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1.
Sodium phosphate glass undoped and doped with different concentrations of chlorides of iron, manganese, and zinc were prepared
by melt quenching. The synthesized glasses were characterized by elemental analysis, X-ray diffraction, infrared (IR) spectroscopy,
differential scanning calorimetry, and electrical conductivity studies. The undoped sodium phosphate glass (Na2O–P2O5) has low electrical conductivity σ compared to all doped glasses except for 10% FeCl3-doped samples for which σ is found to be the lowest, and the trend is
The Na2O–P2O5–5% ZnCl2, Na2O–P2O5–5% MnCl2 and Na2O–P2O5–1% FeCl3 glassy systems yielded maximum σ values. These results are explained on the basis of changes in the structure of sodium phosphate glass matrix by the addition
of Fe, Mn, and Zn ions based on IR spectra and DSC studies. 相似文献
2.
Lixin Xu Wenbo Li Jianbo Lu 《The European Physical Journal C - Particles and Fields》2009,60(1):135-140
In this paper, the holographic dark-energy model is considered in Brans–Dicke theory, where the holographic dark-energy density
ρ
Λ
=3c
2
M
pl2
L
−2 is replaced by ρ
h=3c
2
Φ(t)L
−2. Here
is the time-variable Newton constant. With this replacement, it is found that no accelerated expansion for the universe will
be achieved when the Hubble horizon is taken to play the role of an IR cut-off. When the event horizon is adopted as the IR
cut-off, accelerated expansion for the universe is obtained. In this case, the equation of state of holographic dark energy,
w
h, takes the modified form
. In the limit α→0, the ‘standard’ holographic dark energy is recovered. In the holographic dark-energy dominated epoch, power-law and de
Sitter time-space solutions are obtained. 相似文献
3.
We address the decay of the norm of weak solutions to the 2D dissipative quasi-geostrophic equation. When the initial data
θ0 is in L
2 only, we prove that the L
2 norm tends to zero but with no uniform rate, that is, there are solutions with arbitrarily slow decay. For θ0 in L
p
∩ L
2, with 1 ≤ p < 2, we are able to obtain a uniform decay rate in L
2. We also prove that when the norm of θ0 is small enough, the L
q
norms, for , have uniform decay rates. This result allows us to prove decay for the L
q
norms, for , when θ0 is in .
The second author was partially supported by NSF grant DMS-0600692. 相似文献
4.
A novel and ultrasensitive resonance scattering (RS) spectral assay was proposed for detection of horseradish peroxidase (HRP)
activity. It was based on that the HRP strongly catalyze H2O2 oxidation of excess I− to form , the resulting combined with four cationic surfactant (CS), including tetradecyl pyridinium bromide (TPB), cetyltrimethyl ammonium bromide
(CTMA), cetylpyridinium chloride (CPCM) and tetradecyl dimethylbenzyl ammonium chloride (TDMBA) to produce association particles
(TPB-I3)
n
, (CTMA-I3)
m
, (CPCM-I3)l and (TDMBA-I3)
k
, which exhibit a strongest resonance scattering peak at 478, 423, 538 and 491 nm, respectively. For the four systems of TPB,
CPCM, CTMBA and TDMBA, the HRP activity determined was in the linear range of 0.004–5.6, 0.04–3.2, 0.04–8.0, 0.08–8.0 ng/mL,
with a detection limit of 0.0034, 0.040, 0.033, 0.016 ng/mL, respectively. The TPB resonance scattering spectral assay was
best and has been applied to the analysis of HRP in real samples, with satisfactory results. 相似文献
5.
We investigate the spectroscopic properties of the 1.5-μm emission from the 4I13/2 → 4I15/2 transition of Er3+ ions in PbO–Bi2O3–Ga2O3–GeO2 glasses for applications in broadband fiber amplifiers. The measured emission peak locates at 1,532 nm with a full width
at half-maximum of ∼45 nm. The glasses exhibit a large stimulated emission cross-section of 0.89 × 10−20 cm2 and a large product of 40.0. Infrared-to-green upconversion occurs simultaneously upon excitation of the 1.5-μm emission with a commercially
available 980 nm laser diode. The green-upconversion intensity has a quadratic dependence on incident pump laser power, indicating
a two-photon process. Energy transfer processes and nonradiative phonon-assisted decays could account for the population of
the 2H11/2 of Er3+. The results indicate the possibility towards the development of lead–bismuth–gallate–germanate based glasses as photonics
devices. 相似文献
6.
We study the exclusive Λb→Λℓ+ℓ- decay in the Appelquist, Chang, Dobrescu model with a single universal extra dimension. We investigate the sensitivity of
the branching ratio, lepton polarization and forward–backward asymmetry to the compactification parameter 1/R. We obtain the result that the branching ratio for the Λb→Λℓ+ℓ- (ℓ=μ,τ) decay changes about 25% compared to the SM value when 1/R=250 GeV, and the zero position of the forward–backward
asymmetry is shifted to the left compared to the SM result. Therefore, measurement of the branching ratio of Λb→Λℓ+ℓ- decay and determination of the zero position of are very useful in looking for new physics in the framework of the UED models.
PACS 12.60.-i; 13.30.-a; 14.20.Mr 相似文献
7.
G. Abbiendi et al. 《The European Physical Journal C - Particles and Fields》2006,45(2):307-335
The mass and width of the W boson are measured using e+e– → W+W– events from the data sample collected by the OPAL experiment at LEP at centre-of-mass energies between 170 GeV and 209 GeV.
The mass (mW) and width (ΓW) are determined using direct reconstruction of the kinematics of W+W– →
and W+W– →
events. When combined with previous OPAL measurements using W+W– →
events and the dependence on of the WW production cross-section at threshold, the results are determined to be
where the first error is statistical, the second systematic and the third due to uncertainties in the value of the LEP beam
energy. By measuring in the channel using several different determinations of the direction of jets with differing sensitivities
to soft particles, a limit is also obtained on possible final-state interactions due to colour reconnection effects inW+W– →
events. The consistency of the results for the W mass and width with those inferred from other electroweak parameters provides
an important test of the Standard Model of electroweak interactions.
Arrival of the final proofs: 28 November 2005
This paper is dedicated to the memory of Steve O'Neale 相似文献
8.
Given a one dimensional perturbed Schrödinger operator H = ? d 2/dx 2 + V(x), we consider the associated wave operators W ± , defined as the strong L 2 limits $\lim_{s\to\pm\infty}e^{isH}e^{-isH_{0}}Given a one dimensional perturbed Schr?dinger operator H = − d
2/dx
2 + V(x), we consider the associated wave operators W
± , defined as the strong L
2 limits
. We prove that W
± are bounded operators on L
p
for all 1 < p < ∞, provided
, or else
and 0 is not a resonance. For p = ∞ we obtain an estimate in terms of the Hilbert transform. Some applications to dispersive estimates for equations with
variable rough coefficients are given. 相似文献
9.
J.X. Zuo J.Y. Chen X.Z. Cai Y.G. Ma F. Liu P. Sorensen A.H. Tang H.Z. Huang J.H. Chen G.L. Ma C. Zhong 《The European Physical Journal C - Particles and Fields》2008,55(3):463-467
The elliptic flow v2 and the fourth order anisotropic flow v4 of (Ω+Ω̄) have been studied in the framework a parton–hadronic transport model, namely a multi-phase transport (AMPT) model,
for 197Au+197Au collisions at = 200 GeV and 62.4 GeV. The transverse momentum (pT) and the transverse kinetic energy (mT-m0) dependence of v2 and v4 are presented. The calculation in the AMPT model seems consistent with the STAR data. The results show that the v2 of (Ω+Ω̄) in 200 GeV obeys the constituent quark number scaling that has been observed for other mesons and baryons. Comparison
of (Ω+Ω̄) elliptic flow v2 in the default version of AMPT, the melting version of AMPT and the RQMD model calculation, shows that the parton cascade
process is important to reproduce the sizeable v2, and the string melting AMPT model preferably reproduces (Ω+Ω̄) elliptic flow v2 in 197Au+197Au collisions at = 200 GeV. The v2 of (Ω+Ω̄) in the 62.4 and 200 GeV collisions seem similar, and the pT dependence of (Ω+Ω̄) baryons’ v4 in 62.4 GeV and 200 GeV looks also similar in the string melting AMPT model, which indicates that a similar partonic matter
phase has been reached in both energies. 相似文献
10.
Riazuddin 《The European Physical Journal C - Particles and Fields》2007,51(3):697-699
It is proposed that light neutrinos form a triplet in a global SU(3) symmetry in the mass eigenstate basis. Assuming that
the SU(3) symmetry is broken in the direction , and after going to the flavor basis, we predict the atmospheric mixing angles sin2θ23=0.5 and sinθ13=0, if νμ–ντ symmetry is assumed. In the flavor basis, the diagonal part of the matrix coefficient of b (the dominant part) is found to
transform like . Imposing the same condition on the matrix coefficient of a fixes the solar mixing angle, . The implications for neutrinoless double beta decay are discussed. 相似文献
11.
Polycrystalline perovskite Pb(Zr
x
Ti O3 (PZT) powders in the form of particles with sizes in the range 2∼
∼10 nm were obtained by hydrolysis of a mixed metal alkoxide precursor. The mixed metal alkoxide precursor was synthesized by refluxing Pb(OAc)2, Zr(O–
n
Bu)4 and Ti(O–iPr)4 in anhydrous ethanol. After it was hydrolyzed in a solution with a pH of 3 and dried at 423 K, nano-sized polycrystalline perovskite PZT was obtained. This temperature of formation of the PZT perovskite phase is noticeably lower than those reported elsewhere. The sizes of the freshly dried polycrystalline perovskite PZT particles are within the range of 2–5 nm. 相似文献
12.
Nearly a 50% decrease of the resistivity ρ(T, x) is observed upon just 4% Cu doping at the Mn site of La2/3Ca1/3Mn1−x
CuxO3. When the observed phenomenon is attributed to a decrease of the spin-polaron energy E
σ(x) below T
C
(x), all of the data are found to be well fitted by the nonthermal coherent tunneling expression
, assuming that the magnetization in the ferromagnetic state is given by the expression
. The best fits through all the data points suggest
and E
σ(x)≃E
σ(0)(1−x)4 for the explicit x dependence of the Cu-induced modifications of the Mn-spin-dominated zero-temperature spontaneous magnetization, residual
paramagnetic contribution, and spin-polaron tunneling energy, respectively, with E
σ(0)=0.12 eV.
Pis’ma Zh. éksp. Teor. Fiz. 69, No. 11, 812–815 (10 June 1999)
Published in English in the original Russian journal. Edited by Steve Torstveit. 相似文献
13.
For weakly non ergodic systems, the probability density function of a time average observable
is
where
is the value of the observable when the system is in state j=1,…L. p
j
eq is the probability that a member of an ensemble of systems occupies state j in equilibrium. For a particle undergoing a fractional diffusion process in a binding force field, with thermal detailed
balance conditions, p
j
eq is Boltzmann’s canonical probability. Within the unbiased sub-diffusive continuous time random walk model, the exponent 0<α<1 is the anomalous diffusion exponent 〈x
2〉∼t
α
found for free boundary conditions. When α→1 ergodic statistical mechanics is recovered
. We briefly discuss possible physical applications in single particle experiments. 相似文献
14.
A new solid substrate-room temperature phosphorescence (SS-RTP) method for the determination of trace manganese (II) has been
established. It bases on the fact that fullerol (R) emits strong and stable room temperature phosphorescence (RTP) on filter
paper substrate. H2O2 can oxidize R to cause the SS-RTP quenching. But manganese (II) can obstruct H2O2 to oxidize R, and enhance the RTP of R. α,α′-Bipyridine (Bipy) can sensitize the RTP. After adding Bipy, the ΔI
p enhances 7 times than that without Bipy. Under the optimum conditions, the linear dynamic range of this method is 0.016–1.12 pg spot−1 with a detection limit (L.D.) of 4.6 fg spot−1 ( is the absolute mass of Mn2+), and the regression equation of working curve is ΔI
p=25.20 + 63.55 (pg spot−1), n=6, r=0.9983. For 0.016 and 1.12 pg spot−1 Mn2+, RSDS are 4.3 and 4.8%, respectively (n=7). This method has been applied to the determination of trace manganese (II) in actual sample with high sensitivity and
good selection. And the reaction mechanism of SS-RTP is discussed. 相似文献
15.
K. Kumagai K. Kakuyanagi M. Saitoh Y. Matsuda M. Hasegawa S. Takashima M. Nohara H. Takagi 《Hyperfine Interactions》2004,159(1-4):87-93
Spatially-resolved NMR is used to probe internal structures in highly correlated superconductors of optimally-doped (T
c
= 85 K) and a heavy fermion superconductor CeCoIn5 (T
c
= 2.3 K). The characteristic change of the properties of 205Tl-NMR in the vortex state provides a clear evidence of the antiferromagnetic order in the vortex cores below 20 K in . We also obtain anomalous 115In-NMR spectra of CeCoIn5, which provides a microscopic evidence for the occurrence of a spatially-modulated superconducting order parameter expected
in a Fulde–Ferrel–Larkin–Ovchinnkov (FFLO) state. 相似文献
16.
A dense (BCSO) membrane was fabricated by a modified suspension spraying on porous NiO–BCSO anode support. In the process, the suspension
was directly prepared by ball-milling the BaCO3, CeO2, and Sm2O3 powders in ethanol. A dense and uniform electrolyte layer in the thickness of 10 μm was successfully prepared on porous anode
support by suspension spray process after co-sintering at 1,400 °C for 5 h. With (NSMO) cathode, a single cell was assembled and tested with hydrogen and ammonia as fuels, respectively. The hydrogen-fueled
cell exhibits 1.01 V for open circuit voltage (OCV) and 560 mW/cm2 for peak power density at 700 °C. In comparison, the cell in ammonia displays a similar performance (1.02 V for OCV and 530 mW/cm2 for output), which indicates the liquid ammonia is a promising substitute for hydrogen. Moreover, the fuel cell displays
good interface contacts. To sum up, ammonia-fueled solid oxide fuel cells prepared by this simple suspension spray is an alternative
way to promote the commercialization. 相似文献
17.
G. Gritzner J. Ammer K. Kellner V. Kavečanský M. Mihalik S. Maťaš M. Zentková 《Applied Physics A: Materials Science & Processing》2008,90(2):359-365
La0.67Pb0.33(Mn1-xCox)O3-δ ceramics with x=0, 0.01, 0.03, 0.06, 0.1 and 0.15 have been prepared in a two-step procedure. Precursor gels were made by
the wet chemical malic acid method. The gels were calcined and then converted into ceramics by heat treatment at 950 °C and
1000 °C in air. X-ray diffraction showed that the compounds were phase pure. The crystal structure symmetry of the compounds
was confirmed to be rhombohedral (space group R3̄c) for the whole investigated range of x. All compounds undergo a paramagnetic–ferromagnetic
phase transition between 335 K and 225 K. The basic magnetic characteristics such as the Curie temperature , the paramagnetic Curie temperature θ, the effective magnetic moment and the saturated magnetization decrease with increasing Co doping. The ferromagnetic transition is accompanied by an anomaly in the electrical resistance
for all compounds. The high-temperature insulator–metal transitions () do not coincide with the relevant . A large magnetoresistance peak of about 15% was observed for all compounds at .
PACS 72.80.Ga; 75.47.Lx; 75.60.Ej 相似文献
18.
In this paper, an error in the proof of Theorem 4.9 in Gudder’s paper (Int. J. Theor. Phys. 47(1):268–279, 2008) is pointed out and it is proved that if
such that E
i
∈ℂI∖{0} and E
j
∉ℂI for some i,j in {1,2,…,n}, then
.
This subject is supported by the NNSF of China (No. 10571113, 10871224). 相似文献
19.
Several modifications of the faradaic efficiency and electromagnetic field (EMF) methods, taking electrode polarisation resistance
into account, were considered based on the analysis of ion transport numbers and p-type electronic conductivity of ceramics at 973–1,223 K. In air, the activation energies for p-type electronic and oxygen ionic transport are 115 ± 9 and
71 ± 5 kJ/mol, respectively. The oxygen ion transference numbers vary in the range 0.992–0.999, increasing when oxygen pressure
or temperature decreases. The apparent electronic contribution to the total conductivity, estimated from the classical faradaic
efficiency and EMF techniques was considerably higher than true transference numbers due to a non-negligible role of interfacial
exchange processes. The modified measurement routes give reliable and similar results when p(O2) values at the electrodes are high enough, whilst decreasing the oxygen pressure leads to a systematic error for all techniques
associated with measurements of concentration cell EMF. This effect, presumably due to diffusion polarisation, increases with
decreasing temperature. The most reliable results in the studied p(O2) range were provided by the modified faradaic efficiency method. 相似文献
20.
J. Bielcikova 《The European Physical Journal C - Particles and Fields》2007,49(1):321-326
We present results on two-particle azimuthal correlations of neutral strange baryons (Λ, Λ̄) and mesons (KS
0) for pT=2–6 GeV/c associated with non-identified charged particles in d+Au and Au+Au collisions at =200 GeV measured by the STAR experiment. We investigate in detail the associated yield of charged particles as a function
centrality of the collision and transverse momentum of trigger and associated particles to look for possible flavor, baryon/meson
and particle/anti-particle differences. We compare our results to the proton and pion triggered correlations as well as to
a fragmentation and recombination model.
PACS 25.75.-q; 25.75.Gz 相似文献