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The study of the oligosaccharides extracted from Tephrosia purpurea seeds was undertaken using the instant controlled pressure drop (DIC) as a pre-treatment prior to conventional solvent extraction. This DIC procedure provided structural modification in terms of expansion, higher porosity and improvement of specific surface area; diffusion of solvent inside such seeds and availability of oligosaccharides increase notably. In this paper, we investigated and quantified the impact of the different DIC operative parameters on the yields of ciceritol and stachyose extracted from T. purpurea seeds. The treatment could be optimized with a steam pressure (P) (P=0.2 MPa), initial water content (W) (W=30% dry basis (DB)) and thermal treatment time (t) (t=30s). By applying DIC treatment in these conditions, the classic process of extraction was intensified in both aspects of yields (145% of ciceritol and 185% of stachyose), and kinetics (1h of extraction time instead of 4h for conventional process). The scanning electron microscopy micrographs provided evident modifications of structure of seeds due to the DIC treatment. 相似文献
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The optical limiting performance of Sudan III dye doped into ethylene propylene diene polymethylene polymer (EPDM) is investigated using 532 nm, 10 ns pulses from a frequency-doubled Nd-YAG laser. The optical limiting behavior is investigated by transmission measurement through the sample at different concentrations. Our results show that the optical limiting efficiency is concentration dependent. 相似文献
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The general formula for the number of diagrammatic terms occurring in the Tn equation within a particular coupled cluster model is derived. Both the antisymmetrized and Goldstone diagrams are considered. In addition to the full coupled cluster equation approximate approaches are discussed, and for each the general formula for the number of terms is given. Analogous expressions are presented for the number of diagrammatic terms contributing to the elements of the transformed Hamiltonian [Hbar] = e?T HeT . 相似文献
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M.D. Zidan M.B. Alsous A.W. Allaf A. Allahham A. AL-Zier 《Optics & Laser Technology》2012,44(7):2282-2285
The optical limiting action of C60 doped poly(ethylacetylenecarboxylate) polymer has been carried out using Pulse Nd-YAG laser at 532 nm as the source of excitation. The optical limiting measurements were performed at three different doping concentrations. The optical limiting efficiency of the C60 doped poly(ethylacetylenecarboxylate) polymer was studied at various doping concentrations, the threshold limiting fluence at 0.15 J/cm2 was observed with transmission of about 89%. An explanation based on the combination of two-photon absorption and reverse saturable absorption was proposed for its nonlinear optical absorption behavior. 相似文献
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Allaf AW Ajji Z 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2000,56(10):1971-1977
Antimony oxide trihalides, SbOX3 molecules, where X = F or Cl have been produced, by means of an on-line process, using antimony trichloride, SbOCl3 as starting material passed over heated silver oxide at 230 degrees C. The antimony oxide trichloride SbOCl3 formed is then reacted with sodium fluoride, NaF at 550 degrees C to produce antimony oxide trifluoride, SbOF3. The products have been characterized by the IR spectra of their vapors. Low resolution gas-phase Fourier transform infrared spectra show strong bands centered at 1272 and 1217 cm(-1), assigned to nu1(a1), the O=Sb stretching fundamental of SbOF3 and SbOCl3, respectively. Both observed bands show typical PQR-type structure with a strong Q-head. 相似文献
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Baya Berka-Zougali Aicha Hassani Colette Besombes Karim Allaf 《Journal of chromatography. A》2010,1217(40):6134-6142
In the present work, the new extraction process of Détente Instantanée Contrôlée DIC (French, for instant controlled pressure drop) was studied, developed, quantitatively and qualitatively compared to the conventional hydrodistillation method for the extraction of essential oils from Algerian myrtle leaves. DIC was used as a thermomechanical treatment, DIC subjecting the product to a high-pressure saturated steam. The DIC cycle ends with an abrupt pressure drop towards vacuum, and this instantly leads to an autovaporization of myrtle volatile compounds. An immediate condensation in the vacuum tank produced a micro-emulsion of water and essential oils. Thus, an ultra-rapid cooling of residual leaves occurred, precluding any thermal degradation. An experimental protocol was designed with 3 independent variables: saturated steam pressure between 0.1 and 0.6 MPa, resulting in a temperature between 100 and 160 °C, a total thermal processing time between 19 and 221 s, and between 2 and 6 DIC cycles. The essential oils yield was defined as the main dependent variable. This direct extraction gave high yields and high quality essential oil, as revealed by composition and antioxidant activity (results not shown). After this treatment, the myrtle leaves were recovered and hydrodistilled in order to quantify the essential oil content in residual DIC-treated samples. Scanning electron microscope (SEM) showed some modification of the structure with a slight destruction of cell walls after DIC treatment. 相似文献
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M.D. Zidan M.B. Alsous A.W. Allaf A. Allahham A. AL-Zier 《Optics & Laser Technology》2011,43(7):1343-1346
The optical limiting action of poly(dimethylacetylendicarboxylate) polymer doped with fullerene C60 has been investigated under irradiation with 10 ns laser pulses at 532 nm. The optical limiting measurements were performed at four different dopant concentrations. The threshold limiting fluence at 0.3 J/cm2 was observed at high doping concentrations, with transmission of about 55%. An explanation based on the combination of two-photon absorption and reverse saturable absorption was proposed for its nonlinear optical absorption behavior. 相似文献
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In this paper the generation of harmonic waves in an elastic magneticmaterial, which is a perfect conductor of electricity, isconsidered. It has been assumed that an infinite body is subjected tothe action of an initially constant magnetic fieldH = (H,0,0) and in the plane ax+by=0 acts a source ofdistortion. It has been shown that this source may produce bothtransverse and longitudinal waves and each of them consists of two parts,which propagate with different speeds. The amplitudes and speeds in dependence on theangle between the direction of wave propagation and the magnetic fieldintensity H have been discussed. 相似文献