Temperature Characteristics of Vibrating Type Sensor Using Micromachined Optical Fiber-Tip

An optical sensor using a quartz core microcantilever was fabricated by etching clad layer from optical fiber. The temperature dependence of the resonance frequency of this sensor was measured in atmosphere and water. The temperature coefficient of the resonance frequency in water was 1.3×10⁻³/°C, which was about one order larger than that (2.3×10⁻⁴/°C) in atmosphere. This was caused by increase of additional mass due to temperature dependence of the viscosity of water, while, the increase of the resonance frequency in atmosphere was caused by temperature dependence of Young’s modulus of the quartz core. These results were evaluated theoretically using a “string-of-beads” model.     

Multiscale model for moisture transport with adsorption phenomenon in concrete materials

Abstract

We consider a new two-scale problem which is given as a mathematical model for moisture transport arising in a concrete carbonation process. In research for moisture transport, it is a crucial step how to describe the relationship between the relative humidity and the degree of saturation, mathematically. Here, we have proposed the two-scale model consisting of the diffusion equation for the relative humidity in a macro domain and the free boundary problems describing the relationship in infinitely micro domains. Accordingly, the structures of the micro domains are unknown in our model. This is a significant feature of our new model to emphasize. The aim of this paper is to establish local existence in time and uniqueness of a solution to the model.     

Femtosecond intermolecular electron transfer in condensed systems

We have investigated the ultrafast intermolecular electron transfer (ET) from an electron-donating solvent (aniline (AN) or N, N-dimethylaniline (DMA)) to an excited dye molecule (oxazines (Nile blue and oxazine 1) or coumarins). A non-exponential time dependence was observed in AN and can be explained by solvent reorientation and nuclear motion of the reactants. However, in DMA, a single exponential process was observed for Nile blue (160 fs) and oxazine 1 (280 fs), which can be explained by assuming that the rate of ET is limited mainly by ultrafast nuclear motion. A clear substituent effect on intermolecular ET was observed for the 7-aminocoumarins. When the alkyl chain on the 7-amino group is extended and a hexagonal ring with the benzene moiety is formed, the rate of ET is reduced by three orders of magnitude. This effect can be explained by a change in the free energy difference of the reaction and by the vibrational motion of the amino group.     

Mathematical model for hysteresis phenomenon in moisture transport of concrete carbonation process

From civil engineering point of view it is very important to construct and analyze a mathematical model for a mechanism of concrete carbonation process. On this subject there are several mathematical results concerned with a one-dimensional model, in which hysteresis effects are neglected. Our aim is to give a model with hysteresis effects appearing in carbonation process. In this paper, as the first step of this research we focus only on moisture transport in the process and propose an initial boundary value problem for a system of partial differential equations as a mathematical model. Also, we give results on the existence of a solution to the problem, globally in time and the uniqueness in only one-dimensional case without proofs.     

Prediction of molecular flexibility in halogenated alkanes via fractal dimensionality

The topological connectedness and experimentally determined boiling point for each of a series of halogenated normal alkane molecules were used to derive fractal dimensionalities of these molecules by a simplified version of the method of Rouvray and Pandey. The results, which relate to the time-averaged molecular conformations of the species in the bulk liquid phase, were then used to obtain estimates of the flexibility of the molecules in question. The effects of the halogen atoms are pronounced and reveal a number of interesting trends. Such analysis is of particular value in the medical context, since perfluorinated alkanes and other perfluorinated species are now being employed widely in medical operations as substitutes for body fluids.     

A system of evolution equations for non-isothermal phase transitions

We propose and study a system of evolution equations. This is an abstract formulation of problems arising in non-isothermal phase transitions. We consider time-dependent constraints on the unknown functions. Thus the problem yields a system of parabolic variational inequalities. We prove the existence of a solution in a general framework, and then apply the abstract result to some models of phase transitions.     

Far infrared reflection spectra of layered semiconductors

Far infrared reflection and Raman spectra of InSe were measured at 5, 77 and 300 K. Phonon frequencies obtained by reflection spectra were well explained by two-point phonon combination. The crystal structure of-type was confirmed at low temperature. Ion blocking analysis supported also no change of phase by temperature in this semiconductor.     

Large time behavior of a solution of carbon dioxide transport model in concrete carbonation process

In [7] we show the global existence and uniqueness of a solution of carbon dioxide transport model in concrete carbonation process. This model is governed by a parabolic-type equation which has a non-local term depending on the unknown function itself. In this paper, we show the large time behavior of that solution.