• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.643-645
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• 2008

Stainless steel 304 and 316 plates were deposited with the multi-layered coatings of titanium film (0.1um) and gold film (1-2um) by an electron beam evaporation method. The XRD patterns of the stainless steel plates modified with the multi-layered coatings showed the crystalline phases of the external gold film and the stainless steel substrate. Surface microstructural morphologies of the stainless steel bipolar plates modified with multi-layered coatings were observed by AFM and FE-SEM images. The external gold films formed on the stainless steel plates showed microstructure of grains of about 100nm diameter. The grain size of the external surface of the stainless steel plates increased with the gold film thickness. The electrical resistance and water contact angle of the stainless steel bipolar plates covered with multi-layered coatings were examined with the thickness of the external gold film.

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.194-196
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• 2005

A series of inorganic-organic hybrid membranes were prepared with a systematic variation of titanium dioxidenanoparticles content. Their liquid uptake, methanol permeability and proton conductivity as a function of inoranic oxide content were investigated. The results obtained show that the inorganic oxide network decreases the proton conductivity and liquid uptake. It is also found that increase in inorganic oxide content leads to decrease of methanol permeability. In terms of the morphology, membranes are homogeneous and exhibit a good adhesion between inorganic domains and the polymer matrix. The properties of the composite membranes are compared with the standard nafion membrane.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.409-411
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• 2005

A series of inorganic-organic hybrid membranes were prepared with a systematic variation of titanium dioxidenanoparticles content. Their water uptake, methanol permeability and proton conductivity as a function of inorganic oxide content were investigated. The results obtained show that the inorganic oxide network decreases the proton conductivity and water swelling. It is also found that increase in inorganic oxide content leads to decrease of methanol permeability. In terms of the morphology, membranes are homogeneous and exhibit a good adhesion between inorganic domains and the polymer matrix. The properties of the composite membranes are compared with the standard nation membrane.

• Membrane Journal
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• v.22 no.1
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• pp.1-7
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• 2012

We make a studyof the hydrogen permeability and chemical stability of $Nb_{56}Ti_{23}Ni_{21}$ metal alloy membrane. For this purpose, we produced the $Nb_{56}Ti_{23}Ni_{21}$ membrane which has 10 mm diameter and 0.5 mm thick, and experiment the hydrogen transport properties under two kinds of feed gas ($H_2$ 100%; $H_2$ 60% + $CO_2$ 40%) at $450^{\circ}C$C with variation of absolute pressure.The maximum hydrogen permeation flux was $5.58mL/min/cm^2$ in the absolute pressure 3 bar under pure hydrogen. And each case of feed gases about gas composition, the permeation fluxes were satisfied with Sievert's law, and the hydrogen permeation flux decreased with decrease of hydrogen partial pressure irrespective of temperature and pressure. After permeation test, we experiment the stability and durability of $Nb_{56}Ti_{23}Ni_{21}$ alloy membrane for carbon dioxide by XRD analysis.

• Journal of Electrochemical Science and Technology
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• v.7 no.4
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• pp.269-276
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• 2016

Carbon-supported ordered Pt-Ti alloy nanoparticles were prepared as a durable and efficient oxygen reduction reaction (ORR) electrocatalyst for polymer electrolyte membrane fuel cells (PEMFCs) via wet chemical reduction of Pt and Ti precursors with heat treatment at $800^{\circ}C$. X-ray diffraction analysis confirmed that the prepared electrocatalysts with Ti precursor molar compositions of 40% (PtTi40) and 25% (PtTi25) had ordered $Pt_3Ti$ and $Pt_8Ti$ structures, respectively. Comparison of the ORR polarization before and after 1500 electrochemical cycles between 0.6 and 1.1 V showed little change in the ORR polarization curve of the electrocatalysts, demonstrating the high stability of the PtTi40 and PtTi25 alloys. Under the same conditions, commercial carbon-supported Pt nanoparticle electrocatalysts exhibited a negative potential shift (10 mV) in the ORR polarization curve after electrochemical cycling, indicating degradation of the ORR activity.

• Journal of Audiology & Otology
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• v.25 no.3
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• pp.159-162
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• 2021

Temporal bone trauma can cause hearing loss and in case of prolonged conductive hearing loss, traumatic ossicular injury should be considered. Separation of the incudostapedial joint is the most common lesion, and stapediovestibular dislocation is relatively rare but can easily cause perilymphatic fistula. Here, we report a very rare case of external stapediovestibular dislocation after trauma, ending up with successful surgical outcome. A 27-year-old man with non-progressive hearing loss on the right side since childhood visited the clinic. Audiogram showed a conductive hearing loss with air-bone gap of 55 dB on the right side. Temporal bone CT revealed the disruption of ossicular chain. An exploratory tympanotomy identified multiple ossicular disruptions including external stapediovestibular dislocation with shiny fibrous membrane sealing the oval window. Ossicular chain reconstruction was performed using the total ossicular replacement prosthesis of titanium. A postoperative audiogram showed a recovery of air-bone gap less than 10 dB. To the best of our knowledge, this is the first case of external long-standing stapediovestibular dislocation, with oval window completely sealed with fibrous membrane, ending up with successful hearing recovery by surgery. This case would help dealing with such condition which can be encountered in the clinic.

• Korean Journal of Audiology
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• v.25 no.3
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• pp.159-162
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• 2021

Temporal bone trauma can cause hearing loss and in case of prolonged conductive hearing loss, traumatic ossicular injury should be considered. Separation of the incudostapedial joint is the most common lesion, and stapediovestibular dislocation is relatively rare but can easily cause perilymphatic fistula. Here, we report a very rare case of external stapediovestibular dislocation after trauma, ending up with successful surgical outcome. A 27-year-old man with non-progressive hearing loss on the right side since childhood visited the clinic. Audiogram showed a conductive hearing loss with air-bone gap of 55 dB on the right side. Temporal bone CT revealed the disruption of ossicular chain. An exploratory tympanotomy identified multiple ossicular disruptions including external stapediovestibular dislocation with shiny fibrous membrane sealing the oval window. Ossicular chain reconstruction was performed using the total ossicular replacement prosthesis of titanium. A postoperative audiogram showed a recovery of air-bone gap less than 10 dB. To the best of our knowledge, this is the first case of external long-standing stapediovestibular dislocation, with oval window completely sealed with fibrous membrane, ending up with successful hearing recovery by surgery. This case would help dealing with such condition which can be encountered in the clinic.

• Journal of Periodontal and Implant Science
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• v.45 no.4
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• pp.128-135
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• 2015

Purpose: The aim of this study was to determine the effect of overlaying titanium mesh (TM) with an adjunctive collagen membrane (CM) for preserving the buccal bone when used in association with immediate implant placement in dogs. Methods: Immediate implant placements were performed in the mesial sockets of the third premolars of five dogs. At one site the TM was attached to the fixture with the aid of its own stabilizers and then covered by a CM (CM group), while the contralateral site received only TM (TM group). Biopsy specimens were retrieved for histologic and histomorphometric analyses after 16 weeks. Results: All samples exhibited pronounced buccal bone resorption, and a high rate of TM exposure was noted (in three and four cases of the five samples in each of the TM and CM groups, respectively). A dense fibrous tissue with little vascularity or cellularity had infiltrated through the pores of the TM irrespective of the presence of a CM. The distances between the fixture platform and the first bone-implant contact and the bone crest did not differ significantly between the TM and CM groups. Conclusions: Our study suggests that the additional use of a CM over TM does not offer added benefit for mucosal healing and buccal bone preservation.

• Journal of Periodontal and Implant Science
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• v.25 no.2
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• pp.341-356
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• 1995

The purpose of this study was to evaluate the effect of demineralized freeze dried bone and demineralized bone gel with guided tissue regeneration treatment around titanium implants with dehisced bony defects and also evaluate space maintaining capacity of demineralized bone gel type and DFDB powder type under e-PTFE membrane. In 3 Beagle dogs, mandibular premolar was extracted and four peri-implant osteotomies were formed for dehiscence. After insertion of implants, the four peri-implant defects were treated as follows. 1) In control group. no graft material and barrier membrane were applied. 2) In experimental group.1, the site was covered only with the e-PTFE membrane. 3) In experimental group 2,received DFDB powder and covered by the e-PTFE membrane. 4) In experimental group 3, demineralized bone gel and e-PTFE membrane were used. By random selection, animals were sacrificed at 4, 8, 12 weeks. The block sectioned specimens were prepared for decalcified histologic evaluation(hematoxylin and eosin staining) and undecalcified histologic evahiation(Von Kossa's and toluidine blue staining) with light microscopy. The results of this study were as follows. 1) In control group, there was a little new bone formation and connective tissue was completely filled in the defect area. 2) Experimental group 1 showed lesser quantity of bone formation as compared to the bone grafted group. Thin vertical growth of new bone formation around implant fixture was shown. 3) Experimental group 2 showed thick bucco-lingual growth of new bone formation and grafted bone particles were almost resorbed in 12 week group. 4) In experimental group 3, most grafted bone particles were not resorbed in 12 week group and thick bucco-lingual bone formation was shown in dehisced defect base area. 5) There was no remarkable differences in space making capacity and new bone formation procedure between demineralized freeze-dried bone powder type and demineralized bone gel type.

• Membrane Journal
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• v.23 no.1
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• pp.61-69
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• 2013

The effect of humic acid (HA), and the roles of microfiltration (MF), PES (polyethersulfone) beads adsorption, and photo-oxidation were investigated in hybrid process of ceramic MF and PES beads loaded with titanium dioxide ($TiO_2$) photocatalyst for advanced drinking water treatment. Those were compared and studied in viewpoints of membrane fouling resistance ($R_f$), permeate flux (J), and total permeate volume ($V_T$). Because membrane fouling increased dramatically as decreasing HA, $R_f$ increased and J decreased, and finally $V_T$ was the highest at 2 mg/L HA. In the experiment to investigate the roles of photo-oxidation and adsorption at humic acid 4 mg/L and 6 mg/L. In both conditions, $R_f$ was the lowest and $V_T$ was the highest in MF + $TiO_2$ + UV process. The average treatment efficiencies of turbidity and dissolved organic matters were the highest in MF + $TiO_2$ + UV process, too.