617 research outputs found

    Graphene Field-Effect Transistor for Terahertz Modulation

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    The real-world applications of terahertz (THz) technology necessitate versatile adaptive optical components, for example, modulators. In this chapter, we begin with a brief review on different techniques for THz modulation. After that, we introduce the extraordinary features of graphene along with its advantages and disadvantages as channel materials for field effect transistor (FET). We then discuss two types of graphene FET-based THz modulators, one is rigid and another is flexible. The feasibility of the high-quality THz modulators with different graphene FET structures has been successfully demonstrated. It is observed that by tuning the carrier concentration of graphene by electrical gating, the THz modulation can be obtained with relatively large modulation depth, broad width band, and moderate speed. This chapter helps the reader in obtaining guidelines for the proper choice of a specific structure for THz modulator with graphene FET

    Research and Development of Automatic Detection Instrument for Stored Grain Fungi

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    Fungus is one of the primary factors endangering the safety of grain storage.The rapid detection of fungi on stored grain in early stage is an effective measure to prevent and control the fungal multiplication and ensure food security.In 2018,an industry standard “LS/T 6132 Inspection of Grain and Oil—Storage fungal examination—Enumeration spores of fungi” was promulgated and implemented in the grain industry.In this study,we developed an automatic detector for the detection of fungi in grain storage to promote the application of this industry standard.During the development of the detector,we built a fungal spore image library based on a large number of stored grain fungal spore pictures,and developed a fungal spore image recognition software using neural network algorithm.By optimizing the auto focusing algorithm of the microscopic imaging system,the fungal spore image under the microscope can be automatically focused and photographed.And the image recognition software was used to recognize and count the spores of the stored grain fungal automatically.This detector can realize the automatic detection of fungi on stored grain and reduce the probability of mistaken in personnel operation and identification

    {1,8-Bis[2-(2-oxidobenzyl­idene­amino)phen­oxy]-3,6-dioxaocta­ne}nitrato­praseodymium(III) trichloro­methane solvate

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    In the title compound, [Pr(C32H30N2O6)(NO3)]·CHCl3, the PrIII ion is ten-coordinated by eight O atoms and two N atoms from the acyclic crown-type Schiff base ligand and the bidentate nitrate group. The coordination polyhedron around PrIII is a distorted bicapped square anti­prism. The chloro­form solvent mol­ecule is not involved either in coordination to the PrIII center or in hydrogen bonding to the complex. The Pr—O(phenolate) bonds are significantly shorter than the Pr—O(ether) and Pr—O(nitrate) bonds, which suggests that the Pr—O(phenolate) bond is stronger than these other bonds. In the crystal structure, the acyclic crown-type Schiff base ligand wraps around the PrIII centre, forming a pseudo-ring
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