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This letter presents a Ka-band multilayer beaming-scanning antenna based on the electronically controlled liquid crystals (LC) phase shifter and proposes a new integrated and miniaturized LC antenna structure for the first time. The antenna is composed of four planar magnetoelectric dipole antenna units, four LC-based reflective phase shifters, and the power divider network, including the bias loading and DC blocking circuits. An external four-channel adjustable power module is designed with the field-programmable gate array (FPGA) to output the independent control and continuous adjustment of bias voltage to adjust the phase. The antenna operates at the frequency of 35 GHz and has an overall size of 35 mm50 mm2.5 mm. Measured results show that by adjusting each phase of the LC-based phase shifter through the power module, the structural and functional composite array achieves the one-dimensional scanning angle from -22 to +23 and the main lobe gain of 6.7 dBi.

This paper demonstrates an ultra-high frequency (UHF) liquid-metal monopole antenna qualified for reconfiguring its resonant frequency by stretching or shortening its length on a two-dimensional (2D) surface. The proposed antenna consists of liquid eutectic gallium and indium (EGaIn) and NaOH solution. A power supply generates a direct current (DC) potential between the EGaIn and NaOH solution. Depending on the electrically-driven method to push or withdraw the EGaIn, the antenna is capable of forming different lengths to redistribute the current of radiating element. Compared with the microchannel liquid-metal antenna, the proposed antenna can be tuned the length on a 2D surface, rather than relying on the microchannel for shaping. By varying the length of EGaIn on a 2D surface, the proposed antenna can provide continuously tunable frequency range and repeatability. For EGaIn monopole antenna with lengths from 50 mm to 10 mm, the measured resonant frequency operates from 0.78 GHz to 2.42 GHz for a tuning ratio 3.1: 1. The application of the design, operation of tuning liquid-metal antenna at several frequencies, and measurement process are explained in this paper.

Alternative unsplit-field-based absorbing boundary condition (ABC) computation approach for the finite-difference time-domain (FDTD) is efficiently proposed based upon the deep differentiable forest (DDF) model which is introduced to replace the conventional perfectly matched layer (PML) ABC during the computation process of FDTD. The field component data on the interface of traditional PML are adopted to train the DDF-based model for implementing the perfectly matched monolayer (PMM). The DDF has the advantages of both trees and neural networks. Its tree structure is easy to use and explain for the numerical PML data. Meanwhile, it has full differentiability like neural networks. The DDF can be trained by powerful deep learning techniques. Numerical cases have been carried out to benchmark the performance of the proposed method. Results illustrate that the DDF-based PMM could not only replace the traditional PML but be integrated into FDTD computation process with satisfactory numerical accuracy.

This article presents a microwave sensor composed of a cylindrical cavity resonator and thin plastic liquid container for noncontactual detection of the liquid solution concentration. The resonant frequency is tuned to around 11 GHz, resulting in miniaturized dimensions and easy integration with a wireless sensor system. The sensor is with a small volume of 21 cm3 and sensitivity of 0.4 kHz/(mg/L). Simulated results show a good linear relationship between the concentration of the sample solution and resonant frequency shift with the high sensitivity, which is consistent with the experimental result. Compared with other designs, the sensor also has a simple structure, low cost and easy implementation to in-situ and in-vitro detection scenarios.

Since the CDIO engineering education model was introduced to China in 2005, it has had a profound impact on Chinese engineering education in recent years. The concept of CDIO has inspired the teaching reform in Electronics and Information Engineering major. This article starts with analysis of the status of Electronics and Information Engineering major and divides its teaching system into three levels based on CDIO. Afterwards, this article describes the systematic architecture of course projects based on CDIO. Finally, suggestions for the teaching reform of Electronics and Information Engineering education based on CDIO mode is proposed.

This letter presents a high-efficiency circular-polarized (CP) rectenna at 5.8 GHz within wide input power range featuring low profile and radar cross section (RCS) reduction. Originating from the connection to a branch-line coupler, two identical subrectifiers in parallel combination are capable of extending the input power range and enabling the stability of dc output. The contribution of this combination in the performance of rectenna is experimentally demonstrated and a solution to RCS reduction by means of defected ground structure and complementary split-ring resonators is devised. The measured results show that the rectenna achieves a conversion efficiency of more than $60\%$ within the input power range from 2.2 to 17.6 dBm, and an in-band RCS reduction of 5.1 dB, verifying the applicability of wireless power transfer for CubeSats.

This letter presents a high-efficiency rectifier based on a miniaturized branch-line hybrid coupler (MBLHC), which can be applied to wireless power harvesting (WPH) featuring a wide input power range. Originating from the connection to the MBLHC, two identical subrectifiers are used to achieve less sensitivity to the impedance mismatching, and thus the input power range is extended. For validation, theoretical analysis is carried out and a rectifier working at 5.8 GHz is configured out. The measured results show that the rectifier can achieve a conversion efficiency of more than 60% within the input power range from 2 to 17.5 dBm, and a maximum efficiency of 81% with a more compact size.

Incorporating a truncation of the complex-frequency-shifted perfectly matched layer (CFS-PML), the direct-splitting- based Crank-Nicolson finite-difference time-domain (CNDS-FDTD) is developed and applied to the infrared two-dimensional layered material (2DLM) black phosphorous (BP) metasurface implementations on the all-dielectric nanostructure. To improve extremely low efficiencies in solving infrared terahertz (THz) problems with the few-atomic-layer thickness of 2DLMs, the CFS-CNDS-FDTD is proposed in demand due to the fact that it possesses capabilities of implicit FDTD method and unsplit-field CFS-PML truncation, respectively, in completely conquering the Courant-Friedrich-Levy condition (CFL) limit and holding good performance. The temporal incremental in the CFS-CNDS-FDTD can reach 1000 times larger than that in the regular FDTD for infrared nanoscale problems centered at the 2.5 THz and then keep accurate. Three-dimensional (3D) numerical cases have been carried out to corroborate the proposed method. The CFS-CNDS- FDTD can not only achieve high accuracies and then saves several dozen times of CPU time as compared to the regular FDTD, but also pave the way for designing all-dielectric nanostructures with other 2DLM metasurfaces.

Sensors are key components in structural health monitoring. Although significant improvements have been made on monitoring technologies by using many advanced smart sensors, the need of cables and power supplies still causes much inconvenience in the practical implementation of these technologies. In this paper, we propose a novel rectangular patch antenna to monitor the structural health in a wireless and passive manner so that the drawback of traditional monitoring methods can be fully overcome. The antenna is used as a sensor and its resonant frequency will change linearly in terms of its size changes in both horizontal and vertical directions. The antenna will transmit an electromagnetic wave with the resonant frequency information to a reader by a long distance and activate the chip in the reader. According to the received information about the resonant frequency, the change of the targeted structure's strain can be measured in real time and its health state can then be evaluated. Simulations and experiments show that the designed antenna is an excellent strain sensor and can be applied to the health detection for many types of structure.

Vector reflection coefficient is very important for an antenna. Traditionally, VNA (vector network analyzer) is used as the measuring tool. In this paper, we put forward a SDR based measuring method for S parameter detection of antennas. LabVIEW is used to build a framework of this platform. Users can adjust the specific parameters of the signal generated and processed by USRP according to the actual scenario. This method tends to be more flexible and efficient. A comparison of different measuring method is also made to prove its reliability.

Certain chemotherapeutics (e.g., oxaliplatin, OXA) can evoke effective antitumor immunity responses by inducing immunogenic cell death (ICD). Unfortunately, tumors always develop multiple immunosuppressive mechanisms, such as the upregulation of immunosuppressive factors, to counteract the effects of immunogenic chemotherapy. Indoleamine 2,3-dioxygenase-1 (IDO1), a tryptophan catabolic enzyme overexpressed in tumor-draining lymph nodes (TDLNs) and tumor tissues, plays a pivotal role in the generation of the immunosuppressive microenvironment. Reversing IDO1-mediated immunosuppression may strengthen the ICD-induced immune response. Herein, we developed a nanoenabled approach for IDO1 pathway interference, which is accomplished by delivering IDO1 siRNA to both TDLNs and tumor tissues with the help of cationic lipid-assisted nanoparticles (CLANs). We demonstrated that the contemporaneous administration of OXA and CLANsiIDO1 could achieve synergetic antitumor effects via promoting dendritic cell maturation, increasing tumor-infiltrating T lymphocytes and decreasing the number of regulatory T cells in a subcutaneous colorectal tumor model. We further proved that this therapeutic strategy is applicable for the treatment of orthotopic pancreatic tumors and offers a strong immunological memory effect, which can provide protection against tumor rechallenge.

Emerging research revealed that the view-type of photos is not only related to the field of data sciences, such as the sentiment brought forth by sightseeing spots, but also in the field of social sciences about human emotions and behaviors. These potential usages of view-types trigger a challenging problem, that is to automatically distinguish them into wide or narrow. In this paper, we present a computational model to classify them inspired by the human visual system. We found two cues that can represent the visual attention, i.e., focus cue and scale cue. The focus cue is modeled in the frequency domain using the non-sampled contourlet transform (NSCT) and speeded up robust features (SURF). The scale cue is modeled by defining the spatial size and conceptual sizes of an object in the image, whereby AdobeBING and convolutional neural network are used for the respective measurements. By integrating these focus and scale models, a robust scheme is hence proposed for this non-trivial task. The experiments on a newly established dataset, which has 5050 natural images, show better performance by our proposal when compared to the state-of-the-arts.

A novel a monopole dual frequency MIMO antenna is proposed. The antenna adopts different length of double branch structure, the radiator is broken line processing, the surface current length is increased. In order to improve the isolation of the antenna, the defected ground structure is used and the two radiation elements are symmetrically treated at the same time. The overall size of the antenna is 42 mm 39.7 mm, which is compact and easy to process and integrate. The two frequency points of the antenna are 2.4 GHz and 5.2 GHz, which can be used in WLAN communication. The design structure of the antenna and the influence of different parameters on the performance of the antenna are given.

Multi-band antenna and dielectric resonator antenna (DRA) have been playing an important role in the antenna field. In this paper, a triple-band DRA using microstrip line feeding is proposed. The proposed antenna is mainly composed of two cut cylindrical dielectric resonator and FR-4 substrate. By reasonably distributing the position and length of the microstrip feeding line, the antenna proposed in this paper can work in three working bands successfully. Three operating bands with the central frequencies of 6.52 GHz (6.11−6.72 GHz), 7.91 GHz (7.68−8.27 GHz), and 9.54 GHz (9.04−9.72 GHz) have been achieved, respectively. Simulation results show that the antenna also has a good performance in gain and it can be very useful in WLAN applications.

A flash analog-to-digital converter (ADC) with 6-bit and 10 GS/s is proposed for 28-nm CMOS process. The proposed continued pipelined clock triggers the dynamic amplifier and two-stage comparator to improve the conversion speed of the ADC. Moreover, a non-binary flash conversion architecture is designed, which utilizes the edge comparators to increase the effective number of bits. The bubble and meta-stability issues are both addressed by logic gates. The measured SNDR and SFDR were 37.53 dB and 43.22 dB, respectively, with a 0.46-GHz input at 10 GS/s operation while consuming 32.6 mW of total power. At 10 GS/s, the ADC consumes 32.6 mW from a 1.0-V supply voltage in 28-nm CMOS process and achieves a Schreier figure of merit of 146 dB.

A frequency-reconfigurable multifunctional microstrip patch antenna based on liquid metal is proposed in this paper. This antenna consists of a microstrip patch which is formed by eutectic gallium indium (EGaIn), a kind of liquid metal with σ = 3.4 × 106 S/m, in a microfluidic channel on a PMDS substrate. The continuous frequency tuning is achieved by adjusting the amount of liquid metal in the microfluidic channel in order to change the length of the patch. The proposed antenna has two working states: dual-band mode and multi-band mode, which are achieved by adding or subtracting the number of parasitic components. The design is simulated in HFSS. The corresponding resonate frequency range in dual-band mode can cover 5.60 GHz to 6.06 GHz and 6.76 GHz to 8.34 GHz, and in multi-band mode, the antenna have three or four resonate frequencies which can cover the range from 5.34 GHz to 8.10 GHz.

In this paper, a dual-band slot antenna is proposed. The dual-band slot antenna has a novel structure and a small size. The antenna is made of two 0.4-mm thick conducting plates with a compact size of 15 mm 40 mm and relative dielectric constant of 4.4, and the probe feeder and shorting pins are made of three 6-mm long conductors between the two substrates. This dual-band slot antenna is designed and simulated by the high frequency structure simulator (HFSS) software. In order to get the specific size of the antenna, the key parameters are simulated, analyzed and optimized. The results show that the antenna has two frequency bands of 3.1 GHz and 4.6 GHz. These two frequency bands can be used in WLAN/WiMAX communications. In addition, the antenna has a very good performance in other aspects like bandwidth.

A circular polarized frequency reconfigurable antenna with self-complementary metasurface is proposed in this paper. A novel θ shaped self-complementary metasurface has been proposed and is attached to the substrate to realize frequency reconfiguration. By rotating the unit cell of the metasurface, the resonant frequency of the proposed antenna can be tuned from 37.0 GHz to 41.0 GHz. And the proposed antenna has realized the circular polarization near the resonant frequency. The proposed antenna has good performance in 5G New Radio spectrum.

With the continuous improvement of people’s safety awareness, infrared products as human motion detection technology have been widely used in the field of security. In order to better apply infrared products to life, improving the performance of infrared products and reducing the cost of products has become the main goal. According to the signal collected by Pyroelectric infrared (PIR) sensor, this paper establishes a database model. According to the data collected, Kalman filter is used to preprocess the data. The validity of the data after preprocessing is judged by the algorithm. The experimental results show that the accuracy of the model can reach 97% by using a support vector machine (SVM) algorithm incorporated with Fast Fourier Transform (FFT). According to the above algorithm flow, a real-time intellectual property (IP) core is designed by using hardware description language, after establishing the data processing algorithm. The interface design, timing design and function design of the IP core are designed. The IP core can be connected to the microcontroller unit (MCU) as an independent peripheral to form a PIR special processor, which can detect the distance of 15 m in real time.

This paper presents a new structure of the subsampling phase detector (SSPD) and charge pump in Subsampling phase locked loop (PLL). In contrast with traditional Subsampling phase locked loop (SSPLL), it has no frequency- locked loop (FLL), but has a larger frequency acquisition range. It combines SSPD with a conventional phase frequency detector/charge pump (PFD/CP) to ensure a wide operating range. A range detector is designed to distinguish the big and small phase error. When the phase error is small, the charge pump is controlled by the sampling voltage (Vsam), otherwise controlled by the output of the phase detector (PD) and charge pump (CP).

In this paper, a simulation method reproducing the impact of multiple absorbing knife-edge diffraction on wireless radio propagation channel is proposed based on propagation graph modeling (PGM) that is recently applied to channel simulation with low-complexity by utilizing matrix product to update channel transfer states. In the new PGM proposed here, an iterative mathematic transformation is derived and applied to adapt the distance addition defined in the diffraction to a recursive matrix multiplication. Simulation results are compared among the newly proposed method and other classical numerical analytical approaches, e.g. geometry theory diffraction (GTD) and Deygout methods. It can be observed that the proposed method performs in good consistency to the existing methods when being applied to simulate the path loss behaviors.

In this paper, a broadband ±45° dual-polarized arrow-shaped crossed-dipole antenna is proposed and it can be applied to the base stations. Each dipole is fed by a coaxial cable and one half of each dipole is above the substrate while the other half is below it. The antenna has a good impedance matching at two resonant frequencies with a return loss of more than 20 dB and 40 dB. The maximum gain of the antenna is more than 6 dB. The antenna has a bandwidth of 70% at the frequency range 2.3−4.5 GHz and has a mutual coupling of less than −30 dB. Moreover, the size of the double-polarized dipole antenna is just 22.11 mm ×22.11 mm.

With the development of the fifth generation (5G) and the Internet of Things (IoT), wireless charging is driving people’s life. The technology of rectifier is considered to be count. However, the conversion efficiency usually get a peak value at a narrow range of input power, which is not cost-effective. In this paper, a high efficiency rectifier with widening input power range is proposed. The results show that the power range can be widen from 8 to 15 dBm over the efficiency of 60%, of which the peak efficiency is over 72%.

with the rapid development of artificial intelligence (AI), machine learning technology also has the ability to perform online operations. Since electromagnetic waves are greatly affected by environmental factors during the propagation process, it is easy to generate complex scattering and diffraction during the propagation process. The existing wireless propagation models need to be further corrected by using a large amount of collected engineering data in practical applications, so a wireless propagation model based on machine learning need to be built, and the problem of the rational deployment of base stations can be solved. In order to obtain the propagation model that accords with the actual environment of the target region, this paper collects a large amount of additional measured data, engineering parameters and electronic maps to correct the propagation model after learning which is based on the traditional wireless propagation model function fitting process under the condition that the engineering parameters, geographical location information, and RSRP (average signal receiving power) of a specific geographical location measurement point are known. After appropriate features are be designed, the feature set will be performed by using divergent analysis, neural network connection fitting and principal component analysis. Then the effective eigenvalues are selected and input into the BiLSTM-based wireless propagation model. BiLSTM is used to characterize the relationship between features and the relationship between the characteristics and the target value RSRP. The BiLSTM representation relationship will be output through a layer of fully connected output. After continuous training and tuning, the RSRP of different geographical locations is predicted.

By changing the excitation phase of each antenna element, the influence of the excitation phase on planar antenna array of magneto-electric dipole antenna is studied. The 2×3 planar antenna array is composed of six magneto-electric dipole antennas. The distance between each antenna element is 1.25 mm. With different excitation phases of antenna elements, the planar antenna array has different gain and radiation pattern while the reflection coefficient is identical. When the array elements are excited by the same phase at the same time, the planar antenna array achieves a wide operating bandwidth of 53.7% covering 45.0 GHz to 78.0 GHz. And it achieves a high gain of 17.8 dBi in the direction of maximum radiation. The proposed planar antenna array can be well used in millimeter wave band.

In this paper, a wideband antenna for fifth generation (5G) wireless communication application is proposed. The antenna is designed on a FR4 substrate whose size is $6\ \mathbf{mm} \times 4\ \mathbf{mm}\times 0.5\ \mathbf{mm}$ and is composed of sector patch arms, a microstrip gradient balun line, a microstrip transmission line, and a substrate layer. The parameters are adjusted and optimized according to the simulation results. By adjusting their shapes and sizes, the operating frequency range of the proposed antenna is from 26.32 GHz to 37.30 GHz, which is within the working frequency band of 5G wireless communication. Also, the antenna has a resonant frequency at 28 GHz with a high efficiency of 86.39% and its realized gain is up to 4.92 dBi. This antenna has the advantages of small size, high gain, high efficiency, and wide frequency band, and is very suitable for 5G wireless communication.

A low-profile crossed-dipole antenna with a hybrid Electromagnetic Bandgap (EBG) reflector is proposed in this paper. The crossed dipoles are etched on a Rogers RO4350 substrate above a hybrid EBG reflector etched on a FR4 substrate. By using the leaky wave region, the bandwidth of the EBG reflector is expanded, without increasing its thickness. The bandwidth of our antenna reaches 37.6%, and the total thickness of our antenna is only 6.16 mm. After introducing the hybrid EBG reflector, the maximum axial gain is increased to 11.98 dH $\mathbf{i}$ , compared to the uniform EBG reflector's 7.18 dBi.

A novel reconfigurable dual band liquid metal antenna on a 2D surface is proposed in this paper. The structure of the proposed antenna comprises a pair of symmetrical T-stubs and an inverted T-stub on a 3D printed substrate. Depending on the fluidity of the liquid eutectic gallium and indium (EGaIn), the proposed antenna allows liquid metal to move on a 2D surface. An electrochemical method generates a DC loop between EGaIn and NaOH solution that is used to transfer a DC signal to the surface of EGaIn. By inducing a changing in the length of EGaIn, this liquid metal antenna offers an ability to accomplish the reconfigurable frequency properties with dual band. The advantages of liquid metal antenna on a 2D surface lie in the continuous tunable frequency band and complicate conductor topology. The propose antenna can accomplish four tunable states with dual band. The first band of frequency reconfigurable range is from 1.06 GHz to 1.18 GHz and the second band is from 2.24 GHz to 2.99 GHz.

With the development of radar technology, reduction of radar cross section (RCS) is becoming more and more important in the electromagnetic field. Microwave absorber is one of main methods to reduce radar cross section. In this work, we propose a novel design of microwave absorber with resistive screen. The equivalent circuit method is implemented in the design and we adjust values of $L$ and $C$ to get a better result. In addition, it has the good performance with total thickness is $0.25\lambda$ and it covers the frequency range from 3.4 GHz to 15.85 GHz. Furthermore, the reflection peak reaches −18.2 dB at 14.2 GHz. Finally, we draw a conclusion that the microwave absorber that we proposed is better design.

For microwave power transmission technology, improving the efficiency of rectifier can always be the crux of the matter. However, the performance of conventional rectifiers are highly dependent on the input power, and the external structures added together are not convenient for integration. Therefore, in this paper, a miniaturized high efficiency rectifier with wide input power range is proposed. According to the results, over 50% of the efficiency is obtained in a wide range (24.5 dBm and 21.8 dBm for simulated and measured results respectively), where the peak efficiency are 82% and 77% respectively.

Ahstract-A dualband rectangular dielectric resonator antenna (DRA) with a circular patch over a metasurface for achieving circularly polarized radiation is proposed. The proposed antenna is comprised of a substrate with ground plane, a rectangular dielectric resonator (DR), a metasurface, a circle patch, and a coaxial probe. The metasurface upon the substrate can realize the circular polarization. The circle patch upon the rectangular DR can increase the reflection coefficient and realize the dual-band working mode. Simulation results show that the proposed DRA has a dual band of operating frequency which is 24.7% (4.23 GHz - 5.42 GHz) and 8.5% (5.60 GHz - 6.10 GHz), respectively. Also, the antenna has a circular polarization in the frequency range 5.60 GHz - 6.10 GHz and it could be widely used for 5G wireless communication. The antenna proposed in this paper has achieved dualband and circular polarization of dielectric resonator antenna simultaneously.

By linear arrangement of four magneto-electric dipole antennas, a high gain magneto-electric dipole antenna linear array with wide bandwidth is presented, especially for the new unlicensed frequency band. Through the reasonable arrangement of multiple antennas, the gain of the antenna array is significantly improved. The proposed antenna has low profile to be easily integrated. The proposed antenna achieves a simulated impedance bandwidth of 53.8% covering 44.4 GHz to 77.1 GHz. It includes the new unlicensed frequency band (57 – 71 GHz) totally. The maximum gain in the Z-direction is up to 16.01 dBi. The proposed antenna has the advantages of high gain, wide bandwidth and low profile.

This paper introduces a reconfigurable Yagi-Uda antenna using liquid metal eutechtic gallium and indium (EGaIn). The antenna consists of three coaxial circular capillaries inserted with electrolyte and certain amount of liquid metal according to their different functions. Arbitrary intended directions in 2D-plane can be realized by changing the position of EGaIn in each capillary electrochemically. The resonant frequency is also adjustable by altering the location of the feed element. The results of HFSS simulation show that the antenna has resonant frequencies of 1.69 GHz and 2.03 GHz with high gain in the intended directions.

Radio frequency identification (RFID) technique is a kind of wireless automatic identification technology. This technique has several advantages, i.e., long reading distance and large information storage. We propose a Chipless RFID tag using surface acoustic wave (SAW) to read and store the information. The tag features small size, high flexibility, strong radiation resistance, high consistency, repeatability, as well as high temperature stability. The simulation results by COMSOL verify the good performance of the tag antenna.

Nowadays, radar cross section (RCS) reduction is becoming more and more important in the military and civilian fields. In the work, we put forward a novel method to reduce RCS of the object by using the microwave absorber. The bandwidth of our absorber design reaches 14.63 GHz, from 3.37 GHz to 18 GHz. Additionally, the minimum reflection loss is −14.42 dB at 5.14 GHz and the total thickness is 3 mm. When our design is put on a PEC cylinder, it also has a good performance both for horizontally illumination and vertically polarized illumination. In a word, our absorber design is an effective way to achieve RCS reduction.

Partially defective fingerprint image (PDFI) with poor performance poses challenges to the automated fingerprint identification system (AFIS). To improve the quality and the performance rate of PDFI, it is essential to use accurate segmentation. Currently, most fingerprint image segmentations use methods with ridge orientation, ridge frequency, coherence, variance, local gradient, etc. This paper proposes a method of XFinger-Net for segmenting PDFIs. Based on U-Net, XFinger-Net inherits its characteristics. The attention gate with fewer parameters is used to replace the cascaded network, which can suppress uncorrelated regions of PDFIs. Moreover, the XFinger-Net implements a pixel-level segmentation and takes non-blocking fingerprint images as an input to preserve the global characteristics of PDFIs. The XFinger-Net can achieve a very good segmentation effect as demonstrated in the self-made fingerprint segmentation test.

Highlights • Low prealbumin concentration was associated with increased risk of worse outcomes (all-cause death, ICU admission and mechanical ventilation) in elderly COVID-19 patients. • There was a negative linear trend correlation between serum prealbumin concentration and risk of worse outcomes in elderly patients with COVID-19 infection. • A low prealbumin concentration can be regarded as a signal identifying the at-risk elderly patient who would suffer worse outcomes and requires careful assessment and monitoring., Objective: Severe patients tended to have lower serum prealbumin concentration in patients with novel coronavirus (SARS-CoV-2) infected pneumonia (COVID-19). This study was performed to investigate the association of prealbumin at baseline on COVID19-related mortality in elderly patients. Methods: We non-selectively and consecutively collected participants in Tongji Hospital in Wuhan from January 17 to February 17, 2020. Univariate and multivariate logistic regression models were employed to evaluate the correlation between prealbumin and in-hospital outcomes (in-hospital mortality, ICU admission and mechanical ventilation) in elderly COVID-19 patients. Linear trend was performed by entering the median value of each category of prealbumin tertile as continuous variable and was visually confirmed by using generalized additive models. Interaction and stratified analyses were conducted as well. Results: A total of 446 COVID-19 elderly patients were included in the final analyses and the in-hospital mortality was 14.79%. 15.47% patients admitted to intensive care unit and 21.3% patients required mechanical ventilation. Compared with patients in the highest tertile, the prealbumin of patients in the lowest tertile had a 19.09-fold higher risk of death (OR = 20.09; 95% CI, 3.62 to 111.64; P = 0.0006), 25.39-fold higher risk of ICU admission (OR = 26.39; 95% CI, 4.04to 172.39; P = 0.0006) and 1.8-fold higher risk of mechanical ventilation (OR = 2.8; 95% CI, 1.15 to 6.78; P = 0.0227) after adjustment for potential confounders. There was a linear trend correlation between serum prealbumin concentration and risk of in-hospital mortality, ICU admission and mechanical ventilation in elderly patients with COVID-19 infection. Conclusion: Prealbumin is an independent risk factor of the in-hospital mortality for COVID-19 elderly patients. Assessment of prealbumin may help identify high risk elderly individuals with COVID-19.

In this paper, a loop-bowtie strap feed antenna with $\lambda /4$ meandered dipoles and modified T-matching networks is proposed. T-matching networks are employed to guide current, enhancing gain of the antenna. Aiming to improve robustness of the antenna used both on metallic objects and in air, two steps are implemented, respectively. Noticeably, the method is universal to design antimetal tag which also has a good performance in air. Four movable connection stubs and H-slots together raise degrees of freedom to tune global RFID frequency band. Besides, a simple equivalent circuit is presented, giving a convenient design rule and reasonable analysis of the design. Finally, reflection coefficients are measured using two methods, one is using the calibration kit made by us and the other is using port extension. Reading distances in different cases are also measured, showing the maximum distances are 1.8 and 2.7 m on metallic objects and in air, respectively. Measured and simulated results are with a good agreement, verifying the rationality of the design.

This paper presents a fast discrete Curvelet transform (FDCT)-based technique for multi-focus image fusion to address two problems: texture selection in FDCT domain and block effect in spatial-based fusion. First, we present a frequency-based model by performing FDCT on the input images. Considering the human visual system characteristics, a union of pulse coupled neural network and sum-modified-Laplacian algorithms are proposed to extract the detailed information of frequencies. Then, we construct a hybrid spatial-based model. Unlike other spatial-based methods, we combine the image difference and the detailed information extracted from input images to detect the focused region. Finally, to evaluate the robustness of proposed method, we design a completed evaluation process considering the misregistration, noise error, and conditional focus situations. Experimental results indicate that the proposed method improves the fusion performance and has less computational complexity compared with various exiting frequency-based and spatial-based fusion methods.

Since remote cerebellar hemorrhage, with intracerebral hemorrhage after supratentorial neurosurgery, is rare, its pathophysiology remains elusive.Here, we report a 64-year-old man who had severe bilateral symmetric remote cerebellar hemorrhage with frontal lobe hemorrhage following burr-hole evacuation for supratentorial chronic subdural hematoma.Computed tomography venography showed undeveloped left internal jugular vein and sigmoid sinus.He received 3 weeks of conservative treatment and fully recovered.Overdrainage of cerebrospinal fluid and head rotation with undeveloped internal jugular vein may have resulted in this complication.This case is the first case in the literature with this event sequence and has some significance for revealing the mechanism of remote cerebellar hemorrhage occurrence after other supratentorial surgeries.

Insulators in operating state will produce partial discharge under the influence of pollution. Ultraviolet (UV) imaging technology is a new method for detecting insulator discharge. For the partial discharge of polluted insulators, this paper proposes an UV imaging detection method based on the iterative threshold segmentation method. To preprocess the image, the mathematical morphology algorithm is used to remove the discrete noises and the insulator discharge spot is accurately identified. By combining the quantized information of the spot area, the level of the polluted insulator is then detected and the UV images of the insulator are obtained by artificial experiments. The detection examples are provided to verify the feasibility and quality of the method.

Fully-enclosed space embodies a range of practical environments enclosed by conducting walls, such as space stations, man-made satellites, submarines, and aircrafts. Wireless communication and/or wireless power transmission are highly desired in some of the fully-enclosed environments. In this paper, semi-analytical modal analysis is conducted for the purpose of char-acterizing wireless channels in fully-enclosed space. The modal analysis is based upon integral equation method. Cavity Green’s function in the spectral domain (that is, expressed in term of cavity modes) is employed in the integral equation. A cubic cavity with side length 1 meter is analyzed as a specific example, and the modal analysis results are verified by experiments. Measurement data agree with the theoretical analysis very well. As predicted by the theoretical analysis, excellent wireless channels associated with TM 220 mode (with bandwidth of 40 MHz), TM 310 mode (with bandwidth of 10 MHz), and TM 311 mode (with bandwidth of 20 MHz) are demonstrated inside a cubic box with side length of 1 meter.

In this paper, an optimized model extended from single train braking predictive model is established. This model can use the data of past Nth trains to predict the train pipe output of (N + 1)th train for long-grouped train braking system. The simulation results show that this model can predict the following time series data in accordance with the experimental results with high accuracy, which means that the model has good predictive performance. The test results can help build an intelligent semi-physical freight train braking platform with long-grouped numbers.

This paper describes a 2D tunable frequency selective absorber that incorporates a liquid metal and NaOH solution. The structure consists of circular chambers and small steps on a 3D printed substrate, where the radius of liquid metal [eutectic gallium indium (EGaIn)] can be controlled by electrochemical method. The novelty of the proposed design lies in its reconfigurable response, depending on the size of EGaIn on a 2D surface. By changing the radius of EGaIn, the unit cell of frequency selective absorber is capable of achieving four tunable states in simulation. Experimental results show the circular EGaIn patch can be easily created and controlled by DC bias, and produces a tunable absorption peak of 25-30 dB.

By combining a Substrate-Integrated Waveguide-feed magneto-electric dipole antenna and a dielectric plate lens, a new broadband high-gain magneto-electric dipole antenna is proposed, especially for the new unlicensed frequency band. Due to the addition of dielectric plate lens, the gain of the original magneto-electric dipole antenna is significantly improved. The proposed antenna has a simple structure and is very easy to manufacture. The proposed antenna achieves a simulated impedance bandwidth of 51.9% covering 44.7 GHz to 76 GHz. It fully includes the new unlicensed frequency band (57-71 GHz) in the new 5G standard. The maximum gain in the Z-direction is up to 16.3 dBi. The proposed antenna has the advantages of high gain, wide bandwidth, simple structure, low cross-polarization and low back radiation level.

Today, in order to overcome the low flexibility and low openness of traditional hardware communication systems, software-based software radio platforms have emerged. In order to more flexibly test the design of 3-bit tag passive wireless RFID strain patch antenna, this paper chooses to use energy detection algorithm on USRP to monitor the change of its resonant frequency. Second-order variable step detection is proposed to balance the sampling resolution and time cost, making spectrum sensing more intelligent. Good experimental results have been obtained, which provides a way to broaden the scope of application and reduce costs.

in today’s rapid development of digital technology, electronic-technology-related majors have been fully developed as well. As for students, during their professional learning process, the courses of digital circuits and logical programming are the most important professional basic courses in electrical engineering. This paper proposes some measures to improve the teaching method of these courses based on the Conceive-Design-Implement-Operate (CDIO) teaching module. Over the years of teaching practice, it has been proved that transformation of education method can improve the students’ learning skill in round way, stimulate learning interest and greatly enhance teaching effect. This paper addresses the transformation method in both theoretical and practical aspects and how to implement the proposed method in real teaching activities. This will induce great guiding value in digital electronic courses, and thus promote the development of semiconductor device and digital circuits. The courses could be the joint places where theoretical and practical knowledge properly merges, therefore the teaching reform can be well implemented with their help in the CDIO mode.