• Journal of the Korean Society of Clothing and Textiles
• /
• v.28 no.3_4
• /
• pp.491-498
• /
• 2004

Among the components of disposable diaper, the top sheet contacting with baby skin directly is usually made of nonwoven fabrics. Therefore, the tactile properties of the nonwoven fabrics are important for the skin health of infants. In this study, we have explored the surface properties of hygiene nonwoven fabrics (100% cotton spunlace, 100% tencel spunlace, 100% polypropylene (PP) thermalbonding and 100% PP Thru-air bonded carded web (TABCW)), such as friction coefficient and geometrical roughness. used by KES-F system and a laser displacement sensor. Also, we evaluated the subjective responses about the hygiene nonwoven fabrics used by a questionnaire and compared with the objective values, measured by KES-F system and a laser displacement sensor respectively. From the result, we have found that surface sensation (such as soft, smooth, and rough) and bulkiness sensation (such as spongy and fluffy) of nonwovens were represented excellently by L-SMD values which are measured by a laser displacement sensor.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2003.11a
• /
• pp.201-209
• /
• 2003

In the mixed lubrication regime, the roughness effects are very important due to the presence of interacting asperities. An average Reynolds equation using flow factors is very useful to determine effects of surface roughness on mixed lubrication. In this paper, the pressure flow factors and shear stress factor for Gaussian and non-Gaussian surfaces are evaluated in terms of kurtosis and skewness. particularly, the elastic deformation of the surface is considered.

• Journal of Powder Materials
• /
• v.25 no.2
• /
• pp.99-103
• /
• 2018

Spherical monosized pure aluminum (Al) particles are successfully fabricated by the pulsated orifice ejection method (POEM). The surface reaction between Al and the graphite crucible is investigated by analysing the microstructure and chemical composition of the materials. No significant chemical reaction occurs between Al and the graphite owing to the crystalline Al oxide (${\gamma}-Al_2O_3$) layer generated in the initial state. The ${\gamma}-Al_2O_3$ layer is clearly observed in all regions between the Al particles and graphite via transmission electron microscopy and confirmed by the selected area diffraction pattern. The morphology of the ${\gamma}-Al_2O_3$ layer perfectly follows the surface morphology of the graphite crucible, which showed nanoscale roughness. This implies that molten Al could not directly contact graphite even though the surface of the crucible became rough to some extent. However, this passivation phenomenon allowed the successful fabrication of monosized pure Al particles. Therefore, POEM is a useful process at least to manufacture monosized pure Al particles.

• Journal of the Korean institute of surface engineering
• /
• v.18 no.2
• /
• pp.53-60
• /
• 1985

The microstructure of zine electrodeposits was investigated by using zinc sulfate solution in still bath. The cathode current efficiency decreased with increasing current density, and decreasing temperature. The preferred orientation of the zinc electrodeposits changed from (10.3) texture to(10.${\ell}$)-(00.1)(${\ell}$=1, 2, 3) texture through (10.2)-(10.3) preferred orientation with increasing cathode over potential. The surface morphology of zinc electrodeposits changed from the dendritic growth with granular crystallites to the blocks of hexagonal crystallites packed together with increasing current density. The microstructure of cross section of the above deposits are the rough granular structure and columnar structure respectively.

• Proceedings of the KIEE Conference
• /
• 1987.11a
• /
• pp.286-289
• /
• 1987

The measurements of prebreakdown currents and breakdown voltages have been made for smooth rough, protrusion plane parallel stainless steel electrodes in vacuum ($10^{-5}$ torr), as a function of electrode separation, in the range $0.4{\sim}2.4mm$ using DC source($0{\sim}200KV$). Thee prebreakdwon currents of a each condition are found to be consistent with the Fouler-Nondheim field emission theory. The effect of the electrode surface condition on the local field enhancement factors, prebreakdown currents, and on the breakdown voltages are shown. The breakdown mechanism of a small vacuum gap was ascertained as the field emission corresponding the F-N theory. Therefore, these results suggest that the field emission currents following the electrode surface condition play a major role for initiation of DC breakdown.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.30A no.6
• /
• pp.1-7
• /
• 1993

After the 1%S-Al metal is deposited, a thin oxide is formed thereon. Then, a single charged Argon(Ar$^{+}$) is ion implanted into the oxide layer, thereby causing the metal grain in the upper surface of the metal layer to become amorphous. Consequently, the grain size will be reduced and the rough surface of the metal layer flattened. However, the remainder of the metal layer beneath the upper surface thereof will still exhibit large grain size and low resistance, because the Argon ion is only implanted to characterized by a dual-sized grain structure which served to reduce interlayer stress, thereby decreasing the rate of stress migration, and to lower the resistivity of the metal line, thereby enhancing the electromigration characteristic thereof. Experiments have shown that the metal line exhibits a metal migration rate which is approximately 700% less than the control group and a standard deviation which is approximately 200% less than these group.p.

• Journal of the Korean institute of surface engineering
• /
• v.19 no.3
• /
• pp.109-120
• /
• 1986

The electroless nickel plating on high alumina ceramics was performed in the bath containing nickel chloride, sodium hypophosphite and mono- or bi-carboxylic acid as a complexing agent in order to examine the empirical rate law as well as the effects of the complexing agent, plating temperature and pH on the rate of deposition. Adding the carboxylic acid to the plating bath, the rate of deposition was increased considerably, and each of the complexing agents showed a maximum deposition rate plateau around a particular concentration of the complexing agent. The rate of deposition was increased with increasing either temperature or pH, but microstructure of the surface became more rough. Furthermore, empirical rate law of the elecltroless nickel deposition on high alumina ceramics was discussed with the activation energy and other rate parameters calculated.

• Journal of Korean Society of Water and Wastewater
• /
• v.19 no.2
• /
• pp.193-199
• /
• 2005

The objective of this study was to investigate the characteristics of adhesion and detachment of algae on various materials of drainage canal in the sedimentation basin. The influence of surface washability, surface roughness, phosphorous concentration was studied using stainless steel, cement block and ceramic panel. The algae attached content of cement block was higher than that of the ceramic coating panel. The attachment varied significantly with respect to exposure time and different materials. the attachment was higher on rough surface (cement block) when compared to smooth surfaces. The content of attached algae increased with increasing phosphorous concentration in water. The detachment efficient of algae was higher on ceramic panel.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.616-621
• /
• 2005

Most machine element, such as gears and bearings, are operated in the mixed lubrication region. Contact between two asperities has an effect on machine life by increasing local pressure. To estimate fatigue lift exactly, asperity contact should be considered as a factor of fatigue liff because this happening produce friction, abrasion and make flash temperature. In this paper, asperity contact is considered as a result of film breakdown when lubricant pressure is not enough to separate two asperities. Contact pressure is calculated to asperity overlap region and added to lubricant pressure. For this model, numerical procedure is introduced and the result on surface roughness and velocity for wheel bearing is presented. Results of EHL analysis for wheel bearing show that asperity contact is occurred at the edge of EHL conjunction where has a insufficient lubricant pressure to separate two surface.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.30 no.3
• /
• pp.282-289
• /
• 2010

Most nondestructive testing techniques require good contact between the sensor and tested concrete surface to obtain reliable data. But the surface preparation is often very time and labor consuming due to the rough surface or limited access of concrete structures. One approach to speed up the data collection process is to eliminate the need for physical contact between the sensor and tested structure. Non-contact air-coupled sensing technique can be a good solution to this problem. An obvious advantage of the non-contact air-coupled sensing technique is which can greatly speed up the data collection in field and thus the damage detection process can be completed very rapidly. In this article, recent developments in non-contact air-coupled sensing technique for rapid detection of damages in concrete structures are summarized to evoke interest, discussion and further developments on this technique to a NDT research community in Korea. It is worth noting that the works in this article have been published in the types of thesis, proceedings, and journals. All published sources are cited in the text and listed in reference.