Types Of Materials Research Articles

Acoustic Waves in Axial Crystals and Quasicrystals with Preliminary Finite Strains

The dynamic problem of acoustic wave propagation in elastic bodies with preliminary finite deformations is formulated. Several types of anisotropic elastic materials are considered: hexagonal crystals of class [Formula: see text], transversally isotropic materials and axial quasicrystals with an arbitrary order of the rotary axis. A variant of nonlinear hypoelasticity relations is constructed for these materials. In the constitutive relations, the tensor connecting the rate of change of the stress tensor and the strain rate tensor is a function of deformations. The propagation of acoustic waves in a hypoelastic material with preliminary finite deformations and stresses is described as a process of weak perturbations superimposed on finite strains. The characteristic features of elastic wave propagation in hexagonal crystals and axial quasicrystals are revealed. Within the framework of the constructed models, the most significant differences are found in the phase velocities of a transverse wave with a polarization vector located in the crystallographic plane (110). Unlike hexagonal crystals, in axial quasicrystals, there are such directions of acoustic wave propagation for which the phase velocities of transverse waves are insensitive to the degree of preliminary deformations. Based on the solution of the problem of elastic wave propagation, a program of dynamic experiments with macrosamples, which allows to distinguish axial quasicrystals from hexagonal crystals by the peculiarities of acoustic wave propagation, is proposed.

BIM-Based Automatic Extraction of Daily Concrete and Formwork Requirements for Site Work Planning

Material planning is important in construction, for it affects procurement, cost, and schedule. Proper planning of material supply and logistics helps streamline the performance of all tasks through the avoidance of excessive or insufficient material supply. Material planning relies on quantity takeoff (QTO) and project schedules. Conventionally, quantity takeoff was a manual process based on 2D drawings and human interpretation and was error-prone. Presently, with the popularity of Building Information Modelling (BIM), in BIM-based projects, using inbuilt quantity takeoff functions, quantities of work can be generated automatically from BIM models to aid the quantity takeoff. However, if those inbuilt QTO solutions are object-based, then the quantities of works extracted may not meet the requirements of the users in selected cases, e.g., in zone-based construction projects. Also, for estimating daily material requirements, the accuracy of the quantities of work becomes more important, not only for the purpose of efficient planning but also for reducing construction waste. Since works using the same type of material can go overlapping, in addition to estimating the amount of material for each work, the total amount of material for a day must also be calculated. Thus, this research aims to develop a framework for automatic extraction of zone-based concrete volumes and formwork positions for cast-in-place concrete structures using the data in BIM models, followed by linking them with project schedules for estimating daily concrete and formwork requirements. This framework extends the body of knowledge by introducing an innovative algorithm for automatically calculating overlapped areas between concrete members and a rule for naming tasks in the schedule, followed by evaluating the formwork requirements without drawing formwork in a 3D model. A software tool will be developed to achieve the aim, and a case study will be used to validate the proposed framework.

Performance and durability of additively and subtractively manufactured resin-based onlay restorations after thermomechanical aging.

To evaluate the effect of material type on dimensional stability, occlusal surface wear, fracture resistance, and failure behavior of resin-based onlay restorations. A mandibular right first molar typodont was prepared and digitized using an intraoral scanner to virtually design an onlay restoration with the minimum occlusal thickness of 1.5mm. Resin-based onlay restorations (n = 15 per group) were fabricated either additively from 2 different resins indicated either for definitive or interim use or subtractively with a composite resin. After cementing onlays to corresponding dies, each of them was digitized before and after thermomechanical aging (B-STL and A-STL), and then subjected to load-to-failure test to evaluate fracture resistance. The B-STL and A-STL of each onlay were also compared to assess the dimensional stability and occlusal surface wear. One-way analysis of variance and Tukey honestly significant difference tests were used to evaluate dimensional stability, occlusal surface wear, and fracture resistance. The chi-square test was used to evaluate the Weibull modulus and characteristic strength among the groups (α = 0.05). Material type affected investigated outcomes (p<0.001). The additively manufactured resin indicated for definitive use led to the highest external surface deviations and the additively manufactured resin indicated for interim use led to the highest mesiodistal width deviations (p≤0.033). The onlays fabricated from the additively manufactured resin indicated for definitive use had the highest occlusal surface wear, while those in composite resin had the lowest (p≤0.006). The composite resin onlays had the highest fracture resistance values and reliability (p≤0.035). Tested subtractively manufactured composite resin had the lowest occlusal surface wear with the highest fracture resistance and reliability. Additively manufactured resins had lower dimensional stability, while tested resin for additively manufactured definitive restorations had the highest occlusal surface wear.

Covalent integration of polymers and porous organic frameworks

Covalent integration of polymers and porous organic frameworks (POFs), including metal-organic frameworks (MOFs), covalent organic frameworks (COFs) and hydrogen-bonded organic frameworks (HOFs), represent a promising strategy for overcoming the existing limitations of traditional porous materials. This integration allows for the combination of the advantages of polymers, i.e., flexibility, processability and chemical versatility etc., and the superiority of POFs, like the structural integrity, tunable porosity and the high surface area, creating a type of hybrid materials. These resulting polymer-POF hybrid materials exhibit enhanced mechanical strength, chemical stability and functional diversity, thus opening up new opportunities for applications across a large variety of fields, such as gas separation, catalysis, biomedical applications, environmental remediation and energy storage. In this review, an overview of synthetic routes and strategies on how to covalently integrate different polymers with various POFs is discussed, especially with a particular focus on methods like polymerization within, on and among POF structures. To investigate the unique properties and functions of these resultant hybrid materials, the characterization techniques, including nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and scanning electron microscopy (SEM), gas adsorption analysis (BET) and computational modeling and machine learning, are also presented. The ability of polymer-POFs to manipulate the pore environments at the molecular level affords these materials a wide range of applications, providing a versatile platform for future advancements in material science. Looking forward, to fully realize the potential of these hybrid materials, the authors highlight the scalability, green synthesis methods, and potential for stimuli-responsive polymer-POF materials as critical areas for future research.

Research on the Mechanical Properties of EPS Lightweight Soil Mixed with Fly Ash

Expanded polystyrene (EPS) bead–lightweight soil composites are a new type of artificial geotechnical material with low density and high strength. We applied EPS bead–lightweight soil in this project, replacing partial cement with fly ash to reduce construction costs. EPS beads were used as a lightweight material and cement and fly ash as curing agents in the raw soil were used to make EPS lightweight soil mixed with fly ash. The EPS bead proportions were 0.5%, 1%, 1.5%, and 2%; the total curing agent contents were 10%, 15%, 20%, and 25%; and the proportions of fly ash replacing cement were 0%, 15%, 30%, 45%, and 60%, respectively. Unconfined compressive strength (UCS) and scanning electron microscopy (SEM) tests were conducted. The results showed that the EPS content, total curing agent content, and proportion of fly ash replacing cement had a significant impact on the UCS of the lightweight soil. This decreased with an increase in EPS content and decrease in total curing agent content and decreased with increased proportions of fly ash replacing cement. When the proportion of fly ash replacing cement was not too high, the strength of the lightweight soil decreased less, and its performance still met engineering needs. At the same time, the soil can also consume fly ash and reduce environmental pollution. EPS lightweight soil mixed with fly ash still has advantages, and it is recommended to keep the proportion of fly ash replacing cement less than 30%. The failure patterns for lightweight soil mainly include splitting failure, oblique shear failure, and bulging failure, which are related to the material mix ratio.

Research Progress on P2/O3-Composite Layer Metal Oxide Cathode Materials for Sodium-Ion Batteries

Abstract The high cost and uneven distribution of lithium resources have prompted searches for alternatives to lithium-ion batteries. Among various alternatives, the sodium layered oxide cathode materials, have shown significant research potential due to their low cost. Layered oxide materials can be categorized into sodium-rich O3 types and sodium-deficient P2 types, which have different structural features. O3 type materials offer high specific capacities but suffer from complex pathways for Na+ de-intercalation, slow Na+ diffusion, and poor air stability. P2 type materials are limited in full cell applications due to their lower practical specific capacities. Therefore, researchers conceived the idea of combining the advantages of both to construct P2/O3 composite structure cathode materials (CSMs), utilizing the synergistic effects of the CSMs to overcome the limitations of single structure material, and successfully synthesized CSMs with appropriate specific capacities. These materials effectively suppress unfavorable phase transitions and enhance Na+ diffusion coefficient, thereby improving electrochemical performance. This paper reviews the recent advancements in CSMs for sodium-ion batteries, highlighting synthesis strategies that incorporate "cationic potential" theory, element substitution, sodium content adjustment, and control of calcination processes to synthesize diverse CSMs.

Trivalent Rare Earth Ion‐Doped Metal Halide Perovskite Near‐Infrared Semiconductors for High‐Performance Optoelectronic Devices

AbstractGiven the extensive application of near‐infrared (NIR) emission, the quest for efficient and versatile NIR semiconductors have attracted tremendous attention. Leveraging trivalent rare earth (RE3+) ions doping, the integration of metal halide perovskites with RE3+ ions makes it easy to achieve NIR‐II emission (1000–1700 nm). However, although showing promise in bioimaging, optical communication, and night vision, enhancing NIR‐II emission intensity to promote further progress in real‐world applications remains a challenge. This review summarizes the recent advancements in RE3+ ion‐doped perovskite NIR semiconductors, and discusses what kind of properties are needed and how to achieve desired optical properties in various applications. The review starts with the synthesis methods for various material types with rich examples. Following this, the mechanisms of strategies for optimizing NIR luminescence performance are discussed in detail. Furthermore, the review highlights their multifunctional applications both as an electrically driven emitter in NIR light‐emitting diodes (LEDs) and as a down‐conversion emitter in photovoltaic devices (PVs) or phosphor‐converted LEDs (pc‐LEDs). Finally, insights on how to fill the gap between current research and future goals are provided. This review aims to provide a deeper understanding of RE3+ ion‐doped NIR light‐emitting perovskite materials, and to promote the exploration of efficient NIR emitters.

Polarizability, plasmons and damping in pseudospin-1 gapped materials with a flat band

The subject of our present investigation is the collective electronic properties of various types of pseudospin-1 Dirac-cone materials with a flat band and finite bandgaps in their low-energy spectra. Specifically, we have calculated the dynamical polarization, plasmon dispersions, as well as their decay rates due to Landau damping and presented the closed-form analytical expressions for the wave function overlaps for both the gapped dice lattice and the Lieb lattice. The gapped dice lattice is a special case of the more generalα-T3model such that its band structure is symmetric and the flat band remains dispersionless. On the other hand, the Lieb lattice has a flat band which appears at the lowest point of its conduction band. Our results for these two materials exhibit unique features in the plasmon spectra and their damping regions, which have never been previously reported. For example, the particle-hole modes of a Lieb lattice appear as finite-size regions, while the plasmon modes exist only in areas with small wave numbers but an extended range of frequencies.

Technology and raw material analysis of Linear Pottery culture ceramics from the Eastern Carpathians, Romania

Only a few Neolithic settlements attributed to the Linear Pottery culture 5100-4850 cal. BC) are known from the Sub-Carpathian area of Eastern Romania. From the Neamţ Depression, settlements were known from Târpeşti and recently from Topoliţa. The aim of the presented analyses was to determine data regarding ceramic technology at the Topoliţa site and to compare it with LBK ceramic technology in neighbouring areas. It was found that ceramic production patterns at Topoliţa were similar to those at nearby LBK sites in Romania and even to pottery from southeastern Poland. However, the selection of raw materials varied. At Topoliţa, only one type of raw material was used, while the nearest site at Târpeşti employed several different raw materials. These differences underscore the importance of local environmental factors in understanding ceramic production practices. The technological similarities between Topoliţa and Poland suggest that knowledge and practices were transmitted through cultural interactions and long-distance exchange networks.

Non‐Original and Digitally Captured Handwriting: Considerations for Forensic Handwriting Examinations

ABSTRACTNon‐original handwriting and signatures are commonly encountered in the forensic environment. Non‐original handwriting could be the product of a reproduction, or originally executed writing that has been digitally recorded or captured. Forensic handwriting examiners (FHEs) are required to take into consideration several limiting factors when expressing opinions regarding apparent similarities and/or dissimilarities when examining non‐original samples of writing. Handwriting that has been digitally captured has a unique set of limitations but could also have additional, useful features such as dynamic measurements that, under certain conditions, can contribute to the comparison. This article is an overview of the rationale for the special treatment and thought afforded to non‐original and digitally captured writing during a handwriting or signature examination and comparison process and is intended to guide the thought process and considerations required by FHEs when encountering this type of material.

Recent advances in research from plastic materials to microplastics

Plastics have become ubiquitous in our lives. Due to the ever-increasing population, rapid urbanization, and industrial advancement, the use of plastics has increased manifold. These plastic materials often disintegrate into microplastics (MPs) which are less than 5mm in size. MPs mostly enter aquatic habitats through improper waste management, illegal dumping, and unavoidable and unintentional discharges that take place during construction, manufacturing, farming, domestic consumption, and recreational activities. This review centers on exploring the origin, occurrence, and possible adverse effects of MPs on human well-being. Of the 485 literature reviewed for the study between 2014- 2023, 105 were found to be related to the MPs which were spread over 10 themes. The maximum number of papers were on sources of MPs, followed by MPs in freshwater ecosystems and waste management. The least number of literature was from the themes, transport of MPs and MPs in the soil environment. The literature was published mostly in China, India, Europe, and the Americas. Other countries like Australia, Latin America, Africa, and the Middle East contribute very little. The literature scan reveals that only 9% of all the generated plastic waste material is recycled, 12% is burned, and 79% of plastic litter is dumped in landfills and oceans. The dumped plastic settles and pollutes a variety of environmental matrices. MPs are intentionally manufactured to be added to personal care products that are washed down the drains through sewage or industrial wastewater. These MPs vary in density and colour, subject to the polymer type, and are present in varying sizes and concentrations in aquatic environments. The characterization of MPs originating from different types of polymer materials, in the reviewed literature, was performed based on the data obtained from Scanning Electron Microscopy Energy Dispersive Spectroscopy (SEM-EDS), Attenuated Total Reflection Fourier Transform Infra-Red spectroscopy (ATR-FTIR), Raman spectroscopy, and Atomic Force Microscopy (AFM). MPs have the potential to absorb harmful hydrophobic pollutants from the surroundings resulting in an indirect transfer of contaminants into the food web. Such MPs enter and affect humans, causing problems with the reproductive system, body weight, sex ratio, and live births. MPs pose a serious threat to organisms when ingested since they can obstruct the digestive tract, leading to oxidative and pathological stress, slowing down growth, and interfering with reproduction. Apart from the above, a comprehensive analysis of MP pollution, as well as its effect on human beings and the environment, has been discussed in terms of source identification and abundance. Also, has been discussed is a detailed review of the existing waste material recycled into new materials or reused without alteration or degradation to produce new energy sources. In the end, integrated strategies have been proposed to prevent the input of plastic waste material into the environment, by source control, improved plastic waste management, and techniques for degradation and conversion of MPs.

Technology of manufacturing copper and bronze tools of the Petrovka Culture of the Southern Trans-Urals and Middle Tobol region

The article presents the results of metallographic analysis of the Petrovka Culture tools from the southern Trans-Urals and Middle Tobol River region of the 19th–18th centuries BC (47 items). A certain correlation has been determined between the functional purpose of an item, the type of raw material, and the tool manufacturing scheme. The tools were mainly made of copper contaminated with impurities, obtained from oxide-carbonate ores with the addition of chalcocite-covellite minerals. A butted axe, sickles, knives with handles, tanged chisels, hooks, and some awls were made of copper, both by casting in a mold with subsequent finishing and by forming forging. Copper tools obtained by casting often had casting defects — shrinkage cracks and warping of the metal. In most cases, the tools were finished either in the regime of incomplete hot forging at 300–500°C, or hot forging at 600–800°C and pre-melting temperatures of 900–1000°C. During the Petrovka period, tin and tin-arsenic bronze started being used for manufacturing adzes, chisels, handled knives, the majority of awls, needles, spear-heads, and arrows. More progressive types of alloys in terms of fluidity, filling mold without defects in the form of low-alloy tin and tin-arsenic bronzes (Sn up to 7%, As up to 4%) came from related tribes of the Petrovka Culture of Saryarka, possibly from the Petropavlovsk Ishim region. The resulting castings were of high quality with smooth surface without metal warping defects. Subsequent finishing was carried out by selecting optimal heat treatment regimes mainly at 600–800°C or 900–1000°C, as well as using incomplete hot forging at 300–500°C. The hardness of the tools finished by forging with heating significantly exceeded the microhardness of the processed copper by 1.5–2 times.

Characterization of PFAS Residuals: A Case Study on PFAS Content in a Firefighting Foam Delivery System of an Aircraft Rescue and Firefighting Vehicle.

When fire suppression systems that held aqueous film forming foams (AFFF) are transitioned to per- and polyfluoroalkyl substance (PFAS)-free firefighting formulations, PFAS can dissolve from the wetted surfaces of the systems and release into the new firefighting formulations. The overall objective of this work was to characterize PFAS residual mass on the wetted surfaces of aircraft rescue and firefighting (ARFF) vehicle on-board fire suppression system components from the water, mixed fire water, and foam concentrate systems with various geometries, materials of construction, and locations within the fire suppression system. The ARFF vehicle components were dismantled from the system after a triple water rinse procedure which removed 19,600 mg total measured PFAS post-TOP assay from the foam concentrate system and 23 mg total measured PFAS post-TOP assay from the water system. Results for total mass of PFAS on each part indicate most of the residuals were present on parts which have large surfaces areas or the rubber or brass parts. For large surface area plastic parts (i.e., foam and water tanks), the overall mass on these parts was greater than other parts even though the PFAS residual concentrations were lower compared to other material types due to larger surface areas for accumulation. Parts constructed of rubber or brass appeared to have higher measured PFAS surface residual concentrations as compared to parts constructed of plastic or stainless steel.

Is Saccocoelioides bacilliformis Szidat, 1973 (Digenea: Haploporidae) a valid species? Genetic and morphological studies of this controversial species.

Saccocoelioides is a genus within the family Haploporidae and is distributed throughout the Americas. The recent application of molecular techniques has facilitated the reorganization of this genus and the description of new species, resulting in a current total of 28 species. In Argentina, 11 species have been identified; however, the validity of Saccocoelioides bacilliformis and Saccocoelioides octavus remains controversial. Recently, specimens of digeneans were collected from two distinct geographical locations: the Paraná River basin (Misiones province) and the Río de la Plata basin (Buenos Aires province). These specimens were found parasitizing two different fish species: Bryconamericus sylvicola and Bryconamericus iheringi. Sequences of the 28S and COI genes were obtained for both digeneans from the two collection sites and hosts. The morphological study, combined with genetic sequences, confirmed their assignment to the genus Saccocoelioides. The COI and 28S gene sequences obtained from specimens at both collection sites exhibited genetic distances of 0.13% and 3.41%, respectively, indicating that these Saccocoelioides specimens represent a single species. The comprehensive taxonomic study of the newly collected specimens, along with an examination of the type material of S. bacilliformis and S. octavus, allows us to confirm the validity of both species. Argentina is home to more than 550 species of freshwater fauna, and it is likely that new species of Saccocoelioides remain to be discovered in underexplored regions of the basin, such as the Uruguay, Pilcomayo and Bermejo rivers.

Broadband nonlinear optical response of lead telluride quantum dots for all-solid-state pulse lasers from visible to mid-infrared

Lead telluride (PbTe), an emerging member of the group IV-VI monochalcogenides, exhibits superior properties such as higher density of states, obvious band anisotropy, and high carrier mobility. Moreover, the stronger nonlinear optical response of quantum dots (QDs) makes this type of low-dimensional material highly competitive for broadband pulse laser applications. In this work, high-quality PbTe QDs are fabricated using a liquid phase exfoliation (LPE) method. Utilizing PbTe QDs as what we believe to be a novel saturable absorber (SA), the broadband nonlinear optical responses spanning from visible to mid-infrared wavelengths are systematically investigated. Experimentally, broadband solid-state passively Q-switched lasers are successfully implemented based on PbTe QDs SA at 0.64, 1.06, 1.9, and 2.7 µm, respectively. Notably, this is believed to be the first time that PbTe QDs have been employed as SA in broadband solid-state pulse lasers. These findings indicate that PbTe QDs exhibit significant potential as saturable absorbing materials and can serve as effective optical modulators in broadband laser applications.

RECEIVING AND ADSORPTION CHARACTERISTICS OF BIOCARBON MATERIALS FROM HOUSEHOLD WASTE

The aim of this research is the development of new carbon materials based on agricultural waste and a detailed study of their physicochemical properties, which allows to evaluate the potential directions of use of these materials in industry and environmental technologies. Within the framework of the work, four types of waste were chosen, in particular, wood sawdust, apple cake, as well as wheat and corn husks, which are widely available and rarely used as raw materials for creating adsorbents. The selected materials were subjected to the process of pyrolysis at a temperature of 500°C for one hour, which effectively preserves the porous structure of the material and improves its adsorption properties. The obtained samples of biocarbon materials were analyzed using nitrogen porosimetry, which made it possible to determine their adsorption potential, porosity, and total surface area. The results of the study showed a significant difference in the adsorption capacity of the samples, depending on the type of raw material. The sample based on corn husk demonstrated the highest adsorption activity, which indicates its potential for water purification from various types of pollution, including organic and inorganic compounds, heavy metals and other toxic substances. In addition, an additional analysis of the samples was carried out in order to assess their potential in other industries. In particular, the revealed porosity and surface area of ​​the materials allow us to consider them as promising components for filtration systems, catalysts in chemical reactions, materials for energy storage, as well as means for environmental protection and environmental restoration. The results of the study confirm that the use of agricultural waste for the creation of functional carbon materials is not only economically beneficial, but also an ecologically appropriate approach, which contributes to reducing the amount of waste and creating new opportunities for sustainable development.

Revision of Iphione Kinberg, 1856 (Annelida, Aphroditiformia, Iphionidae)

The only revision of Iphione was made by Pettibone in 1986, who recognized four species including two newly described in that work: I. muricata (Savigny in Lamarck, 1818) (type species), I. ovata Kinberg, 1856, I. treadwelli Pettibone, 1986, and I. henshawi Pettibone, 1986. She included I. fimbriata de Quatrefages, 1866, I. glabra de Quatrefages, 1866, and I. fustis Hoagland, 1920 within I. muricata, and I. spinosa Kinberg, 1856 and I. hirotai Izuka, 1912 in I. ovata. Three other species were later added to the genus: I. reticulata Amoureux, Rullier &amp; Fishelson, 1978 from the Red Sea, I. coriolis Hanley &amp; Burke, 1991 from the Coral Sea, and I. malifera Piotrowski, 2014 from the Philippines. A recent contribution showed that I. ovata ranges from the Red Sea to the Eastern Pacific and includes I. spinosa and I. reticulata. Our objectives were to revise the genus, evaluating all species and describing new ones by assessing the relevance of morphological features, assisted in part with COI sequence data. We studied the morphology of type and non-type material from 18 institutions and sequenced 52 specimens representing 11 species. We found that the size and position of eyes, the size relationships between cephalic appendages, and the number of rows of macrotubercles in elytra vary with body size. The most relevant diagnostic features for species delineation, confirmed by genetic species delineation, are the type and size relationships of macrotubercles, the presence of fimbriae, the development of the basal tubercle of dorsal cirrophores, the type of neurochaetae (falcate versus acicular), and their tips (uni- vs bidentate; or simple vs hooded). We clarified the type species of the genus as I. ovata, and recognized 17 species, nine previously described and eight new. Our main results include: 1) the restriction of I. muricata; 2) the reinstatement of I. fimbriata including I. fustis; 3) redescriptions of I. coriolis, I. henshawi and I. treadwelli; and 4) the description of eight new species: I. ankeri sp. nov. from Guam, I. corbari sp. nov. from the Saya de Malha Bank, I. harrisae sp. nov. from French Polynesia, I. hourdezi sp. nov. from New Caledonia, I. hyndmani sp. nov. from Hong Kong, I. readi sp. nov. from the Red Sea (including many earlier records of I. muricata), I. richeri sp. nov. from New Caledonia, and I. wilsoni sp. nov. from Australia. Descriptions the eight newly described species include only one based upon a single specimen. Keys are included for the genera in the family, and species of Iphione.

A Family of Two-Dimensional Quaternary Compounds A2BXY2 (A = K, Na; B = Li, Na; X = Al, Ga, In; Y = P, As, Sb) for Optoelectronics Applications.

Expanding material types and developing two-dimensional (2D) semiconductor materials with high performance have been hotspots in the field. In this research, it is found that the 12 existing semiconductors A2BXY2 (A = K, Na; B = Li, Na; X = Al, Ga, In; Y = P, As, Sb) have a pronounced layered structure. We predict their 2D structures and properties, using first-principles calculations. Lower exfoliation energies confirm the feasibility of mechanical exfoliation from their bulk phases and that the 2D structures can be stabilized independently at room temperature. Interestingly, A2BXY2 has an anionic tetrahedral one-dimensional chain or two-dimensional mesh structure of [XY2]3- composed of elements III-V. All A2BXY2 monolayers exhibit direct or indirect band gap features (0.78-1.94 eV). More encouragingly, the A2BXY2 monolayers possess ultrahigh carrier mobilities (∼105 cm2 V-1 s-1) at room temperature. Furthermore, the results based on the nonequilibrium Green's function indicate that 2D A2BXY2 exhibits a high ON/OFF ratio (∼104). To sum up, the A2BXY2 family is an outstanding promising candidate for optoelectronics application.

Research on the Elastic Properties of Deep Rock Composites Under High Pressure

This paper presents a three-dimensional model of the definitive structure of gypsum, calcite and quartz crystals, which are the primary components of deep rock mass. The optimization of the primary components of deep rock mass material was performed under pressures ranging from 0 to 120 MPa using the first principles method. This led to the determination of the structural constants of the primary component crystals within the deep rock material. Furthermore, the variation rule of mechanical parameters, including elastic constants, for the primary components of deep-seated rock materials under different pressures was also investigated. The findings indicate a clear downward trend in the partial crystal structure parameters of deep-seated rock materials with increasing pressure. The primary components of each rock mass material display disparate compressibility properties in distinct directions when subjected to uniaxial compression. In conclusion, the anisotropic elastic properties of gypsum crystals, calcite crystals and quartz crystals under different pressures were investigated. The anisotropic cloud diagrams of bulk modulus, elastic modulus and shear modulus were presented for the three types of rock material at 0 MPa, 60 MPa and 120 MPa, respectively. In conclusion, we derived the theoretical equations for the elastic tensor matrix of composite materials using the principle of superposition. Furthermore, we studied and obtained the elastic tensor matrix for composite materials within the deep rock mass. These results provide essential theoretical guidance for the development of underground space and the analysis of deep rock dynamics.

In vitro culture of leukemic cells in collagen scaffolds and carboxymethyl cellulose-polyethylene glycol gel.

Chronic lymphocytic leukemia (CLL) is a common adult leukemia characterized by the accumulation of neoplastic mature B cells in blood, bone marrow, lymph nodes, and spleen. The disease biology remains unresolved in many aspects, including the processes underlying the disease progression and relapses. However, studying CLL in vitro poses a considerable challenge due to its complexity and dependency on the microenvironment. Several approaches are utilized to overcome this issue, such as co-culture of CLL cells with other cell types, supplementing culture media with growth factors, or setting up a three-dimensional (3D) culture. Previous studies have shown that 3D cultures, compared to conventional ones, can lead to enhanced cell survival and altered gene expression. 3D cultures can also give valuable information while testing treatment response in vitro since they mimic the cell spatial organization more accurately than conventional culture. In our study, we investigated the behavior of CLL cells in two types of material: (i) solid porous collagen scaffolds and (ii) gel composed of carboxymethyl cellulose and polyethylene glycol (CMC-PEG). We studied CLL cells' distribution, morphology, and viability in these materials by a transmitted-light and confocal microscopy. We also measured the metabolic activity of cultured cells. Additionally, the expression levels of MYC, VCAM1, MCL1, CXCR4, and CCL4 genes in CLL cells were studied by qPCR to observe whether our novel culture approaches lead to increased adhesion, lower apoptotic rates, or activation of cell signaling in relation to the enhanced contact with co-cultured cells. Both materials were biocompatible, translucent, and permeable, as assessed by metabolic assays, cell staining, and microscopy. While collagen scaffolds featured easy manipulation, washability, transferability, and biodegradability, CMC-PEG was advantageous for its easy preparation process and low variability in the number of accommodated cells. Both materials promoted cell-to-cell and cell-to-matrix interactions due to the scaffold structure and generation of cell aggregates. The metabolic activity of CLL cells cultured in CMC-PEG gel was similar to or higher than in conventional culture. Compared to the conventional culture, there was (i) a lower expression of VCAM1 in both materials, (ii) a higher expression of CCL4 in collagen scaffolds, and (iii) a lower expression of CXCR4 and MCL1 (transcript variant 2) in collagen scaffolds, while it was higher in a CMC-PEG gel. Hence, culture in the material can suppress the expression of a pro-apoptotic gene (MCL1 in collagen scaffolds) or replicate certain gene expression patterns attributed to CLL cells in lymphoid organs (low CXCR4, high CCL4 in collagen scaffolds) or blood (high CXCR4 in CMC-PEG).