• 한국건설순환자원학회논문집
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• 제9권1호
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• pp.92-99
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• 2021

CaO 화합물의 원료로는 일반적으로 CaO, SO3, Al2O3 등으로 구성된 CaO 기반인 산업부산물이 있다. 이러한 CaO 계 산업부산물을 레미콘의 회수수에 적용할 경우 시멘트, 플라이애시, 슬래그미분말 등의 콘크리트 분말 원료의 수화 반응이 가속화되어 콘크리트 성능을 향상시킬 수 있다. 본 연구에서는 레미콘의 회수수에 C12A7을 함유한 열연 슬래그를 혼입하여 레미콘의 회수수에 적용할 수 있는 활성슬러지를 제조하였으며, 시멘트 페이스트 응결시간 및 모르타르 압축강도 성능 테스트를 통해 수화반응에 대한 영향을 확인하고자 하였다.

• 한국건설순환자원학회논문집
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• 제8권4호
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• pp.395-403
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• 2020

CaO원 산업부산물은 CaO, SO3 및 Al2O3 등으로 구성되어 있어 CaO 화합물의 원료로 사용되고 있다. 이러한 CaO원 산업부산물을 레미콘 회수수에 적용할 경우 슬러지수의 pH를 높여주어 콘크리트 분말 원료의 수화 반응을 촉진하여 콘크리트 조직을 치밀하게 하여 성능 향상이 가능할 것이다. 본 연구에서는 레미콘 회수수에 CaO원 산업부산물 중 하나인 탈황석고를 혼입하여 제조된 활성슬러지의 효과를 확인하기 위해 콘크리트의 특성을 분석하였다. 그 결과 콘크리트에 대한 시험 결과 작업성을 확보하면서 강도 및 건조수축에 대한 문제점이 없는 것을 확인할 수 있었으며, 활성슬러지를 이용한 콘크리트 적용에 대한 가능성을 확인할 수 있었다.

• 한국산업보건학회지
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• 제32권4호
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• pp.359-370
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• 2022

Objective: This study is intended to design a commercially available passive sampler and conduct performance test on its use as a media for evaluating a working environment. Methods: This study was conducted to select adsorbents, design models, and evaluate storage stability and sampling rates for the development of new types of passive samplers. Results: The impurity detection, adsorbent capacity and breakthrough volume of five types of activated carbon were tested for selection of an adsorbent. One product was selected in consideration of the efficiency of purchase. A number of passive samplers were designed in a radial style and a badge style using plastic as a material. The final two prototypes were made using molds or 3D printing. For the storage stability evaluation, samples were stored at different temperature for 1~21 days and then analyzed. Most of the chemicals had excellent storage stability when refrigerated. However, some chemicals such as dichloromethane and methyl ethyl ketone need to be analyzed as soon as possible after sampling. Conclusion: In this study, new types of passive samplers for 66 chemical compounds were developed. The evaluation of storage stability and sampling rates showed different results depending on the properties of the chemical substance. For some chemicals such as methyl ethyl ketone and dimethylformamide, activated carbon is inappropriate as an absorbent. In future studies, additional experiments are required on chemicals that are difficult to collect with activated carbon.

• 공업화학
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• 제35권4호
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• pp.352-359
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• 2024

Environmental pollution from heavy metal ions (HMIs) is a global concern. Recently, biosorption methods using cellulose sorbents have gained popularity. The objective of this study was to assess the removal efficiency of Cu(II), Pb(II), and Hg(II) ions at low concentration levels (100-700 ppb) from aqueous solutions using three different cellulose fiber-based filter media. Sample A was pure cellulose fiber, Sample B was 10% activated carbon-cellulose fiber, and Sample C was cellulose fiber-glass fiber-30% activated carbon-20% amorphous titanium silicate (ATS). The samples were characterized by several physicochemical techniques. The porosity measurements using N₂ sorption isotherms revealed that Samples A and B are nonporous or macroporous materials, whereas the addition of 50% filler materials into the cellulose resulted in a microporous material. The Brunauer-Emmett-Teller (BET) surface area and pore volume of Sample C were found to be 320.34 m²/g and 0.162 cm³/g, respectively. The single ion batch adsorption experiments reveal that at 700 ppb initial metal ion concentration, Sample A had removal efficiencies of 7.5, 11.5, and 13.7% for Cu(II), Pb(II), and Hg(II) ions, respectively. Sample B effectively eliminated 99.6% of Cu(II) ions compared to Pb(II) (14.2%) and Hg(II) (31.9%) ions. Cu(II) (99.37%) and Pb(II) (96.3%) ions are more efficiently removed by Sample C than Hg(II) (68.2%) ions. The X-ray photoelectron spectroscopy (XPS) wild survey spectrum revealed the presence of Cu(II), Pb(II), and Hg(II) ions in HMI-adsorbed filter media. The high-resolution C1s spectra of Samples A and B reveal the presence of -C-OH and -COOH groups on their surface, which are essential for HMIs adsorption via complexation reactions. Additionally, the ATS in Sample C facilitates the adsorption of Pb(II) and Hg(II) ions through ion exchange.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.199-199
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• 2009

Recently, polymeric microlens arrays have become important elements in many applications. Microlens arrays have been used to enhance luminance efficiency and luminance power efficiency of light-emitting diodes (LEDs) and organic LEDs. Many processes for fabrication of microlens array are studied. Though the MLA has been fabricated by electroformed mold, LIGA process and reflow method, these methods were required masks, multiple process steps and post processing. In this paper, we proposed rapid and direct UV laser direct fabrication process using colorless liquid photopolymer, NOA60 for polarization activated microlens. The microlens arrays are formed on the NOA60 on glass, after the focused laser energy was irradiated to the material. The diameter of MLA was varied from 42 to 88 ${\mu}m$, and the height from 0.9 to 1.6 ${\mu}m$. The MLA fabricated using NOA60 shows more then 85% transmittance as well as good hardness for optical module.

• 상하수도학회지
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• 제22권1호
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• pp.3-14
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• 2008

ASM No. 2(Activated sludge model No. 2) is very useful model to analyze the wastewater treatment which removes nitrogen and phosphorus. But, it is difficult to apply ASM No. 2 to control of wastewater treatment since it has 17 material divisions and 46 parameters. So the purpose of this study was the simplification of ASM No. 2 and the provement of simplification model. Firstly ASM No. 2 was simplified with 5 material division and three phases(Anaerobic, aerobic, anoxic phases). The simplified model was proved by R-square using track study data. As a result of provement, the values of R-square in ${NH_4}^+$ were 0.9815 in ASM No. 2 and 0.9250 in simplified model and in ${NO_3}^-$ were 0.8679 in ASM No. 2 and 0.7914 in simplified model and in ${PO_4}^{3-}$ are 0.9745 in ASM No. 2 and 0.9187 in the simplified model when the ability to express the material variation was compared by R-square. So, the simplified model has enough ability to express the variation of ${NH_4}^+$, ${NO_3}^-$ and ${PO_4}^{3-}$.

• 건축역사연구
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• 제14권1호
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• pp.107-122
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• 2005

The purpose of this study is to analyse Herzog & de Meuron's surface, which represents contemporary architectural trends toward surface. Semper's Bekleidung theory and the important architectural theories about surface were compared according to the conceptual opposition between representation and re-presentation, which is borrowed from Kastern Harris, and again Martin Heidegger. Representation means a sort of translation into a different medium. It doesn't preserve the material identity of what it represent. Re-presentation, however, celebrates the material employed. The tension between representation and re-presentation have activated the architectural history Contemporary architects have emphasized re-presentation at the expense of representation. This trends relate with digital technology, which demands surface or skin independent from depth or interior. Buildings that deserve to be called works of architecture invite us to attend to material in a different way Re-presenting its materials, the work of architecture reveals its being. Such revelation requires that materials work in a way that invites us to step back from our usual involvement with things. It's the poetics of re-presentation, which is emboded in the Herzog & de Meuron's architectural works.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 디스플레이 광소자분야
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• pp.151-154
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• 2003

The synthesis and luminescent properties of trivalent europium activated gadolinium oxide red phosphors by sol-gel process have been investigated. Aqueous metal nitrate solution was mixed with EDTA which was chosen by the most suitable material of sol-gel formation as chelating agents. We noticed that the samples when are heated with EDTA at a temperature of $100^{\circ}C$ for lhrs, produced brownish and crisp powders due to condensation reaction on decomposition, dehydration and formation of sol-gel. Hence, when the powder pre-heated at about $100^{\circ}C$ was then heated at $1200^{\circ}C$ for 3hrs in atmosphere, the luminescence properties of resultant $Gd_{2}O_{3}:Eu^{3+}$ phosphor was measured by SEM, FT-IT and brightness intensity was shown 20% higher than those prepared by conventional method and by other chelating agent.

• 한국전기전자재료학회논문지
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• 제17권9호
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• pp.973-978
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• 2004

This work describes the effect of conducting materials on the electrochemical performances of electric double layer capacitor. Three kinds of Carbon black, such as Acethylene Black, Super P Black, Ketjen black supplied by Denki Kagaku Kogyo, MMM Carbon, Ketjen Black International Co. respectively, was added in carbon-Polytetrafluoroethylene (PTFE) electrode, which composition is activated carbon : carbon black : PTFE = 80 : 15 : 5 wt.%, and were compared with their electrochemical properties. The electrode with Ketjen Black has showed the lowest resistance than other carbon black, and also exhibited the better rate capability between 0.5 mA/cm$^2$ ∼ 100 mA/cm$^2$ current density in unit cell capacitor. On the other hand, as increasing the composition of Ketjen Black, the specific resistances of electrodes were decreased and Ketjen Black content higher than 15 wt% increased. The best rate capability was obtained at the electrode with 15 wt.% of Ketjen Black in unit cell capacitor. This behaviors would be correlated with the dense structure of electrode.

• 대한의용생체공학회:의공학회지
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• 제30권3호
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• pp.199-204
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• 2009

Iridium oxide films (IROFs) have been extensively studied as a material for electrical stimulation of neurons, as iridium oxide has higher charge storage capacity than other metal films. More recently, sputtered iridium oxide film (SIROF) has been studied, because it can be made more conveniently than activated iridium oxide film (AIROF). Typically, the SIROFs are grown at temperatures from 400 to 600 $^{\circ}C$. However, such high temperatures cannot be used when the iridium oxide (IrOx) film is to be deposited on a flexible polymer material, such as polyimide. In this paper, we show that we can still obtain excellent characteristics in SIROFs grown without heating (cold SIROF), by optimizing the growth conditions. We show that the oxygen flow rate is a critical parameter for controlling the surface properties of a cold SIROF. At an oxygen flow rate of 12 seem, the cold SIROF exhibited a charge storage capacity (CSC) of 60 mC/cm$^2$, which is comparable to or better than other published values for iridium oxide films including heated SIROFs. The film produced under these conditions also had the minimum impedance value of all cold SIROFs deposited for this study. A stability test and biocompatibility test also demonstrated the superiority of the optimized cold SIROF.