• Membrane Journal
• /
• v.18 no.3
• /
• pp.198-205
• /
• 2008

A novel technology for homogeneous deposition of zeolite particles on a porous support was developed so that those particles played a seeding role for the growth of zeolite crystals. After the particles were dispersed in water, the aqueous solution was 134 through the bore of a porous tubular support. By keeping the other side of the support in a vacuum, the aqueous solution passed through the pores of the support, leading the particles to be homogeneously deposited on the support. The amount of the deposited particles was investigated by changing the following operating parameters: a particle concentration in the solution, a time for deposition, and the feeding rate of the solution. The amount of the deposited particles increased from 0.0019 g to 0.0208 g as the concentration of the particles was changed from 0.01 wt% to 0.3 wt%, while the feeding rate and the deposition time were kept to 100 mL/min and 4 min, respectively. As the deposition time was varied from 1 min to 4 min, the deposition amount increased from 0.0004g to 0.0019g at the typical condition of the rest parameters. Also, it was observed that the deposited weight increased from 0.0029 g to 0.01 g as the feeding rate increased from 100 mL/min to 300 mL/min. However, the total permeance of water and ethanol decreased through the zeolite membrane as the deposited weight increased.

• Applied Chemistry for Engineering
• /
• v.7 no.4
• /
• pp.743-749
• /
• 1996

A new static contractor using capillary phenomena induced by a highly packed fiber bundle was developed for the solvent extraction. When two immiscible phases being cocurrently and forcedly fed into the packed fiber bundle, the contactor brings about a very large liquid-liquid contact area for mass transfer within a small definite space without any turbulence and drop phenomena. In order to test the characteristics and stability of the static contractor system, continuous extraction experiments of TBP-uranyl ion-nitric acid system were done and compared with the batch extraction experiment of the same chemical system. The performance of the static contractor were the same as that of the ideal batch extractor with the same extraction condition. For the increase of the extraction yield by the contactor, the increase of organic flow rate was required at a fixed aqueous flow rate, and a certain residence time of the aqueous phase flow within the contactor system had to be maintained to meet the performance of the batch system of the same phase ratio. The residence time in the case of TBP-uranyl ion-nitric acid system was about 1.9 minutes. This system was confirmed to be effective and stable enough for purposes of the kinetic study of solvent extraction as well as the mutual separation and purification of ordinary materials because of good reproducibility and the stable and large static liquid-liquid contact area.

• Applied Chemistry for Engineering
• /
• v.7 no.3
• /
• pp.588-596
• /
• 1996

The optimum conditions of the 1st and 2nd distillation had been investigated to obtaine a high quality monomeric MDI and fire reactive polymeric MDI by purification of crude MDI. Effect of additives on the monomeric MDI's color change, dimerization and the reactivity of polymeric MDI with standard polyol system has been tested. When the monomeric MDI yield is approximately 32%, 4,4'-MDI content is above 98% in the monomeric MDI at the 1st distillation. When the separation ratio of initial portion and residue percentage, reflux ratio are set at respectively, approximately 20wt%, 9wt%, above 2 in order to minimize the content of 2,4'-MDI in monomeric MDI, the freezing point of final distilled monomeric MDI is above $38.4^{\circ}C$. Since the monomeric MDI is inherently unstable in the room condition, monomeric MDI easily changes it's color and conducts self-polymerization reaction. To increase the stability of monomeric MDI, the composition of antioxidant, which is composed of phenolic 1st antioxidant, phosphorus 2nd antioxidant, UV absorbent and Hindered amine light stabilizer are used, and benzoyl chloride as antipolymerization agent test are that APHA color is less than 20, dimer content is remained less than 0.36wt% after 45 days storage of monomeric MDI.

• Journal of Radiation Protection and Research
• /
• v.20 no.2
• /
• pp.103-115
• /
• 1995

For the determination of $^{222}Rn$ in water by a very simple and time saving liquid scintillation counting method that does not require any chemical separation, an optimum analytical condition has been investigated. The optimum pulse shape analysis(PSA) level for the measurement of $^{222}Rn$ using LKB 1220 Quantulus liquid scintillation counter was 110 for Optiphase HiSafe3 cocktail and 90 for toluene-based cocktail. The counting efficiencies of $^{222}Rn$ in the window covering u spectra using Optiphase HiSafe3 cocktail were 282.2% for glass vial and 271.6% for Teflon vial, whereas the counting efficiencies in toluene-based cocktail were 262.3% and 247.5% for glass and Teflon vials, respectively. The minimum detectable activity(MDA) in the u window for a 60-min measurement with a Teflon vial using Optiphase HiSafe3 cocktail was $0.30Bq/{\iota}$. The analytical method studied from this work was also applied to the determination of $^{222}Rn$ in some groundwater and hot spring water samples.

• Clean Technology
• /
• v.18 no.3
• /
• pp.229-249
• /
• 2012

At present, global warming and depletion of fossil fuels have been one of the big issues which should be solved for sustainable development in the future. CCS (carbon capture and sequestration) technology as the post $CO_2$ reduction technology has been considered as a promising solution for global warming due to increased carbon emission. However, the environmental and ecological effects of CCS have drawn concerns. There are needs for noble post reduction technology. More recently, CCU (carbon capture and utilization) Technology, which emphasizes transforming carbon dioxide into value-added chemicals rather than storing it, has been attracted attentions in terms of preventing global warming and recycling the renewable carbon source. In this paper, various technologies developed for carbon dioxide conversion both in gas and liquid phase have been reviewed. For the thermochemical catalysis in gas phase, the development of the catalytic system which can be performed at mild condition and the separation and purification technology with low energy supply is required. For the photochemical conversion in liquid phase, efficient photosensitizers and photocatalysts should be developed, and the photoelectrochemical systems which can utilize solar and electric energy simultaneously are also in development for more efficient carbon dioxide conversion. The energy needed in CCU must be renewable or unutilized one. CCU will be a key connection technology between renewable energy and bio industry development.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.29 no.1
• /
• pp.19-28
• /
• 2016

In the case of structural analysis for building structures, the super-structure and the sub-structure are analyzed by using separate structural models in the field because of time saving, facile result interpretation and easy analysis of dynamic behavior. However this separate structural model violated the compatibility condition of structural analysis and it can not consider the interaction of superand sub- structures. In the present study, the analysis results of this separate model were compared to those of the unified model of super- and sub- structures which can consider the interaction of super- and sub- structures and reflect the realistic boundary conditions. According to the comparison results, the the analysis model using separate models can underestimate the member force and deflection of structural members in the super-structures and overestimate the deflection and member force of sub-structures. Therefore, in the case of high-rise buildings, irregular shaped buildings, buildings which are expected to be affected by large differential settlement and remodeling buildings, the unified structural model for super- and sub- structures was recommended for structural analysis instead of the separate structural model.

• Management & Information Systems Review
• /
• v.32 no.4
• /
• pp.127-153
• /
• 2013

The trend of China's industry has been changed from manufacturing industry based on cheap labor market to service industries gradually as a whole. The investment of Korean corporations toward Chines service industry is gradually being increased. The importance of Chinese service industry related taxations such as business tax and value-added tax are growing. This study, therefore, examines the changes of investment environment and does the business tax and VAT of growing importance in China. From the point of view that the taxation on services is mainly related to the business tax or VAT, this study, also, examines the changes of present condition of investment and corresponding trends of the Korean corporations, in accordance with the domestic investment environment changes tied to the business tax and the VAT in China. With regard to the business tax and the VAT, this study looks into their features and tax requisition and also makes comparison between them and VAT of Korea. This study examines the problems and situations from the cases of separation, integration and trial integration of the business tax and VAT, and also does the development direction of the above two taxation and the corresponding strategy of Korea and her companies The purpose of this study is to provide information about the changing trends of investment environment and the business tax and VAT and to present corresponding plan for the corporations advancing into China.

• Proceedings of the Korea Crystallographic Association Conference
• /
• 2002.11a
• /
• pp.5-6
• /
• 2002

The new spectrometer for X-ray Induced Electron Emission Spectroscopy (XIEES) .has been recently developed in KRISS in collaboration with PTI (Russia). The spectrometer allows to perform research using the XAFS, SXAFS, XANES techniques (D.C.Koningsberger and R.Prins, 1988) as well as the number of techniques from XIEES field(L.A.Bakaleinikov et all, 1992). The experiments may be carried out with registration of transmitted through the sample x-rays (to investigate bulk samples) or/and total electron yield (TEY) from the sample surface that gives the high (down to several atomic mono-layers in soft x-ray region) near surface sensitivity. The combination of these methods together give the possibility to obtain a quantitative information on elemental composition, chemical state, atomic structure for powder samples and solids, including non-crystalline materials (the long range order is not required). The optical design of spectrometer is made according to Johannesson true focusing schematics and presented on the Fig.1. Five stepping motors are used to maintain the focusing condition during the photon energy scan (crystal angle, crystal position along rail, sample goniometer rail angle, sample goniometer position along rail and sample goniometer angle relatively of rail). All movements can be done independently and simultaneously that speeds up the setting of photon energy and allows the using of crystals with different Rowland radil. At present six curved crystals with different d-values and one flat synthetic multilayer are installed on revolver-type monochromator. This arrangement allows the wide range of x-rays from 100 eV up to 25 keV to be obtained. Another 4 stepping motors set exit slit width, sample angle, channeltron position and x-ray detector position. The differential pumping allows to unite vacuum chambers of spectrometer and x-ray generator avoiding the absorption of soft x-rays on Be foil of a window and in atmosphere. Another feature of vacuum system is separation of walls of vacuum chamber (which are deformed by the atmospheric pressure) from optical elements of spectrometer. This warrantees that the optical elements are precisely positioned. The detecting system of the spectrometer consists of two proportional counters, one scintillating detector and one channeltron detector. First proportional counter can be used as I/sub 0/-detector in transmission mode or by measuring the fluorescence from exit slit edge. The last installation can be used to measure the reference data (that is necessary in XANES measurements), in this case the reference sample is installed on slit knife edge. The second proportional counter measures the intensity of x-rays transmitted through the sample. The scintillating detector is used in the same way but on the air for the hard x-rays and for alignment purposes. Total electron yield from the sample is measured by channeltron. The spectrometer is fully controlled by special software that gives the high flexibility and reliability in carrying out of the experiments. Fig.2 and fig.3 present the typical XAFS spectra measured with spectrometer.

• Journal of the Korean association of regional geographers
• /
• v.7 no.1
• /
• pp.21-34
• /
• 2001

Summarized results of this study that examined the characteristics of farm household in suburban areas classified by the fanning types are as follows. When it was looked into with the side of farm household and his family, the type of the farm household in suburban areas are related to the quality of fanning labor rather than the quantity of it. Regardless of the type of the farm household, it depends upon the family labor (usually men and wives). And the age of farm manager is an important part in the quality of fanning labor. The size of the farm household is related to the individual fanning labor. The size of self-sufficient crops(mainly rice) farm household will be small as the farmer gets to be old. But the size of commercial crops farm household has less tendency to change in terms with the age of farm manager. The fanning commercialism takes an important part in the maintenance and development of suburban agricultural areas. But, in fact, there is a shortage of farming labor. So the physical condition of farmland is the most important part in agricultural durability. After this study, we can conclude that we won't have enough chance to solve the problem of family member separation and shortage of fanning labor even though it is in the suburban area or in the profitable farm until we give them more enough chance to get a job(except fanning) and the better education infrastructure. To make matters worse, the aggravation of farm house-hold's economy due to unstable price of farming products' threatens the agricultural durability. Consequently, in order to get a development of agriculture and rural community, a qualitative change with improvement of agricultural conditions and of products distribution system is needed.

• Journal of Conservation Science
• /
• v.26 no.4
• /
• pp.445-458
• /
• 2010

The deterioration and structural damage such as exfoliation, cracks, and separation of painted layer on the wall paintings of Maitreya Hall in Geumsan-sa temple have been accelerated since it was re-positioned to the original place after the dismantling from the building in 1993. The examination of which result and analysis described in this study, is a preliminary survey for establishing conservation plan of the wall paintings. It aimed at the understanding of the physical and chemical characteristics of the materials applied in the 1993 conservation. The research focused on the south walls which displayed the worst condition compared to other walls. Samples for the examination for the understanding of micro-structure, chemical composition, cristalisation, and particle distribution, were collected for finishing, middle, and consolidated layers of the walls between pillars and the ones between brackets. Those samples were collected from separated fragments of the walls. The sample analysis displayed that: 1. the 1993 conservation used the similar type of weathered soil as the original for the finishing layer, and such soil and sand for the middle layer; 2. those walls are composed of a group of mineral particles which are relatively equal in size and shape and in their distribution; 3. the mineral particles were cohered forming solid aggregate due to the application of acrylic resin for the reinforcement on the wall. The main composition of crystalisation on the first and the second reinforcement layers of the back walls were lime plaster ($CaSO_4{\cdot}2H_2O$). The overall examination confirmed that the priority of the future conservation treatment should be given to the removal of the first and the second layers of reinforcement and the treatment on the back walls which were partially consolidated.