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Suppression of thermal noise in non-Markovian random velocity field

Journal of Statistical Mechanics: Theory and Experiment Volume 2016

We study the diffusion of Brownian particles in a Gaussian random velocity field with short memory. By extending the derivation of an effective Fokker–Planck equation for the Lanvegin equation with weakly colored noise to a random velocity-field problem, we find that the effect of thermal noise on particles is suppressed by the existence of memory. We also find that the renormalization effect for the relative diffusion of two particles is stronger than that for single-particle diffusion. The results are compared with those of molecular dynamics simulations.

Creators : Ueda Masahiko Publishers : IOP Publishing Date Issued : 2016-02-25

Controlled formation of pseudoisocyanine J-aggregates in the interlayer space of synthetic saponite.

Applied Clay Science Volume 140

In presented work dye assemblies with J-type intermolecular coupling, which are well recognized not only for their exciton transport but also for hole and electron transport properties were investigated. The use of materials consisting of J-type dye assemblies can be significantly enhanced if their photonic properties can be controlled by some external stimuli. For these reasons the switching abilities between J-type aggregated and non-aggregated states of a cationic cyanine dye, 1,1′-diethyl-2,2′-cyanine (pseudoisocyanine, PIC) intercalated in the interlayer space of synthetic saponite (Sap) were compared. The switching was performed by adding and removing of dimethyl sulfoxide (DMSO) from the interlayer space. The PIC/Sap hybrid film prepared at 70% CEC loading level has shown excellent stability within 20 cycles of photophysical response after adding and removing of DMSO from the interlayer space, indicating that presented experimental approach can be useful in the future development of artificial light harvesting or semiconductor systems with controllable properties.

Creators : Marian Matejdes | Himeno Daisuke | Suzuki Yasutaka | Kawamata Jun Publishers : Elsevier B.V. All Date Issued : 2017-05

Clay–organic hybrid films exhibiting reversible fluorescent color switching induced by swelling and drying of a clay mineral

The Journal of Physical Chemistry C Volume 120 Issue 41

The interlayer space of clays is an interesting microenvironment to control the properties of included organic materials. In this study, chromic hybrid films consisting of synthetic saponite (SSA) and fluorescent organic molecules with planar p-conjugated systems were fabricated. The hybrid films exhibited reversible fluorescence color switching induced by swelling and drying, which caused the gallery height of SSA to change. Ultraviolet–visible absorption, steady-state and time-resolved fluorescence measurements of the hybrid films strongly suggested that the organic molecules formed an excimer in the swollen interlayer space of SSA, while they were a monomer in the dried interlayer space. The different emission wavelengths of the excimer and monomer resulted in the fluorescence color switching of the hybrid films. The reversibility of the color switching was maintained for at least 50 cycles with no change of fluorescence maxima. These chromic hybrid films represent a novel approach to obtain color switching.

Directionally tunable and mechanically deformable ferroelectric crystals from rotating polar globular ionic molecules

Nature chemistry Volume 8 Issue 10

Ferroelectrics have found a wide range of applications including memory elements, capacitors, and sensors. Molecular f erroelectric crystals have recently attracted growing interest as viable alternatives for conventional ceramic ferroelectrics, especially due to their non toxicity and solution processability. Herein, we show that a class of molecular compounds known as plastic crystals can exhibit ferroelectricity, provided that the constituent molecules are judiciously chosen from polar ionic molecules. The intrinsic features of plastic crystals, e.g. the rotational mot ion of molecules and phase transitions with lattice symmetry changes, provide the crystals with unique ferroelectric properties relative to conventional molecular crystals , i.e. the possibility to flexibly alter the direction of the polarization axis of a grown crystal by applying an electric field. Owing to t he tunability of the crystal orientation together with mechanical deformability, this novel type of molecular crystals represents an attractive functional material, which will undoubtedly find diverse applications.

Biological oxygen sensing via two-photon absorption by an ir(III) complex using a femtosecond fiber laser

Japanese Journal of Applied Physics Volume 55 Issue 9

Near-infrared two-photon absorption of the phosphorescent Ir(III) complex (2,4-pentanedionato-κO2,κO4)bis[2-(6-phenanthridinyl-κN)benzo[b]thien-3-yl-κC]iridium (BTPHSA) was characterized. It exhibited a 800–1200 nm two-photon absorption band, and thus could be electronically excited by 1030-nm femtosecond Ti:sapphire and Yb-doped fiber lasers. By using BTPHSA, oxygen concentrations in human embryonic kidney 293 (HEK293) cells were imaged. These results demonstrate two-photon oxygen sensing of live tissues via easily operable excitation sources.

Three-photon induced luminescence of europium acetylacetonate type complexes

Chemistry Letters Volume 45 Issue 5

We measured the three-photon absorption spectra of two europium acetylacetonate-type complexes. The three-photon absorption peak wavelengths of tris(hexafluoroacetylacetonato)europium(III) (Eu(hfa)) and tris(2-naphthoyltrifluoroacetonato)europium(III) (Eu(ntfa)) were 925 and 1025 nm, respectively. The peak values of the 3PA cross-sections of Eu(hfa) and Eu(ntfa) were 1.9 and 13.9 GM (1 GM = 10−82 cm6 s2), respectively. Using Eu(ntfa) as a probe, a three-photon microscope image of a living cell was obtained using a 1030 nm operating femto-second fiber laser as the light-source. Thus, Eu(ntfa) is a fiber laser excitable luminescent probe useful for three-photon microscopy.

Narrowing of X-ray diffraction peak of clay-organic hybrid films by swelling and drying procedure

Clay Science Volume 19 Issue 4

We have found that X-ray diffraction peaks of clay-organic hybrid films were narrowed after swelling followed by removing of solvent. We fabricated hybrid films consisting of natural montmorillonite (Mont), synthetic saponite (SSA) or synthetic stevensite (SST) and a cationic organic molecule. Full width at half maximum (FWHM) of 001 reflection of as-prepared Mont hybrid was 1.58 2θ degree whereas that after swelling and solvent removing procedure was 0.84 2θ degree. This decreasing of FWHM indicated that the improvement of packing order of clay particles in clay-organic hybrid was occurred during swelling and solvent removing procedure. Similar decreasing of FWHM was also found in hybrids consisting of SSA or SST. Improvement of packing order of hybrid was found to accompany suppression of light scattering of hybrid at the same time.

歴史のなかの聖地と記憶のなかの〈聖地〉 : 福建客家社会における寧化石壁、李氏大宗祠、保生大帝廟

Creators : Kobayashi Hiroshi Publishers : 風響社 Date Issued : 2019-03-20

僑郷からの災因論 : 二一世紀における「古典的」な風水事例より

Creators : Kobayashi Hiroshi Publishers : Kohro-sha Date Issued : 2016-03-20

Future issues in Yamaguchi University student counseling center

山口大学学生相談所年報 Volume 28-29

Creators : Tanabe Toshiaki Publishers : 山口大学学生支援センター Date Issued : 2019-01-31

発達障害の特性がみられる学生への支援についての一考察 : 看護学を専攻する学生が抱える困難を通して

山口大学学生相談所年報 Volume 28-29

Creators : 廣中香子 Publishers : 山口大学学生支援センター Date Issued : 2019-01-31

セクシュアル・マイノリティ支援と学生相談

山口大学学生相談所年報 Volume 28-29