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61.
Yumiko Ohtsuka Prof. Takahiro Seki Prof. Yukikazu Takeoka 《Angewandte Chemie (International ed. in English)》2015,54(51):15368-15373
We report the preparation of thermally tunable hydrogels displaying angle‐independent structural colors. The porous structures were formed with short‐range order using colloidal amorphous array templates and a small amount of carbon black (CB). The resultant porous hydrogels prepared using colloidal amorphous arrays without CB appeared white, whereas the hydrogels with CB revealed bright structural colors. The brightly colored hydrogels rapidly changed hues in a reversible manner, and the hues varied widely depending on the water temperature. Moreover, the structural colors were angle‐independent under diffusive lighting because of the isotropic nanostructure generated from the colloidal amorphous arrays. 相似文献
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We have developed a portable device for formaldehyde monitoring with both high sensitivity and high temporal resolution, and carried out indoor air formaldehyde concentration analysis. The absorbance difference of the sensor element was measured in the monitoring device at regular intervals of, for example, one hour or 30 min, and the result was converted into the formaldehyde concentration. This was possible because we found that the lutidine derivative that was formed as a yellow product of the reaction between 1-phenyl-1,3-butandione and formaldehyde was stable in porous glass for at least six months. We estimated the reaction rate and to be 0.049 min−1 and the reaction occurred quickly enough for us to monitor hourly changes in the formaldehyde concentration. The detection limit was 5 μg m−3 h. We achieved hourly formaldehyde monitoring using the developed device under several indoor conditions, and estimated the air exchange rate and formaldehyde adsorption rate, which we adopted as a new term in the mass balance equation for formaldehyde, in one office. 相似文献
66.
Usuki H Yamamoto Y Arima J Iwabuchi M Miyoshi S Nitoda T Hatanaka T 《Organic & biomolecular chemistry》2011,9(7):2327-2335
A new S9 family aminopeptidase derived from the actinobacterial thermophile Acidothermus cellulolyticus was cloned and engineered into a transaminopeptidase by site-directed mutagenesis of catalytic Ser(491) into Cys. The engineered biocatalyst, designated aminolysin-A, can catalyze the formation of peptide bonds to give linear homo-oligopeptides, hetero-dipeptides, and cyclic dipeptides using cost-effective substrates in a one-pot reaction. Aminolysin-A can recognize several C-terminal-modified amino acids, including the l- and d-forms, as acyl donors as well as free amines, including amino acids and puromycin aminonucleoside, as acyl acceptors. The absence of amino acid esters prevents the formation of peptides; therefore, the reaction mechanism involves aminolysis and not a reverse reaction of hydrolysis. The aminolysin system will be a beneficial tool for the preparation of structurally diverse peptide mimetics by a simple approach. 相似文献
67.
Pawlowska Z Lietard A Aloïse S Sliwa M Idrissi A Poizat O Buntinx G Delbaere S Perrier A Maurel F Jacques P Abe J 《Physical chemistry chemical physics : PCCP》2011,13(29):13185-13195
This work reports on the solvatochromic properties of a simple heterocyclic betaine pyridinium, 2-(1-pyridinio)benzimidazolate (SBPa), having promising potentialities in non-linear optics. From advanced PCM-TDDFT calculations, the solvatochromism of SBPa was found to be unusual, involving two different electronic states for absorption (S(0)→ S(2)) and emission (S(1)→S'(0)). To account for this behavior, we developed an innovative physical treatment which consists in a non-linear fit of the solvatochromic data using the Bilot-Kawski theoretical model and visualizing the least-square coefficient χ(2) on a 2D map as a function of the solute polarizability and gas phase absorption energy. In parallel, Kamlet-Taft correlations were undertaken to select a propitious set of electrostatic solvents usable in this treatment. Protic solvents that lead to specific interactions and nonpolar solvents that favor dimerization processes were excluded. From a choice of aprotic solvents with sufficiently high polarity, 4 dipole moments μ(g)(S(0)) = +9.1 D, μ(e)(S(2)) = -1.5 D, μ(e)(S(1)) = 0 D and μ(g)(S'(0)) = +3.31 D were determined, the 3 former values being in close agreement with TDDFT values, although the solute polarizability values seem underestimated. Anyhow, disregarding this discrepancy, we evaluated the static hyperpolarizability to β(0) = -64 × 10(-30) esu from the solvatochromic data in close agreement with DFT calculations. 相似文献
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This paper describes a new photoelastic technique for the spatiotemporal stress analysis. In a polarimeter developed, an elliptically
polarized signal beam of light, modulated in state of polarization by two-dimensional principal-stress distributions interferes
with a reference beam of light consisting of orthogonal linearly polarized two components. A time-sequential series of two-dimensional
interference patterns are received one after another by a MOS video camera, followed by a computer. Of the elliptically polarized
signal beam, the orthogonal field components along the directions of the principal stresses in a two-dimensional photoelastic
sample can be computed from a recorded interference pattern, which offer the data needer for mapping the spatiotemporal principal-stress
distribution over the sample. Not only each of the two orthogonal principal stresses but also the principal-stress difference
are mapped in a time-sequential diagram. No use of any movable polarization element such as a rotating analyzer allows us
to follow a rapid change in stress distribution within the maximum frame rate 2066 s−1 of the MOS video camera. 相似文献
69.
Satoshi Tanaka Kazuaki Yoshida Seiichiro Kinugasa Yoshihiro Ohtsuka 《Optical Review》1997,4(1):A92-A95
Novel birefringent single-mode fibers are fabricated with a vacant hole on either side of the central elliptical core, referred to as side-hole fiber, and their intrinsic and tension-induced modal birefringences are measured to know their characteristic properties for the purpose of making a strain sensor. Five sampled side-hole fibers are prepared for measurements. The sensitivity of the strain sensor is primarily determined by two parameters, tension-induced and intrinsic modal birefringences. Tension-induced modal birefringence is controllable by optimal arrangement of the size and location of the side-holes in the cross-section of the fiber. A sensitivity diagram for designating and fabricating side-hole fibers is presented. 相似文献
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