• Proceedings of the Korean Vacuum Society Conference
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• 2002.06a
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• pp.183-184
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• 2002

• Transactions of Materials Processing
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• v.10 no.3
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• pp.214-222
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• 2001

The homogeneous distribution of solid region without liquid segregation is important in terms of high quality component during thixoforming process. In closed die semi-solid forging process, liquid segregation is strongly affected by injection velocity than solid fraction because the material has to travel relatively long distance to fill the cavity through a narrow gate. The designed die by computer simulation data was used to thixoforging process. The thixoforming velocity to prediction the liquid segregation had been determined with strain rate associated with multistage velocity control during compression test of semi-solid material. The optimal forging velocity and die temperature were investigated to produce the near-net-shape compressor component. The mechanical properties of thixoformed component were tested with various die and material temperatures before and after heat treatment.

• Bulletin of the Korean Chemical Society
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• v.23 no.12
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• pp.1729-1732
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• 2002

The LB71350,(3S, 4R)-Epoxy-(5S)-[[N-(1-methylethoxy)carbonyl]-3-(methylsulfonyl)-L-valinyl]amino]-N-[2-methyl-(1R)-[(phenyl)carbonylpropyl-6-phenylhexanamide, is a novel HIV protease inhibitor. Its equilibrium solubility at room temperature was less than $40{\mu}g/mL.$ It was speculated that the low aqueous solubility might be due to the high crystalline lattice energy resulting from intermolecular hydrogen bonds. The present study was carried out to learn the solid-state characteristics of LB71350 using analytical methods such as NMR, FT-IR and XRD. $^{13}C$ Solid-state NMR, solution NMR, and FT-IR spectra of the various solid forms of LB71350 were used to identify the conformation and structure of the solid forms. The chemical shifts of $^{13}C$ solid-state NMR spectra suggest that the crystalline form might have 3 intermolecular hydrogen bondings between monomers.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.05a
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• pp.147-150
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• 2003

The purpose of this research was to develope components of micro solid propellant thruster. Micro solid propellant thruster had four basic components: combustion chamber, nozzle, solid propellant and micro heater for ignition. A performance of micro heater and characteristic of solid propellant was investigated. Micro heater was fabricated by conventional MEMS process and Platinum layer was used for heating element. Effect of geometry parameters on micro heater was tested. The temperature responses of heater with respect to each parameters was compared for a given electrical power. The characteristic of solid propellant(HTPB/AP) was investigated to obtain burning velocity in small chamber. Additionally, a capacity of filling propellant with high viscosity in small chamber was checked to guarantee for the micro fabrication.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1280-1285
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• 2004

Microsystem technology has been applied to space technology and became one of the enabling technology by which low cost and high efficiency are achievable. Micro propulsion system is a key technology in the miniature satellite because micro satellite requires very small and precise thrust force for maneuvering and attitude control. In this paper research on micro solid propellant thruster is reported. Micro solid propellant thruster has four basic components; micro combustion chamber, micro nozzle, solid propellant and micro igniter. In this research igniter, solid propellant and combustion chamber are focused. Micro igniter was fabricated through typical micromachining and evaluated. The characteristic of solid propellant was investigated to observe burning characteristic and to obtain burning velocity. Change of thrust force and the amount of energy loss following scale down at micro combustion chamber were estimated by numerical simulation based on empirical data and through the calculation normalized specific impulses were compared to figure out the efficiency of combustion chamber.

• Transactions of the Society of Information Storage Systems
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• v.11 no.2
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• pp.22-25
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• 2015

In this paper, we demonstrate solid-immersion lens based confocal microscopy using super-continuum generation effect. Using super-continuum generation effect, we could diversify the excitation wavelength of confocal microscopy. Further, high refractive index of solid-immersion lens would increase the resolution of confocal microscopy. As a result, by applying the super-continuum generation effect and solid-immersion lens to confocal microscopy, some problems of confocal fluorescent microscopy, the excitation wavelength and the resolution, could be overcome. To verify it, we made home-built solid-immersion lens based confocal microscopy using super-continuum generation effect, and evaluate the performance of the system.

• Biomedical Science Letters
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• v.25 no.2
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• pp.170-176
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• 2019

The objective of this study was to evaluate the characteristics of the mixtures of choline alphoscerate (alpha-glycerylphosphorylcholine, alpha-GPC), in the liquid form, and sucrose ester, which formed a solid composite. The choline alphoscerate solid composites were prepared using different ratios of sucrose ester, and different preparation methods, such as air drying and rotary evaporation, were compared for their preparation efficacy. We examined the characteristics of the solid composites by using scanning electron microscopy (SEM), angle of repose, and moisture content. The ideal mixing ratio of choline alphoscerate and sucrose ester was determined as 1:3 and air drying was found to be more suitable for the preparation of solid composites than rotary evaporation. SEM measurements of the degree of dispersion and the size of particles indicated that a high-temperature air method was more suitable. These results demonstrated the successful preparation of choline alphoscerate solid composites that have potential for industrial use.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.307-308
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• 2019

The Pohang Light Source (PLS) - II is a 3 GeV third-generation synchrotron radiation facility. To inject electron beam from LINAC, a kicker modulator system and kicker magnets are installed in the PLS-II storage ring tunnel. The injected beam then falls into the storage ring beam dynamic aperture. This paper describes the design and implementation of the solid-state kicker modulator for PLS-II. The solid-state kicker modulator is consisted of high voltage solid state switch stacks. the technical considerations of the solid-state switch stacking for kicker modulator is discussed. The achieved capability of the solid-state kicker modulator demonstrates that is fulfills the design requirement of providing half-sine pulsed current of 10kA (peak), 6us (Base-width), with jitter < 2ns (Standard deviation). simulation and experimental results are presented to demonstrate the performance of the solid-state kicker modulator.

• Asian Journal of Innovation and Policy
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• v.12 no.3
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• pp.345-362
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• 2023

As the widespread adoption and proliferation of electric vehicles continue, the secondary battery market is experiencing rapid growth. However, lithium-ion batteries, which constitute a majority of secondary batteries, present high risks of fire and explosion. Solid-state batteries are thus garnering attention as the next-generation batteries since they eliminate fire hazards and significantly reduce the risk of explosions. Against this background, the study aimed to analyze research trends and provide insights by examining 2,927 domestic papers related to solid-state batteries over the past decade (2013-2022). Specifically, we used topic modeling to extract major keywords associated with solid-state batteries research and to explore the network characteristics across major topics. The changes in research on solid-state batteries were analyzed in-depth by calculating topic dominance by year. The findings provide an overview of the emerging trends in domestic solid-state battery research, and might serve as a valuable reference in shaping long-term research directions.

• KSTLE International Journal
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• v.2 no.2
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• pp.150-153
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• 2001

The effects of humidity on friction performance of automotive brake materials were studied using a pad-on-disk type friction tester. Three different friction materials based on a simple formulation were investigated by changing the solid lubricant graphite, MoS$_2$, and Sb$_2$S$_3$. Friction materials without solid lubricants were also examined to study the effect of other ingredients in the matrix on humidity. The friction material containing graphite was strongly affected by the humidity showing lower friction coefficient at high humidity level than other conditions. On the other hand, the friction material containing MoS$_2$exhibited higher friction coefficient at initial stage under high humidity level. The friction material without solid lubricant or with Sb$_2$S$_3$ was not affected by humidity conditions. However, the friction material containing barite showed strong speed dependence.