• Journal of the korean academy of Pediatric Dentistry
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• v.1 no.1
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• pp.49-55
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• 1974

Electromyographic studies were performed on the action of the masseter muscles. Among the children aged from 6 to 8 years, ten children with normal occlusion and another ten with space maintainer were selected. The children were divided into 3 groups. They were: 1) A group: Children who removed space maintainer 2) B group: Children who inserted space maintainer 3) C group: Children with normal occlusion. The electromyogram was recorded with 4 channel polygraph. (Grass model VII) Electrodes which were cup-typed gold disks, 9 millimeters in the diameter, were located on the superficial layer of masseter muscles. The electromyogram was recorded in the physiologic rest position, molar occlusion, chewing movement, protraction, left lateral movement, and right lateral movement. The conclusions were as follows. 1. In the physiologic rest position, lateral movement, the electrical potentials of the masseter muscles were not changed clearly in each groups. 2. In molar occlusion, chewing movement, The electrical potentials of the masseter muscles of the B group were almost 10% higher than those of A group, and were almost 60-70% in comparision with C group. 3. In protraction, the electrical potentials of the masseter muscles of the B group were almost 40% higher than those of A group, and were almost equal to C group. 4. The electrical activities of the masseter muscles in the mandibular movements were in the following order: (1) Molar occlusion (2) Chewing movement (3) Protraction (4) Lateral movement.

• Journal of IKEEE
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• v.24 no.4
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• pp.1039-1049
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• 2020

Neural decoding is important to recognize the user's intention for controlling a neuro-prosthetic hand. This paper proposes a real-time decoding method for multi-channel peripheral neural activity. Peripheral nerve signals were measured from the median and radial nerves, and motion artifacts were removed based on locally fitted polynomials. Action potentials were then classified using a k-means algorithm. The firing rate of action potentials was extracted as a feature vector and its dimensionality was reduced by a self-organizing feature map. Finally, a multi-layer perceptron was used to classify hand motions. In monkey experiments, all processes were completed within a real-time constrain, and the hand motions were recognized with a high success rate.

• JSTS:Journal of Semiconductor Technology and Science
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• v.11 no.2
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• pp.111-120
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• 2011

A two-dimensional analytical model for deriving the threshold voltage of a short channel fully depleted (FD) cylindrical/surrounding gate MOSFET (CGT/SGT) is suggested. By taking into account the lateral variation of the surface potential, introducing the natural length expression, and using the Bessel functions of the first and the second kinds of order zero, we can derive potentials in the gate oxide layer and the silicon core fully two-dimensionally. Making use of these potentials, the minimum surface potential can be obtained to derive the threshold voltage as a closed-form expression in terms of various device parameters and applied voltages. Obtained results can be used to explain the drain-induced threshold voltage roll-off of a CGT/SGT in a unified manner.

• Korean Journal of Metals and Materials
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• v.46 no.10
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• pp.652-661
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• 2008

Reduction of NOx in emission gas, improvement of engine efficiency, and extension of warranty period has made demands for developing materials more corrosively resistant to the inner-muffler environments or predicting the lifetime of materials used in muffler more precisely. The corrosion inside muffler has been explained with condensate corrosion mainly though thermal oxidation experiences prior to condensate corrosion. Hence, the aim of this study is to describe how the thermal oxidation affects the corrosion of stainless steel exposed to the inner-muffler environments. Auger electron spectroscopy and electrochemical tests were employed to analyze oxide scale and to evaluate corrosion resistance, respectively. Thermal oxidation has different role of condensate corrosion depending on the temperature: inhibiting condensate corrosion below $380^{\circ}C$ and enhancing condensate corrosion above $380^{\circ}C$. The low temperature oxidation causes to form compact oxide layer functioning a barrier for penetrating condensate into a matrix. Although though thermal oxidation caused chromium-depleted layer between oxide layer and matrix, the enhancement of the condensate corrosion in high temperature oxidation resulted from corrosion-induced crevice formed by oxide scale rather than corrosion in chromium-depleted layer. It was proved by aids of anodic polarization tests and measurements of pitting corrosion potentials. By the study, the role of high temperature oxidation layer affecting the condensate corrosion of stainless steels used as muffler materials was well understood.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.2
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• pp.242-247
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• 1987

Electrophysical phenomena at the silicon semiconductor-electrolyte solution interfaces were analyzed based on the zeta potential of the electrical double layer and microelectrophoresis. The suspensions were composed of the p or n-type silicon particles suspended in the KCI or pH buffer solutions. The approximate diameter of the prepared and sampled sioicon semiconductor pardticles was 1.5\ulcorner. The sign of the zeta poetntials of the p and n-type silicon particles in the KCl and pH buffer solution was positive. A range of electrophoretic mobilities of the p and n-type silicons in the KCl solutions was 5.5-8.9x10**-4 cm\ulcornerV-sec and 4.2-7.9x10**-4cm\ulcornerV-sec, respectively. The range of zeta potentials corresponding to the electrophoretic mobilities is 70.4-114.0mV nad 53.9-101.2mV, respectively. On the other hand, a range of electrophoretic mobilities of the p and n-type silicons in the pH buffer solutions was 1.1x10**-4-2.2x10**-3cm\ulcornerV-sec and 0-2.1x10**-3cm\ulcornerV-sec, respectively. The range of zeta potentials corresponding to the electrophoretic mobilities is 14.1-281.6mV and 0-268.8mV, respectively. The zeta potentials and electrical double layers of the doped silicon semiconductors are decisively influenced by the positively charged ions in the solutions. The maximum values of the zeta potentials in the KCl solutions appeared at a concentration of about 10-\ulcorner. The isoelectric point of the n-type silicon semiconductors appeared at about a pH 7. The effect of the space charge of the doped silicon semiconductors can be neglected compare with the effect of the surface charge.

• Bulletin of the Korean Chemical Society
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• v.32 no.6
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• pp.2045-2050
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• 2011

Using first principles density functional theory the formation energies of various binary compounds of lithium graphite and its homologues were calculated. Lithium and graphite react to form $Li_1C_6$ (+141 mV) but not form $LiC_4$ (-143 mV), $LiC_3$ (-247 mV) and $LiC_2$ (-529 mV) because they are less stable than lithium metal itself. Properties of structure and reaction potentials of $C_5B$, $C_5N$ and $B_3N_3$ materials as iso-structural graphite were studied. Boron and nitrogen substituted graphite and boron-nitrogen material as a iso-electronic structured graphitic material have longer graphene layer spacing than that of graphite. The layer spacing of $Li_xC_6$, $Li_xC_5B$, $Li_xC_5N$ materials increased until to x=1, and then decreased until to x=2 and 3. Nevertheless $Li_xB_3N_3$ has opposite tendency of layer spacing variation. Among various lithium compositions of $Li_xC_5B$, $Li_xC_5N$ and $Li_xB_3N_3$, reaction potentials of $Li_xC_5B$ (x=1-3) and $Li_xC_5$ (x=1) from total energy analyses have positive values against lithium deposition.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.33 no.2
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• pp.105-110
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• 2007

The stability of titanium dioxide dispersion was evaluated by zeta ($\zeta$) potential and we intended to apply it for improvement of dispersion stability. Both theories related to $\zeta$ potential (electric double layer, electrophoresis, isoelectric point and electroosmosis) and a method to measure $\zeta$ potential were explained in this study. The change in $\zeta$ potential of $TiO_2$ dispersion was measured by means of Henry's function of Helmholtz-Smoluchowski's equation (H-S equation). The $\zeta$ potentials of $TiO_2$ dispersion were negative in all measured pH values ($3.0{\sim}9.0$), and absolute values of $\zeta$ potentials of $TiO_2$ increased as pH values increased. $TiO_2$ dispersion was maintained in pH 8.0 and 9.0 respectively. From these results, we suggest that $\zeta$ potentials have an effect on $TiO_2$ dispersion and absolute value of $\zeta$ potentials played an important role in the stability of $TiO_2$ dispersion in aqeous medium.

• Journal of the Korean Society of Safety
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• v.9 no.1
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• pp.140-145
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• 1994

Contributions of global warming potentials on CFC(Chlorofluorocarbon) and Ozone were calculated by Stefan-Boltzmann's law and environmental effects of its were discussed. As the greenhouse effect on the unit volume of CFC is the most strong in the infrared gases and the destruction of Ozone in stratosphere is also depends on CFC, therefore release of CFC should be prohibited. But the effect of restriction on CFC will be appeared more than 10 years later. Eventhough the Ozone layer is related to global warming, It should be protected because of maitaining food chain mode of life, preventing human disease, for example, cataract, dermatics etc.

• Journal of the Korean Mathematical Society
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• v.38 no.4
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• pp.781-791
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• 2001

We consider the inverse conductivity problem to identify the unknown conductivity $textsc{k}$ as well as the domain D. We show hat, unlike the case when $textsc{k}$ is known, even a two or three dimensional ball may not be identified uniquely if the conductivity constant $textsc{k}$ is not known. We find a necessary and sufficient condition on the Cauchy data (u│∂Ω, g) for the uniqueness in identification of $textsc{k}$ and D. We also discuss on failure of stability.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2611-2616
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• 2011

We studied the physical properties of the mercaptopyruvic-acid layer formed on gold surfaces, which has the interactions with the titanium dioxide surface for design of gold- titanium dioxide distribution. Surface force measurements were performed, using the atomic force microscope (AFM), between the surfaces as a function of the salt concentration and pH value. The forces were analyzed with the DLVO (Derjaguin-Landau-Verwey-Overbeek) theory, to evaluate the potential and charge density of the surfaces quantitatively for each salt concentration and each pH value. The difference in the properties reflected the effect of the isoelectric point on the surface forces. The forces were interpreted for the evaluation with the law of mass action and the ionizable groups on the surface. The salt concentration dependence of the surface properties, found from the measurement at pH 8.0, was consistent with the prediction from the law. It was found that the mercaptopyruvic-acid layer had higher values for the surface charge densities and potentials than the titanium dioxide surfaces at pH 8, which may be attributed to the ionized-functional-groups of the mercaptopyruvic-acid layer.