Controlled infiltration profile of SiC coating layer on graphite by Si vapor deposition reaction

Kuk-Jin Hwang,Si-Young Bae,Kyoung-Ho Kim,Yoon-Cheol Lee,Jung-Tae Hwang,Heesoo Lee,Seong Min Jeong,Myung-Hyun Lee 한양대학교 세라믹연구소 2019 Journal of Ceramic Processing Research Vol.20 No.2

SiC-coated graphite was successfully fabricated at different temperatures (1300-1600 oC) through a silicon vapor depositionreaction (Si-VDR) process. Si powder was used for the Si source of the SiC coating layers. When Si powder was evaporatedat high temperature near the melting point of bulk Si, Si gases are moved and changed into Si liquid at the surface of thegraphite. The high-temperature process facilitated the formation of SiC coating layers on the graphite. The microstructural,mechanical, and thermal oxidation properties of the coated graphite were investigated.

A Study on Improvement and Degradation of Si/SiO₂ Interface Property for Gate Oxide with TiN Metal Gate

Lee, Byung-Hyun,Kim, Yong-Il,Kim, Bong-Soo,Woo, Dong-Soo,Park, Yong-Jik,Park, Dong-Gun,Lee, Si-Hyung,Rho, Yong-Han The Korean Institute of Electrical and Electronic 2008 Transactions on Electrical and Electronic Material Vol.9 No.1

In this study, we investigated effects of hydrogen annealing (HA) and plasma nitridation (PN) applied in order to improve $Si/SiO_2$ interface characteristics of TiN metal gate. In result, HA and PN showed a positive effect decreasing number of interface state $(N_{it})$ respectively. After FN stress for verifying reliability, however, we identified rapid increase of $N_{it}$ for TiN gate with HA, which is attributed to hydrogen related to a change of $Si/SiO_2$ interface characteristic. In contrast to HA, PN showed an improved Nit and gate oxide leakage characteristic due to several possible effects, such as blocking of Chlorine (Cl) diffusion and prevention of thermal reaction between TiN and $SiO_2$.

폐암과 동반되어 나타난 기관기관지병증 골연골형성증 1예

이영진,전현수,박시형,김모세,김현주,이승헌,이영민,이현욱,이현경 仁濟大學校 白病院 2010 仁濟醫學 Vol.31 No.-

Tracheobronchopathia osteochondroplastica (TPO) is a rare benign disease of unknown etiology characterized by multiple cartilaginous or bony submucosal nodules, which project into the tracheobronchial lumen. Although some disorders were reported combined with TPO, these seemed to be considered casual. We report a case of TPO that combined with adenocarcinoma of lung. She was 50-year-old non smoking woman presented with chronic cough with right chest pain. Lung mass on right lower lobe was found on chest x-ray, so lung cancer was suspected. Multiple scattered whitish small elevations from trachea to bronchial trees were found on bronchoscopic exam. We mistook these lesions for metastases from lung cancer and biopsies of these lesions were done. Transbronchial biopsy for right lower lobe mass lesion was also done. But biopsies from trachea and bronchus revealed TPO rather than lung cancer. Transbronchial lung biopsy of right lower lobe mass was diagnosed adenocarcinoma of lung. So TPO combined with adenocarcinoma of lung was diagnosed.

석탄회분의 융착형성 연구

이시훈,박주식,임영준,김형택 한국화학공학회 1996 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.34 No.1

본 연구에서는 DTF를 이용하여 준역청탄인 Alaska탄의 회분과 deposit을 제조하고 조성을 분석하여 각각의 조성이 용융성에 미치는 영향을 고찰하였으며 ASTM 회분의 결과와 비교하였다. ASTM 회분은 alumina, silica, mullite, Ca-com-pound 등이 결정성으로 존재하는 반면 DTF 회분은 표면에 K, Fe, Ca 등이 농축된 구형의 drop이 만들어지는 것을 알 수 있었다. 또한 DTF 회분에는 mullite만이 결정성으로 존재하였다. Deposit은 용융후 고형화된 glass phase로 만들어 졌는데 Fe는 Fe^(3+) silicate로 전이되고 deposit하부에 Si가 농축되는 것으로부터 석탄 내의 무기물 조성 중에 용융을 지배하는 것은 Si인 것을 알 수 있었다. Alaska탄은 ASTM 회분분석결과로부터는 용융성이 강하게 예측되었으나 DTF에서 형성된 deposit 분석결과 표면에 부착강도를 낮게 하는 Ca가 농축되어 열전달면에서의 제거는 용이한 것으로 판단되었다. Ash and deposits were made using Alaska sub-bituminous coal in a drop tube furnace(DTF) and the effects of their compositions on fusion were compared with those of the ashes prepared from the ASTM aching procedure. It has been found that the ASTM ash includes alumina, silica, mullite, and Ca compounds as crystalline phases, whereas the DTF ash includes spherical drops with K, Fe, and Ca condensed on the surface. In a DTF ash, only mullite existed as crystalline phase. 'Che deposits existed as glass phases which were formed by solidification from melts, and Fe was transformed to Fe^(3+) silicate and Si was concentrated on the lower part of the deposit. This fact indicates that, among various inorganic elements in coal, Si controls the fusion. Although it was initially predicted that Alaska coal ash have strong slagging propensity based on the results of ASTM ash characterization, the results of analysis of the DTF deposits shows that the deposits can be easily removed from the heat transfer area because it is enriched with Ca which reduces the strength of its adhesion to the solid surface.

烏貝散이 흰쥐 胃의 Gastrin, Histamine, Somatostatin 면역반응세포에 미치는 영향

이시섭,나현욱,고병문,이광규,이창현 대한동의병리학회 2001 동의생리병리학회지 Vol.15 No.5

To investigate the elects on the administration of Opae-san in rats. Opae-san (500mg/day) and omeprazole(10mg/day) were administration with stomach tube for 4 weeks and 8 weeks. This experiment were investigated numerical change of immunoreactive cells of gastric, histamine and somatostatin in rat stomach mucosa by the immunohistochemical method. The results were as follows : 1. In Opae-san administration group for 4 weeks, the number of gastric immunoreactive cells were increased in one and a half times than that of control group. In omeprazole administration group for 4 weeks, the number of gastric immunoreactive cells were increased in four times than that of control group. In Opae-san administration group for 8 weeks, the number of gastric immunoreactive cells were increased four times than that of control group. In omeprazole administration group for 8 weeks, the number of gastrin immunoreactive cells were increased in six times than that of control group. 2. In Opae-san administration group for 4 weeks, the number of histamine immunoreactive cells were increased in two times than that of control group. In omeprazole administration group for 4 weeks, the number of histamine immunoreactive cells were increased in six times than that of control group. In Opae-san administration group for 8 weeks, the number of histamine immunoreactive cells were increased three times than that of control group. In omeprazole administration group for 8 week, the number of histamine immunoreactive cells were increased in seven times than that of control group. These results suggest that Opae-san extracts inhibit the secretion of gastric acid and this extract use to therapeutic herb of gastric disorders related to the hyperacidity and gastric ulcer.

사연 및 동판저수지의 식물성 플랑크톤에 관한 연구

강현무,박시섭,이상명,조현아,이진우,이호원 慶南大學校 附設 基礎科學硏究所 1995 硏究論文集 Vol.7 No.-

본 연구는 1994년 2,5,8,11월의 4회에 걸쳐 실시하였다. 조사 결과 동정 분류된 식물성 프랑크톤은 사연호가 6강 126분류군, 동판저수지가 5강 100분류군으로 전체 6강 211분류군이 출현하였다. 월별 종조성은 사연호에서 5월이 50분류군, 8월이 43분류군, 2월이 31분류군 순으로 출현하였다. 동판저수지는 5월이 49분류군, 11월이 27분류군, 2월 25분류군, 8월이 24분류군 순이다. 강별 구성비에서 두 지역모두 녹조강이 가장 많고 다음이 규조강 순이다. 전체 종조성은 사연호는 녹조강 54.3%, 규조강이 25.2%, 유글레나강 7.9%, 남조강 7.1%, 황녹조강 4.7%, 황갈조강 0.8%순이다. 동판저수지의 전출현 종에 대한 종조성은 규조강 51.4%, 녹조강33.9%, 유글레나강 11.0%, 황갈조강 3.7%, 황녹조강 10.9%의 종조성을 나타내었다. 환경요인은 pH의 경우 사연호 8월에 9.28로 가장 높고, DO는 동판 5월이 12.3㎎/ℓ으로 가장 높게 나타났다. 클로로필 a는 사연 2월이 13.1㎎/㎥로 가장 높으며, 부유물질은 동판저수지 5월에 85.0㎎/ℓ으로 가장 높았다. Phytoplankton flora of Sayoun and Tongpan-Reservoirs were studied. A total of 204 taxa (Sayoun-Reservoir, 126 taxa : Tongpan-Reservoir, 100 taxa) were indentified. The Major taxa of two localities was Chlorophyceae 46.7% and Bacillariophyceae 35.1%. As the bloom causing species. Microcystis aeruginosa. Ceratium hirudinella and Peridinium divergens were identified. The chlorophyll a concentration of Tongpan-Reservoir was higher then Sayoun-Reservoir.

조혈모세포이식 환자에서 침습성 진균 감염에 대한 Micafungin의 예방 효과 및 안전성

김시현,이동건,최수미,권재철,박선희,최정현,유진홍,이성은,조병식,김유진,이석,김희제,민창기,조석구,김동욱,이종욱,민우성,박종원 대한감염학회 2010 감염과 화학요법 Vol.42 No.3

Background: Micafungin, a potent inhibitor of 1,3-β-D-glucan synthase, is a novel antifungal agent of the echinocandin class. In vitro study showed that micafungin was effective against Aspergillus species as well as Candida species, but clinical data on the prophylactic efficacy against invasive fungal infections (IFIs) other than candidiasis are still lacking. Materials and Methods: We identified 60 consecutive adult hematopoietic stem cell transplantation (HSCT) recipients who received at least 3 doses of micafungin during neutropenic period. Micafungin was started as an alternative in patients who were intolerant or had adverse events (AEs) to primary prophylactic antifungal agents. We retrospectively reviewed the medical records and analyzed the efficacy and safety of micafungin for prophylaxis against IFIs. Results: The patients either had autologous (n=9) or allogeneic (n=51: 1 syngeneic, 24 sibling, 26 unrelated donor) HSCT. Itraconazole oral solution (n=58) was the most frequently used first line antifungal agent for prophylaxis and was administered for median 11 days. The most frequent cause of switch to micafungin was vomiting (n=42). The duration of neutropenia and micafungin administration was median 13 and 12 days, respectively. A successful outcome was achieved in 45 (75%) patients. Empirical antifungal therapy was initiated in 13 (22%) patients. There were 2 cases (3.3%) of breakthrough fungal infections which comprised a probable invasive pulmonary aspergillosis and a possible invasive fungal sinusitis. There was no case of invasive candidiasis. A total of 53 (88%) patients experienced at least one AE regardless of causality during micafungin administration. The most frequent AEs were hypokalemia, vomiting, diarrhea, and elevated serum aspartate aminotransferase or alanine aminotransferase. Among the aforementioned AEs, only 1 case of diarrhea could be classified as a probable relation with micafungin when causality was assessed. There was no AEs that caused discontinuation of micafungin. Conclusions: Micafungin seems to be a safe and effective agent for prophylaxis of IFIs including aspergillosis as well as candidiasis in HSCT recipients. However, further large, prospective, and randomized comparative studies are warranted for aspergillosis.

조혈모세포이식 환자에서 발생한 Cytomegalovirus 질환의 특징 : 일개 대학변원에서 최근 10년간의 경험

최수미,이동건,박선희,김시현,김유진,민창기,김희제,이석,최정현,유진홍,김동욱,이종욱,민우성,신완식,김춘추 대한감염학회 2009 감염과 화학요법 Vol.41 No.1

Background : Studies on cytomegalovirus (CMV) diseases in Korean hematopoietic stem cell transplant (HSCT) recipients are lacking and do not reflect the recent trends of advances and changes. Therefore, we tried to analyze the clinical features of CMV diseases in HSCT recipients over the past 10 years at a tertiary university hospital in Korea. Methods : Retrospective review of medical records was done for all adult HSCT patients who received transplant at the Catholic HSCT Center from January 1998 to January 2008. Results : Forty-four cases (2.2%) of CMV diseases were identified. CMV pneumonia was diagnosed in 17 patients, retinitis in 16 patients, enterocolitis in 7 patients, esophagitis 1 patient, gastritis in 1 patient, duodenitis in 1 patient, and hepatitis in 1 patient. The median onset of symptom was 90 days after transplantation. Late CMV diseases accounted for 47.7%. CMV related death varied from 0 to 58.8% according to the involved organ. CMV retinitis was diagnosed relatively later in the course of transplantation mostly in patients who had chronic graft versus host disease (GVHD). On the contrary, CMV enterocolitis mainly occurred in patients who suffered from acute GVHD. The overall concurrent CMV reactivation was documented to be 63.6%: the concurrent CMV reactivation was observed only in 37.5% of patients with retinitis. Conclusions : We observed some differences in the pattern of CMV disease manifestation according to the involved organ and reconfirmed the fact that CMV pneumonia is the most common and fatal disease in HSCT recipients. Additionally, CMV retinitis was not uncommon in HSCT recipients. Since specific marker does not exist in predicting retinitis, regular ocular examination should be done thoroughly, especially in patients with chronic GVHD.

고품질 4H-SiC 단결정 성장을 위한 다공성 흑연 판의 역할

이희준,이희태,신희원,박미선,장연숙,이원재,여임규,은태희,김장열,전명철,이시현,김정곤,Lee, Hee-Jun,Lee, Hee-Tae,Shin, Hee-Won,Park, Mi-Seon,Jang, Yeon-Suk,Lee, Won-Jae,Yeo, Im-Gyu,Eun, Tai-Hee,Kim, Jang-Yul,Chun, Myoung-Chul,Lee, Si-Hyun 한국결정성장학회 2015 한국결정성장학회지 Vol.25 No.2

본 연구에서는 PVT법으로 4H-SiC 단결정 성장 시 다공성 흑연판을 사용하여 Si/C 비율이나 온도구배, 물질전달의 향상시킴으로써 고품질의 SiC 단결정 기판 제작을 목적으로 연구를 진행하였다. 연구에 사용된 SiC 소스 물질은 흑연 도가니에 넣어 흑연 단열재로 쌓인 구조로 실험을 하였다. 성장온도는 $2100{\sim}2300^{\circ}C$, 그리고 성장압력은 10~30 Torr의 압력으로 아르곤과 질소 분위기에서 성장시켰다. 종자정은 2인치의 $4^{\circ}$ off-axis 4H-SiC의 C면 (000-1)을 사용하였고 다공성 흑연판은 SiC 소스 물질 위에 삽입하였다. 4H-SiC 결정다형 안정화를 위한 C-rich 조건이나 균일한 온도구배를 만들어주기 위해 다공성 흑연판을 삽입하여 실험을 진행하였다. 일반적인 도가니의 경우, 성장된 wafer에서 6H-, 15R-SiC와 같은 다양한 결정다형이 관찰된 반면에 다공성 흑연판을 삽입한 도가니에서는 4H-SiC만 관찰되었다. 또한 다공성 흑연판을 삽입한 도가니에서 성장된 결정에서 MP나 EP의 낮은 결함밀도를 보였으며 결정성 또한 향상된 것을 학인하였다. The present research is focused on the effect of porous graphite what is influenced on the 4H-SiC crystal growth by PVT method. We expect that it produces more C-rich and a change of temperature gradient for polytype stability of 4H-SiC crystal as adding the porous graphite in the growth cell. The SiC seeds and high purity SiC source materials were placed on opposite side in a sealed graphite crucible which was surrounded by graphite insulator. The growth temperature was around $2100{\sim}2300^{\circ}C$ and the growth pressure was 10~30 Torr of an argon pressure with 5~15 % nitrogen. 2 inch $4^{\circ}$ off-axis 4H-SiC with C-face (000-1) was used as a seed material. The porous graphite plate was inserted on SiC powder source to produce a more C-rich for polytype stability of 4H-SiC crystal and uniform radial temperature gradient. While in case of the conventional crucible, various polytypes such as 6H-, 15R-SiC were observed on SiC wafers, only 4H-SiC polytype was observed on SiC wafers prepared in porous graphite inserted crucible. The defect level such as MP and EP density of SiC crystal grown in the conventional crucible was observed to be higher than that of porous graphite inserted crucible. The better crystal quality of SiC grown using porous graphite plate was also confirmed by rocking curve measurement and Raman spectra analysis.

GIS를 이용한 산불발생위험지역 구분

이시영,안상현,원명수,이명보,임태규,신영철 한국지리정보학회 2004 한국지리정보학회지 Vol.7 No.2

산불로 인한 재해를 미연에 방지하고 피해를 저감하기 위해서는 산불발생위험지역을 사전에 파악하여 예방대책을 세울 필요가 있다. 따라서 본 연구에서는 산불발생인자에 따른 산불발생위험지역을 구분하고자 겸상북도 의성군에서 발생한 산불피해지역에 대하여 임상, 지형 등에 대하여 조사하였다. 조사된 요인들 간 독립성 유무를 상관분석을 이용하여 산불발생과 관련 있는 7개의 주제도를 선정하였으며, 선정된 주제도를 조건부확률과 지리정보시스템을 이용하여 산불발생확률을 계산하였다. 계산된 산불발생확률을 20개 등급으로 지수화하여 산불발생위험지역을 구분하였다. In order to decrease the area damaged by forest fires and to prevent the occurrence of forest fires, we are making an effort to improve prevention measures for forest fires. The objective of this study is to classify hazard regions where forest fires occur based on the factors that contribute to the occurrence of forest fires. Forest fire sites in the Uiseong-gun, Gyeongsangbuk-do were surveyed according to the factors of forest type and topographic characteristics where the forest fires occurred. We used a correlation analysis to determine the forest fire occurrence factors and a conditional probability analysis and GIS to determine a forest fire danger index. The resulting forest fire danger index was used in the classification of forest fire occurrence risk regions.