共查询到20条相似文献,搜索用时 15 毫秒
1.
M. A. Kudryashov A. I. Mashin A. A. Logunov G. Chidichimo G. De Filpo 《Technical Physics》2012,57(7):965-970
The frequency dispersion of the electrical conductivity of silver/polyacrylonitrile nanocomposite films is studied at various temperatures and AgNO3 contents in an initial mixture. The frequency dependences of the nanocomposites in the range 103?C106 Hz are found to be well described by power law f 0.8. A charge transfer mechanism responsible for the conductivity of the nanocomposites is proposed. Silver clusters Ag 4 2+ and Ag 8 2+ are assumed to be present in the polymer. 相似文献
2.
The pulsed electron electron double resonance (PELDOR) pulse sequence is applied to a three-spin system consisting of three radicals (Y D · , Y Z · and Q A ? ) generated in spinach PS II. The distance between YZ and QA has been determined to be 3.4 nm with the previously derived distances of the other radical pairs, 2.9 nm for Y D · -Y Z · and 3.9 nm for Y D · -Q A ? . This distance has been derived from the Y Z · -Q A ? radical pair trapped in YD-less mutants ofChlamydomonas reinhardtii. Furthermore the method was applied to the Y D · -Q A ? -Chl Z + system to find the unknown distance between QA and ChlZ. The derived distance was 3.4 nm. A triangular configuration was found in the membrane system that gives the relative positions of the electron transfer components. 相似文献
3.
The dichloromethanesulfonates of silver and other +1-charged cations, M ?+?(Cl2CHSO $_{3}^{-})$ (M = Ag, Tl, Li, Na, K, Rb, Cs) were synthesized and studied by 35Cl NQR. Dichloromethanesulfonic acid was prepared by the methanolysis of dichloromethanesulfonyl chloride, and was then neutralized with the carbonates of the +1-charged cations to produce the corresponding dichloromethanesulfonate salt. This NQR study completed the investigation of the chloroacetates and chloromethanesulfonates of silver, Ag?+?(Cl x CH3???x SO $_{3}^{-})$ and Ag?+?(Cl x CH3???x CO $_{2}^{-})$ , and suggests (1) that the ability of organochlorine atoms to coordinate to silver decreases as the number of electron-withdrawing groups (Cl, SO $_{3}^{-}$ , CO $_{2}^{-})$ attached to the carbon atom increases; (2) that the unusually large NQR spectral width found among M ?+?(Cl2CHCO $_{2}^{-})$ salts is not present among M ?+?(Cl2CHSO $_{3}^{-})$ salts, and therefore is not generally characteristic of the dichloromethyl group in salts. 相似文献
4.
N. V. Chukanov V. V. Nedelko L. N. Blinova L. A. Korshunova L. V. Olysych I. S. Lykova I. V. Pekov J. C. Buhl W. Depmeier 《Russian Journal of Physical Chemistry B, Focus on Physics》2012,6(5):593-600
Microporous framework aluminosilicates with the cancrinite- and sodalite-type structures containing NO 3 ? , CO 3 2? , SO 4 2? and PO 4 3? , as extra-framework anions were synthesized under hydrothermal conditions at temperatures from 160 to 200°C. SO 4 2? exhibits the highest affinity to cancrinite structure at the competition of various X anions. Chemical composition, X-ray diffractometry characteristics, and IR spectra of the compounds obtained, as well as kinetics and mechanism of thermal transformations of nitrate counterpart of cancrinite, were studied. 相似文献
5.
V. D. Frolov P. A. Pivovarov E. V. Zavedeeev M. S. Komlenok V. V. Kononenko V. I. Konov 《Applied Physics A: Materials Science & Processing》2014,114(1):51-55
Experimental data on laser ablation of highly oriented pyrolitic graphite by nanosecond pulsed UV ( $\lambda =193$ nm) and green ( $\lambda =532$ nm) lasers are presented. It was found that below graphite vaporization threshold $\approx $ 1 J/cm $^{2}$ , the nanoablation regime can be realized with material removal rates as low as 10 $^{-3}$ nm/pulse. The difference between physical (vaporization) and physical–chemical (heating + oxidation) ablation regimes is discussed. Special attention is paid to the influence of laser fluence and pulse number on ablation kinetics. Possibility of laser-induced graphite surface nanostructuring has been demonstrated. Combination of tightly focused laser beam and sharp tip of scanning probe microscope was applied to improve material nanoablation. 相似文献
6.
Oskar Asvany Sandra Brünken Lars Kluge Stephan Schlemmer 《Applied physics. B, Lasers and optics》2014,114(1-2):203-211
Two similar 4 K 22-pole trapping machines have been recently completed in our laboratory. As a first experimental test in one of them, CH 5 + and H3O+ ions have been trapped in the presence of helium gas at 3.8 K and the kinetics and temperature dependence of He tagging investigated. A first shell closure with 5 and (3 + 2) attached He atoms, respectively, is observed for both species. Applying IR radiation in the 3 μm region, helium attachment to CH 5 + is hindered by exciting CH-stretches of CH 5 + prior to attachment. The resulting spectroscopic signal shows that the kinetic temperature of the stored CH 5 + ensemble is below 12 K. 相似文献
7.
The electrochemical property of dinuclear copper(II) complex containing mixed ligands of N-hydroxyethylaminoethyl oxamido and 2,2′-bipyridine [Cu2(bpy)2(HAO) 2 2+ ] was studied with cyclic voltammetry. Cu2(bpy)2(HAO) 2 2+ had irreversible oxidation peaks in 0.1 mol/L NaCl solution at the stearic acid-modified carbon paste electrode. Cyclic voltammetry and absorption spectra measurements were used to study the interaction between Cu2(bpy)2(HAO) 2 2+ and herring fish sperm DNA. All the experimental results showed that Cu2(bpy)2(HAO) 2 2+ interacted with DNA mainly through electrostatic affinity to make tiny difference between Cu2(bpy)2(HAO) 2 2+ –ssDNA and Cu2(bpy)2(HAO) 2 2+ –dsDNA. The binding ratio and the binding constant of DNA–Cu2(bpy)2(HAO) 2 2+ were calculated as 1:1 and 6.41?×?104, respectively. The redox peak current of Cu2(bpy)2(HAO) 2 2+ decreased markedly after its interaction with DNA. This was used to detect the concentration of DNA quantitatively. 相似文献
8.
I. Blomqvist B. Bülow A. Fredrikson B. Johnsson G. G. Jonsson K. Lindgren M. Nilsson R. Petersson O. Glomset N. Freed W. Rhodes 《Zeitschrift für Physik A Hadrons and Nuclei》1978,284(3):313-317
The lifetime of the 331.3 keV 0 2 + state in100Zr has been measured at the gas-filled recoil separator for fission products JOSEF. By observing the delayed coincidences between theβ-particles populating the level and theE0 conversion electrons from its decay into the ground state, a half-life of 3.37±0.30 ns has been obtained. From the measured lifetime and the relative intensities of the 0 2 + →0 1 + and 0 2 + →2 1 + transitions, values of 0.493±0.015 for theE0 strength parameterρ, and of 16 single particle units forB(E2,2 1 + → 0 2 + ) have been deduced. The enhanced nature of theE0 transitions suggests mixing of the 0 1 + and 0 2 + states which may be estimated by comparing the experimentalB(E2) values for the 2 1 + →0 1 + and 2 1 + →0 2 + transitions with the predictions of the asymmetric VMI model. 相似文献
9.
A. V. Bulgakov O. F. Bobrenok V. I. Kosyakov I. Ozerov W. Marine M. Hedén F. Rohmund E. E. B. Campbell 《Physics of the Solid State》2002,44(4):617-622
Experimental results on the gas-phase formation of neutral and cationic phosphorus clusters are presented. The clusters were synthesized by visible (532 nm) or UV (193 nm) laser ablation of crystalline red phosphorus under high vacuum conditions and were analyzed using TOF mass spectrometry. Neutral Pn clusters produced by 532-nm ablation are found to be even-numbered while P n + cations are mainly odd-numbered, with P 7 + and P 21 + being the most abundant ions. For UV laser ablation, stable compound clusters, neutral P7H3 and P23H5, and cations P23H 6 + were synthesized for the first time. The formation of Pn clusters by thermal vaporization of red phosphorus into a cold He gas was also investigated and only small clusters (n<6) were found. Possible structures of the observed phosphorus clusters, as well as their formation mechanisms under different conditions, are discussed. 相似文献
10.
A. E. Stuchbery H. H. Bolotin C. E. Doran I. Morrison L. D. Wood H. Yamada 《Zeitschrift für Physik A Hadrons and Nuclei》1985,320(4):669-674
The gyromagnetic ratios of the 4 1 + , 6 1 + , and 2 2 + states in186W were measured relative to that of the 2 1 + level by means of the transient field implantation perturbedγ-ray angular distribution technique. The nuclei in the states of interest were Coulomb excited using a beam of 220-MeV63Cu projectiles and recoiled swiftly through a thin, polarized Fe foil. The present measurements yielded ratiosg(4 1 + )/g(2 1 + )=1.04±0.07,g(6 1 + )/g(2 1 + )=1.03 ±0.20 andg(2 2 + )/g(2 1 + )=0.63±0.13. The sizable disparity between the measuredg-factors of the ground- and excited-band is examined within the context of the interacting boson approximation model. 相似文献
11.
Yu. V. Zorenko 《Optics and Spectroscopy》2006,100(4):572-580
The time-resolved luminescence and luminescence excitation spectra, and luminescence decay kinetics at 8 and 300 K of Lu3A15O12 (LuAG) single-crystal films doped with Sc3+ and La3+ isoelectronic impurities and excited by synchrotron radiation are investigated. It is established that the La3+ isoelectronic impurity in the ?ub;c?ub; positions of the garnet lattice forms La Lu 3+ luminescence centers emitting in the band with λmax = 280 nm and the decay time of the main component τ = 300 ns at 300 K. The Sc3+ isoelectronic impurity located in the ?ub;c?ub; and (a) positions of the LuAG lattice forms two luminescence centers, Sc Lu 3+ and Sc Al 3+ , emitting in the bands with λmax = 290 nm and τ = 240 ns and λmax = 335 nm and τ = 375 ns, respectively, at 300 K. It is shown that the luminescence excitation of the La3+ and Sc3+ isoelectronic impurities in LuAG single-crystal films occurs through radiative decay of excitons localized near La Lu 3+ , Sc Lu 3+ , and Sc Al 3+ centers. The energies of formation of these excitons are determined to be 6.8, 6.88, and 7.3 eV, respectively. It was found that the excited state of the excitons genetically related to the La Lu 3+ , Sc Lu 3+ , and Sc Al 3+ enters has two radiative levels with different transition probabilities. This configuration leads to the presence of fast (2.3–8.4 ns) and slow (150–375 ns) main components in the luminescence of the centers formed by isoelectronic impurities in garnets. 相似文献
12.
F. Garcias J. A. Alonso J. M. López M. Barranco J. Németh 《Acta Physica Hungarica A》1995,1(3-4):227-240
A deformed-jellium model is used to calculate the fission barrier height of Na 24 2+ → Na 21 + +Na 3 + and Na 42 2+ → 2Na 21 + within the Kohn—Sham Density Functional Theory (i.e., including shell effects). Although the shape of the barrier obviously depends on the parametrization of the fission path, we have found that the barrier maximum corresponds to a configuration in which the emerging fragments are already formed and rather well apart. The two examples chosen serve to illustrate the influence of the electronic shell effects. 相似文献
13.
Dr. Heinz Prange 《Zeitschrift für Physik A Hadrons and Nuclei》1968,212(5):415-434
Using the Mössbauer technique electric hyperfine interactions of the first excited non-rotational states at 64 keV in157Gd and at 86.5 keV in155Gd have been determined in GdF3 and GdCl3· 6H2O. For the ratio of quadrupolmoments the ratiosQ 64 157 /Q g 157 =1.74±0.04,Q 86.5 155 /Q g 157 =?0.07 ± 0.21 andQ g 155 /Q g 157 =0.78 ± 0.06 were found. In addition isomer shifts were observed from which a ratio δ〈r2〉 64 157 /δ〈r2〉 86.5 155 =?2.6±0.15 can be inferred. 相似文献
14.
A technique for mass-spectrometric investigation of the yield of positive ions produced by direct and electron-impact dissociative ionization of methane molecules is described, and respective experimental data are presented. Doubly charged C 2 + , CH 3 2+ , and CH 4 2+ ions, as well as singly charged D 2 + , CD 3 + , and CD 4 + ions, are detected in the mass spectrum of a methane molecule at electron energy U e = 90 eV for the first time. From ionization efficiency curves, the ionization energy of the parent molecule and the appearance energy of fragment ions are determined. The ionization energy of the CH4 molecule is found to be 12.62 ± 0.20 eV. Electron-molecular reactions that may take place when a low-energy electron beam interacts with a methane molecule are analyzed. The ionization process and the formation of methane molecule fragments are studied. 相似文献
15.
M. Kopp M. Brower O. Mathieu E. Petersen F. Güthe 《Applied physics. B, Lasers and optics》2012,107(3):529-538
Chemiluminescence experiments have been performed to assess the state of current $\mathrm{CO}_{2}^{*}$ kinetics modeling. The difficulty with modeling $\mathrm{CO}_{2}^{*}$ lies in its broad emission spectrum, making it a challenge to isolate it from background emission of species such as CH? and CH2O?. Experiments were performed in a mixture of 0.0005H2+0.01N2O+0.03CO+0.9595Ar in an attempt to isolate $\mathrm{CO}_{2}^{*}$ emission. Temperatures ranged from 1654 K to 2221 K at two average pressures, 1.4 and 10.4 atm. The unique time histories of the various chemiluminescence species in the unconventional mixture employed at these conditions allow for easy identification of the $\mathrm{CO}_{2}^{*}$ concentration. Two different wavelengths to capture $\mathrm{CO}_{2}^{*}$ were used; one optical filter was centered at 415 nm and the other at 458 nm. The use of these two different wavelengths was done to verify that broadband $\mathrm{CO}_{2}^{*}$ was in fact being captured, and not emission from other species such as CH? and CH2O?. As a baseline for time history and peak magnitude comparison, OH? emission was captured at 307 nm simultaneously with the two $\mathrm{CO}_{2}^{*}$ filters. The results from the two $\mathrm{CO}_{2}^{*}$ filters were consistent with each other, implying that indeed the same species (i.e., $\mathrm{CO}_{2}^{*}$ ) was being measured at both wavelengths. A first-generation kinetics model for $\mathrm{CO}_{2}^{*}$ and CH2O? was developed, since no comprehensively validated one exists to date. CH2O? and CH? were ruled out as being present in the experiments at any measurable level, based on calculations and comparisons with the data. Agreement with the $\mathrm{CO}_{2}^{*}$ model was only fair, which necessitates future improvements for a better understanding of $\mathrm{CO}_{2}^{*}$ chemiluminescence as well as the kinetics of the ground state species. 相似文献
16.
Coulomb excitation byα-particles of vibrational-like states in even-mass rare-earth nuclei is used to determine the reduced transition probabilitiesB(E2; 0 gs + →2 γ + ),B(E2; 0 gs + →2 β + ),B(E2; 2 gs + →0 β + ) andB(E2; 0 gs + →3 oct ? ) in150Nd,152, 154Sm,154, 158Gd,164Dy and166Er. TheB(Eλ; 0 gs + →I=λ)-values range from 2.4 to 6.5 single-particle units for transitions to the 2 γ + -states, 0.8 single-particle units for the 2 β + -states and from 14.1 to 21.7 single-particle units for the 3?-states. 相似文献
17.
André Gleyzal 《Foundations of Physics》1974,4(1):23-30
A relative tensor calculus is formulated for expressing equations of mathematical physics. A tensor time derivative operator ▽ b a is defined which operates on tensors λia...ib. Equations are written in a rigid, flat, inertial or other coordinate system a, altered to relative tensor notation, and are thereby expressed in general flowing coordinate systems or materials b, c, d, .... Mirror tensor expressions for ▽ b a λic...id and ▽ b a λic...id exist in a relative geometry G if and only if a rigid coordinate system a exists in G, where ▽ b a λic = λ ,0c ic + λkev ckc aic + λ kc ic v b ckc , ▽jcλic = λ ,jc ic + λkcΓ jc kc ie , and v b aic is the velocity of b relative to a with components in c. These operators are convenient in theoretical analyses and can be incorporated into machine programs for the numerical solution of physical problems. 相似文献
18.
In this note the Kepler-Coulomb problem in hyperbolic space H 2 2 : z 0 2 + z 1 2 ? z 2 2 ? z 3 2 = R 2 is discussed. 相似文献
19.
Anton Savitsky Oksana Gopta Mahir Mamedov John H. Golbeck Alexander Tikhonov Klaus M?bius Alexey Semenov 《Applied magnetic resonance》2010,37(1-4):85-102
Photosystem I (PS I) mutants from the cyanobacterium Synechocystis sp. PCC 6803 bearing point mutations to the axial ligands of A0A (M688NPsaA) and A0B (M668NPsaB) were studied by high-field W-band electron paramagnetic resonance (EPR) spectroscopy. It was found that the EPR observables of PS I from the M668NPsaB mutant were virtual identical to that of the wild type (WT), and are clearly distinct from the M688NPsaA mutant. In particular, the P 700 ·+ decay kinetics in the M688NPsaA mutant is significantly slower than in the WT or the M668NPsaB mutant. The analysis of the out-of-phase electron–electron dipolar electron spin echo envelope modulation shows that in the M668NPsaB mutant, the estimated distance of 26.0 ± 0.3 Å agrees well with the 25.8 Å distance for the P 700 ·+ A 1A ·? radical pair measured in the X-ray crystal structure. In the M688NPsaA mutant, two populations are found with estimated distances of 26.0 ± 0.3 and 25.0 ± 0.3 Å in a ratio of 0.7–0.3, which agree well with the 25.8 Å distance for the P 700 ·+ A 1A ·? radical pair and the 24.6 Å distance for the P 700 ·+ A 1B ·? radical pair measured in the X-ray crystal structure. The data confirm that under the experimental conditions employed in this work, which involve dark-adapted samples without the pre-reduction of the iron–sulfur clusters, electron transport in cyanobacterial PS I is asymmetrical at 100 K, with the majority of electron transfer taking place through the A-branch of cofactors. 相似文献
20.
Munemi Miyamoto 《Communications in Mathematical Physics》1985,98(2):253-258
Consider the 1/2-Ising model inZ 2. Let σ j be the spin at the site (j, 0)∈Z 2 (j=0, ±1, ±2, ...). Let \(\{ X_n \} _{n = 0}^{ + \infty } \) be a random walk with the random transition probabilities such that $$P(X_{n + 1} = j \pm 1|X_n = j) = p_j^ \pm \equiv 1/2 \pm v(\sigma _j - \mu )/2$$ We show a case whereE[p j + ≧E[p j ? ], but \(\mathop {\lim }\limits_{n \to \infty } X_n = - \infty \) is recurrent a.s. 相似文献