• International Journal of Fluid Machinery and Systems
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• v.2 no.2
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• pp.110-120
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• 2009

Generally the fluid flows within the centrifugal impeller passage as a decelerating flow with an adverse pressure gradient along the stream wise path. This flow tends to be in a state of instability with flow separation zones on the suction surface and on the front shroud. Hence several experimental attempts were earlier made to assess the efficacy of using boundary layer fences to trip the flow in the regions of separation and to make the flow align itself into stream wise direction so that the losses could be minimized and overall efficiency of the diffusion process in the fan could be increased. With the development of CFD, an extensive numerical whole field analysis of the effect of boundary layer fences in discrete regions of suspected separation points is possible. But it is found from the literature that there have been no significant attempts to use this tool to explore numerically the utility of the fences on the flow field. This paper attempts to explore the effect of boundary layer fences corresponding to various geometrical configurations on the impeller as well as on the diffuser. It is shown from the analysis that the fences located on the impellers near the trailing edge on pressure side and suction side improves the static pressure recovery across the fan. Fences provided at the radial mid-span on the pressure side of the diffuser vane and near the leading edge and trailing edge of the suction side of diffuser vanes also improve the static pressure recovery across the fan.

• Journal of the Korean Geographical Society
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• v.51 no.6
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• pp.739-759
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• 2016

C. Gottsche(1855-1909), the Deutsch geologist, was invited by $M{\ddot{o}}llendorff$ who was the viceminister of foreign affairs in Korea, and travelled through the inland of Korean peninsula in 1884. He covered 2,550km in 138 days. After that journey, he wrote three academic papers about the geography and geology of Korea with the data of that field trip. Those paper bear considerable significance in that they included the first approaches to Korean geography and geology by a field-scientist with a modern academic training. Unlike other two papers focusing on the geology or the minerals, "The Geography of Korea(${\ddot{U}}ber$ Land und Leute in Korea(1886))" has its own value as a historical document, because it shows how the contempory Korea actually appeared to the eye of a $19^{th}$ western field-scientist. As this has not been introduced in Korean acdemic journals yet, this study might contribute to the understanding of how westerners regarded Korea in the end of 19th century.

• Korean Journal of Human Ecology
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• v.18 no.1
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• pp.113-122
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• 2009

This study aimed to examine the urban families and rural families in tenns of life styles on Saturday-with-no-school. The subjects were the 386 parents whose children were in the first or second grade in rural or urban area. The instruments of analysis were time diary method and parents' stress scale developed by Kim & Kang(l997). The main results were as follows: First, in comparison with urban children, rural children spent more time in viewing TV and playing computer but spend less time in sleeping. field trip and cleaning on Saturday-with-no-school. Second, the difference of child-rearing time between mothers and fathers was less marked in urban area than in rural area. Rural fathers spent more time in watching TV or playing computer, while rural mothers spent more time in feeding and bathing of their children, helping their children do homework, and total child-rearing. Third, unlike urban parents, rural parents ddid not have much parenting stress on Saturday-with-no-school. These results show that there is a need to focus on rural parents in the preparation for introduction of 5 days-school-week system.

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.31.3-31.3
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• 2008

Satellite laser ranging (SLR) system which measures the round trip time of laser to satellites is one of the important techniques in space geodesy. SLR system gives a powerful tool to determine the precise orbit of satellites, the center of mass of the Earth, and etc because it provides instantaneous range measurements of millimeter level precision. China Transportable Ranging Observation System (TROS) was built in 1999 and other four SLR stations were founded in China. TROS has been upgraded to the new electronic system capable of KHz ranging since last year, and succeeded in KHz SLR technology. TROS has been operated in KASI headquarter for research of space geodesy since August 2008, which will be operated for 12 months by August 2009. Now ISCEA and KASI keep strong relationship in SLR field.

• Journal of The Korean Association For Science Education
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• v.21 no.5
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• pp.867-892
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• 2001

In both Korea and the U.S., science education leaders and specialists insist that there is a shortage of curricula to address the new national science education guidelines in support of reform. This paper addresses development of new curricula for science education reform in the hopes of facilitating further development of guideline-based curricula. We examine Korean and U.S. thematic-based (Korean Science Field Trip at Cultural Sites Program and U.S. Graduate Teaching Fellows in K-12 Education) and project-centered (Korean Teachers for Exciting Science and U.S. Foundational Approaches in Science Teaching Program) programs. Using the criteria of rationale for curriculum, content and scope, processes of implementation, and assessment strategies, we identify the curricular components that are common across four successful secondary science programs and determine which of these components address the national guidelines. Our findings indicate that common components of these four programs meet the expectations of the science guidelines being used to revamp science education in both countries. Therefore, these programs not only engage secondary students and teachers in practicing successful science education, but also lead to successful science education practices that can be incorporated in the future development of curriculum to support secondary science reform.

• Fire Science and Engineering
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• v.20 no.3 s.63
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• pp.48-53
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• 2006

The aim of the study intends to investigate the fire safety awareness level of the young children's parents in Seoul and to provide the base data in the education for the fire safety. The results of the study are as follows. The young children's parents consider the fire safety awareness level of our society low, though their fire safety awareness level be above the average. The young children's parents choose infants schools as appropriate place to receive education for fire safety. And the young children's parents consider the development and diffusion of fire-safety teaching materials for young children to be supplied first of all. Also the young children's parents recognized observation learning and a field trip activity as appropriate teaching-learning method for fire-safety education.

• Journal of Families and Better Life
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• v.20 no.4
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• pp.53-60
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• 2002

The purpose of this study was to comprehend the cognition of Korean tradition and the required basic educational contents among interior architects. The survey had been made 277 designers and the major findings of this study are as follows. First. It is revealed that only a half of interior architect have been taught about Korean tradition in university and their level of knowledge is entry level. Therefore it is found that the education in university on the Korean tradition was not sufficient enough Second, it is believed that one ideal way of expressing Korean tradition is re-interpreting traditional motive with modern views and another way is to express abstractly about Korean traditional space arrangement, composition and space concept. It is found that substantial knowledge and information is required to express Korean tradition effectively. Third. it is found that a lot of interior architect has faced difficulties in carrying out projects because of not having sufficient knowledge related to Korean tradition. Therefore it is recommended to educate basic theory about Korean tradition first and then reinforce the program by including field trip In university curriculum. Fourth. it is necessary to re-educate to current Interior architect because of lacking knowledge about Korean tradition. The recommended area in priority order is traditional Interior space, traditional architecture, traditional color, traditional pattern and traditional furniture

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.7
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• pp.67-74
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• 2009

This paper describes the speed control functions of the typical steam turbine speed controllers and the test results of generator load rejection simulations. The goal of the test is to verify the speed controller's ability to limit the steam turbine's peak speed within a predetermined level in the event of generator load loss. During normal operations, the balance between the driving force of the steam turbine and the braking force of the generator load is maintained and the speed of the turbine-generator is constant. Upon the generator's load loss, in other word, the load rejection, the turbine speed would rapidly increase up to the peak speed at a fast acceleration rate. It is required that the speed controller has the ability to limit the peak speed below the overspeed trip point, which is typically 110[%] of rated speed. If an actual load rejection occurs, a substantial amount of stresses will be applied to the turbine as well as other equipments, In order to avoid this unwanted situation, not an actual test but the other method is necessary. We are currently developing the turbine control system for another nuclear power plant and have plan to do the simulation suggested in this paper.

• Journal of Electrochemical Science and Technology
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• v.6 no.2
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• pp.50-58
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• 2015

There is a great deal of current interest in the development of rechargeable batteries with high energy storage capability due to an increasing demand for electric vehicles (EVs) with driving ranges comparable to those of gasoline-powered vehicles. Among various types of batteries under development, a Li-O₂ battery delivers the highest theoretical energy density; thus, it is considered a promising energy storage technology for EV applications. Despite the fact that extensive research efforts have been made in the field of Li-O₂ batteries in recent years, there are still many technical challenges to be addressed, such as low round-trip efficiency, poor reversibility, and poor power capability. In this article, we provide a short review on the fundamental electrochemistry of Li-O₂ batteries with non-aqueous electrolytes and on electrode materials that have been employed in cathodes (oxygen electrodes). The major aim of this mini-review is to highlight the physical and electrochemical origins of scientific challenges facing Li-O₂ battery technology and to overview the strategies proposed to overcome them.

• Journal of Korean Society on Water Environment
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• v.25 no.6
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• pp.964-971
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• 2009

In this paper, activated sludge settling was characterized based on field trip and zone settling tests. Plants used for this study include 5 conventional activated sludge processes and 3 A2O type treatment processes. The treatment capacities are in the range from 12,000 to $250,000m^3$/day. Total number of zone settling tests were 188 set and SVI values representing settling characteristics were from 100 to 300 mL/g. It was found out that zone settling velocity of these examined plant sludges can be approximated by mean values calculated by Keinath and Daigger/Roper models. Based on these three models, solid flux analysis were carried out in order to compare design criteria ($3.96{\sim}6.04kg/m^2-hr$) recommended by Korea Sewage Facility Design Guideline with two models used in USA. The results show that design criteria are only applicable for normal condition in settling characteristics (below SVI 100 mL/g). Solid flux analysis of surveyed plants indicates that most of the plants are operated underload conditions except several plants experiencing poor sludge settling problem. Most of the plants are operated under high sludge blanket depths (SBD).