• Journal of the Korean GEO-environmental Society
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• v.24 no.2
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• pp.25-30
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• 2023

The high-strength rockfall net developed in this study is to replace the fallout prevention net method using PVC coating net made of core wire thickness 3.2 mm and tensile strength 290-540 MPa class steel wire. General PVC coating net have low performance, and in the event of falling rocks or surface loss, they cannot withstand the load and are torn, which rather adds to the damage. Developed rockfall net was manufactured using steel wires with a core wire thickness of 2.8 to 3.2 mm and a tensile strength of 1,000 to 2,000 MPa. Test method was referred to the international standard Steel wire rope net panels and rolls-Definitions and specifications (ISO 17746:2016), and was conducted in accordance with the provisions of the punching test. Through indoor punching tests, the load-displacement curves of the general PVC coating network and the developed high-strength capture net (1,000 and 2,000 MPa) were compared, and the maximum Pull-out load was analyzed to be improved by 324.47% (2,000 MPa high-strength net).

• Journal of Aerospace System Engineering
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• v.14 no.3
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• pp.10-16
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• 2020

We propose a capture mechanism based on the principles of fishing nets that can be mounted on the drone using cable. The gripper mechanism, mainly proposed for the drone is heavy, and is limited to catch standardized objects. In contrast, the proposed capture device in this paper is light, flexible, and can capture various types of objects from a long distance. The theoretical relationships between cables and mechanisms were analyzed. Finally, the capture device was designed and manufactured to be installed in the drone (DJI S900) to conduct capturing experiments for various objects and verify the validity.

• Journal of the Korean GEO-environmental Society
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• v.24 no.3
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• pp.15-21
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• 2023

Although standards related to falling stone facilities are established in Korea, the absorption energy of the rockfall prevention net is evaluated from the passage of rockfall and destruction of the rockfall prevention net on field test. The existing PVC coating net does not sufficiently suppress the rockfall load and tears frequently occur, and a high-strength wire rockfall net was developed to prevent. In this study, the performance was analyzed through field tests of the existing PVC coating net and the developed high-strength rockfall net (1,000 MPa, 2,000 MPa).

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.04a
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• pp.215-216
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• 2002

간이 측정기에 대한 연구는 실내공기 오염의 연구에서 인체가 작업장에서 실내 대기오염물에 노출이 되는 정도를 평가하기 위하여 개발되었다. 처음에는 주로 포름알데히드나 이산화질소를 측정하기 위하여 개발되었으나, 최근에는 오존을 측정하는 방법으로도 개발되고 있다. 오존을 측정하는 간이 측정기의 개발을 위해서는 오존과 선택적으로 그리고 정량적으로 반응하여 오존을 포획하는 시약을 선정하는 작업과 이때 사용된 포집용 filter 선정의 작업이 중요하다. 또한 오존 포획 담체의 분석 방법도 중요한데, 간이 측정기를 통하여 경제성을 높이고 별다른 후처리 작업 없이 현장에서 바로 색도 변화로 오존을 분석할 수 있는 방법이 추천되는 추세이다. (중략)

• The Journal of the Petrological Society of Korea
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• v.13 no.1
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• pp.34-45
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• 2004

This paper describes the textural relations of mantle xenoliths and fluid inclusions in mantle-derived rocks found in alkaline basalts from Jeju Island which contain abundant ultramafic, felsic, and cumulate xenoliths. Most of the ultramafic xenoliths are spinel-lherzolites, composed of olivine, orthopyroxene, clinopyroxene and spinel. The felsic xenoliths considered as partially molten buchites consist of quartz and plagioclase with black veinlets, which are the product of ultrahigh-temperature metamorphism of lower crustal materials. The cumulate xenoliths, clinopyroxene-rich or clinopyroxene megacrysts, are also present. Textural examination of these xenoliths reveals that the xenoliths are typically coarse grained with metamorphic characteristics, testifying to a complex history of evolution of the lower crust/upper mantle source region. The ultramafic xenoliths contain protogranular, porphyroclastic and equigranular textures with annealing features, indicating the presence of shear regime in upper mantle of the Island. The preferential associations of spinel and olivine with large orthopyroxenes suggest a previous high temperature equilibrium in the high-Al field and the original rock-type was a Al-rich orthopyroxene-bearing peridotite without garnet. Three types of fluid inclusions trapped in mantle-derived xenoliths include CO$_2$-rich fluid (Type I), multiphase silicate melt (glass ${\pm}$ devitrified crystals ${\pm}$ one or more daughter crystals ＋ one or more vapor bubbles) (Type II), and sulfide (melt) inclusions (Type III). C$_2$-rich inclusions are the most abundant volatile species in mantle xenoliths, supporting the presence of a separate CO$_2$-rich phase. These CO$_2$-rich inclusions are spatially associated with silicate and sulfide melts, suggesting immiscibility between them. Most multiphase silicate melt inclusions contain considerable amount of silicic glass. reflecting the formation of silicic melts in the lower crust/upper mantle. Combining fluid and melt inclusion data with conventional petrological and geochemical information will help to constrain the fluid regime, fluid-melt-mineral interaction processes in the mantle of the Korean Peninsula and pressure-temperature history of the host xenoliths in future studies.

• Proceedings of the KSEEG Conference
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• 2000.04b
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• pp.325-326
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• 2000

• Korean Journal of Environment and Ecology
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• v.30 no.1
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• pp.48-57
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• 2016

The distribution of fish (Cobitidae and Cyprinidae) and amphibians together with related environmental factors were surveyed at 30 randomly selected rice-fields (15 flooded unmanaged rice fields (FUR) and 15 unflooded managed rice fields (UMR)) near the Yedang reservoir in Korea, eight times from May to August in 2012. The total number of species captured from the entire survey area was 13 species with 8 families of fish and 5 species of amphibians. The number of species of Cyprinidae fish captured in FUR was higher than that in UMR. Upon the comparative analysis on the distribution of fish and amphibians in FUR and UMR, it was found that the number of Cyprinidae fish captured in FUR was significantly higher than that in UMR while the number of Cobitidae fish captured in UMR was higher than that in FUR. According to the analysis on the environmental factors that affect the distribution of fish, Cyprinidae fish tend to appear in rice-fields, that were flooded in winter, near the Yedang reservoir while Cobitidae fish tend to appear in rice fields that draws its water supply from forest reservoir and have a good water drainage system. In case of amphibians, the number of tadpoles captured in UMR was higher than that in FUR. Rana catesbeiana was dominant in FUR and Rana nigromaculata was dominant in UMR. Upon the analysis on the environmental factors that affect the distribution of tadpoles, it was found that Rana catesbeiana tadpoles tend to appear in rice fields, that were flooded in winter, near Yedang reservoir while Rana nigromaculata tadpoles tend to appear near mountains and far from the Yedang reservoir.

• Journal of IKEEE
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• v.1 no.1 s.1
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• pp.73-82
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• 1997

In this paper we analyzed, using Markov modeling, the performance of CSMA/CD over the wireless channel which is characterized by near-far effect, shadowing and Rayleigh fading. The analysis shows that throughput of CSMA/CD is degraded by channel error. However, if capture effect which arises from the randomness of power level of received signal due to the fading phenomena of electromagnetic waves is taken into consideration, the system performance is much improved and the system stability is also made better.

• Bulletin of Korea Environmental Preservation Association
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• s.400
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• pp.22-25
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• 2012

사전환경성검토와 환경영향평가의 통합, 야생동 식물 불법포획 처벌 강화, 소형가전제품 분리배출제 도입, 신규건축물 및 숙박 목욕장 골프장의 절수설비 기준 강화 등 2012년 7월부터 달라지거나 새롭게 시행되는 주요 환경행정 내용을 정리하였으니 업무에 참고하시기 바랍니다.

• Nuclear industry
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• v.5 no.7 s.29
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• pp.48-51
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• 1985

고전환경수로란 전환율, 즉 어미물질의 중성자포획에 의한 핵분제성물질생성량과 그 소비량의 비가 $0.8\~1.0$의 범위에 있는 경수로로서 종래의 경수로 약 0.6과 비교하면 전환율이 높은 것이 특징이다.