Physics of the Solid State - Molecular dynamics simulation was employed in this study to investigate the atomistic mechanisms involved in the Ni–Al alloy homogeneous deformation and the... 相似文献
A stable nickel‐decorated SBA‐15 nanocomposite (Ni/TCH@SBA‐15) was synthesized through surface modification of silica nanoparticles with 3‐chloropropyltriethoxysilane (CPTES) and thiocarbohydrazide (TCH) followed by metal–ligand coordination with Ni (II). The structure of this organometallic nanocomposite was characterized by Fourier transform‐infrared, field emission‐scanning electron microscopy, EDAX, transmission electron microscopy, atomic absorption spectroscopy and N2 adsorption–desorption (Brunauer–Emmett–Teller) techniques. The catalytic performance of Ni/TCH@SBA‐15 (NNTS‐15) was determined for the synthesis of 2‐aryl‐substituted benzimidazoles and 2,3‐dihydroperimidines. The excellent yields within shorter reaction times, simplicity of catalytic methods, non‐toxicity and clean reactions, mild reaction conditions and easy work‐up procedure are the important merits of these synthetic protocols. Moreover, the Ni (II) bonded to the SBA‐15 surface was stable under the catalytic reaction conditions resulting in its efficient recycling and reuse. 相似文献
Finite Element Method based on Rayleigh–Ritz energy formulation is applied to obtain the elastic behavior of functionally
graded thick truncated cone. The cone has finite length, and it is subjected to axisymmetric hydrostatic internal pressure.
The inner surface of the cone is pure ceramic and the outer surface is pure metal, and the material composition varying continuously
along its thickness. Using this method, the effects of semi-vertex angle of the cone and the power law exponent on distribution
of different types of displacements and stresses are considered. 相似文献
Principal component analysis (PCA) is a popular dimension-reduction method to reduce the complexity and obtain the informative aspects of high-dimensional datasets. When the data distribution is skewed, data transformation is commonly used prior to applying PCA. Such transformation is usually obtained from previous studies, prior knowledge, or trial-and-error. In this work, we develop a model-based method that integrates data transformation in PCA and finds an appropriate data transformation using the maximum profile likelihood. Extensions of the method to handle functional data and missing values are also developed. Several numerical algorithms are provided for efficient computation. The proposed method is illustrated using simulated and real-world data examples. Supplementary materials for this article are available online. 相似文献
The viscosity coefficients for the gaseous states of N2 and O2 and their mixtures are determined at zero and moderately density regimes. The Lennard‐Jones 12–6 (LJ 12–6) potential energy function is used as the initial model potential required y the technique. The interaction potential energies from the inversion procedure reproduce the viscosity commensurate to the best measurements. The initial density dependence of gaseous viscosity coefficient according to the Rainwater‐Friend theory, which was given by Najafi et al., has been considered for pure N2 and pure O2. 相似文献
Quantum chemical calculations using gradient-corrected DFT at the BP86/TZ2P+ level were carried out for the metal-dioxime complexes [M{RC(NOH)C(NO)R}2]with M = Ni, Pd, Pt, R = CH3, H, F, Cl, Br, Ph, CF3. The nature of the metal-ligand bond was investigated with an energy decomposition analysis (EDA). The complexes with electron donating substituents R = H, CH3 have the strongest metal-ligand interaction energies ΔEint, as well as the largest bond dissociation energies. The analysis of the bonding situation revealed that the metal ← ligand σ donation is much stronger than the metal → ligand π backdonation. The breakdown of the orbital interactions into the contributions of orbitals with different symmetry indicates that the donation from the in-plane lone-pair donor-orbitals of nitrogen into the dxy AO of the metal provides about one half of the stabilization which comes from ΔEorb. Inspection of the EDA data indicates that the electrostatic term ΔEelstat is more important for the trend of the metal-oxime interactions in [M{RC(NOH)C(NO)R}2] than the orbital term ΔEorb. 相似文献
The main aim of this research was to study the electrochemical behavior of novel optically active poly(amide-imide)s (PAIs). Polycondensation reactions of a 3,5-diamino-N-(4-hydroxyphenyl)benzamide with different synthetic diacid chlorides derivatives based on natural amino acids resulted in preparation of five different aromatic–aliphatic PAIs. These polymers were characterized by Fourier transform infrared, proton nuclear magnetic resonance, and elemental analyses. Also, we used electrochemical impedance spectroscopy for the evaluation of these novel optically active PAIs for the first time. Presence of p-substituted phenol groups in the structure of these polymers has been used for electrochemical investigation. Results showed that the oxidation currents in five diverse polymers were affected by their structures. In addition, the influence of carbon nanotubes on the oxidation of phenolic groups was studied using carbon paste matrix in an aqueous buffer solution (pH 7.0).
This paper addresses a method for predicting the participating constants in equation of state (EOS) for compressed polymeric
fluids using two scaling constants, the surface tension γg and the molar density ρg, both at the glass transition point. The theoretical EOS undertaken is the one attributed to Tao and Mason. The second virial
coefficients are calculated from a two-parameter corresponding states correlation, which is constructed with two constants
as scaling parameters, i.e., the surface tension γg and the molar density ρg. This new correlation has been applied to the Tao–Mason (TM) EOS to predict the volumetric behavior of several polymer melts.
The operating temperature range is from 291.25 to 603.4 K and pressures of up to 202.5 MPa. A collection of 516 data points
has been examined for the aforementioned polymers. The average absolute deviation between the calculated densities and the
experimental ones is of the order of 0.44%. 相似文献
In this paper, a simple method for detection of multiple edge cracks in Euler–Bernoulli beams having two different types of cracks is presented based on energy equations. Each crack is modeled as a massless rotational spring using Linear Elastic Fracture Mechanics (LEFM) theory, and a relationship among natural frequencies, crack locations and stiffness of equivalent springs is demonstrated. In the procedure, for detection of m cracks in a beam, 3m equations and natural frequencies of healthy and cracked beam in two different directions are needed as input to the algorithm. 相似文献