• Radiation Oncology Journal
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• 제13권2호
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• pp.199-203
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• 1995

Purpose: To evaluate the dose under lung block as a function of depth and the effectiveness of a block as a function of block width. Materials and Methods : Field size of mantle field was $22.8{\times}32.4cm^2.$ Dose distribution of the mantle field was measured with two dimensional water phantom system. To analyze the effectiveness of the lung block. central axis plane, 5cm off-axis plane, and 10cm off-axis plane were studied. Results: The dose under the lung block was recorded with maximum at the depth between 5cm and 10cm. In the central axis plane, dosimetric block width was $10-15\%$ less than physical block width. In the 5cm off-axis plane, dosimetric block width was $4-9\%$ less than physical block width. In the 10cm off-axis plane, dosimetric block width was $2\%$ less than physical block width. Conclusion: Depth dependence of the dose under the lung block was founded. Also, block width dependence of the lung block was founded. To induce the accurate relation between the physical block width and the 'effective' block width, it needs more detailed understanding of the variables involved.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.498-501
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• 2006

When an object or objects, rigid or flexible, presents in incident sound field, the sound wave is scattered. This, we call, is scattered sound field. It, of course, depends on the amplitude and the direction of the incident sound field as well as the geometry and the surface impedance of the scatterer(object). This paper addresses the way to measure scattered sound field by using arbitrary incident sound wave. This means that the method can decompose the scattered field from measured sound field with respect to any magnitudes and directions of incident plane-waves.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기물성,응용부문
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• pp.219-223
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• 2001

In this paper, electromagnetic waves were measured in accordance with propagating the discharge when positive and negative DC high voltage was applied to needle-plane electrdes and plane-plane electrdes that solid dielectric was inserted between the electrodes. The radiated electromagnetic waves were investigated in bandwidth of VHF($30{\sim}230$[MHz]) using an biconical antenna. In needle-plane electrodes high electric field intensity is shown in both frequency band of 90(MHz) and 170[MHz], and gradually decreasing characteric is appeared at high frequency band. However high electric field intensity is shown in both 80[MHz] and 140[MHz] in case of plane-plane electrodes configuration. And over 150[MHz] frequency band, rapidly decreasing characteristic is shown. Moreover, electric field intensity of positive DC is about $5{\sim}10$[dB] higher than negative DC.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.943-946
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• 2007

In-plane piezoelectric charge constant of Electro-Active paper (EAPap) was investigated based on direct and converse piezoelectric effects. EAPap samples were made with cellulose film with very thin gold electrode coated on both sides of the film. To characterize direct piezoelectricity of EAPap, induced charge was measured when mechanical stress was applied to EAPap. In-plane piezoelectric charge constant was extracted from the relation between induced charge and applied in-plane normal stress. To investigate converse piezoelectricity, induced in-plane strain was measured when electric field was applied to EAPap. Piezoelectric charge constant was also extracted from the relation of induced in-plane strain and applied electric field. Piezoelectric charge constants obtained from direct and converse piezoelectricity are 31 pC/N and 178 x 10-12m/V for 45 degree sample, respectively. Measured piezoelectric charge constants of EAPap provide promising potential as a piezoelectric material.

• 대한기계학회논문집A
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• 제32권2호
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• pp.148-161
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• 2008

A volume integral equation method (VIEM) is used to calculate the plane elastostatic field in an isotropic elastic half-plane containing multiple isotropic or anisotropic inclusions subject to remote loading. A detailed analysis of stress field at the interface between the matrix and the central inclusion in the first column of square packing is carried out for different values of the distance between the center of the central inclusion in the first column of square packing of inclusions and the traction-free surface boundary in an isotropic elastic half-plane containing multiple isotropic or anisotropic inclusions. The method is shown to be very accurate and effective for investigating the local stresses in an isotropic elastic half-plane containing multiple isotropic or anisotropic inclusions.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 가을 학술발표회 논문집
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• pp.513-520
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• 2002

The stability analysis of rock slope can be predicted using a suitable field data but it cannot be predicted unless suitable field data was taken. In this study, artificial neural networks theory is applied to predict plane failure that has a few data. It is well known that human brain has the advantage of handling disperse and parallel distributed data efficiently. On the basis of this fact, artificial neural networks theory was developed and has been applied to various fields of science successfully In this study, error back-propagation algorithm that is one of the teaching techniques of artificial neural networks is applied to predict plane failure. In order to verify the applicability of this model, a total of 30 field data results are used. These data are used for training the artificial neural network model and compared between the predicted and the measured. The simulation results show the potentiality of utilizing the neural networks for effective safety factor prediction of plane failure. In conclusion, the well-trained artificial neural network model could be applied to predict the plane failure stability of rock slope.

• 대한기계학회논문집B
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• 제24권7호
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• pp.924-929
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• 2000

This paper addresses a new technique of measuring the mean flow velocity over the cross sectional area of the pipe using sound field reconstruction. When fluid flows in the pipe and two plane waves propagate oppositely through the medium, the flow velocity causes the change of wave number of the plane waves. The wave number of the positive going plane wave decreases and that of negative going one increases in comparison to static medium in the pipe. Theoretical backgrounds of this method are introduced in detail and the measurement of mean flow velocity using the sound field reconstruction is not affected by velocity profile upstream of microphones.

• 대한수학회보
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• 제54권3호
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• pp.975-992
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• 2017

In this article, we consider a real hypersurface of complex two-plane Grassmannians $G_2({\mathbb{C}}^{m+2})$, $m{\geq}3$, admitting commuting ${\ast}$-Ricci and pseudo anti-commuting ${\ast}$-Ricci tensor, respectively. As the applications, we prove that there do not exist ${\ast}$-Einstein metrics on Hopf hypersurfaces as well as ${\ast}$-Ricci solitons whose potential vector field is the Reeb vector field on any real hypersurfaces.

• Journal of Magnetics
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• 제11권2호
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• pp.66-69
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• 2006

Local magnetization reversal in the exchange-biased NiFe/FeMn and $[Pd/Co]_5/FeMn$ multilayers with in-plane and out-of-plane magnetic anisotropy was achieved by using laser annealing. The local annealed NiFe/FeMn film under the opposite magnetic field shows a magnetoresistance (MR) curve having two symmetric peaks at the positive and negative exchange biasing field (${\pm}H_{ex}$). The intensity of the nucleated MR peak rises as the exposed area extends during the laser annealing process, and the peak disappears under the reverse magnetic field. In the case of [Pd/Co]/FeMn films, the local magnetization reversal increased gradually as the laser power increases. The locally reversed magnetization was restored under the opposite magnetic field.

• 한국가시화정보학회지
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• 제19권1호
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• pp.36-42
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• 2021

This study measured the velocity of magnetic particles inside the power generation using external heat sources. Single Plane Illumination Microscopy (SPIM) was used to measure magnetic particles that are simultaneously affected by bubbly flow and magnetic field. It has the advantage of reducing errors due to particle superposition by illuminating the thin light sheet. The hydraulic diameter of the power generation is 3mm. Its surface is covered with a coil with a diameter of 0.3 mm. The average diameter of a magnetic particle is 200nm. The excitation and emission wavelengths are 530 and 650nm, respectively. In order to find out the flow characteristics, a total of four velocity fields were calculated in wide and narrow gap air bubbles, between the wall and the air bubble and just below the air bubble. Magnetic particles showed up to 8.59% velocity reduction in the wide gap between air bubbles due to external magnetic field.