Dehydrogenation of cycloalkanes over noble metal catalysts supported on active carbon

Dehydrogenation of decalin to naphthalene through tetralin and that of dicyclohexyl to biphenyl through phenylcyclohexane with Pt/C and Pd/C was investigated mainly under the liquid film state, in which the catalyst was just wet but not suspended and covered with a thin film of liquid substrate. To improve the catalytic activities, the effects of the addition of tellurium into Pd/C were investigated to reveal that the combination of tellurium, palladium and conjugated systems produced during the dehydrogenation of cycloalkames was important to the improvement of the activities.     

Direct importance estimation for covariate shift adaptation

A situation where training and test samples follow different input distributions is called covariate shift. Under covariate shift, standard learning methods such as maximum likelihood estimation are no longer consistent—weighted variants according to the ratio of test and training input densities are consistent. Therefore, accurately estimating the density ratio, called the importance, is one of the key issues in covariate shift adaptation. A naive approach to this task is to first estimate training and test input densities separately and then estimate the importance by taking the ratio of the estimated densities. However, this naive approach tends to perform poorly since density estimation is a hard task particularly in high dimensional cases. In this paper, we propose a direct importance estimation method that does not involve density estimation. Our method is equipped with a natural cross validation procedure and hence tuning parameters such as the kernel width can be objectively optimized. Furthermore, we give rigorous mathematical proofs for the convergence of the proposed algorithm. Simulations illustrate the usefulness of our approach.     

Synthesis of amphiphilic polysiloxanes and their properties for formation of nano-aggregates

In this study, we prepared amphiphilic polysiloxanes by introduction of hydrophobic and hydrophilic parts into a water-soluble poly(3-aminopropyl)siloxane. Fatty acid (lauroyl, myristoyl, palmitoyl, and stearoyl) chlorides and gluconolactone were employed as the reactants for the hydrophobic and hydrophilic parts, respectively. The reaction of the poly(3-aminopropyl)siloxane with fatty acid chlorides was performed in water/DMF, followed by the reaction with gluconolactone in DMSO, giving the corresponding amphiphilic polysiloxanes. The results of the NMR spectra, SEM observations, and DLS measurements indicated the formation of nano-aggregates from the amphiphilic polysiloxanes in water. These analytical data also suggested that the structures and functionalities of the hydrophobic parts affected the formation properties of the nano-aggregates.     

Totally Umbilic Isometric Immersions and Curves of Order Two

In this paper we study submanifolds by use of extrinsic shapes of some curves having points of proper order 2, and give a condition that they are totally umbilic. This gives an extension of Nomizu-Yano’s result in [7] on a characterization of extrinsic spheres. The second author is partially supported by Grant-in-Aid for Scientific Research (C) (No. 17540072), Ministry of Education, Science, Sports, Culture and Technology.     

Analysis of heat conduction in a rarefied gas at rest with a temperature jump at the boundary by consistent-order extended thermodynamics

In the context of the first- and second-order theories of consistent-order extended thermodynamics, a systematic approach is established for analyzing the temperature jump at the boundary through studying one-dimensional stationary heat conduction in a rarefied gas at rest. Thereby an approach to the free boundary-value problem in general is explored. Boundary values of temperature are assumed to be in the form of power expansion with respect to the Knudsen number, based on which analytical expressions of the temperature jump aswell as entropy production at the boundary are derived explicitly. Dependencies of these two boundary quantities on both the Knudsen number and accommodation factor are also extensively discussed. The present analysis is expected to be the basis for the study of higher-order theories of consistent-order extended thermodynamics.      

Magnetic and superconducting properties of a pressure-induced superconductor CePd5Al2

We investigated the magnetic and electronic properties of an antiferromagnet and pressure-induced superconductor CePd₅Al₂ by measuring the magnetization and de Haas-van Alphen effect, together with the electrical resistivity under pressure and magnetic field. Magnetic measurements including the high field magnetization at 1.3 K reveal several magnetic transitions and quite complex magnetic phase diagram of this compound. Electrical resistivity measurements have been performed using diamond anvil cell up to 12 GPa for the magnetic fields and [1 0 0]. The upper critical field in superconductivity is anisotropic between and [1 0 0] in the tetragonal structure, reflecting the quasi-two dimensional electronic state.