블리스터 시험법을 이용한 열증착 금박막의 기계적 성질 측정

문호정,함순식,엄윤용,조영호,Moon, Ho-Jeong,Ham, Soon-Sik,Earmme, Yun-Young,Cho, Young-Ho 대한기계학회 1996 大韓機械學會論文集A Vol.20 No.3

Mechanical properties, including Young's modulus, residual stress and rupture strength, of a thermally evaporated gold film have been measured form a blister test. In a theoretical study, the priniple of minimum potential energy and that of virtual work have been applied to the pressurized circular membrane problem, and load-deflection relations have been derived for typical membrane deflection mode of spheroidal shape. In an experimental study, circular gold membranes of 4800 A-thickness and 3.5mm diameter were fabricated by the silicon electropolishing technique. Mecahnical properties of the thin gold films were deduced from the load-deflection curves obtained by the blister test, Young's moduli, obtianed from blister test, have been in the range of 45-70 GPa, while those of bulk gold have been in the range of 78-80 GPa. Residual stresses in the evaporated gold films have been measured as 28-110MPa in tension, The rupture strength of the gold film has turned out to be almost equal to that of dental gold alloy (310-380MPa). It has been demonstrated that the present specimen fabrication method and blister test apparatus have been effective for simultaneous measurement of Young's modulus, residual stress and repture strength of thin solid films. Especially, the electropolishing technique employed here has provided a simple and practical way to fabricate thin membranes in a circular or an arbitrary shape, which could not be obtained by the conventional anisotropic silicon mecromachining technique.

Cu-8.6wt%Al 삽입금속을 사용한 페라이트계 스테인리스강의 아크 브레이징 접합부의 미세조직과 인장성질

조영호,정창은,강명창,강정윤,Cho, Young-Ho,Chung, Chang-Eun,Kang, Myoung-Chang,Kang, Chung-Yun 대한용접접합학회 2011 대한용접·접합학회지 Vol.29 No.4

Microstructures and tensile properties in arc brazed joints of ferritic stainless steel, 429EM using Cu-8.6%Al insert metal was investigated as function of brazing current. The brazing speed was fixed at 800mm/min and brazing current varied in the range of 80A to 120A. The initial phase of filler metal was Cu single phase. However, the insert metal structures of brazed joints was composed of Cu matrix and intermetallic compound such as ${\gamma}_1(Al_4Cu_9)$, and flower-shape Fe-Cr. The fraction of ${\gamma}_1(Al_4Cu_9)$ phase was similar with 80A and 100A brazing currents while that of brazed with 120A was decreased. On the other hand, the fraction of Fe-Cr phase increased with increasing of the brazing current. A reaction layer at the base metal/insert metal interface was observed and this reaction layer was thickened with increasing of the brazing current. In the brazed joints with the current lower than 100A, crack was grew up along the interface which was perpendicular to the tensile stress, and then, passed through the insert metal in the final stage of fracture. As the brazing current increased to 120A, fracture occurred at the base metal.

한쪽 슬관절에서 내측 및 외측에 동시에 발생한 원판형 연골 - 1예 보고 -

조영호,안혁수,장세앙,남승오,Cho, Young-Ho,An, Hyug-Su,Chang, Se-Ang,Nam, Seung-Oh 대한관절경학회 2006 대한관절경학회지 Vol.10 No.1

원판형 연골은 주로 슬관절의 외측에 발생하는 것이 보통이며 드물게 내측에도 발생하는 것으로 알려져 있다. 그러나 내측 및 외측에 동시에 발생한 원판형 연골은 보고된 바가 없다. 저자들은 슬관절 동통을 주소로 내원한 15세 남자에서 자기 공명 영상 및 관절경을 이용하여 한쪽 슬관절에서 내측 및 외측에 동시에 발생한 원판형 연골을 진단하고 양측 모두에 대해 관절경하 부분 절제술로 치료하였기에 보고하고자 한다. Most of discoid menisci are lateral and medial discoid meniscus is very rare. There is no report about simultaneous medial and lateral discoid meniscus in one knee joint. A 15-year-old male patient was diagnosed as having a complete medial discoid meniscus with horizontal tear and intact incomplete lateral discoid meniscus by means of magnetic resonance image and arthroscopy. The patient was treated by arthroscopic partial meniscectomy for both discoid menisci.

백렴 추출물의 Matrix Metalloproteinase-1 발현 저해 효과

조영호,심관섭,김진희,박성민,이범천,표형배,윤여표,박흠대,Cho , Young-Ho,Sim , Gwan-Sub,Kim , Jin-Hui,Park , Sung-Min,Lee , Bum-Chun,Pyo , Hyeong-Bae,Yun , Yeo-Pyo,Park , Hum-Dai 대한약학회 2004 약학회지 Vol.48 No.6

Matrix metalloproteinases (MMPs) are known to play an important role in photoaging by mediating the degradation of extracellular matrix proteins. In this study, to develop a n ew anti-aging agent, we investigated the antioxidant activity and the inhibitory effect of Melothria heterophylla extract on expression of MMP-1 in UVA-irradiated human dermal fibroblasts and MMP-1 activity. The M.heterophylla extract was found to scavenge radicals and reactive oxygen species (ROS) with the $SC_{50}$ values of $13{\mu}g/ml$ against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and $20{\mu}g/ml$ against superoxide radicals in the xanthine/xanthine oxidase system, respectively. UVA-induced MMP-1 expression was reduced about 80% by $100{\mu}g/ml$ of the M.heterophylla extract but MMP-1 Mrna expression was not inhibited. Therefore, we conclude that the M.heterophylla extract significantly inhibits MMP-1 expression at the protein level. Also, the M.heterophylla extract inhibited MMP-1 activity in a dose dependent manner. From these results, we suggest that the M.heterophylla extract can be used as a new anti-aging agent by antioxidant activity, regulation of UVA-induced MMP-1 production, and inhibition of MMP-1 activity.

수용성 아크릴 변성 알키드수지의 합성과 물성 1 . TMPTA 그라프트 공중합에 의한 변성

조영호,노시태 ( Young Ho Cho,Si Tae Noh ) 한국공업화학회 1993 공업화학 Vol.4 No.4

Linseed oil fatty acid(LOFA), phthalic anhydride(PAA) 및 trimellitic anhydride(TMA), trimethylol propane(TMP)을 사용하여 기본적인 유장(oil length) 50%의 중유성 알키드를 합성하고 trimethylol propane triacrylate(TMPTA)를 그라프트 공중합시켜 수용성 TMPTA 변성 알키드수지를 제조하였다. 알키드수지의 산가는 TMA함량으로 제어하였으며, 수용화에는 N,N-Dimethylethanol amine(DMEA)를 중화제로 사용하였다. TMA함량에 따른 산가별 내수성 및 수용화의 최적조건을 산출한 후, TMPTA의 첨가량 변화에 의한 분자량, 유리전이온도, 수용화 후의 점성도, 그라프트율을 측정하였으며, 멜라민 수지를 사용하여 가교시킨 막의 경화온도별 겔분율변화를 조사하였다. TMA첨가량 5.3∼7.0%, 산가 40∼50의 범위에서 알키드 수지의 내수성과 수용화가 가장 좋은 균형을 나타냈으며, 변성 알키드수지의 경우 TMPTA의 양이 증가할수록 분자량, 수용액의 점성도, 겔분율은 증가하였으나, 유리전이온도(Tg)는 감소하였다. 고형분 함량에 따른 점성도 변화는 고형분 40%일 때보다 50%일 때가 점성도가 낮게 나타났으며 중화도에 따른 수용액의 점성도 변화는 중화도가 높을수록 점성도는 낮아지나 중화도 100∼110 사이에서는 거의 변화가 없음을 알 수 있었다. TMPTA의 그라프트율은 TMPTA의 첨가량이 4wt%인 때가 가장 높게 나타남이 확인되었다. The basic medium oil modified alkyd resin was synthesized from linseed oil fatty acid(LOFA), phthalic anhydride(PAA), trimellitic anhydride(TMA), and trimthylol propane(TMP) by condensation polymerization at 230℃. TMPTA modified water-reducible alkyd resins were synthesized with TMPTA graft copolymerization onto the basic resin at 180℃. Acid value of the resin was controlled by the addition of TMA and N,N-Dimethylethanol amine(DMEA) was used as an neutralizing agent to prepare water-reducible alkyd. To evaluate the optimum formulation for anionic alkyd resin, water proofness and water reducibility were estimated from the acid value or TMA contents. The effect of TMPTA on the graft copoymerization of the resin was studied by measuring molecular weight, glass transition temperature(Tg), viscosity, and gel contents. The suitable balance of water proofness and water reducibility of the resin was obtained at range of 5.3∼7.Owt.% of TMA contents or 40∼50 of acid value of basic resin. The molecular weight, viscosity, and gel contents of water-reducible alkyd resin were increased according to the TMPTA graft copolymerization, but Tg was decreased.

과칼륨혈증의 심전도변화와 중조(重曹)투여가 이에 미치는 영향

조영호,채의업,Cho, Young-Ho,Chae, E-Up 대한생리학회 1982 대한생리학회지 Vol.16 No.1

과칼륨혈증(Hyperkalemia)시의 심전도의 변화를 흰쥐에서 관찰하고 특히 평균 QRS 전기축의 변화, P-Q 및 Q-T 간격의 변화와 중조$(NaHCO_3)$투여에 의한 치료적 효과가 흰쥐에 심전도 변화에 미치는 영향에 대하여 관찰하였다. 실험동물을 4군으로 나누고 정상대조군, KCl만 투여군, $NaHCO_3$만 투여군 및 KCl 투여 1시간 반후 $NaHCO_3$투여군에 대해 그 소견을 비교 고찰하였다. KCl투여군에서 분시 심박수는 초기에 급속히 감소하여 그대로 유지되며 후기에는 급격히 서맥이 초래되며 심장이 정지된다. 평균 QRS 전기축은 후기에 좌측으로 편의한다. T파의 파고는 일시적으로 증가하였으나 후기에는 변화가 없었다. P-Q 간격은 초기에 연장되다가 말기에 회복되었으며 Q-T 간격도 초기에 연장 되었다가 후기에 점차 회복되는 경향을 보였다. $NaHCO_3$만의 투여군은 심박수가 초기에 급격히 감소하나 후기에는 반대로 미미한 회복 경향을 보인다. 평균 QRS 전기축은 초기에 변화가 없었고 말기에는 좌측으로 편의하였으며 T파의 파고는 큰 변화가 없었다. 또한 P-Q간격 및 Q-T 간격은 초기에 연장되다가 말기에 단축되었다. KCl투여 1시간 반 후 과칼륨혈증상태에서 $NaHCO_3$를 투여한 군에서는 심박수의 회복은 없었다. 평균 QRS 전기축의 우측편의 경향과 감소되었던 R파고의 증가와 증가되었던 T파의 파고 회복경향이 있었다. P-Q 간격은 계속 연장되었으며 Q-T 간격은 중조투여직전에 비하여 큰 변화가 없었다. The effects of $NaHCO_3$ on the electrocardiogram of rats were studied in the induced hyperkalemia. The subjects were divided into 4 groups: the group 1 was normal control and the data on this normal control had teen obtained from the following three groups before administration of KCl or $NaHCO_3$, the group 2 (KCl) was administered 40 ml per kg body weight of the 10 per cent KCl solution, the group 3 $(NaHCO_3)$ was administered 40 ml per kg body weight of the 10 per cent $NaHCO_3$ solution, and the group 4 $(KCl+NaHCO_3)$ was received 10 per cent KCl, which was followed by administration of 10 per cent $NaHCO_3$ at one and half hours later. In KCl, the heart rate was decreased rapidly, and then maintained its level, later rapid decreasing heart rate was followed by the cardiac stand still. The mean electrical axis of QRS complex became progressively deviated to the left. The amplitude of T wave was increased transiently but was not changed thereafter. There was prolongation of the P-Q interval and the Q-T interval at the beginning and then they were shortened. In $NaHCO_3$, the heart rate was decreased rapidly at the beginning, later showed a tendency of recovery. The mean electrical axis of QRS was not changed initially, but later became deviated to the left. The amplitude of T wave was not changed. There was prolongation of the P-Q interval and the Q-T interval at the beginning and then they were shortened. In $KCl+NaHCO_3$, there were a tendency of recovery of both the amplitude of the T wave and the electrical axis of the QRS complex after administration of $NaHCO_3$ but the heart rate was not recovered. There was prolonged P-Q interval, but the Q-T interval was relatively unchanged.

연구논문 - 고분자 : 수분산성 Oil Free 알키드 수지의 합성과 물성 3. ε- Caprolactone 및 TMP 에 의한 변성

조영호,노시태 ( Young Ho Cho,Si Tae Noh ) 한국공업화학회 1994 한국공업화학회 연구논문 초록집 Vol.1990 No.3

수분산성 변성 알키드 수지의 합성과 특성 3 . ε- 카프로락톤 변성 Oil Free 알키드의 합성과 물성

조영호,노시태 ( Young Ho Cho,Si Tae Noh ) 한국공업화학회 1995 공업화학 Vol.6 No.3

트리메틸올프로판(TMP), 1, 6-헥산디올(1, 6-HD) 및 이소프탈산(IPA)을 사용하여 기본적인 분지형 oil free 알키드를 합성하고, ε-카프로락톤을 개환 중합시켜 ε-카프로락톤 변성 알키드 수지를 합성하였다. 다시 트리멜리트산무수물(TMA)을 반응시켜 음이온성기를 도입하고, N, N-디메틸에타놀아민(DMEA)으로 중화시켜 수분산화하여, ε-카프로락톤 변성 수분산성 oil free 알키드를 제조하였다. ε-카프로락톤 변성 알키드 수지의 상온(25℃)에서의 수용화 능력을 조사하기 위하여, TMP의 함량을 조절하여 알키드 수지를 합성하였으며, 상온(25℃)에서 투명한 수분산 용액이 되는 알키드 수지 영역에서 ε-카프로락톤을 첨가하여 개환 반응시켰다. ε-카프로락톤 모노머의 첨가량 변화에 의한 구조분석, 분자량, 유리전이온도, 반응율, 점성도 등의 물성 변화를 조사하였으며, 멜라민수지를 사용하여 가교 시킨 도막의 연필경도와 가공성 등의 변화를 조사하였다. TMP의 함량이 증가할수록 상전이 온도는 낮아졌으며, ε-카프로락톤의 첨가량이 증가할수록 분자량은 크게 변화하지 않았고, 점성도 변화는 고형분 55∼60wt%에서 감소하였다가 다시 증가하는 특성을 보였다. 반면에 유리전이온도는 낮아졌으며, 반응율은 촉매를 사용한 경우에 89.6∼92.7%였으며, 멜라민 경화막의 연필경도는 낮아지나 가공성은 증가하였다. The basic ε-caprolactone modified oil free alkyd resin was synthesized from trimethylol propane(TMP), 1, 6-hexane diol(1, 6-HD), isophthalic acid(IPA) and trimellitic anhydride(TMA) by condensation polymerization at 220℃. ε-Caprolactone modified water-reducible oil free alkyd resins were synthesized with ε-caprolactone ring opening reaction onto the basic resin at 150℃. N, N`-Dimethylethanol amine(DMEA) was used as a neutralizing agent to prepare of the water-reducible oil free alkyd resin. The effect of TMP was studied by measuring clear point by using DSC. The effect of ε-caprolactone on the ring opening reaction of the resin was studied by measuring molecular weight, glass transition temperature(T_g), reaction efficiency, viscosity and flexibility, pencil hardness of melamine cured film. The clear pont was decreased according to the contents of TMA increased. The molecular weight was not much changed, and T_g was decreased according to the ε-caprolactone contents in the oil free alkyd resin increased. The viscosity was lower when the solid contents reached 55∼60wt% than that of 40∼45wt% content and the reaction efficiency was the range of 89.6∼92.7%. The pencil hardness of melamine cured film was decreased, but flexibility was increased according to the ε-caprclactone contents in the oil free alkyd resin increased.

한국인(韓國人)의 유치(乳齒) 맹출시기(萌出時期)에 대(對)한 연구(硏究)

조영호,Cho, Young-Ho 대한소아치과학회 1977 大韓小兒齒科學會誌 Vol.4 No.1

The author carried out to determine the normal range of eruptive time, average age and order of eruption of primary teeth in korean infants. The examimation was given to 1757 healty infants(Male 1032, female 725) from afterbirth 4 months to 32 months. The results was as fallows. 1. The eruption of primary teeth was 0.57 months earlier in male than in female. 2. The average month of eruption of primary teeth was as follows; Upper primary central is $9.66{\pm}0.19$ months Upper primary lateral is $11.58{\pm}0.18$ months. Upper primary canine is $18.06{\pm}0.32$ months. Upper first primary molar is $16.45{\pm}0.29$ months. Upper second primary molar is $24.28{\pm}0.51$ months. Lower primary central is $7.50{\pm}0.12$ months. Lower primary lateral is $12.87{\pm}0.16$ months. Lower primary camine is $18.82{\pm}0.34$ months. Lower first primary molar is $17.66{\pm}0.37$ months. Lower second primary molar is $23.89{\pm}0.51$ months. 3. The eruptive order of the korean is different from that of the American and same to that of Japanese. 4. There is no significant right and left arch. 5. Generally, the eruption of primary teeth on the upper is 1.08 months earlier than on the lower; but the upper central is 2.16 months later than the lower and the upper second primary is 0.39 months later than the lower.

수용성 아크릴 변성 알키드 수지의 합성과 물성 2 . MA 및 TMPTA 공중합체에 의한 변성

조영호,강기준,노시태 ( Young Ho Cho,Ki Joon Kang,Si Tae Noh ) 한국공업화학회 1994 공업화학 Vol.5 No.4

Linseed oil fatty acid(LOFA), phthalic anhydride(PAA) 및 maleic anhydride(MA), trimethylol propane(TMP)을 사용하여 기본적인 유장(oil length) 50%의 중유성 기본 알키드를 합성하고 trimethylol propane triacrylate(TMPTA)를 그라프트 공중합시켜 MA/TMPTA 변성 알키드 수지를 제조하였다. 수지의 산가는 MA 첨가량으로 제어하였으며, 수용화에는 N,N-dimethylethanol amine(DMEA)를 사용하였다. TMPTA의 첨가량 변화에 의한 분자량, 유리 전이온도, 수용화 후의 점성도 및 그라프트율을 측정하였으며, 가교도막의 경화온도별 겔분율 변화를 조사하였다. 또한 멜라민 수지 경화 도막의 내열성, 내자외선성, 내수성 및 저장 안정성을 측정하고, TMA/TMPTA 변성 알키드 수지의 물성과 비교하였다. TMPTA의 첨가량이 증가할수록 수용화 후의 점성도, 겔분율, 그라프트율 및 분자량이 증가하였으며, 유리 전이온도(Tg)는 감소하였다. 고형분 함량에 따른 점성도 변화는 고형분 30%일 때보다 40%일 때가 더 낮게 나타났으며, 중화도에 따른 점성도 변화는 중화도가 높을수록 낮은 점성도를 나타내었다. 내열성, 내자외선성, 내수성은 MA/TMPTA 변성 알키드 수지가 TMA/TMPTA 변성 알키드 수지보다 우수하였으나, 저장 안정성은 TMA/TMPTA 변성 알키드 수지가 우수함을 알 수 있었다. The basic medium oil modified alkyd resin was synthesized from linseed oil fatty acid(LOFA), phthalic anhydride(PAA), maleic anhydride(MA) and trimethylol propane(TMP) by condensation polymerization at 230℃. MA/TMPTA modified water-reducible alkyd resins were synthesized with TMPTA graft copolymerization onto the basic resin at 180℃. Acid value of the resin was controlled by the addition amount of MA and N,N-dimethylethanol amine(DMEA ) was used as a neutralizing agent to prepare of the water-reducible alkyd resin. The effect of TMPTA on the graft copolymerization of the resin was studied by measuring molecular weight, glass transition temperature(Tg), viscosity, graft efficiency, and gel contents of melamin cured film Heat resistance, UV resistance, and water resistance of cured film of MA/TMPTA modified resin was compared to those of TMA/TMPTA modified alkyd resin. The molecular weight, viscosity gel contents and graft efficiency of water reducible alkyd resin were increased according to the TMPTA graft copolymerization, but Tg was decreased. The viscosity was lower when the solid contents reached 40% than that of 30% content and also became lower with the extent of neutralization ratio. The heat resistance, UV resistance and water resistance of the MA/TMPTA modified alkyd resis were better than those of TMA/TMPTA modified alkyd resin but the storage stability of the TMA/TMPTA alkyd resis was better than that of MA/TMPTA modified alkyd resin.