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1.
We carried out detailed calculations for photorefractive wave-mixing switches based on one of three crystals with high electro-optic coefficients, namely, BaTiO3, Strontium Barium Niobate (SBN (0.75)), and Potasium Sodium Strontium Barium Niobate (KNSBN). A comparison of results for the three crystals shows that a 0_-cut BaTiO3 crystal is suitable for a longitudinal switch and requires a voltage of about 80 for a 2-mm-thick crystal to induce sufficient phase mismatch. The electrodes must be transparent for the incident and diffracted beams. A 45_-cut SBN (0.75) crystal, however, is suitable for a lateral switch and requires a voltage of about 150 for a 1-mm-wide crystal. The electrodes do not need to be transparent. 相似文献
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Raheel A. Imtiaz-ud-Din Taj M. B. Tahir M. N. Al-Shakban M. 《Russian Journal of General Chemistry》2018,88(7):1508-1514
Russian Journal of General Chemistry - Five new substituted benzamide derivatives as ionic solids are prepared and characterized by FT-IR, 1H, and 13C NMR spectroscopy. The crystal structure for... 相似文献
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Ahmed A. El-Asmy Taj Y. Al-Ansi Ragab R. Amin F. M. El-Shahat 《Transition Metal Chemistry》1990,15(1):12-15
Summary Several new complexes of the title ligand (H2MPTS) with CoII, NiII, CuII, and CdII have been prepared. Structural assignments of the complexes have been made based on elemental analysis, molar conductivity, magnetic moment and spectral (i.r.,1H n.m.r., reflectance) studies. The compounds are non-conductors in dimethylsulphoxide. The neutral molecule is coordinated to the metal(II) sulphate as a bidentate ligandvia the two carbonyl groups. The ligand reacts with the metal(II) chlorides with the liberation of two hydrogen ions, behaving as a bianionic quadridentate (NONO) donor. Enolization is confirmed by the pH-titration of H2 MPTS and its metal(II) complexes against NaOH. A distorted octahedral structure is proposed for the CuII complex, while a square planar structure is suggested for both CoII and NiII complexes. The stoichiometry of the complexes formed in EtOH and buffer solutions, their apparent formation constants and the ranges for obedience to Beer's law are reported for CoII, NiII and CuII ions. The ligand pK values are calculated. The antimicrobial activity of H2 MPTS and its CoII, NiII, CuII and MnII complexes is demonstrated. 相似文献
4.
Summary Complexes of CoII, NiII, CuII, ZnII, CdII, HgII and UO
2
II
with benzil bis(4-phenylthiosemicarbazone), H2BPT, have been synthesized and their structures assigned based on elemental analysis, molar conductivity, magnetic susceptibility and spectroscopic measurements. The i.r. spectra suggest that the ligand behaves as a binegative quadridentate (NSSN) (CoII, CuII, HgII and UO
2
II
complexes) or as a binegative quadridentate-neutral bidentate chelating agent (NiII, ZnII and CdII complexes). Octahedral structures for the CoII and NiII complexes and square-planar structure for the CuII complex are suggested on the basis of magnetic and spectral evidence. The crystal field parameters (Dq, B and
B) for the CoII complex are calculated and agree fairly well with the values reported for known octahedral complexes. The ligand can be used for the microdetermination of NiII ions of concentration in the 0.4–6×10–4 mol l–1 range and the apparent formation constant for the species generated in solution has also been calculated. 相似文献
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Carole Diederichs David Taj Thimothe Lecomte Crisitiano Ciuti Philippe Roussignol Claude Delalande Aristide Lemaître Ludovic Largeau Olivia Mauguin Jacqueline Bloch Charles Leyder Alberto Bramati Elisabeth Giacobino Jrme Tignon 《Comptes Rendus Physique》2007,8(10):1198-1204
We report the realization of a monolithic vertical-cavity, surface emitting micro-optical parametric conversion nanostructure, triply resonant with the parametric frequencies, allowing parametric oscillation with ultra-low pump power threshold. The photonic phase-space naturally provides triple resonance for the parametric frequencies, together with built-in cavity phase-matching for the pump wave at normal incidence. Parametric oscillation is observed in both the strong and weak exciton–photon coupling regime, allowing a high operating temperature. Signal and idler beams can be collected at 0° or at finite angles. The OPO threshold is low enough to envisage the realization of an all-semiconductor electrically-pumped micro-parametric oscillator. To cite this article: C. Diederichs et al., C. R. Physique 8 (2007). 相似文献
7.
S. Taj Ph. D. 《Mathematical Methods of Operations Research》1990,34(5):395-410
Mathematical programming models have been developed to find utility maximized nutritious diets. The utility maximized diets have been shown to be more practical, more realistic, and less costly than the non-utility maximized diets. In this study we further increase the desirability of diets by gradually softening those nutrients which have been supplied by the foods in the diet at a cost which is above the market price of the respective nutrient. Marginal analysis is used to find marginal costs of the nutrients. The parametric quadratic programming is used to find the optimum diet where the cost of nutrient is equal to the market price of the nutrient supplement. The resulting diet is more desireable and less costly than the previous diets. 相似文献
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L. Oufni S. Taj B. Manaut M. Eddouks 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(2):403-410
The uptake of 238U and 232Th in different parts of some selected plants used in traditional treatment of hypertension and diabetes in south-eastern
Morocco (Errachidia area) has been studied using two different types of solid state nuclear track detectors (SSNTDs) LR-115
type II and CR-39. Plant uptake of radionuclides is one of many vectors for introduction of contaminants into the human food
chain. Thus, it is critical to understand soil–plant relationships that control nuclide bioavailability. Soil concentrations
of uranium ranged from 6.10 to 11.62 ppm, with a mean of 7.90 ppm. Soil concentrations of thorium ranged from 2.70 to 4.80
ppm, with a mean of 3.41 ppm. Mean uranium specific activities were 8.38 Bq kg−1 in root tissue, 5 Bq kg−1 in stem tissue and 6.02 Bq kg−1 in leaf tissue. Mean thorium specific activities were 2.53 Bq kg−1 in root tissue, 1.64 Bq kg−1 in stem tissue and 1.96 Bq kg−1 in leaf tissue. The transfer factors of 238U and 232Th from soil to different parts (root, stem, leaf, seed and fruit) of studied plant samples have been investigated. The transfer
factors obtained for root plants were markedly higher than those for leaf, stem, fruit and seed plants. Soil-to-plant transfer
factor (TF) is one of the most important parameters to be used in transfer models for predicting the concentration of radionuclides
in agricultural crops and for estimating dose impacts to man. This study of uranium and thorium uptake in plants used in traditional
medicine is also significant as far as the health hazard effects of uranium and thorium in human being are concerned. 相似文献
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