• 한국환경복원기술학회지
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• 제17권6호
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• pp.17-27
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• 2014

Wild boars are one of the major wild life animals of which the number has increased a lot because there has been any predator and/or competitor in the Korean ecosystem. The increase of their number was a cause damaging crops in farm lands during the growing season in South Korea. This study was done to recognize the spatial pattern of farm lands damaged by wild boars. Totally 2,342 farms were known damaged by wild boars in 2012, and used to statistically analyze the perspectives of the farm land damages by wild boars in ArcMap v. 9.3. Damages by wild boars frequently happened in the western part of Gyeongnam Province including Jinju city, Tongyoung city and Namhae county. Most farm lands damaged were located nearby large mountains in this area. It might cause the number of wild boars increased in this area, which could finally stimulate the increase of farm land damaged by the species. Farm land damages by wild boars were also coincident with the preference of wild boars on their food. They preferred crops (e.g., sweet potato and corn) in uplands and rice paddies and orchards. The reason of their preference on rice, upland crops and fruits was related to the efficiency of their getting much more energy in a unit area. Another reason for the species to come into a rice paddy would be that they enjoy mud bath in there for scraping off parasites such as ticks and lice. Wild boars were seemed much overcrowded during the period from July to October when most of crops and fruits get ripen. About three-quarters of total farm land damages happened in this period. This analysis also said that 1,915 fields (81.8% of total targets) appeared within the 100-meter buffer from boundaries of mountain areas. This meant that wild boars were more sensitive to the anthropogenic land uses than we expected. They seemed to conservatively try their feeding activities in farm lands with paying attention to the human activity.

• Journal of Korean Dental Science
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• 제10권1호
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• pp.10-21
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• 2017

Purpose: The purpose of this study was to investigate the electrochemical characteristics of nanotubular Ti-25Nb-xZr ternary alloys for dental implant materials. Materials and Methods: Ti-25Nb-xZr alloys with different Zr contents (0, 3, 7, and 15 wt.%) were manufactured using commercially pure titanium (CP-Ti), niobium (Nb), and zirconium (Zr) (99.95 wt.% purity). The alloys were prepared by arc melting in argon (Ar) atmosphere. The Ti-25Nb-xZr alloys were homogenized in Ar atmosphere at $1,000^{\circ}C$ for 12 hours followed by quenching into ice water. The microstructure of the Ti-25Nb-xZr alloys was examined by a field emission scanning electron microscope. The phases in the alloys were identified by an X-ray diffractometer. The chemical composition of the nanotube-formed surfaces was determined by energy-dispersive X-ray spectroscopy. Self-organized $TiO_2$ was prepared by electrochemical oxidation of the samples in a $1.0M\;H_3PO_4+0.8wt.%$ NaF electrolyte. The anodization potential was 30 V and time was 1 hour by DC supplier. Surface wettability was evaluated for both the metallographically polished and nanotube-formed surfaces using a contact-angle goniometer. The corrosion properties of the specimens were investigated using a 0.9 wt.% aqueous solution of NaCl at $36^{\circ}C{\pm}5^{\circ}C$ using a potentiodynamic polarization test. Result: Needle-like structure of Ti-25Nb-xZr alloys was transform to equiaxed structure as Zr content increased. Nanotube formed on Ti-25Nb-xZr alloys show two sizes of nanotube structure. The diameters of the large tubes decreased and small tubes increased as Zr content increased. The lower contact angles for nanotube formed Ti-25NbxZr alloys surfaces showed compare to non-nanotube formed surface. The corrosion resistance of alloy increased as Zr content increased, and nanotube formed surface showed longer the passive regions compared to non-treatment surface. Conclusion: It is confirmed that corrosion resistance of alloy increased as Zr content increased, and nanotube formed surface has longer passive region compared to without treatment surface.

• 한국지리정보학회지
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• 제11권4호
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• pp.85-93
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• 2008

전통적으로 마을에 인접하여 인위적으로 조성되거나 관리 및 이용되어온 한국의 전통마을숲은 그 역사가 6-7세기까지 거슬러 올라간다. 마을숲 조성의 배경은 흔히 주변의 언덕, 물길과 바람통로 등 마을주변 자연환경과 관련되는 것으로 전해진다, 정착한 마을과 조성된 마을숲간의 위치관계를 지형적 유형으로 특징을 파악하고, 이를 바탕으로 "마을숲"이 "주체인 마을"의 생활환경에 어떤 기여를 하고 있는지에 대해 검토하였다. 약 500개 이상의 문헌조사와 현장 확인을 통해 전남 북지역과 경북지역 40개 마을숲에 대해 항공사진, GIS에 의한 3차원분석 등을 통해 마을숲과 마을 주변의 지형적 관계를 유형화 하고 조성 의미를 고찰하였다. 지형적 특징에 따른 유형별 마을숲은 다양한 생태계 및 생활환경개선 효과를 마을에 제공할 것으로 추정되나, 본 연구에서는 대상지의 위치적 특성이 마을 주민의 생활상에 미칠 수 있는 영향과 마을숲 조성의 효과에 기여할 수 있는 역할에 대해 살펴보았다.

• KEPCO Journal on Electric Power and Energy
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• 제5권3호
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• pp.135-140
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• 2019

Lattice towers and tubular steel poles have been commonly used for electrical power transmission in Korea. They are durable, structurally stable, simple and can easily be constructed in limited spaces. However, residents are opposed to construct transmission lattice towers in their areas because they are not visually attractive, and electrical field occur at the transmission lines. Underground transmissions have been used instead of the traditional towers to resolve these problems, however they are not cost effective to construct and run. Therefore, we have developed eco-friendly towers that are more attractive, well blending into the surrounding environment, and much more economical than underground transmissions. There are four categories of the eco-friendly electric transmission towers about design aspects. Firstly, there is decoration type such as tree tower and ensemble tower. Tree tower looks like actual trees with leaves and branches so it blends into surroundings. Ensemble towers were designed after pair of crane birds. Those towers have decoration features and art works. Structural examination and manufacturing this type would be very similar to the conventional transmission towers. Secondly, there is arm design type such as traditional tower. Design features are added to the existing towers. As partial design can be adoptable on these types, it can easily meet height regulations and attach to conventional lattice towers and tubular steel poles. Also, these towers are more economical than others. Third category is multipurpose type such as Sail Tower. These towers have simple pole or tubular structure with features which can be used as information message board, public relations and much more. This type will face greater wind pressure because of the area of the board, also visibility must take into consideration. Lastly, there is moulding type such as arc pylon. It is different shape to the conventional towers - lattice towers and tubular steel poles. Dramatic design changes have been adapted - from a hard and static tower to a soft and curved tower. These towers will well stand out in the field. However, structural examination and manufacturing this type would be difficult and costly. Also certain towers of this type would require scaffolding or false work to construct, which will result in limitations of the construction area. This paper shows KEPCO 154 kV Sail tower in detail. KEPCO 154 kV Sail tower that is included in fabrication of sample tower and tower testing has developed and the results are presented in this paper. We hope that sail tower is also considered as a solution to have public acceptance or to create a familiar atmosphere among towers and people in coastal area.

• 광물과 암석
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• 제34권2호
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• pp.147-156
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• 2021

몽골 남부 구르반사이한 호상 열도 지형 내 족도르 지역의 함동 석영맥에 대한 유체포유물 연구 결과를 보고한다. 족도르 지역에는 후기 백악기 퇴적층 내에 정치된 화강섬록 반암 내에 구조적으로 제어되는 동 광화작용이 나타난다. 이러한 화강섬록 반암 내에 동 광물 함유 석영맥은 프로필리틱 변질대의 석영-녹렴석-자철석 및 석영-자철석을 포함하는 열수 변질 양상을 보인다. 석영맥은 광물 조합에 따라 두 가지 유형으로 분류되며 주로 황동석과 함께 산출되고 드물게는 반동석, 자철석, 황철석과 함께 산출된다. 석영-자철석±황동석 및 석영-녹렴석-자철석 조합의 석영맥 내 유체포유물은 기포 크기 5-30 vol.%, 염농도 2-13 wt.% NaCl, 균질화 온도 107-270℃인 2상의 수성 포유물이다. 관찰된 석영맥의 광물 조합과 모암의 지구화학적 특성 및 변질 양상 등으로 판단했을 때, 유체포유물 자료는 연구 지역이 반암동 관련 광화작용의 프로필리틱 변질 영역에 해당함을 보여준다.

• 한국전자통신학회논문지
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• 제17권6호
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• pp.1145-1156
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• 2022

대규모 해상풍력단지 개발을 위한 입지 적합성을 효과적으로 확보하기 위해서는 개발로 인한 환경영향을 최소화하고 사회적·생태적·경제적 핵심가치에 대한 편익 상충에 대한 분석이 필수적이다. 또한 해양공간계획상 타 용도구역과 충돌하지 않도록 입지 적정성에 대한 사전검토가 반드시 선행되어야 하며, 추가로 전남 해역 인근의 풍력자원을 포함한 국지적인 기상 특성 분석도 사업타당성 조사 이전에 수행되어야 할 필요가 있다. 이에 영광군 안마도 인근 왕등여에 설치된 기상탑의 관측자료를 활용하여 풍력자원분석을 수행하였고, 해상풍력 단지 입지 관련 지리적 제약조건을 배제한 후 최적 입지구역을 선정하였다. 또한, 국지적 풍력자원 특성에 적합한 풍력단지 최적배치 결과를 WindSim 기반으로 도출하여 연간발전량을 산출하였으며, 향후 해상풍력 프로젝트의 입지발굴 및 적합지 선정에 기초연구자료로 활용하고자 한다.

• 대한의용생체공학회:의공학회지
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• 제25권2호
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• pp.157-163
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• 2004

금속 임플란트 재료들의 마모저항을 향상시키기 위하여 질소 이온주입 및 이온도금 기술을 적용하였다. 질소 이온주입 된 초내식성 스테인리스강(S.S.S)의 마모이온용출 특성을 S.S.S, 316L SS, TiN코팅된 316S SS와 비교 평가하기 위하여 탄소로 원자흡수분광분석기를 이용하여 시편들로부터 마모용출된 Cr과 Ni 이온량을 측정하였다. 또한, 저온아크증착법을 이용하여 TiN, ZrN, TiCN코팅된 Ti(Grade 2)원반의 마모저항을 비교하였고, 질소이온주입 및 질화물 코팅된 표면충의 화학적 조성은 SAES(scanning Auger electron spectroscopy)를 이용하여 분석하였다. 질소 이온주입된 S.S.S 표면으로부터 마모에 의하여 용출된 Cr과 Ni 이온량은 표면처리하지 않은 스테인리스강들에 비하여 크게 감소하였다 그러나 인공고관절에 걸리는 하중조건 하에서 실행된 마모이온용출실험에서 이온에너지 100 KeV로 질소이온 주입된 표면층은 20만회 내에서 쉽게 제거되었다. 질화물 코팅된 Ti 시편들의 마모저항도 크게 향상되었고, 그 마모특성은 코팅층의 화학적 조성에 따라 크게 차이가 났다. 코팅두께 3Um의 코팅시편들 중 TiCN 코팅된 티타늄이 가장 높은 내마모 특성을 보였으나 같은 하중조건 하에서 disk(Ti)-on-disk 마모실험에서 그 질화물 코팅면들의 마모 무게감 소비는 1만회 아래에서 모두 Ti의 마모비와 유사하게 전환되었다. 본 실험으로부터 얻어진 연구결과에 의하면, 100 KeV 질소이온주입 및 두께 3$\mu\textrm{m}$의 길화코팅된 표면층의 경우 표면 경화충의 깊이가 충분치 않아 높은 하중을 받는 임플란트의 마찰부위에 사용하기에는 한계가 있음을 보였다.