• Journal of Korean Elementary Science Education
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• v.20 no.1
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• pp.59-73
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• 2001

The National Science Fairs has been held in every year for the promotion of science and technology and scientific civil life. The purpose of this study is to survey the current problems in National Science Fairs by making up a question and to improve them. The study makes up a questionnaires about the existing Science Fairs to the teachers who have submitted their works to the Science Fairs and suggest the ways of improvement. The result of questionnaires is that little availability of reference materials, difficulty of paying proper attention to regular classes because of frequent travels, and absence of experimental devices and experimental rooms are perceived as major obstacles in preparing for the exhibition. Respondents teacher also pointed out some problems with the current organization of the exhibition; non-voluntary selection process for the potential authors, separation of research content from regular teaching materials, unrealistically high standard, low participation rate of teachers, so many exhibited works, lack of professionalism in the screening process. The majority however, agreed that the exhibition event should be continuously done, after remedial measures have been taken about the problems. First, the side of science education is emphasized in a purpose of the science fairs to let activity related to science fair be closely connected with school education. Second, students have to be divided according to grade. Third, research level have to be set not too higher than regular instruction content. Fourth, hand book related to science fairs have to be manufactured and spread. Fifth, data of local science fair have to be arranged. Sixth, judging section have to be subdivided and people related to science education have to be included to a judge. Seventh, excellent works have to be support to participate in ISEF.

• Nuclear Engineering and Technology
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• v.46 no.5
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• pp.581-594
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• 2014

A feasibility study on the seismic design of nuclear reactor buildings with application of a seismic isolation system is introduced. After the Hyogo-ken Nanbu earthquake in Japan of 1995, seismic isolation technologies have been widely employed for commercial buildings. Having become a mature technology, seismic isolation systems can be applied to NPP facilities in areas of high seismicity. Two reactor buildings are discussed, representing the PWR and BWR buildings in Japan, and the application of seismic isolation systems is discussed. The isolation system employing rubber bearings with a lead plug positioned (LRB) is examined. Through a series of seismic response analyses using the so-named standard design earthquake motions covering the design basis earthquake motions obtained for NPP sites in Japan, the responses of the seismic isolated reactor buildings are evaluated. It is revealed that for the building structures examined herein: (1) the responses of both isolated buildings and isolating LRBs fulfill the specified design criteria; (2) the responses obtained for the isolating LRBs first reach the ultimate condition when intensity of motion is 2.0 to 2.5 times as large as that of the design-basis; and (3) the responses of isolated reactor building fall below the range of the prescribed criteria.

• Korean Journal of Materials Research
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• v.24 no.2
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• pp.87-92
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• 2014

The Notched Ring Test(NRT) has proven to be very useful in determining the slow crack growth behavior of polyethylene pressure pipes. In particular, the test is simple and an order of magnitude shorter in experimental times as compared to the currently used Notched Pipe Test(NPT), which makes this method attractive for use as the accelerated slow crack growth test. In addition, since the NRT specimen is taken directly from the pipe, having maintained the cross-section, processing induced artifacts that would affect the slow crack growth behavior are not altered. This makes the direct comparison to the slow crack growth specimen in pipe from more meaningful. In this study, for comparison with other available slow crack growth methods, including the NPT, the stress intensity factor equation for NRT specimen was developed and demonstrated of its accuracy within 3% of that obtained from the finite element analysis. The equation was derived using a flexure formula of curved beam bending along with numerically determined geometric factors. The accuracy of the equation was successfully tested on 63, 110, 140, 160, 250, and 400 mm nominal pipe diameters, with crack depth ranging from 15 % to 45 % of the pipe wall thickness, and for standard dimensional ratio(SDR) of 9, 11, and 13.6. Using this equation the slow crack results from 110SDR11 NRT specimen were compared to that from the NPT specimen, which demonstrated that the NRT specimen was equivalent to the NPT specimen in creating the slow crack, however in much shorter experimental times.

• The Journal of Pediatrics of Korean Medicine
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• v.19 no.2
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• pp.115-126
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• 2005

Objective : The aim of this study is to investigate rota virus infection of neonates In the Postpartum care center. Methods : This clinical study was carried out with the 205 neonates who admitted to the Postpartum Care Center of ${\bigcirc}{\bigcirc}$ Oriental Medicine Hospital, from July, 2004 to July, 2005. Stools were examined daily with Rotazyme ELISA tests(Bio Line Rota Virus, SD Standard Diagnostics, INC.) for 3 days from the day of admission. Supplementary test was examined when change was found in stools. Results : Among 205 newborn babies, 58 cases turned out to be positive. The positive rate of rota virus was not significantly related to sex, birth weight, gestation age. But, it was significantly related to delivery method and it was higher in caesarean section group. The manifestation rates of symptoms were 51.7% in Rotazyme positive neonates. In the Rotazyme positive 58 cases, 30 cases(51.7%) had diarrhea, 8 cases had fever(13.8%), 1 case(1.7%) had vomiting. The positive rate of rota virus was higher during from october to march. There were 190 cases(92.2%) of mixed feeding and 15 cases(7.8%) of artificial feeding. There was significance between breast feeding and the positive rate of rota virus. There was no significance between hospital of birth and the rate of positive rotazyme test. Conclusions : A further study of neonates in postpartum care center is necessary as preference of postpartum care center was increased. And the oriental medicine treatment of rota virus IS expected to be effective, so a further study is necessary.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.4
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• pp.925-935
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• 2016

It is provided that seafarers qualified in accordance with STCW(International Convention on Standards of Training Certification and Watch-keeping for Seafarers) convention and code in safety training shall be required, every five years, to provide evidence of having maintained the required standard of competence, to undertake the tasks, duties and responsibilities listed in Chapter VI, section A-VI/1 of the STCW Code A. Every party to the STCW Convention has amended the relevant national regulations according to the above international convention and code. These amended Seaman's Act require the updating safety training which is only five years valid for existing seafarers serving onboard ship on international voyage. And above specified existing seafarers must, as of the 1st January 2017, have documentary evidence of either having completed the training course or updated their training within the last 5 years. In relation to the above international trend, the Korean Ministry of Oceans and Fisheries also has completed an amendment to its Seaman's Act. But, the Korean Seaman's Act has a supplementary provision to exempt the seafarers who have completed STCW advanced safety training from basic safety training. The purpose of this study is to define the problems of above mentioned exemption provisions and to make better policies for improvement. In order to complete the purpose, the research team has conducted an in-depth survey of various foreign cases on STCW safety training. Moreover, the team has suggested an improvement scheme in consonance with Korean shipping industry and society through out this report.

• Journal of the Korean Society for Railway
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• v.13 no.6
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• pp.565-569
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• 2010

Sleepers perform bearing rails and are underneath rails. Therefore, the current and voltage of rails are related to the resistance of sleepers. In case that the resistance of sleepers are low, operation problems of relays in tr ack circuits are occur because of flowing leakage current through sleepers. So the condition that the track circuit is always occupied by a train is kept. Currently, the creosote has been used in wood sleepers due to prevention against putrefaction. After a long time, the material is changeable to the chemistry material bases on carbon dioxide or carbon. So, the insulation resistance of wood sleepers is lower than the initial insulation resistance. In case of effecting wood sleepers as conductors, amplitude of the current and voltage on rails is decreased. This phenomenon causes that a train does not receive signals. In this paper, four-network model on the track circuit including the insulation resistance of sleepers is suggested. Also, the standard value of the resistance in straight section is proposed in the wood sleeper.

• Journal of architectural history
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• v.21 no.5
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• pp.19-32
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• 2012

The purpose of this paper is a study on the dome plan of S. M. del Fiore Church of F. Brunelleschi. The results of study are as follows: 1. The planning of floor, elevation and cross section plan of S. M. del Fiore church is basically planned by each other correlation. In particular, the octangular form of geometrical standard which is formed with altar as the center at the crossing part is important component elements which is decided by not only the dome, but form and size of the drum and floor plan form of the lantern 2. The dome which has been planned by F. Brunelleshi has completed the new dome, preserving gothic thought intended by the church plan after study on architecture of ancient Rome with Pantheon. And the dome which is a main space of church through all aspects of plan, structure, function and construction about the dome is a opportunity in the beginning of Renaissance architecture which is a new epoch and a turning point of architecture on various point of view. 3. The dome which is constructed by F. Brunelleshi has been planned through the innovative solution by the refusal of traditional semicircle form dome, centering use and creation double-shell structure form for the first time in history. And the construction of dome has been solved with the invention of various construction equipments and machineries, the stone rib planned for connection and reinforcement about shells of the octangular form, the support method for reduction the gravity of bricklayers work and the brick work of nock-patterned shape which is masonry construction method of the architecture of ancient Rome.

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.2
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• pp.39-45
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• 2006

In liquid rocket engine turbopump, it is difficult to evaluate turbine performance for high pressure, high temperature circumstance. Turbine test is often done by using air at similarity condition so that the turbine can be tested at lower risk. This paper describes an air similarity test program of liquid rocket engine turbopump turbine. A test facility has been built to evaluate aerodynamic performance of turbines. The test facility consists of high pressure air supply system, mass flow rate measuring nozzle, test section, hydraulic break, exit orifice for pressure control, instrumentation and control system. This paper also presents how to decide the similarity conditions of the turbine test and describes how to control test conditions. Relative standard deviation of measurement parameter was less than 1% and measured turbine efficiency corresponded with analysis result within 2%.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.213-216
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• 2008

When using the light-weight form with polystyrene on slab, as a result of reducing the weight of slab, the span was increased or size of supporting member for slab was decreased. But capacity of punching shear resistance on the slab using the polystyrene form with plat plate system was deteriorated at critical section around the column. But standard for estimate of internal force did not exist, and established study was insufficient. This study performed the experiment on the punching shear for understanding punching shear force at the slab-column connection using the slab with polystyrene form. The principal variable was size of column, arrangement of polystyrene form and existence of shear reinforcement, and we planned four specimens. From the test, we analysed the crack, failure mode, road-displacement graph and punching shear strength, and capacity of punching shear resistance for slab using the polystyrene form was understood.

• Journal of the Korean GEO-environmental Society
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• v.17 no.8
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• pp.5-15
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• 2016

As the increase of domestic sewage treatment plant and reinforcement of the standard of effluent water quality continues, the volumes of sewage sludge are consistently increasing. Existing treatment of sewage sludge, such as incineration and ocean dumping has been prohibited because of air pollution and prohibitions towards ocean dumping, and in turn, recycling and energy recovery from waste methods have being studied recently. However, the lack of technical level and systematic analyses of application technique are problems, that future analysis of such relative technique would be required. The present study has been investigated as follows, management technique of sludge, patent on refuse-derived fuel and increase biogas production and utilizable technology, trend of research paper. Furthermore, research development from five developed nations (Korea, Japan, China, United States, and United Kingdom), domestic and foreign have been investigated and analyzed by section. In this study, the future technical field which is required for effective management of sludge has been suggested.