• Proceedings of the IEEK Conference
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• 2002.06b
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• pp.45-48
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• 2002

This paper discusses the surface roughness of negative chemically amplified resists, SAL601 exposed by I-beam direct writing. system. Surface roughness, as measured by atomic force microscopy, have been simulated and compared to experimental results. Molecular-scale simulator predicts the roughness dependence on material properties and process conditions. A chemical amplification is made to occur in the resists during PEB process. Monte-Carlo and exposure simulations are used as the same program as before. However, molecular-scale PEB simulation has been remodeled using a two-dimensional molecular lattice representation of the polymer matrix. Changes in surface roughness are shown to correlate with the dose of exposure and tile baking time of PEB process. The result of simulation has a similar tendency with that of experiment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.627-628
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• 2006

High speed milling process is emerging as an important fabrication process benefits include the ability to fabricate micro and meso-scale parts out of a greater range of materials and with more varied geometry. It also enables the creation of micro and meso-scale molds for injection molding. Factors affecting surface roughness have not been studied in depth for this process. A series of experiments has been conducted in order to begin to characterize the factors affecting surface roughness and determine the range of attainable surface roughness values for the high speed milling process. It has previously been shown that run-out creates a greater problem for the dimensional accuracy of pans created by high speed milling process. And run-out also has a more significant effect on the surface quality of milled parts. The surface roughness traces reveal large peak to valley variations. This run-out is generated by spindle dynamics and tool geometry. In order to investigate the relationship between tool alignment errors and surface roughness the scallop generating mechanism in the ball-end milling with tool alignement errors has been studied and simulated. The results indicate that tool alignment errors have no significant effects ell the dimension of scallops in for flat planes.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1237-1242
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• 2007

For the various RP processes and machines, quantitative comparisons were carried out, which include the variations of roughness according to inclined angle of surface, tensile strength and heat-resistance, shape accuracy affected by curl distortion, manufacturability of submilli-scale structure, and manufacturing speed. It was observed that steeper surface results in smoother roughness except Eden500V of Objet. Specimen made by LOM process showed the best heat-resistance, but that of SL process had heat-resistance only up to $60^{\circ}C$. Generally, tensile strength in the building direction was shown to be smaller than in the scanning direction, but SL process showed the opposite results. RM6000II of CMET was superior in the manufacturing small-scale structure below 0.2mm, and Z510 of Zcorp. and ViperPRO of 3D systems were great in manufacturing speed.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2000.04a
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• pp.138-143
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• 2000

In order to investigate the relationship between fabric sound parameters and subjective sensation, each sound from 60 fabrics was recorded and analyzed by Fast Fourier transform. Level pressure of total sound (LPT), three coefficients (ARC, ARF, ARE) of auto regressive models, loudness (Z), and sharpness (Z) by Zwickers model were estimated as sound parameters. For subjective evaluation, seven sensation (softness, loudness, sharpness, clearness, roughness, highness, and pleasantness) was rated by both semantic differential scale (SDS) and free modulus magnitude estimation (FMME). As the results, the ARC values were positively proportional to both LPT and loudness (Z) values. In both of SDS and FMME, softness, clearness, and pleasantness were negatively correlated with loudness, sharpness, roughness, and highness. In regression models, softness and clearness by FMME were negatively affected by LPT뭉 ARC, while loudness, sharpness, roughness, and highness were positively expected. Regression models for pleasantness showed low values for R2.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.4
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• pp.269-283
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• 2005

To figure out the cause of underestimating the roughness and shear strength of rock joints suggested by numerous researchers, we analyzed roughness mobilization characteristics, characteristics of roughness parameters, effects of sampling interval, and waviness for roughness parameters. It was found out that lack of understanding of the roughness mobilization characteristics, inappropriate applications of roughness parameters, and effect of aliasing provide a main reasons for those problems. Several practical alternatives for improving those problems were suggested. As far as digitizing methods are concerned, we can find that using a 3D scanner can give a relatively effective result. To avoid aliasing, sampling interval should be less than one-quarter of the minimum asperities. As for the quantification of roughness, it was analyzed that the roughness parameter should be classified into two components depending on the scale of roughness to apply the shear strength model. For classifying the roughness, a framework of the criterion was suggested based on the plastic flow concept for the asperity failure, and the basis for proposing a new alternative shear strength model was established.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.5
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• pp.514-520
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• 2009

In configuring an automated polishing system, a monitoring scheme to estimate the surface roughness is necessary. In this study, a precision polishing process, magnetic abrasive finishing (MAF), along with an in-process monitoring setup was investigated. A magnetic tooling is connected to a CNC machining to polish the surface of stavax(S136) die steel workpieces. During finishing experiments, both AE signals and force signals were sampled and analysed. The finishing results show that MAF has nano scale finishing capability (upto 8nm in surface roughness) and the sensor signals have strong correlations with the parameters such as gap between the tool and workpiece, feed rate and abrasive size. In addition, the signals were utilized as the input parameters of artificial neural networks to predict generated surface roughness. Among the three networks constructed -AE rms input, force input, AE+force input- the ANN with sensor fusion (AE+force) produced most stable results. From above, it has been shown that the proposed sensor fusion scheme is appropriate for the monitoring and prediction of the nano scale precision finishing process.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.255-262
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• 1999

This paper summarizes the results of a study which uses the recently developed Optical Profile Microscopy technique (Dove and Frost, 1996) as the basis for investigating the role of geomembrane surface roughness on the shear strength of goomembrane/geotextile interfaces. The results show that interface friction can be quantitatively related to the surface roughness of the geomembrane. The peak and residual interface strengths increase dramatically through the use of textured geomembranes as opposed to smooth geomembranes. For the smooth geomembranes, the sliding of the geotextile is the main shear mechanism. For the textured geomembranes, the peak interface strength is mainly mobilized through the micro-texture of the geomembrane, however, the residual interface strength is primarily attributed to macro scale surface roughness which pulls out and breaks the filaments from the geotextile. The results of this study can be extended to the other interfaces such as joints in rock mass, and also can be used to provide a quantitative framework that can lead to a significantly improved basis for the selection and design of geotextiles and geomembranes in direct contact.

• Macromolecular Research
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• v.12 no.5
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• pp.437-442
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• 2004

We have fabricated a polymeric waveguide by using a hot embossing technique and have investigated its propagation loss. The replication of waveguide channels through the use of a hot embossing technique is of interest as a single-step process that could deliver surface roughnesses far smaller than the wavelength. We have evaluated experimentally that the sidewall roughness has a dominant effect on insertion losses of the multimode polymeric waveguide. The propagation loss of the waveguide decreased dramatically upon decreasing the sidewall roughness of the channel. We have confirmed that the preparation of waveguides having nanometer-scale sidewall roughness and 0.1 dB/cm propagation loss is possible when using the hot embossing technique.

• The Journal of Engineering Geology
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• v.15 no.3
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• pp.269-280
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• 2005

We assigned points on surface of standard roughness profile by 0.1mm along the length and measured coordinates of points. Then, the lengths of profile were measured with different scales using modified divider method. The fractal dimensions and intercepts of slopes were determined by plotting the length vs scale in log-log scale. The fractal dimensions as well as intercepts of slopes show well correlation with joint roughness coefficients(JRC). However, multiplication of the kactal dimension by intercept show better correlation with IRC and we derived a new equation to estimate JRC from fractal dimension and intercept. The crossover length in which we can determine the correct fractal dimension was between 0.3-3.2mm. We measured joint roughness of 26 natural joints and calculated JRC using the equation suggested by Tse and Cruden(1979) and new equation derived by us. IRC values calculated by both equations are almost the same, indicating new equation is effective in measuring IRC.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.36-37
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• 2006

This study aims to investigate the usage of nano-scale particles in a micro metal injection molding ($\mu$-MIM) process. Nanoscale particle is effective to improve transcription and surface roughness in small structure. Moreover, the effects of hybrid micro/nano particles, Cu/Cu and SUS/Cu were investigated. Small dumbbell specimens were produced using various feedstocks prepared by changing binder content and fraction of nano-scale Cu particle (0.3 and $0.13{\mu}m$ in particle size). The effects of adding the fraction of nano-scale Cu powder on the melt viscosity of the feedstock, microstructure, density and tensile strength of sintered parts were discussed.