• Honam Mathematical Journal
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• v.30 no.4
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• pp.603-616
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• 2008

A generalized n-dimensional Riemannian manifold $X_n$ on which the differential geometric structure is imposed by the unified field tensor $^*g^{{\lambda}{\nu}}$, satisfying certain conditions, through the $^*g$-ME-connection which is both Einstein's equation and of the form(3.1) is called $^*g$-ME-manifold and we denote it by $^*g-MEX_n$. In this paper, we prove a necessary and sufficient condition for the existence of $^*g$-ME-connection and derive a surveyable tensorial representation of the $^*g$-ME-connection and the $^*g$-ME-vector in $^*g-MEX_n$.

• Journal of Advanced Navigation Technology
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• v.2 no.1
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• pp.11-21
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• 1998

There have been active research efforts in the development of a dual-use millimeter-wave radiometer as an aircraft landing aid in low visibility conditions. In this paper, we constructed a radiometer operating at the Ka-band where it is relatively easy to build RF components. The radiometer is used to collect radiometric signatures of some vehicles and land surfaces. Measured signatures suggest that vehicles with metallic surfaces yield signatures markedly different from nearby land surfaces so that they can easily be detected by a simple radiometer.

• Journal of the Chungcheong Mathematical Society
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• v.27 no.4
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• pp.697-705
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• 2014

For a complex measure ${\mu}$ on B and $f{\in}L^2_a(B)$, the Toeplitz operator $T_{\mu}$ on $L^2_a(B,dv)$ with symbol ${\mu}$ is formally defined by $T_{\mu}(f)(w)=\int_{B}f(w)\bar{K(z,w)}d{\mu}(w)$. We will investigate properties of the Toeplitz operator $T_{\mu}$ with symbol ${\mu}$. We define the Toeplitz type operator $T^r_{\psi}$ with symbol ${\psi}$, $$T^r_{\psi}f(z)=c_r\int_{B}\frac{(1-{\parallel}w{\parallel}^2)^r}{(1-{\langle}z,w{\rangle})^{n+r+1}}{\psi}(w)f(w)d{\nu}(w)$$. We will also investigate properties of the Toeplitz type operator with symbol ${\psi}$.

• Bulletin of the Korean Chemical Society
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• v.30 no.6
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• pp.1337-1340
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• 2009

Electrical properties of a fluorinated carbon black (CB)-filled high-density polyethylene (HDPE) polymeric switch were investigated as a function of fluorination pressure at 0.1 ~ 0.4 MPa. From the FT-IR results, the absorption spectra of the fluorinated CB show an absorption band at 1400 ~ 1000 $cm^{-1}\;for\;{\nu}_{C-F}$ and the peak intensity increased with increasing fluorination pressure. Also, the analysis of XPS spectra of the fluorinated CB indicated that fluorine content increased with increasing fluorination pressure. Meanwhile, the surface free energy of the fluorinated CB decreased with increasing fluorination pressure. Consequently, the increase of fluorine contents of CB made a disappearance of negative temperature coefficient (NTC) behavior of the polymeric switch, which was probably due to the reduction of CB reaggregation after melting point of the HDPE, resulted from the decreasing of London dispersive component of the surface free energy for CB particles.

• Applied Science and Convergence Technology
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• v.23 no.1
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• pp.1-13
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• 2014

Semiconductor quantum structures are often characterized by their energy gaps which are modified by the quantum size effect. Energy levels in semiconductors can be realized by optical transitions within confined structures. Photoluminescence spectroscopy in magnetic fields at low temperatures has proved to be a powerful technique for investigating the electronic states of quantum semiconductor heterostructures and offers a complimentary tool to electrical transport studies. In this review, we examine comprehensive investigations of magneto-excitonic and Landau transitions in a large variety of undoped and doped quantum-well structures. Strong magnetic fields change the diamagnetic energy shift of free excitons from quadratic to linear in B in undoped single quantum well samples. Two-dimensional electron gas induced by modulation doping shows pronounce quantum oscillations in integer quantum Hall regime and discontinuous transition at ${\nu}=1$. Such discontinuous transition can be explained as the formation of spin waves or Skyrmions.

• Journal of Sensor Science and Technology
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• v.27 no.6
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• pp.403-406
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• 2018

We have investigated a fiber-optic sensor for detecting the hydrogen gas dissolved in insulation oil based on a palladium (Pd)-coated fiber Bragg grating (FBG). As the palladium absorbs the hydrogen gas dissolved in the insulation oil, its volume expands and the Bragg wavelength shifts to a longer wavelength. The experimental results showed that the Bragg wavelength of FBG increased to 70 nm when the concentration of hydrogen dissolved in the insulation oil was 409 ppm.

• Journal of Audiology & Otology
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• v.25 no.1
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• pp.55-58
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• 2021

Sensorineural hearing loss (SNHL) is seldom associated with Wernicke encephalopathy (WE) or thiamine deficiency. While thiamine deficiency and repletion are often considered prior to dextrose infusions in patients with chronic alcohol abuse to prevent WE, they are often overlooked in non-alcoholic patients who are also at risk for malnutrition. In this paper we describe a case of a non-alcoholic 28-year-old female status post-sleeve gastrectomy who developed SNHL in the setting of thiamine deficiency and WE, with ongoing hearing impairment requiring hearing aids despite thiamine repletion.

• Korean Journal of Audiology
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• v.25 no.1
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• pp.55-58
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• 2021

Sensorineural hearing loss (SNHL) is seldom associated with Wernicke encephalopathy (WE) or thiamine deficiency. While thiamine deficiency and repletion are often considered prior to dextrose infusions in patients with chronic alcohol abuse to prevent WE, they are often overlooked in non-alcoholic patients who are also at risk for malnutrition. In this paper we describe a case of a non-alcoholic 28-year-old female status post-sleeve gastrectomy who developed SNHL in the setting of thiamine deficiency and WE, with ongoing hearing impairment requiring hearing aids despite thiamine repletion.

• Journal of the Korean Institute of Navigation
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• v.17 no.3
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• pp.85-92
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• 1993

In connection to the design of high speed vessels, the numerical simulation is carried out to make clear the property of flows and breaking phenomena around the catamaran. It is because the bradking phenome-non is closely related to the free-surface turbulent flow. The free-surface wave and transverse velocity vectors are calculated around the twin and demi hull of the catamaran. Computed results are applied to detect the appearance of sub-breaking waves around the hull. The critical condition for their appearance is studied at two Froude numbers of 0.45 and 0.95. The nu-merical analysis shows that the breaking is more serious near the twin hull rather the demi hull. To simu-late the flows, the Navier-Stokes solver is invoked with a free-surface. The computation is made only in half a domain because it is symmetric in the shape.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2006.11a
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• pp.269-274
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• 2006

The purposes of this research are, first, to investigate the present condition of indoor thermal environment in winter. Second, to find out how residents' knowledge, consciousness, and behavior changed after provided with education and information of indoor climate. Finally, to reveal how this changes make alteration to their indoor environment. Thirty apartments were collected, and then divided into three groups as Control Group, Education Group, and Edu-information Group in order to conduct the purposes. Provided education and environmental information turn out to have a positive effect to residents' knowledge, consciousness, and behavior, and consequently, it leads residents to control their indoor environment more actively in some cases. Thus, it is important to provide residents with environmental education and information, and it should be conducted regularly in order to maximize the positive effect of education since it tends to decrease as time goes by.