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701.
Hadi Kh. Mahabadi Alfred Rudin 《Journal of polymer science. Part A, Polymer chemistry》1979,17(6):1801-1810
The effect of solvent on the termination rate constant Kt, in the initial stages of free radical polymerizations has been estimated by considering its effect on the viscosity of the medium and on the overall dimensions of the macroradicals. The expression derived predicts that Kt is inversely proportional to the viscosity of the reaction medium, η0, and that Kt, increases as the overall dimensions of the radicals decrease in poorer solvents. The effect of solvent on the η0Kt, product depends on the average size and concentration of polymer in the system. For relatively high concentrations of high-molecular-weight polymers η0Kt can be greater in a better solvent than in a poorer solvent. This trend would be reversed for low concentrations and/or low polymer molecular weights. Good agreement has been found between experimental and estimated values of η0Kt. 相似文献
702.
M. Ali A. Islam S. Kar S. K. Biswas D. A. Hadi A. H. Khan 《Journal of Radioanalytical and Nuclear Chemistry》1986,97(1):113-122
The proton particle induced X-ray emission (proton PIXE) technique has been employed to study the heavy element status (essential and toxic) in five different varieties of pulses commonly cultivated and consumed in Bangladesh. In this analysis, the samples were irradiated in air with 2 MeV protons having 30 nA beam intensity for characteristic X-ray excitation. For 40 μC irradiations, the concentration of ten elements (K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Br, and Rb) was determined by comparison with a calibration obtained from the NBS orchard leaf standard, SRM 1571. In a comparative study with atomic absorption spectrophotometric (AAS) measurements of some elements in lathyrus sativus, the data were found to be in good agreement. The results obtained from the present study are discussed and compared with available data. 相似文献
703.
M. Hadi Hadizadeh Yazdi 《Synchrotron Radiation News》2013,26(6):13-14
The 2005 CHESS User Meeting was held on June 14 and 15, 2005, on the campus of Cornell University. A single session occupied the first day, with two concurrent workshops on the second day. The meeting was opened by User Committee member Rob Thorne (Cornell University). CHESS director Sol Gruner began with an overview of the achievements of the most recent running period and the status of the Energy Recovery Linac (ERL), Cornell’s next-generation X-ray photon source project. Quan Hao and Arthur Woll reported on the progress of the Macromolecular Diffraction Facility (MacCHESS) and the G-line, respectively. Don Bilderback gave an account of some of the recent instrumentation developments at CHESS. 相似文献
704.
A series of high quality 1-alkyl-3-methylimidazolium-based ionic liquids are synthesized and used for studying their surface tension. The capillary rise method is used for measuring the surface tension of I−, Cl−, PF6−, and BF4− salts in the temperature range 298–393 K. The capillary apparatus is evacuated and sealed under vacuum. The experimental results show that surface tension of these compounds depend systematically on temperature. 相似文献
705.
706.
In this study, device modeling and simulation are conducted to explain the effects of each layer thickness and temperature on the performance of ZnO/CdS/CIS thin film solar cells. Also, the thicknesses of the CIS and CdS absorber layers are considered in this work theoretically and experimentally. The calculations of solar cell performances are based on the solutions of the well-known three coupling equations: the continuity equation for holes and electrons and the Poisson equation. Our simulated results show that the efficiency increases by reducing the CdS thickness. Increasing the CIS thickness can increase the efficiency but it needs more materials. The efficiency is more than 19% for a CIS layer with a thickness of 2 μm. CIS nanoparticles are prepared via the polyol route and purified through centrifugation and precipitation processes.Then nanoparticles are dispersed to obtain stable inks that could be directly used for thin-film deposition via spin coating.We also obtain x-ray diffraction(XRD) peak intensities and absorption spectra for CIS experimentally. Finally, absorption spectra for the CdS window layer in several deposition times are investigated experimentally. 相似文献
707.
Matin-Alsadat Mostaan Jamal Davoodi Hadi Alizadeh Mohsen Yarifard 《The European Physical Journal B - Condensed Matter and Complex Systems》2018,91(10):260
In this paper, we study the tensile behavior of cylindrical rutile TiO2 nanowires, employing molecular dynamics (MD) simulation technique. The third-generation charge optimized many-body (COMB3) has been used for interatomic potential modeling. The influence of temperature and nanowire diameter on Young’s modulus is investigated. Our simulations exhibit the anisotropic behavior of Young’s modulus as a function of diameter for different crystallographic orientations. Although our results are in good accord with the existing results in [1 0 0] direction, Young’s modulus adds up monotonically with increasing the cross-sectional diameter of nanowire in [0 0 1] direction. It is found that Young’s modulus of the nanowires are lower (higher) than the bulk value for [0 0 1] ([1 0 0]) direction. Furthermore, simulation results also indicate that Young’s modulus of rutile TiO2 nanowire increases as a function of temperature for a given diameter, unexpectedly. The obtained results may be useful in the field of nanotechnology for optimizing mechanical performance to gain specific applications. 相似文献
708.
Hongwei Ge Kui Zhang Huan Yu Ji Yue Long Yu Xinfeng Chen Tianxin Hou Khalid A. Alamry Hadi M. Marwani Suhua Wang 《Journal of fluorescence》2018,28(6):1405-1412
This paper reported a dual-mode probe for D-penicillamine on the basis of pH-mediated gold nanoparticles aggregation and fluorescence resonance energy transfer (FRET) from carbon dots. D-penicillamine is a zwitterionic compound and has different forms depending on specific pH ranges. The thiol group of D-penicillamine has high affinity towards the surface of gold nanoparticles and can replace other surface ligands. When pH values were close to its isoelectrical point (pH(I)), the D-penicillamine capped gold nanoparticles aggregated through hydrogen bonding or electrostatic interactions, resulting in the releasing of carbon dots from gold nanoparticles. The dual-mode probe consisted of fluorescent carbon dots and gold nanoparticles, and the fluorescence of carbon dots was quenched by the attached gold nanoparticles due to the FRET. Then, the fluorescence can be recovered in presence of D-penicillamine due to the gold nanoparticles aggregation in specific pH range. Under the optimum conditions, the probe has linear response for D-penicillamine in the 0.25–1.5 μM concentration range with a detection limit of 0.085 μM. This method provides a potential application in sensitive detection of D-penicillamine. 相似文献
709.
Wave propagation modeling as a vital tool in seismology can be done via several different numerical methods among them are finite-difference, finite-element, and spectral-element methods (FDM, FEM and SEM). Some advanced applications in seismic exploration benefit the frequency domain modeling. Regarding flexibility in complex geological models and dealing with the free surface boundary condition, we studied the frequency domain acoustic wave equation using FEM and SEM. The results demonstrated that the frequency domain FEM and SEM have a good accuracy and numerical efficiency with the second order interpolation polynomials. Furthermore, we developed the second order Clayton and Engquist absorbing boundary condition (CE-ABC2) and compared it with the perfectly matched layer (PML) for the frequency domain FEM and SEM. In spite of PML method, CE-ABC2 does not add any additional computational cost to the modeling except assembling boundary matrices. As a result, considering CE-ABC2 is more efficient than PML for the frequency domain acoustic wave propagation modeling especially when computational cost is high and high-level absorbing performance is unnecessary. 相似文献
710.
Ali Rostamnejadi Hadi Salamati Parviz Kameli Hossein Ahmadvand 《Journal of magnetism and magnetic materials》2009,321(19):3126-3131
Magnetic nanoparticles of La0.67Sr0.33MnO3 (LSMO) manganite were prepared by sol-gel method. Phase formation and crystal structure of the synthesized powder were examined by the X-ray diffraction (XRD) using the Rietveld analysis. The mean particle size was determined by the transmission electron microscopy (TEM). Infrared transmission spectroscopy revealed that stretching and bending modes are influenced by calcinations temperature. The temperature dependence of the ac magnetic susceptibility was measured at different frequencies and ac magnetic fields in the selected ranges of 40-1000 Hz and 80-800 A/m, respectively. The temperature dependence of ac susceptibility shows a characteristic maxima corresponding to the blocking temperature near room temperature. The frequency dependence of the blocking temperature is well described by the Vogel-Fulcher law. By fitting the experimental data with this law, the relaxation time τ0=1.7×10−12 s, characteristic temperature T0=262±3 K, anisotropy energy Ea/k=684±15 K and effective magnetic anisotropy constant keff=2.25×104 erg/cm3 have been obtained. dc Magnetization measurement versus magnetic field shows that some of LSMO nanoparticles are blocked at 293 K. The role of magnetic interparticle interactions on the magnetic behavior is also investigated. 相似文献