• Bulletin of the Korean Chemical Society
• /
• v.32 no.8
• /
• pp.2732-2736
• /
• 2011

In pH 4.2 HAc-NaAc buffer solution, horseradish peroxidase (HRP) catalyzed $H_2O_2$ oxidation of nanosilver to form $Ag^+$. After centrifugation, $Ag^+$ in the supernatant can be measured by graphite furnace atomic absorption spectrophotometry (GFAAS) at the silver absorption wavelength of 328.1 nm. When HRP concentration increased, the $Ag^+$ concentration in the supernatant increased, and the absorption value enhanced. The HRP concentration in the range of 0.84-50 $ng{\cdot}mL^{-1}$ was linear to the enhanced absorption value (${\Delta}A$), with a regression equation of ${\Delta}A$=0.012C+0.11, correlation coefficient of 0.9988, and detection limit of 0.41 $ng{\cdot}mL^{-1}$ HRP. The proposed GFAAS method was used to detect HRP in waste water samples, with satisfactory results.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.8
• /
• pp.2283-2288
• /
• 2010

Nanostructured copper compounds were grown by electrochemical anodization of copper foil in aqueous NaOH under varying conditions including electrolyte concentration, reaction temperature, current density, and reaction time. Their morphology and atomic composition were investigated by using SEM, TEM, XRD, EDS and XPS. At the conditions ([NaOH] = 1 M, $20^{\circ}C$, $2\;mA\;cm^{-2}$), wire-like orthorhombic $Cu(OH)_2$ nanobundles with an average width of 100 - 300 nm and length of $10\;{\mu}m$ were synthesized with the preferential [100] growth direction. Furthermore, when the concentration decreased to 0.5 M NaOH, the 1D nanobundle structure became narrower and longer without any change in compositions or crystalline structure. Side reaction pathways appeared to compete with the 1D nanostructure formation channels: the formation of CuO nanoleaves at $50^{\circ}C$ via the sequential dehydration of $Cu(OH)_2$, CuO/$Cu_2O$ aggregates in 4 M NaOH, and $Cu_2O$ nanoparticles and CuO nanosheets at lower current density.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 1998.11a
• /
• pp.52-56
• /
• 1998

최근 들어 국외에서는 오염된 지하수의 정화기술로써 0가 금속을 이용한 방법이 높은 잠재력을 가진 신기술로 알려져 있다. 본 연구에서는 0가 금속중 나노크기(1-100nm)를 가진 0가 철입자를 이용하여 수중의 NO$_3$￣를 탈질처리하는 실험을 행하였다. 본 실험에서 제조한 나노크기 0가 철입자는 상온상압의 환원적 조건에서 50, 100, 200, 400mg/$\ell$의 NO$_3$￣와 반응하여 반응시간 30분안에 95%이상 제거되는 높은 반응성을 보여주었다. 기존의 상업용 철입자(10-100$\mu\textrm{m}$)를 이용한 NO$_3$￣의 제거결과에서 보여주는 다량의 철사용, 낮은 적용 오염농도, 그리고 낮은 반응속도등의 문제점에 비하여 나노크기 철 입자는 높은 오염농도범위에서도 적은 철 주입량과 짧은 반응시간 내에 매우 높은 제거효율(10-100배)을 나타내었다. 이러한 결과로 수중의 NO$_3$￣의 고속 탈질반응속도에 영향을 주는 중요한 변수는 반응에 참여하는 철 입자의 비표면적임을 알 수 있었다. 본 연구에서 얻은 batch실험 결과를 바탕으로 NO$_3$￣로 오염된 지하수의 정화를 위한 현장 적용을 목표로 연속처리 공정의 설계를 위한 토대를 마련하고자 하였다.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2006.05a
• /
• pp.105-108
• /
• 2006

It has been issued to fabricate nano-scale patterns with large-scale in the field of digital display. Also, large-scale fabrication technology of nano pattern is very important not only for the field of digital display but also for the most of applications of the nano-scale patterns in the view of the productivity. Among the fabrication technologies, UV nano imprinting process is suitable for replicating polymeric nano-scale patterns. However, in case of conventional UV nano imprinting process using flat mold, it is not easy to replicate large areal nano patterns. Because there are several problems such as releasing, uniformity of the replica, mold fabrication and so on. In this study, to overcome the limitation of the conventional UV nano imprinting process, we proposed a continuous UV nano imprinting process using a pattern roll stamper. A pattern roll stamper that has nano-scale patterns was fabricated by attaching thin metal stamper to a roll base. A continuous UV nano imprinting system was designed and constructed. As practical examples of the process, various nano patterns with pattern size of 500, 150 and 50nm were fabricated. Finally, geometrical properties of imprinted nano patterns were measured and analyzed.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.33A no.7
• /
• pp.134-142
• /
• 1996

The epi-CoSi$_{2}$ layer was formed by alloying a Co(120$\AA$)/Ti(50$\AA$) bilayer. In addition, the ultra shallow p$^{+}$n junction of which depth is about not more than 40nm at the background concentration, 10$^{18}$atoms/cm$^{3}$ could be formed by annealing (RTA-II) the ion implanted epi-silicide. When the temperature of RTA-I is as low as possible and that of RTA-II is moderate, the p$^{+}$n junction that has low leakage current and stable epi-silicide layer could be obtained. That is, when th econdition of TRA-I was 900$^{\circ}C$/20sec and that of RTA-II was 900$^{\circ}C$/10sec, the reverse leakage current was as high as 11.3$\mu$A/cm$^{2}$ at -5V. The surface of CoSi$_{2}$ appeared considerably rough. However, when the conditon of RTA-I was 800$^{\circ}C$/20sec or 700$^{\circ}C$/20sec, the leakage currents were as low as 8.3nA/cm$^{2}$ and 9.3nA/cm$^{2}$, respectively and also the surfaces appeared very uniform.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.495-498
• /
• 2006

The influence of various process parameters for the as-deposited poly silicon was investigated. The polycrystalline silicon films were successfully deposited on glass substrates at a low-temperature $(<200^{\circ}C)$ using the catalytic chemical vapor deposition (Cat-CVD). We achieved a low hydrogen content $({\sim}0.9%)$ and a high deposition rate $({\sim}35{\AA}/sec)$. The film is applicable to thin film transistors on plastic substrates.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2005.07b
• /
• pp.1552-1555
• /
• 2005

We have studied the inkjet patterning of synthesized aqueous silver nano-sol on interface-controlled ITO glass substrate. Furthermore, we designed the conductive ink for direct inkjet patterning on bare ITO glass substrate. The first, the highly concentrated polymeric dispersant-assisted silver nano sol was prepared by variation of molecular weight and control of initial nucleation and growth of silver nanoparticles. The high concentration of batch-synthesized silver nano sol was possible to 40 wt%. At the same time the particle size of silver nanoparticles was below $10{\sim}20nm$. The second, the synthesized silver nano sol was inkjet - patterned on ITO glass substrate. The connectivity and width of fine line depended largely on the wettability of silver nano sol on ITO glass substrate, which was controlled by surfactant. The relationship was understood by wetting angle. The fine line of silver electrode as fine as $50{\sim}100\;{\mu}m$ was successfully formed on ITO glass substrate. The last, the direct inkjet-patternable silver nano sol on bare ITO glass substrate was designed also.

• Journal of Hydrogen and New Energy
• /
• v.16 no.2
• /
• pp.130-135
• /
• 2005

Cadmium selenide is one of the group IIb-VI compounds, which is the promising semiconductor material due to its wide range of technological applications in optoelectronic devices such as photoelectrochemical cells, solid state solar cells, thin film photoconductors etc. CdSe has optical band gap of 1.7-1.8eV and proper conduction band edge for water splitting. CdSe films are coated with small thickness(20-50nm) nanocrystalline $TiO_2$ film by electrodeposition or chemical bath deposition methods and PEC properties of CdSe and CdSe/$TiO_2$ sandwich structure are studied. The photoactivity of CdSe and CdSe/$TiO_2$ films deposited on titanium substrate is studied in aqueous electrolyte of 1M NaOH solution. Photocurrent and photovoltage obtained were of the order of 2-4 mA/$cm^2$ and 0.5V, respectively, under the intensity of illumination of 100 mW/$cm^2$.

• Journal of Electrical Engineering and Technology
• /
• v.1 no.1
• /
• pp.110-113
• /
• 2006

A high rate deposition sputtering process of magnesium oxide thin film in oxide mode has been developed using a 20 kW unipolar pulsed power supply. The power supply was operated at a maximum constant voltage of 500 V and a constant current of 40 A. The pulse repetition rate and the duty were changed in the ranges of $10\sim50$ kHz and $10\sim60%$, respectively. The deposition rate increased with rising incident power to the target. Maximum incident power to the magnesium target was obtained by the control of frequency, duty and current. The deposition rate of a moving state was 9 nm m/min at the average power of 1.5 kW. This result shows higher deposition rate than any other previous work involving reactive sputtering in oxide mode. The thickness uniformities over the entire substrate area of $982mm{\times}563mm$ were observed at the processing pressure of $2.8\sim9.5$ mTorr. The thickness distribution was improved at lower pressure. This technique is proposed for application to a high through-put sputtering system for plasma display panels.

• Journal of the Korean Ceramic Society
• /
• v.32 no.1
• /
• pp.63-70
• /
• 1995

A crack-free ceramic composite membrane with micropores has been synthesized by the pressurized sol-gel coating technique using the mixed Al2O3-SiO2 sols. The mixed sols were prepared by mixing nanoparticulate SiO2 and boehmite sols. These sols were more stable at lower pH, but very unstable when their copositions were in the range of 50~75mol% of SiO2 at the same pH. The mixed Al2O3-SiO2 membrane prepared from the mixed sol (0.2mol/$\ell$ of solid content and pH=2) containing 40mol% of SiO2 had the mean pore radius of 0.80nm and the specific surface area of 280$m^2$/g. The nitrogen permeability through the coated Al2O3-SiO2 layer was 42$\times$107mol/$m^2$.s.Pa. It was found that the thermal stability of aluminosilicate membranes, even through similar to that of SiO2 membranes, was much improved in comparison with ${\gamma}$-alumina membranes.