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스크류반응기를 이용한 흔합플라스틱의 물리적 탈염소에 관한 연구
김상국,엄유진,정수현,Kim Sang-Guk,Eom Yujin,Chung Soo-Hyun 한국자원리싸이클링학회 2006 資源 리싸이클링 Vol.15 No.1
열가소성수지인 PVC는 우수한 물성을 가지고 있어 다양한 용도로 사용되지만 높은 염소함량으로 인하여 폐기할 때 환경문제를 야기한다. PVC로부터의 탈염소반응이 기타 플라스틱 열분해 반응보다 낮은 온도에서 일어나는 점을 이용하여 전처리공정으로의 탈염소반응 연구를 수행하였다. 반응기는 교반능력이 우수한 2축 스크류반응기를 사용하였다. 실험변수는 1차반응기온도, 2차반응기온도, 혼합플라스틱의 PVC농도, 혼합플라스틱 점도, 공급량, 2차반응기의 스크류회전수이다. 적절한 공정조건하에서 탈염소율은 $90\%$ 이상이었으며 탈염소공정에서 배출되는 염소가스를 물에 흡수하여 염산으로 회수가 가능하였다. 염소 물질수지를 취하여 스크류반응기 전후의 염소 흐름을 분석하였다. PVC is the thermoplastic offering excellent material properties. PVC has been used in wide variety of applications, however, it causes environmental problems when it is discarded because of its high chlorine content. Since dechlorination reaction of PVC is taking place at relatively low temperature compared to the pyrolysis temperature of plastics, study on the dechlorination reaction has been carried out as a pre-treatment process. Twin screw reactor which shows excellent mixing capabilities is employed. Experimental variables are the first and second reactor temperature, PVC content in mixed plastics, viscosity of mixed plastics, feeding rate, rotational speed or the second reactor. Over $90\%$ of dechlorination ratio can be obtained under proper operation conditions. Chlorine gas evolved from reactor is absorbed in water and can be recovered as a hydrochloric acid. Analysis had been done on chlorine flows by taking material balance over realtor.
수직진동 rheometer를 이용한 전도유체의 점탄성 연구
김상국,김동찬,최영진,조민성,Kim, Sang-Guk,Kim, Dong-Chan,Choe, Yeong-Jin,Jo, Min-Seong 한국재료학회 1996 한국재료학회지 Vol.6 No.11
본 연구에서는 직접 제작된 전도유체(electrorheological fluid)용 수직진동 rhemeter 기기상의 구조 해석 및 실험을 실시하였다. 수직진동 rheomether는 간단하게 제작이 가능하고, 고전압 발생장치를 연결하므로 전동유체의 점탄성 특성을 비교적 쉽게 측정할 수 있다. Rheometer의 구조적 변수와 측정된 힘, 변형 등을 이용하여 복소 점도(complex viscosity), 복소 전단 변형률(complex shear modulus), loss tangent 등의 선형 점탄성 물질 함수를 직접 계산할 수 있으며, corn starch를 polybutene/kerosene에 분산시킨 전동유체를 이용하여 전기장하의 점탄성을 측정하였다.
분극성을 갖는 미세 입자/유전유체 분산계에서의 전기유변효과
김상국,최윤대,Kim, Sang-Guk,Choe, Yun-Dae 한국재료학회 1993 한국재료학회지 Vol.3 No.2
본 연구에서는 분극성을 갖는 미세분말/유전유체 분산계내의 전기유변효과를 mechanism을 중심으로 고찰하였다. 전기유변효과를 일으키는 mechanism을 (1)입자표면전도(surface conductance) (2)입자내부전도(bulk conductance(3) 유도분극(induced polarization)으로 구분하여 설명하였다. 소수성(anhydrous-base)전기유변유체 내의 미세분말 입자간 상호인력을 예측할 수 있도록 유도분극 mechanism을 적용하여 수학적으로 모델화 함으로써 전기유변효과를 향상 시키기 위한 재료선정의 기초로 하였다. 전기유변유체의 미세입자로 이용될 수 있다고 여겨지는 ceramic, ferrite 및 polymer등 7가지 재료를 선정하여 계산한 결과 ceramic및 ferrite입자가 입자간 상호인력이 큰것으로 나타났다. Abstract Electrorheological effect on the dispersive system of polarizable fine powder/dielectric oil has been investigated. ER effect was explained divided into following 3 mechanisms; (1) surface conductance, (2) bulk conductance, and (3) induced polarization. Mathematical model which predicts the interactive force between two fine particles in the electrorheological fluid has been introduced based on the induced polarization mechanism. This model may provide guide to select materials for strong ER effect. The attractive force between two particles was calculated using the above model for the selected 7 materials such as ceramics, ferrites, polymers etc. From the calculation result, it was found that the ceramics and ferrites are good materials which show a strong ER effect.
3GPP2 $UMB^{TM}$ 기술 개요 및 표준화 현황
김상국,권순일,이병관,Kim, Sang-Guk,Gwon, Sun-Il,Lee, Byeong-Gwan 한국통신학회 2007 정보와 통신 Vol.24 No.12
2007년8월 v2.0을 출간하면서 표준화가 완료된 Ultra Mobile Broadband(UMB) 기술은 진보된 안테나 기술과 함께, CDMA, TDM, Layer-superposed OFDM(LS-OFDM), OFDM, OFDMA의 장점들을 하나의 Air Interface로 통합하였으며, 효율적인 자원 관리 기법을 통해 더 많은 VoIP 사용자들을 수용할 수 있게 해준다. 4x4 안테나를 사용시 20MHz의 주파수 대역에 순방향 288 Mbps, 역방향 75 Mbps의 최대 전송률을 제공하며, 양방향에 대한 평균 Network 지연시간은 약 16.8 ms을 지원하고, 10 MHz 주파수 대역에 1000명 이상의 VoIP 사용자를 지원할 수 있다. 본 고에서는 UMB의 표준화 과정 및 현황 그리고 물리 계층과 MAC 계층의 요소 기술들에 대해 고찰한다.
음식물쓰레기로부터 제조한 분체연료의 연소에 의한 에너지회수 특성
김상국(Kim, Sang-Guk),권효리(Kwon, Hyo-Lee) 한국신재생에너지학회 2009 한국신재생에너지학회 학술대회논문집 Vol.2009 No.11
Food waste contains almost no heavy metals and high fuel ratio 0.14-0.17 that makes it a good candidate for solid fuel. Thermogravimetric analysis showed that volatile matter volatilizes at 200-400?C, and ignition temperature is 460?C. Combustion efficiency measured from energy balance before and after combustion was over 99%. Pulverized fuel made from food waste is a new and renewable energy which contribute to low carbon green economic growth.
천식 환자에서 올바른 정량식 분무흡입기 사용 교육에 대한 효과
김상국(Sang Guk Kim),장안수(An Soo Jang),김윤경(Yun Kyung Kim),이승(Soong Lee),서정평(Jeong Pyeong Seo),양승원(Seung Won Yang),최수인(Soo In Choi),박상후(Sang Hoo Park),이경록(Kyung Rok Lee),박재홍(Jae Hong Park) 대한천식알레르기학회 2000 천식 및 알레르기 Vol.20 No.5
N/A Background: Medications for asthma can be administered either by inhaled or systemic routes. The major advantages of delivering drugs directly into the lungs via inhalation are that higher concentrations can be delivered more effectively to the airways and that systemic side effects are avoided or minimized. Inhaled medications, or aerosols, are available in a variety of devices that differ in required technique and quantity of drugs delivered to the lung. Objective : The purpose of this study was to determine the effects of patient education on correct use of metered dose inhaler in patients with asthma. Methods : Twenty patients with asthma were instructed three times on proper inhaler usage by a physician at two-week intervals. Practical performance and theoretical knowledge were assessed (ten-item assessment). Scoring was done by one physician using a score of 1-3 for each item. Results : The practical performance and theoretical knowledge scores were higher in patients after being instructed three times compared with those who were instructed once (26.2±2.2 vs 18.1±3.6, p< O.01). The scores were higher in patients with higher education level compared with those with lower education level after three lessons (27.3±1.94 vs 24.3±1.80, p< 0.05). The most common errors included inadequate actuation time and breath holding, and insufficient activations. Conclusion : These findings suggest that patients with asthma be instructed in inhaler use and that their technique be checked regularly and repeatedly depending on education level. (J Asthma Allergy Clin 1mmunol 20: 695-701, 2000)
김상국(Sang Guk Kim),장예림(Ye Rim Chang) 한국대기환경학회 2008 한국대기환경학회지 Vol.24 No.2
Toluene adsorption characteristics in the adsorption bed packed with activated carbon fiber (ACF) were studied. Experimental apparatus is composed of VOC generation equipment, adsorption bed, and analytical instrument. Breakthrough characteristics were investigated with length of the adsorption bed which consisted of 3 or 5 sheets of the ACF and flow rate when toluene concentration are 400 ppm and 800 ppm respectively. When mass transfer zone (MTZ) comes out of the adsorption bed, toluene concentration is increased sharply and reached plateau region by saturation. Experimental results are compared with semi-empirical gas adsorption model proposed by Yoon and Nelson. In order to investigate the movement of the MTZ with adsorption time in the adsorption bed packed with ACFs, weight increment of each ACF was measured with the location of ACF at each run. When the weight increment of ACF by toluene adsorption which located at the exit of the bed reaches about 20%, toluene started to be detected.