• The Journal of the Korean dental association
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• v.53 no.11
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• pp.804-816
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• 2015

PURPOSE: The aim of this study was to evaluate the influence of the oxide layer removal process in the Co-Cr-Mo (CCM) abutment after casting procedure on the prosthesis settlement and screw stability. MATERIALS AND METHODS: CCM abutments of four different interface conditions (CCM-M; machined, CCM-O; oxide layer formed, CCM-B; blasted, CCM-P; polished after blasted) and gold abutment (Gold-C; Cast with type III Gold alloy) were used. The initial settling values of abutments were evaluated according to the difference of implant-abutment length when the tightening torques were applied at 5 Ncm and 30 Ncm, and the settling values of abutments caused by loading were evaluated according to the difference of implant-abutment length before and after loading with 250 N, 100000 cycle. The loss ratios of removal torque for abutment screws were evaluated according to the difference in value of removal torques under 30 Ncm tightening torque applied before and after cyclic loading. RESULTS: The CCM-P and CCM-B group showed a higher initial settling value compared with the Gold-C group (P<.05), while the Gold-C group showed the highest settling values caused by loading (P<.05) and no significant differences were observed for between CCM groups (P>.05). The loss ratio of removal torque values for the CCM-B, CCM-P groups did not differ significantly from that of the Gold-C group (P>.05). CONCLUSION: Even though the oxide layer was removed by different methods, CCM abutment with internal conical connection structure showed lower abutment settling and similar screw loosening after cyclic loading compared with gold abutment.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.5
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• pp.341-344
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• 2018

In order to achieve a high efficiency for the silicon solar cell, a passivation characteristic that minimizes the electrical loss at a silicon interface is required. In this paper, we evaluated the applicability of the oxide film formed by ozone for the tunnel silicon oxide film. To this end, we fabricated the silicon oxide film by changing the condition of ozone oxidation and compared the characteristics with the oxide film formed by the existing nitric acid solution. The ozone oxidation was formed in the temperature range of $300{\sim}500^{\circ}C$ at an ozone concentration of 17.5 wt%, and the passivation characteristics were compared. Compared to the silicon oxide film formed by nitric acid oxidation, implied open circuit voltage (iVoc) was improved by ~20 mV in the ozone oxidation and the ozone oxidation after the nitric acid pretreatment was improved by ~30 mV.

• YAKHAK HOEJI
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• v.19 no.4
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• pp.219-226
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• 1975

Physical and chemical properties on the aging inhibition mechanism of hydrous aluminum oxide were studied by means of dehydration velocity, activation energy, DTA, TGA, IR spectra, X-ray diffraction and TMA. During aging, changes may occur in the hydrous aluminum oxide structure which results in a loss of acid reactivity and in crystal formation to the hydrated hydrous alumina. The results obtained from the X-ray diffraction pattern and DTA, TGA thermogram studies showed that the aging product stabilized with either sorbitol or mannitol was hydrous aluminum oxide ($Al_{2}O_{3}{\cdot}xH_{2}O$) but the aging product not stabilized with either sorbitol or mannitol product not stabilized was hydrated hydrous aluminum oxide $Al_{2}O_{3}{\cdot}xH_{2}O{\cdot}yH_{2}O$. The activation energy of dehydration of the hydrous almina was about 17 Kcal. mol$^{1}$ deg$^{-1}$ which was observed a little less than that of 22 kcal.mol.$^{-1}$ deg.$^{-1}$ of or mannitol, the inhibition mechanism in the aging process from oxide is assumed to prevent the formation of the hydrated hydrous aluminum oxide and the aging process is thought of as analogous to the polymorphic transformations which occur as a system converts to its most stable state.

• Macromolecular Research
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• v.10 no.2
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• pp.85-90
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• 2002

Poly (ethylene oxide)/polylatide/poly(ethylene oxide) (PEO/PL/PEO) tri-block copolymers, which each block is connected by ester bond, were synthesized by coupling reaction of PL with PEO in the presence of pyridine. PL/PEO/PL tri-block copolymer was synthesized by ring opening polymerization of L-lactide initiated by PEO in the presence of stannous octoate. Degradation behavior of the copolymers was investigated in a pH 7.4 phosphate buffer saline (PBS) at 37$\pm$1 $^{\circ}C$. Gel permeation chromatography (GPC) and $^1$H-nuclear magnetic resonance (NMR) were used to monitor the change of mass loss, molecular weight and composition of copolymers. In hydrolytic degradation, the PEO/PL/PEO tri-block copolymer with high PEO contents affected the increase of its mass loss, and resulted in the decrease of its molecular weight as well as PEO composition. However, when PL/PEO/PL and PEO/PL/PEO tri-block copolymers had similar PEO contents, PEO/PL/PEO decreased faster in molecular weight and PEO composition than PL/PEO/PL.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.139-142
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• 2009

In this study, the performance degradation of SOFC single cell caused by the delamination between a cathode and an electrolyte is investigated. As the delamination rate increases, the voltage sharply decreases due to the decrease of reaction sites and losses increase. The current is concentrated to the intact area so that the current density is increased and the ohmic loss and the activation loss become higher. Most part of loss is due to the ohmc loss of electrolyte.

• ETRI Journal
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• v.30 no.6
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• pp.833-843
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• 2008

The effect of forward and reverse electrostatic discharge (ESD) on the electro-optical characteristics of oxide vertical-cavity surface-emitting lasers is investigated using a human body model for the purpose of understanding degradation behavior. Forward ESD-induced degradation is complicated, showing three degradation phases depending on ESD voltage, while reverse ESD-induced degradation is relatively simple, exhibiting two phases of degradation divided by a sudden distinctive change in electro-optical characteristics. We demonstrate that the increase in the threshold current is mainly due to the increase in leakage current, nonradiative recombination current, and optical loss. The decrease in the slope efficiency is mainly due to the increase in optical loss.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.11a
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• pp.93-96
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• 2000

In this study, we investigated the electromagnetic properties of Mn-Zn ferrite doped with rare earth oxide (Dy$_2$O$_3$, Er$_2$O$_3$). The main composition is 52mo1% $\alpha$-Fe$_2$O$_3$, 25mo1% Mn$_3$O$_4$23mo1% ZnO and doped with them(0.05wt%~0.25wt%, step:0.05wt%). An experimental process has advanced by conventional ferrimagnetism manufacturing that was prepared by standard ceramic techniques. The XRD pattern of all doped sample were observed spinel and secondary phase. The density of sample were measured nearly constant value. As increased the additive, resistivity, initial permeability and real component of the series complex permeability increased with setting limits each other. In case of Mn-Zn ferrite excess doped with them, resistivity, initial permeability and real component of the series complex permeability decreased and magnetic loss increased in proportion to increasing the additive.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.549-552
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• 2002

$(SrBi_2Nb_2O_9)_{0.5}-(Bi_3TiNbO_9)_{0.5}$ ceramics were fabricated by the mixed-oxide method, and the structural and electrical properties with variation of ball-milling time were investigated. All SBN-BTN specimens showed the typical polycrystalline X-ray diffraction patterns without the presence of the second phase. The SBN-BTN specimen sintered at $1200^{\circ}C$ and ball-milled for 168h showed the average grain size of $16{\mu}m$. The dielectric constant and dielectric loss of the SBN-BTN specimen sintered at $1150^{\circ}C$ and ball-mill for 72h were 225, 0.4% at 1KHz, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.315-316
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• 2005

This paper describes the AC accelerated ageing characteristics of zinc oxide varistors for the station class lightning surge arresters. ZnO varistors whose rated voltage were 3.27kV, 4.00kV, and 6.00kV were manufactured with general ceramic production methods. The power loss of sample A varistors rapidly increased and eventually showing the thermal run-away, but sample B and sample C varistors exhibited negative creep phenomena in power losses during the test.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.7
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• pp.569-572
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• 2003

In this study, we evaluated the dilute HF cleaning to reduce residual defects made by metal CMP process. The purpose of this test is to observe the existence of barrier metal damage during DHF cleaning on condition that it should not affect metal thin film reliability, so we will get rid of slurry residual particles as a main defect of the metal CMP process for the better yield. In-line defect data showed us that slurry residual particles were removed by DHF application. The HF rinse significantly reduced metal contamination levels and surface roughness. The best effect by additional oxide loss was discovered when Dilute HF condition is 10".