Large magnetoresistance anomalies in Dy7Rh3

The compound Dy7Rh3 ordering antiferromagnetically below (TN=) 59 K has been known to exhibit a temperature (T) dependent electrical resistivity (rho) behavior in the paramagnetic state unusual for intermetallic compounds in the sense that there is a broad peak in rho(T) in the paramagnetic state (around 130 K) as though there is a semi-conductor to metal transition. In addition, there is an upturn below T_N due to magnetic super-zone gap effects. Here we report the influence of external magnetic field (H) on the rho(T) behavior of this compound below 300 K. The rise of rho(T) found below TN could be suppressed at very high fields (>> 60 kOe), thus resulting in a very large magnetoresistance (MR) in the magnetically ordered state. The most notable finding is that the magnitude of MR is large for moderate applications of H (say 80 kOe) in a temperature range far above T_N as well, which is untypical of intermetallic compounds. Thus, this compound is characterized by large MR anomalies in the entire T range of investigation.Comment: IOP Selec

Analysis Of The Permeability Spectra Of Spinel Ferrite Composites Using Mixing Rules

Magnetic permeability spectra of composite materials containing spinel ferrites (Ni-Zn or Mn-Zn types) have been studied using a permeability dispersion formula by the numerical analysis. The variation of d.c. permeability and the frequency dispersion parameters due to domain wall and gyromagnetic spin resonances with particle content were evaluated using two mixing rules, Coherent Model Approximation (CMA) and Maxwell-Garnet Approximation (MGA) assuming the isotropic particle shape. The variation of d.c. permeability with particle content for spinel ferrite composite can be predicted by the CMA and MGA using the permeability value of embedded ferrite. The dc susceptibility and resonance frequency of domain wall and spin components estimated by the numerical analysis can also be qualitatively described by the CMA and MGA. The type of frequency dispersion, relaxation or resonance, for domain wall and spin components can be analyzed by the estimated damping factors. © 2013 IEEE

Electromagnetic Properties Of Metal Granular Composite Materials For EMC Applications

Electromagnetic properties of copper and Fe55Ni45alloy (Permalloy) composite materials have been studied by measuring the relative complex permeability (µr = µr’– jµr”), and permittivity (Σr = Σr’– jΣr”) spectra over the microwave range, as well as the a.c. electrical conductivity σac spectra. The variation of σac and Σr with particle content shows the insulator-metal transition due to the percolation effect. The effective cluster model can be applied to the percolation effect in permittivity. The permeability spectra in Permalloy composites, which contain the percolated particles, can be affected by the eddy current effect. The permeability relaxation frequency of Permalloy composites shifts to the higher frequencies by the oxidation of embedded particle surfaces. © 2012 IEEE

Multiphase magnetic deflagrations in a Nd5Ge3 single crystal

We report magnetic deflagration phenomena ocurring in both antiferromagnetic and ferromagnetic phases in a single crystal of the intermetallic compound Nd5Ge3. We have investigated, using a trigger heat pulse, the spatial and time-resolved evolution of induced magnetic avalanches as a function of the applied magnetic field. The experimental data fit well with the theory of magnetic deflagration

High Frequency Permeability Of Fe-Al-Si Granular Composite Materials

High-frequency electromagnetic properties of Fe-Al-Si alloy (Sendust) granular composite materials have been studied by measuring their relative complex permeability (μr = μr’ – jμr”) and permittivity (εr = εr’ – j εr”) spectra. The bulk Fe-Al-Si alloy shows metallic electrical conduction, and permeability decreases rapidly with frequency. On the other hand, Sendust powder shows relatively high electrical resistivity. Sendust composite material demonstrates insulating electrical properties up to at least 80 vol.% particle content. Thus the relatively high permeability in the microwave frequency range can be obtained. Frequency dispersion characteristics of permeability for the composite were analyzed by the superposition of domain wall and gyromagnetic spin resonance formula. The particle content variation of permeability can be qualitatively described by a coherent model mixing rule. © 2011 IEEE

Development of an energy and environmental education program dealing with social issues

In the 3rd grader of junior high school, we propose a new subject "resources and energy" dealing with social issues. Through this subject, we aim to foster the ability to think from a multifaceted and integrated viewpoint. We conducted a questionnaire survey whether students understand about scientific or social terms related to energy in the next year. The degree of understanding of the students who learned the program was high. And there were many students who thought that social issues could be solved by science and technology in future in comparison with groups that did not study this program

Attenuation in Extended Structures Coated with Thin Magneto-Dielectric Absorber Layer

Thin absorbing layers containing magnetic alloy or ferrite inclusions can be effectively used for attenuating common-mode currents on extended structures, such as power cords, cables, or edge-coupled microstrip lines. An analytical model to evaluate attenuation on the coaxial line with the central conductor coated with a magneto-dielectric layer is proposed and validated by the experiments and numerical modeling. The analytical model is validated using available magneto-dielectric samples of different thicknesses. This model can serve for comparing and predicting the absorptive properties of different samples of magneto-dielectric materials, whose compositions may be unknown, but dielectric and magnetic properties can be determined by independent measurements over the specified frequency ranges. From modeling the absorption in a coaxial line with a wrapped central conductor, it could be concluded whether it is reasonable to use this particular material in such applications as a shield on an Ethernet or other cable, for reducing potential common-mode currents and unwanted radiation in the frequency range of interest

Development and evaluation of automated ultrasonographic detection of bladder diameter for estimation of bladder urine volume

Bladder urine volume has been estimated using an ellipsoid method based on triaxial measurements of the bladder extrapolated from two-dimensional ultrasound images. This study aimed to automate this process and to determine the accuracy of the automated estimation method for normal and small amounts of urine. A training set of 81 pairs of transverse and longitudinal ultrasound images were collected from healthy volunteers on a tablet-type ultrasound device, and an automatic detection tool was developed using them. The tool was evaluated using paired transverse/longitudinal ultrasound images from 27 other healthy volunteers. After imaging, the participants voided and their urine volume was measured. For determining accuracy, regression coefficients were calculated between estimated bladder volume and urine volume. Further, sensitivity and specificity for 50 and 100 ml bladder volume thresholds were evaluated. Data from 50 procedures were included. The regression coefficient was very similar between the automatic estimation (β = 0.99, R2 = 0.96) and manual estimation (β = 1.05, R2 = 0.97) methods. The sensitivity and specificity of the automatic estimation method were 88.5% and 100.0%, respectively, for 100 ml and were 94.1% and 100.0%, respectively, for 50 ml. The newly-developed automated tool accurately and reliably estimated bladder volume at two different volume thresholds of approximately 50 ml and 100 ml

Comparative Toxicity of Tapentadol and Tramadol Utilizing Data Reported to the National Poison Data System

BackgroundTapentadol (TAP) and tramadol (TRA) provide pain relief through similar monoaminergic and opioid agonist properties.ObjectiveTo compare clinical effects and medical outcomes between TAP and TRA exposures reported to the National Poison Data System of the American Association of Poison Control Centers.MethodsA retrospective cohort study was conducted analyzing national data for single medication TAP or TRA cases reported from June 2009 through December 2011. Case outcomes, dichotomized as severe versus mild; clinical effects; and use of naloxone were compared.ResultsThere were 217 TAP and 8566 TRA cases. Significantly more severe outcomes were associated with TAP exposures for an all-age comparison (relative risk [RR] = 1.24; 95% CI = 1.04-1.48), and for the <6-year-old age group (RR = 5.76; 95% CI = 2.20-15.11). Patients with TAP exposures had significantly greater risk of respiratory depression (RR = 5.56; 95% CI = 3.50-8.81), coma (RR = 4.16; 95% CI = 2.33-7.42), drowsiness/lethargy (RR = 1.38; 95% CI = 1.15-1.66), slurred speech (RR = 3.51; 95% CI = 1.98-6.23), hallucination/delusion (RR = 7.25; 95% CI = 3.61-14.57), confusion (RR = 2.54; 95% CI = 1.56-4.13) and use of naloxone (RR = 3.80; 95% CI = 2.96-4.88). TRA exposures had significantly greater risk of seizures (RR = 7.94; 95% CI = 2.99-20.91) and vomiting (RR = 1.96; 95% CI = 1.07-3.60).ConclusionTAP was associated with significantly more toxic clinical effects and severe outcomes consistent with an opioid agonist. TRA was associated with significantly higher rates of seizures and vomiting