• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 춘계학술대회 논문집 센서 박막재료
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• pp.11-14
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• 2001

We give pressure stimulation into organic thin films and then manufacture a device under the accumulation condition that the state surface pressure is 30[mN/m]. LB layers of Arac. acid deposited by LB method were deposited onto slide glass as Y-type film. The physicochemical properties of the LB films were examined by UV absorption spectrum, SEM and AFM. The structure of manufactured device is Au/arachidic acid/Al. the number of accumulated layers are 3~9. Also. we then examined of the MIM device by means of I-V. The I-V characteristic of the device is measured from -3 to +3[V]. The insulation property of a thin film is better as the distance between electrodes is larger.

• 산업기술연구
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• 제20권A호
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• pp.229-238
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• 2000

Simulation analysis for an auto body manufacturing system has been performed in this study. The major goal is to figure out the condition yielding the production rate, 70 per hour. It is, however, very difficult to maintain this rate due to inherent system factors such as machine failure rates, machine repair rates, number of carriers between manufacturing lines(shops), carrier speed etc. We first carefully examined the system and developed a simulation model using ARENA. We then applied statistical experimental design concepts for performance analysis. Our results indicate that the buffer size of 30 and quick repair of failed robots are required for the desired production rate. Other factors, on the other hand, are seen to have minor effects on the throughput. The approach taken in this study and the results obtained may provide a practical guideline for performance analysis and thus be applied without trepidation for similar cases.

• 소음진동
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• 제11권2호
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• pp.234-240
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• 2001

Recently, the regulations from the government and the concerns of people be raised to the interest in exhaust and intake noise of passenger car as much as other vehicles. In these demands, performance prediction software was developed in this paper. In this study, Robust design was used for improving the noise reduction capacity of intake system with the performance prediction software. On the basis of the existing design, length and radius of each component that was thought to be effective to the performance of intake system was selected. At first, factors are arranged by using Ll8 table of orthogonal array and then optimum value can be obtained by modified Ll6 table of orthogonal array.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.491-494
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• 1999

We have examined the electrical properties of arachidic acid Langmuir (L) films by using a displacement current measuring technique with pressure stimulation. We give pressure stimulation into organic thin films and detect the Induced displacement current. The structure of manufactured device is Au/arachidic acid/Al, the number of accumulated layers are 17, 19 and 21. Also, we then examined of the MIM device by means of I-V The I-V characteristic of the device is measured from 0 to +1[V]. The insulation property of a thin film is better as the distance between electrodes is larger.

• Journal of applied mathematics & informatics
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• 제37권1_2호
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• pp.105-121
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• 2019

One of the main objective of manufacturing industries is to assess the capability performance of different processes. In this paper, we use the lifetime performance index $C_L$ as a criterion to measure larger-the-better type quality characteristic for evaluating the product performance. The lifetimes of products are assumed to follow a general class of inverted exponentiated distributions. We use maximum likelihood estimator to estimate the lifetime performance index under the assumption that data are progressive type I interval censored. We also obtain asymptotic distribution of this estimator. Based on this estimator, a new hypothesis testing procedure is developed with respect to a given lower specification limit. Finally, two numerical examples are discussed in support of the proposed testing procedure.

• 천문학회지
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• 제56권1호
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• pp.41-57
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• 2023

We measured temporal and emission properties of quiescent magnetars using archival Chandra and XMM-Newton data, produced a list of the properties for 17 magnetars, and revisited previously suggested correlations between the properties. Our studies carried out with a larger sample, better spectral characterizations, and more thorough analyses not only confirmed previously-suggested correlations but also found new ones. The observed correlations differ from those seen in other neutron-star populations but generally accord with magnetar models. Specifically, the trends of the intriguing correlations of blackbody luminosity (L_BB) with the spin-inferred dipole magnetic field strength (B_S) and characteristic age (τ_c) were measured to be L_BB ∝ B^1.5_S and L_BB ∝ τ^-0.6_c, supporting the twisted magnetosphere and magnetothermal evolution models for magnetars. We report the analysis results and discuss our findings in the context of magnetar models.

• 한국산업융합학회 논문집
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• 제23권6_1호
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• pp.897-906
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• 2020

This research focuses on the physicochemical characteristic of fermentation of Aloe Saponaria. The fermentation process applied in this study had 2 variation, depends on the aloe part as the materials (bottom, middle, and tip) and the initial sugar content (24% and 0%) used. Tests are conducted using uinkin fermented powder, sugar, salt, and distilled water as fermenting agent. The results indicate that change in physicochemical properties of aloe's skin was larger than in aloe's gel as fermentation materials. In contrast, there was no significant change in aloe's leaf during the process. A lso, aloes with intial sugar condition of 24% show better results than which without sugar addition in fermentation.

• 대한환경공학회지
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• 제22권7호
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• pp.1263-1271
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• 2000

Alum을 이용한 응집 과정에서 탁도 및 유기물 제거와 응집 floc의 특성을 파악하였다. 본 실험에서 구한 탁도 제거영역을 Amitharajah의 연구결과와 비교했을 때 sweep floc 및 charge neutralization의 제거영역이 낮은 pH 영역으로 이동하였는데 그 원인은 원수에 포함된 유기물 농도가 다른데서 찾을 수 있다. 대체적으로 탁도 및 유기물($UV_{254}$와 TOC)의 제거영역은 비슷하였으나 탁도 제거에 비해 낮은 pH에서 유기물 제거의 효과가 높았다. Floc의 특성은 AIA, SALLS 방법을 이용하여 volume diameter과 fractal dimension을 측정하였다. AIA 방법에 비해 SALLS 방법의 측정이 용이하고 신뢰성도 높았다. SALLS 방법을 이용하여 floc을 측정한 결과 sweep floc 영역의 floc이 charge neutralization 영역의 floc 보다 fractal dimension과 평균 직경이 크게 측정되었으며, 오염물질의 제거율이 높을수록 floc의 fractal dimension과 평균 직경도 크게 나타났다.

• 한국전산유체공학회지
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• 제9권4호
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• pp.55-63
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• 2004

The three-dimensional Stokes flow within a staggered screw channel is obtained by using a finite volume method. The geometry is intended to mimic the single screw extruder having staggered arrangement of flights. The flow solution is then subjected to the analysis of the stirring performance. In the analysis of the stirring performance, the stretching-mapping method developed by the author is employed for calculating the materials' stretching exponents, which are to be used in quantification of the mixing effect. The numerical results Indicate that the staggered geometry gives indeed far much better stirring-performance than the standard (nonstaggered) flight geometry. It was also shown that care must be given to the selection of the basis planes for evaluating the local stretching rate, and it turns out that the best method (H-method) has its basis plane just on the half way between the past and future evolution of fluid particles subjected to the defromation. In evaluating the stretching exponent, the expansion ratio must be considered which is one of the characteristic differences of the actual three-dimensional flows from the two-dimensionmal counterparts. The larger axial pressure-difference causes in general the smaller stirring performance while the flow rate is increased. The smaller channel length also increases the stirring performance.

• 패션비즈니스
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• 제11권4호
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• pp.101-110
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• 2007

Since cotton fabrics with ripple finish treatment form wavy furrows on the surface or bumpy patterns, air circulation during wearing is good and the fabric is cool to the touch. The finishing principle is based on the mercerization, which utilizes the fact that cotton fibers contract in a concentrated NaOH solution. In this study, as fabric specimens, cotton fabrics with yarn counts of 40's, 60's and 80's were used. Concentrations of the NaOH solutions were 15%, 25%, and 35%. After dyeing fabrics using Rubia akane nakai, color and other properties were measured. As the concentration of the NaOH solution increased, the fabric became thicker and denser, and the number of occurrence of the prominence and depression per unit length became larger. The color of the region contracted by ripple finish became darker after dyeing, while the color of the untreated region became lighter, which enhanced the cubic effect of the ripple finish. As the count of the cotton yarn increased, the dyeability became better. As the concentration of the NaOH solution increased, the air permeability became lower.