Drone Controller Localization Based on RSSI Ratio.

We proposed two methods for the localization of drone controllers based on received signal strength indicator (RSSI) ratios: the RSSI ratio fingerprint method and the model-based RSSI ratio algorithm. To evaluate the performance of our proposed algorithms, we conducted both simulations and field trials. The simulation results show that our two proposed RSSI-ratio-based localization methods outperformed the distance mapping algorithm proposed in literature when tested in a WLAN channel. Moreover, increasing the number of sensors improved the localization performance. Averaging a number of RSSI ratio samples also improved the performance in propagation channels that did not exhibit location-dependent fading effects. However, in channels with location-dependent fading effects, averaging a number of RSSI ratio samples did not significantly improve the localization performance. Additionally, reducing the grid size improved the performance in channels with small shadowing factor values, but this only resulted in marginal gains in channels with larger shadowing factors. Our field trial results align with the simulation results in a two-ray ground reflection (TRGR) channel. Our methods provide a robust and effective solution for the localization of drone controllers using RSSI ratios.

On the explanation of hysteresis in the adsorption of ammonia on graphitized thermal carbon black.

We present a Monte Carlo simulation and experimental study of ammonia adsorption on graphitized thermal carbon black. Our new molecular model for the adsorbent is composed of basal plane graphene surfaces with ultrafine pores grafted with hydroxyl groups at the junctions between graphene layers. The simulated adsorption isotherms and isosteric heats are in good agreement with the experimental data of Holmes and Beebe, and the simulations reproduce the unusual experimental hysteresis of ammonia adsorption on an open graphite surface for the first time in the literature. The detailed mechanisms of adsorption and desorption, and the origin of hysteresis, are investigated by the microscopic analysis of the adsorbate structures to show that restructuring occurs during adsorption. The main results from this work are: (i) at the triple point, ammonia adsorbs preferentially around the functional groups to form clusters in the ultrafine pores and spills-over onto the basal plane as the loading is increased; followed by a 2D condensation on the graphite surface to form a bilayer adsorbate; (ii) at the boiling point, adsorption occurs on the basal plane due to the increasing importance of thermal fluctuations (an entropic effect); (iii) the isosteric heat is very high at zero loading due to the strong interaction between ammonia and the functional groups, decreases steeply when the functional group is saturated, and eventually reaches the heat of condensation as the fluid-fluid interaction increases.

Existence of ultrafine crevices and functional groups along the edge surfaces of graphitized thermal carbon black.

Adsorption of different gases on graphitized thermal carbon black (GTCB) has been studied with a new molecular model to examine the consequences of micropore crevices and functional groups at the junctions between adjacent basal planes. Adsorption was simulated in the Grand Canonical Monte Carlo ensemble and the theoretical Henry constants were calculated by Monte Carlo volume integration over the Boltzmann factor of the solid-fluid potential. The simulation results are in good agreement with high-resolution experimental isotherms for argon on mineralogical graphite measured by Lopez-Gonzalez et al.1 From detailed inspection of the argon isotherms at extremely low coverages, we find two distinct Henry law regions, separated by a plateau (suggesting saturation of the stronger sites) that spans over a few decades of pressure. The first Henry law region is attributed to adsorption in the ultrafine crevices at the junctions between two adjacent basal planes, and the second region corresponds to adsorption on the basal plane, as confirmed by the theoretical Henry constant. The simulated isosteric heat and snapshots of molecular configurations show that argon adsorbs preferentially in the ultrafine crevices where there is a deep potential well due to overlap from the opposite pore walls. Similar behavior was found for other nonassociating fluids (Ar, N2, and CO2); however, for associating fluids (NH3 and H2O), the strong sites for adsorption and nucleation come from the combined effects of functional groups and ultrafine crevices, since the latter cannot alone account for the observed adsorption.

An undulation theory for condensation in open end slit pores: critical hysteresis temperature & critical hysteresis pore size.

A new theory of condensation in an open end slit pore, based on the concept of temperature dependent undulation, at the interface separating the adsorbed phase and the gas-like region, is presented. The theory, describes, for the first time, the microscopic origin of the critical hysteresis temperature and the critical hysteresis pore size, properties which are not accessible to any classical theories.

Unveiling Chinese senior high school EFL students' burnout and engagement: Profiles and antecedents.

Burnout impairs English as a foreign language (EFL) learning, while engagement enhances it. However, most relevant studies have focused on college students, neglecting senior high school students. To address this gap, this mixed-methods study used two scales to assess the levels of burnout and engagement among 1234 Chinese senior high school EFL students. We also applied a person-centered approach with a statistical software (Mplus 8.7) to identify their latent profiles. Then, we conducted semi-structured interviews with 30 students and analyzed the data using thematic analysis with a qualitative software (MAXQDA 2022) to investigate the antecedents of their burnout and engagement. The statistical analysis revealed three profiles: high burnout-low engagement (16.0 %), moderate burnout-moderate engagement (61.8 %), and low burnout-high engagement (22.2 %). The profiles were associated with demographic characteristics such as gender, age, and grade. The thematic analysis identified four major antecedents: high academic stress and low academic support for burnout, and high external support and high internal support for engagement. Each major antecedent consisted of several categories and subcategories. This study could inform the design of effective interventions to reduce Chinese EFL students' burnout and increase their engagement.

Validating the AI-assisted second language (L2) learning attitude scale for Chinese college students and its correlation with L2 proficiency.

The positive impact of Artificial Intelligence (AI) on second language (L2) learning is well-documented. An individual's attitude toward AI significantly influences its adoption. Despite this, no specific scale has been designed to measure this attitude, particularly in the Chinese context. To address this gap, our study aims to construct the AI-Assisted L2 Learning Attitude Scale for Chinese College Students (AL2AS-CCS) and evaluate its reliability, validity, and relationship with L2 proficiency. Our research comprises two phases, each involving separate samples. In Phase One (Sample 1: n = 379), we conducted exploratory factor analysis (EFA) to determine the factor structure of the AL2AS-CCS. The resulting two-factor structure consists of 12 items, categorized into cognitive and behavioral components. In Phase Two (Sample 2: n = 429), we performed confirmatory factor analysis (CFA) to validate the factor structure and assess model fit. CFA in Sample 2 confirmed the factor structure and demonstrated a good model fit. Additionally, the AL2AS-CCS exhibited high criterion validity, internal consistency, and cross-gender invariance. Our findings suggest that the AL2AS-CCS is a valid measurement tool for assessing Chinese college students' attitude toward AI-assisted L2 learning. Moreover, Chinese college students were discovered to maintain a moderately positive attitude toward AI-assisted L2 learning. Additionally, a positive correlation was identified between this attitude and their L2 proficiency.

Exploring the Impact of a Supportive Work Environment on Chinese L2 Teachers' Emotions: A Partial Least Squares-SEM Approach.

Second language (L2) teachers' emotions can influence their well-being and students' performance. However, most of the existing studies have focused on the role of individual factors in affecting L2 teachers' emotions, while leaving environmental factors underexplored. To fill this gap, this study aimed to examine how the four dimensions of a supportive work environment (SWE) (perceived climate, PC; supervisory relationship, SR; peer group interaction, PGI; and perceived organization support, POS) relate to L2 teachers' emotions (enjoyment, anxiety, pride, and anger). A sample of 406 Chinese L2 teachers completed two valid scales to measure their SWE and emotions. The data were analyzed by Partial Least Squares-Structural Equation Modeling (SEM) using Smart PLS 3 software. The results showed that (1) PC, PGI, and POS had a positive and significant effect on enjoyment, while SR had no significant effect; (2) PGI and POS had a negative and significant effect on anxiety, while PC and SR had no significant effect; (3) PGI had a positive and significant effect on pride, while the other three dimensions had no significant effect; and (4) POS had a negative and significant effect on anger, while the other three dimensions had no significant effect. The study concludes with some implications for L2 teachers' education.

In-Situ Construction of Anti-Aggregation Tellurium Nanorods/Reduced Graphene Oxide Composite to Enable Fast Sodium Storage.

Sodium-ion batteries (SIBs) as a replaceable energy storage technology have attracted extensive attention in recent years. The design and preparation of advanced anode materials with high capacity and excellent cycling performance for SIBs still face enormous challenges. Herein, a solution method is developed for in situ synthesis of anti-aggregation tellurium nanorods/reduced graphene oxide (Te NR/rGO) composite. The material working as the sodium-ion battery (SIB) anode achieves a high reversible capacity of 338 mAh g-1 at 5 A g-1 and exhibits up to 93.4% capacity retention after 500 cycles. This work demonstrates an effective preparation method of nano-Te-based composites for SIBs.

Enhanced Photodetection Range from Visible to Shortwave Infrared Light by ReSe2/MoTe2 van der Waals Heterostructure.

Type II vertical heterojunction is a good solution for long-wavelength light detection. Here, we report a rhenium selenide/molybdenum telluride (n-ReSe2/p-MoTe2) photodetector for high-performance photodetection in the broadband spectral range of 405-2000 nm. Due to the low Schottky barrier contact of the ReSe2/MoTe2 heterojunction, the rectification ratio (RR) of ~102 at ±5 V is realized. Besides, the photodetector can obtain maximum responsivity (R = 1.05 A/W) and specific detectivity (D* = 6.66 × 1011 Jones) under the illumination of 655 nm incident light. When the incident wavelength is 1550-2000 nm, a photocurrent is generated due to the interlayer transition of carriers. This compact system can provide an opportunity to realize broadband infrared photodetection.

Mid-Infrared Optoelectronic Devices Based on Two-Dimensional Materials beyond Graphene: Status and Trends.

Since atomically thin two-dimensional (2D) graphene was successfully synthesized in 2004, it has garnered considerable interest due to its advanced properties. However, the weak optical absorption and zero bandgap strictly limit its further development in optoelectronic applications. In this regard, other 2D materials, including black phosphorus (BP), transition metal dichalcogenides (TMDCs), 2D Te nanoflakes, and so forth, possess advantage properties, such as tunable bandgap, high carrier mobility, ultra-broadband optical absorption, and response, enable 2D materials to hold great potential for next-generation optoelectronic devices, in particular, mid-infrared (MIR) band, which has attracted much attention due to its intensive applications, such as target acquisition, remote sensing, optical communication, and night vision. Motivated by this, this article will focus on the recent progress of semiconducting 2D materials in MIR optoelectronic devices that present a suitable category of 2D materials for light emission devices, modulators, and photodetectors in the MIR band. The challenges encountered and prospects are summarized at the end. We believe that milestone investigations of 2D materials beyond graphene-based MIR optoelectronic devices will emerge soon, and their positive contribution to the nano device commercialization is highly expected.

Synthesis and stabilization of black phosphorus and phosphorene: recent progress and perspectives.

Two-dimensional black phosphorus (BP) has triggered tremendous research interest owing to its unique crystal structure, high carrier mobility, and tunable direct bandgap. Preparation of few-layer BP with high quality and stability is very important for its related research and applications in biomedicine, electronics, and optoelectronics. In this review, the synthesis methods of BP, including the preparation of bulk BP crystal which is an important raw material for preparing few-layer BP, the popular top-down methods, and some direct growth strategies of few-layer BP are comprehensively overviewed. Then chemical ways to enhance the stability of few-layer BP are concretely introduced. Finally, we propose a selection rule of preparation methods of few-layer BP according to the requirement of specific BP properties for different applications. We hope this review would bring some insight for future researches on BP and contributes to the acceleration of BP's commercial progress.

Repression of Interlayer Recombination by Graphene Generates a Sensitive Nanostructured 2D vdW Heterostructure Based Photodetector.

Great success in 2D van der Waals (vdW) heterostructures based photodetectors is obtained owing to the unique electronic and optoelectronic properties of 2D materials. Performance of photodetectors based 2D vdW heterojunctions at atomic scale is more sensitive to the nanointerface of the heterojunction than conventional bulk heterojunction. Here, a nanoengineered heterostructure for the first-time demonstration of a nanointerface using an inserted graphene layer between black phosphorus (BP) and InSe which inhibits interlayer recombination and greatly improves photodetection performances is presented. In addition, a transition of the transport characteristics of the device is induced by graphene, from diffusion motion of minority carriers to drift motion of majority carriers. These two reasons together with an internal photoemission effect make the BP/G/InSe-based photodetector have ultrahigh specific detectivity at room temperature. The results demonstrate that high-performance vdW heterostructure photodetectors can be achieved through simple structural manipulation of the heterojunction interface on nanoscale.

Electronic and Optical Properties of Two-Dimensional Tellurene: From First-Principles Calculations.

Tellurene is a new-emerging two-dimensional anisotropic semiconductor, with fascinating electric and optical properties that differ dramatically from the bulk counterpart. In this work, the layer dependent electronic and optical properties of few-layer Tellurene has been calculated with the density functional theory (DFT). It shows that the band gap of the Tellurene changes from direct to indirect when layer number changes from monolayer (1 L) to few-layers (2 L-6 L) due to structural reconstruction. Tellurene also has an energy gap that can be tuned from 1.0 eV (1 L) to 0.3 eV (6 L). Furthermore, due to the interplay of spin-orbit coupling (SOC) and disappearance of inversion symmetry in odd-numbered layer structures resulting in the anisotropic SOC splitting, the decrease of the band gap with an increasing layer number is not monotonic but rather shows an odd-even quantum confinement effect. The optical results in Tellurene are layer dependent and different in E ⊥ C and E || C directions. The correlations between the structure, the electronic and optical properties of the Tellurene have been identified. Despite the weak nature of interlayer forces in their structure, their electronic and optical properties are highly dependent on the number of layers and highly anisotropic. These results are essential in the realization of its full potential and recommended for experimental exploration.

PPAR-α improves the recovery of lung function following acute respiratory distress syndrome by suppressing the level of TGF-ß1.

Although peroxisome proliferator-activated receptor (PPAR)-α has been reported to be involved in preventing acute lung injury (ALI), the molecular regulation of post­ALI lung recovery remains to be fully elucidated. The aim of the present study was to characterize the mechanism by which PPAR­α prevents ALI and examine the role of PPAR­α in the recovery of lung function following acute respiratory distress syndrome (ARDS). Reverse transcription­quantitative­polymerase chain reaction and western blot analyses suggested that PPAR­α was effective in suppressing transforming growth factor (TGF)­ß1 in HLF cells and RAW 264.7 cells. In an ALI mouse model, PPAR­α treatment prior to stimulation with lipopolysaccharide (LPS) resulted in a decrease in the expression of TGF­ß1 in bronchoalveolar lavage fluid (BALF), peripheral blood and splenocytes. The injection of a virus expressing short hairpin PPAR­α into mice following LPS treatment resulted in a dose­dependent increase in lung resistance index and decrease in dynamic compliance, and a significant increase in BALF protein, which indicated PPAR­α was essential for the recovery of lung function following ALI. Of note, the serum expression of PPAR­α was inversely correlated with TGF­ß1 and negatively correlated with disease severity in patients with ARDS. These data suggested that PPAR­α was essential for the recovery of lung function following ALI by the suppression of TGF­ß1, which reveals a previously unappreciated mechanism controlling post­ALI lung recovery.

On the isosteric heat of adsorption of non-polar and polar fluids on highly graphitized carbon black.

Isosteric heat of adsorption is indispensable in probing the energetic behavior of interaction between adsorbate and solid, and it can shed insight into how molecules interact with a solid by studying the dependence of isosteric heat on loading. In this study, we illustrated how this can be used to explain the difference between adsorption of non-polar (and weakly polar) fluids and strong polar fluids on a highly graphitized carbon black, Carbopack F. This carbon black has a very small quantity of functional group, and interestingly we showed that no matter how small it is the analysis of the isosteric heat versus loading can identify its presence and how it affects the way polar molecules adsorb. We used argon and nitrogen as representatives of non-polar fluid and weakly polar fluid, and methanol and water for strong polar fluid. The pattern of the isosteric heat versus loading can be regarded as a fingerprint to determine the mechanism of adsorption for strong polar fluids, which is very distinct from that for non-polar fluids. This also allows us to estimate the interplay between the various interactions: fluid-fluid, fluid-basal plane and fluid-functional group.

The interplay between molecular layering and clustering in adsorption of gases on graphitized thermal carbon black--spill-over phenomenon and the important role of strong sites.

We analyse in detail our experimental data, our simulation results and data from the literature, for the adsorption of argon, nitrogen, carbon dioxide, methanol, ammonia and water on graphitized carbon black (GTCB), and show that there are two mechanisms of adsorption at play, and that their interplay governs how different gases adsorb on the surface by either: (1) molecular layering on the basal plane or (2) clustering around very strong sites on the adsorbent whose affinity is much greater than that of the basal plane or the functional groups. Depending on the concentration of the very strong sites or the functional groups, the temperature and the relative strength of the three interactions, (a) fluid-strong sites (fine crevices and functional group) (F-SS), (b) fluid-basal plane (FB) and (c) fluid-fluid (FF), the uptake of adsorbate tends to be dominated by one mechanism. However, there are conditions (temperature and adsorbate) where two mechanisms can both govern the uptake. For simple gases, like argon, nitrogen and carbon dioxide, adsorption proceeds by molecular layering on the basal plane of graphene, but for water which represents an extreme case of a polar molecule, clustering around the strong sites or the functional groups at the edges of the graphene layers is the major mechanism of adsorption and there is little or no adsorption on the basal planes because the F-SS and FF interactions are far stronger than the FB interaction. For adsorptives with lower polarity, exemplified by methanol or ammonia, the adsorption mechanism switches from clustering to layering in the order: ammonia, methanol; and we suggest that the bridging between these two mechanisms is a molecular spill-over phenomenon, which has not been previously proposed in the literature in the context of physical adsorption.

Facile functionalization of polypeptides by thiol-yne photochemistry for biomimetic materials synthesis.

Rapid and highly efficient side-chain functionalization of polypeptides was achieved via combination of ring-opening polymerization of a new clickable monomer of γ-propargyl-L-glutamate N-carboxyanhydride (PLG-NCA) and thiol-yne photochemistry, which provides a convenient and universal route to prepare diverse polypeptide-based biomimetic hybrid materials.