• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.186-187
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• 2003

최근 들어 단일 양자점이나 단일 분자에 대한 분광 연구가 매우 관심을 끌고 있는데, 이는 미세구조 물질의 근본 물성을 밝히고자 하는 물리적인 관점뿐만 아니라 이를 실제적으로 이용하려는 실용적인 관점에서도 매우 중요한 주제이기 때문이다. 그러나 단일 양자점이나 단일 분자의 분광을 위해서는 공간적인 분해능이 우수할 뿐만 아니라 그 계에서 나오는 매우 미약한 광 신호를 검출하여야 하는 고도의 기술이 필요하다. (중략)

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.153-153
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• 2000

Si 산화는 반도체 공정상 필요한 과정으로 산업적으로나 학문적으로 중요하고 많이 연구되었다. 이중에서 Si(1110-7x7표면에서 초기 흡착된 산소는 준안정적 상태로 존재하며 표면온도, 산소의 노출량 그리고 진공도에 따라 그 수명이 제한된다. 이러한 준안정적 상태의 산소의 화학적 성질은 여러 표면분석장비가 동원되어 연구되었으나 아직까지 논쟁이 되고 있다. 이 경우 산소가 어떤 상태로 존재하는가는 표면화학종을 검출함으로서 해결될 수 있다. 저에너지 Cs+ 이온 반응성 산란은 이러한 요구를 충족시킬수 있는 가장 적합한 실험 방법중의 하나이다. 저에너지 Cs+ 이온 산란의 특징 중의 하나는 입사된 Cs+ 이온이 표면에 흡착된 화학종과 충돌후 탈착되면서 반응을 하여 송이 이온을 형성한다는 것이다. 이 송이 이온을 관측함으로서 표면에 존재하는 화학종을 알아 낼 수 있다. 이에 산소가 흡착된 Si(111)-7x7 표면에서의 산소의 준안정적 상태가 저에너지 Cs+ 이온 산란 실험을 통하여 연구되었다. 실험은 0.2-2L(1Langmuir = 10-6 Torr x 1 sec) 산소 노출량과 -15$0^{\circ}C$ - $25^{\circ}C$의 표면온도 그리고 5eV - 20eV의 Cs+ 이온 충돌에너지에서 CsSiO+ 이온이 유일한 생산물로서 검출되었다. CsSiO+ 이온은 입사된 Cs+ 이온과 표면에 존재하는 SiO 분자가 충돌 후 반응하여 탈착된 것으로 생각된다. 이것은 낮은 산소 노출량 즉, 초기 산화 단계에서 SiO가 표면에 존재한다는 것을 의미한다. 즉, 산소 분자는 산화단계의 초기에 해리되어 표면에 흡착되고 선구물질인 SiO를 형성함을 제시한다. 최근의 이론적 계산인 density functional calculation에서도 산소분자가 Si(111)-7$\times$7 표면의 준안정적 산화상태의 선구물질일 가능성을 배제한다. 이는 본 저에너지 Cs+ 이온 반응성 산란실험을 뒷받침하는 계산 결과이다. 높은 Cs+ 이온 충돌에너지에서 CsSi+, Si+, SiO+, Si2+, Si2O+ 등이 추가로 검출되었다. 이는 CsSi 이온을 제외하고 수 keV의 충돌에너지를 사용하는 이차 이온 질량 분석법과 비슷한 결과이다.

• Analytical Science and Technology
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• v.17 no.4
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• pp.337-346
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• 2004

7-keto-dehydroepiandrosterone-acetate (7-keto-DHEA-acetate) is an anabolic steroids, and we studied basically to the metabolites of it after human dosing. We tested the matrix effect from human urine to detect the 7-keto-DHEA-acetate. And LC/ESI/MS and GC/MSD was used to detect the metabolites in dosed urine. We found the some unknown compound from dosed urine (M1, M2, M3, M4 and M5), and from these results, we supposed that these compounds have the more than 3 hydroxyl and/or ketone group. Metabolite M1 was supposed that molecular weight is 302 and 3-,17-diketone and 7-hydroxyl compound (7-OH-androstendione). Metabolite M2 was supposed that the molecular weight was same to M1 and 7-,17-diketone and 3-hydroxyl compound (7-keto-DHEA).

• Applied Chemistry for Engineering
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• v.30 no.2
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• pp.186-189
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• 2019

Polypyrrole is a typical electrical conducting polymer, which has an excellent charge transport property. Cyclodextrins are a group of toxic-free and cyclic oligosaccharide molecules, capable of capturing low molecular weight chemicals. Considering these advantages, hybrid materials of polypyrrole and cyclodextrin can be used to detect hazardous compounds. Cyclodextrin molecules can accommodate toxic chemicals by the formation of host-guest complexes and generate electric signals, which are effectively delivered by polypyrrole backbone. In this study, the polypyrrole/cyclodextrin hybrid material was prepared using a facile wet method and included into a hydrogel. Subsequently, it was applied to a simple sensor system with a gold-patterned electrode for the detection of potentially hazardous material, methyl paraben. Compared with pristine polypyrrole, it was found that the polypyrrole/cyclodextrin hybrid showed an improved performance. This study can be an example of using environmentally benign conducting polymer/cyclodextrin hybrids as sensing media.

• Journal of Life Science
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• v.26 no.5
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• pp.620-631
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• 2016

Viroids are about 250-400 base pair of short single strand RNA fragments have been associated with economically important plant diseases. Due to the lack of protein expression capacity associated with replication, it is very difficult to diagnosis viroid diseases in serological methods. For detecting viroid at plants, molecular-based techniques such as agarose gel electrophoresis, polyacrylamide gel electrophoresis (PAGE), DNA-hybridization, blotting analysis and conventional RT-PCR are reliable. Real-time RT-PCR methods that grafted on RT-PCR methods with improved confirmation methods have been also utilized. However, they are still labor-intensive, time-consuming, and require personnel with expertise. Loop-mediated Isothermal Amplification (LAMP) method is a nucleic acid amplification method under the isothermal condition. The LAMP methodology has been reported to be simple, rapid, sensitive and field applicable in detecting a variety of pathogens. The results of LAMP method can be colorized by adding a visible material such as SYBR green I, Evagreen, Calcein, Berberine and Hydroxy naphthol blue (HNB) with simple equipment or naked eyes. The combination of LAMP method and nucleic pathogens, viroids, can be used to realize simple diagnosis platform for the genetic point-of care testing system. The aim at this review is to summary viroid-caused diseases and the simple visible approach for diagnosing viroids using Loop-mediated Isothermal Amplification (LAMP) method.

• Journal of Apiculture
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• v.34 no.1
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• pp.15-26
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• 2019

Tracheal mite (Acarapis woodi) is an internal parasite that is parasitic on the bronchus of adult bees and sucks fluid from the trachea. Since its first report by Rennie, it has been spread throughout Europe and in some Asian regions, with adjacent Japan and China reported in 2011 and 2012, respectively. Korea detected specific genes of A. woodi in 2015, but only one of 99 samples has been identified and the being of A. woodi has not been confirmed. In this study, we established a specific nested PCR method to confirm for detecting low-copy number of A. woodi-specific gene in bee samples. As a result, A. woodi-specific COI gene was amplified in 15 of 23 samples, and they were judged positive by melting point analysis and sequencing analysis. Although we could not observe the existence of the mites in bees, our results suggest that tracheal mit might exist in nature.

• Polymer(Korea)
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• v.24 no.3
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• pp.306-313
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• 2000

Polycaprolactone (PCL) macromer containing terminal methacrylate group was synthesized by ring-opening polymerization. The number average molecular weight of PCL macromer was 11600 g/mole and polydispersity index was 1.09. The synthesized PCL macromer was copolymerized with styrene by stable free radical polymerization using 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO), benzoyl peroxide, and well-defined poly(styrene-g-caprolactone)s were synthesized. The synthesized copolymers was characterized by $^1$H-NMR and gel permeation chromatography equipped with multiangle laser light scattering detector. Thermal properties of graft copolymers were investigated by DSC.

• Journal of the Korean Chemical Society
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• v.21 no.3
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• pp.215-218
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• 1977

We have investigated for amino acid composition, molecular weight and terminal amino acid of the main gliadin protein which was purified by Sephadex column. The results were obtained as follows: 1. The highest content of amino acid was glutamic acid for the main gliadin protein. 2. The molecular weight was estimated 60,200 ${\pm}$200 for the main gliadin protein. 3. Identified N-terminal and C-terminal amino acid of the main gliadin protein were phenylalanine and methionine, respectively.

• Journal of the Korean Vacuum Society
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• v.20 no.6
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• pp.409-415
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• 2011

The method to improve the detection sensitivity of Hand-held XRF (X-Ray Fluorescence) device currently being developed is discussed. To minimize the loss of the intensity due to atmospheric gas molecules, the vacuum module, which can be filled with atmospheric or He gas, between the sample and the detector was installed. And the change of the detection sensitivity was measured in a vacuum and in the He gas-filled state. As a result, the following three important results were obtained; Firstly, XRF intensity was increased 2~4 times in the low energy range (3~4 keV). It is a very important result because the enhancement of the detection sensitivity means shortening of the detection time in Hand-held XRF device. Secondly, the possibility of detection of the elements less than 3 keV in emission energy was confirmed. Thirdly, the absorption by atmospheric gas molecules can be minimized without vacuum- sealed vessel in Hand-held XRF device, if the vacuum module filled with He gas is used. We concluded that all of three results are very meaningful in the development of a Hand-held XRF device.

• The Journal of the Korea Contents Association
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• v.19 no.2
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• pp.259-268
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• 2019

Dengue virus is a typical mosquito-borne virus, and the half of the world's population is exposed to infection. Dengue virus causes relatively mild symptoms such as dengue fever. However, when not treated properly, it is known to cause severe symptoms such as dengue hemorrhagic fever and dengue shock syndrome with a mortality rate of over 20%. Development of dengue virus detection technology is very important because it is reported that early diagnosis of dengue fever can lower the mortality rate to less than 1%. In this study, patent search related to dengue virus detection technology was conducted in Korea, USA, Europe, Japan, and China. The quantitative analysis of 69 validated patents from the searched patents was conducted by country, year, and patent holder. In addition, in-depth analysis was carried out by classifying into three categories: molecular diagnostics, immuno-diagnostics, and cell culture-based diagnostics from all validated patents. From these results, we analyzed the patent trend related to dengue virus detection and dengue fever diagnosis technology and discussed the features and limitations of molecular diagnostics and immuno-diagnostics at present level. Furthermore, we discussed the direction of technology development and future prospects to overcome limitations.