Aqueous battery has been gained much more interest for large-scale energy storage fields due to its excellent safety, high power density and low cost. Cryptomelane-type KMn8O16 confirmed by X-ray diffraction (XRD) was successfully synthesized by a modified hydrothermal method, followed by annealed at 400°C for 3 h. The morphology and microstructure of as-prepared KMn8O16 investigated by field-emission scanning electron microscopy (FE-SEM) with the energy spectrum analysis (EDS) and transmission electron microscopy (TEM) demonstrate that one-dimensional nano rods with the length of about 500 nm constitute the microspheres with the diameter about 0.5~2 μm. The cyclic voltammetry measurement displays that the abundant intercalation of zinc ions on the cathode takes place during the initial discharge process, indicating that cryptomelane-type KMn8O16 can be used as the potential cathode material for aqueous zinc ion batteries. The electrode shows a good cycling performance with a reversible capacity of up to 77.0 mAh/g even after 100 cycles and a small self-discharge phenomenon.
This paper proposes a combined inspection method for thermally damaged concrete under a hygrothermal environment. Experiments were conducted to verify the feasibility of the proposed method. Concrete samples with different water–cement ratios (W/C = 0.3, 0.5, 0.7) and moisture contents (dried, 50% saturated, fully saturated) were exposed to elevated temperatures of 200 °C, 400 °C, 600 °C, and 800 °C for 4 h. After cooling to room temperature, infrared thermal imaging (IRT), ultrasonic pulse velocity (UPV) measurements, and mechanical tests were carried out for the damaged concrete samples. The mechanical behavior of thermally damaged concrete with different degrees of water saturation was examined based on mechanical testing. The results show that water can affect the compressive strength and UPV of concrete under certain circumstances, and the residual strength and the heating temperature of the thermally damaged concrete can be evaluated by IRT and UPV measurements. When 50% saturated concrete specimens with a W/C ratio of 0.3, 0.5, and 0.7 are exposed to 200 °C, 12.6%, 27.4%, and 34.6% increases in normalized compressive strength were observed before dropping to approximately 40% at 800 °C. With various moisture contents, the normalized compressive strength variation can be up to 40% at 400 °C in cases with W/C = 0.5 and 0.7. As for UPV, it generally decreases with the increase in moisture content when the peak temperature is 800 °C. On the contrary, whether concrete is saturated or not, there is little difference in temperature change in IRT detection. To obtain a more precise evaluation of concrete structures, IRT can be used to scan a large area to determine the damaged concrete area and areas suspected to be damaged, while UPV could be used to detect concrete members in suspected areas after the completion of IRT scanning.
Abstract:The article put forward a method on forest-cover monitoring based on high resolution remote sensing data of adjacent two year and existing vector data of forest sub-compartment. With the GF-2 remote sensing image and Rapid-Eye images as the data sources, multi-scale segmentation under the forest land boundary control was conducted, and object of deforestation samples were selected. The object-oriented method of KNN and rules-based were used to classify the image and extract the patches of deforestation. Then we get the deforestation vector diagram of early and later periods. The deforestation patches of two periods were compared and analyzed to achieve the deforestation and recovering vector diagram in a year. Finally, the paper proved the feasibility of the method in forest-cover monitoring application by accuracy analysis.
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