• 한국항공우주학회지
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• 제48권2호
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• pp.99-108
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• 2020

항공기 결빙 분야에서 표면 조도는 대류 열전달을 강화하고 국소 액적 부착률(Local Collection Efficiency)을 변화시킨다는 점에서 매우 중요한 요소로 받아들여지고 있다. 이에 따라 최근 결빙실험 분야에서는 표면 조도 형성과정 데이터를 획득하기 위한 노력이 진행되고 있다. 한편, 이러한 실험은 데이터 측정의 어려움으로 인해 주로 저속 결빙조건에서 수행되고 있다. 그러나 저속조건이 표면 조도의 최종 형상에 미치는 영향은 아직 거의 알려진 바가 없다. 본 연구는 저속 결빙조건에서 실험을 수행하고, 획득한 표면 조도 데이터와 결빙조건과의 연관성을 분석하였다. 분석 방법으로는 기존 고속조건 실험에 활용되는 지배 파라미터를 이용하였으며, 표면 조도의 경향성을 기존 고속 실험 결과와 비교하였다. 표면 조도 크기는 기존에 알려진 경향성과 잘 일치했지만, smooth zone 폭은 차이를 보이는 것을 확인할 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.361-365
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• 2003

Planar Inductively Coupled Plasma (PICP) etching of InGaP was performed in $BCl_3,\;BCl_3/Ar\;and\;BCl_3/Ne$ plasmas as a function of ICP source power ($0\;{\sim}\;500\;W$), RIE chuck power ($0\;{\sim}\;150\;W$), chamber pressure ($5\;{\sim}\;15\;mTorr$) and gas composition of $BCl_3/Ar\;and\;BCl_3/Ne$. Total gas flow was fixed at 20 sccm (standard cubic centimeter per minute). Increase of ICP source power and RIE chuck power raised etch rate of InGaP, while that of chamber pressure reduced etch rate. We also found that some addition of Ar and Ne in $BCl_3$ plasma improved etch rate of InGaP. InGaP etch rate was varied from $1580\;{\AA}/min$ with pure $BC_3\;to\;2800\;{\AA}/min$ and $4700\;{\AA}/min$ with 25 % Ar and Ne addition, respectively. Other process conditions were fixed at 300 W ICP source power, 100 W RIE chuck power and 7.5 mTorr chamber pressure. SEM (scanning electron microscopy) and AFM (atomic force microscopy) data showed vertical side wall and smooth surface of InGaP at the same condition. Proper addition of noble gases Ar and Ne (less than about 50 %) in $BCl_3$ inductively coupled plasma have resulted in not only increase of etch rate but also minimum preferential loss and smooth surface morphology by ion-assisted effect.

• 멤브레인
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• 제27권1호
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• pp.43-52
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• 2017

분리막 오염을 감소시키고 투과유속 향상을 위하여 관형분리막 모듈 내에 공기 분사노즐관을 삽입시켰다. 분리막의 평균 기공크기는 $0.1\;{\mu}m$이며 이스트를 오염물질로 사용하였다. 모든 투과실험은 노즐관을 모듈에 장착하고 공기를 주입하지 않는 실험을 먼저 실시하고 연속해서 공기를 주입하는 투과실험을 하였다. 그 다음 노즐관을 제거한 후 공기를 주입시키지 않으면서 투과유속을 측정하였다. 측정된 투과유속은 공기주입 효과를 분석하기 위하여 비교하였다. 공기주입에 대한 투과유속은 거의 일정하거나 증가하였다. 노즐관이 장착되고 공기 주입을 하지 않을 경우의 투과유속이 빈 관형 모듈의 경우보다 높았다. 운전압력을 0.4 bar까지 감소시키면 노즐관이 장착되지 않는 경우와 비교하여 공기를 주입할 경우 투과유속이 21%까지 향상되었다. 기체량이 증가하여 기/액체 2상 흐름이 stratified-smooth에서 intermittent 상태로 변화됨에 따라서 공기 주입에 의한 투과유속은 30% 이상으로 증가하였다.

• 대한지구과학교육학회지
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• 제9권1호
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• pp.97-105
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• 2016

The purpose of this study was to examine the effects of storytelling skill on science concept and science learning motivation. For this study the 5 grade, 2 class was divided into a research group and a comparative group. The class was pre-tested in order to ensure the same standard. The research group had the science class with storytelling skill, and the comparative group had the class of the teacher centered lectures on 11 classes in 8 weeks. The storytelling skill was focused on set the astronomical target wants to set up a story, through the small group discussion, present subject of the story, set the protagonist of the story for smooth configuration of the story, in order to smooth the flow of the story, make up a story around a hero, to make a clear story, decorated with pictures, shapes, graphs, etc, group story, complete with an astronomical(saints) in storytelling. To prove the effects of this study, science concept was split up according to knowledge, inquiry, attitude. Also, science learning motivation consisted of assignment is worth, learning beliefs about control, self efficacy. The results of this study are as follows. First, using storytelling skill was effective in science concept. Second, using storytelling skill was effective in science learning motivation. Also, after using storytelling skill was good reaction by students. As a result, the elementary science class with storytelling skill had the effects of developing science concept and science learning motivation. It means the science class with storytelling skill has potential possibilities and value to develop science concept and science learning motivation.

• Biomolecules & Therapeutics
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• 제2권4호
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• pp.336-342
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• 1994

The general pharmacological properties of EPO were investigated in various animals administering intravenously and in vitro system. The results were as follows. 1. Central nervous system: EPO at doses of 70, 700, 7000 U/kg showed no effect In mice on general behavior, on strychnine- and pentetrazol-induced convulsion and on acetic acid-induced writhing syndrome. The hexobarbital-induced sleeping time in mice was slightly reduced by EPO at a dose of 7000 U/kg but did not change at doses of 70, 700 U/kg. The body temperature in rats was slightly decreased by EPO at doses of 700, 7,000 U/kg but the change was in normal physiological range. 2. Respiratory and cardiovascular system: EPO showed no effect on respiratory rate, blood pressure, heart rate, femoral blood flow, and electrocardiogram in anesthetized dogs at doses of 70, 700, 7000 U/kg. 3. Smooth muscle: EPO at concentrations of 70, 700 U/ml had no effect on the contractile response of isolated guinea pig ileum to histamine and acetylcholine. 4. Water and electrolytes excretion: EPO at dose above 700 U/kg increased urine volume in rats but did not affect the concentrations of $Na^{+},\;K^{+},\;Cl^{-}$ in urine. 5. Gastrointestinal system: EPO(70, 700, 7000 U/kg) had no effect on the intestinal charcoal meal propulsion 6. Blood coagulation system: The administration of EPO(70, 700, 7000 U/kg) had no effect on the plasma prothrombin time(PT) and activated partial thromboplastin time(APTT) in mice. Platelet aggregation induced by ADP and collagen was not influenced by EPO(70 U/ml, 700 U/ml). The overall results obtained indicated that EPO exerts almost no serious pharmacological effect even at a 100-fold clinical dose(7000 U/kg).

• 대한본초학회지
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• 제24권4호
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• pp.77-86
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• 2009

Objectives : The proliferation and migration of human aortic smooth muscle cells (HASMC) in response to activation by various stimuli plays a critical role in the initiation and development of atherosclerosis. This study was conducted to examine the effects of Nelumbo nucifera leaves (NNL) on the proliferation and migration of HASMC. Additionally, the mechanisms involved in any observed effects were also evaluated. Methods : Apoptotic cells were measured by staining with FITC-labeled annexin V, followed by flow cytometric analysis. The expression level of apoptosis related proteins was confirmed by western blot. And MMP-9 activity was measured by gelatin zymography and MMP-9 expression was measured by ELISA Results : NNL completely inhibited the proliferation of HASMC via induction of the expression of apoptotic proteins including annexin V, cleaved poly ADP-ribose polymerase (PARP), and caspase-3 and -8. NNL treatment resulted in the release of cytochrome c into cytosol, a loss of mitochondrial membrane potential, a decrease in Bcl-2 and Bcl-xL and an increase in Bax expression. NNL also blocked HASMC migration via suppression of MMP-9. Conclusions : Taken together, these results indicate that NNL has the potential for use as an anti-artherosclerosis agent.

• 동의생리병리학회지
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• 제20권6호
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• pp.1431-1441
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• 2006

Following conclusions were drawn from the examination of the usage of semen persicae and fols carthami from the view of Hyungsang Medicine. Semen persicae is used to vitalize the blood flow and eliminate the blood stagnation of the whole body in ${\ulcorner}$Donguibogam${\lrcorner}$, and therefor it is used for the blood flow of the heptal meridian and sometimes the intestinal meridian. Flos carthami is applied to vitalize the blood flow, remove obstructions in meridians, eliminate the blood stagnations, and stop the pain in ${\ulcorner}$Donguibogam${\lrcorner}$, therefore used in such symptoms of blood flow of the heptal meridian as amenorrhea, spasm of muscles, and coldness of the genitals. Also is applied in those cases of exhaustion, perspiration, and in digestive remedies which belong to the symptoms of cardiac blood flow. And it is used for dryness of the skin in which case the blood should be developed and malaria for the elimination of the blood stagnation and production of new blood. The combination of semen persicae and flos carthami is applied to eliminate the blood stagnation and stimulate menstrual discharge in uterus, as well as in the cases of lumbago and stomachache due to blood stagnation, blood stasis, mass in the abdomen, and abdominal distention. This combination is also used for the eyes, ears, numbness, and paralysis of hands and feet for the purpose of making the flow of the meridian smooth, and for diabetes, dryness of the skin, malaria, anal itching and pain for the purpose of eliminating the mass and renewing the tissues. The combination is diversly used in the book of ${\ulcorner}$Special lectures on clinical cases${\lrcorner}$ for the aftereffects of traffic accident, constipation, diabetes, dryness of the skin, paralysis of hands and feet, numbness of finger of hand and foot, and especially used frequently with prescription of Yijintang and Samultang combined in the cases of numbness. The prescription is used in Hyungsang medicine when the uterus, the external appearance(axis), hands and feet, heart, and the stomach is not good for the vitalization of the flow of the 12 meridians. It was though difficult to find extinguishing differences between the two herbs in the clinical cases applied in the book of ${\ulcorner}$Special lectures on clinical cases${\lrcorner}$.

• 한국ITS학회 논문지
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• 제6권1호
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• pp.27-37
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• 2007

과속단속시스템은 지능형교통체계(ITS)의 한 영역인 첨단교통관리시스템(ATMS)으로서 중요한 역할을 수행하고 있다. 그러나 과속사고를 방지하기 위해 설치된 시스템이 시거가 확보되지 않은 구간이나 급커브 지역 등에 설치됨으로써 추가적인 교통사고 위험을 내포하고 있다. 이에 본 연구에서는 고속도로의 기하구조별로 시스템 설치위치를 구분하고, 각 위치에서 발생한 교통사고 자료를 시스템 설치 전 후로 나누어 기하구조별 과속단속시스템의 설치 전 후의 사고건수(Frequency), 대물피해환산법(EPDO, Equivalent Property Damage Only)을 통한 사고심각도와 사고비용(Accident Cost)을 분석하였다. 이와 같은 연구수행 절차를 통해 시거가 충분히 확보되지 않는 구간에서의 과속단속시스템의 설치가 사고에 미치는 영향을 알아보고 최종적으로 과속단속시스템의 설치위치에 따른 영향을 분석하고자 한다.

• 대한기계학회논문집B
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• 제26권6호
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• pp.893-901
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• 2002

Effect of boundary layer thickness on the flow characteristics around a rectangular prism has been investigated by using a PIV(Particle Image Velocimetry) technique. Three different boundary layers(thick, medium and thin)were generated in the Atmospheric Boundary Layer Wind Tunnel at Pusan National University. The thick boundary layer having 670 mm thickness was generated by using spires and roughness elements. The medium thickness of boundary layer($\delta$=270 mm) was the natural turbulent boundary layer at the test section floor with fairly long developing length(18 m). The thin boundary layer($\delta$=36.5 mm) was generated on the smooth panel elevated 70cm from the wind tunnel floor. The Reynolds number based on the free stream velocity(3 ㎧) and the height of the model(40 mm) was 7.9$\times$10$^3$. The mean velocity vector fields and turbulent kinetic energy distributions were measured and compared. The effect of boundary layer thickness was clearly observed not only in the length of separation bubble but also in the location of reattachment point. The thinner the boundary layer thickness, the higher the turbulent kinetic energy Peak around the model roofbecame. It is strongly recommended that the height ratio between the model and the approaching boundary layer thickness should be encountered as a major parameter.

• 대한기계학회논문집B
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• 제37권4호
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• pp.377-385
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• 2013

출구유로 단면적이 수직 환상공간 내부의 풀비등 열전달에 미치는 영향을 규명하기 위하여 세 가지 서로 다른 유동제한장치를 실험적으로 연구하였다. 가열 튜브는 매끈한 표면을 가지는 스테인리스강이며 대기압 상태 하에 있는 물을 사용하였다. 환상공간의 하부유로 조건은 개방과 폐쇄된 경우 두 가지를 모두 고려하였으며 유동제한장치를 설치한 환상공간에 대한 결과를 유동제한장치가 없는 환상공간에 대한 결과와 서로 비교하였다. 출구유로 단면적을 축소하는 것은 열전달의 감소를 초래하지만, 출구 유로가 아주 작은 경우 열전달계수가 증가하는 경우도 관찰되었다. 이러한 경향은 기포군집의 형성과 이동에 따른 액체교란의 차이로서 설명되며, 유동대류, 맥동류 발생, 기포 군집 하부의 미세층증발이 중요한 열전달 기구인 것으로 확인하였다.