• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.9 no.1
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• pp.47-52
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• 1998

Objectives : To compare the objective differences in voice quality and voice problems between clergies and normal male control group. Materials and Methods : The sustained vowel sound of 46 clergies and 40 normal persons were analyzed, using a videostroboscopy and acoustic analyzer. Together with these analyses, a questionnaire associated with current and past voice problems was handed over to the patients. Results : The most common symptom in subjective group was the voice fatigue. Stroboscopic findings in subjective group were as following 23 cases(50%) of pachydermia, 17 cases(37%) of phase difference, 12 cases(25%) of anterior-posterior contracture, 6 cases(13%) of vocal polyp and 3 cases(7%) of vocal nodule. The mean maximal phonation time in clergies was 17.8 seconds and in control group was 19 seconds. litter, pitch perturbation quotient and shimmer were significantly increased in subjective group than in control group(p<0.05), but there were no significant differences between two groups in fundamental frequency, vFo, amplitude perturbation quotient and noise to harmonic ratio. Conclusion : In the clergies using loud and forceful voice, vocal polyp and functional voice disorder findings were frequently noted in stroboscopic examination. litter and shimmer, reflecting the roughness of voice, were increased in acoustic analysis. Therefore, clergies, classified into untrained professional voice users, need professional career guidance and counseling.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.10 no.2
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• pp.154-163
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• 1999

GRBAS scale, the tool fir the perceptual evaluation of voice, demands the experience of judges, and MDVP parameters of CSL, the tool for the objective measurements of voice quality demands the exact interpretation of the analyzed results. The two tools should be used as compensatory evaluation methods, so the experimental study was performed to investigate the correlation between GRBAS scales and MDVP parameters by using the pathologic voice of the 30 patients with vocal polyps, and to know the significant MDVP parameters which the inexperienced GRBAS scale judges should attend to. The 30 subjects voices, saved in MDVP of CSL were analyzed by its own analysis program, and three experienced voice therapists judged the same voices by using GRBAS scales. The correlations between them were analyzed by Spearman Rank Correlation Coefficient. As results, among the 29 MDVP parameters, 22 parameters showed statistically significant correlation with Grade(G) scale(p＜0.05). And it was found that Roughness(R) scale showed significant correlation with 18 parameters, Breathiness(B) scale with 17 parameters, Strain(S) scale with 12 parameters. In Asthenicity(A) scale, no parameter showed significant correlation. On the whole, significantly high correlation were found in the parameters related with pitch ind amplitude perturbation, especially, the amplitude perturbation.

• Design & Manufacturing
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• v.10 no.2
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• pp.50-54
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• 2016

In the semiconductor industry the final products were checked for several environments before sell the products. The burning test of memory and chip was implemented in reliability for all of parts. The memory and chip were developed to high density memory and high performance chip, so circuit design was also high integrated and the test bed was needed to be thin and fine pitch socket. LGA(Land Grid Array) IC socket with thin wall thickness was designed to satisfy this requirement. The LGA IC socket plastic part was manufacture by injection molding process, it was needed accuracy, stiffness and suit resin with high flowability. In this study, injection molding process analysis was executed for 2 and 4 cavities moldings with runner, gate and sprue. The warpage analysis was also implemented for further gate removal process. Through the analyses the total deformations of the moldings were predicted within maximum 0.05mm deformation. Finally in consideration of these results, 2 and 4 cavities molds were designed and made and tested in injection molding process.

• Korean Journal of Applied Biomechanics
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• v.18 no.3
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• pp.1-10
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• 2008

One of the major factors affecting maneuverability of an athlete is frictional force caused at an outsole of his shoe. The magnitude of the frictional force is closely related to pattern and hardness of outsole and roughness of ground or floor. This study then focuses on the effect of outsole pattern of sports shoes on the frictional force. After surveying outsole patterns of sports shoes in markets, we select 4 types of outsole patterns, such as straight, W, O, and wave as primary outsole patterns of sports shoe and we also select depth, pitch and slope as design parameters of each pattern. Corresponding to those patterns and design parameters, various outsole specimen are prepared for frictional experiments. After performing frictional tests with those specimen, coefficients of friction(COF) are collected and analyzed with a statistical tool to draw useful conclusion.

• New & Renewable Energy
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• v.5 no.4
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• pp.21-27
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• 2009

Potential yield of micro wind turbine on the roof of urban high rise buildings is estimated. Urban wind profile is modeled as logarithmic profile above the mean building height with roughness length 0.8, displacement 7.5 m. Mean wind velocity from the meteorological agency data at the hight of 50m is used. Wind velocity changes are simulated on the rectangular roof of 26, 45, 53 degree pitch and the circular roof by computational fluid dynamics and RNG k-$\varepsilon$ turbulence models. Wind velocity increased approximately by a factor of the order of 270 % on the 26 degree pitched roof. In the 100 m and 200 m high buildings, wind enhancement is greater at the front side than at the center of the building. In the building arrangement model wind velocity changes abruptly and it becomes wind gusts. When commercial wind turbines are installed on the building roof, average power and annual power generation enhanced by 3~4 times than normal wind velocity at 50m and 6 kw wind turbine can generate 1053 kwh per month on the 26 degree pitched roof at 50m height and sufficiently supply electrical power with 15 household for common electrical use and food waste disposer. However, power output will vary significantly by the wind conditions in the order of $\pm$ 20 %.

• Journal of the Korean Society for Railway
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• v.17 no.5
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• pp.321-327
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• 2014

In this paper, linear dynamic equations are derived from nonlinear dynamic equations of constrained multibody systems using the QR decomposition method. The derived linear equations are applied to a railway vehicle bogie. The vibration characteristics of the railway vehicle are investigated by calculating the natural mode and transfer function of the bogie frame in relation to rail-roughness input. The main modes of the bogie were found below 35Hz, and the local modes above 198Hz. The magnitude of the vertical transfer function varied with the forward velocity due to vertical and pitch modes, which were influenced by the forward velocity. The magnitude of the lateral transfer function was negligibly small, and the mode in the longitudinal direction was excited for longitudinal transfer function regardless of the forward velocity.

• Journal of Astronomy and Space Sciences
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• v.18 no.3
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• pp.239-248
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• 2001

Far-ultraviolet IMaging Spectrograph (FIMS) is the main payload of the first Korean scientific satellite, KAISTSAT-4, which will be launched in 2002. Among the optical parts, parabolic cylinder mirror does not have any heritage from previous astronomical missions, so the manufacturing and testing process itself is a challenging issue. We describe the method of manufacturing and measuring of the off-axis parabolic cylinder mirror and our initial experiments to establish the entire manufacturing process. Using the method, the profile error can meet the specification of $lambda$ per cm which is closely related with the astronomical performances. In case of the surface roughness, temperature controlled pitch polishing reduces $R_{q}$ under 1 nm implying that scattering in the entire spectral range of FIMS is less than 2% of the incident UV light.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.16-22
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• 2008

We fabricated thermally-evaporated 10 nm-Ni/30 nm and 70 nm Poly-Si/200 nm-$SiO_2/Si$ structures to investigate the thermal stability of nickel silicides formed by rapid thermal annealing(RTA) of the temperature of $300{\sim}1100^{\circ}C$ for 40 seconds. We employed for a four-point tester, field emission scanning electron microscope(FE-SEM), transmission electron microscope(TEM), high resolution X-ray diffraction(HRIXRD), and scanning probe microscope(SPM) in order to examine the sheet resistance, in-plane microstructure, cross-sectional microstructure evolution, phase transformation, and surface roughness, respectively. The silicide on 30 nm polysilicon substrate was stable at temperature up to $900^{\circ}C$, while the one on 70 nm substrate showed the conventional $NiSi_2$ transformation temperature of $700^{\circ}C$. The HRXRD result also supported the existence of NiSi-phase up to $900^{\circ}C$ for the Ni silicide on the 30 nm polysilicon substrate. FE-SEM and TEM confirmed that 40 nm thick uniform silicide layer and island-like agglomerated silicide phase of $1{\mu}m$ pitch without residual polysilicon were formed on 30 nm polysilicon substrate at $700^{\circ}C\;and\;1000^{\circ}C$, respectively. All silicides were nonuniform and formed on top of the residual polysilicon for 70 nm polysilicon substrates. Through SPM analysis, we confirmed the surface roughness was below 17 nm, which implied the advantage on FUSI gate of CMOS process. Our results imply that we may tune the thermal stability of nickel monosilicide by reducing the height of polysilicon gate.

• Journal of the Microelectronics and Packaging Society
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• v.10 no.4
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• pp.73-79
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• 2003

With the variation of Ag concentration in bath, current density, duty cycle, additive and agitation for electroplating of Sn-Ag solder, the compositions and the morphologies of solder were studied. It was possible to controll Ag content in Sn-Ag solder by varying Ag concentration in bath and current density. The microstructure size of Sn-Ag solder decreased with increasing current density. Duty cycle of pulse electroplating and quantity of additive affected on Ag content of deposit and surface roughness. In this work eutectic Sn-Ag solder bumps with fine pitch of 30 $\mu\textrm{m}$ and height of 15 $\mu\textrm{m}$ was formed successfully. The Ag content of electrodeposited solder was confirmed by EDS and WDS analyses and the surface morphologies was analyzed by SEM and 3D surface analyzer.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.6
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• pp.176-183
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• 2002

Plasma Display Panel(PDP) is a type of flat panel display utilizing the light emission produced by gas discharge. Barrier Ribs of PDP separating each sub-pixel prevents optical and electrical crosstalks from adjacent sub-pixels. The mold for forming the barrier ribs has been newly researched to overcome the disadvantages of conventional manufacturing processes such as screen printing, sand-blasting and photosensitive glass methods. The mold for PDP barrier ribs have stripes of micro grooves transferring glass-material wall. In this paper , Stripes of grooves of which width 48$\mu$m, depth 124$\mu$m , pitch 274$\mu$m was acquired by machining of single crystal silicon with dicing saw blade. Maximum roughness of the bottom of the grooves was 59.6 nm Ra in grooving Si. Barrier ribs were farmed with silicone rubber mold, which is transferred from grooved Si forming hard mold. Silicone rubber mold has the elasticity, which enable to accommodate the waviness of lower glass plate of PDP. The methods assisted by the microwave and UV was adopted for reducing the forming time of glass paste.