• Journal of the Korea Concrete Institute
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• v.21 no.6
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• pp.713-718
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• 2009

Advanced industries-IT, BT, NT and ET are rapidly developing in 21 century. And the cement industry is becoming the principal factor in air pollution because of the creation of $CO_2$ during manufacturing. Also, the cement industry will be faced with a crisis due to the exhaustion of natural resources. In this study, nano cement by Bottom-up method of a chemical synthesis was developed. The generation of $CO_2$ during the plasticization process of cement manufacturing was avoided. The purpose was to produce building materials that have both high strength and durability as the high value-added growth engine industry of the 21 century. The nano cement was developed using hydrothermal synthesis. This is a method of mixing after ripening, by manufacturing the high density gel and low gel, which does not require special test equipment or pressure conditions to produce. Particle size, SEM, EDX, and porosity tests were conducted. This study investigated the compressive strength of concrete with various compositions. Specimens were tested for compressive strength at 3, 7, 14 and 28 days. The medium-sized (50% by weight) cement particles created by chemical synthesis were less than 168 nm. The compressive strength of the mortar prepared using this cement was 53.9 MPa. But it was judged that succeeding study will be necessary for development of nano building materials with high ability and economical analysis.

• KSBB Journal
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• v.16 no.6
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• pp.603-608
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• 2001

In this study, we studied on the remeval of toluene vapors in a lab-scale biofilter. Biofiltration was performed in a column fed downflow with contaminated air at ambient conditions. The column was packed with mixture of Peat and Calstene(5:3 vol. Ratio), Synthesized media, Bark and Wood chip, which were inoculated with microbial population of selected stains(Pseudomonas. putida, KCCM 11343, ATCC 12633). The microorganisms were immobilized on the bed medium and then biofilm were formed. The biofilter was operated under the conditions of various inlet toluene concentrations for 180 days and treated up to the elimination capacity of maximum 40 g/㎥hr at the inlet load of 30 g/㎥ hr with percentage removals of 20∼90% and gas retention times between 1 and 2 min. The pressure drop was very negligible through the biofilter columps because its value of 0.054 cmH$_2$O/m was much less than others. The effect of operating conditions such as flow rate, inlet toluene concentration and moisture contents on the performance of the biofilter was sequentially investigated in this study.

• The Journal of Internal Korean Medicine
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• v.25 no.3
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• pp.461-472
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• 2004

Objectives : For the screening of neuroprotective effects of medicinal herbs, the complex system of animal models suffer some disadvantages in controlling critical parameters such as blood pressure and body temperature. Additionally, application of drugs to the appropriate brain area sometimes is difficult, due to poor permeability though the blood brain barrier, and so potential protective effects might be masked. Methods : Organotypic hippocampal slice culture (OHSC) method has the advantages of being relatively easy to prepare and of maintaining the general structure, including tissue integrity and the connections between cells. Drugs can easily be applied and neuronal damage can easily be quantified by using tissues and culture media. This study demonstrates neuroprotective effects of Puerariae radix (葛根, PR), Salviae miltiorrhizae radix (丹蔘, SR), Rhei rhizoma (大黃, RR), and Bupleuri radix (柴胡, BR). These were screenedand compared to MK-801, antagonist of NMDA receptors, by using OHSC of 1 week-old Sprague-Dawley rats. Oxygen/glucose deprivation (OGD) were conducted in an anaerobic chamber $(85%\;N_2,\;10%\;CO_2\;and\;5%\;H_2)$ in a deoxygenated glucose-free medium for 60 minutes. Water extracts of each herbs were treated to culture media with $5\;{\mu}g/ml$ for 48 hours. Results : Neuronal cell death in the cultures was monitored by densitometric measurements of the cellular uptake of propidium iodide (PI). PI fluorescence images were obtained at 48 hours after the OGD and medicinal herb treatment. Also TUNEL-positive cells in the CAI and DG regions and LDH concentrations in culture media were measured at 48 hours after the OGD. According to measured data, MK-801, PR, SR and BR demonstrated significant neuroprotective effect against excessive neuronal cell death and apoptosis induced by the OGD insult. Especially, PR revealed similar neuroprotective effect to MK-801 and RR demonstrated weak neuroprotective effect. Conclusions : These results suggest that OHSC can be a suitable method for screening of neuroprotective effects of medicinal herbs. (This work was supported by the research program of Dongguk University and Grant 01-PJ9-PG1-01CO03-0003 from Ministry of Health & Welfare.)

• Applied Chemistry for Engineering
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• v.28 no.3
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• pp.332-338
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• 2017

The objective of this work was to study the low temperature vacuum adsorption technology applicable to small and medium scale painting plants, which is the main emission source of volatile organic compounds. The low-temperature vacuum swing adsorption (VSA) technology is the way that the adsorbates are removed by reducing pressure at low temperature ($60{\sim}90^{\circ}C$) to compensate disadvantages of the existing thermal swing adsorption (TSA) technology. Commercial activated carbon was used and the absorption and desorption characteristics of toluene, a representative VOCs, were tested on a lab scale. Also based on the lab scale experimental results, a $30m^3min^{-1}$ VSA system was designed and applied to the actual painting factory to assess the applicability of the VSA system in the field. As a result of lab scale experiments, a 2 mm pellet type activated carbon showed higher toluene adsorption capacity than that of using 4 mm pellet type, and was used in a practical scale VSA system. Optimum conditions for desorption experiments were $80{\sim}90^{\circ}C$ and 100 torr. In the practical scale system, the adsorption/desorption cycles were repeated 95 times. As a result, VOCs discharged from the painting factory can be effectively removed upto 98% or more even after repeated adsorption/desorption cycles when using VSA technology indicating potential field applicabilities.

• Korean Journal of Plant Resources
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• v.27 no.5
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• pp.401-414
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• 2014

In an attempt to evaluate licorice quality based on its biological activity, we grafted an on-line high-performance liquid chromatography (HPLC) bioassay method into the previously established HPLC analysis method. The common antioxidant peaks in licorices of various origin were observed through an on-line HPLC/DPPH system leading to a decrease in absorbance at 517 nm for 2,2-diphenyl-1-picrylhydrazyl (DPPH). Among them, the licorice from Youngju possessed the highest activity. Therefore, three active standard compounds from the dehydroglyasperin C, dehydroglyasperin D, and isoangustone A, were isolated and elucidated by medium pressure liquid chromatography (MPLC) and instrumental analysis such as nuclear magnetic resonance (NMR), respectively. On-line HPLC/ABTS analysis method with the simultaneous determination of three standard compounds and their radical scavenging activity was established for the quality evaluation of licorices. 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid radicals (ABTS) which is stable and effective was used in replace of DPPH. The radical scavenging activity of three standards is compared with that of Trolox, known as antioxidant, showing a negative peak with a decrease in absorbance at 734 nm for ABTS. This on-line HPLC/ABTS analysis method was validated for specificity, linearity, precision and accuracy in compliance with international conference on harmonization (ICH) guideline.

• 한국해양학회지
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• v.29 no.4
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• pp.325-337
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• 1994

The distributions of heat and momentum fluxes on the surface over the oceans around the Korean Peninsula are obtained based on the surface-layer flux model of Kim and Kang (1994), and their seasonal variations are examined in the present study. the input data of the model is the oceanatmosphere data with a grid interval of 2$^{\circ}$ in longitude and latitude. The atmosphere data, which are the pressure, temperature, and specific humidity on the 1000 mb level for 3 year period of 1985∼1987, are obtained from the European center for Medium Range Forecast. The sea surface temperature (SST) is obtained from National Meteorological Center (NMC). The solar insolation and longwave radiation on the ocean surface are obtained, respectively, from the NASA satellite data and based on an emprical formula. It is shown from the net heat flux that the oceans near Korea lose heat to the atmosphere in January and October with the rates of 200∼ 400 Wm/SUP -2/ and 100 Wm/SUP -2/, respectively. But the oceans are heated by the atmosphere in April and July with about the same rate of 100 Wm/SUP -2/. The annualmean net heat flux is negative over the entire domain except the northern part of the Yellow Sea. The largest annual-mean cooling rate of about 120 Wm/SUP -2/ is appeared off the southwest of Japan. In the East Sea, the annual-mean cooling rate is 60∼90 Wm/SUP -2/ in the southern and northern parts and about 30 Wm/SUP -2/ in the middle part. The magnitude of wind stress in january is 3∼ 5 times bigger than those of the other months. As a result, the spatial pattern of annual-mean wind stress is similar to that of January. It is also shown that the annual-mean wind stress curl is negative. in the East China Sea and the South Sea,but it is positive in the northern part of the Yellow Sea.In the East sea,the stress curl is positive in the southeast and northern parts and negative in the northwestern part.

• Journal of Applied Biological Chemistry
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• v.62 no.4
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• pp.399-406
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• 2019

The roots of Scrophularia buergeriana were extracted with 80% aqueous Methanol and the concentrates were partitioned into EtOAc, n-BuOH, and H₂O fractions. The repeated silica gel or octadecyl SiO₂column, and medium pressure liquid chromatographies for the n-BuOH fraction led to isolation of phenylethanoid glycosides and iridoid glycosides. The chemical structures of these compounds were determined as harpagoside (1), angoroside C (2), aucubin (3) and acetoside (4) based on spectroscopic analyses including nuclear magnetic resonance and MS. A simple and efficient HPLC with UV detection method for the simultaneous determination of the four compounds (1-4) has been developed and applied to their content determination in the S. buergeriana. The roots were extracted by 80% methanol, and the contents of 1, 2, 3, and 4 were determined to 11.5, 7.6, 41.2, and 4.8 mg/g, respectively. Additionally, angoroside C (2) and acetoside (4) exhibited hepatoprotective effect against ethanol-induced hepatotoxicity in HepG2 cell line.

• Korean Journal of Food Science and Technology
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• v.27 no.6
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• pp.827-833
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• 1995

Temperature distribution tests for a water cascading horizontal retort utilizing superheated water with overpressure as a heating medium were carried out under three different loading conditions, that is, empty(P-0), half-fully(P-3000) and fully(P-6000) loaded operating conditions. Tank volume and full loading capacity of sterilizer used for this study were about 5,900 liter and 1,140 kg(6000 pouches having 190 g weight each), respectively. Set point condition for sterilization was $122^{\circ}C$, 23 minutes and pressure was maintained in the range of $1.8{\sim}2.0\;kg/cm^2$ during sterilization. For each experiment, time-temperature data and F values were obtained from temperature microprocessor($F_0$ monitor). There were significant variations in the temperature distribution at different positions in the sterilizer. The temperature distribution was also affected by the pouch loading condition significantly. The application of the temperature distribution test to a product (retort pouched curry sauce) was conducted at the fully(P-6000) loading condition. Although heat transfer parameters($f_h\;and\;f_c$), and F values were varied with the position of sterilizer, sensory evaluation showed that the temperature distribution of the sterilizer used in this study didn't affect the quality of retorted curry sauce.

• KSBB Journal
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• v.13 no.6
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• pp.706-717
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• 1998

Enzymatic synthesis of fructose-based sugar fatty acid esters, such as methyl fructoside oleic acid mono and diester, was investigated using methyl fructoside as a sugar starting material. For the production of methyl fructoside fatty acid monoester by solvent process, 2-methyl 2-propanol was found to be a god reaction medium resulting a higher yield and productivity due to its high sugar solubility. The yield and productivity of methyl fructoside oleic acid monoester were 70% and 12.6g/L-hr, respectively, when molar ratio of methyl fructoside, initial concentration of methyl fructoside, enzyme(Novozym 435) content, and reaction temperature were 3:1, 200g/L, 1%(w/v), and $60^{\circ}C$, respectively. Methyl fructoside oleic acid diester was prepared by lipase-catalyzed diacylation of methyl fructoside and oleic acid in the solvent-free process. Maximum yield of 98% and productivity of 140g/L-hr were achieved when molar ratio(methyl fructoside and oleic acid) of 1:2 enzyme content of 10%(w/v) and reaction temperature of $70^{\circ}C$ were applied for the operating conditions under a reduced pressure of 20∼200 mmHg.

• Korean Chemical Engineering Research
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• v.43 no.1
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• pp.110-117
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• 2005

In this work, solid-state inclusion complex powders of itraconazole and $2-hydroxypropyl-{\beta}-cyclodextrin(HP-{\beta}-CD)$ were produced by a supercritical anti-solvent (SAS) process. In order to evaluate the degree of complexation, the thermal behavior of the microparticulate complexes was investigated using differential scanning calorimetry. The experimental results obtained for the solubility and dissolution rate of the microparticulate inclusion complexes in a buffer solution of pH 1.2 showed that the complexation of itraconazole with $HP-{\beta}-CD$ results in a significant increase in the solubility and dissolution rate of itraconazole. The particle size of the SAS-produced inclusion complexes was dramatically reduced ($<0.1-0.5{\mu}m$) compared with untreated itraconazole ($30-50{\mu}m$) and $HP-{\beta}-CD$ ($50-100{\mu}m$). The solubility of itraconazole was increased with the increase of pressure at a constant temperature to ca. $758.6{\mu}g/mL$ in an aqueous medium of pH 1.2. The dissolution rate of itraconazole was observed to be significantly improved and about 90% of itraconazole was found to be dissolved within 5-10 min.