• Journal of the Korean Wood Science and Technology
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• v.32 no.3
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• pp.15-24
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• 2004

The present work was undertaken to investigate the anatomical and chemical characteristics of transgenic poplar down-regulated with antisense OMT gene. Also the distribution of lignin in transgenic poplar trees was investigated at cellular level. No visible abnormal phenotype was observed in the fibers and vessel elements of transgenic poplar. Any marked differences in the staining intensities of Wiesner and Mäule color reaction were not identified in the transgenic poplar. TEM micrographs did not show any staining intensities in the cell walls stained with KMnO₄. Interestingly, the UV spectroscopy of semi-thin sections exhibited a distinct decrease of lignin absorption at 280 nm in the vessel walls, indicating transgenic poplar wood with lower amount of guaiacyl lignin in vessel elements. Chemical composition of antisense OMT poplar was almost identical to that of wild-type poplar. Klason lignin content of transgenic poplar did not show any significant difference from that of the controls. The solid state NMR spectra revealed the transgenic poplar with only slightly more syringyl lignin than the control. The present work showed that antisense OMT gene constructed in the poplar was not enough to reduce the overall content of Klason lignin, and suggested that the expression of transformation was confined to vessel walls.

• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.2
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• pp.57-69
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• 2022

This study analyzes the fuel conditions and environmental effects of converting heating in rural villages that rely on fossil fuels into wood fuel. In particular, we tried to derive the most important considerations when using wooden chips as fuel in aging agricultural villages where various variables such as weather, facility characteristics, fuel quality, and maintenance capabilities work. Above all, an experiment was conducted by comparing it with oak trees to determine whether Italian poplar, a representative attribute water created to supply fuel wood in Korea, is suitable for heating fuel. Through experiments, 1) Even though the supply of poplar wood chips during 10 hours of operation was 60.74 kg less than that of hardwood chips, the production of hot water was 140 kWh higher. 2) The higher the exhaust gas temperature, the proportional (increase) oxygen concentration and inversely (decrease) PM and CO emissions. 3) Poplar has twice as much ash content as hardwood and three times more fine dust has been detected, but it meets all the standards for wood quality at the Korea Forest Science Institute. 4) Under the condition that there is a difference in water content (7.7%), hardwood cost 1.13 times more wood chips per 1 MWh than poplar, and even if the water content is corrected equally, hardwood cost 1.05 times more per 1 MWh than poplar. 5) In conclusion, it was proved that the fuel possibility, economic possibility, and environmental possibility of poplar wood chips are sufficient.

• Journal of the Korean Wood Science and Technology
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• v.32 no.6
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• pp.7-13
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• 2004

In this study, the Korean pine wood (Pinus densiflora Sieb. et Zucc) and Italian poplar wood (Populus euramericana Guinier) was treated with a mixture of monoammonium phosphate (MAP) and boric acid. Their usability as fire retardant and as decay-resistant construction and interior materials were evaluated by testing of chemicals, corrosion rate and absorption rate, weight loss and chemical contents. An experiment was performed to compare treated pine wood and Italian poplar wood. According to the results, Italian poplar wood had higher specific gravity and retention of chemicals than pine wood, and treated wood showed higher decay-resistance than untreated one. Weight loss was less in treated wood than untreated one because the degree of decay was lower in the former than the latter. Corrosion rate and absorption rate met the KS standard for wood preservative performance. The chemical contents analysis was carried out to determine the degree of decay and it was found that the preservative effect of chemical treatment was lower in Italian poplar wood than in pine wood.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.4
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• pp.16-20
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• 2013

Yellow poplar grown in Korea and imported eucalyptus were compared their kraft pulping characteristics and evaluated the replacing possibility of eucalyptus by yellow poplar. Difference between yellow poplar and eucalyptus were investigated in chemical composition and fiber morphology. Yellow poplar kraft pulp resulted in the higher yield, longer fiber length and thicker fiber, and higher pulp strength than that of eucalyptus. More xylan survived in eucalyptus than yellow poplar during kraft pulping, which led to similar pulp yield even though polysaccharides in Eucalyptus was 4.5% less than in yellow poplar. Longer and thicker yellow poplar pulp fiber resulted in better beating response and pulp strength properties.

• Journal of the Korean Wood Science and Technology
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• v.44 no.2
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• pp.204-217
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• 2016

Modified poplar has emerged as a potential raw material for furniture production. Lack of specific modified poplar strength information; however, restricts applications in the furniture industry especially as related to strength in corner-joints. Optimization of strength in L-shaped corner dowel modified poplar joints under compression loads utilizing finite element analysis (FEA) by Taguchi method with the focus of this study. Four experiment factors (i.e., Structure Style, Tenon Length, Tenon Diameter, and Tenon Gap), each at three levels, were conducted by adopting a $L_9-3^4$ Taguchi orthodoxy array (OA) to determine the optimal combination of factors and levels for the von Mises stress utilizing ANSYS software. Results of Signal-to-Noise ratio (S/N) analysis and the analysis of variance (ANOVA) revealed the optimal L-shaped corner dowel joint in modified poplar is $45^{\circ}$ Bevel Butt in structure style, 24 mm in tenon length, 6 mm in tenon diameter, and 20 mm in tenon gap. Tenon length and tenon gap are determined to be significant design factors for affecting von Mises Stress. Confirmation tests with optimal levels and experimental test indicated the predicted optimal condition is comparable to the actual experimental optimal condition.

• Journal of the Korean Wood Science and Technology
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• v.34 no.6
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• pp.44-50
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• 2006

To characterize thermo-chemical feature of su gar conversion of woody biomass poplar wood (Populus alba${\times}$glandulosa ) by sub- and supercritical water was treated for 60s under subcritical (23 MPa, 325 and $350^{\circ}C$) and supercritical (23 MPa, 380, 400, and $425^{\circ}C$) conditions, respectively. Among degradation products undegraded poplar wood solids existed in aqueous products. As the treatment temperature increased, the degradation of poplar wood was enhanced and reached up to 83.1% at $425^{\circ}C$. The monomeric sugars derived from fibers of poplar wood by sub- and supercritical treatment were analyzed by high performance anionic exchange chromatography (HPAEC). Under the subcritical temperature ranges, xylan, main hemicellulose component in poplar wood, was preferentially degraded to xylose, while cellulose degradation started at the transition zone between sub and supercritical conditions and was remarkably accelerated at the supercritical condition. The highest yield of monomeric sugars amounts to ca. 7.3% based on air dried wood weight (MC 10%) at $425^{\circ}C$.

• Journal of the Korean Wood Science and Technology
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• v.42 no.4
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• pp.357-366
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• 2014

Based on fundamental properties and machining characteristics of Yellow poplar (Liriodendron tulipifera L.), it has well performance on machinability or workability, drying, and fine surface. Additionally, yellow poplar is light weight and has bright color with high performance of bending processing, so it could be used for furniture or artworks materials and wood-based panel materials. Recently, public attention has been focused on indoor air quality, and Ministry of environment drift more tight regulation on indoor air quality for an apartment house and public facility with the times. Construction materials has been assessed emission of volatile organic compounds (VOCs) and formaldehyde according to law (No.10789), so yellow poplar is also needed to assess these emission characteristics. Emission of VOC and aldehyde compounds from dry and green wood condition of yellow poplar were investigated with KS M 1998:2009. Based on results, more than 30 compounds were detected from yellow poplar, and lower NVOC (natural VOC) were emitted than AVOC (Anthropogenic VOC) and OVOC (other VOC). Formaldehyde emission was lower than $5{\mu}g/m^3$ and acetaldehyde, ketone, and propionaldehyde were detected from yellow poplar. From dry yellow poplar, m-Tolualdehyde ($33.6{\mu}g/m^3$) was additionally detected while no detection of propionaldehyde. After drying process, amount of ketone emission increased significantly. The unique smell of yellow poplar may not only come from emission of acetaldehyde and propionaldehyde.

• Journal of the Korean Wood Science and Technology
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• v.40 no.1
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• pp.1-9
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• 2012

Densified fuels from biomass are widely used in North America and Europe as a regenerable and clean bioenergy. In this study, the fuel characteristics and densification characteristics of Japanese larch and Hyunsasi poplar were studied using a piston-type briquetting machine. The effects of pressure, pressure holding time, species, and particle size on briquette characteristics were studied. At room temperature, the highly densified briquettes of Japanese larch and Hyunsasi poplar can be produced at a compression pressure of 110~170 MPa. The produced briquettes have densities between 0.66 and 0.94 g/$cm^3$ after 28 days of storage at room temperature. The optimum pressure holding time was found to be 12 seconds. There is a linear increase in pressure with increase in density. The densities of briquettes from Japanese larch were higher than those of briquettes from Hyunsasi poplar. Also, the coarser particle size resulted in higher densities in briquettes than the finer particle size.

• Journal of the Korean Wood Science and Technology
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• v.39 no.5
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• pp.406-419
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• 2011

This study was carried out to offer basic information on the wood anatomy of domestic yellow-poplar (Liriodendron tulipifera L.), a new plantation species selected by Korea Forest Service as one of the promising hardwood and bioenergy sources of the future, through comparison of stem wood with root wood in the qualitative and quantitative features. In the qualitative anatomical features, growth rings were distinct in stem wood but relatively less distinct in root wood. And stem wood appeared to have pores in radial multiples of 2 to 5, sometimes clusters but root wood to have pores in radial multiples of 2 to 3, rarely clusters. And numbers of bars in scalariform perforation plates were somewhat numerous in vessel elements of root wood than in those of stem wood. Interestingly, on the other hand, more extraneous materials in the wood rays of tap root than in those of lateral root and stem were confirmed in the chemical composition analyses. In the quantitative anatomical features, pore densities were significantly greater but vessel elements were considerably narrower in stem wood than in root wood. Vessel elements and wood fibers of root wood were considerably longer than those of stem wood. Rays were somewhat more numerous in stem wood than in root wood, and only ray heights of stem wood were more or less greater in cell numbers but both ray heights and widths of stem wood were lower in dimension than those of root wood. The anatomical differences between stem wood and root wood were thought to be associated with different growth environments between the stem above ground and the root below ground.

• Journal of Korea Foresty Energy
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• v.24 no.1
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• pp.39-46
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• 2005

In this study, the possibility of sugar conversion of poplar wood(Populus $alba{\times}rglandulosa$) and their degradation features of major wood components were characterized using flow type supercritical water treatment system. The finely ground poplar wood meals were treated for 2min. under subcritical condition$(23MPa,\;275^{\circ}C\;and\;325^{\circ}C)$ and supercritical condition $(23MPa,\;375^{\circ}C\;and\;415^{\circ}C)$. respectively. The degradation products of poplar wood meals appeared brownish colors, including undegraded solids. Increasing the temperature of the system, the degradation rate of poplar wood meals was accelerated and reached up to $94\%\;at\;375^{\circ}C$. The total amount of reducing sugars in degradation products determined by DNS method were gradually lowered when the temperature condition became severe. This indicated that the reducing sugars formed were further degraded to kan derivatives by certain side reaction such as pyrolysis under higher temperature. In order to characterize degradation features of lignin, the degradation products were extracted with ethylacetate and the organic phases were subjected to GC-MS analysis. Main lignin degradation products were identified to vanillin, guaiacol, syrinaldehyde, 4-prophenyl syringol and dihydrosinapyl alcohol, which could be formed by the cleavage of ether linkages in lignin polymers by high temperature condition.