• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.12
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• pp.91-99
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• 1994

We used CMOS current mirror and differenial amplifier to find out how the degradation of each devices in circuit affect total circuit performance. The devices in circuit wer degraded by hot-carrier generated during circuit operation and total circuit performance were changed according to the change of each device parameters. To examine the circuit performance phenomena of current mirror, we analyzed three diffent kinds of current mirrors and made correlation model between circuit performance and stressed device parameters, and compare hot-carrier immunity of these circuits. Also we analyzed how the performance of differential amplifier degraded from the initial value after hot-carrier stress incircuit operations.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2573-2578
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• 2007

In order to investigate the vortex body frame interaction around the side mirror of a passenger car, velocity vector fields in the wake, pressure distributions and boundary layer flows over both the mirror surface and the mirror housing, have been measured by several experimental tools. It was resulted that only within an half downstream distance of the mirror span there appears the recirculation zone, and also found that vortex trail towards to the driver side window between A and B pillars, making the acoustic noise and vibration. Wake vortex rolls up after this recirculating zone and makes the trail of the vortex center towards the driver side window, which was also confirmed by measurements of wake velocity vectors in the vertical sections of the trail and visualization over the side mirror surfaces as well. It was also observed that total pressure distribution over the mirror surface has the minimum peak near the lower tip region which can be considered as the origin of the vortex center. It can be concluded that the geometrical modification of the lower tip and the upper root area of the mirror housing is the key to control the wake vortex.

• Design & Manufacturing
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• v.12 no.1
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• pp.36-40
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• 2018

The car requires an inside mirror installed between the driver's seat and the passenger's seat to ensure the driver's rear and side view of the driver. Inside mirrors must always be attached to the vehicle to ensure the driver's visibility. Inside mirrors attached to the windshield of a vehicle are always exposed to direct sunlight and should be semi-permanently usable in hot and humid summer weather in Korea. Therefore, the mirror mount, which is the junction of the inside mirror, is particularly important in corrosion resistance and wear resistance suitable for humidity. Mirror mounts are currently difficult to manufacture due to their reliance on powder molding technology in advanced countries such as Japan and Germany. This paper focuses on the fabrication of high corrosion resistant stainless mirror mounts by vacuum sintering technique and focuses on the selection of materials suitable for the production of mirror mounts through experiments of 300 series stainless steel and 400 series stainless steel manufactured by vacuum sintering.

• The Optical Journal
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• v.7 no.3 s.37
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• pp.64-67
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• 1995

• Journal of Energy Engineering
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• v.23 no.4
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• pp.56-60
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• 2014

Highly concentrated sunlight obtained from a solar concentrator mounted on a solar tracker can be divided into the infrared and visible region before it is actually applied. That is, solar rays are directed toward a unit optically separating sunlight into the infrared and visible region by a hot mirror as they impinge on the surface of a secondary reflector. The Infrared rays can be utilized for thermoacoustic applications while visible rays can be utilized for indoor lighting. This work introduces the separation of two different kinds of light; sunlight and artificial light. As for the artificial light, its wavelength extended from 400m to 720m for the visible region and 620m to 940m for the infrared region. Comparatively, a series of tests performed on sunlight revealed its separation in the visible region from 460m to 680m whereas from 620m to 940m for the artificial light.

• Journal of the Korean Society for Precision Engineering
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• v.34 no.3
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• pp.199-203
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• 2017

Hot embossing techniques are used to engrave patterns on plastic substrates. Roll based hot embossing uses a heated roll for a continuous process. A heated roll with relief patterns is impressed on a preheated plastic substrate. Then, the substrate is cooled down quickly to prevent thermal shrinkage. The roll speed is normally very slow to ensure substrate temperature increase up to the glass transition temperature. In this paper, we propose a noncontact preheating technique using focused infrared light. The infrared light is focused as a line beam on a plastic substrate using an elliptical mirror just before entering the hot embossing roll. The mid range infrared light efficiently raises the substrate temperature. For preliminary tests, substrate deformation and temperature changes were monitored according to substrate speed. The experiments show that the proposed technique is a good possibility for high speed hot embossing.

• Journal of the Korean Ceramic Society
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• v.24 no.4
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• pp.313-320
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• 1987

Fracture toughness of hot pressed cordierite-SiC whisker ceramic composites contained up to 40vol.% SiC whiskers were determined by using the indentation crack length(IC), indentation strengthin-bending(IS), and single-edge notched-beam(SENB) methods. The results were compared to stress intensity factor, KB, at the crack branching boundary measured by using the mirror zone radius (MZ) method. IS method seems to provide a more reasonable estimation of fracture toughness than other methods for these composites.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.110-111
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• 2008

Diamond material were manufactured using electrical pyrolysis method and hot filament method. Surface morphology was observed with SEM and its microstructure was investigated using Raman spectroscopy. The accumulation of the particles was observed to have strong selective and to deposit at the substrate only on the roughly polished steel surface compared to the mirror polished implying that the particle was a charged.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.1
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• pp.56-61
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• 1996

A hot wall epitaxy (HWE) apparatus with double source tubes was manufactured. This apparatus can be used to grow two kinds of epilayers at the same time or to grow heterostructures and multilayers. Undoped ZnSe single crystal films were grown on GaAs(100) substrates byusing this apparatus. SEM, XRD and PL analyses indicated that epilayers had good crystalline and optical quality. The epilayers grown at the source temperature 660 .deg. C and the substrates temperature $350^{\circ}C$. in $2 {\times} 10^{-6}$ toor were mirror like and good quality. PL measurements show that the crystalline qualityis comparable with that of the ZnSe/GaAs epilayer grown by molecular beam epitaxy.

• Korean Journal of Optics and Photonics
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• v.34 no.3
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• pp.106-116
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• 2023

In this paper, we designed a coaxial dual camera incorporating two optical systems-one for the visible rays and the other for far-infrared ones-with the aim of capturing images in both wavelength ranges. The far-infrared system, which uses an uncooled detector, has a sensor array of 640×480 pixels. The visible ray system has 1,945×1,097 pixels. The coaxial dual optical system was designed using a hot mirror beam splitter to minimize heat transfer caused by infrared rays in the visible ray optical system. The optimization process revealed that the final version of the dual camera system reached more than 90% of the fusion performance between two separate images from dual systems. Multiple rigorous testing processes confirmed that the coaxial dual camera we designed demonstrates meaningful design efficiency and improved image conformity degree compared to existing dual cameras.