Band Devices Research Articles

CsPbBr3 perovskite quantum dots/p-GaN heterojunction for ultraviolet-visible spectrum photodetectors

All-inorganic perovskites have attracted increasing attention because of their strong environmental stability and excellent photoelectric properties. However, the limited spectral response range of perovskite photodetectors restricts them in practical applications. In this work, an ultraviolet–visible photodetector with a wide spectral response and a high responsivity was prepared by constructing a CsPbBr3 quantum dots (QDs)/p-GaN heterojunction. The type-II energy band alignment formed by the heterojunction is conducive to the transport of photogenerated carriers, resulting in a high responsivity. Under certain conditions, the device can obtain responsivity values of 5 A/W and 850 mA/W under 350 and 725 nm illumination, respectively, which are comparable to those of other perovskite-based photodetectors. In addition, the photoresponse mechanism of the device is revealed through first-principles calculations of the heterojunction and the device. The enhanced light absorption of the heterojunction and the special band bending under different bias voltages improve the photoelectric performance of the device. This work can provide valuable insights into high-performance photodetectors based on all-inorganic perovskite QDs heterojunctions in terms of band regulation and device performance improvement.

Justification of the criterion for technical synthesis of radar complexes for covert airspace control

For covert control of airspace, it is required to use complexes that meet the requirements for the effectiveness of obtaining data on objects in the field of observations and protection against the detection of their own unmasking signs by means of radio technical monitoring with predetermined indicators of resource intensity and efficiency of performing target functions. Joint fulfillment of these requirements when the parameters of the equipment structures and information processes are found under the established conditions for monitoring the properties of resource intensity and efficiency is achieved. Due to the complexity and inconsistency of the dependent bridges of the performance indicators and the stealth of application from the technical characteristics of the radar systems, it is necessary to substantiate the synthesis criterion for finding compromise technical solutions for the design of the equipment and the choice of a strategy for obtaining data on air facilities. The goal of the article is determination of design characteristics, frequency-time and energy signals parameters of radar complexes for analysis of air situation at concealment of unmasking features from means of radio technical monitoring. The criterion of technical synthesis of radar complexes for covert control of air-space is justified, which allows obtaining information about air objects at pre-established risks of threats to identify their own unmasking signs by means of radio technical monitoring. Regularities have been investigated and the conditions for achieving the target functions of complexes with resonant, band and frequency-independent signal transmission-reception devices have been determined. The principles of construction have been substantiated and the rules for finding rational parameters of the design of radar complexes and information processes used in airspace control in order to achieve the required operational properties of obtaining information about air objects while maintaining secrecy from radio monitoring facilities have been determined.

Selenization post-treatment Ag-alloyed Cu2ZnSn(S,Se)4 films for enhancing photovoltaic performance of solar cells

The Ag-alloyed Cu1.9Ag0.1ZnSn(S,Se)4 (CAZTSSe) films were prepared by selenidation of Cu1.9Ag0.1ZnSnS4 (CAZTS) precursor films under various selenidation conditions. The effects of selenidation time and selenidation temperature on the composition, morphology, optical band gap (Eg) and device performance of CAZTSSe films were systematically studied. It is found that the selenidation temperature of 480 °C and selenidation time of 10 min provide a favorable selenidation environment for the growth of the film, which can promote grain growth and form a thick and smooth film. This has been strongly confirmed through relevant tests. In addition, the analysis of performance characterization of the films shows that the Eg of the films can be adjusted via adjusting the selenidation conditions, so as to improve the electrical properties. Finally, the CAZTSSe solar cell with a photoelectric conversion efficiency (PCE) of 5.94 % and an open circuit voltage (Voc) of 397 mV was successfully prepared at the selenidation temperature of 480 °C and selenidation time of 10 min.

A novel Architecture for Sensor-based Rescue Management using Smart Band and Handheld Device Prototypes based on Low-Power Wireless Technology

A novel Architecture for Sensor-based Rescue Management using Smart Band and Handheld Device Prototypes based on Low-Power Wireless Technology

Comparison of Radial Artery Occlusion Occurrence Between Compression Band Device and Manually Applied Gauze Compression After Transradial Coronary Procedure

INTRODUCTION: Hemostasis of the radial artery after transradial coronary procedure can be achieved either manually by means of a gauze or through a device compression band, and radial artery occlusion (RAO) is one of its common complications. The study sought to compare the occurrence of RAO between the two hemostasis methods being used after a transradial coronary procedure. METHODS: This was a prospective, randomized, open-label, blinded endpoint study. A total of 137 patients undergoing a transradial coronary procedure were randomized equally using block randomization sampling technique. Radial artery patency was evaluated by color duplex ultrasonography within 24 to 72 hours after the procedure. The primary endpoint was early RAO. Secondary endpoints included complications such as access-site bleeding, pain, and hematoma. RESULTS: Three (2.19%) early RAOs occurred: one (1.47%) in the band compression device group and two (2.9%) in the manual gauze compression group (P = 1.000). There were no significant differences between the two groups regarding access-site bleeding (type 1 bleeding, 3 [4.48%] vs 2 [2.90%]; P = 0.678), pain (median pain score of 0 [0–6] vs 0 [0–7]; P = 0.742), and hematoma (grade I: 3 [4.41%]vs 2 [2.9%]; grade II: 0 vs 2 [2.9%]; grade III: none, and grade IV: 0 vs 2 [2.9%]) (P = 0.363). DISCUSSION: Compression band device and manually applied gauze compression have similar rates of early RAO, access-site bleeding, pain, and hematoma. KEYWORDS: compression band device, hemostasis, manual gauze compression, radial artery occlusion

Comparison of radial artery occlusion occurrence (RAO) between compression band device and manually applied gauze compression after transradial coronary procedure, a PROBE study

Abstract Funding Acknowledgements Type of funding sources: None. Background Hemostasis of the radial artery after transradial coronary procedure can be achieved either manually by means of a gauze or mechanically through a device compression band, and radial artery occlusion (RAO) is one of its common complications. Purpose The study sought to compare the occurrence of RAO between the two hemostasis methods being used after a transradial coronary procedure to determine an effective and safe method that can be recommended for use. Methodology This was a Prospective, Randomized Open-label Blinded Endpoint (PROBE) study. A total of 137 patients undergoing a transradial coronary procedure were randomized equally using block randomization sampling technique. Radial artery patency was evaluated by color duplex ultrasonography within 24-72 hours after the procedure. The primary endpoint was early RAO. Secondary endpoints included complications such as access-site bleeding, pain, and hematoma. Results Three (2.19%) early RAOs occurred, 1 (1.47%) in the band compression device group and 2 (2.9%) in the manual gauze compression group (p= 1.000). There were no significant differences between the 2 groups regarding access-site bleeding [type 1 bleeding, 3 (4.48%) vs 2 (2.90%); p= 0.678]; pain with median pain score of 0 (0-6) vs 0 (0-7); p= 0.742; and hematoma [Grade I: 3 (4.41%)vs 2 (2.9%); Grade II: 0 vs 2 (2.9%); Grade III: none, and Grade IV: 0 vs 2 (2.9%); p= 0.363]. Conclusion Compression Band Device and Manually Applied Gauze Compression have similar rates of early RAO, access-site bleeding, pain, and hematoma.

Post-mortem digital forensics analysis of the Zepp Life android application

This paper studies the post-mortem digital forensic artifacts left by the Android ZeppLife (formerly MiFit) mobile application when used in conjunction with a Xiaomi MiBand 6. The MiBand 6 is a low-cost smart band device with several sensors that allow for health and activity monitoring, collecting metrics such as heart rate, blood oxygen saturation level, and step count. The device communicates via Bluetooth Low Energy with the ZeppLife application, which displays its data, provides some controls, and acts as a bridge to the Internet.We study, from a digital forensics perspective, the Android version of the mobile application in a rooted smartphone. For this purpose, we analyze the data repositories, namely its databases and XML files, and correlate the data on the smartphone with the corresponding usage of the Mi Band device. The paper also presents two open-source scripts we have developed to ease the task of forensic practitioners dealing with ZeppLife/MiBand 6: ZL_std and ZL_autopsy. The former refers to a Python 3 script that extracts high-level views of Zepp Life data through the command-line, whereas the latter is a module that integrates ZL_std functionalities within the popular open-source Autopsy digital forensic software. Data stored on the Android companion device of a MiBand 6 might include GPS coordinates, events and alarms, and biometric data such as heart rate, sleep time, and fitness activity, which can be valuable digital forensic artifacts.

Liquid Crystal-Tuned Planar Optics in Terahertz Range

Recently, terahertz waves of higher frequencies compared to microwave and radio frequency have shown great potential in radar detection and high-speed wireless communication. To spatially control the wavefront of terahertz beams, various novel components, such as terahertz filters, polarization converters and lenses, have been investigated. Metamaterials and metasurfaces have become the most promising technique for the free manipulation of terahertz waves. Metadevices integrated with liquid crystals have been widely used in active terahertz devices. In this review, the birefringence of liquid crystals in the terahertz band and terahertz devices based on liquid crystals are summarized. By integrating liquid crystals with plasmonic metamaterials, the functions become dynamically adjustable and are reconstructed. Utilizing liquid crystals to change the resonance of metamaterials, tunable filters, absorbers, and programmable metasurfaces are realized. To solve the problem of low efficiency, terahertz wavefront shaping devices based on dielectric metasurfaces and liquid crystals, such as a variable deflection angle grating and zoom metalenses, are presented. Finally, we discuss and anticipate the future developments of liquid-crystal-integrated meta-devices, which will inspire broad applications in terahertz communication and imaging.

A Direct Near-Field Observation of Conversion Between Waveguide Modes and Leaky Modes in Periodic Metal Structures

In order to directly observe the conversion between guided-wave modes and leaky-wave modes in a periodic structure, quadrilateral periodic metal diaphragms arranged in two ways on metal surfaces were analyzed. In the first scheme, each unit cell in the periodic structure contains a metal diaphragm, of which the dispersion characteristics of periodic structures were analyzed by the finite element method. The results of the numerical show that by adjusting lattice constants of periodic structures and geometrical parameters of metal diaphragms, the transmission bandwidth of the present 1-D periodic metal diaphragm structures could be limited to X-band, where the transmission characteristics are easy to be measured. In the second scheme, a pair of mirror-symmetric and staggered quadrilateral metal diaphragms is introduced into a unit cell. It can be found in the theoretical calculation that a new dispersion curve, which passes through the light line in a high frequency range, can be exhibited. The propagation constants of dispersion curves become complex numbers and provide highly directional electromagnetic radiation that scans as the frequency changes. After the relative positions of the two metal diaphragms were properly adjusted, the frequency range of the forbidden band gap between two dispersion curves can be minimized, so as to increase the transmission bandwidth of the 1-D periodic metal structures. The experimentally measured show that the dispersion curves of the two periodic structures were highly consistent with the theoretical results. The narrowing of the band gap could be verified by measuring the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i> -parameters. The near-field measurement of the periodic metal structures can demonstrate the conversion between the guided-wave modes and the leaky-wave modes, and the far-field measurement can show the frequency dependence of beam elevation. We expect that these artificial material structures could be widely used for designing new microwave and terahertz band devices.

5G: Overview, Challenges and Benefits

Abstract: 5G Is a advances technology in world around us but also dynamic the wireless industry to develop the next generation of network technology. December 1, 2018, South Korea became the first country to offer 5G.5G is a high frequency band and different device support are 5G.5G main advantages is high speed and effective and efficiency technology.5G is wireless backhaul connection or high bandwidth optical fibber.

Stabilizing Buried Interface via Synergistic Effect of Fluorine and Sulfonyl Functional Groups Toward Efficient and Stable Perovskite Solar Cells

HighlightsAn effective buried interface stabilization strategy based on synergistic effect of fluorine and sulfonyl functional groups is proposed.The correlations between molecular structures, defect passivation, interfacial energy band alignment, perovskite crystallization and device performance are established.The device with KFSI achieves an impressive efficiency of 24.17%.

An unconventional vertical fluidic-controlled wearable platform for synchronously detecting sweat rate and electrolyte concentration

Epidermal microfluidic devices with long microchannels have been developed for continuous sweat analysis, which are crucial to assess personal hydration status and underlying health conditions. However, the flow resistance in long channels and the ionic concentration variation significantly affect the accuracy of both the sweat rate and electrolyte concentration measurements. Herein, we present a novel fluidic-controlled wearable platform for synchronously dropwise-detecting the sweat rate and total electrolyte concentration. The unconventional platform consisting of a vertically shortened channel, a pair of embedded electrodes and an absorption layer, is designed to minimize the flow resistance and transform sweat fluidics into uniform micro-droplets for chronological and dropwise detection. Real-time sweat conductance is decoupled from a square-wave-like curve, where the sweat rate and electrolyte concentration can be derived from the interval time and peak value, respectively. Flexible and wearable band devices are demonstrated to show their potential application for hydration status assessment during exercises.

Arthroscopically Assisted Acromioclavicular and Coracoclavicular Reconstruction with a Looped Braided Polyester Suture Band and Buckle Device

Acromioclavicular (AC) joint injuries occur with a traumatic load to the lateral aspect of the shoulder and account for 9% of all shoulder girdle injuries. Rockwood classified AC joint injuries as type I though type VI, based on severity of injury, radiographic findings, and reducibility of the AC joint. Type I and II injuries are typically managed nonoperatively, whereas type IV, V, and VI are managed operatively to address the significant soft tissue disruption, persistent AC joint instability, and apical shoulder deformation. Treatment of type III injuries remain controversial. Several techniques have been described to treat AC joint injuries with no consensus for optimal treatment. “Anatomic” double-tunnel coracoclavicular ligament reconstruction is one currently popular technique to address AC joint injuries; however, clavicle and coracoid fractures are well-described complications of this technique. The objective of this technical report is to describe our preferred technique to address AC joint injuries. This technique involves using a looped braided polyester prosthetic band and low-profile buckle with allograft augmentation using a device to pass materials around the coracoid process.

Anchoring of halogen-cleaved organic ligands on perovskite surfaces

Photoemission spectroscopy reveals halogen cleavage from bulky cation organics and the formation process of 2D-like perovskites on the parent perovskite as well as their impact on band alignment and device performance.

Peritonitis and splenitis caused by MAC-infection in an immunosuppressed patient

Primary (hematogenic) peritonitis caused by non-tuberculosis mycobacteria is extremely rare in the clinical practice. The main number of reported episodes of primary intraabdominal infection is associated with M. tuberculosis and the development of granulomatous inflammation of the peritoneum visually similar to carcinomatosis. The vast majority of reports of peritonitis associated with non-tuberculosis mycobacteria are interlinked with chronic peritoneal dialysis or foreign bodies of the abdominal cavity, when an infection is carried out by the contact through a dialysis catheter, prosthesis or a gastric banding device. The article describes a clinical case of peritonitis and splenitis caused by M. avium with hematogenic spread of infection from the primary pulmonary focus in a young patient with immunosuppression. Diagnosis of such peritonitis at the preoperative stage is extremely difficult due to the similarity of symptoms with atypical appendicitis or infected ascites. The intraoperative picture also did not allow us to assume a mycobacterial etiology of the process, and the absence of a focal point of peritonitis made it necessary to thoroughly understand the situation. Only a peritoneal biopsy and a complete laboratory examination of exudate allowed us to verify the diagnosis, to understand the pathogenetic mechanisms of the disease and to start a timely etiotropic therapy.

Growth modulation through hemiepiphysiodesis : Novel surgical techniques: risks and progress

The correction of angular deformities of the lower limb is a key task in paediatric orthopaedic surgery. The growth potential of the physis can be employed for the correction of these malalignments in childhood and adolescence. Hemiepiphysiodesis (HED) is asurgical technique used for growth modulation by permanent or temporary asymmetrical arrest of the growth plate. In permanent HED, exact timing of the procedure is mandatory to achieve optimal correction. Temporary HED through tension band devices such as two-hole-plates or flexible staples has been established as the treatment of choice for growth guidance with excellent results. Implant-associated complications have been significantly reduced through implant modifications. Several experimental procedures have the potential to achieve growth modulation even without the requirement of surgical intervention.

An evaluation of resectability among endoscopic treatment methods for rectal neuroendocrine tumors

Background and Study AimsWith respect to rectal neuroendocrine tumor (NET) resection, it remains unclear which of the following methods is the most effective: conventional endoscopic mucosal resection (cEMR), EMR using a fitted cap (EMR-C), EMR with a ligation band device (EMR-L), or endoscopic submucosal dissection (ESD). Thus, in this study, we aim to retrospectively evaluate the most effective endoscopic resection for rectal NETs < 10 mm. Patients and methodsIn total, 61 consecutive patients with primary rectal NETs < 10 mm in diameter were included in this study; they were then divided into three groups: those with cEMR; those with modified EMR (mEMR) involving EMR-C and EMR-L; and those with ESD. The primary endpoint was to evaluate the difference in the complete en bloc resection rate. The secondary endpoint was to investigate differences in procedure time and complications. ResultsAmong the three groups, a significant difference was found in procedure time (cEMR vs ESD, P < .01; mEMR vs ESD, P < .01), en bloc resection rate (cEMR vs mEMR, P = .015), tumor size (mEMR vs ESD, P < .01), percentage of tumor diameter ≥ 5 mm (mEMR vs ESD, P < .01), and complete en bloc resection rate (cEMR vs mEMR, P = .014). Meanwhile, no significant difference was noted in terms of complication rate among the three groups. ConclusionThe mEMR was the most suitable resection method for rectal NETs < 10 mm with respect to the risks and benefits from procedure-related factors, such as complete en bloc resection rate, procedure time, and complication rate.

Human Sensing in Reverberant Environments: RF-Based Occupancy and Fall Detection in Ships

In this paper, we explore the possibility of estimating the number of people inside a below-deck ship compartment using the theory of room electromagnetics. Most RF-based occupancy detection solutions focus on residential environments. Confined metallic spaces such in industrial environments are more hostile and exhibit features of a reverberant cavity. The theory of room electromagnetics provides a simple characterization of microwave propagation in such environments. By considering the indoor environment as a lossy cavity, the exponential decay rate of the power-delay profile (PDP), also known as reverberation time (RT), is related to the total absorption inside the room. First, we verify the reverberating nature of the room by measuring the RT at different locations inside the room. The PDPs are calculated from the channel impulse response (CIR) measured using the MIMOSA radio channel sounder. Then, the relation between RT and the number of people inside the room is investigated. We show that it is possible to estimate the number of stationary people with a good accuracy, depending on the number of antennas used. With a success rate of 88%, the estimation error is only one person when 16 spatially averaged PDPs are used. Higher success rates are achievable with more spatial averaging. Moreover, off-the-shelf (OTS) ultra wide band (UWB) devices are used to estimate the number of people inside the same room. Results show that temporal averaging of PDPs can further improve the success rate to 95% when people inside the room are moving. In addition, the detection of a lone person falling to the ground is investigated based on the Doppler analysis of the measured CIRs. It is shown that the Doppler spread in case of a fall has higher peak values compared to normal activities, such as walking and sitting. With the use of a simple Bayes classifier, a fall is detected with 98% accuracy and 100% sensitivity.

Reliability of a smartphone application to measure physical activity

ABSTRACT The aim of this study was to evaluate how accurate is a smartphone app to measure a physical activity parameter (steps). Physical Education undergraduate students (n = 46), both male and female, were recruited. A tally counter, a validated device (Xiaomi Mi Band 2®) and My Active Life app were used to perform the steps count. Each participant took three low-intensity treadmill walks (5 km h−1), with a number of target steps (500-, 1000- and 1500-steps walk). Visual agreement analyses was performed through Bland-Altman plots. There was no significant interaction between steps walks and device during treadmill walking test (F (2,84) = 3.854; p = 0.07). Differences in steps measured by Mi Band were not different from 0 in 500-steps walk (p = 0.243) and 1000-steps walk (p = 0.350), and in My Active Life in 500-steps walk (p = 0.177) and 1500-steps walk (p = 0.221). Bland-Altman analyses indicated an acceptable agreement between My active Life app and Mi Band devices for 1000-steps walk (−359.01; 310.43) and 1500-steps walk (−572.97; 377.11). In conclusion, My Active Life app showed accuracy in measuring total steps, in longer walking activities (e.g. higher than 1000 steps), and can be used on a daily basis and in research setting.

On the Seasonality of the Snow Optical Behaviour at Ny Ålesund (Svalbard Islands, Norway)

Polar areas are the most sensitive targets of climate change. From this perspective, the continuous monitoring of the cryosphere represents a critical need, which, now, we can only partially supply with specific satellite missions. The integration between remote-sensed multi-spectral images and field data is crucial to validate retrieval algorithms and climatological models. The optical behavior of snow, at different wavelengths, provides significant information about the microphysical characteristics of the surface in addition to the spatial distribution of snow/ice covers. This work presents the unmanned apparatus installed at Ny Ålesund (Svalbard) that provides continuous spectral surface albedo. A narrow band device was compared to a full-range system, to remotely sensed data during the 2015 spring/summer period at the Amundsen-Nobile Climate Change Tower. The system was integrated with a camera aimed to acquire sky and ground images. The results confirmed the possibility of making continuous observations of the snow surface and highlighted the opportunity to monitor the spectral variations of snowed surfaces during the melting period.