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81.
A new optical CO2 sensor based on the luminescence intensity change of the europium(III) complex tris(thenoyltrifluoroacetonato) europium(III) dihydrate ([Eu(tta)3]) caused by the absorption change of various pH indicators—thymol blue, phenol red, or cresol red—with CO2 was developed and its CO2 sensing properties were investigated. For all the CO2 sensors using pH indicators the observed luminescence intensity from [Eu(tta)3] at 613 nm increased with increasing CO2 concentration. The linear calibration method based on the plot of (I100–I0)/(I–I0) versus the inverse of CO2 concentration was suggested, where I0 and I100 were luminescence intensities at 613 nm of the CO2 sensor film in 100% nitrogen and 100% gaseous CO2. In all cases the plots showed good linearity and the correlation factors of the plots, r2, were 0.991 for thymol blue, 0.990 for phenol red, and 0.998 for cresol red. The slopes of the plots (A/B) for thymol blue, phenol red, and cresol red were 2.2, 5.2, and 9.0%, respectively. The response times of the CO2 sensor film were 4.0 s for thymol blue, 4.4 s for phenol red, and 8.8 s for cresol red for switching from nitrogen to CO2, and the recovery times of films were 36 s for thymol blue, 39.2 s for phenol red, and 56.6 s for cresol red for switching from CO2 to nitrogen. The signal changes were fully reversible and hysteresis was not observed during the measurements. The highly sensitive CO2 sensor was developed using thymol blue as an indicator for the CO2-sensing probe. 相似文献
82.
Shin-ichi Hirano Toshinobu Yogo Wataru Sakamoto Seiji Yamada Tomoyuki Nakamura Tomoe Yamammto Hiroyuki Ukai Kouichi Banno Tomoko Nakafuku Yukari Ando 《Journal of Sol-Gel Science and Technology》2003,26(1-3):35-41
Nano sized crystalline particles/polymer hybrids were synthesized form designed metal-organic precursors. The newly developed method is composed of the synthesis of organic matrix by polymerization and the in situ nucleation and growth of crystalline oxide particles in the organic matrix below 100°C. The design of metal-organic precursor modified with polymerizable ligand and the selection of reaction conditions does influence the size and crystallinity of ceramic particles in organic matrix. The nano-sized magnetic particle/polymer hybrid exhibits the interesting feature of superparamagnetism and quantum size effect. The crystalline particles of BaTiO3/, PbTiO3/, and KNbO3/polymer hybrids behave to be dielectric and show the typical electro-rheological behavior. 相似文献
83.
Tamura O Shiro T Ogasawara M Toyao A Ishibashi H 《The Journal of organic chemistry》2005,70(12):4569-4577
The 4-hydroxy 4-substituted glutamic acid moiety is a common substructure of biologically important natural products such as monatin [(2S,4S)-2], lycoperdic acid (3), and dysiherbaine (4). To develop methodology for syntheses of these natural products, cycloadditions of nitrone 5 with 2-substituted 2-propen-1-ols 6 and 2-substituted acrylates 8 were investigated. Reactions of nitrone 5 with alcohols 6 in the presence of MgBr2OEt2 gave cycloadducts 7 in a highly stereoselective manner, whereas noncatalyzed reactions of 5 with acrylates 8 afforded adducts 9. Using the former reaction, syntheses of monatin [(2S,4S)-2], monatin derivative 18, and lycoperdic acid (3) were accomplished. The C4-epimer of monatin [(2S,4R)-2)] was also synthesized by employing the latter cycloaddition. 相似文献
84.
M Yamaguchi T Yoshitake J Ishida M Nakamura 《Chemical & pharmaceutical bulletin》1989,37(11):3022-3025
A simple and sensitive high-performance liquid chromatographic method with fluorescence detection for the determination of nineteen 21-hydroxycorticosteroids is described. The corticosteroids are oxidized by cupric acetate to form the corresponding glyoxal derivatives. The derivatives are converted into fluorescent quinoxalines by reaction with 1,2-diamino-4,5-methylenedioxybenzene, a fluorogenic reagent for alpha-dicarbonyl compounds. The quinoxalines are separated within 70 min on a reversed-phase column (TSK gel ODS-120T) by stepwise elution with mixtures of methanol, acetonitrile, and 1.0 M ammonium acetate. The detection limits are 0.14-29.4 pmol at a signal-to-noise ratio of 3 in a 50-microliter injection volume. This sensitivity permits precise determination of hydrocortisone, cortisone, corticosterone, and their tetrahydro derivatives in 500 microliters of normal human urine. 相似文献
85.
Commercially available powdered photocatalysts such as P-25 are known to show high photocatalytic performance. However, in practical use, their anchoring onto a substrate without any binders is still very difficult. The purpose of this study is to design and develop high-performance photocatalysts that can be anchored onto a substrate, and to this end we have prepared a titanium oxide photocatalyst using a wet process. The results of this study led to the successful development of rectangular column structured titanium oxide crystals which could be anchored onto silica sheets. The rectangular columnar crystal was 100- 500 nm wide and 1000- 5000 nm long. Moreover, investigations on the complete oxidation reaction of acetaldehyde into CO2 and H2O showed a high performance equivalent to that of the most efficient marketed powdered photocatalysts. 相似文献
86.
Yagi Kiyohito Hamada Kenji Hlrata Kazumasa Miyamoto Kazuihisa Miura Yoshiharu Akano Tohru Fukatu Kiyomi Ikuta Yoshiaki Nakamura Hiroshi K. 《Applied biochemistry and biotechnology》1994,(1):225-232
A marine green alga,Chlamydomonas sp. strain MGA161 was cultivated under illumination of red and white lights. The growth rate under red light illumination
was almost the same as that in the basic conditions under white light illumination, but red light-grown cells accumulated
almost twice as much starch as white light-grown cells. Although there was a slight decrease in carbonic anhydrase activity,
red light-illuminated cells had almost 2.3 times the fructose-l,6-diphos-phatase activity of white light-illuminated cells.
Red light might stimulate starch accumulation by increasing the amounts of enzymes related to carbon fixation through the
phytochrome system. Cells grown under red light degraded 1.6 times as much starch and produced 1.7 times as much hydrogen
and 1.6 times as much ethanol compared with cells grown under white light during 12 h of dark anaerobic fermentation. 相似文献
87.
[reaction: see text]. An In(OTf)(3)-catalyzed addition of a beta-ketoester to acetylene in the presence of molecular sieves produces a alpha-vinylated ketoester in good to excellent yield. The vinylation reaction proceeds without any loss of elements in starting molecules under solvent-free conditions and allows the use of welding-grade acetylene, providing a practical method for synthetic utilization of acetylene gas. 相似文献
88.
[reaction: see text] Substituted cyclopentadienone acetals (CPDAs) were synthesized by a thermal or palladium-catalyzed [3 + 2] cycloaddition reaction of a substituted cyclopropenone acetal to an electron-deficient acetylene. The synthesis afforded di-, tri-, and tetra-substituted CPDAs of considerable structural varieties that undergo Diels-Alder reaction to produce bicyclo[2.2.1]heptenes. 相似文献
89.
Yoshida H. Yang M. Masaka K. Houshito Y. Mashiko K. Nakamura S. 《Journal of Thermal Analysis and Calorimetry》2002,70(3):703-711
Phase transition behavior of polyesters derived from 2,7-phenanthrene dicarbonic acid diethylester and alkanediols with even
methylene carbon number was investigated by the simultaneous DSC-XRD method. The smectic A phase was observed on cooling from
the molten state. The transition entropy from the isotropic state to the smectic A phase was about 9.0 J mol-1 K-1, which depended on the methylene carbon number. The linear expansion coefficients, based on the (001) spacing of the crystalline
phase at room temperature, were 1.3·10-4 K-1 (crystalline phase), 5.7·10-4 K-1 (crystallization region), 1.7·10-3 K-1 (smectic A phase) during cooling, and 1.5·10-4 K-1 (crystalline phase), and 1.0·10-3K-1(melting region) on heating.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
90.
Yasuo Saegusa Sakayu Iida Shigeo Nakamura Nguyen Chau Yoshio Iwakura 《Journal of polymer science. Part A, Polymer chemistry》1984,22(5):1017-1023
Aromatic polythioamide-oxothioxoquinazolines were synthesized by the polycondensation of 2,2′-(m-phenylene)bis-1,3,4-thiadiazoline-5-thione with aromatic bis-o-amino esters. The polymerizations were carried out at 160°C in acidic media such as m-cresol, sulfolane, and polyphosphoric acid to produce polymers with reduced viscosities up to 0.5 dL/g. These polymers were soluble in polar aprotic solvents like N-methyl-2-pyrrolidone and some acidic media including m-cresol. The polythioamide-oxothioxoquinazolines showed relatively good thermal stability with 10% weight loss at 344–394°C in air. 相似文献