Search

(Zr54Al10.2Ni9.4Cu26.4)100−xTix (x = 0–0.5, at%) bulk metallic glasses were prepared by water-cooled copper suction casting method. The Ti microalloying effect on glass forming ability and physical and chemical properties of Zr54Al10.2Ni9.4Cu26.4 glass forming alloy were systematically investigated. The glass forming ability is the largest for the Zr-based alloy with 0.3 at% Ti. The glass transition temperature is decreased by the Ti addition, while the supercooled liquid region is broadened. Both strength and plasticity are significantly enhanced by the Ti addition. The yield strength and the fracture strength firstly increase and then decrease when the Ti content reaches up to 0.3 at%. The plastic strain and the fracture strain increase with increasing Ti content. In addition, the corrosion potential is slightly decreased by the Ti addition. The corrosion current density increases with increasing Ti content. The pitting corrosion becomes increasingly serious with increasing Ti content. The honeycomb corrossion structure can be clearly observed when the Ti content reaches up to 0.5 at%. The corresponding mechanisms are also discussed in detail.

Aflatoxins are toxic, mutagenic, and carcinogenic compounds that can contaminate various types of agro-products, among which peanuts are one of the most susceptible foodstuffs. In the current study, a total of 2494 peanut samples collected from four major peanut producing areas in China (Liaoning, Henan, Sichuan, and Guangdong provinces) from 2010 to 2013 were investigated for the occurrence of aflatoxins. A close relationship can be concluded between the result and the weather a month before harvest. According to the relationship, the highest aflatoxin contamination level occurred under the climatic conditions where precipitation was rare and the mean temperature was close to 23 °C, the minimum temperature was approximately 20 °C, and the maximum temperature was about 29 °C. This survey provided valuable information on aflatoxin contamination in pre-harvest peanuts under different agro-environmental conditions in China and laid a foundation for predicting aflatoxin contamination, which would be essential for taking preventive measures to alleviate pre-harvest aflatoxin contamination of peanuts.

(Zr53Al11.6Ni11.7Cu23.7)1-x(Fe77.1C22.9)x (x = 0–2.2 at.%) bulk metallic glasses (BMGs) were prepared by water cooling copper mold suction casting and their isochronous crystallization characteristics are investigated. The glass transition temperature, crystallization temperature, and crystallization peak temperature for all studied Zr-based BMGs firstly increase with increasing heating rate, and then decrease when the heating rate increases up to 60 K/min for the BMGs (0 ≤ x ≤ 0.88 at.%) and 80 K/min for the BMGs (1.32 ≤ x ≤ 2.20 at.%). The glass transition temperature, crystallization temperature, glass transition activiation energy, crystallization activiation energy, and activiation energy for crystallization peak temperature of the Fe- and C-free Zr-based BMG are the smallest among the studied BMGs, indicating that Fe and C additions are benificial to delaying the glass transition and the crystallization. Fe and C additions influence more significantly on the glass transition than on the crystallization. The local crystallization activiation energy for the Fe- and C-free BMG are the smallest among the studied BMGs, indicating that the crystallization is easy for the Fe- and C-free BMG. The peak height of local Avrami exponent and its corresponding crystallization fraction decrease with increasing heating rate except for the BMG (x = 1.32 at.%). The fragility indexes are 32–48 for the studied Zr-based BMGs. The present results are of guiding significance for preparing the excellent BMG composites by heat treatment and selecting suitable conditions for forming the BMGs.

Inheritance of progoitrin and total aliphatic glucosinolate concentrations were investigated in oilseed rape, using parental, F1, F2 and first backcross generations, derived from a cross between resynthesized spring rape and a double-low spring rape cultivar. Progoitrin and total aliphatic glucosinolate concentrations were measured in mature seeds of single plants from these generations, using micellar electrokinetic capillary chromatography. For progoitrin, an additive/dominance model of gene action adequately explained the variation among the generation means, but for total aliphatic glucosinolate concentration, non-allelic interactions were also detected. Predictions based on estimates of the genetic parameters indicated that recombinant inbred lines, rather than second cycle hybrids, appeared to offer a better prospect of reducing glucosinolate concentrations in this material. Estimates of the minimum number of genes controlling these two characters were broadly in line with the number required for the known stages of their biosynthesis.

With the advent of Ensemble methods for Assisted History Matching of reservoir models, it has become increasingly common to use initial ensembles of reservoir models consisting of a fixed (certain) grid geometry and variable (uncertain) 3D facies distributions and 3D petro‐physical property distributions conditional upon facies. In such process, 3D facies realizations are often derived by modifying facies boundary locations around certain known 3D features (often from seismic interpretation). In the context of a fixed grid, distributions of petro‐physical parameters are biased because all the models in the initial ensemble are such that facies boundaries are located at grid boundary locations; in reality, the facies boundary can be located anywhere, and the petro‐physical properties of cells containing facies boundaries differ from strictly facies‐dependent statistics. The bias results, typically, in excessive variance of petro‐physical parameters in initial ensembles in cells which possibly belong to different facies. Such variance bias has detrimental consequences on iterative inversion processes, incrementally introducing a cumulative error on the match term. A 3D Facies Boundary Filter has been developed to statistically correct this bias over ensembles of initial models. The filter relies on the construction of a refined grid and simple averaging of petro‐physical properties and is based on a hypothesis of piecewise linearity of facies boundaries between cell centres. In any ensemble approach, a filtered ensemble would be used to compute unbiased updates and such updates applied upon un‐filtered ensembles. The filter helps obtain better matched models (closer to initial ensemble and/or, in synthetic cases, the truth) and ultimately determines better performance forecast. The bias will be illustrated through a simple 1D example, a 3D synthetic dataset and a real 3D field model. The principle of the filter will be detailed. The impact of the filter on the petro‐physical statistics will be illustrated as well as its impact within the context of EnKF Assisted History Match.

A four-layer feed-forward back-propagation artificial neural network (ANN) is applied to weather radar echo maps of reflectivity data for the prediction of heavy rainfall events in the short-range of 1 to 2 hours. Inputs for the ANN are the cross correlations of statistical measures of a sequence of radar images. The ANN is trained to capture increasingly organized echo patterns that often are preludes to localized heavy rain. Results show that the ANN is able to achieve a success rate of 89% against a false alarm rate of 33%. In parallel, a separate module utilizing Hough transform is developed to depict the lining up of echoes on the reflectivity maps. The module provides an objective analysis tool for forecasters to test the hypothesis that crossing or merging of echo lines, the so-called "X" patterns, would lead to enhanced convection at preferred locations. Working in tandem, the ANN helps to isolate specific sectors on the radar maps where organization is taking place so that the Hough transform module (HTM) can be meaningfully applied in the appropriate target areas. In turn, parameters derived from the HTM, along with the standard statistical measures, can be fed back into the ANN for further training and system enhancement in the identification of "X" patterns.

An algorithmic analog-to-digital conversion technique is described which is capable of achieving high-resolution conversion without the use of matched capacitors in an MOS technology. The exact integral multiplication of the signal required by the conversion is realized through an algorithmic circuit method which involves charge summing with an MOS integrator and exchange of capacitors. A first-order cancellation of the charge injection effect from MOS transistor switches is attained with a combination of differential circuit implementation and an optimum timing scheme. An experimental prototype has been fabricated with a standard 5-/spl mu/m n-well CMOS process. It achieves 12-bit resolution at a sampling rate of 8 kHz. The analog chip area measures 2400 mils/SUP 2/.

A single-source, vacuum vapor deposition technique was used to grow epitaxial (0001) CdS films on (112) CuInSe 2 single crystal substrates. Highly uniform single crystal CdS films up to 16 μm thick were produced and their quality assessed by x-ray diffraction, scanning electron microscopy, and electrical characterization.

The electrical resistivity, the Hall coefficient, and Hall mobility of Zn-doped ZnO single crystals have been measured from 4.2 to 300 K. Excess Zn has been introduced by controlled high temperature heat treatments in a Zn atmosphere. The donor levels and the concentration of donors and acceptors are calculated by a best fit to the data at the higher temperature range. Lattice scattering is the dominant mechanism at the upper temperature range of the measurements. At the intermediate temperature range the ionized and neutral defect scattering mechanisms dominate. Donor band conduction is observed at the lowest temperatures.