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Non-contact temperature sensors utilising the fluorescence intensity ratio and the unique up-conversion (UC) luminescence of rare-earth ions have numerous benefits; however, their operational temperature range has remained limited. In this study, NaLuF4:Yb3+/Ho3+ samples were prepared by the hydrothermal method. The samples exhibited exceptional UC luminescence properties at low temperatures. The intensity of the green emission (with peak wavelengths of 540 and 546 nm) gradually decreased with increasing temperature, and the green emissions showed a unique change at low temperatures. In addition, we studied the dependence of the UC luminescence intensity on the excitation power and the variation in the decay lifetime with temperature. The experiments revealed excellent luminous performance and significantly enhanced sensitivity at low temperatures; the maximum absolute sensitivity Sa and relative sensitivity Sr of the 540 and 546 nm thermally coupled energy levels were 1.02% and 0.55% K−1, respectively. The potential temperature sensing properties of Yb3+/Ho3+-co-doped NaLuF4 makes it suitable for temperature sensing applications at temperatures as low as 30 K. This study offers a novel approach for the advancement of temperature sensing technology at low temperatures. [ABSTRACT FROM AUTHOR]

Multifunctional organic photodetectors (MFOPDs) have garnered significant attention due to their remarkable potential for integrating diverse device functionalities. In contrast to previous MFOPDs that have primarily emphasized the integration of various response bands, a pioneering multifunctional photodetector is introduced based on the P3HT:PC61BM system capable of selectively responding to both wavelength and polarization. Under positive bias, the device operates in a wide‐band, polarization‐insensitive mode, achieving an external quantum efficiency (EQE) of up to 7.01 × 104%. The EQE dichroic ratio (DR) of the device remains <1.01 (at 650 nm). Conversely, under negative bias, the device transitions into a narrow‐band, polarization‐sensitive mode, achieving an EQE of up to 4.82 × 104% with a narrow full width at half maximum (FWHM) of only 25 nm at 650 nm. The EQE DR exceeds 10 in this mode, marking it as one of the highest values within the field of polarization‐sensitive organic photodetectors. This versatile operation is made possible through the strategic use of double‐sided barriers, an oriented light harvesting layer, and a charge injection narrowing (CIN) approach. This work represents a significant advancement toward the realization of multifunctional photodetectors capable of selecting response bands and polarization sensitivity. [ABSTRACT FROM AUTHOR]

A dual-band, dual-mode button antenna is proposed for emerging fifth-generation (5G) networks and Industrial, Scientific, and Medical (ISM) communication systems, as it operates at 3.5 GHz and 5.8 GHz, respectively. At the lower band, a monopole-like omnidirectional radiation pattern is achieved by loading shorting pins on curved strips for on-body communication. At the higher band, broadside circularly polarized radiation is achieved by loading an asymmetric U-shaped slot in the central chamferd patch for off-body communication. By using Characteristic Modal Analysis (CMA), a clear physical insight into the formation of dual polarization is provided. The −10 dB impedance bandwidth ranges from 3.48 to 3.60 GHz and 5.65 to 6.03 GHz, respectively. The 3 dB axial ratio (AR) bandwidth ranges from 5.71 to 5.85 GHz in the high band. Additionally, the antenna achieves a peak gain of 1.2 dBi in on-body mode and 6.9 dBi in off-body mode. The maximum specific absorption rate (SAR) calculated on the body tissues is below the US/EU standard thresholds of 1.6 W/kg and 2 W/kg. The measured results indicate that the antenna experiences only slight impact from human body loading and structural deformations. Given its notable features, the proposed design is well suited for Wireless Body Area Network (WBAN) applications. [ABSTRACT FROM AUTHOR]

Van der Waals (vdW) heterostructures, formed by stacking different two‐dimensional (2D) materials, have emerged as a promising platform for next‐generation optoelectronic devices through band engineering. While various all‐2D and mixed‐dimensional heterojunction phototransistors based on p–n junctions or Schottky junctions have been developed, their performance, often constrained by the trade‐off between responsivity (R) and response speed, limits their widespread application. Here, a dual‐mode phototransistor based on a MoTe2/WS2/WSe2 double vdW heterostructure is designed. The bottom WSe2 layer effectively modulates the entire MoTe2/WS2 heterojunction channel, enabling both photoconductive and photovoltaic modes with exceptional optoelectronic properties in a single device. Specifically, the proposed device exhibits a maximum R of 2540 A W−1 and an impressive specific detectivity of 8 × 1012 Jones under the photoconductive mode. Under the photovoltaic mode, it achieves a fast response speed of 35.3/49.1 µs and a high light on/off ratio of 2 × 105. Additionally, the device exhibits latent potential for high‐resolution imaging across various wavelengths and fast optical communication. This work offers a rational alternative for achieving dual‐mode photodetection and highlights its promising application prospects in imaging and optical communication. [ABSTRACT FROM AUTHOR]

In this study, we investigate micrometer-sized NaYF4 crystals double-doped with Yb3+/Er3+ lanthanide ions, designed for temperature-sensing applications. In contrast to previous studies, which focused predominantly on the high-temperature regime, our investigation spans a comprehensive range of both high and ultralow temperatures. We explore the relationship between temperature and the upconversion luminescence (UCL) spectra in both frequency and time domains. Our findings highlight the strong dependence of these spectral characteristics of lanthanide-doped NaYF4 crystals on temperature. Furthermore, we introduce a dual-mode luminescence temperature measurement technique, leveraging the upconversion emission intensity ratio for both green and red emissions. This study also examines the correlation between temperature sensing, energy level disparities, and thermal coupling in Er3+ ions across various temperature scales. Our research contributes to advancing the understanding and application of lanthanide-doped materials, setting a foundation for future innovations in temperature sensing across diverse fields. [ABSTRACT FROM AUTHOR]

Summary: The paper discusses about the design and analysis of a unique circular printed antenna with quatrefoil‐shaped slots and meta‐surface for body centric communications. The antenna design is progressed with a slots in quatrefoil shape carved on the patch placed on Taconic_LX substrate whose thickness is 1 mm. The footprint of the antenna is 32 × 24 × 1 mm3. The antenna's bandwidth is improved using defected ground. The proposed design operates from 2 to 14 GHz of the ultra‐wideband (UWB) spectrum, thus providing 143% bandwidth. The antenna exhibits good gain values of 2.5 and 6 dB at 2.45 and 5.8 GHz, respectively, with efficiency of 81% and 91%. At 2.45 GHz, the design proposed functions in on‐body mode, and at 5.8 GHz, it functions in off‐body mode. Specific absorption rate (SAR) analysis was carried out whose results are within the safety range of health measures. Bending analysis was also done to enhance the antenna's applicability. Path loss, fidelity, and group delay analysis are done. The simulated results were validated by fabricating and testing the prototype. On‐body testing of the fabricated antenna was also done at various body locations. The measured results were found to be in good agreement with the simulated results. [ABSTRACT FROM AUTHOR]

Household power conversion stages process significant amounts of power when they add up to form a microgrid. Microinverters are considered one of the best choices to utilize the renewable energy harvested power. Microinverter integration encounters several challenges when interfaced with expanding microgrids. This paper proposes a coupled inductor-based boost microinverter operating in dual mode time sharing technique for renewable energy applications. It is composed of an absolute sinewave modulated voltage boost converter and series capacitor connected to the secondary winding of the coupled inductor followed by a single-phase Full bridge inverter. The coupled inductor integration allows a significant reduction in current ripple and improved energy conversion efficiency. In the proposed microinverter, the DC link voltage is not required to be constant, instead, it process an absolute sinewave modulated voltage and then it is unfolded to AC and fed into the grid. The DC link capacitor is substituted by an efficient AC thin film type capacitor. The dual mode time-sharing principle intends to reduce the switching losses of the microinverter and consequently achieves high conversion efficiency. The proposed converter’s analysis, design, and simulation are validated on a 2.0 kW setup system using PSIM simulation software. The feasibility and performance of this new microinverter topology is proved experimentally via laboratory prototype. The current ripple can be reduced to one half in case of matching coupled inductor primary and secondary windings compared to the typical boost converter. In another scenario, the current ripple can be fully eliminated in either of the coupled inductor windings when winding inductance equals to the mutual inductance. The proposed microinverter topology offers a notable enhancement in power conversion performance that reached 97%. In addition, a high-quality sinusoidal output current waveform of 1.1% total harmonic distortion is achieved.

In this article, a low profile aperture coupled single and dual band higher order bandpass frequency selective surface (FSS) is proposed. Initially, a basic patch resonator with L-shape truncated corner is investigated theoretically so that two orthogonal modes can be excited simultaneously. Next, to avoid the cross-polarized reflection produced by two orthogonal modes, a combination of four such L-shape truncated patch resonators with 90° between two adjoining patches are implemented and analyzed.Further, by arranging two of such combination resonators placed back-to-back manner through aperture coupling metallic layer in middle, a three layer single mode fourth order and a dual band second order bandpass FSS is designed. The proposed bandpass FSS enables higher order bandpass FSSs where the order of the modes is twice than traditional aperture coupled patch resonators (AC-PRs). It provides more flexibility at higher order filtering responses. To endorse the design concept, a single and dual bandpass FSS is simulated to initiate magnetic and electric coupling through the aperture metallic layer. Moreover, an equivalent circuit model for the even and odd mode analysis method is examined the principle of operation. Finally, the proposed bandpass FSS is fabricated and tested in a vector network analyzer (VNA) setup. The measured and simulated results are compared and validated.

Non-contact temperature sensors utilising the fluorescence intensity ratio and the unique up-conversion (UC) luminescence of rare-earth ions have numerous benefits; however, their operational temperature range has remained limited. In this study, NaLuF4:Yb3+/Ho3+ samples were prepared by the hydrothermal method. The samples exhibited exceptional UC luminescence properties at low temperatures. The intensity of the green emission (with peak wavelengths of 540 and 546 nm) gradually decreased with increasing temperature, and the green emissions showed a unique change at low temperatures. In addition, we studied the dependence of the UC luminescence intensity on the excitation power and the variation in the decay lifetime with temperature. The experiments revealed excellent luminous performance and significantly enhanced sensitivity at low temperatures; the maximum absolute sensitivity Sa and relative sensitivity Sr of the 540 and 546 nm thermally coupled energy levels were 1.02% and 0.55% K−1, respectively. The potential temperature sensing properties of Yb3+/Ho3+-co-doped NaLuF4 makes it suitable for temperature sensing applications at temperatures as low as 30 K. This study offers a novel approach for the advancement of temperature sensing technology at low temperatures.

In this study, we investigate micrometer-sized NaYF4 crystals double-doped with Yb3+/Er3+ lanthanide ions, designed for temperature-sensing applications. In contrast to previous studies, which focused predominantly on the high-temperature regime, our investigation spans a comprehensive range of both high and ultralow temperatures. We explore the relationship between temperature and the upconversion luminescence (UCL) spectra in both frequency and time domains. Our findings highlight the strong dependence of these spectral characteristics of lanthanide-doped NaYF4 crystals on temperature. Furthermore, we introduce a dual-mode luminescence temperature measurement technique, leveraging the upconversion emission intensity ratio for both green and red emissions. This study also examines the correlation between temperature sensing, energy level disparities, and thermal coupling in Er3+ ions across various temperature scales. Our research contributes to advancing the understanding and application of lanthanide-doped materials, setting a foundation for future innovations in temperature sensing across diverse fields.

The ultrasonic transducer is an indispensably critical component for sound velocity measurement. With the increasing demand of high-temperature ultrasonic dual mode transducer applicable to cubic-anvil apparatus, where experiments of high-pressure and high-temperature sound velocity are routinely conducted, a PZT-based ultrasonic dual modetransducer was presented iii this study. It was made of a sandwich of two PZT piezoceramic wai'ers, the upper one generating P-waves and the lower one genet* ating S-waves. The transducer was directly bonded onto a WC anvil of cubic-anvil apparatus using high-temperature adhesive. and then heated in an oven while measuring the bottom echoes from the WC anvil. The results showed that the high-temperature transducer could work up to 140 °C. The transducer features low cost, easy fabricating, and highquality signals, and so we believe it is useful for sound velocity measurement at high temperatures in cubic-anvi] apparatus. [ABSTRACT FROM AUTHOR]

A 3.3 V mode-switching RF CMOS power amplifier (PA) for WLAN applications is presented, which is integrated into a 55-nm bulk CMOS process. The proposed PA offers both static control and dynamic power control, allowing it to operate efficiently in both low-power and high-power modes. The pure low-power mode is achieved by reducing power cells, which are also used for linearization in high power mode. The low-power mode is achieved by reducing the number of power cells which are also used for linearization in the high-power mode. In the dynamic power control mode, the total AM–AM and AM–PM distortion is effectively compensated for by dynamically controlling the number of power cells and adjusting the matching input. The proposed PA achieves an output P1dB of 27.6 dBm with a PAE of 32.7% and an output P1dB of 17.7 dBm with a PAE of 10% in high-power and low-power modes, respectively. It is measured with an 802.11 n 64-quadrature-amplitude-modulation (MCS7) signal and shows a maximum average power of 19 dBm under an error-vector-magnitude (EVM) of −27 dB. [ABSTRACT FROM AUTHOR]

Cell injection system for biomedical engineering demands that actuators have large stroke, high resolution and speed for cell positioning and injection. Single mode piezoelectric actuators could meet some of these requirements but hardly all. Stick-slip actuator is easy to achieve high-speed operation, but it is prone to setback; The speed characteristics of the inchworm actuator are lower than those of the stick-slip actuator, but the step is more stable and the setback is lower. This study proposes an inchworm and stick-slip dual mode piezoelectric actuator (ISSPA) for cell injection. It integrates two working modes into one actuator and both modes drive the same slider. The stick-slip mode works at high frequency for fast positioning to the cell and the inchworm mode drives the needle to puncture the cell membrane and accurately locates to the specified location. The structure and working principle of the ISSPA are provided. A prototype of the proposed ISSPA is fabricated and experiments are conducted. When the driving voltage of the piezoelectric stack is 100 V and the frequency is 500 Hz,the maximum speed of the ISSPA is 2.287 mm/s in the stick-slip mode. When the driving voltage of the piezoelectric stack is 60 V, the frequency is 3 Hz and the load is 0.5 kg,the minimum step displacement is 57 nm in inchworm mode. Demonstration of cell injection is carried out by using the ISSPA to positioning and puncturing a zebrafish embryo. Fast positioning with the stick-slip mode and accurate puncture with the inchworm mode are achieved with the ISSPA alone, taking 12 seconds for the whole injection process. It could be expected to apply the ISSPA to cells with wide range of diameter, as the frequency of the stick-slick mode and the voltage of the inchworm mode could be well regulated.

The problem of drive span maximization in electric vehicle is well studied. There exist number of approaches around the problem which uses residual energy and sleep mode as key in maximizing the drive span. However, they suffer to achieve higher performance in drive span maximization. This article presents a novel Dual Model Photovoltaic Power System Based Drive Span Maximization Model (DPDSM). The model is focused on maximizing the storage of voltage in the PV cells and utilizing maximum battery supply. The model generates the voltage from the photovoltaic system and regulates the power to the electric vehicle. The model has been connected with number of photovoltaic cells, which has been connected in serial. Using them, the required voltage has been regulated to the electric motor. In another mode, the residual voltage of the vehicle battery has been changed to discharge mode which support the regulation of voltage for the vehicle. The dual mode photovoltaic power system regulates effective power for the electric vehicle continuously with less voltage loss.

Existing communication systems require efficient, compact and portable microstrip filters so that it contributes in enhancing the performance of communication system. Existing communication at Sband system requires spurious free signal transmission as well as reduced insertion and return loss, improved bandwidth and sharp roll off rate. The stated parameters could be improved through the design of a compact resonator filter. Hence, in this paper the design, development and characterization of a dual mode close loop resonator filter on microstrip structure at S-band is discussed. The proposed resonator filter design exhibits performance improvement in terms of insertion loss (<1 dB), return loss (Better than 12 dB), Bandwidth (>5%), sharp role off as compared to existing filter. Dual mode operation of close loop resonator filter is explained through the time varying field distribution. The size optimization of the designed resonator filter is accomplished without altering electrical parameter. The designed resonator filter has also been fabricated on two different substrates and comparative analysis has been carried out. Finally the realized filters have been characterised for its suitability in space applications. [ABSTRACT FROM AUTHOR]

In this paper, a new dual mode blind equalization method using neighborhood symbol‐based decision and decision‐directed (NSBD‐DD) algorithm is proposed to equalize the satellite communication signals. The proposed algorithm adopts the combined cost function to employ the advantages of symbol decision algorithm and the decision‐directed algorithm, which can further improve the universality of the proposed algorithm. Compared with the conventional blind equalization algorithm, the compensation ability of intersymbol interference and convergence speed of the proposed algorithm can be improved simultaneously. To verify the performance of the proposed algorithm, the computer simulation is performed, and the simulation results show that the residual intersymbol interference of the 64QAM signals can be decreased to −50 dB under the satellite channel, which has 30 dB lower than multi‐modulus algorithm (MMA), 26 dB lower than NSBD algorithm, and 10 dB lower than SBD algorithm. And compared with SBD algorithm, the number of iterations required for the NSBD‐DD algorithm can be decreased from 8000 iterations to 6000 iterations, which convergence speed is increased by 25%. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In 2020, King's College London introduced HyFlex teaching as a means to supplement online and face-to-face teaching and to respond to Covid-19 restrictions. This enabled teaching to a mixed cohort of students (both online and on campus). This article provides an outline of how such an approach was conceptualized and implemented in a higher-education institution during an intense three-month period over that summer and prior to the limited re-opening of the university campus. This was a new approach that offers a number of pointers for reflection and provides key insights in on this novel learning environment and the physical and pedagogical contexts in which learning can occur. Technical implementation factors are detailed, along with both reflections on challenges and solutions. Pedagogical issues such as cognitive load, social presence, and resolving the issues of a cohort spread across two locations are discussed. While we should be mindful of the limitations of this relatively-specific research, and shouldn't therefore over-extrapolate our findings, one key finding is that delivering Hyflex is associated with a higher cognitive load. Further, the audio quality of our implementation enhanced the feeling of presence in the learning environment. We recommend providing appropriate technical and pedagogical training, as well as audio-visual and digital education support. [ABSTRACT FROM AUTHOR]

In this study, a rapid fluorescent and colorimetric dual-mode detection strategy for Hg2+ in seafoods was developed based on the cyclic binding of the organic fluorescent dye rhodamine 6G hydrazide (R6GH) to Hg2+. The luminescence properties of the fluorescent R6GH probe in different systems were investigated in detail. Based on the UV and fluorescence spectra, it was determined that the R6GH has good fluorescence intensity in acetonitrile and good selective recognition of Hg2+. Under optimal conditions, the R6GH fluorescent probe showed a good linear response to Hg2+ (R2 = 0.9888) in the range of 0–5 μM with a low detection limit of 2.5 × 10−2 μM (S/N = 3). A paper-based sensing strategy based on fluorescence and colorimetric analysis was developed for the visualization and semiquantitative analysis of Hg2+ in seafoods. The LAB values of the paper-based sensor impregnated with the R6GH probe solution showed good linearity (R2 = 0.9875) with Hg2+ concentration in the range of 0–50 μM, which means that the sensing paper can be combined with smart devices to provide reliable and efficient Hg2+ detection. [ABSTRACT FROM AUTHOR]

Mycotoxin contamination in foods and other goods has become a broad issue owing to serious toxicity, tremendous threat to public safety, and terrible loss of resources. Herein, it is necessary to develop simple, sensitive, inexpensive, and rapid platforms for the detection of mycotoxins. Currently, the limitation of instrumental and chemical methods cannot be massively applied in practice. Immunoassays are considered one of the best candidates for toxin detection due to their simplicity, rapidness, and cost‐effectiveness. Especially, the field of dual‐mode immunosensors and corresponding assays is rapidly developing as an advanced and intersected technology. So, this review summarized the types and detection principles of single‐mode immunosensors including optical and electrical immunosensors in recent years, then focused on developing dual‐mode immunosensors including integrated immunosensors and combined immunosensors to detect mycotoxins, as well as the combination of dual‐mode immunosensors with a portable device for point‐of‐care test. The remaining challenges were discussed with the aim of stimulating future development of dual‐mode immunosensors to accelerate the transformation of scientific laboratory technologies into easy‐to‐operate and rapid detection platforms. [ABSTRACT FROM AUTHOR]

Following implementation of a novel Hybrid flexible synchronous teaching approach, research was conducted. This looked at student views and perceptions of the approach both technically and pedagogically. The aim was to gather data to understand the approach from a student perspective and explore what would help ensure they gain the most from their experience in terms of engagement. Focus groups and interviews were held, and coding of data and thematic analysis was conducted. The main findings concerned engagement, equity of experience, and non-standard use issues, as well as benefits around flexibility for students. An original contribution to knowledge in this paper is shown through this being the first example of the thematic analysis of student feedback from hybrid flexible learning in this specific HE context. Limitations of this research include the specific conditions under which the research was conducted during a pandemic as this forced use of online-only recruitment and data gathering. [ABSTRACT FROM AUTHOR]

Copyright of Journal of King Abdulaziz University: Engineering Sciences is the property of King Abdulaziz University, Scientific Publishing Centre and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Study region: Major urban areas in Henan Province of central China. Study focus: data fusion technology is also a key and difficult point in the field of flood research. Remote sensing and text data have different modalities and scales, making fusion difficult. This study proposed a remote sensing and text bimodal data fusion model based on UFCLI, and we validated the spatiotemporal distribution of floods and the calculation results of disaster losses. The results show that through the coupling analysis of remote sensing and text bimodal data, rainstorm and flood events can be fully reproduced in space and time. The proposed UFCLI effectively improves the accuracy of remote sensing single-data inversion for urban flood disaster losses. The flood loss in Henan is 121.98 billion yuan, and the accuracy improvement result is R² increased by 0.08 and MAPE decreased by 0.88. New hydrological insights for the region: In the case of sudden urban storm flooding with complex spatial and temporal evolution, the traditional hydrological-hydraulic model has many pending parameters, which makes it difficult to accurately calculate large-scale disaster losses. By establishing a theoretical model of bimodal data fusion, we effectively use the complementary spatiotemporal information using remote sensing and text to solve the differences in spatiotemporal scales existing between remote sensing and text data. The timeliness and accuracy of urban flood damage estimation have further improved. Data Availability Statement: Not applicable.

According to the application requirements of reconnaissance and jamming integration in the field of electronic countermeasures and the operational requirements of wide and narrow band radar, a dual-mode reconnaissance and jamming integration architecture based on digital transceiver channelization and digital parallel up-down conversion structure is proposed in this paper. The implementation of transceiver based on 50% overlapping channel overlap without blind area is studied; and simulation model is established and is ability to reconstruct wide and narrow band signals is evaluated. On this basis, the strategy and basis of the two modes working together are obtained. Through dual-mode cooperative work, it cannot only measure the parameters of signals with different bandwidth, but also adaptively store digital radio frequency and reconstruct jamming signals with high linearity and low spurious. [ABSTRACT FROM AUTHOR]

A dual‐band scandium‐aluminum nitride (Sc0.28Al0.72N) Lamb‐wave bandpass filter is implemented with intrinsically configurable center frequencies at 628 MHz and 1.07 GHz. The filter is created from electrical coupling of dual‐mode resonators with complementary‐switchable operation states defined by spatial polarization tuning in ferroelectric Sc0.28Al0.72N film. The resonators are created with patterning interdigitated transducers (IDT) on the top surface and exploit the floating bottom electrode for application of low‐frequency polarization switching pulses. Switching polarization direction under consecutive electrode fingers in unified and alternating directions results in excitation of Lamb modes with different wavelengths equal and twice the IDT pitch size, with a frequency ratio of ≈1.70. The intrinsically configurable dual‐band filter shows bandwidths of 11.9 MHz and 10.8 MHz, insertion losses of 2.6 and 2.8 dB, and on‐off switching isolations of 12 and 9 dB, when operating at 628 MHz and 1.07 GHz, respectively. The intrinsic configuration of center frequency, enabled by ferroelectric polarization switching, highlights the potential of dual‐band scandium‐aluminum nitride Lamb‐wave filters for creation of compact multifrequency spectral processors. [ABSTRACT FROM AUTHOR]

Degradation issues are major obstacles to commercializing reversible solid oxide cells (rSOCs), which are promising energy production/storage devices. This article organizes and comprehensively reviews the current understanding of degradation issues in rSOCs, which range from fundamental research on degradation in both single and dual modes to solution strategies for both bifunctional material development and preparation/manufacture optimization, as well as modelling work performed at different scales to predict the degradation behaviours of rSOCs. It proposes perspectives for state-of-the-art work on degradation and solutions highlighted in reversible operation. An in-depth review of the links and differences for degradation in single and dual modes is also emphasized. The trade-offs between various degradation issues for rSOCs must be considered by further understanding the degradation mechanisms in dual-mode operation to improve the reversibility/durability of long-term applications. [ABSTRACT FROM AUTHOR]

Dual-mode electrochemical aptasensor based on nitrogen-doped graphene (NG) doped with the conducting polymer polypyrrole (PPy) nanocomposite is proposed for the determination of acetamiprid. NG/PPy was electrodeposited onto the glassy carbon electrode (GCE) using cyclic voltammetry technique. NG/PPy/GCE showed outstanding electrocatalytic activity for the oxidation of nitrite due to "active region" induced by the charge redistribution of carbon atoms. The ultrasensitive dual-mode biosensor for acetamiprid could be easily developed by coupling acetamiprid aptamers with the NG/PPy hybrid. The specific binding between acetamiprid and the aptamers resulted in the increase of differential pulse voltammetry (DPV) signal change and the decrease of chronoamperometry (CA) signal, and the concentration of acetamiprid could be measured. The working potentials of DPV and CA were − 0.2 ~ 0.4 V and − 0.4 ~ 0.4 V (vs. SCE), respectively. The dual-mode acetamiprid biosensor showed a wide linear range from 10−12 to 10−7 g mL−1, with low detection limits of 1.15 × 10−13 g mL−1 and 7.32 × 10−13 g mL−1 through DPV and CA modes, respectively. Moreover, owing to high active area and superior conductivity, as well as good electrocatalytic ability, the dual-sensing platform based on NG/PPy nanocomposite supported the quantification of acetamiprid in complex samples. A dual-mode electrochemical aptasensor based on NG/PPy nanocomposite for acetamiprid detection was proposed through both the increase of differential pulse voltammetry (DPV) signal change and the decrease of chronoamperometry (CA) signal of the nitrite oxidation electrocatalyzed by NG/PPyn in sensors and biosensors. [ABSTRACT FROM AUTHOR]

We propose a simple and robust biosensing platform which can be used for accurate determination of multiplex microRNA targets in biological samples. We develop the sensor by immobilizing a novel DNA nanomachine system on the surface of a gold-nanoparticles-modified optical fiber, which contains a uniquely designed dual-functional fork-type track chain with a FAM-labeled DNAzyme recognition site on one branch and a rolling-loop-amplification (RCA) primer on the other. The strategy allows two amplification strategies, i.e., DNA walking and RCA, to be easily achieved as the target microRNAs are in the sample to initiate the corresponding reactions. Two different microRNAs (miRNA-21 and miRNA-375 in the study) are independently and accurately determined without interference from each other, by respectively measuring fluorescence and chemiluminescence signals generated from DNA walking and RCA. The results show that the method is capable for multiplex micorRNA assays with high sensitivity (limit-of-detection 0.21 pM for miRNA-21 and 0.018 pM for miRNA-375) and high selectivity, and the sensor exhibits good repeatability and storage stability. The method successfully determines microRNAs in MCF-7, Hela and MCF-10A cells, showing its ability to analyze real complex biological samples. [Display omitted] • A simple and robust biosensing platform with optical fiber as the support for detection of multiplex microRNAs. • A fork-type-track DNA nanomachine to easily achieve dual-mode signal amplification strategies. • Independent dual-readouts of the sensor for dual-target assays without interfering with each other. • Determination of dual microRNAs in human cells with satisfactory accuracy. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nitrogen-doped carbon dots (N-CQDs) with high fluorescence quantum yield were synthesized using a green and simple method. • Two modes of fluorescence emission displacement method and fluorescence internal filtering effect detection method were used to detect quinoline yellow, and their detection limits were 0.18 μM and 2.6 nM respectively. • The constructed fluorescent sensor has high sensitivity and excellent selectivity. • The sensor can actually measure the content of quinoline yellow in common beverages. • A fluorescent test strip was constructed for the visual detection of quinoline yellow. Quinoline yellow (QY), as a food coloring agent, will consume a large number of detoxifying substances in the body after being ingested by the human body, interfering with the normal metabolic functions of the human body, and may cause allergies, diarrhea and other symptoms, as well as a certain degree of carcinogenicity, posing a great threat to human health. As a result, it is critical to develop a fast, sensitive, and effective approach to determining quinoline yellow in food. In this study, carbon dots (N-CQDs) with high fluorescence quantum yield were prepared and used to determine the QY content using the dual mode of internal filtering effect and fluorescence emission shift detection. Both methods showed good linearity in the range of QY concentration of 0.3–3.2 μM, and the detection limits were classified as 2.6 nM and 0.18 μM. In addition, in order to achieve visual detection of QY, fluorescent test strips were constructed using the carbon dots and non-fluorescent qualitative filter paper to make the detection of QY more convenient. This probe presents a novel way for detecting quinoline yellow in food analysis. [ABSTRACT FROM AUTHOR]

Miniaturized dual-band filtering switches are proposed in this article using multimode dielectric resonators (DRs). The planar printed circuit boards (PCBs) are utilized not only to construct the hybrid electromagnetic boundary for quad-mode DR, but also to offer the switchable multimode feeding structures with the p-i-n diodes. When the diodes are reversely biased, all the four modes are excited simultaneously by the mixed electric and magnetic couplings and controlled flexibly to construct the dual-band response. In this manner, extra losses from diodes are avoided, and low-loss transmission is realized. When the diodes are forward biased, all the four modes are shut off at the same time. Owing to the used mixed electric and magnetic couplings, the isolation is enhanced further by the cancellation of the electric and magnetic couplings between the feeding line and the resonant modes. For demonstration, both dual-mode and quad-mode filtering switches with dual-band operations are fabricated and tested. With only one quad-mode DR, high performance, including low-loss dual-band transmission and high-level isolation, is observed in the measurement, making the proposed switches promising in high-standard multiband time division duplex (TDD) systems. [ABSTRACT FROM AUTHOR]

High-selectivity substrate integrated waveguide (SIW) cavity bandpass filter loaded with perturbing elements and resonators are designed for X and Ku band applications. This filter is constructed by combining a perturbing element and two stepped resonators ( R 1 and R 2 ) on either side of the perturbing element into a square SIW cavity for a third-order passband operation. First, the perturbing element-loaded SIW cavity causes different electric field distribution for two modes ( T E 110 and T E 120 ) compared to unloaded SIW cavity modes. The mode shifting of the SIW cavity loaded with and without perturbing elements is explained using eigenmode analysis. Next, the T E 110 mode and T E 120 mode of SIW cavity loaded with perturbing element is coupled using the two stepped resonators inside the cavity. The coexistence of electric and magnetic coupling between the resonators ( R 1 and R 2 ) and the central perturbing element produces three poles that improve the proposed filter’s bandwidth. The generation of three transmission zeros improves the selectivity of the filter to a greater extent. The filter offers a broader bandwidth of 1.76 GHz with a center frequency 11.66 GHz. The fabricated filter uses an RTduroid 5880 substrate of size 18.5 × 18.5 × 0.51 mm 3 . The benefits of the filter are compactness and a more straightforward structure without performance negotiation. The developed filters present approach is validated by fabrication and measurement. [ABSTRACT FROM AUTHOR]

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NaYF4 as the core and NaGdF4 as the outer layer were used to obtain NaYF4:Yb3+/Tm3+@NaYF4:Ce3+/Eu3+ nanoparticles. Physical and morphological investigations indicated that the obtained nanoparticles were prepared in a hexagonal shape, with the NaGdF4 shell layer uniformly encapsulated on the NaYF4 core. Strong Tm3+ upconversion emission peaks were observed for a 980-nm-laser-excited sample, while strong Eu3+ downconversion emission peaks were observed for a 254-nm-laser-excited sample. By zonal doping of Tm3+ and Eu3+, their fluorescence intensity can be significantly increased; more importantly, simultaneous temperature measurements with dual-mode upconversion/downconversion can be achieved. The temperature measurement properties of the dual mode were also investigated, and it was discovered that the upconversion 3F3 → 3H6 and 1G4 → 3F4 thermocouple energy levels gave the best temperature measurements with maximum absolute and relative sensitivities of 0.0877 K–1 and 1.95% K–1, respectively, which are better than the current temperature measurement sensitivities of most rare-earth-based materials. This material was prepared as fiber-optic temperature-sensing probes to detect the temperature in the environment in real time and was found to perform excellently for temperature measurement. [ABSTRACT FROM AUTHOR]

In this article, a dual-mode phase-conjugating/active Van Atta array using an integrated switchless phase-conjugating mixer/reflection amplifier is presented. The proposed array consists of $N$ dual-band mixer/reflection amplifiers (DMRAs), $N$ dual-mode hybrids, and $2N$ dual-band patch antennas. The novel integrated mixer/reflection amplifier comprises a single low-noise GaAs heterojunction field-effect transistor (HJ-FET) transistor with suitable input and output matching networks and identical power supply configuration at both modes. Switchless feature, not requiring external mixers, and improved backscatter communication are the main advantages of this component for the dual-mode retrodirective array design. Furthermore, to verify the proposed mixer/reflection amplifier, a DMRA is designed and fabricated at 3.55 and 5.8 GHz resulting in an acceptable performance in both modes. Meanwhile, the phase-conjugating/active Van Atta array microstrip prototype is fabricated. It is experimentally verified using the monostatic and bistatic radiation characteristics, which clearly shows the capability of the proposed architecture as a multimode retrodirective array. [ABSTRACT FROM AUTHOR]

A 3.3 V mode-switching RF CMOS power amplifier (PA) for WLAN applications is presented, which is integrated into a 55-nm bulk CMOS process. The proposed PA offers both static control and dynamic power control, allowing it to operate efficiently in both low-power and high-power modes. The pure low-power mode is achieved by reducing power cells, which are also used for linearization in high power mode. The low-power mode is achieved by reducing the number of power cells which are also used for linearization in the high-power mode. In the dynamic power control mode, the total AM–AM and AM–PM distortion is effectively compensated for by dynamically controlling the number of power cells and adjusting the matching input. The proposed PA achieves an output P1dB of 27.6 dBm with a PAE of 32.7% and an output P1dB of 17.7 dBm with a PAE of 10% in high-power and low-power modes, respectively. It is measured with an 802.11 n 64-quadrature-amplitude-modulation (MCS7) signal and shows a maximum average power of 19 dBm under an error-vector-magnitude (EVM) of −27 dB.

Following implementation of a novel Hybrid flexible synchronous teaching approach, research was conducted. This looked at student views and perceptions of the approach both technically and pedagogically. The aim was to gather data to understand the approach from a student perspective and explore what would help ensure they gain the most from their experience in terms of engagement. Focus groups and interviews were held, and coding of data and thematic analysis was conducted. The main findings concerned engagement, equity of experience, and non-standard use issues, as well as benefits around flexibility for students. An original contribution to knowledge in this paper is shown through this being the first example of the thematic analysis of student feedback from hybrid flexible learning in this specific HE context. Limitations of this research include the specific conditions under which the research was conducted during a pandemic as this forced use of online-only recruitment and data gathering.

As a common heavy metal contaminant, Cd2+ has adverse effects on food safety and consumer health. It is very important for human health to realize highly sensitive Cd2+ detection methods. The self-powered sensing system based on enzyme biofuel cells (EBFCs) does not need an external power supply, which can simplify the experimental equipment and has great application value in portable detection. Thus, the biosensor is innovatively integrated into the screen-printed electrode to construct a new type of portable sensor suitable for on-site and real-time Cd2+ detection. Hybridization chain reaction (HCR) combined with the Cd2+-dependent deoxyribose (DNAzyme) signal amplification strategy is used to enhance the detection sensitivity while specifically recognizing the Cd2+. Moreover, the self-powered sensor combines with smartphones to realize quantitative Cd2+ detection without other instruments and has the characteristic of Effectively improving the hazard detection technology is essential to ensure food safety. Portability, simplicity, and speed are suitable for real-time Cd2+ detection in the field. The dual mechanism and three quantitative modes combining colorimetric and two electrical signals output modes are adopted to realize the visualization and accurate detection. A series of research results confirm that this strategy is of great significance to strengthen the development of intelligent Cd2+ technology, expand the application of self-powered sensing technology, and improve the safety detection system. • Plug and play self-powered chip facilitates precision heavy metal detection. • Dual mechanism and three quantitative mode for quantitative analysis. • High sensitive detection chip can be used for Cd detection in tea samples. [ABSTRACT FROM AUTHOR]

The development of dual-mode strategies with superior sensitivity and accuracy have garnered increasing attention for researchers in Aflatoxin B1 (AFB1) analysis. Herein, a colorimetric-electrochemiluminescence (ECL) dual-mode biosensor was constructed for onsite and ultrasensitive determination of AFB1. The multi-wall carbon nanotubes (MWCNTs) were integrated with the ZnO metal organic frameworks (MOFs) to accelerate the electron transfer and boost the ECL intensity of g-C 3 N 4 nanoemitters. Through the aptamer-based DNA sandwich assay, the CuO@CuPt nanocomposites were introduced onto the electrode and acted as the dual functional signal nanoprobes. Due to the good spectrum overlap between the CuO@CuPt nanoprobes and g-C 3 N 4 nanosheets, ECL signal could be efficiently quenched. Additionally, the CuO@CuPt nanoprobes show superior catalytic properties towards the TMB and H 2 O 2 colorimetric reactions, and an obvious color alteration from colorless to blue can be observed using the smartphone. Under optimized conditions, a sensitive and accurate dual-mode analysis of the AFB1 was accomplished with the colorimetric detection limit of 3.26 fg/mL and ECL detection limit of 0.971 fg/mL (S/N = 3). This study combines innovative nanomaterial properties of ZnO@MWCNTs, g-C 3 N 4 and CuO@CuPt for ultrasensitive dual-mode detection, which offers new opportunities for the innovative engineering of the dual-mode sensors and demonstrates significant potential in food safety analysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • A three-atom site catalyst of CoFeCu hydroxide nanozyme is rationally prepared. • The CoFeCu nanozyme can mimic the behavior of oxidase by trigging O 2 into O 2 ·−. • The elaborate doping of low content Cu leads to higher catalytic activity and adequate detection sensitivity. • A low-cost POCT monitoring system is designed for on-site analysis of nitrite in food samples. Great progress in nanozyme catalysis for distinct catalytic reactions have been made. However, more current nanozyme-induced sensing platforms are depended on oxidase-like nanozymes with multienzymatic catalytic behavior, which can affect the determination accuracy and reliability. Designing high active and stable advanced nanozymes for enzyme-like catalysis remains a huge challenge for analytic chemistry. Herein, a three-atom site catalyst of CoFeCu hydroxide nanozyme is rationally prepared for constructing sensing platform by utilizing oxidase-like catalytic activity. The CoFeCu nanozyme can mimic the behavior of oxidase by trigging O 2 into O 2 ·− via its highly dispersed metal active sites, which exhibits good oxidase-like activities with of 2.22 mM and of 3.69 × 10−8 M·s−1 toward 3, 3′, 5, 5′-tetramethylbenzidine (TMB). Specifically, the elaborate doping of low content Cu leads to higher catalytic activity and adequate detection sensitivity. Interestingly, with the addition of nitrite, a redox and diazotized reaction can be induced to generate visual color change from blue to yellow, resulting in the nitrite level-related ratio variation for the absorbance intensity at 665 and 450 nm. Besides, to the realize the demand of point-of-care monitor of nitrite, a portable sensor was built containing a dark box by a UV lamp and an intelligent smartphone. In the colorimetry-smartphone modes, the linear ranges of nitrite are 1–290, and 3.3–250 μM, with related detection limits of 0.9, and 2.96 μM, respectively. This strategy was further used to detect nitrite in river water with outstanding results with the dual mode. Therefore, the proposed dual-mode detection approach provides promising potential for self-house monitor of nitrite, which will greatly improve the analysis efficiency and large-scale determination in human life quality. [ABSTRACT FROM AUTHOR]

Dual-mode detection nanotags with non-interference sensing signals had great potential to overcome the limitations of individual sensors, such as narrow monitoring range and inaccurate detection results. Herein, Au-Ag@MnO 2 nanoparticles (NPs) with inherent surface-enhanced Raman spectroscopy (SERS) activity and plasmon-enhanced electroreduction (ER) signals were first reported. 2-mercaptobenzoimidazole-5-carboxylic acid (MBIA) mainly modulated the growth of Ag component and also endowed Au-Ag NPs with intrinsic SERS signals, thereby eliminating the need for additional modifications with SERS reporters. The deposition of MnO 2 shell on Au-Ag NPs weakened the SERS signals but displayed two ER peaks at 0.5 V and 0.1 V, owing to the ER process of Mn4+ and Ag+, respectively. The peak at 0.5 V was amplified 1.23 times under light exciting, owing to the proposed plasmon-enhanced ER principle·H 2 O 2 triggered the conversion of MnO 2 to Mn2+ and exposed the Au-Ag NPs, resulting in "turn on" SERS signals and "turn off" ratiometric electrochemical responses. SERS-active and electroactive Au-Ag@MnO 2 NPs achieved dual-mode detection of uric acid with urate oxidase (UOX) as catalysts. Rationally designed plasmonic metal-semiconductor heterogeneous nanocomposites may generate multiple-mode optical and electrochemical signals for accurate and quantitative detection applications. • Au-Ag@MnO 2 NPs show label-free intrinsic SERS activity. • Au-Ag@MnO 2 NPs exhibit electroreduction peaks at 0.5 V and 0.1 V. • Plasmon-enhanced electroreduction principle of Au-Ag@MnO 2 NPs is proposed. • H 2 O 2 triggers the "turn on" SERS signals and "turn off" ratiometric electroreduction peaks. • Dual-mode sensors are proposed for uric acid detection. [ABSTRACT FROM AUTHOR]

Excessive antibiotic residues increased the environmental damage and safety of animal products, leading to serious health threats. In this study, a dual-mode probe was developed and applied as an electrochemical/fluorescence sensor for tetracycline (TET) detection. The probe, comprising a fluorescent covalent organic framework, electroactive methylene blue, gold nanoparticles (AuNPs) and single-stranded DNA, was synthesized by self-assembly. A glassy carbon electrode was functionalized with molybdenum disulfide nanosheets, AuNPs, and aptamers. The probe exhibited fluorescent signals in solution and electrochemical signals after being specifically connected to the electrode via hybridization. In the presence of TET, the probe is be competitively expelled from the modified electrode, resulting in an increase in the fluorescent signal and a decrease in the electrochemical signal. The developed electrochemical/fluorescence dual-mode sensor enabled sensitive TET detection in the concentration range of 10 nM–10 mM, with minimum detection limits of 0.03 nM (electrochemical) and 0.05 nM (fluorescence). With its high selectivity, superior reproducibility, and excellent stability, the proposed dual-mode sensor demonstrates high reliability, and excellent application prospects for TET detection in milk and river water samples. • An electrochemical/fluorescent dual-mode probe based on covalent organic framework. • Opposite signals of fluorescent on and electrochemical off for tetracycline detection. • Electrode conductivity was improved by AuNPs@MoS 2 NS. • Constructed biosensor showed good performance for tetracycline detection. [ABSTRACT FROM AUTHOR]

Developing ultrasensitive sensing platforms for trace ochratoxin A (OTA) in food safety is still challenging. Herein, we presented a novel dual-mode sensing strategy for fluorescence and colorimetric detection of OTA by combining the target-responsive hemin-encapsulated and copper nanoclusters (CuNCs) functionalized DNA hydrogel. Through simple assembly and in situ synthesis methods, fluorescence CuNCs are synthesized and modified on the 3D hydrophilic network structure of DNA cross-linked. OTA specifically recognized by Apt-linker can control the collapse of hydrogel, resulting in the fluorescence quenching of CuNCs and release of coated hemin. Interestingly, OTA could trigger Apt-linker conformational changes to form G-quadruplex structures, allowing the released hemin to form G-quadruplex/hemin DNAzyme via self-assembly. Fluorescence signal amplification could be achieved through further fluorescence quenching of CuNCs caused by DNAzyme-catalyzed hydrogen peroxide (H 2 O 2) because of the peroxidase activity of DNAzyme. Simultaneously, DNAzyme could catalyze the H 2 O 2 -mediated oxidation of TMB to provide colorimetric signal. Thereafter, the DNA-CuNCs hydrogel exhibited low detection limits of 3.49 pg/mL in fluorescence mode and 0.25 ng/mL in colorimetric modality. Real sample analyses of foodstuffs showed satisfactory results, providing prospective potential for monitoring mycotoxin contaminant. [Display omitted] • CuNCs were in-situ synthesized on 3D hemin-laden DNA hydrogel network framework. • Novel dual-mode aptasensor based the OTA-responsive DNA-CuNCs hydrogel was designed. • Self-assembly G-quadruplex/hemin DNAzyme greatly improved the sensitivity for OTA sensing. • The assay showed good reliability for on-site monitoring of mycotoxins in real samples. [ABSTRACT FROM AUTHOR]

In this study, a rapid fluorescent and colorimetric dual-mode detection strategy for Hg2+ in seafoods was developed based on the cyclic binding of the organic fluorescent dye rhodamine 6G hydrazide (R6GH) to Hg2+. The luminescence properties of the fluorescent R6GH probe in different systems were investigated in detail. Based on the UV and fluorescence spectra, it was determined that the R6GH has good fluorescence intensity in acetonitrile and good selective recognition of Hg2+. Under optimal conditions, the R6GH fluorescent probe showed a good linear response to Hg2+ (R2 = 0.9888) in the range of 0–5 μM with a low detection limit of 2.5 × 10−2 μM (S/N = 3). A paper-based sensing strategy based on fluorescence and colorimetric analysis was developed for the visualization and semiquantitative analysis of Hg2+ in seafoods. The LAB values of the paper-based sensor impregnated with the R6GH probe solution showed good linearity (R2 = 0.9875) with Hg2+ concentration in the range of 0–50 μM, which means that the sensing paper can be combined with smart devices to provide reliable and efficient Hg2+ detection.

A one‐port surface acoustic wave (SAW) resonator based on Co40–Fe40–B20/SiO2/ZnO/quartz multilayer structure and exhibiting a dual mode, Rayleigh and Love wave modes, is investigated to achieve a multifunctional sensor measuring both temperatures and magnetic fields. The Rayleigh wave mode of the resonator is used for temperature measurement with a temperature sensitivity of −37.9 ppm/°C, and the Love wave mode is used for magnetic field measurement. Co40‐Fe40‐B20 is the magnetic sensitive layer, and quartz crystal is the piezoelectric substrate. ZnO film is also a piezoelectric but considered here in combination with SiO2 as insulating layers and serves to control impedance matching and temperature dependence of the sensor. ZnO and SiO2 thicknesses are selected to realize temperature compensation for the Love wave mode and making this mode highly sensitive to magnetic fields and insensitive to temperatures. The magnetic field sensitivities of −170.4 kHz m−1 T−1 and −621.6 kHz m−1 T−1 are obtained respectively for the fundamental and the third harmonic of the Love wave mode. The proposed structure is beneficial to design reliable hybrid SAW magnetic field and temperature sensors. [ABSTRACT FROM AUTHOR]

This paper focuses on introducing a transformerless DC/DC converter with low total switching device power in dual working modes including step-up and step-up/down modes. The proposed converter is analysed in terms of the continuous conduction mode, steady state, and efficiency with the replacement of parasitic resistance effects. The proposed converter in the step-up mode has a high voltage gain ratio and a continuous input current. Then, the other working mode of the proposed converter with relevant DC/DC converters is compared. By this comparison, the proposed converter has a high voltage gain ratio. Also, the converter characteristics such as voltage stress on power switches and charge pump capacitors are in a good condition in this mode. Finally, the experimental results from a laboratory made prototype and the obtained waveforms from the simulation in PLECS are presented for validation such as higher voltage gain ratio, lower total switching device power and better efficiency. [ABSTRACT FROM AUTHOR]

A novel wearable cavity-backed slot repeater antenna is presented to improve the link between implant antennas and the outside world. This proposed repeater antenna consists of two slots on opposite sides of a shallow rectangular cavity. These slots are activated in an alternating way, selecting the mode of operation: in-body or off-body. Through the antenna’s in-body mode, signals transmitted by the implant antenna are received and conveyed to the off-body gateway via its off-body mode. Both modes are designed to operate in the 2.4 GHz industrial, scientific, and medical (ISM) Band. The antenna is fed by a single diagonal stripline, and the two slots encounter the stripline at the same location with impedance matching obtained through offset feeding. The antenna has an overall size of 33.5 mm $\times 37$ mm $\times 3.14$ mm and has been shown to perform well near numerical and physical phantoms, communicating with deep tissue implants with an outstanding maximum $|{S_{21}}|$ value of −37.4 dB measured at 6 cm depth. [ABSTRACT FROM AUTHOR]

The integration of terrestrial and satellite communications (Satcom) is advocated for satisfying the challenging requirements of seamless, high-performance services. However, both the bandwidth and the power available are limited over satellite channels. In this paper, we propose index modulation (IM) and code-aided Satcom by conveying information by a pair of distinguishable constellation modes and their permutations. In order to combat both the linear and nonlinear distortion imposed by satellite channels, we conceive a factor graph (FG)-based iterative detection algorithm for Satcom relying on dual-mode (DM) IM (Sat-DMIM). The correlation amongst Sat-DMIM symbols imposed by both the channel-induced dispersion and the mode-selection mapping is explicitly represented by the FG constructed. Then the amalgamated belief propagation (BP) and mean field (MF) message passing algorithm is derived over this FG for detecting both the IM bits and the classic constellation mapping bits, while eliminating both the linear and nonlinear distortions. The complexity of the iterative detection algorithm is reduced by linearizing some high-order terms appearing in nonlinear distortion components using the a posteriori estimates of the Sat-DMIM symbols obtained from the previous iteration. Our simulation results demonstrate the power of the proposed amalgamated BP-MF-based and partial linearization approximation-based iterative detection algorithms. [ABSTRACT FROM AUTHOR]