Thermal and gas permeation properties of copolymers derived from 3‐methacryloxypropyltris(trimethylsiloxy)silane and adamantyl group‐containing methacrylate derivatives

Novel copolymer membranes derived from three types of adamantyl group‐containing methacrylate derivatives and 3‐methacryloxypropyltris(trimethylsiloxy)silane (SiMA) were synthesized via free radical polymerization. The thermal and permeation properties of these copolymer membranes were investigated. Copolymer membranes with less than 11.9 mol % adamantane content exhibited good membrane forming abilities that are suitable for permeation measurement. The decomposition temperature of all copolymers increased up to approximately 40–80°C with increasing adamantane content compared with poly(SiMA). Moreover, the glass transition temperature (T_g) of all copolymers increased up to approximately 46–60°C with increasing adamantane content compared with the theoretical value, which was estimated from Fox equation. 1‐Adamantyl methacrylate copolymer had the highest fractional free volume among the three types of adamantly group‐containing methacrylate derivatives. The gas permeability coefficient of this copolymer increased by 22–45% with increasing adamantane content compared with that of poly(SiMA). © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43129.     

Effect of Tensile Stress on Hall Coefficients of Nickel-Base Superalloys

This paper reports on Hall Effect measurements on nickel-base superalloys and their stress dependency. The work is motivated by the desire to develop a nondestructive method of characterizing the near-surface protective residual stress in metals. Our approach is based on the assumption that the Hall coefficient deviates under the stress. It is anticipated that stress measurements based on the Hall Effect are less contaminated by cold work and other effects than conductivity-based measurements such as eddy current. The paper focuses on the two superalloys, Inconel 718 and Inconel 600. The challenge is that Hall coefficients are small in metals, and the stress-induced changes are even smaller. To measure the small effect, the lock-in technique was used, with AC injected current and AC magnetic field. It was found that the Hall coefficients indeed vary proportionally to the stress. The proportionality coefficients are significantly larger than what are estimated from the volumetric effect in a free carrier gas model. The temperature and injected current dependences of the Hall coefficients were also measured, while no dependence on the magnetic flux density was observed.     

Securing an optimum operating field without undesired tissue damage in neurosurgery

In neurosurgery, surgeons sometimes retract brain tissue to prepare an operating field around a lesion. In addition, they are required to plan a safe surgical pathway for deep-brain regions while considering tissue damage caused by excessive stress. The goal of this study is to develop a technique for automatically generating a surgery pathway for lesions in the deep-brain region, focusing on securing an operating field around the lesion as a first step and also considering brain tissue deformation. In previous studies, securing the operating field has been treated as a single-objective optimization problem in order to maximize the viewable area of the lesion. However, in this study, the task of securing the operating field is formulated as a multi-objective optimization problem. Using a technique that combines finite element analysis and an optimization method, the principal stress on the brain is constrained to less than a certain threshold value, and the position and orientation of the surgical instrument are optimized for safe retraction of the brain according to various weighting factors.     

Recursive Calculation of Connection Formulas for Systems of Differential Equations of Okubo Normal Form

We study the structure of analytic continuation of solutions of an even rank system of linear ordinary differential equations of Okubo normal form (ONF). We develop an adjustment of the method for evaluating the connection formulas of the Gauss hypergeometric function by means of the Euler integral to the system of ONF. We obtain recursive relations between connection coefficients for the system of ONF and ones for the underlying system of ONF of half rank.     

Technologies and applications of Al‐free high‐power laser diodes

We report high‐power technologies in 0.8‐µm Al‐free InGaAsP/InGaP laser diodes. To realize the high‐power operation, the improvement of catastrophic optical mirror damage (COMD) power density level is required. In addition to the use of low surface recombination velocity of Al‐free materials, optimization of waveguide thickness in broad waveguide structure with tensile‐strained barriers and current blocking structure near facets has led to high COMD power density level. Highly stable operation of Al‐free laser diodes with these structures has been obtained over 2500 hours at 2 W from a stripe width of µm. Applications of high‐power laser diodes are also described. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(1): 53–59, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20286     

PRODUCTION OF SHOCHU ON A COMMERCIAL SCALE FROM POST-DISTILLATION SLURRY BY A NEWLY DEVELOPED RECYCLING PROCESS

During commercial scale fermentation for the production of rice shochu using post-distillation slurry in place of the first-stage mash, it was difficult to stir the mash from the first to the third day because of the high viscosity of the mash. Shochu was therefore fermented with a two-step addition of cooked rice, adding rice on the first and third days, to reduce the viscosity of mash during the first few days. Even though the ethanol concentration of the mash after 9 d was 17.2 v/v% and was a little lower than that obtained in laboratory scale tests, the yield of pure ethanol was 473 ml kg^?1 of rice and this value was higher than the average value (450 ml kg^?1) when shochu is made in the standard manner on a commercial scale. The shochu produced on a commercial scale by the newly developed recycling process was very mild and smooth, and received high scores in sensory tests.     

Improved method for evaluating antenna performance in mobile environment with consideration of polarization and phase

The paper presents an improved method for evaluating antenna performance in a multipath propagation environment. It demonstrates, theoretically and experimentally, that by using polarization and phase terms of the incident field and the antenna system in the evaluation of the antenna effective gain (AEG), the AEG can be evaluated more efficiently as compared with the conventional method. First, a theoretical expression of the received power is given by using the open-circuit voltage at the antenna terminals, in which both the polarization and the phase of the incident field and antenna gain patterns are explicitly used. Secondly, a newly developed system for the measurement of field parameters, such as polarization and phase as well as amplitude, is introduced. Thirdly, incident field parameters measured in urban and suburban areas of Tokyo are described. It was confirmed that major incident waves were counted in up to five or six directions at a mobile terminal and their polarizations and phases were different depending on the direction of incidence. Also, measurement of the antenna gain patterns of the latest personal digital cellular handset at a talk position finds the dependence of the AEG on polarization and phase, which were significantly varied by the body effect. Finally, the AEG is evaluated based on the method introduced here, and its usefulness is compared with that of the conventional method.     

Nb3Sn single-phase targets for fiber-reinforced-superconductors and technique of preparing superconducting films without post annealing

A new type of superconductor is being developed for the application of high-field pulsed superconducting magnets, which are called fiber-reinforced-superconductors (FRS). A filament of FRS consists of a reinforcement fiber with high elastic modulus and a superconducting layer around it. The strain can be reduced against electromagnetic force because of highelastic modulus fibers. If Nb₃Sn target is utilized, the preparation process of FRSs is shortened and there is the possibility to produce Nb₃Sn layer which leads to high current density because of its uniform stoichiometric Nb₃Sn layer. This paper presents first a technique of preparing a single-phase target of Nb₃Sn to produce superconducting layers on reinforcement fibers of FRSs. Mixture of niobium and tin powder was reacted in a furnace filled with argon gas to be Nb₃Sn, and then it was broken and cast into a stoichiometric target with a diameter of 77 mm. The critical temperature of the target itself was 17.5 K. The thin film deposited with the target showed no superconductivity without post annealing, but it had critical temperature from 14.5 K to 12.5 K after heat treatment. Second, a new target containing rich tin was prepared and the film deposited with it had superconductivity without post annealing.     

Characteristics of LSM combined propulsion,levitation and guidance

In commercializing the superconducting maglev system, it is important to reduce the cost, especially that of ground coils installed all along the guideway. The ground coils designed for Yamanashi test track under construction are composed of both octagonal-shaped null-flux coils for EDS (Electrodynamic Suspension) and double-layered armature coils of LSM (Linear Synchronous Motor). The former reduces the magnetic drag of the running resistance, and the latter reduces the electromagnetic fluctuation in the superconducting coils. In addition, the octagonal-shaped coils can generate propulsion force by being connected to the power supply. This system can generate levitation force, guidance force and propulsion force by the same ground coils. Therefore this system is expected to reduce the cost of ground coils, the number of which is decreased. This paper presents the principle and analytical formula of the combined propulsion, levitation and guidance system (PLG system), including one for angles. In addition, using numerical examples, the characteristics of this system are expressed.