• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1703-1708
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• 2003

The present study investigates the effect of injection angle of water mist on fire suppression characteristics by numerical simulation. In order to validate the temperature field by numerical simulation, the predicted results are compared with experimental data. It shows that the temperature difference between measurements and predictions are within $10^{\circ}C$ Numerical simulations of fire suppression are performed for 4 different injection angle($60^{\circ}$, $90^{\circ}$, $120^{\circ}$, and $180^{\circ}$). The grobal mean temperature over the fire compartment decrease with increasing of spray angle. The result shows that the heat transfer between droplets and gas phase are enhaced with the increasing of spray angle. Near the fire source, temperature field by the wide spray angle is slightly higher than that of narrow injection angle because of direct cooling of fire source.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.189-192
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• 2002

In this paper, the submarine model, called DARPA SUBOFF model, has been numerically analyzed to investigate the aerodynamic forces variation in terms of angle of attacks and yaw angles. The SUBOFF model is consisted of the three parts : axisymmetric body, fairwater, and four symmetric stern appendages. Three dimensional unsteady incompressible Wavier-Stokes equation was used on curvilinear multi-block grid system. To validate the present code, the SUBOFF tare hull and an ellipsoid at angle of attacks of $10^{\circ}\;and\;30^{\circ}$ were simulated and a good agreement with experiments was obtained. After the code validation, the flows over SUBOFF model were simulated at three different angle of attacks and yaw angles. The variation of aerodynamic forces in terms of angle of attack and yaw angle were calculated. Also, to understand the flow features around a submarine with variation of yaw and attack angle, the pressure contours and streamlines were plotted.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.2
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• pp.48-55
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• 2010

We have development the steering angle sensor using not only detecting parts but also integrating technique with semiconductors for automobile applications. The performance design and analysis of the steering angle sensor for intelligent vehicles is complicated due to variety of parameters. In this study, the performance characteristics of the angle sensor were analyzed using test rig. By means of magnetic induction technique, these new the steering angle sensors showed excellent magnetic characteristics. The detection range of steering angle sensor obtained was ${\pm}800^{\circ}$, the maximum non-linearity is 0.744% Full Span and the temperature range was $-40^{\circ}C{\sim}+125^{\circ}C$. With this conclusive, the inductive angle sensor was quite satisfactory for many applications in intelligent vehicles.

• International Journal of Aeronautical and Space Sciences
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• v.14 no.4
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• pp.379-386
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• 2013

The hemispherical resonator gyroscope is a type of vibratory gyroscope, which can measure angle or angular rate, based on its operating mode. This paper deals with the case when the hemispherical resonator gyroscope is operated in angle measurement mode. In angle measurement mode, the resonator pattern angle precesses, with respect to the external rotation input, by the principle of the Coriolis effect, so that the external rotation can be estimated, by measuring the amount of precession angle. However, this pattern angle drifts, due to the manufacturing error of the resonator. Since the drift effect causes degradation of the angle estimation performance of the resonator, the corresponding drift compensation control should be performed, to enhance the estimation performance. In this paper, a mathematical model of the hemispherical resonator gyro is first introduced. By using the mathematical model, a nonlinear observer for imperfection parameter estimation, and the corresponding compensation controller are designed to operate hemispherical resonator gyros, as angle measurement sensors.

• The korean journal of orthodontics
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• v.15 no.2
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• pp.279-289
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• 1985

This study was undertaken to find out the factor highly correlated to the depth of overbite among the skeletal factors of the craniofacial complex using lateral roentgenocephalograms. The subjects cconsited of fifty normal occlusions, sixty Class I malocclusions, sixty Class II division I malocclustions and sixty Class III malocclusions. The results were as follows: 1. Ans-Go-Me angle and lower genial angle showed high correlation to the depth of overbite in the total malocclusion sample. 2. The mean values of Ans-Go-Me angle and lower goinal angle for the normal sample were $49.8^{\circ}\;and\;75.6^{\circ}$, respectively. 3. Ans-Go-Me angle above $56^{\circ}$ or lower gonial angle above $84^{\circ}$ indicated a tendency toward an openbite. Conversely, Ans-Go-Me angle below $48^{\circ}$ or lower goinal angle below $73^{\circ}$ indicated a tendency toward a deepbite.

• Journal of the Korean Society of Safety
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• v.18 no.2
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• pp.28-33
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• 2003

The present study investigates the effect of injection angle of water mist on fire suppression characteristics by numerical simulation. In order to validate the temperature field by numerical simulation, the predicted results are compared with experimental data. It shows that the temperature difference between measurements and predictions are within $10^{\circ}C$. Numerical simulations of fire suppression are performed for 4 different injection angle($60^{\circ}$, $90^{\circ}$, $^120{\circ}$, and $180^{\circ}$). The global mean temperature over the fire compartment decrease with increasing of spray angle. The result shows that the heat transfer between droplets and gas phase are enhanced with the increasing of spray angle. Near the fire source, temperature field by the wide spray angle is slightly higher than that of narrow injection angle because of direct cooling of fire source.

• Journal of the Korean Society of Clothing and Textiles
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• v.27 no.5
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• pp.554-559
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• 2003

A newly developed contact angle measurement instrument by laser beam projection allows for rapid and direct determination of contact angles. The instrument may have a possibility to characterize newly developed nano-fibers. When the laser beam impinges on an edge of an interface of liquid and solid, projected beam were split across and made two straight lines on a tangent screen. From the result, it could measure the contact angle directly by reading the angle between two split beams. The purpose of this study was to prove reliability and reproducibility of the contact angle measurement instrument by laser beam projection compare to the conventional one by microscope through the comparative experiment and questionnaire. Test samples were selected by consideration of hydrophilic and hydrophobic, such as nylon 6 and polypropylene, respectively. The laser contact angle measurement has accurate, fast and convenient method to measure contact angle, and it can be a unique method to characterize nano-fibers.

• The Mathematical Education
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• v.51 no.4
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• pp.471-484
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• 2012

It is not easy to find the auxiliary line to solve the problem in connection with the circle, where it is the problem finding the central angle or angle at the circumference in a circle. The purpose of the study is to give an aid for this difficulties. The angle at the circumference is closely related to the arc. And so we looked into the problem in connection with the angle at the circumference in point of view of the arc. We have got the following the results. It is not necessary to draw the auxiliary line when solving the problem in connection with the angle at the circumference in point of view of the arc. And we can find the reason to draw the specific auxiliary in point of view of the arc. We hope that the results of research are given aids to a lot of students.

• Transactions of the Society of Information Storage Systems
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• v.7 no.1
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• pp.1-6
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• 2011

A control method for the angle servo of reference beam during reading recoded data images of a holographic data storage system is presented. The recording scheme with angle offset is adopted in order to verify the proposed angle servo. Using this recording scheme, the angle error signal is generated and we can implement the angle servo. Experiments have been performed on recording and reading data images to compensate Bragg angle mismatch.

• Archives of Metallurgy and Materials
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• v.66 no.4
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• pp.971-975
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• 2021

This study investigates the effects of grain boundary structures on mechanical properties of nanocrystalline Al-0.7Mg-1.0Cu alloy using nanoindentation system. Grain boundary structure transforms to high angle grain boundaries from low angle ones with increase of heat treatment temperature and the transformation temperature is about 400℃. Young's modulus and hardness are higher in sample with low angle grain boundaries, while creep length is larger in sample with high angle ones. These results indicate that progress of plastic deformation at room temperature is more difficult in sample with low angle ones. During compression test at 200℃, strain softening occurs in all samples. However, yield strength in sample with low angle grain boundaries is higher twice than that with high angle ones due to higher activation energy for grain boundary sliding.