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1.
The following hydrogen and oxygen concentration cells using the oxide protonic conductors,
\textCaZ\textr0.98\textI\textn0.02\textO3 - d {\text{CaZ}}{{\text{r}}_{0.98}}{\text{I}}{{\text{n}}_{0.02}}{{\text{O}}_{3 - \delta }} and
\textCaZ\textr0.9\textI\textn0.1\textO3 - d {\text{CaZ}}{{\text{r}}_{0.{9}}}{\text{I}}{{\text{n}}_{0.{1}}}{{\text{O}}_{{3} - \delta }} , as the solid electrolyte were constructed, and their polarization behavior was studied,
( \textreversible: - )\text Pt,\textH2 + \textH2\textO/\textCaZ\textr1 - y\textI\textny\textO3 - d( y = 0.02\text or 0.1 )/\textAr( + \textH2 + \textO2 ),\text Pt( + :\textirreversible ) \left( {{\text{reversible}}: - } \right){\text{ Pt}},{{\text{H}}_2}{ + }{{\text{H}}_2}{\text{O}}/{\text{CaZ}}{{\text{r}}_{1 - y}}{\text{I}}{{\text{n}}_y}{{\text{O}}_{3 - \delta }}\left( {y = 0.02{\text{ or }}0.1} \right)/{\text{Ar}}\left( { + {{\text{H}}_2} + {{\text{O}}_2}} \right),{\text{ Pt}}\left( { + :{\text{irreversible}}} \right) 相似文献
2.
Formation of gold(III) complexes with the synthetic antibiotic norfloxacin (NF) was investigated in aqueous solution at pH
4.0, 7.5 and 10.6, with the ligand in cationic, zwitterionic and anionic forms, respectively. UV-Visible spectroscopy, steady
state and time-resolved fluorometry were used to characterize the complexes. Binding sites, association constants and fluorescence
lifetimes of the complexes were obtained. Au3+ binding to zwitterionic NF produced a fluorescence decrease and a small red shift. Fluorescence changes as a function of
Au3+ concentration were fitted using a one-site binding model and the association constant was obtained,
Kbzw = 1.7 ×105 \textM1 K_b^{{zw}} = {1}.{7} \times {1}{0^{{5}}}\;{{\text{M}}^{{1}}} . The association of Au3+ with cationic NF was much weaker, the obtained binding constant being
Kbcat = 2.4 ×103 \textM1 K_b^{{cat}} = {2}.{4} \times {1}{0^{{3}}}\;{{\text{M}}^{{1}}} . The Au3+ binding site for these species involves the carboxyl group, in agreement with a much stronger association of the cation with
the carboxylate anion than with the neutral acid. Association of Au3+ with nonfluorescent anionic NF presented a clear evidence of two binding sites. The highest affinity site is the unprotonated
piperazinyl group with
Kbpip \geqslant 5 ×107 \textM - 1 K_b^{{pip}} \geqslant {5} \times {1}{0^{{7}}}\;{{\text{M}}^{{ - {1}}}} , and the low affinity site includes the carboxylate anion. The results point out to important pH dependent differences in
complex formation between transition metal ions and fluoroquinolones, leading to different binding sites and association constants
that change by several orders of magnitude. 相似文献
3.
The complex impedance of the Ag2ZnP2O7 compound has been investigated in the temperature range 419–557 K and in the frequency range 200 Hz–5 MHz. The Z′ and Z′ versus frequency plots are well fitted to an equivalent circuit model. Dielectric data were analyzed using complex electrical
modulus M* for the sample at various temperatures. The modulus plot can be characterized by full width at half-height or in terms of
a non-exponential decay function
f( \textt ) = exp( - \textt/t )b \phi \left( {\text{t}} \right) = \exp {\left( { - {\text{t}}/\tau } \right)^\beta } . The frequency dependence of the conductivity is interpreted in terms of Jonscher’s law:
s( w) = s\textdc + \textAwn \sigma \left( \omega \right) = {\sigma_{\text{dc}}} + {\text{A}}{\omega^n} . The conductivity σ
dc follows the Arrhenius relation. The near value of activation energies obtained from the analysis of M″, conductivity data, and equivalent circuit confirms that the transport is through ion hopping mechanism dominated by the
motion of the Ag+ ions in the structure of the investigated material. 相似文献
4.
Moments of the hadronic invariant mass and of the lepton energy spectra in semileptonic B decays have been determined with
the data recorded by the DELPHI detector at LEP. From measurements of the inclusive b-hadron semileptonic decays, and imposing constraints from other measurements on b- and c-quark masses, the first three moments of the lepton energy distribution and of the hadronic mass distribution, have been
used to determine parameters which enter into the extraction of |Vcb| from the measurement of the inclusive b-hadron semileptonic decay width. The values obtained in the kinetic scheme are:
and include corrections at order 1/mb3. Using these results, and present measurements of the inclusive semileptonic decay partial width of b-hadrons at LEP, an accurate determination of |Vcb| is obtained:
Received: 26 April 2005, Revised: 16 September 2005, Published online: 16 November 2005 相似文献
5.
A method for the determination of the noise spectral density in a high-temperature microwave SQUID operating in the hysteresis regime is developed. Under these conditions, the reflection coefficient serves as an output signal. It is shown that if a directional coupler used for extracting the reflected wave is placed as close to the SQUID loop as possible, the magnetometer can be designed as a microwave integrated circuit with a noise flux spectral density SF 1/2 < 10 - 5 F0 /\textHz\text0\text.5 ,\textwhere F\text0 S_\Phi ^{1/2} < 10^{ - 5} \Phi _0 /{\text{Hz}}^{{\text{0}}{\text{.5}}} ,{\text{where }}\Phi _{\text{0}} , is the magnetic flux quantum. 相似文献
6.
In order to improve the chemical stability of BaCeO3, Ti4+ was introduced into B site of BaCeO3 to modify the chemical stability. XRD test demonstrates that
\textBaC\texte0.6\textT\texti0.2\textY0.2\textO3 - d {\text{BaC}}{{\text{e}}_{0.6}}{\text{T}}{{\text{i}}_{0.2}}{{\text{Y}}_{0.2}}{{\text{O}}_{3 - \delta }} (BCTY) keeps its original pervoskite-type structure at a high doping level of 20%. After exposure in 94% N2 + 3% CO2 + 3% H2O at 700 °C for 10 h, BCTY exhibited adequate chemical stability while decomposition was found in
\textBaC\texte0.8\textY0.2\textO3 - d {\text{BaC}}{{\text{e}}_{0.8}}{{\text{Y}}_{0.2}}{{\text{O}}_{3 - \delta }} (BCY). Accordingly, the conductivity of BCTY reaches 0.0072 S/cm at 700 °C in humidified hydrogen which is a little lower
than BCY (0.0085). Besides, BCTY displayed better sintering characteristics than BCY at high temperatures and the relative
density reaches 96.4% and 94.8%, respectively. The two samples also exhibited similar thermal expansion behavior from 30 to
1,000 °C. A fuel cell with BCTY as electrolyte exhibited 244 mW/cm2 at 700 °C and the stable short-term performance further proved the stability of BCTY. 相似文献
7.
The conductivity of glasses in the
50\textP\text2 \textO\text5 - x\textV\text2 \textO\text5 - ( 50 - x )\textLi\text2 \textO50{\text{P}}_{\text{2}} {\text{O}}_{\text{5}} - x{\text{V}}_{\text{2}} {\text{O}}_{\text{5}} - \left( {50 - x} \right){\text{Li}}_{\text{2}} {\text{O}} system was studied as a function of temperature and composition. For all compositions, the conductivity variation as a function
of temperature followed an Arrhenius type relationship. Isothermal variation of conductivity as a function of composition
showed a minimum for a molar ratio x near 20. Probable mechanisms for decrease of conductivity with decrease of vanadium oxide concentration were explained. The
minimum in room temperature was attributed to increase of V4+/V5+ with decrease of vanadium oxide in specific concentrations of vanadium oxide. Activation energy increased with decrease of
V2O5 content. This behavior was attributed to increase of average spacing between vanadium ions. 相似文献
8.
M. B. Ivanov S. S. Manokhin D. A. Nechaenko Yu. R. Kolobov 《Russian Physics Journal》2011,54(7):749-755
Investigations of disperse nonmetallic inclusions in unalloyed alpha titanium VT1-0 have been performed by using transmission
electron (including scanning and high-resolution) microscopy. Characteristic electron energy losses spectroscopy has shown
that these inclusions are titanium carbide particles. It has been revealed that the disperse carbides are formed in the titanium
hcp matrix as a phase based on the fcc sublattice of titanium atoms. The inclusion–matrix orientation relationship corresponds
to the well-known Kurdyumov–Sachs and Nishiyama–Wassermann relationships
[ 2[`11] 0 ]\upalpha ||[ 011 ]\updelta \text and ( 000[`1] )\upalpha ||( 1[`1] 1 )\updelta {\left[ {2\overline {11} 0} \right]_{{\upalpha }}}\parallel {\left[ {011} \right]_{{\updelta }}}{\text{ and }}{\left( {000\overline 1 } \right)_{{\upalpha }}}\parallel {\left( {1\overline 1 1} \right)_{{\updelta }}} . 相似文献
9.
In a previous report (J. Fluoresc. 16, 153, 2006) we studied the chaotropiclly induced denaturation of Bovine Serum Albumin (BSA) using the fluorescence decay
kinetics at different stages in the denaturation of BSA by guanidinium hydrochloride (GuHCl). In this work, we gain a more
detailed insight into the BSA denaturation process by investigating the thermodynamics of the process. Structural changes
were monitored spectrophotometrically via the intrinsic protein fluorescence from tryptophan residues, and the extrinsic fluorescence
from 1,8-anilinonaphthalene sulphonate (ANS). ANS tends to locate in a variety of binding sites in BSA which are located in
different domains, and these can be selectively populated using different, 1:1 and 1:10 molar ratios of BSA to ANS. The data
from steady-state and time-resolved fluorescence spectroscopy were analyzed using thermodynamic two-state and three-state
models and the lifetime data clearly indicated the presence of an intermediate state during denaturation. A global analysis
using non-linear regression gave a
DGH2O,D0 = 6.7 \textkcal.\textmo\textl - 1 \Delta G_{{H_2}O,D}^0 = 6.7\;{\text{kcal}}.{\text{mo}}{{\text{l}}^{ - 1}} for the complete unfolding of the BSA-ANS complexes, and a
DGH2O,I0 = 0.9 \textkcal.\textmo\textl - 1 \Delta G_{{H_2}O,I}^0 = 0.9\;{\text{kcal}}.{\text{mo}}{{\text{l}}^{ - 1}} for the first step to the intermediate. Therefore, the unfolding energy of the intermediate, which appears mostly at intermediate
GuHCl concentrations (1.0 to 1.5 M), to the denatured state, is 5.8 kcal.mol−1. The lifetime analysis of the BSA-ANS complexes also shows clearly that there are differences in stability of the BSA domains,
with domain III unfolding first at low GuHCl concentrations (<1.5 M). 相似文献
10.
The temperature dependence of the electrical conductivity of the compound 2,4,4-trimethyl-4,5-dihydro-3H-benzo[b] [1,4] diazepin-1-ium tetrachlorocadmiate in the different phases follows the Arrhenius law. The imaginary part of
the permittivity constant is analyzed with the Cole–Cole formalism. In the temperature range 348–394 K, the activation energy
of conductivity obtained from complex permittivity in regions I and II are, respectively, 1.03 and 0.33 eV, and E
m (in regions I and II are, respectively, 0.97 and 0.36 eV) obtained from the modulus spectra is close, suggesting that the
ion transport is probably due to a hopping mechanism. The Kohlrausch–Williams–Watts function,
j(t) = exp( - ( \fractt\textKWW )b ) \varphi (t) = \exp \left( { - {{\left( {\frac{t}{{{\tau_{\text{KWW}}}}}} \right)}^\beta }} \right) , and the coupling model are utilized for analyzing electric modulus at various temperatures. The decreasing of β at 373 K is due to approaching the temperatures of change in the conduction mechanism of the sample. 相似文献
11.
S. G. Karshenboim 《Physics of Particles and Nuclei Letters》2009,6(6):450-454
Oscillations of neutral meson (K
0-$
\overline {K^0 }
$
\overline {K^0 }
, D
0-$
\overline {D^0 }
$
\overline {D^0 }
, and B
0-$
\overline {B^0 }
$
\overline {B^0 }
are extremely sensitive to the meson and antimeson energies at rest. This energy is determined as mc
2—with the corresponding inertial mass—and as the energy of gravitational interaction. Assuming that the CPT theorem is correct
for inertial masses and estimating the gravitational potential for which the largest contribution originates from the field
of the galaxy center, we obtain the estimate from experimental data on K
0-$
\overline {K^0 }
$
\overline {K^0 }
oscillations:
|