共查询到20条相似文献,搜索用时 31 毫秒
1.
Let an external current, whose support is confined to the space-like slab |x
0| < T in two-dimensional spacetime, build up a localized charge density which vanishes for times |x
0| > T. We show that the zero mass Dirac quantum field reacts to this current by a c-number shift of the fermion number, i.e. Q
out=Q
in+Q, with
, where q(x
0) denotes the total external charge. For the shift of the axial charge we obtain an extension of existing results. 相似文献
2.
J. P. Wesley 《Foundations of Physics Letters》1992,5(6):597-604
The Weber potential energy U for charges q and q' separated by the distance R is U = (qq'/R)[1 – (dR/dt)2/2c2]. If this potential arises from a finite velocity c of energy transfer Q', where the retarded rate of transfer from q' to q is dQ(t-R/c)/dt = Q'[1 – (dR/dt)/c] and where the advanced rate from q to q' is dQ(t+R/c)/dt = Q'[1 + (dR/dt)/c], then the resultant time-average root-mean-square action is given by
. Identifying Q' with the Coulomb potential energy qq'/R, the Weber potential is obtained. Using the same argument, Newtonian gravitation yields a corresponding Weber potential energy, qq'/R being replaced by ( - Gmm'/R). 相似文献
3.
Dr. I. M. Templeton P. T. Coleridge L. -F. Chollet 《Zeitschrift für Physik B Condensed Matter》1969,9(1-2):21-22
We have used the de Haas-van Alphen (dHvA) effect to study the relaxation times of “neck” and “belly” electrons in copper
containing a range of dilute heterovalent and transition-metal solutes. The scattering (Dingle) temperaturex is derived from the variation of signal amplitude with magnetic field at a fixed temperature. Values ofx are believed accurate to within 0.1°K in a range ofx
N(neck) from ≃0.4°K to ≃6°K andx
B(belly) from ≃0.2°K to ≃3°K. Our results may be summarized as follows:Heterovalent solutes (Zn, Cd, Al; up to 0.1 at. %)
.Transition-metal solutes (Ni, Co, Fe, Mn, Cr; up to 0.05 at.-%)
.
An anomalous dependence of dHvA amplitude on magnetic field has been observed for belly oscillations in several very dilute
Cu Cr alloys. This anomaly is both concentration and temperature-sensitive, and is probably related to the Kondo effect. 相似文献
4.
5.
6.
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
7.
Stan Gudder 《Foundations of Physics》1999,29(6):877-897
This article begins with a review of the framework of fuzzy probability theory. The basic structure is given by the -effect algebra of effects (fuzzy events)
and the set of probability measures
on a measurable space
. An observable
is defined, where
is the value space of X. It is noted that there exists a one-to-one correspondence between states on
and elements of
and between observables
and -morphisms from
to
. Various combinations of observables are discussed. These include compositions, products, direct products, and mixtures. Fuzzy stochastic processes are introduced and an application to quantum dynamics is considered. Quantum effects are characterized from among a more general class of effects. An alternative definition of a statistical map
is given and it is shown that any statistical map has a unique extension to a statistical operator. Finally, various combinations of statistical maps are discussed and their relationships to the corresponding combinations of observables are derived. 相似文献
8.
Humic acids (HA) are complex, dark, paramagnetic biopolymers, ubiquitus in the soil and aquatic ecosystems. Due to their peculiar properties (multifluorophore system capable of excitation energy transfer, continuous featureless absorption over a wide spectral range, and paramagnetism), HA play an important role as an efficient target for UV solar radiation, O2, and O3—detrimental environmental factors which affect the Earth's biosphere. Photooxidation of HA causes changes in the absorption and luminescence properties of HA which may be of significant importance for environmental photophysics and photochemistry. We have studied effects of UV irradiation on the degradation of several commercial HA (Fluka, Merck, and Serva). Aqueous, aerated alkaline solutions of HA (0.1–0.4 g/L in 0.006–0.1 M Na2CO3) were irradiated with an electrodeless Hg (254-nm) lamp in a flow system during several hours. After different times of irradiation, solutions were assayed by means of fluorescence (Fl), absorption (UV–Vis), and chemiluminescence (CL) spectroscopy. The data obtained indicate that the free radical-mediated degradative photooxidation of HA macromolecules is accompanied by a very weak, long-lived chemiluminescence (340–800 nm), a gradual decrease in absorbancy with characteristic changes in color coefficients Q
4/6, Q
2.7/6.0, and Q
2.7/4.0, and an increase in the intensity of Fl emission (340- to 560-nm) and excitation (250- to 400-nm) spectra. Processes undergoing these changes are intrinsically associated with the generation of excited states and reactive oxygen species
. These processes are expected to play a vital role in the natural environment, e.g., HA-photosensitized decomposition of xenobiotics and solar energy transfer in symbiotic hydrobionts. 相似文献
9.
A. P. Fordy A. G. Reyman M. A. Semenov-Tian-Shansky 《Letters in Mathematical Physics》1989,17(1):25-29
The formalism of classical r-matrices is used to construct families of compatible Poisson brackets for some nonlinear integrable systems connected with Virasoro algebras. We recover the coupled KdV [1] and Harry Dym [2] systems associated with the auxiliary linear problem
10.
G. Z. Tu 《Letters in Mathematical Physics》1980,4(4):347-355
Let $$\begin{gathered} u^* = u + \in \eta (x,{\text{ }}t,{\text{ }}u), \hfill \\ \hfill \\ \hfill \\ x^* = x + \in \xi (x, t, u{\text{),}} \hfill \\ \hfill \\ \hfill \\ {\text{t}}^{\text{*}} = {\text{ }}t + \in \tau {\text{(}}x,{\text{ }}t,{\text{ }}u), \hfill \\ \end{gathered}$$ be an infinitesimal invariant transformation of the evolution equation u t =H(x,t,u,?u/?x,...,? n :u/?x n . In this paper we give an explicit expression for \(\eta ^{X^i }\) in the ‘determining equation’ $$\eta ^T = \sum\limits_{i = 1}^n {{\text{ }}\eta ^{X^i } {\text{ }}\frac{{\partial H}}{{\partial u_i }} + \eta \frac{{\partial H}}{{\partial u_{} }} + \xi \frac{{\partial H}}{{\partial x}} + \tau } \frac{{\partial H}}{{\partial t}},$$ where u i =? i u/?x i . By using this expression we derive a set of equations with η, ξ, τ as unknown functions and discuss in detail the cases of heat and KdV equations. 相似文献
11.
The phenomenon of the diffusion of proton and deuteron in a single crystal of magnesium aluminate spinel was studied by infrared
absorption. The chemical diffusion coefficient of proton was determined by the relaxation time of the absorption intensity
upon the substitution of deuteron with proton. The temperature dependence of the chemical diffusion coefficient of proton
for was expressed as . The chemical diffusion coefficient of proton was found to be independent of the composition of spinel and of the atmosphere.
Paper presented at the 11th Euro Conference on the Science and Technology of Ionics, Batz-sur-Mer, Sept. 9–15 2007. 相似文献
12.
C. Fronsdal 《Letters in Mathematical Physics》1991,22(3):225-228
The irreducible R-matrices associated with the quantum Liouville and sine-Gordon equations were classified by the su(2) index l, 2l integer. We find that the associated quantum field theories must have the following equal time operator product expansions in the lattice approximation
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