• Transactions of the Korean hydrogen and new energy society
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• v.33 no.5
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• pp.598-606
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• 2022

With the advancement of industry, the use of various sustainable energy sources and solutions to problems affecting the environment are being actively requested. From this point of view, it is intended to directly burn unused biogas to use it as energy and to solve environmental problems such as greenhouse gases. In this study, a new type of cavity matrix combustor capable of low-emission complete combustion without complex facilities such as separation or purification of biogas produced in small and medium-sized facilities was proposed, and CFD numerical calculation was performed to understand the performance characteristics of this combustor. The cavity matrix combustor consists of a burner with a rectangular porous microwave receptor at the center inside a 3D cavity that maintains a rectangular parallelepiped shape composed of a porous plate that can store heat in the combustor chamber. As a result of numerical calculation, the biogas supplied to the inlet of the combustor is converted to CO and H₂, which are intermediate products, on the surface of the 3D matrix porous burner. And then the optimal combustion process was achieved through complete combustion into CO₂ and H₂O due to increased combustibility by receiving heat energy from the microwave heating receptor.

• YAKHAK HOEJI
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• v.50 no.1
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• pp.21-25
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• 2006

Reiterated normal-phase column chromatography lead to the isolation and purification of six known compounds but for the first time from the whole plant of Sasa borealis (Hack.) Makino (Gramineae): tricin 4'-O-(erythro-${\beta}$-guaia-cylglyceryl) ether (1), tricin 4'-O-(threo-${\beta}$-guaiacylglyceryl) ether (2), tricin 4'-O-[erythro-${\beta}$-guaiacyl-(9'-O-acetyl)-glyceryl] ether (3), tricin 4'-O-[threo-${\beta}$-guaiacyl-(9'-O-acetyl)-glyceryl] ether (4), (-)-pinoresinol (5), and vanillin (6). The structures of the compounds (1-6) were established based on interpretation of high resolution NMR (COSY, HSQC, HMBC, and NOESY) spectral data. In particular, compounds 1 and 3 were diastereomers of compounds 2 and 4, respectively. These two sets of diastereomers were able to be simultaneously identified and quantified by a gradient reversed-phase HPLC method with UV photodiode array, This sensitive HPLC method is noteworthy as a simultaneous separation and identification method to test the extract of the family Gramineae which contains these compounds.

• KSBB Journal
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• v.8 no.2
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• pp.143-149
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• 1993

Activated carbons were used to examine their performance for the separation of undesirable colored materials from culture broth containing hyaluronic acid. Six local samples and a NORIT ROX 08 were tested, whereas the latter was mainly studied under batch and continuous modes. The optimal wavelength for the detection of colored materials was 330nm. The optimal choice of NORIT ROX 08 provided 30% colored residuals with 96% hyaluronic acid recovery of original broth in batch experiments. The nonlinear adsorption behavior of protein and colored materials with activated carbon (C) was correlated by a Langmuir equation to give 18C/24+C and 500C/892+C for protein and colored materials, respectively. It appears that colored materials were composed of 78% protein and 22% glucose residuals on the basis of clearance results. A microscopic study using a scanning electron microscope suggests that regeneration of used activated carbon with 0.1N NaOH and hot water was not satisfactory. The present study proposes that the continuous monitoring of colored materials during purification can be accomplished by Installation of a UV monitor commonly used for continuous detection of protein during the process, as resulted from the significant correlation of color (A330)=0.353protein(mg/ml)+0.1(R=99.7%).

• Journal of Powder Materials
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• v.16 no.5
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• pp.351-357
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• 2009

A two-step recovery method was developed to produce copper powders from copper chloride waste solution as byproducts of MoO$_3$ leaching process. The first step consisted of replacing noble copper ions with external Fe$^{3+}$ ions which were formed by dissolving iron scraps in the copper chloride waste solution. The replaced copper ions were subsequently precipitated as copper powders. The second step was cementation of entire solution mixture to separate (pure) copper powders from aqueous solution of iron chloride. Cementation process variables of temperature, time, and added amount of iron scraps were optimized by using design of experiment method and individual effects on yield and efficiency of copper powder recovery were investigated. Copper powders thus obtained from cementation process were further characterized using various analytical tools such as XRD, SEM-EDS and laser diffraction and scattering methods.Cementation process necessitated further purification of recovered copper powders and centrifugal separation method was employed, which successfully yielded copper powders of more than 99% purity and average 1$\sim$2$\mu$m in size.

• Journal of the Korean housing association
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• v.26 no.6
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• pp.127-137
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• 2015

This investigation is to question as to whether and how much urban residential superblocks have changed the uses of facilities, as compared with original zoning plan. The difference between the original plan for 'land use' in 1960's and current 'building uses' has been examined on six superblocks in Seoul, and the reasons for change were analyzed. Investigation results are as follows: As the original urban planning was intended for use-purification by the subdivision of zones in a superblock through zoning, current buildings uses are different from the land-use. Commercial facilities are located in residential zone along community paths because of the necessity, and business buildings are placed on the appropriate-sized lots in the middle of residential blocks, due to the need of small and low-rent offices. Also, different types of residence have been built on convenient locations in commercial zone to meet various housing needs. In conclusion, the current zoning system plays a role of controling the volume of buildings rather than the use of land. Therefore, mixed use of land, not functional separation, becomes a natural phenomenon taken place in the contemporary cities, and it is high time to adopt a mixed-use zoning system.

• Journal of the Korean Chemical Society
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• v.42 no.1
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• pp.51-56
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• 1998

It is very difficult to separate and purify the microcystins, cyanobacterial toxins since it exist in a trace level in natural lakes. In this paper, we developed a new analytical method to separate and purify the microcystin RR and LR from the freeze-dried cyanobacterial cells in natural lakes. We used 7.5 g silica gel as a stationary phase and ethyl acetate: isopropanol: water (30: 45: 25) as a mobile phase and microcystins were eluted using an open column. The eluting solvent was collected in a small bottle at the intervals of 3 mL and the fractions were chromatographed with HPLC to confirm the microcystin RR and LR.

• The Journal of Korean Medicine
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• v.32 no.4
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• pp.68-74
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• 2011

Objective: The purpose of this study is to expatiate on high performance thin layer chromatography (HPTLC) as a simple, easy and scientific method for evaluation and standardization of herbal formulae. Methods: Through retrieving HPTLC application for herbal formulae in the literatures, the current situation of HPTLC application, and potential as well as limitation of HPTLC as a standardization method for multi-herbal drug was studied. Results: HPTLC is a speedy, inexpensive and well-operable tool for possessing multi-capability on component identification, separation, quantification and purification compared to other methods, such as high performance liquid chromatography (HPLC), gas chromatography (GC). Conclusions: HPTLC is considered as an available and convenient method for quality control and standardization of multi-herbal drugs. Thereby, this method could be recommended to widely applicate in the traditional Korean medicine.

• Proceedings of the Membrane Society of Korea Conference
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• 1999.07a
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• pp.43-47
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• 1999

Pd-ceramic composite membranes and catalytic membrane reactors(CMR) have been studied for hydrogen purification and recovery in th fusion reactor fuel cycle. The development of techniques for coating microporous ceramic tubes with Pd and Pd/Ag layers is described: composite membranes have been produced by electroless deposition (Pd/Ag film of 10-20${\mu}{\textrm}{m}$) and rolling of thin metal sheet (Pd and Pd/ Ag membranes of 50-70 ${\mu}{\textrm}{m}$). Experimental results on electroless membranes showed that the metallic film presented some defects and the membranes had not complete hydrogen selectivity . Then the catalytic membrane reactors with electroless membranes can be applied for some industrial processes that do not require a complete separation of the hydrogen (i.e. in the dehydrogenation of hydrocarbons). The rolled thin Pd/Ag membranes separated the hydrogen from the other gas with a complete selectivity and exhibited a slightly larger (about a factor 1.7) mass transfer resistance with respect to the electroless membranes. Experimental tests confirmed the good performances in terms of durability.

• The Korean Journal of Mycology
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• v.16 no.1
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• pp.9-15
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• 1988

Two kinds of toxins were demonstrated in the culture filtrate of H. sativum, and were called 'M' and 'D' toxins. The lettuce bioassay indicated that D-toxin caused less root growth inhibition than M-toxin. Chemical analysis indicated that M-toxin was a very unusual small peptide. D-toxin was shown to have chemical characteristics similar to helminthosporal based on ultraviolet, proton nuclear magnetic resonance and mass spectra. D-toxin was composed of at least two isomers.

• Clean Technology
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• v.16 no.1
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• pp.64-70
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• 2010

In this study, we suggest the application of the divided-wall column (DWC) to the existing trichlorosilane(TCS) purification process in the commercial polysilicon manufacturing process. Using Aspen HYSYS V7.1, an extensive simulation study was carried out for the analysis of the energy consumptions and capital cost for the conventional sequential distillation configuration and the DWC for producing a given purity and yield of trichlorosilane. As a result, it is shown that the DWC saves the separation energy by 61% and the equipment cost by 58% compared with the conventional distillation process.