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951.
Ismail M. Ali 《Journal of Radioanalytical and Nuclear Chemistry》2010,285(2):263-270
A series of rare-earth-doped sodium titanates with the chemical formula R
x
H
y
Na4 − (x+y)TiO4·nH2O (where R = Ce3+, Nd3+ and Sm3+) were grown employing solid-state fusion reaction technique. The physico-chemical investigations indicated that the new materials
were self engineered into large particles enough to be used in sorption process and having crystalline structures containing
localized Na+ ions. Equilibrium studies revealed that an enhancement in sorption efficiency of sodium titanate after rare-earth doping.
The neodymium-rich sodium titanate exhibited a better exchange affinity for Cs+ compared to the other studied series. Data on the kinetics of cesium exchange fit well to pseudo-second order and intra-particle
diffusion models. In a separate experiment, it was reported that the R-HNaTi series showed responsible sorption affinity toward
Ce, Nd and Sm ions in their solution mixture with insignificant selectivity trend which reflects the high stability of titanate
matrices. 相似文献
952.
Fariborz Momenbeik Mostafa Roosta Ali Akbar Nikoukar 《Journal of chromatography. A》2010,1217(24):3770-3773
An environmentally benign and simple method has been proposed for separation and determination of fat-soluble vitamins using isocratic microemulsion liquid chromatography. Optimization of parameters affecting the separation selectivity and efficiency including surfactant concentration, percent of cosurfactant (1-butanol), and percent of organic oily solvent (diethyl ether), temperature and pH were performed simultaneously using genetic algorithm method. A new software package, MLR-GA, was developed for this purpose. The results indicated that 73.6 mM sodium dodecyl sulfate, 13.64% (v/v) 1-butanol, 0.48% (v/v) diethyl ether, column temperature of 32.5 °C and 0.02 M phosphate buffer of pH 6.99 are the best conditions for separation of fat-soluble vitamins. At the optimized conditions, the calibration plots for the vitamins were obtained and detection limits (1.06–3.69 μg mL−1), accuracy (recoveries > 94.3), precision (RSD < 3.96) and linearity (0.01–10 mg mL−1) were estimated. Finally, the amount of vitamins in multivitamin syrup and a sample of fish oil capsule were determined. The results showed a good agreement with those reported by manufactures. 相似文献
953.
954.
Ali Asghar Rastegari Abdol-Khalegh Bordbar Vajihe Mehnati-Najafabadi 《Cellulose (London, England)》2010,17(6):1213-1225
The present study evaluates the binding of cetylpyridinium chloride (CPC) with cellulase in various experimental conditions
using potentiometric, fluorescence spectroscopy and turbidimetric techniques. The analysis of binding curves revealed the
existence of two sets of binding sets for CPC. The binding parameters were estimated and interpreted in terms of structural
viewpoints of cellulase. The observation of turbidity suggests that CPC molecules individually nucleate around cellulase/CMC
complex to form micelle-like structures. Fluorescence spectroscopy analysis of cellulase/CMC-surfactant system showed that
these complexes could be compact to elucidate the mechanism of binding cellulase/CMC complex to CPC. The differential response
of the enzyme/CMC to surfactant, indicates that the interaction on the complex surface is strongly ionic and hydrophobic(cooperative)
in nature. A sequencing analysis was also conducted on β-1, 4-endoglucanase from A. niger (EglA) and others from family 12 in order to examine the nature of interaction involved in binding process and structure
of carbohydrate-protein complexes. The results suggest that the conserved residues are located in a more hydrophobic microenvironment
and apolar area energy is more than polar within enzyme structure. 相似文献
955.
ElShazali Ahmed Mohamed Nahid Abdelraheem Ali Salma Hashim Ahmed Isam A. Mohamed Ahmed Elfadil E. Babiker 《Radiation Physics and Chemistry》2010,79(7):791-796
Whole and dehulled flours of millet cultivars Ashana and Dembi were stored for 30 and 60 days before and after radiation and/or cooking. Phytic acid and polyphenols contents were assayed for all treatments. The results revealed that the storage period was found to have no effect on phytate and polyphenols contents. Moreover, dehulling of the grains reduced more than 50% of phytate and polyphenols of both cultivars. Cooking of the raw whole and dehulled flour significantly (P≤0.05) reduced phytate and polyphenols contents for both cultivars. Radiation process alone had no effect on phytate and polyphenols contents but when followed by cooking significantly (P≤0.05) reduced the level of such antinutrients for the whole and dehulled flour of both cultivars. Dehulling alone significantly (P≤0.05) decreased Ca and P content but slightly decreased Fe content. Radiation alone or in combination with cooking was found to have slight effect on minerals content of the whole and dehulled raw flour for both cultivars. Cooking alone or in combination with radiation of whole or dehulled raw flour significantly (P≤0.05) improved the extractable Ca but had no significant (P≤0.05) effect on extractable P and Fe for both cultivars. 相似文献
956.
Ali Haider Zareen Akhter Humaira Masood Siddiqi Edward R. T. Tiekink 《Journal of chemical crystallography》2010,40(5):397-401
Abstract
The molecule of 4-aminobenzohydrazide is essentially planar and geometric parameters conform to literature precedents. Supramolecular N–H···O and N–H···N interactions combine to link molecules of 4-aminobenzohydrazide into a three-dimensional network. Weaker N–H···N and N–H···π interactions consolidate the structure. The compound crystallizes in the monoclinic space group P21/n with a = 5.411(2) ?, b = 14.000(6) ?, c = 9.894(4) ?, β = 103.917(7)o, and Z = 4. 相似文献957.
采用初湿浸渍和溶胶凝胶法分别制备了Li/MgO催化剂和Li/MgO纳米催化剂. 比较两种Li/MgO催化剂对于甲烷氧化偶联反应的催化性能. 采用X射线衍射、BET吸附和透射电镜进行了表征.在973-1073 K和总压力为101 kPa下对催化剂进行了测试. 实验结果表明,Li/MgO纳米催化剂比普通催化剂对于甲烷氧化偶联反应表现为更高的甲烷转换率,较高选择性和较高的的主要产品(乙烷和乙烯)的产率. 相似文献
958.
A series of Zn(II)-Schiff bases I, II and III complexes were synthesized by reaction of o-phenylenediamine with 3-methylsalicylaldehyde, 4-methylsalicylaldehyde and 5-methylsalicylaldehyde. These complexes were characterized using FT-IR, UV-Vis, Diffuse reflectance UV-Vis, elemental analysis and conductivity. Complex III was characterized by XRD single crystal, which crystallizes in the triclinic system, space group P-1, with lattice parameters a?=?9.5444(2) Å, b?=?11.9407(2) Å, c?=?21.1732(3) Å, V?=?2390.24(7) Å3, D c ?=?1.408 Mg m?3, Z?=?4, F(000)?=?1050, GOF?=?0.981, R1?=?0.0502, wR2?=?0.1205. Luminescence property of these complexes was investigated in DMF solution and in the solid state. Computational study of the electronic properties of complex III showed good agreement with the experimental data. 相似文献
959.
Loredo A Plessy A El Hafidi A Hamzaoui N 《The Journal of the Acoustical Society of America》2011,129(4):1905-1918
A numerical vibroacoustic model that can manage multilayered plates locally covered with damping patches is presented. All the layers can have an on-axis orthotropic viscoelastic behavior. Continuity of displacements and transverse shear stresses at each interface is enforced, which permits to write the entire displacement field in function of the displacements of the--common--first layer, leading to a two-dimensional plate model. The problem is then discretized by Rayleigh-Ritz's method using a trigonometric basis that includes both sine and cosine functions in order to treat various boundary conditions. The excitation can be of mechanical kind (concentrated or distributed forces) or of acoustic kind (plane wave of any incidence, diffuse field, etc.). The model permits to compute different vibroacoustic indicators: the mean square velocity of the plate, the radiation efficiency, and the transmission loss. Comparisons between the present model and numerical results from literature or finite element computations show that the model gives good results in both mechanical and acoustical aspects. Then, a comparison of the effects of different distributions of patches is presented. The role of the surface covering rate is first discussed, followed by a study involving different geometries for the same surface covering rate. 相似文献
960.
Seyed Ali Salehizadeh Dariush Souri 《Journal of Physics and Chemistry of Solids》2011,72(11):1381-1385
The glass transition temperature dependence to heating rate and therefore the activation energy (ΔH?) of the glass transition of (60-x)V2O5–xNiO–40TeO2 oxide glasses with 0≤x≤20 (in mol%) were investigated at heating rates φ (=3 6, 9, 10 and 12 K/min) using differential scanning calorimetry (DSC). The heating rate dependence of Tg was used to investigate the applicability of different theoretical models describing the glass transition. Using the application of Moynihan and Kissinger et al. models to the present data, different values of (ΔH?) at each different heating-rate regions were obtained. The fragility parameter (m=ΔH?/R Tg) was ∼24.98 for x=10 mol%, suggesting that this glass may be considered as a rather strong glass (fragility index m∼>20 is an indication of fragile glass). Also the compositional dependence of Tg and ΔH? was investigated. 相似文献