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Objective: In order to achieve rapid detection of methyl parathion. Methods: An acetylcholinesterase sensor was prepared based on gold nanoparticles and reduced graphene oxide for quantitative detection of Methyl parathion. Reduced graphene oxide, gold nanoparticles and acetylcholinesterase were successively modified on the surface of the screen printing electrode by layer-by-layer assembly method. The catalytic activity and impedance characteristics of the sensor, the relationship between the sensor's inhibition rate and MP concentration, and the actual sample detection were evaluated. Results: The prepared acetylcholinesterase biosensors showed excellent affinity for acetylthiocholine chloride with the Michaelis-Menten constant of 2.76 mmol/L. Under the optimal conditions, Methylparathion could be effectively detected with a linear range of 5 ng/mL to 500 ng/mL and a detection limit of 0.692 ng/mL. Conclusion: The method is simple, practical and stable. It provides a reliable method for rapid detection of organophosphorus pesticides.

Silicon-based optical switch is one of the key components for on-chip optical interconnect systems, and mode division multiplexing technology has been employed to boost optical switches’ channel capacity. However, the majority of the proven multimode optical switches have a switching time in the microsecond range, which is insufficient for some applications. In this paper, we design and experimentally demonstrate a high-speed dual-mode 4 × 4 optical switch based on a mode-diversity scheme, composed of four pairs of mode multiplexers and de-multiplexers, and two optimized single-mode 4 × 4 optical switches. Fast switching is enabled based on the carrier dispersion effect. At the same time, we improve the performances of the optical switch by reducing the number of optical switch units used in the 4 × 4 Spanke–Beneš architecture. Its power consumptions are reduced by ∼17%. Its insertion losses are within 8.8 dB in the wavelength range of 1525–1565 nm in the both sates of “through” and “all-cross”, while the optical signal-to-noise ratios are larger than 12.8 dB. Also, 50 Gbps data transmission experiments verify the device’s data transmission functionality.

Molecule self-assembly on the surface of alumina ceramic and its influence on the surface flashover characteristics of the alumina ceramic insulators were studied in this paper. First, octadecyltrichlorosilane was assembled on the surface of alumina ceramic insulators in the toluene solution. Then, 393 K thermal treatment of 2 h was conducted on the specimens to promote the growth of the molecule membrane. Quality detection of the prepared molecule membrane by Energy Dispersive x-ray Analysis and water contact angle test showed that the molecules were linked to the alumina surface and the arrangement of the molecules on the surface was regular and tight. Gas release characteristic suggested that the formation of the molecule membrane made the gas release rate of the treated alumina decrease. The flashover voltage test on the home-made, short-pulsed, high-voltage vacuum platform indicated that the flashover voltages of the treated insulators increased by over 200% compared with the original alumina insulators. These results indicated that a layer of regular molecule membrane was formed on the surface of alumina through molecule self-assembly, which could improve the surface voltage withstand strength of the treated insulators. [ABSTRACT FROM AUTHOR]

A Ku band coaxial high power microwave generator with a low magnetic field was investigated without mode competition in this paper. Mode competition is avoided physically by adopting a two-cavity extractor instead of a three-cavity extractor to eliminate the resonance between the modulation slow wave structure and the extractor slow wave structure at any unexpected frequency except the working frequency. Moreover, the efficiency of the device increases due to the separation process of energy extraction and electron collection by adopting the inner conductor collecting structure. Particle simulation results showed that when the magnetic flux density is 0.6 T, the diode voltage is 560 kV, and the diode current is 8 kA, we get 1.55 GW microwaves with an efficiency of 35% and a frequency of 14.7 GHz. Experimental investigation is carried out based on the physical design and simulation results. 1.0 GW microwaves are obtained, and the frequency is 14.8 GHz in the experiment when the magnetic flux density is 0.64 T, the diode voltage is 590 kV, and the diode current is 8.5 kA. No obvious hint of electron emission or bombardment is observed at the surface of the generator after 10 thousand pulses, and the advantage of this kind of generator working in a low magnetic field is proved. [ABSTRACT FROM AUTHOR]