• Applied Chemistry for Engineering
• /
• v.33 no.4
• /
• pp.373-380
• /
• 2022

In this study, Chung's equations 1, 2, and 3 were extended to standardize smoke safety rating evaluation in case of fire, and Chung's equations-V, smoke performance index-V, and smoke growth index-V were calculated. Five types of wood were selected and their smoke indices were measured using the cone calorimeter method according to ISO 5660-1. The smoke risk was graded by the smoke risk index-VI according to Chung's equation-VI. Smoke risk index-VI increased in the order of PMMA (1) ≈ maple (1.01) < ash (1.57) < needle fir (4.98) < paulownia (46.15) < western red cedar (106.26). It was predicted that maple and ash had the lowest smoke risk, and paulownia and western red cedar had the highest. The five samples' CO mean production rate (COP_mean) was 0.0009~0.0024 g/s, indicating that these woods were incompletely burned than the polymethyl methacrylate (PMMA) reference material. Regarding the smoke properties of the chosen woods, the smoke performance index-V (SPI-V) increased as the bulk density increased, and the smoke risk index-VI (SRI-VI) decreased.

• Journal of Korea Entertainment Industry Association
• /
• v.13 no.8
• /
• pp.291-302
• /
• 2019

In this paper, we first looked at the structures and characteristics of the musical instrument to study the tone of haegeum, which is the only Korean musical instrument made using all the eight ingredients that make gugak instruments, and which is now the most frequently used in fusion gugak or pop music production sites. In addition, for the comparison of the various tones of the haegeum, under the same conditions, we analized how the haegeum's tone changes according to the types of Wonsan, which works as the bridge of the haegeum. Four Wonsan made of Park, Rosewood, Maple and Black Dan were used in the experiment, and low, medium, and high notes were recorded to compare the inner and outter open strings and the sound ranges. By doing so, we looked at the composition of frequency characteristics and the distribution and analyzed the timbres according to the types of Wonsan. Based on this study, it is expected to help the performers in the field choose the proper Wonsan according to each harmony part, rather than just to their tastes when performing Gugak orchestral music or haegeum ensemble. We also look forward to playing haegeum and using the timbres in various combinations of Wonsan that suit the genres at the pop music industry.

• Korean journal of applied entomology
• /
• v.15 no.1 s.26
• /
• pp.17-21
• /
• 1976

Four species of the genus Xiphinema have been identified, three of which are new to Korea. X. radicicola which is distributed geographically from the north (Suweon) to the south (Jeiu) of the country is found from soil around roots of apple and elm tree. X. bakeri is a confirmed species to the specimens collected from mulberry grove at Suweon. X. pini was collected from soil around roots of broad leaf lilac and maple trees at Mt. Kyeryongsan. Some notes of Korean populations of X. americanum are given.

• International Journal of Aeronautical and Space Sciences
• /
• v.13 no.3
• /
• pp.317-322
• /
• 2012

The low speed aerodynamic characteristics for a modified sonic arc airfoil which is designed by using the nose shape function of sonic arc, the shape function of NACA four-digit wing sections, and Maple are experimentally investigated. The small rotor blades of a modified sonic arc and NACA0012 airfoil are precisely fabricated with a commercially available light aluminum(Al 6061-T6) and are spin tested over a low speed range (3000rpm-5000rpm). In a consuming power comparison, the consuming powers of NACA0012 are higher than that of modified sonic arcs at each pitch angle. The measured rotor thrust for each pitch angle is used to estimate the rotor thrust coefficient according to momentum theory in the hover state. The value of thrust coefficients for both two airfoils at each pitch angle show almost constant values over the low Mach number range. However, the rotor thrust coefficient of NACA0012 is higher than that of the modified sonic arc at each pitch angle. In conclusion, the aerodynamic performance of NACA0012 is better than that of modified sonic arcs in the low speed regime. This test model will provide a convenient platform for improving the aerodynamic performance of small scale airfoils and for performing design optimization studies.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.26 no.4
• /
• pp.257-263
• /
• 2013

In this paper, Solar, Wind, fuel cell used in a Power conversion devices and industrial inverter motor to increase the efficiency of energy consumption, which is a core part of high-efficiency, high-voltage Trench Gate Field Stop IGBT was studied. For this purpose Planar type NPT IGBT and Planar type Field Stop IGBT have designed a basic structure designed to Trench Gate Field Stop IGBT based on the completed structure by analyzing the energy consumption of electrical characteristics, efficiency is a key part, high-efficiency and high-voltage inverter for industry regarding the optimization design for Trench Gate Field Stop IGBT.

• Journal of the Korea Furniture Society
• /
• v.18 no.2
• /
• pp.143-146
• /
• 2007

This study was carried out to assess the dimensional stability of wood material treated by plastic processing for bentwood and compression wood. The evaluation method was different between two wood materials, but the treatments for them were very similar to each other. One of the main methods is heat treatment with sufficient water vapor. In bentwood, the used species were painted maple (Acer mono), bitter wood (Picrasma quassioides) and birch (Betula schmidtii). Steaming was the worst treatment method for dimensional stabilization of bentwood. The best results could be attained with PEG treatment for dimensional stabilization of bentwood. Dimensional stability of bitter wood was found to be conspicuous. However the steaming treatment at lower temperatures, i.e., about $130^{\circ}C$ was not suitable for dimensional stability of bentwood. In compression wood, the used specimen was Italian poplar wood (Populus euramericana). Two heat compressive pressing conditions, an open-press system and an air-tighten closed-press system, were used. The recovery rate was measured after boiling and/or absorbing in water to estimate the dimensional stability of heat compressed wood. The best dimensional stability of compressed wood in the air-tighten closed-press system was found to be better at $200^{\circ}C$ than $180^{\circ}C$. The best compression rate for dimensional stability was 73 percent.

• Journal of Environmental Health Sciences
• /
• v.39 no.6
• /
• pp.483-491
• /
• 2013

Objectives: Electronic cigarettes are battery powered devices that convert a nicotine-containing liquid into an inhalable vapor. The device aerosolizes nicotine so that it is readily entrained into the respiratory tract, from where it enters the bloodstream. Information on the safety of E-cigarettes is required. Methods: Seventeen articles on studies analyzing toxic substances in the liquid and gas phases of electronic cigarettes were reviewed. Results: Tobacco-specific nitrosamines, bis(2-ethylhexyl) phthalate, formaldehyde and acetaldehyde, known to be carcinogenic agents in humans or animals, were detected in the liquid and gas phases. In addition, diethyl phthalate, acetone, ethanol, cresol, xylene, propylene, styrene, triethylene glycol, tetraethylene glycol, pentaethylene glycol cis-3-hexen-1-ol, methyl cinnamate and undecane were identified in the liquid and gas phases of E-cigarettes. Propylene glycol, glycerin, 1-methoxy-2-propanol, 1-hydroxy-2- propanone, acetic acid, 1-menthone, 2,3-butanediol, menthol, carvone, maple lactone, benzyl alcohol, 2-methyl-2-pentanoic acid, ethyl mantel, ethyl cinnamate, myosamine, benzoic acid, 2,3-bipyridine, cotinine, hexadecanoic acid, and 1'1-oxybis-2-propanol were detected in the vapors of E-cigarettes. Conclusion: The hazardous compounds identified in the liquid and gas phases of E-cigarettes should be controlled for the lowest concentrations in the raw materials and production procedures.

• The Journal of the Acoustical Society of Korea
• /
• v.24 no.6
• /
• pp.334-342
• /
• 2005

In this Paper. a time-domain geoacoustic inversion was performed using the bulb signals measured during MがU. 04 experiment conducted in the East Sea of Korea in 2004. An obiective function was defined as a direct cross-correlation between the measured and the simulated signals in time domain. The ray theory was used to model the wave propagation in time domain and optimizations were Performed using VFSA (very fast simulated annealing) algorithm. Comparison of inversion results with those from transmission loss matching (an accompanying paper in this issue of the Journal of the Acoustical Society of Korea) shows that Parameters are consistently inverted. Direct time series comparisons between the measured signals and the simulated signals are Presented based on inversion results.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2011.05a
• /
• pp.215-215
• /
• 2011

우리나라 하천의 대부분은 산지에서 발원하며 전 국토의 약 67%가 산지하천 유역에 포함된다. 최근 기후변화로 인해 여름철 집중호우가 증가하고 있는 상황에서 강우의 예측이 어렵고 경사가 급한 산지하천 유역의 피해가 가중되고 있으며 돌발홍수나 산사태와 같은 산지재해 예방을 위한 대책 마련이 시급히 요구되고 있다. 산지하천유역에서 발생하는 재해를 예방하고 피해를 저감하기 위해서는 재해위험지역에 대한 선정 및 상시 모니터링 체계의 구축이 필요하며 본 연구에서는 격자기반의 산지하천 모니터링 시스템을 구축하여 강우상황과 예측정보, 이동상황을 모니터링 할 수 있는 시스템을 구축하였다. 산지하천 모니터링 시스템은 기상청 레이더 강우를 활용한 실시간 강우자료 및 강우예측자료(MAPLE) 표출, 분포형 수문모형과 연계한 유출분석 결과의 제공, AWS를 이용한 지점강우량 표출 등으로 구성된다. 또한, 지점자료 혹은 격자자료로 이원화되어 있는 기존 하천유역 모니터링 체계를 통합하여 사용자가 원하는 유역에 대한 기상자료의 모니터링과 위험지역에 설치된 지점관측정보를 연계 운영할 수 있도록 구현된 특징이 있다. 본 시스템은 현재 강원도 인제 내린천 유역을 대상으로 시험운영 중이며 격자기반의 강우모니터링과 토석류 현장모니터링 결과를 연계한 위험지 관리에 활용되고 있다.

• Journal of the Korea Furniture Society
• /
• v.13 no.1
• /
• pp.71-83
• /
• 2002

This study was carried out to develop colored-wood furniture using veneer, small-round log and fiberboard to protect forest resources through the study of minimalism. which advocates the environmental issue inherent to contemporary furniture in the postmodern era. Based on the historical and theoretical context of minimalism closely related to the environmental protection, this study suggested the technical way how to produce the environment-friendly furniture with the least use of valuable and natural log. Finally, the color-wooden furniture was developed based on the asceticism, simplification, and repetition of the minimalism in a trend of contemporary furniture design. By soaking a veneer, Psuedotsuga menziesii and small-round log, Pinus densiflora into a very-diluted organic dye, the environment-friendly and colored-wood furniture could be created in harmony with contemporary interior space, which has showed various colors such as yellow, blue, red, and green with a pastel tone. The spring wood of the colored softwood was deeply stained, while the summer wood was lightly done. By utilizing such valueless used woods which have been little in furniture production, it was possible to decrease the consumption of precious raw log such as zelkova, ebony, rose, maple, cherry, mahogany and so on. Thus, it became obvious to be able for contemporary furniture designers to produce beautiful furniture with dyed fiberboard and small-round logs pregnant with minimalism.