Temperature-Squared Terms in the Heat Capacities of 3He Fluid Films

Recently the heat-capacity of a two-dimensional Fermi fluid is theoretically shown by Misawa to vary as C(T)= ₀ T– ₂ T ² as a function of temperature T at low temperature, where ₀ and ₂ are constants. To check this prediction our measured heat-capacities of three different systems are reexamined, i.e., the first-layer and second-layer ³ He fluid films adsorbed on a bare graphite surface and monolayer ³ He films floated on a ⁴ He thin film adsorbed on graphite. The measured heat-capacities are reproduced well by the predicted formula. The areal-density dependence of ₂ on each system also coincides with Misawa's prediction if the second order perturbation treatment by Fujimoto is adopted as the self-energy calculation.     

Graphene's Latest Cousin: Plumbene Epitaxial Growth on a “Nano WaterCube”

While theoretical studies predicted the stability and exotic properties of plumbene, the last group‐14 cousin of graphene, its realization has remained a challenging quest. Here, it is shown with compelling evidence that plumbene is epitaxially grown by segregation on a Pd_1?xPb_x(111) alloy surface. In scanning tunneling microscopy (STM), it exhibits a unique surface morphology resembling the famous Weaire–Phelan bubble structure of the Olympic “WaterCube” in Beijing. The “soap bubbles” of this “Nano WaterCube” are adjustable with their average sizes (in‐between 15 and 80 nm) related to the Pb concentration (x < 0.2) dependence of the lattice parameter of the Pd_1?xPb_x(111) alloy surface. Angle‐resolved core‐level measurements demonstrate that a lead sheet overlays the Pd_1?xPb_x(111) alloy. Atomic‐scale STM images of this Pb sheet show a planar honeycomb structure with a unit cell ranging from 0.48 to 0.49 nm corresponding to that of the standalone 2D topological insulator plumbene.     

Adhesion Force Measurements of Polymer Particles by Detachment Field Method

The adhesion force distributions of polymer particles to aluminum substrates were measured by the detachment field method. Polymer particles with conducting surface treatment were used for the measurements.Further the conventional detachment field method was modified to be applicable to the adhesion force measurements of a single particle. The adhesion force of the polymer particles increased with an increase in relative humidity. The surface roughness of the substrate influenced the adhesion forces of particles significantly. The influence of the CF4 plasma treatment of the polymer particles and thin layer coating of the substrate surface on the adhesion forces of the polymer particles was also studied, and factors affecting adhesion forces of polymer particles are discussed.     

Low Amplified Spontaneous Emission Threshold from Organic Dyes Based on Bis‐stilbene

Advanced organic laser dyes exhibiting high solubility and bipolar behavior are developed based on a structure combining bis‐stilbene with carbazole (BSBCz). The materials show high photoluminescence quantum yields and large radiative rate constants in solutions, crystals, and blend and neat films. The introduction of alkyl groups significantly improves the solubility of BSBCz, and solution‐processed films of the alkyl‐substituted derivatives exhibit amplified spontaneous emission thresholds as low as 0.59 µJ cm^?2, which is comparable to those of vacuum‐deposited BSBCz films. On the other hand, cyano‐substitution on BSBCz (BSBCz‐CN) increases electron‐accepting properties, resulting in a bathochromic shift of the emission wavelength and improved bipolar behavior. In a BSBCz‐CN‐doped film, a low ASE threshold of 0.63 µJ cm^?2 is achieved, which is one of the lowest values for organic laser dyes with green emission. In addition, organic light‐emitting diodes based on BSBCz‐CN neat films exhibit external quantum efficiencies of 1.8% and could withstand injection of high current densities of up to 500 A cm^?2 under pulse operation. These properties along with low excited‐state absorption cross sections make these materials an outstanding addition to the existing library of organic laser dyes, especially for consideration in electrically pumped lasers.     

Self‐structured serrated edges of chemically oxidized poly(dimethylsiloxane) disks

Serrated structures on a micrometer scale were spontaneously formed along the edge of a poly(dimethylsiloxane) (PDMS) disk using the following procedure. First, a drop of PDMS prepolymer was placed on a glass slide, followed by vulcanization. Second, the obtained PDMS disk was soaked in a mixture of sulfuric acid and nitric acid to form a serrated structure. Consideration of the mechanism of the structure formation was based on the following results. (1) The acid oxidized the PDMS surface, which was then swollen with the acid mixture or water to form wrinkles. (2) The wrinkle wavelength depended on the thickness of the PDMS film. (3) The thickness of the PDMS disk varied near its edge because the meniscus of the drop of the PDMS prepolymer was retained after the vulcanization. These results suggest that the thickness gradient of the PDMS disk led to the spontaneous formation of a serrated edge structure. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40767.     

Development of a novel glue consisting of naturally-derived biomolecules: citric acid and human serum albumin

A novel glue consisting of human serum albumin (HSA) and citric acid derivative (CAD) was developed where the glue is named as CAD-A glue. In this adhesive, CAD works as a crosslinking reagent of HSA. For preparing crosslinking reagent CAD, using citric acid as a starting material, three carboxyl groups of a citric acid were modified with N-hydroxysuccinimide in the presence of 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride. From 1H-NMR spectrum, CAD with three active ester groups in a molecule was successfully synthesized with a high yield (more than 80%). The boding time of CAD-A glue to collagen-based casing was saturated within 15 minutes. The bonding strength of this glue to collagen-based casings increased with increasing of HSA concentration. The maximum bonding strength of CAD-A glue was a slightly low level compared to the bonding strength of cyanoacrylate adhesive and was 9 times higher than that of fibrin glue. The CAD-A glue showed excellent biocompatibility and high ability of wound closure similar to that of cyanoacrylate-based adhesive when glues were applied to the mouse skin. These results suggested that this developed adhesive had both tissue compatibility and bonding strength for use in clinical field.     

Photocurrent generators derived from non-covalently assembled soft-matter molecular system

It is rather difficult to design a multilayer photocurrent generator system on the ITO electrode, however, the preparation of thin film with high surface concentration of donor units is indispensable in order to achieve high conversion efficiency. The polymer film of porphyrin bearing pyroles on the electrode was prepared by the potential sweep method. It was indicated that the self-aggregation can be suppressed by encapsulation of the porphyrin unit in the cavity of macro-cyclic host molecule, cyclodextrin. We established the non-equilibrium host-guest system with porphyrins and cyclodextrins for the first time. The photocurrent density and the quantum yield in the porphyrin-cyclodextrin system are remarkably improved. It was demonstrated that the high quantum yield, perhaps 25 times larger, arises from the isolation of the porphyrin unit by cyclodextrin through host-guest interactions.     

Unsaturated phosphatidylethanolamine as effective synergist in combination with alpha-tocopherol

The effects of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) on the oxidation of bonito oil triacylglycerol (TAG) were examined under the absence or presence of alpha-tocopherol. Synthesized PC or PE having saturated and unsaturated fatty acids in known position were used in this study. Unsaturated PC and PE promoted TAG oxidation under the absence of alpha-tocopherol. On the contrary, unsaturated PE showed synergistic antioxidant effect with alpha-tocopherol, while PC had little effect. The strongest synergistic effect was found by 1-palmitoyl (16:0, PA)-2-docosahexaenoyl (22:6n-3)-PE, followed by 1-PA-2-arachidonyl (20:4n-6)-PE, 1,2-dioleoyl (18:1n-9)-PE, and 1-PA-2-linoleoyl (18:2n-6)-PE, respectively.