• Membrane Journal
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• v.19 no.3
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• pp.252-260
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• 2009

The effects of the treatment of an acidic solution at pH 2 on polyacrylonitrile ultrafiltration (UF) membranes were investigated using a circular cross-flow filtration bench with a membrane module. A substantial reduction in the membrane permeability was observed after 80 hours' treatment of the acidic solution. In addition, the analyses of the sample solutions by ultraviolet/visible absorption spectroscopy and gas chromatography/mass spectrometry (GC/MS), which were taken from the feed tank as a function of the treatment time, showed that a new organic compound was produced in the course of the treatment. From a thorough search of the mass spectral library we presumed the new compound to be 1,6-dioxacyclododecane-7,12-dione (DCD), one of the well-known additives for polyurethane. Based on further experimental results, including the scanning electron microscope (SEM) images and the solid-state NMR spectra of the membranes used for the treatment of the acidic solution, we suggested that the decrease of the permeate flux resulted not from the deformation of the membranes, but from the fouling by DCD eluted from the polyurethane tubes in the filtration bench during the treatment. Those results imply that the reactivity to an acidic solution of the parts comprising the filtration bench is as important as that of the membranes themselves for effective treatments of acidic solutions, for efficient chemical cleaning by strong acids, and also in determining the pH limit of the solutions that can be treated by the membranes.

• Korean Journal of Environment and Ecology
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• v.26 no.4
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• pp.559-575
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• 2012

This study, targeting Namhan Mountain Fortress which was designated as a No. 57 national historic site and placed on the World Heritage Tentative List in 2010, was intended to identify the change of vegetation structures by reviewing past references, pictures, research data and additionally conducting a site survey. Also, it was designed to draw up measures for restoring vegetation suitable for historically and culturally valuable Namhan Mountain Fortress. According to the biotope mapping of study site, Quercus spp. forest distributed a greatest part of area with 40.8% of $2,611,823m^2$. Pinus densiflora forest, highly likely to go through ecological succession, was dispersed in the whole region of Cheongryangsan, the area from West Gate to North Gate and the ranges between South Gate to Cheongryangsan with taking 16.5%. Pinus densiflora forest with a low probability of succession amounted to 4.7% and was dispersed mainly in the forest behind Namhansan elementary school. Pinus densiflora going on the ecological succession is distributed a portion of 2.9%. And the currently dying out Pinus densiflora forest amounted to 2.1%. As a result of analysis of the vegetation structure for 19 years, the succession from Pinus densiflora forest to Pinus densiflora and succession from Quercus spp. mixed forest to Quercus spp. forest to Carpinus laxiflora forest were predicted. Additionally, Quercus spp. expanded its dominance over time. According to the characteristics of each classified zone, the site was categorized into $553,508m^2$ area of Pinus densiflora forest area for the landscape maintenance, $114,293m^2$ area of Pinus densiflora forest area for the landscape restoration, $205,306m^2$ area of Pinus densiflora forest area for the disclimax, and $1,169,973m^2$ area of Pinus densiflora forest area for inducing ecological succession.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.53-54
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• 2003

현대 산업사회가 다양해짐에 따라 발생되는 생활폐기물의 형태도 다양화되었고 발생폐기물의 성상은 연소가 어려운 난분해성 폐기물로 발열량이 높아지고 있다. 이러한 폐기물의 처리를 위한 소각설비는 폐기물 처리형태에 따라 대형의 도시 쓰레기 소각장이나 지자체의 중형급 소각장, 발생원 단위의 소형 소각장으로 구분하여 처리하고있다. 기존 중ㆍ대형 소각로의 유해가스 처리시설은 일반적으로 냉각설비와 가스상 처리설비, 입자상 처리설비 등으로 구성되는데 반해, 소형 소각로는 싸이클론 방식만으로 구성되어 입자상 물질만을 처리하였으나, 최근에 들어서 관련법규가 개정되어 소형 소각로에서도 입자상 오염물질뿐만 아니라 HCl 및 SOx 등과 같은 산성가스류와 다이옥신 등의 배출농도를 규제함에 따라 가스상 오염물질도 처리하는 방안을 도입하고 있는 추세이다. (중략)

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.4
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• pp.319-325
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• 1991

A nonparametric detection scheme which uses rank statistics for detection of known signals is considered in a special case of a generalized observation model. Specifically locally optimum rank detectors for detection of known deterministic singals in a singnal-dependent noise model are derived, and compared to those derived for the purely-additive noise model. Examples of the score functions are given, which constitutes the test statistics of the locally optimum rank detectors.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.11
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• pp.1125-1131
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• 1991

In a generalized model with which we can represent multiplicative noise as well as purely additive noise, we consider detection of composite signals which contain both deterministic and stochastic signal components. To illustrate the performance of the locally optimum detectors, finite sample-size performance characteristics are obtained and compared with those of other detectors.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.3
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• pp.272-277
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• 2004

The primary aim of this study is to investigate new semi-abrasive free slurry including acid colloidal silica and hydrogen peroxide for copper chemical-mechanical planarization (CMP). In general, slurry for copper CMP consists of colloidal silica as an abrasive, organic acid as a complex-forming agent, hydrogen peroxide as an oxidizing agent, a film forming agent, a pH control agent and several additives. We developed new semi-abrasive free slurry (SAFS) including below 0.5％ acid colloidal silica. We evaluated additives as stabilizers for hydrogen peroxide as well as accelerators in tantalum nitride CMP process. We also estimated dispersion stability and Zeta potential of the acid colloidal silica with additives. The extent of enhancement in tantalum nitride CMP was verified through anelectrochemical test. This approach may be useful for the application of single and first step copper CMP slurry with one package system.

• The Korean Journal of Zoology
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• v.1 no.2
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• pp.1-5
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• 1958

1. 저자가 1957년 5월부터 1958년 9월까지 남한 10개지역 즉 광릉(경기도), 네주도, 오대산(강원도), 울릉도, 강화도, 작약도(경기도), 주안(경기도 ), 이리(전북), 홍릉(서울), 남한산성(경기도)에서 복숭아, 사과등의 과실 Trap 방법과Sweeping 법으로 채집한 초파리는 4 속, 7 아문, 44종 2198 마리였다. 2. 급번채집에서 얻은 한국산미기록종은 D.(H.) trivittata Strobl Mycodrosophila splendida okada, D.(S.) auraria Peng(Type C)의 3 종이며 미지 10 종은 현재 검색중이거니와 그 결과는 멀지않아 발표할 예정이다. 3. 울릉도채집은 1958년 8월 1일부터 13일까지에 이루어졌으며 채집지는 도동, 사동, 천부, 대무, 남양 난봉, 성인봉이며 그 결과 채집된 22종은 울릉도산동물목록에 새로이 부가하는 바이다.

• Journal of Yeungnam Medical Science
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• v.25 no.2
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• pp.154-159
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• 2008

Angioleiomyoma of the sinonasal tract is a rare benign tumor. We report a case of angioleiomyoma of the nasal septum in a 51-year-old woman who complained of frequent epistaxis for 3 months. Surgicalexcision was performed. The excised specimen was $0.7{\times}0.5{\times}0.4cm$ in size, well circumscribed, grayish white, rubbery, and soft. Histological examination showed thick-walled blood vessels and smooth muscle cell proliferation. No nuclear atypia or mitoses were present.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.9
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• pp.1019-1026
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• 1988

A parametric detection scheme for determenistic signals is obtained in a generalized observation model which contains non-additive noise. The model employed in this paper includes several special cases such as those describing purely-additive noise, multiplicative noise, and signal dependent noise and allows the consideration of deterministic and random signals. Locally optimum detectors for known deterministic signals in the model are derived and analyzed for performance. It is shown that the locally optimum detectors are interesting generalizations of those for the purely-additive noise model. Performance of the locally optimum detectors designed for the generalized observation model is compared to that of other common detectors.

• Journal of Environmental Health Sciences
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• v.26 no.4
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• pp.129-133
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• 2000

The objective of this study was to invetigate the coagulation effects of landfill leachate by using Acid Mine Drainage(AND). The coagulation efficiency was investigated by mixing landfill leachate with F $e^{+3}$ solution earned by oxidation of pyrite(AMD). In the results of this experiment, it was found that the amount of removed COD and SS was approximately 30% respectively by mixing at the ratio of AMD three to leachate one. And it showed highest turbidity removal efficiency at all mixing ratio. Concentration of Fe was decreased with increasing mixing ratio, however it was increased inversely at mixing ratio 4. Optimal mixing ratio was 3 at the results obtained by leachate coagulation experiments. Also removal efficiency at mixing ratio 3 corresponded to 500mg/$\ell$ of FeC $l_3$ dosage. it was suggested that pretreatment by mixing of AMD and leachate remove both suspended organic material of leachate and metal of AMD.