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111.
The aim of the paper is to fill the gap between the general theoretical formulation of the constitutive relations for plastic spin and practical applications for proper prediction of material behavior at finite plastic deformations and anisotropic hardening. An approximation to the representation of the general constitutive equation for plastic spin is considered and the pertinent substructure corotational rate is applied to formulate the relation for rigid-plastic material with kinematic hardening. The simple shear traction problem is analysed and the proposed model is verified with the experimental results of Swift. The merits of the present proposal vis-à-vis the existing theories are discussed. 相似文献
112.
113.
Z. A. Samoilenko V. D. Okunev S. J. Lewandowski P. Aleshkevych Yu. M. Nikolaenko E. I. Pushenko O. Abal’oshev P. Gierlowski A. N. Bondarchuk A. B. Glot 《Technical Physics》2013,58(8):1144-1151
A metastable hexagonal R-phase is revealed in polycrystalline In2O3-SrO samples, which has the form of a network made up of mesoscopic clusters (60–180 Å in size). The clusters arise from strontium-enriched regions near grain boundaries in the main cubic structure of indium oxide. It is shown that annealing in oxygen at T a ? 300°C saturates dangling bonds between the R-phase and the matrix and makes the system metastable. This state shows up in the presence of (i) solitary diffuse maxima from the R-phase imposed on Debye lines from the main phase in the X-ray diffraction pattern and (ii) the electron cyclotron resonance (ECR) line with g = 1.875. In addition, the sample in this state acquires a high resistivity (ρ ~ 106 Ω cm). Relaxation at T ? 300°C after annealing at T a > 300°C disrupts bonds between the strontium-enriched clusters of the R-phase and the indium oxide matrix. This causes spatial separation of the clusters, disruption of their coherent bonds with the matrix structure, and escape of excess oxygen from the sample along grain boundaries. As a result, a new stable state forms, which is characterized by (i) a series of diffuse maxima from the R-phase imposed on lines assigned to the main phase, (ii) the presence of the ECR line with g = 2 with the line with g = 1.875 retained, and (iii) the transition of the sample to a low-resistivity state (ρ ~ 100 Ω cm). 相似文献
114.
The analytical solution of laminar free convective heat transfer in an unlimited space from an isothermal horizontal ring with an adiabatic plug is presented. The results of theoretical considerations are presented as relation of the Nusselt and Rayleigh numbers: $$Nu_D = 1.151 \cdot (Ra_D )^{1/5} \cdot \Phi (\phi _0 )$$ \] where Φ(φ0) is a function of shape coefficient of the ring (φ0=d/D). The solution presented has been verified experimentally with rings of constant external diameter (D=0.06 [m]) and various internal diameters (d=0, 0.01, 0.02, 0.04 and 0.05 [m]). The fluid tested was glycerin. The theoretical predictions agree well with the experimental results. 相似文献
115.
116.
Adam Liwo Jarosław Pillardy Rajmund Kaźmierkiewicz Ryszard J. Wawak Małgorzata Groth Cezary Czaplewski Stanisaw Ołdziej Harold A. Scheraga 《Theoretical chemistry accounts》1999,101(1-3):16-20
A united-residue model of polypeptide chains developed in our laboratories with united side-chains and united peptide groups
as interaction sites is presented. The model is designed to work in continuous space; hence efficient global-optimization
methods can be applied. In this work, we adopted the distance-scaling method that is based on continuous deformation of the original
rugged energy hypersurface to obtain a smoothed surface. The method has been applied successfully to predict the structures
of simple motifs, such as the three-helix bundle structure of the 10-58 fragment of staphylococcal protein A in de novo folding
simulations and more complicated motifs in inverse-folding simulations.
Received: 24 April 1998 / Accepted: 4 August 1998 / Published online: 2 November 1998 相似文献
117.
We study the variational equations for solitons in noncommutative scalar field theories in an even number of spatial dimensions. We prove the existence of spherically symmetric solutions for a sufficiently large noncommutativity parameter θ and we prove the absence of spherically symmetric solutions for small θ. 相似文献
118.
V. D. Okunev N. N. Pafomov V. A. Isaev T. A. D’yachenko A. Klimov S. J. Lewandowski 《Physics of the Solid State》2002,44(1):157-161
This paper reports on new results of experimental investigations into the nature of the electrical resistivity ρ(T) ? const at T<T crit for YBaCuO and LaSrMnO dielectric films. The films are prepared by pulsed laser deposition and contain nanocrystalline clusters with metallic conductivity. Dependences of the electrical resistivity ρ(T) ? const are observed for the epitaxial films YBaCuO (T crit=10 K) with a tetragonal structure after exposure to KrF excimer laser radiation and for the as-prepared amorphous films LaSrMnO (T crit?160 K). The effect of interest (ρ(T) ? const) manifests itself in the case when the optical spectra of the studied samples contain portions attributed to absorption by free charge carriers. The inference is made that this effect can be associated with tunneling conduction in a system of quantum dots. 相似文献
119.
Aubert B Barate R Boutigny D Couderc F Karyotakis Y Lees JP Poireau V Tisserand V Zghiche A Grauges E Palano A Pappagallo M Pompili A Chen JC Qi ND Rong G Wang P Zhu YS Eigen G Ofte I Stugu B Abrams GS Battaglia M Breon AB Brown DN Button-Shafer J Cahn RN Charles E Day CT Gill MS Gritsan AV Groysman Y Jacobsen RG Kadel RW Kadyk J Kerth LT Kolomensky YG Kukartsev G Lynch G Mir LM Oddone PJ Orimoto TJ Pripstein M Roe NA Ronan MT Wenzel WA Barrett M Ford KE Harrison TJ Hart AJ Hawkes CM Morgan SE 《Physical review letters》2007,98(21):211804
We present a measurement of the partial branching fractions and mass spectra of the exclusive radiative penguin processes B-->Kpipigamma in the range m(Kpipi)<1.8 GeV/c(2). We reconstruct four final states: K(+)pi(-)pi(+)gamma, K(+)pi(-)pi(0)gamma, K(S)(0)pi(-)pi(+)gamma, and K(S)(0)pi(+)pi(0)gamma, where K(S)(0)-->pi(+)pi(-). Using 232 x 10(6) e(+)e(-)-->BB events recorded by the BABAR experiment at the SLAC PEP-II asymmetric-energy storage ring, we measure the branching fractions B(B(+)-->K(+)pi(-)pi(+)gamma)=[2.95+/-0.13(stat)+/-0.20(syst)] x 10(-5), B(B(0)-->K(+)pi(-)pi(0)gamma)=[4.07+/-0.22(stat)+/-0.31(syst)] x 10(-5), B(B(0)-->K(0)pi(+)pi(-)gamma)=[1.85+/-0.21(stat)+/-0.12(syst)] x 10(-5), and B(B(+)-->K(0)pi(+)pi(0)gamma)=[4.56+/-0.42(stat)+/-0.31(syst)] x 10(-5). 相似文献
120.
Experimental investigations of laminar free convection from horizontal isothermal surfaces screened by cylindrical vertical walls are presented. Screen diameters (D) were equal to the diameter of a heating plate while their heights (H) were varied. Results obtained for several heating fluxes and two different liquids indicate that depending on the (H/D) ratio of cylindrical screens, the heat flux transferred from the heating plate to the liquid varies. Three subranges of screening effect have been distinguished: primary inhibition, intensification and secondary inhibition. For primary inhibition, a theoretical model has been proposed and critical ratio of (H/D) has been predicted. The results of flow visualization are also discussed.
Nomenclature a thermal diffusivity [m2/s] - D external diameter of the plate, internal diameter of screens [m] - g gravitational acceleration [m/s2] - H height of screen [m] - Nu= D/ Nusselt number - Nu (H/D)=0 Nusselt number for plate without screens - Nu H/D Nusselt number for plate with screen of heightH - Ra=g (T w1–T F)D 3/( a) Rayleigh number - Ra H=g (T w–T w1)H 3/( a) Rayleigh number inside screen - q heat flux density [W/m2] - T w surface temperature of the heating plate [°C] - T w1 boundary temperature of the motionless liquid [°C] - T F bulk temperature of the liquid [°C] - heat transfer coefficient [W/(m2·K)] - coefficient of volumetric expansion [1/K] - kinematic viscosity - thermal conductivity [W/(m·K)] 相似文献
Freie Konvektion von horizontalen, seitlich abgeschirmten Platten
Zusammenfassung Es werden experimentelle Untersuchungen der laminaren freien Konvektion an horizontalen, isothermen Flächen mit vertikalen zylindrischen Abschirmflächen beschrieben. Die Schirmdurchmesser (D) waren gleich dem einer Heizplatte, während die Schirmhöhen (H) variiert wurden. Die Resultate, welche für mehrere Wärmeflüsse und mit zwei verschiedenen Flüssigkeiten gewonnen wurden, zeigen, daß — abhängig von VerhältnisH/D der zylindrischen Schirme — der von der Heizplatte an das Fluid übergehende Wärmestrom stark variiert. Drei Bereiche konnten bezüglich des Abschirmeffektes unterschieden werden: erste Hemmung, Verstärkung und zweite Hemmung. Für den Fall der ersten Hemmung wird ein theoretisches Modell vorgeschlagen und das kritischeH/D-Verhältnis vorausberechnet. Abschließend erfolgt die Diskussion von Ergebnissen, welche aus der sichtbaren Darstellung des Strömungsfeldes gewonnen wurde.
Nomenclature a thermal diffusivity [m2/s] - D external diameter of the plate, internal diameter of screens [m] - g gravitational acceleration [m/s2] - H height of screen [m] - Nu= D/ Nusselt number - Nu (H/D)=0 Nusselt number for plate without screens - Nu H/D Nusselt number for plate with screen of heightH - Ra=g (T w1–T F)D 3/( a) Rayleigh number - Ra H=g (T w–T w1)H 3/( a) Rayleigh number inside screen - q heat flux density [W/m2] - T w surface temperature of the heating plate [°C] - T w1 boundary temperature of the motionless liquid [°C] - T F bulk temperature of the liquid [°C] - heat transfer coefficient [W/(m2·K)] - coefficient of volumetric expansion [1/K] - kinematic viscosity - thermal conductivity [W/(m·K)] 相似文献