Dual-coupling effect enables a high-performance self-powered UV photodetector.

Self-powered ultraviolet photodetectors generally operate by utilizing the built-in electric field within heterojunctions or Schottky junctions. However, the effectiveness of self-powered detection is severely limited by the weak built-in electric field. Hence, advances in modulating the built-in electric field within heterojunctions are crucial for performance breakthroughs. Here, we suggest a method to enhance the built-in electric field by taking advantage of the dual-coupling effect between heterojunction and the self-polarization field of ferroelectrics. Under zero bias, the fabricated AgNWs/TiO2/PZT/GaN device achieves a responsivity of 184.31 mA/W and a specific detectivity of 1.7 × 1013 Jones, with an on/off ratio of 8.2 × 106 and rise/decay times reaching 0.16 ms/0.98 ms, respectively. The outstanding properties are primarily attributed to the substantial self-polarization of PZT induced by the p-GaN and the subsequent enhancement of the built-in electric field of the TiO2/PZT heterojunction. Under UV illumination, the dual coupling of the enhanced heterojunction and the self-polarizing field synergistically boost the photo-generated carrier separation and transport, leading to breakthroughs in ferroelectric-based self-powered photodetectors.

Dual-Band Frequency Selective Surface with Different Polarization Selectivity for Wireless Communication Application.

This article proposes a dual-band, frequency- and polarization-selective surface. Multiple resonant modes are introduced using the U-shaped resonator with a ground via to achieve dual-band responses and polarization selectivity. Two symmetrically grounded U-shaped resonators are coupled through electrically coupled apertures in a common ground, resulting in a passband with two transmission zeros per polarization. A general design flowchart and additional examples at the S, X, and K-bands are presented as well. A prototype at X-band is analyzed, fabricated, and measured, showing the passband center frequencies of 9.68 GHz and 10.73 GHz, factional bandwidths of 3.45% and 3.48%, and insertion losses of 0.9 dB and 1.1 dB, respectively. Due to the high selectivity, small frequency ratio, low profile, and stable performance under oblique incidence, the proposed designs have application potential in wireless communication systems.

Gastrointestinal symptoms of 95 cases with SARS-CoV-2 infection.

OBJECTIVE: To study the GI symptoms in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infected patients. DESIGN: We analysed epidemiological, demographic, clinical and laboratory data of 95 cases with SARS-CoV-2 caused coronavirus disease 2019. Real-time reverse transcriptase PCR was used to detect the presence of SARS-CoV-2 in faeces and GI tissues. RESULTS: Among the 95 patients, 58 cases exhibited GI symptoms of which 11 (11.6%) occurred on admission and 47 (49.5%) developed during hospitalisation. Diarrhoea (24.2%), anorexia (17.9%) and nausea (17.9%) were the main symptoms with five (5.3%), five (5.3%) and three (3.2%) cases occurred on the illness onset, respectively. A substantial proportion of patients developed diarrhoea during hospitalisation, potentially aggravated by various drugs including antibiotics. Faecal samples of 65 hospitalised patients were tested for the presence of SARS-CoV-2, including 42 with and 23 without GI symptoms, of which 22 (52.4%) and 9 (39.1%) were positive, respectively. Six patients with GI symptoms were subjected to endoscopy, revealing oesophageal bleeding with erosions and ulcers in one severe patient. SARS-CoV-2 RNA was detected in oesophagus, stomach, duodenum and rectum specimens for both two severe patients. In contrast, only duodenum was positive in one of the four non-severe patients. CONCLUSIONS: GI tract may be a potential transmission route and target organ of SARS-CoV-2.

Practical Experience of Endoscope Reprocessing and Working-Platform Disinfection in COVID-19 Patients: A Report from Guangdong China during the Pandemic.

BACKGROUND: No consensus exists regarding which procedures should be performed to disinfect endoscopes and working platforms after COVID-19 patients have undergone endoscopy. METHODS: We analyzed the disinfection quality of endoscopes and working platforms after 11 COVID-19 patients had undergone endoscopy. CONCLUSIONS: For endoscopic preprocessing at the bedside, a key disinfection step is using a multienzyme stock solution. The nucleic acid tests for endoscopists, washers, endoscopes, and working platforms were all negative. Based on our experience with the 11 COVID-19 patients who had undergone endoscopy, we provide an endoscopic reprocessing method for the bedside endoscopic diagnosis and treatment of COVID-19 patients for reference.

3D Radiation Pattern Reconfigurable Phased Array for Transmission Angle Sensing in 5G Mobile Communication.

This paper proposes a 3D radiation pattern reconfigurable antenna (RPRA) and a reconfigurable phased array (RPA) for 5G mobile communication. The antenna and array are working at 28 GHz, which is selected as a 5G communication band in many countries. The proposed phased array will be applied as sensors to find out the optimal transmitting⁻receiving angle in a randomly changed cellular wireless scenarios. The RPRA and RPA are fed by Substrate Integrated Waveguide (SIW) and have three switchable radiation modes: Broadside 1, Broadside 2 and Endfire. The three modes correspond to three different radiation patterns and each of them covers a different area in the Azimuth plane. An eight-element phased array constructed by the proposed RPRA, which is able to switch beam in Azimuth plane and scan in the Elevation plane, is also presented in this paper. The proposed RPA is able to provide much higher spatial coverage than the conventional phased arrays and without additional feeding and phase shifting networks. The beam switching is realized by the PIN diodes. The proposed antenna and array have planer structures and require small clearance on the ground plane which makes them compatible with mobile phones. The simulations show good performance for both RPRA and RPA.