• Journal of Microbiology and Biotechnology
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• v.34 no.9
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• pp.1919-1925
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• 2024

Effective isolation and sensitive detection of Pseudomonas aeruginosa (P. aeruginosa) is crucial for the early diagnosis and prognosis of various diseases, such as urinary tract infections. However, efficient isolation and simultaneous detection of P. aeruginosa remains a huge challenge. Herein, we depict a novel fluorescence assay for sensitive, enzyme-free detection of P. aeruginosa by integrating DNAzyme cascade-induced DNA tweezers and magnetic nanoparticles (MNPs)-based separation. The capture probe@MNPs is capable of accurately identifying target bacteria and transporting the bacteria signal to nucleic acid signals. Based on the DNAzyme cascade-induced DNA tweezers, the nucleic acid signals are extensively amplified, endowing the method with a high sensitivity and a low detection limit of 1 cfu/mL. In addition, the method also exhibits a wide detection of six orders of magnitudes. The proposed method could be extended to other bacteria detection by simply changing the aptamer sequence. Taking the merit of the high sensitivity, greatly minimized detection time (less than 1.5 h), enzyme-free characteristics, and stability, the proposed method could be potentially applied to diagnosing and preventing diseases caused by pathogenic bacteria.

• Economic and Environmental Geology
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• v.38 no.2 s.171
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• pp.155-163
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• 2005

For an unbiased TF (Tansfer Function) estimations we investigate geomagnetic TF derived from ICHEON and YONGIN sites, employing RR (Remote Reference) and SNS (Signal Noise Separation) techniques. The Rh technique, which requires synchronized field variations recorded at a clean remote site, is a reliable method to minimize the bias of TF by uncorrelated noises in magnetic channels. Meanwhile, SNS technique based on the assumption of noise-free remote data can improve the signal-noise level by separating signal TF and noise TF, which is successfully applied to the environments with strong correlated noises. In this study, TF at YONGIN is analyzed using geomagnetic data from ICHEON site as a remote reference, which seem to have somewhat better data quality. The application of Rh technique reduces the bias of TF, which appears in single site robust estimation, and makes curves in the amplitude and phase of TF more smooth as frequency. Futhermore, in order to investigate noise source quantitatively, SNS technique is applied. The results of SNS suggest that dominant noise source seems to be located at western region of YONGIN. This noise source is considered to originate from railway system such as KTX and national subway. which passes through the west regions of YONGIN.

• Resources Recycling
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• v.16 no.3 s.77
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• pp.19-26
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• 2007

The bottom ash of municipal solid waste incineration generated during incineration of municipal solid waste in metropolitan area consists of ceramics, glasses, ferrous materials, combustible materials and food waste and so on. Although the ferrous material was separated by the magnetic separation before the incineration process, of which content accounts for about $3{\sim}11%$ in bottom ash. The formation of a $Fe_3O_4-Fe_2O_3$ double layer(similar to pure Fe) on the iron surface was found during air-annealing in the incinerator at $1000^{\circ}C$. A strong thermal shock, such as that takes place during water-cooling of bottom ash, leads to the breakdown of this oxidation layer, facilitating the degradation of ferrous metals and the formation of corrosion products and it existed as $Fe_2O_3,\;Fe_3O_4\;and\;FeS_2$. So, many problems could occur in the use of bottom ash as an aggregate substitutes in construction field. Therefore, in this study, the separation of ferrous materials from municipal solid waste incineration bottom ash was investigated. In the result, the ferrous product(such as $Fe_2O_3,\;Fe_3O_4,\;FeS_2$ and iron) by magnetic separator at 3800 gauss per total bottom ash(w/w.%) accounted for about 18.7%, and 87.7% of the ferrous product was in the size over 1.18 mm. Also the iron per total bottom ash accounted for about 3.8% and the majority of it was in the size over 1.18 mm.

• Investigative Magnetic Resonance Imaging
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• v.15 no.1
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• pp.57-66
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• 2011

Purpose : A new inhomogeneity correction method based on two-point Dixon sequence is proposed to obtain water and fat images at 0.35T, low field magnetic resonance imaging (MRI) system. Materials and Methods : Joint phase-magnitude density function (JPMF) is obtained from the in-phase and out-of-phase images by the two-point Dixon method. The range of the water signal is adjusted from the JPMF, and 3D inhomogeneity map is obtained from the phase of corresponding water volume. The 3D inhomogeneity map is used to correct the inhomogeneity field iteratively. Results : The proposed water-fat imaging method was successfully applied to various organs. The proposed 3D inhomogeneity correction algorithm provides good performances in overall multi-slice images. Conclusion : The proposed water-fat separation method using JPMF is robust to field inhomogeneity. Three dimensional inhomogeneity map and the iterative inhomogeneity correction algorithm improve water and fat imaging substantially.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.10
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• pp.659-665
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• 2017

When an electrically conducting fluid flows through a staggered tube bank, the heat transfer and fluid flow features are changed by the externally introduced magnetic field. This study provides a numerical investigation of this phenomenon. Heat and fluid flows are investigated for unsteady laminar flows at Reynolds numbers of 50 and 100 with the Hartmann number gradually increasing from zero to 100. As the Hartmann number increases, and owing to the effects of the introduced magnetic field, the velocity boundary layer near the tube wall is thinned, the flow separation is delayed downstream, and the shrinkage of a recirculation zone formed near the rear side is observed. Based on these thermo-fluid deformations, the resulting changes in the local and average Nusselt number are investigated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.41-41
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• 2008

제지산업은 다량의 용수를 사용하면서 또한 많은 양의 폐수를 배출하고 있다. 기존의 폐수처리 공정에서는 침전처리를 위한 큰 저수조와 오랜 침강 시간이 요구되어 제한된 공장 내에서의 처리에 어려움이 많다. 이러한 기존 기술의 문제점을 보완하면서도 새로운 고도처리가 가능한 초전도 마그네트를 이용한 자기분리 기술을 적용하고자 하였다. 자기문리의 기본 원리는 강력한 자기력에 의하여 액체에 포함된 자성입자를 분리해내는 것으로 자성입자들이 자계의 힘에 의하여 잡아당겨지고 포획됨으로서 제거되는 것이다. 자기분리용 솔레노이드 마그네트로 초전도마그네트를 적용하게 되면 아주 높은 고구배의 자장(HGMS; High Gradient Magnetic Separation) 을 발생시킬 수 있다. 초전도마그네트와 체(sieve) 형 자기필터를 이용하면 대공간에 전력손실 없이 고자장을 발생시킬 수 있기 때문에 미립자를 효과적으로 고속으로 분리하는 것이 가능해지며 또한 상자성 미세입자까지도 처리할 수 있다. 본 연구에서는 주로 유기물로 구성된 제지며|수의 부유물을 자성체와의 응집반응에 의해 플록을 형성하여 자성 플록의 자기분리 효과를 연구하였다. 자성응집반응의 특성을 평가하기 위하여 전자석 시스템을 제작하였으며 배치타입의 자기필터를 설계 제작하였다. 또한 응집제의 종류와 응집반응 공정에 따른 자성플록의 형성 정도를 조사하였으며 자기분리 후 폐수의 탁도, SS 등의 특성을 분석하였다. 그림 1은 자성응집반응의 특성을 평가하기 위하여 제작한 전자석 시스템을 나타내고 있으며 전자석의 자장해석 결과를 보이고 있다.

• Tunnel and Underground Space
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• v.27 no.5
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• pp.312-323
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• 2017

In this study, an influence of mixing ratio among firing oyster shell, non-firing oyster shell, magnetic separated converter steel slag and fly ash used as admixtures on strength properties of soil cement was evaluated by correlation analysis among compressive strength, deformation modulus and mixing ratio of admixtures. As a result, the strength of the specimens containing non-firing oyster shells was found to be larger than that of firing oyster shells, and it was confirmed that firing oyster shells could negatively affect the strength of soil cement specimens unlike previous studies. In addtion, there was a positive correlation between the ratio of magnetic separated converter slag and strength properties, so it is confirmed that it can be used as an admixture.

• Environmental Engineering Research
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• v.25 no.4
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• pp.536-544
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• 2020

To address organic dye wastewater, economic and effective adsorbents are required. Here, magnetic biochar from alkali-activated rice straw (AMBC) was successfully synthesized using one-step magnetization and carbonization method. The alkaline activation caused the large specific surface area, high pore volume and abundant oxygen-containing groups of the AMBC, and the magnetization gave the AMBC a certain degree of electropositivity and fast equilibrium characteristics. These characteristics collectively contributed to a relative high adsorption capacity of 53.66 mg g^-1 for this adsorbent towards rhodamine B (RhB). In brief, RhB can spontaneously adsorb onto the heterogeneous surface of the AMBC and reach the equilibrium in 60 min. Although the initial pH, ionic strength and other substances of the solution affected the adsorption performance of the AMBC, it could be easily regenerated and reused with considerable adsorption content. Based on the results, H-bonds, π-π stacking and electrostatic interactions were speculated as the primary mechanisms for RhB adsorption onto the AMBC, which was also demonstrated by the FTIR analysis. With the advantageous features of low cost, easy separation, considerable adsorption capacity and favorable stability and reusability, the AMBC would be a potential adsorbent for removing organic dyes from wastewater.

• Economic and Environmental Geology
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• v.35 no.2
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• pp.155-162
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• 2002

There are many typical epithermal deposits scattering in the Taran of central Kalimantan. Indonesia. To get the shallow geological information, we carried out the geophysical exploration: spontaneous potential survey, in-suite magnetic susceptibility measurement and relistivity survey method in this area for a few weeks from September 30th to October 27th in 1997. SP survey (Fluke 27 multimeter)/magnetic susceptibility (EK -7 meter) measurement was carried out with a 250m$\times$10m lattice net in N45$^{\circ}$W direction. The dipole-dipole array resistivity survey was conducted with an electrode spacing of ${\alpha}$=30 m and electrode separation index n=7 at the line 5. The result shows that was the gold bearing quartz vein area can be divided into two type lone: low sulfidation type and high sulfidation type zone. The low resistivity value in the survey line 5 indicated a fracture Bone associated with the high sulfidation zone.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.298-298
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• 2008

제지산업은 다량의 용수를 사용하면서 또한 많은 양의 폐수를 배출하고 있다. 기존의 폐수처리 공정에서는 침전처리를 위한 큰 공간과 오랜 시간이 요구되어 처리비용이 비교적 많이 드는 단점이 있다. 이러한 기존 기술의 문제점을 보완할 수 있는 새로운 고도처리가 가능한 초전도 마그네트를 이용한 자기분리 기술을 적용하고자 하였다. 자기분리의 기본 원리는 강력한 자기력에 의하여 액체에 포함된 자성입자를 분리해내는 것으로 자성입자들이 자계의 힘에 의하여 잡아당겨지고 포획될으로서 제거되는 것이다. 자기분리용 전자석으로서는 아주 이상적으로 이러한 초전도마그네트와 체(sieve) 형 자기필터를 결합시키면 아주 높은 고구배의 자장(HGMS; High Gradient Magnetic Separation)을 발생 시킬 수 있다. 초전도마그네트를 이용하면 대공간에 전력손실 없이 고자장을 발생시킬수 있기 때문에 미립자를 효과적으로 고속으로 분리하는 것이 가능해지며 또한 상자성 미세입자까지도 처리할 수 있다. 본 연구에서는 주로 유기물로 구성된 제지며|수의 부유물을 자성체와의 응집반응에 의해 플록을 형성하여 자성플록의 자기분리 효과를 연구하였다. 응집제의 종류와 응집반응 공정에 따른 자성플록의 형성 정도를 조사하였으며 자기분리 후 폐수의 탁도, COD 등의 특성을 분석하였다.