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991.
Malek Taher Maghsoodlou Nourollah Hazeri Sayyed Mostafa Habibi Khorassani Ghasem Marandi Mahmoud Nassiri 《Journal of heterocyclic chemistry》2006,43(2):481-484
992.
Mostafa Bendahmane 《Nonlinear Analysis: Theory, Methods & Applications》2010,73(8):2489-2503
In this paper, we are concerned with a system of nonlinear partial differential equations modeling a predator-prey system with cross-diffusion in heterogeneous habitats. Predators are assumed to feed on preys with a Holling type II functional response to prey density and preys are assumed to follow a logistic growth in the absence of predation. The mobility of each classes is assumed to be influenced by the gradient of other classes. The existence result is proved by means of an approximation system, the Faedo-Galerkin method, and the compactness method. The global existence of classical solutions is proved under certain restrictions on the coefficients. 相似文献
993.
A. A. Ramadan A. A. Abd El‐Mongy A. M. El‐Shabiny A. T. Mater S. H. Mostafa E. A. El‐Sheheedy H. M. Hashem 《Crystal Research and Technology》2009,44(1):111-116
The problem of structure investigation of thin films using laboratory XRD diffraction intensities was discussed as a matter of debate. Is the variation in relative intensities of the diffraction patterns due to crystallographic preferred orientation, lattice defects or both? The answer to this question shows a discrepancy in the literatures. The present work is an attempt to propose a possible approach to judge the most probable answer. Thin films of SnO2 were prepared by spray pyrolysis technique using solution of different SnCl2 concentrations (molarity); at fixed substrate temperature and deposition time. The theoretically calculated integrated intensities together with the experimentally obtained and calculated XRD data (relative intensities, texture coefficients and profile analysis) were considered together in order to get the proper picture of the structure characteristics of the prepared films. The complete picture can be assembled by integration and correlation of all the crystallographic information that are extracted from the diffraction pattern including not only the observed intensities but also the size/strain analysis and lattice parameters. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
994.
M. Mostafa M. A. El-Absy M. Amin M. A. El-Amir A. B. Farag 《Journal of Radioanalytical and Nuclear Chemistry》2010,285(3):579-588
Potassium nickel hexacyanoferrate(II) matrix was prepared and characterized. Purification of neutron-activation 99Mo–molybdate(VI) solutes from some residual cross-contaminant radionuclides including 134Cs, 86Rb, 124Sb, 60Co and 51Cr was carried out onto small chromatographic columns of the matrix (each of 1.0 g). Gamma-ray spectrometric analysis data showed that the purification process was not affected by either Mo(VI) concentrations (0.13 and 0.02 M Mo) in the feeding solution of 3.5 M NaNO3 at pH 9.5 or flow rates (0.2 and 5.0 mL/min) at room temperature. Molybdenum(VI) average loss onto the column matrix did not exceed 7.7 × 10?2 mmol Mo. Except for 51Cr, the matrix has very high selectivity for 134Cs, 86Rb and 124Sb with ~50% 60Co elimination. The obtained data were briefly discussed. 相似文献
995.
Aliphatic and aromatic alcohols are efficiently oxidized to ketones or carboxylic acids using aqueous hydrogen peroxide as an oxidant in the presence of a Mn(III) Schiff-base complex as a catalyst under solvent-free conditions. The oxidation of alcohols occurred at 50 °C to give the corresponding ketones or carboxylic acids with a yield higher than 60%. 相似文献
996.
997.
Trace analysis of chlorobenzenes in water samples using headspace solvent microextraction and gas chromatography/electron capture detection 总被引:2,自引:0,他引:2
In the present work, a rapid method for the extraction and determination of chlorobenzenes (CBs) such as monochlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene and 1,2,4-trichlorobenzene in water samples using the headspace solvent microextraction (HSME) and gas chromatography/electron capture detector (ECD) has been described. A microdrop of the dodecane containing monobromobenzene (internal standard) was used as extracting solvent in this investigation. The analytes were extracted by suspending a 2.5 μl extraction drop directly from the tip of a microsyringe fixed above an extraction vial with a septum in a way that the needle passed through the septum and the needle tip appeared above the surface of the solution. After the extraction was finished, the drop was retracted back into the needle and injected directly into a GC column. Optimization of experimental conditions such as nature of the extracting solvent, microdrop and sample temperatures, stirring rate, microdrop and sample volumes, the ionic strength and extraction time were investigated. The optimized conditions were as follows: dodecane as the extracting solvent, the extraction temperature, 45 °C; the sodium chloride concentration, 2 M; the extraction time, 5.0 min; the stirring rate, 500 rpm; the drop volume, 2.5 μl; the sample volume, 7 ml; the microsyringe needle temperature, 0.0 °C. The limit of detection (LOD) ranged from 0.1 μg/l (for 1,3-dichlorobenzene) to 3.0 μg/l (for 1,4-dichlorobenzene) and linear range of 0.5–3.0 μg/l for 1,2-dichlorobenzene, 1,3-dichlorobenzene and from 5.0 to 20.0 μg/l for monochlorobenzene and from 5.0 to 30 μg/l for 1,4-dichlorobenzene. The relative standard deviations (R.S.D.) for most of CBs at the 5 μg/l level were below 10%. The optimized procedure was successfully applied to the extraction and determination of CBs in different water samples. 相似文献
998.
Laser photothermal therapy of cancer with the use of gold nanoparticles immunotargeted to molecular markers on the cell surface has been shown to be an effective modality to selectively kill cancer cells at much lower laser powers than those needed for healthy cells. To elucidate the minimum light dosimetry required to induce cell death, photothermal destruction of two cancerous cell lines and a noncancerous cell line treated with antiepidermal growth factor receptor (anti-EGFR) antibody-conjugated gold nanoparticles is studied, and a numerical heat transport model is used to estimate the local temperature rise within the cells as a result of the laser heating of the gold nanoparticles. It is found that cell samples with higher nanoparticle loading require a lower incident laser power to achieve a certain temperature rise. Numerically estimated temperatures of 70-80 degrees C achieved by heating the gold particles agree well with the measured threshold temperature for destruction of the cell lines by oven heating and those measured in an earlier nanoshell method. Specific binding of anti-EGFR antibody to cancerous cells overexpressing EGFR selectively increases the gold nanoparticle loading within cancerous cells, thus allowing the cancerous cells to be destroyed at lower laser power thresholds than needed for the noncancerous cells. In addition, photothermal therapy using gold nanoparticles requires lower laser power thresholds than therapies using conventional dyes due to the much higher absorption coefficient of the gold nanoparticles. 相似文献
999.
Amir Jangizehi Mostafa Ahmadi Sebastian Seiffert 《Journal of Polymer Science.Polymer Physics》2019,57(18):1209-1223
The dynamic mechanical properties of supramolecular associative polymer networks depend on the average number of entanglements along the network‐forming chains, Ne, and on their content of associative groups, f . In addition, there may be further influence by aggregation of the associative groups into clusters, which, in turn, is influenced by the chemical structure of these groups, and again by Ne and f of the polymer. Therefore, the effects of these parameters are interdependent. To conceptually understand this interdependency, we study model networks in which (a) Ne, (b) f , and (c) the chemical structure of the associative groups are varied systematically. Each network is probed by rheology. The clustering of the associative groups is assessed by analyzing the rheological data at the end range of frequency covered and by comparison of the number of supramolecular network junctions with the maximum possible number of binary transient bonds. We find that if the total number of the network junctions, which can be formed either by interchain entanglement or by interchain transient associations, is greater than a threshold of 13, then the likelihood of cluster formation is high and the dynamics of supramolecular associative polymer networks is mainly controlled by this phenomenon. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 1209–1223 相似文献
1000.
Zare Abdolkarim Sadeghi-Takallo Masoud Karami Mostafa Kohzadian Alireza 《Research on Chemical Intermediates》2019,45(5):2999-3018
Research on Chemical Intermediates - A novel mesoporous nanomaterial, namely nano-N,N,N′,N′-tetramethyl-N-(silica-n-propyl)-N′-sulfo-ethane-1,2-diaminium chloride... 相似文献