• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.12
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• pp.142-148
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• 1995

Sb ${\delta}$-doped Si layers were grown by Si MBE (Molecular Beam Epitaxy) system using substrate temperature modulation technique. The Si substrate temperatures were modulated between 350$^{\circ}C$ and 600$^{\circ}C$. The doping profile was as narrow as 41$\AA$ and the doping concentration of up to 3.5${\times}10^{20}cm^{3}$ was obtained. The film quality was as good as bulk material as verified by RHEED (Reflected High Energy Electron Diffraction), SRP (Spreading Resistance Profiling) and Hall measurement. Since the film quality is not degraded after the growth a Sb ${\delta}$-doped Si layer, the ${\delta}$-doped layers can be repeated as many times as we want. The doping technique is useful for many Si devices including small scale devices and those which utilize quantum mechanical effects.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2003.08a
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• pp.353-358
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• 2003

As fur quantitative evaluation of the amount of sediments released into the ambient waters by various works fur coastal development, the instrument and method of the measurement of suspended sediment concentration (SSC) are critical for estimating the efficiency of a silt screen to reduce the spreading of sediment plumes generated by coastal works. (omitted)

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.3
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• pp.46-55
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• 1998

This stud demonstrates the profiles of heavy ions (As, Sb) in silicon by high energy (1~10 MeV) implantation. Implanted profiles were measured by SIMS (Cameca 4f) and compared with simulation results (TRIM) program and analytical description method using Pearson function). The experimental results have a little bit deviation with simulation data in the case of As high energy implatation. But in the case of Sb, the experimental results are in good agreement with TRIM data. SIMS profiles are perfectly fitted with a analytical description method only using one pearson function in Sb implantation. but in the case of As, fitted profilesshow with a little bit deviations by channeling effects of SIMS profiles. Thermal annealing for electrical activation of implanted ions was carried out by furnace annealing and RTA(Rapid Thermal Annealing). Concentration-depth profile after heat treatement were measured by SR(Spreading Resistance) method.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.11 no.3
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• pp.219-228
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• 2001

Objective : For the purpose of preparing the fundamental data and health promotion and control program on organic solvents in air of manufacturing industry. Methods : The author surveyed number of organic solvent components which was used in working site and also determined the organic solvents concentration in air of 927 manufacturing industries and 1,267 working process with gas chromatography(NIOSH manual) for five years from 1995 to 1999. Results : Mean number of solvents components by type of industry, working process was number of 12. There were exceeded to TLV of 1,2-dichloroethane in textile manufacturing industry N,N-dimethyl furan in tanning and dressing of leather ; luggage, handbags, saddlery, harness and footwear manufacturing industry and chemical and chemical product manufacturing industry by type of industry. There were exceeded to TLV of 1,2-dichloroethane in handwriting and drawing process, cellosolve in adhesive spreading process, N,N-dimethly furan in production of solvent process and adhesion process by working process Total exceeded rate to threshold limit values of organic solvents mixture were 12.9% for EI(Exposure index) and 10.0% for Em(Estimation of mixture) by type of industry, 11.3% for EI and 8.2% for Em by type of working process. The highest exceed rate was 36.7% for EI in tanning and dressing of leather ; luggage handbags, saddlery, harness and footwear manufacturing industry and 29.0% for Em in textile manufacturing industry. The highest exceeded rate was 23.1% for EI and 12.5% for Em in adhesive spreading process by working process. Mean values of total subjects by type of industry and type of working process were $0.7{\pm}1.8$ for EI and $0.7{\pm}1.7$ for Em respectively. Conclusions : As above results, the author suggest that it makes the environmental control program on 1.2-dichloroethane, N,N-dimethyl furan, cellosolve by kind of organic solvent and on textile manufacturing industry, tanning and dressing of leather ; luggage, handbags, saddlery harness and footwear manufacturing industry by type of industry, and on handwriting, drawing process and adhesive spreading process and adhesion process by type of working process.

• Korean Journal of Soil Science and Fertilizer
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• v.51 no.2
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• pp.119-127
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• 2018

Veterinary antibiotics (VAs) has been used to treat animal disease and to increase body weight. However, released VAs in the soil via spreading of compost can transport to plant and affect its growth. Main purpose of this research was i) to monitor VAs concentration in plant and ii) to evaluate inhibition effect of VAs residuals on the plant growth. Red lettuce (Lactuca sativa) was cultivated for 35 days in the pot soil spiked with 3 different concertation (0.05, 0.5, $5.0mg\;kg^{-1}$) of chlortetracycline (CTC) and sulfamethazine (SMZ). After 35 days of cultivation, concentration of CTC and SMZ in the plant was measured. Residual of CTC and SMZ was only quantified at the range of $0.007-0.008mg\;kg^{-1}$ and $0.006-0.017mg\;kg^{-1}$ in the leaf and root respectively when high concentration ($5.0mg\;kg^{-1}$) of antibiotic was spiked in the soil. Leaf length and root mass was statistically reduced when $0.05mg\;kg^{-1}$ of CTC was spiked in the soil while no statistical difference was observed for SMZ treatment. This result might indicated that high $K_{ow}$ and $K_d$ value are the main parameters for inhibiting plant growth. Antibiotics that has a high $K_{ow}$ causing hydrophobicity and easy to bioaccumulate in the lipid cell membrane. Also, antibiotics that has a high $K_d$ properties can be sorbed in the root causing growth inhibition of the plant. Overall, management of VAs should be conducted to minimize adverse effect of VAs in the ecosystem.

• Earthquakes and Structures
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• v.17 no.2
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• pp.163-173
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• 2019

For Special Concentrically Braced Frame (SCBF), it is common that the damage concentrates at a certain story instead of spreading over all stories. Once the damage occurs, the soft-story mechanism is likely to take place and possibly to result in the failure of the whole system with more damage accumulation. In this study, we use a strongback column which is an additional structural component extending along the height of the building, to redistribute the excessive deformation of SCBF and activate more structural members to dissipate energy and thus avoid damage concentration and improve the seismic performance of SCBF. We tested one-third-scaled, three-story, double-story X SCBF specimens with static cyclic loading procedure. Three specimens, namely S73, S42 and S0, which represent different combinations of stiffness and strength factors ${\alpha}$ and ${\beta}$ for the strongback columns, were designed based on results of numerical simulations. Specimens S73 and S42 were the specimens with the strongback columns, and S0 is the specimen without the strongback column. Test results show that the deformation distribution of Specimen S73 is more uniform and more brace members in three stories perform nonlinearly. Comparing Drift Concentration Factor (DCF), we can observe 29% and 11% improvement in Specimen S73 and S42, respectively. This improvement increases the nonlinear demand of the third-story braces and reduces that of the first-story braces where the demand used to be excessive, and, therefore, postpones the rupture of the first-story braces and enhances the ductility and energy dissipation capacity of the whole SCBF system.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.6
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• pp.23-30
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• 2018

Gordon Cullen, who tried to understand urban landscapes in terms of visual attention, introduced a concept called 'Space and Infinity' in his book 'Townscape'. According to him, urban images like infinity spreading across the sky are more effectively created when we happen to see an open space while walking along a ground-level street than when we look at the sky. This study aims to quantitatively examine if urban observers pay more attention to spaces like pilotis on the bottom of a building. Thus, this study collected observers on actual urban landscape images and partially-edited images and conducted an experiment by adopting Eye-movement Tracking to find out if they actually pay more visual attention to a space like pilotis. This study selected a total of 50 people as research subjects and divided them into two groups. Image 1 was shown to one group, and Image 2 with the pilotis space edited was shown to the other group. As an experiment to find objective evidences on Gordon Cullen's 'Space and Infinity', this study analyzed difference between Image 1 and Image 2, and it was found that the domain of pilotis showed a value five times higher than the average visual attention since it attracted much visual attention although it was very small in area. That is, it has objectively clarified that people get most fascinated with a place with infinite images in the background like a pilotis space out of all the urban landscapes as Gordon Cullen's theory. In addition, the differences in visual concentration of pilotis space by sex, by subject was examined, and there was no significant difference in visual concentration of pilotis space by gender. As a result of examining the difference of visual concentration by classifying the subjects into architectural related major, the major group showed higher frequency of viewing than the non - major group.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.6
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• pp.609-617
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• 2012

The impact, spreading and recoil processes of a nanoparticle-laden droplet impacting on a horizontal solid surface are numerically investigated by solving the conservation equations for mass, momentum, energy and mass fraction. The liquid-air interface is tracked using a level-set method that is modified to include the effect of contact angle hysteresis at the wall. The species transport equation including a thermal diffusion term is additionaly solved to determine the nanoparticle distribution in the droplet. The effect of nanoparticle concentration and contact angle are also studied.

• Korean Journal of Environmental Agriculture
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• v.28 no.4
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• pp.435-441
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• 2009

In the present study, we analyzed the defensin protein deduced from Korean radish (Raphanus sativus L.) seeds.To express the genes in E. coli, we constructed a recombinant expression vector with a defensin gene, named rKRs-AFP gene isolated from Korean radish seeds. Over expressed rKRs-AFP proteins was separated by SDS-PAGE to determine the purity, and protein concentration was determined by the Bradford method. Antifungal activity was assessed by disk assay method against the tested fungi. As a result, when 500 mL of cell culture were disrupted by sonicator, 32.5 mg total proteins were obtained. The purified protein showed a single band on SDS-PAGE with estimated molecular weight about 6 KDa, consistent with the molecular mass calculated from the deduced amino acid sequence. The purified rKRs-AFP protein showed remarkable antifungal activities against several fungi including Aspergillus niger, Botrytis cinerea causing the gray mold disease, and Candida albicans. In field tests using the purified rKRs-AFP protein, the protein showed the reducing activity of disease spot and the mitigating effect of spreading of disease like agrichemicals. The immuno-assay of rKRs-AFP protein showed that the purified protein entirely accumulated at B. cinerea cytoplasm through the hyphal septa shown by fluorescence imaging. There was no fluorescence inside the cell, when the hypha was incubated without the protein. These all results indicate that the recombinant rKRs-AFP proteins can be utilized as a potential antifungal drug to control harmful plant fungal pathogens.

• Environmental Engineering Research
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• v.22 no.1
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• pp.55-60
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• 2017

Provision of safe, accessible, and good water quality in the community is an important step towards reducing various waterborne illnesses. However, improving the quality of water should include spreading awareness to the public regarding the importance of cleaning their household water tanks. The aim of this study was to investigate the microbial quality of water of household water tanks in Dubai. The water samples from household water tanks were collected from forty houses, and a questionnaire was given to the residents to determine the history of the water tanks. The membrane filtration technique was used to quantify heterotrophic and total coliform bacteria on plate count agar and the violet red bile agar respectively. The overall results of this study have shown that 18 out of total 40 household water tanks contained different types of bacteria concentration level beyond local and widely accepted international standards. The overall results of this study indicated that there is a lack of awareness among residents regarding the importance of maintaining proper sanitation and hygiene of the household water tanks.