This paper reports the hydrogen storage properties of a ternary hydride system, LiAlH4−MgH2−LiBH4 (molar ratio 1:1:1), both undoped and doped with TiF3 addition. It was found that there is a mutual destabilization among the three hydrides. This new ternary system possesses superior hydrogen desorption properties compared with the unary components (LiAlH4, MgH2, and LiBH4) or binary mixtures of those components (LiAlH4−MgH2, LiAlH4−LiBH4, and MgH2−LiBH4). On doping with TiF3, the system starts to release hydrogen at 60 °C and completes dehydrogenation below 400 °C. Three major dehydrogenation steps were observed in the undoped and TiF3-doped systems, which corresponds to the decomposition of LiAlH4, MgH2, and LiBH4, respectively. X-ray diffraction (XRD) measurements on the as-dehydrogenated samples were executed to identify the dehydrogenation pathway. The third step decomposition enthalpy of the doped system was determined by pressure−composition−temperature (PCT) measurements and the van't Hoff equation to be 54 kJ/mol H2, which is smaller than that of LiBH4 alone (74 kJ/mol H2). In addition, the TiF3-doped system is partially reversible at moderate temperature and pressure (4 MPa, 400 °C) with good cycling. The enhancement of the hydrogen sorption properties was attributed to the formation of intermediate compounds, including Li−Mg, Mg−Al, and Mg−Al−B alloys, upon dehydrogenation, which change the thermodynamics of the reactions through altering the de/rehydrogenation pathway. The TiF3 component in the doped system plays a catalytic role through the formation of Ti-containing and F-containing catalytic species, which strengthens this interaction and thus further improves the dehydrogenation and hydrogenation of this system.
Objective To investigate clinical distribution and drug sensitivity of infectious pathogens in our wards for hematology malignancies. Methods Drug sensitivity tests of bacteria were performed by Kirby-Bauer method, 56 strains of pathogens were isolated from all detected samples. Results The results showed that the composition ratio of Gram-negtive bacteria, Gram-positive bacteria was 69.64%, 30.36%. In decreasing frequency, Escherichia coli (37.50%), Klebsiella pneumoniae (10.71%). All of staphylococcies were resistant to meticillin, and sensitive to vancomycin. Conclusion This study indicates that Gramnegative bacteria remain the predominant pathogens in microorganisms causing bloodstream infections for hematological malignancies at Huashan Hospital. The incidence of Escherichia coli is the highest. All of staphylococcies were resistant to meticillin.
Key words:
Hematologic neoplasms; Bacterial infection; Blood; Drug sensitivity
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