Abstract: A filler for vacuum brazing of TU1 oxygen-free copper is an Au—Cu—Ni filler including the following elemental compositions in a specified proportion: 69% to 90% of Au, 9% to 30% of Cu, and 1% to 5% of Ni. The filler has a melting temperature of 900° C. to 910° C. The filler for vacuum brazing of TU1 oxygen-free copper can be used for brazing X-ray tube anodes, thereby realizing effective vacuum brazing.

Abstract: An open microfocus X-ray source and a control method thereof are provided. The open microfocus X-ray source includes: an open X-ray tube, a high voltage power supply (HVPS) system, a vacuum system and a control system. The open X-ray tube includes a cathode system, a deflection system and a focusing system. The HVPS system is configured to provide an emission current I0, an accelerating high voltage U0 and a grid voltage UG for an electron beam. The vacuum system is configured to perform vacuumization. The control system is configured to control, according to a spot size of an electron beam for bombarding an anode target, the HVPS system to adjust the emission current I0, the accelerating high voltage U0, a deflection coil current IXY of the deflection system, and a focusing coil current IF of the focusing system, such that the spot size meets a preset requirement.

Abstract: A filler for vacuum brazing of TU1 oxygen-free copper is an Au—Cu—Ni filler including the following elemental compositions in a specified proportion: 69% to 90% of Au, 9% to 30% of Cu, and 1% to 5% of Ni. The filler has a melting temperature of 900° C. to 910° C. The filler for vacuum brazing of TU1 oxygen-free copper can be used for brazing X-ray tube anodes, thereby realizing effective vacuum brazing.

Abstract: Provided is an antenna system applied to a mobile terminal and including a back shell having a metal frame, a main board received in the back shell, an antenna unit provided between the back shell and the main board. The main board includes a front surface facing towards the antenna unit and a back surface arranged opposite to and spaced apart from the front surface. The mobile terminal includes a first metal ground layer and a first electrode plate provided on the front surface, a second metal ground layer and a second electrode plate provided on the back surface. The first electrode plate and the second electrode plate are spaced apart from the first and second metal ground layer, and connected to the antenna unit and the metal frame. The first and second electrode plates are arranged opposite to and spaced apart from each other to form a capacitor structure.

Abstract: An antenna module including a first antenna and a second antenna close to the first antenna. The second antenna includes an isolation circuit and a second tuning switch controlling an access state of the isolation circuit. The second tuning switch includes two modes. When the second tuning switch is in a first mode, the isolation circuit accesses to a feeding network of the second antenna. When the second tuning switch is in a second mode, the isolation circuit does not access to the feeding network of the second antenna. Isolation of the first antenna and the second antenna in a preset band in the first mode is superior to that in the second mode.

Abstract: An antenna system and a mobile terminal are provided. The antenna system includes a front frame rib connecting a system ground with a first short-axis frame, a slit provided on a first long-axis frame, a radio frequency front end area provided in system ground, and first and second frame-joint points each connecting radio frequency front end area with a metal frame. The first and second frame-joint points are located between front frame rib and slit. The radio frequency front end area includes a feeding point, a matching circuit, an impedance tuning circuit and a switching circuit. The impedance tuning circuit and the switching circuit are adjusted to switch an operating state of antenna system in such a manner that the antenna system operates in different frequency bands. The antenna system includes one operating state in which the antenna system operates in a frequency band ranging from 1710 MHz to 2700 MHz.

Abstract: An antenna module includes a first antenna and a second antenna. The first antenna forms multiple operating states. By switching the multiple operating states, the first antenna supports an LTE low frequency of 698-960 MHz and an LTE medium-high frequency of 1710-2690 MHz, and supports multi-carrier aggregation in the band. In each operating state, the first antenna also operates in 5G bands of 3300-3800 MHz and 4800-5000 MHz, the second antenna operates in 5G bands of 3300-3800 MHz and 4800-5000 MHz and a new TDD-LTE band of 5150-5925 MHz. The first antenna and the second antenna together form a 2×2 MIMO of 5G bands of 3300-3800 MHz and 4800-5000 MHz. The antenna module provided by the disclosure has better communication performance.

Abstract: An antenna system and a mobile terminal are provided. The antenna system includes a front frame rib connecting a system ground with a first short-axis frame, a slit provided on a first long-axis frame, a radio frequency front end area provided in system ground, and first and second frame-joint points each connecting radio frequency front end area with a metal frame. The first and second frame-joint points are located between front frame rib and slit. The radio frequency front end area includes a feeding point, a matching circuit, an impedance tuning circuit and a switching circuit. The impedance tuning circuit and the switching circuit are adjusted to switch an operating state of antenna system in such a manner that the antenna system operates in different frequency bands. The antenna system includes one operating state in which the antenna system operates in a frequency band ranging from 1710 MHz to 2700 MHz.

Abstract: An antenna module includes a first antenna and a second antenna. The first antenna forms multiple operating states. By switching the multiple operating states, the first antenna supports an LTE low frequency of 698-960 MHz and an LTE medium-high frequency of 1710-2690 MHz, and supports multi-carrier aggregation in the band. In each operating state, the first antenna also operates in 5G bands of 3300-3800 MHz and 4800-5000 MHz, the second antenna operates in 5G bands of 3300-3800 MHz and 4800-5000 MHz and a new TDD-LTE band of 5150-5925 MHz. The first antenna and the second antenna together form a 2×2 MIMO of 5G bands of 3300-3800 MHz and 4800-5000 MHz. The antenna module provided by the disclosure has better communication performance.

Abstract: An antenna module including a first antenna and a second antenna close to the first antenna. The second antenna includes an isolation circuit and a second tuning switch controlling an access state of the isolation circuit. The second tuning switch includes two modes. When the second tuning switch is in a first mode, the isolation circuit accesses to a feeding network of the second antenna. When the second tuning switch is in a second mode, the isolation circuit does not access to the feeding network of the second antenna. Isolation of the first antenna and the second antenna in a preset band in the first mode is superior to that in the second mode.

Abstract: Provided is an antenna system applied to a mobile terminal and including a back shell having a metal frame, a main board received in the back shell, an antenna unit provided between the back shell and the main board. The main board includes a front surface facing towards the antenna unit and a back surface arranged opposite to and spaced apart from the front surface. The mobile terminal includes a first metal ground layer and a first electrode plate provided on the front surface, a second metal ground layer and a second electrode plate provided on the back surface. The first electrode plate and the second electrode plate are spaced apart from the first and second metal ground layer, and connected to the antenna unit and the metal frame. The first and second electrode plates are arranged opposite to and spaced apart from each other to form a capacitor structure.

Abstract: The invention provides a compensation method for audio frame loss in a MDCT domain, the method comprising: when a frame currently lost is a Pth frame, obtaining a set of frequencies to be predicted, and for each frequency in the set, using phases and amplitudes of a plurality of frames before a (P?1)th frame in a MDCT-MDST domain to predict a phase and an amplitude of the Pth frame, and using the predicted phase and amplitude to obtain a MDCT coefficient of the Pth frame at each corresponding frequency; for a frequency outside the set, using MDCT coefficients of a plurality of frames before the Pth frame to calculate a MDCT coefficient value of the Pth frame at the frequency; performing an IMDCT for the MDCT coefficients of the Pth frame to obtain a time domain signal of the Pth frame.

Abstract: A hierarchical audio coding, decoding method and system are provided. The method includes dividing frequency domain coefficients of an audio signal after MDCT into a plurality of coding sub-bands, quantizing and coding amplitude envelope values of coding sub-bands; allocating bits to each coding sub-band of the core layer, quantizing and coding core layer frequency domain coefficients to obtain coded bits of core layer frequency domain coefficients; calculating the amplitude envelope value of each coding sub-band of the core layer residual signal; allocating bits to each coding sub-band of the extended layer, quantizing and coding the extended layer coding signal to obtain coded bits of the extended layer coding signal; multiplexing and packing amplitude value envelope coded bits of each coding sub-band composed by core layer and extended layer frequency domain coefficients, core layer frequency coefficients coded bits, and extended layer coding signal coded bits, then transmitting to the decoding end.

Abstract: A hierarchical audio coding, decoding method and system are provided. The method includes dividing frequency domain coefficients of an audio signal after MDCT into a plurality of coding sub-bands, quantizing and coding amplitude envelope values of coding sub-bands; allocating bits to each coding sub-band of the core layer, quantizing and coding core layer frequency domain coefficients to obtain coded bits of core layer frequency domain coefficients; calculating the amplitude envelope value of each coding sub-band of the core layer residual signal; allocating bits to each coding sub-band of the extended layer, quantizing and coding the extended layer coding signal to obtain coded bits of the extended layer coding signal; multiplexing and packing amplitude value envelope coded bits of each coding sub-band composed by core layer and extended layer frequency domain coefficients, core layer frequency coefficients coded bits, and extended layer coding signal coded bits, then transmitting to the decoding end.

Abstract: The invention provides a compensation method for audio frame loss in a MDCT domain, the method comprising: when a frame currently lost is a Pth frame, obtaining a set of frequencies to be predicted, and for each frequency in the set, using phases and amplitudes of a plurality of frames before a (P?1)th frame in a MDCT-MDST domain to predict a phase and an amplitude of the Pth frame, and using the predicted phase and amplitude to obtain a MDCT coefficient of the Pth frame at each corresponding frequency; for a frequency outside the set, using MDCT coefficients of a plurality of frames before the Pth frame to calculate a MDCT coefficient value of the Pth frame at the frequency; performing an IMDCT for the MDCT coefficients of the Pth frame to obtain a time domain signal of the Pth frame.