• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.6
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• pp.154-163
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• 2015

Because of acute or chronic intoxication by carbon disulfide, viscose rayon industry is strictly subjected to environment regulatory approval. Recently, non-wood fibers are frequently considered as a raw materials for the manufacture of specialty paper for the higher physical strength and functionality. Among the non-wood fibers, hemp bast fiber is one of the most widely used materials in viscose rayon yarn industries. In this study, the handsheet for manufacturing the viscose rayon yarn was prepared with wood pulp fibers and hemp bast fibers. The proper mixing ratio of wood fibers and hemp bast fibers with dry-strength agent and nano-celluloses was analysed in terms of physical and mechanical strength of sheet for viscose rayon yarn. The papermaking conditions for high mechanical strength of sheet were obtained by mixing the SwBKP and HwBKP fibers with freeness level of 200 mL CSF. The dual polymer system by controlling the addition ratio of PVAm and anionic PAM was also important. The addition of nano-cellulose into wet-end furnishes increased the physical strength of sheet, and improved the paper structure for the production of viscose rayon yarn.

• Earthquakes and Structures
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• v.7 no.1
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• pp.101-117
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• 2014

This paper presents a reliability-based analysis on seismic performance of timber-steel hybrid shear wall systems. Such system is composed of steel moment resisting frame and infill wood frame shear wall. The performance criteria of the hybrid system with respect to different seismic hazard levels were determined through a damage assessment process, and the effectiveness of the infill wood shear walls on improving the seismic performance of the hybrid systems was evaluated. Performance curves were obtained by considering different target non-exceedance probabilities, and design charts were further established as a function of seismic weight. Wall drift responses and shear forces in wood-steel bolted connections were used as performance criteria in establishing the performance curves to illustrate the proposed design procedure. It was found that the presence of the infill wood shear walls significantly reduced the non-performance probabilities of the hybrid wall systems. This study provides performance-based seismic evaluations on the timber-steel hybrid shear walls in support of future applications of such hybrid systems in multi-story buildings.

• Journal of the Korean Wood Science and Technology
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• v.35 no.5
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• pp.67-75
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• 2007

As a part of abating the formaldehyde emission of urea-formaldehyde (UF) resin adhesive by lowering formaldehyde to urea (F/U) mole ratio, this study was conducted to investigate properties of UF resin adhesive with different F/U mole ratios. UF resin adhesives were synthesized at different F/U mole ratios of 1.6, 1.4, 1.2, and 1.0. Properties of UF resin adhesives measured were non-volatile solids content, pH level, viscosity, water tolerance, specific gravity, gel time and free formaldehyde content. In addition, a linear relationship between non-volatile solids content and sucrose concentration measured by a refractometer was established for a faster determination of the non-volatile solids content of UF resin. As F/U mole ratio was lowered, non-volatile solids content, pH, specific gravity, water tolerance, and gel time increased while free formaldehyde content and viscosity were decreased. These results suggested that the amount of free formaldehyde strongly affected the reactivity of UF resin. Lowering F/U mole ratio of UF resin as a way of abating formaldehyde emission consequently requires improving its reactivity.

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.1
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• pp.80-86
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• 2007

In this study we experimented setting time and basic properties as waste wood fiber and sodium silicate substitution rate to reuse waste wood fiber produced in construction field to wood chip board. To do this construction waste woods were crushed with the size less than 10mm, mixed with the rate of 1:2, 2.5, 3, and added sodium silicate with the rate of 0, 5% of cement content. The results are as follows. As the substitution rate of construction waste wood was increased delay of setting time was also increased, and the batch of adding 5% accelerator had a 13~17 hours faster setting time than non accelerator batch. The compressive strength was lower as wood substitution rate was higher, and as the specific gravity was higher, the strength was also higher. As wood substitution rate was higher, heat conductivity was lower, and as specific gravity was higher, heat conductivity also was higher.

• Journal of the Korean Wood Science and Technology
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• v.40 no.4
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• pp.257-267
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• 2012

In this study, the method for heat treating wood using superheated steam (SHS) was designed and applied. The physical and mechanical properties of Korean Pine (Pinus koraiensis Siebold & Zucc.) lumber heat-treated by SHS at $170^{\circ}C$ and 0.4 MPa for 10 hours were compared with those of non-treated and normal heat-treated wood. The amount of adsorbed water and equilibrium moisture content of the SHS treated wood were lower than non-treated wood. On the other hand the compressive strength parallel to grain and the bending strength of SHS treated wood were higher than those of non-treated wood. The hygroscopicity of SHS treated wood was similar to normal heat treated wood at $220^{\circ}C$. Internal checks that often occur during normal heat treatment were not developed at SHS treatment. Also, SHS treatment are effective in control of internal checks occurrence and resin exudation.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.43-49
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• 2006

The surface and pore structure of cellulose fibers have a significant impact on the properties and performance in applications. Cellulase enzymatic hydrolysis of cellulose fibers can result in changes to the surface and pore structure thus providing a useful tool for fiber modification. This research characterizes these changes using various test methods such as fiber dimension, water retention value, hard-to-remove water content, freezing and non-freezing bound water content, polymer adsorption, and crystallinity index. For a high-dosage enzyme treatment (0.10 g/g), the fiber length was significantly decreased and the fibers were 'cut' in the cross direction, not in the axial direction. The swelling capacities as measured by the WRV and HR water content increased for the high-dosage treatment. Three independent measurements (non-freezing bound water, polymer adsorption, and crystallinity index) are in good agreement with the statement that the amorphous regions of cellulose fibers are a more readily available substrate relative to crystalline regions. Based on the experimental results obtained herein, a model was proposed to explain surface and pore structure modification of cellulose fibers via enzymatic treatment.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.3
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• pp.35-41
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• 2009

The new way of utilization of Hanji need to develop for adding high value added. An watermarked Hanji was prepared with non-mulberry mixed fibers and the properties were investigated. The mechanical properties of non-mulberry fiber mixed Hanji were very similar to mulberry fiber Hanji. The non-mulberry fiber mixed Hanji was a little brighter than original Hanji. The air permeability and pore size of the hot pepper fiber mixed Hanji were decreased depending on the content of hot pepper fiber. The printing ability of watermarked Hanji made of non-mulberry mixed fibers was higher than that of original paper mulberry Hanji. The preservation properties of non-mulberry fiber mixed watermarked Hanji were almost same as those of the original Hanji.

• Journal of the Korean Wood Science and Technology
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• v.10 no.3
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• pp.196-196
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• 1982

There is a heavy stocked wood volume in the forest of Kang-Won Province compared with the other forests of Korean Provinces. It mainly, however, consists of non-productive and inferior hardwoods and shrubs which grows naturally. -This naturally grown hardwood forest should be cut and reforested with more economical confierous and diciduous tree species by artificial and natural regeneration under the positive government support. This study was carried out to survey the reasonable and economical utilization measures on harvesting wood products when existing hardwood forest should be cut primarily. This is the rust report on the resources and the classification of tree species by the uses of wood growing in the hardwood forest of Kang-Won Province. According to the investigation, 321 hardwood species are growing in this forest, and 141 species of them are extremely not suitable for wood production. The usable species as fuel wood was 180, and these are able to classify into the 22 groups by the uses of wood.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.349-352
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• 2006

The conventional pulping processes in Iran were reviewed in this paper. On account of forest resources restriction, a considerable extent of non-harvestable hardwood forests, the possibility of accessable non-wood resources and Poplar fast-growing species for using in pulp and paper industry was investigate. The cultivated area and abundance of each mentioned raw material (Wheat Straw, Sugarcane Bagasse, Poplars) were specified and the quality of their produced papers were compared in strength and opacity properties. Spruce species data was used for experiments comparisons. Regarding to environmental pollutions, low yield, inflexibility in wood and non-wood species resulted from the existent conventional processes of paper manufacturing, APMP is recommended due to high quality paper, desirable opacity properties, high yield and also the usage for all the raw materials.

• Entomological Research
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• v.48 no.5
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• pp.372-383
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• 2018

Leptocimbex formosanus group of Leptocimbex Semenov 1896, Cimbicidae is defined and the relationships and characteristics are provided. Two new species of this group are described from Hunan and Yunnan Provinces in China: Leptocimbex shinoharai Yan & Wei sp. nov. and L. naitoi Yan & Wei sp. nov. Redescriptions of the three known species of L. formosanus group (L. formosanus Enslin 1911, L. dendrobii Rohwer 1915 and L. nigropropodea Wei & Deng 2002) and a key to all known species of this group are provided.