An Exact Series Solution for the Vibration of Mindlin Rectangular Plates with Elastically Restrained Edges

An analysis method is proposed for the vibration analysis of the Mindlin rectangular plates with general elastically restrained edges, in which the vibration displacements and the cross-sectional rotations of the mid-plane are expressed as the linear combination of a double Fourier cosine series and four one-dimensional Fourier series. The use of these supplementary functions is to solve the possible discontinuities with first derivatives at each edge. So this method can be applied to get the exact solution for vibration of plates with general elastic boundary conditions. The matrix eigenvalue equation which is equivalent to governing differential equations of the plate can be derived through using the boundary conditions and the governing equations based on Mindlin plate theory. The natural frequencies can be got through solving the matrix equation. Finally the numerical results are presented to validate the accuracy of the method

Stability Analysis for Stochastic Markovian Jump Reaction-Diffusion Neural Networks with Partially Known Transition Probabilities and Mixed Time Delays

The stability problem is proposed for a new class of stochastic Markovian jump reaction-diffusion neural networks with partial information on transition probability and mixed time delays. The new stability conditions are established in terms of linear matrix inequalities (LMIs). To reduce the conservatism of the stability conditions, an improved Lyapunov-Krasovskii functional and free-connection weighting matrices are introduced. The obtained results are dependent on delays and the measure of the space AND, therefore, have less conservativeness than delay-independent and space-independent ones. An example is given to show the effectiveness of the obtained results

Prototype study of 0.1% X00.1\%\,X_0 and MHz/cm2\mathrm{MHz/cm^2} tolerant Resistive Plate Chamber with Diamond-Like Carbon electrodes

A novel Resistive Plate Chamber (RPC) was designed with Diamond-Like Carbon (DLC) electrodes and performance studies were carried out for 384$\,\mathrm{\mu m}$ gap configuration with a $2\,\mathrm{cm}\times2\,\mathrm{cm}$ prototype. The use of thin films coated with DLC enables an ultra-low mass design of $< 0.1\%\,X_0$ with up to a four-layer configuration. At the same time, 42% MIP efficiency, and 180 ps timing resolution per layer were achieved in a measurement performed under a $1\,\mathrm{MHz/cm^2}$ non-MIP charged particle beam. In addition, we propose a further improved design for a $20\,\mathrm{cm}$-scale detector that can achieve 90% four-layer efficiency in an even higher $4\,\mathrm{MHz/cm^2}$ beam. In this paper, we describe the detector design, present the results of performance measurements, and characterize the rate capability of the DLC-based RPCs with a performance projection for an improved design.Comment: 8 page

Tree-ring stable carbon isotope-based April-June relative humidity reconstruction since AD 1648 in Mt. Tianmu, China

Based on accurate dating, we have determined the stable carbon isotope ratios (delta C-13) of five Cryptomeria fortunei specimens from Mt. Tianmu, a subtropical area in southern China. The five delta C-13 time series records are combined into a single representative delta C-13 time series using a &quot;numerical mix method.&quot; These are normalized to remove temporal variations of delta(13) C in atmospheric CO2 to obtain a carbon isotopic discrimination (Delta C-13) time series, in which we observe a distinct correlation between Delta C-13 and local April to June mean relative humidity (RH (AMJ) ) (n = 64, r = 0.858, p &lt; 0.0001). We use this relationship to reconstruct RH (AMJ) variations from ad 1648 to 2014 at Mt. Tianmu. The reconstructed sequence show that over the past 367 years, Mt. Tianmu area was relatively wet, but in the latter part of the twentieth century, under the influence of increasing global warming, it has experienced a sharp reduction in relative humidity. Spatial correlation analysis reveals a significant negative correlation between RH (AMJ) at Mt. Tianmu and Sea Surface Temperature (SSTs) in the western equatorial Pacific and Indian Ocean. In other words, there is a positive correlation between tree-ring delta C-13 in Mt. Tianmu and SSTs. Both observed and reconstructed RH (AMJ) show significant positive correlations with East Asian and South Asian monsoons from 1951 to 2014, which indicate that RH (AMJ) from Mt. Tianmu reflects the variability of the Asian summer monsoon intensity to a great extent. The summer monsoon has weakened since 1960. However, an increase in relative humidity since 2003 implies a recent enhancement in the summer monsoon

Experimental Realization of Weyl Exceptional Rings in a Synthetic Three-Dimensional Non-Hermitian Phononic Crystal

Weyl points (WPs) are isolated degeneracies carrying quantized topological charges, and are therefore robust against Hermitian perturbations. WPs are predicted to spread to the Weyl exceptional rings (WERs) in the presence of non-Hermiticity. Here, we use a one-dimensional (1D) Aubry-Andre-Harper (AAH) model to construct a Weyl semimetal in a 3D parameter space comprised of one reciprocal dimension and two synthetic dimensions. The inclusion of non-Hermiticity in the form of gain and loss produces a WER. The topology of the WER is characterized by both its topological charge and non-Hermitian winding numbers. The WER is experimentally observed in a 1D phononic crystal with the non-Hermiticity introduced by active acoustic components. In addition, Fermi arcs are observed to survive the presence of non-Hermitian effect. We envision our findings to pave the way for studying the high-dimensional non-Hermitian topological physics in acoustics.Comment: 14 pages, 5 figure