Abstract: A method for testing a lifetime of a surface state carrier of a semiconductor, including the following steps, 1) a narrow pulse light source is used to emit a light pulse, and coupled to an interior of a near-field optical probe, and the near-field optical probe produces a photon-generated carrier on a surface of a semiconductor material under test through excitation. 2) The excited photon-generated carrier is concentrated on the surface of the semiconductor material, and recombination is conducted continuously with a surface state as a recombination center. 3) A change in a lattice constant is produced due to an electronic volume effect, a stress wave is produced, and a signal of the stress wave is detected in a high-frequency broadband ultrasonic testing mode. 4) Fitting calculation is conducted on the signal of the stress wave to obtain the lifetime of the surface state carrier ?c.

Abstract: A commodity recommendation system based on actionable high utility negative sequential rules mining and its working method comprises information acquisition module, commodity recommendation module, and commodity sales module that are sequentially connected, with the information acquisition module used to extract and store in real time the customer behavior data and transmit the data to the commodity recommendation module; the commodity recommendation module used to conduct data cleaning for the collected customer behavior data and classify the data after such cleaning and analyze and forecast the customers' shopping behaviors following the process as follows: create a shopping behavior sequence corresponding to the customer ID and the shopping behavior data of customers of the same sex and in the same age range constitute a sequence database, and conduct data mining for the sequence database to get desirable actionable high utility negative sequential rules.

Abstract: A method for testing a lifetime of a surface state carrier of a semiconductor, including the following steps, 1) a narrow pulse light source is used to emit a light pulse, and coupled to an interior of a near-field optical probe, and the near-field optical probe produces a photon-generated carrier on a surface of a semiconductor material under test through excitation. 2) The excited photon-generated carrier is concentrated on the surface of the semiconductor material, and recombination is conducted continuously with a surface state as a recombination center. 3) A change in a lattice constant is produced due to an electronic volume effect, a stress wave is produced, and a signal of the stress wave is detected in a high-frequency broadband ultrasonic testing mode. 4) Fitting calculation is conducted on the signal of the stress wave to obtain the lifetime of the surface state carrier ?c.