Nowadays glucose detection is of great importance in the fields of biological, environmental, and clinical analyzes. In this research, we report a zinc oxide (ZnO) nanorod powder surface-coated with carbon material for non-enzymatic glucose sensor applications through a hydrothermal process and chemical vapor deposition method. A series of tests, including crystallinity analysis, microstructure observation, and electrochemical property investigations were carried out. For the cyclic voltammetric (CV) glucose detection, the low detection limit of 1 mM with a linear range from 0.1 mM to 10 mM was attained. The sensitivity was 2.97 μA/cm2mM, which is the most optimized ever reported. With such good analytical performance from a simple process, it is believed that the nanocomposites composed of ZnO nanorod powder surface-coated with carbon material are promising for the development of cost-effective non-enzymatic electrochemical glucose biosensors with high sensitivity.

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Keywords:Average X-ray strain (AXS) Average effective X-ray elastic constant (AEXEC) Cos 2 αsin 2 ψ method High energy X-ray Laser curvature method TiN hard coating For stress measurement on thin films and coatings using X-ray diffraction (XRD) methods, the uncertainty is commonly acknowledged to be from elastic constants. However, the uncertainty can be due to the statistical fluctuation of strain measured by XRD. In this study, we proposed a method where the average X-ray strain (AXS) was determined using cos 2 αsin 2 ψ XRD technique at several rotational (ϕ) angles to improve the accuracy of the measurement of X-ray stress or X-ray elastic constants (XECs). The major concept was to increase sampling volume by measuring X-ray strain at multiple rotational angles. TiN hard coating on Si (100) substrate was selected as the model system, where the residual stress was determined by laser curvature technique and the accompanying lattice strain was measured by cos 2 αsin 2 ψ method. The average effective elastic constant (AEXEC) could be attained by substituting the residual stress into the slope of AXS vs. cos 2 αsin 2 ψ plot. The AEXEC was served as an indicator to validate the AXS measurement. By substituting AEXEC in conventional sin 2 ψ XRD stress measurement, the deviation of the result from the stress obtained by laser curvature method was less than 7%, indicating that AXS effectively reduced the uncertainty in XECs and thus increased the accuracy of stress measurement. The concept of increasing sampling volume was also confirmed using synchrotron X-ray source, where the statistical fluctuation in X-ray strain could be further reduced by performing the measurement at all azimuthal direction. The experimental results showed that the uncertainty on XEC measurement by sin 2 ψ method was less than 10%, if sufficient sampling volume was provided. Furthermore, using AXS and elastic constant measured by nanoindentation (E NIP ) to calculate X-ray stress, the stress deviation from that by laser curvature method could be substantially reduced even down to 3% with sufficient sampling points. Therefore, AXS may serve as a convenient parameter, when combining with E NIP , in X-ray stress measurement, by which residual stress of hard coatings comparable to that by laser curvature method can be obtained without using XECs.

Abstract. Reclaimed soil aggregates play a critical role in the accumulation of soil organic carbon. The purpose of this article is to investigate the effects of reclaimed soil aggregate development on organic carbon and explore changes in reclaimed agricultural soil over time in a coal mining subsidence area. Adjacent to the control sample plot (CKN), six sample plots of different reclamation time series: 2001 (R15), 2003 (R13), 2005 (R11), 2007 (R9), 2009 (R7), and 2011 (R5) were collected. Soil analyses included aggregate fractionation and organic carbon. Over time, the distribution characteristics of water-stable aggregates in reclaimed soil gradually improved. The concentration of organic carbon in reclaimed soil increased with aggregate size, and the organic carbon concentration of all aggregates increased with reclamation age. As the number of reclamation years increased, organic carbon also increased, first in the free light fraction (fLF) and later in mineral-bound carbon (mineral-C). Accumulation of organic carbon was related to the development of soil aggregates. The formation and carbon sequestration of reclaimed soil aggregates was consistent with the conceptual model of “aggregate turnover.” The transformation and accumulation of organic carbon was consistent with the physical protection mechanism of soil organic carbon. Keywords: Aggregate, Coal mining subsidence area, Reclaimed soil, Soil organic carbon.

In this study, a biosensor, based on a glucose oxidase (GOx) immobilized, carbon-coated tin sulfide (SnS) assembled on a glass carbon electrode (GCE) was developed, and its direct electrochemistry was investigated. The carbon coated SnS (C-SnS) nanoparticle was prepared through a simple two-step process, using hydrothermal and chemical vapor deposition methods. The large reactive surface area and unique electrical potential of C-SnS could offer a favorable microenvironment for facilitating electron transfer between enzymes and the electrode surface. The structure and sensor ability of the proposed GOx/C-SnS electrode were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), and cyclic voltammetry study (CV).