Ca 첨가한 AZ91 마그네슘 합금 용탕의 산화거동

최병호,유봉선,박원욱,박익민 대한금속재료학회 2004 대한금속·재료학회지 Vol.42 No.8

The effects of Ca addition on the liquid oxidation behaviors of AZ91 alloys have been investigated. The oxide layers formed on the molten Ca-containing AZ91 alloys were investigated by using scanning electron microscope and Auger electron spectroscopy in order to elucidate the effect of Ca additions on the ignition and burning of the molten alloys. The thermogravimetric measurements indicated that Ca-containing AZ91 alloys have good oxidation resistance. AES depth analysis revealed that the oxide layers on the molten Ca-containing AZ91 alloys consisted of several layers; the outer layer mainly consisted of CaO and the inner layer was mainly a mixture of CaO-MgO and Al₂O₃. The formation of protective CaO in the oxide layer was directly responsible for improved oxidation resistance of the Ca-containing AZ91 alloys.

사후분해 시체에 대한 법의학적 접근

최영식,이상용,김유훈,조갑래,이봉우,양경무,정낙은,서중석,이한영,이원태,강현욱 大韓法醫學會 2000 대한법의학회지 Vol.24 No.2

Disposal of a homicide victim by dismemberment is rare, but individual cases are on record in most major medicolegal departments. Recognition of postmortem mutilation may be of importance in the interpretation of certain murders committed by sexual perverts and other mentally deranged individuals and sometimes performed for the sole reason of easier disposal of the body. Postmortem dismemberment is usually readily recognizable as such; The edges of the injuries are dry and lack evidence of bleeding. The joints may be disarticulated without fracture, or the use of an axe or saw may be evident from examination of bones. Parallel horizontal or oblique furrows in the bone surface are caused by skipping of the saw prior to establishing depth. Such patterns on the bone may assist in identifying the particular saw involved. So we report 25 dismembered corpses that autopsied in National Institute of Scientific Investigation. This paper can help in attempting to establish not only the first criminal investigation steps but also the medicolegal approach methods in unidentified and dismembered deaths.

도시내 타워건축에 따른 경관영향 분석방안에 관한 연구

최봉문,김진욱,김부흥 牧園大學校 建築·都市硏究센터 1999 建築·都市環境硏究 Vol.7 No.-

Tower architectures affect their city-scape by their size, shape and height among other buildings and natural elements. Therefore the tower become the landmark of the town and symbolic and cognition element of the city scape. In this thesis we suggest a way to analyze the influence of tower construction to the city scape and we explain the concept and processes of visibility analysis, the analysis of view point and analysis of aerial view as the way of study of the city scape. Finally we propose the evaluation methods for the city tower to establish evaluation indices and elements following characteristics of the tower.

RAMPANT를 이용한 충돌모델주위에 유동에 관한 연구

李鳳來,崔成旭 홍익대학교 산업기술연구소 1997 産業技術 Vol.7 No.-

Conventional aerodynamic simulations have been carried out by using Supercomputer and over a hundred thousand grid points. It takes a long CPU time to get a result. So this method has been mainly used as a research and demonstration tool. In this paper a practical aerodynamic simulation for early phases of the automobile design is presented. CFD(Computational Fluid Dynamics) has been able to apply to industrial field in these days. CPU time is shortened and more fine-mesh can be calculated. This new method has been applied to the aerodynamic simulation system a designer has been able to carry out the practical simulation on early designing phase of an automobile.

Sol-gel 공정에 의한 Silica sol의 합성 및 특성

이봉우,최용욱,우기석,박문수,김선일 조선대학교 생산기술연구소 1998 生産技術硏究 Vol.20 No.1

Reaction completion time was investigated to measure OH/CH ratio as reaction time at 25℃. In 50 and 60 minute reaction was completed in 1.0 ratio that was reached equilibrium state. In another method, equilibrium, state was investigated by measuring volume% of C₂H_(5)OH. From 40 to 50 minute. that was reached at 61.6 of volume% After reaction. monomer and tetrasilicate(92%) as main product was discovered and so oligomer(6%). Mean molecular weight (Mw) of sol solution was about 7.000. The beginning point and ending point of hardening was measured through the TGA investigation of reaction material. The hardening of sol solution was complected in 7 minute and viscosity was maximum from 4 to 5 minute and was set at 9 minute.

공기역학적 항력특성에 대한 실험적 연구

李鳳來,崔成旭 홍익대학교 산업기술연구소 1998 産業技術 Vol.8 No.-

We install various model in test section of wind tunnel. With constant velocity, we give each variable distance and then take data from pressure holl by using Micro-Manometer and observe pressure difference of body's surface and see real-body flowtype by using smogwrite method with scanning point based on flow type's size. We connect pitot tube with travers. We see pressure difference of surrounding body moving travers up-down and see flow property accoding to pressure difference by using data here

운동 강도의 차이가 흰쥐의 혈액 성분과 적혈구의 형태에 미치는 영향

김부환,김종오,지용석,최대원,윤진환,정일규,김영욱,오봉석 한국스포츠리서치 2004 한국 스포츠 리서치 Vol.15 No.4

This study was to investigate the effects on hematological indices and heinz body formation in various intensity, Male Sprague-Dawley rats were randomly divided into the control group, the low-intensity exercise group, nigh-intensity exercise group (n=7 in each group). Animals of the low-intensity exercise groups were put on exercise 30 min per 1 day, 5 days per week for 6-weeks. Animals of the high-intensity exercise groups were put on exercise 120 min per 1 day, 5 days per week for 6-weeks. Red blood cell count (RBC), hemoglobin (Hgb), hematocrit (Hct), mean ceil volume (MCV), mean hemoglobin corpuscular (MCH), mean hemoglobin corpuscular concentration (MCHC) were analyzed in automated hematology analyzer (ABX Hematology MICROS 60) from 10㎕ of whole blood. Erythrocyte morphology were evaluated in super vital (Brilliant cresyl blue stain) stained blood films. In the present results, Hg, MCHC in the high-intensity exercise group was significantly decreased compared with the different exercise intensity and the control group. MCV in the high-intensity exercise group was significantly increased compared with the different exercise intensity end the control group. Heinz body formation in the high-intensity exercise group was significantly increased compared with the different exercise intensity and the control group. In the present study, it can be suggested that intensity of exercise can influence hematological variables and heinz body formation. These findings suggest that high intensity exercise induces oxidative damage to erythrocyte.

쪽거리 차원을 통한 다공질규소의 미세구조 분석

김영유,홍사용,이춘우,류지욱,이기환,최봉수 대전산업대학교 반도체기술연구소 1999 半導體技術硏究所報 Vol.1 No.-

p형 단결정 규소 웨이퍼를 불화수소 용액속에서 전류밀도와 양극반응 시간을 변화시켜 다공질규소를 제작하고, 그 질량을 측정한 후 이 값으로부터 다공도와 쪽거리(fractal)차원을 계산하였다. 그 결과 양극반응 시간이 일정한 경우 다공도는 전류밀도에 비례하였다. 그리고 전류밀도가 일정한 경우 여러 양극반응 시간의 데이터로부터 얻은 쪽거리 차원은 일정하였다. 또한 쪽거리 차원은 불화수소의 농도 증가에 따라 감소하였다. 이같은 실험 결과를 퍼짐한계침전(diffusion limited deposition) 모형으로 계산된 2차원 컴퓨터 시늉내기(simulation) 결과와 비교 분석하였다. 시늉내기 결과 다공도는 퍼짐거리에 비례하였으며, 쪽거리 차원은 퍼짐거리와 반비례하였다. 이때 퍼짐거리는 전류밀도에 비례하고 불화수소의 농도에 반비례하는 물리량이므로 정성적으로 실험 결과와 일치하였다. 그러나 쪽거리 차원이 증가함에 따라 다공도가 감소되는 결과는 실험결과와 상반되었다. Porous silicon layers were fabricated with various conditions of HF concentration and current density. And their masses were measured. From these data, the porosity and fractal dimension were estimated and analyzed. We found that the porosity was proportional to the current density when the anodic reaction time was fixed and the constant values of fractal dimension could be estimated from a series of data with fixed HF concentration. The values of fractal dimension were decreased with increasing HF concentration. The obtained porosity and fractal dimension were compared with the 2-dimensional computer simulation based on diffusion limited deposition model. According to the simulation, the porosity was proportional to the diffusion length and the fractal dimension was inversely proportional to the diffusion length. Since, the diffusion length is proportional to current density and inversely proportional to base concentration, our experimental data qualitatively agreed with the results from the simulation. The porosity obtained by experiments, however, was not consistent with the results by simulation.

수출입 컨테이너 장치장 배정을 위한 소프트웨어의 개발

김갑환,김홍배,홍봉희,김기영,배종욱,최진오,김두열,이영기,박영만,박강태,손행대 한국경영과학회 1995 經營 科學 Vol.12 No.3

The Pusan Container Terminal faces a rapid increase in berthing time of container ships as well as in waiting time of external trucks, which is due to an absolute lack of yard space. This research is focused on the development of a decision support system for the planning of the container terminal yard assignment so that the yard space would be utilized most effectively. Efforts should be given to the reasonable assignment of the yard storage and the dynamic adaptation to the ever changing environment. The software introduced here is based o the know-how of the field exports and its framework takes the approach of the hierarchical decision making.

3D Macroporous Graphene Frameworks for Supercapacitors with High Energy and Power Densities

Choi, Bong Gill,Yang, MinHo,Hong, Won Hi,Choi, Jang Wook,Huh, Yun Suk American Chemical Society 2012 ACS NANO Vol.6 No.5

<P>In order to develop energy storage devices with high power and energy densities, electrodes should hold well-defined pathways for efficient ionic and electronic transport. Herein, we demonstrate high-performance supercapacitors by building a three-dimensional (3D) macroporous structure that consists of chemically modified graphene (CMG). These 3D macroporous electrodes, namely, embossed-CMG (e-CMG) films, were fabricated by using polystyrene colloidal particles as a sacrificial template. Furthermore, for further capacitance boost, a thin layer of MnO<SUB>2</SUB> was additionally deposited onto e-CMG. The porous graphene structure with a large surface area facilitates fast ionic transport within the electrode while preserving decent electronic conductivity and thus endows MnO<SUB>2</SUB>/e-CMG composite electrodes with excellent electrochemical properties such as a specific capacitance of 389 F/g at 1 A/g and 97.7% capacitance retention upon a current increase to 35 A/g. Moreover, when the MnO<SUB>2</SUB>/e-CMG composite electrode was asymmetrically assembled with an e-CMG electrode, the assembled full cell shows remarkable cell performance: energy density of 44 Wh/kg, power density of 25 kW/kg, and excellent cycle life.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2012/ancac3.2012.6.issue-5/nn3003345/production/images/medium/nn-2012-003345_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn3003345'>ACS Electronic Supporting Info</A></P>