Angle-resolved soft X-ray emission and absorption spectroscopy of hexagonal boron nitride

Angle-resolved soft X-ray emission and absorption spectra in the BK and NK regions of hexagonal BN were measured using polarized synchrotron radiation. The take-off/incident-angle-dependence on the spectral features in both X-ray emission and absorption is clearly observed. The configuration of the sigma and pi orbitals, which were calculated using discrete variational (DV)-Xalpha molecular orbital calculations, explains the angle-resolved soft X-ray emission and absorption spectra. The relative peak intensity of the 394-eV peak in the NK X-ray emission provides useful information about the BN layer ordering.     

Accuracy of the Sampling Moiré Method and its Application to Deflection Measurements of Large-Scale Structures

Measuring accurate displacement distributions for large-scale structures is an important issue and a very challenging task. Recently, a simple and accurate phase measurement technique called sampling moiré method [Exp Mech 50–4:501–508, (2010)] has been developed for small-displacement distribution measurements. In this method, the phase distribution of moiré fringes can be analyzed from a single grating image by simultaneously performing down-sampling image processing and intensity-interpolation to generate multiple phase-shifted moiré fringe images. In addition, the phase of the original grating can also be obtained from the phase of the moiré fringe by adding the phase of the sampling grating. In this study, the measurement accuracy of the sampling moiré method was analyzed through computer simulations and a displacement measurement experiment. Four factors of the sampling moiré method were investigated, including the sampling pitch, the order of the intensity-interpolation, random noise, and the form of grating. The results show that determining the optimal sampling pitch is an important factor for obtaining better results but it is not critical. In addition, a practical application of the sampling moiré method is presented that involves a deflection measurement on a 10-meter-long crane. The experimental results demonstrate that submillimeter deflections of the crane can be successfully detected.     

Measurement of the absolute branching fraction of Ds+ --> tau+ nutau decay

Using a sample of tagged D(s)(+) decays collected near the D(s)(*+/-)D(s)(-/+) peak production energy in e(+)e(-) collisions with the CLEO-c detector, we study the leptonic decay D(s)(+)-->tau(+)nu(tau) via the decay channel tau(+)-->e(+)nu(e)nu(tau). We measure B(D(s)(+)-->tau(+)nu(tau))=(6.17+/-0.71+/-0.34)%, where the first error is statistical and the second systematic. Combining this result with our measurements of D(s)(+)-->mu(+)nu(mu) and D(s)(+)-->tau(+)nu(tau) (via tau(+)-->pi(+)nu(tau)), we determine f(D(s))=(274+/-10+/-5) MeV.     

Massive CP theory from a microscopic model for doped antiferromagnets

A path-integral for the t–J$t\text{–}J$ model in two dimensions is constructed based on Dirac quantization, with an action found originally by Wiegmann [P. Wiegmann, Phys. Rev. Lett. 60 (1988) 821; P. Wiegmann, Nucl. Phys. B 323 (1989) 311]. Concentrating on the low doping limit, we assume short range antiferromagnetic order of the spin degrees of freedom. Going over to a local spin quantization axis of the dopant fermions, that follows the spin degree of freedom, staggered CP¹ fields result and the constraint against double occupancy can be resolved. The staggered CP¹ fields are split into slow and fast modes, such that after a gradient expansion, and after integrating out the fast modes and the dopant fermions, a CP¹ field-theory with a massive gauge field is obtained that describes generically incommensurate coplanar magnetic structures, as discussed previously in the context of frustrated quantum antiferromagnets. Hence, the possibility of deconfined spinons is opened by doping a colinear antiferromagnet.     

Radical Polymerization of methacrylates with an adamantane‐like rigid core derived from naturally occurring myo‐inositol

Trimethacrylate and dimethacrylate with rigid adamantane‐like cores were synthesized from myo‐inositol orthoester, and their radical homopolymerization and copolymerization with methyl methacrylate (MMA) were investigated. The radical homopolymerization of trimethacrylate yielded a networked polymer with higher thermal stability than that of a networked polymer synthesized by radical homopolymerization of 1,3,5‐cyclohexanetriol‐derived trimethacrylate, demonstrating the effect of adamantane‐like core rigidity on the increase in thermal stability. Further, dimethacrylate underwent cyclopolymerization, forming a macrocyclic structure in the repeating unit, as the two methacrylate groups were oriented axially from the rigid orthoester‐core and thus located close to each other. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2411–2420     

Viscosity monitoring with a piezoelectric quartz crystal and its application to determination of endotoxin by gelation of limulus amebocyte lysate

A piezo-electric quartz crystal is used to monitor viscosity changes in a liquid. A resistance, included in the electrical equivalent circuit of the crystal, and the resonance frequency change of the crystal, measured by an impedance analyzer, are used for the viscosity measurement. Endotoxin concentrations are determined with this system by the gelation of Limulus amebocyte lysate. The gelation time is computed by using an approximation to a polynomial equation from the resistance or the resonance frequency change. The gelation time measured was in good agreement with that obtained conventionally. The detection limit is 1 pg ml^?1. The maximum rate of change of the resistance was confirmed as a good index of endotoxin concentration in order to shorten the measurement time to ? 40 min. The changes in the resistance or resonance frequency were also considered as indices of endotoxin concentration.     

Tracer experiments for the determination of chemical forms of radioiodine in water samples

Two simple methods, (1) isotope exchange method and (2) anion exchanger column method, are developed for the determination of chemical forms of radioiodine (iodide and iodate) in water samples. Using these methods, transformations of chemical forms of iodine in various water samples were studied. It was observed that iodate in rain water (unfiltered) and milk tended to change iodide form, whereas iodide was converted to iodate form in seawater and tap water. After the Chernobyl accident both chemical forms of¹³¹I (iodide and iodate) were found in rain water samples collected in Japan.