• Journal of Powder Materials
• /
• v.24 no.2
• /
• pp.133-140
• /
• 2017

This study investigates the oxidation properties of Fe-14Cr ferritic oxide-dispersion-strengthened (ODS) steel at various high temperatures (900, 1000, and $1100^{\circ}C$ for 24 h). The initial microstructure shows that no clear structural change occurs even under high-temperature heat treatment, and the average measured grain size is 0.4 and $1.1{\mu}m$ for the as-fabricated and heat-treated specimens, respectively. Y-Ti-O nanoclusters 10-50 nm in size are observed. High-temperature oxidation results show that the weight increases by 0.27 and $0.29mg/cm^2$ for the as-fabricated and heat-treated ($900^{\circ}C$) specimens, and by 0.47 and $0.50mg/cm^2$ for the as-fabricated and heat-treated ($1000^{\circ}C$) specimens, respectively. Further, after 24 h oxidation tests, the weight increases by 56.50 and $100.60mg/cm^2$ for the as-fabricated and heat-treated ($1100^{\circ}C$) specimens, respectively; the latter increase is approximately 100 times higher than that at $1000^{\circ}C$. Observation of the surface after the oxidation test shows that $Cr_2O_3$ is the main oxide on a specimen tested at $1000^{\circ}C$, whereas $Fe_2O_3$ and $Fe_3O_4$ phases also form on a specimen tested at $1100^{\circ}C$, where the weight increases rapidly. The high-temperature oxidation behavior of Fe-14Cr ODS steel is confirmed to be dominated by changes in the $Cr_2O_3$ layer and generation of Fe-based oxides through evaporation.

• Korean Journal of Materials Research
• /
• v.10 no.12
• /
• pp.793-798
• /
• 2000

The age-hardening behavior of unreinforced 6061 Al alloy and SiCp/6061 Al alloy composites reinforced with different size of SiC particle (average diameter ; 0.7$\mu\textrm{m}$ and 7.0$\mu\textrm{m}$) was investigated by hardness measurement, calorimetric technique and transmission electron microscopy. At 17$0^{\circ}C$ isothermal aging treatment, the peak aging time of 0.7$\mu\textrm{m}$SiCp/6061Al alloy composite and 7.0$\mu\textrm{m}$SiCp/6061Al alloy composite is shorter than that of unreinforced 6061Al alloy, and the aging of 7.0$\mu\textrm{m}$SiCp/6061Al alloy composite is accelerated more than that of 0.7$\mu\textrm{m}$SiCp/6061Al alloy composite. This acceleration is due to the increase of dislocation density by the compositeness with SiCp and the SiC particle size. In the peak aged condition, the major strengthening phase of these materials is intermediate $\beta$ phase(Mg$_2$Si), and the activation energy for the formation of $\beta$ phase is considerably decreased by the compositeness with SiCp and the increasing of SiC Particle site.

• The Journal of Korean Obstetrics and Gynecology
• /
• v.19 no.1
• /
• pp.219-235
• /
• 2006

Purpose : To investigate the medical information related to HRT online and the medical treatment of perimenopausal and postmenopausal women in the Dept. of Ob&Gy Korean Medicine Hospital, after the discontinuance of the WHI trial in U.S, July 2002. Methods : With the key-words "HRT", "Hormone Replacement therapy", "호르몬 대체요법(HRT)", 갱년기 증후군(perimenopausal syndrome)", “폐경기후증후군(postmenopausal syndrome)", I searched for the information from July 2002 to 2005 on DAUM, the representative portal site in Korea, and I've got a grasp of the tendency of the informational propagation on HRT. Moreover, I investigated chief complaints and tendency of give up HRT of the perimenopausal and postmenopausal women(aged between 47 and 60) who visited Dept. of Ob&Gy Korean Medicine Hospital for 2 years and 6 months since July 2002. Results : 1) Searching for the news on DAUM, I found; 2 articles on the methods of HRT: 4 on the positive effects of HRT: 4 on the general items including the positive effects of HRT: 19 on the side effects of HRT: 1 on the insignificant effect of HRT :4 on the apprehensions about HRT: 3 on the strengthening of the criteria on medical fees review: 3 on the discontinuance of HRT: 8 on the alternative materials and medicines to HRT: 4 on the guidance for the phyto-estrogen. 2) I analyzed chief complaints of 120 women. The majority of chief complaints were vasomotor symptoms like hot flush and sweating. There were only 4 patients who wanted to give up HRT. Conclusion : The side effects of HRT were objectively dealt with online but there was not enough effective and continuous guidance. In the case that a woman not on HRT wishes to overcome perimenopausal period through KM therapy, this information may have affected her decision. However, not many women who were already on HRT terminated the therapy for fear of side effects and switched to KM therapy. Promotion of KM therapy in improving health during perimenopausal and postmenopausal period is desperately needed.

• Journal of Korean Academy of Nursing Administration
• /
• v.9 no.3
• /
• pp.337-352
• /
• 2003

Purpose: The purpose of this study is to analyse research trends related to the evaluation of quality of nursing, thereby obtaining basic data relating to the identification of current situation of instrument development of quality of nursing, and of future research orientation and to the development of performance index of nursing organization. Method: The data were collected from June to December, 2002 through the review of total of 32 research papers which had evaluated quality of nursing among published papers in Korea from 1976 to August 2002. The analysis was done in terms of research period, the periodicals in which research papers were published, domains and the approaches of evaluation of nursing quality. The content analysis of lowest-level items amounting was performed using NIC developed by McCloskey & Bulecheck(1998) and consequential indices of quality of nursing developed by Chi(1995). Results: Twenty-three of 32 papers(71.8%) turned out to be published after 1995, indicating surging interest in the evaluation of quality of nursing from the mid 1990s. Also, ten of 12 research papers dealing with subjects' diseases were published after 1995. In content analysis of lowest-level items of the process-oriented evaluation of quality of nursing, the highest nursing intervention was patient education about procedure and treatment; followed in descending order by patient education about disease process, strengthening of communication, managing environment, infection control, admission care, defecation and urination care. In content analysis of lowest-level items of the outcome-oriented evaluation of quality of nursing, items of physical and psychological state, of patient and family satisfaction, of knowledge and home care, of change of patients' state, of addressing nursing issues, and of patient recovery were the outcome indicators in more than 60 percent research papers. Conclusion: The findings provided the foundation for their effective use in nursing practice with comparing and presenting various core evaluation items representing process and outcome domains.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.44 no.2
• /
• pp.133-139
• /
• 2018

Chemically damaged hair is vulnerable to external stimuli in daily life due to the weakened physical properties of the hair strand itself. The purpose of this work was to determine whether chemical conjugation between hair keratin proteins restores tensile strength and thus results inpreventing further deterioration under repeated combing. A model damaged hair tress was produced by a typical perm-process. Then, it was internally crosslinked by the bifunctional crosslinker (3-aminopropyl)triethoxysilane (APTES), via both silane coupling and carbodiimide chemistry. Physical properties, including tensile strength, Young's modulus, and plateau stress, were measured to verify the effect of internal crosslinking, and the existence of crosslinking was verified by Fourier transform infrared (FT-IR) spectroscopy. The degrees of hair breakage and split ends were evaluated by repeated combing-drying tests. Physical properties of chemically damaged hair were restored by internal crosslinking. Successful crosslinking of APTES via both silane coupling and carbodiimide chemistry was verified by FT-IR spectra. Prevention of breakage and split ends after repeated combing with heat was observed. Human hair can be weakened by chemical damage including perm-processing, so restoring such properties is a major issue in the hair care industry. This work shows that internal crosslinking of damaged hair via chemical conjugation would be a potent method to restore the healthy hair.

• Journal of Digital Convergence
• /
• v.18 no.4
• /
• pp.479-487
• /
• 2020

The purpose of this study is to identify a potential user's need for use and operational of the elderly day care center and to identify the problems and suggest development directions. The data collection was conducted on 320 ordinary people living in J-do through a questionnaire, and sought to understand the operational status of in-depth interview institutions for the heads and employees of six center. As a result of the analysis, a potential user's ware not aware of the functions and specific roles of day care center, the cost of facilities was covered by the government, and that facilities and the environment were important factors when using the center. In-depth interviews show that the current policy or system is far from reality and does not fit the status or role of the workers and the operational status of the agency, requiring the re-establishment of the on-site system. Based on the research results, the development direction of day care facilities requires active promotion and strengthening of family support for improving and enhancing awareness of day care facilities to citizens at the national level. Second, the quality of nursing services should be enhanced through improvements in facilities and the environment that reflect users' needs. Third, The government should improve the quality of nursing services by improving the poor employment conditions and treatment of workers to fit the reality.

• Journal of the Korean Society of School Health
• /
• v.13 no.1
• /
• pp.131-145
• /
• 2000

For the purpose of strengthening Dental Hygiene students' confidence and motivation in the Dental Hygiene Department and helping construct proper professionalism, survey on Dental Hygiene students' consciousness of attitude to and satisfaction of the course, career plan and occupation mind set was carried out. 530 three year students in 8 Dental Hygiene academies in Seoul and Kyonggi province were questioned. The results of the survery are as follows:. 1. Dental Hygiene students' motives consisted primarily of employment and a desire for professionalism 25% of them entered the course after one failure in the entrance examination and 17% had family members engaging in the dentistry field 84%, the largest portion, were from an academic high school. 24% had some knowledge of Dental Hygiene, which they had acquired from seniors, friends, and teachers. 2. Patient care and treatment assistance related matters were not considered important in the course. The weak points of the course turned out to be education in computers and foreign languages, but the weakest was the ability of patient care during clinical training. 53% had experiences had thought of changing their major while in the course because it didn't match their aptitude and interest. 3. As for a career after graduation, 49% worried about it Most students wanted to work at a dental hospital or general hospital, The most favored duty was coordination or reception or oral disease preventive work. They wanted to work untill they had a stable living. 68% answered they would get a job at an oral clinic and 70% said they would continue studying for self-realization. 4. Satisfaction with the major was high in students whose aptitude and interest matched the course, who had background knowledge of the major, and who. didn't think of changing the major but would continue studying resulting in statistically slight difference(p<0.001). As to satisfaction with the faculties, it was high in the students whose aptitude and interest matched the major and who didn't think about a career after graduation showing a slight difference(p<05, p<0l). As for satisfaction with clinical training, students whose aptitude and interest matched the major and who didn't consider changing the major answered positively showing a statistically slight difference(p<.001, p<.01). As to satisfaction with the course, it was high in the students who entered with aptitude and interest, who had preliminary knowledge, who didn't consider changing the major, and who didn't think about a career after graduation showing a statistically slight difference(p<.001, p<.05). 5. Occupation mind-set was positive for students who entered with interest and aptitude, who had preliminary knowledge, and who had not considered changing the major showing a statistically slight difference(P<.001). The higher the satisfaction with the major, faculty and clinical training was, the more positive the occupation mind-set was(p<.001).

• The Journal of Internal Korean Medicine
• /
• v.24 no.2
• /
• pp.220-232
• /
• 2003

Objective : The purpose of this study was to analyze the effects of HwangRyunHaeDok-Tang and combinations of constituent herbs on the arterial contraction. Methods : In order to investigate the effects Scutellariae Radix. Coptidis Rhizoma, Phellodendri Cortex and Gardeniae Fructus, in which one of them, two of them, and all of them, were used to exam. Results : The results were summarized as follows; 1. HwangRyunHaeDok-Tang significantly inhibited the contraction of artery induced by Norepinephrine(NE). However the atonic effect was slightly blunted when the vascular endothelial cell was removed. No significant change in the atonic effect of HwangRyunHaeDok-Tang was found when $_L-NNA$ was used as a preliminary treatment. These results indicate that the vascular atonic effect by HwangRyunHaeDok-Tang is slightly dependent on the endothelial cell, and that the HwangRyunHaeDok-Tang works directly to the vascular smooth muscle in creating the vascular atonic effect. 2. The pretreatment of HwangRyunHaeDok-Tang extract significantly inhibited the contractile response to additive application of $Ca^{2+}$ in the strips which were contracted by NE in $Ca^{2+}$-free solution. 3. HwangRyunHaeDok-Tang extract increased the contraction of arterial smooth muscle induced by KCl. Therefore, it can be concluded that HwangRyunHaeDok-Tang may block the NE-receptor or receptor-operated $Ca^{2+}$ channel. 4. It was determined that Scutellariae Radix, Coptidis Rhizoma and Phellodendri Cortex among the ingredients of HwangRyunHaeDok-Tang have a vascular atonic effect. In addition, those ingredients plays a role in strengthening the atonic effect by working with other herbal medicines. Gardeniae Fructus causes the blood vessel to contract. but it does not influence the atonic effects of other herbal medicines. However Gardeniae Fructus tends to inhibit the vascular atonic effect of Phellodendri Cortex. Conclusion : Based on the above results, it can be said that HwangRyunHaeDok-Tang can be applied to cure hypertension considering those three herbs have significant effects of relaxation.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.17 no.4
• /
• pp.905-913
• /
• 2003

Oriental medicine explains aging as the weakening of Kidney-ai, and Kidney-strengthening herbal medicines such as Yukmijihwang-tang have been studied for anti-aging effects. In Western Medicine, the hypothesis that reactive oxidant species(ROS) contribute to the aging process is generally accepted. It has been reported that Moutan Cortex Radicis extract (MCR) was the most effective constituent of Yukmijihwang-tang in decreasing ROS production in oxidative-stressed cells. The purpose of this study is to confirm the anti-oxidant effect of MCR on PC12 cells, the expression of Heme oxygenase (HO), Macrophage migradon inhibitory factor (MIF), Catechol-O-methyltransferase (COMT) using real time RT PCR. PC12 cells were treated without or with hydrogen peroxide in the presence or absence of MCR using MTS assay. Hydrogen peroxide decreased the viability of PC12 cells by 53% and MCR did not influence that of stressed PC 12 cells irrespective of dose or incubation period. However, MCR showed an inhibitory effect on production of ROS in stressed cells, both dose and incubation time dependently. In particular, 1 ㎎/㎖ of MCR for 24 h culture almost returned to normal level. In the quantiation of anti-aging related gene expression, MCR at 1 ㎎/㎖ increased the expression of HO by 370%, MIF by 180% and COMT by 280% through real time RT PCR. In conclusion, MCR treatment protected PC12 cells from hydrogen peroxide and decreased ROS production and enhanced anti-oxidative gene expression such as HO, COMT and MIF, which suggests that MCR is involved in controlling anti-aging of nerve cells through elimination of cytotoxic stimuli.

• Ecology and Resilient Infrastructure
• /
• v.6 no.3
• /
• pp.163-170
• /
• 2019

The civil engineering materials used to stabilize the slopes of new riverbanks have a great impact on the types and growth of vegetation introduced after the completion of construction procedure. Recently, microbial-derived, ${\beta}$-glucan- and xanthan gum-based biopolymers are attracting attention as an ecofriendly strengthening material of riverbanks that can possibly stimulate plant growth. This study aimed to assess ecological effects of biopolymer application on native plants in Korean riverbanks. In particular, since dominant plant species could shape characteristics of an ecosystem, we examined the effects of biopolymer on the dominant plant species in riverbanks. Overall, biopolymer did not affect seed germination rates of testing plant species. In contrast, plants grew more vigorously in the soil mixed with biopolymer compared to those in the control soil. The biomass of Echinochloa crus-galli especially increased around two times more in the biopolymer treatment. Plants produced heavier root biomass and leaves with larger specific leaf area, which possibly contributes to the tolerance of environmental stress like drought. These results suggest that biopolymers treated on river banks are expected to stimulate plant growth and increase stress tolerance of domestic dominant plant species.