• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.4
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• pp.190-195
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• 2009

Na-tetrasilicic fluorine mica powders were synthesized by skull melting method. The staring materials having chemical composition of $Mg_3(OH)_2Si_4O_{10}:Na_2SiF_6:SiO_2=8.3:24.8:66.9$ mol% were charged into a cold crucible of 13 cm in diameter and 14cm in height and heated by R.F. generator at working frequency of 2.84 MHz. The materials were maintained for 1hr as a molten state and cooled down in the container. In this study, the specific electric resistance of mica was estimated and the columnar and plate shaped mica were synthesized.

• Korean Journal of Social Welfare
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• v.61 no.4
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• pp.287-306
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• 2009

This study examines the effect of children's school satisfaction on academic achievement using the Seoul Children Panel Study data. More specifically, this study aims to add new knowledge to understaning the causal relationship between school satisfaction and academic achievement by taking into account of temporal order of the events of interest. In the analysis, we examine the effect of school satisfaction at the 4th- and 5th- grades on academic achievement at the 6th grade while controlling for the other factors including the level of academic achievement at the 4th grade. The results show that children's school satisfaction significantly affects their academic achievement. The findings of this study have implications for the school social welfare programs that attempt to improve academic achievement of children by raising the level of school satisfaction among children.

• Korean Journal of Optics and Photonics
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• v.5 no.1
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• pp.37-44
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• 1994

The characteristics of stimulated Brillouin scattering wave for applications to high power laser was experimentally investigated. The peak power reflectivity and the phase conjugation fidelity of Stokes wave with respect to the focal length of lens were measured, and the phase conjugation fidelity for a compressed part of the Stokes wave was also investigated. For the long focal length of lens.(f=100 cm), the peak power of the Stokes wave amounts to about twice as high as that of incident wave. The phase conjugation fidelity for the compressed leading pulse is up to 90%, better than that for other temporal parts of the Stokes pulse. In spatial distribution, the Stokes pulse from the axial region has the largest SBS gain, and it has been ascertained as a best candidate to the application due to excellent pulse compression, peak power reflectivity, and good phase conjugation fidelity.

• The Journal of the Korea Contents Association
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• v.10 no.12
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• pp.477-491
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• 2010

This paper aimed to understand current trends in online lectures for Korean SAT based on students' academic performances through a qualitative interview approach. In results, the highest academic performance group showed a good deal of interest and usage in online lectures. This group participants preferred private online lectures to public ones. However, the lowest academic group liked to use public online lectures. The middle academic groups who lived in an expensive area spent a lot of money for tutoring or attending private institutes rather than online lectures. Suggestions are: self-regulated learning is needed, public onilne lectures should have improved contents, and lastly, these online lectures are required to be connected with regular school curriculum.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.675-678
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• 2017

본 논문에서는 스트림 환경에서의 샘플링 기법 중 랜덤 샘플링과 유사한 특성을 갖는 KSample의 균일신뢰도 향상에 초점을 맞춘다. 이를 위해, 먼저 KSample의 균일신뢰도 문제점을 분석하여 KSample의 균일신뢰도가 초기에 많이 감소하는 현상을 초기 균일신뢰도 저하 문제로, KSample의 균일신뢰도가 지속적으로 감소하는 현상을 지속 균일신뢰도 저하 문제라 정의한다. 그리고 초기 균일신뢰도 저하 문제를 발생시키는 성질을 과거 샘플 불변으로, 지속 균일신뢰도 저하 문제를 발생시키는 성질을 샘플 추출 범위 증가로 정의하고 이를 해결하여 균일신뢰도를 향상시킨 UC KSample을 제안한다. 실험 결과, 샘플링 비율 p=0.01, 균일신뢰도 하한 ${\varepsilon}=0.7$일 때, UC KSample의 균일신뢰도가 기존 KSample 보다 약 2.2배 증가하였고, 균일신뢰도는 항상 하한 이상으로 유지되었다. 본 연구는 스트림 환경에서 중요한 척도인 균일신뢰도를 KSample에 결합시킨 최초의 시도로서, 샘플링 비율을 유지하며 동적으로 샘플링하는 KSample의 장점은 유지하면서도 균일신뢰도를 증가시킨 우수한 연구라 사료된다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.3 no.1
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• pp.18-30
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• 1993

A numerical analysis has been carried out on the Czochralski flow fields when uniform and nonuniform magnetic fields are applied. Czochralski flow fields are governed by buoyancy forces, thermocapillarity, centrifugal forces, and applied magneic fields. In this analysis, pressure and three components of velocity vectors are obtained, and circumferential electrical currents are calculated. When a uniform magnetic field is applied, all the velocity components are decreased and the circumferential electric currents near the crystal surface are increased as the magnetic field intensity is increased. In the case of a nonuniform field, the flows in a meridional plane are suppressed and the circumferential velocity is increased as the non uniformity is increased. The understanding on the Czochralski flow fields under the influence of magnetic fields can lead to the study on the behavior of the concentration of the solute and impurities.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.285-285
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• 2020

본 연구에서는 국내 시설농업단지의 수리지질 특성을 고려한 개념 모델을 설정하여 수리전도도와 이격거리(주입정과 양수정 사이의 거리)에 대한 민감도 분석을 수행하였다. 개념 모델에는 자연적 특성(지형과 지질, 강수량, 수리전도도 등)과 인공적 특성(주입정과 양수정의 이격거리, 주입량과 양수량 등)이 입력되었으며, 민감도 분석은 수리전도도(10^-1 cm/sec, 10^-2 cm/sec, 10^-3 cm/sec, 10^-4 cm/sec)와 이격거리(10 m, 50 m, 100 m)를 조합한 12개의 시나리오로 수행하였다. 양수정의 하류부에 설정된 관측정의 지하수위 강하량은 수리전도도가 감소하고 이격거리가 멀어질수록 증가하였다. 동일한 이격거리에서 수리전도도에 의한 지하수위 강하량의 회귀분석을 통해 인공함양 대수층의 지하수위 변동은 수리전도도에 의해 지배적인 영향을 받음을 알 수 있었다. 인공함양 대수층의 수리전도도가 10^-2 cm/sec 이상인 조건에서는 주입정과 양수정의 이격거리에 따른 지하수위의 영향반경은 20 m 이내이었지만, 수리전도도가 10^-3 cm/sec 이하인 조건에서는 이격거리가 멀어질수록 지하수위의 영향반경이 급격하게 증가함을 확인하였다.

• 한국벤처창업학회:학술대회논문집
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• 2023.04a
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• pp.101-116
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• 2023

본 연구는 농산업 예비창업자를 대상으로 자기결정성정도를 조절변수로 하여 창업환경과 창업역량이 창업의도에 미치는 영향을 탐색하였다. 창업환경을 인지된지원과 인지된장벽으로 구분하고 창업역량의 하위변수를 창의성, 문제해결, 의사소통, 마케팅 및 사업계획서를 하위변수로 설정하였다. 수집된 설문지 253부를 실증분석에 사용하였다. SPSS v25.0과 Process macro v4.2를 이용한 분석결과는 첫째, 창업환경의 인지된지원과 인지된장벽은 창업의도에 유의한 영향을 미치고 창업역량의 창의성, 문제해결, 마케팅 및 사업계획서가 창업의도에 미치는 영향은 유의적으로 나타났으나 의사소통이 미치는 영향은 비유의적으로 나타났다. 둘째, 자기결정성정도는 창업환경의 인지돤지원 및 인지된장벽과 농산업 창업의도 간을 조절하지 않는 것으로 나타났다. 이 결과는 자기결정의 수준은 창업 환경과 창업 의도 사이의 관계에는 그다지 큰 영향을 미치지 않음을 의미한다. 셋째, 자기결정성정도는 창업역량의 창의성, 문제해결, 의사소통, 마케팅 및 사업계획서와 창업의도 간을 조절하는 것으로 확인되었다. 구체적으로 자기결정성정도가 커질수록 창의성, 문제해결, 마케팅 및 사업계획서가 창업의도에 미치는 영향력의 크기는 정(+)의 방향으로 강하게 하는 강화작용의 역할을 하는 것으로 나타났다. 반면에 자기결정성정도가 커질수록 의사소통과 창업의도 간의 관계가 약해지는 자기결정성정도가 완화작용을 하는 것으로 나타났다. 후속 연구로는 창업환경과 창업역량을 설명할 수 있는 다른 요인들의 탐색과 새로운 매개변수와 조절변수가 포함된 조건부과정모형을 통해 조절된 매개효과를 분석할 수 있는 후속 연구가 필요할 것으로 보인다.

• Journal of dental hygiene science
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• v.15 no.5
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• pp.666-672
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• 2015

This paper was trying to investigate the periodontal health recognition and self oral hygiene behaviors and figure out that relationship. The results having analyzed 592 questionnaires returned patient who had visited the dental clinic which is selected randomly were following. There were relationships between the periodontal health recognition and self oral hygiene behaviors. Self oral hygiene behaviors were significantly high when, women did than men did, education level, subjective oral health status, and periodontal health recognition about managements were higher and periodontal health recognitions about treatment were lower. It was the periodontal health recognition that was influential the most in the independent variables. Therefore, knowledge related to the periodontal health should be educated to the patients visiting the dental clinic, and the patients should receive helps to perform self oral hygiene behaviors by inducing the transition of attitude to periodontal health.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.5
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• pp.179-184
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• 2018

To lessen oxygen concentrations in a wafer through modifying the length of graphite heaters, we investigated the influence of relative distance from heater to quartz crucible on temperature profile of hot-zone in Czochralski silicon-crystal growth by simulation. In particular, ATC temperature and power profiles as a function of different ingot body positions were investigated for five different heater designs; (a) typical side heater (SH), (b) short side heater-up (SSH-up), (c) short side heater-low (SSH-low), (d) bottom heater without side heater (Only-BH), and (e) side heater with bottom heater (SH + BH). It was confirmed that lower short side heater exhibited the highest ATC temperature, which was attributed to the longest distance from triple point to heater center. In addition, for the viewpoint of energy efficiency, it was observed that the typical side heater showed the lowest power because it heated more area of quartz crucible than that of others. This result provides the possibility to predict the feed-forward delta temperature profile as a function of various heater designs.