Results For Boron Research Articles

Micronutrient and sodium foliar contents of yellow passion plants as a function of biofertilizers

Introduction. Mineral status related to micronutrients and sodium is important to obtain high yields, despite the fact that no standardized contents have been established for yel- low passion fruit. Biofertilizers have emerged as an important component of the integrated nutrient supply system aiming at an environmentally better nutrient supply because they have a direct action on micronutrient uptake. In this context, the objective of our research was to eva- luate the micronutrient and sodium foliar contents of yellow passion fruit plants fertilized with two different biofertilizers in Brazil. Materials and methods. A randomized block design with treatments distributed in a factorial arrangement (2 × 5) referring to two biofertilizers (simple and enriched with Zn, Mg, Mn, Cu, Co, Fe, Ca, B and Mo) and five doses of each biofertilizer ((0.0, 0.6, 1.2, 1.8 and 2.4) L·plant -1 ) was adopted. Results of boron, copper, iron, manganese, zinc and sodium foliar contents were submitted to variance analysis, the Tukey test and regres- sion analysis. Results and discussion. The results indicate that enriched biofertilizer promoted the statistically highest foliar contents of all elements. The biofertilizer doses applied had dif- ferent effects on foliar contents of the elements studied. Conclusion. Micronutrient and sodium foliar contents of yellow passion fruit were affected by both the type and doses of biofertilizers. Simple biofertilizer promoted optimum supplies of boron and iron, while enriched biofertilizer supplied boron, iron, manganese and zinc. Brazil / Passiflora edulis / fertilizer application / biofertilizers / mineral content / leaves / tissue analysis

Dopant Diffusion in SiGeC Alloys

In this paper, we discuss the impact of germanium and carbon on the diffusion of common dopants in Si-based alloys. We review results of various diffusion experiments and discuss the basic physical mechanisms of the observed changes of diffusion coefficients as a function of alloy composition. Results of boron and phosphorus marker layer diffusion experiments are presented for binary Si1-xGex and Si1-yCy and ternary Si1-x-yGexCy alloys.

Charged particle activation analysis of light elements at sub-ppb level

We have developed charged particle activation analysis to determine light elements at a sub-ppb level. This analytical method is characterized by sample bombardment with charged particles at a few tens of mA and substoichiometric separation for13N,11C and18F within two half-life times and with decontamination factors of more than 108. Nuclear reactor interference is also estimated with this method. This analytical method is confirmed to be useful for characterizing highly purified materials from analytical results for boron, carbon, nitrogen and oxygen in Nb refined by the floating zone melting method.

Comparative Study of Simultaneous Implant Activation and Borophosphosilicate Glass (BPSG) Reflow During Rapid Thermal Processing (RTP) and Furnace Annealing on Complex Topographies

ABSTRACTBorophosphosilicate glass (BPSG) is an essential insulating material used to modify thecomplex topography of highly dense, next generation dynamic random access memory (DRAM)devices. The shallow junctions in 16 and 64 Meg DRAMs can only be maintained by severely restricting the time, temperature, and atmosphere of all thermal process steps following the junction implant.In this paper we present the results of rapid thermal process (RTP) assisted reflow of BPSG over complex topographies and compare the results of RTP to furnace reflow in both dry and wet ambients. We also compare the out-diffusion of boron and phosphorous from BPSG films during the RTP and furnace reflow. We found an optimum RTP cycle that completely removes voids in the vicinity of overhang geometries and provides sufficient activation of the underlying dopants (as compared to a furnace reflow and activation cycle). In this study we used the results of boron and phosphorous profile redistribution, underlying dopant activation, and the amount of reflow to compare RTP and furnace processing techniques.

Lattice dynamics of LaB6 studied by ion channeling: La in the Einstein model.

The lattice dynamics of ${\mathrm{LaB}}_{6}$ were studied between 35 and 500 K with use of 0.9-MeV proton channeling. The results of boron were correctly described in the framework of the Debye model, whereas the Einstein model was used to analyze those for lanthanum. The Einstein temperature deduced from the fit was consistent with values provided by other techniques. No evidence for anharmonic potential was found for the lanthanum. Consequently we make the suggestion that the low-temperature specific-heat anomalies of ${\mathrm{LaB}}_{6}$ could have an electronic origin.

DC Arc Plasma Emission Spectrometric Determination of Boron in Plants

Abstract A dc arc plasma emission method is described for determining boron in plants at levels of ≧2.5 ≧g/g. The sample is wet-digested and analyzed at 2497.73A. Lithium is added to mask enhancement of emission by other alkali metals. Results for boron determined by the described method and atomic absorption spectrophotometry compared favorably. Recoveries of boron added to plants ranged from 90.4 to 104.4% with a mean recovery of 99.7%. The described method is convenient, rapid, and accurate for determining boron in plants.

Graphite Fibre-Epoxy Matrix Interface Interactions

Abstract Studies of fibre-epoxy resin matrix model composites show that the “tensile debond” test is not applicable to carbon or graphite fibres. Fibre fracture occurs under the compression strains involved relieving interface stresses and precluding subsequent debond. Calculated minimum bond strengths for pitch-based graphite fibres are similar to results for boron and glass fibres. Interfacial failure is obtained with the “shear debond” test for low and intermediate modulus graphite fibres, but compression fracture also occurs first with high modulus fibres. Pitch-based graphite fibres show a decreasing adhesive interaction with epoxy resin the more oriented the fibre, but results compare favorably with those of other fibres. Surface characterisation shows that all pitch-based graphite fibres exhibit a surface-oriented skin, although surface roughness increases with fibre modulus. The fibres all exhibit similar apparent surface energy characteristics which suggests that wettability does not play a signi...

Vibrational absorption of carbon and carbon-oxygen complexes in silicon

Vibrational absorption of isolated carbon and carbon-oxygen complexes has been studied in silicon containing various carbon isotopes. The energies of the isolated carbon fundamentals and second harmonics have been determined at 290° and 77°K and compared with the corresponding results for boron. The strength of the local mode absorption has been remeasured and the high value of η 0 ≅ 2.5 e has been confirmed. A search has been made for band mode absorption due to carbon with essentially negative results; this fits in with current theoretical ideas on long range impurity induced polarization effects in silicon. Satellite lines near the carbon fundamental at 588, 640 and 690cm −1 for 12C and corresponding lines for 13C and 14C have been correlated in strength with satellite lines at 1104 and 1052cm −1. The latter lines show no splitting or broadening at 4.2°K when different carbon isotopes are present and it is concluded that they are due to vibrations of oxygen in a centre where the rotational motion is quenched. Detailed models of possible C-O pair structures are discussed and compared with isolated oxygen and Li-O centres. It is concluded that the carbon atom in the pair probably occupies a second or third neighbour site to the interstitial oxygen.