Calcium ion selectivity and isotope effects studied by using benzo-18-crown-6 resins

The chromatography experiments using benzo-18-crown-6 resin were carried out to study isotope effects in calcium adsorption. By the elution technique with hydrochloric acid solution, it was found that the adsorption of calcium depends on the concentration of hydrochloric acid in solution and that 9 M HCl concentration is the appropriate condition for the adsorption of calcium to the cavity of benzo-18-crown-6 of which cavity size is a little larger than the diameter of calcium ion. Thereafter, the isotope fractionation of calcium in the complex formation reaction with 18-crown-6 ether was investigated by using the breakthrough technique of chromatography with above-mentioned synthesized resin and 9 M hydrochloric acid solution. The observed isotope separation coefficient ε=−1 was 1.9 × 10⁻³ for the isotopic pair ⁴⁰Ca/⁴⁸Ca.     

Development of thick layer re-wetting model for brown rice packaged with LDPE and PBT films

A mathematical model was developed to predict a moisture content profile during the thick layer re-wetting process of brown rice unpackaged and packaged with low density polyethylene (LDPE) and polybutylene terephthalate (PBT) films. Model validation was carried out by comparing predicted with measured moisture content derived from relative humidity data obtained from the brown rice re-wetting test for 6 days at 25 °C and 90% RH. The moisture standard errors of the model validation for brown rice packaged in LDPE and PBT films were 0.08% wet basis (wb) and 0.11% wb, respectively. It was concluded that the proposed re-wetting model could successfully describe the thick layer re-wetting of brown rice under the experimental conditions. Using this model, re-wetting simulations were carried out to estimate the time required to condition the moisture content of brown rice at various water vapor permeabilities of film. The cracking ratio of brown rice was also investigated empirically during the re-wetting process of packaged and unpackaged brown rice.     

Flame retardancy of polycarbonate–polydimethylsiloxane block copolymer/silica nanocomposites

This report describes the flame retardancy and the thermal degradation behavior of polycarbonate–polydimethylsiloxane (PC–PDMS) block copolymer/silica nanocomposites. PC–PDMS block copolymer with dimethylsiloxane (DMS) block size 40 units increased the dispersibility of nanosized amorphous silica. Addition of the slight nanosized silica caused the increment of flame retardancy of PC–PDMS block copolymer, and the PC–PDMS block copolymer with 1.0 wt % PDMS had the highest limiting oxygen index value when the nanosized silica was added 0.5 wt %. The maximum rate temperature of the PC–PDMS block copolymer increased with the addition of silica and the maximum loss rate was the lowest when silica content is 0.5 wt %. The monodisperse nanosized silica had an effect that enhances the flame retardant mechanism of PDMS for PC. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3862–3868, 2006     

Development and Applications of High—Frequency Gyrotrons in FIR FU Covering the sub-THz to THz Range

Powerful sources of coherent radiation in the sub-terahertz and in the terahertz frequency range of the electromagnetic spectrum are necessary for a great and continuously expanding number of applications in the physical research and in various advanced technological processes as well as in radars, communication systems, for remote sensing and inspection etc.. In recent years, a spectacular progress in the development of various gyro-devices and in particular of the powerful high frequency (sub-terahertz and terahertz) gyrotron oscillators has demonstrated a remarkable potential for bridging the so-called terahertz power gap and stimulated many novel and prospective applications. In this review paper we outline two series of such devices, namely the Gyrotron FU Series which includes pulsed gyrotrons and Gyrotron FU CW Series which consist of tubes operated in a CW (continuous wave) or long pulse mode, both developed at the FIR FU Center. We present the most remarkable achievements of these devices and illustrate their applications by some characteristic examples. An outlook for the further extension of the Gyrotron FU CW Series is also provided.     

High expression of a synthetic gene encoding potato alpha-glucan phosphorylase in Aspergillus niger

We describe the successful heterologous expression of the Solanum tuberosum alpha-glucan phosphorylase (GP) gene in Aspergillus niger. Special attention was paid to the influence of different codon usage and A+T content in the coding region on GP protein expression. Use of A. niger-preferred codon usage and lower A+T content in a synthetic gene (GP-syn) resulted in a significant improvement in the level of the GP mRNA and a dramatic increase in the quantity of GP protein produced such that it accounted for approximately 10% of the total soluble protein. We suggest that redesigning the primary DNA sequence encoding a desired protein product can be an extremely effective method for improving heterologous protein production in filamentous fungi.     

Control of well‐defined crater structures on the surface of biaxially oriented polypropylene film by adding nucleators

While it is common to add anti‐blocking agents to biaxially oriented polypropylene (BOPP) films for general use in order to prevent blocking against each other, the technology of crater‐like film surface roughness formed on the BOPP films without any additives is well known in the industrial BOPP film areas. Numerous studies have been reported on the crater‐like film surface roughness on the BOPP films since the 1980s, but its formation mechanism and the controlling method of the crater‐like film surface roughness are yet to be clarified. In our previous reports, we presented a new hypothesis of crater formation mechanism from a new point of view on sheet morphology and crater shape on the BOPP film surface. It was strongly influenced by the crystal grain shape in the surface layer of PP sheet. In this report, it was clarified that a nucleator has a big influence on the formation of the crystal grains in the surface layer of PP sheets and on the formation of craters. In addition, craters did not form on the BOPP films stretched from the sheet of which the skin layer with crystal grain was shaved, even though β crystal still remained. It was clarified that the crystal grain is trans‐crystal from the observation using TEM. Therefore, it is concluded that the existence of β crystals in the surface layer of PP sheets is not essential in order to produce craters on BOPP films, but trans‐crystals are necessary to form the craters. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3555–3564, 2013     

Interactive system for optimal position selection of a patch-type R–R interval telemeter

Artificial Life and Robotics - Heart rate variability (HRV) is an indicator of changes in the interval between successive R-waves on the electrocardiogram (ECG), known as R–R intervals (RRI),...     

Hydrothermal degradation of polysaccharides in a semi-batch reactor: product distribution as a function of severity parameter

The naturally occurring polysaccharides, starch and pectic acid, were hydrothermally degraded in a semi-batch reactor coupled with a plug-flow reactor (PFR) to produce valuable chemicals including mono- and oligosaccharides over a temperature range from 160 to 240 °C at 10 MPa. The solid polysaccharide samples were solubilized in a semi-batch reactor, and the water-soluble (WS) components instantly entered the PFR in which further degradation took place. The reaction temperature and/or residence time in the PFR significantly affected the yields of oligosaccharides, monosaccharides and secondary decomposition products, and also the average molecular weight of WS components. The product distributions were expressed with severity, which combines the effects of temperature and time on the progress of the reaction, as a single reaction parameter. Using this parameter, it was found that similar product distributions were obtained at equal levels of severity. The severity parameter enabled easy interpretation of the change in product distribution for these reactions.     

Design of ITO/transparent resin optically selective transparent composite

Optically selective transparent composites were made using ITO particle mixed into a polymer resin. To fabricate the composites, ITO particles were chosen as filler, and Urethane resin (transparent resin) was chosen as a matrix. Using fine (30 nm) and small ITO particle (10 μm), we obtained a composite with optically selective transparent properties. The best sample was 0.2 vol% of ITO fine particle (30 nm) dispersed into the composite, it was not transparent in IR wavelength regions and transmitted more than 80% in visible wavelength region; so an optically selective transparent composite was successfully fabricated.     

Influence of Reflections on Frequency Tunability and Mode Competition in the Second-Harmonic THz Gyrotron

Effect of delayed reflection on operation of a second-harmonic terahertz (THz)-band gyrotron is studied. Theoretical analyses, numerical calculations, and experimental observations for the 0.394-THz Fukui University (FU) and continuous wave (CW) IIB gyrotron are presented. The reflections decrease starting current and expand frequency tunability range owing to excitation of high-order axial modes. They also increase frequency stability, i.e., reduce frequency change due to variation of the magnetic field. In addition, the reflections strongly affect mode competition causing suppress of the second-harmonic mode by the fundamental one and vice versa or, in the case of cooperative mode interaction, mutual power increase.