Selective Transmission Research Articles

Gating Effects for Ion Transport in Three-Dimensional Functionalized Covalent Organic Frameworks.

The development of bioinspired nano/subnano-sized (<2 nm) ion channels is still considered a great challenge due to the difficulty in precisely controlling pore's internal structure and chemistry. Herein, for the first time, we report that three-dimensional functionalized covalent organic frameworks (COFs) can act as an effective nanofluidic platform for intelligent modulation of the ion transport. By strategic attachment of 12-crown-4 groups to the monomers as ion-driver door locks, we demonstrate that gating effects of functionalized COFs can be activated by lithium ions. The obtained materials exhibit an outstanding selective ion transmission performance with a high gating ratio (up to 23.6 for JUC-590), which is among the highest values in metal ion-activated solid-state nanochannels reported so far. Furthermore, JUC-590 offers high tunability, selectivity, and recyclability of ion transport proved by the experimental and simulated studies.

Gating Effects for Ion Transport in Three‐Dimensional Functionalized Covalent Organic Frameworks

AbstractThe development of bioinspired nano/subnano‐sized (&lt;2 nm) ion channels is still considered a great challenge due to the difficulty in precisely controlling pore's internal structure and chemistry. Herein, for the first time, we report that three‐dimensional functionalized covalent organic frameworks (COFs) can act as an effective nanofluidic platform for intelligent modulation of the ion transport. By strategic attachment of 12‐crown‐4 groups to the monomers as ion‐driver door locks, we demonstrate that gating effects of functionalized COFs can be activated by lithium ions. The obtained materials exhibit an outstanding selective ion transmission performance with a high gating ratio (up to 23.6 for JUC‐590), which is among the highest values in metal ion‐activated solid‐state nanochannels reported so far. Furthermore, JUC‐590 offers high tunability, selectivity, and recyclability of ion transport proved by the experimental and simulated studies.

A Broadband Low-Profile Transmitarray Antenna by Using Differentially Driven Transmission Polarizer With True-Time Delay

A broadband low-profile folded transmitarray (FTA) is proposed and investigated, in which a novel wideband transmission polarizer (TP) is used to realize low-profile design. The proposed TP, mainly consisting of a differential-fed grid-slotted patch antenna, can realize high-efficiency transmission and polarization selection simultaneously within a wideband frequency range. Moreover, the proposed TP can realize linear transmission phase because of the true-time delay (TTD) technique. Owing to the function of polarization selection and linear transmission phase, the TP can be used as antenna element for a FTA. A 140-element FTA is designed and fabricated by combining the TP with a broadband polarization rotation reflecting surface (PRRS). The measured radiation patterns agree well with the simulated results, and a peak gain of 24 dBi and maximum aperture efficiency of 44.7% are achieved. Furthermore, −1 and −3 dB gain bandwidth with 25.9% and 33.3% are also experimentally demonstrated in the proposed FTA, respectively.

A Miniaturized Frequency Selective Rasorber With Independently Regulated Selective Dual-Transmission Response

In this letter, a miniaturized-element dual-polarized frequency selective rasorber (FSR) with independently regulated dual-transmission response has been presented. The proposed FSR is made of two cascaded layers separated by an air spacer, where the top lossy layer provides wideband absorption along with in-band transmission and the bottom lossless layer exhibits a dual bandpass filter. The novelty of the proposed design lies in the use of lumped capacitors in the top layer to realize the independently controlled highly selective transmission frequencies as well as attain a miniaturized unit cell topology (having dimensions of 0.08 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> × 0.08 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> , λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> being the lowest operating frequency). In addition, convoluted slot geometries are patterned in the bottom layer to obtain the transmission bands appearing at the same frequencies as that of the top layer. The proposed structure has an operating range of 1.87–7.97 GHz, whereas two distinct transmission responses are located at 3.52 and 5 GHz having insertion losses of 1.2 and 0.82 dB, respectively. Furthermore, the geometry exhibits an angularly stable performance upto 40° for both TE and TM polarizations. A prototype of the proposed FSR was fabricated and measured to validate the simulated responses under normal incidence.

A Review of UltraHigh Frequency Ultrasonic Transducers

The ultrahigh-frequency (UHF) ultrasonic transducers are active in various fields, including nondestructive evaluation in the semiconductor industry, microscopic biological organization imaging in biomedicine, particle manipulation, and so on. In these fields ultrahigh-frequency (UHF) ultrasonic transducers play a critical role in the performance of related equipment. This article will focus on the topic of ultrahigh-frequency ultrasonic transducers’ preparation, and reviews three aspects: material selection, focus design, and acoustic energy transmission matching. Provides a summary of the current research status, and puts forward some views on the future development of UHF ultrasound devices.

COLOUR TERMS IN INORGANIC CHEMISTRY: A CORPUS STUDY

Colour is a common physical phenomenon involving selective absorption, reflection or transmission of certain wavelengths of light. It is one of the fundamental properties of chemical compounds, which is particularly evident in the field of inorganic chemistry. The aim of this paper is to present colour terms used by scientists in the field of inorganic chemistry. We concentrate both on basic and non-basic colour terms – as understood by Berlin and Kay (1969). The research material is extracted from a corpus compiled with AntConc, consisting of abstracts published in Inorganic Chimica Acta, Inorganic Chemistry Communications, Journal of Inorganic Biochemistry and ten other chemical journals. The size of the corpus is 1,626,380 words. The most frequent basic colour terms found in the abstracts are blue (370 occurrences), green (302) and red (222), whereas the non-basic terms include, among others, violet (46) and cyan (4). In this paper, we investigate the uses of these and other colour words, focusing mainly on their occurrence in names of chemical compounds and other terms as well as in descriptions.&#x0D;

Picosecond laser patterning for ultrathin spectrally selective solar mini-modules with transparent metal-oxide multilayer electrodes

Semitransparent solar cells featuring spectrally selective light transmission have been developed for agrivoltaic applications. One novel approach for this technology is the combination of a metal-oxide multilayer electrode with an ultrathin germanium solar cell. However, the combination of this electrode possessing multiple thin silver layers with the ultrathin absorber imposes additional challenges for the laser scribing processes that are used for the module integration. In this work, we report on a picosecond laser patterning approach for the monolithic interconnection of a spectrally selective solar cell on mini-module level. We found, that a green (532 nm) and an infrared laser (1064 nm) are suitable for the scribing of the metal-oxide multilayer electrode and the ultrathin absorber. Our approach is an important step towards large scale module fabrication for versatile agrivoltaic applications.

Cooperative Active Power Management in Multifrequency Microgrid With an Energy Storage System Based on Distance of Source to Load

A multifrequency microgrid (MFMG), which has different frequency voltages and currents on the multifrequency (MF) bus can be constructed based on superposition theorem, orthogonal power flow theory, and frequency selective power transmission criteria. It is a unique system where different frequency powers are present on the bus and all active powers maintain orthogonality by flowing simultaneously through a conductor without mixing. Due to the uncertainty and intermittency of renewable sources, an energy storage system (ESS) needs to be installed with MFMG to maintain stability and reliability. The ESS will be charged/discharged based on different frequency active power imbalances in the MF bus. Due to the presence of different frequency voltages and currents on the MF bus, the integration of ESS with MFMG is challenging but not yet discussed in any literature. In this paper, an architecture of MFMG is proposed with ESS. It is found that different new power imbalance cases arise in MFMG due to different frequency sources and loads, which are not present in traditional microgrids. Here, active power balancing conditions for all power imbalance cases are defined for grid connected and islanded mode. An algorithm is proposed to coordinate the ESS and different renewable sources to balance different frequency active power demands in MFMG for optimum power generation through communication under a cooperative framework. The framework is created based on the assumption that any load prefers to take power from the nearest source to minimize the power loss and cost. Different source load pairs are categorized based on the physical distance by different frequencies and accordingly the algorithm is structured. Finally, Matlab simulation of a sample 9 bus MFMG is performed to validate the algorithm and all results are presented.

Two-dimensional nanofluidics for blue energy harvesting

Blue energy harvesting based on the ion flow obtained from seas and rivers provides a clean, stable and continuous electric output that is highly dependent on ion-selective membranes (ISMs) that conduct single ions. In recent years, ISMs constructed based on two-dimensional (2D) nanofluidics have demonstrated promising application prospects in blue energy harvesting due to their facile fabrication, excellent ion selectivity and high ion flux. In this review, the principles of 2D nanofluidics in regulating ionic transport are firstly proposed and discussed, including ion selectivity and ultrafast ion transmission, which are considered as two critical factors for achieving highly efficient blue energy harvesting. The advantages of 2D nanofluidics towards blue energy harvesting are analyzed to reveal the necessity of this review. The construction of 2D nanofluidic membranes based on several typical materials and their recent research advances in salinity gradient- and pressure-driven blue energy harvesting are also summarized in detail. Finally, the existing challenges of 2D nanofluidic membranes regarding blue energy harvesting applications are discussed to provide new insights for the development of high-performance blue energy harvesting systems based on 2D nanofluidics.

VTrust: Remotely Executing Mobile Apps Transparently With Local Untrusted OS

Increasingly, many security and privacy sensitive applications (apps for short) are running in the mobile platforms. However, as the mobile operating systems are becoming increasingly sophisticated, they are vulnerable to various attacks. In addressing the need of running high assurance mobile apps in a secure environment even though the operating systems are untrusted, this paper presents VTRUST, a new mobile app trusted execution environment, which offloads the general execution and storage of a mobile app to a trusted remote server (e.g., a VM running in a cloud) and secures the I/O between the server and the mobile device with the aid of a trusted hypervisor on the mobile device. Specifically, VTRUST establishes an encrypted I/O channel between the local hypervisor and the remote server, such that any sensitive data flowing through the mobile OS, which is hosted by the hypervisor, is encrypted from the perspective of the local mobile OS. To enhance the performance of VTRUST, we have also designed multiple optimizations, such as output data compression and selective sensor data transmission. We have implemented VTRUST and our evaluation shows that it has limited impact on both user experience and the app performance.

Ultra-Reliable Communication for Critical Machine Type Communication via CRAN-Enabled Multi-Connectivity Diversity Schemes.

This paper focuses on edge-enabled cloud radio access network architecture to achieve ultra-reliable communication, a crucial enabler for supporting mission-critical machine-type communication networks. We propose coordinated multi-point transmission schemes taking advantage of diversity mechanisms in interference-limited downlink cellular networks. The network scenario comprises spatially distributed multiple remote radio heads (RRHs) that may cooperate through silencing, or by using more elaborated diversity strategies such as maximum ratio transmission or transmit antenna selection to serve user equipment in the ultra-reliable operation regime. We derive an exact closed-form expression for the outage probabilities and expected values of signal-to-interference ratio for silencing, transmit antenna selection and maximum ratio transmission schemes. We formulate rate control and energy efficiency under reliability constraints to test the performance and resource usage of the proposed schemes. Furthermore, we study the impact on average system sum throughput with throughput-reliability trade-off under cooperative communication. Extensive numerical analysis shows the feasibility of ultra-reliable communication by implementing diversity schemes with RRHs cooperation.

An adaptive multi-hop routing with IoT abstraction for minimizing delay-node capacity trade-offs in mobile ad-hoc network

&lt;span&gt;Delay and node capacity are incompatible mobile ad hoc constraints because of the network's versatility and self-disciplined design. &lt;/span&gt;&lt;span&gt;It is a challenging problem to maximize the trade-off between the above mobility correlation factors. &lt;/span&gt;&lt;span&gt;This manuscript proposes an adaptive multi-hop routing (A.M.R.) for mobile ad-hoc network (MANET) to minimize the trade-off by integrating the internet of things (IoT). IoT nodes' smart computing and offloading abilities are extended to ad-hoc nodes to improve routing and transmission. Dor MANET nodes in route exploration, neighbor selection, and data transmission, the beneficial features of IoT include enhanced decision making. The traditional routing protocols use IoT at the time of the neighbor discovery process in updating the routing table and localization. &lt;/span&gt;&lt;span&gt;The harmonizing technologies with their extended support improve the performance of MANETs has been estimated. The proposed method achieves better throughput (14.16 Mbps), delay (0.118), packet drop (126), and overhead (36 packets) when compared to existing methods.&lt;/span&gt;

Spin selective electron transmission through a layered structure subjected to light irradiation: Efficient engineering

This work deals with engineering spin selective electron transmission through a layered structure where a ferromagnetic (FM) system is clamped between two non-magnetic (NM) regions. The site energies of NM layers are modulated in the well-known Aubry-Andre-Harper (AAH) form, and the FM layer is subjected to a light irradiation. The interplay between the cosine modulation and light irradiation brings several interesting features in spin-dependent transport which we investigate in detail within a tight-binding (TB) prescription following the Green's function formalism. The effect of irradiation is included within a minimal coupling scheme based on the Floquet ansatz. High degree of spin polarization together with its phase reversal can be obtained at multiple energy regions. The proposed prescription can be utilized to design efficient spintronic devices, and can be generalized to other similar kinds of fascinating systems.

Impact of Clostridioides difficile Therapy on Nosocomial Acquisition of Vancomycin-Resistant Enterococci.

Vancomycin is frequently used for the treatment of C. difficile infections (CDI). There are concerns that this might increase the risk of selecting vancomycin resistant enterococci (VRE). Here, we evaluated whether there is an increased risk of VRE acquisition following vancomycin for CDI specific treatment. Patients with CDI, metronidazole, or oral vancomycin treatment and without preexisting VRE were monitored for VRE acquisition. VRE isolates from patients with acquired and preexisting colonization were collected and subjected to whole genome sequencing. In total, 281 patients (median age 56 years, 54% of the male sex) presented with toxin positive C. difficile. Of them, 170 patients met the inclusion criteria, comprising 37 patients treated with metronidazole and 133 treated with oral vancomycin. In total, 14 patients meeting the inclusion criteria acquired VRE (vancomycin: n = 11; metronidazole: n = 3). Statistical analysis revealed no significant differences between both VRE acquisition rates. Genetic comparison of detected VRE isolates resulted in eight clusters of closely related genotypes comprising acquired and preexisting strains. Our results suggest that vancomycin and metronidazole likewise increase the risk of VRE acquisition. Genetic comparison indicates that VRE acquisition is a result of both antibiotic selection and pathogen transmission.

Giant Extra-Ordinary Near Infrared Transmission from Seemingly Opaque Plasmonic Metasurface: Sensing Applications.

In the present study, we report giant extra-ordinary transmission of near infrared (NIR) light, more than 90%, through a seemingly opaque plasmonic metasurface, which consists of two metal nano-slits arrays (MNSAs) with alternate opening arrangements. By using perfect coupling of the plasmonic modes formed between the sharp edges of the upper and lower MNSAs of silver, a giant, wavelength selective transmission could be obtained. The study is accompanied by optimization of electromagnetic (EM) field coupling for different interlayer spacings and lateral overlap between the two MNSAs to understand their significance in light transmission through the metasurface. The interlayer spacing between the MNSAs works as the transmitting channel for light. The optimization of performance with different fill factors and plasmonic metals was performed as well. Because of the excitation of extended surface plasmons (ESPs) generated at both the MNSAs, the metasurface can be used for refractive index (RI) sensing as one of its applications by using a transparent and flexible polymer, such as polydimethylsiloxane (PDMS), as substrate. The maximum sensitivity which could be achieved for the optimal configuration of the metasurface was 1435.71 nm/RIU, with a figure of merit (FOM) of 80 RIU−1 for 90.45% optical transmission of light for the refractive index variation of analyte medium from 1.33 to 1.38 RIU. The present study strengthens the concept of light funneling through subwavelength structures due to plasmons, which are responsible for light transmission through this seemingly opaque metasurface and finds use in highly sensitive, flexible, and cost-effective EOT-based sensors.

SARS-CoV-2 mutational cascades and the risk of hyper-exponential growth

The emergence of novel SARS-CoV-2 variants of concern (VOC), in late 2020, with selective transmission advantage and partial immunity escape potential, has been driving further evolution in the pandemic. The timing of mutational evolution and its limits are thus of paramount importance in preparedness planning. Here, we present a model predicting the pattern of epidemic growth including the emergence of variants through mutation. It is based on the SEIR (Susceptible, Exposed, Infected, Removed) model, but its equations are modified according to the transmission parameters of novel variants. Since more transmissible strains will drive a further increase in the number of cases, they will also lead to further novel mutations. As one cannot predict whether there is a viral mutational evolutionary limit, we model a cascade that could lead to hyper-exponential growth (HEG) involving the emergence of even more transmissible mutants that could overwhelm any systematic response. Our results are consistent with the timing, since the beginning of the pandemic, of the concurrent and independent emergence of the VOCs. The current dominance of the Delta variant and the need for additional public health measures indicates some of the risks of a possible HEG. We examine conditions that favor the expected appearance of similar variants, thus enabling better preparedness and more targeted research.

Scalable bacterial cellulose biofilms with improved ion transport for high osmotic power generation

The manufacture of large-sized material with tunable nanochannel size and high ion selectivity is always a challenge for osmotic power generation. Herein, we develop negatively charged carboxymethyl bacterial cellulose membranes (BC-CMC) and positively charged chitosan quaternary ammonium bacterial cellulose membranes (BC-HACC) with adjustable charge density and nanochannel size by in situ culture. The scalable membranes are suitable for rapidly ion selective transmission process. When applying the charged BC membranes for an osmotic energy harvesting device, an output power density of 2.25 W m −2 can be reached. Further connecting 15 units of the charged BC device, the output voltage can reach up to 2.53 V, which can directly power the electronic devices. This work highlights the advantage of large-scale preparation by the biosynthesis method, which can simultaneously tune the surface properties and nanochannel size of BC to regulate the ion transport behavior. We offer an easy and scalable method to obtain low-cost membranes for high osmotic energy conversion device, providing the feasibility for their large-scale application. • This paper offers a simple in situ biosynthetic modification to obtain charged BC membranes. • The scalable membranes are suitable for ion selective transmission process. • The BC-RED device can achieve an output power density of 2.25 W m −2 . • Our work develops low-cost, large-scale charged BC membranes potential in practical osmotic energy collection.

Magnetic textures and singularities in ferri/ferromagnetic multilayers

The stacking of ferrimagnetic and ferromagnetic films leads to a competition between magnetic interactions that can stabilize Bloch points and other singularities at the interfaces. In this work, GdxCo1-x/NdCo5/GdyCo1-y trilayers, with different thicknesses, have been prepared. By tuning the stoichiometry of the Gd-Co outer layers, the Co magnetic sublattice dominates in one layer, whereas the opposite side is Gd dominated. In this way, in-depth magnetization domain walls can be created due to the balance between exchange and magnetostatic interactions. In addition, the weak perpendicular magnetic anisotropy of the Nd-Co central layer induces a stripe domain pattern, supporting the formation of Bloch points, meron-like textures, and vortex-antivortex pairs. The interaction between both types of structures, in-depth domain walls and magnetic singularities, has been studied by a combination of macroscopic Magneto-Optical Kerr Effect and Vibrating Sample Magnetometry measurements with microscopic Magnetic Force Microscopy and element selective magnetic Transmission soft X-ray Microscopy imaging. The results confirm marked changes in the magnetic properties of the trilayers, as compared with those single NdCo5 films, and the formation of complex magnetic textures, associated with partial magnetization reversal, where magnetic singularities are formed.

Integrated Multiplex Sensing Bandage for In Situ Monitoring of Early Infected Wounds.

Infection, the most common complication of chronic wounds, has placed tremendous burden on patients and society. Existing care strategies could hardly reflect in situ wound status, resulting in overly aggressive or conservative therapeutic options. Multiplexed tracking of wound markers to obtain diagnostic information in a more accurate way is highly promising and in great demand for the emerging development of personalized medicine. Here, an integrated multiplex sensing bandage (MSB) system, including a multiplex sensor array (MSA), a corresponding flexible circuit, and a mobile application, was developed for real-time monitoring of sodium, potassium, calcium, pH, uric acid, and temperature indicators in the wound site to provide a quantitative diagnostic basis. The MSB was optimized for wound-oriented management applications, which exhibits a broad linear response, excellent selectivity, temporal stability, mechanical stability, reproducibility, and reliable signal transmission performance on the aforementioned physiological indicators. The results of in vivo experiments demonstrate that the MSA is capable of real-time monitoring of actual wounds as well as early prediction of infection. The results ultimately point to the potential clinical applicability of the MSB, which might benefit the quantifications of the complexity and diversity of the wound healing process. This work provides a unique strategy that holds promise for broad application in optimizing wound management and even coping with other diseases.

Dual‐polarized frequency selective rasorber with dual absorption bands

AbstractA dual‐polarized three‐dimensional absorptive frequency selective transmission (AFST) structure consisting of bent metallic strips embedded with chip‐resistors, and a parallel plate waveguide has been introduced. The structure exhibits two wide absorption bands which flank both sides of the passband, and each absorption band contains two reflection zeros contributing to the wideband performance. An equivalent circuit model is derived to investigate the design concept. A prototype is fabricated and measured, and good agreement between the simulated and experimental results is obtained. In addition, the AFST shows a stable response even for oblique angles and for both TE‐ and TM‐polarizations.