손상 없이 영구 접착 보철물을 제거할 수 있는 cementation type 임플랜트 지대주 개발에 관한 연구

최진호,이재봉,Choi Jin-Ho,Lee Jai-Bong 대한치과보철학회 2004 대한치과보철학회지 Vol.42 No.5

Purpose: This study was peformed to investigate the retrievability of the cemented crown from the cementation type implant abutment. Material and method: The cementation type implant abutments (NEOBIOTECH implant abutment regular, 3 degree taper, 10mm length, 4mm diameter, Ti grade III, machined surface. Hwasung, Kyunggi-do) and cemented crowns were divided into 3 groups, depending on their hole angles formed in the crowns for their retrievability. The abutments and crowns were luted with 4 kinds of cements and separation test using metal wedge was executed with Instron 4465 Universal Testing Machine and the maximum impact force of the modified crown ejector was measured. Results and conclusion : 1. All of the cementation type implant abutments and cemented crowns were separated with relatively small force by metal wedge. 2. The retrieving force was minimum when the metal wedge was applied perpendicular to the axis of abutment. 3. The force for retrieving crowns from abutments was maximum in resin cement group, and reduced in orders of zinc phosphate cement, glass ionomer cement and zinc oxide eugenol cement. 4. The maximum force obtained by the crown ejector was higher than the retrieval force in ZOE and GI cement and lower than that in ZPC and resin cement. 5. If it has similar conditions clinically, the cemented crowns luted with 2 types of cements (ZOE, GI cement) can be safely retrieved from the cementation type implant abutments by the modified crown ejector.

치매동물모델 SAMP8에 있어서 기억. 학습장해에 미치는 알로에의 영향 III. SAMP8의 신경전달물질 및 그 대사산물에 미치는 알로에의 투여효과

최진호,김동우,김재일,한상섭,심창섭,Choi, Jin-Ho,Kim, Dong-Woo,Kim, Jae-il,Han, Sang-Seop,Shim, Chang-Sub 한국생명과학회 1996 생명과학회지 Vol.6 No.2

Aloe(Aloe arborescens M$_{ILL}$) has been used as a home medicine for the past several thousand in the world, and has been studied on anti-bacterial and anti-fungal activities, hypotension, atherosclerosis, myocardiac infartion, apoplexy, diabetes as a chronic digenerative disease, tumors, gastrointestinal tract, liver and pancreas' diseases, and genitourinary tract etc. SAMP8 as a learing and memory impairment animal model were fed basic and/or experimental diets with 1.0% freezing dried(FD)-aloe for 8 months. The passive avoidance tests such as acqusition trial and retention test were significantly higher in aloe group than in control group. Grading score of senescence resulted in a marked decreases in aloe group compared with control group. Acetylcholinesterase(AChE) activity was remarkably increased in aloe group compared with control group. Neurotransmitters such as dopamine(DA) and serotonin(5-HT) almost did not change by the feeding of aloe-added diet, but their metabolites such as homovanillic acid(HVA) and 5-hydroxy-indole acetic acid(5-HIAA) in aloe group were significantly increased compared with control group. Therefore, the ratios of HVA/DA and 5-HIAA/5-HT as a ratio of metabolite on neurotransmitter were significantly increased by the feeding of aloe-added diet. These results suggest that aloe vara may be activated acetylcholinesterase, the metabolite of neurotransmitter, and ratios of metabolite on neurotransmitter, resulting ina greater prevention of learning and memory impairments such as Alzheimertype dementia.

해양오염의 진단을 위한 생화학적 오염지표에 관한 연구 VI. 황해산 도다리 (Pleuronichthys cornutus)의 콜린에스테라아제 활성의 변화

최진호,김동우,박청길,양동범,CHOI Jin-Ho,KIM Dong-Woo,PARK Chung-Kil,YANG Dong Beom 한국수산과학회 1997 한국수산과학회지 Vol.30 No.4

해양오염의 진단을 위한 생화학적 오염지표 설정의 기초연구의 일환으로서 오염의 정도가 심각한 서해산 도다리 (Pleuronichthys cornutus)의 뇌 및 근육중의 acetylcholinesterase (AChE) 및 butyrylcholinesterase (BChE)의 활성, 그리고 lactate dehydrogenase(LDH)의 활성을 분석 평가하였다. 서해안 자연산 도다리의 뇌 및 근육중의 AChE의 활성은 $7,708.2{\pm}549.7\~8,872.7{\pm}515.1\;unit/min/mg$ protein (brain) 및 $4,071.2{\pm}647.9\~6,0245{\pm}493.7unit/min/mg$ protein (muscle)로서 대조군으로 사용한 동해안 포항의 자연산 도다리의 뇌 및 근육중의 AChE의 활성 ($11,168.9{\pm}822\;unit/min/mg\;protein\;(brain)$ 및 $6,812.2{\pm}533.0\;unit/min/mg\;protein\;(muscle);\;100\%$) 대비 각각 $69.1\~79.4\%$ 및 $59.8\~88.4\%$로서 대조군 대비 $20\~30\%$ (뇌) 및 $10\~40\%$ (근육) 정도나 유의적으로 저하되었다. 또한 서해안 자연산 도다리의 뇌 및 근육중의 BChE의 활성은 $274.1{\pm}51.2\~362.1{\pm}27.3\;unit/min/mg\;protein(brain)$ 및 $1,535.4{\pm}301.4\~1,854.7{\pm}250.7\;unit/min/mg\;protein(muscle)$로서 대조군으로 사용한 동해안 포항의 자연산 도다리의 뇌 및 근육중의 BChE의 활성 ($390.2{\pm}32.5\;unit/min/mg\;protein\;(brain)$ 및 $2,732.5{\pm}320.1\;unit/min/mg\;protein\;(muscle);\;100\%$) 대비 $92.8\~70.3\%$ (뇌) 및 $56.2\~67.9\%$ (근육)으로서, 대조군 대비 $10\~30\%$ 및 $35\~45\%$나 유의적으로 저하되었다. 서해안의 자연산 도다리의 혈청중의 LDH의 활성은 격포산 도다리를 제외하고 $0.075{\pm}0.030\~0.078{\pm}0.030\;unit/m\ell\;serum$로서 대조군으로 사용한 동해안 포항의 자연산 도다리의 혈액중의 LDH의 활성 $(0.105{\pm}0.030\;unit/m\ell\;serum;\;100\%)$ 대비 약 $30\%$정도나 유의적으로 저하하였다. 이상의 실험결과에서 볼 때 서해안의 자연산 도다리의 서식환경인 서해안의 오염도 상당히 심각할 것으로 판단된다. This study was designed to investigate the biochemical pollutant markers for diagnosis of marine pollutions by changes in cholinesterase activity of the flounder (Pleuronichthys cornutus) in the Yellow Sea of Korea. Acetylchotinesterase (AChE) activities in brain and muscle of wild flounders in the Yellow Sea were significantly lower $(20\~30\%\;and\;10\~40\%,\;respectively)$ than those of wild flounder in Pohang (control) of the last Sea. Butyrylcholinesterase (BChE) activities in brain and muscle of wild flounders in the Yellow Sea were significantly lower $(10\~30\%\;and\;35\~45\%,\;respectively)$ than those of wild flounder in Pohang of the East Sea. lactate dehydrogenase (LDH) activities in serum of wild flounders in the yellow Sea were significantly $(about\;30\%)$ lower than those of wild flounder in Pohang of the East Sea. These results suggest that AChE and BChE activities in brain and muscle of wild flounders of the Yellow Sea may be used as the most effective mean in a biochemical marker for diagnosis of pollutant effects by organophosphorus pesticides.

동작온도에 무관한 Frequency-to-Voltage 변환 회로

최진호,유영중,Choi, Jin-Ho,Yu, Young-Jung 한국정보통신학회 2007 한국정보통신학회논문지 Vol.11 No.5

본 논문에서는 CMOS 공정을 이용하여 동작온도에 무관한 FVC(Frequency-to-Voltage Convener) 회로를 제안한다. FVC는 FLL(Frequency Locked Loop)의 핵심 회로로서 주파수 신호를 전압신호로 변환하는 회로이다. FLL 회로는 PLL(Phase-Locked Loop) 회로 같이 고정된 주파수 신호를 생성하는 회로지만, PLL과는 달리 위상비교기, charge pump, 저역 필터 등이 필요치 않아 간단히 회로를 구성할 수 있다. FVC 회로의 설계는 $0.25{\mu}m$ CMOS 공정을 이용하였다. 설계되어진 회로의 입력 주파수는 70MHz에서 140MHz를 사용하였다. 회로의 시뮬레이션 결과 동작 온도가 $0^{\circ}C$에서 $75^{\circ}C$까지 변화할 때 변환된 출력 전압의 변화는 상온에 비하여 ${\pm}2%$이내였다. In this work, temperature stable frequency-to-voltage converter is proposed. In FVC circuit input frequency is converted into output voltage signal. A FLL is similar to PLL in the way that it generates an output signal which tracks an input reference signal. A PLL is built on a phase detector, a charge pump, and a low pass filter. However, FLL does not require the use of the phase detector, the charge pump and low pass filter. The FVC is designed by using $0.25{\mu}m$ CMOS process technology. From simulation results, the variation of output voltage is less than ${\pm}2%$ in the temperature range $0^{\circ}C\;to\;75^{\circ}C$ when the input frequency is from 70MHz to 140MHz.

Ni계 Deloro 50합금의 고하중 Sliding 마모거동에 미치는 마모환경의 영향

최진호,최세종,김준기,김용덕,김학수,문주현,백하충,이덕현,김선진,Choi, Jin-Ho,Choi, Se-Jong,Kim, Jun-Gi,Kim, Yong-Deog,Kim, Hak-Soo,Mun, Ju-Hyun,Baek, Ha-Chung,Lee, Duck-Hyun,Kim, Seon-Jin 한국재료학회 1998 한국재료학회지 Vol.8 No.12

Ni계 경면합금인 Deloro 50의 마모거동을 15ksi와 30ksi 접촉응력하의 여러 마모조건에서 조사하였다. 상온대기중에서 Deloro 50는 15ksi 응력에서도 극심한 응착마모가 발생하는 매우 낮은 마모저항성을 보였는데 이는 fcc 결정구조를 갖는 Deloro 50 기지상의 경도와 가공경화율이 strain-induced 상변태를 이웅한 hcp 결정구조의 Stellite 6보다 낮기 때문으로 생각된다. 상온 수중에서 Deloro 50는 15ksi 응력에서 Stellite 6와 비슷한 마모저항성을 보였는데 이는 물이 미세요철간의 금속간 접촉을 억제하였기 때문으로 생각된다. 그러나, 30ksi의 높은 접촉응력에서는 상온 대기중길 같은 응착마모가 발생하는 것으로 보아, 30ksi의 높은 응력에서는 물의 응착마모 억제 효과가 없었기 때문으로 생각된다. $300^{\circ}C$ 대기중에서 Deloro 50는 30ksi의 높은 접촉응력에서도 Stellite 6보다 우수한 마모저항성을 보였는데 이는 고온에서 마모시 생성되는 복합산화물층이 효과적으로 금속간 접촉을 방해하여 응착마모를 억제하였기 때문으로 생각된다. The sliding wear behavior of Ni-base hardfacing alloy, Deloro 50, was investigated at the contact stresses of 15ksi and 30ksi under the various wear environments. In air at room temperature, Deloro 50 showed lower wear resistance than Stellite 6 even at 15ksi due to the occurrence of severe adhesive wear. This seems to be caused by the lower hardness and work- hardening rate of Deloro 50 than those of Stellite 6. In water at room temperature, Deloro 50 showed as good wear resistance as Stellite 6 at 15ksi. It was considered to be due to that water could effectively prevent metal to metal contact through contacting asperities. However, Deloro 50 showed severe adhesive wear at 30ksi in water at room temperature. It seems to be that the water could not suppress adhesion wear at 30ksi. At $300^{\circ}C$ in air, Deloro 50 exhibited higher wear resistance than Stellite 6 even at 30ksi. It was considered that the oxide glaze layers formed on wear surface during sliding, effectively prevented direct metal-to-metal contacts.

텅스텐 할로겐 램프를 사용하는 ZMR공정의 매개변수 최적화에 관한 연구

최진호,송호준,이호준,김충기,Choi, Jin-Ho,Song, Ho-Jun,Lee, Ho-Jun,Kim, Choong-Ki 한국재료학회 1992 한국재료학회지 Vol.2 No.3

ZMR공정에서 발생하기 쉬운 폴리실리콘의 엉김현상(agglomeration), 슬림, 그리고 실리콘기판이 국부적으로 녹는 현상 등을 방지하기 위한 방법과 재결정화된 박막의 질을 향상시키기 위하여 폴리실리콘과 보호 산화막(capping oxide)두계를 변화시킨 실험 결과를 서술한다. 폴리실리콘의 엉김현상은 폴리실리콘과 보호 산화막 그리고 폴리실리콘과 매몰 산화막(buried oxide)의 계면에서의 wetting각과 관계되는데, 엉김현상을 방지하기 위해서는 암모니아 가스 분위기에서 $1100^{\circ}$C, 3시간 동안 열처리하여 폴리실리콘과 보호 산화막 그리고 폴리실리콘과 매몰 산화막의 계면에 질소를 주입시키면 된다. 실리콘 기판의 뒷면이 국부적으로 녹아 SOI구조가 파괴되는 현상과 슬립은 실리콘 기판의 뒷면을 모래타격(sandblast)하여 약 $20{\mu}m$의 거칠기를 가지도록 했을때 방지할 수 있었다. 재결정화된 폴리실리콘의 두께가 두꺼워짐에 따라 재결정화된 박막에서 subboundary의 간격은 넓어지고, 재결정화된 실리콘 두께의 균일성은 보호 산화막이 두꺼울수록 향상된다. 폴리실리콘의 두께를 $1{\mu}m$로 하였을때 subboundary의 간격은 약 $70-120{\mu}m$정도였고 폴리실리콘의 두께가 $1{\mu}m$이고 보호산화막의 두께가 $2.5{\mu}m$일때, 재결정화 후 실리콘의 두게 균일도는 약 ${\pm}200{\AA}$정도였다. Some solutions to several major problems in ZMR such as agglomeration of polysilicon, slips and local substrate melting are described. Experiments are performed with varying polysilicon thickness and capping oxide thickness. The aggmeration can be eliminated when nitrogen is introduced at the capping oxide layer-to-polysilicon interface and polysilicon-to-buried oxide layer interface by annealing the SOI samples at $1100^{\circ}$ in $NH_3$ ambient for three hours. The slips and local substrate melting are removed when the back surface of silicon substrate is sandblasted to produce the back surface roughness of about $20{\mu}m$. The subboundary spacing increases with increasing polysilicon thickness and the uniformity of recrystallized SOI film thickness improves with increasing capping oxide thickness, improving the quality of recrystallized SOI film. When the polysilicon thickness is about $1.0{\mu}m$ and the capping oxide thickness is $2.5{\mu}m$, the thickness variation of the recrystallized SOI film is about ${\pm}200{\AA}$ and the subboundary spacing is about $70-120{\mu}m$.

기억. 학습장애 동물모델 SAMP8에 미치는 알로에(Aloe vera)의 영향 II. SAMP8의 지질대사에 미치는 알로에의 투여효과

최진호,김동우,유제권,한상섭,심창섭,Choi, Jin-Ho,Kim, Dong-Woo,Yoo, Je-Kwon,Han, Sang-Sub,Shim, Chang-Sub 한국생명과학회 1996 생명과학회지 Vol.6 No.3

Aloe(Aloe vera LINNE) has been used as a home medicine for the past several thousand in the world, and has been studied on various chronic degenerative diseases such as atherosclerosis, myocardiac infarction and hypertension. SMAP8, learning and memory impairment animal mode, were fed basic or experimental diets with 1.0% of freeze dried(FD)-Aloe powder for 8 months. This study was designed to investigate the effects of Aloe on body weight gain, grading score of senescence(GSS), triglyceride, total and LDL-cholesterol levels, and atherogenic index in serum of SAMP8, and also designed to investigate the effects of Aloe on cholesterol accumultions in mitochondria and microsome fractions of SAMP8 brain. Body weight gain was consistently lower in aloe group than in control group, but no significantly differences between them. Grading score of senescence resulted ina marked decreases pf 20% in 1.0% Aloe group compared with control group. Administrations of 1.0% aloe resulted ina marked decreases in 15% and 20% of triglyceride and cholesterol levels, respectively, and also significantly decreased in 15% of LDL-cholesterol levels and atherogenic index in serum of SAMP8 compared with control group. Cholesterol accumulations were significantly inhibited in 20% and 10% of mitochondria and microsome fractions of SAMP8 brain, respectively, by administration of 1.0% Aloe. These results suggest that administration of Aloe mau not only effectively inhibit chronic degenerative diseases in serum of SAMP8, but may also improve learning and memory impairments of SAMP8 brain.

동시경화법으로 제조된 복합재료 조인트의 강도 및 파괴모드 연구

최진호,이대길,Choi, Jin-Ho,Lee, Dae-Gil 대한기계학회 1997 大韓機械學會論文集A Vol.21 No.3

The joint design and manufacture of the composite structure have become an important research area because the structural efficiency of the composite structure is often determined by its joint not by its basic structure. The co-cured joint is an efficient joint technique because both curing and jointing for composite structures are achieved simultaneously. In this paper, the torque capacities of the co-cured tubular lap joint with and without knurling of the pyamid type were experimentally measure. From the experimental resuts, it was found that the excess resin played a role as an adhesive in the co-cured tubular lap joint whose steel adherends were not knurled. Also, it was found that the torque capacity of the co-cured joint was increased as the knurling size of the pyramid type on the surface of the steel adherend was increased.

Design of a CMOS Time to Digital Converter with 25ps Resolution

최진호,강진구,Choi, Jin-Ho,Kang, Jin-Ku Institute of Korean Electrical and Electronics Eng 2004 전기전자학회논문지 Vol.8 No.2

This paper describes a CMOS time to digital converter (TDC) that measures the interval between two signals and converts to a digital signal. There are various methods to measure the time interval. But several architectures have a limitation in resolution and in conversion time. Moreover, they have complex algorithms. But the proposed TDC circuit has achieved a high resolution (25ps) by using a high-speed digital sampler and simple algorithm. The sampler detects when input signals comes into the TDC and output is coded. The proposed multiphase clock generator was also implemented to achieve 25p resolution. 본 논문은 두 신호의 시간 차이를 디지털 신호로 변환하는 시간디지털변환기(Time to Digital Converter) 변환기에 대해서 서술하였다. 시간 차이를 측정하는 방법에는 여러 가지가 있으나 변환시간이나 저해상도의 단점을 가지고 있으며 또한 복잡한 구조를 가지는 문제점이 있다. 그러나 본 논문에서 제안한 시간디지털변환기회로는 고속 디지털 샘플러를 사용함으로써 단순한 구조로 높은 해상도(25ps)를 실현할 수 있었다. 입력신호가 시간디지털변환기의 입력으로 들어오면 샘플러가 신호를 검출해내고 레지스터에 의해 처리된 후 코딩블럭에 의해서 코딩되게 된다. 또한 25ps의 해상도를 얻기 위해서 본 논문에서는 다중위상클록발생기를 구현하였다.

대학 계열별 교육수요자의 대학이미지, 대학만족, 전공만족, 학업지속의향의 차이분석

최진호(Jin-Ho Choi) 피터드러커 소사이어티 2023 창조와 혁신 Vol.16 No.4

This study is a secondary study by Choi and Jang(2023), who proved the structural relationship among the factors of academic persistence intentions. Some of the research data were used, and the data were collected through an additional survey. It has been analyzed and identified in an integrated manner. The purpose of this study was to analyze the predictive variables, including academic persistence intentions, such as university image, university satisfaction, and major satisfaction, by major field. As of 2023, university students from freshman to senior or higher enrolled at a women's university in Seoul by the convenience sampling were studied. A total of 527 questionnaires were used for the final statistical analysis, excluding the questionnaires that were not available as analysis data. Excluding major satisfaction, it was found that there were the differences between groups in university image, university satisfaction, and academic persistence intentions by major field. Specifically, it could be interpreted that the subjects of the study were generally highly satisfied with the chosen major, and there was a difference between the arts and sport field and the engineering field for other variables. In order to maintain the continuity of college students' studies to the end, it is necessary to analyze them from the perspective of the university system and structure in terms of specialization of university and majors. Focusing on the university's specialization plan and mid-to long-term development plan, it is necessary to enhance the competitiveness of major, prevent dropout, and support the efforts customized to educational demanders. It would be an important basic data for each university to find the ways to overcome the practical difficulties faced by higher education institutions and devise the customized strategies. 이 연구는 대학 학업지속의향 요인들의 구조적 관계를 증명한 최진호와 장은정(2023)의 2차적 조사이다. 그 연구 자료 일부를 활용하였으며 추가 설문조사를 통해 자료를 수집하여 통합적으로 분석 파악하였다. 연구의 목적은 학업지속의향을포함하여 그 예측변인들인 대학이미지, 대학만족, 전공만족을 대학 계열별로 차이분석하는데 있다. 연구대상은 서울 지역 소재 4년제 여자대학교의 재학생들이였다. 비확률표본추출법(non-probability) 중 편의표본추출법(convenience sampling)을 이용하여 2023학년도에 등록된 1학년에서 5학년 이상을 조사대상으로 하였다. 총 527부의 설문지가 최종 통계분석을 위해 활용되었으며 분석 자료로 이용하기 불가능한 설문지는 제외시켰다. 전공만족을 제외하고는 대학이미지, 대학만족, 학업지속의향은 대학 계열별 집단 간 차이가 있는 것으로 판명되었다. 구체적으로 연구 대상자들은 선택한 전공에 대해서 대체적으로 높게 만족하는 것으로 해석될 수 있으며 그 외의 변인들에 대해서는 예체능계열과 공학계열 간의 차이가 있는 것으로 나타났다. 대학생의 학업지속을 끝까지 유지시키기 위해서는 대학과 전공의 특성화 차원에서 그 대학 제도나 구조 등의 관점에서 분석해야 한다. 그 대학의 특성화 계획과 중장기 발전계획을 중심으로 전공의 경쟁력 제고와 중도탈락 예방 전략, 그리고 교육소비자 맞춤형 지원 노력 등이 필요하다고 할 수 있다. 고등교육기관이 처해있는 현실적 난관을 극복하기 위한 방안을 대학 계열별로 모색하고 맞춤형 전략을 강구하는데 중요한 기초 자료가 될 것이다.