• Bulletin of the Korean Chemical Society
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• v.30 no.8
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• pp.1755-1759
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• 2009

Surface structure and molecular orientation of self-assembled monolayers (SAMs) formed by the spontaneous adsorption of tetrahydrothiophene (THT) and thiophene (TP) on Au(111) were investigated by means of scanning tunneling microscopy (STM) and carbon K-edge near edge X-ray absorption fine structure (NEXAFS) spectroscopy. STM imaging revealed that THT SAMs have a commensurate (3 ${\times}\;2\sqrt[]{3}$) structure containing structural defects in ordered domains, whereas TP SAMs are composed of randomly adsorbed domains and paired molecular row domains that can be described as an incommensurate packing structure. The NEXAFS spectroscopy study showed that the average tilt angle of the aliphatic THT ring and $\pi$-conjugated TP ring in the SAMs were calculated to be about $30^o\;and\;40^o$, respectively, from the surface normal. It was also observed that the $\pi$* transition peak in the NEXAFS spectrum of the TP SAMs is very weak, suggesting that a strong interaction between $\pi$-electrons and the Au surface arises during the self-assembly of TP molecules. In this study, we have clearly demonstrated that the surface structure and adsorption orientation of organic SAMs on Au(111) are strongly influenced by whether the cyclic ring is saturated or unsaturated.

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1253-1257
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• 2011

The surface structures, adsorption conditions, and thermal desorption behaviors of cyclopentanethiol (CPT) self-assembled monolayers (SAMs) on Au(111) were investigated by scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and thermal desorption spectroscopy (TDS). STM imaging revealed that although the adsorption of CPT on Au(111) at room temperature generates disordered SAMs, CPT molecules at $50^{\circ}C$ formed well-ordered SAMs with a $(2{\surd}3{\times}{\surd}5)R41^{\circ}$ packing structure. XPS measurements showed that CPT SAMs at room temperature were formed via chemical reactions between the sulfur atoms and gold surfaces. TDS measurements showed two dominant TD peaks for the decomposed fragments ($C_5H_9^+$, m/e = 69) generated via C-S bond cleavage and the parent molecular species ($C_5H_9SH^+$, m/e = 102) derived from a recombination of the chemisorbed thiolates and hydrogen atoms near 440 K. Interestingly, dimerization of sulfur atoms in n-alkanethiol SAMs usually occurs during thermal desorption and the same reaction did not happen for CPT SAMs, which may be due to the steric hindrance of cyclic rings of the CPT molecules. In this study, we demonstrated that the alicyclic ring of organic thiols strongly affected the surface structure and thermal desorption behavior of SAMs, thus providing a good method for controlling chemical and physical properties of organic thiol SAMs.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.6
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• pp.664-670
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• 2018

In modern society, CCTV, which is the eye of surveillance, is being used to collect image data in various ways in daily life. CCTV is used not only for security, surveillance, and crime prevention but also in many fields such as automobile and black box. In this paper, we have developed a STM32F407 ARM chip based camera system for various applications. In order to develop camera system, modeling of camera system based on 3D structure was carried out in SolidWorks environment. The PCB board design was developed to extract the PCB parts from the camera system modeling files into iges files, convert them from the Altium Designer tool into 3D and 2D boards, After designing the camera system circuit and PCB, we have been studying the implementation of the stable system by using TRM (Thermal Risk Management) tool to cope with the heat simulation generated on the board.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.3
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• pp.99-106
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• 1998

Recently, scientists introduced a new type of microscope capable of investigating nonconducting surfaces in an atomic scale, which is called AFM (Atomic Force Microscope). It was an innovative attempt to overcome the limitation of STM (Scanning Tunnelling Microscope) which has been able to obtain the image of conducting surfaces. Surfaces of samples are imaged with atomic resolution. The AFM is an imaging tool or a profiler with unprecedented 3-D resolution for various surface types. The AFM technology, however, leaves a lot of room for improvement due to its delicate and fragile probing mechanism. One of the room for improvements is gap control between probe tip and sample surface. Distance between probe tip and sample surface must be kept in below one Angtrom in order to measure the sample surface in Angstrom resolution. In this paper, AFM system modeling, experimental system identification and control scheme based on system identification are performed and finally sample surface is measured by home-built AFM with such a control scheme.

• Journal of Korean Library and Information Science Society
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• v.53 no.2
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• pp.333-353
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• 2022

This study analyzed the relevance of the curriculum by applying topic modeling to book reports written as content area reading activities in the 'physics' class. In order to carry out the research, 332 physics book reports were collected to analyze the relevance among keywords and topics were extracted using STM. The result of the analysis showed that the main keywords of the physics book reports were 'thought', 'content', 'explain', 'theory', 'person', 'understanding'. To examine the influence and connection relationship of the derived keywords, the study presented degree centrality, between centrality, and eigenvetor centrality. As a result of the topic modeling analysis, eleven topics related to the physics curriculum were extracted, and the curriculum linkage could be drawn in three subjects (Physics I, Physics II, Science History), and six areas (force and motion, modern physics, wave, heat and energy, Western science history, and What is science). The analyzed results can be used as evidence for a more systematic implementation of content area reading activities which reflect the subject characteristics in the future.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.1
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• pp.21-26
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• 2006

Considering the skeletal class III malocclusion that complains of mandibular prognathism, there have been some studies of the mandibular change for comparing the changes of pre operative with post operative state. Nowadays it is common to do the orthognathic 2-jaw surgery for the correction of the maxillary deficiency, the post operative stability and the esthetics. We compare and analyze the changes of soft tissue around the nose and the lip with the changes in the direction and the amount of maxilla. Patients who were diagnosed as maxillofacial deformity and received orthognathic surgery of both jaws at Yongdong Severance hospital from 2001 through 2003 were included in this study. Their lateral cephalograms were analyzed, and the post operative change of hard tissue and soft tissue were studied. Upon analyzing the preoperative cephalograms and 6 month post operative cephalograms, there were significant in the vertical change of Labialis superius(Ls) and Stomion(Stm) in soft tissue in relation to the vertical change of skeletal landmarks (Anterior Nasal Spine, Subspinale, Prosthion, Incision Superious). In addition, there were no significance in horizontal movement of the skeletal landmarks among groups. In terms of hard tissue landmarks, group 3(maxillary posterior impaction and advancement surgery group) showed significantly greater change in the vertical movement of Anterior Nasal Spine(ANS), Subspinale(A), Prosthion(Pr), and Incision Superious(Is) compared with other groups. In terms of soft tissue change, group 3 showed more significant change in the vertical movement of Ls and Stm. This study calculated the changes of the skeletal and soft tissue landmarks in order to act as a guide in planning and performing the surgery and as a reference in predicting the postoperative change of facial appearance.

• Spatial Information Research
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• v.11 no.4
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• pp.371-389
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• 2003

This study aims at defining the concept of a cyber-geospace and proposing how to establish a cyber-geospace fir the entire country in detail. The study defined the cyber-geospace as 'the dynamic second territory of Korea not only to manage the land systematicality and deal with administrative services for the people in aspect of public sector, but also to contain economic activities of corporations and the citizen's everyday lives in aspect of private sector, in a 3D virtual reality made by digitizing various facilities and buildings as well as the entire toterritory including ground, underground and even sea'. In order to establish such a cyber-geospace, the project should be pursued on the national level fir around ten-year period.

• The Journal of Advanced Prosthodontics
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• v.1 no.2
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• pp.68-74
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• 2009

STATEMENT OF PROBLEM. When veneering composite resin-metal restoration is prepared, the fact that bond strength between Ti and composite resin is relatively weak should be considered. PURPOSE. The purpose of this study is to evaluate the shear bond strength between the veneering composite resin and commercial pure (CP) Ti / Ti-6Al-4V alloy according to the method of surface treatment. MATERIAL AND METHODS. The disks were cast by two types of metal. Their surfaces were treated by sandblasting, metal conditioner, TiN coating and silicoating respectively. After surface treatment, the disks were veneered by composite resin (Tescera$^{TM}$, Bisco, USA) which is 5 mm in diameter and 3 mm in thickness. The specimens were stored in water at $25^{\circ}C$ for 24 hours, and then evaluated for their shear bond strength by universal testing machine (STM-$5^{(R)}$, United Calibration, USA). These values were statistically analyzed. RESULTS. 1. All methods of surface treatment were used in this study satisfied the requirements of ISO 10477 which is the standard of polymer-based crown and bridge materials. 2. The metal conditioner treated group showed the highest value in shear bond strength of CP Ti, silicoated group, TiN coated group, sandblasted group, in following order. 3. The silicoated group showed the highest value in shear bond strength of Ti-6Al-4V alloy, metal conditioner treated group, sandblasted group, TiN coated group, in following order. CONCLUSION. Within the limitations of this study, all methods of surface treatment used in this study are clinically available.

• Journal of Technologic Dentistry
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• v.39 no.3
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• pp.161-167
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• 2017

Purpose: We compare the bond strength of heat-cured PMMA of Lucitone 199 and QC-20 and Tokuyama Rebase Resin of self-cured resin, which are widely used and well accepted in clinical practice. In order to test the mechanical bonding and chemical bonding, we will compare the bond strength between EstheShot Bright, Smiletone, Repair and Rebase resins. Methods: The denture base resin used in this study was PMMA heat-cured QC-20 and Lucitone 199, polyamide resin EstheShot Bright, Smiletone. And Two types of self-curing Rapid Repair and Tokuyama Rebase were used as resection resins. To measure the bond strength, the denture specimens were fabricated in the size of $10{\times}64{\times}3.5mm$ as instructed by the manufacturer. A surface treatment agent was applied to the cut surfaces of each denture specimen, and the specimens were placed in a preformed silicone mold, and autoclaved excimer resins were prepared. The bending strength of the fabricated specimens was measured using a universal testing machine (STM-5, United Calibration Co., U.S.A.) to measure the three-point bending strength. Results: In both polycarbonate and polyacetal resin, a special resin surface treatment agent showed higher bonding strength than the resin surface treatment agent(p<0.05). Regardless of the type of surface treatment, polycarbonate showed higher bond strength than polyacetal resin(p<0.05). Conclusion: It is considered desirable to use a special surface treating agent for the thermoplastic denture base resin such as polycarbonate and polyacetal resin.

• Journal of Convergence for Information Technology
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• v.10 no.9
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• pp.200-205
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• 2020

This study investigates the effects of instrument-assisted soft mobilization (IASTM) and manual myofascial release (MFR) on the muscle activity of the biceps brachii. This study was conducted on 10 men and women in their 20s, and all subjects participated in the experiment for 3 days and measured muscle activity of the upper forearm muscles. On the first day, the muscle activity value was measured before the intervention, and the remaining two days were measured for muscle activity after the intervention of each manual therapy in a random order. All muscle activity values were compared and analyzed through the dependent t test and the independent t test. The before and after comparison of muscle activity values before and after each intervention was verified by performing the dependent t test and comparing the values of muscle activity between groups between each intervention after intervention by performing an independent t test. According to the results of this study, both interventions significantly increased muscle activity of the biceps brachii before and after intervention, and there was no significant difference in muscle activity values between groups after intervention. Therefore, both manual therapy (IASTM, MFR) are thought to be effective in improving neuromuscular control ability.