• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.4
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• pp.281-289
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• 2016

Agitation is a secondary process used to increase the PR stripping force on an ITO-glass surface; it is an efficient approach to stripping during production. It activates the stripper to chemically penetrate the PR layer and assists by breaking down the physical bonding forces at the surface. In this study, different stripping tests were conducted by varying the dipping time, the composition, the strip temperature, and the stripper concentration. Optimal PR strip conditions were estimated by using comparative visual inspection of stripped sample surfaces. The stripping process was affected by changes in the moving speeds and the sample positions. It was confirmed that the stripping capability improved at a dilute stripper ratio of 20-40% and a strip temperature of $30-40^{\circ}C$ and within 60 s of strip time.

• The korean journal of orthodontics
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• v.43 no.1
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• pp.29-34
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• 2013

Objective: To examine the prophylactic potential of 3 orthodontic bonding adhesives: Fuji Ortho SC, Illuminate, and Resilience. Methods: Thirty-six Wistar Wag rats were randomly divided into 4 groups consisting of 9 rats each. One of the groups received no treatment and was used as a control. In the other groups, individual bands coated with one of the 3 adhesives were cemented to the lower incisors. Enamel samples were obtained after 6 and 12 weeks and analyzed using scanning electron microscopy in combination with energy dispersive spectrometry. Results: Six weeks after band cementation, no fluoride was found in the enamel of the lower incisors. After 12 weeks, there was no fluoride in the enamel of teeth coated with the Resilience composite. However, in the case of the Illuminate composite and the resin-modified glass ionomer Fuji Ortho SC cement, the depth of fluoride penetration reached $2{\mu}m$ and $4.8-5.7{\mu}m$, respectively. Conclusions: Fluoride ions from orthodontic adhesives can be incorporated into the surface layer of the enamel. Orthodontists may apply orthodontic adhesives, such as the Fuji Ortho SC, to reduce the occurrence of caries during orthodontic treatment with fixed appliances.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.397-400
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• 2006

Most of the civil structures in Korea and abroad have many kinds of damages when they are facing over-loaded traffics, long-term serviceability, and severe environmental conditions. Repair, rehabilitation, and retrofit are important for maintaining the serviceability of structures. In recent year, VES-LMC has been widely used as repair material for bridge deck repair and rehabilitation, because the VES-LMC has a various benefits such as traffic opening after 3 hours of curing, higher durability and bond strength. In case of any structure repaired or rehabilitated with VES-LMC, those were influenced capacity of bond between the base layer of slab and VES-LMC as well as physical properties of each other materials. The capacity of bond depended on purity of interface, micro cracks, curing of VES-LMC and so like. A kind of popular concrete repair technique, High pressure water jetting equipment is extremely efficient at removing damaged concrete. Removing damaged or poor quality concrete from sensitive structures such as bridge, tunnels, multi-story car parking decks and runways, using the high pressure water jetting could remove damaged or poor quality concrete remaining healthy and sound concrete. Accordingly, the purpose of this study is that it was to evaluate effect of hydrodemolition on the bond strength of VES-LMC overlay compared with effects of other method such as breaker, untreated. Also, it was evaluated the effect of surface moisture.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.565-568
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• 2000

This paper describes on the temperature characteristics of a SDB(silicon-wafer direct bonding) SOI(silicon-on-insulator) Hall sensor. Using the buried oxide $SiO_2$ as a dielectrical isolation layer, a SDB SOI Hall sensor without pn junction isolation has been fabricated on the Si/$SiO_2$/Si structure. The Hall voltage and the sensitivity of the implemented SOI Hall sensor show good linearity with respect to the applied magnetic flux density and supplied current. In the temperature range of 25 to $300^{\circ}C$, the shifts of TCO(temperature coefficient of the offset voltage) and TCS(temperature coefficient of the product sensitivity) are less than $\pm 6.7$$\times$$10^{-3}$/$^{\circ}C$ and $\pm 8.2$$\times$$10^{-4}$/$^{\circ}C$respectively. These results indicate that the SDB SOI structure has potential for the development of a silicon Hall sensor with a high-sensitivity and hip high-temperature operation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.29-32
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• 2000

Cerium oxide thin film has been proposed as a buffer layer between the ferroelectric film and the Si substrate in Metal-Ferroelectric-Insulator-Silicon (MFIS ) structures for ferroelectric random access memory (FRAM) applications. In this study, CeO$_2$ thin films were etched with Cl$_2$/Ar gas combination in an inductively coupled plasma (ICP). The highest etch rate of CeO$_2$ film is 230 $\AA$/min at Cl$_2$/(Cl$_2$+Ar) gas mixing ratio of 0.2. This result confirms that CeO$_2$ thin film is dominantly etched by Ar ions bombardment and is assisted by chemical reaction of Cl radicals. The selectivity of CeO$_2$ to YMnO$_3$ was 1.83. As a XPS analysis, the surface of etched CeO$_2$ thin films was existed in Ce-Cl bond by chemical reaction between Ce and Cl. The results of XPS analysis were confirmed by SIMS analysis. The existence of Ce-Cl bonding was proven at 176.15 (a.m.u.).

• Journal of the Korean institute of surface engineering
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• v.26 no.3
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• pp.149-157
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• 1993

In the study of TAB(Tape Automated Bonding)technologies, Cu-Cr sputtered seed layer has been used to improve the adhesion between Polyimide and Cu film and electrical properties. But the Cu electrodeposit on Cu-Cr film had poor adhesion or powder-like form due to the surface Cr oxides on the Cu-Cr film. By means of activating the Cu-Cr film with the oxalic acid and phosphoric acid, the Cu film with the improved adhesion could be coated on the Cu-Cr sputtered film in CuSO4 solution. The etching rate was compared with increasing the Cr content of the sputtered Cu-Cr film, and anodic polarization curve in FeCl3 solution was investigated. With increasing the Cr content, the etching rate was reduced. The clean etching cross section could be obtained with increasing the concentration of FeCl3 solution. But above the 13 w/o Cr content, Cu-Cr sputtered film could not bed etched cleanly only with FeCl3 solution and additives were needed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.456-459
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• 2000

Thin films of vanadium oxide(V$O_x$) have been deposited by r.f. magnetron sputtering from $V_2$$O_5$ prget in gas mixture of argon and oxygen. Crystal structure, surface morphology, chemical composition and bonding properties of films in-situ annealed in $O_2$ ambient with various heat-treatment conditions are characterized through XRD, SEM, AES, RBS and FTIR measurements. The filrns annealed below 200 $^{\circ}C$are amorphous, and those annealed above 30$0^{\circ}C$ are polycrystalline. The growth of grains and the transition of vanadium oxide into the higher oxide have been obsenred with increasing the annealing temperature and time. The increase of O/V ratio with increasing the annealing temperature and time is attributed to the diffusion of oxygen and the partial filling of oxygen vacancies. It is observed that the oxygen atoms located on the V-0 plane of $V_2$$O_5$ layer participate more readily in the oxidation process.

• International Journal of Highway Engineering
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• v.18 no.1
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• pp.85-90
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• 2016

PURPOSES : The objective of this paper is to understand the deterioration phenomenon and causes in the pavement of a ramp area. METHODS : Ramp areas need to be sloped because of the centrifugal force, which depends on the vehicle speed and grade of the ramp area. As a result, vertical and horizontal forces are applied on the pavement surface of the ramp area. Furthermore, the horizontal force depends on the vehicle speed and grade of the ramp area. In order to analyze the pavement structure of a ramp area, a multi-layered elastic analysis program was used to evaluate the weakest link of fatigue cracking deterioration, according to the simultaneously applied vertical and horizontal forces. RESULTS : From case studies related to the bonding conditions between the surface and base layer in a ramp area, it was found that the partially bonded cases resulted in a critical potential of fatigue cracking deterioration, in a comparison of 50%, 70%, and fully bonded cases. CONCLUSIONS : According to the results of the case studies, the pavement structure system should be reinforced by upgrading the material or increasing the thickness compared to the general pavement areas, in order to provide a performance life similar to the mainline pavements in the ramp areas.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.29 no.3
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• pp.26-33
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• 1997

The bacterial celluloses are very different in its physical, chemical and morphological structures compared to wood cellulose. These fibers have many unique properties that are potentially and commercially beneficial. This study was aimed to elucidate the production of bacterial celluloses and to improve their physical properties by chemical pretreatment. Bacterial celluloses produced by static culture had gel-like pellicle structure. The pellicle thickness was increased with the increasing time, and its layer was about 1.8cm after one-month incubation. The pellicles extruded from the cells of Acetobacter had a non-crystalline structure during initial growing stages, gradually getting crystaliyzed with the incubation time elapse, and eventually fumed to the cellulose I crystals. Young＇s modulus of bacterial cellulose sheet was increased with increasing NaOH concentration, and resulted in the highest at 5% NaOH concentration. Similar results with NaClO3 pretreatment can be observed. Too concentrated alkali solutions induced the destruction of cellulose fibrils and changed the mechanical properties of the sheets. These alkaline pretreatment have removed non-cellulosic components(NCC) from the bacterial cellulose, and enhanced inter-abrillar bonding by direct close contact among cellulosic fibrils.

• Korean Journal of Materials Research
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• v.6 no.4
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• pp.379-387
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• 1996

본 연구에서는 GaAs 소자제작 및 epi-layer 성장 공정에 있어 이용되어지는 HCI, H3PO4, 탈이온수(de-ionized water:DIW)를 통한 습식제정후 공기중 노출에 따른 오염을 최소화하여 표면상태 변화를 진성적(intrinsic)으로 관찰하고자 모든 세정처리를 아르곤 가스(argon gas)로 분위기가 유지되는 glove box에서 수행하였으며, 표면조성 및 결합상태 변화에 대한 관찰은 X-선 광전자 분광기(X-ray photoelectron spectroscopy)를 통해 이루어졌다. 고진공하에서 GaAs를 벽개하여 관찰함으로써 Ga이 대기중 산소이온과 우선적으로 결합함을 알 수 있었고, 이런 GaAs 표면의 반응성에 대한 고찰을 바탕으로 습식세정에 따른 화학반응 기구가 제시 되어졌다. HCI 및 H3PO4/DIW/HCI처리후 CI-이온의 Ga 이온과의 반응에 의한 Ga-CI결합의 형성과 As 산화물의 높은 용해도에 따른 As 산화물의 완전한 제거 및 식각전 초기(bare)GaAsvyaus에 존재하는 원소(elemental)As 상태의 식각후 잔류가 관찰되어졌다. 또 HCI, H3PO4/DIW/HCI 처리하고 DIW로 세척후 표면상태 변화를 관찰한 결과, DIW처리에 의해 elemental As 상태가 증가함을 알 수 있었다.