Phosphate capacity of CaO-AI2O3 slags containing CaF2, BaO,Li2O,or Na2O

Phosphorus partition ratios between CaO-Al₂O₃ and CaO-Al₂O₃-CaF₂ fluxes and Fe-C_sat-P alloys have been measured as a function of slag composition at 1500 °C. The effects of additions of BaO, Li₂O, and Na₂O to the CaO-Al₂O₃-CaF₂ system on the phosphorus partition ratios at 1400 °C and 1300 °C have been measured. From the partition ratio, and assuming that the oxygen potential is controlled by C-CO equilibrium, the phosphate capacities of the fluxes were calculated. Also, the activities of Li₂O and Na₂O were measured as a function of slag composition at 1300 °C by equilibrating the flux and the metal with Pb-Li or Pb-Na alloy and CO in a graphite crucible. The results indicate that phosphorus partition ratios with carbon-saturated iron and the phosphate capacities for additions of more basic oxides decrease in the following order: Na₂Oτ;Li₂Oτ;BaO. The activities of Li₂O and Na₂O in calcium aluminate fluxes have large negative deviations from ideal behavior; the activity coefficients at infinite dilution are on the order of 0.05 and 10^-5, respectively. Formerly Graduate Student, Department of Metallurgical Engineering and Materials Science, Carnegie Mellon University     

Effect of Strong Basic Oxide (Li_2O, Na_2O, K_2O and BaO) on Property of CaO-Based Flux

Intraditionalconvertersteelmakingprocess ,therephosphorizationofliquidsteelcausedbyladleslagstakesplacebecausetheoxidabilityandbasicityofslagsaredecreasedwhenthedeoxidizingandal loyingoperationsofsteelarecarriedoutinladle .Atpresent ,mainmeasuresofcontrollingrephosphori zationincludeincreasingoriginalbasicityandoxid abilityofslags ,whichcanincreasethemeltingpoint ,viscidityofslagsandtheamountofworkfordeoxidizationandalloyforalloying .Atthesametime ,theslagswithhighoxidabilityincreasetheox ygen…     

Li2O、Na2O、K2O、BaO对CaO基钢包渣系性能影响的实验研究

为改善钢包渣性能以控制钢包中钢液回磷,以Li2O、Na2O、K2O、BaO作添加剂替代模拟的CaO基钢包渣系中等质量的CaO，研究添加剂对渣系的熔点、粘度和脱磷能力的影响，并推荐Li2O作为CaO基钢包 渣系的添加剂。     

Inspired O2 and N2O concentrations in essentially closed circuits

By simulation of the FRC (functional residual capacity), washin of N2O was conceptually separated from uptake at the alveolar-capillary membrane. Data collected by mass spectrometry and pneumotachography during a period of 2 years showed a near-constant body uptake of N2O which makes clinical application of closed circuit N2O--O2 anesthesia simple and safe. The data failed to confirm accelerated washin by higher concentrations of N2O ("the concentration effect"), although there was a concentrating effect according to the law of mass action.     

Solubility and thermodynamic properties of Li2O in LiF-CaF2 melts

Solubility of Li₂O in LiF-CaF₂ melts was studied as a function of temperature, and it was found to increase from 10.6 wt pct at 1058 K to 14.8 wt pct at 1133 K. The liquidus temperature of 4LiF • CaF₂ + Li₂O (saturated) melt was determined to be 1004.5 ± 2.5 K. Activity of Li₂O in the melt was determined as a function of temperature using conventional and Temkin ap-proaches. The partial molar Gibbs energy, enthalpy, and entropy of formation were deduced at the given temperature and composition range studied. The results showed that the system ex-hibits a negative deviation from Temkin's ideality.     

提高锂云母-石灰石烧结法Li2O回收率的途径

根据生产实践,分析了锂云母－石灰石烧结法的提取锂盐生产过程中Ｌｉ２Ｏ损失分布及影响金属回收率的因素,提出了一些改进方法和措施。     

Comparison of the haemodynamic actions of desflurane/N2O and isoflurane/N2O anaesthesia in vascular surgical patients

BACKGROUND: The purpose of this study was to compare heart rate and arterial blood pressure response to desflurane/N2O vs isoflurane/N2O anaesthesia in a randomized clinical trial performed in patients before vascular surgery. METHODS: To evaluate associated changes in the autonomic nervous system with maintenance of anaesthesia, we used power spectral analysis (PSA) of heart rate and blood pressure and measured plasma catecholamine concentrations. Twenty-five patients whose trachea had been intubated after propofol induction were given either desflurane or isoflurane at 1 and 1.5 MAC in N2O (60%) in a random manner. RESULTS: At an anaesthetic depth of up to 1.5 MAC, arterial blood pressure, indices of sympathetic activity derived from PSA, decreased with both anaesthetics, while heart rate and plasma catecholamine concentrations did not significantly change. Plasma renin activity significantly increased at 1.5 MAC anaesthesia in both groups. CONCLUSIONS: We conclude that sympathetic hyperactivity previously reported during desflurane anaesthesia in healthy volunteers is not frequent in clinical practice in elderly vascular surgical patients under desflurane/N2O anaesthesia, since it occurs at an anaesthetic depth which cannot be reached in these patients because of the lowering arterial blood pressure effects of desflurane, which are similar to those of isoflurane.     

放电温度与Li_2O_2充电极化特性关系研究

充电极化过大是制约锂空气电池应用的关键问题之一,这主要源于其放电产物Li2O2低的体相电荷传输能力。本文基于缩短体相电荷传输路径的目的,首次采用控制放电温度的技术降低Li2O2颗粒尺度,研究不同Li2O2的颗粒尺度的充电特性。研究表明,放电温度可以调控Li2O2颗粒特性,高温放电产生的Li2O2倾向在更多的碳基体上形核,颗粒更为细小,可进一步降低充电的电化学反应极化。本研究为降低锂空气电池充电极化提供了一种全新的思路。     

Thermodynamics of O,N, and S in liquid Fe equilibrated with CaO-AI2O3-MgO slags

Nitrogen and S distribution ratios between CaO-Al₂O₃-MgO slags and liquid Fe were measured at 1873 K as a function of Al (or Mg, Ca) content in metal, using CaO, MgO, and A1₂O₃ crucibles. Based on the results for the solubility product of MgO, the equilibrium constant,K _Mg , for the reaction MgO =Mg +O and the first-order interaction parameter,e _O ^Mg (e _Mg ^O ), were estimated to be logK _Mg = -7.8 ± 0.2 ande _O ^Mg = -190 ± 60 (e _Mg ^O = -290 ± 90), respectively. The activities of A1₂O₃ at the slag compositions double-saturated with CaO/MgO, MgO/ MgO A1₂O₃, and MgO Al₂O₃/CaO 2A1₂O₃ components were obtained from the S distribution ratios between slag and metal, coupled with the reported values of sulfide capacities. Nitride capacities were also estimated from the N distribution ratios and the activities of A1₂O₃.