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In this paper we establish a new on-diagonal lower estimate of heat kernels for connected, weighted, locally finite graphs. The result is then used to deal with the nonexistence of global solutions for a semilinear heat equation on locally finite graphs. Our results provide remarkable improvements to the work that was done recently by Lin and Wu (2017) [8,18]. [ABSTRACT FROM AUTHOR]

In this work, the TiO 2 nanorod arrays (TNAs), TNAs/Cu 2 O-10CYC, and TNAs/Cu 2 O-30CYC composites photo-catalysts for solar water splitting anode was successfully prepared via cyclic impregnation growth method. The structure, surface morphology and element chemical states have been investigated and discussed in detail. The UV–vis and PL results confirm that interaction has been formed between TNAs and Cu 2 O in the composite photo-catalysts and the TNAs/Cu 2 O composites exhibit broad spectrum absorption. Three factors affecting on the enhancement of solar light hydrogen production efficiency, e.g. enhanced UV-light absorption in solar spectrum, massive charge carrier generation and improved surface-interface reaction due to the absorbing visible light by the narrow band gap Cu 2 O and the injecting electrons into TiO 2 conduction band, are proposed based on the experimental results. The TNAs/Cu 2 O-10CYC composite samples exhibit highest enhanced photocatalytic activities in the hydrogen production, which H 2 evolution efficiency is about 4-fold higher than that of pure TNAs. It indicates that the efficient photo generated electron-hole transformation and separation in TNAs/Cu 2 O-10CYC composite sample leads to the improvement of photocatalytic performance. The present study provides a new light to prepare TNAs/Cu 2 O of novel configuration with promising potential applications. [ABSTRACT FROM AUTHOR]

In addition to being historically intentionally manufactured as commercial products, polychlorinated biphenyls (PCBs) can be unintentionally released as by-products from industrial processes. Recent studies have emphasized the importance of unintentionally produced PCBs (UP-PCBs) and have even identified them as major contributors to atmospheric PCBs. However, little is known about contributions of UP-PCBs in current soils. In this study, all 209 PCB congeners were analyzed in agricultural soils on a national scale to investigate the influence of unintentional sources on Chinese soil. The concentration of Σ 209 PCBs in soils across China was in the range of 64.3–4358 pg/g. Four non-Aroclor congeners, i.e., PCB11, PCB44 + 47+65, PCB68, and PCB209, were dominant among all PCBs, averagely accounting for 26.3%, 8.83%, 3.03%, and 2.80% of total PCBs, respectively. PCB11 and PCB209 were found to be higher in East China, while PCB44 + 47+65 and PCB68 were higher in South China. Their spatial distributions were largely dependent on local sources. The results of source apportionment indicated that the legacy of historically produced and used commercial PCB mixtures was the dominant contributor to seven indicator PCBs in Chinese agricultural soils, especially high-chlorinated congeners. However, unintentional sources (i.e., pigment/paint, combustion-related sources, and polymer sealant), which contributed 57.4% of the total PCBs, are controlling PCB burdens in agricultural soils across China. Image 1 • A complete analysis of 209 PCBs were conducted in agricultural soils across China. • PCB11, PCB44 + 47+65, PCB68, and PCB209 were dominant congeners among all 209 PCBs. • The spatial distributions of non-Aroclor congeners were dependent on local sources. • The 7 indicator PCBs were dominated (52%) by the legacy commercial products. • Unintentional sources were the dominant contributor (57%) of the total PCBs in soils. The main finding of this work : PCBs in Chinese agricultural soils were dominated by non-Aroclor congeners. Unintentional sources contributed 57% of the total PCBs in soils. [ABSTRACT FROM AUTHOR]

An experiment was carried out to study the buckling and post-buckling behavior of stiffened composite curved panel under shear and in-plane bending. A test fixture was designed uniquely which was suitable for curved panel subjected to shear or shear and in-plane bending. The results showed that this kind of fixture was feasible. The strain data were recorded by strain gauges. The out-of-plane displacement field was characterized by a 3D digital speckle system. The stability of stiffened composite curved panel subjected to shear and in-plane bending was analyzed by the obtained data. Finite element method (FEM) was used. The influence of transverse frames on the stability of stiffened curved panel was further studied by FEM. Good correlation between experimental and FEM analysis was obtained. The fixture and test method used in this paper provide a reference to the study of curved panel subjected to shear or shear and in-plane bending. [ABSTRACT FROM AUTHOR]