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41.
42.
Uri Avraham 《Israel Journal of Mathematics》1981,39(1-2):167-176
We give some consistency results on the existence of uncountable free sets for nowhere-dense set mappings. For example, we
prove that it is relatively consistent with ZFC and Martin’s Axiom that any nowhere-dense set mapping defined on the reals
has an uncountable free set. 相似文献
43.
Avraham A. Melkman 《Israel Journal of Mathematics》1974,19(4):369-381
We consider interpolation of Hermite data by splines of degreen withk given knots, satisfying boundary conditions which may involve derivatives at both end points (e.g., a periodicity condition). It is shown that, for a certain class of boundary conditions, a necessary and sufficient condition for the existence of a unique solution is that the data points and knots interlace properly and that there does not exist a polynomial solution of degreen?k. The method of proof is to show that any spline interpolating zero data vanishes identically, rather than the usual determinantal approach. 相似文献
44.
We have found strong supporting evidence for the helical structures of single-stranded nucleic acids by stretching individual molecules of polyadenylic acid [poly(A)] and polycytidylic acid [poly(C)]. Analyzing the force versus extension data using a two-state elastic model in which random-coil domains alternate with rigid helical domains allows one to extract the thermodynamic and structural properties. In addition, it also yields moderate to low cooperativity of the helix-coil transition for poly(A) and poly(C), respectively. 相似文献
45.
Avraham Gal 《Few-Body Systems》2009,45(2-4):105-109
It takes two nucleons to bind a Λ hyperon, and perhaps as many as three nucleons to bind two Λ hyperons. Here I review few-body calculations which consider the onset of binding in multi-strange hypernuclei, including ${\Xi}$ hyperons once the free-space strong-interaction conversion ${\Xi N \to \Lambda \Lambda}$ becomes Pauli forbidden in Λ-abundant matter. Quasibound states of ${\overline {K}}$ mesons in few-nucleon systems are also briefly discussed. 相似文献
46.
In the foundation of quantum mechanics, the spatial dimensions of electron wavepacket are understood only in terms of an expectation value – the probability distribution of the particle location. One can still inquire how the quantum electron wavepacket size affects a physical process. Here we address the fundamental physics problem of particle–wave duality and the measurability of a free electron quantum wavepacket. Our analysis of stimulated radiative interaction of an electron wavepacket, accompanied by numerical computations, reveals two limits. In the quantum regime of long wavepacket size relative to radiation wavelength, one obtains only quantum-recoil multiphoton sidebands in the electron energy spectrum. In the opposite regime, the wavepacket interaction approaches the limit of classical point-particle acceleration. The wavepacket features can be revealed in experiments carried out in the intermediate regime of wavepacket size commensurate with the radiation wavelength. 相似文献
47.
Avraham M Steinberg 《Journal of Mathematical Analysis and Applications》1973,44(2):405-413
Given a single loop nonlinear control system. The problem of constructing a dither signal in order to obtain a desired equivalent nonlinearity is considered. It is assumed that the nonlinearity may be described by a kth order polynomial. For this case it is shown that in general k different levels for the dither signal are necessary. 相似文献
48.
Avraham Gover 《Optics Communications》1983,45(4):281-284
Stimulated Compton-Raman scattering and free electron lasers are formulated as parametric (four-photon) or three-wave interaction processes. Manley-Rowe relations and depletable pump equations are derived for both free electron lasers and optical klystron schemes. A process of backward wave oscillation is predicted when a pump radiation field is back scattered off a codirectionally propagating e beam with frequency down conversion. A practicable experiment in the optical regime is proposed to demonstrate this effect. 相似文献
49.
Michael Shandalov Avraham Rozenblat Nir Kedem Ronit Popovitz‐Biro Yuval Golan 《Surface and interface analysis : SIA》2008,40(5):939-943
The microstructure and composition of the interfacial layer between chemically deposited PbSe and GaAs substrates were studied using high‐resolution transmission electron microscopy (HRTEM), Auger electron spectroscopy (AES), x‐ray photoelectron spectroscopy (XPS) and energy‐filtered TEM. The thickness of the interfacial layer varied significantly from direct contact of the film with the substrate to 5 nm in the thickest regions. The results established the presence of a discontinuous, amorphous intermediate layer of Ga2O3 at the PbSe/GaAs interface. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
50.
In recent years several researchers suggested cost estimation models that consider limited capacity. These researchers ignored the stochastic nature of the shop floor. This paper presents a cost estimation model that takes into account the stochastic environment. It is based on marginal analysis – the difference between the total cost without the new order and the total cost with the new order. The proposed model is based on the integration of simulation and optimization. Data generated by the simulation is inserted into the optimization procedure that finds good feasible solutions quickly. A significant advantage of the proposed stochastic cost estimation over an existing deterministic approach is shown. A computational study is performed to test different factors affecting the proposed model. 相似文献