Carbonization of coals to produce anisotropic cokes: 3. Evaluation of low-rank bituminous and subbituminous coals by single and co-carbonizations with pitch

Single carbonizations and co-carbonizations of 17 low-rank bituminous and subbituminous coals have been studied to evaluate their suitability as sources of blast furnace coke in terms of pore-wall profile and anisotropic development within the cokes. Co-carbonizations suggest the possible use of low-rank coals which from single carbonizations would not have been considered suitable. To evaluate semi-quantitatively the coke quality, two structural characteristics of the cokes produced by single and co-carbonizations are graded on a scale of 1 to 5. Overall assessments for each coal are plotted against the atomic H/C and 0/C ratios of the original coals. Although there are a few exceptions, coals with similar assessments are located in the same region of the plot, indicating that, to a first approximation, the H/C and 0/C ratios are suitable indicators of the single and co-carbonization properties of a coal. The presence of cations in the coal appears to be an additional factor influencing the carbonization properties and may explain the exceptional behaviour of some coals. Removal of these cations by pretreatment of the coals improves the carbonization properties.     

Stress Analysis of T-type Butt Adhesive Joint Subjected to External Bending Moments

Stress distributions and displacements at the interface between an adhesive and an adherend are examined when a T-type butt adhesive joint, in which two thin plates are joined, is subjected to an external bending moment. In the analyses, general representations of the stresses and the displacements are given using a two-dimensional theory of elasticity in the case where two dissimilar plates are joined. Next, in the case of plates with the same material, effects of Young's modulus of plates to that of an adhesive and the thickness of the adhesive on the stress distribution are made clear by numerical computations. For verification, experiments are performed and an analytical result is in a fairly good agreement with an experimental one.     

Fabrication of gold nanoparticle pattern using imprinted hydrogen silsesquioxane pattern for surface-enhanced Raman scattering

This is the first report of surface-enhanced Raman scattering (SERS) substrate fabrication using a combination of imprinted hydrogen silsesquioxane (HSQ: HSiO_3/2) patterns and self-assembly of gold nanoparticles (AuNPs). To assemble the AuNPs inside the imprinted HSQ pattern, it is important to understand the interactions between AuNPs and AuNPs, and those between AuNPs and HSQ. The authors investigated the effects HSQ surface charges on the self-assembly of AuNPs. It was found that the negatively charged AuNPs were successfully assembled according to the geometry of the negatively charged HSQ pattern. In addition, it was shown that the SERS substrate fabricated from an HSQ consisting of an inorganic polymer was suitable for organic chemical analysis, by comparing it with a substrate fabricated using an organic polymer.     

Directed evolution of Pseudomonas aeruginosa lipase for improved amide-hydrolyzing activity

A lipase from Pseudomonas aeruginosa was subjected to directed molecular evolution for increased amide-hydrolyzing (amidase) activity. A single round of random mutagenesis followed by screening for hydrolytic activity for oleoyl 2-naphthylamide as compared with that for oleoyl 2-naphthyl ester identified five mutants with 1.7-2.0-fold increased relative amidase activities. Three mutational sites (F207S, A213D and F265L) were found to affect the amidase/esterase activity ratios. The combination of these mutations further improved the amidase activity. Active-site titration using a fluorescent phosphonic acid ester allowed the molecular activities for the amide and the ester to be determined for each mutant without purification of the lipase. A double mutant F207S/A213D gave the highest molecular activity of 1.1 min(-1) for the amide, corresponding to a 2-fold increase compared with that of the wild-type lipase. A structural model of the lipase indicated that the mutations occurred at the sites near the surface and remote from the catalytic triad, but close to the calcium binding site. This study is a first step towards understanding why lipases do not hydrolyze amides despite the similarities to serine proteases in the active site structure and the reaction mechanism and towards the preparation of a general acyl transfer catalyst for the biotransformation of amides.     

A Stress Analysis of Butt Adhesive Joints Under Torsional Loads

The stress distribution and the displacement are examined when a butt adhesive joint, in which two dissimilar tubular shafts are joined, is subjected to a torsional load. In the analyses, general representations of the stresses and the displacements are given as a torsion problem when two dissimilar tubular shafts are band-adhesively bonded. Next, in the case of shafts with the same material, effects of the ratio of the shear modulus of an adhesive to that of shafts, the thickness of the adhesive and the bonded position of band-adhesive on the stress distribution are made clear by numerical computations. Moreover, when solid shafts are joined, these effects are made clear by the similar analyses and numerical computations.     

Electrochemical behavior of poly(3-hexylthiophene). Controlling factors of electric current in electrochemical oxidation of poly(3-hexylthiophene)s in a solution

Electrochemical response of regio-random and regio-controlled poly(3-hexylthiophene), P3HexTh, was investigated by cyclic voltammetry. P3HexTh underwent electrochemical oxidation at about 0.4 V vs. Ag⁺/Ag in a THF solution, and the peak anode electric current, i_pa, was proportional to the sweeping rate v; i_pa=const×v^1/2. These data indicated that diffusion of the P3HexTh molecule in the solution was important to determine i_pa. Application of a Matsuda's equation with assumptions gave a diffusion coefficient, D, of about 1×10⁻⁷ cm² s⁻¹ at molecular weight of about 5000, and the D value steeply decreased with increase in the molecular weight.     

Enzyme-linked immunosorbent assay for nonylphenol using antibody-bound microfluid filters in vertical fluidic operation

We developed an enzyme-linked immunosorbent assay for an endocrine disrupter, nonylphenol, using a microreactor composed of two reaction vessels stacked vertically through a microfluid filter. The filters constructed by deep X-ray lithography possessed 2100 through-bores (phi40 x 200 microm) in polymethylmethacrylate sheets (phi3 mm), which are appropriate for biochemical reactions. Through the optimization of the immunoassay, nonylphenol was quantitatively detected at the range of 0.1-10 ng/ml.     

Effect of fabrication process on characteristics of phosphorescence organic light emitting diodes with methoxy-substituted starburst low-molecule as a host

The effect of dry process and wet process on the characteristics of phosphorescence organic light-emitting devices (OLEDs) employing a phosphorescent dye fac-tris(2-phenylpyridine) iridium(III) (Ir(ppy)₃) doped into a methoxy-substituted starburst low-molecule material methoxy-substituted 1,3,5-tris[4-(diphenylamino) phenyl]benzene (TDAPB) are investigated. The FT-IR and absorption spectra of TDAPB films fabricated by a dry process, and a wet process are almost same, and the PL spectra of those films are different. The carrier transport capability of TDAPB by a dry process is lower than that by a wet process. The photoluminescence intensity of Ir(ppy)₃ doped in TDAPB fabricated by a wet process is higher than that by a dry process. A maximum external current efficiency of more than 20 cd/A and luminance of more than 10,000 cd/m² were obtained. Maximum luminance of devices monotonously decreases with increasing the thickness of a dry-processed emitting layer. The main emission zone of the OLED was located in almost at the center of the emitting layer. The improvement of device performance in the OLED fabricated by a wet process was achieved due to the high efficient energy transfer from TDAPB to Ir(ppy)₃, high carrier transporting capability and the formation of homogeneous film, compared with that fabricated by a dry process.     

Development of an S-doped titania nanotube (TNT) site-selectively loaded with iron(III) oxide and its photocatalytic activities

We investigated an S-doped titania nanotube (TNT) loaded with Fe₂O₃ nanoparticles in order to improve photocatalytic activity of S-doped TNT under visible light irradiation. S-doped TNT was successfully prepared using the solid-phase method at 350 °C under aerated conditions. S-doped TNT showed photoabsorption in the 400–500 nm visible light region and showed photocatalytic activity for oxidation of acetaldehyde under visible light irradiation. Loading of Fe₂O₃ on S-doped TNT remarkably improved the photocatalytic activity of S-doped TNT. PA spectra measurement, which was performed in order to elucidate the mechanism of activity improvement, showed that the efficiency of charge separation between photoexcited electrons and holes was improved because the electrons were trapped by Fe₂O₃. Enhancement of photocatalytic activity was strongly dependent on the site of Fe₂O₃ nanoparticles loaded on TNT. PA spectra measurement showed that the photoexcited electrons transferred to Fe₂O₃ from S-doped TNT under UV light irradiation or to S-doped TNT from Fe₂O₃ under visible light irradiation.