To eliminate nozzle clogging during continuous casting of ship plate steel and reduce the calcium addition required, the composition of CaO-MgO-Al2O3 inclusions in the liquid phase region must be controlled. Thermodynamic calculations using FactSage show that when the balanced Al content is 0.03 mass %, aCa in the liquid steel is 1-10 ppm, and aMg is 0.01-0.3 ppm; and when the balanced Al content is 0.06 mass %, aCa in the liquid steel is 1-30 ppm, and aMg is 0.05-0.9 ppm. The CaO-Al2O3-CaS inclusions can be controlled in the liquid region below 1600°C at aCa values of 5 ppm, 15 ppm, and 30 ppm, and the balanced Al content should be controlled in the range of 0.001-0.050, 0.005-0.250, and 0.010-0.50 mass %, respectively. Based on theoretical analysis, the refining slag composition should be controlled to 45-53 mass % CaO, 30-37 mass % Al2O3, 6-12 mass % SiO2, and 6-8 mass % MgO. Optimization of the slag system and steel composition can reduce, or even eliminate, the requirement for calcium treatment. The total oxygen content in the slab can be controlled to 15-21 ppm, with typical micro-inclusions < 10 μm in size, with compositions in the CaO-Al2O3-MgO and CaO-Al2O3-CaS systems.

The effect of two refining slags (A: 1.0-1.8 CaO/Al2O3 ratio, 11-20 wt% SiO2; and B: 1.0-1.2 CaO/SiO2 ratio, 25-35 wt% Al2O3) on the inclusion morphology of a carbon structural steel (Q235B) was studied by controlling the balance between the steel and the refining slag at 1600°C in a Si-Mo resistance laboratory furnace. The results showed that most of the inclusions in the molten steel balanced with slag A were formed by a low-melting CaO-MgO-Al2O3-SiO2 system with a total oxygen content (T[O]) being fixed at 6-13 ppm. The inclusions in liquid steel balanced with the slag B were mostly formed by the CaO-MnO-Al2O3-SiO2 system, with T[O] controlled to 19-26 ppm. The overall size of the inclusions under balance conditions was higher in the steel reacted with the slag B than that reacted with slag A, with the latter showing more inclusions smaller than 3 μΐη. In order to generate a large number of spherical CaO-MgO-Al2O3-SiO2 inclusions smaller than 3 μηι while decreasing the T[O] in the resulting steel, the composition of slag A should be used. This composition allowed improving the cleanliness of the slab, and is also advantageous for the castability of the molten steel.

ABSTRACT Background: To investigate the effect of the personality traits on development of acute moun-tain sickness (AMS). Methods: One hundred and eighty-nine healthy male subjects transported from the plains (Chengdu, China) to high altitude area (Tibet, China) were enrolled in this study. Ninety-six sub-jects experienced AMS within two days after arriving at the Tibet plateau (AMS group). There were 93 subjects without AMS (healthy control without AMS group). The symptoms of AMS, state trait anxiety and personality traits of subjects were assessed using self-assessment and AMS questionnaire (Chinese criteria). Results: The AMS group had a significantly higher prevalence of self-assessed anxiety, compared with the healthy control group without AMS. Personality traits estimation based on data obtained by Eysenck personality questionnaire revealed higher neuroticism and extraversion scores in the AMS group. Neuroticism, extraversion and anxiety level expressed highly significant levels of mutual concordance. Conclusion: The anxiety level was the highest in patients with AMS and it corroborated with neuroticism and extraversion level from the Eysenck scale. Psychological disturbances and extra-version can affect the development of AMS in rapid entry population. It would be helpful for people with anxiety-trait or personality traits to deal with the stress, in order to decrease the risk of developing AMS.

RESUMEN Objetivo: Investigar el efecto de los rasgos de personalidad en el desarrollo del mal agudo de montaña (MAM). Métodos: Ciento ochenta y nueve hombres sanos transportados desde las llanuras (Chengdu, China) al área de altitudes altas (Tíbet, China) fueron incluidos en este estudio. Noventa y seis sujetos experimentaron MAM dentro de dos días después de llegar a la meseta del Tíbet (grupo con MAM), mientras que 93 sujetos permanecieron sanos, sin MAM (grupo de control). Los síntomas de MAM, ansiedad de estado-rasgo, y los rasgos de la personalidad de los sujetos fueron evaluados utilizando la autoevaluación y el cuestionario MAM (criterios de China). Resultados: El grupo MAM tuvo una prevalencia significativamente mayor de ansiedad auto-evaluada, en comparación con el grupo de control sano sin MAM. La valoración de los rasgos de personalidad basada en datos obtenidos mediante el cuestionario de personalidad de Eysenck arrojó puntuaciones de mayor neuroticismo y extraversión en el grupo MAM. El nivel de neuroticismo, extraversión y ansiedad expresó un nivel de concordancia mutua altamente significativo. Conclusión: El nivel de ansiedad fue mayor en los pacientes con MAM y se correspondió con el nivel de neuroticismo y extraversión de la escala de Eysenck. La extraversión y los disturbios psicológicos pueden afectar el desarrollo de MAM en la población de entrada rápida. Sería útil para las personas con rasgos de ansiedad rasgo o rasgos de personalidad lidiar con el estrés, con el fin de disminuir el riesgo de desarrollo de MAM.

Iron-acceptor pairs (Fe-A, A = B, Al, Ga, and In) in silicon were investigated using an ionic-based model, which incorporates the valence electron cloud polarization and the lattice relaxation.Our results are generaly in good agreement with the experimental trends among the Fe-A pairs, describing the increase in the pair donor energy level with increasing A principal quantum number and decreasing pair separation distance, and the pair configurational symmetries.