Surface-active particles with microstructured surfaces

Interfaces adsorbing solid particles have recently attracted great attentions in the field of materials science, because they are useful as templates of well-ordered particle arrays or of microstructured hollow spheres. The solid particles are adsorbed at the interfaces and form self-assembled structures when the particles have suitable wettability to both fluids. Here, we show theoretically how the microstructure on the particle surface affects their adsorption properties. The physical properties of the interface adsorbing a particle will be described with consideration for surface area magnification due to the microstructure. The microstructure on the surface changes drastically the wettability and the equilibrium position of the adsorbed particle and prevents the particle from adsorption at the interface. The range of the interfacial tensions at which the particle is adsorbed becomes narrower with the increase of the magnification. On the other hand, the particle which is partially covered with the microstructured surface is adsorbed firmly at the interface in an oriented state. We should consider not only the interfacial tensions but also the surface structure to control the adsorption behavior of the particle.     

Hydrodynamic interactions in the structural fluctuation of a ternary amphiphilic system C12E5/water/ n-octane

Dynamical fluctuations of microemulsion and lamellar structures in a ternary amphiphilic system C₁₂E ₅/water/n-octane are studied by means of neutron spin echo spectrometry. The decay rate of the time correlation of the concentration was analyzed in terms of a theory (M. Nonomura, T. Ohta, J. Chem. Phys. 110, 7516 (1999)), in which both van Hove and hydrodynamic interactions are considered. The result shows that the time correlation function is expressed mostly by a single exponential determined exclusively by hydrodynamic interactions. Received 1 December 1999 and Received in final form 12 March 2001     

Drag coefficient of a liquid domain in a two-dimensional membrane

Using a hydrodynamic theory that incorporates a momentum decay mechanism, we calculate the drag coefficient of a circular liquid domain of finite viscosity moving in a two-dimensional membrane. We derive an analytical expression for the drag coefficient which covers the whole range of domain sizes. Several limiting expressions are discussed. The obtained drag coefficient decreases as the domain viscosity becomes smaller with respect to the outer membrane viscosity. This is because the flow induced in the domain acts to transport the fluid in the surrounding matrix more efficiently.     

GPU-based single-cluster algorithm for the simulation of the Ising model

We present the GPU calculation with the common unified device architecture (CUDA) for the Wolff single-cluster algorithm of the Ising model. Proposing an algorithm for a quasi-block synchronization, we realize the Wolff single-cluster Monte Carlo simulation with CUDA. We perform parallel computations for the newly added spins in the growing cluster. As a result, the GPU calculation speed for the two-dimensional Ising model at the critical temperature with the linear size L = 4096 is 5.60 times as fast as the calculation speed on a current CPU core. For the three-dimensional Ising model with the linear size L = 256, the GPU calculation speed is 7.90 times as fast as the CPU calculation speed. The idea of quasi-block synchronization can be used not only in the cluster algorithm but also in many fields where the synchronization of all threads is required.     

Thermoelectric power of antiferromagnetic RIn3 compounds

The thermoelectric power (TEP) has been measured from 2.2 to 300 K for antiferromagnetic compounds, CeIn₃, NdIn₃, SmIn₃, GdIn₃ and (Ce_1−xLa_x)In₃ with x = 0.1 and 0.2. The effects of the antiferromagnetic order were observed on the TEP of these compounds below T_N. The observations are explained by the antiferromagnetic band gap formation theory proposed by Abel'skii.     

Measurements of210Pb and210Po in Japanese human hair

²¹⁰Pb and²¹⁰Po in human hair have been measured to serve as an aid in order to estimate the dietary intake and body burden of these radionuclides of Japanese. The²¹⁰Po concentrations found in 83 hair samples were ranging from 4.0 to 59.3 mBq/g with a mean (median) value of 18.2±12.2 (14.9) mBq/g as compared to the²¹⁰Pb concentrations from 0.7 to 6.5 mBq/g with a mean (median) value of 2.3±1.1 (2.0) mBq/g. The²¹⁰Po/²¹⁰Pb activity ratios (mean: 8.7±5.1, median: 7.1) were surprisingly higher compared with the available literature value of about 2. The high concentration of²¹⁰Po in human hair of Japanese may be due to the ingestion of animal protein mainly in the form of seafood.     

The 19th International Display Workshops (IDW ’12), Japan

With the benefit of hindsight we can see that there is a pre-history to the field of discotic liquid crystals: theoretical and experimental papers that predate the 1977 paper in Pramana by Chandrasekhar, Sadashiva and Suresh. However, what is often forgotten is how boldly adventurous the Pramana paper was and how remote the chance seemed that anything important would be learnt from reinvestigating the esters of hexahydroxybenzene. By 1977 although there was some evidence for the possibility of making liquid crystals based on disc-shaped molecules, the evidence against such a possibility was also very strong.     

Effects of the temperature and the pressure on the intermediate valence of Ce(In1−xSnx)3

The curve of the lattice constant of samples Ce(In_1-xSn_x)₃ plotted as a function of the composition x deviates from the linear Vegard's law; the deviation is found to be much more eminent at liquid N₂ temperature than at room temperature. Effects of the pressure on the electrical resistivity was found to be very large for a sample with a composition x = 0.5 which is near to the critical value of the occurence of the intermediate valence state of Ce atoms. The atomic volume of Ce atoms is seen to play an important role for the occurence of the intermediate valence state.