Effect of CaO and SiO2 addition on magnetic properties of anisotropic Ba-Zn system W-type hexagonal ferrite magnets

An experiment was carried out to investigate the effect of CaO and SiO₂ addition on the magnetic and physical properties of anisotropic Ba-Zn W-type hexagonal ferrite magnets. It was found that magnetic properties of BaO.2ZnO.8Fe₂O₃ compounds added with CaO and SiO₂ were improved. The optimum conditions of typical specimens are as follows: chemical analysis composition-Ba_0.857 Zn_1.643 Ca_0.150 Si_0.266 Fe²⁺_0.030 Fe³⁺_15.857 O₂₇; semisintering condition-1275°C × 1.0 h in air; sintering condition- 1250°C × in air, magnetic and physical properties are J_m = 0.436 T, J_r = 0.393 T. H_cj = 64.4 kA/m, H_cB = 64.1 kA/m, (BH)_max = 16.1 kJ/m³, T_c = 357°C, H_A = 971 kA/m, K_A = 2.03 × 10⁵ J/m³ and n_B = 33.2 μ_B.     

The disk cure test—an evaluation method for flow and curing characteristics of thermosetting molding compounds

A new and useful method, the Disk Cure Test, has been developed for evaluating the curing characteristics and moldability of thermosetting resins. The change of flowability during heating in a thin state at given temperatures is examined as a measure of curing rate. The optimum test conditions were established. The feature of this method was also clarified by comparing it with the conventional tests, such as Brabender plastometry, Curelastometry, and solvent-extraction. Based on this information on curing, the moldability and the optimum molding conditions were established for various commercial and laboratory compositions, including phenolics, aminos, diallyl phthalates, epoxies, and poly(bismaleimide).     

Site-selective blocking of PCR by a caged nucleotide leading to direct creation of desired sticky ends in the products

In order to terminate the polymerase reaction at a desired position, a caged thymine derivative--4-O-[2-(2-nitrophenyl)propyl]thymine--was incorporated into PCR primers. In the PCR cycles, the elongation of the nascent strand (5'-->3' direction) by polymerase was site-selectively terminated at the 3'-side of T(NPP). Accordingly, predetermined protruding ends were obtained after the removal of the protecting group by short UVA irradiation. Recombinant vectors coding the GFP gene were successfully prepared by direct ligation of these light-assisted cohesive-ending PCR (LACE-PCR) products with scission fragments obtained by use either of restriction enzymes or of artificial restriction DNA cutters and were used for transformation of E. coli.     

Simulation of charge effects on density maps obtained by high-resolution electron crystallography

Atomic scattering factors for electrons are strongly affected by the charge status of the scattering atoms. The difference in scattering factors for charged and neutral atoms is most pronounced in the resolution range below 5 A. As a result of the negative scattering factors of negatively charged atoms in the low-resolution range, charged glutamate or aspartate residues produce weaker densities in electron crystallographic maps than their neutral forms. Such charge effects were indeed observed in an experimental map of bacteriorhodopsin. Here we present mathematical simulations of this charge effect on electron crystallographic density maps that corroborate the experimental results. For the simulations, we first evaluated the errors introduced by approximating atomic scattering factors for neutral and charged atoms by Gaussians. The simulations then showed that the effect of a polarized pair of oxygen and hydrogen atoms on the density (polarization effect) was much smaller than that expected from the individual charged atoms (charge effect), due to charge compensation. Still, density maps obtained by electron crystallography are expected to show slightly elongated features toward the positively charged atoms.     

Arsenate removal from water by a weak-base anion exchange fibrous adsorbent

A weak-base anion exchange fiber named FVA with primary amino groups for selective and rapid removal of arsenate species was prepared by means of electron irradiation induced liquid phase graft polymerization of N-vinylformamide onto polyethylene coated polypropylene fibers and by the subsequent alkaline hydrolysis of amide group on the grafted polymer chains. Two types of FVA were prepared. One was a non-woven cloth type named FVA-c for the batch-mode study, which clarified that uptake of arsenate species decreases with an increase in pH, and chloride and sulfate do not strongly interfere with uptake of arsenate species different from conventional anion exchange resins based on crosslinked polystyrene matrices. The other was a filamentary type one named FVA-f used in the column-mode study, which clarified that arsenate species were successfully removed from neutral pH arsenate solutions containing 1.0-99 mg of As/L at feed flow rates of 100-1050 h(-1) in space velocity (SV). The most important findings are that the 1% breakthrough point in uptake from the arsenate solution containing 1.0mg of As/L at the high feed flow rate of 1050h(-1) in SV was as large as 4670 bed volumes, giving the 1% breakthrough capacity of 0.298 mmol/g of FVA-f. Adsorbed arsenate was able to be quantitatively eluted with 1M hydrochloric acid and FVA-f was simultaneously regenerated. Then, the repeated use of FVA-f was possible.     

Geological characteristics of landslides triggered by the 2016 Kumamoto earthquake in Mt. Aso volcano,Japan

On 16 April 2016, a M_w 7.0 earthquake occurred in Kumamoto city, Japan. The main shock induced two large landslides, namely the Aso Bridge landslide and the Aso Volcanological Laboratory landslide. Their topographical and geological conditions and motion features were investigated by using an unmanned aerial vehicle (UAV) and portable dynamic cone penetration tests (PPTs). The Aso Bridge landslide lies between elevations of 385 m and 725 m, with a total estimated volume of about 1,980,000 m³. The main body is composed of cohesive soil with lapilli and block. The Aso Volcanological Laboratory landslide lies on a slope between 483 m to 582 m, and the total volume is about 81,000 m³, with an average thickness of 4.5 m. The main body is composed of Kusasenrigahama volcanic pumice tephra beds. The material compositions and deposits of both landslides have low cohesion and easily induced shear failure for the two landslides. The sliding distance of the Aso Bridge landslide was long, the sliding direction almost unchanged from the scarp to the toe, and the sliding speed was rapid. The sliding distance of the Aso Volcanological Laboratory landslide, however, was short, the sliding direction changed from the N-direction at the scarp to the NW-direction at the toe, and the sliding speed was slow.

     

Effect of adding Pd nanoparticles to dimercaptan-polyaniline cathodes for lithium polymer battery

The electrochemical properties of 2,5-dimercapto-1,3,4-thiadiazole (DMcT)—polyaniline (PAn) composite films containing Pd nanoparticles (average diameter: 28 nm) were investigated. Compared to DMcT–PAn composite film, the DMcT–PAn composite film containing Pd nanoparticles showed enhanced redox current and discharge capacity. The enhanced activity is attributed to the nanosize dispersion of the Pd catalyst particles within the DMcT–PAn matrix. UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS) results confirmed the interactions between DMcT and Pd nanoparticles. We have obtained the positive effect of Pd nanoparticles addition on the redox activity of the DMcT–PAn composite.     

Air/steam flow and steam wetness dependence on acoustic resonance in safety relief valves

Many experimental studies related to the flow-induced acoustic resonance closed side branches have been reported. However, few studies have reported on the effects of air/steam flow and steam wetness dependence on fluctuating pressure amplitude. Therefore, we investigated the effect of air/steam flow and steam wetness dependence on fluctuating pressure amplitude by conducting a high temperature and high pressure tests at the Hitachi Utility Steam Test Leading Facility (HUSTLE). The test section consisted of a main pipe and a side branch. The side branch was mounted on the long straight main pipe. Fluctuating pressures at the end face of the side branches were measured. The following two results were obtained; the first is that the air/steam flow had little effect on the fluctuating pressure amplitude normalized by dynamic pressure and frequency normalized by the resonance frequency; the second is that under the acoustic resonance (St = 0.41) and non-resonance (St = 0.55) conditions, fluctuating pressure and frequency changed little with steam wetness. The steam wetness during the boiling water reactor operation was less than 0.1%; thus, there was no effect of steam wetness on the acoustic pressure amplitude and the frequency under this operating condition.     

Comprehensive approach to intrinsic charge carrier mobility in conjugated organic molecules, macromolecules, and supramolecular architectures

Si-based inorganic electronics have long dominated the semiconductor industry. However, in recent years conjugated polymers have attracted increasing attention because such systems are flexible and offer the potential for low-cost, large-area production via roll-to-roll processing. The state-of-the-art organic conjugated molecular crystals can exhibit charge carrier mobilities (μ) that nearly match or even exceed that of amorphous silicon (1-10 cm(2) V(-1) s(-1)). The mean free path of the charge carriers estimated from these mobilities corresponds to the typical intersite (intermolecular) hopping distances in conjugated organic materials, which strongly suggests that the conduction model for the electronic band structure only applies to μ > 1 cm(2) V(-1) s(-1) for the translational motion of the charge carriers. However, to analyze the transport mechanism in organic electronics, researchers conventionally use a disorder formalism, where μ is usually less than 1 cm(2) V(-1) s(-1) and dominated by impurities, disorders, or defects that disturb the long-range translational motion. In this Account, we discuss the relationship between the alternating-current and direct-current mobilities of charge carriers, using time-resolved microwave conductivity (TRMC) and other techniques including field-effect transistor, time-of-flight, and space-charge limited current. TRMC measures the nanometer-scale mobility of charge carriers under an oscillating microwave electric field with no contact between the semiconductors and the metals. This separation allows us to evaluate the intrinsic charge carrier mobility with minimal trapping effects. We review a wide variety of organic electronics in terms of their charge carrier mobilities, and we describe recent studies of macromolecules, molecular crystals, and supramolecular architecture. For example, a rigid poly(phenylene-co-ethynylene) included in permethylated cyclodextrin shows a high intramolecular hole mobility of 0.5 cm(2) V(-1) s(-1), based on a combination of flash-photolysis TRMC and transient absorption spectroscopy (TAS) measurements. Single-crystal rubrene showed an ambipolarity with anisotropic charge carrier transport along each crystal axis on the nanometer scale. Finally, we describe the charge carrier mobility of a self-assembled nanotube consisting of a large π-plane of hexabenzocoronene (HBC) partially appended with an electron acceptor. The local (intratubular) charge carrier mobility reached 3 cm(2) V(-1) s(-1) for the nanotubes that possessed well-ordered π-stacking, but it dropped to 0.7 cm(2) V(-1) s(-1) in regions that contained greater amounts of the electron acceptor because those molecules reduced the structural integrity of π-stacked HBC arrays. Interestingly, the long-range (intertubular) charge carrier mobility was on the order of 10(-4) cm(2) V(-1) s(-1) and monotonically decreased when the acceptor content was increased. These results suggest the importance of investigating charge carrier mobilities by frequency-dependent charge carrier motion for the development of more efficient organic electronic devices.