• Korean Chemical Engineering Research
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• v.45 no.1
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• pp.81-86
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• 2007

Hollow fiber membrane G-L contactors are widely used to remove $SO_2$ emitted from industrial facilities. In this work, the mathematical modeling and computer simulation for hollow membrane G-L contactors is carried out to analyze $SO_2$ absorption behavior in hollow fiber membranes. The model is solved with the finite element method using a commercial software. Investigated is the dependency of $SO_2$ removal efficiency and mass transfer characteristics on gas velocities, membrane mass transfer coefficients and physical properties of contactors. The membrane mass transfer coefficients are estimated by fitting the experimental data with the simulated $SO_2$ removal efficiencies. In addition, a design methodology of membrane contactors is suggested.

• Journal of Korean Society of Forest Science
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• v.90 no.1
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• pp.90-104
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• 2001

This study is aimed to analyze and to evaluate the revegetation and soil conservation technology in desertification-affected sandy land, resulting from the project of "Studies on the desertification combating and sand industry development". Main native plants for combating desertification : The general characteristics of vegetation distribution in desertified regions are partially concentrated vegetation distribution types including the a) desert plants in low zone of desert or sanddune of depressed basin, b) salt-resistant plants around saline lakes, c) grouped vegetation with Poplar and Chinese Tamarix of freshwater-lakes, saline-lakes and river-banks, d) gobi vegetation of gravel desert and e) grassland and oasis-woods around the alluvial fan of rivers, etc. Generally, Tamarix ehinensis Lour., Haloxylon ammodendron Bunge., Calligonum spp., Populus euphratica Oliver., Elaeagnus angustifolia L., Ulmus pumila L., Salix spp., Hedysarum spp., Caragana spp., Xanthoceras sorbifolia Bunge., Nitraria tangutorum Bobr., Lespedeza bicolor, Alhagi sparsifolia Shap., Capparis spinosa L., Artemisia arenaria DC., etc. are widely distributed in desertified regions. It is necessary for conducting research in the native plants in desertified regions. Analysis of intensive revegetation technology system for combating desertification : In the wind erosion region, the experimental research projects of rational farming systems (regional planning, shelterbelts system, protection system of oasis, establishment of irrigation-channel networks and management technology of enormous farmlands, etc.), rational utilization technology of plant resources (fuelwood, medicinal plants, grazing and grassland management, etc.), utilization technology of water resources (management and planning of watershed, construction of channel and technology of water saving and irrigation, etc.), establishment of sheltetbelts, control of population increase and increased production technology of agricultural forest, fuelwood and feed, etc. are preponderantly being promoted. And in water erosion region, the experimental research projects of development of rational utilization technology of land and vegetation, engineering technology and protection technology of crops, etc. are being promoted in priority. And also, the experimental researches on the methods of utilization of water (irrigation, drainage, washing and rice cultivation, etc.), agricultural methods (reclamation of land, agronomy, fertilization, seeding, crop rotation, mixed-cultivation and soil dressing works, etc.) and biological methods (cultivation of salt-resistant crops and green manure and tree plantation, etc.) for improvement of saline soil and alkaline soil in desertified-lands are actively being promoted. And the international cooperations on the revegetation technology development projects of desertified-lands are sincerely being required.

• Proceedings of the Membrane Society of Korea Conference
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• 1994.10a
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• pp.77-79
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• 1994

폐수와 하수처리에서 양질의 재생수를 얻기위하여 고분자막을 이용한 폐수재활용에서 나타나는 공정상 문제점을 고찰하였다. 본 연구에서 사용한 폐수는 처탑공장의 폐수로서 RO막을 이용한 폐수의 재이용공정개발을 목표로하고 있으며, pilot실험을 토대로 폐수의 적용성 검토가 행하여졌다. 사용된 막의 종류는 중공사막형의 막으로서 막내의 층류 흐름의 응용은 투석막, 기체분리, 중금속의 추출등 상당한 관심속에 있다. 여기서 중공사막과 같은 관(Cynlindrical)형의 막 구조에서 물질과 에너지 이동현상은 막분리공정을 이해하는 중요한 물리적고찰로서 막투과도를 높힐수 있을 뿐만 아니라 운전온도에 의해 중공사막 RO막내의 유량변화에 주요한 변수가 될 수 있다.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.10a
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• pp.79-81
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• 1998

1. 서론 : 장 흐름 분획법(Field-Flow Fractionation, FFF)의 개발은 고분자 및 미세한 콜로이드 입자의 분리, 분석, 분취를 위한 빠르고 선택적인 분리방법의 필요성과 액체 크로마토그래피 의 경우 고정상에서 유발되는 시료흡착에 의한 칼럼 효율저하의 문제를 극소화하기 위한 필요에 의해서 출발하였다. 본 연구의 목적은 중공사막 흐름장 흐름 분획법에 사용되는 중공사막 칼럼을 개잘하여 칼럼내의 시료의 거동을 이론적으로 해석하여 분리능과 분리효율을 기존의 방식보다 향상시켜 여러 용도로 응용이 가능한 저렴한 칼럼의 개발의 가능성을 제시하는데 있다.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.10a
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• pp.50-52
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• 1998

1. 서론 : 오래전부터 기체를 액상에 분산시킴으로써 물질 전달 속도를 증가시킴과 동시에 기-액간의 접촉면적을 넓히려는 연구 즉, 기-액간의 접촉 경계면을 통하여 이루어지는 기체흡수에 관한 연구가 다각적으로 이루어져 왔다. 그러나, 기존의 흡수장치에서는 기-액간의 접촉면적을 정확히 계산할 수 없고, 기체에 의한 액체의 범람이나 편류현상등이 발생하여 액체나 기체의 유속에 제한을 주는 등 기술적인 문제점을 가지고 있다. 따라서 이러한 기존 흡수공정들의 문제점을 극복하기 위하여 최근에 제안된 것이 막을 이용하여 기체와 흡수제인 액체의 접촉을 인위적으로 제어할 수 있는 중공사막 접촉기이다. 본 연구에서는 수용성 흡수제가 흡수모듈과 탈착모듈을 순환하는 순환식 중공사막 접촉기를 이용하여 혼합기체(N$_2$/CO$_2$ = 80/20)로부터 이산화탄소를 선택적으로 분리.회수하고자 하였으며, 또한 흡수제의 농도, 유속변화, 그리고 진공식 탈착모듈에서 압력변화에 따른 기체투과 특성을 고찰함으로써 운전조건의 최적화와 그 응용 가능성을 제시하고자 하였다.

• Analytical Science and Technology
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• v.21 no.6
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• pp.474-479
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• 2008

Radioactivity of naturally occurring radioactive nuclides (NORN) such as $^{226}Ra$, $^{228}Ac$ and $^{40}K$ were investigated for surface sediments collected from Ordos, Alashan, Taklimakan deserts and Loess plateau regions in China. By a Gamma-ray spectrometry, specific activity (SA) and SA ratio (SAR) of the NORN were determined for each source region of Asian dust. Characterization of the source regions of Asian dust was performed with the SA and SAR values. SA of $^{226}Ra$ in the three desert regions have almost same values in the range of mean value 17.9~21.9 Bq/kg, however, the SA in Loess Plateau has much higher values in the mean value of 35 Bq/Kg. SA of $^{228}Ac$ in the Ordos and Alashan desert regions have almost same values in the range of mean value 27.1~27.2 Bq/kg, and those in Taklimakan desert and Loess Plateau were 31.7 and 49.0 Bq/kg, respectively. In case of 40K, the SA in all regions have similar values in the range of 636~943 Bq/kg. The mean SAR value of $^{226}Ra/^{228}Ac$ in four source regions was almost same in the range of 0.708-0.721. It is shown that relationship between $^{226}Ra$ and $^{228}Ac$ is clearly presented in the source regions. The mean SAR values of $^{226}Ra/^{40}K$, $^{228}Ac/^{40}K$ are 0.0209-0.056, 0.0287-0.0773, respectively.

• 산림경영
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• s.145
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• pp.25-33
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• 2000

• 산림경영
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• s.187
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• pp.6-7
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• 2008

• Membrane Journal
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• v.23 no.4
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• pp.257-266
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• 2013

The main purpose of this study is to develop a commercial scale of pervaporative process equipped with hollow fiber membrane modules, being able to effectually purify organic solvent at high temperature well over its boiling point under high vapor pressure. Three constituent technologies have been developed; 1) to fabricate braid-reinforced hollow fiber membrane stable in high pressure and high temperature application, 2) to design and fabricate a commercial scale of hollow fiber membrane module, and 3) to design and fabricate a pilot scale of pervaporation equipment system. The developed hollow fiber membrane possesses a membrane performance superior to the membrane of Sulzer (Germany) which is the most-well known for pervaporation process, and the membrane module equips hollow fiber membranes of $4.6m^2$ and the pervaporation system can treat organic liquid at 200 L/h, which is based on the dehydration of 95 wt% isopropyl alcohol (IPA). Since the membrane module is designed to flow in and pass through the inside of individual hollow fiber membrane, not to involve both the formation of feed's dead volume observed in flat-sheet membrane module and the channeling of feed occurring inside hollow fiber bundle which lower membrane performance seriously, it showed excellent separation efficiency. In particular, the module is inexpensive and has less heat loss into its surrounding, in compared with flat-sheet membrane module. In addition, permeant can be removed effectively from the outer surface of hollow fiber membrane because the applied vacuum is conveyed uniformly through space between fibers into respective fiber, even into one in the middle of the hollow fiber bundle in which the space between fibers is uniform in distance. Since the hollow fiber membrane pervaporation system is the first one ever developed in the world, our own unique proprietary technology can be secured, preoccupying technical superiority in export competitive challenges.

• Sijohaknonchong
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• v.30
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• pp.53-90
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• 2009

This study discusses the aspects of Korean-American Sjjo writers' consciousness of sijo and its significance, focusing primarily on the Sijo-Anthologies of Korean-American authors, "The Moon of the Desert" (1989), "The Dandelion of the Desert" (1994), and The Stars of the Desert" (1996) published by the Sijo Society of America. For this purpose, I thoroughly examined "Notes of Writing Sijo' attached to the authors' works and some other sijos added at the end of the paper. They started writing sijos quite early. Sijo has been recognized as a typical traditional genre of literature, and even foreigners came to write them in English. The following is the summary of the view on sijo propounded by Korean-American authors. Firstly, they follow traditional view on the theory of sijo in terms of its nature and utility, and at the same time they emphasize the utility of katharsis through self expressions. Secondly, their recognition of the value of sijo boils down to its formal patterns. Lastly, they develop the idea of national literature through their significance of writing sijos. They think that they can contribute to the development of national literature as well as the expression of patriotism through writing sijos. Therefore, they recognize themselves as spreaders of Korean culture to the local residents, and as the main stream enhancing the status of Korean culture through the competition with other nations.