25 results on '"Sung-Hwan Choi"'
Search Results
2. First breeding records of the osprey (Pandion haliaetus) on Jeju Island, South Korea
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Young-Hun Jeong, Sung-Hwan Choi, Maniram Banjade, Seon-Mi Park, Jun-Won Lee, and Hong-Shik Oh
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Ecology ,Insect Science ,Animal Science and Zoology ,Plant Science ,Ecology, Evolution, Behavior and Systematics - Published
- 2023
3. Multivalent network modifier upregulates bioactivity of multispecies biofilm-resistant polyalkenoate cement
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Jae-Sung Kwon, Woojin Choi, Kee Joon Lee, Taeho Kim, Jin-Man Kim, Utkarsh Mangal, Jinkee Hong, Do Hyun Kim, Sung Hwan Choi, Kwang Mahn Kim, Ji-Young Seo, Tae-Yun Kang, Ji Yeong Kim, Jung Yul Cha, and Joohee Lee
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chemistry.chemical_classification ,Secondary infection ,Biomedical Engineering ,Cationic polymerization ,Biofilm ,Apatite ,Divalent ,Biomaterials ,chemistry ,Downregulation and upregulation ,visual_art ,visual_art.visual_art_medium ,Biophysics ,Ion channel ,Ex vivo ,Biotechnology - Abstract
Polyalkenoate cement (PAC) is a promising material for regenerative hard tissue therapy. The ionically rich glass component of PAC encourages bioactive interaction via. the release of essential ions. However, PAC bioactivity is restricted owing to (i) structurally inherent cationic network formers and (ii) surface bacterial biofilm formation. These two factors cause a deficiency in ion release, further complicated by secondary infections and premature therapeutic failure. Here, a multivalent zwitterionic network modifier (mZM) is presented for upregulation of ionic exchange and bioactivity enhancement. By introducing a non-zero charged mZM into PACs, an increase in the proportion of non-bridging oxygen occurs. The network modification promotes ion channel formation, causing a multiple-fold increase in ion release and surface deposition of hydroxy-carbonate apatite (ca. 74%). Experiments ex vivo and animal models also demonstrate the efficient remineralization ability of the mZM. Furthermore, divalent cationic interaction results in bacterial biofilm reduction (ca. 68%) while also influencing a shift in the biofilm species composition, which favors commensal growth. Therefore, PAC modification with mZM offers a promising solution for upregulation of bioactivity, even aiding in customization by targeting site-specific regenerative therapy in future applications.
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- 2022
4. Cerium oxide nanozymes confer a cytoprotective and bio-friendly surface micro-environment to methacrylate based oro-facial prostheses
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Jie Jin, Utkarsh Mangal, Ji-Young Seo, Ji-Yeong Kim, Jeong-Hyun Ryu, Young-Hee Lee, Cerjay Lugtu, Geelsu Hwang, Jung-Yul Cha, Kee-Joon Lee, Hyung-Seog Yu, Kwang-Mahn Kim, Sungil Jang, Jae-Sung Kwon, and Sung-Hwan Choi
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Biomaterials ,Mechanics of Materials ,Biophysics ,Ceramics and Composites ,Bioengineering - Published
- 2023
5. Changes in mechanical and bacterial properties of denture base resin following nanoceria incorporation with and without SBA-15 carriers
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Utkarsh Mangal, Ji-Young Seo, Jeong-Hyun Ryu, Jie Jin, Chengzan Wu, Jung-Yul Cha, Kee-Joon Lee, Hyung-Seog Yu, Kwang-Mahn Kim, Jae-Sung Kwon, and Sung-Hwan Choi
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Biomaterials ,Mechanics of Materials ,Biomedical Engineering - Abstract
Poly (methyl methacrylate) (PMMA) is a commonly used material for the fabrication of biomedical appliances. Although PMMA has several advantages, it is susceptible to microbial insults with practical use. Therefore, different bioactive nanomaterials, such as nanoceria (CeN), have been proposed to enhance the properties of PMMA. In this study, we investigated the effect of the incorporation of CeN into PMMA with and without the use of mesoporous silica nanoparticle (SBA-15) carriers. The unmodified PMMA specimens (control, CTRL) were compared to groups containing SBA-15, CeN, and the synthesized SBA-15 impregnated with CeN (SBA-15@CeN) at different loading percentages. The mechanical and physical properties of the different SBA-15@CeN groups and their effects on cell viability were investigated, and the optimal CeN concentration was identified accordingly. Our results revealed that flexural strength was significantly (P 0.01) reduced in the SBA-15@CeN
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- 2023
6. Incorporation of carboxybetaine methacrylate into poly(methyl methacrylate) to prevent multi-species biofilm formation
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Jaehun Yu, Sung Hwan Choi, Jinkee Hong, Jae-Sung Kwon, Ji Yeong Kim, Woojin Choi, Ji-Young Seo, Myung-Jin Lee, and Jie Jin
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General Chemical Engineering ,macromolecular substances ,02 engineering and technology ,010402 general chemistry ,Methacrylate ,01 natural sciences ,Veillonella parvula ,chemistry.chemical_compound ,Methyl methacrylate ,biology ,Chemistry ,technology, industry, and agriculture ,Biofilm ,Adhesion ,equipment and supplies ,021001 nanoscience & nanotechnology ,biology.organism_classification ,Poly(methyl methacrylate) ,Multi-species biofilm formation ,0104 chemical sciences ,body regions ,Chemical engineering ,visual_art ,visual_art.visual_art_medium ,Actinomyces naeslundii ,0210 nano-technology - Abstract
Carboxybetaine methacrylate (CBMA), which has anti-biofouling properties, was incorporated into poly(methyl methacrylate) (PMMA) to prevent multi-species biofilm formation without impairing the critical mechanical properties of the PMMA. The incorporation of 2-methacryloyloxyethyl phosphorylcholine (MPC, 3 wt%) was used as a positive control. PMMA wettability was found to increase with increasing CBMA content. The addition of CBMA resulted in decreased mechanical properties of PMMA. The incorporation of 3% CBMA into PMMA resulted in considerable long-term anti-biofouling effects that reduce adhesion of various fungi, bacteria (Candida albicans, Actinomyces naeslundii, and Veillonella parvula), and a human saliva-derived biofilm. The anti-biofouling effect of CBMA-incorporated PMMA surpassed that of the positive control. By calculating the intensity of the collective band using Raman spectroscopy, CBMA was proven to form the most stable hydration layer. Neither CBMA nor MPC groups showed cytotoxicity. Occlusal splints fabricated using 3% CBMA showed clinically acceptable aesthetic properties with slight turbidity. Despite a limitation in terms of deteriorations of the mechanical properties, the addition of an appropriate amount of CBMA to PMMA inhibited the attachment of fungi and bacteria and suppressed multi-species biofilm growth. The aesthetic properties of CBMA-incorporated PMMA are acceptable for clinical practice.
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- 2020
7. Comparison of the Performance of Partial Least Squares and Support Vector Regressions for Predicting Fatty Acids and Fatty Acid Classes in Marine Oil Dietary Supplements by Using Vibrational Spectroscopic Data
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Sanjeewa R. Karunathilaka, Magdi M. Mossoba, Sung Hwan Choi, Lea Brückner, and Betsy Jean Yakes
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Mean squared error ,01 natural sciences ,Microbiology ,symbols.namesake ,0404 agricultural biotechnology ,Food Labeling ,Spectroscopy, Fourier Transform Infrared ,Partial least squares regression ,Least-Squares Analysis ,Fourier transform infrared spectroscopy ,Mathematics ,chemistry.chemical_classification ,Spectroscopy, Near-Infrared ,Chromatography ,Fatty Acids ,010401 analytical chemistry ,Fatty acid ,04 agricultural and veterinary sciences ,040401 food science ,Eicosapentaenoic acid ,0104 chemical sciences ,Support vector machine ,Fourier transform ,chemistry ,Docosahexaenoic acid ,Dietary Supplements ,symbols ,Food Science - Abstract
Simple, fast, and accurate analytical techniques for verifying the accuracy of label declarations for marine oil dietary supplements containing eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are required because of the increased consumption of these products. We recently developed broad-based partial least squares regression (PLS-R) models to quantify six fatty acids (FAs) and FA classes by using the spectroscopic data from a portable Fourier transform infrared (FTIR) device and a benchtop Fourier transform near infrared (FT-NIR) spectrometer. We developed an improved quantification method for these FAs and FA classes by incorporating a nonlinear calibration approach based on the machine learning technique support vector machines. For the two spectroscopic methods, high accuracy in prediction was indicated by low root mean square error of prediction and by correlation coefficients (R2) close to 1, indicating excellent model performance. The percent accuracy of the support vector regression (SV-R) model predicted values for EPA and DHA in the reference material was 90 to 110%. In comparison to PLS-R, SV-R accuracy for prediction of FA and FA class concentrations was up to 2.4 times higher for both ATR-FTIR and FT-NIR spectroscopic data. The SV-R models also provided closer agreement with the certified and reference values for the prediction of EPA and DHA in the reference standard. Based on our findings, the SV-R methods had superior accuracy and predictive quality for predicting the FA concentrations in marine oil dietary supplements. The combination of SV-R with ATR-FTIR and/or FT-NIR spectroscopic data can potentially be applied for the rapid screening of marine oil products to verify the accuracy of label declarations. HIGHLIGHTS
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- 2020
8. Organosilicate compound filler to increase the mechanical strength of superhydrophilic layer-by-layer assembled film
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Jae-Sung Kwon, Sohyeon Park, Sungwon Jung, Sung Hwan Choi, Jinkee Hong, Jiwoong Heo, and Woojin Choi
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Filler (packaging) ,Nanocomposite ,Materials science ,Biocompatibility ,General Chemical Engineering ,Layer by layer ,Composite number ,02 engineering and technology ,Substrate (electronics) ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Chitosan ,chemistry.chemical_compound ,chemistry ,Superhydrophilicity ,Composite material ,0210 nano-technology - Abstract
Technologies that can overcome the poor mechanical properties of the coatings with bacterial anti-adhesion effect based on super-wetting properties are still challenging. In this study, we developed a durable superhydrophilic nanocomposite coatings composed of polysaccharide matrix and organosilicate (OS) compound filler. In brief, carboxymethylcellulose (CMC) and chitosan (CS)-based multilayer films were fabricated via Layer-by-layer (LbL) assembly then crosslinking for the films was performed to improve inner stability and induce superhydrophilicity. As second step, we synthesized a biocompatible and robust organosilicate compound via sol-gel reaction and incorporate it as reinforcing filler into the superhydrophilic films. Consequently, durable hybrid superhydrophilic nanocomposites were coated on the substrate, and various chemical analysis and performance evaluations of the coatings were performed. The mechanical properties of the composite coatings were significantly improved due to the OS acting as a reinforcing filler in the multilayer films. Furthermore, the coatings exhibited excellent biocompatibility and transparency and exerted antibacterial effect based on superhydrophilic property. This study presents a practical strategy to solve the poor durability, the limitation of super-wetting coatings widely applied in various fields.
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- 2020
9. Bioactive resin-based composite with surface pre-reacted glass-ionomer filler and zwitterionic material to prevent the formation of multi-species biofilm
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Myung-Jin Lee, Sung-Il Jang, Kwang Mahn Kim, Jae-Sung Kwon, Jeong Hyun Ryu, Chung Ju Hwang, Ji-Young Seo, Sung Hwan Choi, and Ji Yeong Kim
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Materials science ,Glass ionomer cement ,02 engineering and technology ,Composite Resins ,Bacterial Adhesion ,Veillonella parvula ,Streptococcus mutans ,Dental Materials ,03 medical and health sciences ,0302 clinical medicine ,immune system diseases ,Humans ,General Materials Science ,General Dentistry ,biology ,Biofilm ,030206 dentistry ,Adhesion ,021001 nanoscience & nanotechnology ,biology.organism_classification ,Chemical engineering ,Mechanics of Materials ,Biofilms ,Actinomyces naeslundii ,Adsorption ,0210 nano-technology ,Antibacterial activity ,Protein adsorption - Abstract
This study evaluated the synergetic effect between surface pre-reacted glass-ionomer (SPRG) filler and 2-methacryloyloxyethyl phosphorylcholine (MPC), for inhibiting multi-species biofilm formation, while maintaining or even improving the original beneficial features of SPRG-filled resin-based composite (RBC).MPC (1.5-10wt%) was incorporated into commercial SPRG-filled RBC. Then, the inherent properties of RBC, and ion release and acid-neutralising properties associated with SPRG were investigated. Further, protein adsorptions and bacterial adhesion and viability on the SPRG-filled RBC surfaces were studied using four kinds of oral bacteria; Streptococcus mutans, Actinomyces naeslundii, Veillonella parvula, and Porphyromonas gingivalis. Finally, the thickness and biomass of the human saliva-derived biofilm model cultured on test and control samples were analysed.Addition of MPC content resulted in decreased flexural strength and wettability of SPRG-filled RBC. SPRG-filled RBC released significantly higher amounts of multiple ions as contents of MPC increased. Meanwhile, SPRG-filled RBC with 5-wt% MPC significantly improved acid-neutralising properties than those of other test and control samples (P0.001). SPRG-filled RBC with 3wt% MPC significantly reduced the amount of adsorbed bovine serum albumin and proteins from the brain heart infusion medium as compared to the control (P0.01). A similar trend was observed in the attachment of four types of bacteria and multi-species biofilm (P0.01).Despite limitation in terms of deteriorations of some physical properties, addition of 3% MPC to SPRG-filled RBC leads to inhibition of the attachment of multi-species bacteria on its surface, as well as inhibition of biofilm growth. Moreover, the original important bioactive features of SPRG-filled RBC such as ion release and acid neutralisations are either maintained or improved upon adding MPC.
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- 2019
10. Accuracy of 3-dimensional printed bracket transfer tray using an in-office indirect bonding system
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Seong-Hun Yoo, Sung-Hwan Choi, Kwang-Mahn Kim, Kee-Joon Lee, Young-Jun Kim, Jae-Hun Yu, Yeong-Il Choi, and Jung-Yul Cha
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Orthodontic Brackets ,Printing, Three-Dimensional ,Dental Bonding ,Computer-Aided Design ,Humans ,Orthodontics ,Models, Dental - Abstract
In this study, we aimed to evaluate and compare the bracket positioning accuracy of the indirect bonding (IDB) transfer tray fabricated in-clinic using the tray printing (TP) and marker-model printing methods (MP).The TP group was further divided into 2 groups (single-tray printing [STP] and multiple-tray printing [MTP]) depending on the presence of a tray split created using the 3-dimensional (3D) software. Five duplicated plaster models were used for each of the 3 experimental groups, and a total of 180 artificial teeth, except the second molar, were evaluated in the experiment. The dental model was scanned using a model scanner (E3; 3Shape Dental Systems, Copenhagen, Denmark). Virtual brackets were placed on facial axis points, and the IDB trays were designed and fabricated using a 3D printer (VIDA; EnvisionTEC, Mich). The accuracy of bracket positioning was evaluated by comparing the planned bracket positions and the actual bracket positions using 3D analysis on inspection software. The main effects and first-order interaction effects were analyzed together by analysis for the analysis of variance.The mean distance and height errors were significantly lower in the STP group than those in the MP and MTP groups (P 0.05). The mean distance error was 0.06 mm in the STP group and 0.09 mm in the MP and MTP groups. The mean height error was 0.10 mm in the STP group and 0.15 mm and 0.18 mm in MP and MTP groups, respectively. However, no significant differences were observed in the angular errors among the 3 groups.The in-office-fabricated IDB system with computer-aided design and 3D printer is clinically applicable after considering the linear and angular errors. We recommend IDB trays fabricated using the STP method owing to the lower frequency of bracket positioning errors and ease of fabrication.
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- 2022
11. Rapid classification and quantification of marine oil omega-3 supplements using ATR-FTIR, FT-NIR and chemometrics
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Sung Hwan Choi, Lea Brückner, Betsy Jean Yakes, Cynthia T. Srigley, Magdi M. Mossoba, Zachary Ellsworth, and Sanjeewa R. Karunathilaka
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chemistry.chemical_classification ,0303 health sciences ,Chromatography ,030309 nutrition & dietetics ,010401 analytical chemistry ,Fatty acid ,Linear discriminant analysis ,01 natural sciences ,Eicosapentaenoic acid ,0104 chemical sciences ,Chemometrics ,03 medical and health sciences ,chemistry ,Docosahexaenoic acid ,Partial least squares regression ,Fourier transform infrared spectroscopy ,Food Science ,Polyunsaturated fatty acid - Abstract
The increased demand for marine oil dietary supplements requires rapid and accurate screening to verify product quality and accuracy of label declarations. Simple and rapid procedures, based on spectra from a portable Fourier-transform infrared (FTIR) device and a benchtop FT-near infrared (FT-NIR) spectrometer combined with chemometrics, were developed to: (1) differentiate sources of omega-3 polyunsaturated fatty acids (PUFA) in their natural triacylglycerol (TAG) or concentrated ethyl ester (EE) forms, and (2) quantify six main fatty acids (FA)/FA classes. A partial least squares discriminant analysis (PLS-DA) model developed for ATR-FTIR data was successfully used to classify a large number of representative products (n = 95) as belonging to the TAG or EE classes, or as mixtures of such. Broad-based partial least squares regression (PLSR) models for each of six fatty acid (FA)/FA classes were successfully validated by cross-validation and by using an independent validation test set. For both complementary procedures, PLSR model predictions showed good linear correlations with a reference gas chromatographic method (R2 > 0.91) and excellent predictive qualities for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These simple, rapid, and nondestructive spectroscopic procedures have the potential for differentiating between natural and concentrated forms of omega-3 PUFA and verifying the accuracy of label declarations.
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- 2019
12. Long-Term Stability of Pre-Orthodontic Orthognathic Bimaxillary Surgery Using Intraoral Vertical Ramus Osteotomy Versus Conventional Surgery
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Kee-Deog Kim, Hyung Seog Yu, Chung Ju Hwang, Jeong Hwa Jeong, Sung Hwan Choi, and Sang-Hwy Lee
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Male ,medicine.medical_specialty ,Adolescent ,Cephalometry ,medicine.medical_treatment ,Osteotomy, Sagittal Split Ramus ,Conventional surgery ,Orthognathic surgery ,Osteotomy ,Orthodontics, Corrective ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Humans ,Osteotomy, Le Fort ,Maxillary Osteotomy ,Retrospective Studies ,Orthognathic Surgical Procedures ,business.industry ,Soft tissue ,Retrospective cohort study ,Vertical ramus osteotomy ,030206 dentistry ,Craniometry ,medicine.disease ,Surgery ,Malocclusion, Angle Class III ,Treatment Outcome ,Otorhinolaryngology ,030220 oncology & carcinogenesis ,Female ,Oral Surgery ,Malocclusion ,business - Abstract
Purpose The aim of the present study was to compare the long-term stability of bimaxillary surgery using an intraoral vertical ramus osteotomy (IVRO) with and without presurgical orthodontic treatment. Materials and Methods The present retrospective study included 31 consecutive patients with skeletal Class III malocclusions who had undergone bimaxillary surgery (Le Fort I osteotomy and bilateral IVRO). Patients were divided into 2 groups based on treatment type: pre-orthodontic orthognathic surgery (POGS; n = 17) and conventional surgery with presurgical orthodontic treatment (CS; n = 14). Lateral cephalograms were obtained before surgery, 1 day after surgery, 1 month after surgery, 1 year after surgery, and 2 years after surgery to evaluate skeletal and soft tissue changes between the 2 groups. Data were analyzed using χ2 tests, Mann-Whitney U tests, repeated-measures analyses of variance, and independent t tests. Results There was no significant difference in skeletal or soft tissue measurements—with the exception of the angle between the sella-and-nasion plane and the occlusal plane (SN-OP; P Conclusions These findings suggest that POGS and CS have similar long-term stability in patients with skeletal Class III malocclusion.
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- 2018
13. Tomographic similarity scan with a computed modified absolute mandibular midsagittal plane for precise and objective localization of mandibular asymmetry
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Kim Huisoo, Sung Hwan Choi, Han Arum, Utkarsh Mangal, Kee Joon Lee, Hyung Seog Yu, Jae Joon Hwang, and Yun Hoa Jung
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0301 basic medicine ,Orthodontics ,Cone beam computed tomography ,Mandible ,Health Informatics ,Cone-Beam Computed Tomography ,Volume Curve ,Sagittal plane ,Computer Science Applications ,Mental foramen ,03 medical and health sciences ,Imaging, Three-Dimensional ,030104 developmental biology ,0302 clinical medicine ,medicine.anatomical_structure ,stomatognathic system ,Similarity (network science) ,medicine ,Humans ,Superimposition ,Segmentation ,030217 neurology & neurosurgery ,Mathematics - Abstract
The application of 3D imaging is at its cusp in craniofacial diagnosis and treatment planning. However, most applications are limited to simple subjective superimposition-based analysis. As the diagnostic accuracy dictates the precision in operability, we propose a novel method that enables objective clinical decision making for patients with mandibular asymmetry. We analyzed cone-beam computed tomography (CBCT) scans of 34 patients who underwent surgical correction for mandibular asymmetry using a high-throughput computing algorithm. Radiomic segmentation of quantitative features of surface and volume followed by exploration resulted in identification of a computed modified absolute mandibular midsagittal plane (cmAMP). Tomographic similarity scan (ToSS) curves were generated via bilateral equidistant scanning in an antero-posterior direction with cmAMP as the reference. ToSS comprised of a comprehensive similarity index (SI) score curve and a segment-wise volume curve. The SI score was computed using the Sørensen-Dice similarity coefficient ranging from 0 to 1. The volumetric analysis was represented as the non-overlapping volume (NOV) and overlapping volume (OV) for each segment, with two segmentation lines, at the mental foramen anteriorly and the intraoral vertical ramus osteotomy region posteriorly. Statistical analysis showed strong negative correlation between the NOV and SI scores for the anterior, middle, and total mandible (P 0.001). Additionally, a significant correlation was observed between the change in the SI scores for anterior (P = 0.044) and middle segments (P 0.001) to the total mandible when comparing the data before and after the surgery. This work demonstrated the potential of incorporating ToSS curves in surgical simulation software to improve precision in the clinical decision-making process.
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- 2021
14. Is There a Difference in Stability After Intraoral Vertical Ramus Osteotomy Between Vertically High-Angle and Normal-Angle Patients?
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Chung Ju Hwang, Hyoung Seon Baik, Jung Yul Cha, Da Young Kang, Sung Hwan Choi, and Young-Soo Jung
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Adult ,Male ,Adolescent ,Cephalometry ,medicine.medical_treatment ,Osteotomy, Sagittal Split Ramus ,Dentistry ,Mandible ,Overbite ,Osteotomy ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Recurrence ,medicine ,Humans ,Aged ,Retrospective Studies ,Aged, 80 and over ,Orthodontics ,business.industry ,Vertical Dimension ,Retrospective cohort study ,030206 dentistry ,Middle Aged ,Craniometry ,medicine.disease ,Malocclusion, Angle Class III ,Treatment Outcome ,Otorhinolaryngology ,Sample size determination ,030220 oncology & carcinogenesis ,Maxilla ,Female ,Surgery ,Oral Surgery ,Malocclusion ,business ,Follow-Up Studies - Abstract
Purpose Few studies have evaluated the relapse pattern of intraoral vertical ramus osteotomy (IVRO) for the correction of mandibular prognathism with a high angle. The aim of this study was to measure the association between vertical facial types (high and normal mandibular plane angle) and relapse after IVRO for the management of mandibular prognathism. Materials and Methods The retrospective cohort study sample (skeletal Class III patients) was divided into 2 groups according to the angle of the sella-nasion plane relative to the mandibular plane (SN-MP) at the initial examination. Lateral cephalograms were analyzed for the predictor (facial type) and outcome (cephalometric changes over time) variables before surgery, 7 days after surgery, and 12 months after surgery. The 2 groups were matched for sample size (n = 20 in each). Data were analyzed using repeated-measures analysis of variance with Bonferroni correction. Results The normal-angle group (group N, SN-MP from 27° to 37°) and high-angle group (group H, SN-MP >37°) were not significantly different in terms of gender and age at the initial examination. Seven days after surgery, the mandibles in group H moved 2.5 mm more superiorly than those in group N (P = .013); consequently, the amount of overbite correction in group H was approximately 2 mm greater than that in group N (P = .002). Nevertheless, 12 months after surgery, there was no statistically significant difference in relapse of the maxilla and mandible between the 2 groups. In the 2 groups, the mandible moved approximately 0.7 mm superiorly during retention. Conclusions These findings suggest that IVRO is a clinically acceptable and stable treatment modality for mandibular prognathism with a high angle.
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- 2016
15. Retrospective study of maxillary sinus dimensions and pneumatization in adult patients with an anterior open bite
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Kee Joon Lee, Jung Yul Cha, Chung Ju Hwang, Jesung Ryu, and Sung Hwan Choi
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Adult ,Male ,0301 basic medicine ,Cone beam computed tomography ,Adolescent ,Maxillary sinus ,Dentistry ,Orthodontics ,Mandibular first molar ,Young Adult ,03 medical and health sciences ,Basal (phylogenetics) ,0302 clinical medicine ,Occlusion ,Alveolar Process ,Premolar ,medicine ,Humans ,Retrospective Studies ,Open bite ,business.industry ,Open Bite ,Retrospective cohort study ,030206 dentistry ,Cone-Beam Computed Tomography ,Maxillary Sinus ,medicine.anatomical_structure ,Case-Control Studies ,Female ,030101 anatomy & morphology ,business - Abstract
The aim of this study was to evaluate differences in the maxillary sinus floor levels between adults with an anterior open bite and those without.This retrospective study included 30 subjects: 15 adults with an anterior open bite (mean age, 21.5 ± 4.3 years) and 15 control subjects with normal occlusion (mean age, 21.7 ± 3.1 years). Cone-beam computed tomography and lateral cephalograms were analyzed before treatment.The open-bite group exhibited a significantly greater maxillary posterior alveolar height (P 0.05). The craniocaudal heights of the maxillary sinus in the region between the first and second molars and between the second premolar and first molar were significantly greater in the open bite group (40.5 and 39.0 mm, respectively) than in the control group (36.7 and 34.7 mm, respectively; P 0.05 for both). The basal bone heights in the regions between the first and second molars, the second premolar and first molar, and the first and second premolars were significantly smaller in the open-bite group than in the control group (P 0.001 for all).Vertical pneumatization of the maxillary sinus floor in the region between the first and second molars and between the second premolar and first molar is greater in adults with an anterior open bite than in those without, whereas basal bone height in the maxillary posterior region is lower in the open-bite patients.
- Published
- 2016
16. Stability of Pre-Orthodontic Orthognathic Surgery Using Intraoral Vertical Ramus Osteotomy Versus Conventional Treatment
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Chung Ju Hwang, Kee Joon Lee, Sung Hwan Choi, Young-Soo Jung, and Hyoung Seon Baik
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Adult ,Male ,Adolescent ,Tooth Movement Techniques ,Cephalometry ,medicine.medical_treatment ,Bone Screws ,Mandibular Osteotomy ,Orthognathic surgery ,Dentistry ,Mandible ,Osteotomy ,Cohort Studies ,Young Adult ,03 medical and health sciences ,Orthognathic Surgical Procedures ,0302 clinical medicine ,Absorbable Implants ,Bone plate ,Maxilla ,medicine ,Humans ,Osteotomy, Le Fort ,Prognathism ,Retrospective Studies ,Orthodontics ,business.industry ,Vertical Dimension ,030206 dentistry ,Craniometry ,medicine.disease ,Jaw Fixation Techniques ,Malocclusion, Angle Class III ,Treatment Outcome ,Otorhinolaryngology ,030220 oncology & carcinogenesis ,Female ,Surgery ,Oral Surgery ,Malocclusion ,business ,Bone Plates ,Follow-Up Studies - Abstract
Postoperative skeletal and dental changes were evaluated in patients with mandibular prognathism who underwent mandibular setback surgery using an intraoral vertical ramus osteotomy (IVRO) with and without presurgical orthodontic treatment.This retrospective cohort study included consecutive patients with skeletal Class III malocclusions who underwent IVRO. Patients treated with pre-orthodontic orthognathic surgery (POGS) were compared with patients treated with conventional surgery (CS) with presurgical orthodontics (control) using lateral cephalograms (taken preoperatively, 7 days postoperatively, and 12 months postoperatively). Predictor (group and timing), outcome (cephalometric measurements over time), and other (ie, baseline characteristics) variables were evaluated to determine the differences in postoperative horizontal and vertical positional changes of the mandible, such as point B. Baseline demographics were similar between the groups (N = 37; CS group, n = 17; POGS group, n = 20). The data were analyzed with an independent t test, the Mann-Whitney U test, the Fisher exact t test, Pearson correlation analysis, and simple linear regression analysis.The mean setback of the mandible at point B was similar, but the mandible of the POGS group, particularly the distal segment, moved superiorly during the postoperative period in conjunction with the removal of premature occlusal contacts (P.001). In the CS group, the mandible had significantly more backward movement 12 months after surgery compared with the POGS group (P.01). In the POGS group, horizontal and vertical postsurgical changes were linearly correlated with the amount of setback and vertical movement of the mandible.Mandibular setback surgery using IVRO without presurgical orthodontics leads to considerably different postoperative skeletal and dental changes compared with conventional treatment, with more superior movement being observed at point B during the 1-year postoperative period.
- Published
- 2016
17. Evaluation of the surface characteristics of anodic oxidized miniscrews and their impact on biomechanical stability: An experimental study in beagle dogs
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Jung Yul Cha, Sung Ho Jang, Sung Hwan Choi, and Chung Ju Hwang
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Male ,Materials science ,Surface Properties ,Scanning electron microscope ,Bone Screws ,chemistry.chemical_element ,Dentistry ,Orthodontics ,Mandible ,02 engineering and technology ,Surface finish ,Microscopy, Atomic Force ,Beagle ,Random Allocation ,03 medical and health sciences ,Dogs ,0302 clinical medicine ,Nickel ,Bone-Implant Interface ,Materials Testing ,Microscopy ,Alloys ,Orthodontic Anchorage Procedures ,Orthodontic Wires ,Surface roughness ,Animals ,Orthodontic Appliance Design ,Titanium ,Miniaturization ,business.industry ,Electrochemical Techniques ,Organ Size ,030206 dentistry ,021001 nanoscience & nanotechnology ,Biomechanical Phenomena ,Anode ,Machined surface ,Torque ,chemistry ,Microscopy, Electron, Scanning ,Stress, Mechanical ,0210 nano-technology ,business ,Oxidation-Reduction ,Dental Alloys ,Biomedical engineering - Abstract
In this study, we aimed to assess the surface characteristics and the biomechanical stability of miniscrews with an anodic oxidized surface compared with machined surface miniscrews in beagle dogs.Self-drilled, titanium-aluminum-vanadium alloy miniscrews with an anodic oxidized surface (n = 48) or a machined surface (n = 48) were placed into the mandibles of 12 beagle dogs. The surface characteristics of both types of miniscrews were analyzed before implantation with scanning electron microscopy and atomic force microscopy. Insertion torque was measured during placement of all 96 miniscrews. Half of the implants in each group (24 specimens per subgroup) received 200 to 250 g of tensile force for 3-week or 12-week loading periods. Removal torque was measured in 12 specimens of each subgroup, and bone-implant contact and bone volume were quantified in the other 12 specimens of each subgroup.Atomic force microscopy measurements demonstrated that the anodic oxidized surface miniscrews had significantly higher roughness parameters than did the machined surface miniscrews (P 0.001). The 2 types of miniscrews were not significantly different in insertion and removal torque values or in bone-implant contacts and bone volumes, regardless of the loading period.Anodic oxidized miniscrews have different surface roughness profiles but no clinically significant superiority in biomechanical stability compared with machined surface miniscrews.
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- 2016
18. Effect of Audiovisual Treatment Information on Relieving Anxiety in Patients Undergoing Impacted Mandibular Third Molar Removal
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Chung Ju Hwang, Jung Yul Cha, Ji Hoon Won, and Sung Hwan Choi
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Adult ,Male ,Dentistry ,Mandible ,Anxiety ,Trismus ,Audiovisual Aids ,law.invention ,Young Adult ,Randomized controlled trial ,law ,Informed consent ,medicine ,Humans ,Local anesthesia ,Prospective Studies ,Young adult ,Prospective cohort study ,business.industry ,Tooth, Impacted ,Otorhinolaryngology ,Tooth Extraction ,Female ,Surgery ,Oral Surgery ,medicine.symptom ,business - Abstract
The authors hypothesized that an audiovisual slide presentation that provided treatment information regarding the removal of an impacted mandibular third molar could improve patient knowledge of postoperative complications and decrease anxiety in young adults before and after surgery. A group that received an audiovisual description was compared with a group that received the conventional written description of the procedure.This randomized clinical trial included young adult patients who required surgical removal of an impacted mandibular third molar and fulfilled the predetermined criteria. The predictor variable was the presentation of an audiovisual slideshow. The audiovisual informed group provided informed consent after viewing an audiovisual slideshow. The control group provided informed consent after reading a written description of the procedure. The outcome variables were the State-Trait Anxiety Inventory, the Dental Anxiety Scale, a self-reported anxiety questionnaire, completed immediately before and 1 week after surgery, and a postoperative questionnaire about the level of understanding of potential postoperative complications. The data were analyzed with χ(2) tests, independent t tests, Mann-Whitney U tests, and Spearman rank correlation coefficients.Fifty-one patients fulfilled the inclusion criteria. The audiovisual informed group was comprised of 20 men and 5 women; the written informed group was comprised of 21 men and 5 women. The audiovisual informed group remembered significantly more information than the control group about a potential allergic reaction to local anesthesia or medication and potential trismus (P.05). The audiovisual informed group had lower self-reported anxiety scores than the control group 1 week after surgery (P .05).These results suggested that informing patients of the treatment with an audiovisual slide presentation could improve patient knowledge about postoperative complications and aid in alleviating anxiety after the surgical removal of an impacted mandibular third molar.
- Published
- 2015
19. Ladder-like polysilsesquioxanes with antibacterial chains and durable siloxane networks
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Jinkee Hong, Sung Hwan Choi, Daheui Choi, Myung-Jin Lee, Sungwon Jung, Sohyeon Park, Jae-Sung Kwon, Jiwoong Heo, Woojin Choi, and Ji Yeong Kim
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chemistry.chemical_classification ,Materials science ,General Chemical Engineering ,Quaternary ammonium cation ,02 engineering and technology ,General Chemistry ,Adhesion ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,chemistry.chemical_compound ,Membrane ,Chemical engineering ,chemistry ,Coating ,Siloxane ,Nano ,engineering ,Environmental Chemistry ,0210 nano-technology ,Hybrid material ,Alkyl - Abstract
Significant progress has been made in endowing biomedical materials with antibacterial properties. However, the commercialization of these systems still poses various practical challenges. In this study, we report a facile technique for the preparation of practical and efficient antibacterial coatings based on well-defined polysilsesquioxane (PSQ) structures containing quaternary ammonium cation and long alkyl chains. PSQ is a hybrid material containing organic groups within a flexible and robust siloxane network, and can be endowed with different functions according to the synthetic conditions employed in the sol-gel process. However, depending on the synthetic precursors, a non-uniform PSQ structure can be formed, which limits the functions and stability of the resulting material. Accordingly, we synthesized PSQs with homogeneously distributed quaternary ammonium cation and long alkyl chains, using optimized synthetic conditions. The PSQs were coated on devices via self-assembly, and the thickness of the coating could be controlled from the nano- to the microscale depending on the deposition time. All coated substrates exhibited more than 60% bacterial reduction rate for three types of bacteria compared to the control groups. The coating inhibited the activity of the membrane adhesins, which prevented the strong adhesion of bacteria to the surfaces. Furthermore, the coated substrates also showed an increased mechanical strength in bulk strength tests. The nanoscale coatings notably increased the hardness of the dental substrates more than twofold compared to that of the control. The easy preparation and efficacy of the PSQs highlight their applicability as antibacterial coatings in various medical devices requiring high durability.
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- 2020
20. Environmental and economic loss analyses of the oil discharge from shipwreck for salvage planning
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Jung-Yeul Jung, Ki-Cheol Park, Sung-Hwan Choi, and Moonjin Lee
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0106 biological sciences ,Pollution ,business.industry ,Oceans and Seas ,010604 marine biology & hydrobiology ,media_common.quotation_subject ,Wind ,010501 environmental sciences ,Aquatic Science ,Oceanography ,01 natural sciences ,Marine pollution ,Flood tide ,Aquaculture ,Environmental protection ,Open sea ,Oil spill ,Environmental science ,Petroleum Pollution ,Environmental Pollution ,business ,Environmental Monitoring ,0105 earth and related environmental sciences ,media_common - Abstract
In this study, we carry out environmental and economic loss analyses of the oil discharge from the shipwreck Jeh Hun. By performing 500 simulations of hypothetical oil spill cases, we obtain the minimum and worst damage cases. In the minimum damage case, there is just marine pollution without coastal pollution or aquaculture farm pollution. On the other hand, in the worst damage case, there is serious marine pollution, coastal pollution, and aquaculture pollution. The main purpose of the environmental and economic loss analyses is to support salvage planning for the shipwreck, because we have to consider the oil discharge from the shipwreck during oil removal and salvage. The results of this study show that the best salvage time is early morning in winter, when the northwest wind and maximum flood tide are dominant resulting in the spilt oil going forward into the open sea without coastal pollution and aquaculture pollution.
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- 2020
21. Impact of malocclusion and common oral diseases on oral health–related quality of life in young adults
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Baek Il Kim, Sung Hwan Choi, Jung Yul Cha, and Chung Ju Hwang
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Adult ,Male ,Index of Orthodontic Treatment Need ,Activities of daily living ,Adolescent ,Cross-sectional study ,Pain ,Dentistry ,Oral Health ,Orthodontics ,Physical examination ,Social Skills ,Young Adult ,Quality of life ,Activities of Daily Living ,Humans ,Medicine ,Young adult ,medicine.diagnostic_test ,DMF Index ,business.industry ,Odds ratio ,Temporomandibular Joint Disorders ,medicine.disease ,Confidence interval ,stomatognathic diseases ,Cross-Sectional Studies ,Quality of Life ,Educational Status ,Female ,Periodontal Index ,Malocclusion ,Mouth Diseases ,business ,Stress, Psychological - Abstract
The aim of this study was to assess the association between malocclusion and oral health-related quality of life in young adults without orthodontic treatment, controlling for sociodemographic factors and common oral diseases.The sample consisted of 429 Korean patients (328 men, 101 women) 18 to 32 years of age. They completed the Korean version of the oral health impact profile-14 questionnaire and had a clinical examination, including an assessment with the index of orthodontic treatment need-dental health component. We collected sociodemographic information (age, sex, and education level) and evaluated other common oral diseases (decayed, missing, and filled teeth; periodontal health status; temporomandibular disorder; and oral soft tissue diseases).Multiple logistic regression analysis showed that patients requiring extensive orthodontic treatment were more than 2.7 times as likely to have poor oral health-related quality of life as the corresponding "no treatment needed" reference group (odds ratio, 2.74; 95% confidence interval, 1.60-4.59; P0.001). Severe malocclusion is significantly associated with functional limitations, physical pain, and social disability in young adults.Malocclusion is a key factor associated with poor quality of life caused by limited oral function, pain, and social disability in young adults.
- Published
- 2015
22. Effect of gadolinium incorporation on optical characteristics of YNbO4:Eu3+ phosphors for lamp applications
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Gopinathan Anoop, Sung Hwan Choi, Kyung Pil Kim, D Suh, Hyunju Lee, and Jae Soo Yoo
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Gadolinium ,Analytical chemistry ,chemistry.chemical_element ,Phosphor ,General Chemistry ,Fluorescence ,Ion ,law.invention ,chemistry ,Geochemistry and Petrology ,Absorption band ,law ,Cold cathode ,Particle size ,Chromaticity - Abstract
Eu3+-doped (Y,Gd)NbO4 phosphor was synthesized by solid-state reaction for possible application in cold cathode fluorescent lamps.A broad absorption band with peak maximum at 272 nm was observed which was due to the charge transfer between Eu3+ ions and neighboring oxygen anions.A deep red emission at the peak wavelength of 612 nm was observed which could be attributed to the 5D0→7F2 transition in Eu3+ ions.The highest luminance for Y1x-yGdyNbO4:Eux3+ under 254 nm excitation was achieved at Eu3+ concentration of 18 mol.%(x=0.18) and Gd3+ concentration of 8.2 mol.% (v=0.082).The luminance of Y0.738Gd0.082NbO4:Eu3+0.18 was higher than that of a typical commercial phosphor Y2O3:Eu3+ and the CIE chromaticity coordinate was (0.6490,0.3506),which was deeper than that of Y2O3:Eu3+.The particle size of the synthesized phosphors was controlled by the NaCl flux and particle size as high as 8μm with uniform size distribution of particles was obtained.
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- 2012
23. High Temperature Tensile Deformation Behavior of New Heat Resistant Aluminum Alloy
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Bum-Suck Han, Kee-Ahn Lee, Si-Young Sung, Sung-Hwan Choi, Young-Ho Sohn, and Hyun-Joo Choi
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6111 aluminium alloy ,Materials science ,High temperature tensile ,Alloy ,chemistry.chemical_element ,Superplasticity ,Fractography ,5005 aluminium alloy ,engineering.material ,Aluminium ,Ultimate tensile strength ,Aluminium alloy ,Deformation behavior ,General Materials Science ,Engineering(all) ,Mechanical Engineering ,Heat-resistant aluminum alloy ,Strengthening phase ,Metallurgy ,General Medicine ,Condensed Matter Physics ,Microstructure ,chemistry ,Deformation mechanism ,Mechanics of Materials ,visual_art ,visual_art.visual_art_medium ,engineering ,6063 aluminium alloy ,Deformation (engineering) ,Co)3Al4 ,(Ni - Abstract
This study attempted to investigate the high temperature tensile deformation behaviour of new Al-1%Mg-1.1%Si0.8%CoNi heat resistant aluminium alloy. New aluminium alloy strengthened by Co-Ni based phase was manufactured by using powder ball milling and continuous casting, based on the alloy design & preliminary test. High temperature tensile tests were conducted at various temperatures from 25�� to 450�� . OM, SEM, EPMA, XRD, FIB and HR-TEM equipments were used to analyse microstructure, phases, and fracture surface. Microstructure of the new alloy mainly consisted of Al matrix and Co-Ni based phases (1~8 Πm). The Co-Ni based phase was analyzed and confirmed as (Ni, Co)3Al having incoherent interface with matrix. In high temperature tensile results, the new aluminium alloy didn’t show significant decrease (19.6%) of strength with increasing temperature (450�E ), suggesting totally different behaviour with conventional A319 alloy (87.0% decrease of T.S.). Fractography observation results of new alloy represented the ductile fracture mode with dimples. Voids were mainly initiated at Co-Ni based strengthening phases. It was apparently observed that the strengthening effect of the (Ni, Co)3Al could be still maintained at high temperature of 450�� . The deformation mechanism of this alloy was also discussed. © 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of ICM11
- Published
- 2011
- Full Text
- View/download PDF
24. High quality nanocrystalline silicon thin film fabricated by inductively coupled plasma chemical vapor deposition at 350°C
- Author
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Min-Koo Han, Sang-Myeon Han, Joong-Hyun Park, Sung-Hwan Choi, and Sun-Jae Kim
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Chemistry ,Ion plating ,Nanocrystalline silicon ,Analytical chemistry ,Sputter deposition ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Pulsed laser deposition ,Plasma-enhanced chemical vapor deposition ,Materials Chemistry ,Ceramics and Composites ,Thin film ,Layer (electronics) ,Plasma processing - Abstract
High quality nanocrystalline silicon (nc-Si) film was deposited by inductively coupled plasma chemical vapor deposition (ICP-CVD) without substrate RF bias at 350 °C. The nc-Si with a dense crystalline structure of the columnar type grew from the bottom to the top of the nc-Si film. A troublesome incubation layer did not exist at the bottom of the fabricated nc-Si film. A grain size of 40 nm was measured by using a SEM image. When a RF bias of 100 and 200 W was applied to the substrate to induce ion bombardment on the substrate, the crystalline structure and grains were not observed and a-Si deposition became dominant. The transition from nc-Si deposition into a-Si deposition can be attributed to ion bombardment which prevents nucleation and crystal growth at the surface of deposition. This shows that the reduction of ion bombardment can be a key factor to fabricate high quality nc-Si film. By using ICP-CVD with no substrate RF bias, ion bombardment can be reduced, while the density of plasma is kept high, so that high quality nc-Si can be fabricated due to the enhancement of crystalline growth on the surface.
- Published
- 2008
25. Suppress polystyrene thin film dewetting by modifying substrate surface with aminopropyltriethoxysilane
- Author
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Bi-min Zhang Newby and Sung-Hwan Choi
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chemistry.chemical_classification ,Materials science ,Hydrogen bond ,Annealing (metallurgy) ,Surfaces and Interfaces ,Polymer ,Condensed Matter Physics ,Surfaces, Coatings and Films ,chemistry.chemical_compound ,Silanol ,chemistry ,Chemical engineering ,Siloxane ,Polymer chemistry ,Materials Chemistry ,Polystyrene ,Dewetting ,Thin film - Abstract
Aminofunctional organosilanes, such as 3-aminopropyltriethoxysilane (APTES), have been widely utilized as adhesion promoters, and have also been found to have the ability to prevent dewetting of polymer thin films from substrates. The APTES molecule contains an active terminal amino group that can hydrogen bond with the multiple hydroxylated head groups in itself and hydroxyl groups on a substrate, thus forming cyclic structures and a complex loose network at ambient conditions. Upon heating, the hydrogen bond can be broken, allowing more silanol groups to condense with each other and form siloxane linkages, hence tightening the three-dimensional network. When a polymer thin film is in contact with the APTES layer during the thermal process, the polymer chains can diffuse/penetrate into the APTES network while the network is being tightened by the additional crosslinking. The penetrated and subsequently anchored chains could help to stabilize the thin film on the substrate. This hypothesis was verified by dewetting studies of thin films of polystyrene (PS), having molecular weights above and below the entanglement molecular weight ( M e ), from APTES and control surfaces when the systems were subjected to various treatments. Dewetting suppression was observed for PS/APTES that was thermally treated at ∼80 °C or 120 °C prior to the annealing of the thin film at higher temperatures. Much stronger suppression was noticed for PS having a molecular weight higher than M e . When PS thin films were deposited onto a precured APTES network, no dewetting suppression was observed.
- Published
- 2006
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