• Journal of the Korean Wood Science and Technology
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• 제40권5호
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• pp.343-351
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• 2012

A large diameter roundwood is an important element of Korean traditional buildings, Hanok, and is hard to be dried without surface cracks. Four different pretreatments, such as pre-cracking, oil heating, kerfing-oil heating and PEG impregnation, were investigated for reducing the surface cracks of large-diameter roundwood specimens during heat treatment. The roundwood specimens of pre-cracking, oil heating and kerfing-oil heating showed surface cracks during pretreatment, but that of PEG impregnation did not. It was confirmed that kerfing reduced the total crack width. Among the four pretreatments and control only the PEG impregnation roundwood specimen had no crack on both outer and inner surfaces after heat treatment. The PEG impregnation specimen shrank only 1.6% in the tangential direction while the pre-cracking did 8.0%.

• Bulletin of the Korean Chemical Society
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• 제34권2호
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• pp.421-425
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• 2013

The effect of pretreatment on indium-tin oxide (ITO) electrodes has been rarely studied, although that on metal and carbon electrodes has been enormously done. The electrochemical and surface properties of ITO electrodes are investigated after 6 different pretreatments. The electrochemical behaviors for oxygen reduction, $Ru(NH_3){_6}^{3+}$ reduction, $Fe(CN){_6}^{3-}$ reduction, and p-hydroquinone oxidation are compared, and the surface roughness, hydrophilicity, and surface chemical composition are also compared. Oxygen reduction, $Fe(CN){_6}^{3-}$ reduction, and p-hydroquinone oxidation are highly affected by the type of the pretreatment, whereas $Ru(NH_3){_6}^{3+}$ reduction is almost independent of it. Interestingly, oxygen reduction is significantly suppressed by the treatment in an HCl solution. The changes in surface roughness and composition are not high after each pretreatment, but the change in contact angle is substantial in some pretreatments.

• Journal of Periodontal and Implant Science
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• 제42권3호
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• pp.95-104
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• 2012

Purpose: The purpose of this study was to determine whether increasing the Ti6Al4V surface oxide negative charge through heat ($600^{\circ}C$) or radiofrequency plasma glow discharge (RFGD) pretreatment, with or without a subsequent coating with fibronectin, stimulated osteoblast gene marker expression in the MC3T3 osteoprogenitor cell line. Methods: Quantitative real-time polymerase chain reaction was used to measure changes over time in the mRNA levels for osteoblast gene markers, including alkaline phosphatase, bone sialoprotein, collagen type I (${\alpha}1$), osteocalcin, osteopontin and parathyroid hormone-related peptide (PTH-rP), and the osteoblast precursor genes Runx2 and osterix. Results: Osteoprogenitors began to differentiate earlier on disks that were pretreated with heat or RFGD. The pretreatments increased gene marker expression in the absence of a fibronectin coating. However, pretreatments increased osteoblast gene expression for fibronectin-coated disks more than uncoated disks, suggesting a surface oxide-mediated specific enhancement of fibronectin's bioactivity. Heat pretreatment had greater effects on the mRNA expression of genes for PTH-rP, alkaline phosphatase and osteocalcin while RFGD pretreatment had greater effects on osteopontin and bone sialoprotein gene expression. Conclusions: The results suggest that heat and RFGD pretreatments of the Ti6Al4V surface oxide stimulated osteoblast differentiation through an enhancement of (a) coated fibronectin's bioactivity and (b) the bioactivities of other serum or matrix proteins. The quantitative differences in the effects of the two pretreatments on osteoblast gene marker expression may have arisen from the unique physico-chemical characteristics of each resultant oxide surface. Therefore, engineering the Ti6Al4V surface oxide to become more negatively charged can be used to accelerate osteoblast differentiation through fibronectin-dependent and independent mechanisms.

• Korean Membrane Journal
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• 제1권1호
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• pp.43-49
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• 1999

Separation of soluble oil was investigated during filtration of cutting oil emulsion using various commercial ultrafiltration membranes. The surface properties of membranes used were hydrophilic hydrophobic and modified surfaces by various surfactant pretreatments. Conditions varied include stirring speed transmeembrane pressure membrane type and surfactant type for pretreatment. The results give some indication of mechanisms occurring at the membrane surface. Surfactant pretreatments significantly improved water flux and UF flux of hydrophilic regenerated cellulose(up to 2.4x for YM100) and hydrophobic polysulfone (up to 2.2x for PTHK) membranes depending on surfactant type and operating conditions. The UF flux enhancement was attributed to membrane swelling and reduction of interfacial surface tension between oil droplets and membrane surface. unexpectedly the hydrophilic membranes revealed greater flux enhancement than the hydrophobic membranes. The results also showed a greater improvement in UF flux at lower operating pressure.

• Journal of the Korean Wood Science and Technology
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• 제48권3호
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• pp.345-363
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• 2020

본 연구는 배할 및 인사이징 전처리가 횡단면 크기 150 mm 이하 삼나무와 낙엽송 수심재의 고온건조 특성에 미치는 영향을 확인하기 위해 수행되었다. 그 결과, 전처리는 표면할렬과 수축률에 대하여 유의한 차이를 나타내었다. 배할처리는 표면할렬 발생을 줄이기 위한 전처리로서 적합하였으나, 인사이징은 재면의 자상이 서로 연결됨으로써 표면할렬로 전환되는 현상을 야기하기 때문에 전처리로서 적합하지 않았다. 수축률은 전처리 조건에 따라 건조 후 최종함수율이 인사이징, 배할, 배할-인사이징 순으로 감소되는 경향을 나타냄으로써 유의한 결과를 나타내었다. 뒤틀림은 미성숙재의 수축이방성보다 목리각도가 더 크게 영향을 주었으며, 전처리의 영향은 없었다.

• 한국재료학회지
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• 제14권3호
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• pp.203-210
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• 2004

Effects of various pretreatments on the adhesion of copper-coated polymer films were investigated. Copper-coated polymer films were prepared by an electron cyclotron resonance-metal organic chemical vapor deposition (ECR-MOCVD) coupled with a DC bias system at room temperature. PET(polyethylene terephthalate) film was employed as a substrate material and it was pretreated by industrially feasible methods such as chromic acid, sand-blasting, oxygen plasma and ion-implantation treatment. Surface characterization of the copper-coated polymer film was carried out by AFM(Atomic Force Microscopy) and FESEM(Field Emission Scanning Electron Microscopy). Surface energy was calculated by based on the value of the contact angle measured. The adhesion of copper/PET films was determined by a pull-off test according to ASTM D-5179. It was found that suitable pretreatment of the PET substrate was required for obtaining good adhesion property between copper films and the substrate. In this study the highest adhesion was observed in sand-blasting, and then followed by those of acid and oxygen plasma treatment. However, the effect of surface energy was insignificant in our experimental range. This is probably due to compensating the difference in surface energy from various pretreatments by exposing substrate to ECR plasma for 5 min or longer at the early stage of the copper deposition. Therefore, it can be concluded that surface roughness of the polymer substrate plays an important role to determine the adhesion of copper-coated polymer for the deposition of copper by ECR-MOCVD.

• Restorative Dentistry and Endodontics
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• 제39권1호
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• pp.12-16
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• 2014

Objectives: Extensively destroyed teeth are commonly restored with composite resin before cavity preparation for indirect restorations. The longevity of the restoration can be related to the proper bonding of the resin cement to the composite. This study aimed to evaluate the microshear bond strength of two self-adhesive resin cements to composite resin. Material and Methods: Composite discs were subject to one of six different surface pretreatments: none (control), 35% phosphoric acid etching for 30 seconds (PA), application of silane (silane), PA + silane, PA + adhesive, or PA + silane + adhesive (n = 6). A silicone mold containing a cylindrical orifice ($1mm^2$ diameter) was placed over the composite resin. RelyX Unicem (3M ESPE) or BisCem (Bisco Inc.) self-adhesive resin cement was inserted into the orifices and light-cured. Self-adhesive cement cylinders were submitted to shear loading. Data were analyzed by two-way ANOVA and Tukey's test (p < 0.05). Results: Independent of the cement used, the PA + Silane + Adhesive group showed higher microshear bond strength than those of the PA and PA + Silane groups. There was no difference among the other treatments. Unicem presented higher bond strength than BisCem for all experimental conditions. Conclusions: Pretreatments of the composite resin surface might have an effect on the bond strength of self-adhesive resin cements to this substrate.

• Restorative Dentistry and Endodontics
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• 제45권3호
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• pp.36.1-36.10
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• 2020

Objectives: This study aims to assess the effect of universal adhesives pretreatment on the bond strength of resin-modified glass ionomer cement to dentin. Materials and Methods: Fifty caries-free human third molars were employed. The teeth were randomly assigned into five groups (n = 10) based on dentin surface pretreatments: Single Bond Universal (3M Oral Care), Gluma Bond Universal (Heraeus Kulzer), Prime&Bond Elect (Dentsply), Cavity Conditioner (GC) and control (no surface treatment). After Fuji II LC (GC) was bonded to the dentin surfaces, the specimens were stored for 7 days at 37℃. The specimens were segmented into microspecimens, and the microspecimens were subjugated to microtensile bond strength testing (1.0 mm/min). The modes of failure analyzed using a stereomicroscope and scanning electron microscopy. Data were statistically analyzed with one-way analysis of variance and Duncan tests (p = 0.05). Results: The surface pretreatments with the universal adhesives and conditioner increased the bond strength of Fuji II LC to dentin (p < 0.05). Single Bond Universal and Gluma Bond Universal provided higher bond strength to Fuji II LC than Cavity Conditioner (p < 0.05). The bond strengths obtained from Prime&Bond Elect and Cavity Conditioner were not statistically different (p > 0.05). Conclusions: The universal adhesives and polyacrylic acid conditioner could increase the bond strength of resin-modified glass ionomer cement (RMGIC) to dentin. The use of universal adhesives before the application of RMGIC may be more beneficial in improving bond strength.

• 대한치과보철학회지
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• 제45권5호
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• pp.621-632
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• 2007

Statement of problem: The failure of adhesion between the resilient denture liner and the denture base is a serious problem in clinic. Purpose: The purpose of this study was to evaluate the effect of denture base resin surface pretreatments (mechanical and/or chemical) on the tensile bond strength between a resilient liner and processed denture resin. Material and method. Acrylic-based resilient liners (Soft liner; GC co., Japan & Coe-Soft; GC America Inc. USA) and silicone-based resilient liners (Mucosoft, Parkell Inc., USA & Dentusil; Bosworth co., USA) were used. Specimens in each soft lining material were divided two groups with or without mechanical pretreatment. Each denture base specimen received 1 of 4 chemical pretreatments including: (1) no treatment, (2) 30-s acetone treatment, (3) 15-s methylene chloride treatment, (4) 180-s methyl methacrylate treatment. All specimens were thermocycled and placed under tension until failure in a universal testing machine. Results: 1. Silicone-based resilient liners exhibited significantly higher tensile bond strengths than acrylic-based resilient liners (P<.05). 2. Grinding the denture base resin improved tensile bond strengths of silicone-based resilient liners, but reduced tensile bond strengths of acrylic-based resilient liners (P<.05). 3. In acrylic-based resilient liners, treating with acetone significantly increased the bond strength of Soft liner and treating with methyl methacrylate significantly increased the bond strength of Coe-Soft (P<.05). However they were not effective compared to silicone-based resilient liner. 4. In silicone-based resilient liners, treating with all chemical etchants significantly increased the bond strength of Mucosoft to denture base, and treating with methylene chloride and methyl methacrylate increased the bond strength of Dentusil to denture base (P<.05). Conclusion: Although chemical and mechanical pretreatments were not effective on tensile bond strength of acrylic-based resilent liner to denture base, treating the denture base resin surface with appropriate chemical etchants after mechanical pretreatment significantly increased the tensile bond strength of silicone-based resilient liner to denture base.

• The Journal of Advanced Prosthodontics
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• 제6권6호
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• pp.434-443
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• 2014

PURPOSE. The purpose of this study was to evaluate and compare the effects of different surface pretreatment techniques on the surface roughness and shear bond strength of a new self-adhering flowable composite resin for use with lithium disilicate-reinforced CAD/CAM ceramic material. MATERIALS AND METHODS. A total of one hundred thirty lithium disilicate CAD/CAM ceramic plates with dimensions of $6mm{\times}4mm$ and 3 mm thick were prepared. Specimens were then assigned into five groups (n=26) as follows: untreated control, coating with $30{\mu}m$ silica oxide particles ($Cojet^{TM}$ Sand), 9.6% hydrofluoric acid etching, Er:YAG laser irradiation, and grinding with a high-speed fine diamond bur. A self-adhering flowable composite resin (Vertise Flow) was applied onto the pre-treated ceramic plates using the Ultradent shear bond Teflon mold system. Surface roughness was measured by atomic force microscopy. Shear bond strength test were performed using a universal testing machine at a crosshead speed of 1 mm/min. Surface roughness data were analyzed by one-way ANOVA and the Tukey HSD tests. Shear bond strength test values were analyzed by Kruskal-Wallis and Mann-Whitney U tests at ${\alpha}=.05$. RESULTS. Hydrofluoric acid etching and grinding with high-speed fine diamond bur produced significantly higher surface roughness than the other pretreatment groups (P<.05). Hydrofluoric acid etching and silica coating yielded the highest shear bond strength values (P<.001). CONCLUSION. Self-adhering flowable composite resin used as repair composite resin exhibited very low bond strength irrespective of the surface pretreatments used.