• Elastomers and Composites
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• v.57 no.4
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• pp.215-221
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• 2022

In this study, high-penetration asphalt with low greenhouse gas emissions was used in the asphalt mixing process to reduce the carbon emissions during the reaction due to its capacity to be produced even at low temperatures. In effect, cationic, anionic, and non-ionic dispersants were added and mixed in different feeding ratios, seeking an effective dispersion of the modifiers (SIS, PS, TPEE, and SEBS) into the high-penetration asphalt matrix and forming an asphalt binder with a melting point of 120 ℃. The compatibility of the modifiers and the high-penetration asphalt was examined using SEM and DSC techniques, and the role of NDP-1 as a dispersant was carefully investigated with respect to dissolution time. The analyses showed that: (1) the dispersibility of the asphalt binder is good when the non-ionic dispersant is used; (2) as the concentration of the non-ionic dispersant increases, the dissolution time decreases and the domain size contracts; (3) the ND70-PS has the shortest dissolution time, the lowest agglomeration rate, and a single Tg value.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.11
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• pp.1719-1723
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• 2010

The purpose of this study was to verify feasibility of using a ATP Luminometer, real-time hygiene monitoring tool for food contact surfaces in foodservices. For this, 54 cutting boards, 70 knives, 21 rubber gloves in 4 institutional foodservices were studied. ATP (RLU: relatively light unit) values by ATP Luminometer were compared with APC (CFU: colony forming unit) of swabbing culture method using aerobic count plates of 3M petrifilm. ATP ranged from 0 RLU/$cm^2$ to 64693 RLU/$cm^2$ on knives, from 0.1 RLU/$cm^2$ to 6743.6 RLU/$cm^2$ on cutting boards and from 31 RLU/$cm^2$ to 465635 RLU/$cm^2$ on the rubber gloves. APC ranged from 0 CFU/$cm^2$ to 166667 CFU/$cm^2$ on knives, from 0 CFU/$cm^2$ to 1000 CFU/$cm^2$ on cutting boards and from 0 CFU/$cm^2$ to 730000 CFU/$cm^2$ on the rubber gloves. To express the degree of association between ATP and APC, a linear regression was performed. There were significant positive correlations found between log RLU and log CFU on the knives (r=0.84, p<0.001), the cutting boards (r=0.79, p<0.001), the rubber gloves (r=0.78, p<0.001). Results of this study showed the possibility that ATP bioluminescence technique can be used as the monitoring tool for surface hygiene in foodservices.

• Elastomers and Composites
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• v.48 no.3
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• pp.225-231
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• 2013

In this study, we observed the effect of carboxylated SBR latex and zinc oxide on styrene-butadiene-styrene( SBS) composites for improving abrasion and debris. SBS composite, which added only silica, showed poor mechanical properties, NBS abrasion, and debris, caused by strong filler-filler interaction of silica. In case of adding carboxylated SBR latex, mechanical properties, NBS abrasion and debris of SBS composite were improved. Because of carboxyl group of carboxylated SBR latex interacted with silanol group of silica. Both carboxylated SBR latex and zinc oxide were added, SBS composite showed highest mechanical properties, NBS abrasion, and debris by forming ion cluster between carboxylated SBR latex and zinc oxide. By FT-IR analysis, ion clusters were confirmed that observed zinc carboxylated group stretch peak at $1550{\sim}1650cm^{-1}$ range. SBS composite, SC-4, showed excellent mechanical properties ; tensile strength $156kgf/cm^2$, elongation 936%, tear strength 59.4kgf/cm ; and excellent abrasion characteristics ; NBS abrasion 338%. Also, debris of SC-4 was minimized and showed wave-shape in fracture surface.

• Transactions of Materials Processing
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• v.15 no.1 s.82
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• pp.9-14
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• 2006

In the present research, the simultaneous punching of ultra small size hole of $2\~10\;{\mu}m$ in diameter on flat rolled thin metal foils was conducted with elastic polymer punch. Workpiece used in the present investigation were the rolled pure copper of $3{\mu}m$ in thickness and CP titanium of 1.5fm in thickness. The metal foils were punched with the dies and arrays of circular and rectangular holes were made. The process set-up is similar to that of the flexible rubber pad farming or Guerin process. Arrays of holes were punched successfully in one step forming. The punched holes were examined in terms of their dimensions. The effects of the wafer die hole dimension and heat treatment of the workpiece on ultra small size hole formation of the thin foil were discussed. The process condition such as proper die shape, pressure, pressure rate and diameter-thickness ratio (d/t) were also discussed. The results in this paper show that the present method can be successfully applied to the fabrication of ultra small size hole away in a one step operation.

• Elastomers and Composites
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• v.46 no.3
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• pp.257-261
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• 2011

We introduce a novel method that could modify neat asphalt. A polymer-forming monomer, dimethylphenol( DMP) was added to the neat asphalt and polymerization was occurred autonomously, without adding any external catalyst for the polymerization, only with oxygen molecules in the air. The polymer produced in the asphalt was polyphenyleneoxide( PPO) and it enhanced the mechanical properties of the asphalt. Compared with the neat asphalt, the tenacity and toughness of the DMP-modified asphalt were two and half times and three times high, respectively.

• Journal of Electrochemical Science and Technology
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• v.12 no.1
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• pp.74-81
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• 2021

Silicon (Si) is recognized as a promising anode material for high-energy-density lithium-ion batteries. However, under a condition of electrode comparable to commercial graphite anodes with low binder content and a high electrode density, the practical use of Si is limited due to the huge volume change associated with Si-Li alloying/de-alloying. Here, we report a novel core-shell composite, having a reversible capacity of ~ 500 mAh g-1, by forming a shell composed of a mixture of nano-Si, graphite nanosheets and a pitch carbon on a spherical natural graphite particle. The electrochemical measurements are performed using electrodes with 2 wt % styrene butadiene rubber (SBR) and 2 wt.% carboxymethyl cellulose (CMC) binder in an electrode density of ~ 1.6 g cm-3. The core-shell composites having the reversible capacity of 478 mAh g-1 shows the outstanding capacity retention of 99% after 100 cycles with the initial coulombic efficiency of 90%. The heterostructure of core-shell composites appears to be very effective in buffering the volume change of Si during cycling.

• The korean journal of orthodontics
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• v.20 no.1
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• pp.61-86
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• 1990

To study the effect of prostglandin $E_2$ and evening primrose oil on orthodontic tooth movement in rats, one hundred and sixty rats were divided into four groups of 40 rats each. One group, injected with saline on the palate subperiosteally, served as a control group. A second and third group were injected subperiosteally on the palate with $PGE_2$ $10{\mu}g$ and evening primrose oil 10mg respectively. The fourth group was given indomethacin $20{\mu}g/m{\ell}$ orally by water bottle. The maxillary first molar was moved mesially from the incisors using a 50gm force rubber band. In each group at the 1, 2, 3, 5, and 7th day, 4 rats were examined by light microscope, and 4 by electron microscope. The obtained results were as follows: 1. Osteoclastic activity was maximum at the 3rd day in the $PGE_2$ group on the interradicular alveolar bone of the first molar, followed by the evening primrose oil group, control group, and indomethacin group. 2. Root resorption and vacuolar changes were maximum in the $PGE_2$ group. 3. At the 3rd day of the $PGE_2$ group, the osteoclasts showed well developed ruffled borders and clear zones. At the same day, the evening primrose oil group also showed well developed ruffled borders and clear zones, but less than the $PGE_2$ group. 4. At the 3rd and 5th day of the $PGE_2$ group, fibroblasts showed phagocytized fragmented collagen fibers in the cytoplasm. At the 7th day of the $PGE_2$ group, fibroblasts showed collagen fibers forming at the cell membrane surface.

• Elastomers and Composites
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• v.35 no.3
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• pp.205-214
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• 2000

The polyurethane resin was prepared by the reaction of tolylenediisocyanate(TDI) and polypropyleneglycol(PPG). Physical properties of the resin were investigated experimentally. Charging catalyst before TDI-dropping induced the rapid increase of viscosity. On the other hand, charging catalyst after TDI-dropping resulted in mild stability without immoderate generation of heat on reaction. The use of phosphoric acid as catalyst led to low viscosity by restraining side-reaction such as forming of branch-chain, buret reaction and allopanate reaction, but it showed low cross-link density and slow drying. The curing speed was more influenced by structures of molecules rather than NCO/OH ratio. Including PPG 400 over 30 wt % showed excellent adhesive strength due to increase of crosslink density.

• Journal of Fashion Business
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• v.23 no.1
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• pp.37-48
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• 2019

WKSF (Warp-knitted spacer fabrics) knitted using a double Raschel machine is the three-dimensional knit that has vertically connected separate layers in loop structures. Because of its unique structure, the fabric is light, compressible and breathable. Owing to the high production speed, the use of the fabric is increasing in various areas. The purpose of this study is to establish the design process in the utilization of WKSF program and analyze the difference between WKSF and Neoprene as garment materials.. The study on the design related to WKSF has rarely been carried out because of the complexity of WKSF structure and the difficulties encountered in analyzing the structure and thread. Therefore, checking beforehand the simulation results similar to a final knit using the CAD program for WKSF can only enhance the efficiency of the design for the light knits. The conclusion drawn after designing the light knits using the CAD program and analyzing the pros and cons of WKSF through the various property evaluation techniques is as follows. The tension characteristic analysis results indicated that Neoprene specimen has the elastic transformation and resilience, thus behaving like an elastic product such as rubber. By contrast, in the event that clothing and fashion accessories are designed with WKSF, these products are kept in a boxy style fit so that the fabric can be applied flexibly to a curvy body line. In addition, WKSF is good in forming noticeably around a curvy body, because its resistance shear deformation is lower than that of Neoprene.

• Journal of Chest Surgery
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• v.39 no.10 s.267
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• pp.770-774
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• 2006

Background: Continuous air leakage through chest tube after lung surgery may increase pt's hospital stay and lead to many complications including empyema etc. Chemical pleurodesis has frequently been used for prevention of air leakage. Therefore, we performed chemical pleurodesis using diluted fibrin glue in patients with continuous air leak-age and observed the effects and efficiency of treatment. Material and Method: From September, 2001 to August, 2005, 16 patients whose continuous air leakage lasted more than 7 days underwent chemical pleurodesis with diluted fibrin glue. The effects of treatment, complications and recurrences were reviewed. Dissolved fibrinogen 1.0 g and aprotinin 500,000 KIU were mixed in a 50 cc syringe (Mixed solution A). And dissolved thrombin 5,000 IU and Calcium chloride 600 mg were mixed in a 50 cc syringe (Mixed solution B). Cefazolin 1.0 g was mixed in a 50 cc syringe (Mixed solution C). Rubber tube was inserted between the chest tube and the collecting bottle. An inserted rubber tube was positioned 60cm above the patient and forming a loop appearance was done. Mixed solutions A, B and C were injected into the highest rubber tube. Results: Continuous air leakages disappeared in all f6 patients at next day. Chest tubes were removed after 3 days in all patients. Complications were chest pain in 12 patients (75%), leukocytosis in 14 patients (88%), fever and chill in 14 patients (88%). All complications were transient and disappeared without specific treatment. Conclusion: Our findings demonstrated that diluted fibrin glue chemical pleurodesis was effective in patients with continuous air leakage lasting more than 7 days. Diluted fibrin glue chemical pleurodesis had good results with acceptable complications. long term follow-up is necessary to evaluate the accurate effects of treatment and recurrence in a large number of patients.