Diffraction Experiments Research Articles

Syntheses and Conformations of a Trinuclear Gold(I) System Based on a Triethinyl‐trisilacyclohexane Scaffold

AbstractTrisilacyclohexanes and bissilylmethanes with acetylene units attached to silicon sites have been converted into tri‐ and di‐nuclear gold(I)phosphane complexes and characterized by NMR spectroscopy and X‐ray diffraction. The bissilylmethane‐based gold complexes were used as a test system to work out the synthetic routes before transferring them to the trisilacyclohexane scaffolds, because the latter are more difficult to access. The occurrence of aurophilic interactions (short Au ⋅ ⋅ ⋅ Au contacts) depends on the steric bulk of the phosphorus‐bonded alkyl and aryl groups. DFT studies show that dispersion effects play an important role in the ability to form intramolecular Au ⋅ ⋅ ⋅ Au interactions. QTAIM analyses show that a subtle change of the steric bulk of the phosphane groups alters the relative strength of the dispersion and aurophilic interactions. The combination of DFT studies and X‐ray diffraction experiments shows that the conformation of the trisilacyclohexane backbone is also phase dependent.

Prediction of photodynamics of 200nm excited cyclobutanone with linear response electronic structure and abinitio multiple spawning.

Simulations of photochemical reaction dynamics have been a challenge to the theoretical chemistry community for some time. In an effort to determine the predictive character of current approaches, we predict the results of an upcoming ultrafast diffraction experiment on the photodynamics of cyclobutanone after excitation to the lowest lying Rydberg state (S2). A picosecond of nonadiabatic dynamics is described with abinitio multiple spawning. We use both time dependent density functional theory (TDDFT) and equation-of-motion coupled cluster singles and doubles (EOM-CCSD) theory for the underlying electronic structure theory. We find that the lifetime of the S2 state is more than a picosecond (with both TDDFT and EOM-CCSD). The predicted ultrafast electron diffraction spectrum exhibits numerous structural features, but weak time dependence over the course of the simulations.

Critical assessment of the x-ray restrained wave function approach: Advantages, drawbacks, and perspectives for density functional theory and periodic abinitio calculations.

The x-ray restrained wave function (XRW) method is a quantum crystallographic technique to extract wave functions compatible with experimental x-ray diffraction data. The approach looks for wave functions that minimize the energies of the investigated systems and also reproduce sets of x-ray structure factors. Given the strict relationship between x-ray structure factors and electron distributions, the strategy practically allows determining wave functions that correspond to given (usually experimental) electron densities. In this work, the capabilities of the XRW approach were further tested. The aim was to evaluate whether the XRW technique could serve as a tool for suggesting new exchange-correlation functionals for density functional theory or refining existing ones. Additionally, the ability of the method to address the influences of the crystalline environment was also assessed. The outcomes of XRW computations were thus compared to those of traditional gas-phase, embedding quantum mechanics/molecular mechanics, and fully periodic calculations. The results revealed that, irrespective of the initial conditions, the XRW computations practically yield a consensus electron density, in contrast to the currently employed density functional approximations (DFAs), which tend to give a too large range of electron distributions. This is encouraging in view of exploiting the XRW technique to develop improved functionals. Conversely, the calculations also emphasized that the XRW method is limited in its ability to effectively address the influences of the crystalline environment. This underscores the need for a periodic XRW technique, which would allow further untangling the shortcomings of DFAs from those inherent to the XRW approach.

Using the Autoproc Toolkit for Data Processing and Analysis

A typical diffraction experiment yields several pictures and datasets from various crystals within ‎a brief timeframe. This poses a barrier for the efficient operation of advanced synchrotron ‎beamlines and the following data processing. Novice users, in particular, may have a sense of ‎being inundated by the tables, graphs, and numerical information that is provided to them via ‎different data-processing systems and software packages. Here, we outline many common ‎obstacles that users face while processing a collection of photos to generate a processed dataset. ‎Our main emphasis is on the challenges that often occur while transitioning from the earliest ‎phases of converting experimental data collecting into an interpreted electron density model. ‎Examining certain data properties during processing may frequently help solve or identify ‎challenges such as unforeseen crystal formations, issues with crystal manipulation, and ‎suboptimal selection of data-collection techniques. Ultimately, it is important to distinguish ‎between concerns that are beyond of one's immediate control after the experiment has concluded ‎and those that can be dealt with later.‎ Presenting auto PROC, an innovative software solution ‎that combines external processing packages with new tools and an automated workflow script. ‎This program is designed to help users effectively handle data that is impacted by the issues ‎outlined above. It specifically focuses on automating the processing of multi-sweep data sets ‎produced from multi-axis gonio metrics. It offers consumers both instruction and important ‎insights into the processing of data that is not done online.‎

Disorder induced band gap lowering in kesterite type Cu2ZnSnSe4 and Ag2ZnSnSe4: a first-principles and special quasirandom structures investigation

Quaternary chalcogenides, i.e. Cu2ZnSnS4, crystallising in the kesterite crystal structure have already been demonstrated as potential building blocks of thin film solar cells, containing only abundant elements and exhibiting power conversion efficiencies of about 14.9% so far. However, due to the potential presence of several structurally similar polymorphs, the unequivocal identification of their ground state crystal structures required the application of more elaborate neutron diffraction experiments. One particular complication arose from the later identified Cu–Zn disorder, present in virtually all thin film samples. Subsequently, it has been shown experimentally that this unavoidable Cu–Zn disorder leads to a band gap lowering in the respective samples. Additional theoretical investigations, mostly based on Monte-Carlo methods, tried to understand the atomistic origin of this disorder induced band gap lowering. Here, we present theoretical results from first-principles calculations based on density functional theory for the disorder induced band gap lowering in kesterite Cu2ZnSnSe4 and Ag2ZnSnSe4, where the Cu–Zn and Ag–Zn disorder is modelled via a supercell approach and special quasirandom structures. Results of subsequent analyses of structural, electronic, and optical properties are discussed with respect to available experimental results, and will provide additional insight and knowledge towards the atomistic origin of the observed disorder induced band gap lowering in kesterite type materials.

Hybrid Metal Oxide (Ag-ZnO) Impregnated Biocomposite in the Development of an Eco-Friendly Sustainable Film.

Nanotechnology offers an innovative application as an eco-friendly food packaging film fabricated along with a degradable active mixture (AM). The AM is an assortment of alloyed metal oxide nanoparticles (Ag-ZnO), citron powder (AA), and Curcuma peel powder (CPP). Alloyed nanoparticles (NPs) were observed to exhibit a hexagonal structure from the experimental X-ray diffraction. Compositional and morphological study of the NPs (22.69 nm) and AM (32 nm) was done using energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and ζ- potential was observed to be -14.7 mV, indicating the stability of NPs. The prepared film was observed to be more effective with antibacterial analysis against Escherichia coli, exhibiting 72% of inhibition and antioxidant activity with IC50: 51.56% using the 2,2 diphenyl-1-picrylhydrazyl (DPPH) assay. Film 1, Film 2, Film 3, and Film 4 were fabricated with the AM and observed to be perfectly encapsulated by PVA using XRD. FESEM images of the film exhibit the aggregation of NPs with biocomposites in perfect distribution. The mechanical properties such as Young's modulus, elongation at break, tensile strength, and ultimate tensile strength (UTS- 5.37 MPa) were experimented for the films. The degradation rate was observed to be 6.12% for film 1 using the soil burial method. The study emphasizes that NPs along with biocomposite upgrade the sustainability of the packaging film with improved mechanical and physicochemical properties. The synthesized film with biomaterials could be used as a "green" food package to store fruits, vegetables, and sweets in the food industry.

Reverse Separation of Carbon Dioxide and Acetylene in Two Isostructural Copper Pyridine‐Carboxylate Frameworks

AbstractSeparating acetylene from carbon dioxide is important but highly challenging due to their similar molecular shapes and physical properties. Adsorptive separation of carbon dioxide from acetylene can directly produce pure acetylene but is hardly realized because of relatively polarizable acetylene binds more strongly. Here, we reverse the CO2 and C2H2 separation by adjusting the pore structures in two isoreticular ultramicroporous metal–organic frameworks (MOFs). Under ambient conditions, copper isonicotinate (Cu(ina)2), with relatively large pore channels shows C2H2‐selective adsorption with a C2H2/CO2 selectivity of 3.4, whereas its smaller‐pore analogue, copper quinoline‐5‐carboxylate (Cu(Qc)2) shows an inverse CO2/C2H2 selectivity of 5.6. Cu(Qc)2 shows compact pore space that well matches the optimal orientation of CO2 but is not compatible for C2H2. Neutron powder diffraction experiments confirmed that CO2 molecules adopt preferential orientation along the pore channels during adsorption binding, whereas C2H2 molecules bind in an opposite fashion with distorted configurations due to their opposite quadrupole moments. Dynamic breakthrough experiments have validated the separation performance of Cu(Qc)2 for CO2/C2H2 separation.

Continuous Strain Regulation of Palladium-Gold at the Atomic Level.

Revealing the effect of surface structure changes on the electrocatalytic performance is beneficial to the development of highly efficient catalysts. However, precise regulation of the catalyst surface at the atomic level remains challenging. Here, we present a continuous strain regulation of palladium (Pd) on gold (Au) via a mechanically controllable surface strain (MCSS) setup. It is found that the structural changes induced by the strain setup can accelerate electron transfer at the solid-liquid interface, thus achieving a significantly improved performance toward hydrogen evolution reaction (HER). In situ X-ray diffraction (XRD) experiments further confirm that the enhanced activity is attributed to the increased interplanar spacing resulting from the applied strain. Theoretical calculations reveal that the tensile strain modulates the electronic structure of the Pd active sites and facilitates the desorption of the hydrogen intermediates. This work provides an effective approach for revealing the relationships between the electrocatalyst surface structure and catalytic activity.

Revisiting the thermodynamic properties of the ZrCr2 Laves phases by combined approach using experimental and simulation methods

A comprehensive study of ZrCr2 Laves phases is important for both fundamental research and technological applications. The ZrCr2 compound is a typical precipitate observed in Zr-based alloys including the newly developed Cr-coated Zr cladding known as Accident Tolerant Fuel cladding. The brittle behavior of the Laves phases and the low melting point at the interface zone between the precipitates and the Zr matrix are considered as governing the thermomechanical behaviors of these newly developed nuclear fuel claddings for normal operating conditions but more dramatically in case of Loss Of Coolant Accident (LOCA) conditions. The aim of the present study is to investigate the various ZrCr2 Laves polymorphs and their thermodynamic features particularly where conflicts exist in the literature. Based on diffraction experiments of annealed samples, it has been established that the transformation from the C14 high-temperature form to the C15 low-temperature form is of displacive nature without the C36 polymorph forming as an intermediate phase. The stable and metastable domains of C14 and C15 and their thermodynamic properties have been determined. The specific heat of both C14 and C15 types was measured over a wide range of temperatures from 2 to 1063 K by coupling relaxation calorimetry and DSC. The experimental data were fitted using a modified Einstein model. The room temperature entropies of the C14 and C15 phases were evaluated. The enthalpy of formation was measured for the first time using drop solution calorimetry in liquid Al at 1173 K in a Tian–Calvet calorimeter. The experimental value is in good agreement with Density Functional Theory (DFT) calculations. Finally, all these new results are discussed regarding the abundant literature on the ZrCr2 Laves phases.

Crystallization experiments of the wheel-and-axle host compound, 1,4-phenylene-bis(di-p-tolylmethanol), from pyridine and methylpyridine mixtures

1,4-Phenylene-bis(di-p-tolylmethanol) (H), a host compound with the wheel-and-axle design, formed complexes with organic guest solvents pyridine (PYR) and 2-, 3- and 4-methylpyridine (2MP, 3MP and 4MP). The host: guest (H: G) ratios were 1:3, 1:2, 1:2 and 1:1, respectively. Host crystallization experiments from mixed guests demonstrated H to prefer both PYR and 4MP; however, it was established that these difficult-to-separate (by fractional distillations) guest mixtures cannot be purified/separated by means of H through supramolecular chemistry strategies owing to these selectivities for PYR and 4MP being less than optimal. Single crystal X-ray diffraction experiments showed that each guest compound was held in its complex by means of a classical hydrogen bond with H, and that one of the preferred guests, PYR, experienced a significantly shorter contact of this type than the other guests. Hirshfeld surface analyses demonstrated that PYR was also involved in a greater percentage of (guest)N···H(host) interactions compared with the other guest molecules. Thermal analyses, on the other hand, revealed that 4MP (also a favoured guest species) formed the most stable complex of the four in this investigation. These results with H were compared to those obtained when employing a closely related host compound from a previous report, 1,4-bis(diphenylhydroxymethyl)benzene: while both host species preferred the same guests (PYR and 4MP), the extent of the selectivity of that host compound compared with H in the present work was significantly more enhanced. Thus, minor modifications may deleteriously affect the selectivity behaviour of closely related host compounds.

Synthesis and characterisation of the new oxyanion doped “0201–1201” type layered oxide, Sr4.5Fe2(S/Cr)0.5O9±δ

This work reports on an oxyanion containing Sr–Fe–O perovskite-related layered oxide system related to the “0201–1201” type material Sr4.5Cr2.5O9. Using solid state synthesis, we successfully incorporate SO42− and CrO42− to give Sr4.5Fe2(S/Cr)0.5O9±δ, with X-ray and neutron diffraction used to analyse the structure of these materials. Neutron diffraction experiments combined with 57Fe Mössbauer spectroscopy and X-ray absorption spectroscopy show not only the successful oxyanion incorporation, but also that these systems have the ability to accommodate excess interstitial anions. The stabilisation of these new phases highlights the potential to synthesise new perovskite-related compounds using oxyanion doping.

Universal simulation of absorption effects for X-ray diffraction in reflection geometry.

Analytical calculations of absorption corrections for X-ray powder diffraction experiments on non-ideal samples with surface roughness, porosity or absorption contrasts from multiple phases require complex mathematical models to represent their material distribution. In a computational approach to this problem, a practicable ray-tracing algorithm is formulated which is capable of simulating angle-dependent absorption corrections in reflection geometry for any given rasterized sample model. Single or multiphase systems with arbitrary surface roughness, porosity and spatial distribution of the phases in any combination can be modeled on a voxel grid by assigning respective values to each voxel. The absorption corrections are calculated by tracing the attenuation of X-rays along their individual paths via a modified shear-warp algorithm. The algorithm is presented in detail and the results of simulated absorption corrections on samples with various surface modulations are discussed in the context of published experimental results.

Wave functions consistent with experimental x-ray diffraction data: A hircocervus becomes reality

Since the early days of quantum physics, the possibility of obtaining wave functions consistent with experimental x-ray diffraction data has been envisioned. The idea is firmly grounded in the postulates of quantum mechanics and finds full support in the Hohenberg and Kohn theorem and Levy–Lieb search formulation of density functional theory. Within this framework, a rich history of research has unfolded over the years, introducing various strategies to obtain plausible one-electron reduced density matrices or wave functions that are compatible with x-ray structure factors. Approximately twenty-five years ago, all of this culminated with the development of the x-ray restrained wave function (XRW) approach. This method aims to determine wave functions that minimize the electronic energy of the examined systems while maximizing the statistical agreement between experimental and calculated x-ray diffraction data. Presently, the XRW technique stands as a well-established strategy, manifesting in various forms, and addressing numerous problems and challenges across chemistry, physics, and materials science. Moreover, there remains large room for improvement and extensions in the coming years. This paper will comprehensively review the current state of the x-ray restrained wave function approach, discussing its underlying foundations, historical background, theoretical details and extensions, practical applications, and forthcoming perspectives.

Thermal stability and decomposition kinetics of polybenzoxazine and oligomeric polyhedral octaphenyl silsesquioxane nanocomposites

AbstractIn this study, the impact of octaphenyl polyhedral oligomeric silsesquioxane (POSS) on the thermal stability of polybenzoxazine resin at 1, 3, and 5 wt% POSS loading through dynamic thermogravimetric analysis (TGA) at heating rates of 10, 20, 30 and 40°C min−1 was investigated. Besides, the decomposition kinetics of polybenzoxazine resin (PBZ) and various nanocomposites were studied using Kissinger, Friedman, Flynn‐Wall‐Ozawa (FWO) and Coats‐Redfern (CR) models and also, the activation energies of samples were calculated. At first, benzoxazine monomer was synthesized and then nanocomposites were prepared via solution mixing method. The qualitative dispersion of nanoparticles in benzoxazine resin was examined through the utilization of scanning electron microscopy and x‐ray diffraction experiments. The results showed that the addition of nanoparticles improved the thermal stability of PBZ resin specially at 1 wt% POSS loading and at higher POSS content the thermal stability of the resin decreased. As determined by TGA, the char yield of resin was enhanced by 2.6% upon the addition of 1 wt% nanoparticles. In addition, in 1 weight percent of nanoparticles, as the heating rate rose from 10 to 40°C min−1, the Integral Program Decomposition Temperature (IPDT) has increased by about 260°C, and this increase is about 183°C compared to the resin, and also elevating the heating rate, Td (5%) and Td (10%) weight loss of samples shifted to higher temperatures. The degradation mechanism of the resin and nanocomposites was evaluated through Kissinger, Friedman, FWO and CR models. The results displayed that the addition of 1 wt% nanoparticles increased the activation energy (Ea) values of the nanocomposites compared to that of neat resin and above this filler content, the Ea values decreased. The findings derived from the FWO model indicated that the inclusion of a 1 wt% filler raised the Ea values of the first and second stages of PBZ resin decomposition from 136–200 and 151–214 kJ mol−1 to 148–210 and 180–228 kJ mol−1, respectively.

Activation energy and crystal growth coefficient determination of t-ZrO2 using high-temperature synchrotron X-ray diffraction

Abstract Activation energy and crystal growth coefficient of t-ZrO2 (tetragonal zirconia) were determined through an in-situ synchrotron radiation X-ray diffraction (SR-XRD) experiment. The t-ZrO2 precursor was synthesized through (a) purification of zircon sand from Kereng Pangi, Kalimantan to zircon powder, (b) alkali fusion, and (c) co-precipitation. High-temperature SR-XRD experiments were carried out with varying holding times of 1, 2, and 3 hours at 900, 950, and 1000 °C, respectively, where the formation and crystal growth of t-ZrO2 were observed. The diffraction patterns show that t-ZrO2 has formed at 900°C for 1 hour and it grows accordingly. The effect of the heating temperature and holding time on the crystal growth shows that the size of hot crystals increases with increasing temperature and holding time. It is found that the activation energy of t-ZrO2, in general, decreases with holding time, i.e. from 75.3 kJ/mol (3 h) to 57.3 (1h). Meanwhile, Beck’s crystal growth coefficient value is between 0.3 at 900 °C and 0.2 at 1000 °C.

Photoresponsive silver nanowire nanoplatform for real-time drug delivery in non-small cell lung cancer therapy

In this study, we first successfully synthesized three different sizes and shapes of Ag nanowires (Ag NWs) using a polyol synthesis method. The size and morphology of the Ag NWs were controlled by the types of inorganic control agents in the reaction system (NaCl for 1, CuCl2 for 2, and FeCl3 for 3). The synthesized Ag NWs were characterized using scanning electron microscopy (SEM) and powder X-ray diffraction (PXRD) experiments. Subsequently, due to the favorable width of 1, we utilized it as an effective photosensitizer to construct a novel drug-loaded nanomaterial platform, namely 1-PLC@DOX (PLC stands for poly(ε-caprolactone), and DOX stands for Doxorubicin), to achieve on-demand drug release triggered by near-infrared (NIR) laser. The results indicate that the drug delivery system can achieve minimally invasive treatment of complex geometric defects. Under near-infrared irradiation, 1-PLC@DOX can heat up to 53.6 °C within 15 min, showing a unique heating platform on the heating curve, with ideal photothermal stability and heating effect compared to other groups. By toggling near-infrared irradiation on or off, 1-PLC@DOX can exhibit a stair-step drug release curve, suggesting that on-demand control of drug release using near-infrared laser as a trigger is feasible. In vitro biological evaluations demonstrate that 1-PLC@DOX exhibits good biocompatibility and anti-tumor ability, significantly reducing the invasive ability of A549 cells on non-small cell lung cancer (NSCLC) cells, and at the same time inhibiting the proliferation of cancer cells by regulating the p53 signaling pathway to cause apoptosis.

Influence of Ni on the Organization and Properties of AlCoCrFeMn High-Entropy Alloys by Laser-Sintering Technique

In order to investigate the effect of the Ni element on the properties of AlCoCrFeMn HEAs, this experiment prepared AlCoCrFeMn and AlCoCrFeNiMn HEAs by using a laser-ignition self-propagation sintering technique with an equal molar ratio. And analyzed the effect of the Ni element on the microstructure of AlCoCrFeMn HEAs by using a metallurgical optical microscope (OM), scanning electron microscope (SEM), energy spectroscopic analysis (EDS), X-ray diffraction (XRD), and other experiments. Characterization equipment was used to analyze the effect of the Ni element on the microstructure, physical phase structure, wear resistance, compressive properties, and corrosion resistance of AlCoCrFeMn HEA materials. The results show that after the addition of the Ni element, the AlCoCrFeNiMn HEA changes from a single BCC phase to one consisting of BCC and a small amount of an FCC phase, with an equiaxial organization, and the yield strength reaches 780 MPa and the compressive strength is 3920 MPa. The corrosion rate is 2.08 × 10−3 mm/a, and the corrosion resistance and mechanical properties are greatly increased.

Anti-inflammatory germacrane-type sesquiterpene lactones from Vernonia sylvatica

Nine new germacranolides, sylvaticalides A−H (1–9), and three known analogues (10–12) were isolated from the aerial part of Vernonia sylvatica. Their structures were established using comprehensive spectroscopic analysis, including high-resolution electrospray ionization mass spectroscopy (HR-ESI-MS) and 1D and 2D nuclear magnetic resonance (NMR) spectra. Their absolute configurations were determined by X-ray diffraction experiments. The anti-inflammatory activities of all isolated compounds were assessed by evaluating their inhibitory effects on the nuclear factor kappa B (NF-κB) pathway, which was activated by lipopolysaccharide (LPS)-stimulated human THP1-Dual cells, and the interferon-stimulated gene (ISG) pathway, activated by STING agonist MSA-2 in the same cell model. Compounds 1, 2 and 6 showed inhibitory effects on the NF-κB and ISG signaling pathways, with IC50 values ranging from 4.12 to 10.57 μmol·L−1.

Mo-doped La0.4Sr0.6FeO3-δ hollow fiber membrane for air separation and methane conversion

Ceramic oxygen transport hollow fiber La0.4Sr0.6Fe0.95Mo0.05O3-δ (LSFM5) membranes were fabricated via combined phase inversion and sintering technique. High-temperature X-ray diffraction experiments indicated that LSFM5 oxide undergoes second order phase transition at temperature above 300 °C from rhombohedral to cubic structure. The inner and outer surfaces of LSFM5 membranes were modified by acid etching and by depositing a surface decoration layer. For both kinds of membranes with modified surfaces, the enhancement of oxygen fluxes was observed at operating temperature range 860–980 °C, which indicates that the surface oxygen exchange reactions play a decisive role in the control of the oxygen transport. Catalytic experiments of methane partial oxidation (POM) by Ni/LSFM5 based oxygen-permeable membrane reactor exhibited good performance both in the mode with synthetic air on the supply side, and in the mode of POM coupled with CO2 splitting on the supply side.

Intrinsic mechanisms of shale hydration-induced structural changes

The interaction between a water-based working fluid and shale causes a change in shale structure, resulting in wellbore instability and greatly increasing drilling costs. On the basis of the black rock samples of the Longmaxi Formation, the structural change characteristics and internal mechanisms of shale hydration are investigated using scanning electron microscopy, fixed-point observation experiments, X-ray diffraction experiments, ion analysis, and energy spectroscopy analysis. In this study, the changes in the microscopic elements during the propagation of macroscopic cracks to hydration were studied and the ion exchange of brine and mineral hydration was analyzed. The results indicate that the interaction between water and shale leads to shale fracture along the bedding plane, the expansion of primary fractures, the generation of new fractures, and the occurrence of a high number of dissolution phenomena. The ion exchange cation precipitation of shale and the fluid is dominated by Ca2+, and the anion precipitated is mainly SO42−. Through the energy spectrum analysis of the whole-rock mineral composition changes and shale structural changes, it is believed that shale dissolution is mainly from carbonatite minerals, such as calcite. While the oxidation of pyrite in the aqueous environment provides a large amount of SO42− and H+ and fracture propagation mainly occurs in areas where non quartz inorganic minerals are distributed on the bedding plane. The intrinsic mechanism of shale hydration structural changes is revealed through the structural changes, mineral composition changes, and chemical reactions present during the water–shale interaction, which is significant for ensuring the wellbore stability of drilling.