• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.2
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• pp.115-125
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• 2010

In order to design the optimal escape vent for the coon strip shrimp pot, the tank experiments were conducted with the model pot of five different slit height and slit width, respectively. The optimal height and width of escape vent were determined to 20mm and 40mm by tank experiments, respectively. These were determined by the 50% selection carapace length which was denoted to 25mm in selectivity curve. The escape experiments were conducted to determine a number of escape vent with the original shrimp pot to be set the designed escape vent from 2 vents to 10 vents increasing at intervals of 2 vents in tank. The optimal number of escape vents denoted 8 vents. Therefore, to apply the escape vent in commercial shrimp pot will be efficient to reduce small size shrimps to catch.

• Membrane Journal
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• v.29 no.4
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• pp.202-215
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• 2019

Molecular sieve membranes separate molecules based on their size and/or shape and have been of high interest, due to their potentially high energy efficiency and high selectivity. Zeolite MFI membrane is one of the most-studied molecular sieve membranes and has affected following studies on other molecular sieve membranes. This review discusses the technical developments on the control of morphology, microstructure, and defect of MFI membranes, which have significantly improved xylene isomer separation performances. These include crystal morphology control, effective secondary growth, seed coating method, crystal orientation control, heteroatom doping, and defect healing method.

• Current Applied Physics
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• v.18 no.11
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• pp.1255-1260
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• 2018

In this work, a green and simple one-pot route was developed for the synthesis of highly fluorescent aminofunctionalized graphene quantum dots (a-GQDs) via hydrothermal process without any further modification or surface passivation. We synthesized the a-GQDs using glucose as the carbon source and ammonium as a functionalizing agent without the use of a strong acid, oxidant, or other toxic chemical reagent. The as-obtained aGQDs have a uniform size of 3-4 nm, high contents of amino groups, and show a bright green emission with high quantum yield of 32.8%. Furthermore, the a-GQDs show effective fluorescence quenching for $Cu^{2+}$ ions which can serve as effective fluorescent probe for the detection of $Cu^{2+}$. The fluorescent probe using the obtained aGQDs exhibits high sensitivity and selectivity toward $Cu^{2+}$ with the limit of detection as low as 5.6 nM. The mechanism of the $Cu^{2+}$ induced fluorescence quenching of a-GQDs can be attributed to the electron transfer by the formation of metal complex between $Cu^{2+}$ and the amino groups on the surface of a-GQDs. These results suggest great potential for the simple and green synthesis of functionalized GQDs and a practical sensing platform for $Cu^{2+}$ detection in environmental and biological applications.

• Membrane Journal
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• v.10 no.4
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• pp.192-197
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• 2000

Gas permeation and separation characteristics of ozone treated polysulfone (PSF) membranes were investigated. The PSF is one of the most widely used commercial membranes. Ozone treatment of the PSF membrane was performed for certain hours by continuously supplying 5 vol.% ozone-containing oxygen to the chamber, in which the membrane samples were charged. The permselectivity of PSF increased with ozone treatment time, and it was found that one and half hour was enough to ozone treatment. Increase in the selectivity of the membrane for He/$N_2$, HY$N_2$, O:J$N_2$, COJ$CH_4$ by ozone treatment was found to be due to decrease in the permeability of gases with larger molecular size such as $N_2$ and $CH_4$ The decrease in the permeability of gases with smaller molecular size was negligible. The increase in the selectivities of the PSF by ozone treatment would be due to decrease in the free volume of the polymer because of the oxygen complexes generated by the reaction between ozone and the polymer.

• Journal of Sensor Science and Technology
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• v.23 no.6
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• pp.397-401
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• 2014

This paper describes the fabrication and characteristics of $C_2H_2$ gas sensor based on Ag-doped hierarchical ZnO nanostructures. In this work, a pure hierarchical ZnO structure was prepared using a simple hydrothermal method, and Ag nanoparticles doped the hierarchical ZnO structure were uniformly synthesized through photochemical route. The synthesized samples were characterized by SEM, TEM, EDS, XRD and PL spectra. Average size of prepared ZnO structures was around $2{\sim}3{\mu}m$ and showed highly uniform. The average size of Ag nanoparticles was 70 nm. The gas sensing properties of as-prepared products were investigated using resistivity-type gas sensors. 5 at% Ag-doped ZnO based sensors exhibited good performances for $C_2H_2$ gas in comparison with the un-doped one. The sensor based on Ag-doped hierarchical ZnO structures had linear response property from 5~1000 ppm of $C_2H_2$ concentration at working temperature of $200^{\circ}C$. The response values with 100 ppm $C_2H_2$ at $200^{\circ}C$ were 10% and 75% for pure and 5 at% Ag-doped hierarchical ZnO nanostructures, respectively. Moreover, the device showed excellent selectivity towards to $C_2H_2$ gas at optimal working temperature of $200^{\circ}C$.

• Membrane Journal
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• v.26 no.6
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• pp.421-431
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• 2016

Novel membrane technologies that harness ordered nanostructures have recently received much attention because they allow for high permeability due to their reduced flow resistance while also maintaining high selectivity due to their isoporous characteristics. In particular, the opaline structure (made from the self-assembly of colloidal particles) and its inverted form (inverse-opal) have shown strong potential for membrane applications on account of several advantages in processing and the resulting membrane properties. These include controllability over the pore size and surface functional moieties, which enable a wide range of applications ranging from size-exclusive separation to catalytically-reactive membranes. Furthermore, when combined with multiscale architecturing strategies, inverse-opal-structured membranes can be designed to have specific pores or channel structures. These materials are anticipated to be utilized for next-generation, high-performance, and high-value-added functional membranes. In this review article, various types of inverse-opal-structured membranes are reviewed and their functionalization through hierarchical structuring will be comprehensively investigated and discussed.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.3
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• pp.65-71
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• 1999

The effects of mask materials and etching solutions on the dimensional accuracy of V-groove were studied for the alignment between optoelectronic devices and optical fibers in optical packaging. PECVD nitride, LPCVD nitride, or thermal oxide($SiO_2$) was used as a mask material. The anisotropic etching solution was KOH(40wt%) or the mixture of KOH and IPA. LPCVB nitride has the best etching selectivity and thermal oxide was etched most rapidly in KOH(40wt%) at $85^{\circ}C$ among the mask materials studied here. The V-groove size enlarged than the designed value. This phenomenon was due to the undercutting benearth the mask layer from the etching toward Si (111) plane. The etch rate of (111) plane wart 0.034 - 0.037 $\mu\textrm{m}$/min in KOH(40wt%). This rate was almost same regardless of mask materials. When IPA added to KOH(40wt%), the etch rate of (100) plane and (111) plane decreased, but etching ratio of (100) to (111) plane increased. Consequently, the undercutting phenomenon due to etching toward (111) plane decreased and the size of V-groove could be controlled more accurately.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.4
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• pp.2277-2284
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• 2016

Ribosome-inactivating protein (RIP) from Mirabilis jalapa L. leaves has cytotoxic effects on breast cancer cell lines but is less toxic towards normal cells. However, it can easily be degraded after administration so it needs to be formulated into nanoparticles to increase its resistance to enzymatic degradation. The objectives of this study were to develop a protein extract of M. jalapa L. leaves (RIP-MJ) incorporated into nanoparticles conjugated with Anti-EpCAM antibodies, and to determine its cytotoxicity and selectivity in the T47D breast cancer cell line. RIP-MJ was extracted from red-flowered M. jalapa L. leaves. Nanoparticles were formulated based on polyelectrolyte complexation using low viscosity chitosan and alginate, then chemically conjugated with anti-EpCAM antibody using EDAC based on carbodiimide reaction. RIP-MJ nanoparticles were characterised for the particle size, polydispersity index, zeta potential, particle morphology, and entrapment efficiency. The cytotoxicity of RIP-MJ nanoparticles against T47D and Vero cells was then determined with MTT assay. The optimal formula of RIP-MJ nanoparticles was obtained at the concentration of RIP-MJ, low viscosity chitosan and alginate respectively 0.05%, 1%, and 0.4% (m/v). RIP-MJ nanoparticles are hexagonal with high entrapment efficiency of 98.6%, average size of 130.7 nm, polydispersity index of 0.380 and zeta potential +26.33 mV. The $IC_{50}$ values of both anti-EpCAM-conjugated and non-conjugated RIP-MJ nanoparticles for T47D cells (13.3 and $14.9{\mu}g/mL$) were lower than for Vero cells (27.8 and $33.6{\mu}g/mL$). The $IC_{50}$ values of conjugated and non-conjugated RIP-MJ for both cells were much lower than $IC_{50}$ values of non-formulated RIP-MJ (>$500{\mu}g/mL$).

• Journal of Sensor Science and Technology
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• v.24 no.1
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• pp.41-46
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• 2015

In this work, pure hierarchical ZnO structure was prepared using a simple hydrothermal method, and Ag nanoparticles doped hierarchical ZnO structure was synthesized uniformly through photochemical route. The reduced graphene oxide (rGO) has been synthesized by typical Hummer's method and reduced by hydrazine. Prepared Ag/ZnO nanostructures are uniformly dispersed on the surface of rGO sheets using ultrasonication process. The synthesized samples were characterized by SEM, TEM, EDS, XRD and PL spectra. The average size of prepared ZnO microspheres was around $2{\sim}3{\mu}m$ and showed highly uniform. The average size of doped-Ag nanoparticles was 50 nm and decorated into ZnO/rGO network. The $C_2H_2$ gas sensing properties of as-prepared products were investigated using resistivity-type gas sensor. Ag/ZnO-rGO based sensors exhibited good performances for $C_2H_2$ gas in comparison with the Ag/ZnO. The $C_2H_2$ sensor based on Ag/ZnO-rGO had linear response property from 3~1000 ppm of $C_2H_2$ concentration at working temperature of $200^{\circ}C$. The response values with 100 ppm $C_2H_2$ at $200^{\circ}C$ were 22% and 78% for Ag/ZnO and Ag/ZnO-rGO, respectively. In additions, the sensor still shows high sensitivity and quick response/recovery to $C_2H_2$ under high relative humidity conditions. Moreover, the device shows excellent selectivity towards to $C_2H_2$ gas at optimal working temperature of $200^{\circ}C$.

• Journal of Sensor Science and Technology
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• v.29 no.6
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• pp.388-393
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• 2020

In this study, a PbS quantum dots (QDs)-based H₂ gas sensor with a Pd electrode was proposed. QDs have a size of several nanometers, and they can exhibit a high surface area when forming a thin film. In particular, the NH₂ present in the ligand of PbS QDs and H₂ gas are combined to form NH₃⁺, subsequently the electrical characteristics of the QDs change. In addition to the resistance change owing to the reaction between Pd and H₂ gas, the resistance change owing to the reaction between the NH₂ of PbS QDs and H₂ gas increases the current signal at the sensor output, which can produce a high output signal for the same concentration of H₂ gas. Using the XRD and absorbance properties, the synthesis and particle size of the synthesized PbS QDs were analyzed. Using PbS QDs, the sensitivity was significantly improved by 44%. In addition, the proposed H₂ gas sensor has high selectivity because it has low reactivity with heterogeneous gases such as C₂H₂, CO₂, and CH₄.