• Journal of the Korean Wood Science and Technology
• /
• v.25 no.3
• /
• pp.8-15
• /
• 1997

The ultrasonic velocity and dynamic MOE of acetylated bamboos were investigated using PUNDIT, a transit time measuring device for longitudinal ultrasonic propagation. Bamboo specimens were boiled in acetic anhydride for 2, 4 and 6 hours, and the maximum average WPG (Weight Percentage Gain) of 19% was obtained at 6 hours. The volumes of acetylated bamboos increase with boiling time and WPG, while as WPG increases their oven-dry densities generally increase with a concave around 5% WPG. This oven-dry density pattern likely influences the trends of ultrasonic velocity and dynamic MOE. which generally decrease with a convex around 5% WPG. It is postulated that during boiling extractives in a bamboo move and aggregate at its surfaces transiently, resulting in the increase of ultrasonic velocity and dynamic MOE. To explain the fact that ultrasonic velocity varies with WPG a simple model was proposed and some ultrasonic properties of a transmitted wave were examined.

• Physical Therapy Korea
• /
• v.29 no.3
• /
• pp.241-248
• /
• 2022

Background: The PyeongChang 2018 Winter Paralympic Games (WPG) being one of the most successful Paralympic Games (PG) in modern athletic world history, hosted the largest number of elite athletes representing 49 National Paralympic Committees (NPCs). Objects: The present investigation highlighted the demographic and clinical characteristics of injured athletes and non-athletes and the physiotherapy services provided during the PyeongChang 2018 WPG. Methods: Prospective descriptive epidemiology study, in which the study group comprised of 201 participants (51 athletes and 150 non-athletes) who were admitted to and utilized the polyclinic physiotherapy service of 2018 PyeongChang WPG in Physiotherapy Department of Paralympic Village from March 1, 2018 to March 20, 2018. Results: Qualitative frequency analysis of injury type demonstrated highest number of chronic injuries (51%, n = 100) in athletes and non-athletes. Anatomical injury site analysis revealed that the spine and shoulder areas were affected with equal frequency for athletes (54.9%, n = 14), whereas for non-athletes, the frequencies of spine and shoulder area injuries were 36.7% (n = 55) and 26% (n = 39), respectively. The Pyeongchang WPG showed a high rate of athletes visiting the physiotherapy service during the pre-competition period (33.3%, n = 50), which may have led to smaller incidence rate of traumatic injury. The physiotherapy treatment service analysis demonstrated that manual therapy (35.4%, n = 230) was most commonly utilized, followed by transcutaneous electrical nerve stimulation/interference current therapy (TENS/ICT), therapeutic massage and therapeutic exercise. Conclusion: We established the importance of prophylactic and preventive physiotherapy services to reduce the risk of sports injuries during WPG.

• Journal of the Korea Furniture Society
• /
• v.11 no.2
• /
• pp.79-84
• /
• 2000

It is well-known fact that dimensional stability of wood is greatly enhanced by acetylation of wood. This dimensional stability results from bulking of the reacted acetate within the cell wall, which reduces further swelling when the modified woods come into contact with water or water vapor. The purpose of this research was to determine the water absorption and dimensional stability of the acetylated solid wood in liquid water and in humidity tests. Beech and red oak were acetylated. Moisture and water absorption of acetylated wood were quite dependent on weight percent gain(WPG). Antiswelling efficiency(ASE) was quite dependent on WPG, but was not dependent on species.

• Journal of Korea Foresty Energy
• /
• v.20 no.2
• /
• pp.41-45
• /
• 2001

Japanese Larch(Larix kaempferi) was treated with aqueous solutions(30%, 40%, 50%) of polyethylene glycols(PEG, #1000, #1500, #4000, #6000) for the dimensional stabilization. The antiswelling efficiency(ASE) was measured for the evaluation of the dimensional stabilization. The weight percent gains(WPGs) of the woods treated with 40% solutions were higher than those of the others, and the highest WPG was achieved by treatment with 40% solution of PEG #1500. The ASE decreased with increasing molecular weight of PEG. ASE of woods treated with PEG #1000 and PEG #1500 were higher than those of the others.

• Proceedings of the Korean Institute of Industrial Safety Conference
• /
• 1999.06a
• /
• pp.201-206
• /
• 1999

The influence of surface preparation methods after plasma cutting on the quality of welding zone is investigated. For comparison. three types of welded specimens are prepared by machining(YM), plasma cutting with light regrinding(WPG) and without regrinding(WP), by using three kinds of materials, carbon steel(S45C), stainless steel(Type304) and aluminum alloy (6061-T6). Nondestructive examination, hardness test, microstructure examination, and fracture toughness test are performed. The results show that there is no appreciable reduction in hardness or fracture toughness in WP specimens. But a little difference in heat affected gone size is observed.

• Journal of the Korean Wood Science and Technology
• /
• v.28 no.1
• /
• pp.36-41
• /
• 2000

This study was carried out to introduce functional groups onto wood by reacting with 2-methacryloyloxyethyl isocyanate(MOI). The effects of the catalyst and the reaction conditions(temperature and time) on the treatment were investigated. The evidence of bonding between wood and MOI were examined by infrared(IR) spectroscopy. The change in surface characteristics of MOI treated wood was examined by water contact angle measurement and X-ray photoelectron spectroscopy(XPS). Wood reacted quickly with MOI in the presence of di-n-butiltin dilaurate catalyst. Especially, the increase in weight percent gain(WPG) with increasing in reaction time was remarkable at the reaction temperature of over $50^{\circ}C$. The IR spectrum of wood reacted with MOI showed a strong urethane absorption(1715 $cm^{-1}$) but no isocyanate(2235 $cm^{-1}$) absorption. It also showed a sharp olefinic C=C double bond absorption at 1635 $cm^{-1}$. This means that an introduced methacrylate group becomes the starting point of further graft copolymerization with another vinyl monomers. The wood modified with MOI showed a gradual increase in contact angle with increasing in WPG, which means that the hydrophilic wood surface become quite hydrophobic. Also, it was cleared that most parts of the wood surface were modified with MOI by XPS analysis.

• Journal of the Korean Wood Science and Technology
• /
• v.51 no.6
• /
• pp.542-554
• /
• 2023

This study is a continuation of our previous work, which focused on the resistance of jabon wood to termites after impregnation with wood vinegar (WV) and animal-based adhesive (kak). This paper presents the physicomechanical properties of fast-growing jabon wood impregnated with kak at two concentrations (8% and 10%) in wood vinegar or water as a solvent with and without 4% borax. The physical properties of the impregnation solution, that is, viscosity, density, pH, and solid content, were evaluated according to SNI 06-4567-1998. Some physical parameters, such as weight percent gain (WPG), density, water uptake, anti-swelling efficiency (ASE), crystallinity, and mechanical properties, i.e., modulus of elasticity (MOE), modulus of rupture (MOR), and compression strength parallel to the grain (CS), of the impregnated wood were determined. Based on these results, wood impregnated using a mixture of kak in WV presented better physical (increased WPG, density, dimensional stability, and crystallinity) and mechanical (increased MOE/MOR and compression strength) properties than wood impregnated with a water solvent or untreated wood. The wood impregnated using WV and water solvent improved the physical and mechanical properties. The density of the wood increased by 44%-58% and 32%-47%, ASE radial-tangential increased by 38%-45%; 15%-28% after 24 h of water immersion, crystallinity increased by 59%-74%; 36%, MOE increased by 46%-57%; 28%-31%, MOR increased by 29%-34%; 14%-27%, and compression strength increased by 40%-76%; 38%-72% values to untreated wood.

• Journal of the Korea Furniture Society
• /
• v.19 no.1
• /
• pp.83-90
• /
• 2008

Gypsum-wood composites were made by introducing inorganic substances into wood using calcium chloride, first treating solution, and sodium sulfate, secondary treating solution, by double diffusion process under atmospheric pressure at room temperature. The process conducted as follows: water saturated specimens were soaked in calcium chloride solutions at several concentration. Then the specimens were soaked further in saturated sodium sulfate solution, and they were leached in flowing tap water for 24h. To attain sufficient weight percent gain (WPG) values, the suitable concentration of calcium chloride and soaking time in saturated sodium sulfate solution were 20% and 48h, respectively. Inorganic substances were produced mainly in the lumina of tracheides. It was made sure that these substances were dihydrate gypsum($CaSO_4$ $2H_2O$) by X -ray microanalysis (SEM-EDX). The composites had good fire resistance due to low heat transfer rate of gypsum formed in wood. However, the composites had little decay resistances, because they showed high weight losses by test fungi attacks.

• Journal of the Korean Wood Science and Technology
• /
• v.24 no.4
• /
• pp.40-46
• /
• 1996

It is well-known fact that dimensional stability of wood is greatly enhanced by acetylation of wood. This dimensional stability results from bulking of the reacted acetate within the cell wall, which reduces further swelling when the modified woods corne into contact with water or water vapor. The purpose of this research was to determine the water absorption and dimensional stability of the acetylated solid wood in liquid water and in humidity tests. Radiata pine, Siberian larch, and Japanese larch were acetylated. Antiswelling efficiency(ASE) and equilibrium moisture content(EMC) of acetylated wood, at 95% RH and $20^{\circ}C$ after 4weeks, was quite dependent on WPG, but was not dependent on species.

• Journal of KIISE:Databases
• /
• v.28 no.2
• /
• pp.233-243
• /
• 2001

XML은 Web에서 운영되는 모든 데이터 표현에 대한 표준이다. 여러 웹 소스들로부터 이질적인 데이터를 XML 데이터로 통합할 수 있다. 많은 연구자들이 XML처리에 대한 연구를 해 왔다. 이러한 연구의 집합체로서, 우리는 XML 데이터의 효율적인 저장, 추출, 질의, 웹 환경에서의 응용을 위한 기반 시스템인 XWEET를 제안, 구현하였다. XWEET는 XML 데이터의 표현을 위해 XDM이라는 데이터 모델을 사용하였으며, XML 데이터의 저장을 위해 PDM을, 이질적인 정보 소스로부터의 데이터 통합을 위해 Wrapper와 XWS를, 서로 다른 XML 문서 형식의 통합된 표현을 위해 XSI를 제공한다. 이렇게 통합, 저장된 데이터는 XML/QL 형식의 질의를 통해 접근되며, XQP는 제공되는 질의를 처리한다. 또한, 사용자들은 웹 환경에서 수행괴는 응용을 작성할 수 있는 기반을 제공받는다. WPG와 HTML/XML Template는 웹 응용의 수행 결과를 정의된 HTML이나 XML로 생성하도록 해 주며, WebTP는 웹기반 워크플로우를 위한 기반 기능을 제공한다.