• Title, Summary, Keyword: self-assembly

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Fabrication of Photocatalyst Glass Beads Coated with TiO2 Thin Film by a Layer-by-Layer Process (LBL법에 의해 TiO2막이 코팅된 광촉매 글라스 비드 제조)

  • Lee, Ji-Sun;Chae, Yoo-Jin;Lee, Mi-Jai;Kim, Sei-Ki;Hwang, Jong-Hee;Lim, Tae-Young;Hyun, Soong-Keun;Kim, Jin-Ho
    • Korean Journal of Materials Research
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    • v.22 no.7
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    • pp.379-383
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    • 2012
  • $TiO_2$ thin films consisting of positively charged poly(diallyldimethylammonium chloride)(PDDA) and negatively charged titanium(IV) bis(ammonium lactato) dihydroxide(TALH) were successfully fabricated on glass beads by a layer-by-layer(LBL) self-assembly method. The glass beads used here showed a positive charge in an acid range and negative charge in an alkaline range. The glass beads coated with the coating sequence of(PDDA/TALH)n showed a change in the surface morphology as a function of the number of bilayers. When the number of bilayers(n) of the(PDDA/TALH) thin film was 20, Ti element was observed on the surface of the coated glass beads. The thin films coated onto the glass beads had a main peak of the (101) crystal face and were highly crystallized with XRD diffraction peaks of anatase-type $TiO_2$ according to an XRD analysis. In addition, the $TiO_2$ thin films showed photocatalytic properties such that they could decompose a methyl orange solution under illumination with UV light. As the number of bilayers of the(PDDA/TALH) thin film increased, the photocatalytic property of the $TiO_2$-coated glass beads increased with the increase in the thin film thickness. The surface morphologies and optical properties of glass beads coated with $TiO_2$ thin films with different coating numbers were measured by field emission scanning electron microscopy(FE-SEM), X-ray diffraction(XRD) and by UV-Vis spectrophotometry(UV-vis).

Photochromic Spiropyran-Functionalized Organic-Inorganic Hybrid Mesoporous Silica for Optochemical Gas Sensing (광화학적 가스 센싱을 위한 광변색 스피로피란 개질된 유기-무기 하이브리드 메조포러스 실리카)

  • Park, Sung Soo;Ha, Chang-Sik
    • Journal of Adhesion and Interface
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    • v.17 no.4
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    • pp.141-148
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    • 2016
  • In this work, mesoporous silica (SBA-15) was synthesized via self-assembly process using triblock copolymer ($PEO_{20}PPO_{70}PEO_{20}$, P123) as template and tetraethyl orthosilicate (TEOS) as silica source under acidic condition. SBA-15 have high surface area ($704m^2g^{-1}$) and uniform pore size (8.4 nm) with well-ordered hexagonal mesostructure. Spiropyran-functionalized SBA-15 (Spiropyran-SBA-15) was synthesized via post-synthesis process using 3-(triethoxysilyl)propyl isocyanate (TESPI) and 1-(2-Hydroxyethyl)-3,3-dimethy-lindolino-6'-nitrobenzopyrylo-spiran (HDINS). Spiropyran-SBA-15 was produced with hexagonal array of mesopores without damage of mesostructre. Surface area and pore size of Spiropyran-SBA-15 were $651m^2g^{-1}$ and 8.0 nm, respectively. Optochemical properties of Spiropyran-SBA-15 was studied with chemical vapors such as EtOH, THF, $CHCl_3$, Acetone and HCl. Main peaks of photofluorescence of Spiropyran-SBA-15 exhibited blue shift in the range of 603.4~592.1 nm after exposure under EtOH, THF, $CHCl_3$, and Acetone vapors. Normalized peak intensities decreased in the range of 0.8~0.3. The main peak of photofluorescence of Spiropyran-SBA-15 showed significant blue shift of 592.1 nm after exposure under HCl vapor, while normalized peak intensity decreased to 0.1.

Controll over the Au@Ag Core-shell Nanoparticle 2D Patterns via Diblock Copolymer Inverse Micelle Templates and Investigation of the Surface Plasmon Based Optical Property (이중블록공중합체 역마이셀 주형을 이용한 Au@Ag 코어-쉘 나노입자 2차원 패턴 제어 및 표면 플라즈몬 기반 광학적 특성 연구)

  • Yoon, Min Ji;Kim, Jihyeon;Jang, Yoon Hee;Lee, Ji-Eun;Chung, Kyungwha;Quan, Li Na;Kim, Dong Ha
    • Journal of the Korean Chemical Society
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    • v.57 no.5
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    • pp.618-624
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    • 2013
  • We demonstrated unique inter- and intra-plasmonic coupling effects in bimetallic Au@Ag core-shell NP arrays which are regularly or randomly arranged on self-assembled block copolymer (BCP) inverse micelle monolayers. Polyvinylpyrrolidone (PVP)-stabilized Au@Ag core-shell NP arrays in regular or disordered configuration were incorporated and assembled on reconstructed PS-b-P4VP inverse micelle templates through two types of processes. The intensively enhanced LSPR coupling properties of individual and assembled Au@Ag NPs were evaluated by UV-visible spectroscopy in terms of the type of ligand stabilizer, coupling between Au and Ag, thickness of Ag shell, and type of array configuration. Finally, Au@Ag core-shell NP arrays were employed as active substrates for surface enhanced Raman spectroscopy (SERS) and a significantly enhanced signal enhancement was observed in accordance with the coupling intensity of Au@Ag NPs patterns.

Development of $^{166}Ho$-Stent for the Treatment of Esophageal Cancer (식도암 치료용 $^{166}Ho$-Stent 개발)

  • Park, Kyung-Bae;Kim, Young-Mi;Kim, Kyung-Hwa;Shin, Byung-Chul;Park, Woong-Woo;Han, Kwang-Hee;Chung, Young-Ju;Choi, Sang-Mu;Lee, Jong-Doo
    • The Korean Journal of Nuclear Medicine
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    • v.34 no.1
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    • pp.62-73
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    • 2000
  • Purpose: Esophageal cancer patients have a difficulty in the intake of meals through the blocked esophageal lumen, which is caused by an ingrowth of cancer cells and largely influences on the prognosis. It is reported that esophageal cancer has a very low survival rate due to the lack of nourishment and immunity as the result of this. In this study a new radioactive stent, which prevents tumor ingrowth and restenosis by additional radiation treatment, has been developed. Materials and Methods: Using ${\ulcorner}HANARO{\lrcorner}$ research reactor, the radioactive stent assembly ($^{166}Ho$-SA) was prepared by covering the metallic stent with a radioactive sleeve by means of a post-irradiation and pre-irradiation methods. Results: Scanning electron microscopy and autoradiography exhibited that the distribution of $^{165/166}Ho\;(NO_3)$ compounds in polyurethane matrix was homogeneous. A geometrical model of the esophagus considering its structural properties, was developed for the computer simulation of energy deposition to the esophageal wall. The dose distributions of $^{166}Ho$-stent were calculated by means of the EGS4 code system. The sources are considered to be distributed uniformly on the surface in the form of a cylinder with a diameter of 20 mm and length of 40 mm. As an animal experiment, when radioactive stent developed in this study was inserted into the esophagus of a Mongrel dog, tissue destruction and widening of the esophageal lumen were observed. Conclusion: We have developed a new radioactive stent comprising of a radioactive tubular sleeve covering the metallic stent, which emits homogeneous radiation. If it is inserted into the blocked or narrowed lumen, it can lead to local destruction of the tumor due to irradiation effect with dilatation resulting from self-expansion of the metallic property. Accordingly, it is expected that restenosis esophageal lumen by the continuous ingrowth and infiltration of cancer after insertion of our radioactive stent will be decreased remarkably.

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A Study on Act on Certified Detective and Certified Detective Business (공인탐정 관련 법률(안)의 문제점과 개선방안에 관한 연구)

  • Kim, Bong-Soo;Choo, Bong-Jo
    • Korean Security Journal
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    • no.61
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    • pp.285-305
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    • 2019
  • In the bill of [Act on Certified Detective and Certified Detective Business] (hereinafter referred to as the Certified Detective Act) proposed and represented by the member of National Assembly, Lee Wan-Yong in 2017, the legislative point of view showed that various incidents and accidents, including new crimes, are frequently increasing as society develops and becomes more complex, however, it is not possible to solve all the incidents and accidents with the investigation force of the state alone due to manpower and budget, and therefore, a certified detective or private investigator are required. According to the decision of the Constitutional Court in June 2018, Article 40 (4) of the Act on the Use and Protection of Credit Information is concerned with 'finding the location and contact information of a specific person or investigating privacy other than commerce relations such as financial transactions' are prohibited. It is for the purpose of preventing illegal acts in the process of investigation such as the location, contact information, and the privacy of a specific person and protecting the privacy and tranquility of personal privacy from misuse and abuse of the personal information etc. Such 'privacy investigation business' currently operates in the form of self-employment business, which becomes a social issue as some companies illegally collect and provide such privacy information by using illegal cameras or vehicle location trackers and also comes to be the objects of clampdown of the investigative agency. Considering this reality, because it is difficult to find a resolution to materialize the legislative purpose of the Act on the use and protection of credit information other than prohibiting 'investigation business including privacy etc' and it is possible to run a similar type of business as a detective business in the scope that the laws of credit research business, security service business, the position of the Constitutional Court is that 'the ban on the investigations of privacy etc' does not infringe the claimant's freedom to choose a job. In addition to this decision, the precedent positions of the Constitutional Court have been that, in principle, the legislative regulation of a particular occupation was a matter of legislative policy determined by the legislator's political, economic and social considerations, unless otherwise there were any special circumstances, and. the Constitutional Court also widely recognized the legislative formation rights of legislators in the qualifications system related to the freedom of a job. In this regard, this study examines the problems and improvement plans of the certified detective system, focusing on the certified detective bill recently under discussion, and tries to establish a legal basis for the certified detective and certified detective business, in order to cultivate and institutionalize the certified detective business, and to suggest methodologies to seek for the development of the businesses and protect the rights of the people.