Confined one-way mode at magnetic domain wall for broadband high-efficiency one-way waveguide, splitter and bender

We find the one-way mode can be well-confined at the magnetic domain wall by the photonic bandgap of gyromagnetic bulk material. Utilizing the well-confined one-way mode at the domain wall, we demonstrate the photonic one-way waveguide, splitter and bender can be realized with simple structures, which are predicted to be high-efficiency, broadband, frequency-independent, reflection-free, crosstalk-proof and robustness against disorder. Additionally, we find that the splitter and bender in our proposal can be transformed into each other with magnetic control, which may have great potential applications in all photonic integrated circuit.Comment: Appl. Phys. Lett. 100, 041108 (2012); (4 pages

An optimized analytical method for the simultaneous detection of iodoform, iodoacetic acid, and other trihalomethanes and haloacetic acids in drinking water

An optimized method is presented using liquid-liquid extraction and derivatization for the extraction of iodoacetic acid (IAA) and other haloacetic acids (HAA9) and direct extraction of iodoform (IF) and other trihalomethanes (THM4) from drinking water, followed by detection by gas chromatography with electron capture detection (GC-ECD). A Doehlert experimental design was performed to determine the optimum conditions for the five most significant factors in the derivatization step: namely, the volume and concentration of acidic methanol (optimized values  = 15%, 1 mL), the volume and concentration of Na2SO4 solution (129 g/L, 8.5 mL), and the volume of saturated NaHCO3 solution (1 mL). Also, derivatization time and temperature were optimized by a two-variable Doehlert design, resulting in the following optimized parameters: an extraction time of 11 minutes for IF and THM4 and 14 minutes for IAA and HAA9; mass of anhydrous Na2SO4 of 4 g for IF and THM4 and 16 g for IAA and HAA9; derivatization time of 160 min and temperature at 40°C. Under optimal conditions, the optimized procedure achieves excellent linearity (R2 ranges 0.9990–0.9998), low detection limits (0.0008–0.2 µg/L), low quantification limits (0.008–0.4 µg/L), and good recovery (86.6%–106.3%). Intra- and inter-day precision were less than 8.9% and 8.8%, respectively. The method was validated by applying it to the analysis of raw, flocculated, settled, and finished waters collected from a water treatment plant in China

Magnetism and Magnetic Isomers in Free Chromium Clusters

We have used the Stern-Gerlach deflection technique to study magnetism in chromium clusters of 20-133 atoms. Between 60 K and 100 K, we observe that these clusters have large magnetic moments and respond superparamagnetically to applied magnetic fields. Using superparamagnetic theory, we have determined the moment per atom for each cluster size and find that it often far exceeds the moment per atom present anywhere in the bulk antiferromagnetic lattice. Remarkably, our cluster beam contains two magnetically distinguishable forms of each cluster size with >= 34 atoms. We attribute this observation to structural isomers

Calibration of YSZ Sensors for the Measurement of Oxygen Concentration in Liquid Pb-Bi Eutectic

Although liquid lead-bismuth eutectic (LBE) is a good candidate for coolant in the subcritical transmutation blanket, it is known to be corrosive to stainless steel, the material of the carrying tubes and containers. Such longterm corrosion problem can be prevented by producing and maintaining a protective oxide layer on the exposed surface of stainless steel. For this purpose, it is required to accurately control the concentration of oxygen dissolved in LBE. Currently, YSZ (Yttria Stabilized Zirconia) oxygen sensors, based on an existing automotive oxygen sensor, with molten bismuth saturated with oxygen as the reference, have been selected for oxygen-concentration measurement. The oxygen concentration difference across the solid electrolyte and the resultant oxygen ion conduction inside the electrolyte establishes an electromagnetic force that is used to measure the ppb level concentration of oxygen dissolved in liquid LBE. A set of calibration curves of voltage vs. temperature ranging from 300 0C to 500 0C under various oxygen concentrations in liquid LBE for the YSZ oxygen sensor has been obtained and is presented in this paper. Although the current calibration strategy using the direct injection of hydrogen and oxygen is still inadequate to determine the oxygen concentration in the system, we have found a good candidate for our purpose, which is varying hydrogen to water steam ratio in the system

Magnetic structure of free cobalt clusters studied with Stern-Gerlach deflection experiments

We have studied the magnetic properties of free cobalt clusters in two semi-independent Stern-Gerlach deflection experiments at temperatures between 60 and 307 K. We find that clusters consisting of 13 to 200 cobalt atoms exhibit behavior that is entirely consistent with superparamagnetism, though complicated by finite-system fluctuations in cluster temperature. By fitting the data to the Langevin function, we report magnetic moments per atom for each cobalt cluster size and compare the results of our two measurements and all those performed previously. In addition to a gradual decrease in moment per atom with increasing size, there are oscillations that appear to be caused by geometrical shell structure. We discuss our observations in light of the two competing models for Langevin-like magnetization behavior in free clusters, superparamagnetism and adiabatic magnetization, and conclude that the evidence strongly supports the superparamagnetic model

Scaling and memory in the return intervals of energy dissipation rate in three-dimensional fully developed turbulence

We study the statistical properties of return intervals $r$ between successive energy dissipation rates above a certain threshold $Q$ in three-dimensional fully developed turbulence. We find that the distribution function $P_Q(r)$ scales with the mean return interval $R_Q$ as $P_Q(r)=R_Q^{-1}f(r/R_Q)$ except for $r=1$, where the scaling function $f(x)$ has two power-law regimes. The return intervals are short-term and long-term correlated and possess multifractal nature. The Hurst index of the return intervals decays exponentially against $R_Q$, predicting that rare extreme events with $R_Q\to\infty$ are also long-term correlated with the Hurst index $H_\infty=0.639$.Comment: 5 pages, 5 figure

The Equation of State and Quark Number Susceptibility in Hard-Dense-Loop Approximation

Based on the method proposed in [ H. S. Zong, W. M. Sun, Phys. Rev. \textbf{D 78}, 054001 (2008)], we calculate the equation of state (EOS) of QCD at zero temperature and finite quark chemical potential under the hard-dense-loop (HDL) approximation. A comparison between the EOS under HDL approximation and the cold, perturbative EOS of QCD proposed by Fraga, Pisarski and Schaffner-Bielich is made. It is found that the pressure under HDL approximation is generally smaller than the perturbative result. In addition, we also calculate the quark number susceptibility (QNS) at finite temperature and finite chemical potential under hard-thermal/dense-loop (HTL/HDL) approximation and compare our results with the corresponding ones in the previous literature.Comment: 12 pages, 3 figure