Rectifying characteristics, magnetic tunability, and photovoltaic response in La0.8Hf0.2MnO3/0.7 wt% Nb-SrTiO3 heteroepitaxial junctions

Heterojunctions composed of tetravalent cation-doped La 0.8Hf 0.2MnO 3 (LHMO) and 0.7 wt Nb-doped SrTiO 3 were fabricated using pulsed laser deposition method and investigated under different fields (electric, magnetic, and optic). The heterojunctions exhibited excellent rectifying behavior in a wide temperature range and significant magnetic field modulated properties. Prominent photovoltaic effect was also observed in the formed junctions. Special attention has been paid to the temperature dependence of the diffusion voltage (V d) and photovoltage (V oc). When temperature increased from 40 K to 300 K, V d decreased from 1.13 V to 0.16 V. It is notable that, under illumination of a light with λ = 532 nm, V oc dropped from 650 to 80 mV. No sudden change of V d and V oc was observed at the metal-insulator transition temperature, which is probably caused by the band structure of the LHMO. © 2012 American Institute of Physics.published_or_final_versio

Influences of leakage currents on the transport properties and photoelectric effects in heterojunctions composed of colossal magnetoresistance manganites and Nb-doped titanates

The effects of leakage currents were investigated for Pr 0.7Sr 0.3MnO 3/Nb-SrTiO 3 heterojunctions. It was found that small amounts of leakage currents could cause pronounced detriment to the rectifying properties but had very limited impacts on the barrier heights determined from the forward currents. Significant open circuit voltages V OC were observed when the highly rectified junctions were illuminated by a visible light with a wavelength of 532 nm. For the less rectified junctions, the leakage currents reduced V OC severely and resulted in an anomalous temperature dependence of V OC. Theories for semiconductor contacts were employed in order to discuss these results. © 2012 American Institute of Physics.published_or_final_versio

Electric currents induced step-like resistive jumps and negative differential resistance in thin films of Nd0.7Sr0.3MnO3

Electric-currents-induced emergent phenomena were found in microbridges of Nd 0.7Sr 0.3MnO 3. After the samples were processed by currents of high densities, a second metal-insulator transition appeared at low temperatures. This resistance peak was very sensitive to weak currents. More salient features were the step-like resistance jumps. At temperatures near these resistance steps, negative differential resistance was observed. Interfacial effects related to electrodes could be ruled out. These effects might be due to current-enhanced inhomogeneity. © 2012 American Institute of Physics.published_or_final_versio

Phase diagram and spin-glass phenomena in electron-doped La1-xHfxMnO3 (0.05 ≤ x ≤ 0.3) manganite oxides

The effects of tetravalent hafnium doping on the structural, transport, and magnetic properties of polycrystalline La1−xHfxMnO3 (LHMO) (0.05 ≤ x ≤ 0.3) were investigated systematically. LHMO exhibited a typical colossal magnetoresistance effect via the double-exchange between Mn2+ and Mn3+ ions, instead of that between Mn3+ and Mn4+ ions in hole-doped manganites. A phase diagram was obtained for the first time through magnetization and resistance measurements in a broad temperature range. As the Hf concentration varied from x = 0.05 to 0.3, the Curie point and metal-to-insulator transition temperature increased significantly, whereas the magnetization and resistivity decreased remarkably. An abnormal enhancement of the magnetization was observed at about 42 K. It was further confirmed that a second magnetic phase MnO2 in LHMO gives rise to such a phenomenon. The possible causes are discussed in detail. The dynamic magnetic properties of LHMO, including relaxation and aging processes, were studied, demonstrating a spin-glass state at low temperature accompanied by a ferromagnetic phase.published_or_final_versio

An optical coherence tomography (OCT)-based air jet indentation system for measuring the mechanical properties of soft tissues

2008-2009 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Human motion tracking based on complementary Kalman filter

Miniaturized Inertial Measurement Unit (IMU) has been widely used in many motion capturing applications. In order to overcome stability and noise problems of IMU, a lot of efforts have been made to develop appropriate data fusion method to obtain reliable orientation estimation from IMU data. This article presents a method which models the errors of orientation, gyroscope bias and magnetic disturbance, and compensate the errors of state variables with complementary Kalman filter in a body motion capture system. Experimental results have shown that the proposed method significantly reduces the accumulative orientation estimation errors

Response of innate immune factors in abalone Haliotis diversicolor supertexta to pathogenic or nonpathogenic infection

Cell free hemolymph from Haliotis diversicolor supertexta was prepared from fluid collected at 1, 4, 8. 12. 24, 48 96 It after injection with either Escherichia coli, Vibrio parahaemolyticus or 0.9 NaCl solution (control group). The response of selected innate immune parameters (lysozyme, antibacterial activity, alkaline phosphatase, acid phosphatase, phenoloxidase, and superoxide dismutase) was investigated. Results showed that the activities of ACP (Acid Phosphatase) from abalone injected with V. parahaemolyticus were much higher than that of the control group at 24 h after injection. The ALP (Alkaline Phosphatase) activities of abalone challenged with V. parahaemolyticus were significantly higher than those of the control group at 8 h and increased further up to 48 h after the challenge. In contrast, the activities of ALP and ACP in the E. coli-challenged group showed no statistically significant differences at any of the sampling times. The activities of SOD (Superoxide Dismutase) in cell free hemolymph from the V. parahaemolyticus-exposed group were significantly lower than those of the control group at both I h and 24 h, whereas there was no difference in SOD activity observed in the group exposed to E. coli at any of the sampling times. The activities of lysozyme and phenoloxidase in Haliotis diversicolor were relatively low in both control and bacteria-ex posed groups when compared with reports for other invertebrates no significant difference was found between the infected groups and the control for these two parameters, due to the low activities and high individual variance

Rapid detection of adulterated drugs in herbal dietary supplements by wooden-tip electrospray ionization mass spectrometry

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Histamine increases neuronal excitability and sensitivity of the lateral vestibular nucleus and promotes motor behaviors via HCN channel coupled to H2 receptor

published_or_final_versio

Environmental footprint assessment of green campus from a food-water-energy nexus perspective

Universities not only can be considered as small communities due to their intensive population and their provision of complex services, but also play a vital role in the education system for global sustainable future. Thus, the environmental impacts and green operation of universities has great reference value for the design of sustainable development. In this study, we develop an environmental footprint framework based on life cycle analysis (LCA) to systematically and comprehensively understand how universities interact with the hydrologic cycle, energy resources and climate. Using Keele University in UK as an example, we further quantified the nexus and trade-offs between environmental elements including water, energy, food, waste and carbon emissions. We believe that this method will contribute to the development of footprint assessment and sustainable development, and the findings could serve as reference for policy-makers who are interested in developing green campuses