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991.
This paper extends a method for predicting rotational losses for laminated rotors of heteropolar magnetic bearings by using an eddy-current model to include the effect of magnetic hysteresis in the rotor material. It compares the modeling results to the experimental data that were used earlier to assess the loss model neglecting hysteresis. The correction to the total electromagnetic loss in the rotor due to the hysteresis is significant at rotational speeds below 6000 revolutions per minute (RPM), where the model including hysteresis effects provides much better agreement with existing experimental data. 相似文献
992.
V. M. Samoilov 《Inorganic Materials》2004,40(12):1271-1275
The effect of the nature of two-component fillers on the physical and mechanical properties of finegrained graphites was studied using highly oriented needle coke and nearly isotropic synthetic graphite as components of fillers. Each filler was prepared in the form of coarse (-120 µm) and fine (-10 µm) powders. Different mixtures of these components were used in producing graphite samples, which were then characterized by density, thermal expansion, compressive strength, and modulus of elasticity measurements. The results demonstrate that the thermal expansion, compressive strength, and modulus of elasticity of the graphites thus prepared depend on the microtexture, size, and shape of the filler particles.Translated from Neorganicheskie Materialy, Vol. 40, No. 12, 2004, pp. 1448–1454.Original Russian Text Copyright © 2004 by Samoilov. 相似文献
993.
E. N. Selivanov V. M. Chumarev R. I. Gulyaeva V. P. Mar'evich A. D. Vershinin A. A. Pankratov E. S. Korepanova 《Inorganic Materials》2004,40(8):845-850
The iron calcium oxysulfides Ca3Fe4S3O6 and CaFeSO are synthesized by reacting mixtures of CaO and FeS in an inert atmosphere. Their elemental compositions and lattice parameters are determined by x-ray microanalysis and x-ray diffraction. From the temperature-dependent lattice parameters of the oxysulfides (measured up to 1020 K), their thermal expansion coefficients are evaluated. 相似文献
994.
A. Yu. Zavrazhnov D. N. Turchen Zh. V. Dobrokhotova V. V. Volkov E. V. Makhonina V. S. Pervov 《Inorganic Materials》2004,40(2):107-114
The GaSe–Ga2Se3 system is studied by x-ray diffraction, electron microscopy, and differential scanning calorimetry. The results demonstrate that the nonadditivity of heat capacity observed near the eutectic composition after quenching is similar to the nonadditivity of properties in misfit layer compounds, which contain incommensurate structural components. The origin of this similarity is discussed in terms of the self-organization of interacting incommensurate elements in the melt and the formation of unstable suprastructural ensembles. 相似文献
995.
E. H. Boutyour H. Zahrouni M. Potier‐Ferry M. Boudi 《International journal for numerical methods in engineering》2004,60(12):1987-2012
The aim of this work is to develop a reliable and fast algorithm to compute bifurcation points and bifurcated branches. It is based upon the asymptotic numerical method (ANM) and Padé approximants. The bifurcation point is detected by analysing the poles of Padé approximants or by evaluating, along the computed solution branch, a bifurcation indicator well adapted to ANM. Several examples are presented to assess the effectiveness of the proposed method, that emanate from buckling problems of thin elastic shells. Especially problems involving large rotations are discussed. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
996.
H. Ji J. E. Dolbow 《International journal for numerical methods in engineering》2004,61(14):2508-2535
We consider a problem stemming from recent models of phase transitions in stimulus‐responsive hydrogels, wherein a sharp interface separates swelled and collapsed phases. Extended finite element methods that approximate the local solution with an enriched basis such that the mesh need not explicitly ‘fit’ the interface geometry are emphasized. Attention is focused on the weak enforcement of the normal configurational force balance and various options for evaluating the jump in the normal component of the solute flux at the interface. We show that as the reciprocal interfacial mobility vanishes, it plays the role of a penalty parameter enforcing a pure Dirichlet constraint, eventually triggering oscillations in the interfacial velocity. We also examine alternative formulations employing a Lagrange multiplier to enforce this constraint. It is shown that the most convenient choice of basis for the Lagrange multiplier results in oscillations in the multiplier field and a decrease in accuracy and rate of convergence in local error norms, suggesting a lack of stability in the discrete formulation. Under such conditions, neither the direct evaluation of the gradient of the approximation at the phase interface nor the interpretation of the Lagrange multiplier field provide a robust means to obtain the jump in the normal component of solute flux. Fortunately, the adaptation and use of local, domain‐integral methodologies considerably improves the flux evaluations. Several example problems are presented to compare and contrast the various techniques and methods. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
997.
Jürgen Schönbeçk 《NTM》2004,12(2):80-99
Thomas Fincke (January 6th, 1561–April 24th, 1656), born in Flensburg (Germany), was one of the very most important and significant scientists in Denmark during the
seventeenth century, a mathematician and astrologer and physician in the beginning of modern science, a representative of
humanism and an influentual academic organizer. He studied in Strasbourg (since 1577) and Padua (since 1583) and received
his M.D. in Basel (1587), he practised as a physician throughout his life (since 1587 or 1590) and became a professor at Copenhagen
(1591). But he was best known because of his Geometriae rotundi libri XIIII (1583), a famous book on plane and spherical trigonometry, based not on Euclid but on Petrus Ramus. In this influentual work,
in which Fincke introduced the terms tangent and secant and probable first noticed the Law of Tangents and the so-called Newton-Oppel-Mauduit-Simpson-Mollweide-Gauss-formula,
he showed himself to be „abreast of the mathematics of his time“.
相似文献
998.
In this paper we show that by the analysis of 2D images collected with a laboratory X-ray microdiffractometer it is possible to non-destructively evaluate the structure, the microstructure, and the preferred orientation of films. In particular, the structural analysis of Co/Au multilayers on Si(1 0 0) deposited at different Ar pressures are reported and discussed. 相似文献
999.
L. N. Dmitruk S. Kh. Batygov L. V. Moiseeva O. B. Petrova M. N. Brekhovskikh V. A. Fedorov 《Inorganic Materials》2007,43(7):793-796
We have studied the effect of In3+, Pb2+, Gd3+, and Cl (heavier ions) substitutions for Al3+, Ba2+, La3+, and F? on the crystallization stability and UV/IR optical properties of HBLAN fluorohafnatc glasses (HfF4-BaF2-LaF3-AlF3-NaF system). We obtained stable glasses containing InF3 and BaCl2 instead of AlF3 and BaF2, respectively, and offering increased IR transmission. The presence of CCl4 in the process atmosphere and the removal of oxygen-containing impurities via directional solidification are shown to have an advantageous effect on the optical quality of the glasses. The fluoride-chloride glasses are capable of accommodating about 1.5 times higher levels of rare-earth activators in comparison with their fluoride analogs. 相似文献
1000.
Sorin Manolache Petru Eles Zebo Peng 《International journal of parallel programming》2007,35(2):125-156
As feature sizes shrink, transient failures of on-chip network links become a critical problem. At the same time, many applications
require guarantees on both message arrival probability and response time. We address the problem of transient link failures
by means of temporally and spatially redundant transmission of messages, such that designer-imposed message arrival probabilities
are guaranteed. Response time minimisation is achieved by a heuristic that statically assigns multiple copies of each message
to network links, intelligently combining temporal and spatial redundancy. Concerns regarding energy consumption are addressed
in two ways. First, we reduce the total amount of transmitted messages, and, second, we minimise the application response
time such that the resulted time slack can be exploited for energy savings through voltage reduction. The advantages of the
proposed approach are guaranteed message arrival probability and guaranteed worst case application response time. 相似文献