• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.07b
• /
• pp.830-833
• /
• 2003

This paper describes the fabrication and characteristics of 3C-SiCOI sotctures by SDB and etch-back technology for high-temperature MEMS applications. In this work, insulator layers were formed on a heteroepitaxial 3C-SiC film grown on a Si(001) wafer by thermal wet oxidation and PECVD process, successively. The pre-bonding of two polished PECVD oxide layers made the surface activation in HF and bonded under applied pressure. The wafer bonding characteristics were evaluated by the effect of HF concentration used in the surface treatment on the roughness of the oxide and pre-bonding strength. Hydrophilic character of the oxidized 3C-SiC film surface was investigated by ATR-FTIR. The strength of the bond was measured by tensile strengthmeter. The bonded interface was also analyzed by SEM. The properties of fabricated 3C-SiCOI structures using etch-back technology in TMAH solution were analyzed by XRD and SEM. These results indicate that the 3C-SiCOI structure will offers significant advantages in the high-temperature MEMS applications.

• Journal of the korean Society of Automotive Engineers
• /
• v.12 no.5
• /
• pp.76-84
• /
• 1990

To study diesel fuel spray behavior, an experimental study was undertaken to investigate injection characteristics in vary ing back pressure and atomization mechanism in a non-evaporating diesel spray. Generally, injection characteristics is the curve of fuel flow plotted against time. The area under this curve is equal to the total quantity of fuel discharged for one injection. The method that measures rate of injection is long tube-type fuel rate indicator. Diesel spray injected into a quiescent gaseous environment under high pressure is observed by taking high speed camera by the focused shadow photographs. The results show that, at the start of injection, as the injected fuel rushes into the quiescent atmosphere the spray angle becomes large. Finally the spray stabilizes at a constant cone angle. Spray penetration length increases with the injection pressure.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.7 no.9
• /
• pp.56-62
• /
• 1999

The disintegration of transient diesel spray in early was investigated at different opening pressure and chamber pressure by measns of shadowgraph method using nanolite and still camera. Diesel spary was injected into the spray chamber which was charged with high pressure nitrogen gas. Atthe begining of injection, a liquid column that was almost the same diameter as the nozzle hole was observed . Spray tip penetration and spray angle were always increased with an increase in opening pressure.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.17 no.2
• /
• pp.197-206
• /
• 1993

We studied relation between the clothing pressure applied by foundations(waist nipper, girdle, body suit) on the waist of bodies and muscular activity, feeling of tightness. The main results were summerized as follows ; 1. Clothing pressure applied by foundations was high in order of girdle>waist nipper>body suit, also clothing pressure was higher back than front and side, sitting on the chair than standing posture, ventral flection than repose. Individual differences, even if size of body was equal, were shown in clothing pressure applied by foundations with subcutaneous fat's amount in measuring region. 2. The muscular activity of rectus abdominis than obliquus externus abdominis was more affected by foundations in all kinds of postures and motions. Amplitude of electromyogram was high sitting on the chair than standing posture, but there was little difference with motion variation. The wearing girdle strongly affected on the muscular activities of rectus abdominis and obliquus externus abdominis as compared with waist nipper and body suit. 3. The value for feeling of tightness by wearing waist nipper was higher than girdle and body suit. Also the case when sitting on the chair and ventral flection, the value for feeling of tightness was high. When the foundations were on the body, most tightened on the region of the body was anterior abdominal region.

• Applied Science and Convergence Technology
• /
• v.23 no.4
• /
• pp.169-178
• /
• 2014

Fluid model based numerical analysis is done to simulate a low damage etch back system for 20 nm scale semiconductor fabrication. Etch back should be done conformally with very high material selectivity. One possible mechanism is three steps: reactive radical generation, adsorption and thermal desorption. In this study, plasma generation and transport steps are analyzed by a commercial plasma modeling software package, CFD-ACE+. Ar + $CF_4$ ICP was used as a model and the effect of reactive gas inlet position was investigated in 2D and 3D. At 200~300 mTorr of gas pressure, separated gas inlet scheme is analyzed to work well and generated higher density of F and $F_2$ radicals in the lower chamber region while suppressing ions reach to the wafer by a double layer conducting barrier.

• Fashion & Textile Research Journal
• /
• v.2 no.5
• /
• pp.430-436
• /
• 2000

The purpose of the study was to obtain the basic data on the self-adjusting ability of the support panty stockings. Ten healthy women in the twenties were selected as subjects and clothing pressure of 9 support panty stockings made of single covered yarn (SCY) and double covered yarn (DCY) were measured under the standard environmental condition for the study. Data was analysed statistically according to body postures, sides, and parks. The results were as follows: Clothing pressure according to body posture was order of 'sitting-on-a-chair', 'stepping-up-a-stair', and 'standing'. High clothing pressure was obtained in the parts of calf ($9.4gf/cm^2$) in 'standing' and knee (9.7 and $16.5gf/cm^2$) in both 'stepping-up-a-stair' and 'sitting-on-a-chair', respectively. The order of clothing pressure with body sides was 'front', 'side', and 'back'. The highest clothing pressure was knee ($18.8gf/cm^2$) on the front, thigh ($8.8gf/cm^2$) on the side, and calf ($6.4gf/cm^2$) on the back. Clothing pressure of DCY at abdomen and knee was a little higher than those of SCY 3. In terms of material structure variation, clothing pressure of thigh, calf and ankle with SCY was a little higher than those with DCY, while clothing pressure of abdomen and knee with DCY was a little higher than those with SCY.

• Journal of Welding and Joining
• /
• v.29 no.4
• /
• pp.80-84
• /
• 2011

In the 5xxx series Al-Mg alloy, magnesium addition can increase the strength of aluminum alloy by solid solution strengthening but it has a relatively low melting and boiling temperature. During full -penetration laser welding of the Al-Mg alloys, its low boiling point and high vapor pressure brings about the spiky humping bead on the bottom side. Under back-side shielding, the spiking of back bead can be reduced but it restraints the process flexibility. In this study, a square pulse waveform modulation was employed to stabilize keyhole and back bead surface without back-side shielding. By using an experimental design, the bead shapes were evaluated for various process parameters such as the focal position, welding velocity and waveform parameters and the smooth back bead shape could be achieved.

• Biomedical Science Letters
• /
• v.19 no.1
• /
• pp.55-60
• /
• 2013

This study was to know the effects of massage on the back region in order to reduce stress in middle age women. To investigate the effects of massage to the stress levels of middle aged women, we evaluated blood pressure (BP), heart rate variability (HRV), and ultrasonography before and after back massage. The blood pressure after massage was reduced when compared to that of pre-massage. The HRV spectrum analysis was used Frequency domain analysis such as Mean HRV, normalized low frequency (norm LF), norm high frequency (norm HF), and LF/HF ratio. Post-massage BP tended to be low, but not statistical significant. After Massage, the Mean HRV, norm LF, and LF/HF ratio were significantly reduced, while norm HF was significantly increased as compared with pre-massage. The muscle layer and fat layer were significantly diminished by massage. The study was suggested that massage may be an effective treatment for relief of stress.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.04a
• /
• pp.132-135
• /
• 2011

A technology for buzz margin determination is suggested to obtain stable shock structure and high compression efficiency of supersonic intake. By using the shock equilibrium equation of supersonic intake, sensitivity equation of terminal shock position for free stream and back pressure is induced and disturbances are quantified through statistical approach. Numerical results show that the sensitivity of shock position for disturbances is proportional to Mach number and the back pressure is dominant for variance of terminal shock position.

• Fashion & Textile Research Journal
• /
• v.21 no.1
• /
• pp.67-74
• /
• 2019

This study aims to investigate the relation between pressure, 3D length change, and subjective pressure sensation in sports brassieres. Seven Korean women in their 20s and 30s were chosen as subjects. In the experiment, the subjects evaluated four types of sports brassieres wherein the lower band was changed. The results of the study were as follows. The pressure according to the measurement position was lower at the front part than at the side and back parts (p<.05), and there was no difference in the pressure according to the brassiere type. It was observed that brassiere C, which had the higher extension band, was elongated more than the other brassieres when worn. In the case of brassiere B, which had a slit in the front center, it was observed that the 3D length of the front part changed very little as the slit spreads, and the back part stretched in a manner similar to those of the other brassieres. Subjective pressure sensation was statistically different only at the front and the side of the lower band. Brassiere B(with a silt) demonstrated the least subjective pressure sensation; the pressure sensation was high when wearing brassieres A and D (p<.05). Brassieres B and C were also preferred for overall comfort. In conclusion, it was observed that the substitution of material and morphological transformation affect subjective sensation.