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La1-xCaxMnO3, as a candidate for thermal radiation detectors, has received more attention due to the quest for a higher temperature coefficient of resistance (TCR), however, the narrow high-TCR temperature range greatly limits its application in uncooled bolometer. In this paper, Mn3O4 - La1-xCaxMnO3 (x = 0–0.33) composite ceramics were prepared using the sol-gel method. A suitable TCR was achieved over a wide temperature range, including room temperature, by adjusting the Ca content. As the Ca content decreased, the resistivity (ρ) of the composite gradually increased at 300 K, and the positive TCR (PTC) peak shifted to a lower temperature. However, the negative TCR (NTC) was enhanced over a wider temperature range. When x = 0.05, the maximal NTC was −3.2%·K−1 within the range of 172 K–350 K and |TCR| > 2%·K−1, spanning a large temperature range around 180 K, including room temperature. These results strongly indicate that the composite, such as Mn3O4 - La1-xCaxMnO3, provides a new idea for uncooled bolometer/night vision. Highlights: Mn3O4 - La1-xCaxMnO3 composite ceramics with better density were prepared by sol-gel method. When x = 0.05, the sample Mn3O4 - La0.95Ca0.05MnO3 has a maximum |TCR| of −3.2%·K−1 in the range of 172 K–350 K, spanning the temperature range of about 180 K including room temperature. The wide temperature range and significant |TCR| values observed in the Mn3O4 - La1-xCaxMnO3 composite ceramics provide suitability for uncooled infrared bolometer applications under large temperature fluctuations. [ABSTRACT FROM AUTHOR]

The situation of global water crisis is becoming more and more serious[1]. Due to the inconvenience of fresh water carrying or long-term storage and deterioration, the personnel and equipment of oceangoing ships are in urgent need of fresh water resources[2]. However, the traditional seawater desalination technology will consume fossil energy or its economy is not high. Under the background of a series of green ship development plans, people focus on green clean energy to solve the problem of fresh water shortage[3]. Interfacial photoevaporation is an effective strategy to promote seawater desalination and pollutant treatment. Photothermal conversion materials and evaporators have shown their good performance in improving seawater desalination efficiency. In this paper, the photohot water gel prepared by calcium chloride, polyvinyl alcohol, sodium citrate, tannic acid and ferric chloride was used as the photothermal conversion material[4]. The properties of photoevaporative seawater desalination materials were studied by a series of instruments such as optical microscope and contact Angle measuring instrument. The experimental results show that the flower-like hydrogel has high photothermal conversion efficiency and has a good application prospect in green Marine desalination field.

Simultaneously increasing the temperature coefficient of resistivity (TCR) and low-field magnetoresistance (LFMR) has become important. Generally, Mn ions play an important role in the change of electromagnetic properties of the system, and the change of Mn3+/Mn4+ causes the J-T effect and DE interaction. In this paper, (La0.7Ca0.3MnO3)1-x: (MnO2)x(x = 0–0.2) ceramics are prepared by sol-gel and solid-state routine. The morphology, structure, and transport properties are studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectra (XPS), and four-probe technique test methods. The XRD results show that all samples have high crystallinity and density, and the structure (space group) are determined to be Pnma. The SEM grain statistics diagram results show that with the increase of MnO2, the grain size increases and grain boundary decreases. The XPS shows that Mn4+ ions content increases first and then decreases. Moreover, the electrical and magnetic transport properties of the samples are improved, resistivity(ρ), TCR increased from 39.89 to 44.29%·K−1, MR increased from 53.29 to 75.42%, which is larger than most of the other reported values and provides a new direction for the selection of infrared detection materials. Highlights: (La0.7Ca0.3MnO3)1-x:(MnO2)x(x = 0,0.04,0.08,0.12,0.2) composite were prepared by sol-gel and solid-state routine. By adding MnO2, the structural, electrical and magnetic transport properties of La0.7Ca0.3MnO3 were studied. Both the temperature coefficient of resistance (TCR) and low-field magnetoresistance (LFMR) were greatly enhance. Electrical and magnetic transport properties were investigated and discussed on the basis of the Jahn-Teller (JT) effect and double-exchange (DE) mechanism. [ABSTRACT FROM AUTHOR]