• Journal of the Korean Society of Safety
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• v.19 no.4 s.68
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• pp.31-35
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• 2004

The A17075/CFRP multi-layered hybrid laminate material consists of the alternating A17075-T6 sheets and carbon/epoxy prepregs of M40 fade. The influence of volume fraction and fiber orientation of A17075/CFRP layer on flexural properties of A17075/CFRP laminate alternating A17075-T6 and carbon/epoxy prepreg was investigated. The results obtained from the experimental analysis are as follows: 1. In the $0^{\circ}$ fiber orientation, the mont of increase of the flexural rigidity was $20.5\%$ at the $26.5\%$ volume fraction and $38.0\%\;at\;the\;35.7\%$ volume fraction compared with the flexural rigidity level(20.0GPa) of the $10\%$ volume fraction of CFRP. 2. In the $\pm45^{\circ}$ fiber orientation the amount of decrease of the flexural rigidity was $23.5\%\;at\;the\;20.0\%$ volume fraction and $31.5\%\;at\;the\;33.3\%$ volume fraction compared with the flexural rigidity level of the $10\%$ volume fraction of CFRP. 3. In the $0^{\circ}$ fiber orientation, the flexural strength was 481.5MPa at the $10\%$ volume fraction of CFRP and 583.8MPa at the $26.5\%$ volume fraction and 653.7MPa at the $35.7\%$ volume faction. 4. In the $\pm45^{\circ}$ fiber orientation, the flexural strength was 354.0MPa at the $20.0\%$ volume fraction of CFRP and 340.5MPa at the $33.3\%$ volume fraction.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.23 no.2
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• pp.80-85
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• 2014

Orthodontic treatment is obviously the first choice to get aligned teeth cause of conservative treatment. But it is impossible to get highly esthetic result only orthodontic treatment in case of peg lateralis, discrepancy tooth size, discolored teeth or fractured teeth. As all treatment does, especially in esthetic treatment it is always required interdisciplinary diagnosis and treatment plan; orthodontics, periodontology, prothetics, implant therapy. As also, the treatment should be maintained long-term treatment with stable and harmonious state by esthetic satisfaction and functional occlusion those who needs various dental care as interdisciplinary treatment. This case is the laminate treatment with the orthodontic treatment on 37 ages/ Female patient who has cross bite at anteriors and premolar area and abrasion on centralis at right maxilla. By orthodontic treatment aligned teeth positions, it makes functional occlusion. As laminate treatment with minimum teeth preparation is able to release anterior esthetics. Follow up check for 2 years has been performed since the final prosthetics delivery to the patient. No sign of relapse, fracture of laminate were detected.

• Composites Research
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• v.28 no.5
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• pp.249-253
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• 2015

This paper reports a study on a method for achieving lightweight thermoplastic laminate composites referred to as tow spreading technology. Thickness of an unspread 12 K carbon fiber tow is reduced by increasing the tow width from 7 mm to 20 mm. The polypropylene (PP) film was used to stabilize and impregnate the spread tow, covering it into a partially consolidated prepreg: 12 K carbon fiber spread tow/PP. Laminates were fabricated from the spread tow prepreg and control laminate composites were produced from unspread tow prepreg consisting of 12 K carbon fiber and PP. The void content, tensile and flexural properties of the composite laminates were investigated. Consequently, the spread tow laminate composite exhibited lower void content and improved mechanical properties.

• Composites Research
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• v.23 no.5
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• pp.22-29
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• 2010

This paper describes the evaluations of tension-compression fatigue characteristics and life for glass fiber/epoxy laminate composite applied to railway bogie to reduce weight. Test samples of tension-compression fatigue were composed of glass fiber/epoxy 4-harness woven laminate composites with different stacking sequence of warp-direction, fill-direction and ${\pm}45^{\circ}$-direction. The tension-compression fatigue test was conducted with stress ratio (R) of -1 and frequency of 5Hz. Goodman diagram were used to evaluate the fatigue characteristics and life of glass fiber/epoxy 4-harness satin woven laminate composite. Anti-buckling jig was designed to prevent buckling of specimen under compression load. The test results showed that the fatigue characteristics of glass fiber/epoxy 4-harness satin woven laminate composite with stacking sequence of warp-direction had a good performance in comparison with that of SM490 used to conventional metal railway bogie.

• Journal of the Korean Vacuum Society
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• v.13 no.4
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• pp.150-156
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• 2004

Boron nitride thin films were deposited on Si(100) substrate by RF (Radio-frequency) UBM (Unbalanced Magnetron) sputtering system. The effect of working pressure and substrate bias voltage on microstructure and compressive stress of boron nitride thin films has been investigated. In high working pressure, the alignment of hBN laminates increased with substrate bias voltage, in low working pressure, however, it was high in low substrate bias voltage. Compressive stress evolution and surface morphology of deposited BN films are closely related with the alignment of hBN laminates. The cBN phase without high compressive stress could be nucleated on hBN thin film by controlling the alignment of hBN laminates.

• The Journal of Advanced Prosthodontics
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• v.6 no.1
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• pp.8-13
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• 2014

PURPOSE. The purpose of this study was to evaluate whether surface treatments affect the translucency of laminate veneers with different shades and thicknesses. MATERIALS AND METHODS. A total of 224 disc-shaped ceramic veneers were prepared from A1, A3, HT (High Translucent) and HO (High Opaque) shades of IPS e.max Press (Ivoclar Vivadent) with 0.5 mm and 1.0 mm thicknesses. The ceramics were divided into four groups for surface treatments. Group C: no surface treatments; Group HF: etched with hydrofluoric acid; Group SB: sandblasted with 50-${\mu}m$ $Al_2O_3$; and Group L; irradiated with an Er;YAG laser. A translucent shade of resin cement (Rely X Veneer, 3M ESPE) was chosen for cementation. The color values of the veneers were measured with a colorimeter and translucency parameter (TP) values were calculated. A three-way ANOVA with interactions for TP values was performed and Bonferroni tests were used when appropriate (${\alpha}=0.05$). RESULTS. There were significant interactions between the surface treatments, ceramic shades and thicknesses (P=.001). For the 0.5-mm-thick specimens there were significant differences after the SB and L treatments. There was no significant difference between the HF and C treatments for any shades or thicknesses (P>.05). For the 1-mm-thick ceramics, there was only a significant difference between the L and C treatments for the HT shade ceramics (P=.01). There were also significant differences between the SB and C treatments except not for the HO shades (P=.768). CONCLUSION. The SB and L treatments caused laminate veneers to become more opaque; however, HF treatment did not affect the TP values. When the laminate veneers were thinner, both the shade of the ceramic and the SB and laser treatments had a greater effect on the TP values.

• Journal of Technologic Dentistry
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• v.39 no.3
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• pp.137-143
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• 2017

Purpose: The purpose of this study is to analyze the fitness of heat - pressed ceramic laminate veneers fabricated using the additive manufacturing. Methods: Impression was replicated by using light body silicone and heavy body silicone on the custom tray, and it was fabricated using Type IV Stone. The test specimens were prepared by using a dental scanner, a laminating veneer using a dental design program, and a specimen with a 3D printer. The control specimens were prepared by the lost wax technique and heat - pressed to fabricate the specimens. The data of the specimens were measured by the RMS value of the internal fitness a using a 3-dimensional measurement program. Results: The Stereolithography laminate veneer group was measured at $78.10(4.09){\mu}m$ and the LWV group was measured at $31.50(5.10){\mu}m$. There is a significant difference between the two groups (p<0.001) Conclusion : Evaluation of fitness laminate veneers was fabricated by additive manufacturing showed the difference statistically significantly and clinically acceptable result.

• Elastomers and Composites
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• v.36 no.3
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• pp.195-200
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• 2001

Ultraviolet photografting of acrylic acid onto low density polyethylene was characterized using XPS and contact angle measurement. Effects of surface modification at LDPE and aluminum on LDPE/Al laminate were also investigated. Contact angle decreased significantly at initial state arid tends to level off with increasing UV irradiation time. The improvement of hydrophilicity was due to the presence of acrylic acid on LDPE surface. Graft of acrylic acid onto LDPE was also identified from O1s/C1s ratios in XPS spectrum. Adhesion strength of LDPE-g-AAc/Al laminate showed about 30 times higher than LDPE/A1 system and it could be attributed to the increase of polarity of LDPE surface. Chemical treatment of Al surface using sulfuric acid/sodium dichromate also increased the adhesion strength of LDPE/Al laminate. Adhesion strength of LDPE/Al laminate decreased significantly under acetic acid.

• Steel and Composite Structures
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• v.18 no.3
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• pp.583-601
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• 2015

In the present study, the combined effects of thermal and mechanical loadings on the interlaminar shear stresses of both moderately thin and thick composite laminated beams are numerically analyzed. The finite element modelling of laminated composite beams and analysis of interlaminar stresses are performed using the commercially available software package MSC NASTRAN/PATRAN. The validity of the finite element analysis (FEA) is demonstrated by comparing the experimental test results obtained due to mechanical loadings under the influence of thermal environment with those derived using the present FEA. Various parametric studies are also performed to investigate the effect of thermal loading on interlaminar stresses generated in symmetric, anti-symmetric, asymmetric, unidirectional, cross-ply, and balanced composite laminated beams of different stacking sequences with identical mechanical loadings and various boundary conditions. It is shown that the elevated thermal environment lead to higher interlaminar shear stresses varying with the stacking sequence, length to thickness ratio, ply orientations under identical mechanical loading and boundary conditions of the composite laminated beams. It is realized that the magnitude of the interlaminar stresses along xz plane is always much higher than those of along yz plane irrespective of the ply-orientation, length to thickness ratios and boundary conditions of the composite laminated beams. It is also observed that the effect of thermal environment on the interlaminar shear stresses in carbon-epoxy fiber reinforced composite laminated beams are increasing in the order of symmetric cross-ply laminate, unidirectional laminate, asymmetric cross-ply laminate and anti-symmetric laminate. The interlaminar shear stresses are higher in thinner composite laminated beams compared to that in thicker composite laminated beams under all environmental temperatures irrespective of the laminate stacking sequence, ply-orientation and boundary conditions.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.284-288
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• 2003

This study was investigated the nondestructive characteristics of the damage caused by low-velocity impact on symmetric cross-ply laminates. These laminates were $[0^{\circ}/90^{\circ}]{_{16s,}}\;{_{24s,}}\;{_{32s,}}\;{_{48s}}$, that is, the thickness was 2, 3, 4 and 6 mm. The impact machine, model 8250 Dynatup Instron, was used a drop-weight type with gravity. The impact velocities used in experiment were 0.75, 0.90, 1.05, 1.20 and 1.35 m/sec. The load and deformation were increased as impact velocity increase. Even if the load increased with laminates thickness in same impact velocity, the deformation decreased. The extensional velocity was a quick as laminate thickness increase in same impact velocity and as impact velocity increase in same laminate thickness. In ultrasonic scans, damaged area was represented an dimmed zone. This is due to the fact that the wave, after having been partially reflected by the defects, has not enough energy to tough the oposite side or to come back from it. The damaged laminate areas were different according to the laminate thickness and the impact velocity. The extensional velocities became lower in if direction and higher in $0^{\circ}$ direction when the size of the defects increases. But, it was difficult to draw any conclusion for the extensional velocities in $45^{\circ}$ direction.