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To explore the loss regularity of water and fertilizer in the ancient course of the Yellow River in cultivation of Chaenomeles sinensis and Prunus armeniaca × sibirica, three water management measures were employed: mulching with plastic films (Wmp), mulching with cornstalk (Wmc) and conventional management (Wck). Meanwhile, the effects of irrigation times, namely slow-release N, P and K fertilizer (NPK SRFs), compound N, P and K fertilizer (NPK CFs), urea fertilizer (Urea Fs), and unfertilized (Fck) were studied. Results showed that the soil water content was effectively increased using Wmp and Wmc, Wmp effectively extended the water retention time and soil temperature stability. After three irrigations, NPK SRFs, NPK CFs and Urea Fs were completely lost. The compound fertilizer had a significantly higher nutrient maintenance capacity than urea. Furthermore, the application of urea had to be balanced to avoid an excessive rise in soil pH. The growth of C. sinensis and P. armeniaca × sibirica was significantly better than traditional model. It is suggested to use crop straw to maintain water levels and improve soil organic matter, and replace urea by applying a compound fertilizer in the early and late growing season in sandy soil.

The effects of short fibres on sintering kinetics and shrinkage anisotropy during sintering of composite glass powder compacts are analysed in detail. In sintering composites, short fibres are modelled as prolate spheroidal rigid inclusions randomly dispersed in viscous matrix. Based on the Mori–Tanaka mean-field formulation, the fibre orientation distribution and aspect ratio on viscous matrix sintering have been taken into account. The comprehensively qualitative results for the effects of fibres on whole sintering rate and anisotropy varying with fibre different orientation distributions, aspect ratios and volume fractions are computed. Furthermore, the average internal matrix stress and interfacial normal stresses due to incompatible sintering rates are investigated in this paper.

A summary of detailed measurements of the field- and temperature-dependent ac susceptibility, the field-cooled and zero-field cooled magnetization, coercive field and the resistivity in zero field and applied field of 1.5 T is presented for hole-doped La1−xMgxMnO3 (0.05 ≤ x ≤ 0.4). Measurements of the ac susceptibility enable estimates of the (effective) critical exponents γ, β and δ to be made, which, when combined with the magnetization data, enable a phase diagram to be proposed. The transport data highlight the suppression of a metal–insulator transition in these systems with small average A-site radius. Furthermore, the transport behaviour is shown to be consistent with the predictions for charge transport by conventional small polaron hopping in both the paramagnetic and ferromagnetic phases, but inconsistent with recent quantitative predictions for magnetic small polaron-mediated conduction in a phase-separated picture.

The transport and magnetic behaviours of Ar-annealed (O-depleted) bulk samples of an archetypal, `optimally' doped manganese perovskite, La0.67Ca0.33MnO3, are reported, analysed and compared with those of an untreated specimen. These indicate that the transport data for both the paramagnetic and ferromagnetic phases of the O-depleted system are consistent with the predictions based on polaronic hopping, specifically non-adiabatic small-polaron hopping (on the basis of the internal consistency of estimates for the characteristic frequency Ω0 from both the adiabatic and non-adiabatic formalisms). These results yield indirect support for models which attribute transport in doped perovskites in general, and the colossal-magnetoresistance phenomenon in particular, to polaronic behaviour.

Measurements of the field and temperature dependent electrical resistivity and ac susceptibility of LaMnO3 doped with 5% Mg are presented. Analysis of these data reveal that while this system undergoes a ferromagnetic transition at Tc = 147.2?0.2?K, it remains semiconducting over the entire temperature range examined (90?T?330?K). In particular, these resistivity data are well fit by the form appropriate for adiabatic small polaron hopping for both T>Tc and T

Detailed measurements of the field- and temperature-dependent ac susceptibility and magnetization of LaMnO3 substituted with 5 at.% of the divalent cation Mg are presented. This system is a semiconducting ferromagnet at low temperature; in particular, analysis of these data yields Tc = 147.2±0.2 K, with critical exponents δ = 4.75±0.15 (from the field dependence of the susceptibility along the `crossover' line, and confirmed by measurements along the critical isotherm), γ + β = 1.75±0.05 (from the temperature dependence of the crossover line) and γ = 1.39±0.05 (from the temperature dependence of the susceptibility along the same line). Within experimental uncertainty these exponent values agree with those predicted by the isotropic, three-dimensional Heisenberg model. Nevertheless this system exhibits some unusual characteristics, specifically in the temperature dependence of the (low-) field-cooled and zero-field-cooled magnetization. The latter have been modelled by a Preisach-based approach, which helps to resolve a ubiquitous dilemma in the doped manganites, viz. the appearance of a technical hardness irreconcilable with low coercive field values. A possible origin for the large, reversible component in the response below Tc is presented.

Detailed alternating-current susceptibility and low-field magnetization measurements on samples of Mg-substituted LaMnO3, which x-ray data indicate are orthorhombic, not rhombohedral, show that (i) various oxides of Mn and Mg, which should be present if self-doping occurs, are present at such low levels that they cannot be detected and (ii) the extent of the self-doping of the parent compound La1-yMnO3, if it occurs at all in the sample in question, is at the 1% level. This confirms that Mg does substitute for La in this system.

A two-color time-resolved Kerr rotation spectroscopy system was built, with a femtosecond Ti:sapphire laser and a photonic crystal fiber, to study coherent spin transfer processes in an InGaAs/GaAs quantum well sample. The femtosecond Ti:sapphire laser plays two roles: besides providing a pump beam with a tunable wavelength, it also excites the photonic crystal fiber to generate supercontinuum light ranging from 500 nm to 1600 nm, from which a probe beam with a desirable wavelength is selected with a suitable interference filter. With such a system, we studied spin transfer processes between two semiconductors of different gaps in an InGaAs/GaAs quantum well sample. We found that electron spins generated in the GaAs barrier were transferred coherently into the InGaAs quantum well. A model based on rate equations and Bloch-Torrey equations is used to describe the coherent spin transfer processes quantitatively. With this model, we obtain an effective electron spin accumulation time of 21 ps in the InGaAs quantum well.