• 한국정보디스플레이학회:학술대회논문집
• /
• 2005.07a
• /
• pp.137-140
• /
• 2005

Organic light emitting transistors (OLET) which are vertically combined with the organic static induction transistor (OSIT) and organic light emitting diode (OLED) are fabricated and the device characteristics are investigated. High luminance modulations by relatively low gate voltages are obtained. In order to realize the flexible electronic circuits and displays, we have fabricated OSIT on plastic substrates. The OSIT fabricated on plastic substrate show almost same characteristics comparing with those of nonflexible OSIT on glass substrate. The OLET described here is a suitable element for flexible sheet displays.

• Journal of the Korean Electrochemical Society
• /
• v.17 no.3
• /
• pp.139-148
• /
• 2014

Electrochemical energy-storage devices such as batteries and supercapacitors are important components in emerging portable electronic device, electric vehicle, and clean energy storage and supply technologies. This review describes recent progress in the development of nanostructured electrodes, the main component of the electrochemical energy-storage device, prepared by layer-by-layer (LbL) electrostatic assembly. Major advantages associated with, and challenges to, the fabrication of LbL electrodes, as well as the future outlook for expanding the application of LbL techniques, are discussed.

• Journal of the Semiconductor & Display Technology
• /
• v.5 no.4 s.17
• /
• pp.29-34
• /
• 2006

In order to design an OLED(Organic Luminescent Emitting Device) evaporation system, geometric simulation of film thickness distribution profile is required. For the OLED evaporation process, thin film thickness uniformity is of great practical importance. In this paper, a geometric modeling algorithm is introduced for process simulation of the OLED evaporating process. The physical fact of the evaporating process is modeled mathematically. Based on the developed method, the thickness of the thin-film layer can be successfully controlled.

• Proceedings of the KSME Conference
• /
• 2001.06b
• /
• pp.65-69
• /
• 2001

In this study, the deformation of the free surface motion of a magnetic fluid for the change in electromagnetic force is discussed. In case, magnetic fluid in characteristics of fluid adjusted to the opposite direction of the gravity direction. Thus, the device of a magnetic fluid proposed the complete zero-leakage Sealing and the surface actuator. The device of surface deformation as well comparison between numerical simulation and experiments as will be presented.

• Journal of Industrial Technology
• /
• v.30 no.A
• /
• pp.89-93
• /
• 2010

This research suggested a development of a Data Acquisition System for strain gauge sensor which enables the usage of portable device in the various engineering field that includes, a strain indicator which is frequently used in civil and mechanical engineering, and a GUI function of data acquisition device. The developed system can record 16 channels of strain gauges at a time and its resolution is over 16 bits which can be used effectively in the actual field.

• Journal of Korean Neurosurgical Society
• /
• v.43 no.1
• /
• pp.26-30
• /
• 2008

Objective : The authors developed a stereotactic device for irradiation of small animals with Leksell Gamma Knife Model C. Development and verification procedures were described in this article. Methods : The device was designed to satisfy three requirements. The mechanical accuracy in positioning was to be managed within 0.5 mm. The strength of the device and structure were to be compromised to provide enough strength to hold a small animal during irradiation and to interfere the gamma ray beam as little as possible. The device was to be used in combination with the Leksell G-$frame^{(R)}$ and $KOPF^{(R)}$ rat adaptor. The irradiation point was determined by separate imaging sequences such as plain X-ray images. Results : The absolute dose rate with the device in a Leksell Gamma Knife was 3.7% less than the value calculated from Leksell Gamma $Plan^{(R)}$. The dose distributions measured with $GAFCHROMIC^{(R)}$ MD-55 film corresponded to those of Leksell Gamma $Plan^{(R)}$ within acceptable range. The device was used in a series of rat experiments with a 4 mm helmet of Leksell Gamma Knife. Conclusion : A stereotactic device for irradiation of small animals with Leksell Gamma Knife Model C has been developed so that it fulfilled above requirements. Absorbed dose and dose distribution at the center of a Gamma Knife helmet are in acceptable ranges. The device provides enough accuracy for stereotactic irradiation with acceptable practicality.

• Journal of the Microelectronics and Packaging Society
• /
• v.25 no.2
• /
• pp.1-8
• /
• 2018

In the soldering industry, a variety of lead-free solders have been developed as a part of restricting lead in electronic packaging. Sn-Ag-Cu (SAC) lead-free solder is regarded as one of the most superior candidates, owing to its low melting point and high solderability as well as the mechanical property. On the other hand, the mechanical property of SAC solder is directly influenced by intermetallic compounds (IMCs) in the solder joint. Although IMCs in SAC solder play an important role in bonding solder joints and impart strength to the surrounding solder matrix, a large amount of IMCs may cause poor strength, due to their brittle nature. In other words, the mechanical properties of SAC solder are of some concern because of the formation of large and brittle IMCs. As the IMCs grow, they may cause poor device performance, resulting in the failure of the electronic device. Therefore, new solder technologies which can control the IMC growth are necessary to address these issues satisfactorily. There are an advanced nanotechnology for microstructural refinement that lead to improve mechanical properties of solder alloys with nanoparticle additions, which are defined as nano-reinforced solders. These nano-reinforced solders increase the mechanical strength of the solder due to the dispersion hardening as well as solderability of the solder. This paper introduces the nano-reinforced solders, including its principles, types, and various properties.

• Progress in Superconductivity and Cryogenics
• /
• v.19 no.4
• /
• pp.45-50
• /
• 2017

This paper presents a conceptual design and analysis for a 1-kW-class high-temperature superconducting rotating machine (HTSRM) rotor. The designed prototype is a small-scale integration system of a HTSRM and a HTS contactless rotary excitation device (CRED). Technically, CRED and HTSRM are connected in the same shaft, and it effectively charges the HTS coils of the rotor field winding by pumping fluxes via a non-contact method. HTS coils in rotor pole body and toroidal HTS wire in CRED rotor are cooled and operated by liquid nitrogen in cryogen tank located in inner-most of rotor. Therefore, it is crucial to securely maintain the thermal stability of cryogenic environment inside rotor. Especially, we critically consider not only on mechanical characteristics of the rotor but also on cryogenic thermal characteristics. In this paper, we conduct two main tasks covering optimizing a conceptual design and performing operational characteristics. First, rotor parameters are conceptually designed by analytical design codes. These parameters consider to mechanical and thermal performances such as mechanical strength, mechanical rigidity, and thermal heat losses of the rotor. Second, mechanical and thermal characteristics of rotor for 1-kW-class HTSRM are analyzed to verify the feasible operation conditions. Hence, three-dimensional finite element analysis (3D-FEA) method is used to perform these analyses in ANSYS-Workbench platform.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.26 no.1
• /
• pp.130-136
• /
• 2017

The three-wheel pitching machine is a device that throws balls automatically instead of a pitcher and is used chiefly to train baseball players. The machine is abundantly used by people in indoor baseball grounds for baseball games. However, in Korea, foreign products are more popular because the efficiency of domestic products is poor as compared to that of the foreign ones. Therefore, a miniature pitching machine was manufactured to analyze and solve the problems of the existing machine. We added a feeder device to insert the balls in the machine and developed a smart phone application. The machine is easily controlled by a smart phone with bluetooth. While manufacturing the miniature, the existing problems were mitigated and the machine was redesigned for mass production. This study attempted to render the pitching machine more convenient and safer as a substitute for foreign pitching machines.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.24 no.2
• /
• pp.1-13
• /
• 2020

The characterization of aging of the pyrotechnic device is conducted thermally, chemically, and spectroscopically. The device is comprised of two parts: (i) igniter composed of Zr and (ii) pyrotechnic delay composed of ZrNi alloy. The thermally induced chemical reaction is identified through Differential Scanning Calorimetry (DSC) and Thermogravimetry Analysis (TGA). The peak deconvolution of the themo-chemical data is used to estimate the enthalpy change of each metallic fuel component. Laser Induced Breakdown Spectroscopy (LIBS) and X-ray Photoelectron Spectroscopy (XPS) are used for chemical species analysis. The decomposition of oxidants by moisture significantly affected the fuel aging, and the formation of oxide film and metal oxide on the fuel surface gave rise to the thermal energy decrease.