New bimaxillary orthognathic surgery planning and model surgery based on the concept of six degrees of freedom

Jeon, Jaeho,Kim, Yongdeok,Kim, Jongryoul,Kang, Heejea,Ji, Hyunjin,Son, Woosung The Korean Association Of Orthodontists 2013 대한치과교정학회지 Vol.43 No.1

The aim of this paper was to propose a new method of bimaxillary orthognathic surgery planning and model surgery based on the concept of 6 degrees of freedom (DOF). A 22-year-old man with Class III malocclusion was referred to our clinic with complaints of facial deformity and chewing difficulty. To correct a prognathic mandible, facial asymmetry, flat occlusal plane angle, labioversion of the maxillary central incisors, and concavity of the facial profile, bimaxillary orthognathic surgery was planned. After preoperative orthodontic treatment, surgical planning based on the concept of 6 DOF was performed on a surgical treatment objective drawing, and a Jeon's model surgery chart (JMSC) was prepared. Model surgery was performed with Jeon's orthognathic surgery simulator (JOSS) using the JMSC, and an interim wafer was fabricated. Le Fort I osteotomy, bilateral sagittal split ramus osteotomy, and malar augmentation were performed. The patient received lateral cephalometric and posteroanterior cephalometric analysis in postretention for 1 year. The follow-up results were determined to be satisfactory, and skeletal relapse did not occur after 1.5 years of surgery. When maxillary and mandibular models are considered as rigid bodies, and their state of motion is described in a quantitative manner based on 6 DOF, sharing of exact information on locational movement in 3-dimensional space is possible. The use of JMSC and JOSS will actualize accurate communication and performance of model surgery among clinicians based on objective measurements.

New bimaxillary orthognathic surgery planning and model surgery based on the concept of six degrees of freedom

Jaeho Jeon,Yongdeok Kim,Jongryoul Kim,Heejea Kang,Hyunjin Ji,Woosung Son 대한치과교정학회 2013 대한치과교정학회지 Vol.43 No.1

The aim of this paper was to propose a new method of bimaxillary orthognathic surgery planning and model surgery based on the concept of 6 degrees of freedom (DOF). A 22-year-old man with Class III malocclusion was referred to our clinic with complaints of facial deformity and chewing difficulty. To correct a prognathic mandible, facial asymmetry, flat occlusal plane angle, labioversion of the maxillary central incisors, and concavity of the facial profile, bimaxillary orthognathic surgery was planned. After preoperative orthodontic treatment, surgical planning based on the concept of 6 DOF was performed on a surgical treatment objective drawing, and a Jeon’s model surgery chart (JMSC) was prepared. Model surgery was performed with Jeon’s orthognathic surgery simulator (JOSS) using the JMSC, and an interim wafer was fabricated. Le Fort I osteotomy, bilateral sagittal split ramus osteotomy, and malar augmentation were performed. The patient received lateral cephalometric and posteroanterior cephalometric analysis in postretention for 1 year. The follow-up results were determined to be satisfactory, and skeletal relapse did not occur after 1.5 years of surgery. When maxillary and mandibular models are considered as rigid bodies, and their state of motion is described in a quantitative manner based on 6 DOF, sharing of exact information on locational movement in 3-dimensional space is possible. The use of JMSC and JOSS will actualize accurate communication and performance of model surgery among clinicians based on objective measurements.

Epitaxial Synthesis of Molybdenum Carbide and Formation of a Mo₂C/MoS₂ Hybrid Structure <i>via</i> Chemical Conversion of Molybdenum Disulfide

Jeon, Jaeho,Park, Yereum,Choi, Seunghyuk,Lee, Jinhee,Lim, Sung Soo,Lee, Byoung Hun,Song, Young Jae,Cho, Jeong Ho,Jang, Yun Hee,Lee, Sungjoo American Chemical Society 2018 ACS NANO Vol.12 No.1

<P>The epitaxial synthesis of molybdenum carbide (Mo<SUB>2</SUB>C, a 2D MXene material) <I>via</I> chemical conversion of molybdenum disulfide (MoS<SUB>2</SUB>) with thermal annealing under CH<SUB>4</SUB> and H<SUB>2</SUB> is reported. The experimental results show that adjusting the thermal annealing period provides a fully converted metallic Mo<SUB>2</SUB>C from MoS<SUB>2</SUB> and an atomically sharp metallic/semiconducting hybrid structure <I>via</I> partial conversion of the semiconducting 2D material. Mo<SUB>2</SUB>C/MoS<SUB>2</SUB> hybrid junctions display a low contact resistance (1.2 kΩ·μm) and low Schottky barrier height (26 meV), indicating the material’s potential utility as a critical hybrid structural building block in future device applications. Density functional theory calculations are used to model the mechanisms by which Mo<SUB>2</SUB>C grows and forms a Mo<SUB>2</SUB>C/MoS<SUB>2</SUB> hybrid structure. The results show that Mo<SUB>2</SUB>C conversion is initiated at the MoS<SUB>2</SUB> edge and undergoes sequential hydrodesulfurization and carbide conversion steps, and an atomically sharp interface with MoS<SUB>2</SUB> forms through epitaxial growth of Mo<SUB>2</SUB>C. This work provides the area-controllable synthesis of a manufacturable MXene from a transition metal dichalcogenide material and the formation of a metal/semiconductor junction structure. The present results will be of critical importance for future 2D heterojunction structures and functional device applications.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2018/ancac3.2018.12.issue-1/acsnano.7b06417/production/images/medium/nn-2017-064177_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn7b06417'>ACS Electronic Supporting Info</A></P>

The Acquisition of Vocabulary through Negotiated Interaction with AI Chatbots

Jaeho Jeon 한국초등영어교육학회 2020 초등영어교육 Vol.26 No.3

This study explores how learners acquire vocabulary through chatbots according to interactive task type. Two groups were created: 1) the balanced group which performed a responsive interaction task and a proactive interaction task and 2) the input-based group which only performed two responsive interaction tasks. During the responsive interaction task, learners took on the role of target word receiver while interacting with a chatbot. For the proactive interaction task, the roles of chatbot and learner were reversed. Based on the topic “Where is the post office?”, an interactive chatbot was designed, learner and chatbot interaction data was analyzed, and the results of the two groups’ post and delayed tests were quantitatively compared in terms of vocabulary acquisition. The following conclusions were drawn. First, different types of negotiation were observed depending on task type. Second, both groups effectively acquired receptive vocabulary knowledge. Lastly, the learners effectively acquired productive vocabulary knowledge. The balanced group outperformed the input-based group in the acquisition of productive knowledge because the output element for target vocabulary in the proactive task affected its effectiveness. This study shows the potential for chatbots to be used as learning tools for vocabulary acquisition as well as speaking or writing practice tools.

Chatbot Affordances in the EFL Classroom

Jaeho Jeon 한국영어교육학회 2022 KATE Forum Vol.46 No.1

Controlling Grain Size and Continuous Layer Growth in Two-Dimensional MoS₂ Films for Nanoelectronic Device Application

Jeon, Jaeho,Jang, Sung Kyu,Jeon, Su Min,Yoo, Gwangwe,Park, Jin-Hong,Lee, Sungjoo IEEE 2015 IEEE TRANSACTIONS ON NANOTECHNOLOGY Vol.14 No.2

<P>We report that control over the grain size and lateral growth of monolayer MoS2 film, yielding a uniform large-area monolayer MoS2 film, can be achieved by submitting the SiO2 surfaces of the substrates to oxygen plasma treatment and modulating substrate temperature in chemical vapor deposition (CVD) process. Scanning electron microscopy and atomic force microscopy images and Raman spectra revealed that the MoS2 lateral growth could be controlled by the surface treatment conditions and process temperatures. Moreover, the obtained monolayer MoS2 films showed excellent scalable uniformity covering a centimeter-scale SiO2/Si substrates, which was confirmed with Raman and photoluminescence mapping studies. Transmission electron microscopy measurements revealed that the MoS2 film of the monolayer was largely single crystalline in nature. Back-gate field effect transistors based on a CVD-grown uniform monolayer MoS2 film showed a good current on/off ratio of similar to 10(6) and a field effect mobility of 7.23 cm(2)/V.s. Our new approach to growing MoS2 films is anticipated to advance studies of MoS2 or other transition metal dichalcogenide material growth mechanisms and to facilitate the mass production of uniform high-quality MoS2 films for the commercialization of a variety of applications.</P>

Effect of the Laser-Scribing on Spalling of a Single Crystalline Si Using Electrodeposition Assisted Stripping (EAS) Process

Jeon, Jaeho,Yu, Sungkuk,Yang, Changyol,Jin, Sanghyun,Roh, Jiwon,Jung, Jaehak,Yoo, Bongyoung American Scientific Publishers 2016 Journal of Nanoscience and Nanotechnology Vol.16 No.10

<P>The single crystalline Si comprises a large proportion of the solar cell overall cost. Lowering its cost is directly related to the cost-reduction in the solar cell. Previously, electrodeposition assisted stripping (EAS) process was employed to obtain a thin Si substrate by applying the high tensile stress on top of Si wafer, which induced the delaminating behavior of thin Si layer. Such a high stress can induce by depositing a Ni layer onto the Si substrate. This stripping phenomenon occurred at the position where the maximum shear stress is applied, which is not on the Si surface but at a certain distance below the Si surface. This research aims to precisely control the initiation point of stripping the thin Si layer by generating intentional micro-cracks on the side of Si wafer. The pre-crack was created by a laser scribing on the side of Si wafer. Also, the process parameters which affected the thickness of stripped Si layer were systematically investigated.</P>

Layer-controlled CVD growth of large-area two-dimensional MoS2films

Jeon, Jaeho,Jang, Sung Kyu,Jeon, Su Min,Yoo, Gwangwe,Jang, Yun Hee,Park, Jin-Hong,Lee, Sungjoo The Royal Society of Chemistry 2015 Nanoscale Vol.7 No.5

<P>In spite of the recent heightened interest in molybdenum disulfide (MoS2) as a two-dimensional material with substantial bandgaps and reasonably high carrier mobility, a method for the layer-controlled and large-scale synthesis of high quality MoS2 films has not previously been established. Here, we demonstrate that layer-controlled and large-area CVD MoS2 films can be achieved by treating the surfaces of their bottom SiO2 substrates with the oxygen plasma process. Raman mapping, UV-Vis, and PL mapping are performed to show that mono, bi, and trilayer MoS2 films grown on the plasma treated substrates fully cover the centimeter scale substrates with a uniform thickness. Our TEM images also present the single crystalline nature of the monolayer MoS2 film and the formation of the layer-controlled bi- and tri-layer MoS2 films. Back-gated transistors fabricated on these MoS2 films are found to exhibit the high current on/off ratio of 10(6) and high mobility values of 3.6 cm(2) V(-1) s(-1) (monolayer), 8.2 cm(2) V(-1) s(-1) (bilayer), and 15.6 cm(2) V(-1) s(-1) (trilayer). Our results are expected to have a significant impact on further studies of the MoS2 growth mechanism as well as on the scaled layer-controlled production of high quality MoS2 films for a wide range of applications.</P>

민주화 이후 한국 민족주의의 변화

전재호(Jeon, Jaeho) 서강대학교 현대정치연구소 2012 현대정치연구 Vol.5 No.1

CPS 기반 디지털 트윈 모델링 및 시뮬레이션 기술

전재호(Jaeho Jeon),강성주(Sungjoo Kang),정성일(Sungil Jeong),전인걸(Ingeol Chun) 대한산업공학회 2018 대한산업공학회 춘계학술대회논문집 Vol.2018 No.4

최근 ICT 기술의 발전을 통한 생산시스템의 디지털화는 제조 페러다임을 변화시키고 "디지털 트윈"이라는 새로운 개념을 제시하고 있다. 제조생산시스템은 크게 IT(Information Technology) Systems와 OT(Operation Technology) Systems로 구분이 되는데, 디지털 트윈의 등장으로 제조 라이프사이클 전반에 걸쳐 정교하고 정확한 모델(Model)을 만드는 작업은 매우 중요하게 대두되고 있다. 본 논문에서는 디지털 트윈 구현을 위한 CPS 기반 디지털트윈 모델링 및 시뮬레이션 기술을 제시한다. The recent digitization of production system through the development of ICT technology changes the manufacturing paradigm and suggests a new concept called "digital twin". Manufacturing production systems are divided into Information Technology (IT) Systems and Operation Technology (OT) Systems. The emergence of digital twinning makes it very important to create sophisticated and accurate models throughout the manufacturing lifecycle have. In this paper, CPS based digital twin modeling and simulation technology for digital twin implementation is presented.