• Korean Journal of Materials Research
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• v.21 no.3
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• pp.168-173
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• 2011

Precipitation of the ordered icosahedral quasicrystal in Mg-6wt%Zn-1wt%Y alloy has been characterized by transmission electron microscopy observations. The lamellar-type icosahedral qusicrystal phases (I-phase) with the face-centered icosahedral (FCI) structure are observed in alloy after solution treatment at $550^{\circ}C$. In the alloy annealed at $400^{\circ}C$, polygon-shaped I-phases are observed in the ${\alpha}$-Mg matrix. The interfaces of the I-phase with the matrix are facetted and the facets are on five-fold and two- fold plane of the I-phase. The orientation relationship of the I-phase with the matrix is determined to be $[I5]_I//[001]_{Mg}$, $(2f)_I//(2\overline{1}0)_{Mg}$ and $[I2]_I//[311]_{Mg}$, $(5f)_I//(0\overline{1}1)_{Mg}$. The icosahedral grains are occasionally found to be twinned with one of the five-fold axis as the twin axis. The twin boundaries appear to be fairly straight and perpendicular to the fivefold twin axis. The icosahedral twin can be expressed as a rotation of $63.4^{\circ}$ or $116.62^{\circ}$ around two fold zone axis.

• Applied Microscopy
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• v.49
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• pp.1.1-1.10
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• 2019

Joints of three-dimensional (3D) rutile-type (r) tin dioxide ($SnO_2$) nanowire networks, produced by the flame transport synthesis (FTS), are formed by coherent twin boundaries at $(101)^r$ serving for the interpenetration of the nanowires. Transmission electron microscopy (TEM) methods, i.e. high resolution and (precession) electron diffraction (PED), were utilized to collect information of the atomic interface structure along the edge-on zone axes $[010]^r$, $[111]^r$ and superposition directions $[001]^r$, $[101]^r$. A model of the twin boundary is generated by a supercell approach, serving as base for simulations of all given real and reciprocal space data as for the elaboration of three-dimensional, i.e. relrod and higher order Laue zones (HOLZ), contributions to the intensity distribution of PED patterns. Confirmed by the comparison of simulated and experimental findings, details of the structural distortion at the twin boundary can be demonstrated.

• Journal of the korean academy of Pediatric Dentistry
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• v.21 no.2
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• pp.577-585
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• 1994

The Twin Blocks technique was developed by Dr. William Clark of Scotland during the early 1980's. Twin Blocks are an uncomplicated system that incorporates the use of upper and lower bite blocks. These blocks reposition the mandible and redirect occlusal forces to achieve rapid correction of malocclusions. They are also comfortable and the patients wear them full-time-inducing eating time. Occlusal forces transmitted through the dentition provide a constant proprioceptive stimulus to influence the rate of growth and the trabecular structure of the supporting bone. The features of Twin Blocks mean easier and quicker treatment. The occlusal inclined plane is the fundamental functional mechanism of the natural dentition. Twin blocks are bite blocks that effectively modify the occlusal inclined plane to induce favorably directed occlusal forces by causing a functional mandibular displacement. Upper and lower bite blocks interlock at a $45^{\circ}$ angle and are designed for full-time wear to take advantage of all functional forces applied to the dentition including the forces of mastication. The patients who were treated with modified Twin Blocks, and following results were observed: 1. Large overjet and deep overbite were corrected. 2. Class II molar relationship was changed into Class I. 3. Labial inclination of upper incisors was corrected by adjustment of labial bow of upper bite block. 4. The profiles of two patients were improved by anterior displacement of mandible.

• Proceedings of KOSOMES biannual meeting
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• 2017.11a
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• pp.15-15
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• 2017

• Smart Structures and Systems
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• v.31 no.3
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• pp.275-281
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• 2023

In recent years, technological developments have rapidly increased the number of complex structures and equipment in the industrial. Accordingly, the prognostics and health monitoring (PHM) technology has become significant. The safety assessment of industrial sites requires data obtained by installing a number of sensors in the structure. Therefore, digital twin technology, which forms the core of the Fourth Industrial Revolution, is attracting attention in the safety field. The research on digital twin technology of structures subjected to seismic loads has been conducted recently. Hence, this study proposes a digital twin system that estimates the responses and arbitrary load in real time by utilizing the minimum sensor to a pipe that receives a seismic and arbitrary load. To construct the digital twin system, a finite-element model was created considering the dynamic characteristics of the pipe system, and then updating the finite-element model. In addition, the calculation speed was improved using a finite-element model that applied the reduced-order modeling (ROM) technology to achieve real-time performance. The constructed digital twin system successfully and rapidly estimated the load and the point where the sensor was not attached. The accuracy of the constructed digital twin system was verified by comparing the response of the digital twin model with that derived by using the load estimated from the digital twin model as input in the finite-element model.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.886-889
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• 2006

Twin Auxiliary Electrodes were applied to the counter sustain electrode structure plasma display panels for the improvement of luminous efficiency. In advanced, we investigated the spatiotemporal behaviors of excited $Xe^{\ast\ast}(2p)$ atoms in that structure unit cell with various applied voltage conditions for the auxiliary electrodes. The near-IR emissions were observed by an ICCD camera combined with narrow band pass filter. As a partial result, the intensity of IR emissions and the response time were improved with the proposed twin auxiliary electrodes.

• Journal of Navigation and Port Research
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• v.42 no.2
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• pp.127-136
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• 2018

The motion response of floating structures is of significant concern in marine engineering. Floating structures can be disturbed by waves, winds, and currents that create undesirable motions of the vessel, therefore causing challenges to its operation. For a floating structure, mooring lines are provided in order to maintain its position; these should also produce a restoring force when the vessel is displaced. Therefore, it is important to investigate the tension of mooring lines and the motion responses of a twin barge when moored to guarantee the safety of the barge during its operation. It is essential to precisely identify the characteristics of the motion responses of a moored barge under different loading conditions. In this study, the motion responses of a moored twin barge were measured in regular waves of seven different wave directions. The experiment was performed with regular waves with different wavelengths and wave directions in order to estimate the twin-barge motions and the tension of the mooring line. In addition, the motion components of roll, pitch, and heave are completely free. In contrast, the surge, sway, and yaw components are fixed. In the succeeding step, a time-domain analysis is carried out in order to obtain the responses of the structure when moored. As a result, the Response Amplitude Operator (RAO) motion value was estimated for different wave directions. The results of the experiment show that the motion components of the twin barge have a significant effect on the tension of the mooring lines.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.1
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• pp.16-24
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• 2001

This paper presents an electromagnetic microactuator using the copper coil electroplated on the p+silicon diaphragm. The microactuator generates a vertical motion of the diaphragm using the radial direction, we propose a new actuator structure with twin magnets. The microactuator field in the radial direction, we propose a new actuator structure with twin magnets. The microactator shows a values of resonant frequency and quality factor in the ranges of 10.51${\pm}$0.22kHz and 46.6${\pm}$3.3, respectively. The twin magnet microactuator generates the maximum peak-to-peak amplitude of 4.4$\mu\textrm{m}$ for the AC rms current of 26.8mA, showing 2.4 times larger amplitude than the single magnet microactuator.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.1
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• pp.15-29
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• 2024

A fetoscope is an optical endoscope, which is often applied in fetoscopic laser photocoagulation to treat twin-to-twin transfusion syndrome. In an operation, the clinician needs to observe the abnormal placental vessels through the endoscope, so as to guide the operation. However, low-quality imaging and narrow field of view of the fetoscope increase the difficulty of the operation. Introducing an accurate placental vessel segmentation of fetoscopic images can assist the fetoscopic laser photocoagulation and help identify the abnormal vessels. This study proposes a method to solve the above problems. A novel encoder-decoder network with a dual-path structure is proposed to segment the placental vessels in fetoscopic images. In particular, we introduce a channel attention mechanism and a continuous convolution structure to obtain multi-scale features with their weights. Moreover, a switching connection is inserted between the corresponding blocks of the two paths to strengthen their relationship. According to the results of a set of blood vessel segmentation experiments conducted on a public fetoscopic image dataset, our method has achieved higher scores than the current mainstream segmentation methods, raising the dice similarity coefficient, intersection over union, and pixel accuracy by 5.80%, 8.39% and 0.62%, respectively.

• Journal of Internet Computing and Services
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• v.23 no.1
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• pp.39-47
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• 2022

Digital Twin is positioned as one of the establishment of a digital management system for core infrastructure in terms of collecting real data and implementing virtual space. However, there are currently no integrated three-dimensional marine information analysis tools and technologies in Korea, and unlike land, new 3D modeling technologies and data processing technologies are required to digitize flexible marine information, but there are limitations in implementation. Therefore, this study aims to present development directions in four areas: structure, data, modeling, and utilization platform of marine digital twin by analyzing trends related to marine digital twin and digital twin technology elements.