排序方式: 共有107条查询结果,搜索用时 500 毫秒
51.
Aragoni MC Arca M Demartin F Devillanova FA Isaia F Garau A Lippolis V Jalali F Papke U Shamsipur M Tei L Yari A Verani G 《Inorganic chemistry》2002,41(25):6623-6632
The macrocycles L(1)-L(3) incorporating N(2)S(3)-, N(2)S(2)O-, and N(2)S(2)-donor sets, respectively, and containing the 1,10-phenanthroline unit interact in acetonitrile solution with heavy metal ions such as Pb(II), Cd(II), and Hg(II) to give 1:1 ML, 1:2 ML(2), and 2:1 M(2)L complex species, which specifically modulate the photochemical properties of the ligands. The stoichiometry of the complex species formed during spectrofluorometric titrations and their formation constants in MeCN at 25 degrees C were determined from fluorescence vs M(II)/L molar ratio data. The complexes [Pb(L(1))][ClO(4)](2).(1)/(2)H(2)O (1), [Pb(L(2))][ClO(4)](2).MeNO(2) (1a), [Pb(L(3))(2)][ClO(4)](2).2MeCN (1b), and [Cd(L(3))][NO(3)](2) (2b) were also characterized by X-ray diffraction studies. The conformation adopted by L(1)-L(3) in these species reveals the aliphatic portion of the rings folded over the plane containing the heteroaromatic moiety with the ligands trying to encapsulate the metal center within their cavity. In 1, 1a, and 2b the metal ion completes the coordination sphere by interacting with counteranion units and solvent molecules. On the contrary, the 1:2 complex 1b shows Pb(II) sandwiched between two symmetry-related molecules of L(3) reaching an overall [4N + 4S] eight-coordination. 相似文献
52.
High‐Throughput Measurement of Binding Kinetics by mRNA Display and Next‐Generation Sequencing
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Dr. Farzad Jalali‐Yazdi Lan Huong Lai Prof. Terry T. Takahashi Prof. Richard W. Roberts 《Angewandte Chemie (International ed. in English)》2016,55(12):4007-4010
There is great demand for high‐throughput methods to characterize ligand affinity. By combining mRNA display with next‐generation sequencing, we determined the kinetic on‐ and off‐rates for over twenty thousand ligands without the need for synthesis or purification of individual members. Our results are reproducible and as accurate as those obtained with other methods of affinity measurement. 相似文献
53.
Blending of polymeric materials is an effective way to obtain materials with specific properties, since the properties of these multiphase polymeric materials are not only affected by the properties of the component polymers but also by the morphology formed. The research described here was focused on investigation of the morphology of polymer blends of poly lactic acid (PLA) and poly methyl methacrylate (PMMA) and the PLA/PMMA blends containing various amounts of graphene nano plates, (GNP). In this work, the blends were prepared by solution casting and the morphologies of these nano filled polymer blends were studied. By adding graphene nano plates into the PLA/PMMA blends, the morphology changed for all compositions. It was very interesting to note that the GNP were found to be preferentially located in one of the polymer phases, different for the different loadings, and its location determined the final morphology of the PLA/PMMA blends. The morphology of the blends was observed by SEM and the composition-morphology dependence responses were investigated using a Fourier transform infra-red (FTIR) spectroscopy technique. 相似文献
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55.
Amir Nejat Alireza Jalali Mahkame Sharbatdar 《ournal of non Newtonian Fluid Mechanics》2011,166(19-20):1158-1172
An implicit Newton–Krylov finite volume algorithm has been developed for efficient steady-state computation of the power-law non-Newtonian fluid flows. The pseudo-compressibility technique is used for the coupling of continuity and momentum equations. The spatial discretization is central (second-order) for both convective and diffusive terms and the accuracy of the solution is verified. The nine block diagonal Jacobian matrix (needed for implicit formulation) is computed directly through the flux differentiation. Five-diagonal and three-diagonal block matrices (the simplified versions of the main Jacobian matrix) are used with the ILU(0 & 1) and the Thomas linear solvers for preconditioning, respectively. The performance of the Newton-GMRES solver is examined in detail for different preconditioning strategies. The effects of the power-law behavior index and Re number on the convergence rate are also studied. The performance of the Newton-BiCGSTAB and the Newton-GMRES solvers are compared with each other. The results show, the ILU(1)/Newton-GMRES is the most efficient combination that is robust even in high Reynolds number shear-thinning fluid flow cases. 相似文献
56.
Seyed Javad Hosseininezhad Mohammad Saeed JabalameliSeyed Gholamreza Jalali Naini 《Applied Mathematical Modelling》2014
This paper presents a continuous capacitated location-allocation model with fixed cost as a risk management model. In the presented model, the fixed cost consists of production and installation costs. The model considers risk as percent of unsatisfied demands. The fixed cost is assigned to a zone with a predetermined radius from its center. Because of uncertain environment, demand in each zone is investigated as a fuzzy number. The model is solved by a fuzzy algorithm based on α-cut method. After solving the model based on different α-values, the zones with the largest possibilities are determined for locating new facilities and the best locations are calculated based on the obtained possibilities. Then, the model is solved based on different α-values to determine best allocation values. Also, this paper proposes a Cross Entropy (CE) algorithm considering multivariate normal and multinomial density functions for solving large scale instances and is compared with GAMS. Finally, a numerical example is expressed to illustrate the proposed model. 相似文献
57.
B. Jalali D.R. Solli K. Goda K. Tsia C. Ropers 《The European physical journal. Special topics》2010,185(1):145-157
Rogue events otherwise known as outliers and black swans are singular, rare, events that carry dramatic impact. They appear
in seemingly unconnected systems in the form of oceanic rogue waves, stock market crashes, evolution, and communication systems.
Attempts to understand the underlying dynamics of such complex systems that lead to spectacular and often cataclysmic outcomes
have been frustrated by the scarcity of events, resulting in insufficient statistical data, and by the inability to perform
experiments under controlled conditions. Extreme rare events also occur in ultrafast physical sciences where it is possible
to collect large data sets, even for rare events, in a short time period. The knowledge gained from observing rare events
in ultrafast systems may provide valuable insight into extreme value phenomena that occur over a much slower timescale and
that have a closer connection with human experience. One solution is a real-time ultrafast instrument that is capable of capturing
singular and randomly occurring non-repetitive events. The time stretch technology developed during the past 13 years is providing
a powerful tool box for reaching this goal. This paper reviews this technology and discusses its use in capturing rogue events
in electronic signals, spectroscopy, and imaging. We show an example in nonlinear optics where it was possible to capture
rare and random solitons whose unusual statistical distribution resemble those observed in financial markets. The ability
to observe the true spectrum of each event in real time has led to important insight in understanding the underlying process,
which in turn has made it possible to control soliton generation leading to improvement in the coherence of supercontinuum
light. We also show a new class of fast imagers which are being considered for early detection of cancer because of their
potential ability to detect rare diseased cells (so called rogue cells) in a large population of healthy cells. 相似文献
58.
Ricardo Claps Dimitrios Dimitropoulos Bahram Jalali Bernard Jusserand 《Superlattices and Microstructures》2006,39(6):501-516
This paper discusses the design of acoustic vibrational modes in Si/Ge planar optical waveguides and its application in creating silicon-based Raman devices with a flexible spectrum. It addresses the deficiencies of the recently demonstrated Raman-based silicon lasers and amplifiers as they relate to spectral and low efficiency limitations of bulk silicon. The treatment is for in-plane scattering in a forward scattering configuration. In addition to calculating the spectrum and the efficiency for Raman active modes, it is shown that the negligible wave-vector of the phonons involved in this type of scattering allows for the use of the bandgap “pinching” effect to arrive at specific layer thicknesses for Si and Ge that optimize the scattering efficiency. 相似文献
59.
A. D. Khalaji H. Mighani M. Gholinejad G. Grivani S. Jalali Akerdi K. Fejfarova M. Dusek 《Journal of Structural Chemistry》2013,54(4):766-773
In this study four coordinated complexes of zinc(II) halides with a new symmetrical bidentate Schiff base ligand (2,5-MeO-ba)2En are synthesized and characterized. The metal to ligand ratio of the complexes is found to be 1:1 with the formula of Zn((2,5-MeO-ba)2En)X2 (X = Cl (1), Br (2), I (3)). The crystal structure of the Schiff base ligand (2,5-MeO-ba)2En is determined by X-ray crystallography from single crystal data. Also, the optimized geometries of the Schiff base ligand (2,5-MeO-ba)2En and its zinc(II) complexes are calculated using the density functional theory method (B3LYP/6-31G). The obtained structural parameters of (2,5-MeO-ba)2En are in agreement with the experimental data. 相似文献
60.
Rapid granular shear flow is a classical example in granular materials which exhibits fluid-like behavior solely or fluid-like and solid-like behaviors simultaneously. We have performed experiments on annular granular shear flows using monodisperse steel spheres with 2-mm and 3-mm diameters. We discuss some transient (static failure of material due to shear) and steady-state (completely sheared and partially sheared flows) features of rapid granular flows. Our results map out the boundary between overall compaction and dilation that characterizes multiphase behavior of the system. Dimensionless stresses rise as more material is loaded into the system. On the other hand, increasing the compressive force or shear rate is equal to easing the process of shearing by decreasing the ratio of shear to normal stress. 相似文献