Pollutants removal and disinfection effect of secondary effluent from final settling tank of sewage treatment plant of W city were investigated in Loop Reactor using ordinary granular activated carbon(GAC) and GAC coated with silver nanoparticles. The results showed that the removal efficiency of CODMn, T-N and T-P using GAC with silver nanoparticles were higher than using the ordinary GAC. The removal efficiency of T-P using GAC with silver nanoparticles is 45.4% and that of T-P using ordinary GAC is 30.9% in the same case of the input amount of 20 g/L of GAC. The total califorms is reduced according to increasing input amount of GAC with silver nanoparticles and ordinary GAC. The disinfection efficiency of total coliforms in case of GAC with silver nanoparticles is much higher than that in case of ordinary GAC. For all experiments using the silver nanoparticles, the total coliforms is under 26 cfu/mL and this shows very excellent disinfection effect.

Ag nanoparticles are extensively studied and utilized due to their excellent catalysis, antibiosis and optical properties. They can be easily synthesized by chemical reduction methods and it is possible to prepare particles of uniform size and high purity. These methods are divided into vapor methods and liquid phase reduction methods. In the present study, Ag particles are prepared and analyzed through two chemical reduction methods using solvents containing a silver nitrate precursor. When Ag ions are reduced using a reductant in the aqueous solution, it is possible to control the Ag particle size by controlling the formic acid ratio. In addition, in the Polyol process, Ag nanoparticles prepared at various temperatures and reaction time conditions have multiple twinned and anisotropic structures, and the particle size variation can be confirmed using field emissions scanning electron microscopy and by analyzing the UV-vis spectrum.

Recent Engineered nanoparticles were increasingly exposed to environmental system with the wide application and production of nanomaterials, concerns are increasing about their environmental risk to soil and groundwater system. In order to assess the transport behavior of silver nanoparticles (AgNPs), a saturated packed column experiments were examined. Inductively coupled plasma-mass spectrometry and a DLS detector was used for concentration and size measurement of AgNPs. The column experiment results showed that solution chemistry had a considerable temporal deposition of AgNPs on the porous media of solid glass beads. In column experiment, comparable mobility improvement of AgNPs were observed by changing solution chemistry conditions from salts (in both NaCl and CaCl2 solutions) to DI conditions, but in much lower ionic strength (IS) with CaCl2. Additionally, the fitted parameters with two-site kinetic attachment model form the experimental breakthrough curves (BTCs) were associated that the retention rates of the AgNPs aggregates were enhanced with increasing IS under both NaCl and CaCl2 solutions.

Facilitated olefin transport membrane, containing positively charged silver nanoparticles (AgNPs) as olefin carriers dispersed in poly(vinyl pyrrolidone) (PVP), leads extremely high separation performances for propylene/propane mixtures. In this study, as representatives of electron withdrawing nitrobenzene compounds, 1,2-dinitrobenzene (DNB) and 3,4-dinitro toluene (DNT) were used for PVP/AgNPs membranes. The correlation between the surface charge density of AgNPs and the separation performance was investigated with X-ray photoelectron spectroscopy (XPS). A fairly good linear correlation between the surface charge density and the separation performance was confirmed, which meant that the positive charge density on the surface of AgNPs may be a key factor in determining the separation performance of facilitated olefin transport membranes.

고분자막이 가진 수투과능 한계와 비가역적 막오염에 의한 효율 저하는 막기반 수처리공정의 추가적인 경쟁력 확보를 위해 해결해야 하는 문제이다. 본 연구에서는 초고속 물투과 특성과 뛰어난 선택성을 지닌 Graphene oxide (GO)막 에 뛰어난 항균성을 가진 은나노(nAg)가 코팅된 막을 제작, 평가하였다. GO막 은 막오염 저감에 효과적일 수 있는 높은 친수성과 음표면전하와 같은 특성과 막오염에 취약할 수 있는 높은 비표면적과 뛰어난 흡착능력과 같은 특성을 동 시에 가진다. 따라서, 논란의 부분이 있는 GO막의 막오염에 대한 저항성의 확실한 향상을 위해 nAg를 적용하였다.

고성능 투명 전극의 개발은 유기 태양 전지, 유기 발광 다이오드와 같은 저가형 유연 유기 광전자 소자의 개발에 매우 중요하다. 가장 널리 쓰이고 있는 투명전극인 indium tin oxide (ITO)는 비싼 가격과 잘 깨어지는 특성 을 가지고 있어서 저가형 유연 전자 소자의 개발에 많은 제한을 주고 있으며, 이를 극복하기 위한 대체 투명 전극의 개발에 대한 연구가 활발히 진행되고 있다. 은 나노와이어(silver nanowire, AgNW)는 우수한 전기 전도도와 광 투과 도를 가지고 저렴하며 뛰어난 유연성 때문에 ITO의 대체 투명전극으로서 큰 각광을 받고 있다. 그러나 AgNW의 거 친 표면은 유기 광전자 소자의 누설전류를 크게 증가시켜서 소자의 효율을 떨어뜨리기 때문에 이를 극복하는 기술의 개발이 시급한 실정이다. 본 연구에서는 UV 광 경화성 접착제를 이용하여 AgNW를 PET기판으로 transfer 시키는 방법으로 AgNW가 매몰된 유연 전도성 투명 기판을 제작하였으며, 이 기판은 낮은 표면 거칠기, 낮은 면저항과 높은 광투과도를 보여준다. 본 연구에서 개발된 AgNW가 매몰된 유연 전도성 투명 기판은 유기전자소자의 대체투명전극 으로 활용될 수 있는 가능성을 보여준다.

This study focuses on fabricating silver flake powder by a mechanical milling process and investigating the formation of flake-shaped particles during milling. The silver flake powder is fabricated by varying the mechanical milling parameters such as the amount of powder, ball size, impeller rotation speed, and milling time of the attrition ballmill. The particle size of the silver flake powder decreases with increasing amount of powder; however, it increases with increasing impeller rotation speed. The change in the particle size of the silver flake powder is analyzed based on elastic collision between the balls, taking energy loss of the balls due to the powder into consideration. The change in the particle size of the silver flake powder with mechanical milling parameters is consistent with the change in the diameter of the elastic deformation contact area of the ball, due to the collision between the balls, with milling parameters. The flake-shaped silver particles are formed at the elastic deformation contact area of the ball due to the collision. Keywords: Flake powder, Milling, Ball collision, Elastic deformation

이 연구는 중국 감숙성 사막지역에서 사막화확산 방지를 위한 사막복구조림을 실시함으로써 장기적으 로 사막화지역에 적합한 사방기술을 향상시키는데 기여하고자 수행하였다. 조사지역의 음지와 반음지쪽 비탈면의 피복율은 10~20%이었으며, 양지와 반양지쪽 비탈면의 피복율은 5~10%이었다. 이 지역의 토 양은 회색칼슘토양으로 전체면적의 82.2%를 점유하고, 토양 중에는 칼륨함량이 많고 질소, 인의 함량 이 낮은 것으로 나타났다. 조사지에서 토양의 용적밀도는 0.98~1.27g/cm3로 나타났으며, 조사지역의 토양 pH는 8.2~9.0으로 강알칼리성이었다. 현존률은 2002년도에 조림한 지역이 가장 높은 경향을 나 타내었으며, 전 조사지에서 현존률은 86% 이상이었다. 신초생장량은 2001년도에 조림한 지역에서 37.9~139.8cm, 2002년 조림지역에서 32.4~116.5cm, 2001년 조림지역에서 14.5~96.7cm로 나타났으 며, 활엽수종으로는 백양나무와 아까시나무의 신초생장량이 가장 높은 것으로 나타나 감숙성 백은시 사 막지역에 가장 적합한 수종인 것으로 판단된다.

In this study, the properties of Ag-coated TiO2 nanoparticles were observed, while varying the molar ratio of water and Ag+ for the surfactant and TiO2. According to the XRD results, each nanoparticle showed a distinctive diffraction pattern. The intensity of the respective peaks and the sizes of the nanoparticles increased in the order of AT1(R1 = 5)(33.3 nm), AT2 (R1 = 10)(38.1 nm), AT3(R1 = 20)(45.7 nm), AT4(R1 = 40)(48.6 nm) as well as AT5(R2 = 0.2, R3 = 0.5)(41.4 nm), AT6(R2 = 0.3, R3 = 1)(45.1 nm), AT7(R2 = 0.5, R3 = 1.5)(49.3 nm), AT8(R2 = 0.7, R3 = 2)(57.2 nm), which values were consistent with the results of the UV-Vis. spectrum. The surface resistance of the conductive pastes fabricated using the prepared Ag-coated TiO2 nanoparticles exhibited a range 7.0~9.0(274~328 μΩ/cm2) times that of pure silver paste(ATP)(52 μΩ/cm2).

One-dimensional (1D) silver nanostructures, which possess the highest conductivity among all room-temperature materials, moderate flexibility and high transmittance, are one of the most promising candidate materials to replace conventional indium tin oxide transparent electrodes. However, the short length and large diameter of 1D silver nanostructures cause a substantial decrease in the optical transparency or an increase in the sheet resistance. In this work, ultra-long silver nanofiber networks were synthesized with a low-cost and scalable electrospinning process, and the diameter of the nanofibers were finetuned to achieve a higher aspect ratio. The decrease in the diameter of the nanofibers resulted in a higher optical transparency at a lower sheet resistance: 87 % at 300 Ω/sq, respectively. It is expected that an electrospun silver nanofiber based transparent electrode can be used as a key component in various optoelectronic applications.

The silver nanoparticles (AgNPs) incorporated reverse osmosis (RO) membranes with an excellent antibacterial property has been reported. However, the incorporated AgNPs could increase the hydraulic resistance of membrane, indicating the decline of water flux. Here, hybrid silver nanoparticles (Ag@SiO2, 400 nm) were strongly immobilized using Ag-S chemical bonding on the polyamide surface of RO membrane for both protecting the decline membrane performance and having a strong antimicrobial property. The membrane performance was unchanged after the immobilization of silver nanoparticles, when compared to that of unmodified membrane. In addition, the silver-polyamide composite membrane significant reduced the number of live bacteria attached on the membrane surface by 92.7 ± 1.8, 99.5 ± 0.3, and 73.3 ± 5.5% for E. coli, P. aeruginosa, and S. aureus, respectively. The strong antimicrobial property is ascribed to the combination effect by the directly attachment to bacteria surface and the penetration of released silver ions inside the cell membrane of bacteria.

Soil column experiments were evaluated effects of silver nanoparticles (i.e., 0, 2.5, 5, and 10 mg/L) on the microbial viability which is strongly associated with the degradation of organic matter, pharmaceutically active compounds(PhACs) and biological oxidation of nitrogenous compounds during river bank filtration. The addition of silver nanoparticles resulted in almost no change in the aqueous matrix. However, the intact cell concentration decreased with addition of silver nanoparticles from 2.5 to 10 mg/L, which accounted for 76% to 82% reduction compared to that of control (silver nanoparticles free surface water). The decrease in adenosine triphosphate was more pronounced; thus, the number and active cells in aqueous phase were concurrently decreased with added silver nanoparticles. Based on the florescence excitation-emission matrix and liquid chromatograph - organic carbon detection analyses, it shows that the removal of protein-like substances was relatively higher than that of humic-like substances, and polysaccharide was substantially reduced. But the extent of those substances removed during soil passage was decreased with the increasing concentration of silver nanoparticles. The attenuation of ionic PhACs ranged from 55% to 80%, depending on the concentration of silver nanoparticles. The attenuation of neutral PhACs ranged between 72% and 77%, which was relatively lower than that observed for the ionic PhACs. The microbial viability was affected by silver nanoparticles, which also resulted in inhibition of nitrifiers.

본 연구에서는 석유화학공정 중에서 많은 에너지를 소비하는 NCC(Naphtha Cracking Center) C3 splitter를 대신하여 에너지 소비가 적고 친환경 공정인 막분리법을 이용하여 프로필렌/프로판의 분리특성을 예측하고자 한다. 막소재로는 프로필렌/프로판 분리에 대하여 우수한 성능을 나타내는 것으로 잘 알려진 촉진수송막을 사용하였다. 실험에 사용된 촉진수송막은 한양대학교에서 제조한 은나노입자가 함유된 VP/AgBF4/TCNQ 용액을 에어레인에서 다공성 폴리이서이미드 중공사에 얇게 코팅하여 소형 중공사 막모듈로 제작하였다. 제작된 촉진수송막 모듈의 투과성능을 평가하기 위하여 프로필렌과 프로판에 대한 단일기체 테스트를 진행하였다. 분리막의 투과현상을 예측하기 위하여 전산모사 프로그램을 개발하였다. 개발된 전산모사 프로그램에 단일기체 테스트를 통해 얻어진 투과도와 선택도를 이용하여 95/5 vol% C3H6 / vol% C3H8 혼합가스를 공급하였을 경우, 공급측 및 투과측 압력 변화에 따른 투과측 프로필렌의 농도가 99.5 vol%를 유지하는 단일 분리막 공정을 설계하였다.

This study is focused on investigating the relation between the particle size of silver flake powder and mechanical milling parameters. Mechanical milling parameters such as ball size, impeller rotation speed and milling time of the attrition ball-mill were controlled to produce silver flake powder. The particle size of the silver flake powder increased with increasing ball size and impeller rotation speed. The change of the particle size of the silver flake powder with mechanical milling parameters was analyzed based on balls motion in the mill container of the attrition ball-mill. The silver flake particles were formed at the elastic deformation area of the ball due to the collision between balls. The change of the particle size of the silver flake powder with mechanical milling parameters well consists with the change of the collision energy of ball with parameters mentioned above.

Since airborne fungi have been known to aggravate indoor air quality, studies on developing anti-fungal filters increase recently. In this study, silver (Ag) nanoparticle was selected as anti-fungal agent. HEPA filter was coated with silver nanoparticles which were generated via spark discharge system operating at atmospheric pressure and temperature. The anti-fungal effect of the Ag-filter was evaluated with the conventional culture assay. When the number of Ag nano particle per a fungal particle in the filter was 1.91X106, the fungicidal efficiency was higher than 99%. As another anti-fungal test, ATP bioluminiscence detection method was also carried out and the results were correlated with those of the culture assay.

In order to produce size-controllable Ag nanoparticles and a nanomesh-patterned Si substrate, we introduce a rapid thermal annealing(RTA) method and a metal assisted chemical etching(MCE) process. Ag nanoparticles were self-organized from a thin Ag film on a Si substrate through the RTA process. The mean diameter of the nanoparticles was modulated by changing the thickness of the Ag film. Furthermore, we controlled the surface energy of the Si substrate by changing the Ar or H2 ambient gas during the RTA process, and the modified surface energy was evaluated through water contact angle test. A smaller mean diameter of Ag nanoparticles was obtained under H2 gas at RTA, compared to that under Ar, from the same thickness of Ag thin film. This result was observed by SEM and summarized by statistical analysis. The mechanism of this result was determined by the surface energy change caused by the chemical reaction between the Si substrate and H2. The change of the surface energy affected on uniformity in the MCE process using Ag nanoparticles as catalyst. The nanoparticles formed under ambient Ar, having high surface energy, randomly moved in the lateral direction on the substrate even though the etching solution consisting of 10 % HF and 0.12 % H2O2 was cooled down to -20˚C to minimize thermal energy, which could act as the driving force of movement. On the other hand, the nanoparticles thermally treated under ambient H2 had low surface energy as the surface of the Si substrate reacted with H2. That's why the Ag nanoparticles could keep their pattern and vertically etch the Si substrate during MCE.

규범 문법에서 격조사와 보조사로 논의되어 왔던 ‘이/가’, ‘을/를’, ‘은/는’은 문장문법으로 설명이 불가능한 화용적 양상을 보이며 담화 구성에 관여하는 맥락적 요소에 의해 운용이 결정되기도 한다. 문장은 생성 단계에서부터 발화를 목적으로 하며 고립적으로 존재하는 것이 아니라 담화를 구성하는 단위로서 의도와 목표를 지닌다. 의사소통에 있어 화자는 자신의 의도 즉 메시지를 효과적으로 전달하기 위해 문법적 장치를 사용하는데 화자의 의도를 반영하는 문법적 장치는 통사적 층위를 넘어선 발화조직 층위에서 그 운용이 결정된다고 본다. 규범 문법에서 통사적 구성체로 다루어졌던 ‘이/가’, ‘을/를’, ‘은/는’은 통사 층위뿐만 아니라 발화 조직 층위에서 다루어져야 하는 담화적 구성체이다. ‘이/가’, ‘을/를’, ‘은/는’은 화맥, 화․청자와의 관계, 의식, 전제, 함축 등의 맥락적 요소와 문장의 정보구조에 의해 사용이 결정된다. 따라서 조사의 올바른 이해와 사용을 위해서는 조사의 사용 맥락이 규명되어야 하며 조사 교육에 있어 조사의 사용 맥락이 교수되어야 한다고 본다.

목적: 본 연구는 furfuryl isocyanate를 은 나노 물질(Ag nanoparticler)과 기존의 하이드로젤 곤택트렌즈 재료와 공증합 하였으며, 제조된 콘택트렌즈의 물리적 특성을 비교하고, 내구성이 높은 콘택트렌즈 고분자로서의 활용성을 알아보았다. 방법: 교차결합제인 EGDMA(ethylene glycol dimethacrylate)와 HEMA(2-hydroxyethyl methacry-Late), MMA(methyl methacrylate), MA(merhacrylic acid) 그리고 개시제인 AIBN(azobisisobutyronitrile)과 함께 공증합 하였다. 결과: 생성된 고분자의 물리적 특성을 측정한 결과, 함수율 28.98~34.31%, 굴절률 1.441~1.453,UV-B투고율 33.2~72.0%, 접촉각 57.65~79.00° 그리고 인장강도의 경우 0.340~0.71kgf 범위의 분포를 나타내었다. 또한 은 나노 물질 1%에 furfuryl isocyanate를 첨가할수록 UV-B 투과율 저하와 인장강도가 증가한 결과를 보였다. 결론: 본 실험결과로 볼 때 생성된 공중합체는 내구성이 좋고 자외선 차단 효과가 있는 렌즈 재료로 유용하게 활용될 것으로 기대된다.

Metal nanowires can be coated on various substrates to create transparent conducting films that can potentially replace the dominant transparent conductor, indium tin oxide, in displays, solar cells, organic light-emitting diodes, and electrochromic windows. One issue with these metal nanowire based transparent conductive films is that the resistance between the nanowires is still high because of their low aspect ratio. Here, we demonstrate high-performance transparent conductive films with silver nanofiber networks synthesized by a low-cost and scalable electrospinning process followed by two-step sequential thermal treatments. First, the PVP/AgNO3 precursor nanofibers, which have an average diameter of 208 nm and are several thousands of micrometers in length, were synthesized by the electrospinning process. The thermal behavior and the phase and morphology evolution in the thermal treatment processes were systematically investigated to determine the thermal treatment atmosphere and temperature. PVP/AgNO3 nanofibers were transformed stepwise into PVP/Ag and Ag nanofibers by two-step sequential thermal treatments (i.e., 150˚C in H2 for 0.5 h and 300˚C in Ar for 3 h); however, the fibrous shape was perfectly maintained. The silver nanofibers have ultrahigh aspect ratios of up to 10000 and a small average diameter of 142 nm; they also have fused crossing points with ultra-low junction resistances, which result in high transmittance at low sheet resistance.