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The estimation of human pose has been an important field of study for the area of computer vision. Due to its significant applications in various important fields such as human computer interaction, action recognition, video surveillance, threat prediction, etc., it has been in the focus of researchers mainly. Dramatic effects of deep learning techniques have resulted in major steps and important developments in estimating human poses. We are proposing a fast and efficient deep learning approach to detecting 2D pose from a monocular image by multiple persons. The method uses a Vector Field (PVF) part affinity, which learns how well the limbs have been connected. The architectural design provides a global pixel-level interpretation of the number of people by enabling a bottom-up approach that maintains high accuracy in real time. The architecture has been designed to use two branches of a convolutional neural network (CNN) with sequential prediction to understand and reference part locations around each other. Successfully, with the help of the MS COCO human pose dataset, we have implemented our approach.

One of the main capabilities of atom probe tomography (APT) is the ability to not only identify but also characterize early stages of precipitation at length scales that are not achievable by other techniques. One of the most popular methods to identify nanoscale clustering in APT data, based on the density-based spatial clustering of applications with noise (DBSCAN), is used extensively in many branches of research. However, it is common that not all of the steps leading to the selection of certain parameters used in the analysis are reported. Without knowing the rationale behind parameter selection, it may be difficult to compare cluster parameters obtained by different researchers. In this work, a simple open-source tool, PosgenPy, is used to justify cluster search parameter selection via providing a systematic sweep through parameter values with multiple randomizations to minimize a false-positive cluster ratio. The tool is applied to several different microstructures: a simulated material system and two experimental datasets from a low-alloy steel . The analyses show how values for the various parameters can be selected to ensure that the calculated cluster number density and cluster composition are accurate.

Analysis of multidimensional in-depth thermal response for the phenolic impregnated carbon ablator (PICA)/CV-1144-0 material system in NASA Langley Research Center Hypersonic Materials Environmenta...

We report Al0.3InAsSb/Al0.7InAsSb digital alloy n-barrier-n (nBn) photodetectors that operate in the 2-μm wavelength window. The AlxIn1-xAsySb1-y digital alloy material system exhibits near-zero valence-band offset, which is beneficial for nBn photodetectors. At 300 K these Al0.3InAsSb/Al0.7InAsSb nBn photodetectors have achieved specific detectivities of 1.7 × 10 10 and 3.0 × 10 10 Jones under 2-μm and 1.8-μm illumination, respectively. The dark current density at -0.5 V bias decreases from 3.1 × 10 -3 A/cm 2 at 300 K to 1.6 × 10 -10 A/cm 2 at 120 K, where the dominant dark current component is tunneling. The area-dependence of key performance parameters show that for mesa diameter ≤ 250 μm, surface defects assume a dominant role in the total noise.

Composites or composite materials are engineered materials that consist of two or more constituent materials with wide discrepancies in their physical, chemical, and mechanical properties. The characteristic properties of these composite are as a result of the individual properties of their constituent parts and their respective volume fractions and arrangements in the material system. Depending on the intended application, composites can be designed to satisfy specific geometrical, structural, mechanical, chemical, and sometimes aesthetic requirements. Areas of application of these synthetic materials includes construction such as in buildings and bridges, automotive industry such as in car bodies, aeronautic, naval (e.g., ships and boats), and in the biomedical fields. Although metallic, polymeric and ceramic biomaterials have been in use for medical treatments such as tissue repairs and replacements for decades, composites are just coming to light. Therefore, the main purpose of this paper is to introduce composite materials and discuss their current and potential use in the biomedical field.

Achieving controls on the self-assembly of cationic and block copolymer micelles has significant implications for advancing novel material systems for energy, environmental, and biological applicat...

Self-assembly exists widely in natural living system and artificial synthetic material system. Administration of self-assemblies of artificial architectures in living cells can be used to explore the molecular physicochemical fundamentals and operating mechanisms of living system, and consequently promote the development of biomedicine. In order to mimic naturally occurring self-assemblies and realize controllable functions, great efforts have been devoted to constructing dynamic assembly of artificial architectures in living cells by responding to intracellular specific stimuli, which can be used to regulate morphology, behaviors and fate of living cells. This review highlights the recent progress on artificial self-assembly in living cells. The molecular fundamentals and characteristics of intracellular environment that can induce the self-assembly of artificial architectures are introduced, and the representative work on dynamic artificial self-assembly in living cells is sketched chronologically. Moreover, intracellular stimuli-mediated pathways of artificial assembly in living cells are categorized, biological effects caused by intracellular self-assembly are summarized, and biomedical applications focusing on therapy and imaging are described. In the end, the perspective and challenges of artificial self-assembly in living cells are fully discussed. It is believed that the grand advances on artificial self-assembly in living cells will contribute to elaborate the molecular mechanisms in cells, and further promote the biological and medical-related applications in the future.

Metallic transition-metal dichalcogenides (TMDs) are rich material systems in which the interplay between strong electron–electron and electron–phonon interactions often results in a variety of col...

The magnetic refrigeration (MR) utilizing magnetocaloric effect (MCE) has been recognized as an environmentally friendly and energy efficiency technology. Here we presented the magnetic properties and MCE in Pr-doped La1-xPrxFe12B6 (x=0.05-0.2) itinerant-electron metamagnetic (IEM) compounds. A small amount of Pr doping La site can greatly improve the peak values in the magnetic entropy change ΔSM(T) curves, especially under relatively low magnetic field changes (ΔH). Additionally, the peak temperature increases gradually and the magnetic hysteresis reduces gradually with increasing x. The observed MCE in present La1-xPrxFe12B6 compounds is related to its field-induced first-ordered IEM transition. The peak values of ΔSM for La1-xPrxFe12B6 compounds reach 13.4, 15.4, 12.5 and 13.0 J/(kg K) at TC ~58, 68, 72 and 89 K for x=0.05, 0.10, 0.15 and 0.2 under ΔH of 0-7 T, respectively. The corresponding relative cooling power values are 462.3, 480.7, 372.4 and 375.7 J/kg. The present La1-xPrxFe12B6 compounds could be good candidates for active MR application if the magnetic and thermal hysteresis can be further reduced. The present work indicates that the LaFe12B6-based material system could also exhibit promising magnetocaloric performances.

Synthesis of materials with desired structures, e.g., metal-organic frameworks (MOFs), involves optimization of highly complex chemical and reaction spaces due to multiple choices of chemical elements and reaction parameters/routes. Traditionally, realizing such an aim requires rapid screening of these nonlinear spaces by experimental conduction with human intuition, which is quite inefficient and may cause errors or bias. In this work, we report a platform that integrates a synthesis robot with the Bayesian optimization (BO) algorithm to accelerate the synthesis of MOFs. This robotic platform consists of a direct laser writing apparatus, precursor injecting and Joule-heating components. It can automate the MOFs synthesis upon fed reaction parameters that are recommended by the BO algorithm. Without any prior knowledge, this integrated platform continuously improves the crystallinity of ZIF-67, a demo MOF employed in this study, as the number of operation iterations increases. This work represents a methodology enabled by a data-driven synthesis robot, which achieves the goal of material synthesis with targeted structures, thus greatly shortening the reaction time and reducing energy consumption. It can be easily generalized to other material systems, thus paving a new route to the autonomous discovery of a variety of materials in a cost-effective way in the future.

Research into organic light emitters employing multiple resonance-induced thermally activated delayed fluorescence (MR-TADF) materials is presently attracting a great deal of attention due to the potential for efficient deep-blue emission. However, the origins and mechanisms of successful TADF are unclear, as many MR-TADF materials do not show TADF behaviour in solution, but only as particular pure solids. Here, an investigation into a well-known MR-TADF material, DABNA-1, together with other new MR materials (9H-quinolino[3,2,1-kl]phenothiazin-9-one (QPO) and 9H-quinolino-[3,2,1-kl]-phenothiazin-9-one 5,5-dioxide (QP3O)), yields new insights regarding the origin of TADF. Although a material system may support the concept of MR, inefficiency in both forward and reverse intersystem crossings forbids TADF unless a suitable host material allows an exciplex-like host–emitter interaction that boosts TADF. This boosted-TADF mechanism can be generalized to any fluorescence dye that lacks TADF in the photoluminescence measurement but has a thermally accessible S1–T1 energy gap, opening the way to high-performance organic light-emitting diodes. This study reveals the importance of host–guest interactions for effective multiple-resonance thermally activated delayed fluorescence in organic light emitters.

We simulate transport for proposed low excess-noise avalanche photodiode InAlAs/InAsSb type-II superlattice materials to evaluate their impact ionization coefficients; a key metric in determining avalanche photodiode performance. The ensemble Monte Carlo method is utilized to develop a stochastic transport kernel suitable for superlattice transport in the static field approximation. The electronic band structure and impact ionization rates are computed from a 14-band superlattice envelope function $$\varvec{K}\cdot \varvec{p}$$ formalism. We reveal that band engineering through superlattice design can be utilized to enhance the electron-to-hole impact ionization ratio in the InAlAs/InAsSb superlattice material system.

Cesium copper (I) halides, as a lead-free halide material system, have shown great potential in optoelectronic devices due to their environmental friendliness, high quantum efficiency, and extraord...

Liquid crystalline elastomers (LCEs) are crosslinked polymer networks that combine the elastic properties of rubber with the anisotropic properties of liquid crystals. Multifunctionality and responsivity can be programmed into LCEs by patterning their local orientation, which is difficult to achieve in other monolithic material systems. Advances in the synthesis and alignment of LCEs have paved the way for their functional integration in robotics, optics, consumer products, energy and healthcare devices. In this Review, we discuss recent advances in materials chemistry and processing that have contributed to the resurgence in LCE research. We examine the mechanical response of LCEs to stimuli and survey approaches for mechanical alignment, surface-enforced alignment, field-induced alignment and rheological alignment. The Review concludes with an over-the-horizon outlook discussing current challenges and emerging research opportunities. Liquid crystalline elastomers are stimuli-responsive polymeric materials whose mechanical properties can be programmed by patterning their local orientation, making them promising candidates to serve as low-density actuators and functional elements in various applications. This Review discusses the synthesis and processing of liquid crystalline elastomers, with a focus on alignment methods and potential applications.

Copper (Cu) and its alloys are prospective materials in fighting covid-19 virus and several microbial pandemics, due to its excellent antiviral as well as antimicrobial properties. Even though many studies have proved that copper and its alloys exhibit antiviral properties, this research arena requires further research attention. Several studies conducted on copper and its alloys have proven that copper-based alloys possess excellent potential in controlling the spread of infectious diseases. Moreover, recent studies indicate that these alloys can effectively inactivate the covid-19 virus. In view of this, the present article reviews the importance of copper and its alloys in reducing the spread and infection of covid-19, which is a global pandemic. The electronic databases such as ScienceDirect, Web of Science and PubMed were searched for identifying relevant studies in the present review article. The review starts with a brief description on the history of copper usage in medicine followed by the effect of copper content in human body and antiviral mechanisms of copper against covid-19. The subsequent sections describe the distinctive copper based material systems such as alloys, nanomaterials and coating technologies in combating the spread of covid-19. Overall, copper based materials can be propitiously used as part of preventive and therapeutic strategies in the fight against covid-19 virus.

From the Conant-Ashby theorem about the "good regulator" is possible to derive a corollary about the origin of life (OOL). This corollary introduces the concept of "good constructor." Thenit is shown as nature, seen as a material system ruled by the laws of physics, cannot be a "good constructor" of the basic machinery necessary for a living cell. As a consequence OOL needs intelligent design.

The establishment of superlow friction in moist air is very important for the engineering application of hydrogenated diamond-like carbon (H-DLC) films. Nevertheless, water molecules in the surrounding atmosphere always result in the failure of the near-frictionless state. This work aims to explore the effects of water molecules in the environment and the material of the counterparts on the tribological performance of a composite structure prepared by depositing MoS2 on a H-DLC film. The results indicated that the existence of water molecules in the atmosphere is beneficial for achieving stable superlubricity for the material system because it helps retain the in-situ formed MoS2 transfer film on the counterpart. In the presence of water molecules, the wear interface was replaced by a robust and incommensurate MoS2 tribolayer/H-DLC sliding interface, which was responsible for the superlow friction achieved in this work. The results also revealed that the ZrO2 counterpart was capable of retaining the as-formed MoS2 transfer film and establishing long-lasting superlow friction even in dry air. The mechanisms behind this phenomenon are also discussed in this paper.

Intralaminar cracking in relatively thick 90-plies of [[Formula: see text]]s laminates is analyzed using experimental data for two Glass fiber/Epoxy (GF/EP) material systems. Weibull parameters for transverse failure stress of the 90-ply are obtained from experimental intralaminar crack density versus applied strain data, showing that a reliable analysis requires sufficient amount of data in so called noninteractive crack density region. Monte Carlo simulations of cracking were performed using stress distribution between two cracks calculated using two models: Hashin’s model and a novel model that ensures that the average stress is exactly the same as in FEM solution. Due to its features, the Hashin’s model predicts too low intralaminar crack density (it predicts too strong interaction between cracks). The results emphasize the importance of having a proper stress distribution model when performing Monte Carlo simulations. Simulations were used not only to simulate intralaminar cracking in high and very low crack density regions but also for improving the procedure of Weibull parameter determination.

In this article, we report on the effective transconductance ( ${g}_{m}$ ) and gain linearity improvement of submicrometer gate AlN-barrier-based transistors using GaN/InGaN coupling-channel structures. The fabricated AlN/GaN/InGaN coupling-channel high electron mobility transistor (CC-HEMT) showed flat ${g}_{m}$ profile, greatly reduced ${g}_{m}$ derivatives, and constant dynamic source resistance compared with an AlN/GaN HEMT using the same fabrication process. The highest extrinsic current gain cutoff frequency ( ${f}_{T}$ ) of 55 GHz and the maximum oscillation frequency ( ${f}_{\text {max}}$ ) of 80 GHz were obtained for 0.15- $\mu \text{m}$ gate-length transistors, both of which remain constant values across wide input voltage ( ${V}_{\text {GS}}$ ) of 4 V. Moreover, a significant theoretical OIP3 value boost by 7.1 dB has been observed using the CC-HEMT as compared to the AlN/GaN HEMT. The superior linearity performance of the CC-HEMT can be attributed to the strong channel-to-channel coupling effect. The drain bias-dependence of ${g}_{m}$ , ${f}_{T}$ , and ${f}_{\text {max}}$ versus ${V}_{\text {GS}}$ profiles illustrate that the linearity characteristics of the CC-HEMT greatly improve with an increase in ${V}_{\text {DS}}$ . These results demonstrate the AlN/GaN/InGaN material system as a viable platform for high frequency requiring high-linearity applications.

Photocatalysis utilizes solar energy to produce clean fuels such as hydrogen or generate highly reactive species to subsequently break the organic pollutants into clean end products. Direct Z-scheme heterostructured photocatalysts can overcome the fundamental shortcomings in conventional photocatalysts and thus enable this green technology in tackling the energy crisis and environmental problems at the same time. Various approaches and numerous materials have been attempted in the hope of achieving high efficiency and broad effectiveness for practical applications. This work intends to provide a comprehensive and timely review on direct Z-scheme photocatalysts from the material’s point of view. The formation mechanisms based on the driving forces of the charge transfer are firstly discussed to guide the material design. Three mechanisms, namely internal electric field, interfacial defect-induced charge transfer, and facet-induced charge transfer, are identified and summarized. Various material systems are then extensively discussed and compared according to their applications, followed by the emerging material modification strategies for performance improvement. Lastly, the review provides the perspectives for future development. It is expected that the insights of this up-to-date review could guide the material design and performance improvement of the direct Z-scheme systems to achieve their maximum potentials.

Hydrogen is identified as the most promising zero-carbon fuel of the future. Naturally, in this regard, the hydrogen evolution reaction (HER), being a first critical step of the hydrogen technology and economy, attracts much attention. Conventionally, noble metals have been used as the electrocatalyst for HER, which in part holds back the hydrogen technology to become a large scale and heavily distributed energy technology. This has encouraged scientists to study cost-effective strategies for HER. Transition metal disulfides, being a low-cost material system with a great degree of engineering versatility, have recently emerged as a potential candidate that can significantly promote hydrogen evolution. Several studies have demonstrated that the control and manipulation of the structure and morphology of these materials can improve their proton reduction performance. This review covers many of the decisive factors and strategies to advance transition metal sulfides for HER applications.

In this study, S0.4Co4Sb11.2Te0.8 skutterudites with a highly porous structure inside grains are prepared by a one-step hot-pressing (OS-HP) method. The effect of the pressure relief treatment at the heating stage on the micro-morphology and thermoelectric properties of materials is investigated. When the temperature corresponding to the pressure relief treatment is less than 723 K, the grain size dramatically increases from ∼1 to ∼50 μm, and a large number of pores are distributed inside these large grains. Compared with those samples prepared by the conventional method, the thermal conductivity of samples prepared by the pressure relief treatment is significantly reduced due to the high porosity. The ZT values of samples prepared by the pressure relief treatment are greater than 1.6 at 825 K. This newly developed OS-HP method can be employed for the rapid fabrication of highly porous structured skutterudites with low-melting-point compositions as well as of other material systems.

This study was conducted to determine the degree of difficulty in learning mathematics in grade X students with the population in this study is 359 students grade X and the number of study samples is 72 students were taken with cluster sampling techniques. Data collection techniques in this study used a essay test and unstructured interview questions for 10 students. The instrument of this study are in the form of mathematical essay questions that are closed to the material system of linear equations in two variables for 4 problems. The data obtained were analyzed by fit student answers and key answers in learning difficultiy analysis guide. The results of this study indicate that students of class X in the academic year 2019/2020 had the most difficulty learning principle in the amount of 21.90% which is included in the low category level. While students who had difficulty learning concepts and operations are 13.90% and 12.34% respectively included in the very low category level.

This article proposes a new approach for mapping material flows through the economy referred to as economy‐wide material system analysis (EW‐MSA). EW‐MSA monitors material flows along production chains, connects manufacturing and use of various products with related emission flows, and shows how waste is recycled. The quantification of material flows in EW‐MSA is carried out by unambiguously defined EW‐MSA indicators. The data on EW‐MSA indicators are organized in an EW‐MSA database while the results of EW‐MSA can be clearly presented with Sankey flow charts. The proposed method was tested using the Czech Republic as a case study. It shows that the Czech Republic is an open economy, as more manufactured products are exported than used domestically. The total physical stock of materials in the economy is continuously growing and only about 7% of total material input into manufacturing is composed of secondary materials. Manufacturing of motor vehicles and transport equipment is highly dependent on imported materials and a significant amount of waste from motor vehicles’ manufacture and use is exported instead of being recycled and returned to the manufacturing process. Further development and use of EW‐MSA should go hand in hand with the development of needed data sources: Only a fraction of data was directly accessible in the official statistics while the rest had to be modeled with the use of other data and various coefficients. This burdened the results with some uncertainties.

Discrete dislocation structures and their evolution are known to control the mechanical properties of metal samples. However, the lack of computationally efficient and statistically rigorous descriptors for such defect systems has hindered the development and adoption of rational protocols for the optimal design of these material systems. This study presents a framework for the rigorous statistical quantification and low-dimensional representation of dislocation structures using the formalism of 2-point statistics (also called 2-point spatial correlations) along with principal component analysis. The usefulness of this basic framework for comparing and observing dislocation structures is exemplified and discussed with suitable examples.

Near-infrared persistent phosphors (NIR-PPs) are an emerging category of luminescent materials that can continuously emit NIR luminescence with super-long decay time of minutes, hours, or even days after the excitation ceases. Their unique excitation-free long-lasting afterglow, together with the NIR emission, has not only attracted wide research interests in the areas of photochemistry, photophysics, spectroscopy, and materials science, but also stimulated advanced applications in biosensing, bioimaging, biomedicine, and therapy in the past decade. Beyond these bio-related applications, the active research field triggers a number of novel applications recently. In this review, a brief outline of NIR-PPs including the luminescence mechanism, main material systems, and how they were applied into various fields was depicted. Particular emphasis was put on the emerging applications outside the field of biology. Future perspectives in this exploration research area were also presented. We hope this review can help researchers grab the latest information in the fast-growing field of NIR-PPs.

FRP material properties offer unique opportunities for architecture, but their mould-based standard forming processes stand in contrast to contemporary practices, aiming for variation and surface a...