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金泰根 慶北大學校 經營大學院 1993 最高經營者課程 論文集 Vol.- No.18

Reduction of Buffer Leakage in AlGaN/GaN HEMTs with an AlGaN Current-Blocking Barrier by using a Two-Dimensional Simulation

김태근,김수진,김동호,김재무,최홍구,한철구 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5

We report improved transport characteristics for of AlGaN/GaN/AlGaN double heterostructure (DH) high-electron-mobility transistors (HEMTs) with an AlGaN current-blocking-barrier (CBB) structure. The proposed device features a 40-nm-thick AlGaN CBB embedded into a conventional AlGaN/GaN HEMT to prevent the two-dimensional electron gas (2-DEG) of the HEMT from spilling over the buer layer, effectively reducing the buffer leakage current. Simulation results clearly indicate that the proposed AlGaN/GaN/AlGaN DH-HEMT has not only better current confinement of the 2-DEG channel but also less leakage currents into the GaN buffer layer compared with the conventional AlGaN/GaN HEMT. In the DH-HEMT with an AlGaN CBB, we observed an approximately 56.9 % improvement in the maximum drain current density (ID;max) and a 16 % improvement in maximum transconductance (gm;max) at zero gate bias condition over the conventional SH-HEMT. We report improved transport characteristics for of AlGaN/GaN/AlGaN double heterostructure (DH) high-electron-mobility transistors (HEMTs) with an AlGaN current-blocking-barrier (CBB) structure. The proposed device features a 40-nm-thick AlGaN CBB embedded into a conventional AlGaN/GaN HEMT to prevent the two-dimensional electron gas (2-DEG) of the HEMT from spilling over the buer layer, effectively reducing the buffer leakage current. Simulation results clearly indicate that the proposed AlGaN/GaN/AlGaN DH-HEMT has not only better current confinement of the 2-DEG channel but also less leakage currents into the GaN buffer layer compared with the conventional AlGaN/GaN HEMT. In the DH-HEMT with an AlGaN CBB, we observed an approximately 56.9 % improvement in the maximum drain current density (ID;max) and a 16 % improvement in maximum transconductance (gm;max) at zero gate bias condition over the conventional SH-HEMT.

Investigation of Simulated and Measured Program Characteristics in 4-bit/cell Charge-trap Flash (CTF) Memories

김태근,김재무,Yu Jeong Seo,Ho-Myoung An,Sung Wook Park,김대환 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.1

We investigate the simulated and measured program characteristics for 4-bit program operations in silicon-oxide-nitride-oxide-silicon (SONOS) devices by using two-dimensional (2-D) device simulations. For this calculation, the width of the region with charge trapped locally in the drain region is assumed to be as narrow as 44 nm to remove second-bit effects during the 2-bit and 4-bit operation. We determine the reverse read voltage for screening bit-1 to be 2.5 V and confirm that both 2-bit and 4-bit characteristics are successfully observed in our devices. From the threshold voltage shift, the densities of trapped charge are estimated to be 0 × 1019, 3 × 1019, 6 × 1019 and 9 × 1019 cm−3 at 4-level states, respectively. We also find that these simulation results are reasonably consistent with the experimental results achieved in this work.

Correlation Between p53 and p21 Proteins Expression and Prognostic Factors Related with Colon Cancer

김태근,김태전 대한임상검사과학회 2007 대한임상검사과학회지(KJCLS) Vol.39 No.2

This study was designed to investigate the correlation between the expression rate of p53 and p21 proteins by immunohistochemical staining and tumor prognostic factors including the tumor size, histological differentiation and Dukes' stage of tumor prognostic factors in colon cancer, and to acquire necessary data for the presumption of diagnosis, treatment and prognosis of colon cancer patients. From January 2000 to January 2003 at Hanyang University Guri Hospital, the paraffin blocks of 35 patients diagnosed with colon cancer whose pathologic reports were possible to review were selected. Harris hematoxylin & eosin (H&E) staining and immunohistochemical staining by ABC (Avidin Biotin Conjugate) method were performed. The histological differentiation grade and stage were classified according to the classification of the World Health Organization (WHO) and modified Dukes's stage from H&E staining. The expression rate of p53 and p21 proteins were analyzed by immunohistochemical staining. The results was analyzed statistically by SPSS (Windows version 8.0). As a result, the expression rate of p53 protein was 11.4% (4 cases) in clear differentiation, 48.6% (17 cases) in moderate differentiation, and 17.1% (6 cases) in poor differentiation. In other words, the poorer the differentiation, the higher the expression rate of p53 protein (p<0.05). The expression rate of p21 was 17.1% (6 cases) in clear differentiation, 40.0%(14 cases) in moderate differentiation, and 8.6% (3 cases) in poor differentiation, According to the progression of histological malignant degeneration, the expression rate of p21 protein decreased distinctively (p<0.05). However, the correlation between the two above mentioned proteins and the tumor-size and Dukes' stage was not of statistical significance. In the comparison of the expression rate of p53 protein with that of p21 protein, in 10 cases, p53 protein expression was positive while p21 protein expression was negative, and in 6 cases, p53 protein expression was negative whereas p21 protein expression was positive. Consequently a statistically significant inverse correlation between the expression rate of p53 protein and that of p21 protein was observed (p<0.05). In conclusion, we found a significant correlation between histological differentiation and the expression rate of p53 and p21 proteins (p<0.05), and a significant inverse correlation between the expression rate of p53 protein and that of p21 protein (p<0.05). Also, it could be confirmed that the over expression of p53 and p21 proteins is closely associated with the occurrence of colon cancer and its progress. Therefore, it is thought that this study may be greatly beneficial to the presumption of diagnosis, treatment and prognosis of colon cancer patients. .

Streptococcus mutans의 치태형성에 대한 Leuconostoc lactis 51의 영향

김태근,양규호,오정석 전남대학교 치과대학 2000 전남치대논문집 Vol.12 No.1

Dental caries is a bacterial disease of the dental hard tisssus, characterized by a localized, progressive, molecular disintegration of tooth structure. The action of Leuconostoc lactis 51 about plaque formation and replication by Streptococcus mutans was studied as follows. 1. Lower amount of plaque was produced at the mixed culture of S. mutans and L. lactis 51 than S. mutans alone on the wires in the beaker. 2. Fewer cells of S. mutans were replicated at the mixed culture of S. mutans and L. lactis 51 than S. mutans alone. 3. In M17Y broth, viable cells of S. mutans and L. lactis 51 increased for 12 hours, and decreased for 24 hours. In M17YS broth, viable cells of S. mutans showed time-dependent decrease at mixed culture of S. mutans and L. lactis 51. 4. The culture supernatant of L. lactis 51 didn't inhibit the replication of S. mutans and the formation of artificial plaque. 5. Sucrose and frutose were extracted from the culture supernatant of L. lactis 51 in M17YS broth. These results suggest that L. lactis 51 isolated from the oral cavity inhibits the replication of S. mutans and the formation of artificial plaque.

뇌손상 환자의 기능적 뇌자기공명영상(fMRI)와 Diffusion tensor tractography(DTI)을 이용한 운동신경로의 연구

김태근,김창희,김태욱,신진욱,권태한 대한자기공명기술학회 2005 대한자기공명기술학회지 Vol.15 No.-

척추골수의 확산강조영상 척추종판에 인접한 골수를 침윤하는 퇴행성 척추와 척추염의 감별

김태근,김창희,송영찬,양성렬,권태한,변우목,장용민 대한자기공명기술학회 2002 대한자기공명기술학회지 Vol.12 No.-

구연발표 : 전립선종양에 대한 면역조직화학적염색의 유용성

김태근,노정환,유숙 대한임상병리사협회 2008 조직세포검사학회 발표자료집 Vol.2008 No.-

배경: 전립선암은 현재 국내의 55세 이후 남성에서 3.2%정도로 발병율이 높다. 그렇지만 생존율 또한 높은 질병으로 조기진단이 중요하다. 현재 전립선종양을 초기에 진단하는 방법으로 침생검이 시행되고 있다. 따라서 본 연구는 환자의 전립선 침생검 검체에서 조직의 악성도를 구분하기위한 방법으로 K-903, CK5, p63의 발현이 유의한 것인지 알아보고자 하였다. 방법: 한양대학교 구리병원에서 2008년 1월부터 2008년 6월까지 시행한 침생검 검체 72예를 대상으로 전립선종양과 면역조직화학적염색 (K-903, CK-5, p63)의 발현양상을 비교분석하였다. 결과: 병리진단 72예 중 41예는 양성종양으로, 5예는 ASAP (atypical small acinar proliferation)로, 2예는 PIN (prostatic intraductal neoplasia)으로, 그리고 23예는 전립선암 (adenocarcinoma)으로 진단되었다. 고찰: 기저세포의 존재는 전립선종양의 악성도를 구분하는데 있어서 중요하다. 본 연구에서 종양의 악성도를 구분하기위한 방법으로 면역염색을 이용하였으며 그 유용성이 인정된다고 판단된다. 하지만 전립선종양과 면역염색 발현양상을 비교함에 있어서 그 병리검체가 충분하지는 않았으며, 차후 더 많은 검체를 확보하여 연구해야 할 것이다.

세침흡인생검 (Fine Needle Aspiration Biopsy Cytology)에서 Cyst fluid 와 관계된 타액선종양 (Salivary gland tumor)의 감별진단

김태근,김종열 대한임상병리사협회 2007 조직세포검사학회 발표자료집 Vol.2007 No.-

배경: 타액선 종양은 대부분이 분비선에서 기원하지만 두경부 종양 중에서도 병리 조직학적 양상이 매우 다양하며 FNABC를 이용한 세포학적인 진단은 더욱 어렵다. 이에 본 연구는 세포 도말 표본에서 Cyst fluid를 배경으로 나타날 수 있는 타액선 종양들을 검색하고 세포학적으로 비교분석 하였다. 방법: Cyst fluid를 배경으로 나타나는 타액선 종양은 Warthin``s tumor, Low-grade mucoepidermoid carcinoma, Acinic cell tumor, 그리고 Metastatic sqaumous cell carcinoma 등이 있으며 이들 종양에 대해 세포학적 특징을 비교분석 함으로서 감별진단이 가능한 특징들을 검색하였다. 결과: Warthin``s tumor는 판상, 집단상, 또는 단일의 배열을 가지는 호산성의 세포가 다량 관찰된다. 배경은 림프구와 점액성 물질 그리고 세포 파편들이 보이며, 때때로 편평상피와 술잔세포들이 관찰된다. 감별해야 될 진단으로는 squamous cell carcinoma와 low-grade mucoepidermoid carcinoma 등으로 Warthin``s tumor는 다수의 림프구가 관찰되며 편평상피화생은 거의 관찰되지 않는다. Low-grade mucoepidermoid carcinoma는 배경에 풍부한 점액이 보이지만, 세포의 수는 일반적으로 적다. 점액을 분비하는 세포들은 풍부한 공포의 세포질을 갖으며, 중간세포의 성긴 집단은 투명한 점액을 가진다. 편평상피세포는 거의 관찰되지 않으며 관찰된 편평상피세포는 세포질에 공포와 점액을 가진다. 감별해야 될 진단으로는 metastatic squamous cell carcinoma로 low-grade mucoepidermoid carcinoma는 점액세포가 관찰되며, 임상정보 또한 중요하다. Acinic cell tumor는 판상 또는 집단상의 호염성 세포들 풍부하다. 세포의 크기는 다양하고 핵은 편재되어 있으며 염색질은 bland 하게 보인다. 또한 세포질은 과립상 또는 청명하게 관찰된다. 나핵의 형태로 존재하는 종양세포의 대부분에서 작은핵인들이 관찰된다. 감별해야 될 진단으로는 low-grade mucoepidermoid carcinoma로 acinic cell carcinoma는 배경에 림프구가 관찰된다. metastatic squamous cell carcinoma는 평편상피에서 기원하는 종양으로 대부분이 상피세포로 구성되어 있으며 cyst fluid한 배경을 동반한다.

대학주도 방과후학교 사회적기업의 지속가능성 연구

김태근 국제개발연구소 2014 사회적기업과 정책연구 Vol.3 No.2

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