• 대한기계학회논문집B
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• 제22권4호
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• pp.468-480
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• 1998

The temporal and spatial distributions of soot volume fractions were measured for single toluene droplet flames as a function of pressure under the normal-gravity condition. In order to characterize the transient nature of the flame and sooting regions, a full-field light extinction and subsequent tomographic inversion technique was used. The reduction in sooting as a function of pressure was assessed by comparison of the maximum soot volume fractions at several vertical positions along the axis above the droplet. The maximum soot volume fraction was reduced by 70% when the pressure was reduced by 60% from 1 atm to 0.4 atm. The reduction in sooting is attributed to variation of the geometric configuration of flame which reduces the system Grashof number as well as only the change in the adiabatic flame temperature as the pressure decreases. The gravimetrically-measured total soot yield was also compared to the optically-measured soot volume fraction to obtain a correlation between the two measurements. As a result, the total soot yield was linearly proportional to the optically-measured maximum soot volume fraction and linearly reduced as the pressure decreased. Accordingly, the non-intrusive full-field light extinction-measurements were able to be calibrated not only to measure soot volume fraction, but to simultaneously evaluate the total soot yield emitted from the toluene droplet flame (which is useful in the practical application).

• Animal Bioscience
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• 제36권9호
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• pp.1376-1383
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• 2023

Objective: We aimed to determine the effects of 12-oxoeicosatetraenoic acid (12-KETE)-induced placenta release on the performance of mother cows (milk yield, ovarian function, and blood plasma biochemical properties). Methods: Experimental treatments were as follows: i) natural delivery including natural placental release (control cows); ii) induced calf delivery with placental retention (RP cows); and iii) induced calf delivery and 12-KETE-induced placental release (KE cows). Delivery in pregnant KE cows was induced with dexamethasone and prostaglandin. These cows were injected with 12-KETE after calf discharge, resulting in the release of the fetal placenta. RP cows were not treated with 12-KETE after inducing delivery, resulting in placental retention. Results: The milk yield in RP cows during the first 50 days after delivery was significantly lower than that in control cows (p<0.05), whereas KE cows exhibited a similar milk yield to that of control cows. The postpartum plasma progesterone levels of control cows increased 14 days after delivery on average; however, its increase was delayed by 10 days in RP cows. Meanwhile, the 12-KETE treatment (KE cows) brought the timing of progesterone increase forward to the normal level (control cows). Among the 20 biochemical parameters examined, the total cholesterol levels in blood plasma 14 days after delivery were lower in RP cows than that in the other two treatment groups (control cows and KE cows) (p<0.05). In addition, the plasma level of haptoglobin tended to be low in cows that discharged their placentas shortly after delivery. Conclusion: These findings indicate that 12-KETE treatment can alleviate the disorder caused by placental retention.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.295-295
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• 2016

Recently, TCO films with low carrier concentration, high mobility and high work function are proposed beneficial as front electrode in HIT solar cell due to free-carrier absorption in NIR wavelength region and low Schottky barrier height in the front TCO/a-Si:H(p) interface. We report high transmittance and work function zirconium-doped indium tin oxide (ITO:Zr) films with various plasma (Ar/O2 and Ar) conditions. The role of (Ar/O2) plasma was to enhance the work function of the ITO:Zr films whereas the pure Ar plasma based ITO:Zr showed good electrical properties. The RF magnetron sputtered ITO:Zr films with low resistivity and high transmittance were employed as front electrode in HIT solar cells, yield the best performance of 18.15% with an open-circuit voltage of 710 eV and current density of 34.63 mA/cm2. The high work function ITO:Zr films can be used to modify the front barrier height of HIT solar cell.

• Wind and Structures
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• 제17권4호
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• pp.361-377
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• 2013

Wall functions have been widely used in computational fluid dynamics (CFD) simulations and can save significant computational costs compared to other near-wall flow treatment strategies. However, most of the existing wall functions were based on the asymptotic characteristics of near-wall flow quantities, which are inapplicable in complex and non-equilibrium flows. A modified wall function is thus derived in this study based on flow over a plate at zero-pressure gradient, instead of on the basis of asymptotic formulations. Turbulent kinetic energy generation ($G_P$), dissipation rate (${\varepsilon}$) and shear stress (${\tau}_{\omega}$) are composed together as the near-wall expressions. Performances of the modified wall function combined with the nonlinear realizable k-${\varepsilon}$ turbulence model are investigated in homogeneous equilibrium atmosphere boundary layer (ABL) and flow around a 6 m cube. The computational results and associated comparisons to available full-scale measurements show a clear improvement over the standard wall function, especially in reproducing the boundary layer flow. It is demonstrated through the two case studies that the modified wall function is indeed adaptive and can yield accurate prediction results, in spite of its simplicity.

• 한국광학회지
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• 제15권2호
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• pp.149-157
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• 2004

문턱 전류 이상에서 complex-coupled(CC) DFB 레이저의 여러 가지 ｜$\chi$L｜과 양 단면 반사율 조합에 대하여 파워 추출 효율과 발진 파장 분포를 구하였고 문턱 전류에서의 결과와 비교하였다. 또한 결함 계수 비(CR)와 Ar 단면의 반사율이 파워 추출 효율과 발진 파장 분포에 미치는 영향에 대하여 살펴보았다. 문턱 전류에서 in-phase(IP) CC DFB 레이저와 anti-phase(AP) CC DFB 레이저의 파워 추출 효율에 대하여 도시한 단일 모드 수율은 정확히 일치하였다. 그러나 문턱 전류 이상에서는 IP CC DFB 레이저의 파워 추출에 대하여 도시한 단일 모드 수율은 AP CC DFB 레이저보다 크게 나타났다. IP CC DFB 레이저의 경우 양 단면 반사율 조합이 AR-HR의 경우가 다른 반사율 조합에 비해 단일 모드 수율이 크고 또한 파워 추출 효율이 큼을 알 수 있었다. 본 논문에서 고려한 경우 중에서 ｜$\chi$L｜이 0.8이고 AR-HR인 경우가 문턱 전류 이상에서 단일 모드 수율과 파워 추출 효율이 가장 컸다. 양 단면 반사율 조합이 AR-HR인 경우 CR이 커질수록, AR단면의 반사율이 작아질수록 spatial hole burning 현상이 완화되어 단일 모드 수율과 파워 추출 효율이 커졌다. 양 단면 반사율 조합이 AR-HR인 경우 CC DFB 레이저의 발진 파장은 DFB 금지 대역 내에 넓게 분포하였다. CR이 증가할수록 IP CC DFB 레이저는 장파장 모드에, AP CC DFB 레이저는 단파장 모드에 발진 파장 분포가 증가하였다. ｜$\chi$L｜이 커질수록 발진 파장이 존재하는 파장 폭이 작아 지고 발진 파장 분포가 장파장 쪽으로 이동하였다.

• 대한수학회논문집
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• 제32권3호
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• pp.601-617
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• 2017

We give a function associated with generalized Ostrowski type inequality and its integral representation for local fractional calculus. Then, using this function and its integral representation, we establish several inequalities of generalized Ostrowski type for twice local fractional differentiable functions. We also consider some special cases of the main results which are further applied to a concrete function to yield two interesting inequalities associated with two generalized means.

• 수산경영론집
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• 제51권1호
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• pp.19-36
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• 2020

The purpose of this paper is to analyze the productivity of the costal fisheries in Jeonnam Province. In this study, the operational characteristics and Cobb-Douglas production function of coastal fisheries were examined based on a research on the actual condition of costal fisheries (RACF). The statistical analysis of RACF data reveals that Cobb-Douglas production function consists of the three variables: fishing quantity per ton-age, the number of fisherman per ton-age and fishing equipment cost per ton-age. The results of this study show us that the relation and productivity between labor and capital of the operational equipment in the coastal fisheries. If extensive comparable biological and market data become available, analysis model can be widely applied to yield more accurate results.

• 한국전기전자재료학회논문지
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• 제17권6호
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• pp.602-607
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• 2004

This paper describes the characteristics of Ru-Zr alloy gate electrodes deposited by co-sputtering. The various atomic composition was made possible by controlling sputtering power of Ru and Zr. Thermal stability was examined through 600 and 700 $^{\circ}C$ RTA annealing. Variation of oxide thickness and X-ray diffraction(XRD) pattern after annealing were employed to determine the reaction at interface. Low and relatively stable sheet resistances were observed for Ru-Zr alloy after annealing. Electrical properties of alloy film were measured from MOS capacitor and specific atomic composition of Zr and Ru was found to yield compatible work function for nMOS. Ru-Zr alloy was stable up to $700^{\circ}C$ while maintaining appropriate work function and oxide thickness.

• 한국광학회지
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• 제14권5호
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• pp.521-529
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• 2003

Complex-coupled(CC) DFB 레이저의 경우 문턱 전류에서 spatial hole burning (SHB)현상을 나타내는 f 계수를 고려하여 구한 단일 모드 수율과 문턱 전류 이상에서의 단일 모드 수율과의 연관성이 존재하지 않음을 알 수 있었다. 문턱 전류에서 f 계수를 고려하여 구한 in-phase (IP) CC DFB 레이저와 anti-phase (AP) CC DFB 레이저의 단일 모드 수율은 일치하였으나 문턱 전류 이상에서는 큰 차이를 보였다. 문턱 전류 이상에서 IP CC DFB 레이저의 단일 모드 수율은 결합 계수 비가 증가할수록 증가하였다 반면에 AP CC DFB 레이저의 경우 결합 계수 비에 관계없이 주입 전류가 증가하면 단일 모드 수율은 급격히 감소함을 알 수 있었다. 양 단면 반사율 조합이 AR-HR인 경우 결합 세기가 작을수록 AR 단면의 반사율이 단일 모드 수율에 미치는 영향이 크게 나타났다. 결합 세기가 작을수록 단일 모드 수율의 증가율이 완만해지기 시작하는 결합 계수 비가 커졌고 또한 최대 단일 모드 수율이 증가하였다 양 단면 반사율 조합이 AR-HR과 AR-AR의 경우가 AR-CL과 CL-CL인 경우에 비하여 단일 모드 수율이 크게 나타났다.

• 한국지반공학회논문집
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• 제21권4호
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• pp.31-40
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• 2005

본 연구에서는 이방성을 가지는 현장지반의 비배수 전단거동을 예측하기 위해 한계상태 간격비를 고려한 새로운 항복함수식을 제안하였다. 또한 수정 Cam-clay모델의 항복면 식을 이방압밀 조건에 적용할 수 있도록 수정한 새로운 소성포텐셜 함수를 적용하는 비관련 구성모델을 제안하였다. 제안모델을 적용하여 등방 및 이방압밀된 재성형 포항 이암풍화토의 비배수 전단거동을 예측하였으며, 신뢰성을 평가하기 위해 등방정규압밀된 Bankok clay 및 $K_0$ 압밀된 Drammen clay의 비배수 전단거동을 예측하였다. 그 결과 제안된 모델은 전반적인 거동을 잘 예측하는 것으로 나타났다.