44 research outputs found

    New bridge circuit-type detector to measure precise resistance change of strain gauge at low temperature and magnetic field

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    We report a new highly accurate and versatile bridge-circuit-type detector that has a simple structure and demonstrates a low degree of error for measurements of thermal expansion and magnetostriction by the strain gauge method. As an example, a commercial physical property measurement system (PPMS) is combined with a compact bridge-circuit box. Thermal expansion and magnetostriction are calculated from the resistance of the bridge and bridge voltage, measured by the operation of a standard PPMS resistivity option. The performance of the new detector is demonstrated by measuring the temperature and magnetic field dependences of the strain to obtain the thermal expansion coefficient and magnetostriction of the single crystals of rare-earth compounds RAl2 (R = Dy, Tb). © 2016 The Japan Society of Applied Physics

    Crystal Structure of the Caged Magnetic Compound DyFe2Zn20 at Low Temperature Magnetic Ordering State

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    We have carried out X-ray powder diffraction and thermal expansion measurements of the caged magnetic compound DyFe2Zn20. Even though a strong magnetic anisotropy exists in the magnetization and magnetic susceptibility due to strong exchange interaction between Fe and Dy, almost all X-ray powder diffraction peaks at 14 K correspond to Bragg reflections of the cubic structural models not only at room temperature paramagnetic state but also at low temperature magnetic ordering state. Although the temperature change of the lattice constant is isotropic, an anomalous behavior was observed in the thermal expansion coefficient around 15 K, while the anomaly around TC = 53 K is not clear. The results indicate that the volume change is not caused by the ferromagnetic interaction between Fe and Dy but by the exchange interaction between two Dy ions. © 2015 The Authors. Published by Elsevier B.V

    Ecophysiological Role and Function of Uncultured Chloroflexi in an Anammox Reactor

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    The coexistence of uncultured heterotrophic bacteria belonging to the phylum Chloroflexi has often been observed in anaerobic ammonium oxidation (anammox) reactors fed with synthetic nutrient medium without organic carbon compounds. To determine if coexisting Chloroflexi in anammox reactors scavenge organic matter derived from anammox bacterial cells, the present study was conducted to investigate the substrate uptake pattern of the uncultured Chloroflexi present in an anammox reactor and to clarify if they take up microbial products derived from anammox bacterial cells. To accomplish this, combined microautoradiography and fluorescence in situ hybridization (MAR-FISH) was conducted. Phylogenetic analysis revealed that 36% of the clones analyzed in this study were affiliated with Chloroflexi. The sequence similarities to Anaerolinea thermophila and Caldilinea aerophila within the phylum Chloroflexi were only 81.0-88.7% and 80.3-83.8%, respectively. The uncultured Chloroflexi were found to incorporate sucrose, glucose, and N-acetyl-glucosamine. The 14C-tracing experiment revealed that the uncultured Chloroflexi were clearly MAR-positive, indicating the utilization of decaying anammox bacterial cell materials. Taken together, these results indicate that coexisting uncultured Chloroflexi in anammox reactors scavenge organic compounds derived from anammox bacterial cells.This research was partially supported by an Assistance for Research and Development of Construction Technology grant from the Ministry of Land, Infrastructure, Transport and Tourism, and by a Grant-in-Aid for Young Scientists (B) from the Ministry of Education, Culture, Sports, Science and Technology

    Discovery of antiferromagnetic chiral helical ordered state in trigonal GdNi3_3Ga9_9

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    We have performed magnetic susceptibility, magnetization, and specific heat measurements on a chiral magnet GdNi3_3Ga9_9, belonging to the trigonal space group R32R32 (\#155). A magnetic phase transition takes place at TNT_{\rm N} = 19.5 K. By applying a magnetic field along the aa axis at 2 K, the magnetization curve exhibits two jumps at ∼\sim 3 kOe and = 45 kOe. To determine the magnetic structure, we performed a resonant X-ray diffraction experiment by utilizing a circularly polarized beam. It is shown that a long-period antiferromagnetic (AFM) helical order is realized at zero field. The Gd spins in the honeycomb layer are coupled in an antiferromagnetic manner in the cc plane and rotate with a propagation vector qq = (0, 0, 1.485). The period of the helix is 66.7 unit cells (∼180\sim 180~nm). In magnetic fields above 3~kOe applied perpendicular to the helical cc axis, the AFM helical order changes to an AFM order with qq = (0, 0, 1.5).Comment: 7 pages, 12 figure

    Support for UNRWA's survival

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    The United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) provides life-saving humanitarian aid for 5·4 million Palestine refugees now entering their eighth decade of statelessness and conflict. About a third of Palestine refugees still live in 58 recognised camps. UNRWA operates 702 schools and 144 health centres, some of which are affected by the ongoing humanitarian disasters in Syria and the Gaza Strip. It has dramatically reduced the prevalence of infectious diseases, mortality, and illiteracy. Its social services include rebuilding infrastructure and homes that have been destroyed by conflict and providing cash assistance and micro-finance loans for Palestinians whose rights are curtailed and who are denied the right of return to their homeland

    Hitomi X-Ray Studies of Giant Radio Pulses from the Crab Pulsar

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    To search for giant X-ray pulses correlated with the giant radio pulses (GRPs) from the Crab pulsar, we performed a simultaneous observation of the Crab pulsar with the X-ray satellite Hitomi in the 2300 keV band and the Kashima NICT radio telescope in the 1.41.7 GHz band with a net exposure of about 2 ks on 2016 March 25, just before the loss of the Hitomi mission. The timing performance of the Hitomi instruments was confirmed to meet the timing requirement and about 1000 and 100 GRPs were simultaneously observed at the main pulse and inter-pulse phases, respectively, and we found no apparent correlation between the giant radio pulses and the X-ray emission in either the main pulse or inter-pulse phase. All variations are within the 2 fluctuations of the X-ray fluxes at the pulse peaks, and the 3 upper limits of variations of main pulse or inter-pulse GRPs are 22% or 80% of the peak flux in a 0.20 phase width, respectively, in the 2300 keV band. The values for main pulse or inter-pulse GRPs become 25% or 110%, respectively, when the phase width is restricted to the 0.03 phase. Among the upper limits from the Hitomi satellite, those in the 4.510 keV and 70300 keV bands are obtained for the first time, and those in other bands are consistent with previous reports. Numerically, the upper limits of the main pulse and inter-pulse GRPs in the 0.20 phase width are about (2.4 and 9.3) 10(exp 11) erg cm(exp 2), respectively. No significant variability in pulse profiles implies that the GRPs originated from a local place within the magnetosphere. Although the number of photon-emitting particles should temporarily increase to account for the brightening of the radio emission, the results do not statistically rule out variations correlated with the GRPs, because the possible X-ray enhancement may appear due to a >0.02% brightening of the pulse-peak flux under such conditions
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