The crystal structure of the U3Si2 line compound in the U-Si system was investigated as a function of temperature from room temperature to 1373 K using high temperature neutron time-of-flight diffraction on the High-p...
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We have probed directly the temperature and magnetic field dependence of pinned uncompensated magnetization at the interface of antiferromagnetic FeF2 with Cu, using FeF2−Cu−Co spin valves. Electrons polarized by the ...
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We have probed directly the temperature and magnetic field dependence of pinned uncompensated magnetization at the interface of antiferromagnetic FeF2 with Cu, using FeF2−Cu−Co spin valves. Electrons polarized by the Co layer are scattered by the pinned uncompensated moments at the FeF2−Cu interface giving rise to giant magnetoresistance. We determined the direction and magnitude of the pinned uncompensated magnetization at different magnetic fields and temperatures using the angular dependencies of resistance. The strong FeF2 anisotropy pins the uncompensated magnetization along the easy axis independent of the cooling field orientation. Most interestingly, magnetic fields as high as 90 kOe cannot break the pinning at the FeF2−Cu interface. This proves that the pinned interfacial magnetization is strongly coupled to the antiferromagnetic order inside the bulk FeF2 layer. Studies as a function of FeF2 crystalline orientation show that uncompensated spins are only detected in a spin valve with (110) crystal orientation, but not in valves containing FeF2(100) and FeF2(001). This observation is in agreement with symmetry-related considerations which predict the equilibrium boundary magnetization for the FeF2(110) layer.
Colloidal particles in liquid crystals tend to induce topological defects and distortions of the molecular alignment within the surrounding anisotropic host medium, which results in elasticity-mediated interactions no...
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In this study, highly porous forsterite scaffolds with interconnected porosities were synthesized using multi-step sintering(MSS) method. The starting powder was nanosized forsterite, which was synthesized from talc a...
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In this study, highly porous forsterite scaffolds with interconnected porosities were synthesized using multi-step sintering(MSS) method. The starting powder was nanosized forsterite, which was synthesized from talc and magnesium carbonate powders. The phase composition, average particle size and morphology of the produced forsterite powder were characterized by X-ray diffraction technique(XRD) and transition electron microscopy(TEM). Forsterite scaffolds were produced by foamy method using polymeric sponges. MSS process including three steps was used to efficiently sinter the forsterite nanopowders without destroying the initial porous structure of polymeric sponges. The results showed that MSS technique is an efficient and appropriate procedure to produce highly porous forsterite scaffolds with pore size in the range of 100-300 μm. The compressive strength, compressive modulus and porosity of C12 specimen(sintered at 1650℃ for 1 h with subsequent annealing at 1000℃ for 1000 min) was 1.88 MPa, 29.2 MPa, and 72.4%, respectively, which is very close to that of cancellous bone. The approach studied in this research can be developed for other nanostructure ceramics to produce highly porous scaffolds with interconnected porosities for load bearing applications.
Animal behavioral experiments like operant conditionings are common techniques in the research of biomedicalsciences. However, Manual operation of behavioral experiments is usually inaccurate, prone to mistakes and q...
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ISBN:
(纸本)9781450372510
Animal behavioral experiments like operant conditionings are common techniques in the research of biomedicalsciences. However, Manual operation of behavioral experiments is usually inaccurate, prone to mistakes and quite time-consuming. It cannot accomplish some complex experiments such as training animals to discriminate different sounds of different frequencies, triggering data acquisition equipment to record electrophysiological signals immediately after an acoustic/optical stimulus. Here, we designed and implemented an automatic apparatus for animal behavior studies, which is competent to perform different kinds of complex stimulus-reward experiments by software settings. The apparatus is consisted of a microcontroller and several peripheral components. programmable procedures are controlled by the microcontroller for training or testing of rodents, in no need of human intervention. Parameters such as the color, duration and timing of light stimuli, or the frequency, duration and patterns of sound are adjustable by software. Using this apparatus, we conducted experiments and verified that rats had the ability to discriminate sound stimuli with different duration or different cycles. This apparatus worked automatically, stably and reliably, with less manual operation and higher efficiency. It would also be a useful tool for other studies such as learning and memory experiments.
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