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61.
Saeid Zamiri Bernhard Reitinger Engelbert Portenkirchner Thomas Berer Enrique Font-Sanchis Peter Burgholzer Niyazi Serdar Sariciftci Siegfried Bauer Fernando Fernández-Lázaro 《Applied physics. B, Lasers and optics》2014,114(4):509-515
We present two laser ultrasonic receivers based on organic photorefractive polymer composites with 2-[4-bis(2-methoxyethyl)aminobenzylidene]malononitrile (AODCST) or 2-dicyanomethylen-3-cyano-5,5-dimethyl-4-(4′-dihexylaminophenyl)-2,5-dihydrofuran nonlinear optical chromophores. Experimental results show sensitivities of the ultrasonic receivers of ~9.5 × 10?8 nm (W/Hz)0.5 for both composites, and a faster response time (~60 ms) for the AODCST-based laser ultrasonic receiver. We show that such LUS detectors are highly suitable for contactless thickness measurements of aluminum, steel sheets and defect detection with an accuracy of 100 μm. 相似文献
62.
63.
Reza Azadbakht Hassan Keypour Hadi Amiri Rudbari Ali Hossein Mohammad Zaheri Saeid Menati 《Journal of luminescence》2012,132(8):1860-1866
Two new macrocyclic systems (L1, L2) containing two emissive naphthalene were synthesized and characterized. The macrocycles were studied by 1H NMR, 13C NMR, COSY, HMQC, DEPT, microanalysis and mass spectroscopy. The influence of metal cations Na+, Cr3+, Mn2+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, and Hg2+ on the spectroscopic properties of the macrocyclic systems in acetonitrile/DMF 9:1 (v/v) mixtures were investigated by means of absorption and emission spectrophotometry. The macrocycle L1 was found to be as an effective fluorescence sensor for Zn2+ ions. Zn2+ and Cd2+ ions show the most effects on the fluorescence intensity of L2. 相似文献
64.
Zohreh Hamnabard Zahra Khalkhali Shamsi Sadat Alavi Qazvini Saeid Baghshahi Amir Maghsoudipour 《Journal of luminescence》2012,132(5):1126-1132
Four glasses in ZnO–SiO2–B2O3 ternary system were prepared by the melt quenching method with the objective of optimizing sub-nanosecond emission over the UV region of zinc borosilicate glasses used in superfast scintillators. The effect of vanadium addition and heat treatment on phase formation, microstructure and photoluminescence properties of the glasses was characterized by means of DTA, XRD, SEM and fluorescence spectrophotometer. Vanadium contributed to the near-band-edge emission in two ways, by introducing donor levels in the energy band of ZnO particles and by facilitating the precipitation of ZnO and willemite crystals. Furthermore, nucleation of willemite and zinc oxide phases, which are both the origins of the intense emission bands in the UV region, was facilitated with increasing either the time or temperature of heat treatments. Photoluminescence spectra showed the elimination of the visible emission band which is favorable in scintillating glasses. 相似文献
65.
Mohammad Ali Ansari Saeid Alikhani Ezeddin Mohajerani Reza Massudi 《Optics Communications》2012,285(5):851-855
In this study, the diffusion of photons in turbid media, like biological tissue has been studied. Due to scattering and absorption of photons in such media, the study of photon propagation in biological tissue is complicated. The several numerical methods have been presented to simulate the behavior of diffused photons. Recently, Boundary Integral Method (BIM) has been offered to simulate photon migration inside biological tissues. This method has advantage, e.g. lower computational time in compared with other numerical methods. In this study, the accuracy and precision of BIM compares with another numerical method like Monte Carlo technique and finite difference method, and also the calculated results obtained by BIM and Monte Carlo method evaluate with measured results. Furthermore, the effects of scattering and absorption coefficient of tissue on the measured signal are studied. 相似文献
66.
Review of nanofluids for heat transfer applications 总被引:2,自引:0,他引:2
Saeid Vafaei 《中国颗粒学报》2009,7(2)
Research on nanofluids has progressed rapidly since its enhanced thermal conductivity was first repotted about a decade ago,though much controversy and inconsistency have been reported,and insufficient understanding of the formulation and mechanism of nanofluids further limits their applications.This work presents a critical review of research on heat transfer applications of nanofluids with the aim of identifying the limiting factors so as to push forward their further development. 相似文献
67.
廖世俊 《应用数学和力学(英文版)》2008,29(2):223-228
A new modification of false position method for solving nonlinear equations is presented by applying homotopy analysis method (HAM). Some numerical illustrations are given to show the efficiency of algorithm. 相似文献
68.
Vickers hardness and refractive index was determined for Ca–Si–O–N glasses with 14.6–58 e/o N and 19–42 e/o Ca. By applying slow cooling rates, transparent glasses were obtained for compositions near Ca9.94Si10O17.73N8.14, while the majority of the glasses were opaque due to small inclusions of elemental Si and/or Ca-silicide. Determined glass densities varied between 2.80 and 3.25 g/cm3. Hardness was found to vary from 7.3 to 10.1 GPa at a load of 500 g and, respectively increase and decrease linearly with N and Ca content. The refractive index was found to increase linearly with N content from 1.62 to 1.95 and showed no significant dependence on Ca content. 相似文献
69.
Mohammad Hossein Jandaghian Saeid Ahmadjo Seyed Mohammad Mahdi Mortzavi Mostafa Ahmadi 《应用有机金属化学》2020,34(4):e5496
The reactive co-polymer approach is one of the most promising techniques for the synthesis of functional polyolefins. Following this concept, 1-hexene and p-methylstyrene are co-polymerized in the presence of a generic Brookhart-type catalyst. The microstructures of the co-polymers imply the tendency of p-methylstyrene co-monomers to place at the end of the structural branches formed by the chain walking reaction. The molar masses of the co-polymers decrease, not only at higher levels of co-monomer but surprisingly by decreasing reaction temperature. A mechanism consisting of a highly stable η3 metal–benzyl intermediate, which is quantitatively approved by density functional theory calculations, can delicately justify all the aforementioned observations. A series of the produced co-polymers is selectively functionalized by maleic anhydride at the benzylic position of p-methylstyrene, under very mild reaction conditions. Such a reactive intermediate opens the path for the introduction of different types of functionalities in polyolefins. Namely, the grafted co-polymers were further functionalized by a triazole ring, which provides a transient supramolecular network through intermolecular hydrogen bonding. 相似文献
70.
Saeid Farhadi Mozhgan Afshari Mansoureh Maleki Zaynab Babazadeh 《Tetrahedron letters》2005,46(49):8483-8486
An efficient, selective and green procedure for the photocatalytic oxidation of primary and secondary benzylic alcohols to the corresponding aldehydes and ketones has been achieved using silica-encapsulated H3PW12O40 as a recyclable heterogeneous photocatalyst in acetonitrile under oxygen gas as the sole reoxidant of the catalyst. 相似文献