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411.
All real bodies are inhomogeneous, though in many such bodies the inhomogeneity is “mild” in that the response of the bodies can be “approximated” well by the response of a homogeneous approximation. In this study we explore the status of such approximations when one is concerned with bodies whose response is nonlinear. We find that significant departures in response can occur between that of a “mildly” inhomogeneous body and its homogeneous approximation (if the approximate model is restricted to a certain class), both quantitatively and qualitatively. We illustrate this fact within the context of a specific boundary value problem, the inflation of an inhomogeneous spherical shell. We also discuss the inappropriateness of homogenization procedures that lead to a homogenized stored energy for the body when in fact what is required is a homogenized model that predicts the appropriate stresses as they invariably determine the failure or integrity of the body. 相似文献
412.
Summary The rectilinear flow of a second-order fluid is considered between two infinitely wide and long parallel plates. The bottom plate is at rest and has a longitudinal slot in the direction of the flow, while the top plate moves in the flow direction with a constant speed. Upper and lower bounds for the pressure error are obtained by the use of the maximum principle applied to harmonic functions.
With 6 figures 相似文献
Zusammenfassung Es wird die geradlinige Strömung einer Flüssigkeit zweiter Ordnung zwischen zwei unendlich ausgedehnten parallelen Platten untersucht. Die mit einer rechteckigen, in Strömungsrichtung orientierten Nute versehene Grundplatte befindet sich in Ruhe, wohingegen die glatte Deckplatte sich mit konstanter Geschwindigkeit in Strömungsrichtung bewegt. Untere und obere Schranken für die Abweichung des Druckes infolge der Nute (pressure error) werden durch Anwendung des Maximumprinzips auf harmonische Funktionen berechnet.
With 6 figures 相似文献
413.
This paper introduces a damage diagnosis algorithm for civil structures that uses a sequential change point detection method. The general change point detection method uses the known pre- and post-damage feature distributions to perform a sequential hypothesis test. In practice, however, the post-damage distribution is unlikely to be known a priori, unless we are looking for a known specific type of damage. Therefore, we introduce an additional algorithm that estimates and updates this distribution as data are collected using the maximum likelihood and the Bayesian methods. We also applied an approximate method to reduce the computation load and memory requirement associated with the estimation. The algorithm is validated using a set of experimental data collected from a four-story steel special moment-resisting frame and multiple sets of simulated data. Various features of different dimensions have been explored, and the algorithm was able to identify damage, particularly when it uses multidimensional damage sensitive features and lower false alarm rates, with a known post-damage feature distribution. For unknown feature distribution cases, the post-damage distribution was consistently estimated and the detection delays were only a few time steps longer than the delays from the general method that assumes we know the post-damage feature distribution. We confirmed that the Bayesian method is particularly efficient in declaring damage with minimal memory requirement, but the maximum likelihood method provides an insightful heuristic approach. 相似文献
414.
Daniel Costabel Artem Skabeev Afshin Nabiyan Dr. Yusen Luo Johannes B. Max Dr. Ashwene Rajagopal Daniel Kowalczyk Prof. Dr. Benjamin Dietzek Dr. Maria Wächtler Dr. Helmar Görls Prof. Dr. Dirk Ziegenbalg Assoc. Prof. Dr. Yulian Zagranyarski Prof. Dr. Carsten Streb Prof. Dr. Felix H. Schacher Prof. Dr. Kalina Peneva 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(12):4081-4088
In this work, we present a new synthetic strategy for fourfold-substituted perylene monoimides via tetrabrominated perylene monoanhydrides. X-ray diffraction analysis unveiled the intramolecular stacking orientation between the substituents and semicircular packing behavior. We observed the remarkable influence of the substituent on the longevity and nature of the excited state upon visible light excitation. In the presence of poly(dehydroalanine)-graft-poly(ethylene glycol) graft copolymers as solubilizing template, the chromophores are capable of sensitizing [Mo3S13]2− clusters in aqueous solution for stable visible light driven hydrogen evolution over three days. 相似文献
415.
S. Vijay Kumar G. Rudresha Sandip Gurav Mohd Zainuddin Purushottam Dewang Raghava Reddy Kethiri Sriram Rajagopal Ramesh Mullangi 《Biomedical chromatography : BMC》2013,27(2):203-207
A novel, simple, specific, sensitive and reproducible high‐performance liquid chromatography (HPLC) assay method has been developed and validated for the estimation of abiraterone (ART) in rat plasma. The analytical procedure involves extraction of ART and diclofenac (internal standard, IS) from rat plasma with a simple liquid–liquid extraction process. The chromatographic analysis was performed on a Waters Alliance system with a Betasil C18 column maintained at ambient room temperature and an isocratic mobile phase [acetonitrile–water–10 mm potassium dihydrogen phosphate (pH 3.0), 55:5:40, v/v/v] at a flow rate of 1.00 mL/min with a total run time of 10 min. The eluate was monitored using an UV detector set at 255 nm. Method validation was performed as per FDA guidelines and the results met the acceptance criteria. The calibration curve was linear over a concentration range of 93.4–3251 ng/mL (r2 = 0.997). The intra‐ and inter‐day precisions were 0.56–4.98 and 3.03–7.18, respectively, in rat plasma. The validated HPLC method was successfully applied to a pharmacokinetic study of ART in rats. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
416.
The electron transfer (ET) reaction of aryl methyl sulfoxides with ruthenium(III)-polypyridine complexes is sensitive to the change of substituent in the aryl moiety of ArS(O)CH3 and ligand of Ru(III) complex. The detection of sulfoxide radical cation as the transient by conventional flash photolysis confirms ET in the rate-controlling step. The successful application of Marcus cross relation of ET leads to the evaluation of self-exchange rate constant of ArS+(O)CH3/ArS(O)CH3 as 4.0×105 M−1 s−1 similar to organic sulfides. Comparison with the reactivity of iron(III)-polypyridyl complexes points out that both reactivity and ρ values are higher with Ru(III) complexes. 相似文献
417.
[reaction: see text] The first synthesis of dendralene-type TTF derivatives bearing a 1,3-ditellurole ring has been achieved. Preliminary electrochemical results are presented. 相似文献
418.
Thanasekaran P Liao RT Manimaran B Liu YH Chou PT Rajagopal S Lu KL 《The journal of physical chemistry. A》2006,110(37):10683-10689
Electron-transfer (ET) reactions from aromatic amines to excited states of rhenium(I)-based molecular rectangles [{Re(CO)3(mu-bpy)Br}{Re(CO)3(mu-L)Br}]2 (bpy = 4,4'-bipyridine, L = 4,4'-dipyridylacetylene (dpa), I; L = 4,4'-dipyridylbutadiyne (dpb), II; and L = 1,4-bis(4'-pyridylethynyl)benzene (bpeb), III) were investigated in a dichloromethane solution using luminescence quenching techniques. Direct evidence for the ET reaction was obtained from the detection of the amine cation radical in this system using time-resolved transient absorption spectroscopy. The values of the luminescence quenching rate constants, kq, of the 3MLCT excited state of Re(I) rectangles with amines were found to be higher than those for the monomeric Re(I) complexes and other Re(I)-based metallacyclophanes. The observed kq values were correlated well with the driving force (Delta G degrees) for the ET reactions. In addition, a semiclassical theory of ET was successfully applied to the photoluminescence quenching of Re(I) rectangles with amines. 相似文献
419.
Monometallic and bimetallic diimine complexes of rhenium(I) and osmium(II), [(CO)3(bpy)Re(4,4′-bpy)](PF6) I, [(CO)3(bpy)Re(4,4′-bpy)Re(bpy)(CO)3](PF6)2II, [Cl(bpy)2Os(4,4′-bpy)](PF6) III and [Cl(bpy)2Os(4,4′-bpy)Os(bpy)2Cl](PF6)2IV, and a new heterobimetallic complex of rhenium(I) and osmium(II) [(CO)3(bpy)Re(4,4′-bpy)Os(bpy)Cl](PF6)2V (bpy = 2,2′-bipyridine; 4,4′-bpy = 4,4′-bipyridine) have been synthesized and characterized by various spectral techniques. The photophysical properties of all the complexes have been studied and a comparison is made between the heterobimetallic and corresponding monometallic and homobimetallic complexes. Emission and transient absorption spectral studies reveal that excited state energy transfer from the rhenium(I) chromophore (∗Re) to osmium(II) takes place. The energy transfer rate constant is found to be 8.7 × 107 s−1. 相似文献
420.
Kuldeep Sharma Gopal Pawar Swetha Yadam Sanjeev Giri Sriram Rajagopal Ramesh Mullangi 《Biomedical chromatography : BMC》2013,27(3):356-364
A highly sensitive and specific LC‐MS/MS‐ESI method has been developed for simultaneous quantification of metformin (MFN) and repaglinide (RGN) in rat plasma (50 μL) using phenacetin as an internal standard (IS). Simple protein precipitation was used to extract MFN and RGN from rat plasma. The chromatographic resolution of MFN, RGN and IS was achieved with a mobile phase consisting of 0.2% formic acid in water–acetonitrile (1:1, v/v) with a time program flow gradient on a Chromolith RP‐18e column. The total chromatographic run time was 3.5 min and the elution of MFN, RGN and IS occurred at 1.64, 2.21 and 2.15 min, respectively. A linear response function was established for the range of concentrations 0.855–394 and 0.021–21.7 ng/mL for MFN and RGN, respectively. The intra‐ and inter‐day precision values for MFN and RGN met the acceptance as per FDA guidelines. MFN and RGN were stable in battery of stability studies viz., bench‐top, auto‐sampler and freeze–thaw cycles. The developed assay was applied to a pharmacokinetic study in rats. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献