• Journal of Korean Ophthalmic Optics Society
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• v.18 no.3
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• pp.321-327
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• 2013

Purpose: To investigate a correlation between vertical fixation disparity and stereopsis by analyzing distribution of types of vertical fixation disparity. Methods: In this study, RANDOT(R) stereotest partly using random dot was used in stereopsis tests. The vertical fixation disparity in close proximity categorized fixation disparity slope into six types on the basis of the result of measurement in when two thin lines, one for one eye looks, become overlapped as a line by adding into prism with Wesson fixation disparity card while maintaining a distance of 25 cm from patients. Results: In the types of near vertical fixation disparity curve, targeting 43 people, the first type 55.82% was the most distributed, the second type is the least 23.25%, the third type of 4.65%, the fourth type of 4.65%, the fifth type of 6.98%, the sixths types of 4.65% were distributed. The result of a correlation analysis, which shows the degree of linear correlation between two variables, represented that stereopsis is not correlated with Y-intercept (r = -0.07) which show vertical fixation disparity, associated phoria (r = -0.03) and dissociated phoria (r = -0.00), but it was not statistically significant (p>0.05). Fixation disparity slope of vertical fixation disparity (r = 0.36) was shown to have a positive correlation with stereopsis. It has a low positive correlation and a meaningful statistics (p<0.05). The Y-intercept which indicates vertical fixation disparity was also not associated with stereopsis (r = -0.07) and dissociated phoria (r = -0.03), and this was not statistically significant (p>0.05), while it had a high correlation as well as a statistically significant with associated phoria (r = 0.89). There was a negative correlation between Y-intercept and fixation disparity slope of vertical fixation disparity (r = -0.33). It showed a low relationship but statistically valuable (p>0.05). As a result of regression analysis, the stereopsis was changed as 7.631" if vertical fixation disparity changes 1' and the vertical fixation disparity changed as 0.017' if stereopsis changes 1', and the change was statistically significant (p<0.05). Conclusions: The study shows that there is a low correlation between stereopsis and vertical fixation disparity, and it is difficult to determine stereopsis only using vertical fixation disparity. Therefore, it suggests other factors above vertical fixation disparity have greater influence on stereopsis.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.2
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• pp.257-268
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• 2014

In this study, flow-driven rotor simulations with a given load are conducted to analyze the operational characteristics of a vertical-axis Darrieus turbine, specifically its self-starting capability and fluctuations in its torque as well as the RPM. These characteristics are typically observed in experiments, though they cannot be acquired in simulations with a given tip speed ratio (TSR). First, it is shown that a flow-driven rotor simulation with a two-dimensional (2D) turbine model obtains power coefficients with curves similar to those obtained in a simulation with a given TSR. 3D flow-driven rotor simulations with an optimal geometry then show that a helical-bladed turbine has the following prominent advantages over a straight-bladed turbine of the same size: an improvement of its self-starting capabilities and reduced fluctuations in its torque and RPM curves as well as an increase in its power coefficient from 33% to 42%. Therefore, it is clear that a flow-driven rotor simulation provides more information for the design of a Darrieus turbine than a simulation with a given TSR before experiments.

• Korean Journal of Optics and Photonics
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• v.7 no.3
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• pp.266-271
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• 1996

In this study the evaluation of RWG MQW-LD fabricated with our vertical LPE system has been carried out with measuring its optical characteristics. This laser diode operated in lateral single mode as designed, and it showed 77% of internal quantum efficiency, 18cm of internal loss and 5.5$\AA$/$^{\circ}C$ of the thermal characterictic of the lasing wavelength. From these results we conclude that the vertical LPE system are fairly good and it might he useful to fabricate MQW wafer for laser diode.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.507-510
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• 2007

Piston cores retrieved from the western Ulleung Basin, East Sea were analyzed to examine the potential for hydrocarbon generation and to determine the hydrocarbon indicators. 2D multi-channel reflection seismic and Chirp data were also investigated for mapping and characterizing the geophysical hydrocarbon indicators such as BSR (bottom simulating reflector), blank zone, pock-mark etc. High organic carbon contents and sedimentation rates that suggest good condition for hydrocarbon generation. High pressure and low temperature condition, and high residual hydrocarbon concentrations are favor the formation of natural gas hydrate. In the piston cores, cracks generally oriented to bedding may indicate the gas expansion. The seismic data show several BSRs that are associated with natural gas hydrates and underlying free gas. A number of vertical to sub-vertical blank zones were well identified in the seismic sections. They often show the seismic pull-up structures, probably indicating the presence of high velocity hydrates. Numerous pockmarks were also observed in the Chirp profiles. They may indicate the presence of free gas below the hydrate stability zone as well.

• Journal of the Korean Society of Combustion
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• v.16 no.3
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• pp.41-51
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• 2011

In this paper, we describe the behavior of two self-excitations in laminar attached free-jet flames under the influence of DC electric fields, one of buoyancy-driven and the other of diffusion-thermal instability, established from the horizontal and vertical injection. In the horizontal injection with removed buoyancy effect, oscillating flames with the frequency of 1.3 - 7.4 Hz were observed in a certain condition with Lewis number more than unity. On the other hand, it was appeared Lewis number induced self-excitation as well as buoyancy-driven self-excitation in the vertical upward injection with DC electric fields. This behavior had frequency range of 1.6 - 9.4 Hz and was exhibited to attribute the buoyancy effect. Finally, a well-defined division about two self-excitations having similar frequency range is briefly discussed.

• Journal of the Korean earth science society
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• v.36 no.5
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• pp.437-446
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• 2015

Many edge detection methods, based on horizontal and vertical derivatives, have been introduced to provide us with intuitive information about the horizontal distribution of a subsurface anomalous body. Understanding the characteristics of each edge detection method is important for selecting an optimized method. In order to compare the characteristics of the individual methods, this study applied each method to synthetic magnetic data created using homogeneous prisms with different sizes, the numbers of bodies, and spacings between them. Seven edge detection methods were comprehensively and quantitatively analyzed: the total horizontal derivative (HD), the vertical derivative (VD), the 3D analytic signal (AS), the title derivative (TD), the theta map (TM), the horizontal derivative of tilt angle (HTD), and the normalized total horizontal derivative (NHD). HD and VD showed average good performance for a single-body model, but failed to detect multiple bodies. AS traced the edge for a single-body model comparatively well, but it was unable to detect an angulated corner and multiple bodies at the same time. TD and TM performed well in delineating the edges of shallower and larger bodies, but they showed relatively poor performance for deeper and smaller bodies. In contrast, they had a significant advantage in detecting the edges of multiple bodies. HTD showed poor performance in tracing close bodies since it was sensitive to an interference effect. NHD showed great performance under an appropriate window.

• Geomechanics and Engineering
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• v.10 no.5
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• pp.635-655
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• 2016

The effects of reinforcement on the horizontal and vertical deformations of geosynthetic reinforced retaining walls are investigated under a well-known seismic load (San Jose earthquake, 1955). Retaining walls are designed with internal and external stability (with appropriate factor of safety) and deformation is chosen as the main parameter for describing the wall behavior under seismic load. Retaining walls with various heights (6, 8, 10, 12 and 14 meter) are optimized for geosynthetics arrangement, and modeled with a finite element method. The stress-strain behavior of the walls under a well-known loading type, which has been used by many previous researchers, is investigated. A comparison is made between the reinforced and non-reinforced systems to evaluate the effect of reinforcement on decreasing the deformation of the retaining walls. The results show that the reinforcement system significantly controls the deformation of the top and middle of the retaining walls, which are the critical points under dynamic loading. It is shown that the optimized reinforcement system in retaining walls under the studied seismic loading could decrease horizontal and vertical deformation up to 90% and 40% respectively.

• Bulletin of the Korean Chemical Society
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• v.20 no.11
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• pp.1281-1287
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• 1999

The low-lying electronic states of diazirine and 3,3'-dimethyldiazirine have been studied by high level ab initio quantum chemical methods. The equilibrium geometries of the ground state and the first excited singlet and triplet states have been optimized using the Hartree-Fock (HF) and complete active space SCF (CASSCF) methods, as well as using the Møller-Plesset second order perturbation (MP2) theory and the single configuration interaction (CIS) theory. It was found that the first excited singlet state is of 1 B1 symmetry resulting from the n- π* transition, while the first excited triplet state is of 3 B2 symmetry resulting from the π- π* transition. The harmonic vibrational frequencies have been calculated at the optimized geometry of each electronic state, and the scaled frequencies have been compared with the experimental frequencies available. The adiabatic and vertical transition energies from the ground electronic state to the low-lying electronic states have been estimated by means of multireference methods based on the CASSCF wavefunctions, i.e., the multiconfigurational quasidegenerate second order perturbation (MCQDPT2) theory and the CASSCF second-order configuration interaction (CASSCF-SOCI) theory. The vertical transition energies have also been calculated by the CIS method for comparison. The computed transition energies, particularly by MCQDPT2, agree well with the experimental observations, and the electronic structures of the molecules have been discussed, particularly in light of the controversy over the existence of the so-called second electronic state.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.150-155
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• 2006

Falling liquid plays a role in a wide variety of naturally occurring phenomena as well as in the operation of industrial process equipment where heat and mass transfer take place. In such cases, it is required that the falling film should spread widely on the surface forming thin liquid film to enlarge contact surface. An addition of surface active agent to a falling liquid film affects the flow characteristics of the falling film. In this study the heat transfer characteristics for a falling liquid film has been investigated by an addition of the surface active agents. The falling liquid film was formed on a vertical flat plate. As the mass flow rate of liquid falling film is increased, the wetted area is a little increased while the heat transfer rate as well as heat transfer coefficient is significantly increased. It is also found that both wetted area and heat transfer rate is substantially increased while heat transfer coefficient is a little increased with an increase in the surfactant concentration at a given mass flow rate.

• Nuclear Engineering and Technology
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• v.41 no.9
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• pp.1135-1142
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• 2009

The activities related to this paper are to investigate the influence of nodalisation on simulating atmospheric stratification in the THAI experiment TH13 (ISP-47) with the German containment code COCOSYS. This article focuses on different nodalisations of the vessel dome, where an atmospheric stratification occurred due to a high helium content. The volume of the dome was divided into several levels that were varied horizontally into different geometries. These geometries differ in the number of zones as well as in the existence of zones that enable the direct rise of an ascending steam plume into the vessel dome. Additionally, the vertical subdivision of the vessel dome was increased to simulate density gradients in a more detailed way. It was pointed out that the proper simulation of atmospheric stratifications and their dissolution depends on both a suitable horizontal as well as vertical nodalisation scheme. Besides, the treatment of fog droplets has an influence if their settlement is not simulated correctly. This report gives an overview of the gained experience and provides nodalisation requirements to simulate atmospheric stratifications and their proper dissolution.