共查询到20条相似文献,搜索用时 15 毫秒
1.
Stanford Goldman 《Foundations of Physics》1982,12(9):907-917
This is a further development of the author's paper A Unified Theory of Biology and Physics. It is found that male and female in biology, as well as particle and antiparticle in physics, are analogues of symmetrical sideband pairs in communication theory. This gives a new point of view from which to investigate the significance and characteristics of these different paired entities.These findings are intimately related to the fact that there are two transform domains of representation of entities in all the cases involved. They are the somatic and the genetic domains in biology, the configuration domain and the domain of conserved observables in physics, and the time and frequency domains in communication. 相似文献
2.
The object of the present paper is first to study the role of maximum-entropy principle based on Shannon's entropy in generating stable distribution in statistics and characterizing stable thermal equilibrium state in thermodynamics. The second is to show the nonuniqueness of Shannon's entropy in the study of the stable distribution in statistics and stable equilibrium state in thermodynamics. 相似文献
3.
A technique combining image processing and laser interferometry for visualizing and detecting the deformation of transparent cylindrical and spherical sample is proposed. This deformation includes geometric deformation such as volume transition in profilometry and physical deformation such as refractive index change in tomography. Phase contour lines are used for quantitative analysis and graphical representation of the deformation. This method allows us to visually detect the spatial variation of the deformation field and to evaluate the test quality such as misalignment of optical system. A theoretical analysis using phase contour map to characterize the deformation field is described in detail. A method using phase contour map to qualify the interferometric test is proposed. Analysis of test examples is carried out. Suggestions on using phase contour line method to ameliorate test system design are finally discussed. 相似文献
4.
We show that good approximations to the exact equivalent local potential (ELP) and damping factor of a nonlocal Perey-Buck potential can be calculated in the partial wave WKB approximation of Horiuchi. The exact ELP and damping factor are obtained by means of a method previously given by one of us. We also confirm that an approximate ELP proposed by Bauhoff et al. is of comparable accuracy as the Horiuchi approximation. Thesel-dependent ELP's exhibit reduced attraction in the interior and provide a test for higher order WKB approximations. We subsequently obtain an equivalent velocity dependent potential (EVDP) which is even exactly wave function equivalent to the original nonlocal potential. This almost local potential, unlike the trivial equivalent local potential, is smooth and well-behaved and is therefore particularly useful in nuclear reactions where the off-shell behaviour of the potential is important. 相似文献
5.
Muonic and pionic X-rays of the L- and M-series in C and O have been measured with a Si(Li) detector in the energy range between 7 keV and 60 keV. The target consisted of mylar (C5H4O2). Energies and intensities of 21 transitions have been determined. The strong interaction shift of the pionic 2p level in O was measured and found to be +4.1 ±2.3 eV. The measured width of this level is 11±6 eV. The measured yields have been compared with cascade calculations. 相似文献
6.
While there is a range of colours found in plants the predominant colour is green. Pigments in plants have several roles e.g. photosynthesis and signalling. If colour is to be used as a signal then it must stand out from green. However, one should be aware that there are also coloured compounds where we have not yet fully investigated the role of colour in their functions—they may have roles in, for example, defence or heat exchange.In this paper, we will describe the basic chemistry of the major pigments found in plants and especially floral pigments. We will then discuss their locations in parts of the flower (such as sepals, petals, pollen and nectar), the cells in which they are found and their sub-cellular locations.Floral pigments have a large role to play in pollination of flowers by animals. They can and are modified in many ways during the development of flowers in nature, for example, at emergence and post-pollination. There are a range of biochemical mechanisms of colour change both within flowers and in isolated pigments. Some of the factors influencing colour are temperature, co-pigments, pH, metals, sugars, anthocyanin stacking and cell shape.There is a renewed interest in analysing floral pigments and how they are modified partly because of advances in recombinant DNA technologies, but also because of pollinators and their significance to biodiversity and for evolutionary studies. There is continued strong interest from the horticultural industry for the introduction of new colours e.g. the blue rose and for the exploitation of natural dyes. Funding in this area may impact future research in a potentially beneficial way but it must not deflect us from science-based conservation. 相似文献
7.
8.
Jeroen van Dongen 《Physics in Perspective (PIP)》2012,14(2):126-177
Albert Einstein accepted a ??special?? visiting professorship at the University of Leiden in the Netherlands in February 1920. Although his appointment should have been a mere formality, it took until October of that year before Einstein could occupy his special chair. Why the delay? The explanation involves a case of mistaken identity with Carl Einstein, Dadaist art, and a particular Dutch fear of revolutions. But what revolutions was one afraid of? The story of Einstein??s Leiden chair throws new light on the reception of relativity and its creator in the Netherlands and in Germany. 相似文献
9.
Sergio Doplicher 《Foundations of Physics》2010,40(7):719-732
It was shown in the early seventies that, in Local Quantum Theory (that is the most general formulation of Quantum Field Theory,
if we leave out only the unknown scenario of Quantum Gravity) the notion of Statistics can be grounded solely on the local
observable quantities (without assuming neither the commutation relations nor even the existence of unobservable charged field
operators); one finds that only the well known (para)statistics of Bose/Fermi type are allowed by the key principle of local
commutativity of observables. In this frame it was possible to formulate and prove the Spin and Statistics Theorem purely
on the basis of First Principles. 相似文献
10.
We present a systematic study of the effect of methyl substitution on iso- and alloxazines in acetonitrile solutions. Substitution patterns have profound effects on both spectral and photophysical properties, with fluorescence quantum yields varying by more than an order of magnitude. TD-DFT calculation were used for the first time to correlate electronic structure changes with the substitution patterns, with good agreement between calculated and theoretical band positions and oscillator strengths. Both n-pi* and pi-pi* states in these compounds are predicted, with the oscillator strengths indicating that only the pi-pi* states should be observable in the absorption spectra. Substitution patterns are shown to be responsible for energy order inversion between these states. 相似文献
11.
N. V. Lyanguzov V. E. Kaidashev V. B. Shirokov E. M. Kaidashev 《Technical Physics》2012,57(10):1411-1416
Ag and Au nanoparticles are obtained by magnetron sputtering and pulsed laser deposition under different conditions, and the features of their absorption spectra associated with plasmon resonances are investigated. Optimal deposition conditions for obtaining small (5?C10 nm) silver nanoparticles with a high density of surface distribution include an increased argon pressure (2.5 × 10?2 Torr) and a low discharge voltage (100 V). Gold nanoparticle arrays obtained by pulsed laser deposition at a temperature of 200°C in vacuum are more uniformly distributed on the substrates than those deposited at room temperature in argon. It is shown that the maximum of the plasmon absorption shifts toward shorter wavelengths with a decrease in the equivalent thickness of metal films and depends not only on this thickness but also on the type of substrate, which is responsible for the morphology of nanoparticle arrays. 相似文献
12.
B C Moore S R Oldfield G J Dooley 《The Journal of the Acoustical Society of America》1989,85(2):820-836
The ability of subjects to detect and discriminate spectral peaks and notches in noise stimuli was determined for center frequencies fc of 1 and 8 kHz. The signals were delivered using an insert earphone designed to produce a flat frequency response at the eardrum for frequencies up to 14 kHz. In experiment I, subjects were required to distinguish a broadband reference noise with a flat spectrum from a noise with either a peak or a notch at fc. The threshold peak height or notch depth was determined as a function of bandwidth of the peak or notch (0.125, 0.25, or 0.5 times fc). Thresholds increased with decreasing bandwidth, particularly for the notches. In experiment II, subjects were required to detect an increase in the height of a spectral peak or a decrease in the depth of a notch as a function of bandwidth. Performance was worse for notches than for peaks, particularly at narrow bandwidths. For both experiments I and II, randomizing (roving) the overall level of the stimuli had little effect at 1 kHz, but tended to impair performance at 8 kHz, particularly for notches. Experiments III-VI measured thresholds for detecting changes in center frequency of sinusoids, bands of noise, and spectral peaks or notches in a broadband background. Thresholds were lowest for the sinusoids and highest for the peaks and notches. The width of the bands, peaks, or notches had only a small effect on thresholds. For the notches at 8 kHz, thresholds for detecting glides in center frequency were lower than thresholds for detecting a difference in center frequency between two steady sounds. Randomizing the overall level of the stimuli made frequency discrimination of the sinusoids worse, but had little or no effect for the noise stimuli. In all six experiments, performance was generally worse at 8 kHz than at 1 kHz. The results are discussed in terms of their implications for the detectability of spectral cues introduced by the pinnae. 相似文献
13.
国外超导材料技术研究政策和方向 总被引:1,自引:1,他引:0
超导材料技术是21世纪具有战略意义的高新技术,极具发展潜力和市场前景。世界各发达国家纷纷制定研发计划,给予高度重视和大力支持,加快超导材料技术的基础研究和产业化发展。主要从美国、日本、欧洲国家、韩国等国家的相关研发计划、政策以及主要科研机构的研发概况出发,阐明目前国外超导材料技术的研究政策和方向。 相似文献
14.
A. B. Fedotov O. S. Ilyasov N. I. Koroteev A. M. Zheltikov 《Il Nuovo Cimento D》1992,14(10):1003-1013
Summary The experimental results on four-wave Raman and hyper-Raman scattering in a laser-produced and electric-discharge plasma are
presented. It has been shown that in spectra of four-wave mixing processes resonances appear due to the Raman and hyper-Raman
scattering on atomic and ionic excited states. The temporal behaviour of the scattered-signal intensity has been found to
be connected with the population relaxation of atomic and ionic excited states. We have observed for the first time the resonance
in the spectrum of coherent hyper-Raman scattering in electric-discharge plasma associated with the electron transition between
the excited and autoionizing state of a copper atom.
Paper presented at the ?XI European CARS Workshop?, Florence, Italy, 23–25 March, 1992. 相似文献
15.
We present new second-order prolongation and restriction formulas which preserve the divergence and, in some cases, the curl of a discretized vector field. The formulas are suitable for adaptive and hierarchical mesh algorithms with a factor-of-2 linear resolution change. We examine both staggered and collocated discretizations for the vector field on two- and three-dimensional Cartesian grids. The new formulas can be used in combination with numerical schemes that require a divergence-free solution in some discrete sense, such as the constrained transport schemes of computational magnetohydrodynamics. We also obtain divergence-preserving interpolation functions which may be used for streamline or field line tracing. 相似文献
16.
《Nuclear Physics B》1996,477(3):855-877
The interpretation of exact results on the low-energy limit of 4D N = 2 supersymmetric Yang-Mills theory in the language of 1D integrable system of particles is discussed. The Riemann surfaces of the Seiberg-Witten theory are explicitly described as spectral curves of Lax operators. The case of the elliptic Calogero system, associated with the flow between N = 4 and N = 2 supersymmetric in 4D, is considered in some detail. Equations for the corresponding Riemann surfaces are written down rather explicitly for all the SU(n) groups. 相似文献
17.
V.?M.?Za?nullina V.?P.?Zhukov V.?N.?Krasil’nikov M.?Yu.?Yanchenko L.?Yu.?Buldakova E.?V.?Polyakov 《Physics of the Solid State》2010,52(2):271-280
The electronic structures of undoped anatase and anatase doped with carbon and vanadium have been calculated using the ab
initio tight-binding linear muffin-tin orbital (TB-LMTO) method in the LSDA + U approximation. It has been shown that the
doping of TiO2 leads to the formation of narrow bands of the C and Vimpurity states in the band gap. The calculations of the imaginary part
of the dielectric function have made it possible to estimate the intensity of the optical absorption. It has been established
that the doping with vanadium and carbon leads to optical absorption in the visible range and to an increase in the absorption
in the ultraviolet range up to 4 eV. This should result in an increase in the photocatalytic activity on the surface of the
doped anatase. The experimental determination of the photocatalytic activity of whiskers of the anatase doped with carbon
and vanadium in the reaction of hydroquinone oxidation has confirmed the increase in the activity of the doped materials under
exposure to ultraviolet, visible, and blue light. The phenomenon of dark catalysis in the anatase doped with carbon and vanadium
has been interpreted within the concept of low-energy electronic excitatio ns between the impurity levels of carbon. 相似文献
18.
Spectral and photosensitizing properties of bacteriochlorin a and its monomethyl and dimethyl esters
I. N. Nichiporovich T. N. Vadetskaya A. V. Vorobei N. D. Kochubeeva V. A. Kuz’mitskii 《Journal of Applied Spectroscopy》2006,73(1):107-114
We have carried out a comparative study of the photosensitizing activity of bacteriochlorin a (BCA) and its methylated derivatives:
monomethyl and dimethyl esters of BCA (BCA MME and BCA DME). We have shown that BCA and its derivatives are bound to the erythrocyte
membranes in monomolecular form, and upon photoexcitation in the region of their long-wavelength Qy absorption band, they sensitize oxidation of the major membrane components: proteins and lipids. We have established that
despite greater binding of the methylated BCA derivatives to the membranes, their specific activity in photosensitization
of peroxide oxidation of membrane lipids and membrane protein tryptophanyls is lower than for BCA. At the same time, BCA MME
and BCA DME sensitize oxidation of a larger number of SH groups in membrane proteins, which suggests methylated BCA is predominantly
localized in the erythrocyte membrane close to the protein sulfhydryl groups. We also show that the rate of erythrocyte photohemolysis
sensitized by BCA MME and BCA DME is significantly faster than for sensitization by BCA. This correlates with the lipophilicity
of BCA, BCA MME, and BCA DME, which is responsible for the ability of bacteriochlorins to bind to cell membranes and cells.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 1, pp. 98–105, January–February, 2006. 相似文献
19.
Mohammad Reza Kazemi Saeid Tahmasebi Francesco Buono Maria Longobardi 《Entropy (Basel, Switzerland)》2021,23(5)
Deng entropy and extropy are two measures useful in the Dempster–Shafer evidence theory (DST) to study uncertainty, following the idea that extropy is the dual concept of entropy. In this paper, we present their fractional versions named fractional Deng entropy and extropy and compare them to other measures in the framework of DST. Here, we study the maximum for both of them and give several examples. Finally, we analyze a problem of classification in pattern recognition in order to highlight the importance of these new measures. 相似文献
20.
A theoretical framework is presented to treat both imaging and diffraction experiments performed with point-focus and line-focus X-ray sources, with particular emphasis on two-dimensional and planar X-ray waveguides. In particular, point-projection and line-projection microscopy has been approached within the Huygens-Fresnel formalism; point-projection and line-projection diffraction, such as spatially-resolved Bragg/Laue diffraction of crystalline samples in a regime of dynamical scattering, has been treated both by means of the Huygens-Fresnel formalism and of the Takagi-Taupin dynamical theory. Both in point- and line- projection geometry, simply rotating the investigated crystalline samples, it is possible to switch from Fresnel self-imaging to Bragg/Laue diffraction conditions. This means to image, within the same experiment, either morphological features, with a sub-micrometric resolution, out of the exact diffraction condition, or the structure order on an atomic scale if placing the sample in diffraction. 相似文献