A new structural wave number method to measure the dynamic characteristic parameters of viscoelastic damping material

For the viscoelastic damping material to possess excellent dissipating performance, it is crucial to obtain the dynamic characteristic parameters (DCP) of viscoelastic damping material exactly and effectively, and then to make it as input data for numerical analysis and design in the control of structural vibration. For this sake a new measurement method is presented to acquire the DCP of the viscoelastic damping material effectively in the manuscript. The properties of damping material can be achieved by substituting tested wave numbers or loss factor of composite viscoelastic damping beam (CVDB) into its inversion process of complex bending stiffness. In the present study, the loss factor of beam with unconstrained viscoelastic damping layer is measured by McDaniel and attenuation methods, respectively. And those results are compared with each other to certify the accuracy of test results firstly. Then influences of test conditions on loss factors derived from McDaniel method are studied to give some advices in the measurement. Finally the DCP of the viscoelastic damping material are obtained by the new method with complex wave number and compared with those obtained by using the resonance beam method. From the comparison it is concluded that the present proposed new approach can use limited samples to measure the DCP of the viscoelastic damping material in a wide range of frequencies effectively and conveniently

Atomically precise AuxAg25−x nanoclusters with a modulated interstitial Au–Ag microenvironment for enhanced visible-light-driven photocatalytic hydrogen evolution

Herein, we report the study of atomically precise AuxAg25−x nanoclusters (NCs) toward photocatalytic hydrogen evolution. The incorporation of Au atoms into Ag25 NCs not only narrowed the HOMO–LUMO gaps but also created an interstitial Au–Ag microenvironment, which promoted the photogenerated charge carrier utilization and optimized the reaction dynamics.Peer Reviewe

An analytical approach to study the dynamic characteristic of beams carrying any type of attachments with arbitrary distributions under elastic constraint boundary supports

An analytical method to study the dynamic characteristic of free vibration of beams carrying any type of attachments with arbitrary distributions on elastic constraint boundary supports is developed in the paper. To obtain an exact solution of the governing function, the displacement function is expressed as a modified Fourier series based on the Euler-Bernoulli beam differential equation, which consists of a standard Fourier cosine series plus several supplementary series used to improve uniform convergence of the series representation. Compared with other techniques, the current method offers a unified solution to entire situations of beams carrying various types of attachments, regarding different distributions and arbitrary boundary conditions. The results of different numerical examples are compared with the results of the references to illustrate the excellent accuracy of the current solution and validate the methodology. Furthermore, the proposed analytical method can be directly extended to caculate the natural frequencies of beam on Pasternak soil and with distribution attachment varying with its length which is never studied before

7-Meth­oxy-3-(4-meth­oxy­phen­yl)chroman-4-one

The asymmetric unit of the title compound, C17H16O4, contains two crystallographically independent mol­ecules with different absolute configurations

Taenionema sinensis sp. n., the first endemic species of Taenionema Banks, 1905 (Plecoptera, Taeniopterygidae) from China

The taeniopterygid genus Taenionema Banks, 1905 currently contains 14 species distributed in the Nearctic and the eastern Palearctic Regions. Taenionema japonicum (Okamoto, 1922) is the only species known from the Eastern Hemisphere, specifically in Japan, Korea, Mongolia, Russia and north-eastern China. The authors recently described the larvae of an undetermined Taenionema species, which was supposed to represent a second Palaearctic species.This paper reports the first endemic species of Taenionema Banks, 1905, Taenionema sinensis sp. n. from China, which also represents the second species of Taenionema from the Eastern Hemisphere. Description and illustrations based on male and female adults are provided. The new species is easily distinguished from all congeners by the bilobed abdominal sternum 9 of the male adult. The female adult is characterised by the posteriorly truncate postgenital plate. The male larva is distinguished by the emarginate subgenital plate and hook-shaped paraprocts

The effect of transforming growth factor-β1 on nasopharyngeal carcinoma cells: insensitive to cell growth but functional to TGF-β/Smad pathway

<p>Abstract</p> <p>Objectives</p> <p>This study explored the response of nasopharyngeal carcinoma cells to TGF-β1-induced growth suppression and investigated the roles of the TGF-β/Smad signaling pathway in nasopharyngeal carcinoma cells.</p> <p>Methods</p> <p>The cells of nasopharyngeal carcinoma cell line CNE2 were treated with TGF-β1. The growth responses of CNE2 cells were analyzed by MTT assay. The mRNA expression and protein subcellular localization of the TGF-β/Smad signaling components in the CNE2 were determined by real time RT-PCR and immunocytochemical analysis.</p> <p>Results</p> <p>We found that the growth of CNE2 cells was not suppressed by TGF-β1. The signaling proteins TβRII, Smad 7 were expressed normally, while Smad2, Smad3, and Smad4 increased significantly at the mRNA level. TGF-β type II receptor and Smad7 had no change compared to the normal nasopharyngeal epithelial cells. In addition, Smad2 was phosphorylated to pSmad2, and the activated pSmad2 translocated into the nucleus from the cytoplasm, while the inhibitory Smad-Smad7 translocated from the nucleus to the cytoplasm after TGF-β1 stimulation.</p> <p>Conclusion</p> <p>The results suggested that CNE2 cells are not sensitive to growth suppression by TGF-β1, but the TGF-β/Smad signaling transduction is functional. Further work is needed to address a more detailed spectrum of the TGF-β/Smad signaling pathway in CNE2 cells.</p

Methyl 2-{[2,8-bis­(trifluoro­meth­yl)quinolin-4-yl]­oxy}acetate

In the crystal structure of the title compound, C14H9F6NO3, mol­ecules are connected by inter­molecular C—H⋯O hydrogen bonds. The best planes through the benzene and pyridyl rings make a dihedral angle of 1.59 (12)°