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1.
In this work, the fungus Penicillium was used for rapid extra-/intracellular biosynthesis of gold nanoparticles. AuCl4
− ions reacted with the cell filtrate of Penicillium sp. resulting in extracellular biosynthesis of gold nanoparticles within 1 min. Intracellular biosynthesis of gold nanoparticles
was obtained by incubating AuCl4
− solution with fungal biomass for 8 h. The gold nanoparticles were characterized by means of visual observation, UV–Vis absorption
spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive
X-ray spectroscopy (EDX). The extracellular nanoparticles exhibited maximum absorbance at 545 nm in UV–Vis spectroscopy. The
XRD spectrum showed Bragg reflections corresponding to the gold nanocrystals. TEM exhibited the formed spherical gold nanoparticles
in the size range from 30 to 50 nm with an average size of 45 nm. SEM and TEM revealed that the intracellular gold nanoparticles
were well dispersed on the cell wall and within the cell, and they are mostly spherical in shape with an average diameter
of 50 nm. The presence of gold was confirmed by EDX analysis. 相似文献
2.
Zhan-Shuo Hu Fei-Yi Hung Shoou-Jinn Chang Kuan-Jen Chen Yi-Wei Tseng Bohr-Ran Huang Bo-Cheng Lin Wei-Yang Chou Jay Chang 《Journal of nanoparticle research》2011,13(10):4757-4763
The photo-current of n-ZnO/p-Si heterojunction photodiodes was improved by embedding Ag nanoparticles in the interface (ZnO/nano-PAg/p-Si), and the ratio between photo- and dark-current increased by about three orders more than that of a n-ZnO/p-Si specimen. The improvement in the photo-current resulted from the light scattering of embedded Ag nanoparticles. The I–V curve of n-ZnO/p-Si degraded after thermal treatment (A-ZnO/p-Si) because the silicon robbed the oxygen from ZnO to form amorphous silicon dioxide and left an oxygen vacancy. Notably,
the properties of ZnO/nano-PAg/p-Si were better in the time-dependent photoresponse under 10 V bias. Ag nanoparticles (15–20 nm) scattered the UV light randomly
and increased the probability for the absorption of ZnO to enhance the properties of the photodiode. 相似文献
3.
Monica Ruffini Castiglione Lucia Giorgetti Chiara Geri Roberto Cremonini 《Journal of nanoparticle research》2011,13(6):2443-2449
This study aimed to provide new information about phyto-toxicology of nano-TiO2 on plant systems. To contribute to the evaluation of the potential harmful effects of the nanoparticles on monocots and dicots
we considered their effects on seed germination and root elongation applying a concentration range from 0.2 to 4.0‰ in the
plants Zea mays L. and Vicia narbonensis L. Moreover, we achieved a genotoxicity study at cytological level in root meristems by means of traditional cytogenetic
approach, to evidence possible alterations in mitotic activity, chromosomal aberrations, and micronuclei release. From these
analyses it comes out that nano-TiO2 particles, after short-term exposure and under our experimental conditions, delayed germination progression for the first
24 h in both materials. Root elongation was affected only after treatment with the higher nano-TiO2 concentration. Further significant effects were detected showing mitotic index reduction and concentration-dependent increase
in the aberration emergence that evidenced a nano-TiO2-induced genotoxic effect for both species. 相似文献
4.
Y. Xiao Y. Su C. M. N. Kumar C. Ritter R. Mittal S. Price J. Perßon Th. Brückel 《The European Physical Journal B - Condensed Matter and Complex Systems》2011,82(2):113-121
The physical and structural properties of Fe1.11Te and
Fe1.11Te0.5Se0.5 have been investigated by means of
X-ray and neutron diffraction as well as physical property
measurements. For the Fe1.11Te compound, the structure
distortion from a tetragonal to monoclinic phase takes place at 64 K
accompanied with the onset of antiferromagnetic order upon cooling.
The magnetic structure of the monoclinic phase was confirmed to be
of antiferromagnetic configuration with a propagation vector
k = (1/2, 0, 1/2) based on Rietveld refinement of neutron
powder diffraction data. The structural/magnetic transitions are
also clearly visible in magnetic, electronic and thermodynamic
measurements. For superconducting Fe1.11Te0.5Se0.5
compound, the superconducting transition with T
c
= 13.4 K
is observed in the resistivity and ac susceptibility measurements.
The upper critical field H
c2 is obtained by measuring
the resistivity under different magnetic fields. The Kim’s critical
state model is adopted to analyze the temperature dependence of the
ac susceptibility and the intergranular critical current density is
calculated as a function of both field amplitude and temperature.
Neutron diffraction results show that
Fe1.11Te0.5Se0.5 crystalizes in tetragonal structure
at 300 K as in the parent compound Fe1.11Te and no structural
distortion is detected upon cooling to 2 K. However an anisotropic
thermal expansion anomaly is observed around 100 K. 相似文献
5.
M. van Leeuwen 《The European Physical Journal C - Particles and Fields》2009,61(4):569-574
We present selected recent results of multi-hadron correlation measurements in azimuth and pseudorapidity at intermediate
and high p
T
in Au+Au collisions at
, from the STAR experiment at RHIC. At intermediate p
T
, measurements are presented that attempt to determine the origin of the associated near-side (small Δφ) yield at large pseudo-rapidity difference Δη that is found to be present in heavy ion collisions. In addition, results are reported on new multi-hadron correlation measures
at high-p
T
that use di-hadron triggers and multi-hadron cluster triggers with the goal to constrain the underlying jet kinematics better
than in the existing measurements of inclusive spectra and di-hadron correlations. 相似文献
6.
K. Ghorbani M. M. Yazdanpanah A. Mirjalili 《The European Physical Journal C - Particles and Fields》2011,71(6):1671
We calculate the scalar semileptonic kaon decay in finite volume at the momentum transfer t
m
=(m
K
−m
π
)2, using chiral perturbation theory. At first we obtain the hadronic matrix element to be calculated in finite volume. We then
evaluate the finite size effects for two volumes with L=1.83 fm and L=2.73 fm and find that the difference between the finite volume corrections of the two volumes are larger than the difference
as quoted in Boyle et al. (Phys. Rev. Lett. 100:141601, 2008). It appears then that the pion masses used for the scalar form factor in ChPT are large which result in large finite volume
corrections. If appropriate values for pion mass are used, we believe that the finite size effects estimated in this paper
can be useful for lattice data to extrapolate at large lattice size. 相似文献
7.
A comparative investigation of the magnetic properties of amorphous nanogranular composites (Co41Fe39B20)
x
(SiO
n
)100 − x
and (Co86Nb12Ta2)
x
(SiO
n
)100 − x
has been performed in the subpercolation region at temperatures in the range 4.2–300 K. The thermomagnetic dependences in
the range 4.2–300 K and the processes of magnetization reversal and remanent magnetization relaxation at liquid-helium temperatures
have been studied. It has been established that the average anisotropy constants of amorphous nanograins are equal to 3.6–7.0
kJ/m3 for the (Co41Fe39B20)
x
(SiO
n
)100 − x
composites and 5–8 kJ/m3 for the (Co86Nb12Ta2)
x
(SiO
n
)100 − x
composites. The fundamental differences in the concentration dependences of the anisotropy constant K
eff and the coercive force H
C
have been revealed for the two systems under investigation. It has been demonstrated that, as the concentration of the metal
phase increases, the quantities K
eff and H
C
increase for the (Co86Nb12Ta2)
x
(SiO
n
)100 − x
composites and decrease for the (Co41Fe39B20)
x
(SiO
n
)100 − x
composites. 相似文献
8.
J. Gasser B. Kubis N. Paver M. Verbeni 《The European Physical Journal C - Particles and Fields》2005,40(2):205-227
Motivated by recent experimental results and ongoing measurements, we review the chiral perturbation theory prediction for
decays. Special emphasis is given to the stability of the inner bremsstrahlung-dominated relative branching ratio versus the K
e3 form factors, and on the separation of the structure-dependent amplitude in differential distributions over the phase space. For the structure-dependent terms, an assessment of the order p
6 corrections is given, in particular, a full next-to-leading order calculation of the axial component is performed. The experimental analysis of the photon energy spectrum is discussed, and other potentially useful distributions are introduced.Received: 9 December 2004, Published online: 21 February 2005PACS:
13.20.Eb, 11.30.Rd, 12.39.Fe 相似文献
9.
We use an appropriate combination of moments of finite energy sum rules in QCD in order to compute the B
q
-meson decay constants f
B
and
. We perform the calculation using a two-loop computation of the imaginary part of the pseudoscalar two point function in terms of the running bottom quark mass. The results are stable against the so-called QCD duality threshold, and they are in agreement with the estimates obtained from Borel transform QCD sum rules and lattice computations.Received: 28 July 2004, Revised: 10 September 2004, Published online: 23 November 2004PACS:
12.38.Bx, 12.38.LgSupported by MCYT-FEDER under contract FPA2002-00612. 相似文献
10.
Ivan I. Stoikov Elena A. Yushkova Igor S. Antipin Alexander I. Konovalov 《Journal of nanoparticle research》2011,13(12):6603-6611
The effect of solvent nature and temperature on the formation of 3D-dimensional SAM (self-assembled monolayers on nanoparticles)
based on synthetically available stereoisomers of p-tert-butyl thiacalix[4]arenes tetrasubstituted at the lower rim by pyrrolidide and octylamide groups (cone, partial cone, and 1,3-alternate) with lithium and silver nanoparticles were determined by dynamic light-scattering and transmission electron microscopy.
It was found that the variation of the temperature of the system and the nature of the solvent leads to the formation discrete
or extended particles (CH2Cl2) (98–110 nm), nanostructures (CH3CN) (120–295 nm) or three-dimensional SAM (DMF) (1–13 nm; 46–622 nm). 相似文献
11.
S. R. Gevorkyan A. N. Sissakian A. V. Tarasov H. T. Torosyan O. O. Voskresenskaya 《Physics of Atomic Nuclei》2010,73(6):961-964
The final-state interaction of pions in K
e4 decay allows to obtain the value of the isospin and angular-momentum-zero ππ scattering length a
00.We take into account the electromagnetic interaction of pions and isospin-symmetry-breaking effects caused by different masses
of neutral and charged pions and estimate the impact of these effects on the procedure of scattering-length extraction from
K
e4 decays. 相似文献
12.
M. Hamani Daouda Manuel E. Rodrigues M. J. S. Houndjo 《The European Physical Journal C - Particles and Fields》2012,72(2):1893
We develop the reconstruction of the f(T) gravity model according to the holographic dark energy. T is the torsion scalar and its initial value from the teleparallel gravity is imposed for fitting the initial value of the
function f(T). The evolutionary nature of the holographic dark energy is essentially based on two important parameters, Ω
V
and ω
V
, respectively, the dimensionless dark energy and the parameter of the equation of state, related to the holographic dark
energy. The result shows a polynomial function for f(T), and we also observe that, when Ω
V
→1 at the future time, ω
V
may cross −1 for some values of the input parameter b. Another interesting aspect of the obtained model is that it provides a unification scenario of dark matter with dark energy. 相似文献
13.
U. Aglietti F. Di Lodovico G. Ferrera G. Ricciardi 《The European Physical Journal C - Particles and Fields》2009,59(4):831-840
By analyzing B→X
u
ℓ
ν
ℓ
spectra with a model based on soft-gluon resummation and an analytic time-like QCD coupling, we obtain
where the first and the second error refer to experimental and theoretical error, respectively. This model successfully describes
the accurate experimental data in beauty fragmentation, which has similar soft-gluon effects. The |V
ub
| value is obtained from the available measured semileptonic branching fractions in limited regions of the phase space. The
distributions in the lepton energy E
ℓ
, the hadron invariant mass m
X
, the light-cone momentum
, together with the double distributions in (m
X
,q
2) and (E
ℓ
,s
hmax ), are used to select the phase-space regions. q
2 is the dilepton squared momentum and s
hmax is the maximal m
X
2 at fixed q
2 and E
ℓ
. The |V
ub
| value obtained is in complete agreement with the value coming from exclusive B decays and from an over-all fit to the standard model parameters. We show that the slight disagreement (up to +2σ) with respect to previous inclusive measurements is not related to different choices for the b (and c) masses, but to a different modeling of the threshold (Sudakov) region. 相似文献
14.
Xinman Chen Hong Zhou Guangheng Wu Dinghua Bao 《Applied Physics A: Materials Science & Processing》2011,104(1):477-481
A heterojunction structure of p-NiO/n-Mg0.6Zn0.4O with an aim to tuning or improving the resistive switching properties was fabricated on Pt/TiO2/SiO2/Si substrates by the sol-gel spin-coating technique. The Pt/NiO/Mg0.6Zn0.4O/Pt heterojunction thin-film device shows excellent resistive switching properties, such as a reduced threshold current of
1 μA for device initiation, a small dispersion of reset voltage ranging from 0.54 to 0.62 V, long retention time and a high
resistance ratio of high-resistance state to low-resistance state about six orders of magnitude. These results indicate that
the resistive switching properties can be greatly improved by constructing the p-NiO/n-Mg0.6Zn0.4O heterojunction for nonvolatile memory applications. The physical mechanism responsible for colossal resistive switching
properties of the heterojunction was analyzed based on interfacial defect effect and formation and rapture of conductive filaments. 相似文献
15.
V. Cirigliano H. Neufeld H. Pichl 《The European Physical Journal C - Particles and Fields》2004,35(1):53-65
We present a detailed numerical study of the Ke3 decays to
in chiral perturbation theory with virtual photons and leptons. We describe the extraction of the CKM matrix element |Vus| from the experimental Ke3 decay parameters. We propose a consistency check of the K + e3 and K0e3 data that is largely insensitive to the dominating theoretical uncertainties, in particular the contributions of
. Our analysis is highly relevant in view of the recent high statistics measurement of the K + e3 branching ratio by E865 at Brookhaven which does not indicate any significant deviation from CKM unitarity but rather a discrepancy with the present K0e3 data.Received: 22 January 2004, Published online: 30 April 2004Work supported in part by IHP-RTN, Contract No. HPRN-CT2002-00311 (EURIDICE) and by Acciones Integradas, Project No. 19/2003 (Austria), HU2002-0044 (MCYT, Spain) 相似文献
16.
F. Finkel D. Gómez-Ullate A. González-López M.A. Rodríguez R. Zhdanov 《Communications in Mathematical Physics》2003,233(2):191-209
The B
N
hyperbolic Sutherland spin model is expressed in terms of a suitable set of commuting Dunkl operators. This fact is exploited
to derive a complete family of commuting integrals of motion of the model, thus establishing its integrability. The Dunkl
operators are shown to possess a common flag of invariant finite-dimensional linear spaces of smooth scalar functions. This
implies that the Hamiltonian of the model preserves a corresponding flag of smooth spin functions. The discrete spectrum of
the restriction of the Hamiltonian to this spin flag is explicitly computed by triangularization. The integrability of the
hyperbolic Sutherland spin chain of B
N
type associated with the dynamical model is proved using Polychronakos's ``freezing trick'.
Received: 14 February 2002 / Accepted: 19 June 2002 Published online: 10 December 2002
RID="*"
ID="*" Corresponding author. E-mail: artemio@fis.ucm.es
RID="**"
ID="**" On leave of absence from Institute of Mathematics, 3 Tereschenkivska St., 01601 Kyiv-4 Ukraine
Communicated by L. Takhtajan 相似文献
17.
A. K. Panchal D. K. Rai Meril Mathew C. S. Solanki 《Journal of nanoparticle research》2011,13(6):2469-2473
40 alternate a-Si/SiN
x
multilayer are incorporated as an absorber layer in a p–i–n solar cell. The device is fabricated using hot-wire chemical
vapor deposition (HWCVD) technique. The structure of the multilayer film is examined by high resolution transmission electron
microscopy (HR-TEM) which shows distinct formation of alternate a-Si and SiN
x
layers. The a-Si and SiN
x
layers have thickness of ~3.5 and 4 nm, respectively. The photoluminescence (PL) of multilayer film shows bandgap energy
of ~2.52 eV, is larger than that of the c-Si and a-Si. Dark and illuminated current–voltage (I–V) characterization of the ML films shows that these ML are photosensitive. In the present work, it is seen that the p–i–n
structure with i-layer as ML quantum well (QW) structures show photovoltaic effect with relatively high open-circuit voltage
(V
OC). The increment of bandgap energy in PL and high V
OC of the device is attributed to the quantum confinement effect (QCE). 相似文献
18.
Representations of the sℓq(2) algebra are constructed in the space of polynomials of real (complex) variable for qN=1. The spin addition rule based on eigenvalues of Casimir operator is illustrated on few simplest cases and conjecture for general case is formulated. 相似文献
19.
An ensemble of figures required for the analysis of the atomic-vacancy ordering in nonstoichiometric compounds M
2
X
y
(M
2
X
y
▭1 − y
) with an L′3 hexagonal structure has been determined by the order-parameter functional method. It has been demonstrated reasoning from
the crystal lattice geometry that, in order to describe M
2
X
y
compounds with an L′3 structure, it is necessary to use the basis cluster in the form of a trigonal prism consisting of six sites of the nonmetal
lattice with a metal atom at the center. The overlapping figures that, together with the basis cluster, form a sequence of
special figures uniquely describing the L′3 structure have been found. The equilibrium conditions for disorder-order transformations in nonstoichiometric compounds
M
2
X
y
have been determined in the general form. 相似文献
20.
S.N.M. Ruijsenaars 《Communications in Mathematical Physics》2003,243(3):389-412
In previous work we introduced and studied a function
that generalizes the hypergeometric function. In this paper we focus on a similarity-transformed function
, with parameters 4 related to the couplings c4 by a shift depending on a
+
, a
–
. We show that the -function is invariant under all maps w(), with w in the Weyl group of type D
4
. Choosing a
+
, a
–
positive and
real, we obtain detailed information on the |Re
v| asymptotics of the -function. In particular, we explicitly determine the leading asymptotics in terms of plane waves and the c-function that implements the similarity R. 相似文献