Electrical Characteristics of AlxGa1-xN/GaN Heterostructure withIsoelectronic Al-Doped Channel for HFET Application

이정희,Jae-Hee Park,Jae-Hoon Lee,Jae-Seung Lee,Jong-Wook Kim,Kye-Seok Lee,Sung-Bum Bae,Sung-Ho Hahm 한국물리학회 2003 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.42 No.III

Based on investigating the effects of isoelectronic Al-doping on GaN film, a new layer structure is proposed for a heterostructure field effect transistor (HFET) including an isoelectronic Al-doped channel. The electron mobility measured at 77 (300) K significantly increased from 145 (130) cm$^2$/V$\cdot$s in the undoped sample to 823 (440) cm$^2$/V$\cdot$s in the Al-doped sample grown with a trimethylaluminum flow rate of 3 $\mu$mol /min, while maintaining the background doping concentration below $\sim$ 6 $\times$ 10$^{16}$ cm$^{-3}$. Two-dimensional electron gas mobilities of 1690 and 9280 cm$^2$/Vs were measured for a 25-nm Al$_{0.3}$Ga$_{0.7}$N/1-nm AlN/70-nm Al-doped channel/GaN heterostucture at 300 and 77 K, respectively. The improved results are explained based on a decrease in the compensating acceptors or other defects associated with the formation of screw dislocation due to the incorporation of Al in the channel layer, plus a decrease in the alloy disorder scattering in the heterostructure based on introducing a binary thin AlN layer between the Al$_{0.3}$Ga$_{0.7}$N and Al-doped channel layers.

세계화와 상호공존의 시민정신: 하퍼 리의 『앵무새 죽이기』

이정희 ( Chung Hee Lee ) 한국현대영미소설학회 2004 현대영미소설 Vol.11 No.1

In-situ 성장법에 의한 ZIF-8 분리막 합성 및 H₂/CO₂ 분리 특성

이정희,유성종,김진수,Lee, Jeong Hee,Yoo, Sung Jong,Kim, Jinsoo 한국막학회 2018 멤브레인 Vol.28 No.2

ZIFs (Zeolitic imdazolate frameworks)은 높은 화학적 열적 안정성, 높은 비표면적과 조절 가능한 기공구조로 최근 분리막 소재로 큰 관심을 받고 있다. 본 연구에서는 두 가지 종류의 다공성 지지체(${\alpha}$-alumina 및 YSZ)를 사용하여 in situ 성장법으로 ZIF-8 분리막을 합성하고, $H_2/CO_2$ 기체 투과 특성을 조사하였다. 결함 없는 ZIF-8층을 합성하는데 있어, 기공이 작은 YSZ 지지체는 ${\alpha}$-alumina 지지체 보다 더 적은 시간이 요구되었다. 합성시간이 3 h인 경우, ${\alpha}$-alumina 및 YSZ 지지체위에 형성된 ZIF-8 분리막은 약 10 정도의 $H_2/CO_2$ 선택도를 보였다. ZIFs (Zeolitic imdazolate frameworks) have attracted great attention as membrane materials in recent years due to their high chemical and thermal stability, high specific surface area and adjustable pore structure. In this study, ZIF-8 membranes were synthesized by in-situ growth method on two different support materials (${\alpha}$-alumina and YSZ) and their $H_2/CO_2$ gas permeation characteristics were investigated. In order to synthesize defect-free ZIF-8 layer, YSZ support required less synthesis time than ${\alpha}$-alumina support due to smaller pore size. After in-situ growth for 3 h, ZIF-8 membranes prepared on both YSZ and ${\alpha}$-alumina supports showed $H_2/CO_2$ selectivity of about 10.

표준화 포럼 탐방 - 실감형혼합현실기술포럼

이정희,Lee, Jeong-Hui 한국정보통신기술협회 2017 TTA저널 Vol.2017 No.-

학교도서관과 독서지도의 문제

이정희,Lee, Jeong-Hui 한국도서관협회 1976 圖協月報 Vol.17 No.7

백서의 아킬레스 건 봉합 후 Hyaluronate-Carboxymethyl cellulose가 조직 유착에 미치는 영향

이정희,정비오,김교영,Lee, Jung-Hee,Jeong, Bi-O,Kim, Gou-Young 대한족부족관절학회 2009 대한족부족관절학회지 Vol.13 No.1

Purpose: The purpose of this study was to evaluate the effect of Sodium hyaluronate-Sodium carboxymethyl cellulose (HA-CMC) on tissue adhesion after tenorrhapy in tenotomized Achilles tendon of the Sprague-Dawley rat. Materials and Methods: Twenty-eight legs of 14 Sprague-Dawley rat were used in study. After tenotomy of the Achilles tendons, tenorrhaphies were performed. Simple tenorrhaphy without any other procedures were performed on the left Achilles tendons (control group), and additional HA-CMC injections were done prior to the tenorrhaphy on the right Achilles tendons (HA-CMC group). Gross and histological examinations were made to identify differences between the two groups, 1, 2, 6, 8, 10, 12 and 14 weeks respectively. Results: Distinct decrease in granulation tissues and adhesions were seen in the HA-CMC group during gross inspection at 6 and 8 week after the operation. On histological analysis of the HA-CMC group, although increased infiltrations of inflammation cells were observed during 1 week, less adhesion were seen at 6, 8 and 10 weeks after the operation. In HA-CMC group, superior healing processes were seen at 6, 8 and 10 weeks and less fibrotic changes, compared to control group, were seen at 2 and 6 weeks. Conclusion: Prevention of adjacent tissue adhesion was made possible through decrease in collagen deposition and fibrosis by injecting HA-CMC before tenorrhaphy of Achilles tendon. Also, histologically faster healing process of the collagen fibers within the Achilles tendon was observed.

학교도서관발전을 위한 도서관정책

이정희,Lee, Jeong-Hui 한국도서관협회 1975 圖協月報 Vol.16 No.10

학교도서관의 회고와 전망

이정희,Lee, Jeong-Hui 한국도서관협회 1973 圖協月報 Vol.14 No.12

흰쥐에서 DWP-04가 D-galactosamine에 의해 유도된 간독성의 보호효과

이정희,지상철,김석환,신영호,최종원,Lee Jung-Hee,Chi Sang Cheol,Kim Seok-Hwan,Shin Young-Ho,Choi Jongwon 한국생명과학회 2005 생명과학회지 Vol.15 No.3

This study was conducted to investigate the biological activity and hepatoprotective effect of DWP-04 [DDB : selenium yeast: glutathione (31.1 : 6.8 : 62.1(w/w/w)] in D-galactosamine (GaIN) intoxicated rats. The DWP-04 (50, 100 or 200 mg/kg) or its vehicle was orally administered everyday before the start of GaIN injection (400 mg/kg, ip) for two weeks and animal decapitated for 24 hrs after GaIN­injected. The activities of serum enzymes, markers of liver function, were increased in the GaIN group compared to normal group and significantly lowered in the DWP-04 pretreated group than in the GaIN group. Hepatic lipid peroxide level and activities of phase 1 enzymes were significantly higher than those of GaIN group compared to normal group and lower in the DWP-04 pretreated group than in the GaIN group, and phase II enzyme activities in liver were lower in the GaIN group than in the normal group and were increased in the DWP-04 pretreated group than in the GaIN group. Total hepatic glutathione content and glutathione biosynthesis enzymes were lower in the GaIN group than in the normal group and were increased in the DWP-04 pretreated group than in the GaIN group. Therefore, the current results indicated that DWP-04 administration alleviated the GaIN-induced adverse effect through enhancing the antioxidant enzyme activities. 간기능 보호 작용이 있는 것으로 알려진 DDB, selenium과 glutathione의 혼합제제인 DWP-04의 간보호 작용을 검토할 목적으로 DWP-04를 실험동물에 경구로 투여하고서 D-galactosamine으로 간독성을 유발하여 혈액의 변동 및 간 조직에서의 활성산소 생성계 및 해독계의 활성에 미치는 영향을 관찰한 결과 GaIN의 단독투여는 대조군에 비하여 혈중 간 기능 지표효소 및 간 조직에서의 지질과산화의 함량이 현저히 증가하였으나, DWP-04의 전처리로 현저히 감소되었다. CaIN의 단독 투여로 활성산소의 생성계인 phase 1계의 효소가 현저히 증가하던 것이 DWP-04의 처리로 억제되었으며 해독계인 phase II계의 효소는 GaIN의 투여로 대조군에 비하여 억제되던 것이 DWP-04의 전처리로 정상군에는 미치지 않으나 유의성 있게 증가되었다. 간 조직중 glutathine의 함량은 CaIN의 투여로 현저히 억제되었으며 DWP-04의 투여로 증가하였는데 이러한 결과는 DWP-04의 투여로 glutathione peroxidase의 활성보다는 $\gamma-glutamylcysteine$ synthetase의 활성을 조절한 결과로 생각된다. 이상의 결과를 종합하여 볼 때 DWP-04의 투여는 활성산소의 생성 및 해독계를 조절하므로서 GaIN으로 인한 간손상을 보호하는 효과가 있는 것으로 사료된다.

펩타이드 함유 화장품의 속눈썹 상태변화 연구

이정희,Lee, Jung-Hee 중소기업융합학회 2020 융합정보논문지 Vol.10 No.11

본 연구는 펩타이드 함유 화장품이 속눈썹 미용법으로서의 효능을 검증해 보고자 하였다. 연구대상은 20세 여성 21명을 대상으로 실험군(오른쪽 속눈썹)과 대조군(왼쪽 속눈썹)으로 설정하여 4주간 펩타이드 화장품의 사용에 따른 변화 측정을 진행하였다. 분석결과, 속눈썹의 길이와 밀도 변화는 집단과 실험기간 간의 상호작용, 각 실험기간에 따른 주 효과에서 유의한 차이가 있는 것으로 나타났다(p<.001). 속눈썹의 밀도와 두께 변화에서는 측정 시기별 집단 간 차이에서 3주차와 4주차에서 유의미한 차이가 있는 것으로 나타났다(p>.05, p>.01). 펩타이드를 함유한 화장품은 미용적 시술에 의한 부작용을 고민하는 사람들에게 속눈썹의 길이와 수적인 증가로 안전하고 아름다운 속눈썹을 위한 효과적인 미용방법임을 효과적으로 입증하였다. 이에 향 후 다양한 연령층으로 확대된 연구의 진행을 기대한다. The purpose of this study was to verify the efficacy of cosmetics containing peptides as a cosmetic method for eyelashes. The study subjects were 21 women aged 20 years, set as the experimental group (right eyelash) and the control group (left eyelash), and measured changes according to the use of peptide cosmetics for 4 weeks. As a result of the analysis, the change in the length and density of eyelashes showed significant differences in the interaction between the group and the experiment period, and in the main effect according to each experiment period (p<.001). In the change of eyelash density and thickness, it was found that there was a significant difference at week 3 and week 4 in the difference between groups by measurement period (p>.05, p>.01). Cosmetics containing peptides have been effectively proven to be an effective cosmetic method for safe and beautiful eyelashes by increasing the length and number of eyelashes to those who suffer from side effects caused by cosmetic procedures. In the future, we look forward to expanding research to a wide range of age groups.