Phase transition behaviors of thin film of n-alkyl alcohols (1-heptadecanol and 1-octadecanol) with sample masses from 2 μg to 1 mg were investigated by the high sensitive DSC. The shape of endothermic peaks changed at 0.1 and 0.03 mg for both alcohols, accompanied with the transition temperature shift to the lower side. The transition enthalpy values of the γ-α transition and the melting for 1-octadecanol were determined as the average over the samples larger than 0.05 mg, the γ-α transition (329.6 K, 23.9 kJ/mol), and the melting (330.1 K, 42.5 kJ/mol). The relationship between thermodynamic quantities and alkyl carbon number showed the odd-even effect for the transition temperature and the transition enthalpies for both the solid phase transition and the melting. The entropy increment at one methylene unit for the melting was 9.6 J/Kmol, showing a good correlation with ΔS = Rln 3 = 9.13 J/Kmol. The morphological observation of crystals at 0.1 and 0.005 mg samples by a differential interference contrast microscope and an atomic force microscope indicated the coexistence of polycrystalline blocks (> 20 μm) and plate shaped crystals (< 20 μm) for the 0.1 mg sample, and only plate shaped crystals (< 20 μm) for the 0.005 mg sample. These facts suggested that the former crystals showed thermal behavior of bulk sample, and the latter crystal showed the effect of surface on transition temperatures of thin sample.

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The challenge of determining the last two digits of absolute zero temperature attracted several groups of researchers around the world in the first half of the 20th century. It is little known that Japanese researchers, Jiro Oishi and Masao Kinoshita, were the ones who successfully settled the dispute over these two digits. Their work played a key role in defining the zero point on the thermodynamic temperature scale, and thus later in defining the unit of thermodynamic temperature, the kelvin, in terms of the absolute zero and the triple point of water. This current definition of kelvin is scheduled to be redefined based on the Boltzman constant. On the occasion of this turning point of the definition of the kelvin, it may be timely to reflect on the historic milestone work of Oishi and Kinoshita. The background and current status for changing the definition are also described.

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Lipids are the major substance in biological membrane. They also make an important role for industrial applications such as food, pharmaceutical and cosmetics. Here, we have reviewed the physical chemistry of lipids, especially, highlighted to triacylglycerols (TAGs) and phospholipids. In the TAGs part, the thermal and structural properties of PPP and POP, the typical TAGs, have been focused on. The complicated polymorphism is present in TAGs. In order to determine polymorphs, time-resolved synchrotron radiation X-ray diffraction measurement and differential scanning calorimetry (DSC) under the same conditions, simultaneous or even though not simultaneous, is effective. As for phospholipid part, at first, the type of phospholipid and relationship between phospholipid and bio-membrane has been introduced. Secondly, crystal structure of phospholipid has also been introduced. Thirdly, the polymorphism and phase transitions of phospholipids under excess water, namely hydrated membrane state, have been highlighted. DSC data and its analysis, transition temperature, transition enthalpy and conformation entropy, have been explained and discussed. Finally, an interesting topic about the relationship between phase transition and life activity has been introduced.

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Recent studies on heat capacity calorimetry of nanomagnets including single-molecule magnets are reviewed. Single-molecule magnet is the name of paramagnetic molecules showing superparamagnetic behavior and blocking of magnetization reversal despite the absence of magnetic long-range order. Heat capacity calorimetry plays an important role in the characterization of this class of nanomagnets, not only for determination of spin energy levels and magnetic anisotropy but also for confirming the absence of magnetic long-range order. In another view, single-molecule magnets serve as a playground for the demonstration of kinetic selection rule dominating thermal excitations, thanks to an additional control parameter of external magnetic field which can open/close relaxation channels relating to transverse or longitudinal manner of application. Related nanomagnets covering single-chain magnets and antiferromagnetic spin rings are also discussed. The Zeeman-split spin levels of the latter show avoided crossings due to the off-diagonal matrix elements of magnetic anisotropy, and it is revealed that heat capacity calorimetry is useful for understanding such level systems.

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