• 한국막학회:학술대회논문집
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• 한국막학회 1998년도 추계 총회 및 학술발표회
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• pp.11-14
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• 1998

1. Introduction : Research progresses in Chemistry and Chemical Engineering have been made during the last decades with important contributions to the industrial development and to the quality of our life. An interesting case is related to the membrane science and technology continuous impact to innovative processes and products, particularly appropriate for a sustainable industrial growth. Membrane operations have been familiar for many years to biologists and chemists working in their laboratorier or studying biological phenomena. Only recently engineers started to operate in' this area. The preparation of asymmetric CA membranes at University of California, Los Angeles in the early 60s is generally recognized as a crucial moment for membranology (1). Loeb and Sourirajan with their discovery of how to increase significantly the permeability of polymeric membranes without significant changes in their selectivity, made realistic the possibility of their use in large scale operations for desalting brackish and sea water by reverse osmosis and for various other molecular separations in different industrial areas. Reverse osmosis is today a well recognized basic unit operations, togheter with ultrafiltration, crossflow microfiltration,. nanofiltration, all pressure driven membrane processes. Already in 1992 more than 4 milIions m$^3$/day were the total capacity of RO desalination plants and in 1995 more than 180.000 m$^2$ of ultrafiltration membranes were installed for the treatment of wheys and milk (2) (3).

• 자원환경지질
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• 제23권4호
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• pp.453-463
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• 1990

주향이동운동(走向移動運動)에 의해 발달된 예천(醴泉) 전단대(剪斷帶)는 쥬라기 구조운동(構造運動)과 동시(同時)에 화강암류(花崗岩類)가 정치(定置)된 후，비교적 고온상태(高溫狀態)에서 생성(生成)되었다. 전단대(剪斷帶)가 화강암류(花崗岩類) 정치(定置)후 발달(發達)하였음은 화강암체(花崗岩體) 내외(內外)에서 엽리(葉理)와 선구조(線構造)의 운결성(運結性), 분쇄질(粉碎質) 구조(構造)의 발달(發達)，페그마타이트와 규장암맥(硅長岩脈)의 변형작용(變形作用)，모암(母岩)에서 반장변정(班狀變晶)들의 구조전(構造前)(Pretectonic)성장(成長) 등에 의해 확인된다. 전단대(剪斷帶)의 다양한 전단감각(剪斷感覺) 지시자(指時者)들은 대부분 전단대(剪斷帶) 중심부(中心部)의 강변형암(强變形岩)에서 잘 관찰된다. 이들은 전단감각(剪斷感覺)이 S-C fabric, 형태(形態) 선택배향(選擇配向)，비대칭(非對稱) Porphyroclast system, Mica fish, 비대칭(非對稱) 신장구조(伸張構造)，결정축(結晶軸) 선택배향(選擇配向)둥에 의해 일관성(一貫性) 있게 우수향(右手向)(Dextral)임을 보여준다.

• 국제지역연구
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• 제18권3호
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• pp.67-88
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• 2014

본 연구에서는 중국시장을 중심으로 수익률 전이현상(return spillover effect) 및 변동성 전이현상(volatility spillover effect)을 이변량 VAR-EGARCH 모형을 이용하여 실증 분석하였다. 그리고 최근의 글로벌 금융위기를 중심으로 금융위기 이전과 이후로 나누어서 전이효과를 실증 분석하였다. 실증분석 결과, 전체기간에서 중국으로부터 일본 만이 수익률 전이현상을 가지고 있었고 변동성 전이현상은 미국뿐만 아니라 일본, 한국에게도 모두 영향을 주었다. 기간을 나누어서 분석한 결과, 금융위기 전에는 일본과 한국에게 수익률 전이현상을 가지고 있었고 금융위기 후 그 크기가 상대적으로 증가한 것으로 나타났다. 또한, 중국의 변동성 전이현상도 한국에게 영향을 주고 미국으로부터 영향을 받다가, 금융위기 후 한국을 제외한 미국과 일본은 중국과 양방향의 관계를 가지고 있었고 그 크기가 증가하였다. 하지만 미국으로부터 중국으로의 변동성 전이현상은 감소하는 것으로 나타났다. 이는 글로벌 금융위기 이후 중국시장의 영향력이 증대되고 있음을 의미한다.

• Journal of Korean Neurosurgical Society
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• 제66권4호
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• pp.382-392
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• 2023

Objective : The use of indocyanine green videoangiography (ICG-VA) to assess blood flow in the brain during cerebrovascular surgery has been increasing. Clinical studies on ICG-VA have predominantly focused on qualitative analysis. However, quantitative analysis numerical modelling for time profiling enables a more accurate evaluation of blood flow kinetics. In this study, we established a multiple exponential modified Gaussian (multi-EMG) model for quantitative ICG-VA to understand accurately the status of cerebral hemodynamics. Methods : We obtained clinical data of cerebral blood flow acquired the quantitative analysis ICG-VA during cerebrovascular surgery. Varied asymmetric peak functions were compared to find the most matching function form with clinical data by using a nonlinear regression algorithm. To verify the result of the nonlinear regression, the mode function was applied to various types of data. Results : The proposed multi-EMG model is well fitted to the clinical data. Because the primary parameters-growth and decay rates, and peak center and heights-of the model are characteristics of model function, they provide accurate reference values for assessing cerebral hemodynamics in various conditions. In addition, the primary parameters can be estimated on the curves with partially missed data. The accuracy of the model estimation was verified by a repeated curve fitting method using manipulation of missing data. Conclusion : The multi-EMG model can possibly serve as a universal model for cerebral hemodynamics in a comparison with other asymmetric peak functions. According to the results, the model can be helpful for clinical research assessment of cerebrovascular hemodynamics in a clinical setting.

• BMB Reports
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• 제51권11호
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• pp.547-548
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• 2018

Phloem network integrates cellular energy status into post-embryonic growth, and development by tight regulation of carbon allocation. Phloem development involves complicated coordination of cell fate determination, cell division, and terminal differentiation into sieve elements (SEs), functional conduit. All of these processes must be tightly coordinated, for optimization of systemic connection between source supplies and sink demands throughout plant life cycle, that has substantial impact on crop productivity. Despite its pivotal role, surprisingly, regulatory mechanisms underlying phloem development have just begun to be explored, and we recently identified a novel translational regulatory network involving RNA G-quadruplex and a zinc-finger protein, JULGI, for phloem development. From this perspective, we further discuss the role of RNA G-quadruplex on post-transcriptional control of phloem regulators, as a potential interface integrating spatial information for asymmetric cell division, and phloem development.

• 한국막학회:학술대회논문집
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• 한국막학회 1991년도 추계 총회 및 학술발표회
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• pp.34-35
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• 1991

비대칭 다공막은 표피와 다공층으로 되어 있는 것으로 알려져 왔으나 (그림 1-a), 최근에 두 층 사이에 nodule층의 존재가 여러 연구자들에 의하여 알려졌다. (그림 1-b). 그런데 표피층은 겔화에 의해 그리고 다공층은 binodal에 의한 nucleation and growth 기구로 생성된다는 것이 일반화된 이론이나, nodule 층의 생성에 대한 연구는 없었다. Nodule층의 생성기구를 밝히기 위해서 고분자용액을 편의상 세개의 층으로 나누었으며 (그림 2), 알려진 생성 기구에 의하면 첫째 층은 표피 그리고 셋째는 다공층으로 된다. 그런데 둘째층은 상분리 순간의 고분자 농도에 따라 nodule층 혹은 다공층이 되며, 만일 이 순간의 고분자농도가 임계농도 보다 낮으면 nodule층 그리고 높으면 다공층이 생성된다는 새로운 비대칭 다공막의 생성기구를 제안하였다. (그림 3).

• 한국기술혁신학회:학술대회논문집
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• 한국기술혁신학회 2001년도 춘계학술대회:발표자료
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• pp.41-58
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• 2001

The growth of fixed telephony has been steady but unexceptional. The number of mobile telephone subscribers, however, has increased dramatically throughout the decade. The increasing prevalence of mobile communications, in conjunction with the relatively high penetration of fixed telephony, will cause the market for converged services to become significant in coming decade. The current fixed and mobile regulatory regimes are very different. Regulation of the fixed market tends to focus on monitoring the activities of incumbent operator and ensuring that other operators can compete on a fair basis. Mobile markets have historically been more competitive, and the asymmetric nature of regulation of these markets has not been as prevalent as for fixed communications. The purpose of this paper is to identify the fixed-mobile convergence and to suggest the future regulatory principles for fixed-mobile convergence.

• Advanced Composite Materials
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• 제17권3호
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• pp.301-317
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• 2008

The energy release rate associated with crack growth in adhesive double cantilever beam (DCB) specimens, including the effect of residual stresses, was formulated using beam theory. Because of the rotation of the asymmetric arms in the adhesive DCB specimens due to temperature change, it is necessary to correct the evaluated fracture toughness of the DCB specimens, specifically in the case of a large temperature change. This study shows that the difference between the true toughness and an apparent toughness due to the consequence of ignoring residual stresses can be calculated for a given specimen geometry and thermo-mechanical properties (e.g. coefficient of thermal expansion). The calculated difference in the energy release rates based on the present correction method is compared with that from FEM in order to verify the present correction method. The residual stress effects on the evaluation of the adhesive fracture toughness are discussed.

• 한국막학회:학술대회논문집
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• 한국막학회 2004년도 Proceedings of the second conference of aseanian membrane society
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• pp.74-77
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• 2004

Porous membranes were prepared via thermally induced phase separation (TIPS) of (ethylene-co-vinyl alcohol) (EVOH)/glycerol mixtures. The liquid-liquid (L-L) phase boundaries are shifted to higher temperature when the ethylene contents in EVOH increase. Moreover, the kinetic study proved that the growth of droplets formed by the general liquid-liquid (L-L) phase separation obeyed a power-law scaling relationship in the later stage of spinodal decomposition (SD). A new phase separation mechanism was presented, in which the L-L phase separation could be resulted from the crystallization. The hollow fiber membranes were prepared. The membranes showed asymmetric structures with skin layer near the outer surface, the larger pores just below the skin layer and the smaller pores near the inner surface. The effect of ethylene content (EC) in EVOH, cooling water bath temperature and take-up speed on membrane performance was investigated.

• East Asian Economic Review
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• 제22권4호
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• pp.427-465
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• 2018

East Asia, for long the epitome of successful engagement in trade, faces serious challenges: technological change that may threaten the very model of labor intensive industrialization and a backlash against globalization that may reduce access to important markets. The analysis in this article suggests that how East Asia copes with these global challenges will depend on how it addresses three more proximate national and regional challenges. The first is the emergence of China as a global trade giant, which is fundamentally altering the trading patterns and opportunities of its neighbors. The second is the asymmetric implementation of national reform - in goods trade and investment versus services - which is affecting the evolution of comparative advantage and productivity in each country. The third is the divergence between the relatively shallow and fragmented agreements that regulate the region's trade and investment and the growing importance of regional and global value chains as crucial drivers of productivity growth.