사이드 스트림 방식의 막 모듈을 대상으로 유입 유량을 수직으로 균등하게 분포시킬 수 있는 방안을 CFD로 설계한 결과, 내부 유입 수리구조에 유공 격벽 을 설치함으로써 모듈내로의 유입유량은 표준편차 기준으로 약 40% 정도 감소 됨을 확인하였다. 또한 CFD 결과를 검증하고 사이드 스트림 막 모듈의 편중된 오염의 원인을 조사하기 위해 수행된 입자영상유속 측정 결과로부터 유입구 반대편 유공에서 막 모듈 내부로 들어오는 수체의 유속이 상대적으로 커 수체의 모멘텀이 유입구 측벽에 강한 전단력을 발생하지만 유입구 반대 측벽에서는 사류가 형성됨을 확인하였다.
A supercritical carbon dioxide (SCC) process of dispersion of multi-walled carbon nano-tubes (MWCNTs) into epoxy resin has been developed to achieve MWCNT/epoxy com-posites (CECs) with improved mechanical, thermal, and electrical properties. The synthesis of CECs has been executed at a MWCNT (phr) concentration ranging from 0.1 to 0.3 into epoxy resin (0.1 mol) at 1800 psi, 90°C, and 1500 rpm over 1 h followed by curing of the MWCNT/epoxy formulations with triethylene tetramine (15 phr). The effect of SCC treat-ment on the qualitative dispersion of MWCNTs at various concentrations into the epoxy has been investigated through spectra analyses and microscopy. The developed SCC assisted process provides a good dispersion of MWCNTs into the epoxy up to a MWCNT concentra-tion of 0.2. The effects of SCC assisted dispersion at various concentrations of MWCNTs on modificationof mechanical, thermal, dynamic mechanical thermal, and tribological proper-ties and the electrical conductivity of CECs have been investigated.
This study mainly inquired characteristics and changes of 'Chang-aelgool' through 38 cases(with 161 Ssang-chang) of annex and pavillion buildings in Yeong-nam region which are built during the Chosun dynasty. The method of inquiry included actual survey of windows along with bibliographical research, and the results are as below. First, through the discovery of the term 'Chang-aelgool' as an indication of the window-forming frame in 'YeongGeonUiGwe'(1680 A.D), it is apparent that the term 'Chang-aelgool' was widely used in Korea from the late 17th century. Second, the 'Chang-aelgool' of study objects are classified into 4 categories. Type Ⅰ and Ⅱ are comprised of mitre-joints which cover the 4 corners of 'Chang-aelgool' and mainly used in building annex and pavillion buildings during the early period of the Chosun dynasty. Type Ⅲ was widely used during the early and middle period of the Chosun dynasty and drastically dropped in number during the late period of the dynasty. Type Ⅳ is comprised of mitre-joint of the upper-half, tenon-jointing of the lower-half and widely used in annex and pavillion building during the late period of the Chosun dynasty. Third, the form of 'Chang-aelgool' has changed from rectangular form with longer width during the early period of Chosun dynasty to square form during the middle period and eventually ended up as a rectangular form with longer height during the late period of the dynasty. Fourth, it is considered that while mullion which is located in the center of 'Chang-aelgool' was mainly used around the main floored room during the early period of the Chosun dynasty, became commonly used in main floored room and 'ondol' rooms during the middle period and drastically dropped in number from then and ended up being not in use after the mid 18th century.
기존의 공진주 비틂 전단 시험기는 길이와 지름의 비율이 2:1의 시료를 사용하고 이는 가진 시스템의 최대 회전시 대략 1.5%의 최대 전단 변형율을 일으킨다. 이번 연구의 목적은 대변형을 일으킬수 있는 공진주 비틂 전단 시험기의 수정이다. 수정 작업으로는 가진시스템의 왕복거리 한계의 극복을 위한 새로운 기초 받침 개발과 비틂력을 증가시키기 위한 코일 감는 방법의 변형이다. 가진 시스템의 새로운 코일감는 방법이 전자석 시스템에서 비틂력에 미치는 영향이 평가 되었고 모래를 시험한 수정된 장치의 응용이 기술되었다.
요즘 한국 문화와 한국어에 대한 관심을 갖고 배우는 학습자들이 급증하고 있다. 한국어를 배우는 과 정에서 한국어 발음을 먼저 배우는 것은 필수적이다. 한국어를 처음 접하는 학습자들에게는 한국어 표 준 발음법을 통해 한국어 발음이 정확한지를 판단할 수밖에 없다. 그 계기로 국립국어원에서 『한국어 문규정』을 재정하였다. 표준 발음법과 관련된 규정은 『한국어문규정』에서 다루고 있는 것으로 확인할 수 있다. 그러나 표준 발음법을 자세히 살펴보면 여러 가지 문제점들이 드러나 있다. 전문가들은 이에 대해 수차례를 수정하였지만 문제점이 여전히 존재한다는 것이 사실이다. 본 연구는 『한국어문규정』 에서 다루고 있는 표준 발음법을 가지고 연구를 진행하려고 했다. 이 중에 흥미로운 것은 바로 제12항 에서 다루는 ‘ㅎ’과 관련된 조항들이다. 제12항에서 ‘ㅎ’과 관련된 내용을 따로 규정한 것은 ‘ㅎ’의 복잡 성과 특수성을 가지고 있기 때문이다. 비록 ‘ㅎ’ 관련 내용을 따로 규정하였지만 내용 표현, 음운 현상, 예문 제시에 있어서 많은 문제점이 존재할 뿐만 아니라 많은 학자들도 이에 대해 많은 의견을 제시하였 으나 심층적으로 다루지 못하였다. 따라서 본 연구는 표준 발음법 제12항에 대해 자세히 분석하고 이 를 바탕으로 수정 방안도 함께 제시하였다.
The surface properties and adsorption rates of activated carbon modified with acid and base were compared. The distribution ratio of C and C-H on the surface of activated carbon were decreased by modification with acid and base, but the distribution ratio of C-O, C=O, and O=C-O were increased. Base modification damaged the surface of activated carbon more than acid modification, it caused the effect of 6 percent increments of surface area. Adsorption rate model was more suitable to second order equation than first order equation. Adsorption rate was controlled by adsorption in pore better than in surface.
There is a need to improve the efficiency of the existing sanitary treatment facilities, because the effluent standard becomes more stricter and septic sludge increased. Thus, operating processes of sanitary treatment system in M city changed with installation of additional facilities. Process modifications were as follows: Dilution water was added to the next process after primary aeration tank. Some secondary sedimentation sludge was recycled to primary aerator so that most of the organics were stabilized in primary aeration tank under automatic control of dissolved oxygen. The line of effluent from dewatering process flowing to the activated sludge tank was changed to the primary aerator. The primary sedimentation sludge line was linked to a thickener. Polymer was added to the activated sludge tank. The effluent of primary aerator and aerobic digester was recycled from the 5th to the 1st sector. As consequencies of above process modifications, the improvement of removal efficiency was achieved as BOD 54%, COD 42%, SS 61%, T-N 39%, and T-P 12%, respectively.