• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.9
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• pp.754-760
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• 2008

A two-photon induced photoreduction process suggests a possibility for fabricating complicated metallic microstructures which can be applied to 3-D micro-circuits and optical devices, etc. The process employs the photoreduction of silver ions in a metallic solution which is composed of metallic salt ($AgNO_3$) and watersoluble polymer ((poly(4-styrenesulfonique acid) 18wt. % in $H_2O$, $(C_8H_8O_3S)_n$)). In this process, the improvement of the resolution and the uniformity of fabricated metallic structures are important issues. To address these problems, continuous forming window (CFW) is obtained from a parametric study on the conditions of laser power and scanning velocity and the direct seed generation (DSG) method is proposed. Silver nano particles are uniformly generated in a metallic solution through the DSG method, which enables the decrease of a laser power to trigger the photoreduction of silver ions as well as the increase of metal contents in a metallic solution. So the two-photon induced photoreduction property of a metallic solution is improved. Through this work, precise silver patterns are fabricated with a minimum line width of 400 nm.

• Food Science and Biotechnology
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• v.15 no.6
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• pp.866-870
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• 2006

The maintenance of physiological activity during dilution is very critical for the accurate enumeration of Vibrio spp. in marine samples. We investigated the effect of various diluents on the recovery of Vibrio parahaemolyticus using the direct plate counting and most probable number (MPN) methods. The effects of NaCl (0.85 and 3%) and pH (from 6.6 to 7.4) in diluents based on distilled water or phosphate buffered saline (PBS) were evaluated with three V. parahaemolyticus strains. PBS-3% NaCl (pH 6.6), as opposed to PBS, was the most effective diluent at maintaining viable cell numbers up to 2 log CFU/g during dilution for direct plate counting using on thiosulfate citrate bile salts sucrose (TCBS) selective agar, as well as minimizing the difference in cell numbers between TCBS and non-selective nutrient agar. It also increased counts of V parahaemolyticus inoculated into oysters relative to PBS (p<0.01), suggesting that PBS-3% NaCl (PH 6.6) can reduce the problem of underestimating V. parhaemolyticus counts using PBS alone.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.455-458
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• 2003

A combination of drilling, hydrogeochemical survey, geophysical survey and the numerical modelling for the flow and transport of groundwater was performed to evaluate the seawater intrusion in Baeksu-eup, Yeonggwang-gun, Korea. The survey area extends to over 24 $km^2$. Twelve wells were also drilled for the collection of geologic, geochemical, hydrologic, and geophysical logging data to delineate the degree and vertical extent of seawater intrusion. To evaluate and map the salinity in a coastal aquifer, geophysical data and hydrogeochemical results were used. Layer parameters derived from VES data, various in situ physical properties from geophysical well loggings, and the estimated equivalent NaCl concentration were used as the useful input parameters for the numerical simulation with density-dependent flow. Our multidisciplinary approach for evaluating the seawater intrusion can be considered as a valuable attempt to enhancing the utilization of various data and the reliability of numerical ground modelling.

• Journal of Korean Society on Water Environment
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• v.30 no.3
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• pp.304-310
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• 2014

The conventional methods for total residual chlorine such as iodometry and DPD colorimetric can cause secondary pollution due to additional agents, also have a wide error range. As for alternative, electrochemical method can measure TRC(Total residual chlorine), and is not required as additional agents, also very suitable for using the fields of ballast water because test time is relatively fast. Therefore, this study was investigated for changing charge by agitation, salt concentration, and temperature change. Charge showed differences based on changes of reduction peak with or without agitation. In contrast, TRC and charge were well correlated in constant agitation speed. As TRC and charge were analyzed with high correlations in constant salinity and temperature of ocean, thereby conductivity was firstly measured, and charge had high correlation for TRC in spite of changing salinity and temperature Pt electrode revealed high reliability ($r^2=0.960$) because it was rarely effected by TRC, On the other hand, Au electrode appeared inadequate ($r^2=0.767$) to use sensor in less than 1.0 ppm of TRC. For high accuracy and detection of TRC, Pt and Au electrodes for test time were, respectively, 14 and 22 seconds. As a result, Pt electrode was more valuable than Au electrode in terms of response time.

• Korean journal of food and cookery science
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• v.12 no.3
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• pp.280-290
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• 1996

The suwey on the consumption pattern of Korean traditional soy sauce and commercial soy sauce was performed. 55.8 percentage of surveyed house makes Korean traditional soy sauce domestically, But its frequency in actual use is lower than commercial soy sauce. The use of Korean traditional soy sauce and commercial soy sauce was different depending on the kinds of food. Korean traditional soy sauce is mainly used for kinds of soup, and commercial soy sauce is predominantly used for hard-boiled foods and Chapchae. Korean traditional soy sauce is known as our typical fermented food and has special flavor. But its main factors of special flavor were not well established yet. So the authors have investigated the main components of Korean traditional soy sauce for its typical taste. Five samples o$.$ere selected from'Kyung-ln'area. The sensory charac teristics of Korean traditional soy sauce itself were very different with that of cooked food added with Korean traditional soy sauce. The hard-boiled mackerel cooked with commercial soy sauce was prefered than Korean traditional soy sauce. And soups and seasoned vegetables cooked with Korean traditional soy sauce were profered. By stepwiEe regression analysis and correlation analysis, sensory overall acceptability mainly depends on specific gravity, salt content and amino nitrogen content (R'=0.94). And total nitrogen content was highly coirelated with overall acceptability (r=0.91).

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.10a
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• pp.246-252
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• 2000

The water quality in Yeongil Bay is getting worse due to the sewage and the waste water from the surrounding industrial complex The study aims to simulate the current system that is necessary to built ecosystem model for the optium water quality control and clarify the correlation of current system characteristics with water quality in Yongil Bay. To clarify the characteristics of coastal water movement system and verify the applicability of the 3-D model, the current system was simulated using 3-D baroclinic model considered tidal current and density effects. As the results of numerical experiments, it is proved the 3-D model is the most appliable on the Yongil Bay where current flows slowly and the flow direction is varied by depths. From the results of simulation considered tidal current only, It am be clearly said the water in Yongil Bay flows in through the surface layer and flows out through the bottom layer. And the fresh water from the Hyongsan river and the heated discharge from POSCO have little effect on the current structure in Yonggil Bay, but have and important effect upon the density structure by diffusion of heat and salt. And the water quality distribution is closely related with the current structure characteristics as well as the tidal residual current system.

• Journal of the Korean Geotechnical Society
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• v.18 no.6
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• pp.83-101
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• 2002

Elastic waves provide an important information about the soil mass in the near-surface. Soil properties in relation to elastic wave parameters are clarified to facilitate the application of geophysical technique to soil characterization. As an example, experiments are performed to gain further insight into the behavior of unsaturated particulate materials using bender elements. The small strain stiffness is continuously measured on specimens subjected to drying, and changes in stiffness are related to changes in interparticle forces such as capillarity, bonding due to ion sharing, buttress effect due to fine migration, and cementation due to salt precipitation. The rate of menisci regeneration is studied after a perturbation as well. Finally, several phenomena associated with the evolution of capillary forces during drying are identified.

• Journal of the Korean Applied Science and Technology
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• v.32 no.4
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• pp.631-638
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• 2015

In Korea, yam with thermal treatment is widely used to produce tea and beverage, which appeals to all age groups. To better understand the antioxidative activity of thermal treatment yam (Dioscorea batatas $D_{ECNE.}$), n-butanol and ethyl acetate extracts were evaluated with different antioxidant testing system. Their antioxidant activities, including ABTS [2,2' -azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt] radical scavenging activity, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, reducing power, and ferric reducing antioxidant power as well as total phenol contents were assessed in vitro. Results showed ethyl acetate extract ($51.63{\pm}2.51mg\;CAE/g$) possessed similar total phenol content compared with n-butanol extract ($53.93{\pm}1.00mg\;CAE/g$). Ethyl acetate extract also exhibited similarly stronger antioxidant activity compared with n-butanol extract apart from ABTS radical scavenging activity assay.

• Journal of the Korean Applied Science and Technology
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• v.32 no.4
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• pp.599-606
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• 2015

This study aimed at evaluating the antioxidant activity of raw yam (Dioscorea batatas $D_{ECNE.}$) extracted by n-butanol and ethyl acetate. The antioxidant activities, including ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt] radical scavenging activity, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, reducing power, and ferric reducing antioxidant power as well as total phenol contents were studied in vitro. Results showed ethyl acetate extract ($111.88{\pm}0.66mg\;CAE/g$) possessed higher total phenol content than n-butanol extract ($78.68{\pm}0.58mg\;CAE/g$). Ethyl acetate extract exhibited stronger antioxidant activity compared with n-butanol extract apart from reducing power assay.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.2
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• pp.157-166
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• 2006

Ambient TSP at four sites in Korea and soil samples from the source regions of Asian Dust in northern China were collected and analyzed for 15 metal components and 6 water-soluble ions to conduct a chemical mass balance (CMB). CMB receptor model was used to estimate the source contribution of TSP during the Asian Dust period, and the model results showed that China soil was the largest source contributor, accounting for 81% of TSP ($458.2{\mu}g/m^3$). Vehicle emission and geological sources contributed to about 8.8% and 4.4% of aerosol mass, followed by sea salt (1.5%) and secondary aerosol (2.9%). Fuel combustion and industrial process sources were found to be relatively minor contributors to TSP (${\leq}1%$). In addition to source contribution estimates, this study tried to identify the origin of Asian Dust observed in Korea. Among all 13 China soil profiles presented in this study, the most adoptable profile which can project the case well was selected and considered as the origin of the applied case.