• Speech Sciences
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• v.9 no.4
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• pp.113-130
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• 2002

Measurements were made of pressure rise time (PoRT), voice cessation time, flattened peak intraoral air pressure (Po), pressure static time (PoST), pressure-fall time and the duration of oral closure as four English speakers uttered isolated nonsense $V_{1}CV_{2}$ words containing /b/ and /p/ ($V_{1}=V_{2}$ and the V was /$\alpha$/), with stress on either $V_{1}orV_{2}$ alternately. The hypothesis tested was: The tense stop consonant. will be characterized either by a higher Po or a longer PoST, and/or by both against lax. Findings: (1) PoRT was significantly greater in /b/ than /p/, (2) the voiceless stop /p/ produced generally greater mean Po, averaged across five tokens, than its voiced counterpart /b/, but statistically insignificant, and (3) altogether, across stress, tokens and subjects, the difference in the calculated pressure static time (PoSTc), i.e., PoST + PoRT, between /p/ and /b/ was highly significant (p $\leq$ 0.003). Although further investigations remain to be taken, the results strongly supported the linguistic hypothesis of tense-lax distinction, with /b/ being lax and /p/ tense. Airflow resistance at the glottis and supraglottal air volume are assumed to be responsible for much of difference in PoRT between /p/ and /b/. The PoSTc reflecting, although indirectly, the respiratory efforts during the oral closure of a stop, was a convincing phonetic parameter of the consonantal tenseness based on respiratory efforts. The effects of stress on Po and PoSTc were inconsistent, and the shorter PoRT than consonantal constriction interval was always accompanied by Po and PoST.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.26 no.3
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• pp.121-125
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• 2016

The effect of temperature and pressure in the nitrogen ambient furnace on bulk micro defect (BMD) and denuded zone (Dz) is experimentally investigated. It is found that as pressure increases, Dz depth increases with a small decrease of BMD density in the range of temperature, $100{\sim}300^{\circ}C$. BMD density with hot isostatic pressure treatment (HIP) at temperature of $850^{\circ}C$ is higher than that without HIP while Dz depth is lower due to much higher BMD density. As the pressure increases, BMD density is increased and saturated to a critical value, and Dz depth increases even if BMD density is saturated. The concentration of nitrogen increases near the surface with increasing pressure, and the peak of the concentration moves closer to the surface. The nitrogen is gathered near the surface, and does not become in-diffusion to the bulk of the wafer. The silicon nitride layer near the surface prevents to inject the additional nitrogen into the bulk of the wafer across the layer. The nitrogen does not affect the formation of BMD. On the other hand, the oxygen is moved into the bulk of the wafer by increasing pressure. Dz depth from the surface is extended into the bulk because the nuclei of BMD move into the bulk of the wafer.

• Electrical & Electronic Materials
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• v.10 no.3
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• pp.217-225
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• 1997

In this study, the PVDF organic thin film was fabricated by the physical vapor deposition method to be dry-process. The distance of heat source and substrate was 5[cm] and the temperature of substrate was 30[.deg. C], when the pressure had reached 2.0 x 10$^{-5}$ [Torr], the temperature of heat source was reached to 285[.deg. C] to heat at 6-8[.deg. C/min] rate, the shutter was opened and deposition was started. TG-DTA(Thermogravimetric-Differential Thermal Analysis) spectrum of PVDF pellets showed that endothermic peak arose at 170[.deg. C] and exothermic peak at 524[.deg. C], but that of thin PVDF film showed that endothermic peak arose at 145[.deg. C] and exothermic peak at 443[.deg C]. The current density was increased linearly with increasing voltage but increased nonlinearly with higher electric field than 250[kV/cm] and activation energy was about 0.667[eV] at the temperature of 30-90[.deg. C].

• Journal of the Korea Institute of Building Construction
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• v.8 no.4
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• pp.115-121
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• 2008

The present study performed low-pressure steam curing with mortar specimens in order to examine the temperature profile and strength development of steam curing in high-strength specimens of 100MPa. In addition, as a basic research to utilize PC products, we examined the effects of curing temperature and time in steam curing cycle on strength development resulting from the hydration of cement within the range of high strength by changing four factors affecting the quality of PC displacement time, peak curing temperature, peak temperature duration, and ascending and descending gradient of temperature - in various patterns, and analyzed the optimal strength development characteristic based on the relation between temperature profile and strength development. With regard to the high-temperature curing characteristic of PC, we performed an experiment on the strength characteristic according to the temperature profile of high-strength mortar, and from the results of the experiment according to curing characteristic, displacement time, peak curing temperature, peak temperature duration, and ascending and descending gradient of temperature, we drew conclusions as follows.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.6
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• pp.114-120
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• 2021

This study is focused on the root mean square and peak-to-valley based on the injection conditions of the f-theta lens, one of the main components of laser printers and laser scanning systems. The f-theta lens of an aspherical plastic lens requires ultra-preaction. Injection molding is typically used for the mass production of aspherical plastic lenses. In the injection-molding method, the resin in the lens shape is filled with the resin after melting the plastic pellets at a constant temperature and then cooled. It is necessary to maintain a uniform injection molding system to produce high-quality lenses. These injection-molding systems are influenced by different factors, such as pressure, speed, temperature, mold, and cooling. It is possible to obtain a lens that exhibits the optical characteristics required to achieve harmony. We investigated the root mean square and peak-to-valley caused by variations in temperature, a critical parameter in the melting and cooling of plastic resins generated inside and outside the injection mold.

• Korean Journal of Applied Biomechanics
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• v.31 no.1
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• pp.64-71
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• 2021

Objective: This study investigated the different in isokinetic peak strength of the knee joint, and kinetics and kinematics in drop landing pattern of lower limb between the patellofemoral pain syndrome (PFPS) patients and normal. Method: 30 adult females were divided into the PFPS (age: 23.13±2.77 yrs; height: 160.97±3.79 cm, weight: 51.19±4.86 kg) and normal group (age: 22.80±2.54 yrs, height: 164.40±5.77 cm, weight: 56.14±8.16 kg), with 15 subjects in each group. To examine the knee isokinetic peak strength, kinematics and kinetics in peak vertical ground reaction force during drop landing. Results: The knee peak torque (Nm) and relative strength (%) were significantly weaker PFPS group than normal group. In addition, PFPS group had significantly greater hip flexion angle (°) than normal group. Moreover, normal group had significantly greater moment of hip abduction, hip internal rotation, and left ankle eversion than PFPS group, and PFPS group had significantly greater moment of knee internal rotation. Finally, there was significant differences between the groups at anteroposterior center of pressure. Conclusion: The PFPS patients had weakened knee strength, and which can result in an unstable landing pattern and cause of more stress in the knee joints despite to effort of reduce vertical ground reaction force.

• Journal of the Korea Fashion and Costume Design Association
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• v.21 no.4
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• pp.55-67
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• 2019

This study analyzed the fabric and product size of the burn patient's custom compression garment and measured the pressure applied by the garment to assess whether proper pressure is being delivered for treatment. The test clothes were presented to the market by body size and commissioned with the same design. The subjects selected four people close to the average body size of men in their 20s determined by 7th Size Korea. The experiment was conducted by wearing a compression suit, performing activities and measuring changes in the pressure of the garment according to changes in posture. The fabric used for the compressive clothing was not ruptured even at 216 kPa, the elasticity recovery rate was measured between 80.5 and 94.5%. The product dimensions of the experimental clothing varied by up to 8cm from brand to brand, requiring the standardization of compression clothing. The experiment showed that four types of compression suit varied in pressure, and the pressure range, excluding the gastric arm (17.9mmHg), was between 2.5-14.1mmHg, which failed to meet the level of pressurization for treatment purposes. The clothing pressure in the chest area dropped when performing movements rather than standing still. This was interpreted to be a result of reduced the adhesion of the compression suit during operation. The peak pressure (31.68mmHg) and the lowest pressure (2.2mmHg) was noted in the scapula, indicating that no pressure was being transmitted on the vertebrae. The pressure of the garment on the right shoulder blade was elevated in a supine position. Because much time is spent laying down, it is necessary for the pattern design to accommodate for the increased clothing pressure on the shoulder blades. Standardization of the level of pressurization for burn patient's custom-made pressure suits for each stage of treatment is urgently required.

• Journal of Korean Association for Spatial Structures
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• v.20 no.1
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• pp.49-59
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• 2020

This study investigates the wind pressure characteristics of elliptical plan retractable dome roof. Wind tunnel experiments were performed on spherical dome roofs with varying wall height-span ratios (0.1~0.5) and opening ratios (0%, 10%, 30% and 50%), similar to previous studies of cirular dome roofs. In previous study, wind pressure coefficients for open dome roofs have been proposed since there are no wind load criteria for open roofs. However, in the case of Eeliptical plan retractable dome roof, the wind pressure coefficient may be largely different due to the presence of the longitudinal direction and transverse direction. The analysis results leads to the exceeding of maximum and minimum wind pressure coefficients KBC2016 code.

• Safety and Health at Work
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• v.8 no.2
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• pp.212-219
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• 2017

Background: Low back pain (LBP) is a major problem for office workers. Individuals adopting poor postures during prolonged sitting have a considerably increased risk of experiencing LBP. This study aimed to investigate seat pressure distribution characteristics, i.e., average pressure, peak pressure ratio, frequency of postural shift, and body perceived discomfort (BPD), during 1 hour of sitting among office workers with and without chronic LBP. Methods: Forty-six participants (chronic LBP = 23, control = 23) typed a standardized text passage at a computer work station for an hour. A seat pressure mat device was used to collect the seat pressure distribution data. Body discomfort was assessed using the Body Perceived Discomfort scale. Results: Office workers with chronic LBP sat significantly more asymmetrically than their healthy counterparts. During 1-hour sitting, all workers appeared to assume slumped sitting postures after 20 minutes of sitting. Healthy workers had significantly more frequent postural shifts than chronic LBP workers during prolonged sitting. Conclusion: Different sitting characteristics between healthy and chronic LBP participants during 1 hour of sitting were found, including symmetry of sitting posture and frequency of postural shift. Further research should examine the roles of these sitting characteristics on the development of LBP.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.392-395
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• 2006

This paper presents the experimental results at slamming phenomenon. The air pressure cylinder was used to ensure repeatability of the impact. The results showed that the adopted experimental technique was very excellent in terms of repeatability when is compared to that of the free drop tests. The pressure time histories, magnitude of peak pressure and the behavior of jet spray were obtained. The flat specimen was tested for various incident angles. To estimate the incident speed of the specimen high speed camera was used. The high speed camera was also useful tool in understanding the behavior.