• Journal of the Korean Wood Science and Technology
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• 제39권2호
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• pp.172-178
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• 2011

Three different finger-jointed lumbers which have different geometric features and adhesives were manufactured and studied in this study. Larch and pitch pine lumbers with and without preservative treatment were used. Bending MOE was measured as the preliminary investigation for grouping the specimen. After the finger, bending MOE of two wood species without preservative treatment shows over 97% property of the control group. The tensile modulus also shows almost same property after the finger joint. And it is found out that the preservative treatment induce little effect on bending and tensile MOE. Based on this result, high performance of examined finger-jointed lumber can be found out. However, tensile strength decreased around 20% which would be induced by the crack along the root of the finger which is formed near the edge during manufacturing stage. And finger-jointed lumber with preservative treatment even shows higher decrement of the tensile strength with higher wooden part failure mode.

• 한국가구학회지
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• 제22권3호
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• pp.239-243
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• 2011

In this study, the coating properties and surface performance of exotic cherry wood (Prunus serotina) were estimated, reviewing color difference, hardness and abrasion resistibility in order to evaluate probability as construction interior members such as wall and floor. The reduction effect of color difference was represented in the order of water soluble color stain, water soluble transparent stain, and non-coated lumber. However, the tendency of distinct difference according to wood grain pattern was not found. The wavy grain lumber showed better properties in hardness and resistance to abrasion than quarter grain. In conclusion, it was supposed that the application of wavy grain lumber in wall and floor as interior materials would be acceptable in practicality.

• 한국산림과학회지
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• 제96권2호
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• pp.197-202
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• 2007

This study is conducted to investigate the factors affecting lumber conversion rate of sawmill industry in South Korea. Data were obtained from the survey of 38 sawmills in all geographic regions of South Korea. The variables examined in this study were region, softwood/hardwood log, domestic/imported/both log, the number of power-driven carriages (PDC) installed, the year when and country where PDCs was manufactured, the horse power of PDC, the number of labors required to operate each PDC, the sawing capacity of mill (mill size), and the types of major product and by-products. The lumber recovery factor (LRF) of sawmills were significantly influenced by the origin of logs, level of PDC automation, sawmill size, and size of logs (measured in diameter and length) while not by the location of the mill, types of major product and by-product, log species, and characteristics of PDC. Although these results provide useful information for understanding the technological characteristics of the Korean sawmill industry, further investigation with larger sample is necessary to reveal the more reliable characteristics of sawmill industry in South Korea.

• 대한한의진단학회지
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• 제17권3호
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• pp.253-262
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• 2013

Objectives This study is on the quantifying method for the acupuncture-moxa cautery heat response index, which are based on the some definitions. Methods The magnitude of the acupuncture-moxa cautery is defined by the pain-feeling of the acupuncture-moxa cautery stimulation: the stimulation magnitude of the acupuncture is 1, that of the direct moxa-cautery is 2, and that of the indirect moxa-cautery is 0.5. The heat variation of the acupuncture-moxa cautery stimulation is defined by the heat variations of the characteristic points pre/post-stimulations in the stenosis of the lumber. The acupuncture-moxa cautery heat response index is defined by the ratio of between the magnitude of the heat variation and the natural logarithmic magnitude of the stimulation. Results With the respect of the acupuncture-moxa cautery heat response index, I experimented and estimated 4 types of stimulations in the stenosis of the lumber: the single acupuncture stimulation with 40%, the single direct moxa-cautery stimulation with 52%, the combinational acupuncture-moxa cautery stimulations with 27%, and the combinational acupuncture-indirect electronic moxa-cautery stimulations with 53%. Conclusions According to the acupuncture-moxa cautery heat response index. the combinational acupuncture-moxa cautery stimulations especially need to be changed to the combinational acupuncture-indirect electronic moxa-cautery stimulations.

• 임산에너지
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• 제20권1호
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• pp.73-80
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• 2001

본 연구에서는 국산 소경제(소나무, 낙엽송)로 제작한 집성 아치재의 강도와 제작방법을 연구하였다. 아치형 집성재는 강도와 초기강성을 향상시키기 위하여 여러 가지 다른 kal나의 조합으로 제작하여 강도를 평가하였다. 실험결과 낙엽송 집성재의 rkde가 소나무 집성재보다 높게 나타났으며, 7ply 집성재의 최대하중이 5ply보다 약 2배 높은 경향을 보였다. 또한, 핑거 조인트된 라미나로 제작된 집성재는 무종접합 집성재보다 약 15.8% 낮은 강도를 나타내었다. 이 같은 문제해결의 한 방안으로 집성재의 최외각층에 베니어를 적층시켜 보강하였을 때, 베니어 집성재가 베니어로 보강하지 않은 집성재보다 월등히 높은 강도를 나타내었다. 본 연구결과 알맞은 라미나 조합으로 부재를 제작한다면 소경재의 활용이 가는하고 부가가치를 높일 수 있을 것으로 생각된다.

• Journal of the Korean Wood Science and Technology
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• 제46권1호
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• pp.93-99
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• 2018

국내산 낙엽송 소경각재의 휨 강도 성능을 예측하기 위하여 비파괴적인 지표의 검토가 필요하다. 본 연구에서는 낙엽송 소경각재(단면 $89{\times}120mm$)를 초음파법, 종진동법, 소하중법의 비파괴 방법으로 탄성계수를 측정하였다. 실측 탄성계수와 유의성이 높은 비파괴 측정 방법을 결정 후 휨 파괴계수 예측 지표로 적용하였다. 종진동법으로 측정된 탄성계수가 실측 탄성계수와 가장 높은 유의성을 나타냈다. 휨 파괴계수와 실측 탄성계수의 유의성도 매우 밀접하게 측정되었으므로 종진동법에 의한 비파괴 탄성계수로 소경각재의 휨 파괴계수를 예측하였다.

• 임산에너지
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• 제25권2호
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• pp.49-54
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• 2006

국산 침엽수재의 구조재 활용에 필요한 등급구분을 위해 소나무, 잣나무와 낙엽송 $2{\times}6"$ 부재에 대해 초음파를 이용한 비파괴 방법을 적용하였다. 정적 탄성계수와 초음파 시험에 의한 동적 탄성계수의 상관관계를 나타내는 k-factor는 소나무의 경우 1.0602, 잣나무 1.0013, 낙엽송 1.2320로 나타났다. k-factor를 적용할 경우 비파괴방법에 의한 동적 탄성계수 측정에 의해 침엽수 구조부재 등급구분이 가능할 것으로 판단되었다. 기계응력 등급구분에서 소나무는 E9 이상의 등급이 전체의 76%인 반면 잣나무는 E7 이상의 등급이 전체의 85%, 낙엽송은 E11 이상의 등급이 68% 분포하였다. 정적 탄성계수와 휨파괴계수(MOR)의 상관관계도 비교적 높게 나타나 이를 동적 탄성계수로부터 추정한 k-factor와 연계할 경우 초음파 비파괴 등급구분 방법에 의해 국산 침엽수재의 휨강도 성능평가가 가능할 것으로 판단되었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.879-880
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• 2008

Music can give pleasure to people according to a rhythm, and Musical instrument can make various sounds according to quality of the lumber. A string instrument makes sound by strings so it feels very soft and a brass makes to feel a high pitched tone. A gayageum makes sound by oscillation which is transferred to a resonator when a string is touched. And this sound is very soft and faint. Therefore, in this paper, we researched sound properties of gayageum according to quality of the lumber of musical instrument. As the result of researches, we found that melody is affected by the annual ring of the resonance lumber.

• Journal of the Korean Wood Science and Technology
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• 제39권5호
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• pp.381-389
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• 2011

The effect of organoclays on the mechanical properties of cured phenol formaldehyde resin and oriented strand lumber made from Mountain Pine Beetle killed pine strands was analyzed. Three organoclays were used: a natural montmorillonite, hydrophobic organically modified 10 A, and hydrophilic organically modified 30 B. The oriented strand lumber samples were less creep deformation as well as improved internal bonding strength by adding organoclays in the order of 10 A 2% > MMT 2% > 30 B 2% > control. Furthermore, time-temperature superposition (TTS) analysis was proved to be able to predict the long-term creep behavior of MPB-OSL samples.

• Journal of the Korean Wood Science and Technology
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• 제27권1호
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• pp.50-55
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• 1999

Since ultrasonic stress wave velocity varies with wood temperature and moisture content, ultrasonic stress wave could be a tool to predict wood moisture content if temperature effect could be eliminated. This temperature effect was investigated by measuring the velocities of ultrasonic stress waves transmitting through air, a metal bar and a dimension lumber at various temperatures. For air the velocity and amplitude of the ultrasonic stress wave increase with temperature, while for a metal bar and a dimension lumber those decrease as temperature increases. However all three materials showed velocity hystereses with a temperature cycle. The effect of temperature and moisture content on stress wave velocity of a dimension lumber was depicted in the form of a three dimensional graph. The plot of stress wave velocity vs. wood moisture content was well fitted by two regression equations: a exponential equation below 46% and a linear equation above 46%.