Dimensional Materials Research Articles

Teacher agency and ICT affordances in classroom-based language assessment: The return to face-to-face classes after online teaching

Recent research on classroom-based assessment (CBA) during the COVID-19 pandemic has examined language teachers’ strategic responses to challenges in online teaching. However, there is still a paucity of empirical research on their CBA practices supported by information and communication technology (ICT) during the return to face-to-face (f2f) classes. Moreover, most studies on CBA during and after the pandemic have focused on secondary or higher education, leaving young learner contexts underexplored. Thus, this study investigated how two primary school English teachers in South Korea exercised their agency to implement ICT-afforded CBA to address challenges in returning to f2f classes, grounded in an ecological perspective. It further explored mediating factors that influenced their agency in both temporal and relational aspects. Observations, interviews, and reflection papers revealed four main themes regarding their agency enactment in identifying ICT affordances for CBA, which were linked to individual factors in their agency enactment, including their pedagogical beliefs, ICT use experiences, identity, and professional development. The cultural (e.g., national curriculum), structural (e.g., student wellness and parental voices), and material dimensions (e.g., institutional support of teacher training) also influenced their agency enactment. This study provides both theoretical and practical implications for ICT-afforded CBA in the post-pandemic era.

Analysis on the Design and Timeliness of English Teaching Models in Colleges and Universities under the Background of Informatization

Abstract The informationization era has accelerated people’s learning changed their thinking and cognitive styles, and the English teaching mode is also evolving and innovating. The purpose of this paper is to develop an English learning behavior analysis model, select an improved K-means algorithm for clustering learners, and examine the association rules between learning behaviors and learning effects. In addition, based on the sequence of learners’ behaviors, the article also combines the EduHawkes prediction model with multi-type features to quantify the learning effect in terms of learning engagement and predict the learning effect of students. The blended English teaching model is designed by combining learning behavior analysis and learning effect prediction models. In the experimental study of the timeliness of the English teaching model, the dimensions of students’ English literacy in terms of thinking quality, learning ability, and language ability showed significant differences before and after the experiment (P<0.05). In the evaluation of teaching methods, the dimensions of teaching materials, teaching tools, evaluation of learning outcomes assessment methods, and evaluation of teaching level showed significant differences (P<0.05). The English teaching model proposed in this paper is timely.

Single Molecular Semi-Sliding Ferroelectricity/Multiferroicity.

In recent years, the unique mechanism of sliding ferroelectricity with ultralow switching barriers has been experimentally verified in a series of 2-dimensional (2D) materials. However, its practical applications are hindered by the low polarizations, the challenges in synthesis of ferroelectric phases limited in specific stacking configurations, and the low density for data storage since the switching process involves large-area simultaneous sliding of a whole layer. Herein, through first-principles calculations, we propose a type of semi-sliding ferroelectricity in the single metal porphyrin molecule intercalated in 2D bilayers. An enhanced vertical polarization can be formed independent on stacking configurations and switched via sliding of the molecule accompanied by the vertical displacements of its metal ion anchored from the upper layer to the lower layer. Such semi-sliding ferroelectricity enables each molecule to store 1 bit data independently, and the density for data storage can be greatly enhanced. When the bilayer exhibits intralayer ferromagnetism and interlayer antiferromagnetic coupling, a considerable difference in Curie temperature between 2 layers and a switchable net magnetization can be formed due to the vertical polarization. At a certain range of temperature, the exchange of paramagnetic-ferromagnetic phases between 2 layers is accompanied by ferroelectric switching, leading to a hitherto unreported type of multiferroic coupling that is long-sought for efficient "magnetic reading + electric writing".

Chemical exfoliation of 1-dimensional antiferromagnetic nanoribbons from a non-van der Waals material.

As the demand for increasingly varied types of 1-dimensional (1D) materials grows, there is a greater need for new methods to synthesize these types of materials in a simple and scalable way. Chemical exfoliation is commonly used to make 2-dimensional (2D) materials, often in a way that is both straightforward and suitable for making larger quantities, yet this method has thus far been underutilized for synthesizing 1D materials. In the few instances when chemical exfoliation has been used to make 1D materials, the starting compound has been a van der Waals material, thus excluding any structures without these weak bonds inherently present. We demonstrate here that ionically bonded crystals can also be chemically exfoliated to 1D structures by choosing KFeS2 as an example. Using chemical exfoliation, antiferromagnetic 1D nanoribbons can be yielded in a single step. The nanoribbons are crystalline and closely resemble the parent compound both in structure and in intrinsic antiferromagnetism. The facile chemical exfoliation of an ionically bonded crystal shown in this work opens up opportunities for the synthesis of both magnetic and non-magnetic 1D nanomaterials from a greater variety of starting structures.

Montmorillonite (MMT) nanoclay in smart coatings for corrosion protection of metal alloy: a brief review

Montmorillonite (MMT) nanoclay is a natural raw material naturally occurring 2-dimensional lamellar silicate material. Many advantages of MMT clay are low cost, high dispersion properties, good mechanical properties, hydrophobic, good shield against corrosive media, non-toxic, easily accessible, and most importantly, it is natural. MMT was mainly used as an additive with other active smart materials to enhance the excellent properties for smart coatings. However, there is not much research done from the last 5 years regarding MMT in smart coating for corrosion protection. The discussion regarding MMT for corrosion protection is also contradict between each research. This paper provides a brief review on MMT clay in smart coatings and its advantages for corrosion protection for the last 5 years. There are also some drawbacks of MMT in smart coatings discussed at the end. Further research needs to be done as MMT has more potential that can be used in the real-world industries and to clarify the contradiction of statement existed in much research.

Investigation of the lattice thermal transport properties of Janus XClO (X = Cr, Ir) monolayers by first-principles calculations.

In the context of the global energy crisis, the development of high-performance heat transport devices within nano scales has become increasingly important. Theoretical discovery and evaluation of novel structures with high performance in thermal conductivity by affordable calculations could provide significant instructions for experimental studies focusing on thermoelectric device development. For 2-dimensional (2D) functional materials, their heat transport efficiency is correlated with their electronic properties and structural features. In this study, we computationally investigated the heat transport within Janus XClO (X = Cr, Ir); its structural and electronic properties were well solved by first-principles calculations. Furthermore, to evaluate thermodynamics stability and applicability, ab initio molecular dynamics (AIMD) simulations are conducted. Through a benchmarking study upon these XClO monolayers with different compositions, we noticed that their heat transport efficiency is associated with the percentage of doped magnetic atoms. The theoretical insights provided by this study are highly instructive for future experimental studies focusing on thermal device development.

DFT study of Ti3C2 MXene nanosheets as a drug delivery system for 5-fluorouracil.

In this study, we modeled a drug delivery system consisting of Ti3C2 MXene nanosheets as a carrier and 5-fluorouracil (FU) as a selected drug molecule using density functional theory (DFT) computations. During the adsorption procedure, electronic, magnetic and structural properties were calculated. Our results showed that the adsorption of FU drugs on the Ti3C2 surface is thermodynamically favorable. Our spin-polarized calculations also determined that the magnetization of Ti3C2 after FU adsorption does not change significantly, which is an important factor for magnetic hyperthermia and drug delivery. In addition, our calculations indicate that in the slightly acidic environment of tumor tissue, FU could start to be released (by increasing distance from the MXene surface and then instability of the complex) from the Ti3C2 surface without any substantial change in the structural properties. This study could provide a deep understanding of the interaction mechanism of 2-dimensional (2D) MXene materials with drugs at the atomistic scale and have an important contribution to the discovery and application of novel 2D materials as drug delivery systems.

Precise synthesis of graphene by chemical vapor deposition.

Graphene, a typical representative of the family of two-dimensional (2D) materials, possesses a series of phenomenal physical properties. To date, numerous inspiring discoveries have been made on its structures, properties, characterization, synthesis, transfer and applications. The real practical applications of this magic material indeed require large-scale synthesis and precise control over its structures, such as size, crystallinity, layer number, stacking order, edge type and contamination levels. Nonetheless, studies on the precise synthesis of graphene are far from satisfactory currently. Our review aims to deal with the precise synthesis of four critical graphene structures, including single-crystal graphene (SCG), AB-stacked bilayer graphene (AB-BLG), etched graphene and clean graphene. Meanwhile, existing problems and future directions in the precise synthesis of graphene are also briefly discussed.

Tunable Electronic Structures upon Janus In2Ge2X3Y3 (X, Y =S, Se and Te) Monolayers by External Fields

Two dimensional (2D) materials with ultrathin atomic thicknesses and intriguing properties have aroused tremendous attention. Inspired by emerging researches on 2D InGeX3 (X =S, Se and Te), the novel properties...

Simple preparation of 1D hierarchical magnetic CNTs/hollow porous macroscopic carbon fiber composites for efficient microwave absorption

1D self-supporting CNT-loaded hierarchical hollow porous carbon fibers with excellent microwave absorption properties were prepared using low-cost polypropylene fibers as precursors.

Electrostatic co-assembly of FePS3 nanosheets and surface functionalized BCN heterostructures for hydrogen evolution reaction.

Advances in the hydrogen evolution reaction (HER) are intricately connected with addressing the current energy crisis and quest for sustainable energy sources. The necessity of catalysts that are efficient and inexpensive to perform the hydrogen evolution reaction is key to this. Following the ground-breaking discovery of graphene, metal thio/seleno phosphates (MPX3: M - transition metal, P - phosphorus and X - S/Se), two dimensional (2D) materials, exhibit excellent tunable physicochemical, electronic and optical properties, and are expected to be key to the energy industry for years to come. Taking this into account, a facile time-effective electrostatic restacking synthesis procedure has been followed to synthesize a 2D/2D heterostructure (FePS3@BCN) involving FePS3, one of the prominent MPX3 materials, with borocarbonitride (BCN), for hydrogen evolution reaction (HER). The piled up nanosheets of FePS3 and BCN are held together by an electrostatic force, and display extreme robustness under the harsh conditions of HER application. The amalgamated electrocatalyst achieved an overpotential of 187 mV at a current density of 10 mA cm-2 with a shallow Tafel slope of 41 mV dec-1, following the Volmer-Heyrovsky mechanism. The resilience of the electrocatalyst has been examined through chronoamperometric testing for long term stability, and it is stable for more than 14 hours, which shows the excellent electrocatalytic activity for hydrogen evolution reaction owing to the strategic approach to the catalyst design, the use of numerous electrochemically active sites, large surface area and a barrier-free channel for quick ion transfer.

1D hollow tubular/2D nanosheet hybrid dimensional porous carbon prepared by one-step carbonization using natural minerals as templates for supercapacitors.

The reasonable construction of one-dimensional (1D)/two-dimensional (2D) hybrid dimensional porous carbon materials with complementary advantages and disadvantages is an important approach to addressing the structural and performance deficiencies of single carbon materials, while also significantly improving the electrochemical performance of super-capacitors. In this study, 1D hollow tubular/2D nanosheet hybrid dimensional porous carbon was synthesized through one-step carbonization using 1D fibrous brucite and 2D layered magnesium carbonate hydroxide as templates. By adjusting the feed ratio of 1D fibrous and 2D layered templates, the morphology, pore structure and specific surface area (SSA) of the prepared 1D hollow tubular/2D nanosheet hybrid dimensional porous carbon were controlled. The prepared hybrid dimensional porous carbons were characterized using scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and nitrogen adsorption-desorption. And their electrochemical performance was also studied by cyclic voltammograms (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS). The results show that the use of templates with different dimensions significantly influences the morphology, pore structure, SSA and electrochemical performance of the synthesized hybrid dimensional porous carbon. The hybrid dimensional porous carbon (3F) exhibits a high specific capacitance and excellent cycling stability. 3F demonstrates the specific capacitance of 245.3 F g-1 at 1 A g-1. Furthermore, the capacity retention rate remains as high as 93.4% after 8000 cycles at 10 A g-1. This work reveals that hybrid dimensional porous carbon composed of 1D hollow carbon tubes and 2D carbon nanosheets has great potential for use in supercapacitor electrode materials.

Characterization and Growth Mechanisms of Low Dimensional InP Materials

Characterization and Growth Mechanisms of Low Dimensional InP Materials

Emerging application of 2D materials for dendrite-free metal batteries

Metal batteries using lithium, sodium, potassium, zinc, etc., as anodes have garnered tremendous attention in rechargeable batteries because of their highly desirable theoretical energy densities. However, large-scale application of these metal batteries is impeded by dendrite growth on the anode surface, which may penetrate the separator, leading to battery failure. Two dimensional (2D) materials featured by excellent mechanical strength and flexibility, tunable electronic properties and controllable assembly are promising materials for the construction of dendrite-free metal batteries. In this review, we summarize recent advancements of 2D materials for their potential use in critical components of dendrite-free batteries used as: (1) a host or artificial solid-electrolyte for metal anodes; (2) a solid electrolyte or modifier for electrolyte; and (3) an enhancement component for separators design. We conclude that 2D materials hold great promise for tackling the problems associated with dendrite formation by functioning as mechanical reinforcement and metal deposition regulators, along with improved safety, performance, and durability of batteries. Finally, this review discusses new perspectives and future directions in the field of 2D materials towards safe, high-energy metal batteries.

A review of various dimensional superwetting materials for oil-water separation.

In recent years, the application and fabrication technologies of superwetting materials in the field of oil-water separation have become a research hotspot, aiming to address challenges in marine oil spill response and oily wastewater treatment. Simultaneously, the fabrication technologies and related applications of superwetting materials have been increasingly diversified. This paper systematically reviews the sources and hazards of oily wastewater and oil-water emulsions, several traditional oil-water separation methods, and their limitations, thereby highlighting the advantages of superwetting materials. Additionally, this paper provides an overview of the fundamental theories of wetting and conducts a microanalysis of the penetration mechanism based on Laplace pressure at the gas-liquid-solid three-phase interface. Following this, the latest advances in superwetting oil-water separation materials are elucidated, focusing on five categories: (i) superhydrophobic-superoleophilic materials; (ii) superhydrophilic-underwater superoleophobic materials; (iii) superhydrophobic-superoleophobic materials; (iv) "special" superwetting materials; and (v) smart switchable superwetting materials. This paper innovatively discusses these materials from the perspectives of two-dimensional and three-dimensional materials, deeply studying the mechanisms of oil-water separation and using data to quantify the separation efficiency. Comparative discussions are conducted on the materials from various dimensions, including different substrates, innovations in existing technologies, and fabrication methods as discussed in various articles, followed by corresponding summaries. Finally, the existing shortcomings and challenges of current superwetting materials are summarized, and prospects are proposed. We firmly believe that developing low-cost, stable, environmentally friendly, and practical large-scale superwetting oil-water separation materials will have broad application prospects and potential in the future.

A mini review on two dimensional (2D) materials for energy storage applications

The discovery of new class of nanomaterials referred to as two-dimensional (2D) materials create extensive attention due to their unique features such as very small size, high anisotropy, high strength, high young’s modulus and excellent flexibility. The addition of numerous 2D materials, including black phosphorous, transition metal oxides, MXene materials, boron nitrides and others, were discovered following by the graphene. The most common 2D material are widely used in energy storage devices due to its large specific surface area, large lateral size and superior performance and adaptability. Due to the environmental, conductive, and catalytic uses, MXene materials are also attaining great attention. The synthesis and applications of two-dimensional materials like graphene and MXene, are the primary focus of this review paper.

Study of mechanical properties of RPV base and weld material using SPT technique

Small Punch Test (SPT) is one of the miniature test techniques used for evaluating tensile properties when limited dimension of material is available for standard mechanical test or handling of large specimen is difficult, especially while dealing with irradiated materials. In order to use SPT for determination of mechanical properties, it is crucial to establish correlation coefficients by comparing results obtained by SPT with that from standard tensile tests. Present work involves developing correlation coefficients and evaluation of tensile properties of reactor pressure vessel (RPV) steel using SPT technique. Specimen dimensions used for SPT was 10x10x0.5 mm3. These specimens were prepared from Charpy V-Notch specimens, which were earlier subjected to standard impact testing. Correlation coefficient for RPV material was established by comparison of SPT data with the tensile properties obtained using standard tensile test. Subsequently, SPT data was acquired on RPV thermal material and tensile properties were obtained using the correlation coefficient for validation. This paper describes the SPT set-up used during the current studies and methodology used for establishing the correlation coefficient on RPV base material.

Multilayer MoS 2 Photodetector with Broad Spectral Range and Multiband Response

As a typical 2-dimensional material, molybdenum disulfide (MoS 2 ) has atomic thickness in longitudinal size, showing unique optical and electrical properties. MoS 2 has become a research hotspot in the field of photodetection. The properties of MoS 2 devices are highly dependent on their material characteristics, device structures, and fabrication techniques. Therefore, their photoresponse characteristics may be determined by multiple physical effects, which contribute to the development of MoS 2 -based broadband photodetectors. Here, we present an experimental study on the broadband MoS 2 photodetector ranging from 410 to 1,550 nm, obviously wider than that of conventionally reported MoS 2 photodetectors. Our results indicate that the performance of the MoS 2 device is dependent on the fabrication procedures. Under the optimal process, the maximum responsivity is 33.75 A W −1 and the corresponding specific detectivity is 6.1 × 10 11 cm Hz 1/2 W −1 at 480-nm illumination. Through a series of electrical and optoelectronic experimental analysis, the working mechanisms of multiband photoresponse of the MoS 2 device are clarified.

Mechanistic Insights into CO2 Activation on Pristine, Vacancy-containing and Doped Goldene: A Single-Atom Layer of Gold

Goldene, a one-atom-thick gold sheet, is an emerging graphene-like flat 2-dimensional material. In this study, the geometrical and electronic properties, as well as CO2 adsorption characteristics, of the pristine,...

Electrochemical exfoliation of 2D materials beyond graphene.

After the discovery of graphene in 2004, the field of atomically thin crystals has exploded with the discovery of thousands of 2-dimensional materials (2DMs) with unique electronic and optical properties, by making them very attractive for a broad range of applications, from electronics to energy storage and harvesting, and from sensing to biomedical applications. In order to integrate 2DMs into practical applications, it is crucial to develop mass scalable techniques providing crystals of high quality and in large yield. Electrochemical exfoliation is one of the most promising methods for producing 2DMs, as it enables quick and large-scale production of solution processable nanosheets with a thickness well below 10 layers and lateral size above 1 μm. Originally, this technique was developed for the production of graphene; however, in the last few years, this approach has been successfully extended to other 2DMs, such as transition metal dichalcogenides, black phosphorous, hexagonal boron nitride, MXenes and many other emerging 2D materials. This review first provides an introduction to the fundamentals of electrochemical exfoliation and then it discusses the production of each class of 2DMs, by introducing their properties and giving examples of applications. Finally, a summary and perspective are given to address some of the challenges in this research area.