• The Journal of Korean Academy of Prosthodontics
• /
• v.52 no.3
• /
• pp.177-185
• /
• 2014

Purpose: This study is designed to investigate the various impacts of different types of scaler tips such as cooper alloy base tip and the others on the surface roughness of teeth and implant by the method which is currently in clinical use. Materials and methods: Four different types of disc shaped porcelain, titanium, zirconia, and Type III gold alloy dental materials sized 15 mm diameter, 1.5 mm thickness were used for the experiment. Plastic hand curette (Group PS), cooper alloy new tip (Group IS), and stainless steel tip (Group SS) were used as testing appliances. A total of 64 specimens were used for this study; Four specimens for each material and appliance group. Surface roughness was formed with 15 degree angle in ultrasonic scaler tip and with 45 degree angle in hand curette of instrument tip and the specimen surface with 5 mm long, one horizontal-reciprocating motion per second for 30 seconds by 40 g force. To survey the surface roughness of each specimen, a field emission scanning electron microscope, an atomic force microscope, and a surface profiler were used. (Ra, ${\mu}m$). Results: According to SEM, most increased surface roughness was observed in SS group while IS groups had minimal roughness change. Measurement by atomic force microscope presented that the surface roughness of SS group was significantly greater than those of PS, IS and control groups in the type III gold alloy group (P<.05). IS group showed lesser surface roughness changes compared to SS group in porcelain and gold alloy group (P<.05). According to surface profiler, surface roughness of SS group showed greater than those of PS, IS and control groups and IS group showed lesser than those of SS group in all specimen groups. Type III gold alloy group had large changes on surface roughness than those of porcelain, titanium, zirconia (P<.05). Conclusion: The result of this study showed that newly developed copper alloy scaler tip can cause minimal roughness impacts on the surface of implant and dental materials; therefore this may be a useful alternative for prophylaxis of implant and restored teeth.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.12 no.2
• /
• pp.113-117
• /
• 1979

The short-term acute toxicities of mercury, cadmium and copper for the clam, Meretrix lusoria were determined from 28 June to 15 July, 1978. In the test with mercury and copper, the rate ot mucus excretion increased gradually at a higher concentration. But the clams did not excrete mucus in the solutions of cadmium and natural sea water. The rate of mucus excretion in mercury was $42.9\%$, and that in copper was $14.3\%$ in a test solution of 1mg/l. mercury was more toxic than copper. The median lethal concentration after 96 hours (96 hr-Lc 50) was 0.67mg/l in mercury, 7.04mg/l in copper and 7.10mg/l in cadmium. Consequently it was found that mercury was the most toxic substance and cadmium was the least. meanwhile, it was considered that exposure time by stimulation in a fixed concentration caused the test animals to respond.

• Korean Chemical Engineering Research
• /
• v.48 no.1
• /
• pp.33-38
• /
• 2010

A microfluidic system has been developed using biomaterial for the measurement of cupric ion concentration. The cell-membrane-mimicking bilayer lipid membrane(BLM)-coated silver electrode was used for the sensing of cupric ion concentration. The silver-supported BLM could increase its stability. A silver-supported bilayer lipid membrane(s-BLM) was easily obtained using its self-assembling characteristics by immersing silver wire into lipid(phosphatidylcholine; PC) solution and then dipping into aqueous KCl solution. These s-BLMs were used to determine the relationship between $Cu^{2+}$ concentration and current crossing s-BLM. Their relationship showed high linearity and reproducibility. The calibration curve was constructed to express the relationship between $Cu^{2+}$ concentration and current in the $Cu^{2+}$ concentration range of 10 and $130{\mu}M$. This calibration curve was used to measure $Cu^{2+}$ concentration in an unknown sample. Microfluidic system with s-BLM was made of PDMS(polydimethyl siloxane) using typical soft photolithography and molding technique. This integrated system has various functions such as activation of the silver surface without cutting silver wire, coating of BLM on silver surface, injection of KCl buffer solution, injection of $Cu^{2+}$ sample and measurement of $Cu^{2+}$ concentration in the sample.

• The Korean Journal of Malacology
• /
• v.14 no.1
• /
• pp.51-59
• /
• 1998

담수산 이매패류인 참재？, Corbicula leana를 대상으로 크기와 수온별로 카드뮴, 구리 및 수은 등의 중금속에 노출시켜 반수치사농도, 호흡률 및 여수율 등의 생리적 내성에 관하여 알아보았다. 17%C에서 작은 개체rnhr,-LC$^{50}$ 은 수은이 1.63 ppm이었으며, 카드뮴과 구리는 각각 7.45및 8.71 ppm으로서 수은에 비해 상당히 높은 값을 나타내었다. 큰 개체구의 경우는 수은이 2.62ppm이었으며, 카드뮴과 구리가 각각10.15와 10.20 ppm이었다. 22$^{\circ}C$의 경우 작은 개체구의 96 hr-LC$^{50}$ ppm은 카드뮴, 구리 및 수은이 각각 5.94, 7.08및 1.63 ppm이었으며, 큰 개체구에서는 각각 8.29, 8.35, 1.87ppm으로서 두수온구에서 모두 작은 개체구에서 중금속 오염원에 의한 영향이 컸으며, 독성순위는 수은>카드뮴>구리 순이었다. 한편 중금속 오염원에 노출시킨 참재첩의 수온-개체크기별 산소소비율과 여수율은 오염원의 농도증가에 따라 고수온에서 영향을 많이 받았으며, 특히 수은의 경우, 22%C-작은 개체구에서 호흡률이 50.7%, 여수율이 52.15%감소되고 있어 여수율이 보다 크게 영향을 받았다.

• Proceedings of the Optical Society of Korea Conference
• /
• 1991.06a
• /
• pp.9-12
• /
• 1991

방전가열형 구리증기레이저의 비축형 불안정공진기를 사용하여 레이저의 빔발산각을 안정공진기의 경우에 비해 25배 (200 $\mu$rad) 까지 줄였다. 이때 불안정공진기의 배율 M 은 50 이었으며, 평균출력은 안정공진기를 사용할 경우에 비해 53 %를 얻었다. 또한, M이 8.5 일 때 (750 $\mu$rad) 평균출력은 안정공진기의 94% 까지 도달하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2018.06a
• /
• pp.77-77
• /
• 2018

Panel level packaging (PLP) 공정은 차세대 반도체 패키징 기술로써 wafer level packaging 대비 net die 면적이 넓어 생산 단가 절감에 유리하다. PLP 공정에 적용되는 구리 재배선 층 (RDL, redistribution layer)은 두께 불균일도에 의해 전기 저항의 유동이 민감하게 변화하기 때문에 RDL의 두께를 균일하게 형성하는 것은 신뢰성 측면에서 매우 중요하다. 구리 RDL은 주로 도금 공정을 통해 형성되며, 균일한 도금막 형성을 위해 도금조에 평탄제를 첨가하여 도금 속도를 균일하게 한다. 도금막에 대한 흡착은 주로 평탄제의 imine 작용기에 포함된 질소 원자가 관여하며, imine 작용기의 4차화에 의한 평탄제의 흡착 정도를 제어하여 평탄제 성능을 개선할 수 있다. 본 연구에서는 도금 평탄제에 포함된 imine 작용기의 질소 원자를 4차화하여 구리 RDL의 도금 두께 불균일도를 제어하고자 하였다. 유기첨가제와 4차화 반응을 위해 알킬화제로써 dimethyl sulfate의 비율을 조절하여 각각 0, 50, 100 %로 4차화 반응을 진행하였다. 평탄제의 4차화 여부를 확인하기 위해 gel permeation chromatography (GPC) 분석을 실시하였다. 도금은 20 ~ 200 um의 다양한 배선 폭을 갖는 구리 RDL 미세패턴에서 진행하였으며, 4차화 평탄제를 첨가하여 광학 현미경과 공초점 레이저 현미경을 통해 도금막 표면과 두께에 대한 분석을 실시하였다. GPC 분석을 통해 4차화 반응 후 알킬화제에 의해 나타나는 GPC peak이 감소한 것을 확인하였다. 광학 현미경 및 공초점 레이저 현미경 분석 결과, 4차화된 질소 원자가 존재하지 않는 평탄제의 경우, 도금 시 도금막의 두께가 불균일하였으며 단면 분석 시 dome 형태가 관찰되었다. 또한 100 % 4차화를 실시한 평탄제를 첨가하여 도금 한 경우 마찬가지로 두께가 불균일한 dish 형태의 도금막이 형성되었다. 반면, 50 % 4차화를 적용한 평탄제를 첨가한 경우, 도금막 단면의 형태는 평평한 모습을 보였으며 매우 양호한 균일도를 가지는 것으로 확인되었다. 이로 인해 imine 작용기를 포함한 평탄제의 4차화 반응을 통해 구리 RDL의 단면 형상 및 불균일도가 제어되는 것을 확인하였으며, 4차화된 imine 작용기의 비율을 조절하여 높은 균일도를 갖는 구리 RDL 도금이 가능한 것으로 판단되었다.

• Applied Biological Chemistry
• /
• v.28 no.2
• /
• pp.68-75
• /
• 1985

Laboratory experiments were conducted to investigate the effect of compost and humic acid treatment on adsorption of Cd, Zn, and Cu in soils. Three soils differing in physical and chemical properties used in this experiments were Bonyrang (Typic Udifluvents) SL, Gangseo (Aquatic Eutrochrepts) L, and Gyorae (Typic Distrandepts) SiL. Adsorption of Cd, Zn, ana Cu on the soils followed Langmuir isotherm up to 75 ppm of initial concentration. The adsorption maxima of Cd, Zn, and Cu for the Bonryang soil, the lowest in pH, organic matter content, and CEC, were the lowest of the three soils. Although the Gyorae soil derived from volcanic ash was the highest in organic matter content and CEC, the adsorption maxima of heavy metals for the Gyorae soil were lower than those for the Gangseo soil of which organic content and CEC were intermidiate. The adsorption maxima/CEC ratios for the Bonryang, the Gangseo, the Gyorae soils were found to be in the range of $23{\sim}27%,\;28{\sim}57%$, and $11{\sim}14%$ respectively The bonding energy constants of Cd, Zn, and Cu for the soils were in the order of Gangseo>Bonryang>Gyorae soils. The adsorption maxima of Cd, Zu, and Cu for the Bonryang soil increased with compost treatment by $100{\sim}210%,\;90{\sim}230%$, and $130{\sim}290%$ respectively, while little difference was observed when the soil was treated with humic acid Bonding energy constants of Cd, Zn, and Cu for the Bonryang soil increased significantly with compost treatment, and showed insignificant correlation with humic acid treatment.

• Proceedings of the Korean Vacuum Society Conference
• /
• 1999.07a
• /
• pp.141-141
• /
• 1999

전기화학과 초고진공(ultra-high vacuum, UHV) 분광법을 이용하여 고체/액체의 계면에서 일어나는 현상을 분자단위에서 이해하고 조절하기 위한 연구를 수행하였다. 이들 중 전기화학으로 형성된 구리 및 은 금속(sub)monlayer 박막을 그 예로 선택하여 소개한다. 초박막 금속의 흡착량은 cyclic voltammogram과 새로 개발된 Auger electron spectroscopy (AES) 정량법을 통해 얻어졌고, 이 값들은 low energy electron diffraction (LEED) 및 in-situ atomic force microscopy (AFM)법을 이용한 구조 분석결과와 비교되어졌다. 또한 화학상태를 확인하기 위하여 core-level electron energyy loss spectroscopy (CEELS)를 사용하였다. 먼저 황산 전해질에서 금(111) 단결정 전극상에 전기화학적으로 형성된 굴의 계면특성을 조사하였다. 특정 전위값에서 2/3 ML의 구리와 1/3 ML의 음이온이 상호 흡착하여 ({{{{ SQRT { 3} }}$\times${{{{ SQRT { 3} }}) 격자 구조를 보였고, 전위값이 커지거나 줄어들면, 이 구조가 사라지는 현상이 관찰되었다. 즉 이 ({{{{ SQRT { 3} }}}}$\times${{{{ SQRT { 3} }}}}) 흡착구조는 첫 번째 UPD underpotential deposition) 피크에 특이하게 관련되어 있음을 알 수 있었다. 금속 초박막 형성에 미치는 음이온의 영향을 좀 더 확인하기 위해 초박막 은이 증착된 금 단결정 전극상의 황산 음이온에 관하여 연구하였다. 은의 증착이 일어날 수 없는 양전위값 영역에서 ({{{{ SQRT { 3} }}}}$\times${{{{ SQRT { 3} }}}})의 규칙적인 음이온의 구조를 보였다. 그리고 은의 장착은 세척 과정과 용액의 농도에 따라 p(3$\times$3)과 p(5$\times$5)의 규칙적인 두가지 구조를 가졌다. in-situ AFM에서는 p(3$\times$3)의 은 증착 구조만 나타났고, 음 전위값으로 옮겨가면 p(1$\times$1) 구조로 바뀌었다. ex-situ 초고진공 결과와 이 AFM의 in-situ 결과를 상호 비교 논의할 것이다. 음이온의 흡착이 없는 묽은 플로르산(HF) 전해질에서 은은 전위값을 음전위 쪽으로 이동해 감에 따라 p(3$\times$3), p(5$\times$5), (5$\times$5), (6$\times$6), 그리고 (1$\times$1)의 연속적 구조 변화를 보였다. 이 다양한 구조들을 AES로부터 얻어진 표면 흡착량과 연결시켰더니 정량적으로 잘 일치되는 결과를 보였다. 전기화학적인 증착에서는 기존의 진공 증착과 비교할 때 음이온의 공흡착이 금속 초박막 형성 메카니즘에 큰 영향을 미침을 알 수 있었다. 또한 은의 전기화학적 다층박막 성장은 MSM (monolayer-simultaneous-multilayer) 메카니즘을 따름을 확인하였다. 마지막으로 구조 및 양이 규칙적으로 조절되는 전극의 응용가능성이 간단히 논의될 것이다.

• Applied Chemistry for Engineering
• /
• v.33 no.6
• /
• pp.574-580
• /
• 2022

While in the process of electroless plating of dendrite-shape copper with silver, various silver-coated copper (Ag@Cu) particles were prepared by using both displacement plating and reducing electroless plating. The physicochemical properties of Ag@Cu particles were analyzed by scanning electron microscope- energy-dispersive X-ray spectroscopy (SEM-EDS), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Brunauer-Emmett-Teller analysis (BET), and it was confirmed that the silver coated by the reducing electroless plating was formed as nano-particles on the copper surface. Ag@Cu particles were compounded with an epoxy resin to prepare a conductive film, and its thermal stability was evaluated. We investigated the effect of the difference between the displacement plating and reducing electroless plating on the initial resistance and thermal stability of conductive films.

• Journal of Korean Society of Environmental Engineers
• /
• v.29 no.8
• /
• pp.930-937
• /
• 2007

Korean pine(Pinus densiflora) bark was evaluated for its adsorption capacity of Cu(II) ions from aqueous solution by running a series of batch experiments. Prior to the tests, the milled barks were treated with 1 N NaOH or 1 N HCl to examine the effect of surface modification. For comparison, untreated bark was tested under same condition. Within the tested pH range between 3 and 6, NaOH treatment increased Cu(II) adsorption capacity by $139\sim184%$, while HCl treatment decreased it by $37\sim42%$. Maximum copper ion uptake by bark was observed at pH $5\sim6$, but pH of solution was not a potent influence. A pseudo second-order kinetic model fitted well for the sorption of copper ion onto bark. For NaOH-treated bark, the calculated sorption capacity$(q_e)$ increased from 6.58 to 12.77 mg/g, while the equilibrium rate constant$(k_2)$ decreased from 0.284 to 0.014 g/mg/min as initial Cu(II) concentration doubled from 100 mg/L. A batch isotherm test using NaOH-treated bark showed that equilibrium sorption data were represented by both the Langmuir model and the Freundlich model. It was confirmed that carboxylic acid of bark was involved in the Cu(II) adsorption. For NaOH-treated bark, in particular, carboxylate ion produced by hydrolysis or saponification appeared to be a major functional roup responsible for the enhanced Cu(II) sorption.