국립공원 아고산대 독립훼손지 복원식생 분포특성 및 관리방안

김종엽(Jong-Yup Kim),윤주웅(Ju-Ung Yun),한봉호(Bong-Ho Han),곽정인(Jeong-In Kwak),박석철(Seok-Cheol Park),박수영(Su Young Park),정원옥(Won-Ok Jeong) 국립공원연구원 2022 국립공원연구지 Vol.13 No.1

본 연구는 독립훼손지 중 아고산대에 위치한 지리산국립공원 세석평전과 노고단 복원식생지를 대상으로 현존식생 분석 및 식생분포 특성을 파악하여 중장기적인 모니터링 및 관리방안 수립을 위한 기초자료를 제공하고자 수행하였다. 현존식생 조사범위는 훼손지 일대 유역권분포 현황을 고려하여 설정하였으며, 세석평전 조사면적은 55,037㎡, 노고단 조사면적은 166,599㎡ 이었다. 세석평전은 초본층에 의한 식생피복도는 90% 이상 수준으로서 나지노출이 없었고, 관목층의 피복도가 60% 이상으로 안정화되어 있었다. 주요 출현수종은 구상나무, 사스래나무, 쇠물푸레나무, 철쭉, 털진달래, 붉은병꽃나무 등 식재수종과 자연적으로 이입한 자생수종이 생육하고 있었다. 노고단은 신갈나무, 호랑버들, 철쭉, 털진달래, 미역줄나무 등이 우점하는 관목식생지가 52%로 가장 넓게 분포하고 있었고, 전반적으로 식생활착 상태가 양호하였다. 노고단의 원식생은 신갈나무군락으로 추정되었고, 군부대철거지에는 귀화식물이 분포하고 있기 때문에 적극적인 관리가 필요하였다. 연구대상지는 장기적으로 주변 자연식생과 조화로운 식생경관으로 발달할 것으로 예측되었다. 향후 훼손지 복원모델은 인근 지역의 원식생을 고려하여 설정해야 할 것이지만, 복원 달성 목표는 실현가능한 수준의 목표를 설정해야 할 것이다. This study was conducted to provide basic data for mid-to long-term monitoring and establishment of management plans by analyzing the existing vegetation and identifying the vegetation distribution characteristics for the restored vegetation in Nogodan and Seseokpyeongjeon in Jirisan National Park located in the subalpine zone among the independent damaged areas. Actual vegetation survey range was established in consideration of the distribution of the watershed around the damaged area. The surveyed area of Seseokpyeongjeon was 55,037㎡, and the surveyed area of Nogodan was 166,599㎡. In Seseokpyeongjeon, the vegetation coverage by the herbaceous layer was almost 90% or more, there was no bare exposure, and the coverage of the shrub layer was stabilized at 60% or more. The main emerging tree species were planted species such as Abies koreana, Betula ermanii, Fraxinus sieboldiana, Rhododendron schlippenbachii, Rhododendron mucronulatum var. ciliatum, and Weigela florida as well as natively migrated native species. In Nogodan, the shrub vegetation dominated by Quercus mongolica, Salix caprea, Rhododendron schlippenbachii, Rhododendron mucronulatum var. ciliatum, and Tripterygium regelii was the most widely distributed with 52% of the area, and the overall diet was good. The native vegetation of Nogodan was presumed to be a cypress colony. Naturalized plants were distributed in the military base demolition site, so active management was required. The study site was predicted to develop into a vegetation landscape in harmony with the surrounding natural vegetation in the long term. In the future, the restoration model for damaged areas should be set in consideration of the native vegetation of the nearby area, but the goal to achieve restoration should be set at a feasible level.

H형강 구조물의 T-joint에서 용접조건에 따른 용접잔류응력의 영향

박정웅,박길현 朝鮮大學校 建設技術硏究所 2003 建設技術硏究 Vol.23 No.1

In the welding for the steel structures of H-beam with mild steel and 490N/mm2 high tensile steel, we applied the fillet weld mostly and 6∼8mm weld length(AISC-spec.). And a new developed metal-cored-wire is used in automatic welding as well as semi-automatic welding. In this study we have attempted to raise the welding productivity and to stabilize the quality on horizontal positions of fillet welding with the following items : We improved the weld productivity using metal based cored wire with a high deposition rate in the steel structures of H-beam. We tested the weldability and evaluated the quality of the weldmetal by horizontal fillet CO2 welding. The process is carried out in combination with a special purpose metal-based FCW with excellent resistance to porosity and high welding speed. We studied the micro structure of the weldmetal by the various welding conditions. We studied the effect of welding residual stress by the welding conditions in T-joint. Therefore, it can be assured that more productive and superior quality of the weldmetal can be taken from this study results.

니코틴과 트리암시놀론 아세토니드를 함유하는 생분해성 마이크로스피어의 제조시 분무건조법과 용매증발법의 비교

박선영,조미현,이종화,김동우,지웅길 한국약제학회 2001 Journal of Pharmaceutical Investigation Vol.31 No.4

The microspheres have been developed as a new drug delivery system. Although many particulate drug carriers, such as liposome, niosome and emulsion, have been introduced, injectable and biodegradable microspheres appears to be a particularly ideal delivery system because the local anesthesia is not necessary for the insertion of large implants and for the removal of the device after the drug release is finished. Biodegradable microspheres with nicotine and triamcinolone acetonide are prepared and evaluated. As biodegradible polymers, PLA (M.W. 15,000, PLA-0015), PLGA (M.W. 17,000, RG 502) and PLGA (M.W. 8,600, RG 502H) are used. This study attempted to prepare and evaluate the nicotine and triamcinolone acetonide-incorporated microspheres, which were prepared by two methods, solvent-evaporation and spray-drying methods. The microspheres, as a disperse system for injections, were evaluated by particle size, size distribution, entrapment efficiency, and in vitro drug release patterns. The differences of preparation method, partition coefficient, types of polymer, and preparation conditions of microspheres influence the particle size, entrapment efficiency, and in vitro drug release patterns.

등가하중법에 의해 용접변형예측을 위한 용접부 모델링기법 개발

박정웅 朝鮮大學校 建設技術硏究所 2005 建設技術硏究 Vol.25 No.1

Welding deformation causes critical problems under construction and in use of steel structures by varying the magnitude of the steel structures and deteriorating mechanic strength. Existing method to construct steel structures in civil engineering needs pre assembly process for a part of or the whole structures on a broad space to examine the size of structures inevitably varied in the process of welding (assembly process). It leads to waste of time, space and human efforts, worry of safety accidents with the characteristic of the work to be performed on a high place, and non-efficiency and non-economy by using such appurtenant equipments as crane. This paper, to remove the needless preassernbly process by pre-estimating welding deformation produced under construction of large steel structures, devises a method modeling welded part for applying the equivalence load method and examines the effects of welding sequence and self weight on welding deformation by the method.

Unbraced Tubular 아치교에서 아치리브의 단면력과 거동에 관한 연구

박정웅,유제승 朝鮮大學校 建設技術硏究所 2003 建設技術硏究 Vol.23 No.1

Arch bridge has widely been applied because it presents the beauty of unique curves to a structure, distributes horizontality the reactions due to load effectively, and makes it possible to construct economical bridges with appropriate plans. Recently, tries to transform the old types of arch bridge have been done. Of all, the most representatives are unbraced arch bridge which applies circular section of tubular to arch rib to diminish a shape factor. Some foreign countries have these bridges. In Korea, there is no examples but it has just been proposed as the plan. For the many merits of unbraced tubular arch bridge the increase in the instances applying it to construction is expected and more research is demanded. Resultingly, in this study, when the arch rib is constructed with inclined angle perpendicular to the axis of bridge to present the beauty of unbraced tubular arch bridge, the strength under the inclined angle of arch rib is examined using the Finite Element Method.

용접순서와 자중이 용접변형에 미치는 영향에 관한 연구

박정웅,강재완 朝鮮大學校 建設技術硏究所 2005 建設技術硏究 Vol.25 No.1

Welding deformations are affected by various factors. This research investigates effects of welding sequence and self-weight on welding deformation. According to the results by equivalence load method, magnitude of welding deformation with self-weight is about twice one without self-weight on parallel weld path component. But welding deformation with the components used in this research are not affected by welding sequence

백서 뇌에서 전기경련 충격에 의해 발현이 조절되는 새로운 유전자

정선주,박정은,강웅구,구영진,박주배,김용식 大韓神經精神醫學會 2000 신경정신의학 Vol.39 No.5

연구목적: 이 연구는 백서 뇌에서 전기경련 충격(Electroconvulsive shock, ECS)에 의해 발현이 조절되는 새로운 유전자를 검색하고, 발달단게 및 뇌 조직에 따른 발현양상을 관찰하기 위하여 시행되었다. 방법: 생후 7일, 21일된 어린 웅성 백서에 전기경련 충격을 가한 후 mRNS differential display-PCR(DD-PCR) 기법을 시행하여 발현의 차이를 나타내는 유전자를 검색한 후 서열분석을 실시하였다. 생후 7일 및 21일된 백서의 뇌와 성년 백서의 대뇌피질, 해마를 이용한 Northern blot 분석을 시행하여 검색된 유전자의 ECS 처치 후 시간경과에 따른 유전자 발현양상을 관찰하였다. 결과: ECS 처치군과 위충격군간에 발현의 차이를 나타낸 유전자 4개를 검색할 수 있었으며, 이중 ECS에 의해 발현이 증가되는 1개의 유전자를 선정하여 서열분석을 실시한 결과 EST 서열만이 보고된 새로운 유전자임이 밝혀졌다. 이 유전자는 생후 7일된 백서의 뇌에서는 ECS 처치 후 180분에 발현양의 증가가 최고치에 도달하였으나, 생후 21일된 백서의 뇌와 성년백서의 대뇌피질 및 해마에서는 360분 경과시까지 지속적으로 발현 양이 증가하였다. 결론: 이같은 결과는 ECS에 의해 생체 내에서 유전자 발현의 조절이 이루어짐을 시사하며, 향후 이러한 유전자의 세포 내 기능에 관한 연구를 시행함으로써, ECS에 의한 생체의 반응과 치료기전에 대한 이해를 넓힐 수 있을 것으로 기대된다. 중심단어:전기경련 충격·DD-PCR·유전자·백서 뇌. Objectives: This study was performed to identify genes regulated by electroconvulsive shock (ECS) and to observe the pattern of expression of genes according to different developmental stages and brain regions. Method: ECS(130V, 0.5 sec) was given to male Sprague-Dawley rats with age of postnatal day 7 and 21(P7, P21 respectively). After screening genes regulated by ECS with mRNA diffe-rential display-PCR(DD-PCR), we selected one clone among them and observed the induction of this gene after ECS by time-dependent Northern blot analysis of rat brain of P7, P21 and adult rat cortex and hippocampus. Results: By DD-PCR method, we have identified four clones whose expression was regulated by ECS. Among them, one(CP 10-2) was proved to be a new gene by sequencing and BLAST search. Its expression was increased after ECS in P7, P21, and adult rat brain. The expression of CP 10-2 reached peak level at 180 minutes after ECS in P7 rat brain, but was further increased until 360 minutes after ECS in P21 and adult rat brain. Conclusion: In this study, a new gene was identified in rat brain which showed up-regulated expression in response to ECS. Cloning and characterization of this new gene would be helpful to elucidate the effect of ECS in rat brain. KEY WORDS:Electroconvulsive shock·Differential display-PCR·Gene·Rat brain.

The effect of initial stress induced during the steel manufacturing process on the welding residual stress in multi-pass butt welding

Jeong-ung Park,Gyubaek An,Wanchuck Woo 대한조선학회 2018 International Journal of Naval Architecture and Oc Vol.10 No.2

A residual stress generated in the steel structure is broadly categorized into initial residual stress during manufacturing steel material, welding residual stress caused by welding, and heat treatment residual stress by heat treatment. Initial residual stresses induced during the manufacturing process is combined with welding residual stress or heat treatment residual stress, and remained as a final residual stress. Because such final residual stress affects the safety and strength of the structure, it is of utmost importance to measure or predict the magnitude of residual stress, and to apply this point on the design of the structure. In this study, the initial residual stress of steel structures having thicknesses of 25 mm and 70 mm during manufacturing was measured in order to investigate initial residual stress (hereinafter, referred to as initial stress). In addition, thermal elastic plastic FEM analysis was performed with this initial condition, and the effect of initial stress on the welding residual stress was investigated. Further, the reliability of the FE analysis result, considering the initial stress and welding residual stress for the steel structures having two thicknesses, was validated by comparing it with the measured results. In the vicinity of the weld joint, the initial stress is released and finally controlled by the weld residual stress. On the other hand, the farther away from the weld joint, the greater the influence of the initial stress. The range in which the initial stress affects the weld residual stress was not changed by the initial stress. However, in the region where the initial stress occurs in the compressive stress, the magnitude of the weld residual compressive stress varies with the compression or tension of the initial stress. The effect of initial stress on the maximum compression residual stress was far larger when initial stress was considered in case of a thickness of 25 mm with a value of 180 MPa, while in case of thickness at 70 mm, it was 200 MPa. The increase in compressive residual stress is almost the same as the initial stress. However, if initial stress was tensile, there was no significant change in the maximum compression residual stress.

The effect of initial stress induced during the steel manufacturing process on the welding residual stress in multi-pass butt welding

Park, Jeong-ung,An, Gyubaek,Woo, Wanchuck The Society of Naval Architects of Korea 2018 International Journal of Naval Architecture and Oc Vol.10 No.2

A residual stress generated in the steel structure is broadly categorized into initial residual stress during manufacturing steel material, welding residual stress caused by welding, and heat treatment residual stress by heat treatment. Initial residual stresses induced during the manufacturing process is combined with welding residual stress or heat treatment residual stress, and remained as a final residual stress. Because such final residual stress affects the safety and strength of the structure, it is of utmost importance to measure or predict the magnitude of residual stress, and to apply this point on the design of the structure. In this study, the initial residual stress of steel structures having thicknesses of 25 mm and 70 mm during manufacturing was measured in order to investigate initial residual stress (hereinafter, referred to as initial stress). In addition, thermal elastic plastic FEM analysis was performed with this initial condition, and the effect of initial stress on the welding residual stress was investigated. Further, the reliability of the FE analysis result, considering the initial stress and welding residual stress for the steel structures having two thicknesses, was validated by comparing it with the measured results. In the vicinity of the weld joint, the initial stress is released and finally controlled by the weld residual stress. On the other hand, the farther away from the weld joint, the greater the influence of the initial stress. The range in which the initial stress affects the weld residual stress was not changed by the initial stress. However, in the region where the initial stress occurs in the compressive stress, the magnitude of the weld residual compressive stress varies with the compression or tension of the initial stress. The effect of initial stress on the maximum compression residual stress was far larger when initial stress was considered in case of a thickness of 25 mm with a value of 180 MPa, while in case of thickness at 70 mm, it was 200 MPa. The increase in compressive residual stress is almost the same as the initial stress. However, if initial stress was tensile, there was no significant change in the maximum compression residual stress.

Influence on properties of base metal after elimination of lifting-lug member in a dissimilar welding between steel base and steel lifting lug

Jeong-ung Park,Gyubaek An,Hae Woo Lee 대한조선학회 2019 International Journal of Naval Architecture and Oc Vol.11 No.2

The increasing demands of lifting lugs can be attributed to the rapid advancement of shipbuilding and offshore-structure production technologies and an exponential increase in the size of the block units of ship structures. Therefore, to ensure safety during the transportation and turnover of large blocks, it is important to determine the structural integrity and position of lifting lugs. However, because the manufacturing cost and availability of lugs are important considerations, low cost and easily obtainable steel compositions of grades different from those of the blocks are often used as alternatives. The purpose of this study is to investigate the effect of a lifting-lug metal on the physical properties of a base metal in a dissimilar welding between the base metal and lifting lug. The effect was evaluated by observing the metal microstructures and determining the hardness and dilution values on the crosssectional surface of the lifting lug. According to the results of the metal microstructures, impact, hardness, and emission spectrochemical analysis at the surface from where the lug was removed confirmed that the chemical composition of the lifting-lug metal did not influence the physical properties of the base metal.