• Journal of Microbiology and Biotechnology
• /
• 제12권5호
• /
• pp.849-853
• /
• 2002

Metal ions have an adverse effect on anaerobic digestion. In an acetate degradation test of upflow of anaerobic sludge blanket granules with $Cu^{2+}$, not all of the acetate that disappeared was stoichiometrically converted to methane. In the presence of 400 mg/g-VSS (volatile suspended solids) $Cu^{2+}$, only 26% of the acetate consumed was converted to methane. To study acetate conversion by other anaerobic microorganisms, sulfate and nitrate reductions were investigated in the presence of $Cu^{2+}$ Sulfate and nitrate reductions exhibited more resistance to $Cu^{2+}$than methanogenesis, and the granules reduced 2.2 mM and 5.4 mM of nitrate and sulfate, respectively, in the presence of 400 mg/g-VSS copper ion. However, the acetate degraded by sulfate and nitrate reductions was only 24% of the missing acetate that could have been stoichiometrically converted to $CO_2$. Accordingly, 76% of the acetate consumed appeared to have been converted to other unknown compounds.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 1998년도 제14회 학술발표회 논문개요집
• /
• pp.41-41
• /
• 1998

Rare earth metal films have been used as a buffer layer for growing ferroelectric t thin film or a seed layer for magnetic multilayer. But when it was deposited on s semiconductor substrates for the application of magneto-optic (MO) storage media, it i is difficult to exactly measure magnetic cons떠nts due to shunting current, and so it n needs to grow metal films on insulator substrate to reduce such effect. Recently, it w was reported that ultra-thin Pt layer were epitaxially grown on A12O:J by ion beam s sputtering in 비떠 high vacuum and it can be used as a seed layer for the growth of C Co-contained magnetic multilayer. In this stu$\phi$, Pt thin film were epi떠xially grown on AI2D3 ($\alpha$)OJ) by RF magnetron s sputtering. The crystalline structure was analyzed by transmission electron microscope ( (TEM) and Rutherford Back Scattering (RBS)/Ion Channeling. In TEM study, Pt was b believed to be twinned on AI잉3($\alpha$)01) su$\pi$ace about Pt(ll1) plane.Moreover, RBS c channeling spectra showed that minimum scattering yield of Pt(111)/AI2O:J(1$\alpha$)OJ) was 4 4% and Pt(11J)/AI2D3($\alpha$)OJ) had 3-fold symmetry.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 1998년도 춘계학술발표회 초록집
• /
• pp.3-3
• /
• 1998

The atmospheric corrosIOn properties of Zinc (Zn) under wet/dry transition of $H_20$ film were investigated in this study. The atmospheric corrosion of metal is usually occurred as a result of repetitious thickness transition (so called wet/dry transition) of liquid phase which is covering the metal surface. Corrosion potential and the polarization behaviour of Zn during liquid film thickness transition were measured by Kelvin probe method which IS using vibrating reference electrode without touching the liquid film. The oxidized states of Zn as a result of successive wet/dry transition were also investigated by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results show that the corrosion potential and the corrosIOn rate of Zn both are increasing during drying. However, the corrOSIon rate is decreasing again when the Zn surface is completely dried while the corrosion potential still remains high. This behaviour can be explained by the polarization behaviour change of Zn according to the $H_20$ film thickness change. The completely dried surface is consisted mostly with Zn and ZnO phases. After a number of cycles of wet/dry transition, however, the oxidized Zn phase of ${\varepsilon}-Zn(OH)_2$, which has rather voluminous and defected structure, were found.

• 멤브레인
• /
• 제4권2호
• /
• pp.106-112
• /
• 1994

$ZnSo_4{\cdot}7H_2O$에 의한 모델폐수에서 Zn 농도 및 pH를 변화하여 역삼투 실험하였고, Zn용액의 pH에 따라 아연의 제거율은 상당히 변화하였고, pH 3.0~11.5 범위에서 실험한 바 pH 8.3일 때가 아연제거율은 99.9% 이상, 투과 속도는 $1.49 {\times} 10^{-3}cm/sec$로 가장 큰 값을 보였다. 아연모델폐수에 Cyanide를 아연농도와 동량으로 첨가하였을 때, 아연은 99%, Cyanide는 93% 정도 제거가 가능하였다. 또한 첨가제로 음이온계면활성제 등을 첨가하여 실험한 결과, Membrane에서의 투과속도가 $0.76 {\times} 10^{-3}cm/sec$로 현저히 감소하였다.

• 한국의류산업학회지
• /
• 제8권5호
• /
• pp.577-584
• /
• 2006

The binding of heavy metal ions onto cross-linked chitosan in dilute aqueous solution has been investigated as a function of pH (4.0 and 7.0), agitation period (10-180min) and concentration of various metal cations (5, 10, 50 and 100ppm). In order to obtain adsorbents that are insoluble and stable, and prevent the dissolution loss of chitosan into an acidic aqueous solution, chitosan flakes were cross-linked with epichlorohydrine (ECH) and its adsorption behavior was compared with that of the non cross-linked chitosan. An advantage of ECH is that it does not eliminate the cationic amine functional group of chitosan. In terms of adsorption ratio, the chitosan cross-linked at an ECH was inferior to original chitosan and was found that chitosan has a selectivity much remarkable than the cross-linked chitosan in low concentrated metal solutions. However, no significant decreases in the adsorption ratios were observed between the cross-linked ECH-chitosan and the non cross-linked chitosan concerning the adsorption of $Ni^{2+}$, $Co^{2+}$, $Pb^{2+}$ and $Zn^{2+}$ acidic solution.

• 생태와환경
• /
• 제40권4호
• /
• pp.537-545
• /
• 2007

The heavy metal removal capacity of filamentous green alga Cladophora sp. cultured together with wet-mixed solidified soil (loess) was tested. A Cladophora sp. was cultured for 5d, with added Chu No. 10 medium, in stream water contaminated by high concentration of heavy metals from a closed mine effluent. Heavy metal ion concentrations of the medium and in algal tissue were measured every day during the experiment. Dissolved metals (Al, Cd, Cu, Fe, Mn, Zn) in medium were rapidly removed (over 90% elimination) within 1-2d when alga and loess were added. Dissolved heavy metals dropped by only 10% when algae were cultured without loess. The Cladophora sp. accumulated much more heavy metals when cultured with loess than when the alga was cultured alone. Cladophora sp. exhibited a maximum uptake capacity for Al ($17,000{\mu}g^{-1}$ algal dry weight). The metal bioremoval capacities of the algae were in the order Al, Fe, Cu, Mn, Zn and Cd. The heavy metal removal capacity of Cladophora sp. showed significant increases when wet-mixed solidified soil was added to culture media.

• 한국표면공학회지
• /
• 제21권2호
• /
• pp.53-67
• /
• 1988

The high temperature corrosion of Fe-C alloys were studied at I atm SO gas in the temperature range 500~80$0^{\circ}C$ by means of a thermogravimetric analysis. The Na2SO4 induced high tempwrature corrosion rate was also measured at atm O2 gas under above the temperature renge. The reaction products were identified with the aid of X-ray diffraction technique, and micostruction of the alloy/scale interface was observed with a optical microscope and SEM. The experimental results were disussed by the themodeynamic calcutions. Under above the experimental condition. the reaction rates decrbon with increasing carbon content. The transfer of Fe ion was limited by a residue of carbon precipitated at alloy scale interface due to the oxidation of Fe-C alloys at alloy surface. The effect of cold working on reaction rate was different between the Fe containing low carbon and Fe-C Alloy containing carbon above 0,73 wt%. In a cold worked iron containing low carbon content, the crystallization of metal surface leads to the poor adherence between the alloy and the cavity formed between the alloy and scale. The outward diffusion of ion through the scale is estimated to be hindered by the cavity formed between the scale, consequently decreasing reaction rate. In the case Fe-C containing carbon above 0.73 Wt% alloy, the reaction rate was little affected by cold working, because the effect of content on reaction rats is greater than the effect of cold working.

• 방사선산업학회지
• /
• 제4권4호
• /
• pp.335-339
• /
• 2010

In this study, the surface of polyimide (PI) films was modified using ion implantation to enhance its adhesion to a deposited copper (Cu) layer. The surfaces of the PI films were implanted with 150 keV $Xe^+$ ions at fluences varying from $1{\times}10^{14}$ to $1{\time}10^{16}ions\;cm^{-2}$. The Cu layers were then deposited on the implanted PI. The surface properties of the implanted PI film were investigated based on the contact angle measurements, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). Furthermore, the adhesive strength between the deposited Cu layer and PI film was estimated through a scratch test using a nanoindenter. As a result, the surface environment of the PI film was changed by the ion implantation, which could have a significant effect on the adhesion between the deposited Cu layer and the PI.

• 공업화학
• /
• 제7권1호
• /
• pp.109-117
• /
• 1996

음이온 계면활성제의 미셀을 이용하여 한외여과막에서의 금속이온의 제거 기술은 분리공정이 간단하고 상변화가 필요없어 폐수로부터 중금속과 작은 분자량의 분자들을 제거할 수 있는 최근에 발전된 기술이다. 임계미셀농도 이상에서 계면활성제 분자들은 서로 모이고 거대분자 또는 미셀을 형성한다. 양이온의 코발트 이온과 음이온 계면활성제 미셀과의 정전기적인 결합으로 크기가 커진 거대분자가 한외여과막에서 제거되었다. 막투과압력차는 한외여과막에서의 금속의 제거율에 비교적 작은 영향을 끼치는 반면 음이온 계면활성제와 금속염간의 비(S/M)는 상당한 영향을 끼쳤다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
• /
• pp.83-83
• /
• 2008

Metal-oxide-silicon-on-insulator (MOSOI) structures were fabricated to study the effect caused by reactive ion etching (RIE) and sacrificial oxidation process on silicon-on-insulator (SOI) layer. The MOSOI capacitors with an etch-damaged SOI layer were characterized by capacitance-voltage (C-V) measurements and compared to the sacrificial oxidation treated samples and the reference samples without etching treatment. The measured C-V curves were compared to the numerical results from 2-dimensional (2-D) simulations. The measurements revealed that the profile of C-V curves significantly changes depending on the SOI surface condition of the MOSOI capacitors. The shift in the measured C-V curves, due to the difference of the fixed oxide charge ($Q_f$), together with the numerical simulation analysis and atomic force microscopy (AFM) analysis, allowed extracting the fixed oxide charges ($Q_f$) in the structures as well as 2-D carrier distribution profiles.