An approach for the performance analysis of an uncooled infrared bolometer imager

As an approach for analyzing an uncooled infrared bolometer imager, a method is introduced which supposes that a thermal system is built into the infrared radiation detection mechanism. In this analysis, the bi-directional radiation energy flows between two thermal elements are considered and a radiation thermal conductance between them is defined. Based on the values of the radiation thermal conductances and conventional material thermal conductance, an equivalent thermal circuit for a bolometer detector element is extracted. Calculations were carried out using software written in visual C++. The analysis shows a Noise Equivalent Temperature Difference (NETD) of 50 mK is obtained as a typical value, assuming that no additional noise other than temperature fluctuation noise exists, and that the NETD becomes better as the system time constant built into the equivalent thermal circuit increases.     

Three-dimensional GaN-Ga2O3 core shell structure revealed by x-ray diffraction microscopy

In combination of direct phase retrieval of coherent x-ray diffraction patterns with a novel tomographic reconstruction algorithm, we, for the first time, carried out quantitative 3D imaging of a heat-treated GaN particle with each voxel corresponding to 17 x 17 x 17 nm3. We observed the platelet structure of GaN and the formation of small islands on the surface of the platelets, and successfully captured the internal GaN-Ga2O3 core shell structure in three dimensions. This work opens the door for nondestructive and quantitative imaging of 3D morphology and 3D internal structure of a wide range of materials at the nanometer scale resolution that are amorphous or possess only short-range atomic organization.     

Effect of interference pattern on femtosecond laser-induced ripple structure

Combined structures composed of a micron-sized periodic structure and a nano-sized quasi-periodic ripple structure were generated by a single process of multiple shots of an interfering femtosecond laser. The former structure was generated by an interference pattern and controlled by a number of beams. The latter structure was generated by a multiple shot method. As a result, multiple periodic structures were generated. The periodicity of the structures was analyzed by two-dimensional (2D) fast Fourier transform (FFT). The most probable period of ripple structure was downsized to 177 nm by restricting irradiated region by a TM wave interference pattern. The smallest period was 105 nm. The dispersion angle of a ripple decreased to about 50%. The period and direction of the ripples were for a first time controlled by using interference.     

Luminescent Polymer Consisting of 9,12‐Linked o‐Carborane

The synthesis of novel luminescent polymer containing p‐phenylene‐ethynylene and 9,12‐linked o‐carborane units alternately in the main chain is reported. The obtained polymer exhibits intense blue photoluminescence, providing the first insights into the optical properties of a 9,12‐disubstituted o‐carborane dye.  π‐Conjugated substituent at 9 and/or 12‐positions in o‐carborane is electrically independent, and both the HOMO and the LUMO levels slightly increase, whereas LUMO of the π‐conjugated substituent at 1 and/or 2‐positions in o‐carborane decrease.  Thus, it is deduced that polymers consisting of the 9,12‐linked o‐carborane unit are able to be applied as light‐emitting materials.

     

Excitation Photon Energy Dependent Relaxation Processes of the Photoexcited States in Wide Gap MX-Chain Complexes

Abstract

Photo-induced absorption (PA) spectra of [Pt (en)₂] [Pt (en)₂X₂] (SO₂)₂. 6H₂O (X=Cl and Br) have been measured. Large excitation photon energy dependent changes were found in the features of the PA spectra. The excitation photon energy dependences are considered to be due to the difference between the relaxation processes of the charge transfer excitons and those of the higher energy excited states. Several new PA bands have been found.     

Stochastic reaction diffusion equations on an infinite interval with reflection

We consider a time evolution of random fields with non-negative values on the real line. Such evolution is described by an infinite dimensional stochastic differential equation of Skorokhod's type, which is a stochastic partial differential equation (SPDE) of parabolic type with reflection. We shall show the existence of the solution, and its uniqueness when the diffusion coefficient is constant.     

The Effect of Intramolecular Hydrogen Bonding on the Intensity and Frequency of OH Stretching Band in Alicyclic Substances

The change in intensity and frequency of O-H stretching band upon intramolecular hydrogen bonding was sufficiently examined for various proton acceptors of many alicyclic substances. The order of proton acceptors to bring about the intensity increase of constant degree is: Some discussions are given on these.