• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.2
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• pp.26-33
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• 2009

A new testing method to evaluate the deposition potential of white pitch was developed. The new method involves depositing the potential white pitch particles on the air bubble covered plastic film in the pitch deposit tester (PDT) developed by KRICT and analysing the deposited area of white pitch using an image analyzer. In addition, the effect of two important factors (pH and calcium hardness) on white pitch deposition potential was elucidated. When pH of the coated broke stock was increased from neutral to alkali or the calcium hardness of the stock was decreased, the pitch deposit area was decreased, implying that these two factors have to be controlled during the evaluation of pitch deposition potential. It was found that hydrophobicity of the surface of latex binding films repulped is a key factor influencing white pitch deposition.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.6
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• pp.43-49
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• 2012

In this work, the non-ionic polyethylene oxide(PEO)/phenolic formaldehyde resin(PFR) retention system, which was less affected by furnish charge, was analyzed for possibility and effectiveness when using recycled stock. When the micropolymer was added at the PEO/PFR retention system and the PAM/bentonite retention system, performance of retention and drainage was improved. When the cationic micropolymer was added on the PEO/PFR retention system, the highest retention was achieved. The Polyacrylamide(PAM)/bentonite system induced flocculation of white pitch by electrostatic flocculation. On the other hand, the non-ionic PEO/PFR retention system induced less flocculation of white pitch than the PAM/bentonite retention system.

• Journal of Biosystems Engineering
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• v.26 no.2
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• pp.177-188
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• 2001

This research was carried out to examine the optimum design conditions of a vertical small-scale milling machine where the rough rice is processed directly into the white rice in one pass. Effects of the main spindle speed, feed screw pitch and ceramic coating length of the roller on various milling characteristics such as white rice processing capacity, electric energy consumption, rice temperature increase, broken rice ratio, moisture reduction, outlet force and crack ratio increase were studied. The results are as follows. 1. The maximum white rice processing capacity and the lowest crack ratio increase, were obtained from a machine with specification: main spindle speed of 970rpm having a feed screw pitch of 19㎜. 2. The minimum electric energy consumption was obtained with the main spindle speeds of 900 and 970rpm respectively having a feed screw pitch of 19㎜. 3. The rice temperature was increased as the feed screw pitch decreased and the main spindle speed increased. 4. Broken rice ratio was relatively low with the range of 0.8∼1.3%. 5. Moisture content loss was with the range of 0.05∼0.4%. 6. The highest outlet force was 0.72kg$\_$f/ with 900rpm of the main spindle speed and 19㎜ of the feed screw pitch and the lowest outlet force was 0.18∼0.34kg$\_$f/ with 970rpm of the main spindle speed and 16㎜ of the feed screw pitch. 7. The optimum design conditions for the vertical small-scale milling machine were obtained at 970rpm of the main spindle speed, 19㎜ of the feed screw pitch and 20㎜ of the ceramics coating length.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.575-577
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• 2009

Traditionally, tire made a role of function, which is supporting vehicle load, making brake, transferring, traction etc. So, there are a lot of studying for the tire. especially, tire noise is one of the most important parameter in the car noise. this thesis shows the method how to reduce the tire noise by using the optimal pitch sequence. Because the optimal pitch sequence prevents tire from generating the pure tone while driving the car on the ground.

• Journal of Korea Foresty Energy
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• v.17 no.1
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• pp.56-70
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• 1998

This study was carried out to investigate the structural characteristics of kraft lignin and the wood degrading characteristics, the productivity of ligninolytic enzymes and the enzymatic degradation of kraft lignin by white-rot fungi. To purify kraft lignin, precipitation of kraft pulping black liquors of pitch pine meal was done by titration with lN $H_{2}SO_{4}$ reaching to pH 2, and isolation of the precipitates done by centrifugation. The isolated precipitates from pitch pine were redissloved in lN NaOH, reprecipitated by titration with lN $H_{2}SO_{4}$, washed with deionized water, and kept ofr analysis after freeze drying. Fractionation of the precipitates in solution by successive extraction with $CH_{2}Cl_{2}$ and MeOH, and the fractionates were named SwKL, SwKL I, SwKL II, and SwKL III for pitch pine kraft lignin. The more molecular weights of kraft lignin increased, the less phenolic hydroxyl groups and the more aliphatic hydroxyl groups. Because as the molecular weights increased, the ratio of etherified guaiayl/syringyl(G/S ratio) and the percentage were increased. The spectra obtained by 13C NMR and FTIR assigned by comparing the chemical shifts of various signals with shifts of signals from autherized ones reported. The optimal growth temperature and pH of white-rot fungi in medium were $28^{\circ}C$ and 4.5-5.0, respectively. Especially, in temperature and pH range, and mycelial growth, the best white-rot fungus selected was Phanerochaete chrysosporium for biodegradation. For the degradation pathways, the ligninolytic fungus jcultivated with stationary culture using medium of 1% kraft lignin as a substrate for 3 weeks at $28^{\circ}C$. The weight loss of pitch pine kraft lignin was 15.8%. The degraded products extracted successively methoanol, 90% dioxane and diethyl ether. The ether solubles were analyzed by HPLC. Kraft lignin degradation was initiated in $\beta$-O-4 bonds of lignin by the laccase from Phanerochaete chrysosporium and the degraded compounds were produced from the cleavage of $C\alpha$-$C\beta$ linkages at the side chains by oxidation process. After $C\alpha$-$C\beta$ cleavage, $C\alpha$-Carbon was oxidized and changed into aldehyde and acidic compounds such as syringic acid, syringic aldehyde and vanilline. And the other compound as quinonemethide, coumarin, was analyzed. The structural characteristics of kraft lignin were composed of guaiacyl group substituted functional OHs, methoxyl, and carbonyl at C-3, -4, and -5 and these groups were combinated with $\alpha$ aryl ether, $\beta$ aryl ether and biphenyl. Kraft lignin degradation pathways by Phanerochaete chrysosporium were initially accomplished cleavage of $C\alpha$-$C\beta$ linkages and $C\alpha$ oxidation at the propyl side chains and finally cleavage of aromatic ring and oxidation of OHs.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.11a
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• pp.291-295
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• 2006

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2009.10a
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• pp.107-121
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• 2009

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2007.04a
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• pp.398-403
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• 2007

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2008.10a
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• pp.90-95
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• 2008

• Journal of the Korean Wood Science and Technology
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• v.10 no.3
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• pp.45-45
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• 1982

There are many important exotic species in Korea, such as white pine, pitch pine, jack pine, oak, ash, etc. Some of them are already being used for various construction purposes, in spite of their history imported to and cultivated in Korea being very young. No study was carried out on the various properties of these exotic species, which arc needed for their proper use at present.