Sang Hwa Kim

Agency for Defense Development

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Co-Authors

Byung-Ha Kim

Korea Maritime and Ocean University

Yong-Gyoo Jin

Kyungil University

Min-Jea Tahk

Korea Advanced Institute of Science and Technology

Yun Ho Shin

Inha University

Liang‐Chy Chien

National Sun Yat-sen University

Dae Woong Lee

Gangneung–Wonju National University

Seung Hoon Ro

Kumoh National Institute of Technology

Hong-Seok Kim

Google (United States)

Seunghwan Kim

Korea Institute of Science and Technology

Eun Young Lim

Pusan National University

Cooperative Institutions

Kyungpook National University

Pusan National University

Kyung Hee University

Yonsei University

Government of the Republic of Korea

Korea Institute of Science and Technology

Korea Advanced Institute of Science and Technology

Pohang University of Science and Technology

Seoul National University

Asan Medical Center

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Research Field

Rhodium Catalyzed Reaction of Formybenzoyldiazomethane with Thiophene Derivatives

Journal of the Korean Chemical Society (1996)

Hong Seok Kim Sang Hwa Kim Dong Il Kim

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Citations (1)

Synthetic Studies on Discokiolide B

Journal of the Korean Chemical Society (1996)

Hong Seok Kim Sang Hwa Kim Ju Young Lee

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Synthesis of 2-Substituted-1,3-Oxazole-4-Carboxaldehyde via 1,3-Dipolar Cycloaddition.

Bulletin of the Korean Chemical Society (1993)

Hong-Seok Kim Sang Hwa Kim Hak Ki Lee

Oxazole

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A Study on the Rotation Accuracy According to Unbalance Variation of High Precision Spindle Unit for Machine Tool

Journal of the Korean Society of Manufacturing Process Engineers (2012)

Sang Hwa Kim Byung-Ha Kim Yong-Gyoo Jin

The spindle unit is a core part in high precision machine tool. Rotation accuracy of spindle unit is needed for high dignity cutting and improving the performance of machine tool. However, there are many factors to effect to rotational error motion(rotation accuracy). This study studied how rotational error motion is variation when unbalance amount is variation. Rotation accuracy of initial spindle unit is decided depending on parts and assembly such as bearing. When it is rotation, vibration and noise is appeared depending on volume of unbalance amount, so it works to decrease unbalance amount. The purpose of the study tests that unbalance amount how much effects to initial rotation condition. The result of the study shows that accuracy of parts and assembly is highly necessary to reach high rotation accuracy and unbalance amount hardly effects to initial rotation accuracy. However, it shorten spindle's life because vibration and noise is increasing by increasing unbalance amount and we can expect situation that rotation accuracy is falling by long time operation.

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Experimental study on integrated servo control for canard-controlled missiles [Correspondence]

IEEE Transactions on Aerospace and Electronic Systems (2016)

Sang Hwa Kim Min-Jea Tahk Ha-Jun Lee Seunghwan Kim

This paper describes an experimental study on an integrated servo control method. Conventional servo control schemes may experience performance degradation under the presence of physical constraints. An integrated scheme is proposed in this study to address this problem. In the proposed method, three controllers correspond to autopilot commands directly instead of four actuators. Various simulations and experiments show that the proposed integrated servo control method provides better performance than the conventional ones.

Servomechanism

Autopilot

10.1109/taes.2016.150211

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The Effect of Medical Service Quality Perceived by Medical Tourists on Customer Satisfaction: Focused on Daegu Metropolitan City

Kimdaegeun Sang Hwa Kim

Customer Satisfaction

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Design Alterations of a Hydraulic Press Machine for the Improved Stability

Journal of the Semiconductor & Display Technology (2019)

Yun Ho Shin Seung Hoon Ro Young Jo Kim Dae Woong Lee Sang Hwa Kim

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Effects of polymer concentration and localization on the electro-optical performance of cholesteric flexoelectro-optical devices

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE (2005)

Sang Hwa Kim Xiaoli Zhou L. Komitov Liang‐Chy Chien

We discussed the effect of polymer concentration and localization on flexoelectro-optical device using short pitch cholesterics oriented in uniform lying helix texture. By using a small concentration of photoreactive liquid crystal monomer with various concentrations and selecting the illumination conditions, we have been able to create a localized polymeric network at both substrate surfaces. We can stabilized the two switching modes and eliminating at the same time the effect of the residual birefringence of the polymeric network in the field-unwound state of the sample. The device has two operating modes: amplitude and phase modulation mode, respectively. The amplitude modulation mode is a fast in-plane switching of the device optic axis that enables to achieve a 100 % modulation of the transmitted light intensity whereas the phase mode gives a continuous change of the refractive index and thus of the phase shift of the transmitted light.

Modulation (music)

Contrast ratio

10.1117/12.584499

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Citations (4)

Polymer enhanced liquid crystal displays

Sang Hwa Kim L.-C. Chien

In the paper, we present fast switching devices by using polymer to enhance the electro-optical properties of existing bend nematic and ferroelectric cells. This method refers to the use of a small amount of polymer to modify or stabilize the orientation of liquid crystal at the field-induced states. In this presentation, we will report methods of using a phase-separated polymer network by liquid crystal templating to stabilize the bend state of a nematic cell and analog-switching ferroelectric devices. In addition, we will present the cell gap control of plastic LCDs.

Fast switching

Polymer network

10.1109/leos.2003.1253123

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Citations (2)

Liquid crystal blazed gratings formed in a single-step through photo-induced localization of polymer into a prismatic structure

Optics Express (2004)

Sang Hwa Kim Liang‐Chy Chien

A liquid crystal blazed grating having a prismatic polymer microstructure has been developed. The polymer structure is fabricated by photo-induced localization and polymerization of a small concentration of monomer onto one substrate of an electro-optical cell by using ultraviolet light irradiation at the direction 45 degrees from normal incident. Using this method a periodical one-dimensional pattern with a prismatic shape of polymer can be formed on a one-dimensional pattern-forming state of a cholesteric host. The optical diffraction properties of the grating are evaluated by the application of electric field and light incident angles.

Diffraction efficiency

Ultraviolet light

Ray

10.1364/opex.12.001238

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Citations (9)