Carrier Transmission Research Articles

Modeling and Fabrication of a Reconfigurable RF Output Stage for Nanosatellite Communication Subsystems

Current small satellite platforms such as CubeSats require robust and versatile communication subsystems that allow the reconfiguration of the critical operating parameters such as carrier frequency, transmission power, bandwidth, or filter roll-off factor. A reconfigurable Analog Back-End for the space segment of a satellite communication subsystem is presented in this work. This prototype is implemented on a 9.5 cm2 6-layer PCB, and it operates from 0.070 to 6 GHz and complies with CubeSat and IPC-2221 standards. The processing, control, and synchronizing stages are carried out on a Software-Defined Radio approach executed on a baseband processor. Results showed that the signal power at the output of the proposed Analog Back-End is suitable for feeding the following antenna subsystem. Furthermore, the emitted radiation levels by the transmission lines do not generate electromagnetic interference.

Preparation and photoelectric properties of the polycrystalline silicon solar cells depositing Sb

Sb2Ox nano-film/c-Si composite solar cells were prepared by the spin-coating method. The absorption efficiency, the minority carrier lifetime, and the internal/external quantum efficiency of Sb2Ox/c-Si solar cells had a significant improvement because Sb2Ox nano-film, as a wide band gap (~3.44 eV) semiconductor, had an excellent photoelectrical performance, and could form an effective heterojunction with the silicon substrate. Sb2Ox nano-films deposited on the c-Si wafers reduced the loss of the solar light, absorbed the high-energy photons, accelerated the transmission and separation of the photo-generated carriers, and suppressed the recombination of the minority carriers effectively. Thus the power conversion efficiency was improved from 12.8 to 15.3% in Sb2Ox/c-Si solar cells, which was enhanced by 19.53% compared to the untreated polycrystalline silicon solar cells.

Optimization of the Carrier Recombination and Transmission Properties in Perovskite Leds by Doping Poly (4-Vinylpyridine) and Graphene Quantum Dots Made of Chitin

Optimization of the Carrier Recombination and Transmission Properties in Perovskite Leds by Doping Poly (4-Vinylpyridine) and Graphene Quantum Dots Made of Chitin

Cumulative effects of doping on Sn3O4 structure and electrode performance for rechargeable sodium-ion batteries

Interconnected nanoflakes of modified Sn3O4 are capable of providing fast carrier transmission dynamics and outstanding structural integrity, suggesting the feasibility of the current framework for sodium-ion storage.

Training Deep Filters for Physical-Layer Frame Synchronization

In this paper we demonstrate the application of Fully Convolutional Neural Network (FCN) for Frame Synchronization (FS) in bursty single carrier transmissions, commonly used in wireless sensor networks and Internet of Things (IoT) applications. Our approach shows greatly improved performance compared to noncoherent correlation-based methods under carrier phase and frequency offsets, especially for shorter preambles. Using a fully convolutional architecture allows the training of a deep filter, which we believe is more suited to signal processing tasks than more commonly used deep learning architectures with fully connected layers. In terms of deployment within a wider communications system, it could be treated similarly to a typical signal processing filter, which means it can be deployed to inputs of arbitrary length. Additionally, because the proposed model is composed only of convolutional layers, the entire model benefits from the weight sharing property of convolutional filters, and results in a greatly reduced memory footprint compared to that of similar models containing fully connected layers.

A model exploration of carrier and movement transmission as potential explanatory causes for the persistence of foot-and-mouth disease in endemic regions.

Foot-and-mouth disease (FMD) is a virulent and economically important disease of livestock, still endemic in many areas of Asia and sub-Saharan Africa. Transmission from persistently infected livestock, also known as carriers, has been proposed as a mechanism to support the persistence of FMD in endemic regions. However, whether carrier livestock can infect susceptible animals is controversial; recovered virus is infectious and there are claims of field transmission, but it remains undemonstrated experimentally. Alternate hypotheses for persistence include the movement of livestock within and between regions, and fomite contamination of the environment. Using a stochastic compartmental ordinary differential equation (ODE) model, we investigate the minimum rates of carrier transmission necessary to contribute to the maintenance of FMD in a region, and compare this to the alternate mechanism of persistence through cattle shipments. We find that carrier transmission can theoretically support persistence even at transmission rates much lower than the highest realistic rates previously proposed, and that the parameters with the most effect on the feasibility of carrier-mediated persistence are the average duration of both the carrier phase and natural immunity. However, shipment-mediated persistence remains a viable alternate mechanism for persistence without carrier transmission.

Constructing a novel multi-hierarchical TiO2/g-C3N4/Ag-AgBr photocatalyst with dual Z-scheme heterojunction utilizing Ag as the charge transfer mediator

Constructing multi-heterojunction photocatalysts with multi-sources for carrier generation and with multi-channels for carrier transmission is one of the effective methods for enhancing the photocatalytic activity. Here, a novel TiO2/g-C3N4/Ag-AgBr (TCNAAB) multi-heterojunction photocatalyst was successfully constructed by depositing Ag-AgBr nanoparticles onto 3D spherical TiO2/g-C3N4. With the optimal ratio of TiO2, g-C3N4 and Ag-AgBr, the TCNAAB-50 composite had the highest H2 evolution activity and generated 940.5 μmol g−1 of H2, which was 8.24 times and 2.72 times higher than that generated by single TiO2 and binary TiO2/g-C3N4, respectively. Meanwhile, TCNAAB-50 also exhibited the highest photocatalytic activity toward methyl orange (MO) with the degradation efficiency of 77.6% under LED light. The enhanced photocatalytic performance is attributed to the multi-sources for carrier generation and the multi-channels for carrier transmission of the constructed multi-heterojunction, which help to effectively enhance the light absorption efficiency and the carrier separation and transmission. Based upon PL spectra, photoelectrochemical properties, radical quenching experiments and electron spin resonance spectra, a novel double Z-scheme heterojunction bridged by silver was proposed. The design of high-efficiency multi-heterojunction with multi-carrier excitation sources and multi-carrier transmission channels can be employed in improving the photocatalytic activity of single or binary component photocatalysts.

Fabrication Strategies and Optoelectronic Applications of Perovskite Heterostructures

AbstractMetal halide perovskites (MHPs) are emerging low‐cost and multifunctional semiconductor materials. They have been widely used in optoelectronic devices such as perovskite solar cells, light‐emitting diodes, photodetectors, memristors, and lasers. Developing new MHPs, defects passivation, optimizing device structures, and packaging techniques are all effective methods to improve photoelectric performance and stability of perovskite devices. Particularly, the fabrication of perovskite/perovskite heterostructures (PPHSs) is a novel and arresting method to obtain stable and high‐performing optoelectronic perovskite devices since it can passivate defects, regulate energy gaps, and provide new carrier transmission modes of MHPs for multiple semiconductor applications. In this paper, representative fabrication strategies of PPHSs including films and single‐crystal heterostructures are reviewed, and their applications in optoelectronic devices are summarized. Furthermore, the challenges and prospects of PPHSs are discussed based on the current status.

Efficient solar-driven CO2 reduction on aminated 2D/2D BiOBr/CdS-diethylenetriamine S-scheme heterojunction

In recent years, converting solar energy into chemical energy has been shown to be a promising method to alleviate the problem of a global energy shortage. Coupling different semiconductors to construct a step-scheme (S-scheme) heterojunction photocatalyst has become one of the most effective methods. Through the amination of CdS, a 2D/2D BiOBr/CdS-diethylenetriamine (B/CS-D) S-scheme heterojunction was constructed to achieve efficient charge carrier separation and transfer. It is worth noting that the optimal B/CS-D photocatalyst, with the BiOBr mass ratio of 40%, shows a CO production rate of 19.4 μmol h−1g−1, which is 3.68 times higher than that of CdS-D. The rate of 40%B/CS without D is 11.2 μmol h−1g−1, and the catalyst becomes severely corroded, however, by constructing an S-scheme heterojunction containing D, the stability of the photocatalyst can be improved due to the existence of amine molecules which strengthen the interface contact, and the 2D structure, which increases the area of the contact, thereby speeding up the separation and transmission of carriers. This study shows the construction of an S-scheme heterostructure photocatalyst with improved separation of photoexcited holes and electrons, and a retardation of the corrosion of CdS.

The unique TiO2(B)/BiOCl0.7I0.3-P Z-scheme heterojunction effectively degrades and mineralizes the herbicide fomesafen

A Z-scheme heterojunction photocatalyst (TiO2(B)/BiOCl0.7I0.3-P) was constructed (B: bronze phase; BiOCl0.7I0.3: a solid solution of BiOCl and BiOI in a molar ratio of 7:3; P: polyvinylpyrrolidone). The open channels parallel to the b-axis between the axial oxygen atoms in the bronze TiO2, the unique layered structure of BiOCl and the excellent light absorption characteristics of BiOI create excellent conditions for the absorption and utilization of light, the separation and transmission of photo-generated carriers in the photocatalytic process. TiO2(B)/BiOCl0.7I0.3-P can almost completely degrade and mineralize fomesafen within 20 min, and the environmental toxicity of the degradation products is significantly reduced. Combined with high-resolution mass spectrometry, the degradation pathway of fomesafen was proposed. In addition, TiO2(B)/BiOCl0.7I0.3-P can also quickly and effectively degrade phenol and acetaminophen, indicating that it has good universality. To eliminate the harm caused by various herbicides to the ecological environment, photocatalytic technology will play an increasingly important role.

Structure of the manure resistome and the associated mobilome for assessing the risk of antimicrobial resistance transmission to crops

In this study, the impact of bovine and poultry manure on the quantitative and qualitative composition of antibiotic resistance genes (ARGs) and the environmental mobilome associated with antimicrobial resistance in soil and crops was determined with the use of next generation sequencing methods. The aim of the study was to perform a metagenomic analysis of manure to estimate the risk of the transmission of ARGs and bacterial drug resistance carriers to fertilized soil and crops. The total copy number of ARGs was nearly four times higher in poultry manure (555 ppm) than in bovine manure (140 ppm), and this relationship was also noted in fertilized soil. Poultry manure induced a much greater increase in the concentrations of ARGs in the soil environment (196.4 ppm) than bovine manure (137.8 ppm) immediately after supplementation. The application of poultry manure led to the highest increase in the abundance of genes encoding resistance to tetracyclines (9%), aminoglycosides (3.5%), sulfonamides (3%), bacitracin (2%), chloramphenicol (2%), and macrolide-lincosamide-streptogramin antibiotics (1%). Heavy metals were stronger promoters of antibiotic resistance in the environment than antibiotics. Antibiotics exerted a greater influence on maintaining the diversity of ARGs than on increasing their abundance in soil. Large quantities of insertion sequences (IS), including those associated with the mobility of ARGs in the population of ESKAPEE pathogens, are introduced to soil with manure. These IS remain stable for up to several months, which indicates that manure, in particular poultry manure, significantly increases the risk of rapid ARG transfer to the environment. Manure also largely contributes to an increase in the diversity of the resistome and mobilome in the metagenome of bacteria isolated from crops. Bacteria of the phylum Proteobacteria appear to play a major role in the transmission of multiple ARGs in crops grown for human and animal consumption.

Fabrication of closed-space sublimation Sb2(S1-xSex)3 thin-film based on a single mixed powder source for photovoltaic application

Because of favourable stability, facile fabrication, non-toxicity, tunable bandgap and high extinction coefficient, Sb 2 (S 1-x Se x ) 3 combined the advantages of Sb 2 S 3 and Sb 2 Se 3 have attracted extensive attention. Unlike previous studies using a preformed target or source of a single composition, our study offered a high‐throughput closed-space sublimation method based on a single mixed powder source of Sb 2 S 3 and Sb 2 Se 3 . We fabricated single-phase and highly crystalline Sb 2 (S 1-x Se x ) 3 films with strong (221) orientation, which is beneficial for the rapid transmission of photon-generated carriers. The bandgap of films evolved from 1.79 eV to 1.38 eV that accompany the varying x value of Se content from 0.14 to 0.85. The corresponding solar cells with the structure of FTO/CdS/Sb 2 (S 1-x Se x ) 3 /Au were fabricated, and then the relationship between performance, source temperature and alloy composition were investigated. The open-circuit voltage and short circuit current density showed opposite trends with increased Se content. Finally, the champion device with a PCE of 2.70% was obtained employing Sb 2 (S 0.25 Se 0.75 ) 3 absorber, which had optimal grain orientation, favourable surface morphology. The bandgap is 1.45 eV, which falls into the ideal bandgap in the Shockley–Queisser limit. A low reverse saturation current density (2.35 × 10 −5 mA/cm 2 ) and the relevant diode ideality factor (1.38) were obtained, which implies favourable junction quality. The CSS technique is expected to improve production efficiency and promote Sb 2 (S 1-x Se x ) 3 solar cell commercial applications, worth further optimization.

Extra electric field-enhanced lightning rod effect in pine needle-like Au microarrays for boosting direct plasmon-driven photoelectrochemical hydrogenation reactions via in-situ SERS monitoring

Based on plasmonic metallic nanomaterials (NMs) with unique local surface plasmon resonance (LSPR), the photo-excited hot carrier-driven hydrogenation reaction becomes a new family of photocatalytic transformations in recent years. However, the high work function and rapid hot-carrier recombination of plasmonic NMs create huge barriers for widespread practical application. Herein, we propose a fascinating reactor of up-regulated electrochemical LSPR (EC-LSPR) driven hydrogenation reaction via the construction of hierarchical Au pine needles (H-Au PNs) with enhanced lightning rod effect under appropriate extra electric field. The plentiful elongated Au branches with sharp corners and edges can be served as excellent electron-transport channels for facilitating photo-excited hot carrier transmission and accelerating hot electron collection at nano-tips after plasmon decay. Additionally, the extra electric field with the applied voltage of − 0.8 V further improves the surface charge density and the internal polarization of H-Au PNs, boosting the separation efficiency of hot carriers as well as reducing the photoelectrochemical (PEC) potential on H-Au PNs. It directly leads to an effective activation enthalpy reduction to reach above the energy threshold of water splitting, which can achieve the direct plasmon-driven PEC-hydrogenation conversion of 4-nitrothiophenol (4-NTP) to 4-aminothiophenol (4-ATP) in aqueous solution, and the conversion rate constant is about 5 times higher than bare EC-driven conversion. The present work provides a new opportunity for the emerging direct plasmon-driven hydrogenation reaction.

Integrated Full‐Spectrum Solar Energy Catalysis for Zero‐Emission Ethylene Production from Bioethanol

AbstractEthylene, a hydrocarbon (C2H4), is one of the widely used products in the chemical industry. A traditional dehydration method of ethanol to ethylene relies strongly on high‐temperature and high‐pressure process with significant energy consumption. In this regard, producing ethylene from bioethanol through dehydration is a promising and sustainable approach, but, this process under mild conditions results in low yields and poor selectivity. Herein, an integrated solar energy catalytic system driven by only sun energy under ambient conditions is established for the first time for bioethanol dehydration using oxygen‐vacancy‐abundant (Ov) WO3 coupled with a thin layer of carbon coating (CL) (WO3−x@C). A record‐high ethylene selectivity of 98.1% is achieved driven by full solar spectrum without any external power, featuring zero pollution emission nature. In this process, Ov acts as a solid acid center, which is the key to initiate the dehydration of ethanol to ethylene via a solar thermal process, while the CL promotes solar thermal synergy, ensuring the high reaction temperature and hot carriers transmission simultaneously. In‐situ infrared spectroscopy and thermodynamic calculations demonstrate a novel proton hydrogen‐mediated catalytic process over WO3−x@C. This work provides a new opportunity of using full‐spectrum solar energy for catalytic generation of value‐added chemicals.

One-pot soft integration fabrication of graphene-induced phase transition to form dimension control contact In2S3/G heterojunction hybrids for enhancing visible photocatalytic purification performances

We report the synthesis of a series of graphene-induced self-assembly phase transformations of tetragonal β-In2S3 into cubic α-In2S3 at lower temperatures based on the principles of molecular and crystal engineering and a simple one-pot soft integration strategy based on wet chemistry. Controlled contact In2S3/G heterojunction hybrids with sizes ranging from 3D/2D to 2D/2D. In the process, the 3D petal-like In2S3 is transformed into 2D nanosheets grown on the 2D graphene "mat". Due to effective charge separation and close interfacial contact, the excellent visible catalytic purification performance for the degradation of organic pollutants, benzyl alcohol selective oxidation and reduction of Cr2O72- has been achieved. The significantly improved photocatalytic purification efficiency is mainly due to the graphene-induced phase transition which increases the number of active sites and strengthens the two-dimensional/two-dimensional contact of the interface, which promotes the effective transmission and separation of photo-excited carriers, thereby Effectively improve the photocatalytic purification ability. This research provides new insights for the preparation of high-efficiency graphene-based nano-hybrid photocatalysts with controllable structure through rational use of the structure-oriented and induced phase transition effects of graphene, and expands its visible light catalytic purification applications.

Anion regulation engineering for efficient Ruddlesden-Popper inverted perovskite solar cells

Recently, many studies have focused on exploiting new spacer cations to boost the power conversion efficiency (PCE) of Quasi-two-dimensional (Q-2D) Ruddlesden-Popper (RP) perovskites solar cells (PSCs). As another essential part of RP perovskite structure, halogen anions have a substantial impact on crystalline quality. However, there are few studies about how halogen anions affect RP PSCs and their possible underlying mechanisms. Here, we investigate different halide anions that impact the optoelectronic properties of RP perovskite films. Specifically, we use PEAI, PEABr, and PEACl (PEA = phenethylammonium) to fabricate RP perovskite films based on PEA 2 MA 3 Pb 4 I 11 X 2 (X = I, Br or Cl, n = 4) for systematical study. Through a series of characterizations and analyses, RP perovskite films with PEACl show a higher proportion of vertical crystal orientation and fewer trap-states, which leads to improved carrier transmission pathways. As a result, the devices based on PEACl (PEA 2 MA 3 Pb 4 I 11 Cl 2 , n = 4) achieve a champion PCE of 12.02%, which is higher than PEAI (6.76%, PEA 2 MA 3 Pb 4 I 13 , n = 4) and PEABr (4.26%, PEA 2 MA 3 Pb 4 I 11 Br 2 , n = 4). • The effect of halogen anions on 2D PSCs is systematically investigated. • The Cl − contributes to the vertical orientation of 2D perovskite film. • The Br − impairs the crystallization quality in 2D perovskite film. • RP PSCs based on PEA 2 MA 3 Pb 4 I 11 Cl 2 achieves a champion PCE of 12.02%. • PSCs of PEA 2 MA 3 Pb 4 I 11 Cl 2 retains 97.1% of its initial PCE after 500 h.

Solar-light elimination of various dye effluents using plasmon AgBrCl solid solution on carbon defects-MWCNTs modified with DBD-plasma: Nano-hybrid photocatalyst and ultrasonic precipitation design

AgBr0.75Cl0.25 solid solution on carbon defects-MWCNTs, modifying with DBD-plasma, was fabricated via the sono-precipitation method, employing to degrade dye pollutants under simulated sunlight. XRD, FTIR, Raman, BET-BJH, FESEM, TEM, DRS and PL analyses were applied to characterize the nanophotocatalyst. Results illustrated the improvement of band gap (2.19 eV), existence of SPR property, reducing the recombination rate, improving the separation and transmission of charge carriers, and increasing the access to active sites as a result of the formation of AgBr0.75Cl0.25 solid solution over carbon defects-MWCNTs. Besides, existing MWCNTs along with carbon defects as a result of using DBD-plasma, in AgBrCl/CNT(PT)(1%) structure led to well dispersion, decreasing agglomeration, smaller particles, formation of hydroxyl, epoxy and carboxyl groups on the surface and stronger bonding, trapping of excitons, increasing separation of them, and increasing the access to active sites. So that, the excellent photocatalytic performance was obtained over AgBrCl/CNT(PT)(1%) for the degradation of 50 mg/L crystal violet (87.5%), rhodamine B (95.6%) and methyl orange (81.9%) during 180 min. Reusability was investigated in four cycles; and a reaction mechanism for the photodegradation was suggested.

Multivariable predictive functional control of a compound power-split hybrid electric vehicle

The Corun hybrid system (CHS) is a deeply coupled multiple-input–multiple-output (MIMO) hybrid system. The two inputs are the torques of the two motors. The two outputs are the carrier speed and transmission output torque. Using the traditional control method, the multi-objective control quality cannot be guaranteed because of the adopted static decoupling method and proportional–integral–derivative (PID) controllers. In this paper, the problems of the traditional control method are carefully analyzed, and a new control method is proposed. Instead of static decoupling, dynamic decoupling is adopted to improve the decoupling control effect. A predictive functional controller instead of a PID controller is adopted to deal with the pure delay caused by controller area network (CAN) communication. The tracking effect of the target value is further improved by predictive functional controllers. For the two decoupled subsystems, that is, the integral system and the second-order underdamped system, two predictive functional controllers are designed. The new control method was verified by simulations and tests. The results show that the new control method is superior to the traditional control method for CHS.

Resonant transmission of fermionic carriers: Comparison between solid-state physics and quantum optics approaches

We revisit the phenomenon of the resonant transmission of fermionic carriers through a quantum device connected to two contacts with different chemical potentials. We show that, besides the traditional Landauer-B\"uttiker approach in solid-state physics, this phenomenon can also be described by the non-Markovian master equation for the reduced density matrix of the fermions in the quantum device. We identify validity regions for both approaches in the system parameter space and argue that for large relaxation rates the accuracy of the latter approach greatly exceeds the accuracy of the former.

Preparation of InN films at different substrate temperatures and the effect of operating temperatures on the carrier transmission characteristics of p-NiO/n-InN heterojunction

The good properties of ITO substrate endow the as-grown InN thin films especially attractive for various optoelectronic applications. Herein, the InN thin films were prepared on the ITO substrates by magnetron sputtering. The effects of substrate temperature (Ts) on the structural, morphological, and optical properties of InN films were assessed by X-ray diffractometer, scanning electron microscope and ultraviolet–visible spectrophotometer. The combination of structural and morphological investigation suggested that the better InN thin film was obtained at 200 °C. Then, the variation of the optical band gap and transmittance with Ts was discussed. What's more, the p-NiO/n-InN heterojunction was trial-produced, and the carrier transport characteristics were studied in the range of 30–120 °C. The heterojunction exhibited excellent I–V characteristics at all operating temperatures. This work enriches the description of InN materials and devices, and provides a useful reference for the practical application of InN.