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101.
Least‐squares spectral method for velocity‐vorticity‐pressure form of the Stokes equations
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Byeong‐Chun Shin Peyman Hessari 《Numerical Methods for Partial Differential Equations》2016,32(2):661-680
The aim of this article is to present and analyze first‐order system least‐squares spectral method for the Stokes equations in two‐dimensional spaces. The Stokes equations are transformed into a first‐order system of equations by introducing vorticity as a new variable. The least‐squares functional is then defined by summing up the ‐ and ‐norms of the residual equations. The ‐norm in the least‐squares functional is replaced by suitable operator. Continuous and discrete homogeneous least‐squares functionals are shown to be equivalent to ‐norm of velocity and ‐norm of vorticity and pressure for spectral Galerkin and pseudospectral method. The spectral convergence of the proposed methods are given and the theory is validated by numerical experiment. Mass conservation is also briefly investigated. © 2015 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 32: 661–680, 2016 相似文献
102.
Vahid Parvaneh Farhan Golkarmanesh Nawab Hussain Peyman Salimi 《Journal of Fixed Point Theory and Applications》2016,18(4):905-925
Recently, Jleli and Samet [J. Inequal. Appl. (2014), 2014:38] introduced and studied a new contraction to prove a generalization of the Banach contraction principle. In this paper, we introduce the concept of \({\alpha}\)-\({H\Theta}\)-contraction with respect to a general family of functions H and we establish Jleli–Samet-type fixed point results in metric and ordered metric spaces. As an application of our results we deduce Suzuki-type fixed point results for \({H\Theta}\)-contractions. We also derive certain fixed and periodic point results for orbitally continuous generalized \({\Theta}\)-contractions. Moreover, we present an illustrative example to highlight the obtained improvements. 相似文献
103.
Fatemeh Keyvani Hanjia Zheng Dr. Md. R. Kaysir Dragos F. Mantaila Peyman Ghavami Nejad Fasih A. Rahman Dr. Joe Quadrilatero Dr. Dayan Ban Dr. Mahla Poudineh 《Angewandte Chemie (International ed. in English)》2023,62(21):e202301624
Point-of-care testing (POCT) of clinical biomarkers is critical to health monitoring and timely treatment, yet biosensing assays capable of detecting biomarkers without the need for costly external equipment and reagents are limited. Blood-based assays are, specifically, challenging as blood collection is invasive and follow-upprocessing is required. Here, we report a versatile assay that employs hydrogel microneedles (HMNs) to extract interstitial fluid (ISF), in a minimally invasive manner integrated with graphene oxide-nucleic acid (GO.NA)-based fluorescence biosensor to sense the biomarkers of interest in situ. The HMN-GO.NA assay is supplemented with a portable detector, enabling a complete POCT procedure. Our system could successfully measure four clinically important biomarkers (glucose, uric acid (UA), insulin, and serotonin) ex vivo, in addition, to accurately detecting glucose and UA in vivo. 相似文献
104.
A one-pot combination of a modified Friedländer annulation and a Knoevenagel condensation provides 2-styrylquinolines in good to excellent yields. A variety of substrates are reacted in one-pot in the presence of 1-methylimidazolium trifluoroacetate ([Hmim]TFA). 相似文献
105.
Imaging in Raman spectroscopy is a valuable tool for analytical chemistry. Although molecular characterization at micron level is achieved for many applications, it usually fails producing chemical images of micron size samples as expected in chemical, environmental and biological analysis. The aim of the work is to introduce the potential of super-resolution in vibrational spectroscopic imaging. This original chemometrics approach uses several low resolution images of the same sample in order to retrieve a higher resolution chemical image. It is thus possible to overcome in a certain way some physical and instrumentals limitations. To illustrate the methodology, sub-micronic details of a Si/Au sample are retrieved from low resolution images with different super-resolution algorithms. The better results are obtained with Iterative L2/Bilateral Total Variation regularization method. The use of a regularization procedure gives also better results since its first property is to preserve edges during the reconstruction of the super-resolved image. This concept of chemical image data processing should open new analytical opportunities. 相似文献
106.
Modified clay/polyethersulfone (PES) mixed matrix membranes (MMMs) were prepared by acid activated montmorillonite (AA-MMT) with different concentrations and used to eliminate dyes and remove heavy metals from aqueous solution.The morphology and physiochemical properties of prepared clay nanoparticles and MMMs were characterized using X-ray diffraction (XRD),Fourier transform infrared (FTIR) spectroscopy,scanning electron microscopy (SEM),enegy dispersive X-ray (EDX) spectroscopy,Brunauer-Emmett-Teller (BET) analysis,atomic force microscopy (AFM),contact angle measurement and fouling studies.The filtration study showed that removal of dyes and heavy metals was strongly dependent on pH so that dyes with positive and negative charges showed different separation efficiency in acidic and alkaline conditions.The modified membranes possessed better heavy metal removal in acidic and alkaline pHs.When the rejection of heavy metals was measured in an alkaline environment,it was observed that the rejection had a great increase compared to the neutral values for Zn2+ and Ni2+ ions,while rejection of Cu2+ and Cd2+ did not undergo significant changes.So it can be concluded that modified membranes show good selectivity for elimination of Zn2+ and Ni2+ ions with respect to other cations. 相似文献
107.
108.
In this ever-changing world, organizations need to outsource parts of their processes for having agile response to market’s
needs and varying demands. Because of temporal nature of virtual enterprises (VE’s), the situation of outsourcing process
in this kind of organizations is a vital situation. The main idea of this paper aims to present a decision-making framework
for specific area that is appropriated for complex states. Its contribution is developing a fuzzy VlseKriterijumska Optimizacija
I Kompromisno Resenje (VIKOR) method and combining it with fuzzy analytic hierarchy process (AHP). This extension suitable
for decision-making situations which is faced with mixture appraisement that simultaneously regarded to both “group utility”
or majority and “individual regret” of the opponent. The Integrated and developed model suits to inconsistent conditions that
we face to collection of criteria and subcriteria that should satisfy some of them collectively and simultaneously and in
other attainment of some individual criteria is desirable. This framework then extended to a case study with varied criteria
for outsourcing process. 相似文献
109.
Peyman Salehi Mohsen Irandoost Behnam Seddighi Farahnaz Kargar Behbahani Daryush Poor Tahmasebi 《合成通讯》2013,43(10):1743-1747
Alcoholysis of allylic, secondary and tertiary benzylic ethers is proceeded efficiently in the presence of catalytic amounts of ferric ion as anhydrous FeCl3 and Fe(ClO4)3. 相似文献
110.
Abdol R. Hajipour Peyman Hosseini Arnold E. Ruoho 《Phosphorus, sulfur, and silicon and the related elements》2013,188(10):2502-2508
A variety of carbonyl containing compounds have been successfully reacted with 1,2-ethanedithiol in a thioacetylization reaction using tetrabutylammonium hydrogensulfate as a mild and efficient catalyst. Aldehydes and ketones react with good to excellent yields under mild conditions. 相似文献