에멀젼型 液膜에 對한 數式모델 比較硏究

宋東益,崔相俊 慶北大學校 1983 論文集 Vol.36 No.-

Two diffusion-controlled mathematical models for emulsion-type liquid membrane, which were proposed by Lightfoot and Ho, and Ihm and Choi, were simulated by solving numerically the coupled moving boundary value problem using Crank-Nicholson implicit method and were compared with the batch experimental data obtained previously for removal of phenol from waste water. The results have shown that Lightfoot and Ho's model which was based on uniform mass transfer resistance inside the emulsion globules was not in good agreement with the experimental data especially at initial time period, but Ihm and Choi's model considering mass transfer resistances in the outer liquid membrane layer and in the inner reacted zone simulataneously, was fitted well the experimental data for nearly entire time period. Therefor, Ihm and Choi's model taking into consideration the outer mass transfer resistance layer of liquid membrane was thought to be more predictive and more precise than Lightfoot and Ho's one in the emulsion-type liquid membrane.

液膜法에 依한 Cu(Ⅱ) 이온의 抽出에 關한 硏究

崔相俊,宋東益 慶北大學校 1984 論文集 Vol.37 No.-

Water in oil (W/O) emulsion was prepared from aqueous hydrochloric acid solution and xylene containing both benzoyl acetone as a carrier and Span 80 as a surfactant. After dispersing W/O emulsion into a third aqueous phase, external buffer solution dissolving copper ion, water in oil in water (W/O/W) emulsion was manufactured. Copper ion extraction was performed using this W/O/W emulsion system. Effects of characteristic of external aqueous solution on emulsion stability were investigated and optimum extraction conditions were determined using the results of extraction experiment. Optimum conditions were as follows; surfactant concentration was 2wt. %, internal aqueous hydrochloric acid concentration 0.3M, carrier concentration 0.02M, stirring speed 200 rpm, pH of external aqueous buffer solution 5.5 and volume ratio of external aqueous buffer solution to emulsion phase 6. When initial copper concentration of external aqueous buffer solution was 500 ppm, copper ion could be removed to 99% from external solution in 30 min.

고양이 위 평활근 수축에 대한 Vanadate와 Pervanadate의 효과

심상수,최효봉,심혜선,이덕주,윤신희,한상준,김명석,조양혁 大韓消化器病學會 1999 大韓消化器病學會誌 Vol.33 No.1

하청 근로자들의 건강수준 평가

최홍열,고상백,장세진,차봉석,임형준,이상윤,김재용,강동묵,조수헌 大韓産業醫學會 2001 대한직업환경의학회지 Vol.13 No.1

목 적 : 하청노동을 이용한 노동 유연화 전략은 근로자들의 고용을 불안정시키고, 근로자들의 삶에 부정적 영향을 미치고 있다. 따라서 이 연구는 하청업체 근로자들의 고용현황을 조사하고, 기존의 업체중심의 건강평가의 문제점을 지적하고자 하였다. 또한 하청업체 근로자들의 건강평가의 현재적 의미와 사회적 배제의 특성을 알아보고자 하였다. 방 법 : 모기업과 하청업체 근로자들의 건강수준을 비교하기 위하여, 정기건강진단(일반, 특수)과 채용건강진단 자료를 이용하고자 하였다. 건강진단에서 누락된 비정규직을 포괄하기 위하여 SF-36을 이용하여 건강설문조사를 시행하였다.결 과 : 조선업 하청업체 근로자들의 고용기간은 짧고, 빈번한 노동이동 현상을 보였다. 3년간 건강진단 수검 현황을 통해 살펴볼 때, 1998년 수검자중 2000년까지 연속해서 검진 받은 수검자는 40.3%였다. 건강진단 결과 유소견자 규모를 통해 모기업과 하청업체간의 건강수준을 비교해 보았다. 모기업은 일반질병 요관찰자와 질병자를 포함한 유소견자가 1,011명으로 약 10 %의 유소견율을 보이고 있고, 질병자의 경우 596명으로 유병률이 5 %를 상회하고 있다. 반면 하청업체의 경우 1,967명의 수검자중 유소견자가 115명으로 6 %의 유소견율을 보이고있고, 질병자는 82명으로 4 %의 유병률을 보이고있다 채용건강진단을 받은 수검자는 6,260명 이었으며, 이 중 유소견자 수는 2,373명으로 전체 수검자의 37.9 %를 차지하였다. 건강설문지의 경우는 전체 건강수준의 총합은 하청보다 원청 근로자가 높았고 통계적으로 유의하였다. 결 론' 정기건강검진 결과는 하청근로자들이 고용형태에 따라 검진을 받지 못한 경우가 많아, 건강 근로자 효과로 표현될 가능성이 있다. 따라서 채용건강진단 결과는 다른 측면에서 하청업체 근로자들의 건강수준의 현실적 반영이라고 할 수 있다. 향후 하청업체 근로자들의 건강문제를 감시하고 개선하려면 기존의 업체 중심의 접근으로는 하청 근로자의 건강문제를 제대로 다룰 수 없고, 업종과 지역을 동시에 고려하여 접근할 필요가 있다. 또한 단기 고용 근로자 및 비정규직 근로자를 사회보장의 확충과 모기업의 연대책임 강화 및 기업복지 차원에서 포괄하는 방안이 모색되어야 하겠다. Objectives : The strategy for the labor flexibility through subcontracted labor have brought a negative effect on the lives of the workers, such as the increase of the unstable employment. This study was conducted to analyze the relationship between the employment of subcontracted firms and the health status of them, and to find out some problems which have been caused in the process of health evaluation and the characteristics of social exclusion. Methods : We reviewed the periodical health examination and preemployment health examination in order to compare health status of the subcontracted workers with those of the parent firm workers. The SF-36 questionnaire was administered to assess the self-perceived health status. Results : The result shows that compared to the working duration of the parent firm workers, those of the subcontracted workers were shorter, and the job transfer rate was higher. In the periodical health examination, the prevalence of occupational and general disease was higher in the parent firm(10%) than in the subcontracted firms(6%). Preemployment health examination plays an important role in worker's health manage- ment. Among 6,260 workers who received preemployment health examination, the prevalence of disease was 37.9%. Mean scores of health status measured by SF-36 were lower in the subcontracted firm than in the parent firm. Conclusions : Due to social exclusion of the subcontracted workers from the periodical health examination, there is a possibility that the periodical health examination have the healthy worker effect. These results suggests that the preemployment health examination could be a more appropriate indicator which is able to assess the health status of the subcontracted workers than the periodical health examination.

Mori 체계의 이해

崔尙惇,金泰縣,安琮準,李相錫,崔昌鎬 경북대학교 과학교육연구소 1989 科學敎育硏究誌 Vol.13 No.-

Heuristic understanding of Mori's problem is introduced

무증상의 후두개곡 낭종 환자에서 예기치 못한 어려운 기관내 삽관 1례

이상모,최준석,이철승,김원태,박천희 朝鮮大學校 附設 醫學硏究所 2007 The Medical Journal of Chosun University Vol.32 No.1

Although vallecular cyst is often asymptomatic and harmless to the patient, discovery of large vallecular cyst after induction of anesthesia is a potentially life-threatening problem for thepatient and provides for the anesthesiologist a challenge in airway management. We describe a case of difficult intubation where the laryngeal inlet was obscured by a large vallecular cyst that was discovered during induction of general anesthesia. A 47-year-old man presented for elective laparoscopic colecystectomy due to GB polyp. He had normal mouth opening and neck extension; no mass or distortions of the tongue or neck were observed. Anesthesia and paralysis were induced with 80 ㎎ propofol, alfentanil 0.5 ㎎, midazolam 2.0 ㎎ and rocuromum 50 ㎎. It was noted that ventilation of the lungs via mask was difficult. Despite insertion of an oropharyngeal airway, ventilation proved to be more difficult. Intubation was attempted. Direct laryngoscopy (Macintosh 3 blade) revealed a 3-4 ㎝ tranlucent cyst arising from the left vallecula. The cyst completely obscured the view of epiglottis and vocal cords, preventing intubation despite multiple attempts by three anesthesiologists. StafF anesthesiologist was aspirated cyst using a 16-guage needle, syringe and 20 ㎖ of serous fluid were aspirated from cyst. The epiglottis and vocal cord were then exposed and tracheal intubation was performed easily with a size 7.0 cuffed oral tracheal tube. Anesthesia and the operation then proceeded uneventfully, following laparoscopic colecystectomy, an ENT surgeon removed the cyst.

초정밀 광소자 정렬 스테이지의 구동 특성에 관한 연구

정상화,차경래,김현욱,최석봉,김광호,박준호 한국공작기계학회 2005 한국공작기계학회 춘계학술대회논문집 Vol.2005 No.-

As the optical communication is introduced to the backbone network at first and becomes a general communication method of network, the demand of kernel parts of optical communication such as PLC(Planar Light Circuit), Coupler, and WDM(Wavelength Division Multiplexing) element increases. The alignment and the attachment technology are very important in the fabrication of optical elements. In this paper, the driving mechanism of ultra precision stage is studied with the aim of optimal design of stage. The travel and the resolution of stage are investigated. The hysteresis of the stage is generated because of PZT actuator. The hysteresis and the inverse hysteresis are modeled in X, Y, and Z-axis motion. The input data of desired displacement to the stage according to input voltage is obtained from the inverse hysteresis equation. In the result of experiments with the input data, the errors due to hysteresis are well compensated.

고상 에피텍시 성장을 이용한 elevated source/drain 공정연구

金湘薰,崔在植,崔圭鎭,金亨駿 弘益大學校 科學基術硏究所 1999 科學技術硏究論文集 Vol.10 No.2

Recently, semiconductor devices require the ultrashallow junctions and low leakage current. Self-implantation to make preamorphization prevents channeling and minimizes junction depth. But in this way, implantation with high energy makes defects like dislocation loop in depletion region and interface between amorphous silicon and silicon wafer. But solid phase epitaxy using low pressure chemical vapor deposition prevents channeling, allows the easy control of junction depth by amorphous layer thickness, and improves the conventional processes. Amorphous silicon films in source and drain by LPCVD are elevated from the Si substrate. This structure is called "elevated source/drain". The elevated source/drain process improves metal contact and simplify the fabrication process. Usually, the amorphously-deposited Si films by chemical vapor deposition are crystallized to polycrystalline films due to a formation of SiO₂layer at the amorphous Si/Si substrates interfaces. Formation of SiO₂layer on Si surface can be effectively prevented by flowing the Si₂H?? gas during the heating-up procedure for amorphous Si depositions. In this way, amorphously deposited Si layer onto (100) Si substrates was grown epitaxially during the post-deposition heat treatments. The suppression of surface SiO₂can be explained in terms of adsorption of SiHx adspecies, instead of oxygen from residual gases in the reactors, to Si surfaces after desorption of hydrogen from H-passivated Si surfaces. Employing Si₂H?? flowing and solid phase epitaxial growth, high-quality epitaxial Si layer was obtained at low temperatures below 500℃ without conventional high temperature cleaning procedures. Amorphous Si films on Si substrate are epitaxially grown and amorphous Si films on SiO₂layer remain as amorphous with proper heat treatments. Uncrystallized amorphous Si films on SiO₂layer can be selectively etched using the HNO₃/HF/HNO₃/CH₃COOH solution with proper mixing ratio and elevated source/drain regions were formed.

극초정밀 다축 스테이지의 광소자 정렬에 관한 연구

정상화,차경래,김현욱,최석봉,김광호,박준호 한국공작기계학회 2005 한국공작기계학회 춘계학술대회논문집 Vol.2005 No.-

In recent years, as the demands of VBNS and VDSL increase, the development of kernel parts of optical communication such as PLC(Planar Light Circuit), Coupler, and WDM elements increases. The alignment and the attachment technology are very important in the fabrication of optical elements. In this paper, the optical alignment characteristics of multi-axis ultra precision stage were studied. The alignment algorithms were studied for applying to the ultra precision multi-axis stage. The alignment algorithm is comprised of field search and peak search algorithms. The contour of optical power signals can be obtained by field search and the precise coordinate can be found out by peak search. Two kinds of alignments, such as 1ch. input vs. 1ch. output optical stack, and 1ch. input vs. 8ch. output PLC stacks were performed for investigating the alignment characteristics.

구간분할 바이너리 제어를 이용한 로봇핸드의 동특성에 관한 연구

정상화,차경래,김현욱,최석봉,김광호,박준호 한국공작기계학회 2005 한국공작기계학회 춘계학술대회논문집 Vol.2005 No.-

In recent years, as the robot technology is developed the researches on the artificial muscle actuator that enable robot to move dextrously like biological organ become active. The widely used materials for artificial muscle are the shape memory alloy and the electro active polymer. These actuators have the higher energy density than the electromechanical actuator such as motor. However, there are some drawbacks for actuator. SMA has the hysterical dynamic characteristics. In this paper the segmented binary control for reducing the hysteresis of SMA is proposed and the simulation of anthropomorphic robotic hand is performed using ADAMS.