Thickness-Controllable Silica Coating of CdTe QDs by Reverse Microemulsion Method for the Application in the Growth of Rice

Herein, we report the synthesis and surface modification of CdTe quantum dots (QDs) and the application in the rice growth. Water-soluble thioglycolic acid (TGA) stabilized CdTe quantum dots were synthesized firstly and then the surface modification was conducted. II–VI semiconductor nanocrystals prefer to be coated with silica as inert materials to improve their chemical properties. The toxicity of QDs reduced after the modification. Silica coated QDs were used in the growth of rice seed and the effect was discussed. In our knowledge it is the first time we report that the silica coated QDs had nice effect on the growth of rice

Linking PHYTOCHROME-INTERACTING FACTOR to Histone Modification in Plant Shade Avoidance

Shade avoidance syndrome (SAS) allows a plant grown in a densely populated environment to maximize opportunities to access to sunlight. Although it is well established that SAS is accompanied by gene expression changes, the underlying molecular mechanism needs to be elucidated. Here, we identify the H3K4me3/H3K36me3-binding proteins, Morf Related Gene (MRG) group proteins MRG1 and MRG2, as positive regulators of shade-induced hypocotyl elongation in Arabidopsis (Arabidopsis thaliana). MRG2 binds PHYTOCHROME-INTERACTING FACTOR7 (PIF7) and regulates the expression of several common downstream target genes, including YUCCA8 and IAA19 involved in the auxin biosynthesis or response pathway and PRE1 involved in brassinosteroid regulation of cell elongation. In response to shade, PIF7 and MRG2 are enriched at the promoter and gene-body regions and are necessary for increase of histone H4 and H3 acetylation to promote target gene expression. Our study uncovers a mechanism in which the shade-responsive factor PIF7 recruits MRG1/MRG2 that binds H3K4me3/H3K36me3 and brings histone-acetylases to induce histone acetylations to promote expression of shade responsive genes, providing thus a molecular mechanistic link coupling the environmental light to epigenetic modification in regulation of hypocotyl elongation in plant SAS

Structural insights into molecular mechanism for N6-adenosine methylation by MT-A70 family methyltransferase METTL4

METTL4 belongs to a subclade of MT-A70 family members of methyltransferase (MTase) proteins shown to mediate N6-adenosine methylation for both RNA and DNA in diverse eukaryotes. Here, we report that Arabidopsis METTL4 functions as U2 snRNA MTase for N6−2’-O-dimethyladenosine (m6Am) in vivo that regulates flowering time, and specifically catalyzes N6-methylation of 2’-O-methyladenosine (Am) within a single-stranded RNA in vitro. The apo structures of full-length Arabidopsis METTL4 bound to S-adenosyl-L-methionine (SAM) and the complex structure with an Am-containing RNA substrate, combined with mutagenesis and in vitro enzymatic assays, uncover a preformed L-shaped, positively-charged cavity surrounded by four loops for substrate binding and a catalytic center composed of conserved residues for specific Am nucleotide recognition and N6-methylation activity. Structural comparison of METTL4 with the mRNA m6A enzyme METTL3/METTL14 heterodimer and modeling analysis suggest a catalytic mechanism for N6-adenosine methylation by METTL4, which may be shared among MT-A70 family members

Review of Conductive Reciprocating Liquid Metal Magnetohydrodynamic Generators

Reciprocating liquid metal magnetohydrodynamic (MHD) power generation is a new MHD power generation method in which the working fluid is a single-phase liquid metal with a low melting point and high conductivity. The internal combustion stroke of automobiles, ocean waves, sound waves and other reciprocating external forces drive the liquid metal to flow back and forth in an applied magnetic field, generating single-phase alternating current (AC) energy. Reciprocating liquid metal MHD (LMMHD) power generation has the advantages of a high power density, high efficiency, a fast start and good stability, and it provides a new solution for space static nuclear power conversion, variable-stroke automobile engines, distributed power supply and ocean energy utilization. According to the mode of action of an electromagnetic field, reciprocating LMMHD generators can be divided into the inductive type and conductive type. Compared with the inductive type, the conductive type has a simple structure and is the current research hot spot. Firstly, the classification and characteristics of reciprocating LMMHD power generation are introduced. Then, the working characteristics of conductive reciprocating LMMHD (CRLMMHD) generators are analyzed. On this basis, technical key points and issues in the current research of CRLMMHD generators are elaborated. Finally, conclusions and the future research direction of CRLMMHD generators are pointed out

Wave Energy Conversion Technology Based on Liquid Metal Magnetohydrodynamic Generators and Its Research Progress

Wave energy is a highly concentrated energy resource with five times higher energy density than wind and at least ten times the power density of solar energy. It is expected to make a major contribution to addressing climate change and to help end our dependency on fossil fuels. Many ingenious wave energy conversion methods have been put forward, and a large number of wave energy converters (WECs) have been developed. However, to date, wave energy conversion technology is still in the demonstration application stage. Key issues such as survivability, reliability, and efficient conversion still need to be solved. The major hurdle is the fact that ocean waves provide a slow-moving, high-magnitude force, whereas most electric generators operate at high rotary speed and low torque. Coupling the slow-moving, high-magnitude force of ocean waves normally requires conversion to a high-speed, low-magnitude force as an intermediate step before a rotary generator is applied. This, in general, tends to severely limit the overall efficiency and reliability of the converter and drives the capital cost of the converter well above an acceptable commercial target. Magnetohydrodynamic (MHD) wave energy conversion makes use of MHD generators in which a conducting fluid passes through a very strong magnetic field to produce an electric current. In contrast to alternatives, the relatively slow speed at which the fluid traverses the magnetic field makes it possible to directly couple to ocean waves with a high-magnitude, slowly moving force. The MHD generator provides an excellent match to the mechanical impedance of an ocean wave, and therefore, an MHD WEC has no rotating mechanical parts with high speeds, no complex control process, and has good response to low sea states and high efficiency under all working conditions. This review introduces the system composition, working process, and technical features of WECs based on MHD generators first. Then, the research development, key points, and issues of wave energy conversion technology based on MHD generators are presented in detail. Finally, the problems to be solved and the future research directions of wave energy conversion based on MHD generators are pointed out

Analysis of Different Winding Configuration on Electromagnetic Performance of Novel Dual Three-Phase Outer-Rotor Flux-Switching Permanent Magnet Machine for Oscillating Water Column Wave Energy Generation

In this article, we propose, for the first time, to apply the flux-switching permanent magnet (OR-FSPM) generator to the oscillating water column wave energy conversion (OWC-WEC), and a novel dual three-phase 24-slot/46-pole OR-FSPM generator for OWC-WEC is designed and analyzed. The feasible phase-shift angle (PH-Angle) between the two sets of windings, namely 0°, 30° and 60°, is analyzed. The electromagnetic performance of the generator under three winding configurations is investigated, including PM flux linkage, back electromotive force (EMF), open-circuit rectified voltage, inductance, cogging torque, electromagnetic torque and unbalanced magnetic force (UMF). The prototype is manufactured, and the experimental results are consistent with that of the finite-element analysis (FEA) results. The generator with 0° and 60° PH-Angle winding configuration has stronger fault tolerance. When the 30° PH-Angle winding configuration is adopted, it has the maximum back-EMF fundamental amplitude, maximum average electromagnetic torque and the minimum torque ripple, and there is no UMF when a single set of windings is running. Therefore, the proposed novel OR-FSPM generator with 30° PH-Angle winding configuration is more suitable for OWC-WEC

Effect of Inlet Flow-Guide on Hydraulic Loss of Seawater MHD Propeller with Helical Channel

Abstract Inlet flow-guide is very important to the hydraulic loss of the whole channel of marine MHD thruster with helical channel. In this paper, variable helix is used as the line-type of flow-guide blade, and helical loop number (N), blade number (n) and blade height (H) (helix height) are established as the main geometric parameters. L 16 (43) orthogonal table was used to design the inlet flow-guide, which contains three factors with four levels of N, n and H. The whole flow filed of helical channel with inlet flow-guide was numerical simulated with Fluent. The results show that the hydraulic loss of the helical channel can be greatly reduced by the inlet flow-guide; The results of orthogonal experimental show that the hydraulic loss of the helical channel is sensitive to the line-type of the guide vane, and the total hydraulic loss increases with the increase of n, increases first and then decreases with the increase of N, and decreases first and then increases with the increase of H.</jats:p

Thickness-Controllable Silica Coating of CdTe QDs by Reverse Microemulsion Method for the Application in the Growth of Rice

Herein, we report the synthesis and surface modification of CdTe quantum dots (QDs) and the application in the rice growth. Water-soluble thioglycolic acid (TGA) stabilized CdTe quantum dots were synthesized firstly and then the surface modification was conducted. II–VI semiconductor nanocrystals prefer to be coated with silica as inert materials to improve their chemical properties. The toxicity of QDs reduced after the modification. Silica coated QDs were used in the growth of rice seed and the effect was discussed. In our knowledge it is the first time we report that the silica coated QDs had nice effect on the growth of rice

Research on the High Reliable Electromagnetic Stirring Power Supply

A reconstructed topology with fault diagnosis and fault-tolerant control strategy of the two-phase quadrature power supply of an electromagnetic stirring system are proposed to improve the reliability of the system. First, if the back stage inverter is faulty, the topology will be reconstructed after the diagnosed fault. The reconstructed topology with the fault diagnosis can be applied twice. Additionally, a fault pulse reset method is proposed to form a fault-tolerant control strategy, for which the high-reliability electromagnetic stirring power supply does not need to switch the control algorithm before and after the failure. The reliability of the electromagnetic stirring power supply is improved greatly. Finally, simulations and experiments verify the correctness of the electromagnetic stirring power supply fault diagnosis algorithm, reconstruction topology, and its fault-tolerant control strategy proposed in this paper.</jats:p