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1.
Hans J. Fahr 《Foundations of Physics Letters》2006,19(5):423-440
According to ideas of Mach, Whitrow, Dirac, or Hoyle, inertial masses of particles should not be a genuine, predetermined
quantity; rather they should represent a relational quantity which by its value somehow reflects the deposition and constellation
of all other objects in their cosmic environment. In this paper we want to pick up suggestions given by Thirring and by Hoyle
of how, due to requirements of the equivalence of rotations and of general relativistic conformal scale invariance, the particle
masses of cosmic objects should vary with the cosmic length scale. We study cosmological consequences of comoving cosmic masses
which co-evolve by mass with the expansion of the universe. The vanishing of the covariant divergence of the cosmic energy-momentum
tensor under the new prerequisite that matter density only falls off with the reciproke of the squared cosmic scale S(t) then leads to the astonishing result that cosmic pressuredoes not fall off adiabatically but rather falls off in a quasi-isothermal
behaviour, varying with S(t) as matter density does. Hence, as a new cosmological fact, it arises that, even in the late phases of cosmic expansion,
pressure cannot be neglected what concerns its gravitational action on the cosmic dynamics. We then show that under these
conditions the cosmological equations can, however, only be solved if, in addition to matter, also pressure and energy density
of the cosmic vacuum are included in the calculation. An unaccelerated expansion with a Hubble parameter falling off with
S(t)−1 is obtained for a vacuum energy density decay according to S(t)−2 with a well-tuned proportion of matter and vacuum pressures. As it appears from these results, a universe with particle masses
increasing with the cosmic sale S(t) is in fact physically conceivable in an energetically consistent manner, if vacuum energy at the expansion of the universe
is converted into mass density of real matter with no net energy loss occuring. This universe in addition also happens to
be an economical one which has and keeps a vanishing total energy. 相似文献
2.
Many rate constants, particularly for radical-radical reactions, are determined in systems exhibiting complex kinetics. Parameters often comprise several species concentrations, absorption cross sections, and rate constants. They cannot be obtained from an exact analytic expression, and therefore, must be solved iteratively through an efficient numerical differential equation solver. We examine here the reaction kinetics of the CH3 and the C2H3 mixed-radical system, generated by excimer laser photolysis of methyl vinyl ketone (MVK) at 193.3 nm. As a model, a detailed error analysis for determination of the cross-radical reaction rate constant, the initial CH3 and C2H3 radical concentrations are performed using a least-squares modeling program (Acufit). The least-squares program, an assumed mechanism, a detailed set of signal-averaged data, are viewed as the measuring “instrument.” The output of the “instrument” consists of a “signal” that is fit to the data using the least-squares criterion. This gives estimated parameters that are examined with respect to random as well as systematic errors. The biases due to uncertainties of each known parameter and combined uncertainties on the measured parameters are assessed. © 1994 John Wiley & Sons, Inc. 1 This article is a US Government work and, as such, is in the public domain in the United States of America. 相似文献
3.
Mohammad Nasser H. EL-Sherbiny Gamal M. Hammad Ali A. Askar Ahmed A. El- Nour Salwa A. Abou 《Cellulose (London, England)》2022,29(3):1791-1805
Cellulose - Antibacterial coatings based on bacterial cellulose (BC) have been widely used in many fields including food packaging and wound dressing. In this study, we aimed to synthesis of... 相似文献
4.
5.
A method is presented for obtaining periodic solutions to forced oscillations of non-linear systems governed by equations of the form uss?uyy?εf(u,u,y,uyy…,s) = 0. The method is presented by application to the equation uss?uyy?εu2yuyy= 0 which governs the vibrations of a soil layer that is free on the top surface and is forced harmonically at the bedrock. It is shown that unlike the ODE case (Duffing equation), the PDE requires an infinite number of periodicity conditions to correctly characterize the resonant region and these conditions lead to an infinite number of branches in the dispersion spectrum. Calculations indicate that these branches tend to an envelope curve. The uniform approach presented by Millmann and Keller is discussed in order to determine in what sense it can be viewed as an effective approximation for the fundamental mode. 相似文献
6.
7.
Egon Fahr 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》1973,85(4):179-179
8.
The paper derives the relevant non-linear integro-differential evolution equation by the method due to Collins expanding on a procedure by Keller. The quadratically non-linear case is not a trivial variation over the cubically non-linear case that was presented in preceding papers. As expected a different scaling and ordering of terms is needed and the first order perturbation solution provides no information on resonance. Nevertheless, although obtained by much longer calculations, the final equation for the present case is of identical form, with differences only in numerical coefficients, with the cubic case that was presented and solved earlier. 相似文献
9.
The phase transition during chemical lithium insertion into α-MoO3 was investigated by chemical analysis, X-ray diffraction (XRD) and electrochemical characterisation. The samples have been
prepared by reaction of various amounts of water-free lithium iodide with fine-particulate orthorhombic molybdenum trioxide
in n-hexane (non-aqueous media), which yielded materials with different Li/Mo ratio. XRD investigations of these materials proved
that the crystal structure of the layered α-MoO3 has been changed after the chemical lithiation. The phase transition ranged from 0.25 < x < 0.5 in Li
x
MoO3 upon chemical lithium insertion into α-MoO3. The XRD lines of lithium inserted phase Li
x
MoO3 grew at the expense of the XRD lines of the pristine α-MoO3 as lithium ions were chemically inserted until the disappearance of lines related to α-MoO3. The electrochemical performance of the lithiated samples is improved in comparison with the starting material (non-lithiated
α-MoO3). 相似文献
10.
Thin film tandem solar cells made of amorphous and microcrystalline silicon provide renewable energy at the benefit of low material consumption. As a drawback, these materials do not posses the high carrier mobilities of their crystalline counterpart which limits the feasible material thickness. For maintaining the light absorption as high as possible, photon management is required. Here we show that metallic nanodiscs that sustain localized plasmon polaritons can increase the efficiency of such solar cells if they are incorporated into the dielectric intermediate reflector separating the top and the bottom cell. We provide quantitative estimates for the possible absorption enhancement of optimized bi-periodic nanodiscs that are feasible for fabrication. Emphasis is also put on discussing the impact of obliquely incident sun light on the solar cell performance. 相似文献