Gas sensors for oxides synthesis by hydrothermal and microwave hydrothermal methods

so far, gas sensors are playing an increasingly important role in environmental detection, agricultural production, medical treatment and other fields. Semiconductor oxide gas sensors are often used to detect toxic gases because of their low cost, simple manufacture, fast response, good selectivity and high sensitivity. There are many methods to prepare semiconductor oxides, such as hydrothermal synthesis, microwave hydrothermal synthesis and sol-gel synthesis. The advantages of hydrothermal synthesis and microwave hydrothermal synthesis are high economic efficiency and simple operation. The synthesized oxides have many different morphologies, such as zero dimensional, one-dimensional, two-dimensional, three-dimensional and so on. These diff erent morphologies are conducive to gas diff usion and enhance gas sensing performance. Especially the hierarchical structure can greatly improve the gas sensing performance due to its large specifi c surface area, large porosity and high carrier concentration. This paper describes the SMO gas sensor prepared by hydrothermal method and microwave hydrothermal method

A comparative study on the performance of three color schemes in landscape preference tests

The photo color is recognised as one of the most significant but not fully understood factors influencing the results of landscape preference research. In this context, this paper compares the performances of three photo color schemes (original, rendered and white-black color schemes) frequently used in landscape preference tests to figure out which is the more suitable alternative to an original color photo. Statistics analysis results demonstrated that: 1) In general, the photo color schemes particularly the white-black scheme will significantly affect the results of landscape preference test. Compared with white-black, color in any other forms can increase the degree of preference for a given landscape. 2) The photo color scheme plays a decisive role in respondent’s judgment on some landscape attributes. Original color, White-black color and Rendered color schemes are better suited in landscape preference tests that highlight the effect of color, characteristic and naturalness respectively. 3) When the Rendered color scheme is used as an alternative to the Original color scheme, it has a much better performance than the White-black Color Scheme and is therefore recommended as the prior alternative color scheme to the Original color scheme under most scenarios in landscape preference research. Based on these results, it is suggested that color should be more carefully treated according to its different performance in landscape cognition research

Component analysis and accuracy improvement of linear power flow equation based on Legendre polynomial expansion

The linearization of the power flow equation is widely used in power industry. Existing linearization approaches are generally regarded as nonlinear state variable space transformation, where the original power flow equation can be approximately reformulated as the linear forms in transformed state variable spaces. However, the optimality of linear power flow equations cannot be theoretically compared in different spaces and is only verified based on case studies. In this paper, based on Legendre polynomial expansion, power flow equations are uniformly transformed into a single state variable space, where dimensions correspond to certain orders of Legendre expansion. Through component analysis of power flow equations on each dimension, we find that the accuracy of the linear power flow equation can be improved by formulating an appropriate state variable space transformation to reduce Legendre component loss. Based on this, a linearization method minimizing Legendre component loss is formulated. Compared with the regular case-based linearization, the proposed method does not depend on empirical data, and can theoretically guide the selection of the linear power flow equation within the specified operating bound. The accuracy performance is verified in OPF calculation based on numerous IEEE and Polish test systems