• Journal of the Mineralogical Society of Korea
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• v.17 no.1
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• pp.23-35
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• 2004

The weathering characteristics of periodically submerged sedimentary rocks in the Sayeon dam, Ulsan was examined by field work, electron probe micro-analysis, X-ray diffraction, and X-ray fluorescence spectrometry. Analysis of fracture zone and exfoliation showed the submerged sedimentary rocks have undergone severe mechanical weathering. Mechanical weathering in the water-rock interface accelerated chemical weathering, such as dissolution and alteration of the most of minerals except for quartz in the weathering zone. The dissolution of carbonates specially calcite, is remarkable creating the cavities, whereas formation of minerals including clay minerals is not active. The sedimentary rocks have been periodically submerged for a certain period of time, and have repeated freezing and thawing. This mechanical weathering favored infiltration, which accelerated mineral dissolution. The high content of easily soluble carbonate of the sedimentary rocks is likely the major cause of intense chemical weathering. The dissolved elements within the infiltrated water interrupted the occurrence of clay and weathering minerals, and expend fractures by infiltrated water accelerated weathering process.

• Carbon letters
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• v.28
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• pp.116-120
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• 2018

Nitrogen-doped carbons have attracted much attention due to their novel application in relation to gas storage. In this study, nitrogen-doped porous carbons were synthesized using SBA-15 as a template, polypyrrole as the carbon and nitrogen precursor, and KOH as an activating agent. The effect of the activation temperature ($600-850^{\circ}C$) on the $CO_2$ adsorption capacity of the obtained porous carbons was studied. Characterization of the resulting carbons showed that they were micro-/meso-porous carbon materials with a well-developed pore structure that varied with the activation temperature. The highest surface area of $1488m^2g^{-1}$ was achieved at an activation temperature of $800^{\circ}C$ (AC-800). The nitrogen content of the activated carbon decreased from 4.74 to 1.39 wt% with an increase in the activation temperature from 600 to $850^{\circ}C$. This shows that nitrogen is oxidized and more easily removed than carbon during the activation process, which indicates that C-N bonds are more easily ruptured at higher temperatures. Furthermore, $CO_2$ adsorption isotherms showed that AC-800 exhibited the best $CO_2$ adsorption capacity of $110mg\;g^{-1}$ at 298 K and 1 bar.

• Journal of the Korean Ceramic Society
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• v.47 no.6
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• pp.560-565
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• 2010

Nano laminated bulk $Ti_3SiC_2$ was synthesized by hot press process using TiCx/Si powder mixture at the temperature range of $1300^{\circ}C\sim1500^{\circ}C$. pure $Ti_3SiC_2$ was synthesized by a hot pressing above $1400^{\circ}C$, while unreacted TiCx were remained in bulk $Ti_3SiC_2$ which synthesized below $1400^{\circ}C$. The sintering density of bulk $Ti_3SiC_2$ were varied with the amount of TiCx. It was found that the mechanical properties and micro structures of bulk $Ti_3SiC_2$ were closely related to the amounts of TiCx which was controlled by the hot pressing temperature. The TiCx increase the flexural strength of bulk $Ti_3SiC_2$, while the fracture toughness and thermal shock resistance of bulk $Ti_3SiC_2$ were decreased with the content of TiCx. The plastic deformations of bulk $Ti_3SiC_2$ were appeared above $1000^{\circ}C$.

• Journal of The Korean Association For Science Education
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• v.13 no.3
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• pp.366-376
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• 1993

In this study, a part of high school science instructional materials is evaluated by Instructional Quality Profile(IQP) based on the Merrill's Component Display Theory(CDT). The CDT is based on the Gagne's assumption of different conditions of learning for different outcomes. The IQP enables the user to check both the consistency and adequacy of existing cognitive instruction. The IQP can be used to predict student performance, and also to design and develop new instructional materials. The instructional components are classified according to 5 task levels; An Use-Generalities on Newly Encountered Examples(UGeg), A Remember-Paraphrased-Generalities(RpG), A Remember-Verbatim-Generalities(RvG), A Remember-Paraphrased-Examples (Rpeg). A Remember-Verbatim-Examples (Rveg). The analyses are composed of 3 parts; Justifying the task level of objectives, Objective-test consistency, and Test-presentation consistency. The objectives, the presentations and the tests given in a teacher's guide and a textbook are analyzed. The results show that the task levels and the content levels of the objectives are not consistent with those of the tests. And the indices of the test-presentation consistency indicate the presentation problems of the instructional materials.

• Journal of the Korean Applied Science and Technology
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• v.30 no.1
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• pp.88-95
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• 2013

This study attempts to capture the low level carbon dioxide from indoor spaces using a granular activated carbon (WSC-470) which was modified with primary monoethanolamine. Adsorption capacity of the prepared adsorbents was evaluated for pure $CO_2$ flow and 3000 ppm as a function of MEA concentration and solvents such as distilled water, ethanol and methanol. The AC based adsorbents then were characterized in terms of pore structure by BET and chemical functionalities by XPS. While high concentration of MEA reduced specific surface area, porosity and micro pores, nitrogen content which can enhance the surface basicity was increased. The maximum adsorption capacity decreased comparing to the initial AC pellets, whilst the potential of selective adsorption amount at low level $CO_2$ was increased at 45% (0.73 mmol/g).

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.4
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• pp.485-493
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• 2015

This study evaluated the in situ ruminal degradability, and subsequent small intestinal digestibility (SID) of dry matter, crude protein (CP), and amino acids (AA) of cottonseed meal (CSM), sunflower seed meal (SFSM) and distillers dried grains with solubles (DDGS) by using the modified three-step in vitro procedure. The ruminal degradability and subsequent SID of AA in rumen-undegradable protein (RUP-AA) varied among three protein supplements. The result show that the effective degradability of DM for SFSM, CSM, and DDGS was 60.8%, 56.4%, and 41.0% and their ruminal fermentable organic matter was 60.0%, 55.9%, and 39.9%, respectively. The ruminal degradable protein (RDP) content in CP for SFSM, CSM, and DDGS was 68.3%, 39.0%, and 32.9%, respectively, at the ruminal solid passage rate of 1.84%/h. The SFSM is a good source of RDP for rumen micro-organisms; however, the SID of RUP of SFSM was lower. The DDGS and CSM are good sources of RUP for lambs to digest in the small intestine to complement ruminal microbial AA of growing lambs. Individual RUP-AA from each protein source was selectively removed by the rumen microorganisms, especially for Trp, Arg, His, and Lys (p<0.01). The SID of individual RUP-AA was different within specific RUP origin (p<0.01). Limiting amino acid was Leu for RUP of CSM and Lys for both RUP of SFSM and DDGS, respectively. Therefore, different protein supplements with specific limitations should be selected and combined carefully in growing lambs ration to optimize AA balance.

• Journal of the Korean Society of Costume
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• v.22
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• pp.23-44
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• 1994

The purpose of this study was to clarify the cultural characteristic of dress and adornments by examining articles on dress adornments and related items in Korean newspaper over periods historically and objectively by means of content analysis. This study attempted to at-tain a macro-cultural view by analysing to at-tain a macro-cultural view by analysing closely the cultural characteristics of dress and adornments as a micro-cultural system through culturally based model suggested by hamilton. The two-hundreds and eighty articles on dress and adornments were selected from newspapers(most by form Chosun Ilbo and partly from Maeil Shinbo) pulished between 1920 and 1990. The results were as follows: 1. The culture of dress and adornment received much attention during the 1930's and 1960's and little during 1950's. 2. Various cultural characteristics of dress and adornments appeared on and after 1960's: reporting more foreign news items showing foreign-oriented and future-oriented features showing cultural relativism. In the 1920's and 1970's the contents of news items on dress and adornments show the most common- mass- oriented character. Foreign-oriented cultural tendencies in cloth-ing were increasing during from 1960's to 1970's but the tendencies were turned to rather tradition-oriented features on and after 1980's compare with 1960's-1970's. Advisory critical articles on dress and adornments were small in number and insignificant but compare with other periods these received much atten-tion during the 1920's and 1980's. 3. Ideological components received much at-tention on and after 1920's to 1990. Techo-nological components received much attention during 1920's and little during 1960's. The social structural components received a little attention on and after 1920's-1940's and 1990. 4. News items on women's dress and adornments received much attention from the 1920's to 1960's and news items on both men's and women's dress and adorments were in-creasing and received much attention on and after the 1970's. 5. The pragmatic cultures were mostly re-lated to techonological components and evaluative-normative culture were mostly re-lated to ideological and social structural components. In the light of these results dress and adorments as a cultural sub-system comprise a dynamic inteacting system that articulated directly with the macro-cultural system.

• Environmental Analysis Health and Toxicology
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• v.5 no.3_4
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• pp.29-36
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• 1990

Aflatoxins, produced by strains of Aspergillus flavus and Aspergillus parasiticus, can be found worldwide in corn, barley, peanuts, and other commodities. Among this group of toxins, aflatoxin B$_1$was realized to be one of the most potent environmental carcinogens, mutagens and teratogens. It is routinely monitored by methods such as thin layer chromatography, liquid chromatography, fluorodensitometric technique and radioimmunoassay. However, these assays are expensive, necessitate radioactive reagents, and require overnight incubation. In this study, the determination of fungal flora in several sorts cereals has been carried out in order to obtain an appropriate information of the population of fungi. The quantitative analysis of aflatoxin B$_1$has been carried out by High Performance Liquid Chromatography (HPLC) method and Enzyme Linked Immunosorbent Assay (ELISA). The results were summarized as follow: 1) From the 100 samples,313 colonies of fungi were isolated. Among the 313 colonies, 274 were possible to identify into 11 genera. The identified genera were Aspergillus Penicillium, Mucor, Rhizopus, Alternaria, Cladosorium, Fusarium, Circinella, Chrysosporium, Paecilomyces and Phoma. 2) Six of Aspergillus flavus were aflatoxin-producing strains. Aspergillus flavus isolated from sample barleys was contained the highest content (21.8 $\mu\textrm{g}$/ml) of aflatoxin B$_1$. 3) The yield of aflatoxin B$_1$-oxime compound was appromately 75%. Aflatoxin B$_1$-oxime-Human serum albumin was approved by formal consent as complete antigen. 4) Direct competitive ELISA permitted detection of 0.15 ng levels. In the quantitative microanalysis, ELISA was superior to HPLC method.

• Transactions of Materials Processing
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• v.17 no.4
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• pp.240-248
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• 2008

The effect of alloying elements(Mn, S, Mo, B) on the high temperature deformation behavior of Fe-29%Ni-17%Co (Kovar) alloy were investigated. And the effect of high temperature oxidation on the hot ductility was also studied. The hot ductility of Kovar alloy was drastically increased with the addition of Mn and lowering of S content. It has been found that the brittle intergranular fracture at high temperature cracking is closely associated with the FeS sulfide along the grain boundary. When Mn was added, the type of sulfide was changed to MnS from FeS and ductile intergranular fracture and transgranular fracture were promoted. The formation of oxide layer was found to have minimized the hot ductility of the Kovar alloy significantly. Grain boundary micro-cracks in the internal oxide region were noted following deformation due to high temperature, one of which acting as a notch that caused the poor hot workability of the oxidized specimen. The addition of Mo to the Kovar alloy could also retard the decrease in the hot ductility of the oxidized specimen through the prevention of notching due to internal oxidation. Hot ductility was remarkably improved by the addition of Boron. The improvement of hot ductility results from the grain boundary migration mainly due to the dynamic recrystallization at lower temperature range ($900{\sim}1000^{\circ}C$).

• Journal of Plant Biotechnology
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• v.5 no.1
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• pp.1-6
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• 2003

The adventitious root of Panax ginseng C.A. Meyer is regarded as an efficient alternative to cell culture or hairy root culture for biomass production due to its fast growth and stable metabolite production. To determine optimal culture conditions for the bioreactor culture of ginseng roots, experiments have been conducted on physical and chemical factors such as bioreactor type, dissolved oxygen, gas supply, aeration, medium type, macro- and micro-elements, medium supplement during culture period, sucrose concentration, osmotic agents, medium pH and light. Elicitation is a key step to increase ginsenoside accumulation in the adventitious roots but biomass growth is severely inhibited by elicitor treatment. To obtain high ginsenoside content with avoiding biomass decrease, we applied two-stage bioreactor culture system. Ginseng adventitious roots were cultured for 40 days to maximize biomass increase followed by elicitation for 7 days to enhance ginsenoside accumulation. We also experimented on types and concentrations of jasmonate to determine optimal elicitation methods. In this paper, we discussed several factors affecting the root propagation and ginsenoside accumulation. Based on the results obtained from previous experiments we have established large-scale bioreactor system (1 ton-10 ton) for the efficient production of ginseng adventitious roots and bioactive compounds including ginsenoside. Still, experiments are on going in our laboratory to determine other bioactive compounds having effects on diet, high blood pressure, DPPH elimination and increasing memories.