24시간 혈압 감시를 통한 만성 뇌졸중 환자에서의 야간 혈압 강하 현상의 연구

정산,이병철,유경호,정승철,김성민,권기한,황성희 대한신경과학회 1996 대한신경과학회지 Vol.14 No.4

모래쥐의 양측 목동맥차단에 의한 전뇌허혈이 대뇌겉질 혈관의 미세순환에 미치는 영향

고운산,황성희,이병철 대한신경과학회 1998 대한신경과학회지 Vol.16 No.5

Sodium Trans-Bis(methyliminodiacetato)Chromate(Ⅲ)의 두가지 다른 空間群 P1￣와 A2/n間의 相互 變換

李珍昊,宋柱昊,崔成山,郭相姬,吳美蘭,박성진,李揆旺,徐廷善,徐日煥 충남대학교 1996 忠南科學硏究誌 Vol.23 No.1

The structure of sodium trans-bis(methyliminodiacetato) chromate(Ⅲ), C_10H_14O_8N_2CrNa, has been elucidated with two space groups P 1-; a=8.9856(6), b=13.308(1), c=6.261(1)Å, α=76.38(1), β=110.361(9), r=107.394(6)˚, V=662(2)Å^3, Z=2, μ=0.47mn^(-1), d=1.831Mg/㎥, R=0.0295 for 1901 independent reflections with F^2>2σ(F^2), and A2/n; a=13.65(5), b=6.261(1), c=16.85(6)Å, β=113.05(1)˚, V=1324(7)Å^3, Z=4, R=0.0287 for 1013 independent reflections with F^2>2σ(F^2). There are two different asymmetric half molecules in triclinic system and one asymmetric half molecule in monoclinic system. The structures of three different molecules are very similar in conformations. The four carboxyl O atoms and the two imino N atoms in each molecule produce a distorted octahedral coordination geometry around the Cr atom. The average distances of Cr-O(carboxyl) and Cr-N(imino) are 1.956 and 2.061Å respectively. Molecules are held together by ionic forces. In this paper, it has been also shown that the cell constants, Miller indices, atomic coordinates, lattice directions and reciprocal lattices of the two space groups can be mutually transformed.

C.V.D. 방법에 의한 Cd_0.78Zn_0.22 S박막 성장과 광전기적 특성연구

유상하,이상렬,홍광준,서상석,김혜숙,전승룡,윤은희,문종대 조선대학교 기초과학연구소 1993 自然科學硏究 Vol.16 No.1

We had grown Cd_0.78Zn_0.22S polycrystal thin films on slide substrate using chemical vapour deposition(CVD) method. We measured X-ray diffraction patterns in order to study Cd_0.78Zn_0.22S polycrystal structure. We studied its band gap using transmission curves and photocurrent and also analyzed photoluminescence using configurational coordinate model. We measured Hall effect·on this sample by Van der Pauw method and studied on carrier density and mobility depending on temperature.

취성재료의 미소압입시 균열전파의 유한요소해석

조성산,이정현 弘益大學校 科學技術硏究所 1998 科學技術硏究論文集 Vol.9 No.1

Stress around the edge of penny-shaped lateral crack in the residual stress fields in elastic perfectly-plastic half-spaces indented by a rigid cone are analyzed using finite element technique. The stresses are characterized and interpreted to investigate the crack growth behavior with the aid of linear elastic fracture mechanics. The influence of material properties on the crack growth behavior is also examined. Continuing growth of the crack after removal of indentation load is explained based on the variation of crack growth driving force with crack size. Furthermore, it is demonstrated that the change in the crack propagation direction with the growth is due to the change in the crack growth mechanism.

혈소판 Cyclic Nucleotide, Inositol Trisphosphate 및 [Ca^(++)]_(i)의 응집반응성 변동에 대한 항우울성 약물의 영향

최상현,박석산,이민수,전보권,천연숙 고려대학교 의과대학 1992 고려대 의대 잡지 Vol.29 No.3

The pharmacodynamic mechanisms of available antidepressant drugs have not yet clarified. Major depression is common and may more frequently occur for the first time in the eldery, and the incidence of thromboembolism is increased with advancing of age. And many studies have shown an usefulness of platelet as models of monoaminergic neurons. Therefore, this paper. deals with the anti-platelet activity of antidepressant drugs in view of the common action in platelet signal-transduction system of three antidepressants showing different modes of action. The IC_(50)s of amitriptyline alprazolam. and rolipram were 1.39×10^(-4), 2.63×10^(-4), and 8.11×10^(-4)M. respectively, and that of each of the reference drugs : sodium nitroprusside. chlorpromazine. and spermine were 1.26×10^(-6), 5.76×10^(-5) and 4.28 ×10^(-3)M. Rolipram and alprazolam produced the significant increase of platelet cGMP level with slight cAMP increase. showing their selectivity on typeⅡ cGMP-specific PDE. Spermine and antidepressants, particularly used in this study induced the marked increase of platelet IP_(3) level with the anti-platelet and [Ca^(++)]_(i),-decreasing activities. These findings suggest that the mechanism of action of antidepressant drugs seems to be related with their enhancing property of the neuronal IP_(3)-mediated signalling. and that the paradoxical mode of their actions on platelet metabolisms of [Ca^(++)]_(i) and IP_(3) may be a clue of the uncovering of a new cellular [Ca^(++)]_(i)-regulating mode.

감염 조절용 차단막의 두께가 광중합기의 중합광에 미치는 영향

장훈상,이석련,홍성옥,류현욱,송창규,민경산 大韓齒科保存學會 2010 Restorative Dentistry & Endodontics Vol.35 No.5

연구목적: 본 연구는 감염 조절용 차단막을 여러 겹으로 사용했을 때 광중합기의 광강도와 파장, light diffusion 등에 미치는 영향에 대해 조사하였다. 연구 재료 및 방법: 감염 조절용 차단막은 투명 랩 (크린랩)을 사용하였고 광중합기는 할로겐 광중합기 (Optilux 360)와 LED 광중합기 (Elipar FreeLight 2)를 사용하였다. 차단막을 1겹, 2겹, 4겹, 8겹으로 광중합기의 광섬유말단을 감싸고 휴대용 광강도 측정기 (Cure Rite)로 광중합기의 광강도를 측정하였다. 광중합기를 주문제작한 optical breadboard에 고정시킨 후 휴대용 spectroradiometer (CS-1000)를 이용하여 광중합기의 파장을 측정하였고, DSLR (Nikon D70s)을 이용하여 광중합기의 light diffusion을 사진 촬영하였다. 결과: 광강도 측정 결과는 차단막의 두께가 증가할수록 광강도가 유의하게 감소하였으나 할로겐 광중합기에서 1겹과 2겹 사이에는 유의차가 없었으며, 4겹 이상의 차단막을 투과할 때 광강도가 더 많이 감소하였다. 여러 겹의 차단막을 투과한 광중합기의 전체적인 파장 형태와 peak wavelength의 변화는 관찰되지 않았다. Light diffusion 사진 촬영 시, LED 광중합기에서는 차단막의 두께가 미치는 영향이 없었으나 할로겐 광중합기에서는 차단막을 4겹 사용했을 때부터 중합광이 조사되는 각도가 감소하기 시작하여 8겹 사용했을 때 통계적으로 유의하게 감소하는 것을 볼 수 있었다 (p < 0.05). 결론: 광중합형 복합레진을 광중합할 경우 감염 조절용 차단막이 찢어지는 경우를 대비하여 1겹으로 사용하기 보다는 2겹으로 사용하는 것이 환자간의 교차감염을 예방하는데 유리할 것으로 사료된다. Objectives: This study investigated the effect of infection control barrier thickness on power density, wavelength, and light diffusion of light curing units. Materials and Methods: Infection control barrier (Cleanwrap) in one-fold, two-fold, four-fold, and eightfold, and a halogen light curing unit (Optilux 360) and a light emitting diode (LED) light curing unit (Elipar FreeLight 2) were used in this study. Power density of light curing units with infection control barriers covering the fiberoptic bundle was measured with a hand held dental radiometer (Cure Rite). Wavelength of light curing units fixed on a custom made optical breadboard was measured with a portable spectroradiometer (CS-1000). Light diffusion of light curing units was photographed with DSLR (Nikon D70s) as above. Results: Power density decreased significantly as the layer thickness of the infection control barrier increased, except the one-fold and two-fold in halogen light curing unit. Especially, when the barrier was four-fold and more in the halogen light curing unit, the decrease of power density was more prominent. The wavelength of light curing units was not affected by the barriers and almost no change was detected in the peak wavelength. Light diffusion of LED light curing unit was not affected by barriers, however, halogen light curing unit showed decrease in light diffusion angle when the barrier was four-fold and statistically different decrease when the barrier was eight-fold (p < 0.05). Conclusions: It could be assumed that the infection control barriers should be used as two-fold rather than one-fold to prevent tearing of the barriers and subsequent cross contamination between the patients.

취성재료의 3개체 연삭가공시 응력해석

조성산,이정현 弘益大學校 科學技術硏究所 1997 科學技術硏究論文集 Vol.8 No.-

Subsurface stresses of workpiece indented by a rotating abrasive in lapping processes are analyzed using two dimensional finite element technique. The workpiece is assumed as an elastoplastic half-space, the abrasive as a rigid rectangular bar, and the lap as a rigid half-space. The stresses in the case of indentation is also analyzed to examine the effects of tangential traction. It is demonstrated that an approximately circular plastically-deformed region is evolved below the contact point and that a local maximum of tensile principal stress occurs at the intersection between the boundary of plastically-deformed region and the extension of diagonal line of abrasive. Moreover, the local maximum value occurring in a loading period is greater than that in the residual stresses, implying that subsurface cracks can be nucleated in the loading period.

재생 폴리에텔렌의 기계적 성질 : 충격 보강재 효과에 대하여

계형산,강경민,박종훈,정융권,이상환 목원대학교 자연과학연구소 2002 自然科學 硏究論文集 Vol.11 No.2

본 연구는 재활용이 가능한 폴리에틸렌 필름 등에 비산회(Fly Ash) 등의 충진재를 사용하여, 신재와 물성을 비교하여 재생 PE의 재활용 가능성 및 사용 가능한 충진재의 종류를 알아보는데 그 목적이 있다. 또한 본 연구에서는 치합형 동방향 회전 이축 압출기(Fully Intermeshing Co-rotating Twin Screw Extruder)를 이용해서 재생 Polyethylene에 비산회 및 다양한 충진재(filler)를 첨가하여 ASTM에 의거하여 충격시편을 만들었고, 각 충진재의 무게비에 따른 충진재 충격 시험을 하였으며 Capillary Rheometer를 이용하여 유변학적인 성질을 분석해 보았다.

경추 손상후 사망례에 대한 분석

정호성,김상은,이준형,박철완,이 근 大韓應急醫學會 1996 대한응급의학회지 Vol.7 No.1

Mortality after cervical spine injury(CSI) is reported as high as 10∼30%, and it is intimately related to the initial management and cardiopulmonary function. We analyzed the cause of death for 29 patients who expired at Chung Ang Gil Hospital after CSI between 1990 and 1994. Of 198 patients with CSI, 43 patients(21m7%) died. Except 14 cases with concomitant fatal head injury and/or multiple systemic injuries, the mortality rate of CSI was 14.6%. Male to female ratio was over 6:1. Fourth to sixth decades constituted 69.0%. Common causes of CSI were traffic accidents(58.6%) and fall/slip(34.5%). The level of CSI was above C5(upper cervical group: UCG) in 65.5%, and below C4(lower cervical group: LCG) in 34.5%. Most of them(86.2%) died within four weeks after CSI. Early death(within 7 days) was more common in the UCG(57.9%) than the LCG(20.0%). Associated injuries were found in 72.4%, and the head injury was the most common one. The higher the Injury Severity Score(ISS), the earlier the patients expired(Fisher`s test, P<0.05). On arrival, hypotension(systolic blood pressure below 90mmHg), bradycardia(less than 60/min), and respiratory arrest was found in 31.0%, 34.5% and 17.2%, respectively. The episode of bradycardia was found in 58.6%. It was more common in cases of early death(69.2%) than those of the late death(50.0%). Hypoxia, hypercarbia, and acidosis was observed in 20.7%, 17.2%, and 51.7%, respectively. Respiratory failure was responsible for the majority(89.7%) of death. In UCG and the cases of the early death, primary respiratory dysfunction was the main cause of death, while in LCG and the cases of the late death, pulmonary complication was the major reason(Fisher`s test P<0.01, P<0.01, respectively).