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21.
VG Adlakha RR Vemuganti 《International Journal of Mathematical Education in Science & Technology》2013,44(5):708-713
In many practical situations scaling the data is necessary to solve linear programs. This note explores the relationships in translating the sensitivity analysis between the original and the scaled problems. 相似文献
22.
An imaging system for the measurement of three-dimensional (3D) scalar gradients in turbulent hydrocarbon flames is described. Combined line imaging of Raman scattering, Rayleigh scattering, and CO laser-induced fluorescence (LIF) allows for simultaneous single-shot line measurements of major species, temperature, mixture fraction, and a one-dimensional surrogate of scalar dissipation rate in hydrocarbon flames, while simultaneous use of two crossed, planar LIF measurements of OH allows for determination of instantaneous flame orientation. In this manner the full 3D scalar dissipation can be estimated in some regions of a turbulent flame on a single-shot basis. 相似文献
23.
Unravelling Secondary Structure Changes on Individual Anionic Polysaccharide Chains by Atomic Force Microscopy
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Larissa Schefer Dr. Jozef Adamcik Prof. Dr. Raffaele Mezzenga 《Angewandte Chemie (International ed. in English)》2014,53(21):5376-5379
The structural conformations of the anionic carrageenan polysaccharides in the presence of monovalent salt close to physiological conditions are studied by atomic force microscopy. Iota‐carrageenan undergoes a coil–helix transition at high ionic strength, whereas lambda‐carrageenan remains in the coiled state. Polymer statistical analysis reveals an increase in persistence length from 22.6±0.2 nm in the random coil, to 26.4±0.2 nm in the ordered helical conformation, indicating an increased rigidity of the helical iota‐carrageenan chains. The many decades‐long debated issue on whether the ordered state can exist as single or double helix, is conclusively resolved by demonstrating the existence of a unimeric helix formed intramolecularly by a single polymer chain. 相似文献
24.
Magnetic Control of Macromolecular Conformations in Supramolecular Anionic Polysaccharide–Iron Complexes
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Larissa Schefer Ariane Bulant Christophe Zeder Dr. Abhijit Saha Prof. Dr. Raffaele Mezzenga 《Angewandte Chemie (International ed. in English)》2015,54(45):13289-13292
The anionic iota carrageenan polysaccharide is enriched with FeII and FeIII by ion exchange against FeSO4 and FeCl3. With divalent iron, portions of polymer chains undergo a secondary structure transition from random coils to single helices. The single‐chain macromolecular conformations can be manipulated by an external magnetic field: upon exposure to 1.1 T, the helical portions exhibit 1.5‐fold stiffening and 1.1‐fold stretching, whereas the coil conformations respond much less as a result of lower contents of condensed iron ions. Along with the coil–helix transition, the trivalent iron triggers the formation of superstructures. The applicability of iron‐enriched iota carrageenan as functional ingredient for food fortification is tested by free Fe2+ and Fe3+ contents, respectively, with the most promising iota‐FeIII yielding 53 % of bound iron, which is due to the superstructures, where the ferric ions are chelated by the supramolecularly self‐assembled polymer host. 相似文献
25.
Application of matrix‐assisted laser‐desorption/ionization time‐of‐flight LIFT for identification of cocoa condensed tannins
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26.
Renata Monteiro-Maia Maria B Ortig?o-de-Sampaio Rosa T Pinho Luiz RR Castello-Branco 《Journal of immune based therapies and vaccines》2006,4(1):4
Background
Oral administration of BCG was the route initially used by Calmette and Guérin, but was replaced by intradermal administration in virtually all countries after the Lubeck accident. However, Brazil continued to administer oral BCG Moreau RDJ, which was maintained until the mid-1970s when it was substituted by the intradermal route. Although BCG vaccination has been used in humans since 1921, little is known of the induced immune response. The aim of this study was to analyse immunological responses after oral vaccination with M. bovis BCG Moreau RDJ. 相似文献27.
To model the thermo-acoustic excitation of flames in practical combustion systems, it is necessary to know how a turbulent flame front responds to an incident acoustic wave. This will depend partly on the way in which the burning velocity responds to the wave. In this investigation, the response of CH4/air and CH4/H2/air mixtures has been observed in a novel flame stabilisation configuration, in which the premixture of fuel and air is made to decelerate under controlled conditions in a wide-angle diffuser. Control is provided by an annular wall-jet of air and by turbulence generators at the inlet. Ignition from the outlet of the diffuser allows an approximately flat flame to propagate downwards and stabilise at a height that depends on the turbulent burning velocity. When the flow is excited acoustically, the ensemble-averaged height oscillates. The fluctuations in flow velocity and flame height are monitored by phase-locked particle image velocimetry and OH-planar laser induced fluorescence, respectively. The flame stabilised against a lower incident velocity as the acoustic amplitude increased. In addition, at the lowest frequency of 52 Hz, the fluctuations in turbulent burning velocity (as represented by the displacement speed) were out-of-phase with the acoustic velocity. Thus, the rate of displacement of the flame front relative to the flow slowed as the flow accelerated, and so the flame movement was bigger than it would have been if the burning velocity had not responded to the acoustic fluctuation. With an increase in frequency to 119 Hz, the relative flame movement became even larger, although the phase-difference was reduced, so the effect on burning velocity was less dramatic. The addition of hydrogen to the methane, so as to maintain the laminar burning velocity at a lower equivalence ratio, suppressed the response at low amplitude, but at a higher amplitude, the effect was reversed. 相似文献
28.
29.
We have investigated the superconducting properties of the Bi1.7 Pb0.3Sr2Ca2−xCe
x
Cu3O10+δ system with x=0.00, 0.02, 0.04, 0.08 and 0.1 by X-ray diffraction and magnetic susceptibility. The substitution of Ce for Ca has been found
to drastically change the superconducting properties of the system. X-ray diffraction studies on these compounds indicate
decrease in the c-parameter with increased substitution of Ce at Ca site and volume fraction of high T
c (2 : 2 : 2 : 3) phase decreases and low T
c phase increases. The magnetic susceptibility of this compound shows that the diamagnetic on set superconducting transition
temperature (onset) varies from 109 K to 51 K for x=0.00, 0.02, 0.04, 0.08 and 0.1. These results suggest the possible existence of Ce in a tetravalent state rather than a trivalent
state in this system; that is, Ca2+ → Ce4+ replacement changes the hole carrier concentration. Hole filling is the cause of lowering T
c of the system. 相似文献
30.
T. V. Drokina G. A. Petrakovskii L. Keller J. Schefer A. D. Balaev A. V. Kartashev D. A. Ivanov 《Journal of Experimental and Theoretical Physics》2011,112(1):121-126
The magnetic structure of the NaFeGe2O6 monoclinic compound has been experimentally investigated using the elastic scattering of neutrons. At a temperature of 1.6
K, an incommensurate magnetic structure has been observed in the form of an antiferromagnetic helix formed by a pairs of the
spins of the Fe3+ ions with helical modulation in the ac plane of the crystal lattice. The wave vector of the magnetic structure has been determined and its temperature behavior
has been studied. The analysis of the temperature dependences of the specific heat and susceptibility, as well as the isotherms
of the field dependence of the magnetization, has revealed the existence of not only the order-disorder magnetic phase transition
at the point T
N = 13 K, but also an additional magnetic phase transition at the point T
c = 11.5 K, which is assumingly an orientation phase transition. 相似文献