• Restorative Dentistry and Endodontics
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• 제39권1호
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• pp.12-16
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• 2014

Objectives: Extensively destroyed teeth are commonly restored with composite resin before cavity preparation for indirect restorations. The longevity of the restoration can be related to the proper bonding of the resin cement to the composite. This study aimed to evaluate the microshear bond strength of two self-adhesive resin cements to composite resin. Material and Methods: Composite discs were subject to one of six different surface pretreatments: none (control), 35% phosphoric acid etching for 30 seconds (PA), application of silane (silane), PA + silane, PA + adhesive, or PA + silane + adhesive (n = 6). A silicone mold containing a cylindrical orifice ($1mm^2$ diameter) was placed over the composite resin. RelyX Unicem (3M ESPE) or BisCem (Bisco Inc.) self-adhesive resin cement was inserted into the orifices and light-cured. Self-adhesive cement cylinders were submitted to shear loading. Data were analyzed by two-way ANOVA and Tukey's test (p < 0.05). Results: Independent of the cement used, the PA + Silane + Adhesive group showed higher microshear bond strength than those of the PA and PA + Silane groups. There was no difference among the other treatments. Unicem presented higher bond strength than BisCem for all experimental conditions. Conclusions: Pretreatments of the composite resin surface might have an effect on the bond strength of self-adhesive resin cements to this substrate.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권5호
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• pp.319-325
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• 1999

Direct current(d.c.)leakage current voltage characteristics of radio-frequencymagnetron sputtered BaTa\sub 2\O\sub 6\ film capacitors with aluminum(A1) top and indium tin oxide (ITO) bottom electrodes have been investigatedas a function of applied field and temperature. In order to study surfacetreatment effect on the electrical characteristics of as-deposited film weperformed exposure of oxygen plasma on $BaTa_2O_6$ surface. d. c.current-voltage (I-V), bipolar pulse charge-voltage (Q-V), d. c. current-time (I-t) andcapacitance-frequency (C-f) analysis were performed on films. All ofthe films exhibita low leakage current, a high breakdown field strength (3MV/cm-4.5MV/cm), and high dielectric constant (20-30). From the temperature dependence of leakage current,we can conclude that the dominant conduction mechanism is ascribed toSchottky emission at high electric field (>1MV/cm) and hopping conduction at lowelectric field (<1MV/cm). According to our results, the oxide plasma surfacetreatmenton as-deposited $BaTa_2O_6$ resulted in lowering interfacebarrier height and thus, leakage current when a negative voltage applied to the A1 electrode. This can be explained by reduction of surface contamination via etching surface and filling defects such as oxygen vacancies.

• 한국표면공학회지
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• 제42권4호
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• pp.157-160
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• 2009

Many fundamental studies have been carried out regarding waste water and hazardous gas treatments technologies using the photolysis effect of $TiO_2$. However, a permanent use of $TiO_2$ particles immobilized using organic or organic-inorganic binders is impossible. In this study, Ni-$TiO_2$ composite coating was produced by electroless plating to trap $TiO_2$ particles in the Ni coating layer. The electroless plating was performed in the bath solutions with three different concentrations of $TiO_2$ particles : 10 g/l, 20 g/l, and 40 g/l. The surface and photolytic characteristics of the coating layer was investigated by the use of SEM, a scratch tester, and an UV-Visible spectrophotometer. The results showed that the amounts of immobilized $TiO_2$ particles and the photolytic rate of the coating increased with the initial content of $TiO_2$ particles in the electroless bath. In addition, the photolytic rate of the Ni-$TiO_2$ composite coating was remarkably promoted by etching process in 10% HCl solution.

• 한국포장학회지
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• 제29권3호
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• pp.223-228
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• 2023

Sustainable energy supplies without the recharging and replacement of the charge storage device have become increasingly important. Among various energy harvesters, the triboelectric nanogenerator (TENG) has attracted considerable attention due to its high instantaneous output power, broad selection of available materials, eco-friendly and inexpensive fabrication process, and various working modes customized for target applications. In this study, the amount of voltage and current generated was measured by applying the PSD profile random vibration test of the electronic vibration tester and ISTA 3A according to the time of Anodized Aluminum Oxide (AAO) pore widening of the manufactured TENG device Teflon and AAO. The discharge and charging tests of the integrated module during the random simulated transport environment and the recognition distance of RFID were measured while agricultural products (onion) were loaded into the returnable folding plastic box. As a result, it was found that AAO alumina etching processing time to maximize TENG performance was optimal at 31 min in terms of voltage and current generation, and the integrated module applied with the TENG module showed a charging effect even during the continuous use of RFID, so the voltage was kept constant without discharge. In addition, the RFID recognition distance of the integrated module was measured as a maximum of 1.4 m. Therefore, it was found that the surface condition of AAO, a TENG element, has a great influence on the power generation of the integrated module, and due to the characteristics of TENG, the power generation increases as the surface dries, so it is judged that the power generation can be increased if the surface drying treatment (ozone treatment, etc.) of AAO is applied in the future.

• Journal of Oral Medicine and Pain
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• 제21권2호
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• pp.207-224
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• 1996

This study was designed to determine the most effective concentration of fluoride and energy density of laser irradiation for the anticarious effect. For this study surface hardness in enamel was measured before and after irradiation with pulsed Nd;YAG laser and the topical application of fluoride. Of the permanent mandibular anterior hovine teeth, healthy, carious free ones were used. Three hundred specimens were made. Specimens within 25~45 Vickers hardness numbers were assigned to 20 control and experimental stoops ; each containing 15 specimens. After forming artificial carious lesions, 10 J/$\textrm{cm}^2$, 20 J/$\textrm{cm}^2$, and 30 J/$\textrm{cm}^2$ energies were irradiated on the enamel surface of each experimental group. Also NaF, NH4F, Elmex gel(amine fluoride) and APF gel fluoride compounds were applied topically. Next, all the specimens were placed into the pH circulatory procedures for eight days. Vickers hardness numbers were measured using a microhardness tester. Surface changes of the enamel were observed using an scanning electron microscope. The comparative ana1ysis yielded the following results : 1. The reduction of surface hardness of the enamel surface was less in all groups with fluoride application than in the group without fluoride application. 2. The APF gel croup with 10 J/$\textrm{cm}^2$ irradiation showed the lowest reduction of surface hardness. 3. The reduction of surface hardness of the enamel surface in the group of laser irradiation without fluoride application not showed any significant difference according to the energy density of the laser. 4. Under the scanning electron microscope, in enamel irradiated with 10J/$\textrm{cm}^2$ showed appearance similar to acid etching surface. In enamel irradiated with 20 J/$\textrm{cm}^2$, line enamel crack was detected. In enamel irradiated with 30j/$\textrm{cm}^2$, severe enamel crack and fusion of enamel were detected. These results suggest that one could obtain the best anticariogenic effects without damage to teeth in the group of application of APF gel after laser irradiation with 10 J/$\textrm{cm}^2$.

• 자원리싸이클링
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• 제17권2호
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• pp.36-45
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• 2008

실리콘 웨이퍼 에칭공정에서 발생하는 폐산을 스테인리스 스틸 산세공정에서 재활용하고자 이를 이용한 산세 거동을 조사하였다. 폐산 원액은 $19.6g/L^{-1}$ 실리콘을 함유한 불산, 질산 및 초산의 혼산이었으며 침전법에 의한 실리콘 제거 전후 폐산들을 이용하여 304 스테인레스 스틸 표면 산화막의 제거 시 측정된 open circuit potential(OCP) 변화 거동은 매우 상이하였다. 폐산 원액을 사용한 경우에는 OCP가 높고 연속적인 변화를 보이는데 비하여 실리콘 제거 공정에서 얻어진 용액의 경우에는 불연속적인 OCP변화와 전위요동현상이 나타났다. 이러한 거동의 차이는 표면 부동태막의 형성 및 제거와 공식이 발생하는 정도의 차이에 기인하는 것으로 생각되며, 실리콘 제거 공정에서 산도가 낮아진 폐산에서 산화막 제거속도가 높고 공식발생이 현저하였다. 산세 후 시료의 표면 광택도에 가장 큰 영향을 주는 것은 산세 온도였으며, 산세온도가 높아질수록 표면 광택도는 감소하였다. 동일 산세 조건에서는 폐산 원액을 사용한 경우가 실리콘을 제거공정으로부터 얻어진 용액을 사용한 경우보다 광택도가 높았다.

• 수산해양기술연구
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• 제36권1호
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• pp.45-53
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• 2000

수산시설용 그물감 재료로 많이 사용되고 있는 PE 및 나일론과 신소재섬유로 구성된 Hi-PE 그물실의 내후성 기구를 파악하기 위하여 그물실에 인공광원을 조사한 후 시간의 경과에 따른 그물실 표면의 형태적 변화와 밀도 및 광각X선 회절 측정을 실시하였으며, 이들 결과를 인장시험에 의한 기계적 물성 특성과 비교\ulcorner고찰하였다. 실험의 결과를 요약하면 다음과 같다. 1. 그물실 표면의 형태적 변화는 염색 처리된 PE와 나일론 그물실의 경우에는 표면에 안료가 석출되었을 뿐 균열은 나타나지 않았으나, 미처리된 Hi-PE 그물실의 경우 자외선 etching에 따른 균열의 현저한 증가를 확인할 수 있었다. 2. 그물실의 분자 충진 밀도의 경우, 염색된 PE 및 나일론 그물실의 경우에는 노출시간이 증가함에 따라 큰 변화는 없었으나, Hi-PE 그물실의 경우에는 분자사슬의 재배열과 chain scission 등의 영향에 의해 밀도가 증가하였다. 3. 세 그물실 모두 회절 피크의 2$\theta$에는 큰 변화가 없는 것으로 보아 결정구조의 근본적인 변화는 없다고 생각할 수 있다. 4. 잔여 강도는 염색처리된 PE 및 나일론 그물실에서 각각 90.8%와 75.3%로 높게 나타났으나, 미처리된 Hi-PE 그물실에서는 68.3%로 가장 작았으며, 이는 전자현미경에 의해 촬영된 그물실 표면의 형태적 변화와도 잘 일치하고 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1137-1139
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• 1995

$SiN_x$ films deposited on bare Si and wet-etched Si by RPCVD were fabricated to investigated the effect of wet-etched surface of Si on the characteristics of the interface between $SiN_x$ and Si. FT-IR spectra on each film showed similar characteristics. However, it was confirmed that the electric characteristics(I-V, C-V) of the interface between $SiN_x$ and Si have been degraded by the wet etching process of Si, which is applied for the formation of Si field emitter array. Therefore, we suggest that the stacked structure of insulating layer with good interface characteristics is desirable for FED application.

• 한국결정성장학회지
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• 제8권4호
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• pp.581-586
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• 1998

초크랄스키 실리콘 기판의 뒷면에 형성된 기계적 손상이 미치는 효과에 대하여 고찰하였다. 기계적 손상의 정도는 레이저 여기/극초단파 반사 광전도 감쇠법에 의한 소수반송자 재결합 수명, X-선 단면 측정 및 습식 산화/선택적 식긱 방법으로 평가하였다. 그 결과, 웨이퍼 뒷면에 가해지는 기계적 손상의 세기가 강할수록 소수반송자 재결합 수명은 짧아지고, 산만 산란 정도와 X-선 과잉 강도의 적분값은 비례적으로 증가하였으며, 그 값을 Grade 1의 손상된 웨이퍼에서의 과잉 강도로 정규화하면 과잉 강도의 상대 정량비는 Geade 1:Grade 2:Grade 3 = 1:7:18.4이다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.130.2-130.2
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• 2011

본 연구에서는 RF magnetron sputtering을 이용하여 실리콘 박막 태양전지용 ZnO:Al 전면전극을 제작하고 다양한 식각조건에 따른 ZnO:Al 박막의 표면형상 변화와 함께 전기적 및 광학적 특성 변화를 조사하였다. pin 구조를 갖는 실리콘 박막 태양전지의 효율 향상을 위해서는 입사광의 산란효과에 따른 광포획 증가가 필수적이며 이를 위하여 ZnO:Al 전면전극의 표면텍스처링 형성이 필요하다. 식각용액으로는 HCl과 HF 등을 사용하였으며 식각용액 농도 및 식각시간을 변화시켰다. 식각 후의 ZnO:Al 박막의 표면형상은 SEM(Scanning Electron Microscope)과 AFM(Atomic Force Microscope)을 이용하여 분석을 하였고, UV-visible-nIR spectrometer를 이용하여 총 투과도 및 산란 투과도를 측정하였다. 이 외에도 four-point probe 및 Hall measurement를 이용하여 전기적 특성 변화를 조사하였다. 다양한 식각조건에 따라 제조된 ZnO:Al 박막 위에 실리콘 박막 태양전지를 제작하여 전면전극의 표면형상에 따른 태양전지 성능변화를 비교 분석하였다.