• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3A
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• pp.383-390
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• 2008

A Precast Prefabricated Bridge Column using steel tube and prestressing bar was proposed for the application of precast method on substructure. A column specimen designed by the proposed bridge column system was made and performed a quasi-static test. The failure mode appeared to be a flexural failure and there is no damage on column segment connection. And it is good use of the self-centering ability by prestressing force. Test results showed that a column specimen satisfy the earthquake specification, and the structural stability was verified. Nonlinear finite element analysis was performed and compared with the test results. Force-displacement relation and location of crack from the analysis results were compared with the test results and it agreed well. The quantitative analysis was also performed by a parametric study using this modeling technique.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.43-44
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• 2023

This study evaluated the mechanical and electrical properties of low-cement mortar using a large amount of industrial by-products to reduce carbon emissions from the cement industry. As types of industrial by-products, blast furnace slag and fly ash, which are representative materials, were used, and ultra-high fly ash was mixed and evaluated to solve the problem of initial strength loss. In addition, in order to evaluate the electrical properties, 1% of MWCNT was incorporated relative to the powder mass. As experimental items, the compressive strength was measured on the 1st, 3rd, 7th and 28th days of age, and the rate of change in electrical resistance was measured on the 28th day of age. As a result of the experiment, the initial strength of the test specimen mixed with blast furnace slag and fly ash was significantly lower than that of 100% cement, and the specimen mixed with blast furnace slag showed strength equal to that of cement at 28 days of age. As an electrical characteristic, the electrical resistance was reduced when the load was loaded, and this reason is judged to be the effect of improving the conductivity as the connection between CNTs is narrowed by the compressive load.

• Korean Journal of Agricultural Science
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• v.15 no.1
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• pp.15-22
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• 1988

Factors affecting the regeneration, reversion of protoplasts from mycelium of F. velutipes were investigated and the selection of auxotrophic mutants from protoplasts of F. velutipes was performed. PDP medium stabilized with 0.6M sucrose was suitable for the regeneration of protoplasts, and regeneration frequency was 0.47-1.32. The regeneration frequency of protoplasts was increased when nutrients were added to the regeneration medium. Especially, yeast extract was the most effective to regeneration of protoplasts. Regeneration pattern of protoplasts was formation of germ tubes from bud-like cells. 13-18% of monokaryotic strains was appeared from reverted protoplasts. Five of auxotrophic mutants were isolated from strains showed survival frequency of 1.9-16.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.1
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• pp.91-99
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• 2008

A multilayer tower-type photoreactor, in which $TiO_2$-coated glass-tubes were installed, was used to measure the vapor-phase BTEX removal efficiencies by ozone oxidation ($O_3$/UV), photocatalytic oxidation ($TiO_2$/UV) and the combination of ozone and photocatalytic oxidation ($O_3/TiO_2$/UV) process, respectively. The experiments were conducted under various relative humidities, temperatures, ozone concentrations, gas flow rates and BTEX concentrations. As a result, the BTEX removal efficiency and the oxidation rate by $O_3/TiO_2$/UV system were highest, compared to $O_3$/UV and $TiO_2$/UV system. The $O_3/TiO_2$/UV system accelerated the low oxidation rate of low-concentration organic compounds and removed organic compounds to a large extent in a fixed volume of reactor in a short time. Therefore, $O_3/TiO_2$/UV system as a superimposed oxidation technology was developed to efficiently and economically treat refractory VOCs. Also, this study demonstrated feasibility of a technology to scale up a photoreactor from lab-scale to pilot-scale, which uses (i) a separated light-source chamber and a light distribution system, (ii) catalyst fixing to glass-tube media, and (iii) unit connection in series and/or parallel. The experimental results from $O_3/TiO_2$/UV system showed that (i) the highest BTEX removal efficiencies were obtained under relative humidity ranging from 50 to 55% and temperature ranging from 40 to $50^{\circ}C$, and (ii) the removal efficiencies linearly increased with ozone dosage and decreased with gas flow rate. When applying Langmuir-Hinshelwood model to $TiO_2$/UV and $O_3/TiO_2$/UV system, reaction rate constant for $O_3/TiO_2$/UV system was larger than that for $TiO_2$/UV system, however, it was found that adsorption constant for $O_3/TiO_2$/UV system was smaller than that for $TiO_2$/UV system due to competitive adsorption between organics and ozone.

• Applied Chemistry for Engineering
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• v.35 no.1
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• pp.54-60
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• 2024

The present study was aimed to evaluate the removal of the trace pollutants (heavy metals and microplastics) in the sewage treatment plant by using the jellyfish Extract at Immunity reaction (JEI) of Aurelia coerulea. The experiment was conducted on two different scales: the lab scale using a Jar-tester and the Pilot system scale equipped with two newly developed devices in the laboratory, the active tube connection mixed system and the concentration integrated separation device. Compared to anionic polymers currently used in the field, JEI showed similar or higher efficiency to remove the trace pollutants. When JEI was added to the effluent through the Pilot system, the combination of JEI and the trace pollutants was maximized through two mixing processes, and as a result, the removal rate of the trace pollutants was greatly improved. Based on these results, we propose the present technology as an alternative to removing trace pollutants that can reduce ecosystem risk and minimize the generation of inorganic waste, away from the existing method.

• The Journal of the Korea Contents Association
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• v.10 no.9
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• pp.267-275
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• 2010

Quality management of an x-ray unit drastically differs according to the type of establishment of medical institutions. Many primary medical institutions have it, but they do not pay much attention to quality management. In the study, Gyeongbuk area has been divided into four zones from January 4, 2010 to September 3, 2010, and four places were designated by city. Among medical institutions located at a total of 16 sites, the target was 8 places with X-ray emission equipment 10 years or more in use as well as 8 places with X-ray emission equipment less than 10 years in use. The 5 essential items of quality control were tested. In the test that checked for equipment it was found that sites with X-ray emission equipment 10 years or more in use didn't have ground connection (6.25%) while all of them passed the current leak test. In the exposure dose reproducibility test 4 sites with X-ray emission equipment 10 years or more in use (25%) and 1 site with X-ray emission equipment less than 10 years in use didn't pass the test. In the KVp accuracy test 5 sites with X-ray emission equipment 10 years or more in use (31.25%) and 2 sites with X-ray emission equipment less than 10 years in use (12.5%) didn't pass the test. In the tube current and tube current amount test 3 sites with X-ray emission equipment 10 years or more in use (18.75%) and 1 site with less than 10 years in use (6.25%) didn't pass the test. According to the findings of the present research, quality control at medical institutions with X-ray equipment 10 years or more in use was poorer than medical institutions with X-ray equipment less than 10 years in use. In this regard, administrative and technical measures need to be taken as soon as possible. In addition, owners of medical clinics or unit managers need to raise awareness, and it is necessary to revise a regular test cycle every year or every two years if they have old equipment or if the equipment is not used on a frequent basis. And it is also important to provide regular educational programs for quality management.

• Fire Science and Engineering
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• v.15 no.1
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• pp.23-33
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• 2001

The utility tunnels are the important facility as a mainstay of country because of the latest communication developments. However, the utilities tunnel is difficult to deal with in case of a fire accident. When a cable burns, the black smoke containing poisonous gas will be reduced. This black smoke goes into the tunnel, and makes it difficult to extinguish the fire. Therefore, when there was a fire in the utility tunnel, the central nerves of the country had been paralyzed, such as property damage, communication interruption, in addition to inconvenience for people. This paper is based on the fire occurred in the past, and reenacting the fire by making the real utilities tunnel model. The aim of this paper is the scientific analysis of the character image of the fire, and the verification of each fire protection system whether it works well after process of setting up a fire protection system in the utilities tunnel at a constant temperature. The fire experiment was equipped with the linear heat detector, the fire door, the connection water spray system and the ventilation system in the utilities tunnel. Fixed portion of an electric power supply cable was coated with a fire retardant coating, and a heating tube was covered with a fireproof. The result showed that the highest temperature was $932^{\circ}c$ and the linear heat detector was working at the constant temperature, and it pointed at the place of the fire on the receiving board, and Fixed portion of the electric power supply cable coated with the fire retardant coating did not work as the fireproof. The heating tube was covered with the fireproof about 30 minutes.

• Magazine of the Korean Society of Agricultural Engineers
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• v.13 no.2
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• pp.2262-2275
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• 1971

Fourteenes rervoirs maintained by the local land improvement associations in the province of Chullabuk-Do and 20 reservoir maintained by thos in the province of Chullanam-Do, were surveyed in connection with a correction between storage capacity and sediment deposit. In addition to this survey, 3,347 of small reservoir, that lie scattered around in the above-mentioned two provinces were investigated by using existing two provinces were investigated by using existing records pertaining to storage capacity in the office of City and country, respectively. According to this investigation the following comclusions are derived. 1. A sediment deposition rate is high, being about $10.63m^3/ha$ of drainage area, and resulting in the average decreasc of storage capaity by 27.5%. This high rate of deposition coule be mainly attributed to the serve denudation of forests due to disorderly cuttings of trees. Easpecially, in small reservoir, an original average design storage depth of 197mm in irrigation water depth is decreased to about 140mm. 2. An average unit storage depth of 325.6mm as the time of initial construction is decreased to 226mm at present. This phenomena causes a greater shortage irrigation water, since it was assumed that original storage quantity was already in short. 3. Generally speaking, seepage rates through dam abutment intakepipe, etc, are high due to insufficient maintenance and management of reservoir. 4. It is recommended that sediment deposit should be dredged when a reservoir is dry in drought. 5. Farmers usually waste excessive irrigation water. 6. Water saving methods should be practiced by applying only necessary water for growing stage of rice. 7. In are as where water defficiency for irrigation is severe, a soil moisture content should be kept at about 70% by applying water once in several days. 8. Tube wells should be provided so as to exploit ground water and subsurface current below stream bed as much as possible. 9. If an intake weir was constructed, a water collection well should be built for the use in drought. 10. Water conservation should be forced by converting devastated forests contained in the drainage area of reservoir to protected forests so as to take priority of yrefor estation, gully control, the prohibition of disorderly cutting of trees, etc. 11. Collective rice nurseries should be adopted, and it should be recommended that irrigation water for rice nurseries is supplied by farmer themselves. 12. Sediment desposit in reservoir should be thoroughly dreged so as to secure a original design storage capacity. 13. The structure of overflow weir should be automatic so as to freely control flood level and not to increase dam height.

• Journal of Chest Surgery
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• v.32 no.7
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• pp.621-627
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• 1999

Background: Sixty five cases with congenitally corrected transposition of the great arteries (CCTGA) indicated for biventricular repair were operated on between 1984 and september 1998. Comparison between the results of the conventional(classic) connection(LV-PA) and the anatomic repair was done. Material and Method: Retrospective review was carried out based on the medical records of the patients. Operative procedures, complications and the long-term results accoding to the combining anomalies were analysed. Result: Mean age was 5.5$\pm$4.8 years(range, 2 months to 18years). Thirty nine were male and 26 were female. Situs solitus {S,L,L} was in 53 and situs inversus{I,D,D} in 12. There was no left ventricular outflow tract obstruction(LVOTO) in 13(20%) cases. The LVOTO was resulted from pulmonary stenosis(PS) in 26(40%)patients and from pulmonary atresia(PA) in 26(40%) patients. Twenty-five(38.5%) patients had tricuspid valve regurgitation(TR) greater than the mild degree that was present preoperatively. Twenty two patients previously underwent 24 systemic- pulmonary shunts previously. In the 13 patients without LVOTO, 7 simple closure of VSD or ASD, 3 tricuspid valve replacements(TVR), and 3 anatomic corrections(3 double switch operations: 1 Senning+ Rastelli, 1 Senning+REV-type, and 1 Senning+Arterial switch opera tion) were performed. As to the 26 patients with CCTGA+VSD or ASD+LVOTO(PS), 24 classic repairs and 2 double switch operations(1 Senning+Rastelli, 1 Mustard+REV-type) were done. In the 26 cases with CCTGA+VSD+LVOTO(PA), 19 classic repairs(18 Rastelli, 1 REV-type), and 7 double switch operations(7 Senning+Rastelli) were done. The degree of tricuspid regurgitation increased during the follow-up periods from 1.3$\pm$1.4 to 2.2$\pm$1.0 in the classic repair group(p<0.05), but not in the double switch group. Two patients had complete AV block preoperatively, and additional 7(10.8%) had newly developed complete AV block after the operation. Other complications were recurrent LVOTO(10), thromboembolism(4), persistent chest tube drainage over 2 weeks(4), chylothorax(3), bleeding(3), acute renal failure(2), and mediastinitis(2). Mean follow-up was 54$\pm$49 months(0-177 months). Thirteen patients died after the operation(operative mortality rate: 20.0%(13/65)), and there were 3 additional deaths during the follow up period(overall mortality: 24.6%(16/65)). The operative mortality in patients underwent anatomic repair was 33.3%(4/12). The actuarial survival rates at 1, 5, and 10 years were 75.0$\pm$5.6%, 75.0$\pm$5.6%, and 69.2$\pm$7.6%. Common causes of death were low cardiac output syndrome(8) and heart failure from TR(5). Conclusion: Although our study could not demonstrate the superiority of each classic or anatomic repair, we found that the anatomic repair has a merit of preventing the deterioration of tricuspid valve regurgitations. Meticulous selection of the patients and longer follow-up terms are mandatory to establish the selective advantages of both strategies.