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C. Hordequin D. Ristoiu L. Ranno J. Pierre 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,16(2):287-293
Magnetism and transport properties of the semi-Heusler compound NiMnSb are re-examined in great details. A wide set of experiments
(elastic and inelastic neutron scattering, static magnetic measurements, magnetoresistance, Hall effect, thermopower, FMR)
have been performed on polycrystals, single crystals or single-crystalline thin films, and the results are analysed. Special
emphasis is given to the magnetic excitations and to the relaxation mechanisms in this metallic ferromagnet. At low temperatures,
all experimental results hint at the existence of a fully spin-polarized conduction band (half metallic state). At higher
temperature (T > 80 K), but well below the Curie temperature (730 K), a cross-over to a usual metallic ferromagnetic state is evidenced
and discussed.
Received 10 January 2000 相似文献
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Trihalomethanes (THMs), chlorinated by-products in drinking water, have been determined by comparing some analytical methods, based on the following techniques: liquid-liquid extraction-gas chromatography-mass spectrometry (LLE-GC-MS), headspace-gas chromatography-mass spectrometry (headspace-GC-MS) and purge and trap-gas chromatography-mass spectrometry (PT-GC-MS). The mass spectrometer was operated in the SIM mode. The quantitative methods were validated and compared to the ability to identify and to measure reliably the yields of the toxic compounds. Good validation parameters were obtained for each method. 相似文献
3.
Ghizdavu L. Bălan C. David L. Bâtiu C. Cozar O. Ristoiu D. 《Journal of Thermal Analysis and Calorimetry》2000,62(3):729-736
New complexes CuL2×2H2O, CoL2×3H2O, MnL2×2H2O and FeL3×2H2O, L=γ-L -glutamyl-5-(p-nitroanilide), were synthesized and characterized by their spectral, magnetic and thermal properties. The thermal stabilities
of the synthesized complexes were examined in the temperature range 20–500°C. In all these complexes γ-L -glutamyl-5-(p -nitroanilide) acts as a bidentate ligand, its coordination involving the carbonyl oxygen and the nitrogen atom of the second
amino group. The local structure around the Cu(II) ion is pseudotetrahedral. In the Co(II), Mn(II) and Fe(III) complexes,
the metal ions are in the high-spin form, with octahedral stereochemistry.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
4.
Ocsana Opriş Maria-Loredana Soran Virginia Coman Florina Copaciu Dumitru Ristoiu 《Central European Journal of Chemistry》2013,11(8):1343-1351
This study is focused on the determination of some important antibiotics from different classes in waste water samples using solid phase extraction followed by high performance liquid chromatography with two detectors, diode array and mass spectrometer in positive ionisation mode. The investigated antibiotics include three penicillins (amoxicillin, ampicillin, penicillin G), two cephalosporins (ceftazidime, ceftriaxone), and two tetracyclines (tetracycline, doxycycline). The studied antibiotics were extracted from waste water samples using hydrophilic-lipophilic balanced cartridges. The extraction of antibiotics from water matrices was tested at several pH values. The best recoveries were obtained at pH 3 and 7 respectively. Depending on the nature of antibiotic, the limits of detection and quantification were obtained in the range of 0.07–0.92 µg mL?1 and 0.21–2.77 µg mL?1 respectively. Influent and effluent waste water samples were collected from a Waste Water Treatment Plant from Romania in order to detect the studied antibiotics. The antibiotics detected in the influent waste water samples were ceftriaxone (334 µg L?1), tetracycline (146 µg L?1) and doxycycline (110 µg L?1). In effluent waste water samples no target antibiotics were detected. 相似文献
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A four-channel NP-424 type gamma analyzer coupled with a large NaI(Tl) scintillator was calibrated using a137Cs point source. The volume-samples were plexiglas cylindrical boxes (D=76mm, H=40mm) directly placed on the NaI(Tl) detector. Measurements for 64 indoor positions at full-662 keV-peak were made. Sample selfabsorbtion was determined considering a linear attenuation for gamma rays and measuring the absorption factor for maximum thickness of the volume sample (h0=40mm). The obtained results for two types of environmental samples (soil and milk-powder) are compared with the data acquired from other Romanian laboratories, in the frame of the Environmental Radioactivity Action (ERA) which standardized such types of measurements. The same samples were measured with a calibrated GeLi detector (INAN-Louvain la Neuve) and the results were in good agreement with our measurements. Using this NaI(Tl) calibrated spectrometer some radiocesium deposits (56 localities) from Transylvanian region were measured. The results show that a large deposit exists in the direction NE-SW in connection with the radioactive cloud passing. For Alba region were measured more than 40 kBq/m2 of cesium deposit. 相似文献
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