• Transactions of Materials Processing
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• v.8 no.3
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• pp.309-309
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• 1999

Effects of rare earth metals addition and aging treatment on corrosion resistance and mechanical properties of super duplex stainless steels were investigated using optical/SEM/TEM metallographic examination, an X-ray diffraction test, a potentiodynamic anodic polarization test and a tensile test. The performance of the experimental alloy with 0.32% REM addition was compared with commercial super duplex stainless steel such as SAF 2507 when they were exposed to solution annealing heat treatment and aging treatment. The corrosion resistance in CF environments and mechanical properties of the experimental alloy were found superior to those of the commercial duplex stainless steel. The REM with larger atomic radii than those of Cr, Mo and W may fill vacancies inside the matrix and around the grain boundaries, retarding formation of harmful intermetallic σ and χ phases. In addition, fine REM oxides/oxy-sulfides (1-3㎛) seemed to enhance the retardation effects. With REM additions, strength and ductility increased due to the phase and grain refinement caused by fine REM oxides and oxy-sulfides.

• Transactions of Materials Processing
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• v.8 no.3
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• pp.301-301
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• 1999

Austenitic stainless steels such as AISI 316L have been used in equipment in which fluid flows at high speeds which can induce cavitation erosion on metallic surfaces due to the collapse of cavities, where the collapse is caused by the sudden change of local pressure within the liquid. Usually AISI 316L is susceptible to cavitation erosion. This research focuses on developing a better material to replace the AISI 316L used in equipment with high speed fluid flow, such as impellers. The effects of Rare Earth Metal (REM) additions on the cavitation erosion-corrosion resistance of duplex stainless steels were studied using metallographic examination, the potentiodynamic anodic polarization test, the tensile test, the X-ray diffraction test and the ultrasonic cavitation erosion test. The experimental alloys were found to have superior mechanical properties due to interstitial solid solution strengthening, by adding high nitrogen (0,4%), as well as by the refinement of phases and grains induced by fine REM oxides and oxy-sulfides. Corrosion resistance decreases in a gentle gradient as the REM content increases. However, REM containing alloys show superior corrosion resistance compared with that of other commercial alloys (SAF 2507, AISI 316L). Owing to their excellent mechanical properties and corrosion resistance, the alloys containing REM have high cavitation erosion-corrosion resistance.

• The Journal of Internal Korean Medicine
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• v.42 no.5
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• pp.976-981
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• 2021

Objectives: This study investigated the effectiveness of acupuncture for improving polycythemia-vera-related symptoms and quality of life. Methods: A 56-year-old woman diagnosed with polycythemia vera received acupuncture treatment between February 19, 2021, and August 26, 2021. We observed the changes in subjective symptoms and conducted myeloproliferative neoplasm symptom assessment form total symptom score (MPN-SAF TSS) questionnaire. Results: After 13 acupuncture treatment sessions over six months, symptoms of polycythemia vera, such as fatigue, bone pain, itching, and headache, improved. Conclusion: This study suggests that acupuncture may be a helpful treatment strategy for polycythemia vera patients suffering from significant symptom burdens and reduced quality of life.

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.248-253
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• 2023

Directly, it is not possible to measure the absorbed dose of radiopharmaceuticals in the organs of the human body. Therefore, simulation methods are utilized to estimate the dose in distinct organs. In this study, individual organs were separately considered as the source organ or target organ to calculate the mean absorption dose, which SAF and S factors were then calculated according to the target uptake via MIRD method. Here, ^99mTc activity distribution within the target was analyzed using the definition and simulation of ideal organs by summing the fraction of cumulative activities of the heart as source organ. Thus, GATE code was utilized to simulate the Zubal humanoid phantom. To validate the outcomes in comparison to the similar results reported, the accumulation of activity in the main organs of the body was calculated at the moment of injection and cardiac rest condition after 60 min of injection. The results showed the highest dose absorbed into pancreas was about 21%, then gallbladder 18%, kidney 16%, spleen 15%, heart 8%, liver 8%, thyroid 7%, lungs 5% and brain 2%, respectively, after 1 h of injection. This distinct simulation model may also be used for different periods after injection and modifying the prescribed dose.

• Journal of Korea Water Resources Association
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• v.39 no.8 s.169
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• pp.691-702
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• 2006

This study introduced a method to evaluate the probability of a specific area to be affected by a drought of a given severity and shows Its potential for investigating agricultural drought characteristics. The method was applied to South Korea as a case study. The proposed procedure included Standardized Precipitation Index(SPI) time series, which were linearly transformed by the Empirical Orthogonal Functions(EOF) method. These EOFs were extended temporally with AutoRegressive Moving Average(ARMA) method and spatially with Kriging method. By performing these simulations, long time series of SPI can be simulated for each designed grid cell in whole area. The probability distribution functions of the area covered by a drought and the drought severity are then derived and combined to produce drought severity-area-frequency(SAF) curves.

• Parasites, Hosts and Diseases
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• v.22 no.1
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• pp.116-126
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• 1984

The present study was designed to elucidate the recent prevalence of the intestinal protozoa and to demonstrate the relationship on prevalence of the surveyed population with their academic career and living conditions. During the period from May to July 1981, total 2, 735 fecal specimens were collected from the inhabitants of 11 areas in Gyeong-gi Do(province) near by Seoul City, and 6 areas in Jeonra Bug Do, southwestern part of Korea. The samples were fixed with SAF solution and were examined by formalin-ether sedimentation technique. The results are summarised as follows: 1, Overall positive rate of intestinal protozoa was 11. l% : Gyeong-gi Do, 10.7%; Jeonra Bug Do, 11.7%. 2. Five species of intestinal protozoa were detected: Entamoeba histolytica 0.69% : Entamoeba cali 5.52%; Endolimax nana 2.71%, Giardia lamblia 2.23%; lodamoeba biitschlii 0.18%. 3. Highest positive rates among the examined areas were recognized: Incheon City of Gyeong-gi Do, 26.7%; Im-sil Gun(county) of Jeonra Bug Do, 19.9%. 4. By species, E. nana showed the highest prevalence rate (13.74%) in Incheon City, and E. histolytica (2.37%) and E. coli (9.95%) in Im-sil Gun. 5. Prevalence of E. histolytica in rural areas was higher than in urban areas. 6. No significant difference in the prevalence rate by sect and age was recognized, although the group under 10 years and over 60 years were lower than in other age groups. 7, The highest positive rate of E. histolytica was observed in pauper group and significant linearity of prevalence rate of E. histozytica by monthly income was observed. 8. The inhabitants who used conventional latrine showed higher prevalence, 11.5%, than the group of inhabitants who used modified privy. 9. Although no significant difference of positive rate was recognized by academic career, but the lowest prevalence rate was observed in college graduates. 10. Over half of the surveyed population, 64.8% has no experience on anthelmintic practice. Number of anthelmintic application resulted no difference in prevalence. In conclusion, prevalences of intestinal protozoa in Gyeong-gi Do and Jeonra Bug Do decreased remarkably in comparison with those of one decade before. However, economic level, academic career and anthelmintic administration seemed no essential reasons for such declination.

• Journal of the Korean Magnetics Society
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• v.23 no.5
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• pp.154-158
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• 2013

We have analyzed the magnetization curves measures by using VSM and MOKE in synthetic antiferromagnetic coupled CoB/Ru/CoB thin film. The measured results were compared with calculated ones by Stoner-Wohlfarth model based on the magnetization behavior of two ferromagnetic layers ($M_1$, $M_2$). The calculated total magnetization ($M_{tot}=M_1+M_2$) and single layer magnetization($M_1$) behaviors were compared with measured results by using VSM and MOKE, respectively. The total magnetization curve ($M_{tot}=M_1+M_2$) showed reversible magnetization behavior with flopping field of about 50 Oe. While single layer magnetization ($M_1$) behaviors showed irreversible magnetization behavior in the field range of $H_F$ < H < $H_F$. These magnetization behaviors were explained by the angle difference between magnetization directions of two ferromagnetic layers in SAF sample.

• Journal of Life Science
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• v.12 no.2
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• pp.219-225
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• 2002

The organization of eukayotic chromatin into specific conformation that are associated with transcription, replication, reapir and other nuclear processes are achieved via a series of DNA-protein interaction. These interactions are mediated by a range of DNA-binding domains such as SAP domain et at. By searching S. pombe genomic DNA database, we have found a gene named SAPuvs (SAP UV Sensitive) whose amino acid sequence is in part similar to SAP domain of Arabidopsis poly (ADP-ribose) polymerase and Ku7O. Knock-out cell of S. pombe SAPuvs gene was constructed using Ura4 as a selection marker. Survival analysis of knock-out cell indicated that treatment with UV significantly reduces the survival compared to wild type cell. Potentiation of MMS-induced cytotoxicity by 3AB post-treatment was observed in wild type cells, but not in knock-out cells. These data suggested that the protein encoded by SAPuvs gene is associated with chromatin reorganization during DNA repair.

• Korean Journal of Occupational Health Nursing
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• v.8 no.2
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• pp.176-192
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• 1999

The purpose of this study is to analysis change of industrial health and safety before and after economic crisis(1997~1998). The data were obtained through mail interview with health supervisor(occupational health nurses) during February, 1999. The final sample was consisted of 127 respondents, 97 are selected in this study. The major findings were as follows: First, the percent of industries whose empl safe supervisors, physicians and industry hygi decreased in number is 79.4%, 3.8%, 50.0 21.5% in each. Second, man receiving over 1.5 million won as an average wage of health supervisor is 27.5% in 1997, but it decreased to 25.3% in 1998. Man receiving under 100~150 million won is 48.4% in 1997, but this percent decreased to 36.3% in 1998 and 13.6% of health supervisor regularly were transformed to contingent worker in 1998. Third, especially, budgets for health and saf work place decreased to 13.8% in 1998 than 19. Fourth, industrial accident case, unre accident case, occupational disease decreased than 1997, but mortality from industrial a increased in 250%. Fifth, according to the health diagnosis report, number of case with evidence of disease increased in liver disease, tuberculosis and so on, and number of case with evidence of occupational disease increased in noise induced hearing loss, pneumoconiosis. organic solvent poisoning and so on. Sixth, this survey shows that health council, health education in duty of health supervisor was conducted passive in 1998 thin 1997, and percent of hold two or more positions is 47.6% in medical insurance, 10.7% in accountant's business 8.3 in secretory. 7.1% in telephone operator awl 22.6% in etc. Seventh, distress of health supervisor after economic crisis is 30.9% in employment instability, 19.8% in hold two or more positions and decrease of budgets. For subjugation of the trouble, the respond of active policy of government occupied most.

• Geomechanics and Engineering
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• v.32 no.6
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• pp.583-600
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• 2023

The resilient modulus (M_R) of various pavement materials plays a significant role in the pavement design by a mechanistic-empirical method. The M_R determination is done by experimental tests that need time and money, along with special experimental tools. The present paper suggested a novel hybridized extreme gradient boosting (XGB) structure for forecasting the M_R of modified base materials subject to wet-dry cycles. The models were created by various combinations of input variables called deep learning. Input variables consist of the number of W-D cycles (WDC), the ratio of free lime to SAF (CSAFR), the ratio of maximum dry density to the optimum moisture content (DMR), confining pressure (σ₃), and deviatoric stress (σ_d). Two XGB structures were produced for the estimation aims, where determinative variables were optimized by particle swarm optimization (PSO) and black widow optimization algorithm (BWOA). According to the results' description and outputs of Taylor diagram, M1 model with the combination of WDC, CSAFR, DMR, σ₃, and σ_d is recognized as the most suitable model, with R² and RMSE values of BWOA-XGB for model M1 equal to 0.9991 and 55.19 MPa, respectively. Interestingly, the lowest value of RMSE for literature was at 116.94 MPa, while this study could gain the extremely lower RMSE owned by BWOA-XGB model at 55.198 MPa. At last, the explanations indicate the BWO algorithm's capability in determining the optimal value of XGB determinative parameters in M_R prediction procedure.