• Current Applied Physics
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• v.18 no.11
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• pp.1248-1254
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• 2018

Magnetization versus temperature and magnetic-field measurements, M(T, $H_a$), have been carried out to study the magnetic and critical properties of polycrystalline $La_{1-x}Ba_xCoO_3$ (x = 0.3 and 0.5) cobaltites. These compounds with the density of ${\sim}6.2g/cm^3$ crystallized in the $R{\bar{3}}c$ rhombohedral and $Pm{\bar{3}}m$ cubic structures, respectively. With an applied field $H_a=200Oe$, M(T) data have revealed that the samples with x = 0.3 and 0.5 exhibit the ferromagnetic-paramagnetic (FM-PM) phase transition at the Curie temperature points $T_C=202$ and 157 K, respectively. At 4.2 K, the saturation magnetization ($M_{sat}$) decreases from 35.9 emu/g for x = 0.3-26.1 emu/g for x = 0.5. Particularly, the critical-behavior analyses in the vicinity of $T_C$ reveal all samples undergoing a second-order phase transition, with critical exponent values (${\beta}=0.328$ and ${\gamma}=1.251$ for x = 0.3, and ${\beta}=0.331$ and ${\gamma}=1.246$ for x = 0.5) close to those expected for the 3D Ising model. This proves short-range magnetic order existing in $La_{1-x}Ba_xCoO_3$. We believe that magnetic inhomogeneities due to the mixture of hole-rich FM regions (confined in the trivalent-cobalt hole-poor anti-FM matrix) and uniaxial anisotropy prevent long-range order in $La_{1-x}Ba_xCoO_3$.

• Progress in Superconductivity
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• v.12 no.1
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• pp.6-11
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• 2010

The milling effects of a precursor $Y_2BaCuO_5$ (Y211) powder having 1 wt.% $CeO_2$ on the microstructure and critical current density ($J_c$) of liquid infiltration growth (LIG) processed $YBa_2Cu_3O_{7-y}$ (Y-123) bulk superconductors were investigated. The microstructure analysis revealed that the Y211 size in the final Y-123 products decreased with increasing the milling time and a relatively high density and uniform distribution of Y211 inclusions were observed in the sample prepared using 8 h milled powder. However, the unexpected Y211 particles coarsening was observed from the 4 h milled sample which was further increased for 10 h milled sample. Critical current density ($J_c$) of the LIG processed Y-123 bulk superconductors was found to be dependent on the milling time of the Y211 precursor powder. The $J_c$ increased with the increase of milling time and reached up to a maximum at 8 h in the self field while 10 h milled sample showed lower $J_c$ at the same field which might be due to the exaggerated growth and non-uniform distribution of Y211 particles.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.19 no.1
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• pp.46-56
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• 2012

Purpose: The purpose of this study was to identify the relationships among professional self-concept, critical thinking disposition and clinical competence in nursing students. Method: The participants in the study were 505 nursing students, 262 associate degree nursing students and 243 baccalaureate nursing students, all in schools in Gwangju or South Jeonla Province. A questionnaire survey was conducted from April 25 to May 27, 2011. Statistical processing was performed with SPSS 18.0 Version and the data were analyzed using t-test, ANOVA, Scheff$\acute{e}$ test, Pearson correlation coefficients, and multiple stepwise regression. Results: There was a positive correlation among clinical competence and professional self-concept, critical thinking disposition. The most effective factor for clinical competence was professional practice in professional self-concept, followed by prudence and objectivity in critical thinking disposition. The total explanation of clinical competence was 46.2%. Conclusion: The results of this study indicate confirm that professional self-concept and critical thinking disposition have an effect on clinical competence in nursing students. Accordingly in order to improve clinical competence, it is necessary to provide practice environment and educational curriculum that enhance the professional self-concept and critical thinking disposition of nursing students.

• Journal of Mechanical Science and Technology
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• v.18 no.6
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• pp.915-923
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• 2004

This study investigated the fatigue lives and mechanical properties of the carbon black filled natural rubber for the vibration-proof parts of the railway vehicle and automobile. The carbon blacks were one of the sources of crack nucleation and crack propagation in the rubber matrix, like the cementite and the maganese sulfide in iron matrix. Different kinds of carbon blacks resulted in different fatigue lives, critical J-values, and fracture morphologies. It was noticed that the critical J-value remained almost the same regardless of the length of a pre-crack. In addition, different kinds of carbon blacks generated different fracture morphologies, and microscopic and macroscopic roughnesses. The critical J-value has linear relations to the roughness, and it seemed related to the size distribution of carbon black particles. By reviewing all the experi-mental data, we found the factors that were related to the fatigue lives, and the logarithmic value of the fatigue life could be linearly expressed by the combination of the critical J-value and the macroscopic roughness. We also proposed a new estimative equation of fatigue life.

• Current Research on Agriculture and Life Sciences
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• v.3
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• pp.44-54
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• 1985

In order to determine the critical head values of boiling and piping, several experiments were performed for 3 cases of model dykes on 7 kinds of pervious foundations. The results obtained are as follows : 1. It appears that the coarser and the denser the foundation material, the higher the critical heads of boiling and piping, and that the lower the permeability of the foundation, the higher the critical heads of boiling and piping. 2. A difference in head between the moments of boiling and piping is greater in the case 2 or case 3 than in the case 1 because of the additional hydraulic resistance. And it is found that the coarser the foundation material, the greater the head difference. 3. The critical heads of boiling and piping is directly prortional to the seepage length. 4. The piezometric heads close to the singular point are of the same magnitude, provided that the geometry of the model dyke and foundation material are the same. 5. Variations of the weight of model dyke can not affect the critical head. According to the conclusions shown above, the critical head of piping can be more practically predicted for prototype using the results from laboratory tests on scale model.

• Journal of Korean Academy of Nursing
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• v.34 no.5
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• pp.712-721
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• 2004

Purpose: This investigation examined the effect of PBL on the meta-cognition, critical thinking, and problem solving process. Method: The research design was pre-posttest with a none qui valent control group design. Scenarios for PBL sessions were developed on the basis of textbooks and patients' charts and tested for content validity. Seventy six nursing students who took a 'Nursing Process' course from two nursing schools participated in the experimental group and control group. The experimental group performed PBL during the semester. Meta-cognition and problem solving processes were assessed by questionnaires which were developed using pedagogics. Critical thinking was measured by the CCTST(California Critical Thinking Skill Test) Form 2000. The data was analyzed by repeated measure (pretest-posttest) MANOVA, and correlation analysis. Result: PBL improved the participants' meta-cognition and problem solving process but not critical thinking. The relationship between meta-cognition and the problem solving process was supported but the relationship between critical thinking and problem solving was not supported. Conclusion: These results suggest that PBL has a positive effect on nursing students' educational outcomes. To improve the problem solving ability of nursing students, PBL should be applied to more subjects in the nursing curriculum.

• Journal of Korean Critical Care Nursing
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• v.4 no.2
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• pp.1-14
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• 2011

Purpose: This study was aimed to understand and describe the Korean critical care advanced practice nurses' work experience. Methods: Data was collected through 2 focus group interviews that were held in two different university hospitals in Seoul, Korea. All interviews were recorded and transcribed, and data were analysed using modified qualitative content analysis. Results: Ten themes were drawn from data analysis. They are "Various and complex tasks", "Excellency of advanced nursing practice", "Pressure and responsibility accompanied with pride", "Role identity confusion", "Role conflict", "Leaping and evolving role", "Gap between role and outcome evaluation", "Underestimated outcomes", "Where are my outcomes?" "Searching for outcomes: publicize the role". Conclusion: The results of this study help to understand the role of Korean critical care advanced practice nurses and to guide to outcome evaluation of their role effectiveness. Developing qualitative outcome indicators, cost-effectiveness ananlysis of Korean critical care advanced practice nurses' role, and accumulation of evidences through researches on outcome evaluation will be needed to successfully settle down advanced practice nursing in Korea.

• Journal of muscle and joint health
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• v.29 no.2
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• pp.124-132
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• 2022

Purpose: The purpose of this study was to investigate the relationships among critical thinking disposition, problem solving ability, and triage competency in nurses working in Emergency Rooms (ERs). Methods: This cross-sectional study, conducted in August and September 2021, involved 118 ER nurses from three hospitals in the Gyeonggi-do metropolitan area. The data were analyzed using t-test, ANOVA, Scheffé test, Pearson correlation coefficients, and multiple linear regression analysis using SPSS for Windows version 25.0. Results: The mean score of triage competency among ER nurses was 87.63±15.65. In the regression model, age, ER experience, triage experience, critical thinking disposition, and problem solving ability predicted 52% of the triage competency. Both critical thinking disposition and problem-solving ability were noted to be significant (β=.32, p<.001; β=.36, p<.001, respectively). Conclusion: Critical thinking disposition and problem solving ability of ER nurses were identified as major factors in triage competency. To improve ER nurses' triage competency and enhance critical thinking disposition and problem solving ability, a systematic and ongoing program should be developed and implemented.

• Journal of the Korean Society of Tobacco Science
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• v.6 no.2
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• pp.155-168
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• 1984

Field test were conducted to select the best method for soil phosphorus test and to obtain the critical levels of each method for P fertilizer recommendations based on tobacco production. Truog method was recognized to be the mort suitable one for soil P test. N. Carolina, Bray No.1 and Olsen methods were followed in order. Bray No. 2 and Lancaster methods showed the least satisfaction. The critical levels of available P by lancaster, Bray No. 1, N. Carolina,01sen, and Truog methods were 55ppm, 32ppm, 21ppm, 19ppm, and 22ppm, respectively. Below the critical level a large yield response can be expected with 10kg $P_2O_5$/10a, above critical level little or no response is expected. In soils the more the initial available p, the more available P was carried over, while the more the total amount of silt and clay, the less the residual P was found. The increase in residual P by 10kg of $P_2O_5$ was greater than that of 5kg/10a. The chemical composition and the price of the cured leaf were not affected by the $P_2O_5$ application, indicating that the increase in the rate of $P_2O_5$ application would not exert on the quality of tobacco.

• Journal of Microbiology and Biotechnology
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• v.13 no.6
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• pp.998-1000
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• 2003

This study was carried out to elucidate the mode of bacteriostatic property of xanthostatin (XS), a novel depsipeptide antibiotic with an N-acetylglycine side chain and selective antimicrobial activity against Xanthomonas spp. Two biotransformed XSs were isolated by the treatment of XS with the cell lysate of Xanthomonas campestris pv. citri, a solvent partition, preparative TLC, and HPLC. Structure determination of those two biotransformed XSs demonstrated deletion of the N-acetylglycine side chain. Noteworthily, they showed no antimicrobial activity against Xanthomonas spp. This result suggests that the N-acetylglycine side chain plays a critical role in the antimicrobial activity of XS, and that the bacteriostatic property of XS is due to susceptibility of the ester bond between the hexadepsipeptide nucleus and the N-acetylglycine side chain to hydrolytic enzyme(s) produced by Xanthomonas spp.