• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.3
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• pp.201-209
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• 2004

Important operation parameters and performance of a high temperature ceramic candle filter system were evaluated through a series of demonstration tests at a pilot-scale vitrification plant. At the initial period of each test, due to the growth of dust cake on the surface of ceramic candles, the pressure drop across the filter media increased sharply. After that it became stable to a certain range and varied continuously proportion to the face velocity of off-gas. On the contrary, at the initial period of each test, the permeability of filter element decreased rapidly and then it became stable. Back flushing of the filter system was effective under the back flushing air pressure range of 3∼5 bar. Based on the dust concentrations measured by iso-kinetic dust sampling at the inlet and outlet point of HTF, the dust collection efficiency of HTF evaluated. The result met the designed performance value of 99.9%. During the demonstration tests including a hundred hour long test, no specific failure or problem affecting the performance of HTF system were observed.

• Journal of radiological science and technology
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• v.38 no.4
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• pp.355-363
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• 2015

Advancement in the medical field provides an opportunity for the development of medical equipment and also enable accurate diagnosis for the inspection and the treatment of diseases. The aging of equipment due to the frequent operation produce uncertainty in the patient exposure dose, so a quality control was implemented by establishing a safety management system on a regular basis. The x-ray tube voltage (kVp), which is directly involved in the patient exposure dose and the life of the equipment, needs periodic performance for the quality control, but it has a limitation due to the time and the cost. In this study, we proposed a new method for measuring the kVp with ease by using the Y and Cu to solve the problem of the time and cost. We also evaluated the usefulness and the effectiveness of the new method and its accuracy through the kVp measurement. After securing the condition, the amount of the tube current and evaluating the usefulness and effectiveness of kVp measured using Y and Cu. The density range used was at 0.5-1.0, kVp was in the range of ${\pm}10%$, then, we recorded the change in concentration as % of Y and Cu. This experiment showed that when Cu and Y was at 75 kVp, concentration was the same, and when the kVp was changed to 65 ~ 85 %, a gradual increase in concentration to 85 ~ 110 % was noted.

• Journal of Korean Society of Transportation
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• v.21 no.1
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• pp.7-19
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• 2003

The airspace has to be designed considering the flight safety and economic efficiency of aircraft operators. The International Civil Aviation Organization(ICAO) published standards and recommended practices for safe design of the airspace. Each contracting country must follow the ICAO standards in designing the airspace for the utilization of civil aviation. Normally each member establishes its own standards and national aviation law for the safe and efficient design of the airspace, regarding the ICAO standards. However, our government has not developed yet clear and detailed standards and regulation system for airspace design. This might lead to aviation accidents and disputes between operators of aviation system This study is to review the characteristics of ICAO standards and a legal problem related to application of international standards for airspace design. Specifically this research analyzed the case of airspace design and operation of a domestic airport. The results of analysis are as follow: (1) per the safety of civil aviation, it is very required to establish national regulation system to follow ICAO standards in designing airspace, (2) It is also necessary to establish separate procedure for civil aircraft in military air base, when the aerodrome is co-used by military and civil aircraft. If the same procedure for military aircraft is applied to civil aircraft, it is necessary to make clear what the design concept is, (3) and the differences from ICAO standards have to be publicly known.

• Journal of Chest Surgery
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• v.16 no.2
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• pp.139-146
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• 1983

Between 1974 and 1982, 31 patients from 7 to 15 years of age have undergone valve replacement for their acuqired cardiac valvular diseases at Seoul National University Hospital. Furteen patients (45.2%) had a definite history of rheumatic fever and only 4 patients (12.9%) had atrial fibrillation on their preoperative electrocardiograms. Characteristically, the valvular lesions were ones of insufficiency with or without associated stenosis in all patients except only one whose mitral valve was tightly stenotic. Thrity-seven valves were replaced in 31 patietns including a case of successful replacement of his failed xenogragt mitral valve : 4 mechanical valves were used in 3 patients and 33 xenograft valves were used in the remaining 28 patients. The size of the valves were not the major problem at the time of opertion because most of the patients had a dilated heart from disease. There were 3 diaths within 30 days of surgery (9.7% operative mortality rate) and 3 late deaths (9.7% late mortality rate) with an overall mortality rate of 19.4%. Twenty-eight early survivors were followed up for a total of 488 patient-months. Thromboembolic complications occurred in 5 patients with 2 deaths: cmbolic rate of 17.9% or the actuarial embolic incidence of 12.29%/patients-year. four xenograft tissue valves in 4 patients had failed during the period from 19 to 41 months of surgery with an overall valve failure rate of xenograft of 14.3% or the actuarial incidence of 9.84% failure/patient-year. One of these 4 patients had required replacement of his failed mitral xenograft valve which had severe calcification and tissue disruption with primary tissue failure rate of 3.6% or the actuarial incidence of 3.13% failure/patient-year. The actuarial survial including the operative morality was 50.0% at 5 years of surgery. /the actuarial incidence free from thromboembolism in bioprosthetic group was 85.4% at 42 months, while it was 33.4% in mechanicial group at 60 months after operation. The actuarial incidence free from overall valve failur of 100.0% until 18 months after surgery was followed by a rapid decrease during the next 2-year period, and it was only 17.8% at the follow-up end of 42 months after surgery. It was suggested that the major advantage of low thrombogenecity with xenograft valve should be balanced against the high incidence of accelerated valve failure when it is used in children whose age is younger than 15 years old. The possible role of recurrent rheumatic attacks to the early failure of xenograft tissue valve was also discussed.

• Land and Housing Review
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• v.2 no.2
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• pp.101-109
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• 2011

Recently, the construction of U-City or of U-City service (U-service) in many kinds of urban development projects becomes the general trend. However, as the construction of U-city comes into the spotlight like the trend of the times, various service constructions are being indiscreetly implemented since it's processed focusing on local specialized projects or local landmark project by a local autonomous entity or an institute in charge being off the original purpose of the improvement of living quality of residents and the efficiency of urban management, which causes a number of problems on the process, maintenance, operation and management of those projects. Therefore, this study is to derive the standard pattern of U-service construction through the analysis of patterns and numbers of U-service and problems during the process of construction in domestic U-City construction case district, and is aimed to suggest the reasonable direction of service construction based on this. 11 projects areas in which data related to U-service are available among U-City construction project areas were selected for the subjects of this study, and it's standardized with 228 detailed unit services that were suggested by U-Eco City R&D and with 11 service domains that are regulated in "the Act of ubiquitous city construction etc.", and it is limited to services that were suggested in U-City case area of which design was completed by July, 2010 based on this. The actual state of various U-service construction is analyzed through case studies as well as reviews on the legal and theoretical concept and the method of pattern classification of U-service, the plan for the standardization (pattern classification) of U-service and the plan for the construction body of service and to share the costs are suggested as the plan to construct reasonable U-service based on this for the method and the procedure of this study For the method to construct U-service, the plan to classify the pattern of U-service into the basic service and additional service is suggested, and whether it has the publicity, whether urban infrastructure is included, whether utilities are included, the body of realization, the recipients, the urgency, the importance and the spreading, etc. are suggested for the index to determine the pattern of service. The method to get the executor of a project to construct the basic service, the method to get the executor of a project to construct the most basic service among the group classification of service and to get a private entity and a local autonomous entity to perform additional service in the future, and the method to construct the whole service and to distribute the construction costs were suggested, and the first one that determines the body of construction after dividing U-service into the basic service and the additional service was evaluated to be the most reasonable one. And the plan to solve the problem that the excessive construction costs of U-service are shifted onto the executor of a project through benefit principle, balanced distribution principle and consultation and mediation between the interested parties was suggested for the criteria to share the costs.

• Membrane Journal
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• v.30 no.3
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• pp.158-172
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• 2020

In the aspect of saving energy and water, facilitating the separation membrane for the water treatment has been rising recently as one of the possible solutions. However, microbial biofouling effect is the biggest obstacle that hinders reaching higher permeability over a prolonged period of nanofiltration operation. To solve this problem and fully utilize the filtration membranes with enhanced performance, largely two kinds of solutions are studied and the first and the most commonly mentioned type is the one using the silver nanoparticles. Since silver nanoparticles are important to be well tailored on membrane surface, various methods have been applied and suggested. Using silver nanoparticles however also has the drawbacks or possible toxicity risks, raising the need for other types of utilizing non silver particles to functionalize the membrane, such as copper, graphene or zinc oxides, and amine moieties. Each attempt included in either kind has produced some notable results in killing, preventing, or repelling the bacteria while at the same time, left some unsolved points to be evaluated. In this review, the effects of metal nanoparticles and other materials on the antifouling properties of water treatment membranes are summarized.

• Magazine of the Korean Society of Agricultural Engineers
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• v.24 no.1
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• pp.44-52
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• 1982

Recently, estuary reserovoirs have been actively constructed in Korea and also in Japan there are a large number of estuary reservoirs constructed. But most of the estuary reservoirs are located at the downstream of a river where geographical condition is best for the construction of an enclosing dam. And an effective utilization of water from the estuary reservoir seems to be difficult even if estuary reservoirs are considered to be the water resources the most available for their watershed. Studies on estuary reservoirs so far have been mainly concentrated on the physical and engineering problems of the dam construction itself. The purpose of the present study is to review the estuary reservoir planning in connection with the water resources development and to study a basis of the planning. First, the levels of water use in Korea and Japan were compared with those of other countries in the world. And then, some representative reservoirs were selected to study the roles of a reservoir and water-using conditions in the watershed. Based on the study, a survey was given on the relation between a dam construction upstream and an estuary reservoir construction downstream of a river. Finally, a comprehensive examination was made of the bases of estuary reservoir planning. (1) The estuary reservoir planning is deeply related to the plan for water use develo- pment in the watershed. After the upstream water resources were fully developed up to the most, water reso- urces development by an estuary reservoir should be started. (2) If an estuary lake has a capacity big enough, it can store flood discharge of the watershed without any loss and become a basic facility that will bring about the maxi- mum use of water from the watershed. (3) Estuary reservoirs store water used in the upstream watershed, so recycling of water use is attained by the reservoir. Water in the estuary lake is difficult to be fresh water in its long run. Therefore, estuary reservoir should be located at a place where polluted water is purified and refused. All the planning should be based on the assumption that water in the estuary lake is not fresh but polluted after a long time. (4) The estuary lake can only supply water to the lower basin directly. But the upstream area is benefited from the estuary lake by exchange of irrigation water sources between the lower and the upper area. So a large-scale exchange plan between new and existing water resources is important. By constructing estuary reservoirs and the exchange of water sources between upper and lower areas, the reasonable maximum use of water from the whole watershed is at- tained. (5) The big problem coming from the water resources development by an enclosing estuary is salt water intrusion into the lake. To maintain the estuary lake salt-free, multi-purpose use of the lake should be avoided. It is necessary to take such fundamental measures as abolition of back flow operation of gate, and the closing of the fish port and the fish ladder. The results mentioned above were found in this study and these results of this study could be used for the adequate planning of estuary reservoirs in connection with the maximum water use of the watershed.

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.2
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• pp.371-384
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• 2010

This research investigates the historical changes of the educational system for the clothing departments at vocational high schools. According to the growth of the fashion industry, employment potential in the clothing departments of the vocational high schools, numerical changes in the educational statistics, and curriculums were investigated by papers, reports, and statistic data. The statistic data were derived from the 'Center Educational Statistics and Information', 'School Information' (Hak-gyo Alimi), 'Korean Statistical Information Services' and internet home pages of vocational high schools. Technical service workers that graduate from clothing departments and vocational high schools have limited competitiveness in a thriving fashion industry field. Highly developed fashion industries require more professional workers in fashion design, fashion marketing, and fashion materials. Compared to 1994, when 35 classes were conducted in 5 vocational high schools, 69 classes are now conducted at 15 schools. They have over 2,000 students and produce over 600 graduates. However, 222 credits of the $1^{st}$ curriculum in 1958 went down to 82 credits in the 2007 revised curriculum to complete the credits of clothing departments. The 15 courses of the 1st curriculum fell to 5 courses in the 2007 revised curriculum on the number of major subjects. It is a fundamental problem that major courses in clothing education have been excessively reduced despite the demand for of highly specialized workers in the fashion industry. In the view of operating conditions of those schools, there were several problems such as the wide gaps in the curriculum, limited equipment, the supply of teachers, and counseling on the choice of college or a career. In conclusion, the following measures are required: 1) the increase of complement credits in major subjects and renovation of curriculum, 2) national substantial support to change the social circumstance concerning vocational education and occupational consciousness, 3) operation of credit approving systems in universities and colleges for students that have completed the same courses at vocational high schools, 4) designing realistic programs for vocational education and cooperation systems with corporate enterprises.

• Journal of Elementary Mathematics Education in Korea
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• v.10 no.2
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• pp.221-242
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• 2006

For teaching division more effectively, it is necessary to know students' informal knowledge before they learned formal knowledge about division. The purpose of this study is to research students' informal knowledge of division and to analyze meaningful suggestions to link formal knowledge of division in elementary school mathematics. According to this purpose, two research questions were set up as follows: (1) What is the students' informal knowledge before they learned formal knowledge about division in elementary school mathematics? (2) What is the difference of thinking strategies between students who have learned formal knowledge and students who have not learned formal knowledge? The conclusions are as follows: First, informal knowledge of division of natural numbers used by grade 1 and 2 varies from using concrete materials to formal operations. Second, students learning formal knowledge do not use so various strategies because of limited problem solving methods by formal knowledge. Third, acquisition of algorithm is not a prior condition for solving problems. Fourth, it is necessary that formal knowledge is connected to informal knowledge when teaching mathematics. Fifth, it is necessary to teach not only algorithms but also various strategies in the area of number and operation.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.16 no.2
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• pp.113-117
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• 2005

Background and Objective : Vocal fold augmentation by injectable material under direct visual control is an easy and simple operation. However, when autologous fat or bovine collagen is used, the resoiption creates a problem. And autologous fascia is debating about absorption now days. We previously reported on the one year results of injected autologous auricular cartilage for volumetric augmentation in paralyzed canine vocal cord. This study evaluates the long-term histomorphologic results of injected autologous auricular cartilage for the augmentation of the paralyzed canine vocal fold at two year. Material and Methods . A prospective trial of autologous cartilage augmentation of vocal cord in animal model. Three dogs were operated upon. A piece of auricular cartilage was harvested from the ear and minced into tiny chips with a scalpel. Fat was harvested from inguinal area and minced with a scalpel. The minced cartilage and fat-paste (0.2ml) was injected using a pressure syringe into the paralyzed thyroarytenoid muscle using direct laryngoscopy. Three animals were sacrificed at 2 years. Each subject underwent laryngectomy and serial coronal sections of paraffin blocks from the posterior vocal fold were made. Results There was no significant complication perioperatively and during follow-up. The injected cartilage which appeared to have lost viability existed in the vocalis muscles until 24 months. Fibrotic change was exhibited in the surrounding injected cartilage. Conclusion : The autologous auricular cartilage graft is well tolerated and may be very effective material for volumetric augmentation on paralyzed vocal cord.