Harbin University

This review summarizes recent progress in the design and fabrication of carbon materials for high volumetric performance supercapacitors.

The design and characterization of metal-organic complexes for optoelectronic applications is an active area of research. The metal-organic complex offers unique optical and electronic properties arising from the interplay between the inorganic metal and the organic ligand. The ability to modify chemical structure through control over metal-ligand interaction on a molecular level could directly impact the properties of the complex. When deposited in thin film form, this class of materials enable the fabrication of a wide variety of low-cost electronic and optoelectronic devices. These include light emitting diodes, solar cells, photodetectors, field-effect transistors as well as chemical and biological sensors. Here we present an overview of recent development in metal-organic complexes with controlled molecular structures and tunable properties. Advances in extending the control of molecular structures to solid materials for energy conversion and information technology applications will be highlighted.

A climax in the development of cost-effective and high-efficiency transition metal-based electrocatalysts has been witnessed recently for sustainable energy and related conversion technologies. In this regard, structure-activity relationships based on several descriptors have already been proposed to rationally design electrocatalysts. However, the dynamic reconstruction of the surface structures and compositions of catalysts during electrocatalytic water oxidation, especially during the anodic oxygen evolution reaction (OER), complicate the streamlined prediction of the catalytic activity. With the achievements in operando and in situ techniques, it has been found that electrocatalysts undergo surface reconstruction to form the actual active species in situ accompanied with an increase in their oxidation state during OER in alkaline solution. Accordingly, a thorough understanding of the surface reconstruction process plays a critical role in establishing unambiguous structure-composition-property relationships in pursuit of high-efficiency electrocatalysts. However, several issues still need to be explored before high electrocatalytic activities can be realized, as follows: (1) the identification of initiators and pathways for surface reconstruction, (2) establishing the relationships between structure, composition, and electrocatalytic activity, and (3) the rational manipulation of in situ catalyst surface reconstruction. In this review, the recent progress in the surface reconstruction of transition metal-based OER catalysts including oxides, non-oxides, hydroxides and alloys is summarized, emphasizing the fundamental understanding of reconstruction behavior from the original precatalysts to the actual catalysts based on operando analysis and theoretical calculations. The state-of-the-art strategies to tailor the surface reconstruction such as substituting/doping with metals, introducing anions, incorporating oxygen vacancies, tuning morphologies and exploiting plasmonic/thermal/photothermal effects are then introduced. Notably, comprehensive operando/in situ characterization together with computational calculations are responsible for unveiling the improvement mechanism for OER. By delivering the progress, strategies, insights, techniques, and perspectives, this review will provide a comprehensive understanding of the surface reconstruction in transition metal-based OER catalysts and future guidelines for their rational development.

Trifluorophenyl-functionalized multi-walled-carbon-nanotube/poly(vinylidene fluoride) (TFP-MWNT/PVDF) nanocomposites are fabricated by employing a wet-chemistry route. The modified MWNTs are observed to form a well-dispersed, structurally random nanophase within the polymer matrix (see figure). The TFP-MWNT/PVDF nanocomposite exhibits enhanced dielectric permittivity when the content of TFP-MWNT is close to the percolation threshold.

Bone tissue engineering has been continuously developing since the concept of "tissue engineering" has been proposed. Biomaterials that are used as the basic material for the fabrication of scaffolds play a vital role in bone tissue engineering. This paper first introduces a strategy for literature search. Then, it describes the structure, mechanical properties and materials of natural bone and the strategies of bone tissue engineering. Particularly, it focuses on the current knowledge about biomaterials used in the fabrication of bone tissue engineering scaffolds, which includes the history, types, properties and applications of biomaterials. The effects of additives such as signaling molecules, stem cells, and functional materials on the performance of the scaffolds are also discussed.

Nanocellulose from various kinds of sources and nanocellulose-derived materials have been developed for electrochemical energy storage, including supercapacitors, lithium-ion batteries, lithium–sulfur batteries, and sodium-ion batteries.

A comprehensive review on designs and mechanisms of semiconducting metal oxides with various nanostructures for room-temperature gas sensor applications.

Asymmetric supercapacitors with high energy density are fabricated using a self‐assembled reduced graphene oxide (RGO)/MnO 2 (GrMnO 2 ) composite as a positive electrode and a RGO/MoO 3 (GrMoO 3 ) composite as a negative electrode in safe aqueous Na 2 SO 4 electrolyte. The operation voltage is maximized by choosing two metal oxides with the largest work function difference. Because of the synergistic effects of highly conductive graphene and highly pseudocapacitive metal oxides, the hybrid nanostructure electrodes exhibit better charge transport and cycling stability. The operation voltage is expanded to 2.0 V in spite of the use of aqueous electrolyte, revealing a high energy density of 42.6 Wh kg −1 at a power density of 276 W kg −1 and a maximum specific capacitance of 307 F g −1 , consequently giving rise to an excellent Ragone plot. In addition, the GrMnO 2 //GrMoO 3 supercapacitor exhibits improved capacitance with cycling up to 1000 cycles, which is explained by the development of micropore structures during the repetition of ion transfer. This strategy for the choice of metal oxides provides a promising route for next‐generation supercapacitors with high energy and high power densities.

A novel MOF derivation method is used to prepare Fe/C nanocubes, which are constructed by a cubic framework of amorphous carbon decorated uniformly by Fe@graphitic carbon nanoparticles for microwave absorption.

Metal–organic frameworks (MOFs) have obtained increasing attention as a kind of novel electrode material for energy storage devices.

With the aid of DFT calculation, deep eutectic solvents can be designed more powerful for the pretreatment of lignocellulose and the production of biochemicals.

This review highlights breakthroughs in the past decade in the synthesis and the modification of both the chemistry and morphology of Li₄Ti₅O₁₂.

Biodegradable metals have attracted considerable attentions in recent years. Besides the early launched biodegradable Mg and Fe metals, Zn, an essential element with osteogenic potential of human body, is regarded and studied as a new kind of potential biodegradable metal quite recently. Unfortunately, pure Zn is soft, brittle and has low mechanical strength in the practice, which needs further improvement in order to meet the clinical requirements. On the other hand, the widely used industrial Zn-based alloys usually contain biotoxic elements (for instance, ZA series contain toxic Al elements up to 40 wt.%), which subsequently bring up biosafety concerns. In the present work, novel Zn-1X binary alloys, with the addition of nutrition elements Mg, Ca and Sr were designed (cast, rolled and extruded Zn-1Mg, Zn-1Ca and Zn-1Sr). Their microstructure and mechanical property, degradation and in vitro and in vivo biocompatibility were studied systematically. The results demonstrated that the Zn-1X (Mg, Ca and Sr) alloys have profoundly modified the mechanical properties and biocompatibility of pure Zn. Zn-1X (Mg, Ca and Sr) alloys showed great potential for use in a new generation of biodegradable implants, opening up a new avenue in the area of biodegradable metals.

Corn husk, a renewable biomass, has been successfully explored as a low-cost crude carbon source to prepare advanced higher-value 3D HPCs by means of KOH pre-treatment and direct pyrolysis, the synthesis route is simple, self-templating and easy to scale-up for industrialization.

Hierarchical NiCo₂O₄tetragonal microtubes prepared by a self-supported chemical transformation process exhibit an excellent electrochemical performance.

Lithium-ion batteries, carbon anode, lithium plating, characterization techniques, sluggish intercalation kinetics.

Abstract Artificial intelligence education (AIEd) is defined in the field of education as the utilization of artificial intelligence. There are currently many AIEd‐driven applications in schools and universities. This paper applies an artificial intelligence module combined with the knowledge recommendation to the system and develops an online English teaching system in comparison with the common teaching auxiliary system. The method of English teaching is useful in investigating the potential internal connections between evaluation outcomes and various factors. This article develops deep learning‐assisted online intelligent English teaching system that utilizes to create a modern tool platform to help students improve their English language teaching efficiency in line with their mastery of knowledge and personality. The decision tree algorithm and neural networks have been used and to generate an English teaching assessment implementation model based on decision tree technologies. It provides valuable data from extensive information, summarizes rules and data, and helps teachers to improve their education and the English scores of students. This system reflects the thinking of the artificial intelligence expert system. Test application demonstrates that the system can help students improve their learning efficiency and will make learning content more relevant. Besides, the system provides an example model with similar methods and has a referential definition.

Smart self-healing micro/nanocontainers that heal cracks in the coating by releasing active compounds in response to external stimuli were reviewed.

Techniques emerging from the considerable research on cognitive aspects of survey methodology include various forms of probing and cognitive interviewing. These techniques are used to examine whether respondents' interpretations of self-report items are consistent with researchers' assumptions and intended meanings given the constructs the items are designed to measure. However, although informal procedures are common, such developments have not been systematically applied in educational research. We describe how information derived from the systematic application of cognitive pretesting can contribute to determining the validity—designated cognitive validity—of self-report items. Examples are presented from prominent motivation-related instruments that assess real-world instructional practices, mastery classroom goal structure, and student self-efficacy. The implications and pragmatics of adopting this approach are discussed.

Electrochemical processes that can be used for wastewater treatment and resource reclamation are reviewed with suggestions for future research directions.