作者机构：
[Jonathan R.Adsetts; 杨柳青; 丁志峰; Darshil Patel; Kenneth Chu; Brian L.Pagenkopf; 张丛洋] Department of Chemistry, Western University;湖南农业大学化学与材料科学学院;凯莱英医药集团(天津)股份有限公司北京分公司;[覃晓丽] Department of Chemistry, Western University<&wdkj&>湖南农业大学化学与材料科学学院;[王鑫] Department of Chemistry, Western University<&wdkj&>凯莱英医药集团(天津)股份有限公司北京分公司
作者机构：
[杨海君] College of Plant Protection, Hunan Agricultural University, Changsha, 410128, China;[邓蓉蓉] College of Science, Hunan Agricultural University, Changsha, 410128, China;[谭菊; 易勇] Changsha Environmental Monitoring Center Station, Changsha, 410001, China
通讯机构：
[Tan, J.] C;Changsha Environmental Monitoring Center StationChina
摘要：
The pursuit for batteries with high specific energy provokes the research of high-voltage/capacity cathode materials with superior stability and safety as the alternative for lithium iron phosphate. Herein, using the sol-gel method, a lithium vanadium phosphate with higher average discharge voltage (3.8 V, vs. Li~+/Li) was obtained from a single source for Mg~(2+) and Cl~- co-substitution and uniform carbon coating, and a nearly theoretical capacity (130.1 mA h g~(-1)) and outstanding rate performance (25 C) are acquired together with splendid capacity retention (80%) after 650 cycles. This work reveals that the well-sized anion and cation substitution and uniform carbon coating are of both importance to accelerate kinetic performance in the context of nearly undisturbed crystal structure for other analogue materials. It is anticipated that the electrochemistry comprehension will shed light on preparing cathode materials with high energy density in the future.
摘要：
Blue-violet light can not only enhance the total content of biomass and glucoside but also enrich the taste of the fruit. Thus, it is meaningful to study the blue-violet luminescent materials for plant cultivation. In this study, titanium (IV) -activated CaYAlO4 (CYAO) phosphors were synthesized by conventional high-temperature solid-state reaction. X-ray powder diffraction was employed to analyze the crystal-structure of CYAO. It is found that the doped Ti4+ ions do not change obviously the crystal structure of phosphors. Upon 246 nm excitation, CaYAl1-xO4:xTi(4+) phosphors exhibit broad blue-violet emission band peaking at 395 nm, which can be attributed to the charge transfer of Ti4+-O2-. Moreover, this phosphor exhibits strong thermal stability. The luminescence emission intensity at 150 degrees C maintained about 91 mol% of its initial value at room temperature. Additionally, the electron transition process and concentration quenching mechanism of CaYAl1-xO4:xTi(4+)are discussed in detail. The excellent luminescent properties indicate that CaYAl1-xO4:xTi(4+) phosphor may have promising application in indoor plant cultivation. Published by Elsevier B.V. on behalf of Chinese Society of Rare Earths.
关键词：
integral equations;Lane-Emden system;conformal invariance;positive solutions;existence
摘要：
This paper is devoted to studying the existence of positive solutions for the following integral system
$$\left\{ {\begin{array}{*{20}{c}}
{u\left( x \right) = \int_{{\mathbb{R}^n}} {{{\left| {x - y} \right|}^\lambda }{v^{ - q}}\left( y \right)dy,} } \\
{v\left( x \right) = \int_{{\mathbb{R}^n}} {{{\left| {x - y} \right|}^\lambda }{u^{ - p}}\left( y \right)dy,} }
\end{array}} \right.p,q > 0,\lambda \in \left( {0,\infty } \right),n \geqslant 1$$
. It is shown that if (u, v) is a pair of positive Lebesgue measurable solutions of this integral system, then
$$\frac{1}{{p - 1}} + \frac{1}{{q - 1}} = \frac{\lambda }{n}$$
, which is different from the well-known case of the Lane-Emden system and its natural extension, the Hardy-Littlewood-Sobolev type integral equations.
摘要：
Recent advances in the preparation and application of perovskite-type oxides as bifunctional electrocatalysts for oxygen reaction and oxygen evolution reaction in rechargeable metal-air batteries are presented in this review. Various fabrication methods of these oxides are introduced in detail, and their advantages and disadvantages are analyzed. Different preparation methods adopted have great influence on the morphologies and physicochemical properties of perovskite-type oxides. As a bifunctional electrocatalyst, perovskite-type oxides are widely used in rechargeable metal-air batteries. The relationship between the preparation methods and the performances of oxygen/air electrodes are summarized. This work is concentrated on the structural stability, the phase compositions, and catalytic performance of perovskite-type oxides in oxygen/air electrodes. The main problems existing in the practical application of perovskite-type oxides as bifunctional electrocatalysts are pointed out and possible research directions in the future are recommended.
摘要：
Hydrogenotrophic denitrification is promising for tertiary nitrogen removal from municipal wastewater. To reveal the influence of residual organics in municipal wastewater on hydrogenotrophic denitrifiers, we adopted high-throughput 16S rRNA gene amplicon sequencing to examine microbial communities in hydrogenotrophic denitrification enrichments. Using effluent from a municipal wastewater treatment plant as water source, COD, nitrate and pH were controlled the same except for a gradient of biodegradable carbon (i.e., primary effluent (PE), secondary effluent (SE), or combined primary and secondary effluent (CE)). Inorganic synthetic water (IW) was used as a control. Hydrogenophaga, a major facultative autotroph, accounted for 17.1%, 5.3%, 32.7% and 12.9% of the sequences in PE, CE, SE and IW, respectively, implicating that Hydrogenophaga grew well with or without organics. Thauera, which contains likely obligate autotrophic denitrifiers, appeared to be the most dominant genera (23.6%) in IW and accounted for 2.5%, 4.6% and 8.9% in PE, CE and SE, respectively. Thermomonas, which is related to heterotrophic denitrification, accounted for 4.2% and 7.9% in PE and CE fed with a higher content of labile organics, respectively. In contrast, Thermomonas was not detected in IW and accounted for only 0.6% in SE. Our results suggest that Thermomonas are more competitive than Thauera in hydrogenotrophic denitrification with biodegradable organics. Moreover, facultative autotrophic denitrifiers, Hydrogenophaga, are accommodating to residual organic in effluent wastewater, thus we propose that hydrogenotrophic denitrification is amenable for tertiary nitrogen removal.
摘要：
A mild and simple synthesis process for large-scale vanadium redox flow batteries (VRFBs) energy storage systems is desirable. A graphite felt/MnO_2 (GF-MNO) composite electrode with excellent electrocatalytic activity towards VO~(2+)/VO~(2 +) redox couples in a VRFB was synthesized by a one-step hydrothermal process. The resulting GF-MNO electrodes possess improved electrochemical kinetic reversibility of the vanadium redox reactions compared to pristine GF electrodes, and the corresponding energy efficiency and discharge capacity at 150 mA cm~(-2) are increased by 12.5% and 40%, respectively. The discharge capacity is maintained at 4.8 A h L~(-1) at the ultrahigh current density of 250 mA cm~(-2). Above all, 80% of the energy efficiency of the GFMNO composite electrodes is retained after 120 charge-discharge cycles at 150 mA cm~(-2). Furthermore, these electrodes demonstrated that more evenly distributed catalytic active sites were obtained from the MnO_2 particles under acidic conditions. The proposed synthetic route is facile, and the raw materials are low cost and environmentally friendly. Therefore, these novel GFMNO electrodes hold great promise in large-scale vanadium redox flow battery energy storage systems.
