• The Research Journal of the Costume Culture
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• v.31 no.5
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• pp.692-704
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• 2023

This study analyzed 214 sports knee braces found on Chinese websites between October 2022 and November 2022 to assess product type (impact protection material, fastening method, and protection method), material composition, size, weight, and main characteristics. The product type was further categorized according to (1) use of hard guard and soft guard protection method; (2) cover type, strap type, and slip-on type fastening method; and (3) pressure type and support type protection method. It also noted the physical shock protection materials used, including foam (EVA or polyurethane) attached to joints as a buffer material and plastic (TPU or PP) that protects the user's knee from external impacts. The study found that the materials that primarily comprise sports knee braces are a combination of nylon, polyester, and neoprene. Additionally, it found that most sports knee braces available on the market are available in three sizes based on knee circumference: M (35-38cm), L (38-41cm), and XL (41-44cm), while some products are available in one size only. Furthermore, the majority of the 214 products studied weighed 200g, followed by 1,000g. Finally, in terms of product characteristics, many sports knee braces utilize ring-shaped silicone pads to distribute the load pressure on the knees or incorporate sturdy adhesive velcro to improve knee stability.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.7
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• pp.1281-1286
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• 2006

We have used the silicon-carbide(4H-SiC) instead of conventional silicon materials to develope of the planar junction barrier schottky rectifier for ultra high breakdown voltage(1,200 V grade). The substrate size is 2 inch wafer, Its concentration is $3*10^{18}/cm^{3}$ of $n^{+}-$type, thickness of epitaxial layer $12{\mu}m$ conentration is $5*10^{15}cm^{-3}$ of n-type. The fabticated devices are junction barrier schottky rectifier, The guard ring for improvement of breakdown voltage is designed by the box-like impurity of boron, the width and space of guard ring was designed by variation. The contact metals to rectify were used by the $Ni(3,000\:{\AA})/Au(2,000\:{\AA})$. As a results, the on-state voltage is 1.26 V, on-state resistance is $45m{\Omega}/cm^{3}$, maximum value of improved reverse breakdown voltage is 1180V, reverse leakage current density is $2.26*10^{-5}A/CM^{3}$. We had improved the measureme nt results of the electrical parameters.

• Bulletin of the Korean Mathematical Society
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• v.54 no.2
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• pp.679-686
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• 2017

The present paper is devoted to self-adjoint cyclically compact operators on Hilbert-Kaplansky module over a ring of bounded measurable functions. The spectral theorem for such a class of operators is given. We use more simple and constructive method, which allowed to apply this result to compact operators relative to von Neumann algebras. Namely, a general form of compact operators relative to a type I von Neumann algebra is given.

• Polymer(Korea)
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• v.35 no.2
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• pp.136-140
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• 2011

The plasma resistances of nitrile curable perfluoro elastomer (NT PFE) and peroxide curable PFE (PO PFE) after exposing to $NF_3$ and $O_2$ remote plasmas were investigated by analyzing weight loss and morphology of O-ring made of PFE. The compounds were designed following the typical formulations of O-ring/seal which were applied in semiconductor and LCD production site. They were blended by an open roll mill, and then, O-ring was finally made by hot press molding and oven curing. The weight loss was calculated and morphology was observed for each atmosphere and temperature by a digital weighing machine and SEM. As results, it was confirmed the weight loss and related morphology were meaningfully different according to the cure type of PFE, filler system, and the species of remote plasma.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.655-659
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• 2006

This paper presents a novel electrostatic drop-on-demand inkjet device featured by a MEMS fabricated pole-type and hole-type nozzle with tube shaped orifice and investigates the feasibility of applying the inkjet device to display fabrication process. The electric voltage signal applied to the ring shaped upper electrode plate, against the hole-shaped ground or pole-shaped ground, referred here pole-type and hole-type nozzle respectively, allows ejection of small droplet to take place: That is, a tiny droplet is taken away from the peak of the mountain shaped liquid meniscus formed at the nozzle orifice. It is verified experimentally that the use of the pole type nozzle allows a stable and sustainable micro-dripping mode of droplet ejection for a wider range of applied voltages and of liquid viscosities. This demonstrates a feasibility of electrostatic drop-on-demand inkjet device as a disruptive alternative to conventional print heads such as thermal bubble or piezoelectric inkjet heads.

• Journal of The Korean Astronomical Society
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• v.17 no.1
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• pp.23-36
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• 1984

From the PDS scanning, isophote maps and surface luminosity distributions for the late type spiral galaxy NGC 6946 were obtained. Surface luminosity distribution showed that this galaxy can be classified as the Freeman's type II, and the deep spheroidal component was caused as a result of the ring structure in the central part of NGC 6946. Physical parameters-total magnitude ($M_T^B$), effective radius ($R_e^*$), central surface magnitude $U(0)_{CD}$, length scale (${\alpha}^{-1}$), disk-to-bulge ratio (D/B) and mass-to-luminosity ratio (M/L)-were also calculated, and the results show that NGC 6946 belongs to Sc I type galaxy according to the DDO classification, and is to be a fair sample of classification statge T=6.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.800-805
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• 2001

Both analytical and experimental studies are presented to investigate the strength of the membrane which is designed by Kogas and will be used as a sealing for a LNG tank. Kogas has already developed the Ring-Knot type membrane, but new type had yet to be developed. This paper reports on the results of investigations into this new type of membrane. Various theorical analyses using FEM and experiments are conducted on the basis of RPIS, and it is found that the RPIS is fully satisfied.

• Tribology and Lubricants
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• v.22 no.6
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• pp.314-319
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• 2006

In this paper, the friction and wear characteristics of contact type sealing unit far a water turbine have been presented. The sealing unit for a small hydropower generation is to stop a leakage of circulating water from an outside of an impeller to an inside of a rolling bearing. The friction heating between a seal ring and a seal seat may radically increase a surface temperature in which increase a power loss and wear on the rubbing surface. The surface wear strongly affect to the seal life of a mechanical face seal. In this study, the hardness of a stainless steel in which is a heat-treated is 892.8 in Victors hardness and the hardness of silicone carbide of SiC is 714.1 in Victors hardness. The surface hardness of a heat-treated stainless steel is 25% high compared with that of a ceramic material of SiC. The contact modes of rubbing surfaces are a dry friction, a water film friction and a mixed friction that is contaminated by a dust, silt, and moistures, etc. These two factors of a contact rubbing modes and a material property are very important parameters on the tribological performance such as a friction and wear between a seal ring and a seal seat in primary sealing unit. The experimental result shows that the surface hardness of a seal material is very important on the friction coefficient and a wear volume. Thus, the results recommend higher hardness of a seal material, which may reduce a friction loss and increase a wear life of primary seal components.

• Applied Chemistry for Engineering
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• v.9 no.3
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• pp.404-406
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• 1998

Analysis for the imidazoline type cationic surfactants was performed by the gas chromatography(GC) and high performance liquid chromatography(HPLC). The composition of the alkyl chain distribution was investigated by GC after base/Acid hydrolysis of the imidazoline ring. The distribution of total alkyl chain was separated clearly by a Bondclone C18/NOVA-Pak C18 HPLC column using 50% acetonitrile in methanol containing 0.1M sodium perchlorate as a mobile phase. Alkyl chain distribution and average molecular weight of imidazoline type cationic surfactants were obtained based on these analytical methods. The agreement of results from GC and HPLC was good. The detection limit of imidazoline by HPLC method was 10ng without pretreatment.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.5
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• pp.279-286
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• 2021

In this study, we investigated the behavior characteristics of the L-type flange bolt connection, which is used to connect upper and lower flanges having L-type ring sections, by bolts. This connection is mainly used in domestic wind turbine structures, wherein it is a vital component as any imperfection could cause the collapse of the entire structural system. Therefore, understanding the behavior characteristics of the L-type flange bolt connection is imperative. In this study, the connection's response to external force was simulated using finite element (FE) analysis and the FE model was idealized to behave as a single L-type bolt flange. The variation in the bolt tension and the L-type flange stress were analyzed to understand the behavior characteristics of the connection. Moreover, the bolt-load function models proposed by Petersen, Schmidt/Neuper and VDI 2230, theoretically expressing a relation between bolt tension and external force, were compared to evaluate the suitability of the FE analysis and analyze the significant behavior characteristics of the connection. Furthermore, the changes in the bolt-load curve due to the variations in the partial dimensions of the L-type flange bolt connection were analyzed.