• Proceedings of the Membrane Society of Korea Conference
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• 1991.04a
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• pp.38-39
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• 1991

비대칭 다공막은 자체로서 UF혹은 MF용으로 사용될 뿐만 아니라 RO혹은 기체분리용 복합박막의 지지막으로도 사용되기 때문에 비대칭다공막 제조기술은 분리막의 제조에 가장 중요한 것 중의 하나이다. 대부분의 비대칭 다공막은 상반전법에 의하여 제조되며, 상반전법은 균질 고분자용액이 비용매 속에서 두개의 용액상 (고분자 농후 및 희박용액상)으로 분리된 후 비대칭다공막으로 되는 과정을 일컫는다.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.79.1-79.1
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• 2012

Due to the quantum interference of many atomic levels, the exact scattering cross section around a given resonance transition deviates from the Lorentz function when the frequency of the incident radiation is quite far from the resonance frequency. This atomic effect is quite significant in the case of damped Ly alpha systems, where HI column density is in excess of 10^20 cm^-2. In this poster, we present the deviation quantitatively taking into consideration of the Rayleigh and Raman scattering around Lyman alpha and Lyman beta.

• Resources Recycling
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• v.11 no.3
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• pp.17-24
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• 2002

There has been an increasing demand over the years for steels with lower[s] content. For the purpose of improving the efficiency of desulphrization in the powder injection process of ladle, experimental studies were carried out by using cold model to optimize the lance configuration, gas flow rate, immersion depth of lance nozzle, position of lance nozzle relative to the ladle and the effect with slag, etc. As the results of this study, it was made clear that 2-hole nozzle lance (C, E type) placed in an asymmetric position gives the shortest mixing times.

• Journal of the Optical Society of Korea
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• v.6 no.2
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• pp.33-36
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• 2002

We propose a modulation scheme of optical absorption in a coupled asymmetric quantum well (QW) structure via electrically controllable quantum interference. It is based on the parallel-perpendicular energy coupling effect. We show that by applying an external electric Held in the parallel direction (to the QW layers), we can obtain a maximum (peak-type) absorption at a specific wavelength where absorption cancellation would occur due to electrically induced transparency without such an external Held .

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1173-1174
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• 2011

• Environmental and Resource Economics Review
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• v.17 no.4
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• pp.813-843
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• 2008

This paper investigates the presence of long-run and short-run price asymmetries in weekly gasoline prices from January 1997 to July 2008. In accordance with distribution channels, wholesale and retail stages are analyzed separately. An approach based on TAR and M-TAR cointegration tests, which entail matching asymmetric ECMs, is employed. For wholesale prices, asymmetries in the links with crude oil prices and exchange rates are found for both ECMs in the long-run and short-run. Exchange rates appear to play more significant role than crude oil prices in explaining the short-run price asymmetry. The rise in crude oil prices or exchange rates has statistically significant major impact on the increase of wholesale prices on the second week, not immediately as expected in the concept of 'rockets and feathers'. And asymmetrically, the fall does not have any statistically significant effect on the same period. The finding seems to be somewhat unusual. However, for retail prices, asymmetry m connection with wholesale prices is only revealed in the long-run. A symmetric price adjustment can be assumed in the short-run. Contrary to the long-run asymmetry found in the wholesale stage, in the retail stage, the speed of adjustment for negative deviations toward long-run equilibrium is faster than for positive ones, which is a phenomenon not favorable to consumers.

• Management & Information Systems Review
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• v.38 no.3
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• pp.1-19
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• 2019

This paper investigates the asymmetric effects of crude oil price uncertainty on industrial stock returns under different market conditions (bearish and bullish stock markets). We consider a quantile regression method using monthly oil volatility index, KOSPI and 22 industrial stock indices from May 2007 to February 2019. Especially, we take care of the positive and negative changes of the oil volatility index to analyze asymmetric effects of the oil price uncertainty for the bearish and bullish stock market conditions. During the bearish markets, the oil volatility index has relatively strong statistically significant negative effects on the industrial stock returns. These effects gradually decrease when the market conditions became more bullish markets. In particular, positive changes in the oil volatility index yields a further significant decrease in 12 industrial stock returns during the extreme bearish markets. Moreover, during the bullish markets, negative changes in the oil volatility index have statistically significant negative effects on the 12 industrial stock returns. From the empirical results, we see that participants of the Korean stock market are sensitive to bad news in a recession.

• Industrial Engineering and Management Systems
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• v.12 no.2
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• pp.95-102
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• 2013

It is difficult to determine an appropriate discount price for daily perishable products to increase profit from a long-term standpoint. Even if the discount pricing is efficient to increase profit of the day, consumers memorize the sales price and they might hesitate to purchase the product at a regular price the following day. The authors discussed the inventory clearance pricing for a single period in our previous study by constructing a mathematical model to derive an optimal sales price to maximize the expected profit by considering the reference price effect of demand. This paper extends the discussion to handle the discount pricing for multiple periods. A mathematical analysis is first conducted to reveal the properties on an objective function, which is the present value of total expected profits for multiple periods. An algorithm is then proposed to derive an optimal price for asymmetric consumers. Numerical experiments investigate the characteristics of the objective function and optimal pricings.

• Korea Trade Review
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• v.47 no.4
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• pp.35-52
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• 2022

Air transport is at the core of global economic growth. There is a close relationship between the flow of regional elements and the growth of the regional economy. It is easy to misestimate the impact of airports on the regional economy without considering spatial spillover effects. This study attempted to establish an asymmetric economic geographical weight matrix by applying the Spatial Durbin Model with cargo volume and passenger numbers as indicators. The influence of spillover effects on the regional economy, including direct spillover effects and indirect spillover effects are studied. The results revealed that passenger numbers and cargo volume have significant positive spillover effects on the regional economy. The driving effect of the airport on the regional economy was considered from a wider space scope. This study contributes to the scientific evaluation of the aviation economy.

• Radiation Oncology Journal
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• v.7 no.2
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• pp.305-311
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• 1989

Fletcher-Suit colpostat has an internal structure to reduce dose to bladder and rectum. Some programs were developed to calculate dose at any point in water in three dimension around the colpostat containing Cs-137 tube, to find the shielding effect to dose by the internal structure, and to draw isodose curves and iso-shielding effect curves. Computer was an IBM compatible AT with EGA card and language was MS-Basic V6.0, Material, shape and geometry of the strucure, tube and colpostat were considered in algorithm for calculation of dose. Dose rates per unit mg. Ra. eq. in water calculated by a program were stored in auxiliary memory devices and retrieved in another programs. Isodose curves on medial side shrinked. Dose distribution was not symmetric about a transverse axis bisecting the colpostat. Reduction of dose was more excessive on top side than on bottom. Iso-shielding effect curve showed that the shielding effect was higher on top side than on bottom, and that there was shielding effect over almost all area of medial side. Such results were related to both shifted position of tube in the colpostat and asymmetric distribution of active source in the tube. Maximum of shielding effect was $49\%$ on top side and $44\%$ on bottom side. The direction of iso-shielding effect curve was generally radial from the center of active source. In treatment planning using Fletcher-Suit colpostat, the internal structure should be considered to find precise doses to bladder and rectum, etc.