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Detection of benzalkonium chloride on glass surfaces using silver nanoparticles
Nguyễn Hoàng Ly,Phuong-Dong Nguyen,Sang Jun Son,이철민,Soonmin Jang,주상우,Kyungjoo Kim,Jiseon Choi,Ye-eun Joo,Jung Il Lee 대한화학회 2022 Bulletin of the Korean Chemical Society Vol.43 No.2
Raman reporter-based surface-enhanced Raman scattering (SERS) has been used to investigate the detection of one member of a class of the cationic surfactant quaternary ammonium compounds, alkyl dimethyl benzyl ammonium chloride, also known as benzalkonium chloride (BAC). For this study, SERS was performed using silver nanoparticles (AgNPs). Density functional theory (DFT) of BAC on Ag6 clusters was introduced to estimate binding at the level of the B3LYP/LANL2DZ basis sets. As the chain length increased from n = 8 to 18, the binding energies were expected to increase by 2.1 kcal/mol. Methylene blue (MB) Raman reporter molecules were subsequently treated on BAC thin-film-covered glass surfaces. Atomic force microscopy (AFM) images were used to determine the coverage of BAC on the glass, and field-emission electron microscope (FE-SEM) images revealed the surface morphologies of the SERS substrates. A standard calibration curve was prepared to quantify BAC within a concentration range of 0.0036805 to 36?805?ppm (r2?≥?0.99), according to the BAC-correlated SERS intensities of MB Raman peaks at ~1620?cm?1 adsorbed on AgNPs. A molecular dynamics (MD) simulation supported strong adsorption of BAC on glass surfaces.
Improve performance of plate heat exchanger by electrochemical etching
Dong Ho Nguyen,Koung Moon Kim,Gyu Hyeon Shim,Ho Seon Ahn 대한기계학회 2020 대한기계학회 춘추학술대회 Vol.2020 No.12
In this research, electrochemical etching method was applied on plate heat exchanger surface to improve thermal-hydraulic performance. The enhancement was analyzed through experimental data regarding the overall heat transfer coefficient (OHTC), friction factor and performance of evaluation criterion (PEC) of water flow inside a plate heat exchanger (PHE). A series of etching cases was conducted in order to find the optimal conditions for an application on commercial stainless steel 304 corrugated plates with a symmetrical chevron angle of 30<SUP>0</SUP>. The etching experiment using aqua Regia solution of the volumetric ratio of 1:3:175 (HNO₃: HCl: H₂O, respectively), was conducted on the as-received surface resulting in a significant increase in Ra value and static contact angle. As a consequence of PHE experiments, the OHTC improved to 11-17%, and PEC valued from 1.08 to 1.19, while an unavoidable increase of friction factor by at least 20%.
Nguyen, Nguyen Ngan,Jo, Sae Byeok,Lee, Seong Kyu,Sin, Dong Hun,Kang, Boseok,Kim, Hyun Ho,Lee, Hansol,Cho, Kilwon American Chemical Society 2015 NANO LETTERS Vol.15 No.4
<P>A two-dimensional epitaxial growth template for organic semiconductors was developed using a new method for transferring clean graphene sheets onto a substrate with controlled surface wettability. The introduction of a sacrificial graphene layer between a patterned polymeric supporting layer and a monolayer graphene sheet enabled the crack-free and residue-free transfer of free-standing monolayer graphene onto arbitrary substrates. The clean graphene template clearly induced the quasi-epitaxial growth of crystalline organic semiconductors with lying-down molecular orientation while maintaining the “wetting transparency”, which allowed the transmission of the interaction between organic molecules and the underlying substrate. Consequently, the growth mode and corresponding morphology of the organic semiconductors on graphene templates exhibited distinctive dependence on the substrate hydrophobicity with clear transition from lateral to vertical growth mode on hydrophilic substrates, which originated from the high surface energy of the exposed crystallographic planes of the organic semiconductors on graphene. The optical properties of the pentacene layer, especially the diffusion of the exciton, also showed a strong dependency on the corresponding morphological evolution. Furthermore, the effect of pentacene–substrate interaction was systematically investigated by gradually increasing the number of graphene layers. These results suggested that the combination of a clean graphene surface and a suitable underlying substrate could serve as an atomically thin growth template to engineer the interaction between organic molecules and aromatic graphene network, thereby paving the way for effectively and conveniently tuning the semiconductor layer morphologies in devices prepared using graphene.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2015/nalefd.2015.15.issue-4/nl504958e/production/images/medium/nl-2014-04958e_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl504958e'>ACS Electronic Supporting Info</A></P>
Enzyme-mediated fabrication of an oxidized chitosan hydrogel as a tissue sealant
Phuong, Nguyen Thi,Anh Ho, Viet,Hai Nguyen, Dai,Khoa, Nguyen Cuu,Quyen, Tran Ngoc,Lee, Yunki,Park, Ki Dong Technomic Pub. Co 2015 Journal of bioactive and compatible polymers Vol.30 No.4
<P>Oxidized polysaccharide-based hydrogels have recently attracted much attention for tissue regeneration because of their biocompatibility and tissue-adhesive property. In this study, we introduce a new type of chitosan-based hydrogel as a tissue sealant, which was prepared by enzymatic mediation from periodate-oxidized chitosan–polyethylene glycol–tyramine. The oxidized chitosan backbone was expected to enhance the interconnection between the hydrogel layer and collagen in the tissues via the Schiff-base reaction. Proton nuclear magnetic resonance spectra indicated that tyramine-functionalized polyethylene glycol-nitrophenyl carbonate ester was conjugated to the oxidized chitosan. The degree of oxidation of the chitosan backbone was around 14% of the glucosamine units by proton nuclear magnetic resonance. The hydrogel was rapidly formed in situ (within a few seconds) in the presence of horseradish peroxidase and hydrogen peroxide. In vitro experiments with live/dead cell assays showed that the oxidized chitosan-based hydrogel was cytobiocompatible. The hydrogel exhibited high tissue adhesion strength on porcine skin models as well as good tissue-adhesive ability and wound healing properties on rabbit skin. These positive results could be promising for the application of oxidized chitosan-based hydrogels as a wound sealant.</P>
Solar-powered multi-scale sensor node on Imote2 platform for hybrid SHM in cable-stayed bridge
Ho, Duc-Duy,Lee, Po-Young,Nguyen, Khac-Duy,Hong, Dong-Soo,Lee, So-Young,Kim, Jeong-Tae,Shin, Sung-Woo,Yun, Chung-Bang,Shinozuka, Masanobu Techno-Press 2012 Smart Structures and Systems, An International Jou Vol.9 No.2
In this paper, solar-powered, multi-scale, vibration-impedance sensor node on Imote2 platform is presented for hybrid structural health monitoring (SHM) in cable-stayed bridge. In order to achieve the objective, the following approaches are proposed. Firstly, vibration- and impedance-based hybrid SHM methods are briefly described. Secondly, the multi-scale vibration and impedance sensor node on Imote2-platform is presented on the design of hardware components and embedded software for vibration- and impedance-based SHM. In this approach, a solar-powered energy harvesting is implemented for autonomous operation of the smart sensor nodes. Finally, the feasibility and practicality of the smart sensor-based SHM system is evaluated on a full-scale cable-stayed bridge, Hwamyung Bridge in Korea. Successful level of wireless communication and solar-power supply for smart sensor nodes are verified. Also, vibration and impedance responses measured from the target bridge which experiences various weather conditions are examined for the robust long-term monitoring capability of the smart sensor system.
Dong, Nguyen-Thanh,Bae, Ki-Hwan,Kim, Young-Ho,Hwang, Gwi-Seo,Heo, Ok-Soon,Kim, Se-Eun,Kang, Jong-Seong The Pharmaceutical Society of Korea 2003 Archives of Pharmacal Research Vol.26 No.7
A reversed-phase high performance liquid chromatographic method was developed to determine the contents of psoralen and angelicin from some medicinal herbs. The optimum eluent for chromatography was 20 v/v% acetonitrile in water on a Zorbax 300SB $C_{18}$ column. The identification was carried out by comparing the retention time and mass spectra of the relevant peaks with their standards. The variation of the concentration of psoralen and angelicin was wide between different species. The seeds of Psoralea corylifolia showed the highest contents of psoralen (7.8 mg/g) and angelicin (2.3 mg/g) among the tested herbs.
Verification of the Theoretical Model for Analyzing Dynamic Behavior of the PIG from Actual Pigging
Dong Kyu Kim,Sung Ho Cho,Seoung Soo Park,Yong Woo Rho,Hui Ryong Yoo,Tan Tien Nguyen,Sang Bong Kim 대한기계학회 2003 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.17 No.9
This paper deals with verification of the theoretical model for dynamic behavior of Pipeline Inspection Gauge (PIG) traveling through high pressure natural gas pipeline. The dynamic behavior of the PIG depends on the differential pressure across its body. This differential pressure is generated by injected gas flow behind the tail of the PIG and expelled gas flow in front of its nose. To analyze the dynamic behavior characteristics such as gas flow in pipeline, and the PIG position and velocity. not only the mathematical models are derived, but also the theoretical models must be certified by actual pigging experiment. But there is not any found results of research on the experimental certification for dynamic behavior of the PIG. The reason is why the fabrication of the PIG as well as, a field application are very difficult. In this research, the effectiveness of the introduced solution using the method of characteristics (MOC) was certified through field application. In-line inspection tool, 30" geometry PIG. was fabricated and actual pigging was carried out at the pipeline segment in Korea Gas Corporation (KOGAS) high pressure system. Incheon LT (LNG Terminal)-Namdong GS(Governor Station) line. Pigging is fulfilled successfully. Comparison of simulation results with experimental results show that the derived mathematical models and the proposed computational schemes are effective for predicting the position and velocity of the PIG with a given operational conditions of pipeline.