• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 가을 학술발표회 논문집
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• pp.271-278
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• 2002

Soft ground has complex features in mechanic character of ground. Some problems about the settlement and transformation occur if the ground strength is comparatively weak and the depth is large. Therefore, we should consider physical and mechanical characters for safe, economical design and management. As the result of the course, we can compare them with those of field then solve the limitations which were came from the complex character of the soft ground. I have considered the soil's physical character (specific gravity of soil particles, moisture content, grain-size analysis etc) and mechanical character (direct shear test, consolidation, triaxial shear test etc), and then make out a linear interpolation by regression using the two, those and connection of the depth

• Journal of the Korean Wood Science and Technology
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• 제48권5호
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• pp.618-630
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• 2020

Muna teakwood, especially from old stands, has been popular as raw material for timber industries in Indonesia for the past ten decades. Due to the scarcity of this wood, superior-grown seedlings of Muna teakwood have been developed and widely planted. Since there is no information on its characteristics, therefore, the aim of this research was to investigate wood characteristics of the 8-year-old superior-grown teak from Muna Island to ensure their proper utilization as raw material for wooden furniture. Wood discs and boards from basal area of three different trees were used as the samples. Macroscopic and microscopic anatomical characteristics were observed following the IAWA's list, while their physical-mechanical properties were measured following British Standard 373-57. Results showed that anatomical characteristics of this wood sample are similar to regular teakwood, but its heartwood portion is higher. Differences among trees are found in regards to wood texture, growth ring width, as well as early and latewood portion. The green moisture content was lower than that of fast-growing teak of a similar age. The wood is more stable than the old teakwood, but its specific gravity is lower. In general, mechanical properties of this wood were higher than those of the regular fast-growing teakwood, but lower than the old one. Based on its specific gravity, this superior Muna teakwood was categorized as a Strength Class of III. The wood is suitable enough for wooden furniture manufacturing.

• Journal of Chest Surgery
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• 제44권3호
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• pp.197-207
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• 2011

Background: In cardiac surgery, especially in the reconstruction of vascular structures and intracardiac defects, glutaraldehyde has usually been used as the reagent for fixing porcine or bovine pericardial tissues. But the well-known problem of calcification or cytotoxicity of glutaraldehyde motivates the search for a replacement. The aim of this study is to investigate the physical, mechanical, and biochemical characteristics of bovine pericardial tissues fixed with genipin, which is known to be a less toxic and more natural fixing reagent. Materials and Methods: Bovine pericardial tissues were fixed with different concentrations and conditions of glutaraldehyde and genipin. To determine the physical, mechanical, and biochemical differences among different concentrations and conditions, we divided the tissue into 18 groups by concentration, the addition of organic solvents, and the timing of adding the organic solvents, and compared the characteristics of each group. Results: Tensile strength, physical activity, and thermal stability tests revealed that the tissues fixed with glutaraldehyde were better with regard to mechanical strength and biochemical durability. However, the difference was not significant statistically. Conclusion: Genipin can be used as an alternative crosslinking agent for pericardial tissue, considering given its physical, mechanical, biochemical characteristics and low cytotoxicity comparable to glutaraldehyde. However, further studies are needed on the immune reaction and the long term changes in genipin-fixed tissues in the human body.

• Journal of the Korean Wood Science and Technology
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• 제44권5호
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• pp.767-775
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• 2016

목재의 재질특성은 토양, 지형, 강우, 기후변화 등의 환경적 인자뿐만 아니라 임분 특성에 의해서도 바뀌게 된다. 지역 성림기원에 따라 종가시나무 목재의 물리 역학적 특성을 비교 검토하였다. 지역에 따른 비교분석은 전라남도와 제주도의 종가시나무 천연림을 대상으로 실시하였다. 지역에 따른 결과에서 제주지역은 전남지역에 비하여 높은 생장률을 나타내었으며 역학적 특성에서는 휨강도를 제외한 여러 역학적 특성에서 상관관계가 인정되었으나 실제 값으로 볼 때 큰 차이는 나타나지 않았다. 또한 성림기원에 따른 결과에서는 생장률 및 역학적 특성에서 특별한 차이가 나타나지 않았다.

• Journal of the Korean Wood Science and Technology
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• 제43권6호
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• pp.714-720
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• 2015

목재의 물리, 역학적 특성은 토양, 기후변화 등의 환경적 인자뿐만 아니라 임분특성에 의해서도 바뀌게 되므로 남부 세 지역의 임분특성이 목재의 재질특성에 미치는 영향과 지역별 물리, 역학적 특성 등을 비교 검토하였다. 전남, 제주도의 구실잣밤나무 임지에 대하여 임분특성과 목재재질특성을 평가 분석하였는데 이들 간에는 대부분 높은 상관관계가 나타났다. 구실잣밤나무의 기건밀도의 물리적 특성과 휨, 압축, 전단강도의 역학적 특성은 임분 특성에서 흉고직경과는 부의 상관관계를 나타내었고 표고, 배수와는 정의 상관관계를 나타내었으며 모든 부분에서 유의성이 나타났다. 또한 물리 역학적 특성에서도 지역별로 차이가 나타났다. 본 연구의 목재 재질특성 분석결과, 남부지역의 구실잣밤나무는 난대 지역의 유용한 산림자원으로 활용할 수 있을 것으로 생각된다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1491-1495
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• 2004

For the evaluation of the mobile robot performance in complex environments, the experimental approach in an actual physical environment has been commonly taken. In the physical experimental approach, however, it is quite difficult to define the proper environment for the evaluation due to the lack of commonly agreed characteristics of the test environment. Particularly the number of combinations of types and physical parameters of the obstacles that the mobile robot is expected to deal with is practically unlimited. In an effort to simplify and improve the effectiveness of the evaluation process, we propose an evaluation method using decomposed environmental elements, where we evaluated the performance of the robot for a small group of simple and decomposed obstacle components, for examples projection and slope, instead of a large group of complicated random obstacles. The paper describes a set of simple obstacle models and performance parameters that we have chosen for the effective evaluation process. As an alternative to the physical experimental evaluation approach, in this paper, we used a virtual evaluation environment where the robot and the physical test environment has been modeled using a commercial multi-body dynamics analysis packaged called RecurDyn.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.655-662
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• 2000

This study concerns with the variation of engineering characteristics of soft ground under embankment treated vertical drains. The derived engineering characteristics can be used in the prediction of increased strength of soft ground treated with vertical drains. The variations of physical properties such as liquid limit, natural water content, void ratio, and dry unit weight, and mechanical properties such as strength, preconsolidation ratio, compressibility are analysed and suggested. The co-relation of physical properties and mechanical properties with installation of vertical drains in soft ground are derived in this study.

• 한국지반공학회논문집
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• 제30권11호
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• pp.39-49
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• 2014

제주도의 화산암은 여러 환경적인 요인으로 인하여 크기와 분포가 다양한 기공이 많은 다공상 구조를 보이고 있으며, 지질학적 그리고 역학적 특성 또한 지역마다 차이를 나타내고 있다. 제주도 화산암에 대한 지질학적/화학적 특성에 대한 연구 및 물리적/역학적 특성에 대한 연구는 많은 연구자에 의해 활발히 이루어져 왔지만, 제주도 화산암의 물리적 및 역학적 특성에 대한 종합적인 비교 분석은 이루어져 있지 않다. 본 연구에서는 제주도 화산암에 대하여 기존에 발표된 연구논문 및 보고서를 통하여, 제주도 화산암에 대한 물리 역학적 특성의 상관관계를 종합적으로 비교 분석하였다. 그 결과 흡수율 및 공극률과 겉보기 비중과의 관계는 일반적으로 선형의 관계에 있으며, 여러 환경적 요인에 의해 제주도 화산암은 두 개의 서로 다른 선형근사로 대표시킬 수 있음을 알 수 있었다. 그리고 P파 속도와 S파 속도와의 관계와 흡수율 및 공극률과 건조 상태의 암석에 대한 일축압축강도와의 각각의 관계에 대하여 흡수율 및 공극률과 겉보기 비중과의 두 개의 서로 다른 선형근사 관계를 고려함으로서, P파 속도와 S파 속도와의 관계와 흡수율 및 공극률과 일축압축강도와의 관계를 명확하게 구분할 수 있음을 알 수 있었다.

• 한국농공학회논문집
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• 제58권1호
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• pp.61-71
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• 2016

This study performed the physical and mechanical experiment on the samples of costal marine clays individually collected in western and southern regions to identify the characteristics of western and southern costal marine clay. Based on the experiment result, the characteristics of costal marine clay is identified undrained shear strength. Based on the experiment result on the physical and mechanical characteristics of costal marine clays, the regression is presented that can analyze the mechanical characteristics of undrained shear strength in costal marine clay of Korea, region of Korea and western-southern region. The correlation of uniaxial compressive strength and undrained shear strength was suitable for use of western-southern region correlation equation. The test result of Jeonnam Yeosu area compares with prediction results of previous researchers formula and western-southern region formula. Prediction results appear highest reliability on the 0.827 of coefficient of determination in the prediction results of the western-southern region formula.

• 한국자동차공학회논문집
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• 제23권2호
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• pp.214-220
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• 2015

Since resources of fossil fuels are limited, development of alternative energies is emphasized and research on new-regenerative energy is actively in progress worldwide. In present research, physical and chemical characteristics of mixed fuel are analyzed in detail for the different mixture rate of conventional and bio-diesel and ultrasonic irradiation time. Experimental setup consists of ultrasonic generator, vibrator, horn, and reflector. Various physical and chemical characteristics of fuel are investigated for volumetric mixture rate of bio-diesel from 0 to 100%. As results, viscosity and surface tension is increased as mixture rate of bio-diesel is increased. Also, molecular splits and reunions are increased and decreased repeatedly after some period of time as ultrasonic energy irradiation time is increased. As conclusion of experiments, Olefin rate, Branch index, and Aromatic rate are influenced by ultrasonic irradiation time.