• Structural Engineering and Mechanics
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• v.89 no.4
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• pp.349-362
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• 2024

High-performance fiber-reinforced cement composites (HPFRCC) are new materials created and used to repair, strengthen, and improve the performance of different structural parts. When exposed to tensile tension, these materials show acceptable strain-hardening. All of the countries of the globe currently seem to have a need for these building materials. This study aims to create a low-carbon HPFRCC (high ductility) that is made from materials that are readily available locally which has the right mechanical qualities, especially an increase in tensile strain capacity and environmental compatibility. In order to do this, the effects of fiber volume percent (0%, 0.5%, 1%, and 2%), and determining the appropriate level, filler type (limestone powder and silica sand), cement type (ordinary Portland cement, and limestone calcined clay cement or LC3), matrix hardness, and fiber type (ordinary and oxygen plasma treated polypropylene fiber) were explored. Fibers were subjected to oxygen plasma treatment at several powers and periods (50 W and 200 W, 30, 120, and 300 seconds). The influence of the above listed factors on the samples' three-point bending and direct tensile strength test results has been examined. The results showed that replacing ordinary Portland cement (OPC) with limestone calcined clay cement (LC3) in mixtures reduces the compressive strength, and increases the tensile strain capacity of the samples. Furthermore, using oxygen plasma treatment method (power 200 W and time 300 seconds) enhances the bonding of fibers with the matrix surface; thus, the tensile strain capacity of samples increased on average up to 70%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05b
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• pp.25-28
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• 2005

This paper was investigated the changes of surface properties of high-temperature-vulcanized(HTV) semiconductive silicone rubber due to oxygen plasma discharge. The modifications produced on the silicone surface by oxygen plasma were accessed using x-ray photoelectron spectroscopy(XPS), contact angle and Scanning Electron Microscope(SEM). The results of the chemical analysis showed that C-H bonds were broken due to plasma discharge and Silica-like bonds (SiOx. x=3~4) increased. It is thought that the above changes lead to the increase of surface energy of high-temperature-vulcanized(HTV) semiconductive silicone rubber. The micromorphology of surface and hydrophobicity due to plasma discharge based on our results were discussed.

• Electrical & Electronic Materials
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• v.9 no.9
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• pp.918-924
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• 1996

A downstream oxygen plasma is generated by capacitively coupled RF power and applied to photoresist stripping. Stripping rate (ashing rate) is measured in terms of RF power, chamber pressure, oxygen flow rate and temperature. Ashing reaction is thermally activated and depends on oxygen radical density. The ashing process is optimized to have the high ashing rate, good uniformity and minimal plasma damage using a statistical method.

• Applied Chemistry for Engineering
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• v.30 no.6
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• pp.719-725
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• 2019

In this study, activated carbon fibers were treated with oxygen plasma to investigate gas sensing properties of the dimethyl methylphosphonate (DMMP), which is a simulant gas of the chemical warfare agent, according to oxygen functional group contents. As the flow rate of oxygen plasma treatment increased, oxygen groups were introduced to the surface of activated carbon fibers from 6.90 up to 36.6%, increasing the -OH group which influences the DMMP gas sensing properties. However, as the flow rate of oxygen plasma increases, the specific surface area tends to decrease because etching on the surface of activated carbon fibers occurs due to active species generated during the oxygen plasma treatment. The resistance change rate of the DMMP gas sensor increased from 4.2 up to 25.1% as the oxygen plasma treatment flow rate increased. This is attributed to the hydrogen bonding between DMMP gas and introduced hydroxyl functional group on activated carbon fibers by the oxygen plasma treatment. Therefore, the oxygen plasma is considered to be one of the important surface treatment methods for detecting chemical warfare agents at room temperature.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.12
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• pp.113-118
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• 2010

For a present study, woven type carbon fibers were surface-modified by oxygen plasma to improve adhesive strength between carbon fibers and epoxy. The change of hydrophilic properties by the plasma modification was investigated through the contact angle measurement and the calculation of surface energy of carbon fiber due to the oxygen plasma modification. FESEM and XPS analyses were performed to study the chemical and physical changes on the surface of carbon fibers due to the oxygen plasma modification. Pin-on-disk wear tests were conducted under dry condition using unmodified and plasma-modified carbon/epoxy composites to investigate the effect of plasma modification on the wear behavior of woven type carbon/epoxy composites. The results showed that the friction coefficient and the wear rate of plasma-modified carbon/epoxy composites were lower than those of unmodified carbon/epoxy composites, respectively. XPS analysis showed that new functional group of a carbonyl type was created on the carbon fibers by the $O_2$ plasma treatment, which enhanced adhesive strength between carbon fibers and epoxy, leading to improve wear properties

• Applied Science and Convergence Technology
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• v.27 no.1
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• pp.5-8
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• 2018

In this paper, plasma treatment effects on a ploy(dimethyl siloxane) substrate were analyzed for the applications of stretchable silver nanowire (Ag NWs) electrodes. The oxygen plasma treated sample shows the best performance compared to nitrogen treated and untreated samples. The lowest sheet resistance and reasonable stretching capability was achieved up to 20% strain condition without open circuit fail for the oxygen plasma treated sample.

• Journal of the Korean Society of Combustion
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• v.8 no.1
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• pp.9-16
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• 2003

Carbon soot emission from combustion processes, especially from diesel engines, is a subject of growing concern since soot is known to seriously affect human health. Efforts have been made to oxidize soot particles utilizing Non-Thermal Plasma(NTP) techniques. When oxygen is carried into a plasma device, electrons generated by the plasma dissociate the oxygen, resulting in the formation of oxygen atoms. These highly activated atoms, called O radicals, are known as strong oxidizing agent. This paper presents concentration variations of CO and $CO_2$ at the exit of the plasma device, resulting from the soot oxidation by O radicals, with variations of inlet oxygen concentration, gas temperature, and gas flow rate. Based on the data, Arrehenious rate constants of reactions between C(s)+O and C(s)+O+O were proposed.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.215-215
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• 2014

Red color light emitting diodes (LEDs) were fabricated using CdSe/CdZnS quantum dots (QDs). During the device fabrication process, oxygen plasma treatment on the ITO surface was performed to improve the interfacial contact between ITO anode and the hole injection layer. CdSe/CdZnS quantum dots were cross-linked to remove their surrounded organic surfactants. The device shows red emission at 622 nm, which is consistent with the dimension of the QDs (band gap=1.99 eV). The luminance shows 6026% improvement compared with that of LEDs fabricated without oxygen plasma treatment and quantum dots cross-linking process. This approach would be useful for the fabrication of high-performance QLEDs with ITO electrode and PEDOT:PSS hole injection layers.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.6
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• pp.454-459
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• 2020

In this study, a TiO₂/TiO_2-x-based resistance variable memory was fabricated using a DC/RF magnetron sputtering system and ALD. In order to analyze the effect of oxygen plasma treatment on the performance of resistance random access memory (ReRAM), the TiO₂/TiO_2-x-based ReRAM was evaluated by applying RF power to the TiO_2-x oxygen-holding layer at 30, 60, 90, 120, and 150 W, respectively. The ReRAM was fabricated, and the electrical and surface area performances were compared and analyzed. In the case of ReRAM without oxygen plasma treatment, the I-V curve had a hysteresis curve shape, but the width was very small, with a relatively high surface roughness of the oxygen-retaining layer. However, in the case of oxygen plasma treatment, the HRS/LRS ratio for the I-V curve improved as the applied RF power increased; stable improvement was also noted in the surface roughness of the oxygen-retaining layer. It was confirmed that the low voltage drive was not smooth due to charge trapping in the oxygen diffusion barrier layer owing to the high intensity ReRAM applied with an RF power of approximately 150 W.

• Journal of the Semiconductor & Display Technology
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• v.2 no.4
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• pp.9-12
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• 2003

This paper describes a newly developed simulation environment for analysis and design of a plasma processing chamber based on first principles including complicated physical and chemical interactions of plasma, fluid dynamics of neutrals, and transport phenomena of particles. Capabilities of our simulator, named VIP-SEPCAD (Virtual Integrated Prototyping Simulation Environment for Plasma Chamber Analysis and Design), are demonstrated through a two dimensional simulation of an oxygen plasma chamber. VIP-SEPCAD can provide plasma properties such as spatiotemporal profiles of plasma density and potential, electron temperature, ion flux and energy, etc. By coupling neutral and particle transport models with a three moment plasma model, VIP-SEPCAD can also predict spatiotemporal profiles of chemically reactive species and particles exist in plasma.