• 환경위생공학
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• 제16권1호
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• pp.61-65
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• 2001

To review mass transfer trays from a process of view, the dependence of efficiency in loading ranges and maximum loadings with an acceptable efficiency of traditional tray have to be known. It is reported about the performance of the metallic Dualflex, relatively new high performance packing. Absorption, desorption and rectification tests as well as pressure drop and maximum capacity are concerned, indicate the superiority of the Dualflex over the general packing of comparable, main process. The process engineering characteristics show that Dualflex can be applied for all mass transfer precesses and it is to be recommended especially for those high capacity separations which requite allow low pressure drop because of the thermal sensibility of the product or because of the need of energy saving.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2005년도 총회 및 춘계학술발표회
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• pp.352-358
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• 2005

This study aims to separate hydrograph into baseflow and event water to calculate baseflow rate during a rainfall in small catchments, Yuseong, Daejeon, The hydrograph of stream during a period with no excess rainfall will decay. The discharge is composed entirely of groundwater contributions. During the period, the Cl concentration of the stream water can be regarded as being in equilibrium with that of the groundwater. Using Cl as a conservative tracer, two-component hydrograph separations were performed from end point of the period to next end point. The required data were obtained by monitoring of the surface water table, along with discharge rate of stream. Cl concentration of rainfall, surface water were measured and recorded. Hydrograph separation, a mixing model using chemical tracer is applied to chemical hydrograph separation technique. These results show that baseflow rates are 31.6% of rainfall in the catchments during study period.

• 대한지하수환경학회지
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• 제3권1호
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• pp.15-20
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• 1996

지하수법에 용어는 명시되어 있지만 정의되지 않은 지하수 부존량 및 개발가능량을 수문학적 기반에 의하여 실무적으로 쉽게 사용할 수 있도록 그 개념을 명확히 정의하였다. 또한 기존의 지하수 함양량 추정기법들의 비교 분석을 통하여 물리적 의미를 가진 단순한 방법으로 지하수 개발가능량을 산정하는 방법을 제시하였다. 그것은 갈수기간과 지하수 함양기간에서 수문곡선으로부터 지하수유출 곡선의 분리에 기초한 방법으로, 수문곡선 분석시 제시된 기법을 일관성 있게 적용할 수 있다.

• 대한교통학회:학술대회논문집
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• 대한교통학회 2003년도 제43회 학술발표회논문집
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• pp.21-71
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• 2003

Previous alignment optimization models have not adequately considered intersections and other structures such as bridges, tunnels, grade separations and interchanges which can very strongly affect alignment decisions. This paper develops comprehensive cost functions for intersections and other structures and incorporates them in recently developed highway alignment optimization models connected with genetic algorithms and geographical information systems. The result is a fast and computerized process for extracting, analyzing spatial data, evaluating candidate alignments and optimizing them. A method for locally optimizing intersections is also developed. It improves search flexibility by saving good alignments whose unacceptable crossing angles with existing roads can be fixed, Through case studies, the developed model is found to produce feasible and efficient solutions.

• KSBB Journal
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• 제20권3호
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• pp.133-141
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• 2005

This review presents the preparation, transport mechanism and application of molecularly imprinted membranes (MIM). Molecular imprinting has now been established as a technique which allows the creation of tailor-made binding sites for many classes of compounds. MIM have some advantages; a high capacity due to a large surface area, faster transport of substrate molecules and faster equilibrium of binding cavities compared to molecularly imprinted particles. MIM were prepared by covalent and non-covalent chemical bonding systems, by interactions between functional monomer and template. MIM can be prepared by in-situ polymerization, wet phase inversion, dry phase inversion, and surface imprinting method. MIM can continuously separate mixtures based on facilitated or retarded diffusion of the template. MIM can change their permeability in the presence of templates. MIM have a potential to be used to separate chiral compounds and materials with similar structures. However the application of MIM by the chemical industries is still in its infancy stages.

• 대한치과의사협회지
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• 제19권7호통권146호
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• pp.609-614
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• 1981

Effects of steroid hormones on the collagen biosynthesis in aorta and uterus were studied with ovariectomized Sprague-Dawley rats. Effects of administration of hormones, such as estrogen, testosterone and prednisolone, to the ovariectomized animals were studied, comparing with the control. Each group was injected with ³H-proline and sacrificed, followed by removals of aorta and uterus. Separations and quantitative analyses of proline and hydroxyproline were performed by means of thin layer chromatography; and radioactivities of the separated amino acids were assayed by liquid scintillation counter. Normally the incorporation of ³H-proline into hydroxyproline was greater in uterus than in aorta, and collagen turnover rate of uterus was observed rapid as well than that of aorta. In the two tissues from ovariectomized rats, the incorporation rate of ³H-proline into hydroxypoline was markedly decreased than that of the former. Changes in the turnover rate of collagen in these tissues were not observed. Decrease in ³H-proline incorporation into collagen in ovariectomized rats was markedly antagonized by estrogen, but not influenced by prednisolone in the tissues tested.

• Wind and Structures
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• 제7권2호
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• pp.71-88
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• 2004

In this paper the capacity of Covariance Proper Transformation (CPT) analyses to provide information about the wind loading mechanisms of bluff bodies is investigated through the application to square cylinders. CPT is applied to the fluctuating pressure distributions on a single cylinder, as well as on a pair of cylinders in the tandem and side by side arrangements, with different separations. Both smooth and turbulent flow conditions are considered. First, through the analysis of the contributions of each CPT mode to the total fluctuating aerodynamic forces, a correspondence between modes and aerodynamic components is sought, which is then verified through examination of the mode shapes. When a correspondence between modes and aerodynamic components is found, an attempt is made to separate the different frequency contributions to the aerodynamic forces, provided by each mode. From the analyses it emerges that (a) in most cases each mode is associated to one single force component, that (b) retaining a limited number of modes allows reproducing the aerodynamic forces with a rather good accuracy, and that (c) each mode is mainly associated with one frequency of excitation.

• Nuclear Engineering and Technology
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• 제43권4호
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• pp.335-342
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• 2011

As part of the Department of Energy's Fuel Cycle Research and Development Program an electrochemical technology employing molten salts is being developed for recycle of metallic fast reactor fuel and treatment of light water reactor oxide fuel to produce a feed for fast reactors. This technology has been deployed for treatment of used fuel from the Experimental Breeder Reactor II (EBR-II) in the Fuel Conditioning Facility, located at the Materials and Fuel Complex of Idaho National Laboratory. This process is based on dry (non-aqueous) technologies that have been developed and demonstrated since the 1960s. These technologies offer potential advantages compared to traditional aqueous separations including: compactness, resistance to radiation effects, criticality control benefits, compatibility with advanced fuel types, and ability to produce low purity products. This paper will summarize the status of electrochemical development and demonstration activities with used nuclear fuel, including preparation of associated high-level waste forms.

• Macromolecular Research
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• 제15권2호
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• pp.134-141
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• 2007

The direct chromatographic separation of enantiomers by chiral stationary phases (CSPs) has been extensively developed over the past two decades, and has now become the most popular method for the analytical and preparative separations of enantiomers. Polysaccharide derivatives coated onto silica gel, as CSPs, playa significantly important role in the enantioseparations of a wide range of chiral compounds using high-performance liquid chromatography (HPLC). Unfortunately, the strict solvent limitation of the mobile phases is the main defect in the method developments of these types of coated CSPs. Therefore, the immobilization of polysaccharide derivatives onto silica gel, via chemical bonding, to obtain a new generation of CSPs compatible with the universal solvents used in HPLC is increasingly important. In this article, our recent studies on the immobilization of polysaccharide derivatives onto the silica gel, as CSPs, through radical copolymerization with various vinyl monomers are reported. Polysaccharide derivatives, with low vinyl content, can be efficiently fixed onto silica gel with high chiral recognition.

• Journal of Mechanical Science and Technology
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• 제19권8호
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• pp.1682-1691
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• 2005

Direct numerical simulation database of an axial turbulent boundary layer is used to compute frequency and wave number spectra of the wall shear-stress fluctuations in a low-Reynolds number axial turbulent boundary layer. One-dimensional and two-dimensional power spectra of flow variables are calculated and compared. At low wave numbers and frequencies, the power of streamwise shear stress is larger than that of spanwise shear stress, while the powers of both stresses are almost the same at high wave numbers and frequencies. The frequency/streamwise wave number spectra of the wall flow variables show that large-scale fluctuations to the rms value is largest for the stream wise shear stress, while that of small-scale fluctuations to the rms value is largest for pressure. In the two-point auto-correlations, negative correlation occurs in streamwise separations for pressure, and in span wise correlation for both shear stresses.