Abstract: The present disclosure provides a gas analysis device and a method for detecting sample gas. The gas analysis device includes: an ion mobility spectrometer including an ion mobility tube, an ion gate, a plurality of electrodes, a suppression grid, and a Faraday plate sequentially disposed in the ion mobility tube, wherein the Faraday plate is configured to receive sample ions discharged from the suppression grid, and the Faraday plate is provided with a through hole; a mass spectrometer; a gate valve disposed between the Faraday plate and an ion inlet of the mass spectrometer; and a controller configured to control an opening or closing of the gate valve to allow the sample ions discharged from the suppression grid to flow into the mass spectrometer through the through hole of the Faraday plate when the gate valve is opened.

Abstract: A method for preparing (S)-nicotine by reduction includes conducting a reduction process on an alkene compound as shown in Formula I and/or an iminium cation compound as shown in Formula II, thereby producing (S)-nicotine. The method is simple, safe, reliable, and yields both high purity and high quantities of (S)-nicotine production.

Abstract: An optical projection screen and a management system thereof are provided. The optical projection screen comprises an LED display module, a cooling module and an optical projection curtain. The optical projection curtain adheres to the LED display module with optical UV glue and is disposed on the light-emitting side of the LED display module. The cooling module is disposed on the backlight side of the LED display module and comprises a plurality of cooling assemblies distributed in different areas and used for cooling different areas of the LED display module. Each cooling assembly comprises a semiconductor refrigeration module, a temperature sensor and an intelligent switch. The intelligent switches control on-off of the semiconductor refrigeration modules according to the temperature detected by the temperature sensors. Multiple modules can be spliced to achieve large-screen display.

Abstract: An optical projection screen and a management system thereof are provided. The optical projection screen comprises an LED display module, a cooling module and an optical projection curtain. The optical projection curtain adheres to the LED display module with optical UV glue and is disposed on the light-emitting side of the LED display module. The cooling module is disposed on the backlight side of the LED display module and comprises a plurality of cooling assemblies distributed in different areas and used for cooling different areas of the LED display module. Each cooling assembly comprises a semiconductor refrigeration module, a temperature sensor and an intelligent switch. The intelligent switches control on-off of the semiconductor refrigeration modules according to the temperature detected by the temperature sensors. Multiple modules can be spliced to achieve large-screen display.