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The ability of problem posing is very essential for the student’s. However, there are still many students who don't realize the importance of these abilities. This research describes the senior high school student’s ability in mathematical problem posing, especially in the material system of linear equations in three variables. Research data were collected from 7 student’s using written test and interview techniques. The validity of the data used triangulation methods by comparing the results of written tests and interviews. Data were coded, simplified, presented, and triangulated for the credibility and conclusion drawing. The results show that there were still very few students who have all three classifications of problem posing abilities, namely pre-solution posing, within-solution posing, and post-solution posing. Students who have the ability of pre-solution posing can ask questions based on the data provided and can arrange problem solving. Students who have the ability of within-solution posing can write what is given and asked of the problem, raise supporting questions which is relevant to the problem and arrange solutions to the supporting questions and problems that are given correctly. Students who have the ability of post-solution posing can raise similar mathematics problem after solving the problem. Students can also arrange solutions to problems that have been made. Teacher needs to practice pre-solution posing, within-solution posing, and post-solution posing to the students.

Chirality is a fundamental property of a molecule, and the significant progress in chirality detection and quantification of a molecule has inspired major advances in various fields ranging from chemistry, biology, to biotechnology and pharmacology. Chiral molecules have identical molecular formulas, atom-to-atom linkages, and bonding distances, and as such they are difficult to distinguish both sensitively and selectively. Today, most new drugs and those under development are chiral, which requires technological developments in the separation and detection of chiral molecules. Therefore, rapid and facile methods to detect and discriminate chiral compounds are necessary to accelerate advances in many research fields. The challenges in analysis stem from the obvious fact that chiral molecules have the same physical properties. Although significant progress on the detection of enantiomeric composition has been achieved in the past decade, in order to fully realize the capacity of chiral molecular interrogation, highly sensitive and selective, portable, and easy-to-use detection remains challenging because of the limitation of conventional techniques.Soft nanoarchitectonics is a new concept for the fabrication of functional soft material systems through harmonization of various actions including atomic/molecular-level manipulation, chemical reactions, self-assembly and self-organization, and their modulation by external fields/stimuli. Soft nanoarchitectonics has been widely used as a key enabling technology for integrating predefined molecular functionalities including electrochemical, optical, catalytic, or biological properties into biosensing devices, which provides exciting opportunities to design, assemble, and fabricate tailored nanosystems to enable new sensing strategies for chiral molecules.In this Account, we aim to concisely discuss how these molecule-inspired soft nanoarchitectonics work for enantioselective sensing. We will first outline the basic principle and mechanistic insights of the soft nanoarchitectonics approach for enantioselective sensing, and then we will describe the new breakthroughs and trends in the area that have been most recently reported by our groups and others. There will also be a discussion on the merits of soft nanoarchitectonics based sensing in comparison to conventional analytical methods. Finally, with this Account, we hope to spark new chiral molecule sensing strategies by fundamentally understanding chiral recognition and engineering soft nanoarchitectonics with programmable structures and predictable sensing properties.

Bilinear delamination failure criteria proposed by Reeder for mixed-mode (I–II) fracture of composite laminates has four limitations: require mixed-mode (I–II) fracture data by the more complex MMB test; determination of bilinear constants by two independent curve fits; failure of bilinear equations to intersect at $$\hbox {G}_{\mathrm{I}}^{\mathrm{m}}/\hbox {G}_{\mathrm{II}}^{\mathrm{m}}=1$$; and the data representation by $$\hbox {G}_{\mathrm{I}}^{\mathrm{m}}$$ versus $$\hbox {G}_{\mathrm{II}}^{\mathrm{m}}$$ instead of the conventional $$\hbox {G}_{\mathrm{c}}^{\mathrm{m}}$$ versus $$\hbox {G}_{\mathrm{II}}^{\mathrm{m}}/\hbox {G}_{\mathrm{T}}$$. Some of these limitations were overcome by limited input bilinear criteria (LIBC) proposed by Davidson and Zhao by replacing the MMB test data by DCB, ENF, and SLB (single leg beam) test data. But the LIBC retained the two discontinuous forms of the equations for no specific reason in a continuous material system. This paper eliminates the two equations by a single power law equation that covers the whole domain of fracture as in Benzeggagh and Kenane’s empirical equation. This simplified mixed-mode delamination fracture criterion we call “Limited Input B–K (LIBK) criterion in recognition of the works of Davidson and Zhao, and Benzeggagh and Kenane. The criterion was validated by a large number of test data in the literature.

Knowledge of the appearance of texture components and fibres in pole figures, in inverse pole figures and in Euler space is fundamental for texture analysis; an MTEX-based tool is presented to predict their appearance to enable subsequent quantitative texture analysis., Knowledge of the appearance of texture components and fibres in pole figures, in inverse pole figures and in Euler space is fundamental for texture analysis. For cubic crystal systems, such as steels, an extensive literature exists and, for example, the book by Matthies, Vinel & Helming [Standard Distributions in Texture Analysis: Maps for the Case of Cubic Orthorhomic Symmetry, (1987), Akademie-Verlag Berlin] provides an atlas to identify texture components. For lower crystal symmetries, however, equivalent comprehensive overviews that can serve as guidance for the interpretation of experimental textures do not exist. This paper closes this gap by providing a set of scripts for the MTEX package [Bachmann, Hielscher & Schaeben (2010). Solid State Phenom. 160, 63–68] that allow the texture practitioner to compile such an atlas for a given material system, thus aiding orientation distribution function analysis also for non-cubic systems.

The colloidal quantum dots (CQDs) are a promising nanometer-sized material system for optoelectronic applications due to the low cost, room temperature processing and substrate compatibility. Solution-processed technology such as spin-coating can make CQDs large-scale deposition on the substrates, whereas it inevitably brings about CQDs adherence to the edges even bottom of the substrates. As a result, the devices are not isolated and vertical leakage current occurs from the surface of CQDs to the substrates. In this work, two kinds of CQDs patterning techniques named etching-assisted patterning (EAP) and lift-off assisted patterning (LAP) have been put forward to significantly suppress the vertical current from several nanoampere to a few picoampere. Meanwhile, the CQDs photoconductor detectors have also been fabricated through these two patterning methods on the SiO2/Si substrates. Compared with un-patterning (UP) photodetectors, these two techniques both can enhance the photocurrent and promote the optoelectrical quality factors such as the responsivity and the specific detectivity, which make it possible to manufacture CQDs detector arrays and promote CQDs in optoelectronic applications.

The synthesis, electronic structure and temperature dependent transport properties of polycrystalline Cu1+xMn2-xInTe4 (x = 0, 0.2, 0.3) are reported for the first time. These quaternary chalcogenides were synthesized by direct reaction of the elements, followed by solid state annealing and hot press densification. The thermal conductivity is low for all specimens and intrinsic to the material system. Furthermore, the off-stoichiometry specimens illustrate the sensitivity of the transport properties to stoichiometry, with a greater than two-orders-of magnitude increase in carrier concentration with increased Cu content. First principles calculations of the electronic structure are also reported, and are in agreement with the experimental data. This fundamental investigation shows the potential towards further optimization of the electrical properties that, in addition to the intrinsically low thermal conductivity, provides a basis for further research into the viability of this material system for potential energy-related applications.

The article is devoted to the synergetic context of the system organization “chaos — order” in formation. The positions of the theories of chaos, catastrophes, complexity as the basis of the digital design are revealed. The principles of a new paradigm of formation are described.

Two-dimensional (2D) ferromagnetism is critical for both scientific investigation and technological development owing to its low-dimensionality that brings in quantization of electronic states as well as free axes for device modulation. However, the scarcity of high-temperature 2D ferromagnets has been the obstacle of many research studies, such as the quantum anomalous Hall effect (QAHE) and thin-film spintronics. Indeed, in the case of the isotropic Heisenberg model with finite-range exchange interactions as an example, low-dimensionality is shown to be contraindicated with ferromagnetism. However, the advantages of low-dimensionality for micro-scale patterning could enhance the Curie temperature (TC) of 2D ferromagnets beyond the TC of bulk materials, opening the door for designing high-temperature ferromagnets in the 2D limit. In this paper, we review the recent advances in the field of 2D ferromagnets, including their material systems, physical properties, and potential device applications.

Mechanophores (MPs) are a class of stimuli-responsive materials that are of increasing interest to engineers due to their potential applications as stress sensors. These mechanically responsive molecules change color or become fluorescent upon application of a mechanical stimulus as they undergo a chemical reaction when a load is applied. By incorporating MPs such as spirolactam, spiropyran, or dianthracene into a material system, the real-time stress distribution of the matrix can be directly observed through a visual response, ideal for damage and failure sensing applications. A wide array of applications that require continuous structural health monitoring could benefit from MPs including flexible electronics, protective coatings, and polymer matrix composites. However, there are significant technical challenges preventing MP implementation in industry. Effective strategies to quantitatively calibrate the photo response of the MP with applied stress magnitudes must be developed. Additionally, environmental conditions, including temperature, humidity, and ultraviolet light exposure can potentially impact the performance of MPs. By addressing these limitations, engineers can work to move MPs from the synthetic chemistry bench to the field. This review aims to highlight recent progress in MP research, discuss barriers to implementation, and provide an outlook on the future of MPs, specifically focused on polymeric material systems. Although the focus is on engineering MPs for bulk materials, a brief overview of mechanochemistry will be discussed followed by methods for activation and quantification of MP photo response (concentrating specifically on fluorescently active species). Finally, current challenges and future directions in MP research will be addressed.

Lead-free double perovskites have great potential as stable and nontoxic optoelectronic materials. Recently, Cs2AgBiBr6 has emerged as a promising material, with suboptimal photon-to-charge carrier conversion efficiency, yet well suited for high-energy photon-detection applications. Here, the optoelectronic and structural properties of pure Cs2AgBiBr6 and alkali-metal-substituted (Cs1−xYx)2AgBiBr6 (Y: Rb+, K+, Na+; x = 0.02) single crystals are investigated. Strikingly, alkali-substitution entails a tunability to the material system in its response to X-rays and structural properties that is most strongly revealed in Rb-substituted compounds whose X-ray sensitivity outperforms other double-perovskite-based devices reported. While the fundamental nature and magnitude of the bandgap remains unchanged, the alkali-substituted materials exhibit a threefold boost in their fundamental carrier recombination lifetime at room temperature. Moreover, an enhanced electron–acoustic phonon scattering is found compared to Cs2AgBiBr6. The study thus paves the way for employing cation substitution to tune the properties of double perovskites toward a new material platform for optoelectronics.

For potassium sodium niobate (KNN)-based ferroelectrics, a critical contradictory relationship exists where higher piezoelectricity is often achieved at the cost of their Curie temperature, and this severely restricts the practical applications of these ferroelectrics. How to resolve this contradiction is one of the urgent concerns in high-temperature piezoelectric applications. Herein, a new material system, 0.965K0.54Na0.46Nb1−xSbxO3-0.03Bi0.5Na0.5ZrO3-0.005BiFeO3 (KNNSx-BNZ-BF, 0 ≤ x ≤ 0.03), was obtained by compositional selection. A significant progress with respect to the simultaneous realization of a large d33 (∼505 pC N−1) and a high TC (∼285 °C) was achieved in this ferroelectric, which are superior to those of the KNN-based ferroelectrics reported to date. In addition, good temperature-independent strain properties were attained for this material due to its high TC values. Therefore, this KNN-based system may promote the practical application of lead-free materials in high-temperature fields.

A thorough study of phase separation in borosilicate glasses synthesized in the material system soda – colemanite – quartz sand was performed. The ranges of crystallization-resistant glasses and phase separation prone glasses were determined. It is shown that the complex raw material colemanite can be used to obtain glasses that are transparent or opaque in the bulk. The limiting content of raw materials in the material makeup of glass batches are recommended.

A systematic approach for assessing organic photovoltaic (OPV) materials for large scale production based on the efficiency, lifetime and cost has been developed. These parameters have been combined to establish a figure of merit, Ω, which determines the suitability of OPV materials for real-world large-scale implementation. As a case study, small scale device efficiency optimization, lifetime measurements and cost analysis of the P3HT:SF(DPPB)4, P3HT:ICxA and P3HT:PCBM systems was undertaken. The figure of merit developed through these case studies is also shown to be suitable for broader assessment of all materials incorporated into manufacturing of OPV technology. Despite the relatively large differences in optimized small scale device efficiency P3HT:PCBM was, with an Ω value of $8.3 per m2 per %, calculated as the most cost effective material system tested herein. This work demonstrates that small scale device efficiency alone is not a good proxy for the suitability of OPV material systems for large scale manufacturing and that the cost effectiveness figure of merit provides the more nuanced approach that is required.

This work presents a framework for collectively modeling shear viscosities of grouped polymeric materials. The viscosity model has been derived from the multi-modal White-Metzner constitutive equation. Simplification to the multi-modal viscosity has resulted in a viscosity model that controls gradual transition between two conventional viscosity models. It facilitates mathematical representation of multiple sets of viscosity data at the same time. A conventional shear viscosity function, which is common to the group, is multiplied by a material-specific function with one or two constants to form the collective viscosity model. The proposed framework has been applied to several polymeric systems such as polymers with varying molecular weight, polymer solutions with different concentrations, polymers with different filler loadings, and polymer blends with various composition ratios. It has been shown that the K-index in the proposed viscosity model and the variable in the material system such as concentration or compounding ratio can be correlated with each other to predict the viscosities of untested cases.

We report Al0.8In0.2As0.23Sb0.77 avalanche photodiodes with high gain ( $M>1300$ ) and low dark current at room temperature. Impact ionization coefficients for this material system are also extracted, indicating electron-dominant impact ionization. Low avalanche breakdown temperature dependence is demonstrated.

Biodegradable materials, including natural and synthetic polymers and hydrolyzable metals, constitute the main components of temporary, implantable medical devices. Besides the intrinsic properties of the materials, the most critical factor determining the successful clinical outcome of implantable and degradable devices is the host response, particularly the immune response, which largely depends on the material features and degradation mechanisms. In this Review, we first survey the state of the art in terms of materials options for use in biodegradable medical devices, focusing on degradation mechanisms and their control. In particular, we highlight silk, which is emerging as an important polymer, owing to its mechanical robustness, bioactive component sequestration, degradability without problematic metabolic products and biocompatibility. We then discuss the host response to these biodegradable materials in terms of dynamic tissue–implant interfaces. Next, we examine the clinical translation of three leading biodegradable material systems — natural and synthetic biodegradable polymers and biodegradable metals — and the related challenges in the context of orthopaedic fixation devices, cardiovascular stents and biodegradable electronic devices. Looking to the future, we propose updated material design strategies to improve the clinical outcomes for these biodegradable medical devices. Clinical outcomes with implantable and degradable devices largely depend on host response. This Review surveys material options and degradation mechanisms relevant to host responses to biodegradable devices, examines clinical translation of leading biodegradable materials and proposes updated material-design strategies to improve device performance.

In this current outlook, we critically review the most vital new outcomes in the field of rechargeable Li, Na and K-ion batteries. We deliberate current discoveries like the progress of electrospinning and their applications in future. Mainly, we discuss freestanding and binder-free electrodes structural and morphological effect when it undergoes long term cycling. Finally, this short review grants the up-to-date advancement on novel processing strategies of various carbon-based electrospun composites as anodes whose performance are similar with or even can beat that of the commercial anode material system.

The ceramic materials structure formation with the given esthetics-consumer properties is the most important mission of the modern production and should be based on the knowledge of physical and chemical processes, which are flowing past in masses based on the systems differing in the content of alkaline, alkaline-earth oxides and oxides of iron in clay raw materials.

Eine Antwort auf den großen und fortschreitenden Ressourcenverbrauch im Bauwesen können leichte und zugleich adaptive Lösungsansätze für Gebäudehüllen und -strukturen darstellen. Dazu müssen sie sowohl für schadensfreie Bauwerke mit passender Aufenthaltsqualität als auch für eine deutlich höhere Ressourceneffizienz sorgen. Beides gilt für den gesamten Lebensweg und trotz der für die Adaptivität benötigen zusätzlichen Betriebsenergie. Im Rahmen einer vorangegangenen Untersuchung adaptiver Leichtbaukonstruktionen für Fassaden wurde die bauphysikalische Funktionalität und Umweltwirkung einiger Beispiele auf Bauteilebene behandelt. Im hier vorliegenden Beitrag wird nun der Betrachtungshorizont auf die Raumebene erweitert, um z. B. neben Kennwerten für Wärme- und Feuchteschutz der Hülle auch die Behaglichkeit im Raum als Bewertungsmaßstab heranzuziehen. Natürlich erhöhen sich damit der Aufwand und die Komplexität der Bilanz, dafür lässt sich aber fundierter das Anwendungspotenzial adaptiver Alternativen einschätzen und über deren Weiterverfolgung entscheiden. Dazu werden drei herkömmliche, teils massive und teils leichte Konstruktionen, sowie vergleichbare adaptive Fassaden auf Raumebene untersucht und bewertet. Als wesentliche Bewertungskriterien gelten dabei quantitative Aussagen zur Erfüllung bauphysikalischer Anforderungen und zu ökologischen Umweltwirkungen. Im Ergebnis der methodenübergreifenden Forschung zeigt sich, dass adaptive Konstruktionen fallspezifisch, z. B. standortbezogen, beachtliches Potenzial zur Ressourcenreduktion ohne Funktionseinschränkungen mit sich bringen.

In recent years, there has been rapid progress on peridynamics. It has been applied to many different material systems, used for coupled field analysis and is suitable for multi-scale analysis. This study mainly focuses on peridynamic analysis for plate-type structures. For this purpose, a new peridynamic Kirchhoff plate is developed. The new formulation is computationally efficient by having only one degree of freedom for each material point. Moreover, it is based on the state-based peridynamic formulation, which does not impose any limitation on material constants. After presenting how to impose simply supported and clamped boundary conditions in this new formulation, several numerical studies are considered to demonstrate the accuracy and capability of the proposed formulation.

The dynamic fracture of high-stiffness and low-toughness materials such as soda-lime glass (SLG) typically involves crack initiation and growth prior to branching, underlying mechanics of which is not yet fully understood. Investigation of this issue using full-field optical techniques face numerous spatio-temporal challenges since crack speeds in these materials reach 1500 m/s or more and are accompanied by highly localized deformations. However, often it is tacitly assumed that most optical methods are equally capable of studying this challenging problem and it turns out not to be true. To this end, three prevalent optical techniques - transmission photoelasticity, 2D Digital Image Correlation (DIC) and transmission Digital Gradient Sensing (DGS) - are implemented concurrently to visualize crack-tip fields and quantify fracture characteristics associated with crack initiation, crack growth and macroscopic crack bifurcation in SLG plates subjected to nominally identical loading in three separate experiments. Each method is implemented in conjunction with ultrahigh-speed (1 Mfps) photography, flash/pulse illumination, and a modified-Hopkinson pressure bar for impact loading of specimens. The feasibility of measuring fracture parameters and imposed force histories along with the pros and cons of each approach for this material system are examined.

The march toward dimensional scaling and higher performance has led the semiconductor industry to consider nonplanar topologies and different material systems. These choices have led to an increase in the local power dissipation and, correspondingly, a rise in the local self-heating (SH). This article is a review of the history and trends of SH effects, the characterization techniques thereof, and the manifestations, sensitivities, and impacts of this heating on reliability mechanisms. Future pathways are also highlighted to indicate the challenges that exist for CMOS technologies.

The continuum elasticity model is applied to investigate quantitatively the growth features and nucleation mechanism of quantum dots, nanopits, and joint QD-nanopits structures in CdZnHgTe quasyternary material system. We have shown that for the CdZnHgTe solid solution deposited on the CdTe substrate, the sign of the critical energy and volume of island is changed at the critical strain of ɛ* = 0.006 and ɛ* = 0.009 (ɛ = Δa/a), It is assumed that the mechanism of the nucleation is changed from the growth of quantum dots to the nucleation of nanopits at ɛ = ɛ*. Obviously, at the small mismatch (ɛ ɛ*, when the energy barrier becomes negative and a large mismatch provides a low-barrier path for the formation of dislocations, the nucleation of pits becomes preferable energetically.

Prepreg composites find great applicability in e.g. the automotive and aerospace industries. A major challenge with this class of material systems is the accurate placement of a fabric that can be very tacky and hence sticks to the mold surface. In this study, automatic draping of entire plies of woven prepregs is considered. A robot end effector with a grid of actuated grippers is under development and it has the ability to position the plies onto double-curved mold surfaces of low curvature. The key issue is how the grippers of the end effector should move to achieve successful drapings of the plies that meet the quality requirements of the industry. In this study, an approximate ply model based on cables with bending stiffness is applied in an optimization framework where the gripper movements constitute the design variables. The optimization framework has taken inspiration from manual layup procedures. The numerical draping results indicate the usefulness of the cable model used in connection with the optimization framework. The next step is to implement the generated gripper trajectories on the physical robot system.

A highly hydrophobic sealing material system has been developed using high-temperature melt-quenching and sintering technologies for harsh environmental electrical connector package sealing applications. The sealing material properties can be varied by its phase structures, such as amorphous glass, crystalline monoclinic and tetragonal mixed phase, and covalent bond tetragonal phase, which are determined by a two-stage synthesizing process. The dilatometer measurements have found that the ambient coefficient of thermal expansion varies from ~5.8 to 7.1 ppm/°C while the coefficient of thermal expansion at its glass transition temperatures varies from ~7.0 to 9.0 ppm/°C. These coefficients of thermal expansion could provide not only wide options for integrating metal materials, such as Ti-alloy, Kovar, Inconel alloys, and Stainless Steels for making reliable electrical connector packages, but also enable the design of electrical connector packages with a safety factor of 3 performance, operable at 30KSI (30,000 PSI) pressure, and −100 −300°C harsh conditions while maintaining at least 5,000MΩ insulation resistances, for reliable signal, data, and electrical power transmissions.

The increasing demand for more weight efficient material systems has called upon for the development of polymer composites for various applications where special properties are anticipated like the...

Many living organisms have amazing control over their color, shape, and morphology for camouflage, communication, and even reproduction in response to interplay between environmental stimuli. Such interesting phenomena inspire scientists to develop smart soft actuators/robotics via integrating color-changing functionality based on polymer films or elastomers. However, there has been no significant progress in synergistic color-changing and shape-morphing capabilities of life-like material systems such as hydrogels. Herein, we reported a new class of bioinspired synergistic fluorescence-color-switchable polymeric hydrogel actuators based on supramolecular dynamic metal-ligand coordination. Artificial hydrogel apricot flowers and chameleons have been fabricated for the first time, in which simultaneous color-changing and shape-morphing behaviors are controlled by the subtle interplay between acidity/alkalinity, metal ions, and temperature. This work has made color-changeable soft machines accessible and is expected to hold wide potential applications in biomimetic soft robotics, biological sensors, and camouflage.

Transparent conducting oxide (TCO) is a promising material system for transparent electrodes, which is one of the most essential elements in current electronic and energy devices. In particular, In...

Machine learning (ML) has revolutionized disciplines within materials science that have been able to generate sufficiently large datasets to utilize algorithms based on statistical inference, but for many important classes of materials the datasets remain small. However, a rapidly growing number of approaches to embedding domain knowledge of materials systems are reducing data requirements and allowing broader applications of ML. Furthermore, these hybrid approaches improve the interpretability of the predictions, allowing for greater physical insights into the factors that determine material properties. This review introduces a number of these strategies, providing examples of how they were implemented in ML algorithms and discussing the materials systems to which they were applied.

Organoids are 3D cell culture systems that mimic some of the structural and functional characteristics of an organ. Organoid cultures provide the opportunity to study organ-level biology in models that mimic human physiology more closely than 2D cell culture systems or non-primate animal models. Many organoid cultures rely on decellularized extracellular matrices as scaffolds, which are often poorly chemically defined and allow only limited tunability and reproducibility. By contrast, the biochemical and biophysical properties of engineered matrices can be tuned and optimized to support the development and maturation of organoid cultures. In this Review, we highlight how key cell-matrix interactions guiding stem-cell decisions can inform the design of biomaterials for the reproducible generation and control of organoid cultures. We survey natural, synthetic and protein-engineered hydrogels for their applicability to different organoid systems and discuss biochemical and mechanical material properties relevant for organoid formation. Finally, dynamic and cell-responsive material systems are investigated for their future use in organoid research.

III–V semiconductors containing small amounts of nitrogen (“dilute nitrides”) are very promising material systems for optoelectronic applications. Devices based on dilute nitrides currently suffer ...

As current electronics makes a transition from bulky and rigid templates to lightweight and flexible ones, the emerging field of soft technology is set to revolutionize our daily life. Currently, polymer based templates dominate this field due to their excellent mechanical characteristics and low cost, but limited thermal budget and stabilities are the major technological bottlenecks resulting in poor performance and short duration of lifetime. Recently, the technology based on van der Waals heteroepitaxy on muscovite is considered as a promising solution to overcome these barriers at once. In this paper, the characteristics of muscovite and the mechanism of van der Waals heteroepitaxy will be introduced, after that, a variety of materials on muscovite via van der Waals heteroepitaxy and the efforts on practical applications are reported. With the outlook of material science and help of advanced measurements, the evidence of heteroepitaxy of muscovite and overlayers has been deeply analyzed. Moreover, various measurements of properties was carried under bending conditions to demonstrate the mechanical stability and reliability. Through this review, we pave the path to develop more material systems on muscovite to make MICAtronics completely.

Atomic catalysts (AC) as the frontier in atomic catalyst have attracted tremendous attention in recent electrocatalyst research. The performance of ACs strongly depends on the electronic interaction between the atoms and support. To supply a direct strategy for discovering more promising electrocatalysts, we propose a comprehensive mapping study of anchoring transition metals on the graphdiyne (GDY). The electron transfer ability and zero-valence stability are quantified based on the redox process between surface metal and GDY support. The different electron transfer number and directions between the transition metals and GDY are also compared, in which the initial one-electron transfer is the most difficult. Among all the TMs, Co, Pd and Pt have displayed the exceptional stability of zero-valence catalyst based on the evident energy barrier difference between losing electrons and gaining electrons. Experimental results support the remarkable performance of our screened candidates, which have opened a new possibility to achieve novel high-performance zero-valence ACs. Moreover, we outlook the introduction of the deep-learning algorithm in the future advanced mapping strategy for achieving more complicated ACs. This work not only supplies innovative electrocatalyst candidates but also exhibits an innovative approach for studying the electrocatalysts that can further apply to more material systems.

Two-dimensional (2D) material nanocomposites have emerged as a material system for discovering new physical phenomena and developing novel devices. However, because of the low density of states of most two-dimensional materials such as graphene, the heterostructure of nanocomposites suffers from an enhanced depletion region, which can greatly reduce the efficiency of the charge carrier transfer and deteriorate the device performance. To circumvent this difficulty, here we propose an alternative approach by inserting a second 2D mediator with a heavy effective mass having a large density of states in-between the heterojunction of 2D nanocomposites. The mediator can effectively reduce the depletion region and form a type-II band alignment, which can speed up the dissociation of electron-hole pairs and enhance charge carrier transfer. To illustrate the principle, we demonstrate a novel stretchable photodetector based on the combination of graphene/ReS

The purpose of this study was to determine whether using the TPS learning model by using LKS can improve student learning outcomes in the material system linear equation two variable in class X Senior High Public School 2 of Pematangsiantar. The type of research used is classroom action research with 2 cycles. Subjects of class X-IPA 7. On the implementation of the first cycle of action, the result of the analysis of tests of students at the moderate (≥ 65) category in a classical manner were still not achived because only 52.78% of students were completed, with a grade average 65.00. After the implementation of the second cycle of action, the learning outcomes of students in the medium minimum category (≥ 65) have been achived classically, namely 86.11% with an average value 73.75. The increase in students’ mathematics learning outcomes from cycle I to cycle II was 21.11%. Based on the result of the above research it can be concluded that the application of the TPS learning model using LKS can improve student learning outcomes.Keywords: Laerning Outcomes, Think Pair Square (TPS), LKS

Dendrite growth affects material systems across applications as diverse as lithium batteries, organic light emitting diodes, turbine blades, and biological sensors. Their unique crystal structure a...

This paper presents an experimental study for the assessment of a three-dimensional Progressive Fatigue Damage Model (PFDM) with a carbon fiber/epoxy (AS4/3501–6) material system. Specimens with a central circular hole were selected to represent notched composite structures. Digital Image Correlation (DIC) was used to monitor the surface strain evolution throughout the fatigue lifetime. The PFDM model was implemented in the commercial finite element software ABAQUS using the user material (UMAT) utility. Residual stresses from the composite manufacturing cycle are included in the fatigue damage modeling. Results are presented that compare experimental and predicted strain distributions and fatigue lives. Comparisons between the experimental and simulated response highlight the value of the PFDM model while demonstrating its shortcomings.

Nowadays, biomaterials have attained great importance in medical sector owing to the urgent requirement of the material systems which can be suitable for different sorts of human body treatments. Among the various biomaterials available, commercially, polymeric materials occupy great importance because of their near-to-organ characteristics, biocompatibility, corrosion resistance, and other essential mechanical features. The current applications of biopolymers include scaffolding, load-bearing implants, intraocular lenses, artificial heart valves, cardiovascular prostheses, cardiopulmonary bypass, hemodialysis, and dental and orthopedic applications. Although there exist numerous established fabrication routes for biopolymers, yet, their post processing is often required in order to achieve required geometrical and topographical performances. Therefore, machining of the processed biopolymers is often required. The aim of this article was to present a crisp review of the machining of different biopolymers. Further, being an ultraprecision machining operation, specific attention has been paid on the diamond turning technique as well as a case study has been performed to study the effect of process parameters on the resulting characteristics. Overall, the current work will provide a unique platform which could be helpful for young biomedical engineers and scientists focusing on precision surface engineering.

Many materials systems comprise complex structures where multiple materials are integrated to achieve a desired performance. Often in these systems, it is a combination of both the materials and their structure that dictate performance. Here the authors layout an integrated computational–statistical–experimental methodology for hierarchical materials systems that takes a holistic design approach to both the material and structure. The authors used computational modeling of the physical system combined with statistical design of experiments to explore an activated carbon adsorption bed. The large parameter space makes experimental optimization impractical. Instead, a computational–statistical approach is coupled with physical experiments to validate the optimization results.

Titanium matrix composites (TMCs) offer high specific strength and stiffness compared with steel and nickel-base materials. High-temperature TMCs can offer up to 50% weight reduction relative to monolithic superalloys while maintaining equivalent strength and stiffness in jet engine propulsion systems. Regardless of the reinforcements are continuous fibres or discontinuous particulates, the unique properties of TMCs have thrust them to the forefront of extensive research and development programmes around the world. Even though TMCs are one of the most studied and sought-after material systems, useful information about their properties, fabrication methods and design is scattered in the literature. This review covers important research work that has led to the advances in TMCs material systems. It also provides comprehensive details about common reinforcements, manufacturing processes, and reviews static and dynamic properties of some common TMCs. The review also presents common industrial applications of TMCs and highlights the promising outlook of TMCs.

Bulk fracture and secondary caries are the two main problems causing failures and shortening the lifetime of dental resinous restorations. This article reviews recent research on self-healing dental and biomedical materials. This includes the development of self-healing dental resin composites and adhesives, combining self-healing with calcium phosphate nanoparticles in the resins for tooth lesion remineralization, and adding antibacterial monomer into self-healing resins to suppress oral biofilm grows and acid production. Furthermore, since the oral environment experiences saliva and drinks, this paper also reviews research on the self-healing of dental resins while being submerged in an aqueous environment, and the effect of long-term water-aging time from 1 day to 6 months on the self-healing capability. The new class of materials have demonstrated excellent self-healing efficacy in various material systems including bonding agents, composites and cements. They could heal cracks, regain load-bearing ability, inhibit oral pathogens, reduce or eliminate biofilm acids, raise biofilm pH to protect the teeth, and regenerate lost tooth minerals. Furthermore, their effects were indicated to be durable and long-lasting. While most of the recent publications on self-healing dental resins are from our group, this article also reviews publications from other researchers. The novel class of dental materials with triple benefits of self-healing, antibacterial and remineralization capabilities offer the much-needed improvements to address the two main reasons for restoration failures: fracture and secondary caries. They are expected to have potential for a wide range of dental and biomedical applications to overcome the current challenges and prolong the restoration life.

Bio-inspired staggered platelets reinforced composites exhibit excellent mechanical properties and thus have been widely investigated. However, the strength of these materials can hardly be estimated accurately by previous models except for some special cases. Therefore, we propose a novel model to predict the strength of composites with regularly and randomly staggered platelets. The model can account for the effects of platelet overlap, platelet offset, and normal stress at platelet ends, which are ignored or partially ignored in previous models. The model is then applied to predict the tensile strength for various platelet-matrix material systems with various platelet distributions, and shows much better agreements with simulation and experimental results than previous models, which indicates that the present model can significantly improve the accuracy of the estimation on composite tensile strength and greatly broaden the application scope of the estimation.

The crack tip stress intensity factor in a homogeneous isotropic material was easily experimentally evaluated via the caustics method. With respect to the bi-material orthotropic/isotropic system, it is not possible to directly evaluate the interfacial crack stress intensity factor via traditional caustics theory. In the study, theoretical caustics and initial curves at interfacial cracks of orthotropic/isotropic bi-material system were simulated based on caustics parametric equations surrounding the interfacial crack tip derived via the principle of the transmission caustics. To verify the theoretical caustics equation, a dynamic caustics experiment and FEM method under an impact load with the orthotropic/isotropic bi-material system were conducted. The KID evaluated by the dynamic caustics equation agreed well with the FEM results. The results provide an integrated theoretical foundation with respect to the application of the caustics equation on the bi-material interfacial crack problem.

Heterogeneous materials with tailored, site-specific physical properties, ubiquitously found in biological systems, can reach optimal performances in applications. Compared to homogeneous materials or composite materials with random, disordered microstructures, materials with locally addressable properties achieve higher strength at lower density, or record-high shock absorption properties. A classic example of tailored, heterogeneous materials are functionally graded materials or materials where stiffness variations in bulk are controllable. However, current methods to locally control stiffness in a solid are mostly limited to geometrical variation of architected micro-structures, or to the creation of multi-material composites. Here, a novel approach to program stiffness variations within a single material system is presented. By subsequent exposure of a pre-crosslinked polymeric matrix using two-photon polymerization, arbitrary three-dimensional architectures with locally addressable stiffness variations are fabricated. Furthermore, the extension of the hierarchical level of three-dimensional micro-architectures by property variations in the constituent material is demonstrated. The programmable stiffness variations, in the sub-micron range, are either continuous or sharply confined, with a stiffness increase of up to 200% compared to the pre-crosslinked matrix. This site-specific control of stiffness and internal architecture opens the door for engineering materials with unprecedented mechanical properties.

Antimicrobial agents based on organic materials have limited use owing to their low heat resistance and short lifetimes. Therefore, various studies on antibacterial agents that are based on inorganic material systems are increasingly being performed to supplement them. In this study, Cu@SiO₂ core-shells are fabricated using Cu cores and SiO₂ shells, and are known to have antimicrobial effects. The core-shell was coated with SiO₂ using the sol-gel method. Experiments were conducted using X-ray diffraction and the shaking flask method (KS J 4206) to evaluate the characteristics of the core-shell. In the case of X-ray diffraction, both the Cu core and the core-shell fabricated using the sol-gel process were characterized. Escherichia coli and Staphylococcus aureus were evaluated using the KS J 4206 method for their antibacterial properties. Through this study, it is confirmed that a Cu@SiO₂ core-shell can be fabricated via the sol-gel method, and that Cu with a core-shell structure has antibacterial effects.

Van der Waals (vdW) deep-UV (DUV) nonlinear optical (NLO) crystal is an important material system recently developed. Herein, we review its concept and original intention, and then summarized the discovery process of related materials, including the role of A-site cations and the resulting two-/one-dimensional vdW DUV NLO systems. Finally, we evaluate the practical DUV NLO performance and prospected the opportunities and challenges.

The technical transfer of plant movement principles offers vast potentials for the development of novel, autonomously actuated structures. In article number 2100411 by Tiffany Cheng, Achim Menges, and co‐workers introduces a design and material programming approach for 4D‐printing adaptive material systems through a case study of biomimetic design. Based on the force generating mechanism of the air potato (Dioscorea bulbifera), the authors demonstrate the manufacture of a self‐tightening orthotic device. [Image: see text]

Many existing clinical treatments are limited in their ability to completely restore decreased or lost tissue and organ function, an unenviable situation only further exacerbated by a globally aging population. As a result, the demand for new medical interventions has increased substantially over the past 20 years, with the burgeoning fields of gene therapy, tissue engineering, and regenerative medicine showing promise to offer solutions for full repair or replacement of damaged or aging tissues. Success in these fields, however, inherently relies on biomaterials that are engendered with the ability to provide the necessary biological cues mimicking native extracellular matrixes that support cell fate. Accelerating the development of such "directive" biomaterials requires a shift in current design practices toward those that enable rapid synthesis and characterization of polymeric materials and the coupling of these processes with techniques that enable similarly rapid quantification and optimization of the interactions between these new material systems and target cells and tissues. This manuscript reviews recent advances in combinatorial and high-throughput (HT) technologies applied to polymeric biomaterial synthesis, fabrication, and chemical, physical, and biological screening with targeted end-point applications in the fields of gene therapy, tissue engineering, and regenerative medicine. Limitations of, and future opportunities for, the further application of these research tools and methodologies are also discussed.