295 resultados para anomalous Eu3 5D0->F-7(0) transition
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The reduction of RE3+ to RE2+ (RE=Eu, Sm and Tm) in SrB6O10 prepared in air by high-temperature solid state reaction was observed. The luminescent properties of Eu2+ and Tm2+ show f-d transition and Sm2+ shows f-f transition at room temperature. Three crystallographic sites for Sm2+ in matrix are available. Vibronic transition of D-5(0)-F-7(0) of Sm2+ was studied. The coupled phonon energy about 108 cm(-1), was determined: from the vibronic transition. Due to the thermal population from D-5(0) level, (D1-FJ)-D-5-F-7 (J=0, 1, 2) transitions of Sm2+ were observed at room temperature. A charge compensation mechanism is proposed as a possible explanation.
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Stable lipid film was made by casting lipid in chloroform onto a glassy carbon electrode. This model of a biological membrane was used to investigate the oxidation of dihydronicotinamide adenine dinucleotide (NADH) by dopamine. After this electrode had been immersed in dopamine solution for 10 h, it was found that some dopamine had been incorporated in the film. The cyclic voltammogram was obtained for the oxidation of 2.0 X 10(-3) mol 1(-1) NADH with dopamine incorporated in the films. All electrochemical experiments were performed in 0.005 mol 1(-1) phosphate buffer (pH 7.0) containing 0.1 mol 1(-1) NaCl without oxygen. The oxidation current increased gradually with successive sweeps and reached steady state. It was a different phenomenon from previous results. The anodic overpotential was reduced by about 130 mV compared with that obtained at a bare glassy carbon electrode. The diffusion coefficient for 2.0 X 10(-3) mol 1(-1) NADH was 6.7 X 10(-6) cm(2) s(-1). (C) 1999 Elsevier Science S.A. All rights reserved.
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To investigate the changes in the chemical weathering intensity of dust source region in Asia continent, ~(87)Sr/~(86)Sr ratios of acid-washed residues from the loess deposits in China and Tajikistan were analyzed, respectively. The results and conclusions are listed as below. 1. The oscillation of ~(87)Sr/~(86)Sr ratios of acid-insoluble residues in the Chinese Loess Plateau was mainly attributed to the chemical weathering intensity of the source region and the grain size. Counteracted the effect of particle size, the calibrated 87Sr/S6Sr ratio can be used as a proxy for the chemical weathering intensity of the source region. 2. The Sr/ Sr ratios of red clay-loess sequence from the Loess Plateau indicate that the chemical weathering intensity of the dust source region between 7.0 and 2.6 Ma is stronger than that in the Quaternary period. This also suggests a general decline in chemical weathering intensity of the source region from 2.6 Ma to the present. Such pattern is more remarkable since 1.0 Ma BP. 3. The ~(87)Sr/~(86)Sr ratios of the Tajik loess during 0.8-1.8 Ma is much more higher than those from 0.8 Ma to the present. This implies that the chemical weathering intensity of the source region in Central Asia is much stronger during 0.8-1.8 Ma than the period since 0.8 Ma. 4. The record of Sr isotope ratios from both sections shows an accelerating course of aridity of the Asian dust source region over the Quaternary period.
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The photodissociation of C6H5Br at 266 nm has been investigated on the universal crossed molecular beam machine, and time-of-flight spectra as well as the angular distribution of Br atom have been measured. Photofragment translational energy distribution P(E-t) reveals that about 47% of the available energy is partitioned into translational energy. The anisotropy parameter beta at this wavelength is -0.7+/-0.2. From P(E-t) and beta, we deduce that C6H5Br photodissociation is a fast process and the transition dipole moment is almost perpendicular to the C-Br bond. Ab initio calculations have been performed, and the calculated results show that the geometry of the first excited state of bromobenzene has changed apparently compared with that of the ground state. Two kinds of possible fast dissociation mechanism have also been proposed. (C) 1999 American Institute of Physics. [S0021-9606(99)01206-4].
Resumo:
0.05 mol/L Tris0.15 mol/L NaCl(VCR)-1.68 V(vs. Ag/AgCl)1.0*10^{-8}2.0*10^{-7}mol/L VCR7.0*l0^{-9} mol/LVCRFrumkinVCRVCR
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Thermally induced recovery of nanoindents in a CUAINi single crystal shape memory alloy was studied by nanoindentation in conjunction with a heating stage. Nanoindents formed by a Berkovich indenter at room temperature were heated to 40, 70 and 100 degrees C. Partial recovery was observed for the nanoindents. The recovery ratio depended on the heating temperature. Indentation of CuAlNi can induce inelastic deformation via dislocation motion and a stress-induced matensitic transformation. The percentages of dislocation-induced plastic strain would affect the thermal deformation of CuAlNi, because the induced dislocations could stabilize stress-induced martensite plates even when the temperature above austenite finish temperature, A(f). When the applied indentation load is low (less than 10,000 mu N), the shape recovery strain is predominant, compared with the dislocation-induced plastic strain. Therefore, the degree of indent recovery in the depth direction, delta(D), is high (about 0.7-0.8 at 100 degrees C).
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3,700-1100K,3.5-4.5MPa,0.6/1/2.5s:,,45%,,,,,0.5MJ/kg,JP-70.7MJ/kg(60%)
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S MESEMEMSMEMSCuAINiNITiNITi1AFM2AFM31CuAINiAf21000ONCuAINi100600.70.80.93CuAINiNITiNITi4CuAINi
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Catalytic cracking of China no. 3 aviation kerosene using a zeolite catalyst was investigated under supercritical conditions. A three-stage heating/cracking system was specially designed to be capable of heating 0.8 kg kerosene to a temperature of 1050 K and pressure of 7.0 MPa with maximum mass flow rate of 80 g/s. Sonic nozzles of different diameters were used to calibrate and monitor the mass flow rate of the cracked fuel mixture. With proper experiment arrangements, the mass flow rate per unit throat area of the cracked fuel mixture was found to well correlate with the extent of fuel conversion. The gaseous products obtained from fuel cracking under different conditions were also analyzed using gas chromatography. Composition analysis showed that the average molecular weight of the resulting gaseous products and the fuel mass conversion percentage were a strong function of the fuel temperature and were only slightly affected by the fuel pressure. The fuel conversion was also shown to depend on the fuel residence time in the reactor, as expected. Furthermore, the heat sink levels due to sensible heating and endothermic cracking were determined and compared at varying test conditions. It was found that at a fuel temperature of similar to 1050 K, the total heat sink reached similar to 3.4 MJ/kg, in which chemical heat sink accounted for similar to 1.5 MJ/kg.
Resumo:
Near infrared broadband emission characteristics of bismuth-doped aluminophosphate glass have been investigated. Broad infrared emissions peaking at 1210nm, 1173nm and 1300nm were observed when the glass was pumped by 405nm laser diode (LD), 514nm Ar+ laser and 808nm LD, respectively. The full widths at half maximum (FWHMs) are 235nm, 207nm and 300nm for the emissions at 1210nm, 1173nm and 1300nm, respectively. Based on the energy matching conditions, it is suggested that the infrared emission may be ascribed to P-3(1) --> P-3(0) transition of Bi+. The broadband infrared luminescent characteristics of the glasses indicate that they are promising for broadband optical fiber amplifiers and tunable lasers. (C) 2005 Optical Society of America.
Resumo:
The synthesis and optical properties of Y3Al5O12:Tb3+ phosphors are reported in this paper. Y3Al5O12:Tb3+ phosphors were synthesized by a facile solution combustion method. Citric acid traps the constituent cations and also acts as a fuel. Y3Al5O12 (YAG) phase can crystallize through sintering at 900 degrees C for 2 h, and there were no intermediate phases such as YAlO3 (YAP) and Y4Al2O9 (YAM) in the sintering process. The excitation spectra of crystalline Y3Al5O12:Tb3+ are different from that of amorphous one due to the crystal field effect. The emission spectra mainly show D-5(4) -> F-7(6) transition under UV excitation. The higher concentration quenching in Y3Al5O12:Tb3+ nanophosphors may be due to the confinement effect on resonant energy transfer of nanocrystalline. It is also indicated that the solution combustion synthesis method provides a good distribution of Tb3+ activators in Y3Al5O12 host. (c) 2005 Published by Elsevier B.V.
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OryzaPoaceae202(O. sativa LO. glaberrima Steud) 10()A, B, C, BC, CD, E, F, G, HJ HKA8AAAAAA;O. rufipogonO. nivara 1. A 4Adh1 3A81O. meridionalisA;2O. sativa ssp. japonica O. sativa ssp. indicajaponica indica;3O. rufipogonO. nivara;4O. barthiiO. glaberrimaO. longistaminataO. glaberrima/O. barthii.;5A22.0MYA0.7 0.4 MYAITSmatK 2. Oryza rufipogon O. nivara O. rufipogonO. nivara45-UTRWaxy, LHSCatA11O. rufipogonO. nivara4w0.0110.014;24shared polymorphism(fixed difference);3indicajaponicaO. rufipogon (O. nivara) 3 3O. rufipogonO. nivara371DNA;2O. rufipogonO. nivara230.013O. rufipogon46.1%O. nivara9.1%;33AO. meridionalis;3BC
Resumo:
(Agrobacterium rhizogenes)16011000150015834A4(Artemisia annua L.)pRi1601pRi15834pRiA4pRi1601pRi15834;;(Gtowth RatioGR)(Number of Side RootsNSR81601-L-1, 1601-L-2, 1601-L-3, 1601-L-4, 15834-L-1, 1601-P-I, 16 01-P-215834-L-2Southern160l-1-11801-L-2, 1601-L-31601-L-41601-P-11601-P-28QHS(16/8hrs)2516 01-L-11601-L-21601-L-31601-L-41601-P-l1601-P-216 01-L-3160l-L-1;1601-L-1QHS1. 048%1601-1-3QHS160Z-L-315834 -L-12583:1-L-2l000mLMS3000mL1601-L -315834-L-115834-L-2ll0rlpmHairy Root BalisHRBHRBQHsHpLCQHS MSQHS lKN0318.7910-3M1601- L-114. 8410-3MQHSNH-4N0-310.93-12. 49103M1601-L-10-20.6210-3MQHS20. 62lO-3MQHSNH-4+N0-3-0. 37-0. 4-0.52:10.52 - 0.58:1QHS 2H-2P0-4-2.49810-3M0-2. 498l0-3MH2P4 -0-1.249lO-3MQHS1.24910-3MQHS 316 01-L-1Ca-2+0.198- 0.76610-3M0-3.69510-3MCa-2+QHSCa-2+3.695l0-3M 4Mg-2+0. 14210-3M-7.506l0-3MHPLCUVQHSMg-2+QHS 5Fe-2+0. 25 -1010-3M16 01- L-1QHS 616 01- L-3KI2.5ppmKIQHS 7H2BO3l601-L-lHPLCQHSH3BO3100ppm400ppmQHS1.69mg/g1.80mg/g(DW) 8Cu-2+1601-L-31601-L-3Cu-2+1.00ppm0 -1.00ppmCu+QHSCu2+0.05ppmQHS 1601-L-l2535 1601-L-31601-L-1 (1) (2)530- 60glL50glL60g/L30gL (3)1560g/L3060-90g/L30-40g/L (4)51530g/L60g/L90g/L3060g/L90g/L (5)/ pHQHSpH5.O-6.51601-L-15.OpH5.81601-1-1QHSpH4.5-5.2. pH7.OpHl0.OpH(24- 48hrs)pl:l5.86.47.0pH4. 5-5.2pH5.8QHS QHSN6DCRLitvay1601-L-1WSWhiteB5DCRQHS L7(3-)QHSMg2+Fe2+Mn-2+NH4NO3KN03 ,KI,Ca-2+NH4N03KNOsMg2+Ca2+QHS TLCQHSQHS QHSQHSHPlQHS2 QHSQHS3QHS4QHSQHSQIS51601-L-115834-L-1
