• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.597-602
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• 2020

The study was conducted to improve the efficiency of the test and to reduce the exposure dose of patients and operators by analyzing the difference in the moving speed of Lipiodol according to the temperature during lymphography. The device for injecting Lipiodol at a constant pressure was self-made, and after inserting Lipiodol into the Connecting Tube, the moving speed of the contrast agent was photographed at temperatures of 26℃, 36℃, and 46℃ using a heat transfer device. Lipiodol movement time from the Support Catheter to 20cm was measured and analyzed, and statistical significance was confirmed. In the 46℃ environment, the average moving time was 11 seconds, at 36℃ the average was 13 seconds, and at 26℃ the average was 17 seconds. Lipiodol showed a significant difference in moving time with increasing temperature (p<.001), and it was confirmed that the higher the temperature, the faster the moving speed. In the case of lymphangiography, when heated to a certain temperature (46 degrees) rather than injecting Lipiodol at room temperature, the injection speed can be increased and the speed of movement in the lymphatic vessel can be improved.

• Korean Journal of Optics and Photonics
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• v.16 no.3
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• pp.254-260
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• 2005

By incorporating large core polymer waveguides, which have been developed for increased alignment tolerance in passive fiber attachment, highly efficient variable optical attenuators are proposed. In order to find optimum device structures, 3-dimensional beam propagation method (BPM) simulations are performed. Heat distribution over the polymer film is calculated to find the 3-dimensional index profile data for the BPM simulation. Due to the small index contrast between the core and cladding materials in the large core waveguide, heat-induced radiation occurs for small heating power. While the ordinary VOA needs the temperature to change over $150^{\circ}C$ for 20 dB attenuation, the large core VOA requires only $70^{\circ}C$. In addition to the merit of passive fiber attachment, the proposed VOA has enhanced attenuation efficiency for the lower temperature change.

• Journal of the Optical Society of Korea
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• v.13 no.1
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• pp.65-74
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• 2009

Device quality indium tin oxide (ITO) films are deposited on glass substrates and ultra-thin diamond-like carbon films are deposited as a buffer layer on ITO by a pulsed Nd:YAG laser at 355 nm and 532 nm wavelength. ITO films deposited at room temperature are largely amorphous although their optical transmittances in the visible range are > 90%. The resistivity of their amorphous ITO films is too high to enable an efficient organic light-emitting device (OLED), in contrast to that deposited by a KrF laser. Substrate heating at $200^{\circ}C$ with laser wavelength of 355 nm, the ITO film resistivity decreases by almost an order of magnitude to $2{\times}10^{-4}\;{\Omega}\;cm$ while its optical transmittance is maintained at > 90%. The thermally induced crystallization of ITO has a preferred <111> directional orientation texture which largely accounts for the lowering of film resistivity. The background gas and deposition distance, that between the ITO target and the glass substrate, influence the thin-film microstructures. The optical and electrical properties are compared to published results using other nanosecond lasers and other fluence, as well as the use of ultra fast lasers. Molecularly doped, single-layer OLEDs of ITO/(PVK+TPD+$Alq_3$)/Al which are fabricated using pulsed-laser deposited ITO samples are compared to those fabricated using the commercial ITO. Effects such as surface texture and roughness of ITO and the insertion of DLC as a buffer layer into ITO/DLC/(PVK+TPD+$Alq_3$)/Al devices are investigated. The effects of DLC-on-ITO on OLED improvement such as better turn-on voltage and brightness are explained by a possible reduction of energy barrier to the hole injection from ITO into the light-emitting layer.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.8
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• pp.996-1003
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• 2019

The undergrounding of diverse ground facilities has led to a decrease in issues, such as foul smell of water supply systems and wastewater, a fall of telephone poles, electromagnetic waves and breaking of wires caused by a railway work. On the other hand, there are new issues, including a fall accident, explosion affected by flammable gas, a choking accident by harmful gas and a lack of oxygen concentration, a fire coming from high-tension wire heating and flooding in the manhole. Besides, these issues damage the civil society and are an anxiety to public safety. Therefore, this paper is focused on a smart manhole device for stable communication environments inside and outside the manhole and wireless communication with various devices for managing facilities in the manhole, and aims to make a contribution to public safety by suggesting a direction of future underground facility management.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.4
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• pp.641-648
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• 2023

Recently, the rapid growth of artificial intelligence among the 4th industrial revolution has progressed based on the performance improvement of semiconductor, and circuit integration. According to transistors, which help operation of internal electronic devices and equipment that have been progressed to be more complicated and miniaturized, the control of heat generation and improvement of heat dissipation efficiency have emerged as new performance indicators. The DUT(Device Under Test) Shell is equipment which detects malfunction transistor by evaluating the durability of transistor through heat dissipation in a state where the power is cut off at an arbitrary heating point applying the rating current to inspect the transistor. Since the DUT shell can test more transistor at the same time according to the heat dissipation structure inside the equipment, the heat dissipation efficiency has a direct relationship with the malfunction transistor detection efficiency. Thus, in this paper, we propose various method for PCB configuration structure to optimize heat dissipation of DUT shell and we also propose various transformation and thermal analysis of optimal DUT shell using computational fluid dynamics.

• The Journal of Korean Medicine
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• v.43 no.3
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• pp.150-163
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• 2022

Objectives: This research aimed to develop a guideline for evaluating safety and performance of electronic warm-acupuncture apparatus. With the development of medical devices like electronic warm-acupuncture apparatus with improved performance, convenience and safety measures compared to traditional warm-acupuncture needling, safety and performance guideline is a necessity. Methods: By referring to existing standards and guidelines of other electronic devices for Korean medicine with heating function, guideline for safety and performance assessment of electronic warm-acupuncture apparatus was drafted Results: The guideline, presents explanation for adequate temperature and settings of the apparatus, and safety measurements providing against thermal runaway situations along with guidelines for the manual. Guideline for detailed test method for the performance of the apparatus such as accuracy of temperature increase and the timer, and safety unit was also provided. The test items and suggested test methods for the requirements of biological, electrical and electromagnetic safety were referred to Korean approval documents of ministry of Food and Drug Safety. Conclusion: We proposed the relevant items to verify performance and safety of warm-acupuncture apparatus to assure patient safety and improve the quality of currently developing devices for application in clinical field.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2609-2614
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• 2007

Shell & Tube type Oil Cooler is widely used for hydraulic presses, die casting machines, generation equipments, machine tools and construction heavy machinery. Temperature of oil in the hydraulic system changes viscosity and thickness of oil film. They have a bad effect to performance and lubrication of hydraulic machinery, so it is important to know exactly the heat exchanging efficiency of oil cooler for controlling oil temperature. But most Korean manufacturers do not have test equipment for oil cooler, so they cannot carry out the efficiency test of oil cooler and it is impossible to verify its performance. This paper includes information of construction of necessary utilities for oil cooler test and design and manufacture of test equipment. One can select the optimum product by obtaining performance data through tests of various kinds of oil coolers. And also the paper developed a program which can be easily used for design of 2D and 3D drawings of oil cooler.

• Proceedings of the KIEE Conference
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• 2001.11a
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• pp.59-61
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• 2001

Electrostatically actuated test devices were designed to evaluate the elastic modulus of single crystalline Si (100) materials for MEMS device. Elastic modolus was calculated from resonant frequency by applying Rayleigh's energy method. Temperature effect on elastic properties was evaluated by detecting the resonant frequency change with increasing temperature to $600^{\circ}C$. The elastic modulus was decreased with heating and then increased with cooling, but specimen with thermal cycle showed a permanent change which is lower than the initial value. This phenomenon was explained by the change of interatomic force and the formation of $SiO_2$ layer on Si. The thickness of oxide layer was estimated by considering the change of mass and stiffness, and the formation of oxide layer was observed by the SEM photograph.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.5
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• pp.634-641
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• 2013

Condensing species behaviour downstream of a combustor was discussed with particle size distribution in this study. The effects of operating conditions in a biomass combustion facility, i.e. concentration of condensing species, temperature gradient, residence time and injection of adsorbents, on particle size distribution were investigated. Pyroligneous liquid which was completely vaporized at the temperature higher than $350^{\circ}C$ was used as a representative of condensing gaseous species. We found that particle size downstream of a combustor increased with increasing heating temperature (i.e. concentration of condensing species) and residence time. However, temperature gradient was not an important factor to control the particle size. The addition of $SiO_2$ precursor as an adsorbent could effectively prevent the particle formation by adsorbing condensing gaseous species on $SiO_2$ particles, and increased the particle size up to 300 nm, resulting in increasing particle removal efficiency in a conventional air pollution control device.

• International Journal of Aerospace System Engineering
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• v.1 no.1
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• pp.34-43
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• 2014

The STEP Cube Lab (Cube Laboratory for Space Technology Experimental Projects) is a 1U cube satellite developed by the Space Technology Synthesis Laboratory of Chosun University to be launched in 2015. Its mission objective is twofold: to determine which of the fundamental space technologies researched at domestic universities, will be potential candidates for use in future space missions and to verify the effectiveness of the technologies by investigating mission data obtained from on-orbit operation of the cube satellite. In this paper, a structural design concept based on the 1U standard to achieve the mission objective is introduced. The validity of the design has been demonstrated by quasi-static analysis and modal analysis. In addition, a non-explosive separation device triggered by burn wire heating, which is one of the main mission payloads is introduced.