• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.3
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• pp.1-6
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• 1998

Elementally Chlorine Free (ECF) bleaching will be superior than Totally Chlorine free (TCF) bleaching, not only because they have no significant difference in effluent toxicity, but also those pulps bleached by ECF have higher brightness, strength, yield, etc., over those by TCF. With this belief, this paper focused on the chemistry of chlorine dioxide decomposition and ionization, both in water solution and in pulp slurry. Special attention was paid to chlorate ion because there have been controversies as how it is formed and what its behavior to the end pH of pulp bleaching is. As a result, during ionization of chlorine dioxide with water, both chlorate and chlorite were found to increase with increasing pH, but during ionization with pulp, chlorite was found to increase with end pH while chlorate decreased with increasing end pH. In the case of ionization with water, the disproportion equation $2CIO_2 + OH^{-} \lightarrow H_2O + CIO_3^{-} + CIO_2^{-}$ was thought to become the main reaction with the increasing pH, while in the case of ionization with pulp, the reaction $HCIO + CIO_2^{-}\lightarow H^{+} + Cl^{-} + CIO_3^{-}$ was the main reaction contributing to the formation of chlorate. Based on this above opinion, the contrary results of chlorine dioxide ionization from different researchers were discussed and explained.

• Journal of the Korean Wood Science and Technology
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• v.26 no.1
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• pp.29-37
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• 1998

Alkali-soluble extracts were prepared from medium-sized barks of Radiata pine(Pinus radiata). There are difficulties in the production of extracts with uniform quality and in the preparation of adhesives with suitable viscosity. Ultrafiltration using an Amicon cell was subjected to fractionate extracts according to molecular sizes in order to overcome the above problem. The filtration efficiency was studied by using thin channel filtration systems. Adhesive manufacturing was also examined. Removal of particles greater than 0.45m from the extracts increased both filtration speed (flux) and yields of solids in the filtrates. Ultrafiltration with PM 10 membrane was very effective to fractionate and concentrate the extracts. Stiasny precipitates from the filtrates obtained by PM 10 membrane were very lower than that(83%) of the retentates. This ultrafiltration method was efficient for obtaining high yield purified phenolic compounds(mainly polyflavanoids) and thus important for preparing wood adhesives from barks. The extracts were shown excessive high viscosities at the concentrations required for adhesive formulation, but this high viscosity and short gelation time was reduced by lowering pH of the extracts and addition of urea. The highest bonding strength of plywoods(340g/$m^2$ of adhesive spreads) was achieved with adhesive formulated by 100parts of mixed alkali extracts and urea(70/30,w/w), 10parts of p-formaldehyde and 3.5parts of wheat flour at pH 6, and by hot pressing at the conditions of 12kg/$cm^2$ at $120^{\circ}C$ for 10 minutes.

• Journal of the Korean Society for Heat Treatment
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• v.4 no.3
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• pp.7-12
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• 1991

Effects of Mo content and aging conditions on the amount of retained austenite and mechanical properties of 18 Ni maraging steels were investigated. Maraging steels were fabricated with variation of Mo content. 3, 5, 7, 9% and heat treated by austenitizing at $840^{\circ}C$ for 1 hour and then aged at $480^{\circ}C$ for 0.5~100 hours. It was found that the amount of retained austenite after aolution treatment was negligible up to 5% Mo. 8 and 11 volume percents of retained austenite were obtained with 7 and 9% Mo respectively. The maximum hardness and yield strength without great loss of impact toughness were attained in the range of 4~8 hours of aging time at $480^{\circ}C$ with 5% Mo. It was concluded, as a result, that the optimum Mo content for the good combination of strength and toughness is to be 5% Mo.

• Journal of the Korean Society for Heat Treatment
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• v.28 no.4
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• pp.171-180
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• 2015

The variation in microstructure and texture during continuous annealing was examined in a series of 1.6% Mn-0.1% Cr-0.3% Mo-0.005% B steels with carbon contents in the range of 0.010 to 0.030%. It was found that microstructure of hot band consisted of ferrite and pearlite as a consequence of high coiling temperature, and eutectoid carbon content was between 0.011% and 0.016%. Martensite ranged in volume fraction from 1.5% to 4.0% when annealed at $820{\circ}C$ according to the typical continuous annealing cycle. The critical martensite content for the continuous yielding was about 4% from stress-strain curves. The continuous yielding was obtained in the 0.030% carbon steel and 0.010% to 0.020% carbon steels revealed some yield point elongation ranging from 0.8% to 2.2% in as-annealed conditions. Higher tensile strength in the higher carbon steel is due to both increase in the martensite volume fraction and ferrite grain refinement. Decreasing the carbon content to 0.01% strengthened the intensities of ${\gamma}$-fiber textures, resulting in the increase in the $r_m$ value, which was caused by the lower volume fraction of martensite. The higher carbon steels showed the lower $r_m$ value of about 1.0.

• Journal of Embryo Transfer
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• v.10 no.3
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• pp.229-236
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• 1995

The experiments reported here take advantage of the large number of in vitro matured and in vitro fertilized(IVM /IVF) bovine oocytes which can be produced, permitting the design of controlled experiments to establish a simple defined medium for the study of early embryo requirements. A total of 1,386 IVM /IVF oocytes were used to compare a simple defined medium(KSOM) with more complex culture conditions used successfully for culture of bovine embryos but do not permit study of specific requirements. All experiments were extensively replicated factorials. In Experiment 1, KSOM was superior to Menezo B$_2$ medium in producing morulae plus blastocysts from IVM /IVF oocytes(33 vs 20%, P<0.()5). The yield of morulae plus blastocysts with KSOM was 22% and with BRLC added was 30%. In Experiment 2, (a 2x2 factorial of KSOM with or without BRLC and 0, 1 ng /ml of platelet derived growth factor, PDGF) more morulae plus blastocysts (40%) were produced in KSOM-BRLC co-culture containing 1 ng /ml PDGF than in the control KSOM(12%). In Experiment 3, there was no dose response when 0, 1 and 5 ng /ml of PDGF were added. The results with simple defined KSOM medium are sufficiently promising to indicate that specific requirements of the embryo may be examined in future studies with KSOM as a base.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.3
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• pp.201-205
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• 1994

The objectives of this research are to determine the seasonal and varietal differences of total digestible nutrients(TDN) and in vitro dry matter digestibility(1VDMD) of tall fescue grown in Takwalyon areas, based on the data of preceding paper(Lee et al. 1994b). The results are may be summarized as follows : 1. The values of total digestible nutrients(TDN) and in vitro dry matter digestibility(1VDMD) in 1st cutting were lower than the values of 2nd and 3rd cutting, and it was due to different stages of growth and seasonal difference of climatic conditions in this areas. 2. The relative yield(RY) had negative significantly correlation with in vitm dry matter digestibility(1VDMD) of 1st cutting. 3. Total digestible nutrients(TDN) indicated high positive significant correlation with in vitro dry matter digestility (IVDMD) in all cuttings. 4. The variety of Johnstone showed a high values of total digestible nutrients(TDN) and in vitm dry matter digestibility(1VDMD) of 2nd and 3rd cutting, but Fuego was lower than the other varieties.

• The Plant Pathology Journal
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• v.29 no.2
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• pp.201-208
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• 2013

Drought stress is one of the major yield affecting factor for pepper plant. The effects of PGPRs were analyzed in relation with drought resistance. The PGPRs inoculated pepper plants tolerate the drought stress and survived as compared to non-inoculated pepper plants that died after 15 days of drought stress. Variations in protein and RNA accumulation patterns of inoculated and non-inoculated pepper plants subjected to drought conditions for 10 days were confirmed by two dimensional polyacrylamide gel electrophoresis (2D-PAGE) and differential display PCR (DD-PCR), respectively. A total of six differentially expressed stress proteins were identified in the treated pepper plants by 2D-PAGE. Among the stress proteins, specific genes of Cadhn, VA, sHSP and CaPR-10 showed more than a 1.5-fold expressed in amount in B. licheniformis K11-treated drought pepper compared to untreated drought pepper. The changes in proteins and gene expression patterns were attributed to the B. licheniformis K11. Accordingly, auxin and ACC deaminase producing PGPR B. licheniformis K11 could reduce drought stress in drought affected regions without the need for overusing agrochemicals and chemical fertilizer. These results will contribute to the development of a microbial agent for organic farming by PGPR.

• Journal of Welding and Joining
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• v.31 no.5
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• pp.26-34
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• 2013

Boiler equipment in power plant is always being operated in harsh conditions and severely exposed to the extreme environment of high temperature. Therefore periodically the state of devices should be checked, diagnosed, and analyzed to ensure the reliability of the equipment. Traditionally, such a diagnosis is based one or two physical properties of the sample taken from the equipment like hardness, microstructure, etc.. However, to enhance the confidence of the diagnosis, it is necessary to synthesize those properties together. This paper is to propose such a synthetic procedure for T23 which was developed to be used in $569^{\circ}C/596^{\circ}C$ condition. Creep test and accelerated degradation test were performed simultaneously, and the physical properties such as microstructure, tensile strength, yield strength, hardness, and indentation properties were measured. This paper proposes a method of determining the remaining life by quantitative comparison. It will provide the basis of evaluating life assessment more objective and reliable.

• Journal of the Korean Wood Science and Technology
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• v.19 no.4
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• pp.80-84
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• 1991

Lignocellulosic biomass including acetosolv ricestraw and spruce lignin were liquefied and converted into liquid hydrocarbons by catalytic hydroliquefaction reaction. These experimental works were carried out in 1-liter-capacity autoclave using 50% tetralin and m-cresol solution respectively as soluble solvent and Ni. Pd. Fe and red mud as catalyst. $H_2$ gas was supplied into the reactor for escaltion of deoxhydroenolysis reaction. Catalyst concentrations were 1 % of raw material based on weight. The ratio between raw materials and soluble solvent are 1g and 10cc. The reaction conditions are 400-$700^{\circ}C$ of reaction temperature, 10-50 atms of reaction pressure. The highest yield of hydrocarbon, so called "product oil" showed 32% and 5.5% of lowest char formation when red mud was used as catalyst. The product oil yields from those of other catalysts were in the range of 20-29%. The influence of different initial hydrogen pressures was examined in the range d 30-50 atms. A minimum pressure of 35 atms was necessary to obtain a complete recovery of souble solvent for recycling.

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.6
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• pp.21-28
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• 2004

This study aims to investigate the effects of partially distributed loads on the dynamic behaviour of steel parabolic arches by using the elasto-plastic finite element model based on the Von Mises yield criteria and the Prandtl-Reuss How rule. For this purpose, the vertical and the radial load conditions were considered as a distributed loading and the loading range is varied from 40% to 100% of arch span. Normal arch and arch with initial deflection were studied. The initial deflection of arch was assumed by the sinusoidal motile of ${\omega}_i\;=\;{\\omega}_O$ sin ($n{\pi}x/L$). Several numerical examples were tested considering symmetric initial deflection when the maximum initial deflection at the apex is fixed as L/1000. The analysis resluts showed that the maximum deflection at the apex of arch was occurred when 70% of arch span was loaded. The maximum deflection at the quarter point of arch span was occurred when 50% of arch span was loaded. It is known that the optimal rise to span ratio between 0.2 and 0.3 when the vertical or radial distributed load is applied. It is verified that the influence of initial deflection of radial load case is more serious than that of vertical load case.