• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.5
• /
• pp.1-6
• /
• 2019

Organic dye-doped silica nanoparticles are used as a promising nanomaterials for bio-labeling, bio-imaging and bio-sensing. Fluorescent silica nanoparticles(NPs) have been synthesized by the modified $St{\ddot{o}}ber$ method. In this study, dye-free fluorescent silica NPs of various sized were synthesized by Sol-Gel process as the modified $St{\ddot{o}}ber$ method. The functional material of APTES((3-aminopropyl)triethoxysilane) was added as an additive during the Sol-Gel process. The as-synthesized silica NPs were calcined at $400^{\circ}C$ for 2 hours. The surface morphology and particle size of the as-synthesized silica NPs were characterized by field-emission scanning electron microscopy. The fluorescent characteristics of the as-synthesized silica NPs was confirmed by UV lamp irradiation of 365 nm wavelength. The photoluminescence (PL) of the as-synthesized silica NPs with different size was analyzed by fluorometry. As the results, the as-synthesized silica NPs exhibits same blue fluorescent characteristics for different NPs size. Especially, as increased of the silica NPs size, the intensity of PL was decreased. The blue fluorescence of dye-free silica NPs was attributed to linkage of $NH_2$ groups of the APTES layer and oxygen-related defects in the silica matrix skeleton.

• Journal of Powder Materials
• /
• v.21 no.1
• /
• pp.21-27
• /
• 2014

In this study, diatomite based materials were investigated as a support filter for silica particle coating. The silica sol for coating was synthesized by a st$\ddot{o}$ber process. The diatomite support was dry-pressed at 10 MPa and sintered at $1200^{\circ}C$ for 1 hour. The coating sol was prepared as a mixture of EtOH and silica sol. The diatomite support was coated by a dip-coating process. Silica coated diatomite filter was sintered at $1000{\sim}1200^{\circ}C$ for 1 hour. The largest pore size was decreased with increasing concentration ratio of coating sol. The gas and water permeability of silica coated diatomite decreased with increasing of concentration ratio of the coating sol.

• Journal of Legislation Research
• /
• no.53
• /
• pp.337-374
• /
• 2017

Wer wegen eines Wahldelikts zu Geldstrafe von mehr als 1 Million Won verurteilt wird, verliert nach ${\S}$ 18 Abs. 1 Satz 3, ${\S}$ 19 Satz 1, ${\S}$ 266 des Koreanischen Wahlgesetzes $f{\ddot{u}}r$ die Dauer von $f{\ddot{u}}nf$ Jahren die $F{\ddot{a}}higkeit$, ${\ddot{o}}ffentliche$ ${\ddot{A}}mter$ zu bekleiden und Rechte aus ${\ddot{o}}ffentlichen$ Wahlen. Bei Verurteilung zu Freiheitsstrafe wegen eines Wahldelikts ${\ddot{A}}mter$ sich die Dauer des Verlusts der $Amtsf{\ddot{a}}higkeit$ und des aktiven bzw. passiven Walhrechts auf 10 Jahre. Dies erfolgt kraft Gesetzes. Das $hei{\ss}t$, dass die Entscheidung ${\ddot{u}}ber$ das Ob und die Dauer des Verlusts nicht im Ermessen des Gerichts steht. Allerdings sollte $diesbez{\ddot{u}}glich$ nicht verkannt werden, dass ein deratriger Entzug von $Amtsf{\ddot{a}}higkeit$, $W{\ddot{a}}hlbarkeit$ u.s.w., mit dem eine Straftat geahndet werden soll, selber von Natur aus eine Art Strafen darstellt. Der im ${\S}$ 41 des Koreanischen StGB geregelte Strafen-Katalog $enth{\ddot{a}}lt$ $n{\ddot{a}}mlich$ eine zeitlich begrenzte Aberkennung des oben genannten ${\ddot{o}}ffentliche$n Rechtsstatus als eine Art Ehrenstrafen. Nicht einleuchtend ist, warum das Wesen der Sanktion $gem{\ddot{a}}{\ss}$ ${\S}$ 18 Abs. 1 Satz 3, ${\S}$ 19 Satz 1, ${\S}$ 266 des Koreanischen Wahlgesetzes, die den gleichen Zweck und die gleiche Rechtsfolge wie die im ${\S}$ 41 des Koreanischen StGB geregelte Ehrenstrafe hat, nicht als Strafe aufgefasst werden sollte. Handelt es sich bei der oben genannten Sanktion um eine Art Ehrenstrafen, so stellt sich die Anforderung, sie je nach der Eigenart der begangenen Tat bzw. des $T{\ddot{a}}ters$ zu individualisieren. Das Gebot der Individualisierung der Strafen, welches $haupts{\ddot{a}}chlich$ vom materiellen Rechtsstaatsprinzip ableitbar ist, kann im Grunde nur verwirklicht werden, wenn das Gericht dazu befugt ist, unter $Ber{\ddot{u}}cksichtigung$ der konkreten $Umst{\ddot{a}}nde$ jedes Einzelfalls ${\ddot{u}}ber$ eine angemessene Strafe zu befinden. Somit ist der kraft Gesetzes eintretenden Verlust der $Amtsf{\ddot{a}}higkeit$ und der $W{\ddot{a}}hlbarkeit$ nur schwer mit dem Gebot der Individualisierung der Strafen vereinbar. Es $w{\ddot{a}}re$ deshalb $w{\ddot{u}}nschenswert$, wenn der Gesetzgeber eine Reform in Betracht ziehen $w{\ddot{u}}rde$, welche den Ersatz des kraft Gesetzes automatisch eintretenden Entzugs der $Amtsf{\ddot{a}}higkeit$ bzw. des Wahlrechts durch die gerichtliche fakultative Aberkennung von diesen Statusrechten beinhaltet.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.2
• /
• pp.539-544
• /
• 2013

$Ag@SiO_2@SiO_2$(FITC) nanocomposites were prepared by the simple polyol process and St$\ddot{o}$ber method. Fluorescence enhancement of fluorescein moiety (fluorescein isothiocyanate, FITC) was investigated in the presence of silver nanoparticles in $Ag@SiO_2@SiO_2$(FITC) system with varying thickness (X nm) of first silica shell. Maximum enhancement factor of 4.3 fold was achieved in $Ag@SiO_2@SiO_2$(FITC) structure with the first silica shell thickness of 8 nm and the average separation distance of 11 nm between the surface of silver nanoparticle and fluorescein moiety. The enhancement is believed to be originated from increased excitation rate of fluorescein moiety due to concentrated local electromagnetic field which was improved by interaction of light with silver nanoparticles.

• Nuclear Engineering and Technology
• /
• v.44 no.8
• /
• pp.971-976
• /
• 2012

Silica-coated Au with Ag, Co, Cu, and Ir bimetallic radioisotope nanoparticles were synthesized by neutron irradiation, after coating $SiO_2$ onto the bimetallic particles by the sol-gel St$\ddot{o}$ber process. Bimetallic nanoparticles were synthesized by irradiating aqueous bimetallic ions at room temperature. Their shell and core diameters were recorded by TEM to be 100 - 112 nm and 20 - 50 nm, respectively. The bimetallic radioisotope nanoparticles' gamma spectra showed that they each contained two gamma-emitting nuclides. The nanoparticles could be used as radiotracers in petrochemical and refinery processes that involve temperatures that would decompose conventional organic radioactive labels.

• Advances in nano research
• /
• v.1 no.3
• /
• pp.159-169
• /
• 2013

A preparation method for gadolinium compound (GdC) nanoparticles coated with silica ($GdC/SiO_2$) is proposed. GdC nanoparticles were prepared with a homogeneous precipitation method at $80^{\circ}C$ using $1.0{\times}10^{-3}$ M $Gd(NO_3)_3$, 0.5 M urea and $0-3.0{\times}10^{-4}$ M ethylenediarinnetetraacetic acid disodium salt dihydrate (ETDA) in water. As a result of preparation at various EDTA concentrations, GdC nanoparticles with a size as small as $40.5{\pm}6.2$ nm, which were colloidally stable, were prepared at an EDTA concentration of $2.0{\times}10^{-4}$ M. Silica-coating of the GdC nanoparticles was performed by a St$\ddot{o}$ber method at $35^{\circ}C$ using $1.0-10.0{\times}10^{-3}$ M tetraethylorthosilicate (TEOS), 11 M $H_2O$ and $1.5{\times}10^{-3}$ M NaOH in ethanol in the presence of $1.0{\times}10^{-3}$ M GdC nanoparticles. Performance of preparation at various TEOS concentrations resulted in production of $GdC/SiO_2$ particles with an average size of $106.1{\pm}11.2$ nm at a TEOS concentration of $5.0{\times}10^{-3}$ M. The gadolinium (Gd) concentration of $1.0{\times}10^{-3}$ M in the as-prepared $GdC/SiO_2$ particle colloid solution was increased up to a Gd concentration of 0.2 M by concentrating with centrifugation. The core-shell structure of $GdC/SiO_2$ particles was undamaged, and the colloid solution was still colloidally stable, even after the concentrating process. The concentrated $GdC/SiO_2$ colloid solution showed images of X-ray and magnetic resonance with contrast as high as commercial Gd complex contrast agents.

• Journal of the Korean Ceramic Society
• /
• v.54 no.1
• /
• pp.49-54
• /
• 2017

In this study, based on hydrolysis and condensation via $St{\ddot{o}}ber$ process of sol-gel method, synthesis of mono-dispersed silica nanoparticles was carried out with hydrophilic solvent. This operation was expected to be a more simplified process than that with organic solvent. Based on the sol-gel method, which involves simply controlling the particle size, the particle size of the synthesized silica specimens were ranged from 30 to 300 nm by controlling the composition of tetraethylorthosilicate (TEOS), DI water and ammonia solution, and by varying the stirring speeds while maintaining a fixed amount of ethanol. Increasing the content of DI water and decreasing the content of ammonia caused the particle size to decrease, while controlling the stirring speed at a high level of RPMs enabled a decrease of the particle size. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) were utilized to investigate the success factors for synthesizing process; Field emission scanning electron microscopy (FE-SEM) was used to study the effects of the size and morphology of the synthesized particles. To analyze the dispersion properties, zeta potential and particle size distribution (PSD) analyses were utilized.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.4
• /
• pp.20-25
• /
• 2020

As nanoscience and nanotechnology advance, techniques for selective pattern growth have attracted significant attention. Silica nanoparticles (NPs) are used as a promising nanomaterials for bio-labeling, bio-imaging, and bio-sensing. In this study, silica NPs were synthesized by a sol-gel process using a modified Stöber method. In addition, the selective pattern growth of silica NPs was achieved by the surface functionalization of the substrate using a micro-contact printing technique of a hydrophobic treatment. The particle size of the as-synthesized silica NPs and morphology of selective pattern growth of silica NPs were characterized by FE-SEM. The contact angle by surface functionalization of the substrate was investigated using a contact angle analyzer. As a result, silica NPs were not observed on the hydrophobic surface of the OTS solution treatment, which was coated by spin coating. In contrast, the silica NPs were well coated on the hydrophilic surface after the KOH solution treatment. FE-SEM confirmed the selective pattern growth of silica NPs on a hydrophilic surface, which was functionalized using the micro-contact printing technique. If the characteristics of the selective pattern growth of silica NPs can be applied to dye-doped silica NPs, they will find applications in the bio imaging, and bio sensing fields.

• Applied Chemistry for Engineering
• /
• v.30 no.1
• /
• pp.88-94
• /
• 2019

Triplet-triplet annihilation upconversion (TTA-UC) is a photochemical process wherein two or more low-energy photons are converted to a high-energy photon through a special energy transfer mechanism. Herein, we report a strategy to enhance the efficiency of TTA-UC through the light-scattering effect induced by silica microparticles (SM) embedded in polymeric thin films. By incorporating monodisperse uniform silica microparticles with a uniform size of 950 nm synthesized by $St{\ddot{o}}ber$-based seeded growth method into UC polymeric thin films, the UC intensity in the 430-570 nm range was enhanced by as much as 64% when irradiated by 635 nm laser. Analyzing the lifetime of PdTPBP phosphorescence revealed that the presence of SM in the UC layer does not affect triplet-triplet energy transfer (TTET) between sensitizers and acceptors, supporting the enhancement of TTA-UC originated from the light-scattering effect. On the other hand, the incorporation of SM in UC layer is shown to enhance the triplet-triplet annihilation (TTA) efficiency, which results in a 1.5-fold increase of the ${\Phi}_{UC}$, by scattering light source and thus increasing the number of excited photons to be utilized in TTA-UC process.