Thickness-dependent Ferroelectric Behaviors of (111)-Textured Polycrystalline Pseudo-cubic BiFeO3 Thin Films

최해인,김상욱,도달현,김상수,김원정,Myang Hwan Lee,박진수,조형준,김다정,조종호,송태권 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.2

Preferentially (111)-textured polycrystalline BiFeO3 (BFO) thin films with different thicknesses were deposited on Pt(111)/Ti/SiO2/Si(100) substrates by using a pulsed laser deposition method. The structure of the BFO films was found to be pseudo-cubic with a lattice constant of 3.96 °A based on the X-ray diffraction analysis. The (111)-textured polycrystalline BFO films exhibited good square-type P-E loops with a relatively large remnant polarization (2Pr) of 41 54 μC/cm2and a coercive field (2Ec) of 470 510 kV/cm at an applied electric field strength of ±460 kV/cm. Even though the thicknesses of the films were changed, the changes in 2Pr and 2Ec were relatively small. The enhanced leakage current densities of the polycrystalline BFO films were observed to be at least comparable with those of other epitaxial BFO films. Furthermore, the leakage current densities of the films improved with increasing thickness. Preferentially (111)-textured polycrystalline BiFeO3 (BFO) thin films with different thicknesses were deposited on Pt(111)/Ti/SiO2/Si(100) substrates by using a pulsed laser deposition method. The structure of the BFO films was found to be pseudo-cubic with a lattice constant of 3.96 °A based on the X-ray diffraction analysis. The (111)-textured polycrystalline BFO films exhibited good square-type P-E loops with a relatively large remnant polarization (2Pr) of 41 54 μC/cm2and a coercive field (2Ec) of 470 510 kV/cm at an applied electric field strength of ±460 kV/cm. Even though the thicknesses of the films were changed, the changes in 2Pr and 2Ec were relatively small. The enhanced leakage current densities of the polycrystalline BFO films were observed to be at least comparable with those of other epitaxial BFO films. Furthermore, the leakage current densities of the films improved with increasing thickness.

Treacher Collins 증후군 환아의 기관 삽관 시 마우스가드의 활용

최해인,최병재,최형준,송제선,이제호 大韓小兒齒科學會 2014 大韓小兒齒科學會誌 Vol.41 No.1

Treacher Collins syndrome (TCS) is autosomal dominant disorder that occurs approximately 1 in 25,000 to50,000 live births. The main signs of syndrome are hypoplasia of facial bone and microtia. One in third of themis associated with cleft palate and often shows dental hypoplasia. TCS patients need several number of surgerywith general anesthesia throughout their life time for recovery of function and esthetic. Endotracheal intubationof TCS patient is very difficult due to microstomia, retrognathia, choanal stenosis, and decreased oropharyngealairway. Therefore, general anesthesia of adolescent TCS patient with immature incisor roots has high risk ofcausing dental trauma. This case is regarding TCS patient who was referred to the Department of PediatricDentistry, Yonsei University for avulsed upper left central incisor during endotracheal intubation. The purposeof this report is to emphasize the usefulness of mouth guard to prevent dental trauma when endotracheal intubationis needed for TCS patient. Treacher collins 증후군(TCS)는 25,000명에서 50,000명당 1명의 빈도로 발생하는 상염색체우성의 유전질환이다. 상, 하악의발육 부전, 부정교합, 양측성 이개 기형, 안검렬의 반몽고증 사면, 구순구개열, 외이도 폐쇄, 중이와 내이의 기형으로 인한 청각 소실등의 구강악안면 부위의 특징을 보여 태생 이후 성인기에 이르기까지 여러 차례에 걸친 외과적 수술을 거치게 된다. 하악골의 형성저하로 하악골이 짧고 후방 위치되며 후방 위치하는 혀와 후비공의 협착과 폐쇄로 인해 상기도가 좁아지게 되는데 이로 인해 기관삽관의 어려움이 따른다. 따라서 치근 발육이 미약한 소아청소년 시기의 TCS 환자의 기관 삽관 시 상악 전치부의 손상 가능성이 매우 높다. 본 증례는 전신마취 유도를 위한 기관 삽관 도중 상악 전치의 완전 탈구가 발생한 TCS 환아의 치험례를 통해 기도 삽관 시사전의 마우스가드 제작의 유용성에 대하여 알리고자 한다.

Treatment of Invasive Candida Osteomyelitis of the Mandible: A Case Report

최해인,오지수,유재식,문성용,최지윤,박현정 대한안면통증∙구강내과학회 2022 Journal of Oral Medicine and Pain Vol.47 No.4

Osteomyelitis in the oral and maxillofacial area is a relatively uncommon inflammatory disease that occurs due to odontogenic causes such as endodontic infection, facial trauma, insufficient blood supply caused by some medical conditions, and iatrogenic postoperative infections. Among them, the incidence rate of candida osteomyelitis in this area is minimal; therefore, no consensus on the diagnosis, treatment, and prognosis has not been established yet. With the increasing number of immunocompromised elderly patients, candida osteomyelitis of the jaw is expected to become more prevalent. In this case report, we present an 81-year-old male patient with candida osteomyelitis of the jaw, including the maxillary and ethmoid sinuses.

Treatment of Central Hemangioma with Embolization in the Mandible

최해인,김경윤,신동호,오지수,문성용,You Jae-Seek,유지원 대한안면통증∙구강내과학회 2023 Journal of Oral Medicine and Pain Vol.48 No.4

Hemangioma is a lesion characterized by vascular proliferation of endothelial origin, manifesting neoplastic features. The occurrence of central hemangioma in the oral and maxillofacial region is exceptionally rare, and in two-thirds of cases, it is predominant in the mandible rather than the maxilla. The main symptoms and signs associated with central hemangiomas include pulsation, bone expansion, bruit, teeth displacement, and root resorption of the adjacent teeth. Bleeding may manifest periodically from the sulcus surrounding the affected teeth, particularly when accompanied by hypermobility in the primary dentition. One of the most noteworthy complications is the potential for severe bleeding during tooth extraction or surgical procedures conducted in proximity to unrecognized hemangiomas. Such situations may pose a life-threatening risk. Taking this into consideration, we present two cases of central hemangiomas in adolescent patients who sought consultation, with subsequent embolization performed by the Department of Radiology in Chosun University Hospital.

하악 전치부 상실로 인한 조음장애를 보이는 경도 지적장애 환아에서 탄성의치를 통한 조음능력의 향상

최해인,최병재,최형준,송제선,이제호,Choi, Haein,Choi, Byungjai,Choi, Hyungjun,Song, Jeseon,Lee, Jaeho 대한소아치과학회 2013 大韓小兒齒科學會誌 Vol.40 No.4

구강악안면의 여러 구조는 매우 복잡하고 정밀한 상호과정을 거쳐 말소리를 만들어낸다. 그 중 치아는 중요한 조음기관으로서 치아의 상실시 정상적인 발음을 하기 위해서는 혀와 턱의 위치 수정을 통한 적응이 필요하며, 적응 가능 범위를 벗어난 경우에는 적극적인 보철적, 교정적 치료를 요하게 된다. 소아의 다수 치아 상실은 조음에 어려움을 가져올 뿐만 아니라 부정교합, 악골발육 저하, 측두하악관절의 변위, 저작력 저하, 영양 불균형, 심미성 저하 등의 문제를 초래하기 때문에 반드시 상실부위의 회복이 필요하다. 아크릴릭 레진을 이용한 기존의 가철성 장치와 비교하여 Valplast$^{(R)}$ 탄성의치는 조직과 긴밀하기 접착되며 치은의 자연적인 색조를 투과시키는 얇고 강한 레진 유지부를 가져 심미성이 매우 높으며 우수한 물성을 가지는 등 많은 장점을 갖고 있다. 특히 전체적인 두께가 얇고 부피가 작아 이물감이 적고 혀의 움직임을 방해하지 않기 때문에 발음의 회복에 장점을 가진다. 본 증례는 완전탈구된 하악 전치부로 인해 조음장애를 보였으나 Valplast$^{(R)}$ 탄성의치를 장착한 후 조음의 개선을 보인 경도 지적장애 환아에 관한 것으로 조음검사를 통해 하악 전치부의 상실이 조음에 미치는 영향에 보고하고자 한다. Speech is complex psycho-physiological mutual process which includes many orofacial organs. Especially, teeth play an especially important role as an articulation organ in conjunction with the lips and tongue. When teeth are missing, the position of tongue and mandible is adjusted to produce correct sound. If a patient's adaptive function is inadequate for modification of malocclusion, prosthodontic and orthodontic interventions are necessary. Missing teeth of young patients should be reconstructed bacause it can cause malocclusion, decreased masticatory efficiency, articulation disorders, esthetic problem, and temporomandibular disorder. Valplast$^{(R)}$(Valplast International Corp, New York, USA) flexible denture is useful for rehabilitation due to its excellent physical properties, esthetics, and small volume. This case is regardingan intellecturally disabled patient with anarticulation disorder caused by missing lower incisors due to trauma. The patient showed improvement in articulation by using flexible partial denture. The purpose of this report is to figure out the influence of missing lower anterior teeth on articulation.

다수의 과잉 소구치를 가진 정신지체 환자의 치험례

최해인(Hae-in Choi),송제선(Je-Seon Song),이효설(Hyo-Sul Lee),최병재(Byung-Jai Choi),이제호(Jae-Ho Lee) Asia association of Disability and Oral health 2013 대한장애인치과학회지 Vol.9 No.2

과잉 소구치는 장애 환자에서 교정적 문제를 일으켜 구강위생 관리의 어려움을 초래할 수 있는데 발생 시기가 늦고 병리학적 문제의 발생 가능성이 낮으며 재발의 가능성이 높으므로 발거 시기를 전체 영구치열이 완전한 성숙을 이룬 후로 미루어야 하며 매복되어 있어 특이할 만한 합병증이 발견되지 않는 경우, 수술적 위험성을 감수하기보다는 남겨 두는 것을 추천한다. The supernumerary premolars account for 4%-9% of all supernumeraries and reported prevalence is 0.01%-1.00%. Multiple supernumerary teeth can be seen in syndromic phenotypes. But, only 2% of supernumerary premolars exhibited any pathological changes. Most of them cause interference with normal occlusal development that makes maintaining the disabled patients’s oral hygiene difficult. It is recommended to delay the timing of extraction until the full permanent dentition is mature. If there is no complication, leaving the supernumerary premolars impacted is recommended. This case is about mental retardation patients with multiple supernumerary premolars.

ESKAPE Pathogens in Oral and Maxillofacial Infections

이혜정,문성용,오지수,최해인,박상엽,김태은,유재식 대한안면통증∙구강내과학회 2022 Journal of Oral Medicine and Pain Vol.47 No.1

Purpose: Most cases of oral and maxillofacial infections are usually easily treated by proper diagnosis, elimination of causative factors, and antibiotic therapy. However, the emergence and the increase of multidrug-resistant bacteria make treatment challenging. “ESKAPE” pathogens are the most common opportunistic organisms in nosocomial infections and have resistant to commonly used antibiotics. There are many medical reviews of ESKAPE pathogens, but few in dentistry. This study focuses on oral and maxillofacial infection especially with ESKAPE pathogens. The purpose of this study is to prepare feasible data about tracing and treatment of infection related to pathogens that may be beneficial to clinicians. Methods: A total of 154 patients with oral and maxillofacial infections were reviewed by analyzing retrospectively hospitalized data in the Department of Oral and Maxillofacial surgery, Chosun University Hospital, Korea, past 5 years from January 2014 to December 2018. Based on the medical records and microbiological tests, the results were divided into two groups: infections with ESKAPE pathogens and other bacteria. Results: A total of 22 species were isolated from 154 patients. The proportion of ESKAPE pathogens among all bacterial isolates collected from infected patients was 39.6%. Causative factors, especially in post-operative infection, showed a statistically significant correlation to ESKAPE infections (29 cases). And average of treatment period in ESKAPE group was longer than non-ESKAPE groups. Overall, Klebsiella pneumoniae (60.7%) was the most frequently isolated ESKAPE pathogen. And high antibiotic resistance rates had been detected in the ESKAPE during the five-year period. Conclusions: Infections with ESKAPE pathogens are now a problem that can no longer be overlooked in Dentistry. Based on results of this study, ESKAPE pathogens were highly associated with post-operative or opportunistic infections. Clinicians should be careful about these antibiotic resistant pathogens and use appropriate antibiotics to patients while having dental treatments.

우수한 압전 특성과 고온 상전이 온도를 가지는 BiAlO3 를 첨가한 BiFeO3-BaTiO3 세라믹

조형래,이명환,김다정,최해인,김원정,정성수,송태권 한국물리학회 2021 새물리 Vol.71 No.3

[1 - x]Bi1:03(Fe0:99Al0:01)O3-xBaTiO3 (x = 0.30, 0.33, 0.35, and 0.40) lead-free piezoelectric ceramics were prepared through a conventional solid-state reaction method followed by a waterquenching process. A single perovskite structure without any impurity or secondary phase was confirmed for all compositions. The crystal phase, phase transition, microstructure, dielectric, ferroelectric, and piezoelectric properties were investigated. The temperature-dependent dielectric losses (tan ) were found to decrease dramatically to 100 – 200 ◦C and then increased sharply at higher temperatures for x = 0.30, 0.33, and 0.35. The ferroelectric properties improved with increasing measurement temperatures and the highest value of 2Pr = 80.2 C/cm2 was observed at x = 0.33 at 100 ◦C. It was found that the best piezoelectric charge sensor coefficient (d33) was 323 pC/N and the Curie temperature (TC) was 452 ◦C for x = 0.33. The best piezoelectric actuator coefficient (d 33) was 515 pm/V and the TC was 344 ◦C for x = 0.40. These results showed that Al-doped BF-BT ceramics have great potential for were in high-temperature lead-free piezoelectric sensor and actuator applications. [1 - x]Bi1:03(Fe0:99Al0:01)O3-xBaTiO3 (x = 0.30, 0.33, 0.35, 그리고 0.40)의 고용체에 1 mol%의BiAlO3 를 첨가물로 사용하여 일반적인 고상반응법을 이용하여 소결한 후 물을 이용한 급속냉각법으로압전 세라믹을 제작하였다. 각 조성의 결정구조, 상전이, 미세구조, 유전, 강유전 및 압전특성을 조사하였다. 모든 조성에서 불순물 혹은 이차상 없이 단일 페로브스카이트 구조의 상을 가졌다. x = 0.30, 0.33, 0.35 조성에서 측정 온도에 따라 유전손실 (tan ) 값이 100 - 200 ◦C에서 급격히 감소되고 다시 증가되었다. 강유전 이력곡선 측정결과 100 ◦C에서 x = 0.33 조성이 가장 높은 잔류분극 2Pr = 80.2 C/cm2 을가졌다. x = 0.33 조성은 가장 높은 정압전 상수d33 = 323 pC/N와 452 ◦C의 상전이 온도(TC)를 가졌다. 또한, x = 0.40 조성에서 가장 높은 역압전 상수 d 33 = 515 pm/V와 TC = 344 ◦C의 값을 가지는 것을확인하였다. 이 결과로부터 Al을 첨가물로 사용한 비납계 압전체 BF-BT는 고온용 센서 및 액추에이터소자로 활용될 수 있는 가능성이 높다는 것을 보였다.

Deep Neck Infection Caused by Infected Dentigerous Cyst: A Case Report

김경미,오지수,유재식,문성용,최해인 대한안면통증∙구강내과학회 2021 Journal of Oral Medicine and Pain Vol.46 No.4

Deep neck infection (DNI) is a potentially serious pathology that can lead to serious complications and high rate of mortality. Since DNI affects the cervical spaces, which can compromise airway, aggressive antibiotic administration and prompt surgical drainage are essential for recovery. Although most causes of DNI are known to be dental infections, developmental cysts such as dentigerous cysts are relatively few causes. In this case, we report a rare patient with severe deep neck space infection caused by infected third molar with dentigerous cyst.

인천의 여성성과 도시 정체성에 관한 연구

구영민(Koo, Young-Min),최해인(Choi, Hae Ahn) 인천대학교 인천학연구원 2005 인천학연구 Vol.4 No.-

The study attempts to discover the geographical and spatial significance of Incheon city through decoding the void come out of the social, physical, psycho-cultural collisions in the modern city, to grasp the urban characteristics of Incheon through scrutinizing into a movie based on the discourse strategy, and to investigate a selected site, Buk-Sung Dong, to investigate the feminacy inherent in Incheon city. This study investigates the city of Incheon on the basis of its natures: as a modern metropolis and as indigenous geography. The discussion in this paper focuses on urban discourse leading to the idea of “the third city” that rather embraces and respects all aspects of Incheon than unifies them. Then, the inquiry furthers into the ‘third space’ that constructs the third city and that includes not only innovative, hybrid, and translative identity but also negotiatory of differences and perimeter-being. The study takes the discourse as a hypothetical strategy to read the urban characteristics of Incheon. The movie. “Take Care My Cat” will be introduced in order to detect the others' feminacy inherent in the city of Incheon through scrutinizing the discourse strategy utilized in the movies with regard to the view of post-feminism. The study then attempts to re-interpret the city of incheon on the basis of above analysis, to reflect the femmage technic invented by Miriam Schapiro, a feminist-artist, and finally to propose an innovative theory of ‘Femmage City’ as a concrete discourse strategy that is to e utilized to read between the lines in the modern city, Incheon.