Acoustic emission (AE) signals produced by different types of rocks have different characteristics of information. Determining the brittle mineral content of rock according to the acoustic emission ...characteristics of rock is helpful to understand the mechanical behavior of rock in field monitoring. This article constructs a deep learning algorithm model to identify acoustic emission signals released from rock fractures with different brittle mineral contents. In response to the interference characteristics of acoustic emission signal data, a multiscale one-dimensional convolutional neural network embedded with efficient channel attention (ECA) module was incorporated into the model, and multiscale convolutional kernels were used to extract features of different levels of precision. In the latter half of the model, the BLSTM network was incorporated to extract time series-related features, local spatial uncorrelated features, and weak periodic pattern features from the acoustic emission signal data. To solve the problem that the recognition accuracy of minority samples decreases, this study replaces ReLU activation function with SELU. The results show that the multiscale 1DCNN-BLSTM model embedded in ECA module has a good antinoise performance, and the recognition accuracy can reach over 90%. The discovery of this work provides a new idea for exploring the mechanism of rock mass instability.
Abstract
Inorganic glass is a non-crystalline material that lacks of a regular, periodic atomic or molecular structure, and are considered as frozen liquids because of the similarity between their ...static amorphous structures. The atoms and molecules in the glass can gradually rearrange and realign with time, giving rise to deformation or aging in most glass materials. However, viscoelastic behavior could not be readily observable at room temperature (RT) due to its long time scale. The paper introduce and comment a recent work published in Nature Energy, which discover a new class of viscoelastic inorganic glass with Tg well below RT. The VIGLAS is simply synthesized through adding high content of oxygen into tetrachloroaluminates to replace chlorine. The VIGLAS exhibits characteristics similar to both inorganic ceramics and organic polymers, which are particularly relevant in the realm of battery electrolytes where a balance between ionic conductivity and chemo-mechanical compatibility is crucial.
This paper is concerned with the existence and multiplicity to $p$-biharmonic equation with Sobolev–Hardy term under Dirichlet boundary conditions and Navier boundary conditions, respectively. We ...focus on the case of the nonlinear terms without the Ambrosetti–Rabinowitz conditions. Our method is based on the variational method.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Tellurium (Te) films with monolayer and few-layer thickness are obtained by molecular beam epitaxy on a graphene/6H-SiC(0001) substrate and investigated by in situ scanning tunneling microscopy and ...spectroscopy (STM/STS). We reveal that the Te films are composed of parallel-arranged helical Te chains flat-lying on the graphene surface, exposing the (1 × 1) facet of (101̅0) of the bulk crystal. The band gap of Te films increases monotonically with decreasing thickness, reaching the near-infrared band for the monolayer Te. An explicit band bending at the edge between the monolayer Te and graphene substrate is visualized. With the thickness controlled in the atomic scale, Te films show potential applications of electronics and optoelectronics.
A simple semiclassical drude-like conductivity of graphene is employed to describe plasmon excitations of graphene in the ring structures. A quasi-static self-consistent integral equation approach is ...performed, allowing the calculation of all the plasmon modes with different angular momentum l. Among them only the dipole modes (l = 1) will couple out to the radiation modes, which in turn can be excited optically by the plane waves, and the excitation energies as a function of the ratio of the radius of the inner hole to that of the outer ring have also been investigated. It is demonstrated that the energy of symmetric modes will monotonically decrease as the ratio rises, and the energy of antisymmetric modes does not exhibit a monotonically increasing behavior as in a three-dimensional metallic ring, but first reduces and then increases. These predictions are tested by full-wave simulations using the optical conductivity of graphene that was obtained from the random phase approximation (RPA).
Cohort studies in North America and western Europe have reported increased risk of mortality associated with long-term exposure to fine particles (PM
), but to date, no such studies have been ...reported in China, where higher levels of exposure are experienced.
We estimated the association between long-term exposure to PM
with nonaccidental and cause-specific mortality in a cohort of Chinese men.
We conducted a prospective cohort study of 189,793 men 40 y old or older during 1990-91 from 45 areas in China. Annual average PM
levels for the years 1990, 1995, 2000, and 2005 were estimated for each cohort location using a combination of satellite-based estimates, chemical transport model simulations, and ground-level measurements developed for the Global Burden of Disease (GBD) 2013 study. A Cox proportional hazards regression model was used to estimate hazard ratios (HR) for nonaccidental cardiovascular disease (CVD), chronic obstructive pulmonary disease (COPD), and lung-cancer mortality. We also assessed the shape of the concentration-response relationship and compared the risk estimates with those predicted by Integrated Exposure-Response (IER) function, which incorporated estimates of mortality risk from previous cohort studies in western Europe and North America.
The mean level of PM
exposure during 2000-2005 was 43.7 μg/m
(ranging from 4.2 to 83.8 μg/m
). Mortality HRs (95% CI) per 10-μg/m
increase in PM
were 1.09 (1.08, 1.09) for nonaccidental causes; 1.09 (1.08, 1.10) for CVD, 1.12 (1.10, 1.13) for COPD; and 1.12 (1.07, 1.14) for lung cancer. The HR estimate from our cohort was consistently higher than IER predictions.
Long-term exposure to PM
was associated with nonaccidental, CVD, lung cancer, and COPD mortality in China. The IER estimator may underestimate the excess relative risk of cause-specific mortality due to long-term exposure to PM
over the exposure range experienced in China and other low- and middle-income countries. https://doi.org/10.1289/EHP1673.
Celotno besedilo
Dostopno za:
CEKLJ, DOBA, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
The photothermal biosensing principle is of increasing interest for point-of-care detection, but has rarely been applied in portable analytical devices in a lab-on-a-chip format. Herein, a ...photothermally responsive poly (methyl methacrylate) (PMMA)/paper hybrid disk (PT-Disk) was developed as a novel photothermal immunoassay device with the integration of a clip-magazine-assembled photothermal biosensing strategy. The PT-Disk consisted of a dissociative thermoresponsive hydrogel-loaded clip unit where the sandwich-type immunoreaction with an iron oxide-to-Prussian blue nanoparticle (PB NP) conversion took place and a magazine bearer for the rotational clip assembly and visual signal outputs. Upon laser irradiation of the clip-magazine-assembled PT-Disk, on-chip photothermal effect of PB NPs triggered both dose-dependent temperature elevation and the subsequent release of dye solutions from the central clip unit to surrounding magazine-bearing paper channels as the result of phase transition of the hydrogels, realizing multiplexed thermal image- and distance-based visual quantitative signal outputs in combination with the preliminary colorimetric readout on the PT-Disk. Using the multiplexed tri-mode signal outputs, the PT-Disk can quantify prostate specific antigen with limits of detection of 1.4–2.8 ng mL−1. This is the first attempt to apply the photothermal biosensing principle in portable PMMA/paper-based analytical devices, which offers not only versatile on-chip visual quantitative signal outputs, but also the implementation of the photothermal biosensing principle in a lab-on-a-chip format.
•Application of photothermal biosensing principle in PMMA/paper-based devices.•Development of a novel photothermal immunoassay disk.•Use of a clip-magazine-assembled photothermal biosensing strategy.•Realization of on-chip multiplexed tri-mode visual quantitative signal outputs.•Tri-mode visual quantification of prostate specific antigen (PSA).
The state of charge (SOC) plays a critical role in battery management systems. This paper discusses the stability of the nonlinear SOC observer based on the extended Kalman filter. The model ...characterizing the lithium-ion battery nonlinearity is the basis of the stability analysis. After balancing the accuracy and the complexity of the models, the Thevenin battery model and the logarithmic fitting OCV (open circuit voltage) model are employed. The stability of the SOC observer is theoretically analyzed from two aspects: model parameters and system nonlinearity. Furthermore, the impact of system noises and nonlinear characteristics on the estimation is explored in a numerical way. For the estimation of SOC, the nonlinearity is mainly reflected in the OCV-SOC function. It is found out that the gradient variation of the OCV-SOC curve is not conducive to the estimation, especially when the gradient is small and the voltage noise is large. In order to improve the estimation performance, the role of matrices Q and R as the design parameters of the SOC observer is discussed. The results indicate that the observer is able to exhibit good stability and performance under appropriate settings.
We have studied the organometallic intermediate of a surface-supported Ullmann coupling reaction from 4, 4″-dibromo-p-terphenyl to poly(para-phenylene) by scanning tunneling microscopy/spectroscopy ...and density functional theory calculations. Our study reveals at a single-molecular level that the intermediate consists of biradical terphenyl (ph)3 units that are connected by single Cu atoms through C–Cu–C bridges. Upon further increasing the temperature, the neighboring biradical (ph)3 units are coupled by C–C bonds forming poly(para-phenylene) oligomers while the Cu atoms are released.
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