• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.3
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• pp.401-407
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• 2012

The recent manufacturing process in the thin wafers and flat panel necessitate new approaches to reduce handling fragile and surface-sensitive damage of components. This paper presents a new pneumatic levitation for non-contact handling of parts and substrates. This levitation can achieve non-contact handling by blowing air into an air pressure pick-up head with radial passages to generate a negative pressure region. Negative pressure is caused by the radial air flow by nozzle throat and through holes connecting to the bottom region. The numerical analysis deals with the levitational motion with different design factors. The dynamic motion is examined in terms of force balance(dynamic equilibrium) occurring to the flow field between two objects. The stable equilibrium position and the safe separation distance are determined by analyzing the local pressure distribution in the fluid motion. They make considerable design factors consisting the air pressure pick-up head. As a result, in case that the safe separation distance is beyond 0.7mm, the proposed pick-up head can levitate stably at the equilibrium position. Furthermore, it can provide little effect of torque, and obtain more wide picking region according to the head size.

• Journal of Sensor Science and Technology
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• v.16 no.6
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• pp.413-418
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• 2007

Uroflowmetry is of great convenience to diagnose benign prostate hypertrophy common in aged men. The urinary flow rate is obtained by weight measurement using load cell, however, sensitive to impact noise. An alternative technique was recently proposed to measure hydraulic pressure instead of weight and demonstrated to introduce significantly reduced noise. In this paper, we described the measured diagnostic parameters between the weight and pressure measuring techniques in 10 normal men. The weight and pressure signals were simultaneously acquired during urination, converted into urine volumes, then differentiated to obtain flow rate signals, which showed very similar waveforms. Diagnostic parameters evaluated by pressure measuring technique were well correlated with the standard weight measuring technique (correlation coefficient > 0.99). Therefore, the new uroflowmetry based on hydraulic pressure measurement can provide accurate diagnostic parameters, which would be clinically valid.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.5
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• pp.637-649
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• 1997

Effects of cone angle, pressure-hole orientation and Reynolds number on the five-hole probe calibration have been investigated for eight large-scale conical five-hole probes, which have either perpendicular pressure holes or forward-facing pressure holes for the cone angles of 45 deg, 60 deg, 75 deg and 90.deg. Pitch and yaw angles are changed from -40 deg to +40 deg with an interval of 5 deg, respectively, when the probe Reynolds numbers are 1.77*10$^{4}$, 3.53*10$^{4}$ and 7.06*10$^{4}$. The result shows that larger cone angle results in more sensitive changes in the calibration coefficients. In the case that the cone angle is 45 deg, the pitch-angle and yaw-angle coefficients of the five-hole probe with the perpendicular pressure holes show a very different trend compared with those of the five-hole probe with the forward-facing pressure holes. On the other hand, when the cone angle is more than 60 deg, each calibration coefficient is nearly independent of the pressure-hole orientation. Additionally, the effects of the Reynolds number on the calibration coefficients are also reported in detail.

• The KSFM Journal of Fluid Machinery
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• v.17 no.5
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• pp.5-10
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• 2014

In this paper, the experimental study was carried to investigate the effect of angle of the anti-vortex holes on the film cooling effectiveness on a flat plate. The pressure sensitive paint technique was applied to measure the film cooling effectiveness. Two anti-vortex hole angles of $0^{\circ}$ and $15^{\circ}$ with respect to the primary hole were considered, and the simple cylindrical hole case was also tested. The blowing ratio based on the cylindrical hole was 0.5 and the same flow rate was kept for all anti-vortex hole cases. Results showed that the film cooling effectiveness for the anti-vortex hole cases were much higher than that of the cylindrical case. Among the anti-vortex hole cases, $15^{\circ}$ angle anti-vortex hole case showed higher film cooling effectiveness than that by the $0^{\circ}$ angle anti-vortex hole case.

• The Journal of the Korean dental association
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• v.50 no.1
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• pp.22-30
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• 2012

The methods for the occlusal force measurement have long been developed. The occlusal analyzing equipment utilizing the pressure-sensitive film (Prescale) is useful for the assessment and comparison among large group of patients. On the other hand, the apparatus which uses the grid-based sensor sheet (T-scan) can be a useful assistant for acquiring the well-balanced occlusion. The device that can process the electrical input from the strain gauge which is attached to the tooth surface can collect the dynamic data of actual masticatory force. This device has been developed for the measurement of actual mastication with the food bolus and it can be a useful method for the comparison before and after the restorative treatment. Occlusal force measurement can be applied for the analysis of therapeutic action, diagnosis of crack- tooth syndrome, temporomandibul ar disease, and idiopathic implant loosening.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.876-879
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• 2004

The buried fiber optic cable as a distributed intrusion sensor for detecting and locating intruders along the long perimeters is proposed. Phase changes resulting from either the pressure of the intruder on the ground immediately above the buried fiber or from seismic disturbances in the vicinity are sensed by a phase-sensitive optical time-domain reflectometer. Light pulses from a Er:fiber cw laser with a narrow, <3kHz-range, spectral width and a frequency drift of < 1 MHz/min are injected into one end of the fiber, and the backscattered light from the fiber is monitored with a photodetector. Results of preliminary studies, measurement of phase changes produced by pressure and seismic disturbances in buried fiber optic cables and simulation of ${\varphi}-OTDR$ response over long fiber paths, to establish the feasibility of the concept are described. The field experiments indicate adequate phase changes, more than 1t-rad, are produced by intruders on foot and vehicle for burial depths in the 0.2 m to 1 m range in sand, clay and fine gravel soils. The simulations predict a range of 10 km with 35 m range resolution and 30 km with 90 m range resolution. This technology could in a cost-effective manner provide enhanced perimeter security.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.301.1-301.1
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• 2016

We report an ultraclean, cost-effective, and easily scalable method of transferring and patterning large-area graphene using pressure sensitive adhesive films (PSAFs) at room temperature. This simple transfer is enabled by the difference in wettability and adhesion energy of graphene with respect to PSAF and a target substrate. The PSAF transferred graphene is found to be free from residues, and shows excellent charge carrier mobility as high as ${\sim}17,700cm^2/V{\cdot}s$ with less doping compared to the graphene transferred by thermal release tape (TRT) or poly(methyl methacrylate) (PMMA) as well as good uniformity over large areas. In addition, the sheet resistance of graphene transferred by recycled PSAF does not change considerably up to 4 times, which would be advantageous for more cost-effective and environmentally friendly production of large-area graphene films for practical applications.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.6 no.1
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• pp.43-49
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• 2010

The piping failure probability of the reactor coolant system in Kori unit 1 was evaluated considering stress corrosion cracking. The P-PIE program (Probabilistic Piping Integrity Evaluation Program) developed in this study was used in the analysis. The effect of some variables such as oxygen concentration during start up and steady state operation, and operating temperature, which are related with stress corrosion cracking, on the piping failure probabilities was investigated. The effects of leak detection capability, the size of big leak, piping loops, and reactor types on the piping failure probability were also investigated. The results show that (1) LOCA (loss of coolant accident) probability of Kori unit 1 is extremely low, (2) leak probability is sensitive to oxygen concentration during steady state operation and operating temperature, while not sensitive to the oxygen concentration during start up, and (3) the piping thickness and operating temperature play important roles in the leak probabilities of the cold leg in 4 reactor types having same inner diameter.

• Journal of Pharmaceutical Investigation
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• v.41 no.1
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• pp.1-7
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• 2011

The effects of different formulation variables including pressure sensitive adhesive (PSA), permeation enhancer, thickness of the matrix and loading amount of drug on the transdermal absorption of galantamine were investigated across the hairless mouse skin. The permeation profile of galantamine was different depending on the types of PSA, loading amount of drug, thickness of the matrix and type of enhancer used. Highest flux of galantamine was obtained from acrylic PSA but crystals were formed in the patch within 72 h. Among the PSAs screened, crystal formation was not observed only in the patches formulated in Styrene Butadiene Styrene (SBS) matrix. Permeation rate increased linearly as the concentration of galantamine in SBS matrix increased from 2.5 to 15% w/w. Among the enhancers screened, Brij$^{(R)}$ 30 provided highest flux of galantamine. Matrix thickness of 80 ${\mu}m$ was optimum for maintaining adhesiveness as well as consistently delivering galantamine for longer period of time.

• Korean Journal of Community Nutrition
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• v.1 no.1
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• pp.79-88
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• 1996

This study was conducted to assess nutritional status of the elderly from low-income urban area and to investigate environmental and health risk factors that may influence to nutrient intakes. One hindered eighty three(males 53, females 130) healthy homestaying subjects aged over 65 years in Seoul were assessed with anthropometric measurements and dietary intake in August, 1994. HT and BW for females were decreased with aging. The proportion of hypertension was 36% with indite of $SBP{\;}(SBP{\;}{\gg}{\;}160mmHg)$ and 52% with indice of DBP $(DBP{\;}\gg{\;}97mmHg)$. Distribution of BMI, OR and PIBW indicated that BMI was more sensitive for identifying underweight whereas PIBW was more sensitive for identifying overweight. for group aged over 75, males had significantly lower intake of energy, protein, fat, calcium, iron, vitamin A and $\beta$ carotene compared to the group aged 67~74, while females had lower intake of calcium and vitamin A. Elderly group with smoking, less familly size and living alone had lower nutrient intakes. Blood pressure in the elderly subjects did not influence to nutrient intakes, except elderly with normal blood pressure were taking increased amount of thiamin and niacin.