Analysis of coaxial collinear antenna: recurrence formula ofvoltages and admittances at connections

A method for the analysis of the coaxial collinear antenna made of transposed coaxial sections of arbitrary length is presented. The excitation terms of the integral equation for the current distribution of this antenna are expressed by using a known impressed voltage, and these are computed recursively by computer. Calculated values of current distributions and input impedances are found to agree with measured results, and the validity of the presented method is confirmed. The results derived are applicable to the design of the coaxial collinear antennas of any configuration     

Morphology Control of Silicalite/HZSM-5 Composite Catalysts for the Formation of Para-Xylene

Single- and poly-crystalline silicalite/HZSM-5 core-shell composite catalysts were synthesized by optimizing the silicalite coating conditions. At low molar ratios of SiO₂ (fumed silica) and TPAOH in the coating solutions, a crystal growth of silicalite layer on the HZSM-5 surface was dominant instead of a homogeneous nucleation in the solution. The mass gain after the coating was also inhibited at low molar ratios of silica source and TPAOH. High para-selectivities of silicalite/HZSM-5 composites in the toluene alkylation with methanol were obtained over the single crystal-like silicalite/H-ZSM-5 composite catalyst prepared by one coating process.     

A direct determination method for ethanol concentrations in alcoholic beverages employing a eukaryote double-mediator system

A fast, direct, small-sample measurement method of ethanol determination in alcoholic drinks was established by the application of attractive characteristics of a eukaryote double-mediator (EDM) system, as previously reported. The EDM system, which consists of yeast as well as both hydrophilic and hydrophobic mediators, demonstrates superior sensitivity to organic substances. For high performance, the EDM system was reoptimised for ethanol determination with a small sample volume of only 3 μL and a short incubation time of 5 min. Under optimal conditions, a practical calibration curve for ethanol determination in alcoholic beverages was obtained between 0.5 and 50 v/v% (r = 0.997, 9 points, n = 3, average of relative standard deviation, RSD_av = 2.75%), with a detection limit of 0.5 v/v%. To characterise our ethanol determination method, the effects of pH, organic substances, carbon dioxide gas, or sodium sulphite on EDM responses were studied in detail. No notable effects of pH on EDM responses were observed; however, glucose and ascorbic acid strongly increased the EDM response to ethanol. Real sample applications were mainly performed using distilled alcoholic drinks (shochu, brandy, vodka, gin, and whisky) and several kinds of beer and similar beverages (lager, draft, low-malt, non-malt, and sugar-free). When the results with sugar-free beverages were compared with those obtained by the available enzymatic-spectrophotometric (ES) method, an excellent correlation was obtained (r = 0.990, 7 points, n = 3, RSD_av of the EDM method = 7.90%), with an excellent slope of 1.05. Finally, a yeast suspension stored at 4 °C was stable for at least 7 days, with a response reduction of 88% (RSD_av for five testing days = 4.8%).     

Preclinical and Clinical Evidence of Therapeutic Agents for Paclitaxel-Induced Peripheral Neuropathy

Paclitaxel is an essential drug in the chemotherapy of ovarian, non-small cell lung, breast, gastric, endometrial, and pancreatic cancers. However, it frequently causes peripheral neuropathy as a dose-limiting factor. Animal models of paclitaxel-induced peripheral neuropathy (PIPN) have been established. The mechanisms of PIPN development have been elucidated, and many drugs and agents have been proven to have neuroprotective effects in basic studies. In addition, some of these drugs have been validated in clinical studies for their inhibitory PIPN effects. This review summarizes the basic and clinical evidence for therapeutic or prophylactic effects for PIPN. In pre-clinical research, many reports exist of neuropathy inhibitors that target oxidative stress, inflammatory response, ion channels, transient receptor potential (TRP) channels, cannabinoid receptors, and the monoamine nervous system. Alternatively, very few drugs have demonstrated PIPN efficacy in clinical trials. Thus, enhancing translational research to translate pre-clinical research into clinical research is important.     

Microstructural Control of BaTiO3 Thick Film Fabricated by Utilizing Slide-Off Transfer Printing

Effects of fabrication conditions on the microstructure of thick BaTiO₃ films have been investigated by employing slide-off transfer printing technique. Formation of dense films with good adhesive properties was difficult when screen-printing was employed in preparing the slide-off transfer sheets (BaTiO₃ green films), irrespective of the kind of solvents used for the slurries. On the other hand, relatively dense films could be fabricated from the slide-off transfer sheet prepared by spin-coating of the slurries consisting of fine BaTiO₃ powder (particle size: ca. 0.1 m), printing oil, and 2-propanol, though cracks formed obviously. Co-addition of large BaTiO₃ particles (particle size: ca. 0.5 m) was very effective for reducing the formation of cracks, and homogenous and dense films could be fabricated by controlling the additive amount of the large particles.     

Oxygen-Sensing Properties of Spinel-Type Oxides for Stoichiometric Air/Fuel Combustion Control

The temperature dependence of electrical resistance of several spinel-type oxides was measured in exhaust gases of air-methane combustion, to evaluate the potential of the oxides as an air/fuel stoichiometric oxygen sensor. The results are discussed in terms of sensitivity and response time at the stoichiometric combustion point. It was found that the sensitivity as well as the response time is markedly affected by point defect structures of the oxide specimens. The response time is also related to the catalytic activity of the oxides for complete oxidation of methane. Among the specimens studied, the ZnCr₂O₄+ Cr₂O₃ (1.0:0.1 molar ratio) is the most promising as the oxygen sensor, because it exhibits the largest resistance changes of more than 3 orders of magnitude and shortest response times of about 0.5 s when the combustion mixture is switched between the air-rich versus fuel-rich composition.     

Fabrication of hollow alumina microspheres via core/shell structure of polymethylmethacrylate/alumina prepared by mechanofusion

Core/shell microspheres of polymethylmethacrylate coated with Al₂O₃ or a mixture of Al₂O₃ and SiO₂ nanoparticles have been successfully prepared by a mechanofusion system. The microspheres were then subjected to removal of PMMA by firing in air, followed by sintering at 1600°C for 3 h. The shell structure was destroyed after the sintering when the shell layer consisted of only Al₂O₃. The addition of SiO₂ was found to be effective for maintaining the original shell structure, while the shell size expanded slightly and a hole was formed in each hollow microsphere during the removal process of PMMA.     

Zinc Oxide Varistor Gas Sensors: I, Effect of Bi2O3 Content on the H2-Sensing Properties

Current ( I )-voltage ( V ) characteristics of porous ZnO varistors with different Bi₂O₃ content have been investigated in air as well as in H₂-air mixtures in the temperature range room temperature (RT)-600°C. The I-V characteristics measured at RT remained unchanged in the presence of H₂, but the breakdown voltage clearly shifted to a lower electric field in the temperature range 400–600°C. The breakdown voltage decreased with increasing H₂ concentration in air. The optimum amount of Bi₂O₃ for the largest decrease was found to be 1.0 mol%. Thus, ZnO varistors can be used as a new type of H₂ sensor. The results presented in this study also suggest the important role of excess oxygen ions existing at the ZnO-ZnO grain boundaries in developing the Schottky barrier as well as in the H₂-sensing mechanism of the varistors.     

Production of ultra-fine silicon powder by the arc plasma method

A method of producing ultra-fine silicon powder is described. The most probable particle size produced by this method was estimated to be about 30 nm by TEM observation and X-ray diffraction. The powder was produced by an arc plasma method. This method is quite feasible for bulk continuous production of ultra-fine powder. Mechanisms of the production of the powder are also discussed. The principal mechanism for this ultra-fine powder production is attributed to the increase of the partial pressure of nitrogen (or hydrogen) gas by an arc plasma.