공비증류에 의한 MEK - 물 - 톨루엔 혼합물로부터 MEK 분리에 관한 이론적 연구

김형규,김성훈,한춘,나병기,정연수,송형근 ( Hyung Kyu Kim,Sung Hoon Kim,Choon Han,Byung Ki Na,Yon Soo Chung,Hyung Keun Song ) 한국화학공학회 1996 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.34 No.2

MEK(methyl ethyl ketone) can be separated from MEK-Water-Toluene azeotropic mixture by azeotropic distillation using the selectivity of entrainer. Acetone was selected as the best entrainer by comparing the ratio between infinite dilute activity-coefficients. Depending on the added amount of acetone and the concentration of MEK-Water-Toluene mixture, the presence of two phase was identified by UNIFAC model. When acetone was added more than 3.14 times the amount of MEK-Water-Toluene mixture, the mixture formed a single phase and the azeotropic point was eliminated. The optimum amount of entrainer to minimize the plate number was calculated through the simulation of distillation process by UNIQUAC equilibrium model. The number of ideal plates increased with MEK composition and was independent of water and toluene composition. Also, the optimum feed-plate location was calculated at each reflux ratio for various amounts of entrainer, and the minimum reflux ratio was identified as 0.6. For the case that brought Acetone-Water as bottom product and MEK-Toluene as distillate from MEK-Water-Toluene mixture where the composition of MEK, water and toluene compositions was 40, 30, 30 mole%, respectively, 14 ideal plates were required for the best results when the reflux ratio was 0.9 and the ratio of entrainer to feed was 5. The bottom product was composed of 56 mole% of MEK and 44 mole% of toluene and the optimum feed-plate was located between the sixth and the eleventh in this case.

Improvement and Verification of the Wear Volume Calculation

김형규,이용호,Kim, Hyung-Kyu,Lee, Young-Ho Korean Tribology Society 2005 KSTLE International Journal Vol.6 No.1

A technique for a wear volume calculation is improved and verified in this research. The wear profile data measured by a surface roughness tester is used. The present technique uses a data flattening, the FFT and the windowing procedure, which is used for a general signal processing. The measured value of an average roughness of an unworn surfnce is used for the baseline of the integration for the volume calculation. The improvements from the previous technique are the procedures of the data flattening and the determination of a baseline. It is found that the flattening procedure efnciently manipulates the raw data when the levels of it are not horizontal, which enables us to calculate the volume reasonably well and readily. By comparing it with the weight loss method by using artificial dents, the present method reveals more volume by aroung 3~10%. It is attributed to the protruded region of the specimen and the inaccuracy and data averaging during the weght loss measurement. From a thorough investigation, it is concluded that the present technique can provide an accurate wear volume.

$37^{\circ}C$에서 incubate 한 가토(家兎) 폐포표면활성물질(肺胞表面活性物質)의 활성도(活性度)의 변화(變化)와 in vitro X 선조사(線照射)의 영향(影響)

김형규,주영은,Kim, Hyung-Kyu,Choo, Young-Eun 대한생리학회 1971 대한생리학회지 Vol.5 No.2

In an attempt to understand the possible effects of temperature and X-irradiation on the activities of surfactant in rabbits, the pulmonary surfactant from the rabbit was subjected to the incubation at $37^{\circ}C$ and X-irradiation with 900r in vitro, and activities of surfactant were measured at 10, 30, 60, and 90 minutes. Tension-area diagram of the lung extract was recorded automatically by the modified Langmuir-wilhelmy balance with a synchronized recording system designed in this Department. A comparison was made with the normal and the following results were obtained. 1) The maximal surface tension, minimal surface tension, width of the tension area diagram at the surface area of 40% and stability index of the normal rabbit lung extract were $31.6{\pm}3.11\;dynes/cm,\;8.2{\pm}0.56\;dynes/cm,\;21.4{\pm}4.40\;dynes/cm\;and\;1.12{\pm}0.22$,respectively. 2) In the $37^{\circ}C$ incubation group, maximal surface tension was similar to the normal value, while minimal surface tension was significantly lower and stability infer was markedly higher than the normal. 3) In the group where X-irradiation of 900r in vitro was applied, maximal surface tension did not differ greatly with the normal or the $37^{\circ}C$ incubation group. The minimal surface tension was significantly lower than the normal but comparing with the $37^{\circ}C$ incubation group, some decrease in minimal surface tension was noted. The width of the tension·area diagram at 40% and stability index in the irradiated group were significantly higher than the normal but a tendency of increase was noted comparing with the $37^{\circ}C$ incubation group.

Development of Wear Model concerning the Depth Behaviour

김형규,이영호,Kim, Hyung-Kyu,Lee, Young-Ho 한국트라이볼로지학회 2005 KSTLE International Journal Vol.6 No.1

Wear model for predicting the vehaviour of a depth is considered in this paper. It is deduced from the energy and volume based wear models such as the Archard equation and the workrate model. A new parameter of the equivalent depth ($D_e$= wear volume /worn area) is considered for the wear model of a depth prediction. A concenpt of a dissipated shear energy density is accommodated for in the suggested models. It is found that $D_e$ can distinguish the worn area shape. A cubic of $D_e$($D_e^3$) gives a better linear regression with the volume than that of the maximmum depth $D_{max}e$($D_{max}^3$) does. Both $D_{max}$ and $D_e$ are used for the presently suggested depth-based wear model. As a result, a wear depth profile can be simulated by a model using $D_{max}$. Wear resistance from the concern of an overall depth can be identified by the wear coefficient of the model using $D_e$.

전방충돌경보(FCW)의 교통안전 증진효과 추정

김형규,이수범,이혜린,홍수정,민혜령,Kim, Hyung-kyu,Lee, Soo-beom,Lee, Hye-rin,Hong, Su-jeong,Min, hye-Ryung 한국ITS학회 2021 한국ITS학회논문지 Vol.20 No.2

자율주행의 핵심기술인 첨단 운전자 지원 시스템(Advanced Driver Assistance Systems) 중 대표기술인 전방충돌경보(Forward Collision Warning)를 대상기술로 선정하여, 주행시뮬레이션 실험 기반의 교통사고 예방효과를 추정하였다. 효과척도로 ①인지반응시간(s) ②감속도(m/s2) ③충돌여부(회)로 선정하여, 전방충돌경보 미설치시와 설치시의 변화량 측정하였다. 실험 시나리오는 운전자 전방의 차량의 급정거하는 시나리오(1)과 옆차로에서 차량이 끼어드는 시나리오(2)를 진행하였으며, 주간/야간으로 구분하였다. 분석결과, 전방충돌경보장치를 설치하였을 경우, 인지반응시간(s)이 감소하였으며, 감속도(m/s2)는 감소하였다. 운전자의 위험상황을 빠르게 감지하여 여유로운 감속을 할 수 있게 되었으며, 그에 따른 전방충돌횟수도 감소한 것으로 분석되었다. 향후 운전자의 운전성향을 반영하고 실험 시나리오를 다양화하면, ADAS의 설치효과를 증대시키고 다른 기술의 효과추정에도 활용될 수 있을 것이다. The Forward Collision Warning, a representative technology of the Advanced Driver Assistance Systems, was selected as the target technology. The cognitive response time, deceleration, and impact were selected as the measures of effectiveness. And the amount of change with and without the Forward Collision Warning was measured. The experimental scenarios included a sudden stop event (1) of the vehicle in front of the driver and an event (2) in which the vehicle intervened in the next lane. All experiments were divided into day and night. As a result of the analysis, response time and the deceleration rate decreased when the forward collision warning system was installed. It was analyzed that the driver's risk situation could be detected quickly and the number of front-end collisions could be reduced as a result. Reflecting the driver's operating habits and diversifying the experimental scenarios will increase the installation effectiveness of ADAS and be used to estimate the effectiveness of other technologies.

MEK - 물 공비 혼합물의 공비증류에 관한 이론적 연구

김형규,이정석,한춘,나병기,정연수,송형근 ( Hyung Kyu Kim,Jung Seok Yi,Choon Han,Byung Ki Na,Yon Soo Chung,Hyung Keun Song ) 한국화학공학회 1995 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.33 No.2

MEK(methyl ethyl ketone) cannot be separated from water by normal distillation because of the presence of minimum boiling azeotrope. However it can be separated by azeotropic distillation by adding entrainer. The best entrainer was selected by considering the ratio between infinite dilute activity coefficients of each component for suggested entrainers and relative volatilities. From this method, acetone was selected as the best entrainer for the MEK-Water system. When the distillation tower was simulated by the UNIFAC equilibrium model for this MEK-Water-Acetone system, the minimum reflux ratio was observed as 0.6. Also, the optimum feed-plate was calculated at each reflux ratio for various amounts of entrainer. Results indicated the number of ideal plates decreases with the amount of entrainer. As the best results, 13 ideal plates were required to obtain 95 mole% of MEK as the bottom product from 70 mole% of MEK of the MEK-Water solution when the reflux ratio and the ratio of entrainer to feed were 0.85 and 2, respectively. In this case, the optimum feed-plate location, which required the minimum number of ideal plates, was the eighth.

DEA를 이용한 교통사고 잦은 곳 개선사업 효율성 측정방안 연구

김형규,이수범,엄대룡,원동욱,신소명,Kim, Hyung Kyu,Lee, Soo Beom,Eom, Dae Lyoung,Won, Dong Uk,Shin, So Myoung 한국안전학회 2017 한국안전학회지 Vol.32 No.5

Over the past 30 years, the business effects of the improvement project at black spot have been decreasing since 2010, with a reduction in the amount of government spending, coupled with proposing a uniform improvement plan. In order to promote more efficient improvement projects, it is necessary to evaluate the efficiency of local governments and improve the business methods of local governments with low efficiency. However, more sophisticated efficiency analysis methods are needed. Because in previous studies have been limited to the analysis of effects before and after the project through the simple before-after analysis. For this purpose, this study analyzed the efficiency of improvement project at black spot by local governments in Gyeonggi-do using DEA to compare and analyze efficiency in various fields. As a result, Goyang, Seongnam, Paju, Hanam and Yangju showed high efficiency local governments. For local governmetns with low efficiency, the improvement projets to improve efficiency were divided into civil engineering work, structure work, pavement work, additional work and transportation work, and the appropriate construction ratios of each local government were analyzed and presented.

응착조건의 완전접촉문제 해석

김형규(Hyung-Kyu Kim),장재원(Jae-Won Jang),이순복(Soon-Bok Lee) 대한기계학회 2015 大韓機械學會論文集A Vol.39 No.6

완전접촉 문제를 이론적으로 해석하기 위해서 점근해법이 많이 사용된다. 점근해로서의 응력장은 특이항 만으로 구성되므로 접촉경계로부터 멀어질수록 정확도가 감소한다. 이에 반해 유한요소해석 방법은 요소크기의 제한으로 인해 완전접촉 문제에서의 응력특이성을 엄밀히 표현할 수 없다. 따라서 본 연구에서는 이론적 해법을 보조하고 또 그와 비교하기 위해 응착접촉 상태에 있는 완전접촉 문제를 이론적으로 해석한 후, 모아레 실험 및 유한요소해석 방법으로 접촉부 부근의 응력장을 분석하였다. 실험은 알루미늄과 구리 합금을 접촉각 120°, 135° 로 가공하여 수행하였으며 모아레 무늬로부터 얻은 변위장과 유한요소해석을 수행한 결과와 비교하였다. 이로부터 타당성이 확보된 수치적 방법을 이용하여 실험조건에서의 일반화 응력확대계수와 접촉부 응력장을 구하여 이론 해와 비교하였으며, 접촉경계로부터 멀어질 때 나타나는 이론과 수치 해의 차이를 분석하였다. Asymptotic method has been often used to theoretically analyze the complete contact problem. The error of the asymptotic results increases as the distance from the contact edge increases. The singularity cannot be properly obtained from a finite element (FE) analysis owing to the finiteness of the element size. In the present work, the complete contact problem in bonded condition is analyzed using a combined experimental-numerical approach to assist and/or compare with the asymptotic results. Al and Cu alloys are used for the material combination of the punch and substrate. 120 and 135 degrees are used for the punch angle. The FE models are validated by comparison of displacement distributions obtained by the FE analysis and moire experiment. Generalized stress intensity factors are evaluated using the validated FE models. Stress field in the vicinity of the sharp contact edges obtained from the FE and asymptotic analyses are compared. The discrepancies are also discussed.

쐐기접촉의 프레팅피로균열 응력확대계수 계산의 문제점 고찰

김형규(Hyung-Kyu Kim) 대한기계학회 2024 대한기계학회 춘추학술대회 Vol.2024 No.6

완전 및 불완전 접촉 하의 프레팅피로 균열성장거동 비교해석

김형규(Hyung-Kyu Kim) 한국트라이볼로지학회 2024 한국트라이볼로지학회 학술대회 Vol.2024 No.4