• Journal of the Korean Society for Railway
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• v.20 no.4
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• pp.440-447
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• 2017

Spectrum level for the acoustic roughness of wheels and rail surface should be periodically maintained under the limitation of ISO to reduce rolling noise of railway vehicles. Thus, in maintaining railway track, displacement sensor-based measuring devices are broadly used to measure the surface roughness and to perform spectral analysis. However, these measuring devices cause unexpected measuring errors since the displacement sensors are fixed at moving platforms and the main frame produces pitching motion during measurement. To increase the accuracy of the measured values, this paper has investigated the effects of design variables such as wheel base, additional wheels, and elastic deformation of wheels on the surface roughness and acoustic roughness spectrum.

• Journal of the Korean institute of surface engineering
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• v.56 no.4
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• pp.273-282
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• 2023

In this study, the surface of Polyetheretherketone (PEEK) disks was modified to have a hydrophilic surface by applying a coating of Polyethylene glycol (PEG), Hyaluronic acid(HA), and Poly-Dopamine(PDA). The investigation aimed to examine whether the coated surfaces showed enhanced bioactivity for orthopedic applications compared to the pure PEEK. The microstructure, surface characteristics, and wettability of PEEK coated with PEG, HA, and PDA were analyzed using scanning electron microscopy(SEM), FT-IR spectrophotometer, Roughness Measurement System, Micro-Vickers, and Contact angle measurement. The mechanical properties were analyzed using a tensile testing machine, while the MTT assay for cell activity was analyzed using a microplate reader to measure optical density. According to the SEM and FT-IR results, the composition and crystal structure of PEG, HA and PDA coated surface were verified. Also, roughness, hardness, and contact angle were all improved in the coating group compared to the pure PEEK. We checked the HepG2 cell proliferation by using MTT assay on 7th days. In MTT assay results, HepG2 cell proliferation was increased with time, at 7 days, cell viability on discs coated with PDA was significantly higher than pure PEEK, PEG, HA coated group. PDA coated PEEK exhibited the highest surface roughness, hardness, contact angle, and cell activity. The mechanical properties were not affected by the presence of the coating.

• Journal of Periodontal and Implant Science
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• v.38 no.1
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• pp.67-74
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• 2008

Purpose: The aim of this study was to evaluate the effect of Er:YAG laser on microstructure and roughness of $TiO_2$ blasting implant surface. Materials and Methods: Ten $TiO_2$ blasting implant were used in this experiment. One implant was control group, and nine $TiO_2$ blasting implant surfaces were irradiated with Er:YAG laser under 100 mJ/pulse, 140 mJ/pulse, and 180 mJ/pulse condition for 1 min, 1.5 min, and 2 min respectively. Optical interferometer and scanning electron microscopy was utilized to measure roughness and microstructure of specimens. Results: The surface roughness was decreased after Er:YAG laser irradiation in all groups, but there was no significant difference. 100 mJ/pulse and 140 mJ/pulse group did not alter the $TiO_2$ blasting implant surface in SEM study while 180 mJ/pulse group altered the $TiO_2$ blasting implant surface. Implant surfaces showed melting, microfracture and smooth surface in 180 mJ/pulse group. Conclusion: Detoxification of implant surface using Er:YAG laser must be irradiated with proper energy output and irradiation time to prevent implant surface alteration.

• Journal of Korean Society for Atmospheric Environment
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• v.2 no.1
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• pp.23-31
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• 1986

Meteorological Measurement was performed for evaluation of the horizontal vertical standard deviation $(\sigma_y, \sigma_z)$, surface roughness length and stmospheric stability during the period of March to October 1985 The major results are as follows; 1) The average value of surface roughness length was 144cm at NEPI. 2) In frequency distribution of atmospheric stability, neutral state (D class) was dominent in Seoul (29%) and Pusan (30%). Unstable states (A. B. C. class) were 26% in Seoul and 24% in Pusan. Also, stable states (D. E. F class) were 74% in Seoul and 76% in Pusan. 3) Standard deviations of horizontal ad vertical direction were evaluated as a function of downwind distance and atmospheric stability at NEPI, Jamsil and Pujeondong (Pusan). Standard deviation of horizontal direction was largest at NEPI among 3 areas because of mechanical turbulence resulting from difference of surface roughness length.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.5
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• pp.1-8
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• 2001

A measuring system is developed to acquire static image from rotary state through CCD camera in back light illumination by synchronizing chopper to workpiece. In image processing of acquired image, lowpass filter is very useful in view of noise removal, and optimum binary image can be made through histogram equalization which is one of the histogram technique to maximize brightness intensity between workpiece and background. After image treatment applying Laplacian operator, surface roughness is calculated by introducing conversion coefficient of pixel which edge is composed of.

• Journal of the Korean Applied Science and Technology
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• v.15 no.3
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• pp.47-53
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• 1998

The polyimide film surface was modified with KOH aqueous solutions or sulfuric acid. The film thickness was increased by about 10% through the modification of film surface. Hydrolysis of amide bonds and hydration of water induced the increase. The polarity of the film surface increased and identified by contact angle measurement. The depth and roughness of modified was increased. After treatment of surface with water, alkyl and 4-pentyloxyaniline were introduced on the film surface by complex formation between anionic species formed on the imide surface and ammonium ion. The newly introduced alkyl group was identified by FT-IR spectroscopy. Surface polarity reduced dramatically and the roughness was increased after introduction of ammonium salt.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.6
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• pp.795-804
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• 2007

Statement of problem. Nano-scale calcium-phosphate coating on the anodizing titanium surface using ion beam-assisted deposition (IBAD) has been recently introduced to improve the early osseointegration. However, not much is known about their surface characteristics that have influence on tissue-implant interaction. Purpose. This study was aimed to investigate microtopography, surface roughness, surface composition, and wettability of the titanium surface modified by the anodic oxidation and calcium phosphate coating using IBAD. Material and methods. Commercially pure titanium disks were used as substrates. The experiment was composed of four groups. Group MA surfaces represented machined surface. Group AN was anodized surface. Group CaP/AN was anodic oxidized and calcium phosphate coated surfaces. Group SLA surfaces were sandblasted and acid etched surfaces. The prepared titanium discs were examined as follows. The surface morphology of the discs was examined using SEM. The surface roughness was measured by a confocal laser scanning microscope. Phase components were analyzed using thin-film x-ray diffraction. Wettability analyses were performed by contact angle measurement with distilled water, formamide, bromonaphtalene and surface free energy calculation. Results. (1) The four groups showed specific microtopography respectively. Anodized and calcium phosphate coated specimens showed multiple micropores and tiny homogeneously distributed crystalline particles. (2) The order of surface roughness values were, from the lowest to the highest, machined group, anodized group, anodized and calcium phosphate deposited group, and sandblasted and acid etched group. (3) Anodized and calcium phosphate deposited group was found to have titanium and titanium anatase oxides and exhibited calcium phosphorous crystalline structures. (4) Surface wettability was increased in the order of calcium phosphate deposited group, machined group, anodized group, sandblasted and acid etched group. Conclusion. After ion beam-assisted deposition on anodized titanium, the microporous structure remained on the surface and many small calcium phosphorous crystals were formed on the porous surface. Nanoscale calcium phosphorous deposition induced roughness on the microporous surface but hydrophobicity was increased.

• Korean Journal of Materials Research
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• v.16 no.9
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• pp.543-549
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• 2006

Polyimides (PI) are treated with $He/O_2$ and $He/O_2/NF_3$ atmospheric pressure rf dielectric barrier discharge in order to investigate the roles of $NF_3$ that is one of the PI etching gases. Surface changes are analyzed by x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and contact angle measurement. The surface roughness of PI and the ratio of C=O, which is hydrophilic functional group, is more increased by $He/O_2/NF_3$ discharge than by $He/O_2$ discharge. The C=O species on the PI surface is increased up to 30 percent with rf power. The surface roughness of PI is increased from 0.4 to 11 nm with rf power. The water drop contact angles on PI, however, are reduced from $65^{\circ}\;to\;9^{\circ}$ by plasma treatment independently of $NF_3$.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.5 s.176
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• pp.1254-1260
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• 2000

There have been many developments in super precision working technique and working method up to, now. But, it is very difficult to evaluate working surface accurately without the technicians experience and judgment. Surface roughness tester using stylus was used to measure surface condition generally But this method is not so desirable because of damage on test piece caused by contact between the workpiece and the stylus sensor. As a result, non-contact method was known as a good way to carry, out this process without damage. However, this is a difficult one among the various measuring methods. So we are tying to suggest a new method using texture analysis through image processing to get a surface information in worked test piece. Co-occurrence matrix using difference of gray levels between a pixel and its neighboring one was used to study behavior of surface roughness and to J acquire data for analysis. Standard specimen was adapted to verify this research. We suggest texture information method in order to evaluate surface state for the best measurement system.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.04a
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• pp.515-528
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• 1995

Slips and falls are the major causes of the pedestrian injuries in the industry and the general community throughout the world. With the awareness of these problems, the friction coefficients of the interface between floorings and footwear have been measured for the evaluation of slip resistant properties. During this measurement process, the surface texture has been shown to be substantially effective to the friction mechanism between shoe heels and floor surfaces under various types of walking environment. Roughness, either of the floor surface or shoe heels, provides the necessary drainage spaces. This roughness can be designed into the shoe heel but this is inadequate in some cases, especially a wear. Therefore, it is essential that the proper roughness for the floor surface coverings should be provided. The phenomena that observed at the interface between a sliding elastomer and a rigid contaminated floor surface are very diverse and combined mechanisms. Besides, the real surface geometry is quite complicate and the characteristics of both mating surfaces are continuously changing in the process of running-in so that a finite number of surface parameters can not provide a proper description of the complex and peculiar shoe - floor contact sliding mechanism. It is hypothesised that the interface topography changes are mainly occurred in the shoe heel surfaces, because the general property of the shoe is soft in the face of hardness compared with the floor materials This point can be idealized as sliding of a soft shoe heel over an array of wedge-shaped hard asperities of floor surface. Therefore, it is considered that a modelling for shoe - floor contact sliding mechanism is mainly depended upon the surface topography of the floor counterforce. With the model development, several surface parameters were measured and tested to choose the best describing surface parameters. As the result, the asperity peak density (APD) of the floor surface was developed as one of the best describing parameters to explain the ambiguous shoe - floor interface friction mechanism. It is concluded that the floor surface should be continuously monitored with the suitable surface parameters and kept the proper level of roughness to maintain the footwear slip resistance. This result can be applied to the initial stage of design for the floor coverings.