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1.
We studied the simultaneous quantitative analysis of biologically active substances, such as nicotinic acid, trigonelline, caffeine, qunolinic acid and tannic acid and pyrogallic acid, in several roasted coffees by an HPLC/diode-array system with a home-made sol-gel and ODS-2 columns. A simple method for simultaneous quantitative analysis of biologically active substances in the coffee brew became feasible by an HPLC/diode-array system with a sol-gel column at a single wavelength of 210 nm. The most efficient condition of the Rs value was above 1.05 when two sol-gel columns were connected. In addition, the elution behavior of nicotinic acid in brew extracted from commercially available coffee beans suggests the thermal decomposition process during roasting, and indicated the maximum value for full city roasted coffee. 相似文献
2.
Megumi Ban Michihisa Kyoto Akira Uedono Takao Kawano Shoichiro Tanigawa 《Journal of Polymer Science.Polymer Physics》1996,34(7):1189-1195
Free volume characteristics in three samples of monodisperse polystyrene were investigated by positron annihilation technique over a temperature range from 300 to 380 K. The number-average molecular weight of the samples ranged from 5730 to 1,524,000. The observed lifetime spectra were resolved into three components, where the longest lifetime, τ3 was associated with the pick-off annihilation of ortho-positronium (o-Ps) trapped by free volumes. The change of the temperature coefficient of τ3 was observed at around 350 K, at which the value of τ3 was a constant value of 2,3 ns for all specimens with different molecular weights. There was no discrete change of τ3 in intensity, which is corresponding to the number of free volumes. The size of free volume at glass transition was evaluated to be 0.l nm3. © 1996 John Wiley & Sons, Inc. 相似文献
3.
Hiroshi Onoue Masayuki Narisada Shoichiro Uyeo Hiromu Matsumura Kyo Okada Toshisada Yano Wataru Nagata 《Tetrahedron letters》1979,20(40):3867-3870
Allylazetidinones , , prepared by coupling of allylcoppers with chloroazetidinones , , were converted into carbapenem esters , – using an Emmons-Horner reaction to introduce the 6-side chain and an intramolecular Wittig reaction to form the carbapenem ring system. 相似文献
4.
Preparation and mechanical properties of bacterial cellulose nanocomposites loaded with silica nanoparticles 总被引:3,自引:0,他引:3
Shoichiro Yano Hideaki Maeda Megumi Nakajima Toshiki Hagiwara Takashi Sawaguchi 《Cellulose (London, England)》2008,15(1):111-120
Bacterial cellulose (BC), which is produced by Gluconacetobacter xylinus (Ga. xylinus) in culture, is made up of a three-dimensional network of ribbon-shaped bundles of cellulose microfibrils. In the current
studies, we used two processes to prepare nanocomposites of BC filled with silica particles. In Process I, Ga. xylinus was incubated in medium containing silica sol Snowtex 0 (ST 0, pH 2–4) or Snowtex 20 (ST 20, pH 9.5–10.0). The elastic modulus
at 20 °C was improved by keeping the amount of silica in the nanocomposites below 4% when ST 20 was used and below 8.7% when
ST 0 was used. This process allowed incorporation of 50% silica in BC. Inclusion of higher amounts of silica reduced the modulus
at 20 °C and the strength of the nanocomposites below that of BC. X-ray diffraction measurements revealed that the silica
particles disturb the formation of ribbon-shaped fibrils and affect the preferential orientation of the (
) plane. We also produced BC-silica nanocomposites by Process II, wherein the BC hydrogel was immersed in different concentrations
of silica sols, allowing silica particles to diffuse into the BC hydrogel and lodge in the spaces between the ribbon-shaped
fibrils. This method increased the modulus at 20°C and the strength compared to the BC matrix, but it was difficult to load
the BC with more than 10% silica in this way. 相似文献
5.
This paper is concerned with melting of a vertical ice layer adhering to the substrate by using radiating heat source of halogen lamps having a large fraction of short wave beam or nichrome heater having a comparatively large fraction of long wave one. From the present experimental results, it can be seen that the heating of short wave radiation produces a peculiar melting behavior of strongly rough melting-surface due to the internal melting at the grain boundary of ice-surface. On the other hand, for the case of long wave radiation the melting-surface becomes very smooth. The melting rate of clear ice layer by short wave radiation obtained from halogen lamps is smaller than that of cloudy ice layer due to the good penetration of short wave fraction through the clear ice layer. Moreover, the raising of temperature of ice-substrate interface could offer a feasibility of removing ice layer from the structure subject to atmospheric icing. Concludingly, it is clarified that the melting rate of ice layer could be predicted numerically by using the band model of extinction coefficient or absorption coefficient presented in this study.
Nomenclature A transmission, defined in equation (4) - a monochromatic absorption coefficient of clear ice - C constant - Eb monochromatic emissive power - hi thickness of ice layer - hin initial thickness of ice layer - hm thickness of substrate - k0 extinction coefficient for h0 0 - ks modified extinction coefficient - k monochromatic extinction coefficient - Li latent heat of melting - n index number, defined in equation (2) - heat flux absorbed at surface of substrate - qr0 radiant heat flux impinged onto ices-urface - qri{y} radiant heat flux in ice layer - S distance from initial ice-surface to transient melting-surface - Tb temperature of radiating heat source - Ti temperature in ice layer - Tm temperature in substrate - T environmental temperature - T1 temperature of surface of ice layer - T2 temperature of substrate-surface - T3 temperature of back side surface of substrate - t time - y distance from initial ice-surface - Z ratio of backward radiative heat flux to forward one for cloudy ice Greek Symbols heat transfer coefficient - i thermal diffusivity of ice - m thermal diffusivity of substrate - i thermal conductivity of ice - m thermal conductivity of substrate - wavelength - c critical wavelength - i density of ice - Stefan-Boltzmann constant 相似文献
Schmelzen einer Eisschicht an einer senkrechten Wand durch Strahlung
Zusammenfassung Diese Arbeit behandelt das Schmelzen einer senkrechten Eisschicht auf einer Unterlage mit Hilfe von Halogen-Lampen mit einem hohen Anteil an kurzen Wellen und Nichromheizern mit einem hohen Anteil an langen Wellen. Aus diesen Versuchen läßt sich ableiten, daß die Heizung durch kurzwellige Strahlung ein eigentümliches Schmelzverhalten mit sehr rauher Oberfläche hervorruft, verursacht durch Schmelzen an den Korngrenzen der Eisoberfläche. Bei langwelliger Heizung wird die Oberfläche sehr glatt. Die Abschmelzrate einer Klareisschicht bei kurzwelliger Heizung durch Halogen-Lampen ist geringer als die einer Opaleisschicht wegen des besseren Eindringens der kurzen Wellen in das klare Eis. Der Temperaturanstieg an der Grenze Eis — Unterlage bietet die Möglichkeit der Enteisung von Bauteilen, die der atmosphärischen Vereisung ausgesetzt sind. Es folgt, daß die Abschmelzrate einer Eisschicht, numerisch vorausberechnet werden kann, indem man das Bandmodell des Extinktions- und des Absorptionskoeffizienten dieser Arbeit verwendet.
Nomenclature A transmission, defined in equation (4) - a monochromatic absorption coefficient of clear ice - C constant - Eb monochromatic emissive power - hi thickness of ice layer - hin initial thickness of ice layer - hm thickness of substrate - k0 extinction coefficient for h0 0 - ks modified extinction coefficient - k monochromatic extinction coefficient - Li latent heat of melting - n index number, defined in equation (2) - heat flux absorbed at surface of substrate - qr0 radiant heat flux impinged onto ices-urface - qri{y} radiant heat flux in ice layer - S distance from initial ice-surface to transient melting-surface - Tb temperature of radiating heat source - Ti temperature in ice layer - Tm temperature in substrate - T environmental temperature - T1 temperature of surface of ice layer - T2 temperature of substrate-surface - T3 temperature of back side surface of substrate - t time - y distance from initial ice-surface - Z ratio of backward radiative heat flux to forward one for cloudy ice Greek Symbols heat transfer coefficient - i thermal diffusivity of ice - m thermal diffusivity of substrate - i thermal conductivity of ice - m thermal conductivity of substrate - wavelength - c critical wavelength - i density of ice - Stefan-Boltzmann constant 相似文献
6.
Hidekazu Miyaji Junko Fujimoto Riho Mabuchi Moeno Okumura Shoichiro Goto Youtaro Honda 《Tetrahedron letters》2017,58(37):3623-3627
A novel molecular sensor using anthracene bearing two amidopyridines emits blue fluorescence in the presence of succinic acid and green fluorescence in the presence of malonic acid, and its fluorescence intensity increased upon binding. Using this molecular sensor, we succeeded in detecting the difference of one carbon atom between succinic acid and malonic acid with the naked-eye. Furthermore, when methylmalonic acid was dissolved in urine to provide a model system for methylmalonic aciduria, the fluorescence changed from blue to green, and methylmalonic acid was successfully detected with the naked-eye. 相似文献
7.
An experimental study has been conducted to evaluate the influence of the presence of inner tube and the Rayleigh number on free convective heat transfer in an open thermosyphon. Water and fluorocarbon R-11 refrigerant as the working fluids were utilized. Heat transfer results using the concentric geometry were given for modified Rayleigh number from 3.6×102 to 4.1 × 107 which encompasses the regions of similarity, impeded and boundary layer flow conditions. It was found that the presence of the inner tube markedly increases the overall heat transfer coefficient of open thermosyphon by a factor as large as 2 to 10 in the turbulent impeded and boundary layer regimes.
Nomenclature a inner radius of heated tube, D/2 - Ain sectional space area of inner tube, d i 2 /4 - Aan sectional space area of annulus, (D2-d 0 2 )/4 - Cp specific heat - di inner diameter of inner tube - d0 outer diameter of inner tube - D inner diameter of heated tube - g gravitational acceleration - L tube length of thermosyphon - Nua Nusselt number based on inner radius of heated tube - Nur Nusselt number based on equivalent heattransfer radius - Nux Nusselt number, defined in equation (1) - Pr Prandtl number, defined in equation (3) - q heat flux from heated tube - r equivalent heat-transfer radius, defined in equation (4) - Raa modified Rayleigh number based on inner radius of heated tube - Rar modified Rayleigh number based on equivalent heat-transfer radius - Rax modified Rayleigh number, defined in equation (2) - Te temperature of entrance-fluid - Tw temperature of heated surface - T temperature difference between heated wall and entrance-fluid, Tw-Te Greek Symbols coefficient of volumetric expansion - thermal diffusivity - thermal conductivity - viscosity - kinematic viscosity 相似文献
Wärmeübergang in einem Thermosyphon aus konzentrischem Rohr bei einphasiger Strömung
Zusammenfassung Es wurde experimentell untersucht, wie der Einbau eines Innenrohres und wie die Rayleigh-Zahl auf die freie Konvektion in einem offenen Thermosyphon, gefüllt mit Wasser oder dem Kältemittel R 11, einwirkt. Der untersuchte Bereich bei konzentrischer Geometrie lag bei modifizierten Rayleigh-Zahlen von 3,6 · 102 bis 4,1 · 107 und umfaßte damit die Regionen der Grenzschichtströmung. Es ergab sich, daß der Einbau eines Innenrohres den Gesamtwärmeübergang eines offenen Thermosyphons im Bereich der behinderten turbulenten Strömungen und Grenzschichtströmungen um den Faktor 2 bis 10 steigert.
Nomenclature a inner radius of heated tube, D/2 - Ain sectional space area of inner tube, d i 2 /4 - Aan sectional space area of annulus, (D2-d 0 2 )/4 - Cp specific heat - di inner diameter of inner tube - d0 outer diameter of inner tube - D inner diameter of heated tube - g gravitational acceleration - L tube length of thermosyphon - Nua Nusselt number based on inner radius of heated tube - Nur Nusselt number based on equivalent heattransfer radius - Nux Nusselt number, defined in equation (1) - Pr Prandtl number, defined in equation (3) - q heat flux from heated tube - r equivalent heat-transfer radius, defined in equation (4) - Raa modified Rayleigh number based on inner radius of heated tube - Rar modified Rayleigh number based on equivalent heat-transfer radius - Rax modified Rayleigh number, defined in equation (2) - Te temperature of entrance-fluid - Tw temperature of heated surface - T temperature difference between heated wall and entrance-fluid, Tw-Te Greek Symbols coefficient of volumetric expansion - thermal diffusivity - thermal conductivity - viscosity - kinematic viscosity 相似文献
8.
Professor S. Fukusako S. Ishiguro Professor Emeritus N. Seki 《Heat and Mass Transfer》1988,22(1-2):13-22
Experiments were performed to study the effect of air fluidization velocity, particle diameter, tube diameter, and pitch between tubes on heat-transfer coefficient for a bundle of horizontal tubes immersed in an aggregative fluidized bed. Not only horizontal but also vertical distributions of the heat-transfer coefficients within the bundle were also extensively determined. The heat-transfer coefficient and its maximum value were found to be dependent on the particle diameter, the air fluidization velocity, and the gap between the tubes in the bundle. The proposed correlation for the maximum heat-transfer coefficient was in good agreement with the present results. 相似文献
9.
In this paper the horizontal layer of clear ice sticking to the substrate is melted by comparatively short wave radiation similar to solar radiation for the purpose of removing ice from the surface of the material subject to atmospheric icing. The radiating source used for melting is 300 wattages halogen lamps whose color temperature is 3200K at 100 voltages. From the present investigation, a typical phenomenon of backmelting is observed clearly and it can be found that the predicted results including the melting rate of upper and lower layers which are melted by radiant energy impinged on or penetrated the ice layer are in good agreement with the experimental results.
Nomenclature av monochromatic absorption coefficient - A transmission (= q r + {hi}/qro) - cp specific heat - Ebv monochromatic emissive power - hD mass transfer coefficient - hi initial thickness of ice layer - hm thickness of substrate - Li latent heat of melting - Lw latent heat of evaporation or condensation - heat flux absorbed at surface of substrate - qr0 radiant heat flux impinged onto ice or free surface - q r + {y} forward radiant heat flux - q r – {y} backward radiant heat flux - S1 thickness of upper melt layer - S2 thickness of lower melt layer - S'2 distance from free surface to bottom surface of ice layer - t time - T temperature - T1 temperature of air-water or air-ice interface - T2 temperature of substrate surface - T3 temperature of back side surface of substrate - Tb temperature of radiating source - Ti temperature in ice layer - Tw1 temperature in upper melt layer - Tw2 temperature in lower melt layer - T environmental temperature - Ww saturated vapor concentration at free surface - Wt8 vapor concentration at environment - y distance from free or ice surface - y grid size of water or ice - ym grid size of substrate Greek symbols heat transfer coefficient - spectral absorptivity - t total absorptivity - i thermal diffusivity of ice - m thermal diffusivity of substrate - w thermal diffusivity of water - i thermal conductivity of ice - m thermal conductivity of substrate - w thermal conductivity of water - wavelength - av densitiy of air-vapor mixture - i density of ice - Stefan-Boltzman constant 相似文献
Aufschmelzen einer waagerechten Klareisschicht durch Strahlung
Zusammenfassung Eine waagerechte Klareisschicht, die auf einer Unterlage aufgefroren war, wurde durch kurzwellige Strahlung, Ähnlich der Sonnenstrahlung, zum Schmelzen gebracht, um die Entfernung von Eis nach atmosphÄrischer Vereisung zu untersuchen. Die Strahlungsquelle war eine 300 Watt-Halogenlampe mit einer Farbtemperatur von 3200 Kelvin bei 100 Volt. Als typische Erscheinung wurde ein Rückseiten-Schmelzen gefunden, im übrigen sind die vorausberechneten Schmelzraten an der Ober- und der Unterseite durch aufgenommene oder durchgelassene Strahlungsenergie in guter übereinstimmung mit den Messungen.
Nomenclature av monochromatic absorption coefficient - A transmission (= q r + {hi}/qro) - cp specific heat - Ebv monochromatic emissive power - hD mass transfer coefficient - hi initial thickness of ice layer - hm thickness of substrate - Li latent heat of melting - Lw latent heat of evaporation or condensation - heat flux absorbed at surface of substrate - qr0 radiant heat flux impinged onto ice or free surface - q r + {y} forward radiant heat flux - q r – {y} backward radiant heat flux - S1 thickness of upper melt layer - S2 thickness of lower melt layer - S'2 distance from free surface to bottom surface of ice layer - t time - T temperature - T1 temperature of air-water or air-ice interface - T2 temperature of substrate surface - T3 temperature of back side surface of substrate - Tb temperature of radiating source - Ti temperature in ice layer - Tw1 temperature in upper melt layer - Tw2 temperature in lower melt layer - T environmental temperature - Ww saturated vapor concentration at free surface - Wt8 vapor concentration at environment - y distance from free or ice surface - y grid size of water or ice - ym grid size of substrate Greek symbols heat transfer coefficient - spectral absorptivity - t total absorptivity - i thermal diffusivity of ice - m thermal diffusivity of substrate - w thermal diffusivity of water - i thermal conductivity of ice - m thermal conductivity of substrate - w thermal conductivity of water - wavelength - av densitiy of air-vapor mixture - i density of ice - Stefan-Boltzman constant 相似文献
10.
Saipin Thanachasai Shunsaku Rokutanzono Shoichiro Yoshida Tadashi Watanabe 《Analytical sciences》2002,18(7):773-777
Amperometric hydrogen peroxide biosensors were fabricated by incorporating horseradish peroxidase (HRP) into poly[pyrrole-co-[4-(3-pyrrolyl)butanesulfonate]] (Py-PS) copolymer films deposited on an SnO2 electrode surface by electropolymerization. The HRP/Py-PS electrodes exhibited an extended dynamic range and a markedly improved operational and storage stability, compared with HRP-incorporated polypyrrole (PPy) electrodes prepared under similar conditions. The linear range was expanded from 10(-7)-10(-4) M to 10(-7)-10(-3) M H2O2. In about 80 measurements over three weeks, the HRP/Py-PS electrode retained 60% of its initial response, while the HRP/PPy electrode almost completely lost activity. The influence of the electrodeposition solution pH on the sensor response was also investigated. Our results suggest that an expansion of the linear range and an enhancement of lifetime are due to electrostatic interactions of HRP with a negatively-charged Py-PS copolymer. 相似文献