Microscopic Physical Properties Research Articles

Study on improvement of impermeability of strongly weathered phyllite by microorganisms

The technology of strengthening weakness rock based on microbial mineralization has been widely concerned by researchers and engineers in recent years. The uniaxial compressive strength, permeability and microscopic physical properties of strongly weathered phyllite treated by microorganisms were investigated in this study. The microstructure study were conducted using nuclear magnetic resonance (NMR), scanning electron microscope (SEM) and X-ray diffraction (XRD). The results show that effective cementation is generated in weathered phyllite due to the microbial induced carbonate precipitation in the process of microbial modified weathering of phyllite, which can increase the strength up to 39 % of treated phyllite. The NMR results proved that the stone content can significantly affects the pore distribution of improved phyllite samples. The porosity is significantly reduced after adding microorganisms for improvement, the permeability changes from 0.019 to 0.022 md with different treatments in this study. A high stone content can promote the adhesion of microorganisms, which is conducive to the formation of calcium carbonate. Both excessively high or low levels of calcium chloride and urea can significantly affect on microbial and enzyme activities. The XRD results confirm the calcite which generated by the microbe-induced carbonate precipitation. Although the calcite content is low but with a wide distribution range, which can effectively decrease the porosity and permeability. That is to say, the wide distribution of calcite can improve the strength of weathered phyllite.

In situ formation of solidified supramolecular solvent based dispersive liquid-liquid microextraction for the enrichment of phenylurea herbicides in water, fruit juice, and milk

A convenient, efficient, and green dispersive liquid-liquid microextraction based on the in situ formation of solidified supramolecular solvents combined with high performance liquid chromatography was developed for the determination of four phenylurea herbicides in liquid samples, including monuron, monolinuron, isoproturon, and chlortoluron. Herein, a novel supramolecular solvent was prepared by the in situ reaction of [P4448]Br and NH4PF6, which had the advantages of low melting point, high density, and good dispersibility. In addition, the microscopic morphology and physical properties of supramolecular solvent were characterized, and the extraction conditions were optimized. The results showed that the analytes had good linearity (R2 > 0.9998) within the linear range. The limits of detection and quantification for the four phenylurea herbicides were in the range of 0.13–0.19 μg L−1 and 0.45–0.65 μg L−1, respectively. The prepared supramolecular solvent is suitable for the efficient extraction of phenylurea herbicides in water, fruit juice, and milk.

Viscoelastic Response in Hydrous Polymers: The Role of Hydrogen Bonds and Microstructure.

Water responsive polymers represent a remarkable group of soft materials, acting as a laboratory for diverse water responsive physical phenomena and cutting-edge biology-electronics interfaces. We report on peculiarly distinctive viscoelastic behaviors of the biobased water responsive polymer cellulose 10-undecenoyl ester, while biobased regenerated cellulose displays stronger hydroplastic behaviors. We discovered a novel hydrous deformation mechanism involving the stretching of hydrogen bonds mediated by hydroxyl groups and water molecules, serving as a crucial factor in accommodating deformations. In parallel, the microstructure of cellulose 10-undecenoyl ester with unique coexisting nanoparticles and a continuous phase of entangled chains is mechanically resilient in the anhydrous state but enhances structural stiffness in the hydrous state. This variation arises from a different hydration level within the hydrous microstructure. Such a fundamental discovery offers valuable insights into the connection between the microscopic physical properties that can be influenced by water and the corresponding viscoelastic responses, extending its applicability to a wide range of hygroscopic materials.

Automatic in situ short-distance deposition of PLGA/PLLA composite nanofibrous membranes for personalized wound dressings.

Improving the mechanical properties of wound dressings and achieving personalized automatic real-time in situ deposition are important for accelerating wound management and repair. In this study, we report a self-designed automatic in situ deposition device based on solution blow spinning (SBS) to prepare poly(lactic-co-glycolic acid) (PLGA) and poly-L-lactic acid (PLLA) composite (PLGA/PLLA) nanofibrous membranes for wound dressing at a short distance. Polymer solution and in situ deposition conditions, including air pressure, spinning distance, solvent extrusion rate, and spinning rate, were optimized using orthogonal experiments and characterized via dynamic mechanical analysis. The microscopic morphology and physical properties of the prepared PLGA/PLLA composite nanofibrous membranes show that their strength, adhesion, water vapor transmission rate (WVTR), water retention, water absorption, degradation, and other properties were sufficient for wound-dressing applications. To investigate the possibility of a biomedical wound-dressing material, tannic acid (TA) was incorporated into the PLGA/PLLA composite nanofibrous membranes. The resultant PLGA/PLLA/TA composite nanofibrous membranes exhibited good biocompatibility and exceptional antibacterial properties against both Escherichia coli and Staphylococcus aureus. A pilot animal study illustrated the potential of this in situ deposition of PLGA/PLLA/TA composite nanofibrous membranes across multiple applications in wound healing/repair by reducing wound scar tissue formation and fibroblast overactivation.

What’s the matter with condensed matter?

From the macroscopic to the microscopic physical properties of the world around us, condensed-matter and materials-science research have a huge impact on daily life. And yet, as James Kakalios highlights, the field remains on the periphery of popular-physics outreach – especially compared to astronomy and big science.

Microscopic Formation Mechanism and Physical Properties of Mo/Cu Composites with High Densification

The formation mechanism and physical properties of high-densification Mo/Cu composites are studied by analyzing materials' microstructure, atom diffusion near the phase interface and physical properties. In the liquid phase sintering, the atomic diffusion occurs at the interface of molybdenum and copper, mainly the diffusion of copper atoms into molybdenum phase. Copper atoms in the material diffuse into the molybdenum phase to form a micron sized Cu-Mo solid solution, and no compound phase is found in the material structure, which forms a good interface bonding effect and makes it have high densification. The average linear expansion coefficients, thermal conductivities, electrical conductivities and tensile strengths of high-densification Mo/Cu composites with different copper content are linearly correlated with copper content. Mo80Cu20 is organized as a connected molybdenum skeleton and a small amount of copper phase in the voids. The tensile fracture of Mo80Cu20 is mainly exhibited as brittle fracture of the sintering neck of the molybdenum phase. The copper phase in Mo70Cu30, Mo60Cu40 or Mo50Cu50 is in a connected state, with plasticity significantly increased. Under the action of tensile stress, the ductile fracture of copper phase and the brittle fracture of sintering neck of the molybdenum phase occur simultaneously in these materials.

Enhancement of the redox reactions of the La0.8Sr0.2MnO3 catalyst by surface acid etching: A simple synthesis strategy to high-performance catalysts for methane combustion

Methane emission and treatment is an extremely important environmental problem, and the key and core treatment method are the application and development of catalysts in the after-treatment system. In this study, a new non-noble metal catalyst, which named OALSM, was fabricated by etching La0.8Sr0.2MnO3 with oxalic acid for the removal of methane. Related experiments and theoretical explorations by scholars had shown that acid etching of perovskite surfaces could achieve effective optimization of the catalytic oxidation properties and microscopic physical and chemical properties of the materials. And the oxalic acid reacted with high-valence state Mn to generate abundant coordination unsaturated Mn3+ sites, which could produce more active oxygen species. In addition, OALSM showed a higher methane catalysis capability than the samples that were not subjected to acid etching. Among all the as-prepared catalysts, OALSM-0.01 M demonstrated the optimal methane catalytic activity with the T50 value of 336 °C, the T90 value of 417 °C, the activation energy of 47.02 kJ·mol−1, and the favorable structural stability and toxicity resistance. This integration strategy can rationalize an innovative protocol to into the design of composite catalysts for methane oxidation, to broaden the application of acid etching in VOC oxidation.

Establishment and Application of a Novel Four-Dimensional Model for Simulation of a Natural Water Flooding Reservoir—A Case Study of Nanpu No. 2 Structure in the BHW Basin

Long-term development of fluvial reservoirs causes regular changes in the microscopic pore-throat structure, physical properties and phase permeability curves of the reservoirs, and the evolution history of different oil layer varies. These effects can be explored using a four-dimensional (4D) model of the maturing field. The logging curves of 89 sand bodies of the Nanpu No. 2 structure in the Bohai Bay Basin were restored to the non-water flooded state based on the changing status of water flooding layers at different stages and levels, and an original geological model was established by combining data for the old wells. The time-varying relationship was incorporated in the dynamic model with surface flux as the variable, and the numerical simulation analysis was conducted based on the reservoir time-varying characteristics. The results showed that ① the logging data of the water-flooded layer significantly affected the simulation results of the geological model and can only be used for the establishment of the initial geological model after repositioning of time and space; ② the time variation of reservoir properties and relative permeability markedly affected the simulation results of the remaining oil. Reservoir parameters and fluid properties simulated by the 4D model were consistent with the data of water flooded layers in new wells during different periods; ③ the novel method significantly improved the fitting rate of the dynamic model, and the model was used to quantitatively describe the morphology of dominant seepage channels and reservoir variation parameters. The novel idea of ‘retreat as progress’ and ‘bring in to solve’ achieved the solution of the dynamic and static parameters of the 4D model according to each time step of space-time evolution. The results provide a guide for comprehensive adjustment and evaluation of Nanpu Oilfield for 52 well-times with an oil increase of 1.68 × 104 tons for the different stages.

Laboratory experiments based on tip probe － Scanning probe detection and regulation of ferroelectric domains and their microscopic physical properties

<sec>Ferroelectric and multiferroic materials have gained significant attention due to their potential applications in investigating emergent cross-coupling phenomena among spin, charge, orbit, and lattice in correlated electron systems, as well as promising candidates for prospective applications in advanced industries, <i>e.g.</i> data memory/processing, sensors, actuators, and energy-relevant devices. The structure and dynamic characteristics of ferroelectric domains can significantly affect the physical properties and device functions of materials, such as electrical conductivity, photovoltaics, and magnetoelectric coupling, particularly, novel topological domains can bring many new physical properties. These make it possible to design materials and devices through domain engineering methods. Therefore, exploring the microdomain structures and related physical property is expected to bring new material and device solutions for post-Moore's era information technology.</sec><sec>Accurate understanding of domain structures and their corresponding functionalities pose challenges to characterization techniques. In particular, it remains challenging to investigate the dynamics and cross-coupling behaviors on a nanoscale <i>in situ</i>. Nowadays, it is worthwhile to pay more attention to the multifunctional scanning probe microscopy technique, as it serves as a versatile and powerful nanoscale probe capable of exploring multifunctionalities. Multi-field stimulation such as electric field, magnetic field, light illumination, strain field, and thermal field can be combined with the advanced scanning probe microscopy technique, making it an ideal platform for in-situ manipulation of domain structure and its related functional response on a nano-scale.</sec><sec>In this study, we give a brief overview on the recent advances in our research group in detection and manipulation of ferroelectric domains and microscopic physical properties through multifunctional scanning probe microscopy technique. Special attention is paid to those topological domain structures such as vortex, center domain state and bubble domain in size-confined systems (ultrathin films/multilayers and nanodots/nanoislands) and their associated novel physical phenomena. In addition, the controllability of electric field driven magnetic switching in multiferroic heterostructures is also studied through size effect, interfacial coupling and domain engineering. Finally, we present some suggestions for future directions. Most of these studies are conducted by using the tip probe, so it is named the “Laboratory experiments based on tip probe”.</sec>

Intense and Superflat White Laser with 700-nm 3-dB Bandwidth and 1-mJ Pulse Energy Enabling Single-Shot Subpicosecond Pulse Laser Spectroscopy.

An optical spectrometer is a basic spectral instrument that probes microscopic physical and chemical properties of macroscopic objects but generally suffers from difficulty in broadband time-resolved measurement. In this work, we report the creation of ultrabroadband white-light laser with a 3-dB bandwidth covering 385 to 1,080 nm, pulse energy of 1.07 mJ, and pulse duration of several hundred femtoseconds by passing 3-mJ pulse energy, 50-fs pulse duration Ti:Sapphire pulse laser through a cascaded fused silica plate and chirped periodically poled lithium niobate crystal. We utilize this unprecedented superflat, ultrabroadband, and intense femtosecond laser light source to build a single-shot (i.e., single-pulse) subpicosecond pulse laser ultraviolet-visible-near-infrared spectrometer and successfully measure various atomic and molecular absorption spectra. The single-shot ultrafast spectrometer may open up a frontier to monitor simultaneously the ultrafast dynamics of multiple physical and chemical processes in various microscopic systems.

Laboratory evaluation on performance of emulsified asphalt modified by reclaimed ion exchange resin

The cold recycling technology using emulsified asphalt (EA) as the binder reduces the high pollution and high energy consumption of hot mix asphalt (HMA) pavement. However, the poor bonding ability and high temperature deformation resistance of EA limit its application. To improve the performance of EA and reduce the pollution of waste ion resin to the environment, this study used reclaimed ion exchanged resin (RIER) to modify EA and analyzed its performance through laboratory tests. Firstly, the ionic characteristics and basic properties of reclaimed ionic resin-modified emulsified asphalt (RIEA) were tested. In addition, the rheological properties of evaporation residues of reclaimed ionic resin-modified emulsified asphalt (RIEA) were tested by Dynamic Shear Rheometer (DSR). The interaction effect of RIER and evaporation residue of EA were analyzed by PalierneC model. After that, the adhesive properties and tensile properties of RIEA mixtures were characterized by boiling test and splitting test. Finally, the microscopic physical and chemical properties of RIEA evaporation residue were tested by Scanning Electron Microscope (SEM) and Fourier Transform Infrared Spectrometer (FTIR). The results showed that RIER improved the stability of RIEA. The conductivity of EA increased by 294 % and the Zeta potential increased by 36 % when the RIER content was 30 %. Meanwhile, the penetration degree and ductility of RIEA evaporation residue were decreased, the softening point of that were increased. The Brookfield viscosity of EA with 30 % RIER content increased by 181 %, the dynamic viscosity increased, and the adhesion performance was improved. In addition, the complex shear modulus (G*) and rutting coefficient (G*/sinδ) of RIEA evaporation residue increased, while its phase angle (δ)decreased. The PalierneC interaction model exhibited that the interaction of EA and RIER showed different temperature responses with the change of loading frequency. The indirect tensile strength (ITS) of RIEA mixture was improved by adding RIER, and its value reaches the maximum value when the amount of RIER added is 30 %. RIER and EA are tightly bound in microstructure, and they interweave to form a glue-linked structure. FTIR results show that, the RIEA evaporation residue exhibited new absorption peaks at 1793.4 cm−1, 1302.1 cm−1, 876.0 cm−1, 806.1 cm−1 wavenumbers indicating a chemical reaction between them.

High-Voltage FDS of Thermally Aged XLPE Cable and Its Correlation with Physicochemical Properties.

This paper aims to investigate the influence of thermal aging on a crosslinked polyethylene (XLPE) cable, and the relationships between the macroscopical high-voltage dielectric and the microscopical physicochemical properties are also elucidated. To better simulate thermal aging under working condition, the medium-voltage-level cable is subjected to accelerated inner thermal aging for different aging times. Then, high-voltage frequency domain spectroscopy (FDS) (cable sample) and analyses of microscopic physical and chemical properties (sampling from the cable), including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and elongation at the break (EAB), are conducted at different cable aging stages. The dielectric test results show that after a certain aging time, the high-voltage FDS curves of the cable have layered characteristics, and this phenomenon is more obvious as the aging degree increases. Moreover, the slope and the integral of the high-voltage FDS curves rise with aging time. The mechanism is deduced by the physicochemical results that thermo-oxidative aging results in increasing polar groups and dislocation defects in the crystal region, which leads to the above phenomenon. On the one hand, the appearance of polar groups increases the density of the dipole. On the other hand, the destruction of the crystal region increases the probability and amplitude of dipole reversal. In addition, the breaking of molecular bonds and the increase in the amorphous phase also reduce the rigidity of the XLPE molecular main chain. The above factors lead to obvious delamination and larger dielectric parameters of the thermally aged cable. Finally, according to the experimental results, an on-site diagnosis method of cable insulation thermal aging based on high-voltage FDS is discussed.

Molecular Simulation of Cement-Based Materials and Their Properties

Hydrated cement is one of the complex composite systems due to the presence of multi-scale phases with varying morphologies. Calcium silicate hydrate, which is the principal binder phase in the hydrated cement, is responsible for the stiffness, strength, and durability of Portland cement concrete. To understand the mechanical and durability behavior of concrete, it is important to investigate the interactions of hydrated cement phases with other materials at the nanoscale. In this regard, the molecular simulation of cement-based materials is an effective approach to study the properties and interactions of the cement system at the fundamental scale. Recently, many studies have been published regarding atomistic simulations to investigate the cement phases to define/explain the microscopic physical and chemical properties, thereby improving the macroscopic performance of hardened binders. The research in molecular simulation of cementitious systems involves researchers with multidisciplinary backgrounds, mainly in two areas: ① cement chemistry, where the hydration reactions govern most of the chemical and physical properties at the atomic scale; and ② computational materials science and engineering, where the bottom-up approach is required. The latter approach is still in its infancy, and as such, a study of the prevailing knowledge is useful, namely through an exhaustive literature review. This state-of-the-art report provides a comprehensive survey on studies that were conducted in this area and cites the important findings.

Synthesis and properties of fluorinated terphenyl liquid crystals utilizing 5,6-dihydro-4H-cyclopenta[b]thiophene as core unit

5,6-dihydro-4H-cyclopenta[b]thiophene was incorporated to fluorinated terphenyl and six novel liquid crystals were designed and synthesized by Suzuki coupling reactions in high yields. These mesogens possessed wide smectic A or nematic phase ranges, which proved the usefulness of this core in the formation of liquid crystal phase as 1,4-disubstituted phenylene-based reference compound have no mesomorphic phase. Besides, the birefringence and dielectric anisotropy values of liquid crystals were also increased, making this core a practical candidate for the modification of terphenyl-typed mesogens. The density functional theory calculations were then used and whose reliability was ensured by comparison of the experimental and calculated absorption spectrum. The calculated length/width ratios of mesogens were improved after the introduction of this core unit, which might promote the formation of mesomorphic phases. The orders of calculated polarizability and dipole moment of two representative mesogens and their references were in agreement with the sequences of their birefringence and dielectric anisotropy values, respectively, providing some relationship information between microscopic molecular structures and macroscopic physical properties.

Analysis of quantitative and qualitative extractive components extracted from hornbeam (Carpinus betulus L.) and yakal (Shorea astylosa Foxw.) wood

The aim of the study was analysis of quantitative and qualitative extractive components extracted from hornbeam (Carpinus betulus L.) and yakal (Shorea astylosa Foxw.) wood. Two wood species similar to each other in terms of microscopic structure and physical properties, the native wood of Hornbeam (Carpinus betulus L.) and the yakal wood (Shorea astylosa Foxw.) endemic to the Philippines, which is still little understood, were investigated. Wood is a material composed mainly of polymers called lignocellulose which includes: (cellulose, lignin and hemicelluloses), but also contains many extractive and mineral substances. . The extractive content of wood in temperate climates is approximately for up to 5% by weight of wood. Their identification is difficult because of the wide variety and multiplicity of compounds present. However, extractive compounds are important for the resistance of trees and wood to biological agents such as fungal infestation or insect infestation. Usually the zones of dead wood (heartwood or cored wood) are characterized by a higher content of extractives. The understanding of the chemical composition of extractives in wood can contribute to the development of wood preservative products and environmentally friendly and would be part of the green chemistry policy.

Optimizing electrode structure of carbon nanotube gas sensors for sensitivity improvement based on electric field enhancement effect of fractal geometry

With the rapid development of carbon nanotubes gas sensor, the sensitivity of the sensing response is becoming more and more demanding. Different from the traditional studies on gas-sensitive materials, this paper combines the microscopic dimensional effects and physical properties of fractal geometry theory from the structure and morphology of sensor devices. The electrode structures of carbon nanotubes gas sensor is designed and optimized by Hilbert–Piano curve. Simulation experiments demonstrate that the electric field intensity and hot spot distribution of the fractal electrode are superior to those of the traditional interdigital electrode. Moreover, a novel chemiresistive gas sensor is fabricated combining the characteristics of carbon nanotubes and fractal geometry, and a test with exposure to nitric oxide showed that the sensors with fractal electrode structures improved the gas sensing sensitivity over sensors with traditional geometrical structures. It provides a new idea for the exploration of gas sensing technology.

Influence of chemical treatment and drying method on the properties of cellulose fibers of luffa sponge

The exploration of modified luffa sponge (LS) cellulose fiber in the field of polymer composite can contribute to the development of high-performance and lightweight composites. In this study, two chemical treatments (10%NaOH–20%CH3COOH (Method 1) and 10%NaOH–5%Na2SO3 (Method 2)) and two drying methods (air drying and freeze-drying) were used to treat LS. The microscopic characteristics and physical properties showed that Methods 1 and 2 caused shrinkage of the LS fibers and increased their fiber density by 30.6% and 15.0%. Meanwhile, freeze-drying kept the cells of modified LS fibers full and decreased their fiber density by 5.0% and 21.0%, respectively. The tensile properties test analyses indicated that freeze-drying further increased the elongation at break values of modified LS fibers by 25.3% and 17.7%, respectively. The moisture absorption analyses showed that freeze-drying could further decrease the moisture absorption ratios of modified LS fibers by 25.8% and 35.8%, respectively, which was useful for improving the dimensional stability of composite materials. Moreover, the thermogravimetric analysis reveals that freeze-drying increased onset degradation temperatures of the modified fibers by 24.0 °C and 6.7 °C, which was beneficial to improve the thermal stability of the composite material.

Introduction of 5,6-dihydro-4H-cyclopenta[b]thiophene core unit into phenyl-tolane: Expanding the mesophase range and increasing the birefringence and dielectric anisotropy of liquid crystal

ABSTRACT Six novel phenyl-tolane type liquid crystals based on 5,6-dihydro-4 H-cyclopenta[b]thiophene core were designed and synthesised by Sonogashira coupling reactions in high yields. Two reference compounds were then used to clarify the effects of this new core on the mesomorphic behaviours and physical properties of phenyl-tolane type mesogens and found that these new core-based mesogens possessed wider mesophase ranges. Both the birefringence (Δn) and dielectric anisotropy (Δε) values were increased after the employment of this new core, offering an alternative option for the design and synthesis of high-performance phenyl-tolanes. The geometry, ultraviolet absorption, polarisability (α) and dipole moment (μ) of two representative compounds and their references were calculated by density functional theory to correlate the structure–property relationship of the new mesogens. The calculated energy minimum structures of the new mesogens showed well linearity and the molecular length/width ratio was increased, which would benefit the formation of the nematic phase. The orders of the calculated polarisability (α) and dipole moment (μ) of two representative compounds and their references were in accordance with the sequences of the measured birefringence (Δn) and dielectric anisotropy (Δε) values, respectively, which might shed light on the correlation between microscopic molecular structure and macroscopic physical properties.

Concentration and Velocity Profiles in a Polymeric Lithium-Ion Battery Electrolyte

Predictive and quantitative understanding of ion and mass transport in liquid and polymeric electrolytes is at the heart of electrochemistry. Here, the goal is to accurately simulate the performance of an electrochemical cell, for which the temperature- and concentration-dependent transport coefficients of a given electrolyte, as well as the thermodynamic mean salt molal activity coefficient, must be known. These are the conductivity, σ, the salt diffusion coefficient, D, and the cation transference number, t+. The transport coefficients must hence be extracted with high accuracy from experimental measurements. The transference number is defined as the ratio of current carried by the cation to the total electric current. Its importance with regards to energy density and power density was recognized in the early 1990s by Doyle, Fuller and Newman (1). Nevertheless, researchers still argue about transference number values, even in baseline systems such as lithium bistrifluoromethanesulfonimidate (LiTFSI) in Poly(ethylene oxide) (PEO) (2). The transference number can be measured via the steady-state Bruce-Vincent polarization method (3, 4), the Balsara-Newman method (5), as well as pulsed field gradients NMR (pfg-NMR) (6) and pulsed field gradients electrophoretic NMR (e-NMR) (2). Despite extensive efforts towards unified results of these approaches, in particular as a function of ion concentration, a clear picture has not yet emerged.Towards this end, we developed an alternative approach towards determining the ion transport properties. Specifically, we directly and operando measured precise microscopic and macroscopic physical properties of the electrolyte upon cell polarization in a Li/electrolyte/Li cell, combined this with calculations via concentrated solution theory continuum modelling (CM), and rationalized our findings with microscopic insight from molecular dynamics (MD) simulations. We utilized a well-studied benchmark model system electrolyte consisting of PEO and LiTFSI at Li+ to EO molar ratio of r = 0.1. Under constant voltage polarization, we directly measured the velocity associated with electrolyte and ions via heterodyne synchrotron X-ray photon correlation spectroscopy (XPCS), and the TFSI- concentration gradient from electrode to electrode via X-ray absorption microscopy (XAM). The significance of our results lies in the unification of microscopic and macroscopic predictions from simulation with experimental measurements as well as the self-consistent determination of a concentration-independent transference numbers of approximately 0.2. Our study paves the way for further length- and time-scale bridging understanding of ion transport.1. M. Doyle, T. F. Fuller, J. Newman, The Importance of the Lithium Ion Transference Number in Lithium Polymer Cells. Electrochimica Acta 39, 2073-2081 (1994).2. M. P. Rosenwinkel, M. Schönhoff, Lithium Transference Numbers in PEO/LiTFSA Electrolytes Determined by Electrophoretic NMR. Journal of The Electrochemical Society 166, A1977-A1983 (2019).3. J. Evans, C. A. Vincent, P. G. Bruce, Electrochemical Measurement of Transference Numbers in Polymer Electrolytes. Polymer 28, 2324-2328 (1987).4. P. G. BRUCE, C. A. VINCENT, STEADY STATE CURRENT FLOW IN SOLID BINARY ELECTROLYTE CELLS. J. Electroanal. Chem. 225, 1-17 (1987).5. D. M. Pesko, S. Sawhney, J. Newman, N. P. Balsara, Comparing Two Electrochemical Approaches for Measuring Transference Numbers in Concentrated Electrolytes. Journal of The Electrochemical Society 165, A3014-A3021 (2018).6. D. M. Pesko et al., Negative transference numbers in poly(ethylene oxide)-based electrolytes. Journal of the Electrochemical Society 164, E3569-E3575 (2017).

Microscopic mechanism of sandstone hydration in Yungang Grottoes, China

Abstract The macroscopic engineering properties of sandstone are dominated primarily by mineral features in a microscopic scale. This study will investigate the microscopic physical and mechanical properties of the main minerals (quartz, K-feldspar, Na-feldspar and kaolinite) in Yungang Grottoes sandstone, using the molecular mechanics and the molecular dynamics simulations. The microscopic physical properties were represented by density and volume. The microscopic mechanical properties were represented by Young’s modulus and Poisson’s ratio. The microscopic mechanical properties of the minerals in various directions were then explored. The influences of water molecules and the surrounding temperature on the microscopic physical and mechanical properties of the minerals were furthermore investigated. It is found that the differences in the microscopic densities between the simulated results and those from the open data set are, respectively, 0.37%, 1.15% and 9.16%, for the quartz, Na-feldspar and kaolinite cells; the microscopic mechanical properties of various minerals have a significant anisotropy; the Young’s modulus of halloysite decreases by 75.86% compared with that of kaolinite; as the water molecule number increased from 0 to 5, the Young’s moduli of K-feldspar, Na-feldspar and kaolinite cells decreases by 31.31%, 55.05% and 42.60%, respectively; for each mineral, as the temperature increases from 243.15 to 303.15 K under one atmospheric pressure, the volume increases and the density decreases. Those results may have a theoretical significance for the analysis of microscopic mechanism of hydration in the Yungang Grottoes sandstone.