• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.5
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• pp.1-7
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• 2012

Chemical composition, morphological properties and papermaking properties of Sasa quelpaertensis Nakai were investigated in order to use it comprehensively. The lignin contents of stalks and leaves were 18.8% and 15.3% and the holocellulose contents were 63.3% and 48.6% respectively. The contents of ash and the amount of water extract showed the higher value than those of wood or other bamboo species. The average fibers length and width of Sasa quelpaertensis Nakai were 780 ${\mu}m$ and 14.8 ${\mu}m$. The fibers of Sasa quelpaertensis Nakai stalk had thinner width and more slender structure than those of softwood. The handsheet made of Sasa quelpaertensis Nakai alkaline pulp showed higher in tensile strength and bulkier structure than those of handsheet made of soft wood unbleached kraft pulp.

• Journal of Korean Society of Forest Science
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• v.96 no.2
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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.

• Journal of the Korean Wood Science and Technology
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• v.33 no.3 s.131
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• pp.64-71
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• 2005

In this study, we attempted to apply ultrasonic treatment for the preservative treatment of two softwood species, Korean pine and Japanese red pines to evaluate its effectiveness. Wood samples were submerged in oilborne preservative, copper naphthenate (NCU) and waterborne preservative, alkyl ammonium compound (AAC) and then treated with ultrasonic wave of 40 kHz, 400 W. After the treatment, the retention and penetration depth of these preservatives in the specimens were measured as a function of treatment time. Both the retention and penetration depth were continuously increased with increasing the treatment time up to 120 hours, where the retention reached about 95% by the application of AAC and the penetrating depth of 95% and 83% by the application of NCU, respectively for both species. The results of electronic microscopic observation showed that the improved retention capacity could be attributed to air deflation, wood extractive deflation working of ultrasonic wavelength, and destruction of wood pits which served as the pathway of preservatives. The results suggested that the use of ultrasonic treatment could be applied to thick wood veneers for the production of laminated wood products.

• Journal of the Korean Wood Science and Technology
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• v.39 no.4
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• pp.281-290
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• 2011

We analyzed the basic characteristics and adsorption property of carbonized materials from thinning byproducts of major Korean wood species for evaluating as charcoal making raw material. Yield of charcoal was decreased with increasing the carbonization temperature for all wood species. Refining degrees was 9.0 at $400^{\circ}C$, 3.3~5.0 at $600^{\circ}C$ and 0 at $800^{\circ}C$, and was no difference among wood species. With increasing the carbonization temperature, the fixed carbon content was also increased, and charcoal from softwoods had more fixed carbon content than that from hardwoods. Specific surface area was increased with increasing the carbonization temperature, softwood charcoal had more specific surface area than that of hardwood. Pinus rigida showed the highest specific surface area. In formaldehyde removal by charcoal, some materials had highest at $600^{\circ}C$ and the others had highest at $800^{\circ}C$. Pinus koraiensis, Qurcus acutissima and MDF showed maximum formaldehyde removal ability at $600^{\circ}C$. Ethylene gas removal ability of charcoal was increased with increasing the carbonization temperature, and the charcoal from Pinus rigida and Robinia pseudoacacia had higher ethylene gas removal ability than the other species.

• Journal of Korean Society of Forest Science
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• v.71 no.1
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• pp.14-21
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• 1985

This study was carried out in order to prevent the devaluation of wood itself and wood products causing by anisotropy, hygroscopicity, shrinkage and swelling - properties that wood itself only have, in order to improve utility of wood, by emphasizing the natural beautiful figures of wood, to develop the dimensional stabilization techniques of wood with PEG that it is a cheap, non-toxic and the impregnation treatment is not difficult, on the effects of PEG molecular weights (200, 400, 600, 1000, 1500, 2000, 4000, 6000) and species (Pinus densiflora S. et Z., Larix leptolepis Gordon., Cryptomeria japonica D. Don., Cornus controversa Hemsl., Quercus variabilis Blume., Prunus sargentii Rehder.). The results were as follows; 1) PEG loading showed the maximum value (137.22%, Pinus densiflora, in PEG 400), the others showed that relatively slow decrease. The lower specific gravity, the more polymer loading. 2) Bulking coefficient didn't particularly show the correlation with specific gravity, for the most part, indicated the maximum values in PEG 600, except that the bulking coefficient of Quercus variabilis distributed between the range of 12-18% in PEG 400-2000. In general, the bulking coefficient of hardwood was higher than that of softwood. 3) Although there was more or less an exception according to species, volumetric swelling reduction was the greatest in PEG 400. That is, its value of Cryptomeria japonica was the greatest value with 95.0%, the others indicated more than 80% except for Prunus sargentii, while volumetric swelling reduction was decreased less than 70% as the molecular weight increase more than 1000. 4) The relative effectiveness of hardwood with high specific gravity was outstandingly higher than softwood. In general, the relative effectiveness of low molecular weight PEG was superior to those of high molecular weight PEG except that Quercus variabilis showed more than 1.6 to the total molecular weight range, while it was no significant difference as the molecular weight increase more than 4000. 5) According to the analysis of the results mentioned above, the dimensional stabilization of hardwood was more effective than softwood. Although volumetric swelling reduction was the greatest at a molecular weight of 400. In the view of polymer loading, bulking coefficiency reduction of swelling and relative effectiveness, it is desirable to use the mixture of PEG of molecular weight in the range of 200-1500. To practical use, it is recommended to study about the effects on the mixed ratio on the bulking coefficient, reduction of swelling and relative effectiveness.

• Journal of the Korea Institute of Building Construction
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• v.11 no.2
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• pp.162-170
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• 2011

As the result of implementing a treated material test and durability test after quickly drying S.P.F. species, a type of softwood structural material, within a short period time, soaking it in liquid phosphate flame proof agent for an hour, microwave heating it, and compressing it from 3.8cm to 1cm, when setting the appropriate heating time of microwave heating at 7 minutes at 5kW, it is observed that it satisfies the target water content (4~5%). It is shown that in a water content measurement of the wood that is compressed after being softened by soaking in the flame proof agent, drying and heating at 3kW for 9 minutes, all specimens satisfied 12~14%, the appropriate water content for exterior wood. Also, it is shown that in terms of the flame performance obtained through a flame resistance treatment of the compressed wood and a treated material test, the specimen soaked in flame proof agent for 30 minutes was the most excellent, and that the performance test result of the compressed wood in all areas, such as nail withdrawal resistance, compression, bending strength, and shearing strength, were all improved in their mechanical features to twice to three times better performances.

• Journal of the Korean Wood Science and Technology
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• v.39 no.6
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• pp.521-530
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• 2011

Nowadays, market demand of structural Glulam is growing and diversifying. The durability of Glulam should be significantly considered when they are intended to apply for out-door use such as timber bridge and pergola. This study was aimed to develop the manufacturing process of preservative treated structural Glulam using domestic softwood species. 10 m long structural Glulam were manufactured from domestic pitch pine logs with CuAz-3 preservative treatment. At each manufacturing process, the production yield was evaluated. Finally, bending tests were performed to verify the structural performance of manufactured Glulam. From the results, it was shown that the preservative treatment process hardly influenced on the production yield. But domestic pitch pine was proved to not be suitable for making the preservative treated Glulam due to the large difference of preservative permeability between sapwood and heartwood.

• Journal of the Korean Wood Science and Technology
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• v.29 no.3
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• pp.1-13
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• 2001

Compression, lateral, and opposite woods in the stem and branch of rimu (Dacrydium cupressinum Lamb.), a softwood species indigenous to New Zealand, were described and compared in the anatomical aspects. Qualitatively, growth rings were wide in the compression wood, intermediate in the lateral wood, and narrow in the opposite wood. Tracheid transition from early wood to late wood was very gradual in the compression wood but was more abrupt in both the lateral and opposite woods. When viewed transversely, compression wood tracheids showed a roundish outline except at the growth ring boundary but lateral and opposite wood tracheids were angular to rectangular in outline. Intercellular spaces were occasionally detected in the compression wood except in the late wood at the growth ring boundary but were absent from both the lateral and opposite woods. Slit-like extensions of the bordered pit openings caused by the location of pit apertures within short and narrow helical grooves were observed in the compression wood tracheids but not in the opposite or lateral wood tracheids. In the compression wood tracheids, fine striations in the form of fine checks or grooves were observed on the lumen surfaces and the innermost $S_3$ layer of secondary wall was absent. In the tracheids of lateral and opposite woods, the $S_3$ layer was sometimes absent but occasionally highly developed. Cross-field pits in the compression wood appeared to be piceoid due to slit-like pit apertures but those in the lateral and opposite wood tracheids showed cupressoid to taxodioid. Quantitatively, compression wood tracheids were somewhat shorter than those of opposite or lateral wood in stem but not different from the opposite or lateral wood tracheids in branch. The walls were thicker in the compression wood than in the lateral or opposite wood. Uniseriate rays in the compression wood were fewer than in the lateral or opposite wood.

• Journal of the Korean Wood Science and Technology
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• v.47 no.2
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• pp.189-199
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• 2019

This study addresses the biorefinery feedstock from Pinus densiflora. This raw material is a major tree species in the Republic of Korea; it is renewable, has cost-effective, and is readily available. In this study, steam explosion of P. densiflora was performed in a reactor at $225^{\circ}C$ and with 1 to 13 min reaction times with or without previous water impregnation. The combined severity factor (Ro), which is an expression relating the reaction temperature and reaction time used in the steam explosion treatment, ranged from 3.68 to 4.79. The influence of both impregnation and steam explosion conditions were investigated by examining color variations, chemical composition, and mass balance on the pretreated solids. The results showed that steam-exploded P. densiflora that was not impregnated with water exhibited significantly darker color (chroma 28.8-41.4) than water-impregnated and steam-exploded P. densiflora (chroma 18.8-37.3). The increased ${\alpha}$-cellulose and lignin contents were detected as the severity factor increased. Furthermore, the ${\alpha}$-cellulose and lignin contents in the non-impregnated/steam-exploded P. densiflora were higher than those in the water-impregnated/steam-exploded P. densiflora. However, the decreased holocellulose content was detected as the severity factor increased. In mass balance, the holocellulose yield from water-impregnated/steam-exploded P. densiflora was higher than that from the non-impregnated P. densiflora.

• Journal of the Korean Wood Science and Technology
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• v.30 no.1
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• pp.48-55
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• 2002

The essential oils were extracted from the needles of several softwood tree species, Pinus densiflora, Pinus koraiensis, Chamaecyparis obtusa and Chamaecyparis pisifera to investigate their biological activities. The antifungal activity by hyphal growth inhibition method was determined by three wood rot fungi, one mouldous fungi, and three tree pathogenic fungi and the antibacterial activity by paper disc method and turbidiometric method by three gram positive bacteria and one gram negative bacteria, Escherichia coli, were also tested. Antifungal activity was the best in the essential oil from C. obtusa, and the following was resulted in order of P. densiflora and P. koraiensis. The essential oil from P. densiflora showed higher antifungal activity against wood rot fungi than that from P. koraiensis while the result was contrary against tree pathogenic fungi. However, the antibacterial activity was the best in the essential oil from P. densiflora, and the following was in order of C. obtusa and P. koraiensis. From these results, the variation of biological activity seemed to be due to the chemical composition of essential oils.