• Explosives and Blasting
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• v.9 no.4
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• pp.13-21
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• 1991

This study is concerned with the disasters that occure in the field of industrial explosives and analyzed by two side the disaster of the manufacturing factory and that of the field, and is studied about the safety and the countermeasure. The industrial explosives accidents occure just accidentaly and unforeseeable, and reappearance experiments are more difficult. The 3E of J.H. Harvey was applied in this study to establish the counter measure of preventation of accidents, overcoming these restricted factores. As a method of technical safety countermeasures. The blasting vibration formula which had been conformed from the Seoul Subway Construction work during 1980-1984 year, was uilized, and, using the formula $V=Kw^{0.5}D^{-1.5}$ for the gneiss which is widely distributed in Pusan area, an index of the minimum and maximum amount of gun powder, to be used according to safety distance was made, and it helped the gun powder managing technician's practical business. During the fore work discharging, the safety distances of felling were theoretically established based on the writer ${\diagdown}s$ experiences of more than 10 years on this field.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.725-726
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• 2006

In large scale superconducting rotating machine, HTS field coils are constructed with many stacks of single or double pancake coils connected in series. In spite of its higher thermal stability, HTS field coil experiences some quench, which results in some part of burn-out in the field coils. Thus in the view point of the HTS rotating machine field coil design and testing, it was very important to predict the possibility of quench occurrence in the designed field coils. In this paper, a HTS racetrack coil constructed with two single pancake coils and one double pancake coil was tested in LN2 and cooling by GM refrigerator. It is wound using the Bi-2223 tape. The experimental details and results are presented in this paper.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.711-722
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• 2008

A projectile when passes through a moving shock wave, experiences drastic changes in the aerodynamic forces as it moves from a high-pressure region to a low pressure region. These sudden changes in the forces are attributed to the wave structures produced by the projectile-flow field interaction, and are responsible for destabilizing the trajectory of the projectile. These flow fields are usually encountered in the vicinity of the launch tube exit of a ballistic range facility, thrusters, retro-rocket firings, silo injections, missile firing ballistics, etc. In earlier works, projectile was assumed in a steady flow field when the computations start and the blast wave maintains a constant strength. However, in real situations, the projectile produces transient effects in the flow field which have a deterministic effect on the overtaking process. In the present work, the overtaking problem encountered in the near-field of muzzle guns is investigated for several projectile Mach numbers. Computations have been carried out using a chimera mesh scheme. The results show that, the unsteady wave structures are completely different from that of the steady flow field where the blast wave maintains a constant strength, and the supersonic and subsonic overtaking conditions cannot be distinguished by identifying the projectile bow shock wave only.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.47.1-47.1
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• 2018

Solar cycles are inherent to the Sun, which experiences temporal changes in its magnetic activity via the surface distribution of the solar magnetic field. This raises a fundamental question of how to derive the distribution characteristics of a solar-surface magnetic field that are responsible for individual solar cycles. We present a new approach to deriving as long-term and large-scale distribution characteristics of this quantity as was ever obtained; that is, we conducted a population ecological analysis of Wilcox Solar Observatory (WSO) Synoptic Charts which provide a more than 40-year time series of latitude-longitude maps of solar-surface magnetic fields. In this approach, solar-surface magnetic fields are assumed as hypothetical trees with magnetic polarities (magnetic trees) distributed on the Sun. Accordingly, we identified a peculiarity of cycle 23 with a longer period than an average period of 11 years; specifically we found that the negative surface magnetic field had much more clumped distributions than the positive surface magnetic field during the first one-third of this cycle, while the latter was dominant over the former. The Sun eventually spent more than one-third of cycle 23 recovering from these imbalances.

• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.740-753
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• 2013

The purpose of this study was to examine present condition of social work field education, students' stress/stress coping strategies in their field practicum, and to find out the difference according to the factors related field education. This study carried out a survey targeting 202 students who finished their social work field practicum and took their course work in 2012, from 4 different universities in the northern Gyeonggi province & Seoul. As the result, in the area of stress, the highest rank was the lack of professional knowledge/skills, the second was the environment of field practicum, and the third was the burden of tasks that they had to perform. About the coping strategies, it was found that students utilized 'problem-solving focused' the most, pursuing 'social support' as the second, and 'avoidance' strategies as the least. Factors influencing on differences of stress level depending on field work experiences were whether they had previous field experience, how much time they participated in previous volunteer activities, whether they attended orientation for their field practicum, regularity/frequency of supervision, the satisfaction on their social work/welfare major, and the satisfaction on their field practicum or supervision. Based on the results, suggestions for development in field education system were presented.

• Proceedings of the Korean Geotechical Society Conference
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• 1993.10a
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• pp.43-50
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• 1993

It has been past for many years that soil-cement used in the field of roadway pavement in America and Europe. Though the design and construction criteria on soil-cement pavement have been well setablished in Korea's specificaions, this method has not been applied in roadway pavements, in practices. It is mainly caused by the lacks of experiences in soil-cement pavement design and construction. In this study, the problems of soil-cement pavement in use were explored, and the structure and fatigue like of soil-cement bases and subbases were estimated.

• The Journal of Korean Medical History
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• v.13 no.1
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• pp.73-102
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• 2000

This book is unique in that acupuncturist Hur Im, who practiced in the mid-chosen era, had written about clinical experiences throughout the author's life. It features simplicity and practicality. The book has had tremendous effect in the field of acupuncture at the end of chosen era and it was also published both in China and in Japan with much appraisal.

• Journal of the Korean Professional Engineers Association
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• v.42 no.3
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• pp.32-34
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• 2009

The number of Construction Management Professional(CMP) is 2700 among 4600 of the total CMPs in Korea. Their characters and abilities are quite different from others. Because they must have 10 year field experiences, complete 180 hours CM oriented lectures and pass the certification test including written and interview in depth. And then, their level of standard is maintained by the Continuous Professional Development(CPD) program, periodic forum, case study seminar and CMP vision execution strategy sponsored by the CMP Association.

• Progress in Superconductivity and Cryogenics
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• v.19 no.4
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• pp.1-11
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• 2017

This article reviews the recent activities of field testing and application of superconducting fault current limiters (SFCL) based on high-temperature superconductors (HTS). The review particularly focuses on the trends in the field tests in terms of the technical aspects and commercial activities of the SFCLs. Stimulated by the discovery of HTS, numerous research and development activities have been conducted worldwide for SFCLs operating from distribution voltages to transmission voltages. Different types of SFCLs have been developed and field-tested. Consequently, more than 20 field tests and applications have been performed on real grids worldwide while supplying electric power to the customers. These field tests have not only provided the track records of the operation experiences including the problems and maintenance during operation, but also proved their current limiting capabilities against real faults, rendering this new technology highly viable. Through these activities, the following trends in the status of field testing and application are observed. Resistive-type SFCLs with HTS-coated conductors were dominantly used in the most recent field tests. This implies that the resistive type is technically more mature than the other types. Bus-bar coupling and transformer feeders were the major application locations. It is of importance that most of the field applications were conducted as R&D projects. A relevant change from the R&D stage to the application stage is shown as recently deployed SFCLs are expected to be under long-term operation and commercial service. Here, we review the installation of these SFCLs by substation. This review also discusses the recent activities for their commercial applications.

• Korean Journal of Computational Design and Engineering
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• v.15 no.6
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• pp.460-466
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• 2010

These days, it is getting important to have more chances to visit natural environment for the wellbeing life. The advancement of digital technologies allows us to get useful information regardless of time and location. In this paper, we investigate a way of improving user experience in the natural green environment using the digital technologies. This paper proposes a system called Green-UX-Story which supports users to create and share their story through the online and offline green experience. The system consists of two main systems: the "Story-Field" and the "Story-Tree". The Story-Field consists of a certain number of the Story-Trees allocated to a certain green site. In the Story-Field, users can see the Story-Trees that are owned by other users and share their stories. The Story-Tree contains the user-story in each branch and green information that are captured by the user on the web. The Story-Tree is generated using the L-system algorithm as the user adds stories. The main purpose of the system is to enable users to write their green stories from the both online and offline experiences. This paper describes the system configuration and the user scenario of the Green-UX-story.