• 대한공업교육학회지
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• v.33 no.1
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• pp.191-212
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• 2008

The purpose of this study was to show how to organize small groups on the project method class in technical high school. The subjects of this study were two classes including 40 second-year students (20 students in each class) of architecture design course in D technical high school located in Taejeon metropolitan city. The method of this study was to investigate the ego-state by the ego-gram practicing Transactional Analysis. Total 10 small groups were organized. Each group had 4 members. And the same quality of egostate small group was organized by the 4 students who have high score on NP and AC. The different in kind small group was organized by the 4 students, each of whom has NP leading, A leading, FC leading and AC leading score. After the target small group was video- taped, students' verbal interaction was written into transcripts. Their individual states were analysed by the frame of verbal interaction. The result of this study was that the same quality of TAOK small group had more active interaction(110 times) than different in kind small group(87 times). The frequency of complementary transaction was also higher plenty in the same quality of TAOK small group.

• Progress in Superconductivity and Cryogenics
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• v.19 no.1
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• pp.30-35
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• 2017

The effects of the crystallographic orientation and sample thickness on the magnetic levitation forces (F) and trapped magnetic field (B) of single grain YBCO bulk superconductors were examined. Single grain YBCO samples with a (001), (110) or (100) surface were used as the test samples. The samples used for the force-distance (F-d) measurement were cooled at 77 K without a magnetic field (zero field cooling, ZFC), whereas the samples used for the B measurement were cooled under the external magnetic field of a Nd-B-Fe permanent magnet (field cooling, FC). It was found that F and B of the (001) surface were higher than those of the (110) or (100) surface, which is attributed to the higher critical current density ($J_c$) of the (001) surface. For the (001) samples with t=5-18 mm, the maximum magnetic levitation forces ($F_{max}s$) of the ZFC samples were larger than 40 N. About 80% of the applied magnetic field was trapped in the FC samples. However, the F and B decreased rapidly as t decreased below 5 mm. There exists a critical sample thickness (t=5 mm for the experimental condition of this study) for maintaining the large levitation/trapping properties, which is dependent on the material properties and magnitude of the external magnetic fields.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.3
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• pp.67-76
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• 2019

The objectives of this study were to analyze trends of water pollutants and to evaluate the achievement of water quality standards by subbasins in the Han River. The trends of 40 water pollutants at 232 water quality measurement points were analyzed. Chemical oxygen demand (COD), Total organic carbon (TOC), Total coliforms (TC), et cetera were found to be worsening trend. For evaluation of achievement, we evaluated water quality arithmetic mean with river environment standards and human health standards at representative points of the subbasin. Biochemical oxygen demand (BOD), TOC, Total phosphorus (T-P), Fecal coliforms (FC), TC exceeded water quality standards, and water quality of human health standards was all satisfied. So, we prioritized pollutants. If pollutants exceed water quality standards or were worse, they were classified first pollutants. Although BOD and T-P are first pollutants because of water quality standards excess, they are continuously improved. Also, it is better to maintain current status because water quality management system of BOD and T-P is well prepared. Meanwhile, TOC, TC, and FC exceed water quality standards. Furthermore, they were worse gradually, but there is a lack of management systems such as water quality standards of the effluence facilities. Therefore, it is necessary to supplement the system. The results of this study can be used as primary data for the establishment of water quality standards and selection of management pollutants.

• Journal of Applied Biological Chemistry
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• v.57 no.3
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• pp.197-203
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• 2014

Various parameters such as solvent selection, concentration, solid/liquid ratio, soaking time, temperature, stationary, shaking conditions, and repeated extractions were investigated in order to determine the optimum extraction conditions of ${\beta}$-glucosidase from bagasse fermented by mixed culture of Aspergillus niger NRC 7A and Aspergillus oryzae NRRL 447. Among various solvents tested, non ionic detergents gave the best results than the inorganic or organic salt solutions and distilled water. The optimum conditions for extraction of ${\beta}$-glucosidase were 30 min soaking time at $40^{\circ}C$ under shaking condition at 150 rpm, with solid/liquid ratio 1:15 (w/v), which yielded $2882.74{\pm}95.52U/g$ fermented culture (g fc) of enzyme activity. With repeated washes under the above optimum conditions, the results showed that enzyme extracted in the $1^{st}$ and $2^{nd}$ washes represents about 90% of the total activity.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.317-320
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• 2000

Effects of supplementing various 0.1-1.0%(w/v) surfactants and 0.1-1.0%(v/v) oxygen vectors on postthaw growth following cryopreservation of transgenic Nicotiana tabacum(GUS) in suspension culture were investigated. The postthaw cell growth was increased 20.68% and 23.66% compared to control when Pluronic F-68 and polyethylene glycol(PEG) were added in recovery medium respectively. Addition of n-hexadecane and FC-40 also enhanced the recovered growth by 14.89% and 20.68%. These results demonstrate that the marked Protection could be achieved by using surfactants and oxygen vectors for plant cells recovered from cryostorage.

• Journal of Environmental Health Sciences
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• v.13 no.1
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• pp.35-40
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• 1987

Personal computer based measurement and control system was constructed and tested in order to fiexibly apply it to laboratoy experiments in which environmental factors such as temperature, humidity, pH, DO and gases should be measured and controlled. Personal computer FC-80 was successively interfaced to the input-output system made up of PPI, A/D converter, D/A converter, programmable timer and USART boards. To test the system, pH control experiment was executed and the pH of the solution could be measured, expressed on the monitor and controlled at constant value.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.4
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• pp.629-636
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• 1987

An experiment is carried out to study the surface-tension driven flow characteristics in a cylindrical liquid column heated from above (which is the low gravity floating zone simulated on earth) with varing the aspect ratio and diameter of the liquid column. Hexadecane, octadecane, silicon oil(10cs), FC-40 and water are used as the test liquids. The free surface shape varies sinusoidally for Ma>M $a_{cr}$ and its frequency is found to be the same as that of temperature oscillation. It is verified that the surface temperature profile changes from linear to S-shaped profile for Ma>M $a_{cr}$ . The frequency of temperature oscillation decreases with increasing liquid volume, while its level increases. M $a_{cr}$ decreases with increasing aspect ratio, and also decreases with increasing Prandtl number in the range of 25

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2369-2374
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• 2008

In the precision hot plate for wafer processing, the temperature uniformity of upper plate surface is one of the key factors affecting the quality of wafers. Precision hot plates require temperature variations less than ${\pm}1.5%$ during heating to $120^{\circ}C$. In this study, we have manufactured the flat plate heat pipe hot chuck of circle type(300mm) and investigated the operating characteristics of flat plate heat pipe hot chuck experimentally. Various liquids(aceton, FC-40, water) were used as the working fluid and charging ratio was changed($14{\sim}36\;vol.%$). Several cases were tested to improve temperature uniformity. Major working fluid to be investigated was water. Using water, various parameters such as charging ratio, wafer operation on-off time, different working fluids. In case of water, the temperature uniformity was ${\pm}1.5%$, response time of wafer were investigated.

• Journal of Embryo Transfer
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• v.20 no.1
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• pp.35-41
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• 2005

This study was carried out for development of effective preservation on animal genetic resources. Spermatogonia cells are the germline stem cells and they can be restored to adult animal with proliferation and differentiation intentionally. When the spermatogonia cells were purified from seminiferous tubules and were cultured at $32^{\circ}C$, the cells were actively proliferated. The culture medium consisted of TCM199 plus $10\%$ FCS and coculture with Sertoli cells supported cultivation of spermatogonia cells. By passing 40 days of incubation, spermatogonia cells formed the germline colony or shape of ES-like colony or reconstruction of pseudo-seminifcrous tubule shape. At 40 days, the cultured cells were no sign for differentiation to spermatocyte or spermatid. The experiment of induced differentiation of this cells is needed.

• Journal of Advanced Navigation Technology
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• v.22 no.1
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• pp.27-30
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• 2018

In this study, a 40 GHz band pass filter(BPF) employing a hair-pin structure has been designed, fabricated, and characterized for millimeter-wave wireless communication applications. Using the 3 dimensional(3-D) electromagnetic(EM) tool and design equations of the hairpin BPF, the BPF was desgned on the 5 mil-thick Duroid substrate(RT5880) with a relative dielectric constant (${\varepsilon}_r$) of 2.2. The tapping point (t) of the U-shape resonator in the input and output port has been determined using extracted an external Q-factor ($Q_e$). The coupling coefficients between the other resonators are calculated by adjusting the physical dimensions for the desired response of the BPF. The fabricated BPF was characterized using probing method on a probe station. Its measured center frequency(fc) and fractional BW are 41.6 GHz and 7.43 %, respectively. The measured return loss is below -10 dB at the pass band and the insertion loss is 3.87 dB. The fabricated BPF is as small as $9.1{\times}2.8mm^2$.