• Journal of the Korean association of regional geographers
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• v.13 no.5
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• pp.526-542
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• 2007

This study look into the place-name change by social influence around Jin-An region. The place-names were made through joining natural environment with social condition. The place-names were born as a river name firstly, and it was selected as the artificial administration district name in this region(Ju-Chon, Jeong-Chon, An-Chon). Generally the place-name is reflected by a terrain feature of narrow area but this region's place name was made by wide river drainage area as a system. It is different point to others place-name and the social factor played more important role than natural environment in this process. The displacement process of mountain name which is from Ju-Jul to Un-Jang was through social situation change without the natural conditions change. It was used to the Ju-Jul firstly and coexistent the Ju-Jul with Un-Jang and only use the Un-Jang recently. Formal change period was 1910s in the map, Mt. Un-Jang(雲長山) had the advantage at the pronunciation and written than Mt. Ju-Jul. Mt. Gu-Bong(九峰山) was played important role for new mountain name and Song Ik-Pil(宋翼弼) was appeared for rationalization of Mt. Un-Jang.

• Applied Chemistry for Engineering
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• v.18 no.5
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• pp.495-500
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• 2007

The inside wall of a coal gasifier is lined with refractory, and the corrosion of the refractory is an important factor affecting the refractory lifetime and the replacement period. This paper examines the changes in microstructure of a chromia refractory due to chemical reactions with slag having varying amounts of $Fe_2O_3$. Slag samples were prepared by adding $Fe_2O_3$ to KIDECO slag, and static corrosion experiments were carried out at $1550^{\circ}C$. The layer of $(Fe,Cr)_3O_4$ formation and the depth of Fe depletion in the infiltrating slag were determined. In addition, FactSage equilibrium calculations were carried out in order to determine the conditions of formation, and to compare with the experimental observations. In the sample exposed to KIDECO slag, which has about 10 wt% $Fe_2O_3$, the formation of $(Fe,Cr)_3O_4$ was not observed. As the $Fe_2O_3$ concentration in slag increased, $(Fe,Cr)_3O_4$ formation and Fe depletion depth increased. Increasing $Fe_2O_3$ concentration also made the slag/refractory interface indistinguishable. Equilibrium calculations predicted that higher $Fe_2O_3$ concentrations favor chromite formation at gasification temperatures. The chromite formation was most favorable when the amount of $Cr_2O_3$ was limited, as in the case of dissolved $Cr_2O_3$ in slag. When the concentration of $Fe_2O_3$ in slag was less than 20%, the formation of chromite was least favorable in the system with equal amounts of slag and refractory.

• Journal of dental hygiene science
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• v.16 no.1
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• pp.93-100
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• 2016

The purpose of this study was to compare the changes of retentive force in different stud attachment systems for implant retained overdenture. Two commercially available attachments with different retentive forces were investigated: Kerator (pink, blue, red) and O-ring (orange, red). Two implant fixtures were vertically embedded in base mountings. Five pairs of each attachment were evaluated. A universal testing machine was used to evaluate the retentive force of two attachments during wear simulation. Surface characteristics of each attachment system were evaluated with scanning electron microscopy. Five pairs of each attachment were evaluated. Kerator pink showed the highest initial retention. After 2,500 cycles of wear-simulation, Kerator pink noted the largest decrease in retention. According to results of surface analysis, Worn surfaces were obtained in matrices and patrices. Heavy wears were observed in matrices. After 2 year-wear simulation, most attachments exhibited retention loss. Attachments using different kind of material exhibited dissimilar surface alterations.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.2
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• pp.149-155
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• 2023

Photovoltaic power generation is the most familiar power generation facility among new and renewable energies, and its supply began to expand about 10 years ago, and at this point, interest in solutions and technologies for system maintenance management is increasing. In particular, it is necessary to take measures to maximize the overall efficiency of the solar power generation system, whether or not there is an abnormality in the solar power generation system, and when to replace parts. The PV inverter, one element of the photovoltaic power generation system, is a power conversion system that relies on power switching devices, and DC-Link capacitors are used according to the configuration of DC/DC converters and DC-AC inverters. These DC capacitors also affect system safety (Safety) through renewable energy facilities due to the decrease in power generation of PV inverters, power loss, and increase in harmonics (THD, total distortion of AC output current) due to aging and deterioration due to long-term use. factors can be analyzed. Therefore, in this paper, the PV inverter operating characteristics according to the DC capacitor capacity state currently operating in the photovoltaic power generation system were considered, and research contents were proposed to secure the safety and reliability of renewable energy facilities.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.205-209
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• 2015

The economic losses resulted from the accident in the power cables at the power station is not only huge but also requires a great amount of time and expenses to restore to the former condition. In order to prevent these, it is necessary to invent and apply a technique to expect and prevent the accidents. In order to measure insulation resistances of power cables in operation, we derived the relations between load current and temperature. By analyzing data obtained from our measuring equipments, we showed the expected time to change deteriorated cables before accident occurs. We present a result of our study on the effects of the load current on lifetime of 6.6 kV cable systems in operation. With the current flowing through the load of the cable a heat is generated reducing the lifetime of the cable. In order to find out the effect of load current on the lifetime of cable systems, we applied the lifetime theory to the development of two equipments to measure insulation resistance and current of cable systems in operation.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2001.11a
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• pp.174-175
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• 2001

미나리 묘를 대량으로 생산하는데 있어서 체세포배를 이용하는 방법이 매우 유리하다. 체세포배는 계절에 영향을 받지 않고 좁은 공간에서 한꺼번에 많은 량의 묘를 생산할 수 있다. 또한 생물반응기 등을 이용하여 대량 생산할 수 있으면 실생묘를 대체할 수 있을 것으로 생각된다. 배양기 내의 공기 환경의 영향은 삼각플라스크를 이용한 소규모 배양에서는 문제가 되지 않았지만 배양기가 커짐에 따라 공기 환경의 변화도 커져 체세포배의 발생과 발아에 영향을 미친다. 체세포배를 배양하는 기간은 배발생과 발아로 나누어, 세포에서 배가 발생하는 처음 2주 동안에는 밀폐 환경, 즉 환기가 거의 되지 않는 환경이 유리하지만 이후의 발아 동안에는 산소를 많이 요구한다. 삼각플라스크를 이용한 소규모 배양에서는 aluminum foil을 플라스크의 뚜껑으로 하여, 배지를 교체할 때를 제외하고는 배발생과 발아가 진행되는 전 배양 기간 동안 이를 유지한다. 배가 발생하는 초기 2주의 경우는 이 밀폐 환경이 발아를 촉진시킨다. 그러나 배가 발아하여 정상 식물체로 발달하는데는 유리하지 않다. 체세포배는 발아할 때 산소를 많이 필요로 하며 에틸렌이 많이 축적되면 발아율이 낮아지며, 적절한 공기 환경이 주어지면 체세포배 발아가 동조화되어 균일한 묘를 얻을 수 있고 수확시기도 예측할 수 있다. 본 실험에서는 배가 발아하는 기간 동안 플라스크 내의 공기 환경을 다르게 하기 위해 플라스크를 막는 뚜껑의 소재를 달리하여 배양한 후 발아율을 측정하였다. 또한 가장 효율적인 환기량을 구명하기 위하여 인위적으로 플라스크에 공기를 넣어 강제 환기시키는 실험을 수행하였다. 미나리 cell은 처음 8일까지는 생장을 하지 않다가 이후 급속히 생장을 시작하여 35일 정도까지는 생장을 하다가 다시 생장이 둔화되었다. 밀폐시킨 삼각플라스크에서 자라는 Cell은 상태도 좋지 않고 전반적인 증식량도 적었다. Cell은 환기정도에 민감한 것으로 판단되며 삼각플라스크에서 약 35일 정도의 생장 주기를 가지는 것으로 사료된다. 배양 3주까지는 플라스틱 뚜껑으로 밀폐시킨 bottle에서 가장 많은 체세포배를 얻었다. Air filter를 달아 2일 마다 신선한 공기를 넣어 주었을 때는 배의 발달이 많이 늦어져 배양 3주째에 다른 처리보다 배의 수가 훨씬 적었다. 체세포배가 발달하는 동안에는 산소를 많이 요구하지 않으나 성숙하는 동안에는 산소를 많이 요구하는 것으로 생각된다.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.184-184
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• 2011

선로의 레일은 재료적인 특성과 현장의 많은 주변 요소에 의한 불확실성이 매우 높은 시스템으로 결함의 위험이 상존한다. 결함 발생과 조치에 따라 영업손실로 이어지므로 레일 결함 발생과 동시에 적절한 조치가 요구된다. 따라서 레일결함 발생 시 레일교환시기를 파악하는 것이 선로관리비용을 줄일 수 있으며 레일교환에 대한 신속한 판단을 위함 관리기준을 정립하는 것이 요구된다. 현재 국내에서 고속선의 경우 관리 기준이 있으나, 일반철도는 없는 실정이다. 본 연구는 차후 일반철도 180km/h 속도상승을 계획하고 있는 현 시점에 국외 관리기준을 분석하여 결함관리기준을 정립에 기여하고자 한다. 국내의 경우, 2004. 4. 1 프랑스 기술을 전수받아 개통한 고속선은 프랑스 레일관리기준을 적용한 "레일손상 등급별 관리기준"을 제정하여 레일관리를 시행하고 있다. 국외의 경우, INNOTRACK프로젝트 안에서 관련된 다른 IM(Infrastructure Managers, 사회기반시설 관리자들)에게 최근의 활동과 변화의 이해를 제공하기 위해서, 선택된 결함들의 최소조치들의 조사가 Network Rail, OBB, Prorail, Banverket 그리고 DB에서 수행되고 있으며 UIC 지침에도 포함되고 있다. 모든 최소조치 원칙은 초음파나 육안에 의해 발견된 길이나 초음파 또는 와류탐상기(eddy current system)를 이용한 깊이에 대한 제한(limits)을 준다. 또한 침목과 이음매 또는 용접부에 관한 위치에 관한 결함의 제한이 있다. 명시된 기간은 즉각적일 수도 있으며, 보통 속도 제한이나 비상 죔쇠(Clamps)같은 경감시키는 수단에 적용될 수 있으며, 또는 더 긴 기간이 될 수도 있다. 더 긴 기간들은 수리나 레일 교체를 통하여 선로로부터 결함이 제거되어야 하는 최대의 시간이다. 본 연구에서는 Transverse Breaks, Squats, Head Checks 3가지 결함 유형에 대해 각 국에서 사용하는 최소 조치를 비교하여 분석하였다. 분석결과, 유럽에서는 레일결함에 대하여 깊이 있는 연구를 통하여 관리기준을 정하여 관리하고 있으며 이에 따라 상세하고 구체적인 레일 관리가 가능하므로 효율적이며 안전성이 제고되는 것으로 판단된다. 차후 일반철도의 180km/h 속도상승을 계획하고 있는 현 시점에서 국내철도 일반선 여건에 적합한 레일결함관리기준을 정립하기 위한 추가적인 연구가 필요할 것으로 판단된다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.5
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• pp.364-371
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• 2017

TPMS is a vehicle electric system that measures the air pressure of a tire, and informs the driver of current tire states. The TPMS sensor typically uses unidirectional communication for small size, light weight, and low power. The transmission period of the sensor indicates the service quality of monitoring the tire. In order to determine the optimal transmission period, frame collision probability and the life time of the sensor should be analyzed. In this paper, collision probability model using Venn diagram is designed in low power TPMS with the normal and warning mode. And the life time and a collision probability were analyzed with the ratio(n) of the normal mode to warning mode transmission period. As a result, $T_{nP}=31sec$ and $T_{wP}=2.4sec$ at 5 years, and $T_{nP}=71sec$ and $T_{wP}=2.5sec$ at 7 years.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.551-556
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• 2018

The material normally used in hot dip galvanizing facilities is SM45C (carbon steel for mechanical structure, KS standard), mainly because of its price. During this process, the oxidation of the plating facility occurs due to the heat of the Zn fumes coming from the molten zinc. Since the cycle time of the current facilities is 6 months, much time and money are wasted. In this study, the corrosive properties of various materials (Inconel625, STS304, SM45C) were investigated by oxidation in a high temperature and Zn fumes environment. The possibility of applying the hot-dip galvanizing equipment was investigated for each material. The Zn fumes were generated by directly bubbling Ar gas into Zn molten metal in a 650 degree furnace. High-temperature, Zn fumes corrosion was conducted for 30 days. The sample was removed after 30 days and the oxidation of the surface was confirmed with EDS and SEM, and the corrosion properties were examined using potentiodynamic polarization tests.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.207-209
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• 2015

Recently, with the economy and the information communication technology developed, the smartphone market grows continuously. The market outlook on the wireless rechargeable technology grows rapidly so that the market size is increased about six times bigger than that of the last year, and it will grow about 18 billion dollars in 2014. Because of that, as the interest on this area out focused, many kinds of technology and new product are being exploited in this field. Participants of this study were 76 mobile users in Gyeongnam and Jeonbuk province in accordance with convenience sampling. Most of the respondents about 88 percent, the wireless charger may be answered to be able to explain what it is. Also, about 70 percent of the respondents, is time to replace the future of smart phone, answered by selecting a product in consideration of the wireless charging. Based on these findings, several theoretical and practical implications were suggested.