응집공정에 적합한 In-Line 정적혼화기를 이용한 혼화공정의 개선

정철우,강민수,최시환,정수일,손인식,강임석 대한상하수도학회 2003 상하수도학회지 Vol.17 No.3

The rapid mixing process for coagulation is a critical component in a water treatment plant. However, at the present time a detailed understanding of the rapid mixing by in-line mixer or generally accepted criteria for the design of in-line static mixer are not available. The aim of this work is therefore to improve the understanding of how the in-line static mixer works and how to better utilize it in coagulation process in water treatment. To investigate the performance of static mixer, coagulation experiments were conducted to compare the static mixer to the traditional backmixer under several coagulation conditions. Experiments were also performed to compare the coagulation efficiency of different mixing type of static mixer which were made using different flow rates and the number of elements equipped in a pipe. The static mixer performed better than the backmixer for all coagulation and mixing conditions tested. Especially, the static mixer was very effective in the surface charge neutralization, as showing higher reduction of negative charge with increasing mixing intensity. However, little difference was observed in the performance of the static mixer equipped with 2, 3, and 5 elements. Also, in a series of bench-scale studies of rapid mixing, the in-line static mixer performed better than the traditional backmixer for both adsorption and charge neutralization (A/N) mechanism and sweep coagulation mechanisms. Especially, the static mixer was more efficient at producing A/N mechanism conditions as a result of its fast and uniform dispersion of the coagulant.

냉기 치료에 따른 둔근에서의 피부 및 근육내 온도 변화

정우성,김미정,박시복,이상건,김영호,양길태,장윤희 大韓再活醫學會 1998 Annals of Rehabilitation Medicine Vol.22 No.2

청소년 정신과 환자 중 외톨이 혹은 왕따 특성을 보이는 환자에 대한 예비 연구

손정우,김은정,홍성도,이시형,홍강의 대한소아청소년정신의학회 2000 소아청소년정신의학 Vol.11 No.2

본 연구는 청소년 정신과 환자 중 외톨이 혹은 왕따 특성을 보이는 환자에 대한 예비연구이다. 청소년 정신과 환자 25명에게 외톨이 설문지, 왕따 설문지 등 8개 설문지를 시행하였고, 일반적인 친구 관계를 질문하였다. 외톨이 설문지 및 왕따 설문지의 점수를 근거로 15명의 외톨이-왕따 집단과 10명의 비외톨이 집단으로 나눈 뒤 일반적 친구 관계와 8개 설문지의 점수를 비교하였다. 또한 5명의 외톨이-왕따 환자 사례를 분석하였다. 이때 SCL-90-R의 우울 차원 점수, 불안 차원 점수, 편집 차원 점수, SCL-90-R의 4가지 차원의 총합, 사회 불안 설문지 점수 등에서 두 집단이 유의한 차이를 보였다. 5명의 외톨이-왕따 환자의 사례 분석 결과, 병원을 찾은 청소년 정신과 환자는 언어 발달 및 인지 발달의 지연 등 발달에서의 문제가 동반되는 경우에 외톨이-왕따를 당할 가능성이 높은 경향을 보인다. 중심 단어 : 외톨이ㆍ왕따ㆍ청소년ㆍ발달. This study was a preliminary study on the adolescent psychiatric patients that show the characteristics of peer group neglect or rejection. We divided the adolescent psychiatric patients (n=25) into neglect-reject group(n=15) and non-neglect group(n= 10). Each patient answered 8 scales and several questions about general relationships with friends. And, both the score of each 8 scales and answer about qusetions were examined. Lastly, records of 5 cases from neglect-reject group were analyzed. The depression dimension score of SCL-90-R, anxiety dimension score of SCL-90-R, paranoid dimension score of SCL-90-R, interaction anxiousness scale(IAS) score were significantly different between 2 groups. On the result of case analysis about 5 patients of neglect-reject group, the adolescent psychiatric patients had a tendency to be rejected or neglected in case of having developmental problems(for example, language development or cognitive impairment). KEY WORDS : Peer neglectㆍPeer rejectionㆍAdolescentㆍDevelopment.

전산의 사용에 따른 업무능률성 분석 : 경상북도 구미시청의 사례 The Case of Gu Mi City Hall, Kyong Sang Book Do

김시영,정우열 영남대학교 지역발전연구소 1998 새마을지역개발연구 Vol.23 No.-

Nowadays, the Local government have become extensive users of computing. The increase in computing use has been based on the assumption is a tool which enables agencies to increase their business efficiency. According to the analysis of the data collected from the Gu-Mi city local government, analysis in efficiency attributable to the use of computing are perceived by local government employees in term of work speed, accuracy, cost saving, service improvement, and sense of accomplishment. However, much uncertainty exists regarding the utilization of time freed, coordination of service delivery by the use of computing.

음전하를 띤 Microsphere 에 의한 정전기적 반발력이 정밀여과에서 투과 플럭스에 미치는 영향 고찰

박정민,최성욱,방시원,함승주,김중현,김우식 한국화학공학회 2001 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.39 No.6

본 연구에서는 일정 압력하에서 음전하를 띤 microspheres의 정전기적 반발력에 따른 투과 플럭스의 변화에 관하여 고찰하였다. Microsphere의 정전기적 반발력에 관한 영향을 관찰하기 위해 표면전하 밀도(N_c: 0.45, 5.94, 10.25)가 각각 다른 poly(Styrene/Methacrylic acid) microspheres를 제조하였다. 교반속도는 300, 400, 600 rpm, 이온강도는 0.1, 0.01, 0.001로 변화시켜 실험하였다. 투과 플럭스는 표면전하밀도, 교반속도, 이온강도에 큰 영향을 받음을 알 수 있었으며, 투과 플럭스는 표면전하밀도가 클수록, 교반속도가 증가할수록, 이온강도가 작을수록 증가함을 알 수 있었다. 교반속도가 크면 막표면의 농도분극층의 두께가 얇아지기 때문에 투과 플럭스는 증가한다. 이온강도가 작을수록, 표면전하밀도(surface charge density)가 클수록 투과 플럭스가 커지는 원인은 microspheres의 정전기적 이중 층의 두께가 두꺼워짐에 따라 입자 사이의 거리가 멀어져 공극률(porosity)이 커지기 때문이다. 정상상태 플럭스 자료로부터 비 저항 정의식을 이용하여 케이크층의 공극률을 구할 수 있었다. 전하를 나타내지 않는 polystyrene microspheres의 입자크기가 480㎚일 때 농도분극 층의 이론적인 공극률은 0.211이었고, microspheres의 표면이 methacrylic acid로 완전히 개질된 것은 비 저항정의식에 의해 3.04로 계산되었다. 또한 microspheres들간의 정전기적 상호작용력이 작아지면 농도분극층의 공극률도 줄어드는 것을 알 수 있었다. The effect of the surface charge density(N_c: 0.45, 5.94, 9.14 and 10.25) and the stirrer speed(300, 400 and 600 rpm) on the variation of permeate flux was investigated in a stirred cell filled with negatively charged microspheres under constant pressure. It was found that the permeate flux depended on the surface charge density, the ionic strength and the stirrer speed. High permeate flux was obtained in the condition of high surface charge density, low ionic strength and high stirrer speed due to the force of electrostatic interaction between microspheres. The porosity of a cake layer was calculated from the steady-state flux data. It was found that the reduction of porosity was due to a decrease in repulsive interaction between microspheres.

한국 전통 도깨비 문양을 고려한 팬던트 생산용 금형 제작 및 상품화 방안 연구

원시태,강민아,최우정,강미로 서울産業大學校 2005 논문집 Vol.54 No.1

Korean traditional ogre patterns generally have a meaning of protecting from demons and charming away unfortunates. However, their threatening faces and complexity of shapes have not appealed to the general public as personal accessories. In order to make use of their aesthetic and peculiar beauty of figures, a new concept of ogre accessory having a friendly-butterfly shape pendant is develope This study demonstrates whole processes of a capstone design case study, that is, conceptualization of the butterfly ogre pattern, die design and manufacturing for mass production, real production and quality progress, and commercialization process.

Inclusions Nucleating Intragranular Polygonal Ferrite and Acicular Ferrite in Low Alloyed Carbon Manganese Steel Welds

박경태,Si Woo Hwang,Jung Hoon Ji,이창희 대한금속·재료학회 2011 METALS AND MATERIALS International Vol.17 No.2

The inclusion-assisted formation of two types of intragranular ferrite in low alloyed C-Mn steel welds, intragranular polygonal ferrite (IPF) and acicular ferrite (IAF), was investigated in relation to the inclusion characteristics (mainly size and chemistry) and the welding heat input. For this analysis, inclusions engulfed by one ferrite grain and those shared by two ferrite grains were considered as the IPF nucleants, and the rest of them (in contact with more than three ferrite grains) were considered as the IAF nucleants. All inclusions were multi-component oxides having Ti oxides as the nucleoid. The inclusion size exhibited a log-normal distribution and the average size increased as the heat input increased. Inclusions larger than ~0.4 μm were found to be effective on IAF nucleation, and the effectiveness increased as the inclusion size increased. Accordingly,the overall IAF nucleant fraction increased as the heat input increased due to the corresponding inclusion size increase. However, the probability of the IAF nucleant in the same inclusion size range was insensitive to the heat input. There was no difference in the elemental distribution between the IAF and IPF nucleants except for Si. The Si distribution was uniform in the IPF nucleants while its content was relatively high at the inclusion periphery in the case of the IAF nucleants regardless of the heat input and the inclusion size.

조혈모세포이식 환자에서 침습성 진균 감염에 대한 Micafungin의 예방 효과 및 안전성

김시현,이동건,최수미,권재철,박선희,최정현,유진홍,이성은,조병식,김유진,이석,김희제,민창기,조석구,김동욱,이종욱,민우성,박종원 대한감염학회 2010 감염과 화학요법 Vol.42 No.3

Background: Micafungin, a potent inhibitor of 1,3-β-D-glucan synthase, is a novel antifungal agent of the echinocandin class. In vitro study showed that micafungin was effective against Aspergillus species as well as Candida species, but clinical data on the prophylactic efficacy against invasive fungal infections (IFIs) other than candidiasis are still lacking. Materials and Methods: We identified 60 consecutive adult hematopoietic stem cell transplantation (HSCT) recipients who received at least 3 doses of micafungin during neutropenic period. Micafungin was started as an alternative in patients who were intolerant or had adverse events (AEs) to primary prophylactic antifungal agents. We retrospectively reviewed the medical records and analyzed the efficacy and safety of micafungin for prophylaxis against IFIs. Results: The patients either had autologous (n=9) or allogeneic (n=51: 1 syngeneic, 24 sibling, 26 unrelated donor) HSCT. Itraconazole oral solution (n=58) was the most frequently used first line antifungal agent for prophylaxis and was administered for median 11 days. The most frequent cause of switch to micafungin was vomiting (n=42). The duration of neutropenia and micafungin administration was median 13 and 12 days, respectively. A successful outcome was achieved in 45 (75%) patients. Empirical antifungal therapy was initiated in 13 (22%) patients. There were 2 cases (3.3%) of breakthrough fungal infections which comprised a probable invasive pulmonary aspergillosis and a possible invasive fungal sinusitis. There was no case of invasive candidiasis. A total of 53 (88%) patients experienced at least one AE regardless of causality during micafungin administration. The most frequent AEs were hypokalemia, vomiting, diarrhea, and elevated serum aspartate aminotransferase or alanine aminotransferase. Among the aforementioned AEs, only 1 case of diarrhea could be classified as a probable relation with micafungin when causality was assessed. There was no AEs that caused discontinuation of micafungin. Conclusions: Micafungin seems to be a safe and effective agent for prophylaxis of IFIs including aspergillosis as well as candidiasis in HSCT recipients. However, further large, prospective, and randomized comparative studies are warranted for aspergillosis.

MWPC를 이용한 X-선 이미지 센서의 개발

박정병,문명국,이동명,구성모,조진호,김도성,우홍,도시홍,이상윤,강희동 경북대학교 센서기술연구소 1994 센서技術學術大會論文集 Vol.5 No.1

A digital X-ray image sensor system is described. A one-coordinate multiwire proportional counter plays the part of X-ray positioning sensor. This measures the distribution of X-ray intensity in horizontal direction with a 2mm channel. A two-dimensional image is produced by mechanical scanning with 2mm channel width in vertical direction. The number of pixels in the image is 32x32. The main characteristics of the sensor are: spatial resolution 1.4mm, counting rate capability 120kHz.

分割施工되는 프리스트레스트 콘크리트桁橋의 長期擧動

李容準,李明雨,朴英錫,鄭時潤 명지대학교 공학기술연구소 1991 공학기술연구소 논문집 Vol.6 No.-

Numerical model for predicting the deflections and stress distribution due to creep and shrinkage of concrete and relaxation of prestressed steel of the segmentally erected indeterminate prestressed concrete bridge is presented in this paper. The computer program considering the presence of the reinforcement, the difference in ages of the concrete segments, the multiple stages in which the external loads and prestressing forces are applied, and the changes in geometry and support conditions as the construction progresses is developed. The proposed method is applied to a three-span continuous bridge and four-span continuous bridge, and the results indicate the significance of the time-dependent effects.