排序方式: 共有68条查询结果,搜索用时 31 毫秒
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Hassan A. Zedan M. Alghamdi Seham Sh. Tantawy 《Mathematical Methods in the Applied Sciences》2015,38(17):4357-4364
We study in this paper the Q‐symmetry and conditional Q‐symmetries of Drinfel'd–Sokolov–Wilson equations. The solutions which we obtain in this paper take the form of convergent power series with easily computable components. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Andy K. W. Ma Ali A. Alghamdi Kassem Tofailli Nicholas M. Spyrou 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(2):353-357
Early detection of the red palm weevils (RPW) is a major challenge in agriculture among all kinds of palm trees due to the
nature of the insect and the difficulty to trace them through their life stages associated with the tree life. Many methods
have been applied for the weevil detection such as X-ray diffraction techniques, fluoroscopy and ultrasound. On the other
hand, the idea of tomography has been used for other purposes such as the determination of the age of the tree and for applied
environmental studies. Such technology can also reveal the weevil in principle. In this study, we explore the use of X-ray
CT for weevil detection with the Monte Carlo method. A model of the stem of a palm tree is developed for simulations. MCNPX
is chosen to carry out the simulations for the radiography tally in the code. The tally records the 2D data of the X-ray beams
irradiating the tree model. An iterative reconstruction method for cone beam CT is applied to obtain the 3D slices of the
tree model. We are exploring the minimum number of projection angles and the detectability of the weevil. We shall also report
the sensitivity of weevil detection using X-ray CT with a large set of simulations with different weevil sizes and tree diameters. 相似文献
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Jing Qin Guohai Liang Bingxi Feng Gen Wang Na Wu Yonghui Deng Ahmed A. Elzatahry Abdulaziz Alghamdi Yongxi Zhao Jing Wei 《中国化学快报》2021,32(2):842-848
Plant polyphenol-based coordination polymers(CPs) with ultra-small particle size and tailorable compositions are highly desired in biomedical applicatio ns,but their synthesis is still challenging due to the sophisticated coordination assembly process and unavoidable self-oxidation polymerization of polyphenol. He rein,a general ligand covalent-modification mediated coordination assembly strategy is proposed for the synthesis of water-dispersible CPs with tunable metal species(e.g., Gd,Cu,Ni,Zn,Fe)and ultra-small diameter(8.6-37.8 nm) using nontoxic plant polyphenol(e.g..tannic acid,gallic acid) as a polymerizable ligand.Polyphenol molecules react with formaldehyde firstly,which can effectively retard the oxidation induced self-polymerization of polyphenol and lead to the formation of metal ions containing CPs colloidal nanoparticles.These ultrafine nanoparticles with stably chelated metal io ns are highly water dispersible and thus advantageous for bioimaging.As an example,ultra-small Gd contained CPs exhibit higher longitudinal relaxivity(r_1=25.5 L mmol ~1 s ~1) value with low r_2/r_1(1.19) than clinically used Magnevist(Gd-DTPA,r_1=3.7 L mmol ~1 s ~1).Due to the enhanced permeability and retention effect,they can be further used as a positive contrast agent for T_1-weighted MR imaging of tumour. 相似文献
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D. G. Beasley A. Alghamdi M. C. Freitas A. Fernandes Z. Révay 《Journal of Radioanalytical and Nuclear Chemistry》2009,281(2):307-311
The epithermal beamline at the Portuguese Research Reactor is being optimized for Prompt Gamma Neutron Activation Analysis
(PGNAA). One of the major changes is to thermalise the beam by the introduction of a sapphire crystal into the beamline. Placing
the sapphire at the exit of the beamline would greatly reduce the alterations and work necessary to the port and make the
crystal easily removable. However, the scattered neutrons from the sapphire would increase both the neutron-induced detector
damage and the background radiation. MCNPX was used to simulate the crystal in the beam port and at the exit of the port. 相似文献
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Ahmad H. Alghamdi 《Arabian Journal of Chemistry》2010,3(1):1-7
Stripping voltammetric techniques are powerful analytical tools that are becoming widely used in various chemical analysis fields. Hence, the objective of this survey is to give a general overview on the scope of the applicability of stripping voltammetric methods in food industries. The applications discussed include recent studies on the utilization of these electroanalytical methods in determination of food contaminants (toxic metals, pesticide, fertilizers and veterinary drugs residuals), trace essential elements, food additive dyes and other organic compounds of biological significance. Tables that give method summaries referenced to the original work are provided. 相似文献
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A. A. Alghamdi J. Al-Mokhlef A. Alhaj N. M. Spyrou 《Journal of Radioanalytical and Nuclear Chemistry》2007,271(3):783-787
The technique of photon activation analysis (PAA) is widely employed in many fields as an effective non-invasive tool for
measuring elemental compositions and concentrations. In recent years there has been a revival and growing interest of PAA
in general and for medical applications in particular. The feasibility of using a PET scanner (Ecat Exact 931) to determine
nitrogen concentration in a dead rabbit is described. This method is based on the photon activation of 14N(γ,n)13N (T
1/2 = 9.9 min) using an 18 MV photon beam Medical Linear Accelerator (Varian 2300EX). 相似文献
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Waseem Sharaf Saeed Hamad Abdullah Al-Lohedan Abdel-Basit Mohammed Al-Odayni Abdulaziz Ali Alghamdi Ahmad Abdulaziz Al-Owais 《Journal of Dispersion Science and Technology》2019,40(1):128-139
An n-butyl bromide/sodium dodecyl sulfate/n-butanol/water microemulsion system was chosen as a model of an organohalide-containing microemulsion. Two systems were prepared using the Bourayne method: a water-rich system and an n-butyl-bromide-rich system. The destabilization of this micro-organized system and the phase separation were investigated. This microemulsion, in which the oil phase in the feed is the lower layer, was successfully destabilized using the pervaporation technique with polydimethylsiloxane and poly(vinyl alcohol) membranes. In this way, different factors governing the separation process were investigated such as the mass transfer and the effect of time and operating temperature on the microemulsion destabilization. 相似文献
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Abeer Alghamdi Thorben Wellbrock Prof. David J. S. Birch Dr. Vladislav Vyshemirsky Dr. Olaf J. Rolinski 《Chemphyschem》2019,20(23):3181-3185
A non-invasive intrinsic fluorescence sensing of the early stages of Alzheimer's beta amyloid peptide aggregation in the presence of copper ions is reported. By using time-resolved fluorescence techniques the formation of beta amyloid-copper complexes and the accelerated peptide aggregation are demonstrated. The shifts in the emission spectral peaks indicate that the peptides exhibit different aggregation pathways than in the absence of copper. 相似文献
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Anh N. Hong Diana Luong Mohammed Alghamdi Wei-Cheng Liao Weiyi Zhang Emily Kusumoputro Yichong Chen Prof. P. Alex Greaney Prof. Yongtao Cui Prof. Jing Shi Prof. Xianhui Bu Prof. Boniface P. T. Fokwa Prof. Pingyun Feng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(52):e202201576
Two new rod-packing metal–organic frameworks (RPMOF) are constructed by regulating the in situ formation of the capping agent. In CPM-s7, carboxylate linkers extend 1D manganese-oxide chains in four additional directions, forming 3D RPMOF. The substitution of Mn2+ with a stronger Lewis acidic Co2+, leads to an acceleration of the hydrolysis-prone sulfonate linker, resulting in presence of sulfate ions to reduce two out of the four carboxylate-extending directions, and thus forming a new 2D rod-packing CPM-s8. Density functional theory calculations and magnetization measurements reveal ferrimagnetic ordering of CPM-s8, signifying the potential of exploring 2D RPMOF for effective low-dimensional magnetic materials. 相似文献