• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.9
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• pp.2909-2915
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• 1996

Precise and accurate pressure measurements are obtained using deadweight piston gauges. Pressure distribution and elastic distortion in the piston-cylinder unit are the leading factors in determination of effective area. The distortion depends upon the pressure distribution in the clearance between piston and cylinder and those are coupled each other. Considering the viscosity pressure relation of oil and governing flow equation in the clearance, a new numerical iterative algorithm is developed. The disagreement between the monotonous and sharp pressure profiles is an indication that the pressure profile will be different for each piston and cylinder unit due to material variances.

• Journal of the Korean Vacuum Society
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• v.8 no.4A
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• pp.490-495
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• 1999

In 0.18 $\mu \textrm m$ LOGIC device, the etch rate of NMOS polysilicons is different from that of PMOS polysilicons due to the state of polysilicon to manufacture gate line. To control the etch profile, we tested the ratio of $Cl_2$/HBr gas and the total chamber pressure, and also we reduced Back He pressure to get the vertical profile. In the case of manufacturing the gate photoresist line, we used Bottom Anti-Reflective Coating (BARC) to protect refrection of light. As a result we found that $CF_4O_2$ gas is good to etch BARC, because of high selectivity and good photoresist line profile after etching BARC. in the results of the characterization of plasma damage to the antenna effect of gate oxide, NO type thin film(growing gate oxide in 0, ambient followed by an NO anneal) is better than wet type thin film(growing gate oxide in $0_2+H_2$ ambient).

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.572-577
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• 2004

This paper presents numerical study on the performance improvement of the sirocco fan in a range hood. The performance of sirocco fan means a higher flowrate, a higher static pressure and a lower required motor power in a fixed geometry constraint. Various impeller geometric parameters, such as blade profile, blade diameter, blade thickness profile and blade exit angle, were investigated by numerically and the results were compared with each other to know the effects on the performance. In this approach, the volute geometry were fixed with the original shape. The numerical results show that the blade profile with airfoil shape and small exit blade thickness increases the performance. The blade exit angle shows optimum angle within a varied range. The efficiency of the optimized exit angle was about $10\%$ higher than the base blade exit angle and the static pressure was about $28\%$ higher at the flow coefficient 0.22.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.4 no.4
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• pp.219-224
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• 1992

A numerical method using the truncated Fourier series is presented to predict the wave potential and water surface profile for two dimensional nonlinear standing waves. The unknown coefficients of the series are to be determined through the Newton solution of nonlinear simultaneous equations given by the governing equation and boundary conditions of the problem. In order to prove the effectiveness of the present method. an existing Stokes-like perturbation method is considered together, and a hydraulic experiment for measuring water surface profile and wave pressure is performed as well. The results are such that the present method can generally give exact solutions even for relatively big wave stiffness regardless of the water depth condition. It also demonstrates its validity by showing double humps in the crest of temporal wave pressure profile which normally appear in strongly nonlinear standing waves.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.5
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• pp.572-578
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• 1985

A composite gear with involute-circular are tooth profile and a tooth profile of the rack to cut this gear are theoretictically obtained. The composite gear has involute tooth profile in the vicinity of pitch point and has circular arc tooth profiles at addendum adn dedendum. The contact ratio(M$_{c}$), chordal tooth thickness (chordal tip tooth thickness S$_{t}$, chordal root tooth thickness S$_{t}$) of the composite gear are compared with those of involute gear. When module, number of teeth and pressure angle eqaul, S$_{t}$ of composite gear is much larger than that of involute gear. Under the same conditions, S/sib t/ and M$_{c}$ of composite gear become smaller than those of involute gear.lute gear.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.2
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• pp.198-204
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• 1987

In a new involute-circular arc tooth profile which is composed of an involute curve in the vicinity of pitch point, a circular arc in the addendum part, and a curve in the dedendum part which is generated by the circular arc profile of mating gear tooth profile, the tooth contact stress is calculated analytically and the root fillet stress is calculated by the finite element analysis. The root fillet stress and the Hertzian contact stress of composite tooth profile gear are decreased with increasing the pressure angle and with decreasing the radius of circular arc and unwound angle. Compared with the standard involute gear, the root fillet stress is decreased by 2-15% and the Hertizian contact stress is decreased by 6-24%.

• The Korean Journal of Pain
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• v.36 no.2
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• pp.173-183
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• 2023

Background: Understanding the stability of quantitative sensory tests (QSTs) over time is important to aid clinicians in selecting a battery of tests for assessing and monitoring patients. This study evaluated the short- and long-term reliability of selected QSTs. Methods: Twenty healthy women participated in three experimental sessions: Baseline, 2 weeks, and 6 months. Measurements included pressure pain thresholds (PPT) in the neck, upper back, and leg; Pressure-cuff pain tolerance around the upper-arm; conditioned pain modulation during a pressure-cuff stimulus; and referred pain following a suprathreshold pressure stimulation. Intraclass correlation coefficients (ICC) and minimum detectable change (MDC) were calculated. Results: Reliability for PPT was excellent for all sites at 2 weeks (ICC, 0.96-0.99; MDC, 22-55 kPa) and from good to excellent at 6 months (ICC, 0.88-0.95; MDC, 47-91 kPa). ICC for pressure-cuff pain tolerance indicated excellent reliability at both times (0.91-0.97). For conditioned pain modulation, reliability was moderate for all sites at 2 weeks (ICC, 0.57-0.74; MDC, 24%-35%), while it was moderate at the neck (ICC, 0.54; MDC, 27%) and poor at the upper back and leg at 6 months. ICC for referred pain areas was excellent at 2 weeks (0.90) and good at 6 months (0.86). Conclusions: PPT, pressure pain tolerance, and pressure-induced referred pain should be considered reliable procedures to assess the pain-sensory profile over time. In contrast, conditioned pain modulation was shown to be unstable. Future studies prospectively analyzing the pain-sensory profile will be able to better calculate appropriate sample sizes.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.603-607
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• 2002

Cavity pressure is a factor of what is occurring inside the mold and is used as one of the process parameters that control the overall injection molding cycle. The insight of cavity pressure is able to predict part quality and optimum process condition. In this paper, it is adapted ejector pin sensor to measure the cavity pressure and investigates the flow balance and the cavity pressure according to different runner thickness for adjusting the flow balance. Flow balance is very important to have not the poor results such as flash and warpage in the family mold. This paper predicted flow balance and cavity pressure using CAE analysis tool and compared with the test results. The results of analysis and test have a good agreement with the cavity pressure profile and flow pattern of the test.

• 유공압시스템학회:학술대회논문집
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• 2010.06a
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• pp.33-38
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• 2010

As for an oil hydraulic vane pump of vehicle hydraulic systems, the highest of planning technique required by the acquisition of optimum profile data which can be available to predict noises and vibrations. Pressure pulsation may result in considerable vibration and noise of pump component as well as cavitation in hydraulic system. The influences of the discharge pressure and rotating speed of the vane on the dynamic pressure in chamber surrounding a vane have been investigated. It is very important to predict pressure pulsation in vane pump. This paper presents analysis of technique of vane pump for automatic transmission. The predicted result using AMESim model were good agreement with the experimentally obtained results.

• Journal of the Korean Society of Safety
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• v.12 no.3
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• pp.52-59
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• 1997

Hill's anisotropy theory and isotropy theory under the deformed profile assumed two separate cases(that is circular and ellipitical) are applied to predict the plastic deformation characteristics of bulge, the strain and polar height under instability condition, using thin square diaphragms of stainless steel, mild steel, brass, copper and aluminum. In this study it was found that the pressure-polar height curves, and the polar height-the polar radius of curvature curve, under anisotropy theory and isotropy theory, assuming a circle profile, agree well with the experimental results, and the equivalent strains of the instability condition under anisotropy theory are better good agreement with the experimental results than those of the instability condition under isotropy theory. Beside, FLCo(plane Strain Intercept) obtained by Bethlehem FLC method and standard FLC method (modified) agree well with the experimental result.