• Journal of the Korean Society for Precision Engineering
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• v.25 no.7
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• pp.116-123
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• 2008

In the fossil power plant, the reliability of the components which consist of the many welded parts depends on the quality of welding. The residual stress is occurred by the heat flux of high temperature during weld process. This decreases the mechanical properties as the strength of fatigue and fracture or causes the stress corrosion cracking and fatigue fracture. Especially, the accidents due to the residual stress occurred at the weld parts of high-temperature and high-pressure pipes and steam headers. Also, the residual stress of the welded part in the recently constructed power plants has been brought into relief as the cause of various accidents. The aim of this study is the measurement of the residual stress using the x-ray diffraction method. The merits of this are more accurate and applicable than other methods. The materials used for the study is P92 steel for the use of high temperature pipe on super critical condition. The variables of tests are the post-weld heat treatment, the surface roughness and the depth from the original surface. The test results were analyzed by the distributed characteristics of the full width at half maximum intensity (FWHM) in x-ray diffraction intensity curve and by the relation of hardness with FWHM.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.11
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• pp.801-805
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• 2013

In this study, electrocaloric effects of Pb-free $(Ba_{0.85}Ca_{0.15})(Ti_{0.92}Zr_{0.08})O_3$ ferroelectric ceramics were investigated and discussed using the characteristics of P-E hysteresis loops at wide temperature range from room temperature to $140^{\circ}C$. The remnant polarization $P_r$ and coercive field $E_c$ were decreased with increasing temperature. The temperature change ${\Delta}T$ by the electrcaloric effect was calculated by Maxwell's relations, and reached the maximum of ~0.15 at $120^{\circ}C$ under applied electric field of 30 kV/cm.

• Polymer(Korea)
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• v.27 no.4
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• pp.385-391
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• 2003

Lithium p-［Methoxyoligo(ethyleneoxy)］ benzenesulfonates (LiEOnBS) with different repeating unit of ethylene oxide were synthesized and were used for preparing gel-polymer electrolytes. The conductivities and lithium ion transference number were measured as a function of Li-salt concentration and repeating unit of ethylene oxide of the LiEOnBS. The maximum conductivity of the resulting gel-polymer electrolyte was found to be 4.89${\times}$10$\^$－4/ S/cm (LiEO7.3BS, 0.5 M) at 30$^{\circ}C$. The lithium ion transference number (t$\sub$Li$\sub$＋//) measurement were performed by means of the combination do polarization and ac impedance methods in gel-polymer electrolytes. Lithium ion transference number was measured to be in the range of 0.75∼0.92 for the LiEOnBS containing gel-polymer electrolytes. The maximum t$\sub$Li$\sub$＋// was obtained to be 0.92 for the 0.1 M LiEOnBS containing polymer electrolytes. The synthesized LiEOnBS showed single ion transport like characteristics when n was large than 3.

• Ecology and Resilient Infrastructure
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• v.4 no.4
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• pp.193-199
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• 2017

In this study, changes of soil properties including soil texture, specific surface area, organic matter content, pH, cation exchange capacity and exchangeable cations content were investigated in response to strong acid or base accident. The properties changed significantly when the soil reacted with 10 M HCl or 1 M NaOH (i.e., when one gram of soil received 50 and 5 mmol of HCl or NaOH), respectively. When the soil reacted with 10 M HCl or 1 M NaOH solution, soil texture changed from sandy loam to loamy sand and specific surface areas decreased from $5.84m^2/g$ to 4.85 and $1.92m^2/g$, respectively. The soil organic matter content was reduced from 3.23% to 0.96 and 0.44%, and the soil pH changed from 5.05 to 2.35 and 10.65, respectively. The cation exchange capacity decreased from 10.27 cmol/kg to 4.52 and 5.60 cmol/kg, respectively. Especially, high concentrations of $Al^{3+}$ or $Na^+$ were observed in acidic or basic spills, respectively, which is likely to cause toxicity to terrestrial organisms. The results suggest that restoration of soil properties, as well as soil remediation, needs to be carried out to maintain the soil function in chemical spill sites.

• Clinical and Experimental Reproductive Medicine
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• v.37 no.2
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• pp.153-158
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• 2010

Objective: To compare the clinical outcomes between oral micronized progesterone and dydrogesterone as a luteal phase support in stimulated intrauterine insemination (IUI) cycles. Methods: A retrospective analysis was performed in 183 IUI cycles during January 2007 to August 2009. Superovulation was achieved by using gonadotropins combined with or without clomiphene citrate. The luteal phase was supported by oral micronized progesterone 300 mg/day (n=136 cycles) or dydrogesterone 20 mg/day (n=47 cycles) from day of insemination. Results: There were no significant differences in clinical characteristics such as age of female, infertility factors, number of mature follicles ($\geq$16 mm), total motile sperm counts, and endometrial thickness on triggering day between the two groups. The clinical pregnancy rates per cycle were similar between the two groups (21.3% in the micronized progesterone group vs. 19.1% in the dydrogesterone group, p=0.92). The clinical miscarriage rate tended to be 3-fold higher in the micronized progesterone group (34.5% vs. 11.1%, p=0.36). Conclusion: Supplementation of oral dydrogesterone as a luteal support has similar clinical outcomes compared with oral micronized progesterone. Large-scaled randomized study would be required to confirm our findings.

• Proceedings of the Korean Society of Food and Cookery Science Conference
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• 2003.10a
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• pp.92-92
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• 2003

맥문동 추출액을 제조하여 그 추출액을 밀가루중량의 2∼6% 첨가한 식빵의 제빵특성을 조사하였다. 맥문동 추출액에는 총가용성분은 100m1 당 10.67g이며, 총당은 9.77g, 환원당은 5.l0g, 회분은 0.40g, 사포닌함량은 0.80g이였다. 식빵제조시 반죽의 pH는 대조군은 4.96이었으며 맥문동 추출액을 2, 4, 6% 첨가한 군은 각각 4.91, 4.87, 4.85로 나타났다. 빵의 무게는 대조군, 2%, 4%첨가군은 모두 404.3g 이었으며 6%첨가군은 407.3g이었다. 굽기손실률은 6% 첨가군이 9.50%로 가장 낮았으며 랑의 부피는 대조군이 1793.ml, 2% 첨가군은 1780.0ml, 4%와 6% 첨가군은 1610.0ml 이었다. (중략)

• Journal of the Korea Concrete Institute
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• v.29 no.1
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• pp.85-92
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• 2017

This study examines the characteristics of mortar mixed with various boron compounds. The adapted boron compounds, classified into acid, slightly alkaline and strongly alkaline with respect to the value of the pH are acid-based boron (AA), low-alkaline-based boron (AB), and high-alkaline-based boron (HB). The pH test, setting test and compressive strength test are performed to evaluate the physical and chemical properties of mortar, and SEM imaging is conducted to analyze the microstructure of mortar. The measured pH shows that the specimens mixed with boron compounds have lower pH than the basic mortar without boron and that loss of pH occurs according to time. The setting test reveals that the initial and final setting times of the specimens mixed with boron compounds occur later than the basic mortar, which disagrees slightly with the previous literature stating that the setting time can be shortened according to the alkalinity. From the compressive strength test and SEM imaging results, it is recommended to determine the optimal content of boron considering type and composition of the boron compounds.

• Journal of Korean Clinical Nursing Research
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• v.21 no.1
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• pp.92-104
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• 2015

Purpose: The purpose of this study was to identify the types of violence and coping methods experienced by general hospital nurses. Methods: Data were collected from March 17 to 24, 2014, using self-report questionnaires. Responses from 449 nurses were analyzed. Results: The majority of the respondents experienced violence from patients, visitors, doctors, and other nurses. Verbal violence was more frequent than physical threats and physical violence. Most violence happened in ERs, followed by surgical units, and ICUs. The most frequent response by nurses after violence was an emotional response, especially 'anger' ($4.01{\pm}1.059$). Based on general characteristics, the responses were significant for professional experience (F=2.935, p=.013) and work areas (F=2.290, p=.021). The most frequent coping method for nurses after violence had occurred was to 'just complete their duties as if nothing happened'. Conclusion: Most nurses are exposed to frequent violence, but they feel defenseless. These results suggest that hospital should improve the respective organizational cultures and develop promotional programs and administrative policies to prevent violence. In addition, educational programs should be provided for nurses to improve their attitudes and abilities to cope with violence. Also, hospitals should offer sufficient support, stress reduction programs and counseling programs for nurses.

• Proceedings of the KAIS Fall Conference
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• 2008.11a
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• pp.90-92
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• 2008

본 논문에서는$xAg_2O$-(5-x)$Na_2O$-36CaO-$10TiO_2$-$19.5P_2O_5$ (mol ratio)의 유리조성으로부터 $Ag_2O$의 함량을 변화시켜 유리의 제조 및 특성평가를 하였다. 제조된 유리는 TG-DSC를 통하여 열적특성을 관찰하였으며, 항균특성은 staphylococcus aureus균주에 대하여 항균특성을 평가하였다. 평가결과 열적특성은 $Ag_2O$함량이 증가할수록 결정화온도가 낮아짐이 관찰되었고, 항균특성 역시 $Ag_2O$성분의 함량이 증가 할수록 항균특성이 증가하는 것으로 관찰되었다.

• Proceedings of the KAIS Fall Conference
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• 2005.05a
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• pp.89-92
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• 2005

본 연구에서는 미량원소 함유 $K_2O-CaO-P_2O_5$유리를 제조하였으며, 화학비료와의 혼합을 통하여 얻어진 유리질 비료를 사용하여 작물배지 적합성 및 친환경성을 평가하였다. 용출특성의 경우 유리조성변화를 통하여 장기 및 단기용출이 가능하였으며, 벼에 적응한 결과 생육, 수량은 대조구와 유사하였으며, 식미치의 경우 보다 우수하였다. 또한, 용탈수 분석으로부터 환경친화적 유리질 비료로서의 가능성을 보였다.