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81.
Molybdenum (Mo) supported on aluminum-pillared clay (Al-PILC) and zirconium-pillared clay (Zr-PILC) with contents of 0.6, 1.4 and 2.8 atoms of Mo/nm2 were prepared and tested in the hydrogenation (HYD) of naphthalene (NP). It was found that the molybdenum sulfide (MoS2) catalysts supported on Zr- pillared clays were more active than the samples supported on Al-pillared clays and catalysts supported on alumina. The catalysts were characterized by X-ray diffraction (XRD), thermogravimetric analysis, nitrogen adsorption and transmission electron microscopy (TEM). Characterization analysis clearly pointed out to a close interaction of MoS2 with ZrO2 in the pillared clays. Therefore, the highest hydrogenation activities can be related to the presence of an interaction of MoS2 with ZrO2, probably with a different electronic interaction between the active phase and the support, than that reported for the MoS2/Al2O3 system. 相似文献
82.
Juan C. Gutierrez Fernandez Claudia I. Garcia José Ignacio Martinez M. L. R. Montoya 《代数通讯》2013,41(10):4481-4497
Whether or not a finite-dimensional, commutative, power-associative nilalgebra is solvable is a well-known open problem. In this paper, we describe commutative, power-associative nilalgebras of dimension n ≥ 6 and nilindex n ? 1 based on the condition that n ? 4 ≤ dim 𝔄3 ≤ n ? 3. This paper is a continuation of [10], where we describe commutative power-associative nilalgebras of dimension and nilindex n. We observe that the Jordan case was obtained by L. Elgueta and A. Suazo in [2]. 相似文献
83.
Edwin De La Cruz‐Montoya Carlos Rinaldi 《Journal of Polymer Science.Polymer Physics》2011,49(16):1163-1172
The effect of nanoparticle surface chemistry on the thermal, mechanical, and magnetic properties of poly(methyl methacrylate) (PMMA) nanocomposites with cobalt ferrite nanofillers was studied by comparing nanofillers coated with oleic acid (OA; which does not covalently bond to the PMMA matrix) and 3‐methacryloxypropyltrimethoxysilane (MPS, which covalently bonds to the PMMA matrix). Thermogravimetric analysis revealed an increase in the thermal degradation temperature of the nanocomposites compared with the neat polymer. The effect of cobalt ferrite nanofiller on the glass transition temperature (Tg) of the nanocomposite was evaluated by differential scanning calorimetry. The Tg value of the material increased when the particles were introduced. Dynamic mechanical analysis indicated an increase in the storage modulus of the nanocomposite because of the presence of nanofiller and a shift in the peak of loss tangent toward higher temperature. Magnetic measurements indicated that both nanocomposites had a small hysteresis loop at 300 K and no hysteresis at 400 K. However, estimates of the nanofiller's rotational relaxation times and measurements of the zero field cooled temperature‐dependent magnetization indicate that the observed lack of hysteresis at 400 K is likely because of particle rotation in the polymer matrix. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011 相似文献
84.
Marius-F. Danca Miguel Romera Gerardo Pastor Fausto Montoya 《Nonlinear dynamics》2012,67(4):2317-2342
The review presents a parameter switching algorithm and his applications which allows numerical approximation of any attractor
of a class of continuous-time dynamical systems depending linearly on a real parameter. The considered classes of systems
are modeled by a general initial value problem which embeds dynamical systems continuous and discontinuous with respect to
the state variable, of integer, and fractional order. The numerous results, presented in several papers, are systematized
here on four representative known examples representing the four classes. The analytical proof of the algorithm convergence
for the systems belonging to the continuous class is presented briefly, while for the other categories of systems, the convergence
is numerically verified via computational tools. The utilized numerical tools necessary to apply the algorithm are contained
in Appendices A, B, C, D and E. 相似文献
85.
David J. Wiedenfeld Vladimir N. Nesterov Mark A. Minton Crystal L. Montoya 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(7):o536-o538
The title compounds, 1‐chloro‐3,6‐dimethoxy‐2,5‐dimethylbenzene, (IIIa), and 1‐chloro‐3,6‐dimethoxy‐2,4‐dimethylbenzene, (IIIb), both C10H13ClO2, were obtained from 2,5‐ and 2,6‐dimethyl‐1,4‐benzoquinone, respectively, and are intermediates in the synthesis of ammonium quinone derivatives. The isomers have different substituents around the methoxy groups and crystallize in different space groups. In both molecules, the methoxy groups each have different orientations with respect to the benzene ring. In both cases, one methoxy group lies in the plane of the ring and can participate in conjugation with the aromatic system, while the second is almost perpendicular to the plane of the aromatic ring. The C—O—C bond angles around these substituents are also different: 117.5 (4) and 118.2 (3)° in (IIIa) and (IIIb), respectively, when the methoxy groups lie in the plane of the ring, and 114.7 (3) and 113.6 (3)° in (IIIa) and (IIIb), respectively, when they are out of the plane of the ring. 相似文献
86.
Ligand‐Free Copper‐Catalyzed Negishi Coupling of Alkyl‐, Aryl‐, and Alkynylzinc Reagents with Heteroaryl Iodides
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Surendra Thapa Arjun Kafle Dr. Santosh K. Gurung Adam Montoya Patrick Riedel Prof. Ramesh Giri 《Angewandte Chemie (International ed. in English)》2015,54(28):8236-8240
Reported herein is an unprecedented ligand‐free copper‐catalyzed cross‐coupling of alkyl‐, aryl‐, and alkynylzinc reagents with heteroaryl iodides. The reaction proceeds at room temperature for the coupling of primary, secondary, and tertiary alkylzinc reagents with heteroaryl iodides without rearrangement. An elevated temperature (100 °C) is required for aryl–heteroaryl and alkynyl–heteroaryl couplings. 相似文献
87.
Vanessa Montoya Jordi García-Antón Mercè Font-Bardia 《Journal of fluorine chemistry》2007,128(9):1007-1011
The reaction of the β-diketone 4,4,4-trifluoro-1-pyridin-2-yl-butane-1,3-dione and the monosubstituted hydrazine 2-hydroxyethylhydrazine has been investigated. Two products have been identified, 2-(2-hydroxyethyl)-3-pyridin-2-yl-5-trifluoromethyl-4,5-dihydropyrazole (P) and 2-(3-pyridin-2-yl-5-trifluoromethylpyrazol-1-yl)ethanol (L) in proportion 2:8, when the reaction was done at room temperature in ethanol for 15 h. The preparation of P as a pure product was performed in ethanol at 0 °C for 7 h. P has been characterized by 1H, 13C{1H} and 19F{1H} NMR spectroscopy and by other techniques as appropriate. 相似文献
88.
Andreina Aguado John Boulos Anladys Carreras Angelica Montoya Judith Rodriquez 《Journal of heterocyclic chemistry》2007,44(6):1517-1520
89.
A system’s response to disturbances in an internal or external driving signal can be characterized as performing an implicit computation, where the dynamics of the system are a manifestation of its new state holding some memory about those disturbances. Identifying small disturbances in the response signal requires detailed information about the dynamics of the inputs, which can be challenging. This paper presents a new method called the Information Impulse Function (IIF) for detecting and time-localizing small disturbances in system response data. The novelty of IIF is its ability to measure relative information content without using Boltzmann’s equation by modeling signal transmission as a series of dissipative steps. Since a detailed expression of the informational structure in the signal is achieved with IIF, it is ideal for detecting disturbances in the response signal, i.e., the system dynamics. Those findings are based on numerical studies of the topological structure of the dynamics of a nonlinear system due to perturbated driving signals. The IIF is compared to both the Permutation entropy and Shannon entropy to demonstrate its entropy-like relationship with system state and its degree of sensitivity to perturbations in a driving signal. 相似文献
90.
Reichert D Montoya A Liang X Bockhorn H Haynes BS 《The journal of physical chemistry. A》2010,114(46):12323-12329
Molecular modeling is used to determine low-energy conformational structures and thermodynamic properties of levulinic acid in the gas phase. Structure and IR vibrational frequencies are obtained using density functional and M?ller-Plesset perturbation theories. Electronic energies are computed using G3//B3LYP and CBS-QB3 model chemistries. Computed anharmonic frequencies are consistent with reported experimental data. Population analysis shows a boat- and a chainlike structure to be most abundant at 298 K, with increasing proportions of two other conformers at higher temperatures. Population mean distribution values for thermodynamic quantities are derived. At 298 K and 1 atm, the enthalpy of formation, entropy, and heat capacity are -613.1 ± 1.0 kJ·mol(-1), 407.4 J·mol(-1)·K(-1), and 132.3 J·mol(-1)·K(-1), respectively. 相似文献