• Journal of Surface Science and Engineering
• /
• v.32 no.2
• /
• pp.144-156
• /
• 1999

Thermal Barrier Coating with Functional Gradient Materials (FGM-TBC) can play an important role to protect the parts from harmful environments in high temperatures such as oxidation, corrosion, and wear and to improve the efficiency of aircraft engine by lowering the surface temperature on turbine blade. FGM-TBC can increase the life spans of product and improve the operating properties. Therfore, in this study the evaluations of mechanical and thermal properties of FGM-TBC such as fatigue, oxidation and wear-resistance at high temperatures have been conducted. The samples of both the TBC with 2, 3, 5 layers (YSZ/NiCrAlY) to be produced by Air Plasma Spray method (APS) and the bulk TBC with 6 layers to be produced by Plasma Assisted Sintering method (PAS) were used. Furthermore, residual stress, bond strength, and thermal conductivity were evaluated. The average thickness of the APS was 500$\mu\textrm{m}$ to 600$\mu\textrm{m}$ and the average thickness of the PAS was 3mm. The hardness number of the top layer of APS was 750 Hv to 810Hv and that of PAS was 950 Hv to 1440Hv. The $ZrO_2$ coating layer of APS was composed of tetragonal structure after spraying as the result of XRD analysis. As shown in the results of the high temperature wear test, the 3 layer coating of APS had the best wear resistance at $800^{\circ}C$ and the 5 layer coating of APS had the best wear resistance at $600^{\circ}C$. But, these coatings had the tendency of the low-temperature softening at $300^{\circ}C$. The main mechanism of wear was the adhesive wear and the friction coefficient of coatings was increased as increasing the test temperatures. A s results of thermal conductivity test, the ${\Delta}T$ of the APS coating was increased as number of layer and the range of thermal conductivity of the PAS was $800^{\circ}C$ to $1000^{\circ}C$.

• Journal of Korean Medicine for Obesity Research
• /
• v.15 no.2
• /
• pp.153-161
• /
• 2015

Gamrosu is a modified fasting therapy beverage (431 kcal/d). A retrospective observational study was conducted to investigate the detoxification feasibility of Gamrosu. Three cases were reviewed which participants have finished the fasting with Garmrosu for 10 consecutive days. Detoxification profiles of Gamrosu were reviewed at pre- and post-fasting sessions. Post-Gamrosu session, -6.3% of average weight, -6.5% of average body fat mass and -6.6% of average muscle mass were reduced with the nutrition indices being improved. The inflammation indices showed the significant diminished profiles. Liver/kidney functions and the standard of electrolytes were maintained within normal range in stable manners, however, marginal elevation of total bilirubin and mild ketoacidosis were observed. The indices of oxidative stress decreased and those of antioxidative activity increased. The fatigue scale scores indicated lower scores except insomnia symptom. Taken together, detoxification profiles of Gamrosu were sufficiently feasible and the observed findings should be considered for further clinical studies.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.4 no.2
• /
• pp.133-142
• /
• 1984

With the weld-joined compact tension specimens compared with each other, that is, transverse and lengthwise about the crack propagation direction, high and low in the input heat level, same as and lower than the base metal in the strength of weld material, the fatigue test were performed. With these data, the log-log curves between the fatigue crack propagation rate ${\frac{da}{dN}}$ and the transition range of the stress intensity factor ${\Delta}K$ ahead the crack tip were drawed. These curves were compared and estimated among each compared specimens, among each zones, that is, the base metal, the heat-affected metal and the weld-mixed metal, and between this study and the past studies. Basically, Little difference in the slope of the $da/dN-{\Delta}K$ relation was showed in all the welded directions, all the input heat levels and all the zones. But, First, to comparison with in the past studies about the base metals, it was showed that da/dN started in the much later rate, increased faster and stoped in the little faster rate. Second, it was showed that, near the time the crack's going from the heat-affected zone to the weld-mixed metal da/dN decreased a little for a while. Third, in the lengthwise weld compared with the transverse weld, in the high input heat weld compared with the low input heat weld in the case used the weld material of the same strength as the base metal, in the opposite case in the case used the one of the lower strength than the base metal, in the case used the weld material of the same strength as compared with the lower strength than the base metal beside the high input heat and the lengthwise weld, it was showed that the crack occured earlier in lower ${\Delta}K$ and later da/dN, the curves went with the same slope. Forth, in the lengthwise weld compared with the transverse weld in the low input heat weld, in the low input heat weld compared with the high input heat weld, it was showed that da/dN went with the lower level.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.7 no.1
• /
• pp.93-101
• /
• 1987

Residual stresses have remained around welding areas of a steel structure member after welding operation. The major causes to occur these residual stresses are the local heat due to a welding, the heat stresses due to a irregular and rapid cooling condition, the material and rigidity of a steel structure. Ultimatly, these residual stresses have been known to decrease a brittle fracture strength, a fatigue strength, a buckling strength, dynamic properties, and the corrosion resistance of the material. This paper deals with the residual stresses on a steel structure member through experimental studies. SWS 58 plates were welded by the method of X-groove type. These plates were layed on the heat treatment at four different temperatures; $350^{\circ}C$, $500^{\circ}C$, $650^{\circ}C$ and $800^{\circ}C$. The resulting residual Stresses were measured by hole drilling method, and the followings were obtained. The residual stresses on the vicinity of a welding point were relieved most effectively at the temperature of $650^{\circ}C$, and these stresses relieved completly when the ratio of a hole diamerter to a hole depth became unity. Hardness test shows that the higher value of hardness at the heat affected zone dropped to belower as the temperature went up from $350^{\circ}C$ to $800^{\circ}C$. The Welding input heats have not influenced the magnitude of residual stresses at the input heat range between above and below one forth than standard.

• Women's Health Nursing
• /
• v.5 no.1
• /
• pp.146-165
• /
• 1999

The purpose of this paper was to identify the performance of health promoting lifestyles and health perception over 18 years old women living Wonju city so that the results will be based for setting up women's health nursing center. The subjects were 1080 women selected by stratified and purposive sampling. The data were collected by self reporting questionnaire and interview from May to June, 1998. Data were analyzed by SPSS win program. The results were as follows : 1. The range of age was 18-84 years, The proportion according to women's lifecycle was premarital group 20.0%, delivery and rearing group 49.9%, over middle aged-elderly group 29.8%. 2. The mean menarchial age was 15.2 and menopausal age was 48. Mean frequenices of pregnancy is 2.4 and artificical abortion rate is 36.4%. Primary cause of abortion was unwanted babies 42.8%. The practice rate of family planning was 79.4% and permanent sterilization rate was 37.6%. 3. Fatigue was predominated problem in target population. Depression and headache was predominated in premarital group, headache and nervous felling in delivery and rearing group, arthritis and loss of memory in over middle aged-elderly group. 4. Only 13.7% of the target population make some efforts for their health in compare to 85.9% have attention for their health. Perception of unhealthy rate was 9.1% in premarital group, 24.8% in delivery and rearing group, 30.1% in middle aged-elderly group. 5. The average score of the HPLP(Health Promoting Lifestyle Profile) was 2.41. The variable with the highest degree of performance was interpersonal relationship, whereas the one with the lowest degree was the professional health maintenance. The significant difference was found in HPLP according to age, residential area, marital status, educational level, income level. 6. Majority(95.1%) of the target population agreed on necessity for women's health nursing center. Proper location area was presented to women's center and public health center. The priority for health education program was proper diet, family health, stress management, and exercise. In conclusion, we should prepare the education program for women's health according to women's lifecycle, because health perception, HPLP, and education program needed was differentiated in women's lifecycle. Also we suggest that women's health nursing center based community was needed for proper management of women's health.