판막 질환에서의 심근 섬유화 : 심근 조직을 이용한 형태학적 연구 및 혈청 생화학적 지표의 분석

강수진,박덕우,송재관,박경민,송종민,강덕현,한기훈,송현,이재원,주석중,송명근,김정선 대한순환기학회 2004 Korean Circulation Journal Vol.34 No.2

급성 심근허혈에 의해 윤발된 승모판 폐쇄부전의 기전에 관한 실험적 연구

강덕현,송현,송재관,김현숙,이재환,임희영,이재원,박성욱,박승정,송명근 대한순환기학회 1999 Korean Circulation Journal Vol.29 No.8

Grade 2, 4 티타늄 마이크로 임플랜트의 식립 및 제거 토크와 식립 후 조직학적 반응의 비교

강승택,권오원,성재현,경희문,박효상 대한치과교정학회 2006 대한치과교정학회지 Vol.36 No.3

마이크로 임플랜트는 순티타늄과 티타늄 합금을 사용하고 있다. 순티타늄의 경우 grade가 낮을 수록 생체적합성은 증가하나 기계적 성질이 낮다. 이에 본 연구에서는 순티타늄 grade 2와 grade 4를 재료로 한 마이크로 임플랜트를 각각 토끼의 다리뼈에 식립한 후 2, 8, 12주의 시간경과에 따른 조직학적 소견의 차이와 식립, 제거 시의 최대토크의 측정으로 그 티타늄 종류에 따른 차이를 살펴보았다. 토끼의 경골에 식립한 티타늄의 종류에 따른 식립시 및 시간의 경과에 따른 제거시의 토크를 측정하여 다음과 같은 결론을 얻었다. 첫째, grade 2와 grade 4간의 식립 시 최대토크의 차이는 없었다. 둘째, 식립 후 2, 8, 12주 후의 제거 시 최대토크 측정에서 전체 마이크로 임플랜트의 그룹간 차이는 없었다. 셋째, 2주에서 8주로 시간이 경과함에 따라 제거 시 최대토크가 유의하게 증가하였으며 8주와 12주간에는 유의한 상관관계가 없었다. 따라서 유지력은 grade 2 티타늄과 비슷하지만 물리적 성질이 더 단단한 grade 4 티타늄을 마이크로 임플랜트 재료로 사용하는 것이 좋은 것으로 생각된다. The purpose of this study was to evaluate the light microscopic features and the maximum insertional and removal torque value of microimplants, made from titanium grade 2 or 4, in the tibia of 6 rabbits. First, the maximum torque values of microimplants at implantation were measured. After 2, 8, and 12 weeks of healing time, the microimplant-containing segments of tibia of 2 rabbits were removed and the maximum removal torque of each microimplant were measured. Comparisons of histologic examination and insertional and removal torque values were carried out for the two groups of microimplants. Removal torque values were significantly increased in both groups after 8 and 12 weeks as compared to 2 weeks after implantation. Other values measured did not show any statistically significant differences and there were no histological differences between grade 2 and 4 titanium. Based on these results, this study showed that there were no significant differences between grade 2 and 4 titanium. It seems better to use grade 4 titanium for making microimplants because grade 4 titanium is mechanically harder than grade 2 titanium and has similar retention.

중 란탄족 산화물의 결합구조와 전기전도성

강영환,최재시,윤기현 연세대학교 대학원 1980 延世論叢 Vol.16 No.2

The electrical conductivity of highly pure polycrystalline Gd₂O₃, Ho₂O₃ and Yb₂O₃ has been measured from 650 to 1050℃ under oxygen pressure range of 10^(-6) to 10² torr. Plots of logσ vs. T at constant oxygen pressure are found to be linear. and the conductivity dependence of oxygen pressure in the high temperature region (750-1050℃) is approximated by σ α po₂1/5.3. This shows that the conduction mechanism is associated with doubly ionized metal vacancies. Fairly low activation energy and the lack of oxygen pressure dependence are found over the temperature range of 650 to 750℃. The conduction mechanism is explained by not metal vacancies, but hopping oxygen ions in the oxides. The sesquioxides exhibit mixed conduction with some ionic conduction and major electronic conduction carriers.

극미세 입자 Aluminosilicate 계 졸의 합성 및 응용 : (Ⅰ) SiO₂및 γ-AIOOH졸의 제조 및 케릭터라이제이션

현상훈,송재권,강범석 연세대학교 산업기술연구소 1993 논문집 Vol.25 No.1

Nanoparticulate silica sols could be synthesized by an interfacial hydrolysis reaction between TEOS and high alkaline water. The silica sols were extremely stable at pH of 8 and their average particle sizes were less than 3 nm, while very unstable between 4 and 5 of pH. The sol particles grew up to about 10 nm within 1 day in the region of pH less than 7. It was found that the silica sol with pH less than 2 was stabilized without further growing after 1 day-aging. The particle size of γ-AlOOH sols synthesized via the modified Yoldas-method could be controlled according to the mole ratio of nitric acid/aluminium tri-sec-butoxide(0.07∼1.0). The stable γ-AlOOH sol with the average particle size of 45 nm, which was prepared using the mole ratio of 0.07, was estimated to be suitable for coating reproducible γ-AlOOH membrane layers with the high specific surface area.

77K와 상온에서 CO(NH₂)₂의 ¹⁴N Pulsed NQR 연구

강재필,박영민,전인,김성재,최숙자,박현진,송승기,서용문 명지대학교 자연과학연구소 1996 자연과학논문집 Vol.13 No.-

77K와 상온에서 CO(NH₂)₂분말 시료의 ??N Pulsed NQR실험을 하여 위와 아래 공명 진동수, 핵 사중극 결합상수, 비대칭 인자, 스핀-스핀 완화시간, 결정 격자 진동에서의 평균 비틀림 진동수, 진동자의 관성 모먼트 등을 구하였다. 공명 진동수의 온도 의존성은 전형적인 Bayer이론의 격자 진동에 의한 주파수 변화를 보였다. Bayer-Kushida이론의 고온근사식을 실험값에 적용하여 OK에서 공명 진동수 ν??와 ν??를 구했으며, 77K와 상온에서의 스핀-스핀 완화시간 T₂를 관측했다. 상온에서 T₂의 감소는 결정 내의 reorientation motion과 관련이 있을 것으로 보인다. Upper and lower resonance frequencies, nuclear quadrupole coupling constants, asymmetry parameters, spin-spin relaxation time, average torsional frequency in the crystal lattice motion and moment of inertia in the oscillator are found for CO(NH₂)₂powder sample by using ??N Pulsed NQR(Nuclear Quadrupole Resonance) technique at 77K and room temperature. Temperature dependence of resonance frequencies showed frequency variation in agreement with the typical Bayer's theory in lattice motion. Resonance frequencies ν?? and ν?? at OK were obtained by fitting the high temperature approximation of Bayer-Kushida theory to the experimental data and spin-spin relaxation time (T₂) was observed at 77K and room temperature. Decrease of T₂at room temperature was explained by the effect of reorientational motion in the crystal lattice.

FIB 신뢰성 평가를 위한 나노패턴의 설계 및 측정

강현욱,이승재,조동우 한국공작기계학회 2005 한국공작기계학회 춘계학술대회논문집 Vol.2005 No.-

FIB (Focused ion beam) system is one of the most important equipments for the nano-scale machining. Various researches have been performed, since it can etch the material and deposit 3-D structure with high-aspect-ratio in the nanometer scale. In spite of those researches, the definite method for the reliability of FIB system has not been reported. In this paper, we proposed the reliability assessment method through nano-pattern fabrication. In the fabricated nano-pattern, the characteristics of FIB system are included. Using this effect, we tried to assess the FIB reliability. First, we suggested reliability assessment items and nano-patterns. And, to know the suitableness of the proposed method, we fabricated several nano-patterns using Nova200(FEI Company) and SMI2050(SEIKO) which are FIB apparatuses. The fabricated nano-patterns are measured with SEM (Scanning Electron Microscope) and compared with designed dimensions. And the compared results showed that the proposed method is suitable for the assessment of FIB system reliability.

Zn를 첨가한 고온초전도체 Y Pr Ba₂Cu₃O 의 Raman 분석

강재필,김성재,박현진,노태호,송승기,박영민,전인 明知大學校 自然科學硏究所 1997 자연과학논문집 Vol.15 No.-

고온초전도제 Y Pr Ba₂Cu₃O 에 Zn를 첨가(x=0.00, 0.05, 0.10, 0.15, 0.20)하여 전이온도 측정, X-ray회절 실험과 Raman 실험을 하였다. Raman 측정결과 다섯 개의 시료가 일반적인 YBCO 초천도체의 Raman 스펙트럼에서 존재하는 다섯 개의 대칭활성모드(115cm¹,150cm¹.340cm¹,440cm¹,504cm¹)가 관측되었다. 이것은 Cu 와 관련된 대칭활성모드의 주파수가 모두 저주파 변위를 나타내어 Zn가 Cu(1)과 Cu(2)에 치환되었음을 의미한다. 저주파 변위 정도는 Zn에 거의 무관했으나, Raman 스펙트럼의 각 피이크의 선폭은 치환된 Zn에 의해 증가했다. 이 결과는 Zn가 Cu자리에 어느 한계 이상은 치환되지 못하고 시료 내에서 불순물상을 형성함을 나타내는 것이다. We measured transition temperature, X-ray diffraction pattern and Raman spectra of Zn added(x=0.00, 0.05, 0.10, 0.15, 0.20) high-T superconductor Y Pr Ba₂Cu₃O All samples have been observed five symmetric activity modes(115cm,150cm¹.340cm¹,440cm¹,504cm¹)which exist in Raman spectrum of general YBCO superconductor. This means Zn is substituted for Cu(1) and Cu(2) due to the fact that symmetric activity mode frequency related with Cu shows low-frequency shift. The degree of low-frequency shift was nearly independent on Zn but line width of Raman spectra peaks were increased by the substituted Zn. This results shows that Zn does not be substituted for Cu-site more than limit value and formes impurity phase in the sample.

의료관계 해부 감정예의 분석적 연구(I) : 1990년 국립과학수사연구소 감정예

姜信夢,李垣兌,李漢榮,尹順雄,全基悳,金相鉉,徐在冠,尹重鎭 大韓法醫學會 1991 대한법의학회지 Vol.15 No.2

A study of 118 autopsy cases associated with medical care in 1990 was present according to the medical department, the mode of treatment and the cause of death. The Pediatrics showed the highest rate (25.4%), followed by the Obstetrics & Gynecology (22.9%), and Internal medicine (20.2%). According to the mode of treatment, medical accidents during operation and anesthesia were 29 cases (24.6%) with highest rate in Obstetrics & Gynecology (13 cases), 38 cases (32.2%) were during medication and/or injection with highest rate in Internal Medicine (18 cases), and 51 cases (43.2%) were during general medical practice with highest rate in pediatrics (19 cases). The most prevalent cause of death was the disease of respiratory system (34.9%, 30 cases) and the diseases of cardiovascular and urogenital system accounted for 31.4% and 11.6% respectively. The main cause of death in Internal medicine was the disease of cardiovascular system (11/24 cases), the respiratory system in pediatrics (15/30 cases) and the disease of urogenital system in Obstetrics & Gynecology (9/27 cases. ) Asphyxial deaths were 7 cases and the death due to adverse drug reaction accounted for 10 cases.

신경회로망에서 뉴런간의 연결도를 이용한 4백 배치 문제 해결 알고리즘

현해진,김덕주,강부식,이기태,임재윤 濟州大學校 工科大學 産業技術硏究所 1993 産業技術硏究報告 Vol.4 No.-

In this paper we have proposed a method for solving a four-coloring problem using adjusted information transmission between adjacent neurons in neural networks. These algorithms are based on McCclloch-Pitts binary neuron model neural networks. If a map shares n regions, a 4×n neural array is used to color a map of n regions where each neuron as a processing element performs it. By programming these algorithm by a C-language in IBM PC 486 DX and adapting it to various examples, we have showed the ability of our system. If one neuron is selected among four neurons, the strength of order three neurons is wakened. So, by transmitting the information of selected neuron, adjacent neurons cannot share the same color.