학생들이 사용한 엔진 구동형 Ni-Ti file systems의 근관 성형 효율 비교

강문성,김현철,허복,박정길 大韓齒科保存學會 2006 Restorative Dentistry & Endodontics Vol.31 No.1

본 연구의 목적은 학생들이 사용한 세 가지 Ni-Ti 파일의 성형효율을 비교하고, 각 파일의 사용 경험 유무에 따른 차이를 비교하여 치과대학생을 위한 교육에 적합한 종류를 선택하는데 도움을 얻고자하는 것이다. Ni-Ti 파일 사용 경험이 없는 학생 50명과 Ni-Ti 파일을 사용한 근관치료 경력이 2년 이상인 경험자 10명이 세 종류의 Ni-Ti file - ProFile^(®) (PF), HeroShaper^(®) (HS), K3™ (K3) -을 사용하여 180개의 근관 모형을 성형하였다. 근관성형 시간 및 기구 변형, 근관 이형성을 조사하고 성형 전후 상을 중첩하여 근관 삭제폭, 근관변위량과 중심변위율을 1, 3, 5 ㎜에서 분석하였다. 1. 근관 성형시간은 HS군이 가장 빨랐으며, 총 삭제량은 모든 지점에서 K3군이 다른 군보다 컸다 (P<0.05). 2. 세 군 모두 1, 3 ㎜에서 외측 변이를 보였고, 1 ㎜ 지점에서 PF군이 가장 안정적이었다 (P< 0.05). 3. 중심변위율은 1, 3 ㎜에서 HS, PF군이 K3군보다 작았다. 5 ㎜ 지점에서 PF군이 가장 작았고, PF군 3 ㎜에서 학생은 경험자보다 유의하게 작았다 (P < 0.05). The purpose of this study was to compare the shaping ability of three Ni-Ti file systems used by dental students or the experts and consequently to aid in choosing a proper systems for educational courses of dental students and beginners. Fifty students and ten dentists who have clinical experience over two years prepared 180 simulated root canals in resin blocks with three Ni-Ti systems: ProFile^(®) (PF), HeroShaper^(®) (HS), K3™ (K3). After preparation, the Ni-Ti files were evaluated for distortion and canal preparation time was recorded. The images of pre- and post-instrumented canals were scanned and superimposed. Amounts of increased canal widths,deviation, and centering ratio were calculated at apical 1, 3 and 5 ㎜ levels and statistical analysis was performed. The results were as follows: 1. HS showed the shortest preparation time and instrumented canal width in K3 was significantly larger than other groups (P< 0.05). 2. At 1 and 3 ㎜ levels, all groups had outward deviation. In student group, at the 1 ㎜ level, PF had the least deviation (P< 0.05). 3. In the centering ratio, the PF had the best centering ability compared to the others at 5 ㎜ level. At 1 and 3 ㎜ level, HS and PF had better abilities than K3. Student group had better ratio than the expert at 3 ㎜ level with PF (P<0.05). Based on the results, it is surmised that the ProFile^(®) is the safest and most ideal instrument for students and beginners.〔J Kor Acad Cons Dent 31(1):1-10, 2006〕

Semiconductor–Insulator–Semiconductor Diode Consisting of Monolayer MoS₂, h-BN, and GaN Heterostructure

Jeong, Hyun,Bang, Seungho,Oh, Hye Min,Jeong, Hyeon Jun,An, Sung-Jin,Han, Gang Hee,Kim, Hyun,Kim, Ki Kang,Park, Jin Cheol,Lee, Young Hee,Lerondel, Gilles,Jeong, Mun Seok American Chemical Society 2015 ACS NANO Vol.9 No.10

<P>We propose a semiconductor–insulator–semiconductor (SIS) heterojunction diode consisting of monolayer (1-L) MoS<SUB>2</SUB>, hexagonal boron nitride (h-BN), and epitaxial p-GaN that can be applied to high-performance nanoscale optoelectronics. The layered materials of 1-L MoS<SUB>2</SUB> and h-BN, grown by chemical vapor deposition, were vertically stacked by a wet-transfer method on a p-GaN layer. The final structure was verified by confocal photoluminescence and Raman spectroscopy. Current–voltage (<I>I</I>–<I>V</I>) measurements were conducted to compare the device performance with that of a more classical p–n structure. In both structures (the p–n and SIS heterojunction diode), clear current-rectifying characteristics were observed. In particular, a current and threshold voltage were obtained for the SIS structure that was higher compared to that of the p–n structure. This indicated that tunneling is the predominant carrier transport mechanism. In addition, the photoresponse of the SIS structure induced by the illumination of visible light was observed by photocurrent measurements.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2015/ancac3.2015.9.issue-10/acsnano.5b04233/production/images/medium/nn-2015-042335_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn5b04233'>ACS Electronic Supporting Info</A></P>

Electrochemical Synthesis of Graphene/MnO₂ Nano-Composite for Application to Supercapacitor Electrode

Jeong, Kwang Ho,Lee, Hyeon Jeong,Simpson, Michael F.,Jeong, Sang Mun American Scientific Publishers 2016 Journal of nanoscience and nanotechnology Vol.16 No.5

<P>Graphene/MnO2 nano-composite was electrochemically synthesized for application to an electrode material for electrochemical supercapacitors. The nanosized needle-like MnO2 was obtained by use of a graphene substrate. The prepared composite exhibited an ideal supercapacitive behavior. A capacitance retention of 94% was achieved with a 4 h deposition time (an initial capacitance of 574 mF/cm(2) at a scan rate of 20 mV/s) and the retention declined with further deposition time. The results demonstrate enhanced contact between the electrode and electrolyte and improved power density as an electrochemical capacitor.</P>

A new mid-late maturing japonica rice variety Hyeonpum with a good grain quality and eating quality

Jeong-Ju Kim,Woon-Chul Shin,Mun-Sik Shin,Ki-Yeong Kim,Bo-Kyeong Kim,Jeong-Kwon Nam,Jong-Cheol Ko,Hyeon-Su Park,Ki-Yong Ha,Man-Kee Baek,So-Hyeon Baek,Young-Jun Mo,Woo-Jae Kim,Hyeon-Jung Kang,Jae-Kwon K 한국육종학회 2013 한국육종학회 심포지엄 Vol.2013 No.07

‘Hyeonpum’ is a new japonica rice variety developed by a cross breeding between Iksan469 having a good canopy architecture and Sindongjin and Musashino 7 having a good eating-quality with a view to develop a new variety having high quality of grain and palatability by the rice breeding team of Rice Breeding and Cultivation Research Division, Department of Rice and Winter Cereal Crop, NICS, RDA in 2012. The heading date of this variety is August 18 and later than that of check variety, Nampyeongbyeo, by four days. ‘Hyeonpum’ has 74cm of culm length and 101 spikelets per panicle. This variety showed resistance to bacterial leaf blight and rice stripe virus, but susceptible to leaf blast and planthoppers. The milled rice of this variety exhibits translucent and very clear non-glutinous endosperm. ‘Hyeonpum’ has much better palatability of cooked rice than that of Nampyeongbyeo. The whole grain rate of milled rice and milled rice recovery of ‘Hyeonpum’ are slightly higher than those of Nampyeongbyeo as 91.8% and 75.2% respectively. The yield of ‘Hyeonpum’ is 5.6 MT/ha in milled rice. ‘Hyeonpum’ could be adaptable to the southern part plain area of Pyeongtaek and southwestern costal areas in Korea.

Metal–Insulator–Semiconductor Diode Consisting of Two-Dimensional Nanomaterials

Jeong, Hyun,Oh, Hye Min,Bang, Seungho,Jeong, Hyeon Jun,An, Sung-Jin,Han, Gang Hee,Kim, Hyun,Yun, Seok Joon,Kim, Ki Kang,Park, Jin Cheol,Lee, Young Hee,Lerondel, Gilles,Jeong, Mun Seok American Chemical Society 2016 NANO LETTERS Vol.16 No.3

<P>We present a novel metal-insulator-semiconductor (MIS) diode consisting of graphene, hexagonal BN, and monolayer MoS2 for application in ultrathin nano electronics. The MIS heterojunction structure was fabricated by vertically stacking layered materials using a simple wet chemical transfer method. The stacking of each layer was confirmed by confocal scanning Raman spectroscopy and device performance was evaluated using current versus voltage (I-V) and photocurrent measurements. We clearly observed better current rectification and much higher current flow in the MIS diode than in the p-n junction and the metal-semiconductor diodes made of layered materials. The I-V characteristic curve of the MIS diode indicates that current flows mainly across interfaces as a result of carrier tunneling. Moreover, we observed considerably high photocurrent from the MIS diode under visible light illumination.</P>

The Factors Associated with Contact Burns from Therapeutic Modalities

Jeong-Hyeon Mun,서정훈,Jong-Hyun Jeon,Yun-Jae Jung,장기언,양형태,임해준,조용석,김도헌,허준,김종현,전욱 대한재활의학회 2012 Annals of Rehabilitation Medicine Vol.36 No.5

Objective To understand the injury pattern of contact burns from therapeutic physical modalities.Method A retrospective study was done in 864 patients with contact burns who discharged from our hospital from January 2005 to December 2008. The following parameters were compared between patients with contact burns from therapeutic modalities and from other causes: general characteristics, burn extent, cause of burn injury, place of occurrence, burn injury site, treatment methods, prevalence of underlying disease, and length of hospital stay were compared between patients with contact burns. Results Of the 864 subjects, 94 patients were injured from therapeutic modalities. A hot pack (n=51) was the most common type of therapeutic modality causing contact burn followed by moxibustion (n=21), electric heating pad (n=16), and radiant heat (n=4). The lower leg (n=31) was the most common injury site followed by the foot & ankle (n=24), buttock & coccyx (n=9), knee (n=8), trunk (n=8), back (n=6), shoulder (n=4), and arm (n=4). Diabetes mellitus was associated with contact burns from therapeutic modalities; the odds ratio was 3.99. Injuries took place most commonly at home (n=56), followed by the hospital (n=33), and in other places (n=5). Conclusion A hot pack was the most common cause of contact burns from therapeutic modalities, and the lower leg was the most common injury site. Injuries took place most commonly at home. The patients with contact burns from therapeutic modalities showed high correlation to presence of diabetes mellitus. These results would be helpful for the prevention of contact burns due to therapeutic modalities.

도메인 온톨로지를 이용한 개인화된 개념기반 검색 기법

문현정(Mun Hyeon Jeong),이수진(Lee Soo Jin),김영지(Kim Young Ji),우용태(Woo Yong Tae) 한국전자거래학회 2007 한국전자거래학회지 Vol.12 No.3

본 논문에서는 도메인 온톨로지를 사용하여 개인화된 개념 기반의 검색 기법을 제안하였다. 제안 모델은 도메인 온톨로지를 이용한 컨텐츠의 대표 개념 추출, 컨텐츠 가중치와 개념 가중치를 이용한 사용자 프로파일 구성 그리고 개인화된 개념 기반 검색 과정으로 구성된다. 컨텐츠의 대표 개념은 TScore 기법을 이용하여 추출하였고, 사용자 프로파일은 개인 정보 수집 모듈을 통해 개념 가중치가 높은 개념을 대상으로 구성하였다. 개념 기반 검색을 위해 사용자 프로파일의 개념 집합과 컨텐츠의 대표 개념 집합간에 유사도를 비교하여 개인이 선호하는 개념의 우선순위에 의해 컨텐츠를 검색하였다. 본 논문에서 제안한 기법의 효율성을 검증하기 위하여 인터넷 사이트에서 컨텐츠를 수집하고 사용자 프로파일을 구성하여 실험하였다. 실험 결과, 제안한 검색 기법이 기존의 키워드 기반의 검색 기법에 비해 우수함을 보였다. 제안된 기법은 개인화된 추전 시스템이나 전자 도서관 등과 같은 분야에서 효율적으로 적용할 수 있으리라 기대된다. We propose a personalized concept-based retrieval technique that uses domain ontology. Proposed system consist of representative concept extraction, user profile construction, and concept-based retrieval stages. First, we extract representative concept with using technique form contents and create the domain ontology. We compose user profile analysis that uses domain ontology for personalized concept-based retrieval. To verify the efficiency of the proposed technique, we perform experiment for Internet site in the engineering area. The results of experiment show that the proposed technique using the domain ontology and user profiles is more efficient than the existing techniques. Hence, the proposed concept-based retrieval technique can be expected to contribute to the development of an efficient personalized recommendation system or e-Commerce system.

비만성 저환기 증후군 (Pickwickian 증후군) 3예

정지현 ( Jeong Ji Hyeon ),이상학 ( Lee Sang Hag ),최영미 ( Choe Yeong Mi ),권순석 ( Kwon Sun Seog ),김영균 ( Kim Yeong Gyun ),김관형 ( Kim Gwan Hyeong ),문화식 ( Mun Hwa Sig ),송정섭 ( Song Jeong Seob ),박성학 ( Park Seong Hag 대한결핵 및 호흡기학회 2002 Tuberculosis and Respiratory Diseases Vol.53 No.5

전착법을 이용한 슈퍼커패시터용 다공성 Co(OH)₂ 나노플레이크 박막의 제조 및 전기화학적 특성

이현정 ( Hyeon Jeong Lee ),김은미 ( En Mei Jin ),정상문 ( Sang Mun Jeong ) 한국화학공학회 2016 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.54 No.2

다공성 Co(OH)₂ 나노플레이크 박막은 전위제어 전착법을 이용하여 티타늄 메쉬에 여러 전착전위(-0.75, -1.0, -1.2 및 -1.4 V)에서 전착하여 슈퍼커패시터에 이용하였다. 티타늄 메쉬에 전착된 Co(OH)₂ 나노플레이크 박막의 두께 및 전착량은 전착전위의 제어에 의해 결정되었고 -1.4 V에서 전착한 Co(OH)₂ 나노플레이크 박막의 두께는 약 34 μm로 가장 두껍게 전착되었으며 전착량은 17.2 g이다. 전착전위 -0.75, -1.0, -1.2 및 -1.4 V에서 전착한 경우 초기 방전용량은 각각 226, 370, 720 그리고 1,008 mF cm^{-2}으로 나타났고 1,000 사이클 후 각각 206, 349, 586 그리고 866 mF cm^{-2}으로 나타났다. 또한 이들의 용량유지율은 각각 91, 94, 81 및 86%로 나타났다. Porous Co(OH)₂ nano-flake thin films were prepared by a potential-controlled electro-deposition technique at various deposition voltage (-0.75, -1.0, -1.2, and -1.4 V) on Ti-mesh substrates for supercapacitor application. The potential of electrode was controlled to regulate the film thickness and the amount of Co(OH)₂ nano-flake on the titanium substrate. The film thickness was shown to reach the maximum value of 34 μm at -1.4 V of electrode potential, where 17.2 g of Co(OH)₂ was deposited on the substrate. The specific discharge capacitances were measured to be 226, 370, 720, and 1008 mF cm^{-2} in the 1st cycle corresponding to the films which were formed at -0.75, -1.0, -1.2, and -1.4 V of electrode potentials, respectively. Then the discharge capacities were decreased to be 206, 349, 586 and 866 mF/㎠, where the persistency rates were 91, 94, 81, and 86%, respectively.

대용량 RDF 데이터의 처리 성능 개선을 위한 효율적인 저장구조 설계 및 구현

문현정(Mun Hyeon Jeong),성정환(Sung Jung Hwan),김영지(Kim Young Ji),우용태(Woo Yong Tae) 한국전자거래학회 2007 한국전자거래학회지 Vol.12 No.3

본 논문에서는 대용량 RDF의 효율적인 저장을 위하여 관계 정보와 데이터 정보를 분리한 새로운 방식의 저장 구조를 제안하였다. 제안 방식은 기존의 저장 방식에 비해 데이터의 중복을 최소화하여 대량의 RDF 데이터를 효율적으로 저장할 수 있다. 또한 본 논문에서 제안한 저장 방식을 이용하여 트리플 형태의 관계 정보 릴레이션과 데이터 정보 릴레이션에서 필요한 데이터를 분리 검색하여 결합하는 방식에 의해 RDF 데이터에 대한 질의 성능을 개선할 수 있다. 본 연구 결과는 RDF 데이타를 이용한 전자상거래, 시맨틱 웹, 지식관리 등과 같은 응용 분야에서 대량의 RDF 데이터의 효율적인 관리를 통하여 질의 성능을 개선할 수 있는 기반 기술로 사용할 수 있다. We design and implement an efficient storage technique to improve query processing for a large RDF data set. The proposed techniques can minimize data redundancy compared to the existing techniques by splitting relation information and data information from triple formatted RDF data. Also, we can enhance query processing speed separating and connecting the entire query steps by relation and data based on the proposed storage technique. The proposed technique can be applied to the areas, such as e-Commerce, semantic web, and KMS to store and retrieve a large RDF data set.