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1.
Anomalous X-ray scattering experiments for glassy room-temperature superionic conductors (As2Se3)0.4 (AgI)0.6 and (As2Se3)0.4(AgBr)0.6 were performed close to the As, Se, Ag, and Br K edges using a third-generation synchrotron radiation facility, ESRF. The differential structure factors, ΔiS(Q), were obtained from detailed analyses, indicating that ΔAsS(Q) and ΔSeS(Q) of both the glassy superionic semiconductors are similar to those of glassy As2 Se3 except the prepeak in ΔSeS(Q). The ΔAgS(Q) spectrum of (As2Se3)0.4 (AgI)0.6 looks molten salt-like. However, the ΔAg S(Q) of (As2Se3)0.4(AgBr)0.6 glass have quite different features from that of (As2Se3)0.4 (AgI)0.6 glass in the low Q range, and the ΔBrS(Q) has even a pre-shoulder around 13 nm? 1 unlike molten salts. In the differential pair distribution functions Δig(r) obtained from the Fourier transforms of ΔiS(Q), the first peaks of ΔAsg(r) and ΔSeg(r) show no correlation with those of ΔAgg(r) and ΔBrg(r), and vice versa. From these results, it can be concluded that a pseudo-binary mixture of the As2Se3 network matrix and AgX-related ionic conduction pathways is a good structural model for these superionic glasses. Differences between the AgBr- and AgI mixtures were found in the second-neighbor structures around the Ag atoms, which may reflect those in the crystal structures of the AgX salts. 相似文献
2.
V. I. Lavrent’ev 《Physics of the Solid State》1998,40(3):354-357
The temperature variations in the modulus of elasticity (Young’s modulus) E and internal friction Q
−1 of the amorphous metal alloys Ti50Cu50−x
Nix (5⩽x⩽20) are studied at temperatures of 300–800 K. There is an anomalous increase in E(T) at temperatures above T
x (which varies from 440 to 525 K, depending on the composition). When the amount of nickel in the alloy is high (x>12 at. %), a small peak shows up in Q
−1(T). These effects are related to structural transitions in near-ordering regions (clusters). A model for structural relaxation
of near ordering in amorphous alloys is proposed on the basis of these experiments.
Fiz. Tverd. Tela (St. Petersburg) 40, 389–392 (March 1998) 相似文献
3.
A. A. Sorokin G. K. Ryasny B. A. Komissarova L. N. Fomicheva A. V. Tsvyashchenko S. M. Nikitin 《Hyperfine Interactions》2006,171(1-3):269-275
The perturbed angular correlation (PAC) measurements with the 111In-111Cd nuclear probe embedded into the lattice of the cubic (C15) Laves compound ZrZn2 showed that 111Cd nuclei experienced an axially symmetric electric quadrupole interaction with a frequency ν
Q
= 132.4 MHz at room temperature. The samples were synthesized and doped with the probe at a pressure 8 GPa. The temperature
dependence of ν
Q
was shown to be linear: ν
Q
(T) = 147(1 − 0.033 T) MHz. Since the value of ν
Q
is very close to that known for 111Cd in the lattice of Zn, we have checked if it could be assigned to residual Zn metal in the sample. For the Zn sample melted
and doped with 111In at 8 GPa we have obtained ν
Q
= 117.3 MHz at 300 K and 127 MHz at 80 K – both values considerably lower than that for 111In doped Zn samples prepared at an ambient pressure. These data, and the fact that ν
Q
(T) in Zn is known to follow the T
3/2 law, allow to attribute the ν
Q
value quoted above to 111Cd nuclei at the substitutional sites with tetrahedral symmetry in the Zn sublattice of ZrZn2. 相似文献
4.
Summary In the present review of liquid dynamics studies on liquid metals are reported. Particularly the case of liquid lead is reviewed
because this case was carefully studied by neutron scattering technique,S(Q,ω) being determined at two widely different temperaturesT=623 K andT=1170 K and therefore different densities. In addition extensive supplementary MD simulations were made using a 16 384-particle
system. The simulations ranged from a determination of an effective pair potential for lead to simulation of the density correlation
functionsF(Q,t) andF
s(Q,t), as well as the longitudinal and transversal current correlation functionsJ
1(Q,t) andJ
T(Q,t). The MD simulation ?calibrated? via the experimentalS(Q) andS(Q,ω) was used to prolong the range of neutron data to draw conclusions regarding such quantities as dispersion relations for
the current correlationsJ
1(Q,t) andJ
T(Q,t), the generalized viscosity functions ν1(Q,t), ν1(Q) and νs(Q). Information regarding bulk viscosity νB(Q) is also gained. Conclusions are drawn regarding the relative importance of the derived pair potential form by comparison
to corresponding hard-sphere data. The general framework of linearized hydrodynamic equations for the macroscopic situation
transforming to visco-elastic equations of motion for finite wave-length and high frequency works well also for the case of
a continuous potential. The region of transition from simple visco-elastic to hydrodynamic behaviour is occurring at wavelengths
in the range (12÷20) ? for the cases studied. The spatial properties of the viscosity functions ν1(r), νs(r) and νB(r) are found to correlate well with the range of the radial distribution function for the liquid. The general results for liquid
lead probably have wide range of applicability to other simple liquids with similarS(Q) andg(r) properties.
The authors have agreed not to receive proofs for correction. 相似文献
5.
D. Yamano Y. Sakamoto A. Yabushita M. Kawasaki I. Morino G. Inoue 《Applied physics. B, Lasers and optics》2009,97(2):523-528
Buffer-gas pressure broadening for the P(1), Q(1), R(0) and R(1) transitions in the 2ν
3 band of CH4 was investigated in the 1660 nm region. The pressure broadening coefficients, γ(gas), were determined for a variety of buffer gases: N2, O2, He, Ne, Ar, Kr and Xe. The γ values generally increased with increasing polarizability of the buffer gases. γ(air) are 0.056(2) for P(1), 0.056(1) for R(0), 0.061(1) for R(1) and 0.059(1) for Q(1) in units of cm−1 atm−1 where numbers in parentheses are one standard deviation in units of the last digits quoted. The temperature dependent parameter
(broadening exponent) for air is 0.84(7) for P(1) within the temperature range 233–298 K. 相似文献
6.
Guo-Yu Lan Yang-Wei Lin Zong-Hong Lin Huan-Tsung Chang 《Journal of nanoparticle research》2010,12(4):1377-1388
This article describes the synthesis of highly water-soluble Zn
x
Hg1−x
Se
y
S1−y
quantum dots (QDs) in aqueous solution through a simple photo-assisted reaction between ZnSe QDs and mercury(I) nitrate dihydrate
[Hg2(NO3)2·2H2O]. In order to deduce the optimal synthesis conditions, we varied several parameters, including the concentrations of mercaptosuccinic
acid (MSA) and Hg2(NO3)2·2H2O, the illumination time, and the reaction temperature. When irradiated at temperatures below 80 °C, the ZnSe QDs reacted
with the S2− ions formed rapidly from MSA and the Hg2+ ions formed from Hg2
2+ ions to form Zn
x
Hg1−x
Se
y
S1−y
QDs through a process of photo-etching and surface combination. Under different conditions, we prepared a series of Zn
x
Hg1−x
Se
y
S1−y
QDs that emit fluorescence at the maximum wavelengths ranging from 405 to 760 nm. Inductively coupled plasma-mass spectrometry
and transmission electron microscopy/energy dispersive spectrometry revealed that the content of Hg in the Zn
x
Hg1−x
Se
y
S1−y
QDs was greater when the synthesis was conducted at higher temperature. The Zn0.88Hg0.12Se0.44S0.56 QDs exhibit improved photostability than crude ZnSe QDs and possess long lifetimes (τ1 ~ 38 ns and τ2 ~ 158 ns). 相似文献
7.
Summary The dispersion of collective density fluctuations (extended sound modes) has been measured in mixtures of liquid alkali metals
and the corresponding molten alkali-halide salts. Mixtures with salt concentrations from 10 to 40% were investigated for momentum
transfersQ between 4 and 14 nm−1. ForQ-values larger than 11 nm−1 the collective modes could even in the most favourable case no longer be separated from the quasi-elastic peak, the width
of which increases roughly ∼Q
2 in this region of momentum transfers. At a concentration of 10% RbCl in Rb we find a dispersion which would correspond to
expanded liquid Rb at the temperature of the mixture (∼1000 K), demonstrating the dominant metallic character of the mixture
(screening by nearly free electrons) at this salt concentration. At higher concentrations of salt, where influences from different
partial dynamic structure factors interplay, the dispersions deviate from this simple structured dispersion curve, most likely
due to the influence of an early onset of some ionic type of screening in the liquid.
The proofs of this paper have been supervised by the Scientific Committee. 相似文献
8.
F. L. Bregolin M. Behar F. Dyment 《Applied Physics A: Materials Science & Processing》2009,95(2):501-505
The diffusion of nitrogen in α-Hf was studied in the temperature range of (823–1123) K using the ion implantation and nuclear resonance techniques. The
measurements show that the diffusion coefficients follow the Arrhenius behavior D(T)=D
0exp (−Q/RT) with D
0=(5.5±2.1)×10−7 m2/s and Q=(228±1) kJ/mol. A comparison of the present results with the previous one is done. 相似文献
9.
We have studied photoluminescence and thermoluminescence (PL and TL) in CaGa2Se4:Eu crystals in the temperature range 77–400 K. We have established that broadband photoluminescence with maximum at 571 nm
is due to intracenter transitions 4f6 5d–4f7 (8S7/2) of the Eu2+ ions. From the temperature dependence of the intensity (log I–103/T), we determined the activation energy (E
a = 0.04 eV) for thermal quenching of photoluminescence. From the thermoluminescence spectra, we determined the trap depths:
0.31, 0.44, 0.53, 0.59 eV. The lifetime of the excited state 4f6 5d of the Eu2+ ions in the CaGa2Se4 crystal found from the luminescence decay kinetics is 3.8 μsec.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 76, No. 1, pp. 112–116, January–February, 2009. 相似文献
10.
Corrections of order α
5 and α
6 to the hyperfine structure of S- and P-wave energy levels of the muonic-helium ion are calculated. Electron-vacuum-polarization effects, corrections for the nuclear
structure, and recoil effects are taken into account. The numerical values obtained for respective hyperfine splitting, −1334.73
meV (1S), −166.64 meV (2S), −58 712.90 μeV (2P
1/2), and −24 290.69 μeV (2P
3/2), can be viewed as a reliable estimate for a comparison with experimental data, and the hyperfine-structure interval of Δ12 = 8ΔE
hfs(2S) − ΔE
hfs(1S) = 1.59 meV can be used to test QED predictions. 相似文献
11.
12.
The integral energy spectrum of primary cosmic rays has been obtained. In the energy range (2.4×103−1.1×105 GeV), the spectrum of all nuclei is consistent with a power law of indexγ=1.55±0.06 and the flux of all nuclei is:N(⩾E
0)⋍(5.1±1.8)×10−1×E
0
−1.55
particles/cm2 sterad. sec., whereE
0 is in GeV. The spectrum of primaryα-particles in the energy range (4.4×103−4.8×104) GeV is also consistent with a power law of indexγ=1.71±0.12 and the flux is:N(⩾E
0)=(4.2±1.4)×10−1×E
0
−1.71
, particles per cm2 sterad. sec, whereE
0 is in GeV. 相似文献
13.
Water-soluble Mn2+-doped ZnS quantum dots (QDs) were prepared using mercaptoacetic acid as the stabilizer. The optical properties and structure
features were characterized by X-Ray, absorption spectrum, IR spectrum and fluorescence spectrum. In pH 7.8 Tris-HCl buffer,
the QDs emitted strong fluorescence peaked at 590 nm with excitation wavelength at 300 nm. The presence of sulfide anion resulted
in the quenching of fluorescence and the intensity decrease was proportional to the S2− concentration. The linear range was from 2.5 × 10−6 to 3.8 × 10−5 mol L−1 with detection limit as 1.5 × 10−7 mol L−1. Most anions such as F−, Cl−, Br−, I−, CH3CO2
−, ClO4
−, CO3
2−, NO2
−, NO3
−, S2O3
2−, SO3
2− and SO4
2− did not interfere with the determination. Thus a highly selective assay was proposed and applied to the determination of
S2− in discharged water with the recovery of ca. 103%. 相似文献
14.
The specific heat of undercooled liquid Ni80Fe10Cu10 alloy was experimentally measured by electromagnetic levitation drop calorimeter, and also numerically simulated by the molecular
dynamics method. The achieved maximum undercooling is up to 252 K (0.15 T
L) in the experiments, and the measured result is 41.67 J mol−1 K−1. The simulation provides calculated data within 0∼702 K undercooling range, which is much broader than the experimental regime.
The simulated value is 37.02 J mol−1 K−1. Although there exists a difference of 4.65 J mol−1 K−1 between them, the result is quite acceptable for simulation. Furthermore, the liquid structure of undercooled Ni80Fe10Cu10 alloy is studied in terms of the total and partial pair distribution functions, which display that the ordered degree of
atoms enhances from a normal liquid to metastable state. 相似文献
15.
In the present work, the excited states of 113Sb were populated in the 100Mo(20Ne, p6n) reaction at a beam energy of 136 MeV. States only up to 59/2− were observed in the ΔJ = 2 band. Mean lifetimes for the five states (from 4460 to 7998 keV) were measured for the first time using Doppler shift
attenuation method. An upper limit of the lifetime (0.14 ps) was estimated for the 9061 keV, 47/2− state. The B(E2) values, derived from the present lifetime results, correspond to a large quadrupole deformation of β
2 = 0.32. The observed reduction in the experimental B(E2) values for the 918.4 keV (spin 39/2− → 35/2−) and 985 keV (spin 43/2− → 39/2−) transitions may be interpreted as due to the proton alignement in the g
7/2 orbital. The dynamic moment of inertia was observed to be about half of the rigid body value at the highest observed frequency. 相似文献
16.
Alonso A Almendral MJ Curto Y Criado JJ Rodríguez E Manzano JL 《Journal of fluorescence》2007,17(4):390-400
The flow injection technique is applied to study the binding to DNA of new platinum complexes—E1: ethylenediaminechlorocholylglycinateplatinum(II): [PtCl(CG)(en)], C54H92O12Pt and E2: ethylenediaminebischolylglycinateplatinum(II): [Pt(CG)2(en)], C28H50ClN3O6Pt—derived from cisplatin in which the exchangeable ligands were replaced by bile acids, such that these anticancer drugs
have less toxicity and less resistance is developed towards them. Both compounds are fluorescent and their fluorescence is
enhanced when they form adducts with DNA, a property that is extremely useful for monitoring the cytotoxic activity and their
mechanisms of action. The binding parameters to DNA of E1 [apparent intrinsic binding constant KE1: (11.2 ± 0.4) × 103 M−1 and maximum number of binding sites per nucleotide, n
E1: 0.121 ± 2 × 10−3) and E2 (KE2: 9.2 ± 0.7) × 103 M−1 and n
E2 0.098 ± 2 × 10−3] were determined following the Scatchard method and the type of binding was studied experimentally through the modifications
introduced by each of the compounds into the ethidium bromide–DNA bond. 相似文献
17.
The binding of quercetin to lysozyme (LYSO) in aqueous solution was investigated by fluorescence spectroscopy, UV-vis absorption
spectroscopy and molecular simulation at pH 7.4. The fluorescence quenching of LYSO by addition of quercetin is due to static
quenching, the binding constants, K
a
, were 3.63 × 104, 3.31 × 104 and 2.85 × 104 L·mol−1 at 288, 298 and 308 K, respectively. The thermodynamic parameters, enthalpy change, ∆H, and entropy change, ∆S, were noted to be −7.56 kJ·mol−1 and 61.07 J·mol−1·K−1. The results indicated that hydrophobic interaction may play a major role in the binding process. The distance r between the donor (LYSO) and acceptor (quercetin) was determined as 3.34 nm by the fluorescence resonance energy transfer.
The synchronous fluorescence spectroscopy showed the polarity around the tryptophan residues increased and the hydrophobicity
decreased. Furthermore, the study of molecular simulation indicated that quercetin could bind to the active site (a pocket
made up of 24 amino-acid residues) of LYSO mainly via hydrophobic interactions and that there were hydrogen interactions between
the residues (Gln 57, Ile 98) of LYSO and quercetin. The accessible surface area (ASA) calculation verified the important
roles of tryptophan (Trp) residues during the binding process. 相似文献
18.
P. Birrer D. Cattani J. Cors M. Decroux Ø. Fischer F. N. Gygax B. Hitti E. Lippelt A. Schenck M. Weber 《Hyperfine Interactions》1991,63(1-4):103-108
We report on transverse field (300 mT)μ
+ SR measurements in the Chevrel phase superconductors SnMo6SySe8−y (y=1, 4, 7, 8) and PbMo6SzSe8−z (z=4.8) using the field cooling procedure (from room temperature down to 2.2 K). The London penetration depth λL was determined by the analysis of the fits with a single Gaussian relaxation function and by comparing the measured field
distributions with calculated ones, where a broadening due to small random displacements of the vortices was taken into account. 相似文献
19.
Correlation between the activation energyQ of high-temperature creep and the Debye-Waller thermal parameterB, which is proportional to the mean-square amplitude of atomic vibrations, has been examined in the case of 17 faced-centred
cubic, body-centred cubic and diamond-structure cubic elements. It is observed thatQ is a function ofB, irrespective of the crystal structure;Q decreases asB increases. The correlation is governed by the power-lawQ=Q
0(B/B
0)
M0
, whereQ
0=0.095eV andM
0=−0.62 are numerical constants determined by least-squares fit method, and the constantB
0=1 nm2. 相似文献
20.
We analyze the proton and deutron data on the spin-dependent asymmetry A
1(x, Q
2), supposing that the DIS structure functions g
1(x, Q
2) and F
3(x, Q
2) have a similar Q
2 dependence. As a result, we have found that Λ
1
p
−Λ
1
n
=0.190±0.038 at Q
2=10 GeV2 and Λ
1
p
−Λ
1
n
=0.165±0.026 at Q
2=3 GeV2; these values are in the best agreement with the Bjorken sum rule predictions.
Pis’ma Zh. éksp. Teor. Fiz. 65, No. 1, 9–14 (10 January 1997)
Published in English in the original Russian journal. Edited by Steve Torstveit. 相似文献