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Scanning electron microscope-cathodoluminescence (SEM-CL) analysis was performed for neodymium–iron–boron (NdFeB) and samarium–cobalt (Sm–Co) magnets to analyze the rare-earth elements present in the magnets. We examined the advantages of SEM-CL analysis over conventional analytical methods such as SEM-energy-dispersive X-ray (EDX) spectroscopy and SEM-wavelength-dispersive X-ray (WDX) spectroscopy for elemental analysis of rare-earth elements in NdFeB magnets. Luminescence spectra of chloride compounds of elements in the magnets were measured by the SEM-CL method. Chloride compounds were obtained by the dropwise addition of hydrochloric acid on the magnets followed by drying in vacuum. Neodymium, praseodymium, terbium, and dysprosium were separately detected in the NdFeB magnets, and samarium was detected in the Sm–Co magnet by the SEM-CL method. In contrast, it was difficult to distinguish terbium and dysprosium in the NdFeB magnet with a dysprosium concentration of 1.05 wt% by conventional SEM-EDX analysis. Terbium with a concentration of 0.02 wt% in an NdFeB magnet was detected by SEM-CL analysis, but not by conventional SEM-WDX analysis. SEM-CL analysis is advantageous over conventional SEM-EDX and SEM-WDX analyses for detecting trace rare-earth elements in NdFeB magnets, particularly dysprosium and terbium.
An X-ray diffractometer (XRD) was modified to a low-power total reflection X-ray fluorescence (TXRF) spectrometer. This was realized by reducing the XRD tube power (3 kW) down to 10 W by a Spellman power supply. The present spectrometer consisted of a waveguide slit, Si-PIN detector, a goniometer and two Z-axis stages that were set on a diffractometer guide rail. This unit was easy in assembly. The first measurements with this spectrometer were presented. The minimum detection limit for Cr was estimated to be a few nanograms or at the level of 1013 atoms cm−2.
Titan, the largest satellite of Saturn, has a thick atmosphere containing nitrogen and methane. A variety of organic compounds have been detected in the atmosphere, most likely produced when atmospheric gases are exposed to ultraviolet light, electrons captured by the magnetosphere of Saturn and cosmic rays. The Cassini/Huygens probe showed that the average temperature on the surface of Titan is 93.7 K, with lakes of liquid ethane and methane. Sub-surface mixtures of liquid ammonia and water may also be present. We have synthesized complex organic compounds (tholins) by exposing a mixture of nitrogen and methane to plasma discharges, and investigated their interactions with several different liquids that simulate Titan's liquidosphere. We found that coacervates formed when tholins were extracted in non-polar solvents followed by exposure to aqueous ammonia solutions. The results suggest that coacervates can self-assemble in Titan's liquidosphere which have the potential to undergo further chemical evolution. Similar processes are likely to occur in the early evolution of habitable planets when tholin-like compounds undergo phase separation into microscopic structures dispersed in a suitable aqueous environment.
Brown adipose tissue (BAT) is responsible for cold- and diet-induced thermogenesis, and thereby contributes to the control of whole-body energy expenditure (EE) and body fat content. BAT activity can be assessed by fluoro-2-deoxyglucose (FDG)-positron emission tomography (PET) in human subjects. Grains of paradise (GP, Aframomum melegueta), a species of the ginger family, contain pungent, aromatic ketones such as 6-paradol, 6-gingerol and 6-shogaol. An alcohol extract of GP seeds and 6-paradol are known to activate BAT thermogenesis in small rodents. The present study aimed to examine the effects of the GP extract on whole-body EE and to analyse its relation to BAT activity in men. A total of nineteen healthy male volunteers aged 20–32 years underwent FDG-PET after 2 h of exposure to cold at 19°C with light clothing. A total of twelve subjects showed marked FDG uptake into the adipose tissue of the supraclavicular and paraspinal regions (BAT positive). The remaining seven showed no detectable uptake (BAT negative). Within 4 weeks after the FDG-PET examination, whole-body EE was measured at 27°C before and after oral ingestion of GP extract (40 mg) in a single-blind, randomised, placebo-controlled, crossover design. The resting EE of the BAT-positive group did not differ from that of the BAT-negative group. After GP extract ingestion, the EE of the BAT-positive group increased within 2 h to a significantly greater (P< 0·01) level than that of the BAT-negative group. Placebo ingestion produced no significant change in EE. These results suggest that oral ingestion of GP extract increases whole-body EE through the activation of BAT in human subjects.
The possibility of scanning electron microscope (SEM) observation and energy dispersive X-ray (EDX) spectrometry analysis in microscale regions of insulating samples using diluted ionic liquid was investigated. It is possible to obtain clear secondary electron images of insulating samples such as a rock and mineral at 5,000 times magnification by dropping 10 μL of 1 wt% of 1-ethyl-3-methylimidazolium acetate (EMI-CH3COO) diluted with ethanol onto the samples. We also obtained EDX spectra of the samples in microscale regions (∼5 μm2) without overlapping EDX spectra of other minerals with different composition. It might be possible to perform quantitative analysis of the samples if a method that does not need standard samples is applied or an X-ray detector sensitive for light elements was attached. The method of dropping 1 wt% EMI-CH3COO diluted with ethanol onto insulating samples is useful for SEM observation, EDX analysis in microscale regions, and the preservation of scarce rock and mineral samples because ionic liquid can be easily removed with acetone.
We report the Suzaku follow-up observations of the Gamma-ray pulsars, 1FGL J0614,13328, J1044.55737, J1741.82101, and J1813.31246, which were discovered by the Fermi Gamma-ray observatory. Analysing Suzaku/XIS data, we detected X-ray counterparts of these pulsars in the Fermi error circle and interpreted their spectra with absorbed power-law functions. These results indicate that the origin of these X-ray sources is non-thermal emission from the pulsars or from Pulsar Wind Nebulae (PWNe) surrounding them. Moreover we found that J1741.82101 exhibits a peculiar profile: spin-down luminosity vs flux ratio between X- and gamma-rays is unusually large compared to usual radio pulsars.
Hard X-ray polarization is believed to be one of the most promising methods to investigate the physical processes just around the central engines by constraining the magnetic environment. For this purpose we are now developing a compact and highly sensitive hard X-ray polarimeter aboard a university class micro-satellite “TSUBAME”. We are now developing the flight model of the satellite aiming for the launch in late 2012 from Russia.
A specimen containing nanograms of sulfur, calcium, and 3d transition metal elements was measured by incident X-ray beams of various sizes restricted by a waveguide placed in a portable TXRF spectrometer. The signal to background ratios of spectra decreased with an increase in incident X-ray beam size. The portable spectrometer was also applied to rainwater and a specimen containing antimony and rare earth elements. Nanograms of elements in these specimens were detected by K-line or L-line excitation.
We propose a simple and practical solution to remove artificial contrast inhibiting direct interpretation of atomic arrangements in aberration-corrected TEM. The method is based on a combination of “image subtraction” for elimination of nonlinear components in images and newly improved “image deconvolution” for proper compensation of nonflat phase contrast transfer function. The efficiency of the method is shown by experimental and simulation data of typical materials such as gold, silicon, and magnesium oxide. The hypothetical results from further improvements of TEM instruments are also simulated. It is concluded that we can approach actual atomic structures by using the present method, that is, a proper combination of a Cs corrector, image subtraction, and image deconvolution processes.
The characteristic of the electrostatic mode excited in non-neutral plasma in the equilibrium state is closely related to the internal state of plasma. This relationship has been used for non-destructive diagnosis of non-neutral plasma. Under the present conditions, this diagnosis is only supported by simplified theory. We employ numerical simulation reflecting actual experimental conditions and examine the characteristic of this electrostatic mode.
We have fabricated a new ferroelectric memory FET, which consists of the Au/Pb(Zr0.52Ti0.48)O3/SiO2/Si gate structure. Ferroelectric PZT thin film with a thickness of 250~400 nm was prepared by using Excimer Laser Ablation Deposition. Silicon oxide successfully served as a buffer layer between ferroelectric and Si substrate to suppress the charge injection and prevent Pb interdiffusion. Electrical properties of the ferroelectric FET have been characterized through both the Capacitance vs. Voltage(C-V) and Current vs. Voltage(I-V) measurements, showing a typical memory characteristics of FET devices, i.e., the ON state and OFF state were nonvolatile for about thirty minutes and several hours, respectively.
Oxygen K-V (Kα) X-ray fluorescence spectra of MgO, Cu2O, CuO, La2CuO4, La2-xSrxCuO4, YBa2Cu3O7-x , and GdBa2Cu3O7-x are measured. The local (oxygen) and partial (2p) electron density of states (DOS) of these compounds are calculated by the cluster approximation with the discrete variational (DV) Hartree-Fock-Slater (Xα) method. The calculated O 2p DOS are compared with the measured X-ray fluorescence spectra. It is found that the measured 0 K-V X-ray fluorescence line shapes are well reproduced by the O 2p DOS calculated by a cluster including the second nearest neighbor atoms (oxygen atoms) in the solids. This indicates that the oxygen K-V X-ray emission spectra reflect the oxygen-oxygen orbital hybridization in the solid as well as the oxygen-metal orbital hybridization.
Profile changes of copper Lα (L3-V) and Lβ (L2-V) X-ray fluorescence spectra are interpreted. It is shown that the intensity of the high energy shoulder of the Cu L X-ray spectra has a relation to the intensity of the so-called ‘shake-up’ satellite in 2p X-ray photoelectron spectra; the high energy shoulder of the divalent copper La is weak for covalent compounds and strong for ionic compounds. It is also shown that the Lβ/Lα intensity ratio changes with the change of copper concentration of the analyte as well as the change of chemical state of the analyte.
This paper deals with soft X-ray spectra of compounds which have one or more spectator hole(s) in the valence orbitals. The aim is to give a simple picture of the complicated chemical effects and to describe implications of the chemical effects to know the chemical state from the complicated spectra of materials. The first example of the system which has a spectator hole in the valence orbital is the intensity modifications of the shake-off satellites (KM-→LM) in chlorine Kα spectra. The second example of the system which has spectator holes in the valence orbitals is the multiplet structure of Lα spectra of the transition-metal compounds. It is described that the chemical effects of these two systems are clearly interpreted by the avoided crossing  of the molecular orbitals, one of which has a localized hole. We also describe the systems which have no spectator holes. The interpretation of the X-ray spectra of these systems are easy by a molecular-orbital calculation at the ground state.
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