• Journal of the Korean Ceramic Society
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• v.36 no.11
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• pp.1252-1260
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• 1999

The defect chemistry and electrical characteristics of the grain boundaries of semiconducting SrTiO3 ceramics synthesized with wet-chemically surface-coated powders were investigated. The starting powders were separated into groups of 1-10${\mu}{\textrm}{m}$ 10-20${\mu}{\textrm}{m}$ etc by sedimentation and sieving methods. Na+ ions were absorbed on the powder surfaces by wet chemical-treatment method. The width of the grain boundary ranged up to several nm and the intergranular materials was amorphous. The additives coated on the surface of the powders were observed to be present at the grain boundaries of the ceramics. The diffusion depth of the additives into grains was about 30nm for the SrTiO3 ceramics synthesized with 5w/o coated materials, The threshold voltage grain boundary resistance and boundary potential barrier of the ceramics increased from 0.67V/cm 2.27k$\Omega$ and 0.05eV to 80.9V/cm 13.0k$\Omega$ 1.44eV with increasing the amount of the additives from 0 to 5 w/o respectively .

• Lingua Humanitatis
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• v.8
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• pp.265-289
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• 2006

The geographical characteristics of Yeongdong(永同) the southernmost part of the Chungcheongbukdo province, has attracted attention among the academic circle as one of the dialectal contact regions since it adjoins the Gyeongsang and Jeolla dialects. Unlike the local language in Mooju (Jellado dialect) adjacent to the Southwest part, the local language in Yeongdong is quite different from that of Kimcheon (Gyeongsang dialect). More specifically, it is noteworthy that the boundary line of the Gyeongsang dialect is found in this region, which is different from the administrative division. In other words, the local language in Yeongdong is divided into the Chungcheong dialect and the Gyeongsang dialect, and furthermore each dialect region still has the characteristics of the other region's dialect. For example, the phonological structure of Yeongdong Chungcheongdo dialect has very unique characteristics of the fudged dialect, which is seemingly influenced by the Gyeongsang dialect. The present study is to define the bottom boundary line of the southeast area of the Chungcheong dialect by identifying the boundary line between the Gyeongsang dialect and the Chungcheong dialect, and to clarify its specific sound system generated by the contact of these two dialects. For this, the author collected and analyzed data of the local language around Yeongdong and adjacent areas. It was found that Cheongwha-ri, Deokjin-ri, and Sanjeo-ri at Yeongsan-myeon, and Mugeunjeom, Sangga-ri, and Jungga-ri at Yeongdong-eup, among the regions that belongs to Chungcheong dialect within the local language of Yeongdong, show the characteristics of the Gyeongsang dialect. Accordingly, the western areas of these villages become the southeast boundary line of the Chungcheong dialect. Also, the unique phonological characteristics of the Yeongdong Chungcheong dialect is affected by the Gyeongsang dialect, among which "rhythms, y deletion, nasal phoneme deletion, and w deletion" appeared. It is thought to be the unique fudged dialectal phenomenon that appeared only in this region. The research result is expected to be of some help in finding out various aspects of dialectal contacts as well as clarifying the phonological features of the local language in Yeongdong, and thereby contributing to exact divisioning of the Chungcheong dialect.

• International Journal of Aeronautical and Space Sciences
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• v.6 no.1
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• pp.1-7
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• 2005

The inlet boundary condition of computations about the supersonic turbine flow is commonly applied as far-field inlet boundary condition with specified velocity. However, the inflow condition of supersonic turbine is sometimes affected by the shocks or expansion waves propagated from leading edges of blade. These shocks and expansion waves alter the inlet boundary condition. In this case, the inlet boundary condition can not be specified Therefore, in this paper, numerical analyses for three different inlet conditions - fa-field inlet boundary condition, inlet boundary condition with a linear nozzle and inlet boundary condition with a converging-diverging nozzle - have been performed and compared with experimental results to solve the problem. It is found that the inlet condition with a linear nozzle or a converging-diverging nozzle can prevent changing of inlet boundary condition, and thus predict more accurately the supersonic flow within turbine cascade than a far-field inlet boundary condition does.

• International Journal of Aeronautical and Space Sciences
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• v.13 no.1
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• pp.43-57
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• 2012

In a modern aircraft, there are many variations in its mass, stiffness, and aerodynamic characteristics. Recently, an analytical approach was proposed, and this approach uses the idea of uncertainty to find out the most critical flight flutter boundary due to the variations in such aerodynamic characteristics. An analytical method that has been suggested to predict robust stability is the mu method. We previously analyzed the robust flutter boundary by using the mu method, and in that study, aerodynamic variations in the Mach number, atmospheric density, and flight speed were taken into consideration. The authors' previous attempt and the results are currently quoted as varying Mach number mu analysis. In the author's previous method, when the initial flight conditions were located far from the nominal flutter boundary, conservative predictions were obtained. However, relationships among those aerodynamic parameters were not applied. Thus, the varying Mach number mu analysis results required validation. Using an optimization approach, the varying Mach number mu analysis was found out to be capable of capturing a reasonable robust flutter boundary, i.e., with a low percentage difference from boundaries that were obtained by optimization. Regarding the optimization approach, a discrete nominal flutter boundary is to be obtained in advance, and based on that boundary, an interpolated function was established. Thus, the optimization approach required more computational effort for a larger number of uncertainty variables. And, this produced results similar to those from the mu method which had lower computational complexity. Thus, during the estimation of robust aeroelastic stability, the mu method was regarded as more efficient than the optimization method was. The mu method predicts reasonable results when an initial condition is located near the nominal flutter boundary, but it does not consider the relationships that are among the aerodynamic parameters, and its predictions are not very accurate when the initial condition is located far from the nominal flutter boundary. In order to provide predictions that are more accurate, the relationships among the uncertainties should also be included in the mu method.

• Kyungpook Mathematical Journal
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• v.49 no.2
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• pp.321-348
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• 2009

In this paper, we give two lower bounds on the diameter of the boundary slope set of a Montesinos knot. One is described in terms of the minimal crossing numbers of the knots, and the other is related to the Euler characteristics of essential surfaces with the maximal/minimal boundary slopes.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.11
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• pp.2059-2071
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• 1992

The characteristics of wave propagation along a catenary in rail electrification system depend on the boundary impedance, characteristic impedance of catenary, and the contact force of pantograph moving along the catenary. In this study, the wave propagation along catenary is studied with arbitrary boundary conditions and characteristic impedance of catenary. The reflection and transmission of waves through the boundaries of catenary and the propagation of waves along the catenary are found to be dependent on the wave length.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.480-485
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• 2004

If a wall separates the bounded and unbounded spaces, then the wall's role in transporting the acoustic characteristics of the two spaces is not well defined. In this paper, we attempted to see how the acoustic characteristical of two spaces are really affected by the spatial characteristics of the wall. In order to understand coupling mechanism, we choose a finite space and a semi-infinite space separated by the flexible or rigid wall and an opening. A volume interaction can be occurred in structure boundary and a pressure interaction can be happened in the opening boundary. For its simplicity, without loosing generality, we use rather simplified rectangle model instead of generally shaped model. The source impedance is presented to the various types of boundaries. The distributions of pressure and active intensity are also presented at the cavity and structure-dominated modes. The resulting modification, shifts of mode1 frequencies and changing of standing wave patterns to satisfy both coupled boundary conditions and governing equations, are presented.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.653-660
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• 2012

In this paper free vibration analysis of symmetric and cross-ply elastic laminated shells based on FSDT with two different boundary conditions(C-C, S-S) was performed through discretization of equations of motion and boundary condition. Model of laminated composite cylindrical shells subjected to a combination of magnetic and thermal fields is developed via Hamilton's variational principle. These coupled equations of motion are based on the electromagnetic equations (Faraday, Ampere, Ohm, and Lorenz equations) and thermal equations which are involved in constitutive equations. Variations of dynamic characteristics of composite shells with applied magnetic field, temperature gradient, and stacking sequence for each boundary conditions are investigated and pertinent conclusions are derived.

• Speech Sciences
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• v.14 no.2
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• pp.139-155
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• 2007

Old Korean regulated poems have a typical prosodic structure characterized by a pitch contour. This work applies Jun's finding in Seoul Korean(Jun 1993, 2000, 2005) to old Korean regulated poems, and reports some other significant phonetic characteristics, arguing that old Korean regulated poems have a regular rhythm based on the pitch contour implementing the typically hierarchical prosodic structure. The major prosodic units defined are a foot, a phrase, and a line. Next, this work proposes pitch contour characterizing prominence in a unit, boundary tones, and pauses at the boundary position, as the basic and significant cues of rhythm of a Korean poem. Specifically, some significant characteristics are discussed as follows: first, the tonal pattern of a foot is HL, starting high and ending low; second, the lowering boundary tones of HL% and L% are perceived at the end of a phrase and a line; and finally, a gradient degree of pause is observed at each unit-final position.

• Korean Institute of Interior Design Journal
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• v.14 no.5 s.52
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• pp.26-34
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• 2005

The systematic way of the boundary thought in Buddhism, when applied to the principles of building, determines certain forms to certain temples, and organizes their topological boundary concept structure - the continuous experience of the visitor from his/her entry bridge(connecting), through the main temple gate(neighbourhood), pavilion gate(including), stairs(continuance), to the arrival at the pavilion of the god of a mountain(spiral), which reconstitutes the Buddhist boundary symbolism and philosophy. The topological boundary spaces of temples are an architectural manifestation of Buddhism's Mahayana boundary concept aspects, whose object is to play a productive and active role in the enlightenment of people, serving the very basic end of the religion. The disciplined topological boundary spaces of the temple, as a reification of the boundary symbolisms of Buddhist topological cosmology, corresponds to Buddha-Ksetra, the highest state of existence in the universe. Visitors to the temple are invited to participate in the world of abundant Buddhist boundary concept symbols, and through this process, is enabled to elevate oneself to the transcendent topological boundary world and have a simulated experience of liberation.