of Meox2 via the activation of osteoblast and modulation of inflammation would be a plausible answer for bone regeneration as a gene therapy. Additionally, we propose that the purpose-dependent selection and application of developmental regulation genes are important for the functional regeneration of specific tissues and organs, where the pathological condition of tooth loss lesion would be. 相似文献
83.
Ki Beom Park Jaeho Choi Sung Yong Lee Jae-Young Park Tae-Wook Na Jong-In Choi 《Materials Science & Technology》2020,36(12):1372-1380
The present study investigated the sintering behaviour of Nb–16Si–25Ti–8Hf–2Cr–2Al alloy powders. The alloy powders were produced using ahydrogenation–dehydrogenation method and featured an irregular morphology. Powders sintered at 1500°C and 1600°C exhibited pores in their microstructures, while powders sintered at 1700°C for 4?h were fully densified and poreless. The cast ingot and powders were composed of three phases: Nbss, Nb5Si3, and Nb3Si. However, the Nb3Si phase was not observed, while HfO2 oxides formed in the sintered compact. The hafnium and oxygen reacted to form an HfO2 oxide during the high-temperature sintering process. From the result of the thermodynamic calculation, Hf oxide formed after sintering because Hf has the highest driving force for oxidation among the elements constituting the alloy. 相似文献
84.
Kumar E Bhatnagar A Ji M Jung W Lee SH Kim SJ Lee G Song H Choi JY Yang JS Jeon BH 《Water research》2009,43(2):490-498
This research was undertaken to evaluate the feasibility of granular ferric hydroxide (GFH) for fluoride removal from aqueous solutions. Batch experiments were performed to study the influence of various experimental parameters such as contact time (1 min-24 h), initial fluoride concentration (1-100 mg L−1), temperature (10 and 25 °C), pH (3-12) and the presence of competing anions on the adsorption of fluoride on GFH. Kinetic data revealed that the uptake rate of fluoride was rapid in the beginning and 95% adsorption was completed within 10 min and equilibrium was achieved within 60 min. The sorption process was well explained with pseudo-first-order and pore diffusion models. The maximum adsorption capacity of GFH for fluoride removal was 7.0 mg g−1. The adsorption was found to be an endothermic process and data conform to Langmuir model. The optimum fluoride removal was observed between pH ranges of 4-8. The fluoride adsorption was decreased in the presence of phosphate followed by carbonate and sulphate. Results from this study demonstrated potential utility of GFH that could be developed into a viable technology for fluoride removal from drinking water. 相似文献
85.
M. Hidaka K. Ohashi S. Kajihara R.P. Wijesundera L.S.R. Kumara Jae-Young Choi Nark Eon Sung 《Ceramics International》2009,35(2):875-886
HIZEN porcelains made in 1650s to 1750s (early Edo period) in Arita areas sited in south Japan (SAGA) are famous Japanese porcelains, which are characterized by elegant and bright colors in the overglaze and the underglaze. Red-overglazes and transparent glazes of the HIZEN porcelains have been investigated by means of X-ray diffraction (XRD) and X-ray absorption spectra (XAS) using synchrotron radiation. The results suggest that the red-color brightness of the Hizen porcelains is mainly induced by micro-structural correlation between α-Fe2O3 fine particles of red-color emission element and the oxide complexes of SiO2–Al2O3–CaO–KNaO or SiO2 in the fritted overglazes. The stability of the red-color overglaze on the porcelain body of white-color results from interfacial fusion between both glass-states in the fritted overglaze and the transparent glaze coating the porcelain body. The refined local structures around Fe ions of the α-Fe2O3 structure taken EXAFS spectra give the technical and historical relation among four kinds of the HIZEN porcelains for fritted materials of the overglazes and thermal treatment at high-temperature in the porcelain kilns. 相似文献
86.
Fiber orientation effects on the impact surface fracture of glass plates coated with a glass-fiber/epoxy lamina layer were investigated using a small-diameter steel-ball impact experiment. Four kinds of materials were used: soda-lime glass plates, unidirectional glass-fiber/epoxy layer (one ply, two plies) coated glass plates, crossed glass-fiber/epoxy layer (only two plies) coated glass plates. The maximum stress and absorbed fracture energy of these plates were measured by a single-grid strain gage bonded to the back surface of the glass plates during the impact of the steel ball. With increasing impact velocity, various surface cracks, such as ring, cone, radial and lateral cracks, occurred near the impact sites of the uncoated glass plates. Plates with glass-fiber coating had a plastic deformation zone between the fiber layer and the glass plate that formed around the impact site while the surface cracks in the plates drastically diminished. The principal direction of this plastic deformation and delamination followed the fiber orientation. The impact surface-fracture index expressed in terms of the maximum stress and the absorbed energy could be used as an effective evaluation parameter for surface resistance. 相似文献
87.
Dong-Woo Suh Jae-Young Cho Kotobu Nagai 《Metallurgical and Materials Transactions A》2004,35(11):3399-3408
The microstructural evolutions of Ni-30Fe alloys during hot deformation are investigated. Hot-deformed structures of Ni-30Fe
alloys with initial austenite grain sizes of 20 and 140 μm are examined under various compressive strains and deformation
temperatures. As the initial austenite grain size decreases, dynamic recrystallization (DRX) occurs at lower compressive strain
and lower deformation temperature. At deformation temperatures where dynamic recovery occurs instead of the DRX, hot-deformed
structures consist of recovered elongated grains until fine-equiaxed grains are evolved by geometric DRX. Critical compressive
strain for the geometric DRX decreases with the decrease of initial austenite grain size. Geometric DRX is evolved by the
impingement of serrated grain boundaries. The decrease of initial grain size is considered to reduce the critical compressive
strain needed for the impingement of serrated grain boundaries. The changes in the effective thickness of austenite grain
according to the compressive deformation are examined and the effects of the restoration processes on the effective thickness
of austenite grain are discussed. 相似文献
88.
Kang-Min Kim Jong-Heun Lee Seon-Mi Yoon Hyun-Chul Lee Yong-Kyun Lee Jae-Young Choi 《Journal of Electroceramics》2006,17(2-4):339-343
Mono-disperse and spherical Ni powders were prepared using a N2H4-based solution reduction route. The main focus was on manipulating the particle size by varying the source materials (Ni-chloride, Ni-sulfate and Ni-acetate) and impurity concentrations. The morphology and size of the Ni particle closely depended on the source materials. In addition, the particle size became significantly smaller with increasing Co concentration ranging from 0 to 350 ppm. The decrease in the Ni particle size was attributed to the promotion of nucleation by the rapid decomposition of the CoCl2–N2H4 complex when adding a NaOH solution and the more active reduction of Co than that of Ni in the initial stages of the reaction. 相似文献
89.
Sea-Hoon Lee Gerhard Kaiser Georg Rixecker Fritz Aldinger Jae-Young Park Keun-Ho Auh Sung-Churl Choi 《Journal of the American Ceramic Society》2008,91(2):679-682
The surface of Si3 N4 ceramics was hydrothermally treated with HCl or H2 SO4 using an autoclave. The thickness of the oxide layers formed on the Si3 N4 samples decreased to one-fourth after oxidation at 1400°C by the treatment. The oxide layer of the treated samples was dense, and flaw formation in and beneath the layer did not occur at 1400°C. The avoidance of low melting Y-silicates by leaching Y2 O3 is the reason for the improved oxidation resistance of the hydrothermally treated Si3 N4 , despite an increase in surface porosity through a 70 μm layer. 相似文献
90.
Genetically engineered elastin-protein A fusion as a universal platform for homogeneous, phase-separation immunoassay 总被引:1,自引:0,他引:1
A simple and universal platform for competitive phase-separation immunoassay is reported based on a fusion protein composed of a temperature-responsive elastin-like polypeptide (ELP) and the antibody-binding staphylococcal protein A (SpA). The basic principle is to take advantage of the ability of SpA to bind a variety of antibodies with high affinity, allowing simple separation of antigen-antibody complex by thermal precipitation. The resulting ELP-SpA fusion was shown to preserve the ability to reversibly precipitate as well as its high affinity toward different IgGs and IgMs. As a model system, a competitive phase-separation immunoassay based on the ELP-SpA format was established for paclitaxel (taxol) with IC(50) (20.18 nM) and the lower detection limit (2.94 nM) very similar to those reported for the ELISA format. Unlike the heterogeneous interaction in ELISA, which decreases the antibody-binding activity, the reported homogeneous immunoassay not only alleviates this problem but also enables the potential for high-throughput automation. We believe that the reported ELP-SpA fusion will find applications not only as a powerful diagnostic tool for diverse analytes but also a potential useful tool for purification and immobilization of antibody. 相似文献