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.

Chatbot Affordances in the EFL Classroom

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

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>

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>

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.

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 '보수' 정부의 대북정책 연구

전재호(JEON Jaeho, 全宰鎬) 신아시아연구소(구 신아세아질서연구회) 2013 신아세아 Vol.20 No.2

이 글은 민주화 이후 보수정부로 간주되는 노태우, 김영삼, 이명박 정부의 대북 인식과 정책을 비교 분석했다. 노태우 정부는 냉전 종식을 기반으로 남북기본합의서라는 남북 정부 간 최초의 공식 합의를 이끌어냈다. 노태우 정부는 비록 보수 정부였지만 민족 중심적 시각을 견지했기 때문에 이것이 가능했다. 그러나 후임 김영삼 정부는 초기에는 민족 중심적 시각에서 대북정책을 전개했지만 북한의 핵 개발과 김일성 주석의 사망을 계기로 다시 권위주의 시기의 적대적인 대북정책으로 회귀했다. 10년 후 등장한 이명박 정부는 국가 중심적 시각에서 전임 김대중, 노무현 정부의 대북화해정책에 반대했고 '상생ㆍ공영의 정책'이라는 적대적 대북정책을 전개했다. 또한 북한이 핵, 미사일을 개발하고 남북 간의 무력충돌이 발발하자 이명박 정부는 더욱 강경한 대북정책을 전개했다. 이렇게 같은 보수정부였지만 민주화 이후 세 정부의 대북인식과 정책은 상이한 모습을 띠었다. 이는 국제정세를 포함하여 각 정부가 처한 시대적 환경과 북한의 대응에 기인한 것이지만 지도자의 대북인식과 그에 따른 정책적 판단 역시 상당히 중요하다는 사실을 보여준다. 결국 이상의 고찰을 통해 우리는 남북관계의 개선에는 북한에 대한 적대적 인식과 대결 정책보다 대화와 타협을 통한 상호신뢰 구축이 보다 필요하다는 교훈을 얻을 수 있다. This article analyzes and compares three "conservative" post-democratization South Korean governments' attitudes and policies towards the North. The Roh Tae-woo government achieved the first official agreement between the South and North, called "the South-North Basic Agreement" in the midst of a post-Cold War environment. Although conservative, the Roh Tae-woo government was able to accomplish this because it maintained a nation-centered perspective towards the South-North relationship. The Kim Young-sam government adopted the same nation-centered policies towards the North in the beginning. However, it returned to more antagonistic policies of the pre-democratization authoritarian regimes when the North began developing its nuclear program and North Korea 's leader at the time. Kim II-sung, died. From the very outset, the Lee Myung-bak government opposed the reconciliation-centered policies of his predecessors, Kim Dae-jung and Roh Moo-hyun, and adopted antagonistic policies towards the North under the banner of a "Policy of Mutual Benefits and Common Prosperity." These antagonistic policies intensified after the North developed nuclear missiles and armed conflicts between the South and the North began again. In summary, although the above three post- democratization governments were all essentially conservative in nature. the particulars of each of their policies towards the North were very different. This was primarily due to the international climate at the time as well as the policies of North Korea. Additionally, South Korean presidents' attitudes played an important role in their governments' different approaches and policies. This study also suggests that policies of dialogue and reconciliation rather than those of antagonism and confrontation can contribute better to building trust and improved relations between both parties.

해방 후 단군 인식의 변화에 관한 연구: 단군 민족주의의 약화와 국수주의의 확산

전재호 ( Jaeho Jeon ) 경남대학교 극동문제연구소 2021 한국과 국제정치 Vol.37 No.4

이 글은 20세기 초 한국에서 민족적 상징으로 등장한 단군에 대한 인식이 해방 후 어떻게 변화했는지, 특히 왜 단군 민족주의가 약화하고 국수주의가 확산했는지를 고찰했다. 일제 강점기 독립운동에 정당성을 부여했던 단군 민족주의는 해방 후 남북통일에 정당성을, 그리고 대한민국에 민족 정통성을 부여하는 역할을 했다. 정부 수립 직후 단군 연호, 개천절, 홍익인간 교육이념 채택이 이를 보여준다. 그런데 1960년대부터 단군 민족주의는 변화하기 시작했다. 단군 관련 종교단체가 쇠퇴하고, 기독교를 중심으로 단군 민족주의에 대한 이견이 표출되었으며, 시대적 과제가 변함에 따라 민족적 상징의 역할도 축소되었다. 이에 비해, 단군을 앞세운 재야사학자들은 기성 역사학계를 식민사관이라고 비판하고 단군조선을 ‘황금시대’로 포장하여 국수주의를 조장하며 세력을 확대했다. 그러나 이러한 국수주의는 기존 단군 민족주의의 흐름에서 완전히 이탈한 행보였다. 21세기 단군 민족주의는 매우 약화했지만, 통일이라는 민족적 과제가 부상할 경우, 제한적이지만 상징적 역할을 할 것으로 예상된다. This paper aims to study how South Korean attitudes toward Dangun, the legendary founding father of the Korean nation, who emerged as a symbol of the nation in the early 20^th century, changed after liberation in 1945. In particular, I examine how nationalism centered on Dangun weakened during this period, while chauvinism has spread more widely. Dangun-centered nationalism, which acted as a justification for the Korean independence movement during the Japanese colonial period, was subsequently used to validate the task of national unification and to legitimize the South Korean government, immediately after its establishment in 1948. This was exemplified in the fact that the South Korean government briefly adopted Dangun as its era name, while also establishing National Foundation Day on the day Dangun was supposed to have founded Korea and adopting Dangun’s humanitarian ideal as its educational ideology. This attitude toward Dangun began changing in the 1960s, however, as the division of the country settled in: Opinions differing from this attitude were widely expressed and religious organizations related to Dangun worship declined. In contrast, independent historians who focused more intensively on Dangun continued to expand their influence in society. They criticized established historiography as contaminated by colonialism, while also encouraging an attitude of chauvinism, embellishing the period of Dangun Joseon as a golden era. This attitude broke away entirely from the previous nationalist trend in which Dangun played the role of a symbol of the nation, as meeting the particular needs of the times. In the 21^st century, Dangun-centered nationalism has lost most of its previous importance; however, we anticipate that it could again play a limite