• Journal of the Korean Ceramic Society
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• v.49 no.1
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• pp.29-36
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• 2012

In many applications of functional oxides originally homogeneous materials are exposed to gradients in the chemical potential of oxygen. Prominent examples are solid oxide fuel cells (SOFCs) or oxygen permeation membranes (OPMs). Other thermodynamic potential gradients are gradients of electrical potential, temperature or uni-axial pressure. The applied gradients act as generalized thermodynamic forces and induce directed fluxes of the mobile components. These fluxes may lead to three basic degradation phenomena of the materials, which are kinetic demixing, kinetic decomposition, and morphological instabilities.

• Anatomy and Cell Biology
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• v.56 no.1
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• pp.61-68
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• 2023

Anatomical knowledge of the occipital condyle (OC) and its relationships to surrounding structures is important for avoiding injury during craniovertebral junction (CVJ) surgeries. This study was conducted to evaluate the morphology and morphometry of OC and its relationship to foramen magnum, jugular foramen (JF), and hypoglossal canal (HC). Morphometric parameters including length, width, height, and distances from the OC to surrounding structures were measured. The oval-like condyle was the most common OC shape, representing for 33.0% of all samples. The mean length, width and height of OC were 21.3±2.4, 10.5±1.4, and 7.4±1.1 mm, respectively. Moreover, OC was classified into three types based on its length. The most common OC length in both sexes was moderate length or type II (62.5%). The mean distance between anterior tips and posterior tips of OC to basion, and opisthion were 11.5±1.4, 39.1±3.3, 25.2±2.2, and 27.4±2.7 mm, respectively. The location of intracranial orifice of HC was commonly found related to middle 1/3 of OC in 45.0%. JF was related to the anterior 2/3 of OC in 81.0%, the anterior 1/3 of OC in 12.5%, and the entire OC length in 6.5%. These morphological analysis and morphometric data should be taken into consideration before performing surgical operation to avoid CVJ instability and neurovascular structure injury.

• Korean Journal of Applied Biomechanics
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• v.31 no.3
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• pp.168-175
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• 2021

Objective: To investigate the static and dynamic analysis of ankle joint complex between subjects with chronic ankle instability (CAI) and healthy controls. Method: A total of 38 subjects and CAI group (N=19) and healthy control (N=19) participated in this first study. Variables that were measured in this study were as follows: 1) Subtalar joint axis inclination and deviation 2) Rearfoot angle 3) Navicular drop test 4) Heel alignment view in alignment analysis. Intra Correlation Coefficient (ICC) is used for reliability. A secondary 17 subjects are recruited including 9 of CAI and healthy for gait analysis between group. Lower extremity sagittal, frontal, and transverse kinematics were measured. All data were analyzed to ensemble curve analysis. Results: 1) There were statistically significant differences in standing rearfoot, navicular drop, heel alignment view, subtalar joint (STJ) inclination and deviation. 2) Only in sagittal, meaningful difference is showed during walking in gait analysis. Conclusion: Morphological problem can affect ankle sprain in aspect of structure with no relation to compensation of neuromuscular.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.76.2-76.2
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• 2011

It is widely accepted that the SED of a galaxy relates to its morphology. In addition, the SED of the galaxy is closely connected to its star formation history, and its morphological properties are affected by the merger history, interactions with its environment, and the gravitational instability of its dynamical system. Thus, it is likely that star formation history correlates to the elements that determine morphological properties. Among the elements, this study investigates how much the merger histories of galaxies influence their star formation histories. By using simple merger trees and semi-analytic models, which disregard feedback processes to exclusively identify merger effects on star formation histories, we examine the relation between various merger histories and SEDs of galaxies. From the results, we discuss whether the SED of a galaxy can represent and constrain its merger history.

• Applied Microscopy
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• v.39 no.4
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• pp.365-371
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• 2009

This study was investigated to observe morphological changes of two pre-astronauts' hair, male and female by electron microscopy and to analyze its tensile strength by using rheometer. The surface of those two pre-astronauts' hair, which were very rough and irregular, contained separated scales and destroyed remnants of cuticular cells. Also, there were many holes on the cytoplasm of the cuticular cells which forms the cuticle layer. The destruction begins when the endocuticle where the holes form gets destroyed. And then, The tensile strength of female pre-astronaut's hair was 14.60 mm which is 10% reduced, compared to that of the normal healthy hair. Thus, this result thought to be due to the prolonged change of the biorhythm and psychological instability of the pre-astronauts.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.11-16
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• 2007

The existence of grooves on the surface of bond coat has significant effect on the instability of thermal barrier system. In this work, the thermal-mechanical fatigue experiments were performed under various thermal and mechanical loads for FeCralloy specimens with and without yttrium dopant to observe the deformation of surface grooves. The effect of temperature, fatigue load and the ratio of curvature on the deformation of grooves were investigated. As the results, it has been found that the higher load level and the higher curvature ratio induces the larger deformation near the grooves. However, the addition of yittrium dopant induces the adverse results.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.92-98
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• 2018

The effect of surfactants with different chain length on the drying dynamics of nanosized dispersion droplets and on the final morphology of the grains formed after water evaporation is investigated experimentally. An acoustic levitator was used to examine the drying dynamics of single droplets and SEM imaging was used to characterise the morphology of the final dried grains. Results show that the drying of drops with high molecular weight surfactants leads to more irregular grains and that the grain morphology is related to surface tension driven instability of the evaporating droplets which may lead to formation of hollow dried grains.

• Bulletin of the Korean Chemical Society
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• v.32 no.9
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• pp.3405-3410
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• 2011

We have investigated the cytotoxic potential of tellurium (Te) nanowires in BALB/3T3 fibroblast cells. Te nanowires were synthesized through an aqueous phase surfactant assisted method. Toxicological experiments, such as analysis of morphological changes, MTT assay, DAPI staining, and estimation of intracellular reactive oxygen species, were carried out to reveal the cytotoxic effects of Te nanowires. Te nanowires were found to be cytotoxic at all concentrations tested, in a dose-dependent manner. The UV/Vis spectra of Te nanowires suspended in a culture medium showed drastic changes and disappearance of two broad absorption peaks. The physicochemical properties such as, surface charge, size, and shape of Te nanowires were found to be altered during exposure of cells, due to the instability and agglomeration of nanowires in the culture medium. These results suggest that the chemical components of the DMEM medium significantly affect the stability of Te nanowires. In addition, TEM images revealed that necrosis was the basic pattern of cell death, which might stem from the formation of toxic moieties of tellurium, released from nanowire structures, in the bioenvironment. These observations thus suggest that Te nanomaterials may pose potential risks to environmental and human health.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1996.06a
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• pp.139-156
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• 1996

The phase field model is becoming the model of choice for the theoretical study of the morphologies of crystals growth from the melt. This model provides an alternative approach to the solution of the classical (sharp interface) model of solidification by introducing a new variable, the phase field, Ø, to identify the phase. The variable Ø takes on constant values in the bulk phases and makes a continuous transition between these values over a thin transition layer that plays the role of the classically sharp interface. This results in Ø being governed by a new partial differential equation(in addition to the PDE's that govern the classical fields, such as temperature and composition) that guarantees (in the asymptotic limit of a suitably thin transition layer) that the appropriate boundary conditions at the crystal-melt interface are satisfied. Thus, one can proceed to solve coupled PDE's without the necessity of explicitly tracking the interface (free boundary) that would be necessary to solve the classical (sharp interface) model. Recent advances in supercomputing and algorithms now enable generation of interesting and valuable results that display most of the fundamental solidification phenomena and processes that are observed experimentally. These include morphological instability, solute trapping, cellular growth, dendritic growth (with anisotropic sidebranching, tip splitting, and coupling to periodic forcing), coarsening, recalescence, eutectic growth, faceting, and texture development. This talk will focus on the fundamental basis of the phase field model in terms of irreversible thermodynamics as well as it computational limitations and prognosis for future improvement. This work is supported by the National Science Foundation under grant DMR 9211276

• Journal of the Korean Geotechnical Society
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• v.22 no.5
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• pp.83-91
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• 2006

Recently, the intensive rainstorm possibly induced by global warming plays a key role on the instability of railway adjacent slopes. The instability of slopes results as covering and loss of railway lines induced by slided soil mass. According to the site investigation on the failed slopes triggered by rainfall, low types of slope failure were observed: shallow, intermediate, gully erosion, and soil-rock interface failures. The observation reveals the different characteristics of slope failure depending on the thickness of soil layer, morphological features of slope, etc. Based upon the observations, flume tests were conducted to analyze the sliding mechanism of each failure. The variables of flume test are soil layer thickness, rainfall intensity, and morphology of slope under the constant condition of the percentage of fine, initial soil moisture content, slope angle and compaction energy. Test results show that shallow failure was mostly observed from the surface of the slope and caused by the soil erosion; in addition, compared to the other types of failure, the occurrence of initial erosion is late, however, the development of erosion is fast. In gully erosion failure, the collected water from the water catchment area helps erosion of the upper soil layer and transfer of residual corestone, which impedes the erosion process once the upper soil layers are eroded and corestone are exposed. The soil-rock interface failure shows the most fast initial erosion process among the failure types. Interestingly, the common feature observed from the different types of failure was the occurrence of the initial deformation near the toe of slopes which implies the existence of surbsurface flow along the downslope direction.