Spectroscopic Properties of Morin in Various CH3OH–H2O and CH3CN–H2O Mixed Solvents

The specific fluorescence properties of morin (3,2′,4′,5,7‐pentahydroxyflavone) were studied in various CH₃OH–H₂O and CH₃CN–H₂O mixed solvents. Although the dihedral angle is large in the S₀ state, morin has an almost planar molecular structure in the S₁ state owing to the very low rotational energy barrier around the interring bond between B and the A, C ring. The excited state intramolecular proton transfer (ESIPT) at the S₁ state cannot occur immediately after excitation, S₁ → S₀ fluorescence can be observed. Two conformers, Morin A and B have been known. At the CH₃OH–H₂O, Morin B will be the principal species but at the CH₃CN–H₂O, Morin A is the principal species. At the CH₃OH–H₂O, owing to the large Franck–Condon (FC) factor for S₂ → S₁ internal convernal (IC) and flexible molecular structure, only S₁ → S₀ fluorescence was exhibited. At the CH₃CN–H₂O, as the FC factor for S₂ → S₁ IC is small and molecular structure is rigid, S₂ → S₀ and S₁ → S₀ dual fluorescence was observed. This abnormal fluorescence property was further supported by the small pK₁ value, effective delocalization of the lone pair electrons of C(2′)–OH to the A, C ring, and a theoretical calculation.     

Resorcin[4]arene-based anion receptors with four phenylurea substituents

Cavitand-based anion receptors were developed by the introduction of four phenylurea moieties on the upper rim of a resorcin[4]arene. Their binding properties for various anions were investigated in DMSO-d₆ using ¹H NMR spectroscopic methods, and the high 1:1 binding affinity for carboxylates was observed due to hydrophobic as well as charge-dipole interactions between host and guest.     

Interferometric phase-only optical encryption system that uses a reference wave

An improved image decryption system is proposed that is based on phase-encoded images and the principle of interference and uses a reference wave. A novel technique for generating intensity patterns from the decrypted phase information consists simply of interfering a reference wave with the wave passing through the encrypted image and a phase-only decrypting key. Optical experiments have confirmed the proposed technique as a simple and robust architecture for optical encryption.     

Bi3.25La0.75Ti3O12 (BLT) nanotube capacitors for semiconductor memories

We report results of fabrication and examination of Bi_3.25La_0.75Ti₃O₁₂ (BLT) ferroelectric nanotubes. BLT nanotubes are suggested for developing 3D ferroelectric nanotube capacitors which could be used in high-density memory applications. BLT nanotubes were prepared by template-wetting process using polymeric sources where anodic aluminum oxide had been used as a template. After annealing, tubular BLT structures were crystallized inside the pores of the template. By selective etching of the template, released BLT nanotubes have been obtained. Crystallization and nucleation of the nanotubes were analyzed by XRD and FE-SEM techniques.     

Analysis of current loss from a series-parallel combination of dye-sensitized solar cells using electrochemical impedance spectroscopy

Dye-sensitized solar cells (DSCs) have been proposed as a substitute for silicon crystalline solar cells which have a high manufacturing cost but it is still difficult to fabricate highly efficient DSC module assemblies. Therefore, in this work, an externally connected module assembly was investigated for industrial applications of DSCs. The equivalent circuit of a DSC was determined using typical electrical components and the cause of a current loss in the parallel connection was analyzed using electrochemical impedance spectroscopy. Also, an externally connected module has been constructed using 50 DSCs, where each cell has an active area of 8 cm² (4.62 cm × 1.73 cm) and a conversion efficiency of 4.21% under 1 sun illumination (P_in of 100 mW/cm²). As a result, the externally connected DSC module assembly has an output of 7.4 V and 200 mA, and shows stable performance, with an energy conversion efficiency of 4.44% under 0.45 sun illuminations.     

An accurate formula for the reconstruction of conductivity inhomogeneities

We carefully derive accurate asymptotic expansions of the steady-state voltage potentials in the presence of a finite number of diametrically small inhomogeneities with conductivities different from the background conductivity. We then apply these accurate asymptotic formulae for the purpose of identifying the location and certain properties of the shape of the conductivity anomaly. Our designed real-time algorithm makes use of constant current sources. It is based on the observation in both the near and far field of the pattern of a simple weighted combination of the input currents and the output voltages. The mathematical analysis provided in this paper indicates that our algorithm is with a very high resolution and accuracy.     

Measurements and removal of cerenkov light generated in scintillating fiber-optic sensor induced by high-energy electron beams using a spectrometer

In this study, we measured scintillating and Cerenkov lights generated in a scintillating fiber-optic sensor using highenergy electron beams and a spectrometer. The spectrum of Cerenkov light generated in a plastic optical fiber was measured with a spectrometer and the intensities of Cerenkov light were measured for irradiated lengths of the plastic optical fiber by integrating the photon counts at every wavelength of the spectrum. The intensities of Cerenkov and scintillating lights were also characterized as a function of the incident angle of an electron beam from a clinical linear accelerator (CLINAC). To minimize or remove Cerenkov light, a subtraction method was employed using a background optical fiber.     

Practical image hiding method using a phase wrapping rule and real-valued decoding key

We propose a practical image hiding method using phase wrapping and real-valued decoding key. A zero-padded original image, multiplied with a random-phase pattern, is Fourier transformed and its real-valued data denotes an encoded image in the embedding process. The encoded image is divided into two phase-encoded random patterns which are generated based on the phase wrapping rule. The imaginary part and the real part of these phase-encoded random patterns are used as a hidden image and a decoding key, respectively. A host image is then made from the linear superposition of the weighted hidden image and a cover image. The original image is simply obtained by the inverse-Fourier transform of the product of the host image and the decoding key in the reconstruction process. The embedding process and the reconstruction process are performed digitally and optically, respectively. Computer simulation and an optical experiment are shown in support of the proposed method.