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The transient heat conduction equation was used as the microscopic model of the Tian-Calvet microcalorimeter. It was verified by comparing simulated and experimental calorimetric curves and used to guide sample cell design for a faster response time, for which it gave the guidelines to minimize the heat flow distance and use a heat flux that is uniform and onto the whole face of the thermopile sensor. The resulting sample cell was disc-shaped with the sample powder placed in it as a thin 0.2 mm layer on a stainless steel base with a wall thickness of 0.5 mm that covered the whole face of the thermopile on which it was placed. The rise time of the heat response curve to a step change in sample temperature, which is the response time for measuring the differential heat released, was 45 s. The response curve from a gas dose returned to the baseline within 400 s, which is the time needed to measure the integrated heat in a pulsed dosage. The accuracy of the heats measured by the calorimeter was verified by comparison with data in the literature on the adsorption of ethanol and ammonia on HZSM-5 and adsorption of methanol and ammonia on SAPO-34. The differential heat of methanol adsorption on SAPO-34 at 333 K and ammonia adsorption on HZSM-5 at 423 K were measured by both the conventional discontinuous procedure and a new continuous procedure. In the continuous procedure, gas was continuously dosed at a very slow flow rate that was kept slow enough for the gas and adsorbate to reach quasi-equilibrium. The continuous procedure has the advantages of high resolution results and a simpler experimental procedure, and a calorimetric curve could be measured within 3 h.

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First-order reversal curve (FORC) diagram, which visualizes the variation of magnetic interaction on a field plane, has been applied to nanocrystalline Ce-Fe-B melt-spinning ribbons. The FORC diagram exhibits different vertical spread along the Hu axis when the applied field is parallel or perpendicular to the ribbon surface. The discrepancy of vertical spread corresponds to different intergranular interactions, which can also be verified by Henkel plot, another method to identify the interactions. The larger vertical spread on the Hu axis along the perpendicular direction is ascribed to the dominance of magnetostatic interaction, while the smaller one along the parallel direction indicates the existence of stronger exchange coupling interaction. The remanence enhancement effect along the parallel direction further confirms the existence of exchange coupling. These indicate that a FORC diagram is a powerful evaluation method for distinguishing different magnetic interactions in permanent magnets. Moreover, Lorentz transmission electron microscopy was used to analyze the magnetic domain structure of nanocrystalline Ce-Fe-B melt-spinning ribbons.

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