• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.720-723
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• 2003

Electric stimulation of teeth is used for assessing pulp vitality. Because of very high and wide range of impedance of the enamel, electric pulp testers use high voltage, high output impedance and alternative current source. Most pulp testers use voltage stimulation method and their stimulating threshold levels significantly depend on each individual. Therefore, a constant current stimulator is necessary to minimize the effect of wide variation in enamel thickness. In this study, we constructed a constant current source type of pulp tester with the maximum current of 150 uA.

• 치과방사선
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• 제20권1호
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• pp.79-89
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• 1990

The incidence and several characteristic features of fused and geminated teeth were studied radiographically, with full mouth periapical radiogram and pantomogram, in 4201 patients of mixed dentition and 5358 patients of permanent dentition. The obtained results were as follows: 1. The prevalence was revealed to 2.86%, 0.32%, 0.33%, and 0.06% in deciduous fused tooth, permanent fused tooth, deciduous geminated tooth and permanent geminated tooth respectively, and these anomalies were occured in female more than male. 2. Fused teeth were observed predominantly in lower anterior teeth area, especially in lateral incisor and canine region, and many cases of deciduous geminated tooth were observed in upper central incisor region. 3. Congenital missing rates of succedaneous tooth in deciduous fused teeth were 57.1 %, 85.7%, 71.0%, 69.0% in upper right and left central-lateral incisor regions, lower right and left lateral incisor-canine regions, respectively. 4. Prevalence of dental caries was 42.3%, 18.8% and 5.6% in deciduous fused, deciduous geminated and permanent fused tooth, respectively. 5. In classifying of fused and geminated teeth into 9 types, by following appearance such as number of crown, root, pulp chamber and pulp canal of those teeth, it was more favorable that Type Ⅰ(2 crown, 2 root, 2 pulp chamber, 2 pulp canal) in deciduous fused tooth and Type Ⅸ (I crown, 1 root, 1 pulp chamber, 1 pulp canal) in permanent fused tooth, deciduous and permanent geminated tooth.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2003년도 추계학술발표논문집
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• pp.148-153
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• 2003

The influence of sizing, fiber and pigment type on coating penetration, using commercial paper and two types of handsheets as the base paper which were prepared from thermomechanical pulp(TMP) and hardwood bleached kraft pulp(KP) sized internally with alkyl ketone dimmer(AKD), was studied in terms of characteristics of coating holdout. Laboratory rod draw down coater was used for surface sizing and coating application. Characterization of coating penetration was done by measuring the roughness of the backside of coating layer. The backside of the coating was exposed by dissolving the fibers in a solution of cupriethylenedimine(CED). Data show that internal sizing of base paper is effective and surface sizing is more effective to prevent coating penetration. Comparing between the two types of base papers, backside roughness of coating layer of TMP sheet is much larger and sizing is more effective to reduce coating penetration than those of KP sheet. With regard to pigment type, clay is more effective than calcium carbonate for better coating holdout.

• 펄프종이기술
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• 제38권2호
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• pp.72-86
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• 2006

• 펄프종이기술
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• 제31권4호
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• pp.41-48
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• 1999

This study was intended to investigated the effect of pulp type and intital calendering on the properties of recycled fiber. As the number of recycling is increased, at least by the fourth recycling , the freeness of the SW-BKP and HW-BKP increased. And then that decrease after the fifth recycling. Especially the freeness of CTMP increased more rapidly than any other pulp in first recycling. And there was no difference of freeness in all kind of pulp by initial calendering . The speed of dewatering in making sheet consistetly became slow by proceeding recycling on condition of all calendering. and the order of the speed of dewatering was as followed. CTMP>HW-BKP>SW-BKP. However in case of HW-BKP, which was low -yield pulp, the tendency of the speed of dewatering was similar to that of CTMP which was high-yield pulp and had high content lignin . There was no change of fiber length and no effect of calendering by recycling of HW-BKP and CTMP. Howeverfiber length of SW-BKP generally decreased, especially in calendering of high temperature and high pressure conditions. The WRV of SW-BKP diminished by proceeding recycling but that of HW-BKP and CTMP diminished in the first recycling and then there was no change of the WRV of HW-BKP and CTMP. The contents of fines of HW-BKP consistently decreased by the fourth recycling and then increased in the fifth recycling . On the other hand there was no tendency in the content of fines of SW-BKP and CTMP by the number of recycling.

• 펄프종이기술
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• 제33권1호
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• pp.8-15
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• 2001

Presence of small amount of old newsprints printed with waterbased flexographic inks leads to a significant loss brightness of the deinked pulp by flotation process. Recently there has been an increased interest in employing neutral deinking processes to solve the problems associated with waterbased flexo ink. A comparative experimental study was performed to evaluate the efficiency of neutral deinking and conventional alkaline deinking for ONP furnishes contaminated with flexo ink. It was shown that neutral deinking provides significant improvements in brightness, yield and freeness as compared with alkaline deinking. Flotation efficiency was different depending upon the type of surfactants used in neutral deinking. The result of this study showed that alcohol type surfactant is superior to fatty acid type surfactant in neutral deinking efficiency.

• 펄프종이기술
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• 제39권4호
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• pp.7-13
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• 2007

Effects of pulp type, refining and filler type on the pore characteristics and physical properties of paper were investigated. HwBKP, SwBKP and BCTMP are used to study the effect of pulp type in this study. The effects of each filler (PCC, GCC and talc) and the combination of PCC/GCC were also studied. Highest bulk, pore volume and light scattering are obtained from BCTMP and PCC. It was found that the pore size and pore volume are important in light scattering in paper structure. It was found that PCC was the most effective filler for the improvement of the bulk and light scattering because of the increase in pore volume which can scatter light, but the increase of PCC content was not so effective in the improvement of bulk.

• 펄프종이기술
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• 제31권3호
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• pp.10-18
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• 1999

The influence of simple electrolyte or anionic trashes on cationic starch adsorption was examined using deinked pulp and bleached thermomechniical pulp. Adsorbed amounts of cationic starches increased slightly , then decreased abruptly as the concentration of simple electrolyte increased. This phenomenon was discussed based on the compression of electrical double layer and conformation change of starch molecules. Also, the effect of the type of simple electrolytes on starch adsorption was examined and discussed. Addition of sodium slilicate increased starch adsorption since it increased surface charge density of fibers. On the other hand, addition of kraft lignin decreased cationic demand of the pulp slurries and adsorbed amounts of cationic starches. Nonionic surfactant did not show any significant effect on the cationic demand of pulp slurries. When simple electrolytes were added to the stock , grater adsorption or cationic starches was obtained with starches of lower degree of substitution . On t도 other hand, amount of adsorbed starches decreased for lower DS starches when the concentration of anionic trashes increased.

• 펄프종이기술
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• 제36권1호
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• pp.49-60
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• 2004

Life Cycle Assessment for the pulp, which is mainly used as the raw material of fine paper, base paper for food packaging and paper cup, has been carried out in this study to consider environmental aspects by quantifying the environmental emission and to evaluate its environmental impact potential. The system boundary was selected from cradle to gate stage(raw material acquisition, transportation of raw material and product manufacturing) of the product. Environmental impact was divided into 8 categories considering Korean situation: abiotic resource depletion, global warming, ozone depletion, acidification, eutrophication, photochemical oxidant creation, ecotoxicity and human toxicity. In Life Cycle Impact Assessment(LCIA) methodology phase, Ecopoint, Eco-indicator 95 and Korean eco-indicator were used and the results carried out by each methodology were compared. The results from this study were also compared with those of foreign study to verify the reliability of the results. The results of the study could be utilized as the basic data for Environmental Management System(EMS), Design for Environment(DfE) and Type III eco-labeling in the paper and paper-related industry.

• Archives of Plastic Surgery
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• 제34권5호
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• pp.587-592
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• 2007

Purpose: In case of postburn flexion contracture of the fingers, skin graft, geometrical relaxation techniques, local flap, and free flap have been used. Among these procedures, full-thickness skin grafts from the inguinal area are widely used to reconstruct a postburn flexion contracture in the fingers. But there are many esthetic and functional problems in this procedure. Especially, hyperpigmentation of the skin-grafted fingers poses a troublesome problem, particularly in the patients who have dark colored skin. To solve the problem, we have used pulp graft which was harvested from the lateral aspect of great toe. In the present study, we report pulp graft, with which we have obtained a good result in the treatment of postburn flexion contracture of the fingers. Methods: Between September of 2004 and August of 2006, great toe pulp graft was performed to 20 sites of 15 patients. After release of the postburn flexion contracture using Z-plasty, the composite tissue (pulp) harvested from the lateral aspect of great toe was grafted on the raw surface. Moisture dressing with ointment and foam dressing material was performed. Stratum corneum of the graft got stripped off in two to four weeks after pulp graft. The color of the pulp graft was slightly reddish, then it became similar to the adjacent tissue. Results: There was complete take in all the patients who were treated with pulp graft. Great toe pulp graft provided similar color and texture to the adjacent skin, high rate of graft take, and left only a minimal scar at donor site. Conclusion: Thick keratin layer and inelastic nature of the pulp make this type of the graft much easier and simpler, and ensure a better take. Pulp graft is useful method for the reconstruction of the postburn flexion contracture in fingers.