Interaction Mechanism Research Articles

Flotation separation of chalcopyrite from pyrite and sphalerite using a novel collector: An experimental and mechanism investigation

In this paper, a new collector, named O-isobutyl-N-allyl thionocarbamate (IBATC), was synthesized, and the structure was characterized by Fourier Transform Infrared Spectrometer (FTIR) and 1H NMR, 13C NMR analysis. The collection performance of IBATC was evaluated by flotation tests and interaction mechanism was investigated by means of adsorption amount, zeta potential measurements, FTIR, X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculation. The flotation tests results proved that IBATC was inclined to collect chalcopyrite compared with pyrite and sphalerite. Especially in the pH range of 9.5–10 and IBATC concentrate of 30–40 mg/L, the recovery of chalcopyrite exhibited more than 80 %. The adsorption amount and zeta potential measurements showed that IBATC had a greater orientation to chalcopyrite. FTIR and XPS analysis demonstrated IBATC chemically adsorbed on chalcopyrite surface, whereas physically adsorbed on pyrite and sphalerite. Further, DFT calculation of the interaction between IBATC and chalcopyrite proved that S atom of IBATC donated electrons to Cu sites on chalcopyrite surface and the adsorption energy was −19.45 kcal/mol, referring to an exothermic reaction. As a result, IBATC showed great capacity for the separation flotation of chalcopyrite, pyrite and sphalerite.

An investigation of the binding of two cinnamate UV filters to bovine serum albumin separately and simultaneously

A study of the separate/simultaneous interaction mechanism between two common cinnamate ultraviolet filters (UVFs), Octtocrylene (OC) and 2-ethylhexyl 4-methoxycinnamate (EHMC), with bovine serum albumin (BSA) was conducted. Both OC and EM can bind to BSA. A more obvious fluorescence quenching effect was observed with EHMC on BSA, as well as a stronger affinity for BSA and a greater effect on the amino acid microenvironment. UVFs and BSA's binding constants were decreased when EHMC and OC interacted simultaneously with BSA, while the distance between UVFs and BSA was increased. Coexistence affected both OC and EHMC, making them less able to binding to BSA. While binding simultaneously to EHMC and OC, BSA's secondary structure underwent significant changes.

Molecular insights into oil detachment from hydrophobic quartz surfaces in clay-hosted nanopores during steam–surfactant co-injection

Thermal recovery techniques for producing oil sands have substantial environmental impacts. Surfactants can efficiently improve thermal bitumen recovery and reduce the required amount of steam. Such a technique requires solid knowledge about the interaction mechanism between surfactants, bitumen, water, and rock at the nanoscale level. In particular, oil sands ores have extremely complex mineralogy as they contain many clay minerals (montmorillonite, illite, kaolinite). In this study, molecular dynamics simulation is carried out to elucidate the unclear mechanisms of clay minerals contributing to the bitumen recovery under a steam–anionic surfactant co-injection process. We found that the clay content significantly influenced an oil detachment process from hydrophobic quartz surfaces. Results reveal that the presence of montmorillonite, illite, and the siloxane surface of kaolinite in nanopores can enhance the oil detachment process from the hydrophobic surfaces because surfactant molecules have a stronger tendency to interact with bitumen and quartz. Conversely, the gibbsite surfaces of kaolinite curb the oil detachment process. Through interaction energy analysis, the siloxane surfaces of kaolinite result in the most straightforward oil detachment process. In addition, we found that the clay type presented in nanopores affected the wettability of the quartz surfaces. The quartz surfaces associated with the gibbsite surfaces of kaolinite show the strongest hydrophilicity. By comparing previous experimental findings with the results of molecular dynamics (MD) simulations, we observed consistent wetting characteristics. This alignment serves to validate the reliability of the simulation outcomes. The outcome of this paper makes up for the lack of knowledge of a surfactant-assisted bitumen recovery process and provides insights for further in-situ bitumen production engineering designs.

Identification of shared molecular mechanisms and diagnostic biomarkers between heart failure and idiopathic pulmonary fibrosis

BackgroundHeart failure (HF) and idiopathic pulmonary fibrosis (IPF) are global public health concerns. The relationship between HF and IPF is widely acknowledged. However, the interaction mechanisms between these two diseases remain unclear, and early diagnosis is particularly difficult. Through the integration of bioinformatics and machine learning, our work aims to investigate common gene features, putative molecular causes, and prospective diagnostic indicators of IPF and HF. MethodsThe Gene Expression Omnibus (GEO) database provided the RNA-seq datasets for HF and IPF. Utilizing a weighted gene co-expression network analysis (WGCNA), possible genes linked to HF and IPF were found. The Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) were then employed to analyze the genes that were shared by HF and IPF. Using the cytoHubba and iRegulon algorithms, a competitive endogenous RNA (ceRNA) network was built based on seven basic diagnostic indicators. Additionally, hub genes were identified using machine learning approaches. External datasets were used to validate the findings. Lastly, the association between the number of immune cells in tissues and the discovered genes was estimated using the CIBERSORT method. ResultsIn total, 63 shared genes were identified between HF- and IPF-related modules using WGCNA. Extracellular matrix (ECM)/structure organization, ECM-receptor interactions, focal, and protein digestion and absorption, were shown to be the most enrichment categories in GO and KEGG enrichment analysis of common genes. Furthermore, a total of seven fundamental genes, including COL1A1, COL3A1, THBS2, CCND1, ASPN, FAP, and S100A12, were recognized as pivotal genes implicated in the shared pathophysiological pathways of HF and IPF, and TCF12 may be the most important regulatory transcription factor. Two characteristic molecules, CCND1 and NAP1L3, were selected as potential diagnostic markers for HF and IPF, respectively, using a support vector machine-recursive feature elimination (SVM-RFE) model. Furthermore, the development of diseases and diagnostic markers may be associated with immune cells at varying degrees. ConclusionsThis study demonstrated that ECM/structure organisation, ECM-receptor interaction, focal adhesion, and protein digestion and absorption, are common pathogeneses of IPF and HF. Additionally, CCND1 and NAP1L3 were identified as potential diagnostic biomarkers for both HF and IPF. The results of our study contribute to the comprehension of the co-pathogenesis of HF and IPF at the genetic level and offer potential biological indicators for the early detection of both conditions.

Synergistic effect of gellan gum and guar gum on improving the foaming properties of soy protein isolate-based complexes: Interaction mechanism and interfacial behavior

Interactions among multi-component play a critical role in modulating the foaming properties of aerated foods. This study evaluated the mechanisms of synergistic improvement of gellan gum (GEG) and guar gum (GUG) on the foaming properties of soy protein isolate (SPI)-based complex. The results showed that the GEG/GUG ratio was closely related to the intermolecular interactions of SPI-based ternary complex and the dynamical changing of its foaming properties. The SPI/GEG/GUG ternary complex with a GEG/GUG ratio of 2/3 exhibited the highest foamability (195 %) and comparable foam stability (99.17 %), which were 32.95 % and 2.99 % higher than that of SPI/GEG binary complex. At this ratio, GUG promoted the interactions between SPI and GEG, and bound to complex's surface through hydrogen bonding, resulting in the increase of particle size and surface charge, and the decrease of surface hydrophobicity. Although this reduced the diffusion of complex onto the air/water interface, it increased permeation rate and molecular rearrangement behavior, which were the potential mechanisms to improve the foaming properties. Additionally, the synergistic effect of GEG and GUG also enhanced the elastic strength and solid characteristics of foam systems. This study provided a theoretical guidance for the targeted modulation of foaming properties of multi-component aerated foods.

Studies on the effects of preheated β-lactoglobulin on the physicochemical properties of theaflavin-3,3′-digallate and the interaction mechanism

Teaflavin-3,3'-digallate (TFDG) is a sensory and health benefit substance in tea beverage, but is usually eliminated during processing due to the formation of tea cream by binding with proteins. In order to retain the TFDG, β-lactoglobulin (β-LG) was used to bind with TFDG and avoid the formation of tea cream. The results of physicochemical tests and entropy weight-TOPSIS showed that the best β-LG-TFDG dispersion (TFDG concentration: 0.468 g/L) had low particle size (37.29 nm), high electrical potential (-32.43 mv), high transmittance (88.52%), and strong antioxidant activity (84.82%), when the preheated temperature of β-LG was 85 °C and the molar ratio was 1:2. The multispectral experiment results showed that TFDG interacted with β-LG via static quenching, and preheated treatment of β-LG enhanced the interaction between β-LG and TFDG. CD spectroscopy suggested that TFDG induced slight changes in the secondary structure of β-LG. The results of molecular dynamics showed that preheated treatment leading in the changes in tertiary structure of β-LG, opening of key ring region of β-LG and exposing the active cavities of β-LG, which enhances the intermolecular forces between TFDG and β-LG. What's more, molecular docking was proved that preheated treatment of β-LG enhances the hydrophobic interactions and hydrogen bonds, which dominated the interaction between TFDG and β-LG. The results proposed in this research could further reducing tea cream formation and improving the healthy and sensory performances of tea beverage by using preheated β-LG without preserving both the tea pigments and the active nutrients.

Deciphering the interaction mechanism between soy protein isolate and fat-soluble anthocyanin on experiments and molecular simulations

In this work, the acylated anthocyanin (Ca-An) was prepared by enzymatic modification of black rice anthocyanin with caffeic acid, and the binding mechanism of Ca-An to soybean protein isolate (SPI) was investigated by experiments and computer simulation to expand the potential application of anthocyanin in food industry. Multi-spectroscopic studies revealed that the stable binding of Ca-An to SPI induced the folding of protein polypeptide chain, which transformed the secondary structure of SPI trended to be flexible. The microenvironment of protein was transformed from hydrophobic to hydrophilic, while tyrosine played dominant role in quenching process. The binding sites and forces of the complexes were determined by computer simulation for further explored. The protein conformation of the 7S and 11S binding regions to Ca-An changed, and the amino acid microenvironment shifted to hydrophilic after binding. The results showed that more non-polar amino acids existed in the binding sites, while in binding process van der Waals forces and hydrogen bonding played a major role hydrophobicity played a minor role. Based on MM-PBSA analysis, the binding constants of 7S-Ca-An and 11S-Ca-An were 0.518 × 106 mol−1 and 5.437 × 10−3 mol−1, respectively. This information provides theoretical guidance for further studying the interaction between modified anthocyanins and biomacromolecules.

The interaction mechanism of tepotinib and α-glucosidase: A prelude to control type 2 diabetes mellitus

α-Glucosidase is associated with the enhancement in postprandial blood glucose. Therefore, inhibition of α-glucosidase activity could be considered as a potential strategy to control type 2 diabetes mellitus (DM). Tepotinib (TPT) as an enzyme inhibitor with a molecular formula of C29H28N6O2 has a distinct structure that may make it useful for interacting with α-glucosidase, causing conformational changes and inhibiting enzyme activity. In this study, the interaction mechanism of TPT and α-glucosidase was explored. The enzyme activity assay showed that TPT could inhibit α-glucosidase activity with the IC50 value of 0.071 ± 0.007 mg/mL (164 ± 16.5 µM), which was comparable with that of acarbose (IC50 = 0.045 ± 0.006 mg/mL = 255 ± 38.25 µM) as a clinical drug. It was further determined that Ser 241 and His 280 amino acid residues in the active site assist in the formation of the TPT-α-glucosidase complex mediated by hydrogen bonding and van der Waals forces, which might lead to the conformational folding of α-glucosidase to some extent. Additionally, the interaction of TPT and α-glucosidase reduced the surface hydrophobicity of the enzyme and altered the microenvironment around Tyr 158 amino acid residue in the active site. These findings suggested that TPT might be employed as a potential inhibitor of α-glucosidase activity, suggesting that it should be further explored in future studies to develop a TPT-based system for application in the amelioration of DM.

Synthesis, characterization, crystal structure, biological activities, and molecular docking study of the (NHC)Pd(II)(Morp) (NHC: N-heterocyclic carbene, Morp: Morpholine) complexes

In this paper, a new palladium-based (NHC)Pd(II)(Morp) complexes (NHC: N-heterocyclic carbene, Morp: morpholine) were prepared. The NHC ligand in these complexes bears the 2-chloro-4-fluorobenzyl group. All complexes were fully characterized by 1H, 13C NMR, FTIR spectroscopic and elemental analysis methods. The crystal structure of complex 1f has been determined using X-ray diffraction. Furthermore, all complexes were investigated for their ability to inhibit enzymes. All complexes exhibited highly potent inhibition effects on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) (KI values are in the range of 97.84 ± 8.97 to 132.28 ± 11.63 µM and 18.24 ± 2.08 to 39.08 ± 5.28 µM for AChE and BChE, respectively). Designing of reported compounds is impacted by molecular docking study, because with molecular docking study, it will lead to future researches by illuminating the interaction mechanism of 1a, 1b, 1c and 1f compounds with potential activity against target AChE and BChE enzymes at molecuar level

Photoluminescence and supercapacitor applications of dysprosium doped rhombohedral silver gallium oxide nanoparticles

indent Dy3+ doped Silver Gallium Oxide (AgGaO2) nanoparticles (NPs) (AGO:Dy3+) are effectively synthesized via a green mediated route using Aloe vera gel extract as a reducing agent, followed by calcination at 600 °C for 3 h. Powder X-ray diffraction (PXRD), Fourier transformation infrared (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), photoluminescence (PL), and electrochemical studies were employed to confirm the synthesis, structural, luminescence, and supercapacitor properties of the NPs. The diffraction peaks of the synthesized samples possess a trigonal structure within a rhombohedral system. The surface morphology consists of a few irregular, a few hexagonal, and a few rice grain-structured NPs. The changes in the agglomeration were observed with variations in the dopant concentration. The direct energy band gap increases from 3.11 to 3.13 eV with an increase in the dopant concentration. Under 276 nm excitation, the PL spectra of AGO:Dy3+ nanophosphors reveal robust emission peaks attributed to 4F9/2→6F15/2 (480 nm) and 4F9/2→6F13/2 (565 nm). The confirmed critical distance signifies that energy transfer occurs through a multipolar interaction mechanism. The CIE chromaticity diagram illustrates the emission of yellowish green light from the phosphors. These investigations indicate the potential applications of AGO:Dy3+ nanocrystals in a light-emitting diode as a nanophosphor material. Nanocrystals in light-emitting diodes as a nanophosphor material. Thorough electrochemical investigations, encompassing cyclic voltammetry, were conducted to decipher redox reactions, electrode kinetics, and electrochemical behavior. The precise elucidation of ion transport kinetics was achieved through Electrochemical Impedance Spectroscopy (EIS), while the determination of supercapacitance values was accomplished via Galvanostatic Charge-Discharge (GCD) analysis. The supercapacitance values exhibited a remarkable range from 76.177 to 111.53 F/g, underscoring their sensitivity to dopant concentration. Consequently, the material synthesized in this groundbreaking study exhibits substantial promise for diverse applications, spanning from energy storage materials to the dynamic landscape of display technology. Electrochemical studies

Natural rubber latex as a potential additive for water-based drilling fluids

The environmental hazards and "carbon footprint" of oil and gas drilling can be significantly reduced by replacing traditional petroleum-based chemical additives with natural materials derived from plants and animals. This paper explored for the first time the interaction mechanism between natural rubber latex (NRL) and bentonite suspensions (BTs) through a series of characterization experiments, as well as the potential applications in water-based drilling fluids (WBDF). The gel viscoelasticity experiments showed that NRL could decrease the consistency coefficient (k) and flow index (n) of BTs, and enhance the shear thinning performance of BTs as pseudo-plastic fluids. In addition, 0.5 w/v% NRL not only increased the critical yield stress and strengthened the structural strength between the bentonite particles, but also facilitated the compatibility of pressure loss and flow efficiency. The evaluation of colloidal stability and WBDF performance indicated that NRL particles could promote the hydration and charge stability on the surface of BTs particles, and optimize the particle size distribution and flow resistance of WBDF under the "intercalation-exfoliation-encapsulation" synergistic interaction. Moreover, NRL can improve the rheological properties of WBDF at high temperatures (<150 °C), and form a dense blocking layer by bridging and sealing the pores and cracks of the filter cake, which ultimately reduces the permeability of the cake and the filtration loss of WBDF.

Combined experimental and kinetic modeling study on the low-temperature oxidation of OME3/n-heptane blends

Experimental and kinetic studies on the blending of ethers or diesters with larger alkanes at low temperatures are enormously scarce. In this paper, the low-temperature oxidation (LTO) kinetics model of polyoxymethylene dimethyl ether 3 (OME3)/n-heptane (500 K∼950 K) was established by using the jet-stirred reactor (JSR) to conduct the LTO experiments of OME3/n-heptane with different blending ratios. GC/MS was used to detect and quantify 17 kinds of stable products in the LTO process of OME3/n-heptane. The detailed OME3/n-heptane kinetic model was fully verified experimentally. The interaction mechanism of OME3/n-heptane was discussed based on the experiments and corresponding chemical kinetic analysis. Results show that the oxidative decomposition processes of OME3 and n-heptane were significantly different, the LTO and NTC process of OME3 were significantly weaker than those of n-heptane, but the high-temperature reactivity of OME3 was much stronger. In addition, n-heptane significantly promoted the intermediate species CH3OCHO and COCOC*O of OME3, mainly because n-heptane significantly prolonged the LTO of OME3 in the fuel blends. And the NTC process of the fuel blends was mainly dominated by OME3, while the LTO process was more influenced by n-heptane, which resulted in the weakened NTC of n-heptane and the significantly enhanced LTO process of OME3.

A new insight into the key matrix components for aftertaste in Ampelopsis grossedentata (vine tea) infusion: From the intensity and duration of taste profiles using non-targeted metabolomics and molecular simulation

The aftertaste with a prolonged duration in ampelopsis grossedentata infusion (AGTI) is easily perceived, however, its formation mechanism is unclear. Therefore, aftertaste-A and richness were confirmed as the characteristic aftertaste of AGTI through sensory evaluation and electronic tongue. Moreover, 5-KETE, theobromine, etc., metabolites were identified as the differential components between AGTI and green tea infusion. Among them, p-coumaroyl quinic acid, xanthine etc., and proline, dihydromyricetin, etc., components contributed more to the formation of aftertaste-A and richness, respectively. Further, the bonding between characteristic metabolites for aftertaste in AGTI with their receptors were shown to be more stable using molecular docking, compared to metabolites related to typical taste profiles. The aftertaste in AGTI was more easily perceived by saltiness components or in NaCl system by molecular simulation. This study offers novel insight into the interaction mechanism of aftertaste in tea infusion and will contribute to further study on aftertaste for other foods.

Intrinsic resonance in gyrotron using non-resonant RF structure

Gyromonotrons are typically believed to rely on the convective interaction between the co-propagating beam and wave, with the extended energy-exchanging process stemming from the external feedback. However, numerous studies focusing on both transverse electric (TE) mode and transverse magnetic (TM) mode gyrotrons have consistently shown that beam–wave interactions in weak-feedback systems or even in uniform tubes without any structural feedback can yield a theoretical beam efficiency of more than 30% with major forward-wave output during near-cutoff operation, which is the typical operating condition for gyromonotrons. These intriguing findings raise questions about the actual feedback mechanism of gyromonotrons. In this article, comparative studies on the linear and nonlinear behaviors of uniform-tube gyrotron are investigated. The forward and backward waves are observed to co-generate and exhibit similar characteristics of ultra-slow group velocity under near-cutoff operation. This situation allows the as-generated forward wave to modulate the fresh beam, establishing a new backward-wave-like internal feedback loop. Additionally, the quasi-degenerate nature of the bi-directional propagating waves ensures their intrinsic in-phase relationship. The consequent constructive interference enables the uniform tube to function as a high-Q resonator. These findings are found to be independent of the choices of TE or TM modes, providing valuable insights into the underlying interaction mechanism of gyrotron devices.

The immobilization of cadmium by rape straw derived biochar in alkaline conditions: Sorption isotherm, molecular binding mechanism, and in-situ remediation of Cd-contaminated soil

The issue of cadmium (Cd) contamination in alkaline soils is escalating, necessitating the prompt implementation of effective passivation strategies. Biochar has gained significant attention for its potential in immobilizing heavy metals; however, the suitability of biochar as a remediation material and its micro-scale interaction mechanisms with Cd under alkaline conditions remain unclear. Rape straw (RS) were pyrolyzed at 400°C (RB400) and 700°C (RB700) to produce biochar. Adsorption and soil incubation experiments were carried out to assess the feasibility of using rape straw derived biochar pyrolyze at different temperatures and understanding their remediation mechanisms in alkaline environments. The sorption capacity for Cd immobilization was evaluated using sorption isotherms, revealing that RB700 exhibited enhanced Cd sorption performance with a maximum sorption capacity of 119.33 mg g-1 calculated from the Langmuir isotherm equation at pH 8. Cd L3-edge X-ray sorption near-edge structure (XANES) spectroscopy analysis confirmed that the dominant sorption species of Cd were organic Cd in RB400, with CdCO3 precipitation increased to 73.9% in RB700. Solid-state 13C nuclear magnetic resonance (13C-NMR) spectroscopy demonstrated that aromatic and carboxyl C functional groups are involved in the organic sorption of Cd through complexation and Cd2+-π interactions in alkaline solutions. The precipitation of CdCO3 in RB700 may resulted in a more effective passivation effect compared to RB400, leading to a significant 15.54% reduction in the DTPA-Cd content in Cd-contaminated soil. These findings highlight the effective Cd passivation Cd in alkaline environments by rape straw derived biochar, providing new molecular insights into the Cd retention mechanism of biochar. Furthermore, it presents novel ideas for improving remediation approaches for alkaline Cd-contaminated soils.

Both nanoplastic and iron mineral types determine their heteroaggregation: Aggregation kinetics and interface process

Nanoplastics (NPs) inevitably interact with iron minerals (IMs) after being released into aquatic environments, changing their transport and fate. In this study, batch heteroaggregation kinetics of four types of NPs, i.e., polymethyl methacrylate (PMMA), polystyrene (PS-Bare), amino-polystyrene (PS-NH2), and carboxyl-polystyrene (PS-COOH), with two different IMs (hematite and magnetite) were conducted. We found that the heteroaggregation of NPs and IMs and the associated interfacial interaction mechanisms are both NPs-dependent and IMs-dependent. Specifically, the NPs had stronger heteroaggregation with hematite than magnetite; the heteroaggregation order of two IMs with NPs was PMMA >PS-NH2 > PS-Bare > PS-COOH. Moreover, hydrogen bond, complexation, hydrophobic, cation-π, and electrostatic interaction were involved in the interfacial reaction between NPs and hematite, and electrons were transferred from the NPs to the hematite, causing the reduction of Fe3+ into Fe2+. Furthermore, we first revealed that both pre-homoaggregation of NPs and IMs could affect their subsequent heteroaggregation, and the homoaggregates of IMs could be interrupted by PMMA or PS-COOH NPs introduction. Therefore, the emerging NPs pollution is likely to generate an ecological effect in terms of elemental cycles such as iron cycle. This work provides new insights into assessing the environmental transfer and ecological effects of NPs in aquatic environments. Environmental ImplicationNanoplastics (NPs) are kinds of emerging contaminants. There are various NPs in the environment, and they will inevitably interact with natural iron minerals (IMs) after entering the water environment, affecting their environmental fate and risks. Herein, the aggregation kinetics experiments of different types of NPs and IMs were carried out, and the interfacial reactions and mechanisms were investigated using XPS and 2D-COS analysis. This work first revealed the effect of pre-homoaggregation of NPs or IMs on their heteroaggregation, providing new insights into the environmental behavior of emerged NPs and their ecological effects on iron cycle in natural aquatic environments.

Density and volume of adsorbed methane in key applications for in-situ gas content: Insights from molecular simulation

The evaluation of the in-situ gas content in deep coal seams, potentially containing free gas in saturated-oversaturated reservoirs, holds practical significance for exploration and production compared with shallow undersaturated-saturated reservoirs dominated by adsorbed gas. However, owing to the inherent limitations of volumetric and gravimetric methods, the accurate assessment of adsorbed and free gases faces significant challenges. In this study, based on molecular simulations, we focused on slit-shaped pores to explore the microscopic interaction mechanisms between coal and methane molecules under different pore sizes, temperatures, and pressures. By combining isothermal adsorption and pore structure experiments, the distribution characteristics of the adsorbed phase density (APD) and adsorbed phase volume (APV) were determined. The results showed that, in pores smaller than 1.5 nm, methane exhibited an aggregated state distribution (containing only adsorbed methane) characterized by micropore filling adsorption. In pores larger than 1.5 nm, methane showed a dispersed state distribution (coexistence of adsorbed and free methane) characterized by monolayer adsorption. The APD increased with pressure and decreased with temperature and pore size, whereas the APV remained independent of the pressure and temperature. In the in-situ gas content evaluation, three adsorption models (SL, SDR, and SL + SDR models) considering APV and APD were utilized to describe the methane adsorption behavior. The SDR model considering the APV was consistent with the actual physical properties and molecular simulation results. Traditional correction methods often lead to an overestimation of the adsorbed methane content, and neglecting the APV can result in an overestimation of the free methane content. In summary, the SDR model considering the APV can provide more rigorous scientific support for the refined study of methane occurrence states and gas content distribution.

Learning by design: Enhancing online collaboration in developing pre‐service TESOL teachers' TPACK for teaching with corpus technology

AbstractIn this study, we integrated corpus technology in pre‐service TESOL (Teaching English to Speakers of Other Languages) teachers' technological pedagogical content knowledge (TPACK) development in corpus technology, termed corpus‐based language pedagogy (CBLP), and highlighted the collaborative effort for knowledge building among participants for TPACK development. The study examined the role of online collaboration in facilitating how pre‐service TESOL teachers developed their CBLP (TPACK in corpus technology) using a learning‐by‐design approach, enacted it in co‐designing lessons, revised their lessons and reflected on their collective knowledge building processes. Using a case study approach involving 33 participants, the study focused on both intra‐ and inter‐group interactions to understand the pre‐service teachers' learning dynamics/changes and unpack the interaction mechanism involved in online collaborative learning. To these ends, we collected data including CBLP group lesson designs, intra‐group data (interviews) and inter‐group peer critical comments and analysed them based on the two stages (comprehension and transformation) of Shulman's pedagogical reasoning. The results suggest that engaging in online collaboration, facilitated by the learning‐by‐design approach, is instrumental in enabling pre‐service teachers to learn corpus technology and expand their repertoire of teaching strategies. Our findings imply that both intra‐ and inter‐group collaboration modes are important to help pre‐service TESOL teachers holistically develop TPACK for language teaching. Similar implications may be applied to other subject‐specific TPACK training.Practitioner notesWhat is already known about this topic Teacher preparation programmes play a crucial role in developing pre‐service teachers' technological, pedagogical, and content knowledge (TPACK) TPACK integration into pedagogical practice and subject‐specific professional development opportunities are important for effective teaching, but there is a lack of research on subject‐specific TPACK development (eg, TPACK in language teaching) Online collaborative learning can support TPACK development, but most studies focused on intra‐group interactions with little attention to inter‐group interactions What this paper adds Introduces a new corpus‐based language pedagogy (CBLP) for TESOL teachers to help them develop TPACK in language teaching Presents an innovative two‐step training framework for developing TESOL teachers' TPACK in corpus technology Examines the role of online collaboration in developing pre‐service TESOL teachers' TPACK for teaching with corpus technology through learning by design Provides in‐depth qualitative data analysed both qualitatively and quantitatively to investigate the specific roles that intra‐group and inter‐group interactions play in shaping pre‐service TESOL teachers' CBLP development Develops an analytical framework comprising nine categories (under the comprehension and transformation stages of Shulman's pedagogical reasoning model) to code pre‐service TESOL teachers' TPACK development in corpus technology Finds that intra‐group interactions facilitate both comprehension and transformation stages, while inter‐group interactions predominantly facilitate the transformation stage of CBLP Implications for practice Emphasises hands‐on corpus‐searching skills and guidance on browsing corpora when designing CBLP lessons Encourages both within‐group and between‐group interactions in online collaborative learning to foster TPACK development for using corpus technology in teaching language subjects Considers incorporating similar approaches for developing other subject‐specific TPACK for other teaching subjects

Inner-particle reaction mechanism of cellulose, hemicellulose and lignin during photo-thermal pyrolysis process: Evolution characteristics of free radicals

Based on the concentrated photo-thermal thermogravimetry analyzer (PT-TGA) reactor, the pyrolysis of the cellulose, hemicellulose and lignin with different ratios at 100 °C/min and 550–850 °C was performed. The interaction among the three components significantly reduced the reaction temperatures and increased the maximum weight loss rate. The cellulose/lignin interactions were the main reason for the increase of gas production, especially for the H2 production which reached 128.13 mL/g biomass, much higher than the calculated value of 75.35 mL/g biomass without considering the interactions. What occurred during the co-pyrolysis of cellulose/lignin was the combination of free radicals without consuming the hydrogen radicals, while the formation of chemicals in others’ interactions integrated with the hydrogen radicals inhibited the production of H2 at high temperatures. For full-component pyrolysis, the yield of C-containing gas can be calculated by adding a coefficient of interaction between two components, indicating that the effect of the three-component interaction was much lower than that of the two-component. This study established the interaction mechanism for the three components of biomass during photo-thermal pyrolysis based on free radicals.

Active element Ti improves the Sn-based alloy filler/graphite soldering interface: A combined first-principles and experimental study

Active element Ti plays a crucial role in the graphite soldering process. However, the atomic interaction mechanism between the active element Ti and graphite remains unclear. In this study, the enhancement effect of the active element Ti on the Sn-based alloy filler/graphite soldering interface was investigated by employing first-principles calculations combined with experimental methods. Based on the first-principles calculations, the adhesion work of the Sn/graphite interface models doped with two and four Ti atoms is 0.884 J/m2 and 1.896 J/m2, respectively, while that of the clean model is negative. Moreover, the segregation heat of the Sn/graphite interface model doped with more Ti atoms is more negative. All of these results indicate that Ti atoms doped at the Sn/graphite interface play a significant role in enhancing the interface. The electronic structures of the interface models with different numbers of titanium atoms were analyzed. The results revealed that the enhancement of the Sn/graphite interface was attributed to the transfer of electrons from the Ti-3d orbitals to the C-2p orbitals, leading to a strong interaction between the Ti and C atoms. The segregation of Ti was clearly observed at the Sn3·5Ag4Ti (Ce,Ga)/graphite soldering interface in the experiments, which was consistent with the results from the first-principles calculations. The shear strength of the Sn3·5Ag4Ti (Ce,Ga)/graphite soldered joint was tested, and an enriched region of titanium was found in the fracture surface on the graphite side. In addition, a tensile simulation was performed on the clean and Ti-doped Sn/graphite interfaces, and the results indicated that the Sn/graphite interface model enriched with Ti atoms had greater tensile simulation strength than that of the clean Sn/graphite interface model. These results further showed that Ti played a reinforcing role at the Sn/graphite interface. The results from our study provide a theoretical basis for exploring low-temperature active bonding methods in the packaging process of graphite connected to the heat dissipation surface of electronic devices.