• 한국환경보건학회지
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• 제28권5호
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• pp.59-64
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• 2002

The photocatalytic decolorization of the Rhodamine B (RhB) was studied using a UV/TiO$_2$ reactor. Yakuri titanium dioxide(anatase) was used as the suspended photocatalyst and proved to be effective for decolorization irradiated with UV light (254 mm). The photocatalyzed dioxide concentrations, light intensity and air flow rates. In 0.01 mM RhB, color could be completely photodegraded after 3 hours. Absorption spectrum of an aqueous solution containing RhB showed a continued diminution of the RhB concentration in the solution bulk : concomitantly, no new absorption peaks appeared. This confirmed the decolorization of RhB, i.e., the break up of the chromopore. The optimum loaded titanium dioxide for the decolorization was 0.75 g/(equation omitted). The light intensity showed exponential decay with distance. The decay of light intensity of RhB solution showed different tendency from TiO$_2$. These results suggested that the photocatalytic decolorization of dyes may be available method for decolorizing in wastewater.

• Journal of Mechanical Science and Technology
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• 제17권11호
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• pp.1599-1607
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• 2003

The characteristics of elastic waves emanated from crack initiation in 6061 aluminum alloy subjected to fatigue loading are investigated through experiments. The objective of the study is to determine the differences in the properties of the signals generated from fatigue test and also to examine if the sources of the waves could be identified from the temporal and spectral characteristics of the acoustic emission (AE) waveforms. The signals are recorded using nonresonant, flat, broadband transducers attached to the surface of the alloy specimens. The time dependence and power spectra of the signals recorded during the tests were examined and classified according to their special features. Six distinct types of signals were observed. The waveforms and their power spectra were found to be dependent on the crack propagation stage and the type of fracture associated with the signals. The potential application of the approach in health monitoring of structural components using a network of surface mounted broadband sensors is discussed.

• 한국지구과학회지
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• 제33권5호
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• pp.395-400
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• 2012

One of the main problems concerning the shallow seismic survey is how to generate high frequency signals with large amplitudes using small seismic sources. If one could focus the seismic energy in the direction of the survey line, it will be much helpful in identifying the first break. In this research, we have used hammer as an impulsive source and compared the signal powers generated by different shapes of the hammer plates: circular, square, and rectangular. The experiment was conducted by calculating the power spectral density function to compare the frequency spectrum and signal power. In the direction perpendicular to the long side of the rectangular plate, the largest seismic energy with the highest frequency was achieved even with the same weights of hammer plates. Our conclusion is that it is more efficient to use a rectangular plate than a circular (or square) one when conducting a 2-D shallow seismic survey.

• 천문학논총
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• 제30권2호
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• pp.417-421
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• 2015

We analyzed 0.5-45 keV data of NGC 3227 observed by Suzaku six times between 2008 October 28 and December 2. The count-count plot between the 0.5-3 keV and 3-10 keV bands exhibits a clear break, separating the data into bright and faint phases. Applying the difference spectrum method and time-averaged spectral fits to the phase data, we found the presence of two kinds of variable primary X-rays, (1) a hard primary component with ${\Gamma}{\sim}1.7$ dominating in the faint phase and (2) a soft primary continuum with ${\Gamma}{\sim}2.4$ appearing in the bright phase, both affected by partial absorption. Considering their timing and spectral characteristics, component (1) is presumably identical to a Compton continuum in the low/hard state, while component (2) may correspond to the hard tail emission in the high/soft state, or compact-jet emission. In that case, an accretion ow onto the central super massive black hole in NGC 3227 can be interpreted to include the two different states.

• Bioinformatics and Biosystems
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• 제1권2호
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• pp.109-114
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• 2006

프로테오믹스에서 얻는 탄뎀 질량 스펙트럼은 효소로 가수분해된 펩타이드의 전구이온(precursor ion) 분자량과 펩타이드에 에너지를 가하여 생성된 이온조각(fragment ion)들의 분자량값들로 구성된다. 탄뎀 질량스펙트럼의 전구이온 분자량은 단백질 서열 데이터베이스에서의 검객 과정에서 가장 먼저 고려하는 값이다. 단백질 검색 프로그램은 단백질 서열 중에 스펙트럼의 전구이온으로부터 계산된 분자량과 일치하는 펩타이드 서열들을 찾아내고, 이들 중의 하나를 이온조각들의 분자량 정보를 이용해서 선택한다. 이 때에 전구이온의 분자량은 사용자가 지정한 오차범위 내에서 일치하는 감을 검색하는데, 이때의 오차범위는 질량분석기의 정확도에 따라 결정된다. 본 논문에서는 인간 혈액의 혈장시료로부터 FT LTQ 질량분석기를 통해 얻어진 탄뎀 질량 스펙트럼에서 전구이온 분자량의 분포를 역순서열을 이용하여 분석하였다. 전구이온 분자량의 분포를 재해석하여 실험값의 정확도를 보정하고 단백질 동정의 성능을 향상시키는 방법을 모색하였다.

• Nuclear Engineering and Technology
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• 제41권7호
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• pp.945-952
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• 2009

The Three Mile Island Unit 2 (TMI-2) accident provides unique full scale data, thus providing opportunities to check the capability of codes to model overall plant behavior and to perform a spectrum of sensitivity and uncertainty calculations. As part of the TMI-2 analysis benchmark exercise sponsored by the Organization for Economic Cooperation and Development Nuclear Energy Agency (OECD NEA), several member countries are continuing to improve their system analysis codes using the TMI-2 data. The Republic of Korea joined this benchmark exercise in November 2005. Seoul National University has analyzed the TMI-2 accident as well as the currently proposed alternative scenario along with a sensitivity study using the Modular Accident Analysis Program Version 4.03 (MAAP4.03) code in collaboration with the Korea Hydro and Nuclear Power Company. Two input files are required to simulate the TMI-2 accident with MAAP4: the parameter file and an input deck. The user inputs various parameters, such as volumes or masses, for each component. The parameter file contains the information on TMI-2 relevant to the plant geometry, system performance, controls, and initial conditions used to perform these benchmark calculations. The input deck defines the operator actions and boundary conditions during the course of the accident. The TMI-2 accident analysis provided good estimates of the accident output data compared with the OECD TMI-2 standard reference. The alternative scenario has proposed the initial event as a loss of main feed water and a small break on the hot leg. Analysis is in progress along with a sensitivity study concerning the break size and elevation.

• 천문학회보
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• 제40권2호
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• pp.30.1-30.1
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• 2015

Radio relics are diffuse radio sources found in the outskirts of galaxy clusters and they are thought to trace synchrotron-emitting relativistic electrons accelerated at shocks. We explore a diffusive shock acceleration (DSA) model for radio relics in which a spherical shock with the parameters relevant for the Sausage radio relic in cluster CIZA J2242.8+5301 impinges on a magnetized cloud containing fossil relativistic electrons. This model is expected to explain some observed characteristics of giant radio relics such as the relative rareness, uniform surface brightness along the length of thin arc-like radio structure, and spectral curvature in the integrated radio spectrum. We find that the observed surface brightness profile of the Sausage relic can be explained reasonably well by shocks with speed $u_s{\sim}3{\times}10^3km/s$ and sonic Mach number $M_s{\sim}3$. These shocks also produce curved radio spectra that steepen gradually over $(0.1-10){\nu}_{br}$ with a break frequency ${\nu}_{br}{\sim}1GHz$, if the duration of electron acceleration is ~60-80 Myr. However, the abrupt increase in the spectral index above ~1.5 GHz observed in the Sausage relic seems to indicate that additional physical processes, other than radiative losses, operate for electrons with the Lorentz factor, ${\gamma}_e$ > $10^4$.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.344-347
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• 2008

Ocean surface waves may be modified by ocean current and their observation may be severely distorted if the observer is on a moving platform with changing speed. Tidal current near a sill varies inversely with the water depth, and results spatially inhomogeneous modulation on the surface waves near the sill. For waves propagating upstream, they will encounter stronger current before reaching the sill, and therefore, they will shorten their wavelength with frequency unchanged, increase its amplitude, and it may break if the wave height is larger than 1/7 of the wavelength. These small scale (${\sim}$ 1 km changes is not suitable for satellite radar observation. Spatial distribution of wave-height spectra S(x, y) can not be acquired from wave gauges that are designed for collecting 2-D wave spectra at fixed locations, nor from satellite radar image which is more suitable for observing long swells. Optical images collected from cameras on-board a ship, over high-ground, or onboard an unmanned auto-piloting vehicle (UAV) may have pixel size that is small enough to resolve decimeter-scale short gravity waves. If diffuse sky light is the only source of lighting and it is uniform in camera-viewing directions, then the image intensity is proportional to the surface reflectance R(x, y) of diffuse light, and R is directly related to the surface slope. The slope spectrum and wave-height spectra S(x, y) may then be derived from R(x, y). The results are compared with the in situ measurement of wave spectra over Keelung Sill from a research vessel. The application of this method is for analysis and interpretation of satellite images on studies of current and wave interaction that often require fine scale information of wave-height spectra S(x, y) that changes dynamically with time and space.

• Journal of Genetic Medicine
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• 제4권2호
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• pp.133-141
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• 2007

목 적:임상증상으로 정신지체, 발육부진, 소두증 등으로 묘성 증후군(Cri du Chat syndrome, CdCs)으로 의뢰된 20명 환자와 부모를 포함한 분자 및 세포유전학적 결과를 분석하므로, 유전형과 표현형과의 상관관계를 고찰하고자 하였다. 방 법:환자와 부모에 대해 분자세포유전학적(FISH, CGH array)및 세포유전학적 분석을 시행하였고, 이와 함께 임상양상에 대한 비교분석을 시행하였다. 결 과:20명 환자에 대한 5p 결실 양상에 대한 분석 결과 del(5)(p14)이 9명(45%)로 가장 많았으며, del(5)(p13)이 7명(35%), del(5)(p15.1)(15%)이 3명, del(5)(p15.2)이 1명(5%) 순의 결실 양상을 확인하였다. 또한 4명(20%)에서는 5p 결실 외에 다른 염색체(6, 8, 18, 22번)의 결실과 중복이 있음이 확인 되었고, 이중 3명의 환자는 부모 중 한 사람의 균형적 전자에서 기원한 불균형 전자 유형이었다(기원은 부계 2명, 모계 1명). 그리고 5p 결실 부위와 다른 염색체 이상 공존 여부에 따라 매우 다양한 임상적 양상을 나타내었다. 결 론:이와 같이 묘성증후군 환자와 부모를 포함하는 5번 염색체 단완의 결실양상에 대한 분자 세포 유전학 분석에 의한 정확한 결실 부위의 확인과 다른 염색체 이상의 결손과 증폭의 공존 여부를 확인함으로써 유전형과 임상적 표현형과의 상관관계를 이해하는데 유용할 것이라 생각된다. 나아가 묘성 증후군 환자와 가족에 대한 효과적인 유전상담에 도움이 될 것이라 사료된다.

• 식물병연구
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• 제7권2호
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• pp.86-92
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• 2001

최근(1999∼2000년도) 남부지방에서 벼도열병이 심하게 발생된 원인을 분석한 결과, 잎도열병과 이삭도열병의 발병정도는 1998년에 비해 각각 1.5, 2.9배 증가되었다. 이시기는 밀양95호를 모본으로 육성된 대산, 동안, 일미벼의 재배면적 비율이 전국평균 11%(1998)에서 38.4%(2000)로 급격히 증가되었으며, 특히 전남지역에서는 2000년도 벼재배면적의 85%이상을 차지하였다. 농가포장의 도열병균 레이스 분포는 1998년의 우점레이스 KJ-301이 1999∼2000년도에는 KI-1117, KI-1113, KJ-105 레이스로 바뀌었으며, 남부지방에서의 세 레이스 분포비율은 1998년 1.7%에서 1999년에는 30%로 증가되었다. 대산, 동안, 일미벼는 기존의 주요 레이스에 대하여 저항성이었으나, KI-1117등 3개 레이스에 대해서는 균주에 따라 이병성과 저항성 반응을 나타내고 있었다. 따라서, 대산벼를 참고품종으로 하여 저항성 반응을 보이는 균주는 기존의 KI-l117, KI-1113, KJ-105로 분류하였으며, 이병성 반응을 보이는 균주는 새로운 레이스인 KI-1117a, KI-1113a, KJ-105a로I 명명하였다. 따라서, 최근 남부지방의 도열병 격발은 KI-1117a, KI-1113a, KJ-l05a 레이스의 급격한 증가에 따른 대산벼 등 밀양95호 모본 품종의 이병화에 의한 것이었다.