• Restorative Dentistry and Endodontics
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• 제34권1호
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• pp.51-60
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• 2009

본 연구는 현재 시판 되고 있는 여러 개의 상아질 접착제를 임상 술식에서와 같은 방법으로 사용한 다음 열순환 후 접착계면의 변화를 관찰 비교하고자 했다. 발거 한지 한 달 이내인 대구치 28개의 교합면 상아질 표면에 4종의 상아질 접착제 (OptiBond FL [OP], AdheSE [AD], Clearfil SE Bond [CL], Xeno III [XE]) 중 하나를 적용한 뒤 복합 레진 (Premisa, Kerr) 을 1 mm 두께로 올린 후 광중합 하였다. $4^{\circ}C$ 증류수에서 6일간 보관한 뒤, 치아의 정중선으로부터 수직으로 절단 하여 그 중 절반의 치아에서 2 mm 두께의 시편을 얻은 다음 남은 반쪽의 치아는 10,000회의 열순환을 가한 뒤 ($5^{\circ}-55^{\circ}$, 침지 시간 25초, 대기 시간 5초) 같은 방법으로 2 mm 두께의 시편을 얻었다. 연마한 시편을 24시간 동안 50% ammoniacal silver nitrate solution에 담근 다음 photo-developing solution에서 8시간 동안 환원시켰다. 계면을 가로지르는 5개의 line상에서 wavelength dispersive spectrometry (WDS) detector를 이용하여 주사전상에 있는 원소들의 중량비를 계산하였다. 또한 열순환 전과 후의 시편에서 얻어진 5개의 silver 측정치를 서로 비교하였다. 열순환 전의 접착제층(adhesive layer)에서는 OP에서 가장 적은 silver의 투과가 관찰되었으며 (p < 0.0001), CL, AD, XE 순으로 투과 량이 증가함을 보였다. 혼성층 (Hybrid layer) 에서는 CL의 투과량이 가장 적었다 (p = 0.0039). 열순환 후에 접착제층과 혼성층에서 silver의 투과량은 증가하지는 않았다. Scanning electron microscopy (SEM) 사진을 통하여 각 시편의 접착 계면에서 접착제에 따른 특이적인 silver의 투과상을 관찰할 수 있었다. 전반적으로 OP 와 CL의 접착계면이 열순환 과정 중에도 온전히 유지됨을 볼 수 있었다. 접착 계면에서의 수분 투과 양상은 각 접착제에 따라 다른 형태를 보였으며 열 순환에 의해 유의할 만한 변화를 야기하지는 않았다.

• Journal of Photoscience
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• 제1권1호
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• pp.63-66
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• 1994

Silver chlorobromoiodide cubic seed emulsion was prepared'in the presence of ammonia and phenylcarbamyl gelatin solution. When benzenethiosulfonate sodium salt (BTS) and 4-hydroxy6-methyl-1,3,3a,7-tetraazaindene (TAI), as growth modifiers, were added in the seed emulsion, the silver halide microcrystals were obtained in the forms of cubo-octahedrons, octahedrons, rhombic dodecahedron by variation of pAg value through controlled double jet. The crystal habits and shapes were determined by means of X-ray diffraction (D/MAX BIB, Rigaku) and electron microscopy (JSM-840, JEOL), respectively.

• E2M - 전기 전자와 첨단 소재
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• 제10권7호
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• pp.713-718
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• 1997

Polyaniline free standing films cast from N-methyl-2-pyrrolidinone(NMP) solution, camphorsulfonic acid(HCSA), dodecylbenzensulfonic acid(HDBSA), inorganic matter(carbon black, graphite) and metal(silver) were prepared by processings. The properties of these films such as crystallinity, near-infrared absorption spectra and conductivity were investigated. The HCSA and HDBSA doped polyaniline films cast from m-cresol and chloroform solvents showed the metallic property and high crystallinity, respectively. The value of conductivity in the HCSA doped polyaniline film obtained 180 S/cm. We have obtained the value of conductivity 200 S/cm in the metal(silver) doped polyaniline film, which is higher than that of the HCSA doped polyaniline film. The metal(silver) doped polyaniline film shows good properties as a electromagnetic shielding material.

• 한국분말재료학회지
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• 제15권3호
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• pp.221-226
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• 2008

Silver coated copper composite powders were prepared by electroless plating method by controlling the activation and deposition process variables such as feeding rate of silver ions solution, concentration of reductant and molar ratio of activation solution $(NH_4OH/(NH_4)_2SO_4)$ at room temperature. The characteristics of the product were verified by using a scanning electron microscopy (SEM), X-ray diffraction (XRD) and atomic absorption (A.A.). It is noted that completely cleansing the copper oxide layers and protecting the copper particles surface from hydrolysis were important to obtain high quality Ag-Cu composite powders. The optimum conditions of Ag-Cu composite powder synthesis were $NH_4OH/(NH_4)_2SO_4$ molar ratio 4, concentration of reductant 15g/l and feeding rate of silver ions solution 2 ml/min.

• 한국표면공학회지
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• 제53권4호
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• pp.182-189
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• 2020

Indium tin oxide (ITO) used a transparent electrode of a photoelectric device has a low sheet resistance and a high transmittance. However, ITO is disadvantageous in that the process cost is expensive, and the process time is long. Silver nanowires (AgNWs) transparent electrodes are based on a low cost solution process. In addition, it has attracted attention as a next-generation transparent electrode material that replaces ITO because it has similar electrical and optical characteristic to ITO, it is noted as a. AgNW thin films are mainly produced by spin-coating. However, the spin-coating process has a disadvantage of high material loss. In this study, the material loss was reduced by using about 2~10 ㎕ of AgNW solution on a (25 × 25) ㎟ substrate using the shear-coating method. It was also possible to align AgNWs in the drag direction by dragging the meniscus of the solution. The electro-optical properties of the AgNW thin film were adjusted by changing the experimental parameters that the amount of AgNWs suspension, the gap between the substrate and the blade, and the coating speed. As a result, AgNW thin films with a transmittance of 90.7 % at a wavelength of 550 nm and a sheet resistance of 15 Ω/□ was deposited and exhibited similar properties to similar AgNW transparent electrodes studied by other researchers.

• Restorative Dentistry and Endodontics
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• 제37권1호
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• pp.41-49
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• 2012

Objectives: The internal adaptation of composite restorations with or without resin modified glass ionomer cement (RMGIC) was analyzed non-destructively using Microcomputed tomography (micro-CT). Materials and Methods: Thirty intact human teeth were used. The specimens were divided into 3 groups. In the control group, the cavities were etched with 10% phosphoric acid for 15 sec. Composite resin was filled into the cavity without adhesive. In group 1, light cured glass ionomer cement (GIC, Fuji II LC, GC) was applied as a base. The cavities were then etched, bonded, light cured and filled with composites. In group 2, the cavities were then etched, bonded, light cured and filled with composites without base application. They were immersed in a 25% silver nitrate solution. Micro-CT was performed before and after mechanical loading. One-way ANOVA with Duncan analysis was used to compare the internal adaptation between the groups before or after loading. A paired t-test was used to compare internal adaptation before and after mechanical loading. All statistical inferences were made within the 95% confidence interval. Results: The silver nitrate solution successfully penetrated into the dentinal tubules from the pulp spaces, and infiltrated into the gap between restoration and pulpal floor. Group 2 showed a lower adaptation than the control group and group 1 (p < 0.05). There was no significant difference between the control group and group 1. For all groups, there was a significant difference between before and after mechanical loading (p < 0.05). Conclusions: The internal adaptation before and after loading was better when composites were bonded to tooth using adhesive than composites based with RMGIC.

• 한국재료학회지
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• 제30권3호
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• pp.131-135
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• 2020

Silver nanowire (AgNW) networks have been adopted as a front electrode in Cu(In,Ga)Se2 (CIGS) thin film solar cells due to their low cost and compatibility with the solution process. When an AgNW network is applied to a CIGS thin film solar cell, reflection loss can increase because the CdS layer, with a relatively high refractive index (n ~ 2.5 at 550 nm), is exposed to air. To resolve the issue, we apply solution-processed ZnO nanorods to the AgNW network as an anti-reflective coating. To obtain high performance of the optical and electrical properties of the ZnO nanorod and AgNW network composite, we optimize the process parameters - the spin coating of AgNWs and the concentration of zinc nitrate and hexamethylene tetramine (HMT - to fabricate ZnO nanorods. We verify that 10 mM of zinc nitrate and HMT show the lowest reflectance and 10% cell efficiency increase when applied to CIGS thin film solar cells.

• 한국전기전자재료학회논문지
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• 제34권2호
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• pp.115-120
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• 2021

In this study, composite transparent electrodes were fabricated either from a conductive polymer poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) or silver nanowire (AgNW). Three transparent electrodes such as PEDOT:PSS, PEDOT:PSS and AgNW mixture, and AgNW were fabricated. As for a transparent electrode, measured sheet resistance values were 89.6, 60.6 and 28.6 Ω/sq, and the transmittance values were 80.2, 82.0 and 83.8% while surface roughness (Rq) values were 4.1, 8.1, 20.4 nm for PEDOT:PSS, PEDOT:PSS and AgNW mixture, and AgNW, respectively. To verify the overall performance of these composite electrodes, we applied these electrodes to the top electrode of the solution-processed organic solar cells (OSCs). PEDOT:PSS provided the best performance with a fill factor (FF) of 51.2% and a photoconversion efficiency (PCE) of 2.2%, while traditional metal top electrode OSC provided FF of 60.5% and PCE of 3.1%.

• 자원환경지질
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• 제3권3호
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• pp.177-186
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• 1970

Bupyong lead-silver mine is located at outskirt of Inchon, a harbor city on the Yellow Sea about 40 km due west of Seoul. The geology of the area is composed of gneisses of pre-Cambrian age, rhyolite of Jurassic to Cretaceous age which extruded over the gneisses and late Cretaceous granite. Small diabasic dike is observed only in the underground. The contact plane between overlying rhyolite and underlain gneiss is sinuous and generally pitches about $30^{\circ}{\sim}40^{\circ}$ toward east. Conjugate joints and fissures are well developed in the rhyolite striking generally north-southward. Three ore bodies are being exploited and three more are under prospecting. These ore bodies range from few tons of hundred thousand to million tons in reserve. These ore bodies occur exclusively in the rhyolite along joints as network and/or desseminated type. The lower limit of ore bodies is always delineated at about 20~30m above the gneiss which might be indicative of ore genesis that has not been clearly explained so far. Two hypothesis on ore genesis could, however, be considered: firstly lithologic difference in the rhyolite might be a manifestation of different flows along which ore solution ascended and replaced along joints; secondly diabasic dike has acted as ore bringer since the dike contains considerable amount of silver, lead and zine. Ore minerals are galena and native silver accompanied by pyrite, argentite, pyragyrite and magnetite. It is believed that pyritization took place in advance to main mineralization, and ore deposit is classified as meso- to epi-thermal type.

• Corrosion Science and Technology
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• 제6권6호
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• pp.304-307
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• 2007

As to the reflection electrode of LCD (liquid crystal displays), silver-copper-gold alloy (hereafter, it is called as ACA (Ag98%, Cu1%, Au1%)) is an effective material of which weathering resistance can be improved more compared with pure silver. However, there is a problem that gold remains on the substrate as residues when ACA is etched in cerium ammonium nitrate solution or phosphoric acid. Gold can not be etched in these etchants as readily as the other two alloying elements. Gold residue has actually been removed physically by brushing etc. This procedure causes damage to the display elements. Another etchant of iodine/potassium iodide generally known as one of the gold etchants can not give precise etch pattern because of remarkable difference in etching rates among silver, copper and gold. The purpose of this research is to obtain a practical etchant for ACA alloy. The results are as follows. The cyanogen complex salt of gold generates when cyanide is used as the etchant, in which gold dissolves considerably. Oxygen reduction is important as the cathodic reaction in the dissolution of gold. A new etchant of sodium cyanide / potassium ferricyanide whose cathodic reduction is stronger than oxygen, can give precise etch patterns in ACA alloy swiftly at room temperature.