• Korean Journal of Radiology
• /
• v.25 no.9
• /
• pp.833-842
• /
• 2024

Objective: To assess the effect of a new lung enhancement filter combined with deep learning image reconstruction (DLIR) algorithm on image quality and ground-glass nodule (GGN) sharpness compared to hybrid iterative reconstruction or DLIR alone. Materials and Methods: Five artificial spherical GGNs with various densities (-250, -350, -450, -550, and -630 Hounsfield units) and 10 mm in diameter were placed in a thorax anthropomorphic phantom. Four scans at four different radiation dose levels were performed using a 256-slice CT (Revolution Apex CT, GE Healthcare). Each scan was reconstructed using three different reconstruction algorithms: adaptive statistical iterative reconstruction-V at a level of 50% (AR50), Truefidelity (TF), which is a DLIR method, and TF with a lung enhancement filter (TF + Lu). Thus, 12 sets of reconstructed images were obtained and analyzed. Image noise, signal-to-noise ratio, and contrast-to-noise ratio were compared among the three reconstruction algorithms. Nodule sharpness was compared among the three reconstruction algorithms using the full-width at half-maximum value. Furthermore, subjective image quality analysis was performed. Results: AR50 demonstrated the highest level of noise, which was decreased by using TF + Lu and TF alone (P = 0.001). TF + Lu significantly improved nodule sharpness at all radiation doses compared to TF alone (P = 0.001). The nodule sharpness of TF + Lu was similar to that of AR50. Using TF alone resulted in the lowest nodule sharpness. Conclusion: Adding a lung enhancement filter to DLIR (TF + Lu) significantly improved the nodule sharpness compared to DLIR alone (TF). TF + Lu can be an effective reconstruction technique to enhance image quality and GGN evaluation in ultralow-dose chest CT scans.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.22 no.2
• /
• pp.181-191
• /
• 2006

The objectives of this study were to evaluate the tensile strength of resin-infiltrated demineralized dentin according to the demineralization time, and to evaluate the tensile strength of hybrid layer that is formed by infiltrating different priming adhesives or primer/adhesive into demineralizd dentin matrix. Seventy five hour-glass shaped dentin specimens were prepared in mid-coronal dentin from extracted human molars. Thirty specimens were distributed into three groups according to demineralization time - 2 hours, 4 hours and 8 hours. Each specimen was placed in primer/adhesive of All-Bond 2 for 5 hours of infiltration. Another forty-five specimens of them were demineralized in 37% phosphoric acid for 4 hours. They were randomly assigned to three experimental groups - AB, SB and OS - to designate All-Bond 2, Single Bond and One-Step. Each specimen was placed in one of three different adhesives for 5 hours of infiltration. The specimens were visible light-cured for 5 minutes, and then stored for 24 hours in distilled water at $37^{\circ}C$. After that, microtensile bond strength for each specimen was measured, and the fractured surfaces were then observed by SEM. The data were statistically analysed by one-way ANOVA and Tukey's multiple comparison test and Bonferroni's multiple comparison test. The results were as follows; 1. Tensile strength of the group demineralized for 4 hours was significantly higher than that of groups demineralized for 2 hours and 8 hours (P < .01). 3. Tensile strength of the AB group was significantly higher than that of the SB group and OS group (P < .01).

• Applied Chemistry for Engineering
• /
• v.18 no.4
• /
• pp.386-390
• /
• 2007

In this study, polyurethane prepolymers were synthesized from polycaprolactonediol (PCDs. M.W. 530, 830, 1000, 1250, and 2000) and polycaprolactonetriol (PCTs. M.W. 300 and 900), and hexamethylenediisocyanate (HMDI). Polyurethane beads was prepared from the different prepolymers by a two-step suspension polymerization. The particle size of polyurethane beads was investigated by particle size analyzer. The beads were $10{\sim}30{\mu}m$ in size. The structure of beads was confirmed by FT-IR spectrometer. Their thermal properties were analyzed by TGA. Glass transition temperatures ($T_g$) of the beads were in the range of $-23{\sim}-53^{\circ}C$ and decreased with the increase of the PCD molecular weight. In order to prevention the cohesion of beads, the beads were coated with tetraethoxysilane (TEOS).

• Applied Chemistry for Engineering
• /
• v.25 no.4
• /
• pp.352-356
• /
• 2014

PDMS modified epoxy resin with epoxy group (EMPDMS) was prepared from the reaction of ${\alpha},{\omega}$-aminopropylpolydimethylsiloxane and diglycidyl ether of bisphenol-A (DGEBA) based epoxy resin, and PDMS modified epoxy hybrid compound (EMPDMSH) was prepared by introducing alkylesteraminopropyl alkoxy silane to EMPDMS. Their structures were characterized using FT-IR, $^1H$-NMR and $^{29}Si$-NMR. Coating materials were prepared by mixing EMPDMSH base and solvent. Physical properties of the coating materials coated on epoxy/glass fiber composite film were measured according to the content of PDMS in EMPDMSH. Contact angle of coating film was increased 30 to 71 degree. Adhesive property of coating film was 5B degree better then epoxy or acrylate coating materials, and surface roughness was decreased as increasing in EMPDMSH.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.396-396
• /
• 2013

The resistive random access memory (ReRAM) has several advantages to apply next generation non-volatile memory device, because of fast switching time, long retentions, and large memory windows. The high mobility of monolayered graphene showed several possibilities for scale down and electrical property enhancement of memory device. In this study, the monolayered graphene grown by chemical vapor deposition was transferred to $SiO_2$ (100 nm)/Si substrate and glass by using PMMA coating method. For formation of metal-oxide nanoparticles, we used a chemical reaction between metal films and polyamic acid layer. The 50-nm thick BPDA-PDA polyamic acid layer was coated on the graphene layer. Through soft baking at $125^{\circ}C$ or 30 min, solvent in polyimide layer was removed. Then, 5-nm-thick indium layer was deposited by using thermal evaporator at room temperature. And then, the second polyimide layer was coated on the indium thin film. After remove solvent and open bottom graphene layer, the samples were annealed at $400^{\circ}C$ or 1 hr by using furnace in $N_2$ ambient. The average diameter and density of nanoparticle were depending on annealing temperature and times. During annealing process, the metal and oxygen ions combined to create $In_2O_3$ nanoparticle in the polyimide layer. The electrical properties of $In_2O_3$ nanoparticle ReRAM such as current-voltage curve, operation speed and retention discussed for applictions of transparent and flexible hybrid ReRAM device.

• Elastomers and Composites
• /
• v.44 no.1
• /
• pp.34-40
• /
• 2009

New coupling agent or surface modified agent (9-decenoic acid) was used to enhance the compatibility between silica and polystyrene in silica/polystyrene hybrid nanocomposite, synthesized by in situ miniemulsion polymerization. Composites contain well dispersed nanosize silica particles. Related tests and analyses confirmed the success of synthesis. Functionalization of silica by 9-decenoic acid and silica on the polystyrene was confirmed by FTIR. TGA showed presence and amount of silica in final latex. The glass transition temperature of the hybrid nanocomposite was increased with the silica amount. SEM and TEM analysis showed the spherical morphology of PS and composite with an average diameter of 55 nm. The presence of silica within composite was confirmed by EDS attached to the existing TEM.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.11 no.4
• /
• pp.91-97
• /
• 2011

In this paper we present an approach to the structure identification based on genetic algorithm and to the parameter identification by hybrid learning method in neuro-fuzzy-genetic hybrid system in order to predicate the Mackey-Glass Chaotic time series. In this scheme the basic idea consists of two steps. One is the construction of a fuzzy rule base for the partitioned input space via genetic algorithm, the other is the corresponding parameters of the fuzzy control rules adapted by the backpropagation algorithm. In an attempt to test the performance the proposed system, three patterns, x(t-3), x(t-6) and x(t-9), was prepared according to time interval. It was through lots of simulation proved that the initial small error of learning owed to the good structural identification via genetic algorithm. The performance was showed in Table 2.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.11a
• /
• pp.396-399
• /
• 2003

In this paper, the purpose is to develop imaging technique of synchrotron radiation using CMOS image sensor. The detector using hybrid method to be research in this lab was used, in order to increase image signal. We made experiments with 1B2 Whitebeam/microprobe beamline in PAL (Pohang Accelerator Laboratory). Phosphor materials such as ZnS:(Ag,Li), ZnS:(Cu,Al), $Y_2O_2S:Eu$ were produced by spin coating on glass. Synchrotron radiation images were acquired and evaluated from monochromatic light from monochromoator in PAL 1B2line. From obtained object and phantom, MTF was 0.15 in ZnS:(Ag,Li) phosphor, and 0.178 in ZnS:( Cu,Al) at 151p/mm. MTFs were unsystematic because thickness of phosphor and uniformity of surface were not optimized. It's expected to improve MTF and the qualify of images as uniformity's optimized.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.97-97
• /
• 2010

We demonstrate the hybrid polymer-quantum dot based multi-functional device (Organic bistable devices, Light-emitting diode, and Photovoltaic cell) with a single active-layer structure consisting of CdSe/ZnS semiconductor quantum-dots (QDs) dispersed in a poly N-vinylcarbazole (PVK) and 1,3,5-tirs- (N-phenylbenzimidazol-2-yl) benzene (TPBi) fabricated on indium-tin-oxide (ITO)/glass substrate by using a simple spin coating technique. The multi-functionality of the device as Organic bistable device (OBD), Light Emitting Diode (LED), and Photovoltaic cell can be successfully achieved by adding an electron transport layer (ETL) TPBi to OBD for attaining the functions of LED and Photovoltaic cell in which the lowest unoccupied molecular orbital (LUMO) level of TPBi is positioned at the energy level between the conduction band of CdSe/ZnS and LiF/Al electrode (band-gap engineering). Through transmission electron microscopy (TEM) study, the active layer of the device has a p-i-n structure of a consolidated core-shell structure in which semiconductor QDs are uniformly and isotropically adsorbed on the surface of a p-type polymer core and the n-type small molecular organic materials surround the semiconductor QDs.

• The Journal of Advanced Prosthodontics
• /
• v.12 no.6
• /
• pp.344-350
• /
• 2020

PURPOSE. Recently introduced hybrid and reinforced glass ceramic computer-aided design/computer-aided manufacturing (CAD/CAM) materials have been used for full-coverage restorations. However; the effect of adjustment and type of materials on internal and marginal adaptation are unknown. This study aimed to evaluate and compare the marginal and internal adaptations of crowns made of three different CAD/CAM materials before and after adjustment. MATERIALS AND METHODS. One acrylic resin maxillary first molar was prepared and served as the master die. Thirty-six restorations were fabricated using CAD/CAM system (CEREC Omnicam, MCXL) with three materials including lithium disilicate (IPS e.max CAD), zirconia-reinforced lithium silicate (Suprinity), and hybrid ceramic (Enamic). Internal and marginal adaptations were evaluated with the reference point matching technique before and after adjustment. The data were analyzed using mixed ANOVA considering α=.05 as the significance level. RESULTS. The effect of adjustment and its interaction with the restoration material were significant for marginal, absolute marginal, and occlusal discrepancies (P<.05). Before adjustment, Suprinity had lower marginal discrepancies than IPS e.max CAD (P=.18) and Enamic (P=.021); though no significant differences existed after adjustment. CONCLUSION. Within the limitations of this study, crowns fabricated from IPS e.max CAD and Suprinity resulted in slightly better adaptation compared with Enamic crowns before adjustment. However, marginal, axial, and occlusal discrepancies were similar among all materials after the adjustment.