Abstract: Disclosed in the present application are a concrete protection material, and a preparation method and a construction method therefor. The concrete protection material consists of 50%-90% of a component A and 10%-50% of a component B in percentage by weight, where the component A is prepared from 30%-65% of organic silicon, 2%-5% of nano-silicon dioxide and the balance of an organic solvent in percentage by weight; and the component B is prepared from 20%-50% of an organic base and the balance of water in percentage by weight. The present application not only can form nano-particles having a strengthening effect in capillary channels of a concrete surface layer, but also can achieve a technical effect of superhydrophobicity on the concrete surface layer.

Abstract: A photovoltaic power generation system includes a single-stage inverter, an anti-backflow circuit, a photovoltaic string, and a coupling capacitor. The anti-backflow circuit is connected to one input end of the single-stage inverter, one output end of the photovoltaic string is connected to the other input end of the single-stage inverter, and the other output end of the photovoltaic string is connected to the anti-backflow circuit. The photovoltaic string includes a buck optimizer and a photovoltaic panel. The anti-backflow circuit is configured to prevent a backflow current from flowing back to the photovoltaic string. The coupling capacitor is connected in parallel to two ends of the anti-backflow circuit and is configured to transmit a signal between each buck optimizer in the photovoltaic string and the single-stage inverter, to control backflow of the backflow current when the anti-backflow circuit fails.

Abstract: An automatic test device and method for auditory brainstem response (ABR) collects an ABR dataset at a plurality of sound loudness levels, increases the times of level averaging by iteration based on an adaptive average method, and improves a signal-to-noise ratio until ABR signal detection conditions are met. Signal detection includes determining that the time lag between average curves obtained from the ABR dataset is within a specified range. Iteration is terminated when the ABR signal is detected or a maximum number of iterations is reached. A minimum loudness level required to detect the ABR signal is used as a hearing threshold. An accurate loudness level corresponding to the hearing threshold is obtained by function fitting on the number of iterations used at each loudness level and interpolation. The threshold detection can effectively reduce the number of times that an ABR recording needs to be acquired.

Abstract: The present invention discloses a compact integrated deuterium-deuterium (D-D) neutron generator. A hemispherical metal head is disposed inside a cylindrical ceramic shell of the generator and is provided therein with an ion source and an ion source power supply. An inner ceramic insulated cylinder and an outer ceramic insulated cylinder are disposed between a metal plate of the metal head and a baseplate of the generator, and an isolated power supply system and a high-voltage power supply are disposed between the inner ceramic insulated cylinder and the outer ceramic insulated cylinder. A rear end of an extraction accelerating electrode disposed inside the inner ceramic insulated cylinder protrudes from the generator and is then connected to a target holder disposed outside the baseplate. A target is disposed inside the target holder, the target is at ground potential, and a cooling water interface is disposed on the target holder.

Abstract: The present invention discloses a compact integrated deuterium-deuterium (D-D) neutron generator. A hemispherical metal head is disposed inside a cylindrical ceramic shell of the generator and is provided therein with an ion source and an ion source power supply. An inner ceramic insulated cylinder and an outer ceramic insulated cylinder are disposed between a metal plate of the metal head and a baseplate of the generator, and an isolated power supply system and a high-voltage power supply are disposed between the inner ceramic insulated cylinder and the outer ceramic insulated cylinder. A rear end of an extraction accelerating electrode disposed inside the inner ceramic insulated cylinder protrudes from the generator and is then connected to a target holder disposed outside the baseplate. A target is disposed inside the target holder, the target is at ground potential, and a cooling water interface is disposed on the target holder.