497 research outputs found
Apparent negative motion of vortex matter due to inhomogeneous pinning
We investigate the transport of vortices in superconductors with inhomgeneous pinning under a driving force. The inhomogeneity of pinning is simplified as strong-weak pinning regions. It is demonstrated that the interactions between the vortices captured by strong pinning potentials and the vortices in the weak pinning region cause absolute negative motion (ANM) of vortices: The vortices which are climbing toward the high barriers induced by the strong pinning with the help of driving force move toward the opposite direction of the force and back to their equilibrium positions in the weak pinning region as the force decreases or is withdrawn. Our simulations reveal that the hysteresis of ANM is determined by the competition between the speed of the negative motion which depends on the piining inhomogeneity in superconductors and the speed of the driving force. Under the conditions of either larger force scanning rate or higher pinning inhomogeneity, a marked ANM and a larger hysteretic speed-force loop could be observed. This indicates that the time window to observe the ANM should be chosen properly. Moreover, the V-1 characteristics of Ag-sheathed Bi=2223 tapes are measured, and experimental observations are qualitatively in agreement with the simulation
Tibetan sheep are better able to cope with low energy intake than Small-tailed Han sheep due to lower maintenance energy requirements and higher nutrient digestibilities
Tibetan sheep are indigenous to the Qinghai-Tibetan Plateau (QTP) and are well-adapted to and even thrive under the harsh alpine conditions. Small-tailed Han sheep were introduced to the plateau because of their high prolificacy and are maintained mainly in feedlots. Because of their different backgrounds, we hypothesised that Tibetan and Small-tailed Han sheep would differ in their utilization of energy intake and predicted that Tibetan sheep would cope better with low energy intake than Small-tailed Han sheep. To test this prediction, we determined nutrient digestibilities, energy requirements for maintenance and blood metabolite and hormone concentrations involved in energy metabolism in these breeds. Sheep of each breed (n = 24 of each, all wethers and 1.5 years of age) were distributed randomly into one of four groups and offered ad libitum diets of different digestible energy (DE) densities: 8.21, 9.33, 10.45 and 11.57 MJ DE/kg Dry matter (DM). Following 42 d of measuring feed intake, a 1-week digestion and metabolism experiment was done. DM intakes did not differ between breeds nor among treatments but, by design, DE intake increased linearly in both breeds as dietary energy level increased (P < 0.001). The average daily gain (ADG) was significantly greater in the Tibetan than Small-tailed Han sheep (P = 0.003) and increased linearly in both breeds (P < 0.001). In addition, from the regression analysis of ADG on DE intake, daily DE maintenance requirements were lower for Tibetan than for Small-tailed Han sheep (0.41 vs 0.50 MJ/BW0.75, P < 0.05). The DE and metabolizable energy (ME) digestibilities were higher in the Tibetan than Small-tailed Han sheep (P < 0.001) and increased linearly as the energy level increased in the diet (P < 0.001). At the lowest energy treatment, Tibetan sheep when compared with Small-tailed Han sheep, had: 1) higher serum glucose and glucagon, but lower insulin concentrations (P < 0.05), which indicated a higher capacity for gluconeogenesis and ability to regulate glucose metabolism; and 2) higher non-esterified fatty acids (NEFA) and lower very low density lipoprotein (VLDL) and triglyceride (TG) concentrations (P < 0.05), which indicated a higher capacity for NEFA oxidation but lower ability for triglyceride (TG) synthesis. We concluded that our prediction was supported as these differences between breeds conferred an advantage for Tibetan over Small-tailed Han sheep to cope better with low energy diets
Dynamic and Postdeformation Recrystallization of Nuclear-Grade 316LN Stainless Steel
Nuclear-grade 316LN stainless steel was subjected to single and double compressions at 1173β1473 K and strain rates of 0.01β10 sβ»ΒΉ. The dynamic and postdeformation recrystallization was investigated through analysis of the stressβstrain curves and microstructure evolution. The thermal deformation equation and the quantitative relationships between the critical stress for the initiation of dynamic recrystallization and the ZenerβHollomon parameter, Z, and between the dynamic recrystallization grain size D and Z were derived. Dynamic recrystallization developed through an ordinary mechanism at low Z values and through a necklace mechanism at high Z values, with a critical Z value of about 3.6 10ΒΉβΆ . At 1273β1473 K, softening of 316LN stainless steel after deformation was characterized by an Avrami-type equation, where the Avrami parameter, n, has no appreciable temperature dependence, and an average value of n and the activation energy, Qrex , were 0.68 and 129 kJ/mol, respectively.ΠΠ΅ΡΠΆΠ°Π²Π΅ΡΡΠ°Ρ ΡΡΠ°Π»Ρ 316LN ΡΠ΄Π΅ΡΠ½ΠΎΠ³ΠΎ ΠΊΠ»Π°ΡΡΠ° ΠΏΠΎΠ΄Π²Π΅ΡΠ³Π°Π»Π°ΡΡ ΠΎΠ΄Π½ΠΎ- ΠΈ Π΄Π²ΡΠΊΡΠ°ΡΠ½ΠΎΠΌΡ ΡΠΆΠ°ΡΠΈΡ ΠΏΡΠΈ 1173...1473 Π ΠΈ ΡΠΊΠΎΡΠΎΡΡΠΈ Π΄Π΅ΡΠΎΡΠΌΠ°ΡΠΈΠΈ 0,01...10 Ρβ»ΒΉ. ΠΠΈΠ½Π°ΠΌΠΈΡΠ΅ΡΠΊΠ°Ρ ΠΈ ΠΏΠΎΡΡΠ΄Π΅ΡΠΎΡΠΌΠ°ΡΠΈΠΎΠ½Π½Π°Ρ ΡΠ΅ΠΊΡΠΈΡΡΠ°Π»Π»ΠΈΠ·Π°ΡΠΈΡ ΠΈΠ·ΡΡΠ°Π»Π°ΡΡ Ρ ΠΏΠΎΠΌΠΎΡΡΡ Π°Π½Π°Π»ΠΈΠ·Π° Π·Π°Π²ΠΈΡΠΈΠΌΠΎΡΡΠΈ Π΄Π΅ΡΠΎΡΠΌΠ°ΡΠΈΠΈ ΠΎΡ Π½Π°ΠΏΡΡΠΆΠ΅Π½ΠΈΡ ΠΈ ΡΠ°Π·Π²ΠΈΡΠΈΡ ΠΌΠΈΠΊΡΠΎΡΡΡΡΠΊΡΡΡΡ. ΠΡΠ»ΠΈ Π²ΡΠ²Π΅Π΄Π΅Π½Ρ ΡΡΠ°Π²Π½Π΅Π½ΠΈΠ΅ ΡΠ΅ΠΏΠ»ΠΎΠ²ΠΎΠΉ Π΄Π΅ΡΠΎΡΠΌΠ°ΡΠΈΠΈ ΠΈ ΠΊΠΎΠ»ΠΈΡΠ΅ΡΡΠ²Π΅Π½Π½ΡΠ΅ Π·Π°Π²ΠΈΡΠΈΠΌΠΎΡΡΠΈ ΠΌΠ΅ΠΆΠ΄Ρ ΠΊΡΠΈΡΠΈΡΠ΅ΡΠΊΠΈΠΌ Π½Π°ΠΏΡΡΠΆΠ΅Π½ΠΈΠ΅ΠΌ ΠΈΠ½ΠΈΡΠΈΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π΄ΠΈΠ½Π°ΠΌΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΠ΅ΠΊΡΠΈΡΡΠ°Π»Π»ΠΈΠ·Π°ΡΠΈΠΈ ΠΈ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠΌ ΠΠ΅Π½Π΅ΡΠ° Π₯ΠΎΠ»Π»ΠΎΠΌΠΎΠ½Π° Z, Π° ΡΠ°ΠΊΠΆΠ΅ ΠΌΠ΅ΠΆΠ΄Ρ ΡΠ°Π·ΠΌΠ΅ΡΠΎΠΌ Π·Π΅ΡΠ½Π° D ΠΏΡΠΈ Π΄ΠΈΠ½Π°ΠΌΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΠ΅ΠΊΡΠΈΡΡΠ°Π»Π»ΠΈΠ·Π°ΡΠΈΠΈ ΠΈ Z. ΠΠΈΠ½Π°ΠΌΠΈΡΠ΅ΡΠΊΠ°Ρ ΡΠ΅ΠΊΡΠΈΡΡΠ°Π»Π»ΠΈΠ·Π°ΡΠΈΡ ΡΠ°Π·Π²ΠΈΠ²Π°Π»Π°ΡΡ ΠΏΠΎ ΠΎΠ±ΡΡΠ½ΠΎΠΌΡ ΠΌΠ΅Ρ
Π°Π½ΠΈΠ·ΠΌΡ ΠΏΡΠΈ Π½ΠΈΠ·ΠΊΠΈΡ
Π·Π½Π°ΡΠ΅Π½ΠΈΡΡ
Z ΠΈ ΠΏΠΎ ΠΌΠ΅Ρ
Π°Π½ΠΈΠ·ΠΌΡ ΠΎΠΆΠ΅ΡΠ΅Π»ΡΡ ΠΏΡΠΈ Π²ΡΡΠΎΠΊΠΈΡ
Π·Π½Π°ΡΠ΅Π½ΠΈΡΡ
Z, ΠΏΡΠΈ ΠΊΡΠΈΡΠΈΡΠ΅ΡΠΊΠΎΠΌ Π·Π½Π°ΡΠ΅Π½ΠΈΠΈ Z ΠΏΡΠΈΠΌΠ΅ΡΠ½ΠΎ 3 6 10ΒΉβΆ. ΠΡΠΈ 1273...1473 Π ΡΠ°Π·ΡΠΏΡΠΎΡΠ½Π΅Π½ΠΈΠ΅ Π½Π΅ΡΠΆΠ°Π²Π΅ΡΡΠ΅ΠΉ ΡΡΠ°Π»ΠΈ 316LN ΠΏΠΎΡΠ»Π΅ Π΄Π΅ΡΠΎΡΠΌΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΠΎΠΏΠΈΡΡΠ²Π°Π΅ΡΡΡ ΡΡΠ°Π²Π½Π΅Π½ΠΈΠ΅ΠΌ ΠΠ²ΡΠ°ΠΌΠΈ, Π³Π΄Π΅ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡ ΠΠ²ΡΠ°ΠΌΠΈ n Π½Π΅ ΠΏΡΠΎΡΠ²Π»ΡΠ΅Ρ Π²ΡΡΠ°ΠΆΠ΅Π½Π½ΠΎΠΉ ΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΠ½ΠΎΠΉ Π·Π°Π²ΠΈΡΠΈΠΌΠΎΡΡΠΈ, Π° Π΅Π³ΠΎ ΡΡΠ΅Π΄Π½Π΅Π΅ Π·Π½Π°ΡΠ΅Π½ΠΈΠ΅ ΠΈ ΡΠ½Π΅ΡΠ³ΠΈΡ Π°ΠΊΡΠΈΠ²Π°ΡΠΈΠΈ Qrex ΡΠΎΡΡΠ°Π²Π»ΡΡΡ 0,68 ΠΈ 129 ΠΊΠΠΆ/ΠΌΠΎΠ»Ρ ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²Π΅Π½Π½ΠΎ
Transpolar arc observation after solar wind entry into the high-latitude magnetosphere
Recently, Cluster observations have revealed the presence of new regions of solar wind plasma entry at the high-latitude magnetospheric lobes tailward of the cusp region, mostly during periods of northward interplanetary magnetic field. In this study, observations from the Global Ultraviolet Imager (GUVI) experiment on board the TIMED spacecraft and Wideband Imaging Camera imager on board the IMAGE satellite are used to investigate a possible link between solar wind entry and the formation of transpolar arcs in the polar cap. We focus on a case when transpolar arc formation was observed twice right after the two solar wind entry events were detected by the Cluster spacecraft. In addition, GUVI and IMAGE observations show a simultaneous occurrence of auroral activity at low and high latitudes after the second entry event, possibly indicating a two-part structure of the continuous band of the transpolar arc
Solar wind pressure pulseβdriven magnetospheric vortices and their global consequences
We report the in situ observation of a plasma vortex induced by a solar wind dynamic pressure enhancement in the nightside plasma sheet using multipoint measurements from Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellites. The vortex has a scale of 5β10 Re and propagates several Re downtail, expanding while propagating. The features of the vortex are consistent with the prediction of the Sibeck (1990) model, and the vortex can penetrate deep (~8 Re ) in the dawnβdusk direction and couple to field line oscillations. Global magnetohydrodynamics simulations are carried out, and it is found that the simulation and observations are consistent with each other. Data from THEMIS ground magnetometer stations indicate a poleward propagating vortex in the ionosphere, with a rotational sense consistent with the existence of the vortex observed in the magnetotail. Key Points Solar wind pressure pulseβdriven vortex was observed in the magnetosphere Simulation and ground magnetic field data confirm this tailward moving vortex The vortex can penetrate deep inside the tail plasma sheet and couple to FLRsPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/107999/1/jgra51112.pd
Theoretical study of the two-proton halo candidate Ne including contributions from resonant continuum and pairing correlations
With the relativistic Coulomb wave function boundary condition, the energies,
widths and wave functions of the single proton resonant orbitals for Ne
are studied by the analytical continuation of the coupling constant (ACCC)
approach within the framework of the relativistic mean field (RMF) theory.
Pairing correlations and contributions from the single-particle resonant
orbitals in the continuum are taken into consideration by the resonant
Bardeen-Cooper-Schrieffer (BCS) approach, in which constant pairing strength is
used. It can be seen that the fully self-consistent calculations with NL3 and
NLSH effective interactions mostly agree with the latest experimental
measurements, such as binding energies, matter radii, charge radii and
densities. The energy of 2s orbital is slightly higher than that
of orbital, and the occupation probability of the
2s orbital is about 20%, which are in accordance with the
shell model calculation and three-body model estimation
Original and secondary highβfrequency sandstorm zones in the loess plateau region, china
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