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11.
Toru Ikegami Hideyuki Negishi Dai Kitamoto Keiji Sakaki Tomohiro Imura Masayoshi Okamoto Yasushi Idemoto Nobuyuki Koura Tsuneji Sano Kenji Haraya Hiroshi Yanagishita 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2005,80(4):381-387
In order to produce highly concentrated bioethanol by pervaporation using an ethanol‐permselective silicalite membrane, techniques to suppress adsorption of succinic acid, which is a chief by‐product of ethanol fermentation and causes the deterioration in pervaporation performance, onto the silicalite crystals was investigated. The amount adsorbed increased as the pH of the aqueous succinic acid solution decreased. The pervaporation performance also decreased with decreasing pH when the ternary mixtures of ethanol/water/succinic acid were separated. Using silicalite membranes individually coated with two types of silicone rubber, pervaporation performance was significantly improved in the pH range of 5 to 7, when compared with that of non‐coated silicalite membranes in ternary mixtures of ethanol/water/succinic acid. Moreover, when using a silicalite membrane double‐coated with the two types of silicone rubber, pervaporation performance was stabilized at lower pH values. In the separation of bioethanol by pervaporation using the double‐coated silicalite membrane, removal of accumulated substances having an ultraviolet absorption maximum at approximately 260 nm from the fermentation broth proved to be vital for efficient pervaporation. Copyright © 2005 Society of Chemical Industry 相似文献
12.
Hiroshi Ohta Tomoyuki Hirota Abdur Rahim 《The International Journal of Advanced Manufacturing Technology》2007,33(1-2):36-41
This paper analyzes a multi-product production / inventory system where demands for each item arrive according to a Poisson
process and the production time for each product has an Erlang distribution. The paper proposes an optimality condition that
specifies whether each product should be produced make-to-stock or make-to-order. In the event a product should be produced
make-to-stock, an approach for computing the optimal base-stock level is proposed. Numerical examples are given for illustrative
purpose. 相似文献
13.
Two deacetyl-thymosin β4 analogues containing Phe(4Br) or D-Phe(4Br) as position 12 were synthesized by the manual solid-phase method, and their immunological effects on the impaired blastogenic response of phytohemagglutinin-stimulated T lymphocytes of uremic patients with infectious diseases were studied. Bromination of the p-position of Phe12 resulted in a marked restorative effect on the impaired blastogenic response of T lympocytes compared with that of our synthetic deacetyl-thymosin β4 The synthetic [Phe(4Br)12]deacetyl-thymsin β4 was approximately equal in potency to our synthetic [Phe(4F)12]deacetyl-thymosin β4 in uremic patients, but the other analogue, [D-Phe(4Br)12]deacetyl-thymosin β4, had no effect. 相似文献
14.
The oxidation of Fe(II) with dissolved molecular oxygen was studied in sulfuric acid solutions containing 0.2 mol . dm-3 FeSO4 at temperatures ranging from 343 to 363 K. In solutions of sulfuric acid above 0.4 mol . dm-3, the oxidation of Fe (II) was found to proceed through two parallel paths. In one path the reaction rate was proportional
to both [Fe2+]2 and po2, exhibiting an activation energy of 51.6 . kJ mol-1. In another path the reaction rate was proportional to [Fe2+]2, [SO4-], and po2 with an activation energy of 144.6 kJ . mol-1. A reaction mechanism in which the SO4- ions play an important role was proposed for the oxidation of Fe(II). In dilute solutions of sulfuric acid below 0.4 mol
. dm-3, the rate of the oxidation reaction was found to be proportional to both [Fe(II)]2 and Po2, and was also affected by [H+] and [SO2-
4]. The decrease in [H+] resulted in the increase of reaction rate. The discussion was further extended to the effect of Fe (III) on the oxidation
reaction of Fe (II). 相似文献
15.
A new type of arc plasma reactor with 12-phase alternating current (AC) discharge for synthesis of carbon nanotubes (CNTs) is proposed. A couple of six discharge electrodes by which have mutually electrical connection between them to enlarge the high-temperature regions in the reactor are arranged to three-dimensional locations. A new method of CNTs fabrication by this reactor, which accomplishes to enlarge the suitable growth region in high purity and at high yield, was developed. 相似文献
16.
17.
A molecular orbital approach to materials design has recently made great progress. This approach is based on the electronic structure calculations by the DV-Xα cluster method. In this paper recent progress in this approachis reviewed. In particular 相似文献
18.
Highly transparent cellulose hydrogels with physical crosslinkage were prepared from nonaqueous organic cellulose solutions and viscose by coagulating and regenerating cellulose in an aqueous solution containing a water‐miscible organic solvent. Nonaqueous organic cellulose solutions used were LiCl/dimethylacetamide, paraformaldehyde/dimethyl sulfoxide, and triethylammonium chloride/dimethyl sulfoxide. Preparation conditions and physical properties of the transparent cellulose hydrogels were studied. The transparency of the cellulose hydrogels depended on the composition of the aqueous solution containing the organic solvent. Furthermore, transparent cellulose hydrogels from viscose showed high tensile strength. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3020–3025, 2003 相似文献
19.
Kyoko Kawagishi Hiroshi Harada Akihiro Sato Atsushi Sato Toshiharu Kobayashi 《JOM Journal of the Minerals, Metals and Materials Society》2006,58(1):43-46
The fourth-generation nickel-based single-crystal superalloys, which contain large amounts of refractory metals for strengthening
and platinum group metals for topologically close-packed phase prevention, show excellent high-temperature strength. However,
these alloying elements seem to decrease high-temperature oxidation resistance. In this study, nickel-based superalloys with
various amounts of tantalum, rhenium, and ruthenium were examined in isothermal and cyclic exposures at 1,100°C to investigate
the effect on the oxide growth rate and resistance to scale spallation. Ruthenium and rhenium were found to degrade the oxidation
resistance by the vaporization of their oxide. Tantalum-rich oxide in the spinel layer acts to stabilize ruthenium and rhenium
oxide in the scale. The addition of hafnium and yttrium is effective in improving the oxidation resistance of ruthenium-containing
nickel-based superalloys. 相似文献
20.
Yoshio Yamashita Hideyuki Jinbo Ryuji Kawazu Takateru Asano Hiroshi Umehara 《Polymer Engineering and Science》1991,31(12):855-859
LMR-UV (“low molecular weight resist for uv lithography”), a naphthoquinone-diazide sulfonic acid ester of a novolak resin, is a negative working resist. The mechanism of insolubilization of LMR-UV is based on the facts that the naphthoquinone-diazide moiety is decomposed to indenecarboxylic acid (polar compound) by photolysis upon UV irradiation and that the irradiated resist film insolubilizes in a non-polar developer. LMR-UV reliably forms 0.6 μm lines and spaces over a reflective substrate with steps by using a g-line stepper having a 0.35 NA lens. 0.6 μm-wide aluminum patterns over topography are obtained by use of g-line exposure and reactive ion etching. By use of an i-line aligner (NA = 0.42), LMR-UV resolves 0.25 μm space patterns with overhang profiles. The profiles are due to the large absorption coefficient of 3.8 μm?1. 0.3 μm wide aluminum patterns are formed by i-line exposure and lift-off metallization. 相似文献