• Transactions on Electrical and Electronic Materials
• /
• v.18 no.1
• /
• pp.51-54
• /
• 2017

TFTs (thin film transistors) were fabricated using a-SIZO (amorphous silicon-indium-zinc-oxide) channel by RF (radio frequency) magnetron sputtering at room temperature. We report the influence of various channel thickness on the electrical performances of a-SIZO TFTs and their stability, using TS (temperature stress) and NBTS (negative bias temperature stress). Channel thickness was controlled by changing the deposition time. As the channel thickness increased, the threshold voltage ($V_{TH}$) of a-SIZO changed to the negative direction, from 1.3 to -2.4 V. This is mainly due to the increase of carrier concentration. During TS and NBTS, the threshold voltage shift (${\Delta}V_{TH}$) increased steadily, with increasing channel thickness. These results can be explained by the total trap density ($N_T$) increase due to the increase of bulk trap density ($N_{Bulk}$) in a-SIZO channel layer.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 1996.06c
• /
• pp.238-246
• /
• 1996

When the important structures or components of agricultural machinery are designed, the full-filed methods of stress analysis can provide enough information in order to obtain lighter weight and prevent failure. The photoelasticity has been applicated to solve many practical engineering problems. The coating method provides full-field information, enabling the engineers to determine the complete distribution of surface strains and directly highlighting severely strained areas, especially for the welded frames of agricultural machinery. A combined method of model and prototype for strain analysis of excavator has been successfully applied to improve design. A measuring and recording system controlled by micro-computer and application software for dynamic event was studied. It can be widely used in structural failure analysis under cyclical loading . Typical application concerned stress field of crack tip and failure analysis of some mechanical structures are introduced are in roduced briefly in this paper.

• Transactions of Materials Processing
• /
• v.5 no.4
• /
• pp.327-336
• /
• 1996

The effect of dynamic strain aging on high temperature deformation behaviour of the A-Mg alloy was investigated by strain rate change tests and stress relaxation tests between 20$0^{\circ}C$and 50$0^{\circ}C$. Yield point, short stress transient and periodic discontinuities on the stress-strain curve were considered as an evidence of the effect of dynamic strain aging. With this criterion two distinct strain rate-temperature regimes could be manifested. Dynamic strain aging was considered to be effective in the high temperature-low strain rate regime, whereas dynamic recovery was a dominant deformation mechanism in the low temperature-high strain rate regime. It was found that dynamic strain aging in the high temperature deformation was governed by the mechcanism of diffusion-controlled, viscous dislocation movement.

• Proceedings of the KIEE Conference
• /
• 1994.07a
• /
• pp.72-75
• /
• 1994

In this paper, a novel method to figure out the relative residual stress distribution along the depth of silicon diaphragms is presented Cantilevers with various thickness are fabricated by the time controlled etching method using EPW as an etchant. The boron concentration along the depth of the cantilevers is obtained by the TSUPREM IV simulation, and the etching time to get the proper thickness is calculated. By measuring deflections of the p+ silicon cantilevers the stress profile along the depth of diaphragm is calculated. The obtained stress profile is reasonable and useful to expect the deflection of cantilevers and the buckling of diaphragms.

• The Journal of Korean Physical Therapy
• /
• v.26 no.6
• /
• pp.391-397
• /
• 2014

Purpose: The aim of this study was to investigate the effects of manual lymph drainage (MLD) on the activity of sympathetic nervous system, anxiety, pain and pressure pain threshold in subjects with psychological stress. Methods: Twenty-nine subjects with psychological stress were randomly assigned to experimental (MLD) and control (rest) groups. This study was performed as a controlled, randomized study using spectral analysis of electrocardiographic (ECG) activities, the State-Trait Anxiety Inventory (STAI), Visual Analogue Scale (VAS) and Pressure Pain Threshold (PPT). Results: Heart rate variability differed significantly between the experimental and control groups (p<0.05). Anxiety and pain showed positive change in both group but it were not showed statically differences. The pressure pain threshold in the upper trapezius muscle was increased in the experimental group (p<0.05). Conclusion: These findings indicate that the application of MLD was effective in reducing the activity of the sympathetic nervous system, anxiety, pain, and increasing the PPT.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 2004.11a
• /
• pp.18-34
• /
• 2004

This paper will review data obtained primarily from our preclinical investigations that show that exposure to stress has a significant impact on drug taking. Stress increases reward associated with psychomotor stimulants, possibly through a process similar to sensitization, and a growing clinical literature indicates that there is also a link between substance abuse and stress in human addicts. One explanation for the high concordance between stress-related disorders and drug addiction is the self-medication hypothesis, which suggests that a dually-diagnosed person often uses the abused substance to cope with tension associated with life stressors or to relieve symptoms of anxiety and depression resulting from a traumatic event. However, another characteristic of drug self-administration is that drug delivery and its subsequent effects on the HPA axis are under the direct control of the individual. This controlled activation of the HPA axis may result in the production of an internal state of arousal or stimulation that is actually sought by the individual (i.e., the sensation-seeking hypothesis). During abstinence, however, exposure to stressors or drug-associated cues can stimulate the HP A axis to remind the individual about the effects of the abused substance, thus producing craving and promoting relapse. Stress reduction, either alone or in combination with pharmacotherapies targeting the HPA axis may prove beneficial in reducing cravings and promoting abstinence in individuals seeking treatment for addiction. Of primary importance is to reduce the impact of cocaine-associated environmental stimuli on the HPA axis so that they no longer function as triggers for relapse.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2006.03a
• /
• pp.137-146
• /
• 2006

Shear wave velocity of uncemented soil can be expressed as the function of effective stresses when capillary phenomenons are negligible. However, the terms of effective stresses are divided to the direction of wave propagation and polarization because stress states are generally anisotropy. The shear wave velocities are affected by parameters and exponents that are experimentally determined. The exponents are controlled contact effects of particulate materials(sizes, shapes, and structures of particles) and the parameters are changed contact behaviors between particles, material properties of particles, and type of packing(i.e., void ratio and coordination number). In this study, consolidation tests are performed by using clay, mica and sand specimens. Shear wave velocities are measured during consolidation tests to investigate the stress-induced and inherent anisotropies through bender elements. Results show the shear wave velocities depends on the stress-induced anisotropy for round particles. Furthermore the shear wave velocity is dependent on particle alignment under the constant effective stress. This study suggests that the shear wave velocity and the shear modulus should be carefully calculated and used for the design and construction of geotechnical structures.

• International Journal of Contents
• /
• v.5 no.4
• /
• pp.44-50
• /
• 2009

The purpose of this research was to measure the effect of a gestalt group meditation therapy intervention program on occupational stress and anxiety in working women aged 30 to 49 in Korea. Scientific methods were employed to test a gestalt group meditation therapy intervention program as treatment for working women in 30-40s to reduce their level of occupational stress and anxiety. The study involved 18 volunteer subjects ages of 30 to 49 years, randomly divided into two groups: (1) gestalt group meditation therapy intervention program, and (2) no program. Both groups completed a pre-test and a post-test of occupational stress scale and trait anxiety inventory. The outcome data was analyzed as qual1litative information using the SPSSPC+ computer program. Mann-Whitney U test was used to analyze the result in order to verify the sameness between experienced group and controlled group of pre-test scores within the groups. Also U-test comparisons were used to analyze the treatment effects. The results of this investigation indicated that (1) occupational stress scores decrease after gestalt group meditation therapy intervention program on the treatment group, and (2) trait-anxiety scores decrease after gestalt group meditation therapy intervention program on the treatment group. In summary, the gestalt group meditation therapy intervention program for career women, aged 30 to 49, in Korea could reduce the subjects' occupational stress and anxiety.

• Journal of the Korean institute of surface engineering
• /
• v.37 no.4
• /
• pp.226-233
• /
• 2004

The residual stresses on the surfaces of low carbon 12Cr steels used as a nuclear steam turbine blade material have been studied by controlling the flame hardening surface treatments. The temperature cycles on the surfaces of 12Cr steel were controlled precisely as a function of both the surface temperature and cooling rate. The final residual stress state generated by flame hardening was dominated by two opposite competitive contributions; one is tensile stress due to phase transformation and the other is compressive stress due to thermal contraction on cooling. The optimum processing temperatures required for the desirable residual stress and hardness were in the range of $850^{\circ}C$ to $960^{\circ}C$ on the basis of the specification of GE power engineering. It was also observed that the high residual tensile stress generated by flame hardening induced the cracks on the surfaces, especially across the prior austenite grain boundaries, and the material failure virtually, which might limit practical use of the surface engineered parts by flame hardening.

• Journal of Korean Academy of Fundamentals of Nursing
• /
• v.12 no.3
• /
• pp.389-394
• /
• 2005

Purpose: This study was done to examine the relationship between life stress and depression, and the effect of social support of 100 Koreans living in the Phillippines. Theoretically social support is considered to mediate the relationship between lift stress and depression. Method: Data were collected from April 1 to May 30, 2002 and analysed using SAS. The first, two hypotheses were tested using Gamma, a measure of association for ordinal variables. Partial gamma was used to test the third hypothesis. Patterns of elaboration described by Babbie(1986) were selected to interpret the relationship of the three variables in the analysis. Results: 1) There was a positive relationship between life stress and depression(Gamma=.45, p=.017), and a inverse relationship between social support and depression(Gamma=-.561, p=.002). Thus the first, two hypotheses were supported. 2) When social support was controlled, the relationship between life stress and depression increased under the condition of low social support but with high social support, the relationship decreased. Conclusion: It can be interpreted that life stress is positively related to depression under the condition of low social support, however this relationship may be reversed with high social support.