Search

Organic photovoltaic is one of the solar cell consists of fullerene derivative which is an n-type semiconductor and the conductive polymer as p-type semiconductor. In my research, silicon quantum dots was introduced to the active layer consisting of fullerene derivative (PCBM) and a conductive polymer (PCPDTBT), to prepare the hybrid photovoltaic. The prepared hybrid solar cell with Si quantum dots achieved better cell performance compared with controlled solar cell without quantum dots. The hybrid solar cell showed larger value of Incident photon-to-current conversion efficiencies and lower photoluminescence intensity. This indicated that domain size among phase separation in active layer was made smaller than the active layer of controlled solar cell, by introducing Si quantum dots. This change of aggregation structure by quantum dots was contributed to the improvement of cell characteristics.

The self-assembling properties of the 6-O- and 6′-O-alkylsucrose mixtures with different chain lengths including octyl, decyl, dodecyl, and tetradecyl under aqueous conditions were studied and compared with those of the 6-O- and 6′-O-hexadecylsucrose mixture previously reported. The title compounds were synthesized from sucrose in five steps. The results of scanning and transmission electron microscopes, powder X-ray diffraction, and dynamic light scattering measurements indicated that the self-assembling properties of octyl, decyl, and dodecyl derivatives were completely different from those of the 6-O- and 6′-O-hexadecylsucrose mixture. The three derivatives reported here primarily formed lamellar planes, which further induced the formation of vesicle-type particles under aqueous conditions, whereas the previous derivatives primarily formed spherical micelles in water, which further assembled according to face-centered cubic organization by a drying process from the aqueous dispersion. It was also found that the 6-O- and 6′-O-tetradecylsucrose mixture showed concentration-induced micelle-lamellar transition behavior in an aqueous dispersion. Furthermore, the mixing of a regioisomer, 6′-O-hexadecylsucrose, with 6-O-hexadecylsucrose induced different self-assembling properties from that of 6-O-hexadecylsucrose alone, but this effect did not appear in the self-assembling of the 6-O- and 6′-O-octylsucrose mixture.

A hole formed in photo-excited dye molecule under illumination is transferred to cathode with iodine ion in electrolyte solution in the dye-sensitized solar cell developed by M. Gratzel and the conductivity of the iodine ion affects conversion efficiency of the cell. In this work, effect of the polymeric p-type semiconductor on the hole transferability is investigated. PEDOT:PSS and P3HT were used as the p-type semiconductors. Dye-sensitized solar cells were composed of aluminium plate, Nb-doped TiO2 layer adsorbed with TCNQ, the electrolyte solution containing iodine ions, and ITO glass plate. In a solid-type cell substituted the electrolyte solution with the p-type semiconductor, photocurrent was not generated. The photocurrent was generated in the solar cell by introducing the electrolyte solution containing iodine ions between the ITO glass and the p-type semiconductor formed on the dye-adsorbed Nb-doped-TiO2 layer or between the dye-adsorbed Nb-doped-TiO2 layer and the p-type semiconductor formed on ...

To improve the light-to-electric energy conversion efficiency of a dye-sensitized solar cell, a p-type semiconductor electrode was introduced to the cell so that n/p tandem-type solar cell was comp...

This paper reports the synthesis and self-assembling properties of 6-O-hexadecyl- and 6-O-octylsucroses. Mono-etherification of 2,3,4,1′,3′,4′-hexa-O-benzylsucrose with the corresponding alkyl bromides predominantly took place at the glucose 6-position and the products were isolated by silica gel column chromatography. Benzyl groups in the isolated products were cleaved to yield the target derivatives. The SEM, TEM, XRD, and DLS results indicated that 6-O-alkylsucroses formed vesicle-type particles via formation of lamellar-like planes under aqueous conditions, which were further merged by fusion of the planes to construct larger aggregates. The self-assembling properties of the materials were different from those of the previously reported 6-O- and 6’-O-hexadecylsucroses mixture.

The thermal conductivity of MOX fuel containing FP precipitates such as oxide and metallic inclusions was evaluated by using a finite element method. (U0.8Pu0.2)O2 and (M0.94Nd0.06)O2 (M: U0.8Pu0.2) were employed as the fuel matrix, and BaUO3 and Mo-Ru-Rh-Pd alloy as the inclusions. The dispersed phase size and concentration were determined from post irradiation examination results of about 10 at.% burnup MOX fuel. 2.5 vol.% of the spherical inclusions with the diameter of 25 μm were dispersed in the fuel matrix cube with a size of 400×400×400 μm. The effect of the inclusions on the thermal conductivity of the fuel pellet was calculated to be at most several percents, which is about one order lower than that of the dissolved FPs.

The phase equilibria in the pseudo-ternary BaUO3-BaZrO3-BaMoO3 system were studied to understand the thermochemical properties of the perovskite type gray oxide phase in high burnup MOX fuel. Thermodynamic equilibrium calculation for the system was performed by using a ChemSage program under the various oxygen potentials. Solid solutions existing in the system were treated by an ideal solution model. The present calculation results well agreed with the previous reported post irradiation examination results, showing that BaMoO3 was scarcely included in the gray oxide phase.

Barium and Zr generated in nuclear fuels can precipitate as multi-component oxide with some other fission products. In addition, the solubility of Ba in the fuel depends on the oxygen potential and the temperature and Zr can easily dissolve into the fuel matrix. Therefore, the behavior of the Ba-Zr oxide inclusions during irradiation is rather complex. In this work, the composition of multi-component oxides and the distributions of Ba and Zr as a function of relative radius were evaluated with X-ray microanalysis. As results, the oxide inclusions containing both Ba and Zr and containing only Ba were observed in the fuel irradiated to the burnup of 13.3 and 10.6 at%, respectively. These results were discussed in terms of the solubility of Ba and Zr in the fuel and in terms of the rO2–UO2 phase diagram, together with the radial distributions of Ba and Zr in fuel matrix.

Three alpha-glucosidases which passed under the names of transglucosidase (from Aspergillus niger), maltase (from Brewers yeast), and isomaltase (from Bakers yeast) for reasons of their substrate specificities and transfer actions, were purified to electrophoretically pure states. These purified alpha-glucosidases were made uniform in the hydrolyzing activities using p-nitrophenyl alpha-glucopyranoside (alpha-p-NPG) and were reacted with p-nitrophenyl alpha-xylopyranoside (alpha-p-NPX) or isoprimeverose (xylopyranosyl-alpha-1,6-glucopyranose), which are typical substrates of alpha-xylosidase. Only Asp. niger alpha-glucosidase among them hydrolyzed alpha-p-NPX and isoprimeverose. Further the substrate specificities of three alpha-glucosidases and two alpha-xylosidases (I and II from Asp. flavus MO-5) were investigated on maltose, isomaltose, alpha-p-NPG, isoprimeverose, and alpha-p-NPX in detail, and kinetic parameters [Km, Vmax, and molecular activity (Ko)] were estimated and compared with each other. In the comparison of kinetic parameters, Asp. niger alpha-glucosidase showed a broad specificity, that is, containing isoprimeverose in addition to maltose, isomaltose, and alpha-p-NPG. Though this enzyme barely hydrolyzed alpha-p-NPX too, the velocity was very slow. Though both yeast alpha-glucosidases barely hydrolyzed alpha-p-NPX or isoprimeverose too, these substrates were not good for yeast enzymes. On the other hand, two alpha-xylosidases showed narrow specificities, such that the substrates except for alpha-p-NPX and isoprimeverose were not hydrolyzed at all. The action on isoprimerose by Asp. niger alpha-glucosidase was completely the same as that on isomaltose at optimum pH, optimum temperature, inhibition pattern of hydrolyzing activity by 1-deoxynojirimycin, and transfer action pattern. Accordingly, we interpret these results as indicating that the hydrolyzations of isomaltose and isoprimeverose by Asp. niger alpha-glucosidase were catalyzed at the same active site. Asp. niger enzyme that has both alpha-glucosidase activity and alpha-xylosidase activity was shown to be classified in a middle position between alpha-glucosidase and alpha-xylosidase.

The transfer action of α-d-xylosidase I and II from Aspergillus flavus MO-5 on p-nitrophenyl-α-d-xylopyranoside (α-p-NPX) was investigated, as compared with that of commercial α-d-xylosidase (from Bacillus sp.).In reaction mixtures with various concentrations of α-p-NPX, both enzymes (I and II) liberated p-nitrophenol and xylose at low concentrations, and showed transfer products in addition to hydrolyzates at high concentrations. IP-1 and IP-3, IIP-1 and IIP-2, and CP-1 and CP-3 were main transfer products by α-d-xylosidase I, α-d-xylosidase II, and commercial α-d-xylosidase, respectively. They were isolated by active charcoal column chromatography and silica gel column chromatography.Their structures were analyzed by enzymatic digestion, methylation analysis, and 13C-NMR analysis. As the results, IP-1, IIP-2, and CP-1 were found to be the same structure, p-nitrophenyl-4-O-(α-d-xylopyranosyl)-α-d-xylopyranoside. Then, it was proved that the structure of IIP-1 was p-nitrophenyl-3-O-(α-d-xylopyranosyl)-α-x...

Dextrin dextranase (EC 2.4.1.2; DDase), which is produced by Acetobacter capsulatus ATCC 11894, acted on a mixture of stevioside and starch hydrolysate with isoamylase, so that the enzyme was found to convert stevioside to predominantly mono-glucosyl-stevioside (SG1) and di-glucosyl-stevioside (SG2), and little of the stevioside initially added remained. SG1 was separated into two compounds (SG1a and SG1b) by reversed-phase high-pressure liquid chromatography. The structures of SG1a, SG1b, and SG2 were analyzed and concluded to be 13-O-(6-alpha-glucosyl-2-beta-glucosyl-beta-glucosyl)-19-O-beta-glucosyl -steviol, 13-O-[(6-alpha-glucosyl)(2-beta-glucosyl)-beta-glucosyl]-19-O- glucosyl-steviol, and 13-O-[(6-alpha-glucosyl)(6-alpha-glucosyl-2-beta- glucosyl)-beta-glucosyl]-19-O-beta-glucosyl-steviol, respectively. During the reaction for production of glycosyl-steviosides, DDase catalyzes transglucosylations from glucosyl donor compounds to stevioside to be SG1a and SG1b, and to SG1b to be SG2 rapidly forming alpha-1,6 glucosidic linkages. However transglucosylation to SG1a to be SG2 rarely occurred, and the conversions among stevioside and these glycosyl-steviosides were catalyzed by the action of DDase to transfer alpha-1,6 linked glucosyl residues, forming alpha-1,6 linkages.

The substrate specificity of dextrin dextranase (EC 2.4.1.2; DDase) was investigated. This enzyme acted on maltose and isomaltose in addition to starch and dextrin, but did not act on other gluco-disaccharides. When various saccharides were allowed to react with salicin as a glucosyl acceptor, glucosyl residues were transferred to salicin on the reaction with maltose, isomaltose, starch, and dextran as glucosyl donors. On the other hand, when starch as a glucosyl donor was allowed to react with various saccharides, glucosyl residues of starch were transferred to d-glucose, d-xylose, and oligosaccharides that had glucosyl or xylosyl residues at non-reducing termini. Methyl α- and β-d-glucosides also acted as acceptors. Furthermore DDase transferred glucosyl residues from starch to glucose derivatives such as 2-deoxy-, 2-acetamido-2-deoxy-, 3-O-methyl-, and 6-deoxy-d-glucoses. When starch was used as a glucosyl donor, two products formed by transglucosylation to d-glucose as an acceptor were found to be mal...

The structure of dextran synthesized from maltotetraose by dextrin dextranase (EC 2.4.1.2) from Acetobacter capsulatus ATCC 11894 was analyzed. When the Acetobacter dextran (AD) was acetolyzed, glucose and maltose were produced. AD was allowed to react with α-amylases. AD was digested by bacterial saccharifying α-amylase and bacterial liquefying α-amylase, and glucose, maltose, and maltotriose were produced. The structure of the fraction obtained from dextranase-digested AD by activated charcoal chromatography, which did not contain glucose, isomaltose, and isomaltotriose, was investigated by methylation analysis, and the ratio of 2,3,4,6-tetra-O-methyl-: 2,3,4-tri-O-methyl-: 2,3,6-tri-O-methyl-: 2,3-di-O-methyl-alditol acetate was estimated as 22.9:46.8:15.5:14.8. This result indicated the existence of α-1,4 branches and that of α-1,4 linkages in α-1,6 glucosyl linear chains. Native AD was calculated to be constructed with 6.23 branching points and 6.53 α-1,4 linked glucosyl residues per 100 glucosyl uni...

Aromatic poly(amide-imide) with terminal isocyanate groups (PAINCO) was prepared by the polycondensation of trimellitic anhydride and a slight excess of 4,4′-diphenylmethane diisocyanate in N-methyl-2-pyrrolidone (NMP) at 160°C for 20 h. PAI was effectively grafted onto the surface by the reaction of PAI-NCO with carbon black: the percentage of grafting onto FW 200 and Neospectra II was determined to be 41.2 and 39.5%, respectively. When the carboxyl and phenolic hydroxyl groups on carbon black were blocked by treatment with diazomethane, the grafting of PAI-NCO onto the treated carbon black does not proceed. Therefore, it is concluded that PAI-NCO reacts with the carboxyl and phenolic hydroxyl groups on carbon black and PAI is grafted through amide and urethane bonds, respectively. The reaction of PAI-NCO with carbon black was accelerated by the addition of amines as catalyst and by raising of the reaction temperature. Thermogravimetric analysis indicated that PAI-grafted carbon black was stable...