• Food Science of Animal Resources
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• v.35 no.1
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• pp.130-136
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• 2015

This study was conducted to evaluate the quality properties of emulsion-type pork sausages when pork fat is replaced with vegetable oil mixtures during processing. Pork sausages were processed under six treatment conditions: T1 (20% pork fat), T2 (10% pork fat + 2% grape seed oil + 4% olive oil + 4% canola oil), T3 (4% grape seed oil + 16% canola oil), T4 (4% grape seed oil + 4% olive oil + 12% canola oil), T5 (4% grape seed oil + 8% olive oil + 8% canola oil), and T6 (4% grape seed oil + 12% olive oil + 4% canola oil). Proximate analysis showed significant (p<0.05) differences in the moisture, protein, and fat content among the emulsion-type pork sausages. Furthermore, replacement with vegetable oil mixtures significantly decreased the ash content (p<0.05), increased water-holding capacity in emulsion-type pork sausages. Also, cholesterol content in T6 was significantly lower than T2 (p<0.05). In the texture profile analysis, hardness and chewiness of emulsion-type pork sausages were significantly (p<0.05) decreased by vegetable oil mixtures replacement. On the contrary, cohesiveness and springiness in the T4 group were similar to those of group T1. The unsaturated fatty acid content in emulsion-type pork sausages was increased by vegetable oil mixtures replacement. Replacement of pork fat with mixed vegetable oils had no negative effects on the quality properties of emulsion-type pork sausages, and due to its reduced saturated fatty acid composition, the product had the quality characteristics of the healthy meat products desired by consumers.

• Fire Science and Engineering
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• v.25 no.3
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• pp.1-7
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• 2011

This paper studied analysis of deflagration rapid propagation of burning through only a few second and fire cause into the Busan indoor shooting range. We carried out combustion experiment of sound-absorbing materials extensively used, to analyze propagation path of burning in indoor shooting range. From the experimental results, general sound-absorbing materials were rapid burned simultaneously with ignition and in case of attached gunpowder residue, they were burning about tripled by comparison with general sound-absorbing materials. The incombustibility sound-absorbing materials had all gone out simultaneously with ignition, but they were burning similar to general type materials in case of attached gunpowder residues. In order to analysis of the cause of fire, we calculated kinetic energy of bounced off bullet, from result, if the bounced off bullet impacted gunpowder residues, the gunpowder residues were possible to ignite by the bullet.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.16 no.3
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• pp.121-126
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• 2006

HVOF thermal spray coating of Co-alloy T800 is progressively replacing the classical hard coatings such as chrome plating because of the very toxic $Cr^{6+}$ ion known as carcinogen causing lung cancer. For the study of the possibility of replacing of chrome plating, the wear properties of HVOF Co-alloy T800 coatings are investigated using the reciprocating sliding tester both at room and at an elevated temperature of $1000^{\circ}F\;(538^{\circ}C)$. The possibility as durability improvement coating is studied for the application to the high speed spindles vulnerable to frictional heat and wear. Wear mechanisms at the reciprocating sliding wear test are studied for the application to the systems similar to the sliding test such as high speed spindles. Wear debris and frictional coefficients of T800 coatings both at room and at an elevated temperature of $1000^{\circ}F\;(538^{\circ}C)$ are drastically reduced compared to those of non-coated surface of parent substrate Inconel 718. This study shows that the coating is recommendable for the durability improvement coatings on the surfaces vulnerable to frictional heat. The sliding surfaces are weared by the mixed mechanisms such as oxidative wear, abrasion by the sliding ball slurry erosion by the mixture of solid particles and small drops of the melts and semi-melts of the attrited particles cavitation by the relative motions among the coating, sliding ball, the melts and semi-melts. and corrosive wear. The oxide particles and the melts and semi-melts play roles as solid and liquid lubricant reducing the wear and friction coefficient.

• Carbon letters
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• v.8 no.4
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• pp.326-334
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• 2007

In this study, graphite composites were fabricated by warm press molding method to realize commercialization of PEM fuel cells. Graphite composites have been considered as alternative economic materials for bipolar plate of PEM fuel cells. Graphite powder that enables to provide electrical conductivity was selected as the main substance. The graphite powder was mixed with phenolic resin and the mixture was pressed using a warm press method. First of all, the graphite powder was pulverized with a ball mill for the dense packing of composite. As the ball milling time increases, the average size of particles decreases and the size distribution becomes narrow. This allows for improvement of the uniformity of graphite composite. However, the surface electrical resistivity of graphite composite increases as the ball milling time increases. It is due to that graphite particles with amorphous phase are generated on the surface due to the friction and collision of particles during pulverizing. We found that the contact electrical resistivity of graphite particles increases as the particle size decreases. The contact electrical resistivity of graphite powders was reduced due to high molding pressure by warm press molding. This leads to improvement of the mechanical properties of graphite composite. Hydrogen gas impermeability was measured with the graphite composite, showing a possibility of the application for bipolar plate in fuel cell. And, I-V curves of the graphite composite bipolar plate exhibit a similar performance to the graphite bipolar plate.

• Journal of Technologic Dentistry
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• v.25 no.1
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• pp.9-20
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• 2003

Using a nickel-chrome casting alloy called 'Rexillium V' which is also available as base metal alloy for dental ceramic crown, 4 types of mixtures(A, B, C, D) with old and new metal were prepared for cyclic casting. The results of cyclic casting can be outlined as follows: 1. For Vickers hardness after casting, specimen A and D tended to have lower hardness in the course of cyclic casting, while specimen B and C tended to higher hardness. 2. The results of X-ray diffraction analysis showed that major crystal phase contained nickelchrome compounds and carbide. 3. The observation results of SEM photographs after cyclic casting show that there was a significant tendency to have similar structures among experimental groups. 4. The results of EDX analysis after cyclic casting showed that there were little differences in chemical composition between parent metal and base metal alloy. Although industrial nickel-chrome cast alloy did not show any significant change in material properties even through cyclic casting over several times, it is recommended that more there be more in-depth studies on how to detect any potential corrosion, discoloration and toxication of dental ceramic crown implanted in patient's oral cavity.

• Journal of Hydrogen and New Energy
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• v.15 no.2
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• pp.98-107
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• 2004

Modified Ni/YSZ cermets for high temperature electrolysis were synthesized by dry or wet mechanical alloying methods. The Ni/YSZ composit particle was directly fabricated from the ball milling of Ni and YSZ powder or obtained from the reduction of NiO/YSZ particle after the ball milling of NiO and YSZ. In the case of the NiO/YSZ composite particle, the dry milling increased the average particle size whereas the wet milling decreased the size. The dry milling showed that fine YSZ particles were distributed over large Ni surfaces while Ni and YSZ particles similar in size were well mixed in the wet milling method. These features were the same in the Ni/YSZ composite particle prepared from Ni and YSZ powders. The electrical conductivity of the wet-milled Ni/YSZ cermet showed the highest value of $2{\times}10^2S/cm$ among the specimens and this value was increased to $1.4\times10^4S/cm$ after the sintering at $900^\circ{C}$ for 1 h.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.5
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• pp.597-607
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• 2004

Purpose: This study was peformed to investigate the retrievability of the cemented crown from the cementation type implant abutment. Material and method: The cementation type implant abutments (NEOBIOTECH implant abutment regular, 3 degree taper, 10mm length, 4mm diameter, Ti grade III, machined surface. Hwasung, Kyunggi-do) and cemented crowns were divided into 3 groups, depending on their hole angles formed in the crowns for their retrievability. The abutments and crowns were luted with 4 kinds of cements and separation test using metal wedge was executed with Instron 4465 Universal Testing Machine and the maximum impact force of the modified crown ejector was measured. Results and conclusion : 1. All of the cementation type implant abutments and cemented crowns were separated with relatively small force by metal wedge. 2. The retrieving force was minimum when the metal wedge was applied perpendicular to the axis of abutment. 3. The force for retrieving crowns from abutments was maximum in resin cement group, and reduced in orders of zinc phosphate cement, glass ionomer cement and zinc oxide eugenol cement. 4. The maximum force obtained by the crown ejector was higher than the retrieval force in ZOE and GI cement and lower than that in ZPC and resin cement. 5. If it has similar conditions clinically, the cemented crowns luted with 2 types of cements (ZOE, GI cement) can be safely retrieved from the cementation type implant abutments by the modified crown ejector.

• Journal of Periodontal and Implant Science
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• v.27 no.2
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• pp.411-424
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• 1997

The purpose of this study was to evaluate in vitro the effects during subgingival calculus removal using Nd:YAG laser. The study group was consisted of 30 teeth with advanced periodontal disease extracted before the start of periodontal therapy. The specimens were divided into 8 different groups : 1) untreated control 2) scaling and root planing only 3) laser treated using 150mJ/pulse, 1sec, 5sec, contact mode 4) laser treated using 200mJ/pulse, 5sec, contact mode 5) laser treated using 150mJ/pulse, 1sec, non-contact mode 6) laser treated using 200mJ/pulse, 5sec, non-contact mode 7) laser treated using l5OmJ/pulse, 1sec, contact mode with water irrigation 8) laser treated using 200mJ/pulse, 5sec, contact mode with water irrigation. All specimens were prepared for evaluation by scanning electron microscopy(SEM). Specimens from Group 2 exhibited a smear layer of scale like texture with parallel instrument tracks resulting from curet use. Specimens treated by contact mode, Group 3 and 4 featured surface changes not observed· in controls such as charring, randomly distributed pitting and crater formation, and melting down of the tooth material and calculus. Specimens treated by noncontact mode, Group 5 and 6 featured similar surface changes observed in contact mode. However, the differences between contact and non-contact groups not significant. Specimens treated by contact mode with water irrigation, Group 7 and 8 featured slight surface change compared to other groups. The results suggested that Nd: YAG laser did not completely remove the subgingival calculus but was possible the application as adjunctive method.

• Journal of Periodontal and Implant Science
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• v.23 no.2
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• pp.345-351
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• 1993

Various alloplastic materials have been used on the periodontally diseased ossous defects. Hydroxyapatite, which is used the most common alloplastic material is a non-resorbable form of calcium phosphate and natural coral which is a biodegradable by carbonic anhydrase in osteoclast was introduced recently. The purpose of the present study was to evaluate the clinical effects of porous hydoxyapatite and natural coral on the human periodontal defects. Four males and three females who had adult periodontitis were selected for this study. The teeth that had similar bone loss radiographically and periodontal pocket deeper than 5mm were selected. Gingival recession, pocket depth, plaque index(Silness & Loe), sulcus bleeding index and tooth mobility (measured by Periotest$^{(r)}$) were examined before graft. Before insertion of alloplastic materials, the depth from CEJ to bone crest and from CEJ to base of the osseous defect was recorded. Porous particulate hydroxyapatite(Interpore 200$^{(r)}$, A group) was place on the defect and natural coral(Biocoral$^{(r)}$, B group) was placed on the defect of the opposing tooth. Six months post-surgically the same parameters were recorded by reentry procedures. A and B group showed 0.6mm of mean recession. Mean reduction of pocket depth were 5mm for A group and 4.9mm of B group. Reduced SBI and tooth mobility were recorded. Osseous defect fills of the original defects were 2.9mm for A and 3mm for B group. Percentage defect fills were 71% for A and 59% for B group. The difference of defect fill between pre- and post-insertion was statstically significant(p<0.05). But the difference between the two groups was not significant statistically(p<0.05). The clinical impression at 6 month re-entry and the numerical date indicate that natural coral as well as porous particulate hydoxyapatite has a definite potential as an alloplastic implant in the treatment of periodontal osseous defects.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.1
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• pp.12-20
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• 2007

Purpose: The purpose of this study was to compare the fracture strength of the zirconia monolithic all-ceramic crowns according to the thickness (0.5mm, 0.8mm, 1.1mm) and metal-ceramic crowns (1.0mm, 1.5mm) Material and method: Twelve crowns for each of 3 zirconia crown groups were fabricated using CAD/CAM system (Kavo, Germany) and twelve crowns for each of 2 metal-ceramic crown groups were made by the conventional method. All crowns were luted to the metal dies using resin cement. Half of the specimens were exposed to thermocycling ($5-55^{\circ}C$, 1 Hz) and cyclic loading (300,000 cycles, 50N). Subsequently, all crowns were mounted on the testing jig in a universal testing machine. The load was directed at the center of crown with perpendicular to the long axis of each specimen until catastrophic failure occurred. Analysis of variance and Tukey multiple comparison test (P<.05) were used for statistical analysis of all groups, and paired t-test (P<.05) was followed for statistical comparison between each groups' fracture load before and after cyclic loading. Results: 1. The fracture strength of the zirconia monolithic crowns and the metal-ceramic crown increased as thickness increased (P<.05). 2. The cyclic loading and thermocycling significantly decreased the fracture strength of the zirconia monolithic crowns (P<.05). 3. The standard deviation of fracture strength of the zirconia monolithic crowns was very low. Conclusion: The fracture strength of the zirconia monolithic crowns for the posterior area tends to be higher with thickness increased and 0.8mm or over in thickness is recommended to have similar or over the fracture strength of metal-ceramic crowns.