• 한국안전학회지
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• 제30권4호
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• pp.56-63
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• 2015

Gas explosion accidents could cause a catastrophe. we need specialized and systematic accident investigation techniques to shed light on the cause and prevent similar accidents. In this study, we had performed LNG explosion simulation using AUTODYN which is the commercial explosion program and predicted the damage characteristics of the structures by LNG explosive power. In the first step, we could get LNG's physical and chemical explosion properties by calculation using TNT equivalency method. And then, by applying TNT equivalency value about the explosion limit concentration of LNG on the 2D-AUTODYN simulation, we could get the explosion pressure wave profiles (explosion pressure, explosion velocity, etc.). In the last step, we performed LNG explosion simulation by applying to the explosion pressure wave profiles as the input data on the 3D-AUTODYN simulation. As a result, we had performed analyzing of the explosion characteristics of LNG in accordance with concentration through the 3D-AUTODYN simulation in terms of the explosion pressure behavior and structure's destruction and damage behavior.

• Environmental Engineering Research
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• 제12권2호
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• pp.55-63
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• 2007

PCDD/Fs monitoring was carried out to estimate the contamination level in soil samples taken in the vicinity of the various incinerators throughout South Korea from July 2003 to December 2004. The levels ranged from N.D. to 130.39 pg I-TEQ/g (d.w.) with an average concentration of 11.38 pg I-TEQ/g (d.w.). The level of PCDD/Fs in this study is similar to that of other countries. Overall, the highest mean concentration in the soil was found at 250 m from the stack. In addition, the flue gases were analyzed in order to obtain the congener profiles of the PCDD/Fs emitted from the incinerators. The concentration of I-TEQ in the flue gas ranged from 0.33 to 21.5 ng TEQ/$Sm^3$. These levels were much lower than the concentration stipulated in the Korean emission criterion(40 ng TEQ/$Sm^3$ until 2005). The comparison of the congener patterns using cluster analysis showed that the incinerators and PCP are sources of PCDD/Fs in the soil samples according to the sampling point, but the possibility of unidentified combustion sources and vehicles exists in the case of complex industrial regions.

• 천문학회지
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• 제33권1호
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• pp.47-55
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• 2000

Nonpotential characteristics of magnetic fields in AR 5747 are examined using Mees Solar Observatory magnetograms taken on Oct. 20, 1989 to Oct. 22, 1989. The active region showed such violent flaring activities during the observational span that strong X-ray flares took place including a 2B/X3 flare. The magnetogram data were obtained by the Haleakala Stokes Polarimeter which provides simultaneous Stokes profiles of the Fe I doublet 6301.5 and 6302.5. A nonlinear least square method was adopted to derive the magnetic field vectors from the observed Stokes profiles and a multi-step ambiguity solution method was employed to resolve the $180^{\circ}$ ambiguity. From the ambiguity-resolved vector magnetograms, we have derived a set of physical quantities characterizing the field configuration, which are magnetic flux, vertical current density, magnetic shear angle, angular shear, magnetic free energy density, a measure of magnetic field discontinuity MAD and linear force-free coefficient. Our results show that (1) magnetic nonpotentiality is concentrated near the inversion line in the flaring sites, (2) all the physical parameters decreased with time, which may imply that the active region was in a relaxation stage of its evolution, (3) 2-D MAD has similar patterns with other nonpotential parameters, demonstrating that it can be utilized as an useful parameter of flare producing active region, and (4) the linear force-free coefficient could be a evolutionary indicator with a merit as a global nonpotential parameter.

• Journal of electromagnetic engineering and science
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• 제1권1호
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• pp.18-23
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• 2001

A fast-sweep broadband FM reflectometer system has been successfully developed and operacted at the DIII-D tokamak, producing reliable density Profiles with excellent spatial (1 $\leq$ cm) and temporal resolution (~100 $\mu$ s). The system uses a solid-state microwave oscillator and an active quadrupler, covering full Q-band frequencies (33~50 GHz) and providing relatively high output power (20~60 mW). The system hardware allows fu11band frequency sweep in 10 $\mu$ s, but due to digitization rate limit on DIII-D, sweep time was limited to 75~100 $\mu$ s. Fast frequency sweep has helped to reduce density fluctuation effects on the reflectometer phase measurements, thus improving reliability for individual sweeps. The fast-sweep system with high spatial and temporal resolution has allowed to measure fast-changing edge density profiles during plasma ELMS and L-H transitions, thus enabling fast-time sca1e physics studies.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 하계종합학술대회논문집
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• pp.421-424
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• 1998

In this paper are presented a newly proposed 3D monte carlo (MC) damage model for the dynamic simulation in order to more accurately and consistently predict the implant-induced point defect distributions of the various ions in crystalline silicon. This model was applied to phosphorus implants for the ULSI CMOS technology developement. In additon, a newly applied 3D-trajectory split method has been implemented into our model to reduce the statistical fluctuations of the implanted impurity and the defect profiles in the relatively large implanted area as compared to 1D or 2D simulations. Also, an empirical electronic energy loss model is proposed for phosphorus and silicon implants. The 3D formations of the amorphous region and the ultra-shallow junction around the implanted region could be predicted by using our model, TRICSI(Transport ions into crystal-silicon).

• 터널과지하공간
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• 제33권6호
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• pp.495-507
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• 2023

불연속면 거칠기는 암반의 기계적 특성에 큰 영향을 주며 열·수리 역학적 거동에도 많은 영향을 미치는 요소이다. 본 연구에서는 입체사진측량기법을 이용하여 불연속면에 대한 3차원 점군 데이터를 생성시키고 이를 이용하여 불연속면의 거칠기 특성화를 수행하였다. 3차원 점군 데이터로 재생성된 불연속면 프로파일과 프로파일 게이지를 이용하여 수동으로 측정한 프로파일을 비교하여 취득한 점군 데이터가 암반면의 실제 형상을 정확하게 재현하였는지 평가하였다. 또한, 측정 프로파일수가 거칠기 평가에 미치는 영향에 대해 분석하였고, 거칠기의 이방성 평가방법을 제안하고 실제 암반 불연속면에 대한 거칠기 이방성 평가를 수행하였다.

• 한국정밀공학회지
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• 제32권7호
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• pp.633-641
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• 2015

In this study, we proposed a three-dimensional (3D) scanning system based on laser-vision technique and rotary mechanism for automatic 3D model reconstruction. The proposed scanning system consists of a laser projector, a camera, and a turntable. For laser-camera calibration a new and simple method was proposed. 3D point cloud data of the surface of scanned object was fully collected by integrating extracted laser profiles, which were extracted from laser stripe images, corresponding to rotary angles of the rotary mechanism. The obscured laser profile problem was also solved by adding an addition camera at another viewpoint. From collected 3D point cloud data, the 3D model of the scanned object was reconstructed based on facet-representation. The reconstructed 3D models showed effectiveness and the applicability of the proposed 3D scanning system to 3D model-based applications.

• 환경생물
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• 제26권1호
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• pp.42-46
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• 2008

Brassica rapa subsp. pekinensis (배추) 근권에 서식하는 종속영양세균의 군집 밀도 및 군집수준 생리활성을 2곳의 지역에서 각각 측정하였다. 근권의 종속영양세균군집 평균 밀도는 수원이 $2.65\times10^6CFU\;g^{-1}$ soil, 예산이 $3.75\times10^6CFU\;g^{-1}$ soil로 나타났고, 토양은 수원이 $2.45\times10^6CFU\;g^{-1}$ soil, 예산이 $2.97\times10^6CFU\;g^{-1}$ soil로 각각 나타났다. 평균 기능풍부도(functional richness)는 수원이 90.8, 예산이 154.1로 각각 나타났다. 군집 밀도와 기능 풍부도 사이에는 밀접한 상관관계가 보였다. 양쪽 근권에서 가장 활발하게 분해된 기질은 adonitol, L-asparagine, D-gluconic acid, L-glutamic acid와 D-galacturonic acid 등이었으나, 수원과 예산 근권에서의 기질 분해 양상은 뚜렷한 차이를 보였다. 한편 두 곳의 토양 역시 어느 정도 차이를 보였으나, D-raffinose 및 D-mannose는 공통적으로 잘 분해되는 기질로 나타났다.

• Bulletin of the Korean Chemical Society
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• 제35권11호
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• pp.3319-3325
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• 2014

Eu(III)-doped $CeO_2$ nanorods were prepared by a co-precipitation method at room temperature, and their photoluminescence profiles were examined with different Eu(III)-doping concentrations and thermal annealing temperatures. Scanning electron microscopy, X-ray diffraction crystallography and UV-Vis absorption spectroscopy were employed to examine the morphology, crystal structure and photon absorption profiles of the nanorods, respectively. Additionally, their 2D and 3D-photoluminescence profile maps were obtained to fully understand the photoluminescence mechanism. We found that the magnetic dipole $^5D_0{\rightarrow}^7F_1$ and the electric dipole $^5D_0{\rightarrow}^7F_2$ transitions of Eu(III) were highly dependent on the doping concentration, annealing temperature and excitation wavelength, which was explained by the presence of different Eu(III)-doping sites (with and without an inversion center) in the $CeO_2$ host with a cubic crystal structure.

• 생명과학회지
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• 제20권8호
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• pp.1261-1267
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• 2010

본 연구는 체지방을 감소시키는데 효과적이라는 diacylglycerol (DG) 섭취와 유산소운동이 체구성비의 변화 및 혈중지질 개선에 미치는 영향을 규명하고 안정 시 대사량 변화를 관찰함으로써 임상적 및 대사적 측면에서 비만 개선 효과를 규명하는데 그 목적이 있었다. 본 연구의 대상은 의학적으로 다른 질병을 동반하지 않은 비만 남자 대학생으로서 연구의 의의를 충분히 이해하고 자발적으로 참여 의사를 밝힌 사람으로 선정하였으며, 체지방 측정 후 25%미만인 자와 흡연자는 대상에서 제외하였다. 모든 피험자들은 기본검사와 사전검사가 끝난 후 세가지(D, E, DE) 집단에 6명씩 무선 배정하였다. 첫 번째 실험군(D)은 diacylglycerol 섭취 조건으로 12주 동안 diacylglycerol을 섭취하였고, 두 번째 실험군(E)은 12주 동안 러닝 트레이닝을 실시하였다. 마지막 세번째 실험군(DE)은 12주 동안 diacylglycerol 섭취와 유산소 트레이닝을 실시하였으며, 본 연구결과 모든 그룹에서 12주 동안의 그룹별 처치가 진행됨에 따라 체지방이 감소하는 경향을 보였다. 안정 시 대사량은 D그룹을 제외하고 모든 그룹에서 증가하는 경향을 보였으며 운동과 다이아실글리세롤 섭취에 따라 콜레스테롤의 감소가 일어났다. 추후 카테콜라민, CAMP, HSL, Insulin 등과 같은 지방대사와 관련된 항목들에 대한 추가적인 분석이 이루어짐으로써, DG섭취와 트레이닝의 비만개선효과를 보다 신뢰성 높게 예측할 수 있으리라 본다.