• 한국가구학회지
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• 제24권4호
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• pp.444-451
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• 2013

In this paper, experimental results were presented on the moment resistance of a concealed timber post base joint aimed at replacing in a modern design introduced lately the wood to wood joints used in the traditional Korean timber house - Hanok. Preliminary results showed that the original configuration of the joint offers a limited moment resistance and a low ductility and energy dissipation. In an attempt to mitigate those limitations without undergoing major changes in the connector, three new configurations were proposed and investigated. Motivated by the wish to prevent the early failure in welds, a first approach consists in directly bolting the connector's upper plate to lower the stress on the weak welds. Alternatively, another approach focused on increasing the strength of these welds by extending their length to the full width of the metal wings. Finally, a third configuration investigated the effect of those two approaches combined. In conclusion, reinforcing the welds found out to be the best option among the presented ones. As a result, this connector considered to show proper ability for use in earthquake-resistant structures with suited lateral-resistant structural elements.

• 농업과학연구
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• 제49권4호
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• pp.983-993
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• 2022

The purpose of this study is to provide information on a forest healing environment using the analysis of nature volatile organic compounds (NVOCs) and thermal comfort in Chungnam National University Experimental Forest, with the aim of using the Experimental Forest as a healing environment for health promotion. We analyzed NVOCs and thermal comfort of Chungnam National University Experimental Forest measured on September 12^th, 2021. As a result of the NVOC analysis, a total of seven substances were detected, mainly including alpha pinene and beta pinene. The detection amount for each time period was highest at the time of sunset. The thermal comfort was analyzed by time-dependent changes and changes according to clothing and exercise amount. The results showed that the predicted mean vote of the experimental forest is within the range of 'slightly cool' and 'slightly warm' sensation, and thus a comfortable thermal environment could be controlled by the amount of clothing and activity. Based on the analysis, this study provides information on the healing environment of the experimental forest at Chungnam National University. It also indicates that the forest can be used as a health promotion and healing environment with thermal comfort by composing a physical activity program of appropriate intensity for each time period.

• Journal of the Korean Wood Science and Technology
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• 제41권5호
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• pp.399-405
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• 2013

This study demonstrates the utilization of light microscopy and Fast Fourier Transform-Peak Finding (FPF) method for microfibril angle (MFA) measurement from unstained sections of red pine (Pinus densiflora). To obtain an image with optimal contrast and resolution for MFA measurement, effects of numerical aperture (NA) of condenser lens and color filters were investigated. About 60% of NA of the maximum condenser NA produced an image with optimal contrast, but a color filter with short wavelength range (DAPI) created images with improved resolution. Manual angle measurement and the FPF method were applied to the image with optimal contrast for MFA measurement. The experimental results from the FPF method were considered to be more repeatable and less subjective than those from the manual angle measurement.

• Journal of the Korean Wood Science and Technology
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• 제37권6호
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• pp.524-530
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• 2009

기둥-보 구조와 경골목구조가 혼합된 공법은 경골목구조가 심벽 또는 평벽 요소로써 구조내력성능의 대부분을 차지하고 있다. 경골목구조의 수평전단내력성능은 면재에 대한 못접합부의 전단성능으로부터 예측할 수 있으며, 못접합부는 못의 휨내력성능을 이용하여 예측할 수 있다. 못접합에 의한 내력벽의 항복내력과 벽체 강성을 예측하기 위한 기초 연구로써 못의 휨내력성능을 이용한 못접합부의 항복내력 및 접합계수(초기강성)를 검토하였다. 못접합부 내력성능 예측에는 각각의 주부재에 대해 일반 지압내력 및 지압강성을 이용하고, 파스너인 나선형 철선못의 휨시험에 의한 휨항복내력성능을 이용하였다. 홈가공부의 지름에 의한 항복내력은 예측 정밀성이 우수하였으나, 접합계수는 낮게 예측되었다. 그 원인으로 주부재에서는 비중의 영향, 측면부재에서는 못머리지름에 의한 인발, 접합부에서는 못머리부의 지압 및 모멘트저항 등이 영향을 끼침을 알 수 있었으며, 이에 대한 차후 검토가 요구된다.

• 한국산림과학회지
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• 제90권1호
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• pp.90-104
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• 2001

이 연구는 지난 3년간 북경임업대학교와 공동연구과제로 중국의 사막화방지 및 방사기술개발을 위한 연구의 일환으로 사막화현황 및 녹화기술수준조사 및 평가를 위하여 수행되었으며, 특히 본고에서는 중국의 황막사지에 대한 녹화기술을 분석하고자 하였다. 사막화지역 식생분포의 일반적인 특징은 부분적으로 집중된 식생분포, 즉 사막의 저지대 또는 분지의 낮은 곳의 사구에 있는 사막식물, 염수호 주변의 내염성식물, 담수 염수호와 하천연안의 포플러 및 위성류의 군생, 사력퇴적지(고비)의 사퇴식생, 하천선상지의 초생지 및 오아시스(녹주(綠洲))숲 등이다. 일반적으로 사막화지역에는 중국식물명(中國植物名)으로 정류(檉柳)(홍류(紅柳))(Tamarix chinensis Lour.), 사사(梭梭)(Haloxylon ammodendron Bunge.), 사괴조(沙拐棗)(Calligonum Spp.), 호루(胡楊)(Populus euphratica Oliver.), 사조(沙棗)(Elaeagnus angustifolia L.), 유(楡)백유(白楡)(Ulmus pumila L.), 류류(柳類)(Salix spp.), 암황시(岩黃蓍)(Hedysarum spp.), 금계아(錦鷄兒)(Caragana spp.), 문관과(文冠果)(Xanthoceras sorbifolia Bunge.), 백자(白刺)(Nitraria tangutorum Bobr.), 호기자(胡技子)(Lespedeza bicolor), 낙타자(駱駝刺)(Alhagi sparsifolia Shap.), 자산감(刺山柑)(Capparis spinosa L.), 사호(沙蒿)(Artemisia arenaria DC.) 등이 널리 분포하며, 이와 같은 사막화지역 자생식물에 관한 연구가 더욱 필요한 상황에 있다. 풍식지역에서는 합리적인 경작체계(지역계획, 방풍림체계 및 오아시스보호체계, 관개수로네트워크설치, 광대한 농지관리기술 등), 식물자원의 합리적 이용기술(연료림, 약용식물, 방목, 초지관리 등), 수자원이용(유역계획 및 관리, 수로건설, 절수관개기법 등), 방풍림조성, 인구증가의 조절, 농용림 연료목 사료증산기술 등에 관해서, 그리고 수식지역에서는 합리적인 토지이용기술, 식생이용기술, 공학적기술, 농작물보호기술 개발 등에 관한 시험연구사업이 중점적으로 추진되고 있다. 또한, 사막화지역에서의 염성토양 알카리토양개량을 위한 수리적(관개, 배수, 세탈, 수도재배 등), 농업적(토지정리, 경작, 시비, 파종, 윤작, 혼작, 객토 등), 생물적(내염성 작물 및 녹비의 재배, 조림 등) 방법 등에 관한 시험연구도 활발하게 추진되고 있으며, 이와 같은 사막화지역의 녹화사업에 국제적인 협력을 절실하게 요망하고 있다.

• 한국산림과학회지
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• 제76권3호
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• pp.243-248
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• 1987

The U.S. Forest Service administers the world's largest forestry research organization. From its modest beginning in 1876, some 30 years before the United States national forest system was established, the research branch has devoted its effort to meet current and future information needs of the forestry community of the United States, not just for the U.S. Forest Service. The research branch is one of three major administrative units of the U.S. Forest Service. The others being the National Forest System and State and Private Forestry. Currently the National Forest System comprises 155 national forests, 19 national grasslands, and 18 utilization projects located in 44 states. Puerto Rico, and the Virgin Islands. The National Forest System manages these areas for a large array of uses and benefits including timber, water, forage, wildlife, recreation, minerals, and wilderness. It is through the State and Private Forestry branch that the U.S. Forest Service cooperates and coordinates forestry activities and programs with state and local governments, forest industries, and private landowners. These activities include financial and technical assistance in disease, insect, and fire protection ; plan forestry programs ; improve harvesting and marketing practices ; and transfer forestry research results to user groups. Forestry research is carried out through eight regional Forest Experiment Stations and the Forest Product Laboratory. Studies are maintained at 70 administrative sites, and at 115 experimental forest and grasslands. All of the current sciences that composed modern forestry are included in the research program. These range from forest biology (i. e. silviculture, ecology, physiology, and genetics) to the physical, mathematical, engineering, managerial, and social sciences. The levels of research range from application, developmental, and basic research. Research planning and priority identification is an ongoing process with elements of the research program changing to meet short-term critical information needs(i. e. protection research) to long-term opportunities(i. e. biotechnology). Research planning and priority setting is done in cooperation with National Forest Systems, forest industries, universities, and individual groups such as environmental, wilderness, or wildlife organizations. There is an ongoing review process of research administration, organization, and science content to maintain quality of research. In the U.S. Forest Service the research responsibility is not completed until the new information is being applied by the various user group : I. e. technology transfer program. Research planning and development in the U.S. Forest Service is a dynamic activity. Porgrams for the year 2000 and beyond are now in the planning stage.

• Journal of the Korean Wood Science and Technology
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• 제38권2호
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• pp.108-116
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• 2010

This paper explains the effects of wood drying on treatability (as determined by water uptake) of Japanese red pine (Pinus densiflora S. et Z.) at the sevenmoisture content (MC) levels above and below the fiber saturation point (FSP). According to the experimental results, it was found that water uptake (as the percentage of void volume filledwith distilled water, VVF%) was influenced by level of moisture content and percentage of void volume filled was improved effectively by kiln drying process. A significant relationship between moisture content and treatability was established. Permeability and liquid uptake were decreased above the FSP due to the effect of the less void space available in wood. Even though increased liquid uptake was observed at lower moisture content, no significant differences was observed moisture content below 20%. Therefore, this species need to be initially dried below FSP before treated with liquids. But drying moisture content below 10% might not be economical for the commercial purpose comparing drying the wood between 10 and 20% moisture content. The result of this study inferred that the treatability of pine wood can be improved by reducing the moisture content up to a certain level of 10~20% for allowing better performance.

• 한국산학기술학회논문지
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• 제19권7호
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• pp.112-124
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• 2018

본 연구는 유아의 숲동화 구연학습이 자기감정조절과 공동체의식 함양에 미치는 효과를 밝히는데 목적을 갖고 S시소재 유아 40명을 대상으로 8주간 16회기 실험 연구 하였다. 연구결과 전체적으로 숲동화 구연학습을 한 실험집단이 통제집단보다 높게 나타나 실험집단의 숲동화 구연학습의 유용성을 입증해주었다. 특히 공동체의식 요인의 기본생활 습관과 공동체 의식, 사회성발달, 자기인식에서 모두 실험집단이 비교집단에 비해 높게 나타났다. 이는 숲 체험 활동에서의 자연과에서 소통과 함께 동화소재를 자연 속에서 읽으면서 듣고 직접 체험함으로써 유아들이 동화를 통해 주의 집중하고 자연과의 교감 속에 자연 그대로 느끼는 순수한 감성을 바탕으로 또래와 함께 상호 협력하고 공존을 위한 관계 향상은 물론 원칙과 질서를 지키고 이를 실천하려는 소중한 마음이 동화 속 이야기와 함께 자기감정조절까지 증가시킴을 실증해준 것으로 볼 수 있다. 이같은 결과는 숲 활동에 있어 단순한 놀이나 교육 중심에서 벗어나 숲동화 연계 활동을 통해 감정조절 뿐만 아니라 공동체의식 향상에도 긍정적인 교육효과를 가져다 줌에 따라 이의 활용이 보다 확산될 필요가 있음을 시사한 것으로 평가할 수 있다.

• Nuclear Engineering and Technology
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• 제55권11호
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• pp.3973-3982
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• 2023

As for two-phase flow in rectangular channels, the flow regimes especially like churn-turbulent and annular flow are significant for the physical problem like Countercurrent Flow Limitation (CCFL). In this study, the rectangular channels with cross-sections of 4 × 66 mm, 6 × 66 mm, 8 × 66 mm are adopted to investigate the flow regimes of air-water vertical upward two phase flow under adiabatic condition. The gas and liquid superficial velocities are 0 ≤ j_g ≤ 20m/s and 0.25 ≤ j_f ≤ 3m/s respectively which covering bubbly to annular flow. The flow regimes are identified by random forest algorithm and the flow regime maps are obtained. As the results, the transitional void fraction from slug to churn turbulent flow fluctuate from 0.47 to 0.58 which is significantly affected by the dimensional size of channel and flow rate. Besides, the void fraction at transitional points from churn-turbulent (slug) to annular flow are 0.66-0.67, which are independent with the gap size. Furthermore, a new criteria of slug to churn-turbulent flow is established in this study. In addition, by introducing the interfacial force model, the criteria of churn-turbulent (slug) flow to annular flow is verified.

• 한국환경복원기술학회지
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• 제18권6호
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• pp.201-214
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• 2015

This study was conducted to identify forest topsoil's usefulness from July 2013 to Oct 2014. Generally, there are abundant seeds in topsoils and it can be used at restoration works. Mt. GARIWANG is famous for biodiversity in Korea. This study was aimed to find out the suitable utilization methods of natural topsoils for restoration works at sky-slopes construction sites. Test beds was made to identify suitable collecting times and suitable topsoil thickness. The main results are summarized as follows. First, Mt. GARIWANG have diverse species and in topsoils we can find lots of burried seeds which can be used at restoration works. Second, according to indoor experiment, as the depth of topsoil used thicker, the number of plants and coverage rates were increased. Also, there were no distinct differences in coverage rates between 5cm and 8cm thick topsoil plots and it can be possible to use at least 3cm thick topsoils even thou lower coverage rates. Third, as the results of research about indoor and outdoor experimental plots, there were difference in plant emergency. If we use the stabilizer to protect soil erosion, then we can get more increased results at sloped outdoor experimental plots. Fourth, based on environmental impact assessment, there was 389 species in whole region of Mt. GARIWANG. Through this seed bank experiments, we can find 23 varieties, including 4 tree varieties and 19 herbaceous varieties. We can find lots of native herbaceous species from topsoils. Fifth, this research was done at the specific area of Mt. GARIWANG and used limited topsoils. But we monitoring more longer periods, then there will be more useful outcomes. Finally by researching topsoils of Mt. GARIWANG, we can find diverse native plants. Thus, we must reuse natural topsoils of Mt. Gariwang for restoration of original vegetation.