Core-shell heterostructured phase change nanowire multistate memory

Phase-change memory, which switches reversibly between crystalline and amorphous phases, is promising for next generation data-storage devices. In this work, we present a novel, nonbinary data-storage device using core-shell nanowires to significantly enhance memory capacity by combining two phase-change materials with different electronic and thermal properties to engineer different onsets of amorphous-crystalline transitions. Electric-field induced sequential amorphous-crystalline transition in core-shell nanowires displays three distinct electronic states with high, low, and intermediate resistances, assigned as data "0", "1", and "2".     

Effect of Magnetopriming on Photosynthetic Performance of Plants

Magnetopriming has emerged as a promising seed-priming method, improving seed vigor, plant performance and productivity under both normal and stressed conditions. Various recent reports have demonstrated that improved photosynthesis can lead to higher biomass accumulation and overall crop yield. The major focus of the present review is magnetopriming-based, improved growth parameters, which ultimately favor increased photosynthetic performance. The plants originating from magnetoprimed seeds showed increased plant height, leaf area, fresh weight, thick midrib and minor veins. Similarly, chlorophyll and carotenoid contents, efficiency of PSII, quantum yield of electron transport, stomatal conductance, and activities of carbonic anhydrase (CA), Rubisco and PEP-carboxylase enzymes are enhanced with magnetopriming of the seeds. In addition, a higher fluorescence yield at the J-I-P phase in polyphasic chlorophyll a fluorescence (OJIP) transient curves was observed in plants originating from magnetoprimed seeds. Here, we have presented an overview of available studies supporting the magnetopriming-based improvement of various parameters determining the photosynthetic performance of crop plants, which consequently increases crop yield. Additionally, we suggest the need for more in-depth molecular analysis in the future to shed light upon hidden regulatory mechanisms involved in magnetopriming-based, improved photosynthetic performance.     

Study of age and height wise variability on calorific value and other fuel properties of Eucalyptus hybrid, Acacia auriculaeformis and Casuarina equisetifolia

The age and height wise variations in the fuel properties (basic density, calorific value, proximate and elemental parameters) of three short rotation forestry species i.e., Eucalyptus hybrid, Acacia auriculaeformis and Casuarina equisetifolia have been investigated. The fuel properties parameters were evaluated from the test samples of different age from 2 to 6 year and the samples obtained from three different height of trees i.e., stump height, diameter at breast height and top. A marginal increase in the calorific value with the age of tree (2-6 years) was found in all the species, the variation being significant in E. hybrid and C. equisetifolia. The basic density values were also found significantly different in E. hybrid and C. equisetifolia at lower ages (2-6 years). However, when the results were analyzed along the tree height, the calorific values were found to decrease along the stem length towards the tree-top in A. auriculaeformis and C. equisetifolia. The ash content in general was found to be higher in the top portions of the trees, and the same was found significantly higher in case of A. auriculaeformis. There was no particular trend observed for volatile matter content and the fixed carbon content with age. The fuel properties of lower age trees were compared with that of a mature tree (20 years of age) of same species. In general, the fuel properties of mature trees were found to be better than trees of lower age.     

空穴注入层技术在聚合体OLED器件中的重要性

空穴注入层技术可降低OLED成本和提高其生产效率,是使柔性OLED显示成为商品化的一个重要因素。     

On the influence of ply-angle on damping and modulus of elasticity of a metal-matrix composite

The central objective of the classical laminate theory is topredict the properties of a laminate having an arbitrary lay-up, taking as its input themeasured properties of an individual lamina. Whereas a fair amount of work has been done concerning the prediction of the laminate stiffness, relatively little attention has been paid to the prediction of laminate damping. A recent model by Ni and Adams[1] fills this gap. The model is not exact and, of necessity, is based on some simplifying assumptions. The objective of this paper is to compare the predictions of their model with the results of a careful and detailed experimental investigation of the problem as it concerns metal-matrix composites. Flexural modulus and flexural damping of a continuous graphite/ aluminum composite of [±θ] _s lay-up were measured forθ = 0, 15, 30, 45, 60, 75, and 90 deg. These were compared with the predictions of a slightly modified form of the Ni and Adams model; the model was modified to include theɛ _y ,σ _y , andτ _xy terms which were ignored in the earlier work, where (x, y, z) is the laminate coordinate system. Excellent agreement between the theory and experimental results was observed. Formerly Graduate Student, Department of Aerospace Engineering, Texas A & M University This paper is based on a presentation made in the symposium “Acoustic/Vibration Damping Materials” presented during the TMS Fall Meeting, Indianapolis, IN, October 1–5, 1989, under the auspices of the TMS Physical Metallurgy Committee.     

A generic approach for embedded catalyst-supported vertically aligned nanowire growth

We demonstrate a general approach for growing vertically aligned, single-crystalline nanowires of any material on arbitrary substrates by using plasma-sputtered Au/Pd thin films as a catalyst through the vapor-liquid-solid process. The high-energy sputtered Au/Pd atoms form a reactive interface with the substrate forming nanoclusters which get embedded in the substrate, thus providing mechanical stability for vertically aligned nanowire growth. We demonstrate that our approach for vertically aligned nanowire growth is generic and can be extended to various complex substrates such as conducting indium tin oxide.     

Size-dependent surface-induced heterogeneous nucleation driven phase-change in Ge2Sb2Te5 nanowires

By combining electron microscopy and size-dependent electrical measurements, we demonstrate surface-induced heterogeneous nucleation-dominant mechanism for recrystallization of amorphous phase-change Ge2Sb2Te5 nanowires. Heterogeneous nucleation theory quantitatively predicts the nucleation rates that vary by 5 orders of magnitude from 190 to 20 nm lengthscales. Our work demonstrates that increasing the surface-to-volume ratio of nanowires has two effects: lowering of the activation energy barrier due to phonon instability and providing nucleation sites for recrystallization. The systematic study of the effect of surface in phase-change behavior is critical for understanding nanoscale phase-transitions and design of nonvolatile memory devices.     

Silicon Lens Optimization to Create Diffuse,Uniform Illumination from Incoherent THz Source Arrays

Journal of Infrared, Millimeter, and Terahertz Waves - Arrays of terahertz (THz) sources provide a pathway to overcoming the radiation power limitations of single sources. Several independent...