F Xu

Composition design for Laves phase-related BCC-V solid solution alloys with large hydrogen storage capacities

This paper analyzes the alloy composition characteristics with large hydrogen storage capacities in Laves phase-related BCC solid solution alloy systems using the cluster line approach. Since a dense-packed icosahedral cluster A6B7 characterizes the local structure of AB2 Laves phases, in A-B-C ternary system, such as Ti-Cr(Mn, Fe)-V, where A-B forms AB2 Laves phases while A-C and B-C tend to form solid solutions, a cluster line A6B7-C is constructed by linking A6B7 to C. The alloy compositions with large hydrogen storage capacities are generally located near this line and are approximately expressed with the cluster-plus-glue-atom model. The cluster-line alloys (Ti6Cr7)100-xVx (x = 2.5-70 at.%) exhibit different structures and hence different hydrogen storage capacities with increasing V contents. The alloy (Ti6Cr7)95V5 as well as Ti30Cr40V30 with BCC solid solution structure satisfy the cluster-plus-glue-atom model.

Calorimetric study and thermal analysis of [ErY(Ala)4(H2O)8](ClO4)6 (Ala=ALANINE)

A solid complex of rare-earth compounds with alanine, [ErY(Ala)4(H2O)8](ClO4)6 (Ala=alanine), was synthesized, and a calorimetric study and thermal analysis for it was performed through adiabatic calorimetry and thermogravimetry. The low-temperature heat capacity of [ErY(Ala)4(H2O)8](ClO4)6 was measured with an automated adiabatic precision calorimeter over the temperature range from 78 to 377 K. A solid-solid phase transition was found between 99 and 121 K with a peak temperature at 115.78 k. The enthalpy and entropy of the phase transition was determined to be 1.957 Kj mol-1, 16.90 j mol-1 k-1, respectively. Thermal decomposition of the complex was investigated in the temperature range of 40~550°C by use of the thermogravimetric and differential thermogravimetric (TG/DTG) analysis techniques. The TG/DTG curves showed that the decomposition started from 120 and ended at 430°C, completed in three steps. A possible mechanism of the thermal decomposition was elucidated.

Calorimetric study and thermal analysis of berberine sulphate

The heat capacities of berberine sulphate [(C20H18NO4)2SO4·3H2O] were measured from 80 to 390 K by means of an automated adiabatic calorimeter. Smoothed heat capacities, HT-H298.15 and ST-S298.15 were calculated. The loss of crystalline water started at about 339.3±0.2 K, and its peak temperature was 365.8±0.6 K. The peak temperature of decomposition for berberine sulphate was at about 391.4±0.4 K by DSC curve. TG-DTG analysis of this material was carried out in temperature range from 310 to 970 K. TG and DSC curves show that there is no melting in the whole heating process.

Calorimetric study and thermal analysis of [Ho-2(Ala)(4)(H2O)(8)]Cl-6 and [ErY(Ala)(4)(H2O)(8)] (ClO4)(6)

Two solid complexes of rare-earth compounds with alanine, [ho2(ala)(4)(h2o)(8)] cl-6 and [ery(ala)(4)(h2o)(8)] (clo4)(6) (ala = alanine) were synthesized, and a calorimetric study and thermal analysis for the two complexes were performed through adiabatic calorimetry and thermogravimetry. the low-temperature heat capacities of [ho2(ala)(4)(h2o)(8)] cl-6 and [ery(ala)(4)(h2o)(8)] (clo4)(6) were measured with an automated adiabatic precision calorimeter over the temperature range from 78 to 377 k. solid-solid phase transitions were found between 214 k and 255 k with a peak temperature of 235.09 k for [ho2(ala)(4)(h2o)(8)] cl-6, between 99 k and 121 k with a peak temperature of 115. 78 k for [ery (ala)(4) (h2o)(8)] (clo4)(6). the enthalpies and entropies of the phase transitions were determined to be 3.02 kj . mol(-1), 12.83 j . k-1 . mol(-1) for [ho2(ala)(4)(h2o)(8)] cl-6; 1.96 kj . mol(-1), 16.90 j . k-1 . mol(-1) for [ery(ala)(4)(h2o)(8)] (clo4)(6), respectively. thermal decomposition of the two complexes were investigated in the temperature range of 40 similar to 800 degreesc by using the thermogravimetric and differential thermogravimetric (tg/dtg) analysis techniques. the tg/dtg curves showed that the decomposition started from 80 degreesc and ended at 479 degreesc, completed in two steps for [ho2 (ala)(4) (h2o)(8)]cl-6, and started from 120 degreesc and ended at 430 degreesc, completed in three steps for [ery(ala)(4) (h2o)(8)] (clo4)(6), respectively. the possible mechanisms of the thermal decompositions were elucidated.