Abstract: The present disclosure provides a flexible microwave power transistor and a preparation method thereof. In view of great lattice mismatch and poor performance of a device prepared with a Si substrate in an existing preparation method, the preparation method of the present disclosure grows a gallium nitride high electron mobility transistor (GaN HEMT) layer on a rigid silicon carbide (SiC) substrate to avoid lattice mismatch between a silicon (Si) substrate and gallium nitride (GaN), improving performance of the flexible microwave power transistor. Moreover, in view of problems such as low output power, power added efficiency and power gain with the existing device preparation method, the present disclosure retains part of the rigid SiC substrate and grows a flexible substrates at room temperature to prepare a high-quality device. The present disclosure has greatly improved power output capability, efficiency and gain, and basically unchanged performance of device under 0.75% of stress.

Abstract: A low-complexity panoramic video coding method considering distortion temporal propagation is provided. By analyzing the inter-frame reference relationships under the random access coding structure and establishing the corresponding distortion propagation chain, the method utilizes distortion impact factors of coding units to adjust encoding parameters, thereby optimizing the encoding process. Furthermore, the method addresses the issue of oversampling arising from the varying geometric deformations in different latitude regions during the projection of spherical images in panoramic videos. This is achieved by adjusting coding parameters based on the ratio of area changes at different latitudes. The proposed approach significantly enhances coding performance.

Abstract: A multi-source domain adaptation model by aligning partial features includes a general feature extraction module, a feature selection module for partial feature extraction with the dedicated loss function, three partial feature alignment losses, and two classifiers for adversarial training, where the three partial feature alignment losses include an intra-class partial feature alignment loss, an inter-domain partial feature alignment loss, and an inter-class partial feature alignment loss. With the partial features extracted by the general feature extraction module and the feature selection module following three different partial feature alignment losses, the model is capable of clustering the samples from the identical categories and isolating samples from distinct classes.

Abstract: A new variable selective etching technology for thick SOI devices. An SOI material is etched by the following steps: (1) providing an SOI wafer; (2) depositing a composite hard mask with a variable selection ratio to replace a traditional hard mask with an invariable selection ratio; (3) applying a photoresist; (4) mask making, namely defining a to-be-etched region by using a photoetching plate; (5) etching the photoresist in the defined region; (6) etching the composite hard mask; (7) removing the photoresist; (8) etching top silicon by using a second etching method at a first selection ratio; and (9) etching a buried oxide layer by using a third etching method at a second selection ratio. The new variable selective etching technology avoids the damage to a side wall of a deep trench when the buried oxide layer is etched, and does not need to use an excessive thick hard mask.

Abstract: A high-dimensional non-orthogonal transmission method is provided. In the method, signals of various users are mapped to form high-dimensional signals, and the high-dimensional signals are pre-coded, such that non-orthogonal transmission is realized in a higher dimension. Moreover, different users perform matched receiving on respective signals, and non-orthogonal transmission signals can be recovered merely by means of a receiver with a linear complexity. By means of the method, multi-user data non-orthogonal transmission can be realized without depending on conditions such as user pairing and collaboration, and various users do not need to perform iterative feedback, such that the detection complexity of non-orthogonal multi-user signals is significantly reduced.

Abstract: A method for blockchain-based time stamping for digital signature is disclosed. The method includes two participants: a signer who signs a message, a verifier who verifies the message. In the method, the signer obtains hash values of a certain number of latest confirmed blocks in blockchain, binds these hash values and the message together to be a new message. The signer then generates a signature of the new message and inserts identification data of this signature and the new message into a transaction of blockchain. This method ensures that the generation time of the signature is prior to the generation time of the block which contains the signature and, at the same time, is after the generation time of the blocks whose hash values are included in the signature, which produces an accurate time interval for the digital signature.

Abstract: A spatial position-dependent I/Q domain modulation method, dual domain modulation method and multiple access communication method are provided. The methods eliminate the dependence of physical layer secure communication on channel state information, and realize the function that a receiver at an expected position can communicate normally, while an eavesdropper at other positions cannot receive a signal or can only receive a wrong signal. The security capability of a wireless communication system is improved from the spatial dimension. The multiple access communication method can realize the distinguishing of multiple users according to precise spatial position points. Even if a plurality of users are located in the same sector in an angular domain, as long as the spatial positions of these users are different, the method can be used to perform multiple access communication, thereby further improving the spatial multiplexing rate of the system and increasing the system capacity.

Abstract: A transparent top electrode composite film for organic optoelectronic devices includes a substrate, an MoOx film layer coated on the substrate, a doped Ag-based film layer coated on the MoOx film layer and an HfOx film layer coated on the doped Ag-based film layer. A preparation method of the transparent top electrode composite film, which is achieved under vacuum and low temperature, includes steps of (A) depositing an MoOx film layer on a substrate through thermal evaporation process or electron beam evaporation process without heating the substrate; (B) depositing a doped Ag-based film layer on the MoOx film layer through sputtering process or evaporation process; and (C) depositing an HfOx film layer on the doped Ag-based film layer through reactive sputtering process, thereby obtaining the transparent top electrode composite film. The composite film is able to be used as a top electrode material for organic optoelectronic devices.

Abstract: A system for real-time target identification of an unmanned aerial vehicle (UAV) based on an embedded technique and an improved YOLO4 algorithm, and relates to the field of real-time target detection is disclosed. The system for real-time target identification of a UAV based on an embedded technique and an improved YOLO4 algorithm abandons a conventional “one-to-one” mode, and can be used for a plurality of UAV data processing applications, and multiple users in different geographical locations can further remotely manage and control the system. Particularly, in a target identification client of the present disclosure, to obtain a better real-time identification effect, a YOLOv4 target identification algorithm is improved, so that a better identification result and a faster identification speed are obtained.

Abstract: A high-dimensional signal transmission method is provided. The method generates M M-dimensional first signals on the basis of M original signals and generates M M-dimensional second signals on the basis of a precoding signal and of the first signals, and finally, a transmitter sums all of the second signals and then transmits by utilizing M subchannels. As such, each subchannel carries information of the M original signals; hence, when any subchannel experiences deep fading, the deep fading is shared jointly by M signals, thus preventing the deep fading from causing a particularly severe impact on any signal. Moreover, all of the original signals can be recovered by utilizing the signals on the other subchannels, thus increasing the systematic resistance against subchannel deep fading. Meanwhile, the system implements the parallel transmission of the M original signals, thus ensuring the throughput of a communication system.

Abstract: A phase domain modulation method dependent on a spatial position is provided. The method mainly includes the following steps: a transmitter and a receiver perform time synchronization to obtain a synchronization time; the transmitter performs a phase domain precoding operation on an original signal to obtain a phase domain pre-coded signal; the receiver receives the phase domain pre-coded signal, obtains a phase domain initial reception signal, and performs a phase domain matching operation on the phase domain initial reception signal to obtain an estimation of the original signal.

Abstract: A homogenization field device with low specific on-resistance based on multidimensional coupled voltage dividing mechanism includes a first conductive type semiconductor substrate, a first conductive type well region, a first conductive type semiconductor contact region, a second conductive type drift region, a second conductive type well region, a second conductive type semiconductor contact region, a first dielectric oxide layer, a second dielectric oxide layer, a third dielectric oxide layer, a fourth dielectric oxide layer, a polycrystalline silicon electrode of a floating field plate, a polycrystalline silicon electrode of a control gate, a first layer of metal strips and a second layer of metal strips. The first dielectric oxide layer and the polycrystalline silicon electrode of the floating field plate form a vertical floating field plate, and the first layer of metal strips, the second layer of metal strips and the fourth dielectric oxide layer form a surface fixed dielectric capacitor.

Abstract: A Mg—Ta based dielectric ceramic for multi-layer ceramic capacitor (MLCC) and a low-temperature preparation method thereof are provided. By providing a glass additive with high matching with a Mg—Ta ceramic, a modifier A+12CO3—B2+O—C3+2O3—SiO2 (A=Li, K; B=MnO, CuO, BaO; C=B, Al) is intruded in to a main material MgO—Ta2O5, which can significantly reduce the sintering temperature and provide a negative temperature coefficient of dielectric constant of ?100±30 ppm/° C., and reduce the deterioration factors of loss caused by an additive for sintering, and prepare a dielectric material applied to RF MLCC with low loss, low cost and good process stability.

Abstract: An SOI lateral homogenization field high voltage power semiconductor device, and a manufacturing method and application thereof are provided. The device includes a type I conductive semiconductor substrate, a type II conductive drift region, a type I field clamped layer, type I and type II conductive well regions, the first dielectric oxide layer forming a field oxide layer, the second dielectric oxide layer forming a gate oxide layer, a type II conductive buried dielectric layer, a type II conductive source heavily doped region, a type II conductive drain heavily doped region. The first dielectric oxide layer and the floating field plate polysilicon electrodes form a vertical floating field plate distributed throughout the type II conductive drift region to form a vertical floating equipotential field plate array. When the device is in on-state, high doping concentration can be realized by the full-region depletion effect form the vertical field plate arrays.

Abstract: A random phase modulation method depending on a communication distance is provided. In the method, time synchronization is carried out by means of a transmitter and a receiver, a local random signal is generated, and an original signal to be sent is pre-coded according to a transmission delay and the generated local random signal, such that random phase modulation depending on a communication distance is realized, potential security brought about by positions of the transmitter and the receiver is fully utilized, a receiver at an expected distance position can receive a signal with a correct phase, and a receiver at another distance position receives a signal with a scrambled phase, thereby improving the secure communication capability of a wireless communication system in terms of the dimension of space.

Abstract: A high-dimensional signal transmission method is provided. The method generates M M-dimensional first signals on the basis of M original signals and generates M M-dimensional second signals on the basis of a precoding signal and of the first signals, and finally, a transmitter sums all of the second signals and then transmits by utilizing M subchannels. As such, each subchannel carries information of the M original signals; hence, when any subchannel experiences deep fading, the deep fading is shared jointly by M signals, thus preventing the deep fading from causing a particularly severe impact on any signal. Moreover, all of the original signals can be recovered by utilizing the signals on the other subchannels, thus increasing the systematic resistance against subchannel deep fading. Meanwhile, the system implements the parallel transmission of the M original signals, thus ensuring the throughput of a communication system.

Abstract: A circuit and method for simulating real-time reconfigurable general-purpose memristor, nonlinear m-order polynomial fitting of mathematical model of a memristor is performed by using McLaughlin formula. m is related to the amplitude and frequency of an input signal and the fitting accuracy, thus the mathematical model of a memristor can be easily and quickly adapted by updating the polynomial order, the polynomial coefficients and the FPGA system clock cycle. Based on the FPGA, a system state variable generation module, a FIFO, a output module are used to obtain an output signal y[n]. the detailed steps of signal processing and displaying are given to obtain a display of a pinched hysteresis loop and a waveform display of time-domain. Simulation of high frequency memristor by setting polynomial coefficients can be obtained. Meanwhile, this is built based on FPGA, adopt digital circuit to simulates a reconfigurable general-purpose memristor, and experimental accuracy is enhanced.

Abstract: The invention belongs to the field of electronic ceramics and its manufacturing, in particular to the modified NiO—Ta2O5-based microwave dielectric ceramic material sintered at low temperature and its preparation method. It is guided by ion doping modification, not only considering the substitution of ions with similar radius, such as Zn2+ replacing Ni2+ ions, V5+ replacing Ta5+ ions; Meanwhile, the selected doped oxide still has the property of low melting point. Therefore, the microwave dielectric properties of NiO—Ta2O5-based ceramic material can be improved and the appropriate sintering temperature can be reduced. In the invention, by adjusting the molar content of each raw material, the NiO—Ta2O5-based ceramic material with low-temperature sintering, stable temperature and excellent microwave dielectric property is directly synthesized at one time, which can be widely applied to the technical field of LTCC.

Abstract: A hierarchical proxy deployment method includes: performing information collection and information interaction in a hierarchical proxy deployment architecture to obtain bandwidths and latencies of all inter-node communication links; and selecting an optimal proxy deployment solution from all feasible proxy deployment solutions based on the bandwidths and latencies of all the inter-node communication links. According to the method, a hierarchical proxy deployment architecture is used. An optimal proxy deployment solution is formed by selecting the optimal location and the optimal number of proxies for deployment to meet the transmission performance requirement of network applications in 5G/B5G networks. Therefore, transmission performance requirements are satisfied by a proxy deployment with a minimized number of proxies, thereby reducing network overheads and resource waste.

Abstract: A low-temperature sintered microwave dielectric ceramic material and a preparation method thereof are provided. The ceramic material includes a base material and a low-melting-point glass material; a general chemical formula of the base material is (Zn0.9Cu0.1)0.15Nb0.3(Ti0.9Zr0.1)0.55O2; a percent by weight of the low-melting-point glass material is in a range of 1 wt. % to 2 wt. %; chemical compositions of the low-melting-point glass material include A2CO3-M2O3—SiO2, A of which includes at least two of a lithium ion, a sodium ion, and a potassium ion, M of which includes at least one of a boron ion and a bismuth ion; and a sintering temperature of the ceramic material is in a range of 850° C. to 900° C. The microwave dielectric ceramic material has the advantages of low dielectric loss, simple and controllable process, etc., has good process stability, and can meet requirements for radio communication industry.