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61.
Turgeman R Tirosh S Gedanken A 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(7):1845-1850
We report herein on the oriented growth of ZnO crystals on magnetite nanoparticles. The ZnO crystals were grown by hydrolyzing a supersaturated aqueous solution of zinc nitrate. The seeds for the growth were magnetite nanoparticles with a diameter of 5.7 nm and a narrow size distribution. Hollowed ZnO hexagons of 0.15 microm width and 0.5 microm length filled with Fe(3)O(4) particles were obtained. HR-TEM (high-resolution transmission electron microscopy) and selected-area EDS (energy-dispersive spectroscopy) show that the nanoparticles are homogenously spread in the ZnO tubes. Zeta potential measurements were employed to understand the relationship between the nanoparticles and the oriented growth of the ZnO crystals. The results show that the surfactants induced the directional growth of the ZnO crystals. 相似文献
62.
The RAPET reaction at 700 degrees C, of different alkoxides (Ti, V, and Si) led to three different nanocomposites. Carbon is the element common to all three structures. Carbon was found as the core in the decomposition of TEOS, as the shell in the decomposition of VO(OEt)3 and embedded in, or mixed completely with, TiO2 in the decomposition of Ti(OiPr)4. This novel method using only metallic alkoxide precursor, in the absence of catalyst, leads in a one-step process to core-shell structures. 相似文献
63.
Aharon Atzmon 《Integral Equations and Operator Theory》1987,10(1):1-16
A method for estimating multiplicity of operators in terms of certain multilinear mappings is introduced. Several applications are given which include the following result: IfT is a completely non-unitary contraction on a complex Hilbert space, and
for some vectorx
0, then there exists a constant >0, such that for every positive integern, the multiplicity of the operatorT
n
is not less thann. This extends a result of B. Sz. Nagy and Foia [10]. 相似文献
64.
Gen-Tao Zhou Oleg Palchik R. Herber Aharon Gedanken 《Journal of solid state chemistry》2004,177(9):3014-3020
Two types of intermetallic lithium alloys, Li21Si5 and Li17Sn4 (previously Li22Si5 and Li22Sn5), were prepared for the first time using microwave-assisted solid-state reaction. The optimum oven power for their preparation is 80-60%, and the irradiation times are 5 min for Li21Si5 or 10 min for Li17Sn4. A cheap alumina crucible was found to be the most suitable container in quick (less than 10 min) microwave reactions for Li-containing alloys. The synthesized compounds were characterized by PXRD. Mössbauer spectroscopy was used to characterize Li17Sn4 under different conditions. The hyperfine interaction parameters of 119Sn in Li17Sn4 show a typical Li-Sn alloy Sn isomer shift (1.88 mm/s). The oxidization processes of the two intermetallic lithium alloys in air were investigated. The microwave method was found to be simple, fast and efficient, with high selectivity for the preparation of these compounds. 相似文献
65.
Aharon Gedanken 《Chemical physics letters》1984,110(6):626-629
The absorption and magnetic circular dichroism (MCD) of iodine in the gas phase was recorded over the wavelength range 1950-1780 Å. The strong MCD si 相似文献
66.
This paper presents an approximate affinely adjustable robust counterpart for conic quadratic constraints. The theory is applied
to obtain robust solutions to the problems of subway route design with implementation errors and a supply chain management
with uncertain demands. Comparison of the adjustable solutions with the nominal and non-adjustable robust solutions shows
that the adjustable (dynamic) robust solution maintains feasibility for all possible realizations, while being less conservative
than the usual (static) robust counterpart solution. 相似文献
67.
Cheryl Aharon Fernando G. Guijarro Samara Medina Rivero Prof. Francisco J. Ramírez Dr. Rubén Caballero Prof. Juan Casado Prof. Fernando Langa Prof. Shlomo Rozen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(2):464-468
Oligo-S,S-dioxothienylenevinylenes have been prepared by transferring oxygen atoms to the sulfur atoms using the HOF ⋅ CH3CN complex. Their photophysical properties are presented in comparison with their thiophenevinylene congeners. Together with their vibrational properties and molecular force fields, this study allows for the interpretation of the alteration of aromaticity and inter-ring exocyclic π-conjugation in this series. 相似文献
68.
Sagi Frishman Alexander Gumennik Har’el Ilan Aharon J. Agranat 《Applied physics. B, Lasers and optics》2014,115(1):143-147
Electro-optically tunable transmission grating was imprinted in potassium lithium tantalate niobate by irreversible spatial patterning of the dielectric constant. While embedded into waveguided architecture, it provides a reliable and versatile building block for opto-electronic circuitry, capable of both active switching and multiplexing. Realization of such a block is critical for the fabrication of integrated photonic circuits in electro-optic substrates by means of Refractive Index Engineering by fast ion implantation. 相似文献
69.
Titanium dioxide was synthesized by the hydrolysis of titanium tetraisopropoxide (TTIP) in the presence of acetic acid, 2-propanol, and organic amines (octylamine, aniline, and isobutylamine). H2O was supplied by an esterification reaction between acetic acid and 2-propanol (denoted as H2Oe), and/or by intentionally adding it (denoted as H2Oa). It was found that the quantity of H2Oa plays a crucial role in the morphology and porous structure of the final TiO2 product. Without the addition of H2Oa, 1D and porous TiO2 was synthesized. With the addition of H2Oa, and when the H2Oa:TiO2 molar ratio was in the range of 1:1 to 60:1, macroporous TiO2 microspheres possessing a large surface area and high thermal stability were obtained. When the H2Oa:TiO2 molar ratio exceeded 60:1, porous TiO2 with an irregular shape was formed. The variation in the morphology and porous structure is attributed to the manipulation of the growth kinetics by the addition of water. 相似文献
70.
Thermal decomposition of commercial silicone oil to produce high yield high surface area SiC nanorods 总被引:1,自引:0,他引:1
Pol VG Pol SV Gedanken A Lim SH Zhong Z Lin J 《The journal of physical chemistry. B》2006,110(23):11237-11240
This article reports on the synthesis of high surface area (563m2/g) beta-SiC nanorods by thermal decomposition of commercial silicone oil at a relatively low reaction temperature (800 degrees C) in a closed Swagelok cell. High yield (75%) of SiC nanorods are obtained in this one-stage, solvent-, catalyst-, and template-free synthesis technique that runs at a relative low temperature and employs cheap single-precursor. The morphological (TEM, HR-SEM), compositional (CHNS, EDX, SAEDX]), structural (XRD, HR-TEM, and ED), thermal (TGA) characterizations and surface area analysis are carried out for the obtained SiC nanorods. The possibility of hydrogen storage in this high surface area nano-SiC rods are also tested and reported for the first time. 相似文献