http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Ok, Myoung-Ryul,Suh, Jin-Yoo,Chung, Sung Jae,Ji, Young Su,Hong, Kyung Tae Elsevier 2007 Materials science & engineering. properties, micro Vol.454 No.-
<P><B>Abstract</B></P><P>Bulk metallic glasses are adequate for micro-forming because of the viscous flow in the supercooled liquid state. The deformation behavior of Zr<SUB>41</SUB>Ti<SUB>14</SUB>Cu<SUB>12.5</SUB>Ni<SUB>10</SUB>Be<SUB>22.5</SUB> alloy under compression in the supercooled liquid state were investigated by using DSC and TMA. Based on the deformation behavior, micro-forming process of Zr<SUB>41</SUB>Ti<SUB>14</SUB>Cu<SUB>12.5</SUB>Ni<SUB>10</SUB>Be<SUB>22.5</SUB> alloy was designed and carried out. The surface of the deformed specimens were analyzed by SEM, XRD, and AFM. The roughness of the specimen surface exhibited a correlation with the total deformation and a new parameter reflecting roughness evolution of the deformed surface was suggested as the relative comparison among different forming conditions.</P>
Si 첨가강의 연속주조공정 신뢰성 향상을 위한 고온변형특성에 관한 연구
옥명렬(Myoung-Ryul Ok),서진유(Jin-Yoo Suh),심재혁(Jae-Hyeok Shim),홍경태(Kyung-Tae Hong),이주동(Joo-Dong Lee),임창희(Chang-hee Yim) 대한기계학회 2001 대한기계학회 춘추학술대회 Vol.2001 No.8
A study was made on the high temperature deformation behavior of Si steel to increase the reliability of continuous casting process. In continuous casting process, the cast slab experiences cooling and deformation simultaneously, and various sources for defect formation exist. Of all these defects, cracking has the most deleterious effect on the property of the cast slab. To avoid or minimize transverse cracking, unbending temperature should be chosen carefully. In general, transverse cracks can easily be formed when unbending temperature lies within the ductility minimum temperature range of hot tensile test. Relative ratio of austenite-ferrite and their distribution or morphology have significant effect on the reliability of unbending process. Moreover, inhomogeneous deformation can be the source of defect formation. So, to produce Si steel by continuous casting, deformation behavior of Si steel as well as the relative ratio of austenite-ferrite or phase transformation temperature(Ar₃) should be known. We carried out hot tensile and hot compression test to evaluate the mechanical properties of the Si steel at high temperature. Hot ductility minimum temperature was not found with all Si contents, but inhomogeneous deformation occurred in high Si(1.17% and 3.21%) samples. It can be concluded that to minimize inhomogeneous deformation is the key to the successful unbending process of silicon steel. To analyze the effect of the silicon on the strength of silicon steel, a model was established, by using rule of mixture.
The Dependence of Coating Characteristics on Progress Parameters and Alloy Compositions
Terleeva, Olga. P.,Oh, Young-Joo,Ok, Myoung-Ryul,Utkin, Vladimir V.,Ha, Heon-Phil,Lee, Dong-Heon The Japan Institute of Metals 2005 Materials transactions Vol.46 No.11
<P>The coating characteristics on the surfaces of the aluminum alloys A1230, A2017, Al–7.6 mass%Si, and Al–10.4 mass%Si formed at AC polarization were investigated. The intervals of current densities and process durations were checked, and data consisting of coating thickness and increases in size and weight were obtained. The presence of the high-temperature aluminum oxide phases, which provide high physical-mechanical coating characteristics, was registered with the help of the Bruker D8 Advanced X-ray diffractometer.</P>
Research on the surface oxidation procedure of Fe-base metallic glass during wet oxidation treatment
Kang, Eun Young,Chung, Young Hoon,Ok, Myoung-Ryul,Baik, Hong Koo Elsevier 2007 Materials science & engineering. properties, micro Vol.449 No.-
<P><B>Abstract</B></P><P>Internal structure of magnetic core for high-frequency use could be divided into small insulating units to minimize eddy current loss. Accordingly, the powder size of Fe<SUB>bal.</SUB>Si<SUB>9.6</SUB>B<SUB>14.4</SUB>Nb<SUB>4</SUB> (numbers indicate at.%) amorphous alloy should be small and covered with some degree of insulating layer for producing high-frequency magnetic core. In this investigation, formation of the insulating layer on the surface of Fe-based amorphous alloy powder was studied using wet oxidation method. The size of Fe–Si–B–Nb amorphous alloy powder used in this research was less than 75μm in diameter. Forming mechanism of surface cracks and consecutive oxide layers was explained and the thickness of insulating layer could be controlled by changing treatment time and concentration of HNO<SUB>3</SUB> in the oxidizing solution. Even though the oxide layer on the powder surface was partially flaked off during hot-compacting process, sufficient electrical resistance was maintained to lessen eddy current loss effectively.</P>
Terleeva, O. P.,Oh, Young-Joo,Ok, Myoung-Ryul,Slonova, A. I.,Kireenko, I. B.,Lee, Dong-Heon The Japan Institute of Metals 2006 MATERIALS TRANSACTIONS Vol.47 No.7
<P>The structure and phase composition of microplasma coatings formed on a Ti-6Al-4V alloy using the alternating current mode in solutions with different concentrations of KOH, NaAlO<SUB>2</SUB> and Na<SUB>6</SUB>P<SUB>6</SUB>O<SUB>18</SUB> were investigated using XRD analysis, microscope analysis and microhardness testing. The thickness and weight gain were measured with electronic thickness gage and correspondingly, with the gravimetric method. The crystal structure of the microplasma electrolytic coatings had amorphous, rutile, α-Al<SUB>2</SUB>O<SUB>3</SUB> and Al<SUB>2</SUB>TiO<SUB>5</SUB> phase. The coating morphology may be presented as 3 layers—the external amorphous layer, the internal layer, and the barrier layer.</P>
Femtosecond Laser Ablation of Polymer Thin Films for Nanometer Precision Surface Patterning
Indong Jun,Jee-Wook Lee,Myoung-Ryul Ok,Yu-Chan Kim,Hojeong Jeon 한국표면공학회 2016 한국표면공학회지 Vol.49 No.1
Femtosecond laser ablation of ultrathin polymer films on quartz glass using laser pulses of 100 fs and centered at λ=400 nm wavelength has been investigated for nanometer precision thin film patterning. Singleshot ablation craters on films of various thicknesses have been examined by atomic force microscopy, and beam spot diameters and ablation threshold fluences have been determined by square diameter-regression technique. The ablation thresholds of polymer film are about 1.5 times smaller than that of quartz substrate, which results in patterning crater arrays without damaging the substrate. In particular, at a 1/e<SUP>2</SUP> laser spot diameter of 0.86 μm, the smallest craters of 150-nm diameter are fabricated on 15-nm thick film. The ablation thresholds are not influenced by the film thickness, but diameters of the ablated crater are bigger on thicker films than on thinner films. The ablation efficiency is also influenced by the laser beam spot size, following a w0q<SUP>-0.45</SUP> dependence.
Ji, Young Su,Chung, Sung Jae,Ok, Myoung-Ryul,Hong, Kyung Tae,Suh, Jin-Yoo,Byeon, Jai Won,Yoon, Jin-Kook,Lee, Kyung Hwan,Lee, Kyung Sub Elsevier 2007 Materials science & engineering. properties, micro Vol.449 No.-
<P><B>Abstract</B></P><P>The crystallization behavior of Cu<SUB>43</SUB>Zr<SUB>43</SUB>Al<SUB>7</SUB>Ag<SUB>7</SUB> (numbers indicate at.%) bulk metallic glass was investigated using the isothermal electrical resistivity measurements at 450°C in the supercooled liquid region. The crystallization process is a single step phase transformation. To analyze the electrical resistivity reduction, microstructure evolutions were analyzed using differential scanning calorimetry, X-ray diffraction, transmission electron microscopy and small-angle X-ray scattering. The Avrami parameter of the electrical resistivity reduction step was 1.73, indicating that the crystallization process is a diffusion-controlled growth of intermetallic compounds with decreasing nucleation rate.</P>