Abstract: The present application provides a player, a playing system, and a playing method. The player includes a main body, a control assembly, and an audio component, where the main body includes a light-transmitting element, a display screen with a reflection effect, and a display space, the display space being arranged between the display screen and the light-transmitting element. An object distance between the light-transmitting element and the display screen forms a front depth of field of an image, such that a viewer is given an impression that the image is displayed in a stereoscopic space; and the reflection of the display screen can effectively enhance the impression of the viewer that the stereoscopic image displayed by the display screen is stereoscopically displayed in the display space.

Abstract: A locomotive regenerative electric energy feedback system with an ice melting function, comprising two regenerative electric energy feedback devices (1). A direct-current side positive electrode of the regenerative electric energy feedback device (1) is connected to a positive electrode bus of a subway traction network, wherein the positive electrode bus is connected to an uplink contact network and a downlink contact network respectively via a first switching switch (4) and a second switching switch (5). A direct-current side negative electrode of the regenerative electric energy feedback device (1) is connected to the downlink contact network or the uplink contact network via a third switching switch (2), and the direct-current side negative electrode is connected to a negative electrode bus of the subway traction network via a fourth switching switch (3). Further disclosed is a control method corresponding to the system.

Abstract: A locomotive regenerative electric energy feedback system with an ice melting function, comprising two regenerative electric energy feedback devices (1). A direct-current side positive electrode of the regenerative electric energy feedback device (1) is connected to a positive electrode bus of a subway traction network, wherein the positive electrode bus is connected to an uplink contact network and a downlink contact network respectively via a first switching switch (4) and a second switching switch (5). A direct-current side negative electrode of the regenerative electric energy feedback device (1) is connected to the downlink contact network or the uplink contact network via a third switching switch (2), and the direct-current side negative electrode is connected to a negative electrode bus of the subway traction network via a fourth switching switch (3). Further disclosed is a control method corresponding to the system.

Abstract: A bismuth and magnesium co-doped lithium niobate crystal includes Li2CO3, Nb2O5, Bi2O3 and MgO, wherein the molar ratio of [Li] and [Nb] is 0.90-1.00, the molar percentage of Bi2O3 in the mixture is 0.25-0.80%, and the molar percentage of MgO in the mixture is 3.0-7.0%. The bismuth and magnesium co-doped lithium niobate crystal has enhanced photorefraction, improved photorefractive sensitivity, shortened holographic grating saturation writing time, and the photorefractive diffraction efficiency can reach up to 17%. The response time is only 170 ms, when the holographic storage experiment is carried out using 488 nm continuous laser. Therefore, this crystal can be used in the field of holographic imaging.

Abstract: A bismuth and magnesium co-doped lithium niobate crystal includes Li2CO3, Nb2O5, Bi2O3 and MgO, wherein the molar ratio of [Li] and [Nb] is 0.90-1.00, the molar percentage of Bi2O3 in the mixture is 0.25-0.80%, and the molar percentage of MgO in the mixture is 3.0-7.0%. The bismuth and magnesium co-doped lithium niobate crystal has enhanced photorefraction, improved photorefractive sensitivity, shortened holographic grating saturation writing time, and the photorefractive diffraction efficiency can reach up to 17%. The response time is only 170 ms, when the holographic storage experiment is carried out using 488 nm continuous laser. Therefore, this crystal can be used in the field of holographic imaging.