6,312 research outputs found

    Incommensurate-Commensurate Magnetic Phase Transition in SmRu2_{2}Al10_{10}

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    Magnetic properties of single crystalline SmRu2_{2}Al10_{10} have been investigated by electrical resistivity, magnetic susceptibility, and specific heat. We have confirmed the successive magnetic phase transitions at TN=12.3T_{\text{N}}=12.3 K and TM=5.6T_{\text{M}}=5.6 K. Resonant x-ray diffraction has also been performed to study the magnetic structures. Below TNT_{\text{N}}, the Sm3+^{3+} moments order in an incommensurate structure with q1=(0,0.759,0)q_1=(0, 0.759, 0). The magnetic moments are oriented along the orthorhombic bb axis, which coincides with the magnetization easy axis in the paramagnetic phase. A very weak third harmonic peak is also observed at q3=(0,0.278,0)q_3=(0, 0.278, 0). The transition at TMT_{\text{M}} is a lock-in transition to the commensurate structure described by q1=(0,0.75,0)q_1=(0, 0.75, 0). A well developed third harmonic peak is observed at q3=(0,0.25,0)q_3=(0, 0.25, 0). From the discussion of the magnetic structure, we propose that the long-range RKKY interaction plays an important role, in addition to the strong nearest neighbor antiferromagnetic interaction.Comment: 11 pages, 12 figures, accepted in PR

    Kondo effect in CeXc_{c} (Xc_{c}=S, Se, Te) studied by electrical resistivity under high pressure

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    We have measured the electrical resistivity of cerium monochalcogenices, CeS, CeSe, and CeTe, under high pressures up to 8 GPa. Pressure dependences of the antiferromagnetic ordering temperature TNT_{N}, crystal field splitting, and the lnT\ln T anomaly of the Kondo effect have been studied to cover the whole region from the magnetic ordering regime at low pressure to the Fermi liquid regime at high pressure. TNT_{N} initially increases with increasing pressure, and starts to decrease at high pressure as expected from the Doniach's diagram. Simultaneously, the lnT\ln T behavior in the resistivity is enhanced, indicating the enhancement of the Kondo effect by pressure. It is also characteristic in CeXc_{c} that the crystal field splitting rapidly decreases at a common rate of 12.2-12.2 K/GPa. This leads to the increase in the degeneracy of the ff state and further enhancement of the Kondo effect. It is shown that the pressure dependent degeneracy of the ff state is a key factor to understand the pressure dependence of TNT_{N}, Kondo effect, magnetoresistance, and the peak structure in the temperature dependence of resistivity.Comment: 9 pages, 5 figures, accepted for publication in J. Phys. Soc. Jp

    A Nuclear Physics Program at the ATLAS Experiment at the CERN Large Hadron Collider

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    The ATLAS collaboration has significant interest in the physics of ultra-relativistic heavy ion collisions. We submitted a Letter of Intent to the United States Department of Energy in March 2002. The following document is a slightly modified version of that LOI. More details are available at: http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/SM/ionsComment: Letter of Intent submitted to the United States Department of Energy Nuclear Physics Division in March 2002 (revised version

    Metacarpophalangeal pattern profile analysis of a sample drawn from a North Wales population

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    This is tha author's PDF version of an article published in Annals of human biology© 2001. The definitive version is available at http://www.tandf.co.uk/journalsSexual dimorphism and population differences were investigated using metacarpophalangeal pattern profile (MCPP) analysis. Although it is an anthropmetric technique, MCPP analysis is more frequently used in genetic syndrome analysis and has been under-used in the study of human groups. The present analysis used a series of hand radiographics from Gwynedd, North Wales, to make comparisons, first, between the sexes within the sample and then with previously reported data from Japan. The Welsh sexes showed MCPP analyses that indicated size and shape differences but certain similarities in shape were also evident. Differences with the Japanese data were more marked. MCPP anlysis is a potentially useful anthropmetric technique but requires further statistical development

    Preparation of high performance conductive Polyaniline Magnetite (PANI/Fe3O4) nanocomposites by sol-gel method

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    The conductivities of polyaniline magnetite (PANI/Fe3O4) nanocomposites prepared by sol-gel method were measured by standard van der Pauw DC 4-point probe method. PANI/Fe3O4 conductivity was measured as a function of wt % (5, 10, 15, 20 and 25 wt %) of Fe3O4 nanoparticles. It was observed that the conductivity of polyaniline containing certain percentage of Fe3O4 nanoparticles is slightly lower than the bulk PANI nanotubes and drastically decreases with increase of wt % Fe3O4 nanoparticles. The high conductivities of PANI/ Fe3O4 nanocomposites was observed due to high concentration of dopant (oxidants) used in the polymerization process and the optimization of these composites allows this being use as a parameter for the production of nanofibers. Fourier transform infrared spectra, field emission scanning electron microscope, X-ray diffraction and ultraviolet-visible absorption spectra are used to characterize the phase structure, morphologies and functional group of the PANI/Fe3O4 composites samples. Fourier transform infrared analysis indicates the presence of PANI containing Fe3O4 nanoparticles and the field emission scanning electron microscope (FESEM) results has proven that the formation of nanofibers in the PANI/Fe3O4 nanocomposites. The crystalline phase of PANI/Fe3O4 nanocomposites studied by X-ray diffraction indicated that the Fe3O4 nanoparticles was present in the PANI matrices

    Local Susceptibility Against Soft Errors in Dynamic Random Access Memories (DRAMs) Analyzed by Nuclear Microprobes

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    A novel evaluation technique for soft errors in Mbit DRAMs (dynamic random access memories) has been developed using a 400 keV proton microprobe system. This technique, which is called soft error mapping, consists of a bit-state mapping image and a secondary electron mapping image, and can reveal the correlation between the incident position of protons and susceptibility against soft errors in DRAMs. Soft errors are found to be induced by proton incidence at 400 keV within about 6 μm around the memory cell in the case of DRAMs with a conventional well. The susceptible area against proton incidence is much larger than the memory cell size. It is found that the area within 4 μm around the memory cell is, in particular, highly sensitive to 400 keV protons. A threshold dose to radiation hardness is estimated by deterioration of the DRAMs during soft error mapping. A buried barrier layer, formed by high-energy ion-implantation, was found to control the charge collection of induced carriers and to suppress soft errors by 400 keV proton microprobes

    Investigation of Blood Parameters and Ovarian Morphology of Laying Hens Feeding Lavandula Stoechas Essence

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    The objective of this study was to evaluate the effects of different levels of Lavander stoechas essence on blood parameters and ovarian morphology of laying hens for 8 weeks. This experiment was conducted with 160 Hy-Line (W36) laying hens (30 wks of age) randomly divided into 4 experimental groups, 5 replicates and 8 birds per each (2 cages for each replicate and 4 birds in each cage). Treatments were control (without Lavander essence), and levels of 200, 400, and 600 ppm Lavander essence. All hens were provided the layer diets (2870 kcal/kg ME and 15.5 % CP) ad- libitum and received 16 h of light/ 8 h of dark. At the end of experiment, 2 birds of each replicate were randomly selected and blood samples were collected by brachial venipuncture. Serum was harvested by centrifugation and frozen for future analysis of plasma lipid. After that birds were killed by cervical dislocation for morphological assessments of ovaries. The weights of the oviduct, ovary, and stroma were recorded. The stroma weight comprised the ovarian tissue remaining after the large yellow follicles (LYF) were counted and removed. The number of small yellow follicles (SYF) and postovulatory follicles (POF) was recorded. Blood triglycerides, glucose and HDL were not affected by the treatments but by adding Lavender essence to the diet, cholesterol and LDL concentration decreased significantly in comparison with control diet (p<0.05). In addition, the levels of Lavander essence had no effect on the relative weight of the ovary, oviduct, stroma and number of SYF and POF. However, the levels of 200 and 400 ppm of Lavender caused significant increase of number and weight of LYF. The results showed that the addition of essence of Lavender up to 400 ppm increased weight and numbers of LYF

    Heavy Ion Physics at the LHC with the ATLAS Detector

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    The ATLAS detector at CERN will provide a high-resolution longitudinally-segmented calorimeter and precision tracking for the upcoming study of heavy ion collisions at the LHC (sqrt(s_NN)=5520 GeV). The calorimeter covers |eta|<5 with both electromagnetic and hadronic sections, while the inner detector spectrometer covers |eta|<2.5. ATLAS will study a full range of observables necessary to characterize the hot and dense matter formed at the LHC. Global measurements (particle multiplicities, collective flow) will provide access into its thermodynamic and hydrodynamic properties. Measuring complete jets out to 100's of GeV will allow detailed studies of energy loss and its effect on jets. Quarkonia will provide a handle on deconfinement mechanisms. ATLAS will also study the structure of the nucleon and nucleus using forward physics probes and ultraperipheral collisions, both enabled by segmented Zero Degree Calorimeters.Comment: 9 pages, 8 figures, submitted to the Proceedings of Quark Matter 2006, Shanghai, China, November 14-20, 200
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