하악 고정성 임프란트를 이용한 퇴축된 하악골의 수복

정영진,박원희,안원준,이명렬,이영수,유광희,심광섭 한양대학교 의과대학 1997 한양의대 학술지 Vol.17 No.2

Transmandibular implants are used limitedly such as on remaining symphyseal basal bone of atrophic mandible, on the bony defect of symphyseal area due to trauma or tumor as surgical implants. Among the more recent advances in oral implantology are the Fixed Mandibular Implant (FMI)based on the pioneering studies and clinical applications by Irwin Small of the USA and the development very high success rates for providing attachments and abutments in areas of the oral cavity severely compromised by either atrophy or surgical loss of osseous tissues. We will present a case report of regabilitation of totally edentulous mandible with advanced alveolar atrophy using Fixed Mandibular implant (F.M.I).

Manipulating ion-induced ripple formation on Au(001)

Minwoong Joe,Byungnam Kahng,Jae-Sung Kim,Kwang-Ryeol Lee1 한국표면공학회 2009 한국표면공학회 학술발표회 초록집 Vol.2009 No.-

생체모사환경에서 DLC 필름의 부식마모 특성에 미치는 Si 함량의 영향에 관한 연구

김호건,김우중,김정구,박세준,이광렬 대한금속재료학회 2005 대한금속·재료학회지 Vol.43 No.3

In a method to improve resistance to wear, corrosion and mechanical properties of protective coating, DLC coatings have been extensively studied over the past several years due to their unique combination of properties. Especially, Si-DLC coatings have been attracting increasing interest of researchers since they have a great potential for solving some of the major disadvantages of pure DLC coatings. Si-incorporated diamond-like carbon (Si-DLC) coatings ranging from 0 to 2 at.% were deposited on Ti alloy substrate by means of r.f. plasma-assisted chemical vapor deposition (r.f. PACVD) technique, using mixtures of benzene (C_(6)H_(6)) and silane (SiH_(4)) as the reaction gases. Corrosion and wear behavior of DLC coatings was investigated by electrochemical techniques (potentiodynamic polarization test and electrochemical impedance spectroscopy), tribological techchnique(wear test) and surface analyses (atomic force microscopy, scanning electron microscopy and Raman spectroscopy). It was found that DLC coatings with increasing Si content could acquire improved corrosion and wear resistance in the simulated body fluid environment (0.89 wt.% NaCl of pH 7.4 at 37℃). (Received December 6, 2004)

인공고관절용 스테인리스강 316L에 증착된 다이아몬드상 카본 필름의 전기화학적 특성에 관한 연구

김호건,안승호,김정구,박세준,이광렬 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.4

Diamond-like carbon (DLC) films have several advantages in applications such as high hardness, chemical inertness, low friction and electrical insulation. Furthermore, DLC-coated STS 316L films have been reported to have a good biocompatibility, such as the absence of inflammatory response. Thus, corrosion resistance is the first consideration for the biomaterials to be used in the body. DLC films have been deposited onto substrates of STB 316L for artificial hip joints using r.f PACVD (plasma-assisted chemical vapor deposition) with C_(6)H_(6) and mixture of C_(6)H_(6) and SiH_(4) as the process gases. Three kinds of DLC-coated films were prepared as a function of diverse bias voltage and Si incorporation. Corrosion behavior of DLC films was investigated by electrochemical techniques (potentiodynamic polarization test and electrochemical impedance spectroscopy) and surface analyses (atomic force microscopy and scanning electron microscopy). The electrolyte used in his test was a 0.89%NaCl solution of pH 7.4 at temperature 37℃. Electrochemical measurements showed that DLC films with higher bias voltage and Si incorporation could improve corrosion resistance in the simulated body fluid environment. (Received December 5, 2003)

A modified embedded-atom method interatomic potential for ionic systems:2NNMEAM+Qeq

Lee, Eunkoo,Lee, Kwang-Ryeol,Baskes, M. I.,Lee, Byeong-Joo American Physical Society 2016 Physical Review B Vol.93 No.14

<P>An interatomic potential model that can simultaneously describe metallic, covalent, and ionic bonding is suggested by combining the second nearest-neighbor modified embedded-atom method (2NNMEAM) and the charge equilibration (Qeq) method, as a further improvement of a series of existing models. Paying special attention to the removal of known problems found in the original Qeq model, a mathematical form for the atomic energy is newly developed, and carefully selected computational techniques are adapted for energy minimization, summation of Coulomb interaction, and charge representation. The model is applied to the Ti-O and Si-O binary systems selected as representative oxide systems for a metallic element and a covalent element. The reliability of the present 2NNMEAM + Qeq potential is evaluated by calculating the fundamental physical properties of a wide range of titanium and silicon oxides and comparing them with experimental data, density functional theory calculations, and other calculations based on (semi-)empirical potential models.</P>

Computational approach to understand the dynamics of interfacial phenomena

Kwang-Ryeol LEE 한국진공학회 2016 한국진공학회 학술발표회초록집 Vol.2016 No.8

Real-Time “Eye-Writing” Recognition Using Electrooculogram

Kwang-Ryeol Lee,Won-Du Chang,Sungkean Kim,Chang-Hwan Im IEEE 2017 IEEE transactions on neural systems and rehabilita Vol.25 No.1

<P>Eye movements can be used as alternative inputs for human-computer interface (HCI) systems such as virtual or augmented reality systems as well as new communication ways for patients with locked-in syndrome. In this study, we developed a real-time electrooculogram (EOG)-based eye-writing recognition system, with which users can write predefined symbolic patterns with their volitional eye movements. For the “eye-writing” recognition, the proposed system first reconstructs the eye-written traces from EOG waveforms in real-time; then, the system recognizes the intended symbolic inputs with a reliable recognition rate by matching the input traces with the trained eye-written traces of diverse input patterns. Experiments with 20 participants showed an average recognition rate of 87.38% (F1 score) for 29 different symbolic patterns (26 lower case alphabet characters and three functional input patterns representing Space, Backspace, and Enter keys), demonstrating the promise of our EOG-based eye-writing recognition system in practical scenarios.</P>

Networked interpenetrating connections of icosahedra: Effects on shear transformations in metallic glass

Lee, Mirim,Lee, Chang-Myeon,Lee, Kwang-Ryeol,Ma, Evan,Lee, Jae-Chul Elsevier 2011 Acta materialia Vol.59 No.1

<P><B>Abstract</B></P><P>The local structures of metallic glasses have been analyzed previously in term of various types of short-range order (SRO). However, the SRO alone, neglecting the interconnection of neighboring icosahedra to medium range and beyond, is insufficient to account for the structure–property relationship in metallic glasses. In this study, we use molecular dynamics (MD) simulations of Cu–Zr binary metallic glasses to examine the effects of the next level of structural hierarchy: the interpenetrating connection of icosahedra (ICOI) and the linkage of the medium-range ICOI patches to form networks of icosahedra over extended range. The mechanical properties of these metallic glasses, especially the shear transformations that mediate plasticity, are found to be dependent on the degree of ICOI and development of the ICOI network. The evolution of the ICOI network during shear deformation, as well as the composition dependence, has been monitored and discussed.</P>

Interatomic Potential of Li–Mn–O and Molecular Dynamics Simulations on Li Diffusion in Spinel Li_1–<i>x</i>Mn₂O₄

Lee, Eunkoo,Lee, Kwang-Ryeol,Lee, Byeong-Joo American Chemical Society 2017 The Journal of Physical Chemistry Part C Vol.121 No.24

<P>An interatomic potential of the Li-Mn-O ternary system has been developed on the basis of the second-nearest-neighbor modified embedded-atom method(2NN MEAM) formalism combined with a charge equilibration (Qeq) concept. The potential reproduces fundamental physical properties (structural, elastic, thermodynamic and migration properties) of various compounds well, including lithium oxides, manganese oxides, and lithium manganese ternary oxides. Through molecular dynamics (MD) simulations using the developed potential, lithium diffusion properties (activation energy for lithium migration and diffusion coefficient) in spinel Li1-xMn2O4 are also reproduced in good agreement with experiments. We have found that the effect of the lithium vacancy concentration is marginal on the activation energy for lithium diffusion in the Li1-xMn2O4 cathode, but it is significant in the lithium diffusion coefficient. The potential can be further utilized for atomistic simulations of various materials phenomena (phase transitions, defect formation, lithiation/delithiation, etc.) in LIB cathode materials.</P>

Correlation between the time elapsed after liposuction and the risk of fat embolism: An animal model

Lim, Kwang-Ryeol,Cho, Jeong-Min,Yoon, Chung-Min,Lee, Keun-Cheol,Lee, Sang-Yun,Ju, Mi-Ha Korean Society of Plastic and Reconstructive Surge 2018 Archives of Plastic Surgery Vol.45 No.1

Background Liposuction has become one of the most frequently performed procedures in the field of aesthetic surgery. Fat embolism syndrome after liposuction can easily be overlooked or underestimated; however, occasionally, fulminating fat embolism syndrome can develop and lead to a critical situation within 2-3 days after lipoplasty. Changes over time in the amount of circulating fat particles and the histology of major organs have not yet been studied. Methods This study was conducted using 18 male Sprague-Dawley rats aged 12 weeks and weighing 500-628 g (average, 562 g). Fifteen rats were used as the experimental group and 3 as the control group. Under general anesthesia, tumescent-technique liposuction was performed at the lateral flank areas and abdomen for 1 hour. Blood, lung, and brain tissue specimens were obtained at 1 hour, 1 day, and 2 days after the liposuction procedure. Results The average number of fat particles in the blood samples was 25,960/dL at 1 hour, 111,100/dL at 24 hours, and 21,780/dL at 48 hours. The differences between study groups were statistically significant. Both intravascular and extravascular fat particles with inflammation were seen in all 15 rats, as were inflammatory cell infiltration, hemorrhage, and consolidation with shrinkage of the lung alveoli. Conclusions These results imply that there is a strong possibility of fat embolism syndrome after liposuction in real clinical practice, and the first 24-48 hours after the operation were found to be the most important period for preventing pulmonary embolism and progression to fulminating fat embolism syndrome.