Order Of Stability Research Articles

Stability of [10-12]cycloparaphenylene complexes with pristine fullerenes C76,78,84 and endohedral metallofullerenes M3N@C78,80.

[n]Cycloparaphenylenes ([n]CPPs) are strained macrocycles, comprising only sp2-hybridized carbon atoms. In recent years, [n]CPPs have become of great research interest in the field of supramolecular chemistry since their special structure enables the formation of novel host-guest complexes. In this work, we investigate the gas-phase chemistry of noncovalent complexes of [10-12]CPP with the pristine fullerenes C76/78/84 and the endohedral metallofullerenes (EMFs) Sc3N@D3h-C78, Sc3N@D5h-C80 and M3N@Ih-C80 (M = Sc, Y, Lu, Gd). The [1 : 1] complexes with [10-12]CPP are detected as radical cations. The stability and charge distributions of these complexes are studied using energy-resolved collision-induced dissociation (ER-CID). Our results assess the size complementarity, the influence of fullerene symmetry and size as well as the role of the metal size inside the EMF on the binding affinity and complex stability. Two main trends in complex stability have been found: First, [10-12]CPP form more stable complexes with EMFs than with pristine fullerenes and second, all complexes of EMFs with the C80 skeleton show similar stability despite the different metal clusters encapsulated. Another major finding is the fact that [11]CPP is generally the most suitable host for fullerenes with a C76/78/80/84 skeleton. Considering the charge distributions, we observe the existence of two different fragmentation channels for complexes with EMFs where the radical cation is either located at the CPP or at the EMF: (1) [n]CPP+˙ + EMF and (2) [n]CPP + EMF+˙. This behavior allows a clear distinction of the cage isomers ([11]CPP⊃Sc3N@Ih-C80)+˙ and ([11]CPP⊃Sc3N@D5h-C80)+˙ in the MS2 experiment. The experimental results are accompanied by density functional theory (DFT) calculations of ionization potentials (IPs) and fragmentation energies. The computational results fully confirm the measured order of complex stabilities and explain the prevalence of EMF or CPP signals in the spectra by the trend in ionization potentials.

Facile preparation of sodium alginate based hybrid material and its enhanced flame retardancy: Unravelling the role of silver phosphate

In this study, the sodium alginate/silver phosphate (NaAlg/Ag3PO4) hybrid materials were prepared in-situ, and the composites were characterized by X-ray diffractometry, X-ray photoelectron spectroscopy, scanning electron microscopy, and Fourier transform infrared spectrum. To investigate flame-retardant properties of NaAlg/Ag3PO4 and the phosphorus-polymetallic flame-retardant effects, the combustion behavior and flammability of the composites were assessed via the thermogravimetric analysis, limiting oxygen index (LOI) and micro-calorimeter tests (MCC). The results show that the LOI of NaAlg/Ag3PO4 was 52.3%, which was upgraded from flammable material to flame retardant material, compared to 18.5% of NaAlg, and the heat release capacity (HRC) of NaAlg/Ag3PO4 was 37 J/(g·K), which was reduced by 66.7% compared with that of pristine NaAlg, and the fire safety performance was also consistent with the order of thermal stability. By using the thermogravimetric analysis coupled with Fourier transform infrared analysis (TG-FTIR) and pyrolysis-gas chromatography–mass spectrometry (Py-GC/MS), the flame retarding mechanism of the NaAlg/Ag3PO4 and the role of Ag3PO4 in the material were proposed based on the experimental data.

In-Silico Evaluation of Deoxyvasicinone and Semi Synthetic derivatives of Justicia adhatoda against Coronavirus

Novel coronavirus disease (COVID-19) is the major health crisis in the world. World Health Organization has declared COVID-19 as a global pandemic. There are no effective drugs to treat COVID-19 infection. Some drugs include remdesivir, umifenovir, favipiravir, lopinavir/ ritonavir, ribavirin, hydroxychloroquine, etc are used to treat this disease. There is an urgent need for public health measures to implement preventive approaches to control severe COVID-19 disease. Justica adhatoda is a well-known plant drug in Ayurvedic and Unani medicines. Various phytochemical constituents have been isolated from J. adhatoda which possesses activities like antitussive, abortifacient, antimicrobial, cardiovascular protection, anticholinesterase, anti-inflammatory and other important activities. The alkaloids from leaf extracts of J. adhatoda possess anti-viral activity. Molecular docking interaction study against 6W63 showed that molecule 4d showed maximum docking interaction with dock score of (-) 8.1 kcal/mol. MD simulation data reflected the stable ligand-receptor interaction. Maximum and minimum energy gap were showed by 7 and 4d, respectively. The order of stability of the synthesized molecules were 4d>2>3>5>4c>4a>4b>1>6>7. The order of ionization potential and electron affinity of the synthesized molecules were 3>4c>4b>4a>1>6>7>4d>5>2. These data confirmed that molecule 4d would be a boon for society.

Cage-rearranged and cage-intact syntheses of azido-functionalized larger T10 and T12 POSSs.

Herein, we investigate the product type and distribution during the synthesis of azido-functionalized larger polyhedral oligomeric silsesquioxanes (POSSs) using 3-chloropropyl- and chloromethyldimethylsilylethyl-functionalized T8, T10, and T12 POSSs as precursors. Our findings indicate that cage rearrangement occurs for the 3-chloropropyl-functionalized POSS cages with a stability order of T12 > T10 > T8, while the chloromethyldimethylsilylethyl-functionalized POSS cages remain structurally intact after the nucleophilic substitution.

Enhancing Enzyme Stability and Functionality: Covalent Immobilization of Trypsin on Magnetic Gum Arabic Modified Fe3O4 Nanoparticles.

This study aimed to fabricate gum Arabic (GA)-coated Fe3O4 nanoparticles bearing numerous active aldehyde groups on their surface, followed by an assessment of their capability as a magnetic support for the covalent immobilization of the trypsin enzyme for the first time. FT-IR, XRD, TGA, and SEM results demonstrated the successful synthesis of GA-coated Fe3O4 nanoparticles, along with the covalent immobilization of the enzyme onto the support. Immobilization enhanced the relative enzymatic activity across a range of aqueous solution pH levels (ranging from 4 to 11) and temperatures (ranging from 20 to 80 °C) without altering the optimum pH and temperature for trypsin activity. Kinetic studies using Michaelis-Menten plots revealed changes in kinetic parameters, including a lower Vmax and higher Km for immobilized trypsin compared to the free enzyme. The immobilization onto magnetic gum Arabic nanoparticles resulted in an improved stability of trypsin in the presence of various solvents, maintaining a stability order comparable to that of the free enzyme due to the stabilizing effect of the support. The reusability results showed that the immobilized enzyme can retain over 93% of its activity for up to 15 cycles.

Including protein hydrolysates during thermal processing mitigates the starch digestion of resulted starch-based binary matrix

Staple foods with starch and protein components are usually consumed after thermal processing. To date, how including protein hydrolysates (with varied hydrolysis degrees) tailors the structure and digestion features of starch-based matrix with thermal processing has not yet been sufficiently understood. Here, corn starch (CS), soy protein isolate (SPI), and soy protein isolate hydrolysates (SPIH) with different hydrolysis time (5–60 min) were used to prepare starch-based binary matrices. With the addition of SPI or SPIH during thermal processing, the resultant binary systems exhibited higher thermal stability (breakdown visibility was increased by 1.9–10.8 times), denser networks, and fewer short-range orders (R995/1022 was decreased by up to 15.3 %). These structural changes allowed an inhibited starch digestion within the binary system, especially with increased SPI or SPIH content. Compared with CS, the content of resistant starch (RS) for CS-SPI binary complex (10:3 w/w) increased from 9.89 % to 16.69 %. Compared to SPI, SPIH inclusion displayed a stronger inhibitory effect on starch digestion since the reduced molecule size of SPIH probably enhanced its interplays with starch or amylase. For instance, the 10:3 w/w starch-SPIH 60 binary matrix possessed the highest RS content (19.07 %).

Feasibility Study of Amadori Rearrangement Products of Glycine, Diglycine, Triglycine, and Glucose as Potential Food Additives for Production, Stability, and Flavor Formation.

Amadori rearrangement products (ARPs), as intermediates of the Maillard reaction (MR), are potential natural flavor additives but there is a lack of investigation especially in oligopeptide-ARPs. This study for the first time conducted a systematic analysis in comparing ARPs of glycine, diglycine, triglycine, and glucose to corresponding classic MR systems, including production, stability, and flavor analysis. The ARPs were effectively produced by prelyophilization with heating at 70 °C for 60 min and purified to 96% by a two-step purification method. Correlated with the stability order of amino compounds (glycine > diglycine > triglycine), the stability order of ARPs was Gly-ARP > Digly-ARP ≈ Trigly-ARP. In a negative correlation with heating temperature and time, ARPs were less stable than original amino compounds at high temperatures (100, 130, and 160 °C). ARPs exhibited better flavor formation ability in pyrazines and furans than MR systems, with similar flavor compositions but different preferences. Diglycine- and triglycine-ARPs exhibited better flavor formation efficiency than glycine-ARP. Heating temperature and time, initial pH, and carbon chain length were found to be the parameters that affect the stability and flavor formation of ARPs. This study suggested that ARPs, especially peptide-ARPs, have great potential for usage as food flavor additives in the future.

Overcoming Radical Stability Order via DABCO-Triggered Desulfurization: Visible-Light-Promoted 1,2,4-Trifunctionalization of Butenyl Benzothiazole Sulfone with Thiosulfonate.

A radical 1,2,4-trifunctional reaction of thiosulfonate to unactivated olefin is achieved by a migration strategy under mild conditions. In this reaction, the more unstable primary free radicals are in situ generated after the migration of heteroaryl groups in the presence of DABCO. This trifunctionalization of unactivated olefins involves two C-S bond formations and one C-C bond formation.

Thermal decomposition kinetics and mechanisms of long alkyl chain ionic liquids with carboxylate anions

This work presents the synthesis and analysis of the thermal decomposition kinetics and mechanisms of long alkyl chain ionic liquids (ILs) with cations 1-decyl-3-methylimidazolinium ([C10MIM]+), 1-dodecyl-3-methylimidazolinium ([C12MIM]+), and 1-hexadecyl-3-methylimidazolinium ([C16MIM]+) and butanoate ([C3COO]−) and heptanoate ([C6COO]−) anions. The kinetics analysis was performed using the Kissinger-Akahira-Sunose isoconversional methodology. The results indicated that the carboxylate ILs are less thermally stable than their bromide analogues and the order of thermal stability was explained by the values of the kinetic parameters (Ea and lnA) and their variation with α. For most of the studied carboxylate ILs there was a considerable variation in Ea as the decomposition progressed, indicating multiple decomposition steps. The thermal decomposition mechanism was studied by analyzing the thermal degradation residue from 1H NMR spectroscopy.

Assessing biochar's permanence: An inertinite benchmark

The natural removal of carbon dioxide and its permanent storage by the Earth system occurs through (i) inorganic carbon and (ii) organic carbon pathways. The former involves the “mineralization” of carbon and formation of carbonate minerals, whereas the latter employs the “maceralization” or natural carbonization of biomass into the “inertinite maceral”. The production of biochar is a carbon dioxide removal (CDR) method that imitates the geological organic carbon pathway, using controlled pyrolysis to rapidly carbonize and transform biomass into inertinite maceral for permanent storage. Therefore, the main challenge in assessing biochar's permanence is to ensure complete transformation has been achieved.Inertinite is the most stable maceral in the Earth's crust and is hence considered an ultimate benchmark of organic carbon permanence in the environment. Therefore, this study aims to measure the degree of biochar's carbonization with respect to the well-established compositional and microscopic characteristics of the inertinite. The random reflectance (Ro) of 2% is proposed as the “inertinite benchmark” (IBRo2%) and applied to quantify the permanent pool of carbon in a biochar using the Ro frequency distribution histogram. The result shows that 76% of the studied commercial biochar samples have their entire Ro distribution range well above IBRo2% and are considered pure inertinite biochar. The oxidation kinetic reaction model for a typical inertinite biochar indicates a time frame of approximately 100 million years for the degradation and loss of half of the carbon in the biochar. This estimate assumes exposure to a highly oxidizing environment with a constant surface temperature of 30°C, highlighting the inherent “permanent” nature of the material. In a less hostile environment, the expected permanence of inertinite is generally anticipated to be even longer.In addition to the inertinite that constitutes the largest fraction of the typical commercial biochar, an incompletely carbonized biochar may contain up to three other organic pools in descending order of stability. The relative concentration of these pools in a biochar can be quantified by a combination of geochemical pyrolysis and random reflectance methods. Furthermore, the Ro can be used to calculate the carbonization temperature (CT oC) of a biochar, which is the maximum temperature to which biochar fragments have been exposed during pyrolysis. This indicator provides important information about the efficiency of the carbonization process and subsequently the biochar's stability, with respect to production temperature (PT oC), heating residence time, and thermal diffusivity. Short summaryThe Earth's carbon dioxide removal and storage occur via inorganic and organic pathways: mineralization and maceralization. Biochar, imitating the organic pathway, undergoes controlled pyrolysis to transform biomass feedstock through a carbonization process into the inertinite maceral, which is a permanently stable form of organic carbon. Kinetic modeling in this study confirms inertinite's carbon stability over geological time scale.Assessing biochar's permanence hence hinges on achieving complete carbonization and transformation. Inertinite serves as the gold standard for organic carbon permanence, guiding this study to measure biochar's carbonization against inertinite characteristics. Analyzing the random reflectance (Ro) of biochar reveals that 76% of studied samples qualify as pure inertinite. Apart from inertinite, other organic pools in biochar, quantifiable through geochemical pyrolysis and Ro methods, affect stability. Determining the carbonization temperature offers insights into biochar's efficiency and stability concerning production variables.

Exonic splicing code and coordination of divalent metals in proteins.

Exonic sequences contain both protein-coding and RNA splicing information but the interplay of the protein and splicing code is complex and poorly understood. Here, we have studied traditional and auxiliary splicing codes of human exons that encode residues coordinating two essential divalent metals at the opposite ends of the Irving-Williams series, a universal order of relative stabilities of metal-organic complexes. We show that exons encoding Zn2+-coordinating amino acids are supported much less by the auxiliary splicing motifs than exons coordinating Ca2+. The handicap of the former is compensated by stronger splice sites and uridine-richer polypyrimidine tracts, except for position -3 relative to 3' splice junctions. However, both Ca2+ and Zn2+ exons exhibit close-to-constitutive splicing in multiple tissues, consistent with their critical importance for metalloprotein function and a relatively small fraction of expendable, alternatively spliced exons. These results indicate that constraints imposed by metal coordination spheres on RNA splicing have been efficiently overcome by the plasticity of exon-intron architecture to ensure adequate metalloprotein expression.

A DFT study on the switching energy of multiferroic capacitor with stable single-phase multiferroic material

In spintronic technology, bismuth ferrite BiFeO3 (BFO) is a potential multiferroic material for multiferroic capacitor application. In present study, the impact of transition metals X = Co, Ni, Mn, Ti at the Fe-site and rare earth element lanthanum (La) at the Bi-site is investigated using DFT calculation in order to improve the structural stability, spin polarized electronic, and dielectric properties of bismuth ferrite for switching energy of multiferroic capacitor applications. The calculations are carried out in the Cambridge Serial Total Energy Package (CASTEP) code by using ultra-soft pseudopotential (USP). The substitution of La and X atoms alters the spin-polarizedelectronic and dielectric characteristics of BFO, leading to an increase in the density of states (DOS) around the Fermi level. The observed descending order of the structure stability of co-doped BFO is given as: LaCo > LaNi > LaMn co-doped BFO system. LaCo and LaNi co-substituted systems have shown high spin polarizations of 87.08 % and 82.20 % respectively. Low switching energies of 0.52 aJ and 0.72 aJ, respectively have been observed for LaCo and LaNi co-doped BFO systems for multiferroic RAM capacitor applications.

Integrated Circular Economy Model System for Direct Lithium Extraction: From Minerals to Batteries Utilizing Aluminum Hydroxide.

Aluminum hydroxide, an abundant mineral found in nature, exists in four polymorphs: gibbsite, bayerite, nordstrandite, and doyleite. Among these polymorphs gibbsite, bayerite, and commercially synthesized amorphous aluminum hydroxide have been investigated as sorbent materials for lithium extraction from sulfate solutions. The amorphous form of Al(OH)3 exhibits a reactivity higher than that of the naturally occurring crystalline polymorphs in terms of extracting Li+ ions. This study employed high-temperature oxide melt solution calorimetry to explore the energetics of the sorbent polymorphs. The enthalpic stability order was measured to be gibbsite > bayerite > amorphous Al(OH)3. The least stable form, amorphous Al(OH)3, undergoes a spontaneous reaction with lithium, resulting in the formation of a stable layered double hydroxide phase. Consequently, amorphous Al(OH)3 shows promise as a sorbent material for selectively extracting lithium from clay mineral leachate solutions. This research demonstrates the selective direct extraction of Li+ ions using amorphous aluminum hydroxide through a liquid-solid lithiation reaction, followed by acid-free delithiation and relithiation processes, achieving an extraction efficiency of 86%, and the maximum capacity was 37.86 mg·g-1 in a single step during lithiation. With high selectivity during lithiation and nearly complete recoverability of the sorbent material during delithiation, this method presents a circular economy model. Furthermore, a life cycle analysis was conducted to illustrate the environmental advantages of replacing the conventional soda ash-based precipitation process with this method, along with a simple operational cost analysis to evaluate reagent and fuel expenses.

High-permittivity Solvents Increase MXene Stability and Stacking Order Enabling Ultraefficient Terahertz Shielding.

2Dtransition metal carbides and nitrides (MXenes) suggest an uncommonly broad combination of important functionalities amongst 2D materials. Nevertheless, MXene suffers from facile oxidation and colloidal instability upon conventional water-based processing, thus limiting applicability. By experiments and theory, It is suggested that for stability and dispersibility, it is critical to select uncommonly high permittivity solvents such as N-methylformamide (NMF) and formamide (FA) (εr =171, 109), unlike the classical solvents characterized by high dipole moment and polarity index. They also allow high MXene stacking order within thin films on carbon nanotube (CNT) substrates, showing very high Terahertz (THz) shielding effectiveness (SE) of 40-60dB at 0.3-1.6 THz in spite of the film thinness <2µm. The stacking order and mesoscopic porosity turn relevant for THz-shielding as characterized by small-angle X-ray scattering (SAXS). The mechanistic understanding of stability and structural order allows guidance for generic MXene applications, in particular in telecommunication, and more generally processing of 2D materials.

Inverse scattering transform algorithm for the Manakov system

A numerical algorithm is described for solving the inverse spectral scattering problem associated with the Manakov model of the vector nonlinear Schrödinger equation. This model of wave processes simultaneously considers dispersion, nonlinearity and polarization effects. It is in demand in nonlinear physical optics and is especially perspective for describing optical radiation propagation through the fiber communication lines. In the presented algorithm, the solution to the inverse scattering problem based on the inversion of a set of nested matrices of the discretized system of Gelfand–Levitan–Marchenko integral equations, using a block version of the Levinson-type Toeplitz bordering algorithm. Numerical tests carried out by comparing calculations with known exact analytical solutions confirm the stability and second order of accuracy of the proposed algorithm. We also give an example of the algorithm application to simulate the collision of a differently polarized pair of Manakov optical vector solitons.

NORMATIVE ISLAMIC CONCEPTUALIZATIONS OF FAMILIES AND KINSHIP THROUGH MAQASID PERSPECTIVES: A COMPREHENSIVE LITERATURE STUDY

The current article represents a comprehensive understanding of the family system and kinship in normative Muslim scholarship. It introduces the perception and definition of family and kinship relations and presents some of its fundamental features and bases in order to restructure critical, yet scattered opinions of scholars from various religious, legal, and historical Islamic sources. This research also aims to investigate numerous normatively formed perspectives related to family forms, the paradigm of values for family and kinship, and the family systems inspired by normative sources of Islam which have been discussed in broader discourse echelons to show the development of Muslim scholarship, provisions, opinions, and analysis, with regard to family and kin, especially under the umbrella of maqāṣid al-shari’ah. The article follows a qualitative methodology with historical, analytical, and descriptive approaches in a comparative manner when investigating normative accounts of the Muslim family and kinship. This study's contribution to international scholars in the field lies in its comprehensive analysis of maqasid framework for family and kinship in Islam and its divergence among normative scholarship. By shedding light on these normative perspectives, it enriches the existing scholarly discourse on maqasid al-shari’ah and opens up new avenues for further research and exploration in contemporary approaches to family and kinship studies. The findings of this study provide valuable insights for researchers, academics, and practitioners seeking a deeper understanding of maqasid al-shari’ah and its practical applications in contemporary contexts. The article found out that the advent of Islam, as mentioned in normative Muslim scholarship, introduced several religious rudiments into the family and kinship life that morally, structurally, and socially altered and regulated the character, structure, and purposes of the Muslim family to ensure stability and advocate social relations and order.

Production of Polyurethane Elastomers from Ximenia americana L (Wild Olive) Seed Oil and Diisocyanates

Seed oils readily undergo derivatization by alcoholysis to yield biodegradable polyols and Ximenia americana plant from the family of Olacaeae has oily seeds. Hence, the objective of this paper is to assess the production of polyurethane elastomers from Ximenia americana L (Wild Olive) Seed Oil with diisocyanates, namely, hexamethylene diisocyanate (HDI), toluene diisocyanate (TDI) and 4,4’-methylene diphenyl diisocyanate (MDI) respectively using standard procedure and characterized by Fourier-Transform Infrared Spectroscopy (FTIR), Instron Tensile Testing Machine and Thermogravimetric Analyzer (TGA). The tensile strength and tensile modulus for HDI-based polyurethane elastomers, 5.83±0.15 and 3.95±0.07 MPa respectively are higher than the corresponding ones for TDI- and MDI-based polymers. This is consistent with the highest crosslink density (γ) of 5.05×10-3 for HDI-based polymer with corresponding average molecular weight between crosslinks (Mc) of 197.87 gmol-1 The polyurethane elastomers are stable up to 250-265oC with order of stability: HDPU-1.50&gt;MDPU-1.50&gt;TDPU-1.50. The results showed that diol from Ximenia americana seed oil is effective for production of polyurethane elastomers with properties which are comparable to ones of the non-oil-based polymers.

Exploration of novel structures and related physical properties of Fe2Pt ordered alloys

The Fe–Pt phase diagram suggests the possible existence of ordered Fe2Pt structures, however, the ordered structures of Fe2Pt and related physical properties are unclear until now. In this work, four new low-energy ferromagnetic Fe2Pt ordered structures are predicted based on the particle swarm optimization algorithm. Their structural stability is verified by the formation enthalpy, mechanical stability and lattice dynamic stability. The order of the thermodynamic stability is Cmcm > Immm > I4/mmm > P3¯m1. All four structures are dynamically (except tetragonal I4/mmm structure) and mechanically stable. The fundamental physical properties including magnetic, elastic, phonon and thermal properties are investigated in detail. Their total magnetic moments, as well as the bulk modulus are almost the same. The shear modulus and Young's modulus of Cmcm structure are close to the P3¯m1, and larger than that of other two structures. The order of the elastic anisotropy is Immm > P3¯m1 > I4/mmm > Cmcm. The orthorhombic Immm structure can be regarded as a distorted tetragonal I4/mmm structure, and the distortion effectively improves the physical properties of the I4/mmm structure. The thermal properties at finite temperatures show that the trigonal P3¯m1 structure is more suitable for high-temperature applications compared to other structures. The results of linear thermal expansion coefficient indicate that anisotropy order of thermal expansion is Immm > I4/mmm > Cmcm > P3¯m1. More interesting is the discovery of the Invar effect along the y-axis direction in orthorhombic Immm structure.

Adsorption and dissociation of CH3SH on FeS surface: A DFT study

Methyl mercaptan (CH3SH) is a common sulfide in oil and natural gas, easily corroded in transportation pipes and storage containers. In this paper, the adsorption and dissociation processes of CH3SH on FeS (0 0 1), (0 1 1), (1 0 0) and (1 1 1) surfaces have been studied by the density functional theory (DFT). And the characteristics of the adsorption and dissociation processes were elucidated. The calculated surface energies show that the order of surface stability is (0 0 1) > (0 1 1) > (1 0 0) > (1 1 1). The stability of CH3SH adsorption is (1 1 1) > (1 0 0) > (0 1 1) > (0 0 1) by the adsorption energy, and the most stable adsorption configurations are obtained. Compared with the changes in electron density and the partial density of states (PDOS) before and after adsorption, there is an obvious electron orbital hybrid phenomenon between CH3SH and FeS (1 0 0), (1 1 1) surface, and its adsorption is stronger than that of the other two surfaces. It can be seen from the calculation of the transition state that the dissociation reaction of CH3SH is endothermic on the (0 0 1) and (0 1 1) surfaces, while the exothermic reaction on the (0 1 1) and (0 0 1) surfaces. CH3SH will dissociate preferentially on the FeS (1 0 0) surface because the reaction of Ea and ΔE on this surface is the smallest. Overall, the adsorption and dissociation processes are exothermic, the increase in temperature makes the crystal surface unstable and susceptible to spontaneous combustion, and the phenomenon occurs first on the FeS (1 0 0) and FeS (1 1 1) surfaces. These findings increase the understanding of the electronic structure and energy of the sulfides' action on the FeS surface and also have a reference value for flame retardant research.

The interface bonding properties of Mg/SiC composite doped with Zr, Al, and Zn elements: A first-principles study

In order to improve the mechanical properties of silicon carbide composite materials based on magnesium, Zr, Al, and Zn are frequently utilized as alloying elements. The mechanical properties of the composite material are closely related to the interface bonding strength. Theoretical calculations on the impact of adding components on the strength of the interface bonding are currently not thorough enough. In this work, the first-principles calculations are performed to investigate the impact of doping Zr, Al, and Zn elements in the Mg matrix on the interface bonding of 6 H-SiC/Mg and the effect of alloy elements on the interface stability and electronic structure in composite interfaces. The results showed that Al and Zn elements may segregate from the interface in the form of a second phase, whereas Zr elements are difficult to segregate from the Mg/SiC composite interface. Zr tends to increase the stability of the Mg/SiC composite interface over the full range of ∆μSi, whereas Al and Zn tend to weaken it. In addition, the stability order of the doped interface is Zr>Al>Zn. The electronic structure of the doping interface shows that the bonding at the interface is both ionic and covalent. The segregation behavior of doped elements at the interface and the variation in covalent bonding strengths between interfaces are the primary variables impacting interface bonding. The internal cleavage layer of the composite material's adhesion work can be examined to reveal that the composite interface is not the material's probable fracture failure point.