• 대한원격탐사학회지
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• 제11권2호
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• pp.29-42
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• 1995

A typhoon center location and its intensity from the 54.96GMz channel of Microwave Sounding Unit(MSU) on board the NOAA satellite is analyzed. NOAA satellite MSU channel 3 data may delineate the development and dissipation of the upper tropospheric warm core associated with a typhoon. The typhoon warm core is related to microwave imagery of 250hPa temperature field (54.96GMz). The typhoon center intensity, surface center pressure and maximum wind speed at the eye well, correlate to horozontal Laplacian of an upper tropospheric temperature field. The typhoon center is found from the analysis of 250hPa temperature field. The excellent correlation is found between the horizontal Laplacian of an tropospheric temperature field and surface maximum wind speed, another correlation is found between the warm temperature anomaly and surface pressure anomaly.

• Bulletin of the Korean Chemical Society
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• 제21권1호
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• pp.69-74
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• 2000

Applicability of Thermal field flow fractionation (ThFFF) was investigated for the analysis of masticated natural rubber (NR) adhesives produced bya hot melt mastication process. An optimum ThFFF condition for NR analysis was found by using tetrahydrofuran (THF) as a solvent/carrier and a field-programming. Low flowrate (0.3 mL/min) was used to avoid stopping the flow for the sample relaxation. Measured molecular weight distribution was used to monitor degradation of rubber during the mastication process. Rubber samples collected at three different stages of the mastication process and were analyzed by ThFFF. It was found that in an anaerobic process rubber degradation occurs at the resin-mixing (compounding) zone as well as in the initial break-down zone, while in an aerobic process most of degradation occurs at the initial breakdown zone. It was also found that E-beam radiation on NR causes a slight increase in the NR molecular weight due to the formation of a branched structure.

• 대한치과기공학회지
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• 제44권3호
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• pp.81-88
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• 2022

Purpose: This study was conducted to verify the effects of self-esteem and critical thinking disposition on dental laboratory technology students' field practice stress. Methods: The subjects of the study were 198 dental laboratory technology students with clinical practice experience located in Gyeongsangbuk-do and Gyeongsangnam-do. The collected data were analyzed by t-test, ANOVA, correlation analysis, and linear regression analysis using IBM SPSS Statistics ver. 22.0 (IBM). Results: The average self-esteem, critical thinking disposition, and field practice stress scores were 3.76, 3.50, and 2.40, respectively. There was a significant correlation between self-esteem, critical thinking disposition, and field practice stress. It was found that the higher the self-esteem, the lower was the field practice stress. On the contrary, among the sub-items of critical thinking disposition, when intellectual fairness increased, the field practice stress decreased; however, when healthy skepticism increased, the field practice stress increased. Conclusion: Self-esteem and critical thinking disposition were both found to have a substantial effect on field practice stress. Therefore, various educational programs need to increase self-esteem and cultivate critical thinking skills for a successful field practice and field practice stress relief of laboratory technology students.

• Journal of Magnetics
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• 제22권1호
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• pp.1-6
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• 2017

Magnetic properties of CoPt nanoparticles (average size = 2.1 nm) encapsulated in synthesized protein shell have been investigated with SQUID (Superconducting Quantum Interference Device) magnetometer and analyzed by the recently developed non-equilibrium magnetization calculation by our group [T. H. Lee et al., Phys. Rev. B 90, 184411 (2014)]. Field dependence of magnetization measured at 2 K was successfully analyzed with modified Langevin function. In addition, small hysteresis loops having the coercive field of 890 Oe were observed at 2 K. Temperature dependence of magnetization has been measured with zero field cooled (ZFC) and field cooled (FC) protocol with slightly modified sequence in accordance with non-equilibrium magnetization calculation. The analysis on the M vs. T data revealed that the anisotropy energy barrier distribution is found to be very different from the log-normal distribution found in a size distribution. Zero temperature coercive field and Bloch coefficient have also been extracted from the analysis and the validity of those values is checked.

• 한국도로학회논문집
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• 제17권1호
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• pp.51-58
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• 2015

PURPOSES : The objective of this study is to compare the densities of asphalt pavements measured both in the field and in the laboratory, and also to evaluate the applicability of field density measuring equipment, such as the pavement quality indicator (PQI), by using statistical analysis. METHODS : For the statistical analysis of the density measured from asphalt pavement, student t-tests and a coefficient of correlation are investigated. In order to compare the measured densities, two test sections are prepared, with a base layer and an intermediate layer constructed. Each test section consists of 9 smaller sections. During construction, the field densities are measured for both layers (base and intermediate) in each section. Core samples are extracted from similar regions in each section, and moved to the laboratory for density measurements. All the measured densities from both the field and laboratory observations are analyzed using the selected statistical analysis methods. RESULTS AND CONCLUSION : Based on an analysis of measured densities, analysis using a correlation coefficient is found to be more accurate than analysis using a student t-test. The correlation coefficient (R) between the field density and the core density is found to be very low with a confidence interval less than 0.5. This may be the result of inappropriate calibration of the measuring equipment. Additionally, the correlation coefficient for the base layer is higher than for the intermediate layer. Finally, we observe that prior to using the density measuring equipment in the field, a calibration process should be performed to ensure the reliability of measured field densities.

• 대한기계학회논문집A
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• 제21권11호
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• pp.1844-1851
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• 1997

Displacement fields and interface stresses are obtained by modifying the potential energy functional with a penalty function which enforces the continuity of stresses at the interface of two-materials. Based on the displacement field and the interface stresses, a new methodology to generate a continuous stress field over the entire domain including the interface of the dissimilar materials has been proposed by combining the L$^{2}$ projection method of stress-smoothing and the Loubignac's iterative method of improving the displacement field. Stress analysis was carried out on two examples which are made of highly dissimilar materials. As a result of the analysis, it is found that the proposed method provides improved continuity of the stress field over the entire domain as well as predicting accurate nodal stresses at the interface. In contrast, the conventional displacement-based finite element method provides significant stress discontinuties at the interfaces. In addition, it was found that the total strain energy evaluated from the improved continuous stress field converge to the exact value as increasing the number of iterations in the proposed method.

• 대한공업교육학회지
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• 제40권1호
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• pp.142-162
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• 2015

본 연구는 전기공사 현장대리인의 역할 및 역량을 도출하고, 현업에 있는 현장대리인의 교육 요구도를 확인하여 향후 국내기업에서 현장대리인이 성공적인 역할을 수행하기 위한 기초자료와 시사점을 제공하는데 그 목적이 있다. 연구목적을 달성하기 위해 (1) 전기공사 현장대리인의 역할 분석, (2) 전기공사 현장대리인의 역량 분석, (3) 전기공사 현장대리인의 역량에 대한 교육 요구분석의 3단계로 연구절차를 설정하였다. 연구방법은 전기공사 현장대리인 전문가 10명에 대한 포커스그룹 인터뷰를 수행하였고, 현업에 종사하고 있는 현장대리인을 대상으로 설문조사를 실시하였다. 요구분석은 현장대리인의 종요도와 현재 수준 간의 차이를 t 검정으로 분석하고, 역량 중요도와 현재수준에 대한 인식차이를 Borich 공식을 활용하여 도출하였으며, The Locus for Focus 모델을 통해 역량 중요도가 높고 불일치수준이 높은 역량을 확인하여 우선순위를 결정하였다. 본 연구의 결과는 다음과 같다. 첫째, 전기공사 현장대리인의 역할은 현장조사자, 서류작성자, 대관업무자 등 13개가 도출되었다. 둘째, 전기공사 현장대리인의 역량은 의사소통능력, 협력적 태도 등 총 16개 역량이 필요한 것으로 도출되었다. 현장대리인의 중요도 인식순위는 의사결정력, 의사소통능력, 실천력, 시간관리능력, 분석적사고 순으로 높게 나타났다. 셋째, 16개의 역량에 대한 현재수준과 중요도의 차이를 분석한 결과 통계적으로 모두 유의미한 차이를 보이고 있고, Borich 요구도 분석 결과 1순위로 요구되는 역량은 '의사소통능력'이었고, '실천력', '갈등관리능력', '분석적사고', '시간관리능력' 순이었다. 또한, The Locus for Focus 모델 분석 결과 제 1사분면(HH)에 포함된 역량은 '의사소통능력', '분석적사고', '의사결정력', '전문성', '시간관리능력', '실천력', '업무추진력'으로 7개 역량에 요구가 높은 것으로 나타났다. 이에 최우선 순위군은 Borich 요구도와 The Locus for Focus 모델에서 공통적으로 나타난 '의사소통능력', '분석적사고', '시간관리능력', '실천력', '업무추진력' 5개 항목이었고, '의사결정력', '전문성', '갈등관리능력', '부하육성' 4개 항목은 차순위 군으로 분석되었다.

• 전기전자학회논문지
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• 제22권1호
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• pp.61-67
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• 2018

We investigated theoretically the magnetic field dependence of the quantum optical transition of qusi 2-Dimensional Landau splitting system, in CdS and ZnO. In this study, we investigate electron confinement by square well confinement potential in magnetic field system using quantum transport theory(QTR). In this study, theoretical formulas for numerical analysis are derived using Liouville equation method and Equilibrium Average Projection Scheme (EAPS). In this study, the absorption power, P (B), and the Quantum Transition Line Widths (QTLWS) of the magnetic field in CdS and ZnO can be deduced from the numerical analysis of the theoretical equations, and the optical quantum transition line shape (QTLS) is found to increase. We also found that QTLW, ${\gamma}(B)_{total}$ of CdS < ${\gamma}(B)_{total}$ of ZnO in the magnetic field region B<25 Tesla.

• 한국초전도ㆍ저온공학회논문지
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• 제17권3호
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• pp.23-27
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• 2015

Quadruple magnet is an essential component for the accelerator, and the field uniformity in the good field region reflects the quality of quadruple magnet. In this paper, the total magnetic field B was separated into the coil-induced magnetic field $B_s$ and the iron-induced magnetic field $B_c$ to explain why the total magnetic field B has some inhomogeneity. Using Fourier analysis, harmonic components of $B_s$, $B_c$ and B have been analyzed at good field region, respectively. The harmonics of multipole magnet and Fourier analysis are helpful to show the uniformity of magnetic field. Several geometries of yoke and coils were defined to analyze the effect on field uniformity of an HTS quadruple magnet. By the analysis, it was found that the sixth harmonics which is the main factor of field inhomogeneity can be reduced to zero. It means that the sixth harmonics of the magnetic field B can be removed by adjusting the geometry of the magnet pole and the position of coils. We expect that this result can effectively improve the uniformity of an HTS quadruple magnet.

• Journal of Mechanical Science and Technology
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• 제20권9호
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• pp.1514-1524
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• 2006

This work presents the three-dimensional analysis of flow and heat transfer performed for a wire-wrapped fuel assembly of liquid metal reactor using Reynolds-averaged Wavier-Stokes analysis in conjunction with 557 model as a turbulence closure. The whole fuel assembly has been analyzed for one period of the wire-spacer using periodic boundary conditions at inlet and outlet of the calculation domain. Three different assemblies, two 7-pin wire-spacer fuel assemblies and one bare rod bundle, apart from the pressure drop calculations for a 19-pin case, have been analyzed. Individual as well as a comparative analysis of the flow field and heat transfer have been discussed. Also, discussed is the position of hot spots observed in the wire-spacer fuel assembly. The flow field in the subchannels of a bare rod bundle and a wire-spacer fuel assembly is found to be different. A directional temperature gradient is found to exist in the subchannels of a wire-spacer fuel assembly Local Nusselt number in the subchannels of wire-spacer fuel assemblies is found to vary according to the wire-wrap position while in case of bare rod bundle, it's found to be constant.