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991.
Priya Malshe Maryam Mazloumpour Ahmed El-Shafei Peter Hauser 《Plasma Chemistry and Plasma Processing》2012,32(4):833-843
In this study, diallyldimethylammonium chloride (DADMAC), a quaternary ammonium salt monomer, is graft polymerized on 50?C50 Nylon-Cotton (NyCo) standard military fabric using atmospheric pressure glow discharge plasma to impart self-detoxification capability. Atmospheric pressure plasma?is used to induce free radical chain polymerization of the DADMAC monomer to introduce a graft polymerized network on the fabric with durable antimicrobial properties. Pentaerythritol tetraacrylate (PETA) is used as a cross-linking agent to obtain a highly cross-linked, durable polymer network. The presence of polyDADMAC on the fabric surface is confirmed using acid dye staining, SEM, and TOF?CSIMS. Antibacterial performance is investigated using standard AATCC Test Method 100 for both gram positive and gram negative bacteria. Results show 99.9?% reduction in the bacterial activities of Klebsiella pneumoniae and Staphylococcus aureus. 相似文献
992.
Simple, accurate and sensitive spectrofluorimetric method has been proposed for the determination of three cephalosporins,
namely; cefixime (cefi), cephalexine (ceph), cefotaxime sodium (cefo) in pharmaceutical formulations. The method is based
on a reaction between cephalosporins with 1, 2-naphthoquinone-4-sulfonic (NQS) in alkaline medium, at pH values of 12.0 for
cefi and 13.0 for ceph and cefo to give highly fluorescent derivatives extracted with chloroform and subsequently measured
at 600,580 and 580 nm after excitation at 520,455 and 490 nm for cefi, ceph and cefo respectively. The optimum experimental
conditions have been studied. Beer’s law is obeyed over the concentrations of 10–35 ng/mL, 10–60 ng/mL and 20–45 ng/mL for
cefi,ceph and cefo, respectively. The detection limits were 2.02 ng/mL, 2.09 ng/mL and 2.30 ng/mL for cefi, ceph and cefo,
respectively, with a linear regression correlation coefficient of 0.9987, 0.9995 and 0.9991 and recoveries in range from 98.5-107.04,
95.17-101.00 and 95.00-109.55% for cefi, ceph and cefo, respectively. This method is simple and can be applied for the determination
of cefi, ceph and cefo in pharmaceutical formulations in quality control laboratories. 相似文献
993.
Aboel‐Magd A. Abdel‐Wahab Omima S. Mohamed Saleh A. Ahmed Mostafa F. Mostafa 《Journal of Physical Organic Chemistry》2012,25(12):1418-1421
The superiority of silver‐doped titania for photocatalytic oxidation (PCO) of organic compounds inspired us to investigate PCO of 1,2‐cyclohexanediol. Ag/TiO2 was prepared, characterized (nanosize 19–24 nm) and used for oxidation of 1,2‐cyclohexanediol (1) in acetonitrile. The photolysate was analyzed using GC and GC/MS techniques. The PCO products are 2‐hydroxylcyclohexanone (2), 1,2‐cyclohexandione (3), 2‐cyclohexenone(4), cyclohexanone (5), and adipic acid (6).The formation of electron–hole pair at the surface of the catalyst followed by oxidation reactions was the suggested mechanism. Kinetic studies revealed first‐order mechanism for PCO of 1 and rate constant (k) = ?0.145 h–1. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
994.
Nasim Ahmed Syed Alwee Aljunid R. Badlishah Ahmad Hilal A. Fadhil Mohd Abdur Rashid 《Optical Review》2012,19(1):1-6
The bit-error rate (BER) performance of the spectral amplitude coding-optical code division multiple access (SACOCDMA) system
has been investigated by using NAND subtraction detection technique with enhanced double weight (EDW) code. The EDW code is
the enhanced version of double weight (DW) code family where the code weight is any odd number and greater than one with ideal
cross-correlation. In order to evaluate the performance of the system, we used mathematical analysis extensively along with
the simulation experiment. The evaluation results obtained using the NAND subtraction detection technique was compared with
those obtained using the complementary detection technique for the same number of active users. The comparison results revealed
that the BER performance of the system using NAND subtraction detection technique has greatly been improved as compared to
the complementary technique. 相似文献
995.
Background model updating is a vital process for any background subtraction technique. This paper presents an updating mechanism that can be applied efficiently to any background subtraction technique. This updating mechanism exploits the color and spatial features to characterize each detected object. Spatial and color features are used to classify each detected object as a moving background object, a ghost, or a real moving object. The starting position of each detected object is the cue for updating background images. In addition, this paper presents a hybrid scheme to detect and remove cast shadows based on texture and color features. The robustness of the proposed method and its effectiveness in overcoming challenging problems such as gradual and sudden illumination changes, ghost appearance, non-stationary background objects, the stability of moving objects most of the time, and cast shadows are verified quantitatively and qualitatively. 相似文献
996.
Mukhtar Ahmed Rana 《Radiation measurements》2012,47(1):50-56
Systematic measurements of swelling of CR-39 nuclear track detector (NTD) due to irradiation with fission fragments and alpha particles over a wide range of fluences from 252Cf are presented here. Precisely designed and optimized exposure and chemical etching experiments were employed to unfold the structure of radiation induced surface damage. Delays in the startup of the chemical etching of latent tracks in low radiation fluence detectors are measured and are found to contain important information about structure of the surface damage. Simple atomic scale pictures of radiation induced surface damage and its chemical etching are developed using measurements of radiation induced swelling of CR-39 detectors and nuclear track parameters. The computer code SRIM2010 was utilized for the calculations of basic features of latent tracks of fission fragments and alpha particles in CR-39. Another computer code TRACK_VISION was used to compute parameters of etched tracks. Computations and experimental findings in the paper coherently compose a realistic picture of radiation damage. 相似文献
997.
Carbonaceous nanomaterials, such as fullerene C60, carbon nanotubes, and their functionalized derivatives have been demonstrated to possess high sorption capacity for organic and heavy metal contaminants, indicating a potential for remediation application. The actual application of these nanomaterials, however, is often hindered by the high cost of materials and the limited understanding of their mobility in porous media. In this work, carbon nano-onions (CNOs), a relatively new addition to the carbonaceous nanomaterials, were synthesized in a cost-effective way using a laser-assisted combustion synthesis process, and carefully characterized for their potential remediation application. Surface oxidized CNOs possessed 10 times higher sorption capacity than C60 for heavy metal ion contaminants including Pb2+, Cu2+, Cd2+, Ni2+, and Zn2+. CNOs aqueous suspension can be very stable in NaCl solution at ionic strength up to 30?mM and CaCl2 solution at ionic strength up to 4?mM CaCl2 when pH ranged from 5 to 9, which are consistent with environmentally relevant conditions. Interactions of CNOs with iron oxide and silica surfaces under favorable condition were found to be electrostatic in origin. Mobility of CNOs in quartz sands was controlled by electrolyte type and concentration. Approximately 4.4, 25.1, and 92.5?% of injected CNO mass were retained in the sand column in ultrapure water, 1?mM?NaCl, and 1?mM CaCl2 solutions, respectively. 相似文献
998.
Raut R Tornow W Ahmed MW Crowell AS Kelley JH Rusev G Stave SC Tonchev AP 《Physical review letters》2012,108(4):042502
The two-body photodisintegration cross section of (4)He into a proton and triton was measured with monoenergetic photon beams in 0.5 MeV energy steps between 22 and 30 MeV. High-pressure (4)He-Xe gas scintillators of various (4)He/Xe ratios served as targets and detectors. Pure Xe gas scintillators were used for background studies. A NaI detector together with a plastic scintillator paddle was employed for determining the incident photon flux. Our comprehensive data set follows the trend of the theoretical calculations of the Trento group very well, although our data are consistently lower in magnitude by about 5%. However, they differ significantly from the majority of the previous data, especially from the recent data of Shima et al. The latter data had put into question the validity of theoretical approaches used to calculate core-collapse supernova explosions and big-bang nucleosynthesis abundances of certain light nuclei. 相似文献
999.
Hassan Yousif Ahmed M. Almaleeh Hilal Fadhil S.A. Aljunid Ammar Elyass N.M. Saad 《Optik》2012,123(15):1352-1359
This paper investigates the performance of vector combinatorial (VC) code for spectral amplitude coding optical code-division multiple-access (SAC-OCDMA) system using a newly proposed subtract exclusive OR detection (SED) technique. VC code is constructed using Euclidean vector and algebraic ways. One of the important properties of this code is that the maximum cross correlation is one, which means that multi-user interference (MUI) and phase induced intensity noise (PIIN) are reduced. The weight for the VC code can be any positive integer number. The system performance was evaluated by comparing the theoretical studies using related equations and simulation results taken from the commercial optical systems, “VPI? TransmissionMaker 7.1”. Significant improvement in system performances has been observed when the proposed SED technique employing VC code was applied compared to other codes that utilize conventional balance detection techniques for spectral amplitude coding. 相似文献
1000.
Ahmed Z Allada K Aniol KA Armstrong DS Arrington J Baturin P Bellini V Benesch J Beminiwattha R Benmokhtar F Canan M Camsonne A Cates GD Chen JP Chudakov E Cisbani E Dalton MM de Jager CW De Leo R Deconinck W Decowski P Deng X Deur A Dutta C Franklin GB Friend M Frullani S Garibaldi F Giusa A Glamazdin A Golge S Grimm K Hansen O Higinbotham DW Holmes R Holmstrom T Huang J Huang M Hyde CE Jen CM Jin G Jones D Kang H King P Kowalski S Kumar KS Lee JH LeRose JJ Liyanage N Long E McNulty D 《Physical review letters》2012,108(10):102001
The parity-violating cross-section asymmetry in the elastic scattering of polarized electrons from unpolarized protons has been measured at a four-momentum transfer squared Q2 = 0.624 GeV2 and beam energy E(b) = 3.48 GeV to be A(PV) = -23.80 ± 0.78(stat) ± 0.36(syst) parts per million. This result is consistent with zero contribution of strange quarks to the combination of electric and magnetic form factors G(E)(s) + 0.517G(M)(s) = 0.003 ± 0.010(stat) ± 0.004(syst) ± 0.009(ff), where the third error is due to the limits of precision on the electromagnetic form factors and radiative corrections. With this measurement, the world data on strange contributions to nucleon form factors are seen to be consistent with zero and not more than a few percent of the proton form factors. 相似文献