• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.36.2-36.2
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• 2015

We report the first detection of linearly polarized emission at an observing wavelength of 350 mum from the radio-loud active galactic nucleus 3C 279. We conducted polarization observations for 3C 279 using the SHARP polarimeter in the Caltech Submillimeter Observatory on 2014 March 13 and 14. For the first time, we detected the linear polarization with the degree of polarization of $13.3%{\pm}3.4%$ (3.9sigma) and the electric vector position angle (EVPA) of $34.^{\circ}7{\pm}5.^{\circ}6$. We also observed 3C 279 simultaneously at 13, 7, and 3.5 mm in dual polarization with the Korean very long baseline interferometry (VLBI) Network on 2014 March 6 (single dish) and imaged in milliarcsecond (mas) scales at 13, 7, 3.5, and 2.3 mm on March 22 (VLBI). We found that the degree of linear polarization increases from 10% to 13% at 13 mm to 350 mum and the EVPAs at all observing frequencies are parallel within < $10^{\circ}$ to the direction of the jet at mas scale, implying that the integrated magnetic fields are perpendicular to the jet in the innermost regions. We also found that the Faraday rotation measures RM are in a range of $-6.5{\times}102{\sim}-2.7{\times}103$ rad m-2 between 13 and 3.5 mm, and are scaled as a function of wavelength:| {RM}| ${\backslash}propto$ {lambda }-2.2. These results indicate that the millimeter and sub-millimeter polarization emission are generated in the compact jet within 1 mas scale and affected by a Faraday screen in or in the close proximity of the jet.

• Journal of Korean Society for Atmospheric Environment
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• v.11 no.3
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• pp.221-231
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• 1995

산업발달에 따라 불가피하게 생성되며, 대기오염의 주종을 이루면서 인체에 가장 유해한 분진입자는 산업체의 오일(oil) 및 석탄연소 보일러, 자동차, 제철/제강 및 시멘트 플랜트 등으로 부터 배출되는 미세입자(fine particle)들이며, 앞으로 이들의 제어에 관한 연구가 지속적인 관심의 대상이 될 것이다. 한 예로, 석탄연소 화력발전소로부터 1$\mum$ 이하의 입자들의 배출량은 무게비로는 1% 이하이지만 입자수의 비율에서는99%를 차지하고 있다. 이들은 매우 높은 중금속 함유량을 지니고 있기 때문에 인체의 호흡시 심각한 문제를 유발시킬 뿐만 아니라, 이러한 미세입자들은 대기중에 부유하고 있다가 비(rain)에 의하여 세정되어 수질오염까지도 유발시킨다. 1992년 2월 공포된 대기환경보전법 시행규칙에 따라 분진배출 허용기준이 장기 입법예고 되므로서 1995년 1월과 1999년 1월의 2단계에 걸쳐 현재 적용 받고 있는 분진배출 규제치보다 훨씬 낮은 선진국 수준의 분진배출 규제가 요구되고 있으며, 분진이 배출되는 인근지역주민의 민원에 대처하기 위해서는 연돌로부터 분진배출이 눈에 감지되지 않을 정도까지 분진배출농도를 관리해야할 필요성이 높아지고 있다. 이에 따라 집진장치의 효율도 중유전소 Boiler 의 경우는 90% 이상, 석탄전소 Boiler의 경우는 99.5% 이상의 고효율이 요구되고 있다.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.7
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• pp.37-45
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• 1998

A 32-b self-timed parallel carry look-ahead adder (PCLA) designed for 0.5.mum. single threshold low power CMOS technology is demonstrated to operate with 2.7nsec delay at 8mW under 1V power supply. Compared to static PCLA and DPL adder, the self-timed PCLA designed with NORA logic provides the best performance at the power consumption comparable to other adder structures. The wave pipelined clock control play a crucial role in achieving the low power, high performance of this adder by eliminating the unnecessary power consumption due to the short-circuit current during the precharge phase. Th enoise margin has been improved by adopting the physical design of staic CMOS logic structure with controlled transistor sizes.

• Journal of Environmental Science International
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• v.7 no.2
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• pp.123-132
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• 1998

The experiment was performed to elucidate the effect of simulated acrid rain on growth of the seven crops(caucus carota vu sativa DC. , Fagopyrum esculenkm Moench, Brassica cmpespis subsp. napus var. pekinensis Makino , Raphuus satlws vu. hortensis for. acnMormis Makino, Brassica dbogjabra Bailey, Caphslcum mum L., and Perilla frutescens Britton). The pH levels of simulated acid rain ranged pH 3.1, 3.6, 4.1, 4.6, 5.1 and 5.6. The germination 10 each crop was influenced from stimulated acrid rain except buckwheat and kale. A general decrease of growth in crops was observed with Increasing pH concentrations. The pattern of soluble protein was observed a tendency to decrease from acidic pH eradlents. According to acidity, total DNA contents of each crop was showed a definite reduction. In conclusion, plant growth was stimulated decreasln and the chanties of total Protein Patterns and BNA contents extracted from leaves trended with stimulated acrid rain was showed seriously.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.10a
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• pp.130-132
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• 1998

정밀여과막(MF)막은 $0.1~1\mum$정도의 공경을 가지고 있는 막으로 산업이나 생활분야에서 널리 사용되고 있다. 이러한 정밀여과막에 이온교환기를 부여 시키므로써, 필요로하는 금속이온이나 단백질을 흡착할 수 있는 기능성 분리막이 제조 가능하다. 방사선프라프트 중합법은 고분자를 개질, 수식 또는 기능화시키는 수법으로 사용되고 있다. 본 실험에서는 방사선그라프트중합법을 사용하여 폴리에틸렌 정밀여과막에 에폭시기를 가지는 glycidyl methacrylate(GMA)를 그라프트 중합시킨 후 이온 교환기를 도입하여, 얻어진 막의 특성에 대해 고찰하였다. 본실험의 목적은 다음과 같다. (1) 폴리에틸렌 정밀여과 막에 방사선그라프트 중합법을 사용하여 이온교환기를 도입시키는 반응조건을 검토한다. (2) 도입된 이온교환기에 다른 막의 투과 성능을 조사한다. (3) 투과법에 의한 금속이온의 흡착성능을 조사한다. 여기서, 이온교환기로서는 술폰산(sodium sulfite:$SO_3H$)을 사용하였다.

• Korean Journal of Computational Design and Engineering
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• v.8 no.1
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• pp.19-26
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• 2003

This paper presents the structural analysis of RIROB(Reactor Inspection Robot). Actually, several analyses such as kinetodynamics analysis, fluid mechanics analysis and structural mechanics analysis etc. should be carried out in the design of RIROB. These analyses are executed through the use of com-puter aided engineering(CAE) systems. The kinetodynamics analysis is carried out using a simple fluid dynamic analysis model for the water flow over the sensor support surface instead of difficult fluid mechanics analysis. Simultaneously the structural mechanics analysis is carried out to obtain the mini-mum thickness of the RIROB housing. The minimum thickness of the RIROB housing is evaluated to be 1.0 ㎝ for the safe design of RIROB. The kinetodynamics analysis of RIROB is performed using ADAMS and the static structural mechanics analysis of RIROB is performed using NISA.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.1
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• pp.21-26
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• 1991

the Bacillus subtilis LY-353 which secretes the protease isolated from seafoods. The opti-mum culture condition for production of protease from B. subtilis LY-353 was as follows ; tem-perature 35$^{\circ}C$ pH 7.5 salt concentration 1.0% The purification steps involved ammonium sulfate fractionation DEAE-Sephadex A-50 column chromatography and Sephadex G-100 gel filtration A 7.33 fold purification and 6.55 yield of protease was obtained from culture broth, The optimum pH and temperature for the enzyme action were pH7.5 and 55$^{\circ}C$ respecti-bely.

• 연구논문집
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• s.29
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• pp.163-171
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• 1999

A new titanium alloy system. Ti-xFe-ySi (x,y=0-4 wt%). was designed and characterized with the point at low cost and high strength for casting applications. Fe improved room and elevated temperature mechanical properties owing to solid solution hardening and beta phase stabilization. Si yielded titanium silicides and Si addition over 1 wt% resulted in poor ductility due to coarse silicide chains at prior beta boundaries. The optimum composition was found to be Ti-4Fe-(0.5-1)Si in the viewpoint of tensile strength and ductility which are comparable to the Ti-6Al-4V. The metal-mould reaction was also examined for Ti-xFe and Ti-xSi binary alloy system. The thickness of surface reaction layer w as not affected significantly with Fe content, while it was decreased with Si content. In the Ti-4Si alloy, no reaction layer was found. The depth of surface hardening layer was about $200\mum$ regardless of the mould materials.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.458-461
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• 2003

Solid-phase microextraction (SPME) and gas chromatography/headspace techniques(HS) and flame ionization detection (GC/FID) have been combined for determination of very polar compounds in water, including the widely used gasoline oxygenates and by-products. A relatively simple extraction method using a CAR/PDMS(75${\mu}{\textrm}{m}$) SPME fiber was optimized for the routine analysis of gasoline oxygenates and by-products in groundwater and reagent water. A sodium chloride concentration of 25%(w/w) combined with an extraction time of 20 min provided the greatest sensitivity while maintaining analytical efficiency Replicate analyses in fortified reagent and groundwater spiked with microgram per liter concentrations of gasoline oxygenates and by-products indicate quantitative and reproducible recovery of these and related oxygenate compounds. Method dynamic range was 50$\mu\textrm{g}$ L-1 to 3000$\mu\textrm{g}$ L-1 for gasoline oxygenates and by-products.

• The Journal of Natural Sciences
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• v.14 no.2
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• pp.25-31
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• 2004

레이저 거리 측정기나 화생탐지 라이다용으로 사용할 수 있는 눈에 안전한 적외선 레이저 광원을 개발하였다. 펌프레이저로는 소형 플래쉬 램프로 구동되는 Nd:YAG 레이저를 사용하였으며, OPO(Optical Parametric Oscillator) 결정으로는 Flux 성장된 KTP를 사용하였다. OPO 송진기는 레이저 공진기 내부에 설치하여 비선형 광학 현산에 의한 파라메트릭 발진이 쉽게 일어나도록 하였다. 효율적인 파라메트릭 발진을 위해서 Type II 비임계 위상정합$(\theta=90^{\circ},\;\phi = 0^{\circ})$을 사용하여 공진기를 구성하였다. Nd:YAG 레이저는 Cr:YAG 결정을 사용하여 수동형 큐-스위칭 되었으며 OPO 출력은 1mJ 정도이었다. OPO 펄스폭은 4ns로서 수동형 큐스위칭 레이저 펄스폭보다 20% 정도로 작았다. OPO 출력의 펄스폭이 펌프레이저의 펄스폭 보다 작은 것은 이론적 계산을 통하여 확인할 수 있었다.