In confined multi-obstacle environments, generating feasible paths for continuum robots is challenging due to the need to avoid obstacles while considering the kinematic limitations of the robot. This paper deals with the path-planning algorithm for continuum robots in confined multi-obstacle environments to prevent their over-deformation. By modifying the tree expansion process of the Rapidly-exploring Random Tree Star (RRT*) algorithm, a path-planning algorithm called the continuum-RRT* algorithm herein is proposed to achieve fewer iterations and faster convergence as well as generating desired paths that adhere to the kinematic limitations of the continuum robots. Then path planning and path tracking are implemented on a tendon-driven four-section continuum robot to validate the effectiveness of the path-planning algorithm. The path-planning results show that the path generated by the algorithm indeed has fewer transitions, and the path generated by the algorithm is closer to the optimal path that satisfies the kinematic limitations of the continuum robot. Furthermore, path-tracking experiments validate the successful navigation of the continuum robot along the algorithm-generated path, exhibiting an error range of 2.51%–3.91%. This attests to the effectiveness of the proposed algorithm in meeting the navigation requirements of continuum robots.

As an important part of the manufacturing industry, redundant robots can undertake heavy and tough tasks, which human operators are difficult to sustain. Such onerous and repetitive industrial manipulations, that is, positioning and carrying, impose heavy burdens on the load bearing for redundancy robots’ joints. Under the circumstances of long-term and intense industrial operations, joints of redundant robots are conceivably to fall into functional failure, which may possibly cause abrupt joint lock or freeze at unknown time instants. Therefore, task accuracy by end-effectors tends to diminish considerably and gradually because of broken-down joints. In this paper, a sparsity-based method for fault-tolerant motion planning of redundant robots is provided for the first time. The developed fault-tolerant redundancy resolution approach is defined as L1-norm based optimization with immediate variables involved to avoid discontinuity in the dynamic solution process. Meanwhile, those potential faulty joint(s) can be located by the designed fault observer with the proposed fault-diagnosis algorithm. The proposed fault-tolerant motion planning method with fault diagnosis is dynamically optimized by resultant primal dual neural networks with provable convergence. Moreover, the sparsity of joint actuation by the proposed method can be enhanced by around 43.87% and 36.51%, respectively, for tracking circle and square paths. Simulation and experimental findings on a redundant robot (KUKA iiwa) prove the efficacy of the developed defect tolerant approach based on sparsity.

We divide the corrosion products on ancient bronzes into two categories, i.e., "inward growth" and “outward growth” corrosions. Several selected Chinese ancient bronzes with the "inward growth” corrosion are studied; and their chemical compositions, microstructures and morphologies are characterized systematically. According to the results, it is found that the “inward growth” corrosion can be further divided into three types, i.e., "noble patina", "noble-like patina" and "lamellar peeling patina". We propose that the growth mechanism of the “inward growth” corrosion is that the corrosion initiates at and develops along α-Cu phase. Furthermore, the effect of alloy Sn content on the “inward growth” corrosion is also studied.

In this study, a novel brick-like NiCo2O4 material was synthesized via a facile hydrothermal method. The as-prepared NiCo2O4 material possessed high porosity with the BET specific surface area of 58.33 m2/g, and its pore size distribution was in a range of 5-15 nm with a dominant pore diameter of 10.7 nm. The electrochemical performance of the NiCo2O4 was further investigated as anode material for lithium-ion battery. The NiCo2O4 anode possessed a high lithium storage capacity up to 2353.0 mAh/g at the current density of 100 mA/g. Even at the high rate of 1 A/g, a reversible capacity of ∼600 mAh/g was still retained, and an average discharge capacity of ∼1145 mAh/g could be recovered when the current density was reduced back to 150 mA/g. Due to the simple and cost-effective process, the NiCo2O4 bricks anode material shows great potential for further large-scale applications on the area of lithium-ion battery.

Developing metal-based composite coatings with improved mechanical properties and good corrosion resistance has been an attractive research topic in recent years. Graphene (Gr), as a new type of two-dimensional (2D) carbon nanomaterial with excellent physical, chemical and mechanical properties, can be used as a reinforcement to improve hardness, tensile strength, wear and corrosion resistance of metal-based composites. There have been substantial efforts focused on the fabrication of metal-Gr composite coatings via various approaches. Electro-deposition is an effective electrochemical method with wide range of advantages, such as a fast deposition rate, simple set-up with large scale production and relatively low cost. This overview covers the previous research and development studies on metal-Gr composite coatings using electro-deposition method and the resulting properties. In addition, recent work in this area which provides a developed process with industrial production perspective, is discussed.

In the past few years, our group worked on the area of transformation from the two-dimensional (2-D) nanocrystalline films to one-dimensional (1-D) nanomaterials by using thermal oxidation. In this paper, we overview the research work on the controllable growth processes, transformation phenomena, growth mechanisms and applications. In general, the preparation process includes the following steps: 1) prepare a pure metal nanocrystalline film via a pulse electro – deposition; 2) grow variant 1-D nanomaterials, such as carbon nanotubes (CNTs), carbon nanofibers (CNFs), and 1-D metal oxide nanoneedles involving ZnO, CuO and Fe3O4, etc. by using this film as catalyst. This process exhibits the following features: 1) the 1-D nanomaterials grow according to “base growth” model and no residual catalyst exists at the tip of the products; 2) the diameter of the 1-D nanomaterials can be controlled by controlling grain sizes of the 2-D films through adjusting pulse electro-deposition parameters; 3) it is more easily to get the 1-D nanomaterials with large area, uniform, vertical alignment and good shape on the substrates. We propose a “solid state based-up diffusion growth mechanism” for growth of the 1-D metal oxide nanoneedles, and “base growth model” for the 1-D carbon nanomaterials. The physical properties, such as Field emission and magnetics, of the 1-D metal oxide nanoneedles were studied, which showed desired values. In addition, we couple the ZnO nanoneedles with NiO, TiO2, graphene, Au nanoparticles, etc. for enhancing photocatalytic properties in the areas of environmental purification.

Ancient Chinese bronzes are precious cultural relics. Their surfaces are often severely damaged by dynamic changes in the external environment, both before and after they are unearthed. Therefore, scientific research has been required to preserve these treasures. In recent years, along with the development of modern science and technology, innovative instrumental analytical techniques have become indispensable tools to study corrosion phenomena as well as to evaluate post-excavation conservation techniques. In this paper, we present an overview of bronze corrosion processes in various environments, including analysis of the types of corrosion, mechanisms of formation and factors that influence bronze corrosion products. In addition, we compare the characteristics of corrosion products that have formed on archaeological sites, in tombs, and in museums. Lastly, we introduce some novel techniques for bronze protection, and we propose the focus for future research. Our expectation is that this review will provide a scientific basis for bronze preservation.

In order to enhance the photocatalytic efficiency of oxide semiconductors, variant processes have been proposed. The creation of the heterojunction composites has attracted considerable attentions and developed into an important research area for the high performance photocatalyst preparation. In this paper, we introduce the research progress on heterojunction composites which were prepared via a novel physical route with relatively high temperature treatments. It is hope that this mini-review can inspire research interest in the realm of heterojunction synthesis based on the thermal diffusion mechanism.

In addition to the piezoelectric nanogenerators and triboelectric nanogenerators, recently, the graphene-based nanogenerator has been widely concerned because of its simple assembly, flexibility and high structural stability. There are many interesting effects in graphene applied for nanogenenrators including anion adsorption in electrolyte solution, ion channels in graphene sheets network and the strain (band engineering) effect, etc. In this paper, we focus explicitly on the experimental results, mechanisms and applications of the graphene-based nanogenerator, and introduce our recent research on the graphene-based nanogenerator based on "modulation of the graphene strain-energy band effect". This nanogenerator is expected to have potential applications in active sensors and sustainable power source.

ZnO/TiO2 heterojunction composite fibers were prepared via a physical route, i.e., first electrospinning titanium dioxide (TiO2) fibers, then pulse plating zinc (Zn) on the fibers, and at last thermal treating the fibers. The morphologies, phase structures, and photocatalytic property of the composite fibers were characterized by using field-emission gun scanning electron microscope, x-ray diffractometer, high-resolution transmission electron microscope, and ultraviolet–visible spectrophotometer. It was found that a full or partial lattice coherent heterojunction was formed between the TiO2 fibers and zinc oxide (ZnO) particles, due to thermal treatment at 400 °C, which simultaneously resulted in the phase transformations including Zn to ZnO and amorphous TiO2 to anatase TiO2. The experimental results demonstrated that the photocatalytic activity of the composite fibers was improved and exhibited a value more than two times higher than that of TiO2 fibers.

Instrumented nanoindentation technique is a powerful approach for accurately measuring mechanical properties of materials in micron or even nanoscale. In this article, the effect of tin (Sn) content upon mechanical properties of the α-phase in Cu–Sn alloys was studied by using an instrumented nanoindentation. The experimental results revealed that: (i) the hardness of the α-phase exhibited a linear relationship with Sn content (C) increasing, i.e., H = 0.0757C + 0.8916, when it was less than the maximum solid solubility (15.8 wt.%), which is in good agreement with the Friedel–Mott–Suzuki theory; (ii) the variation of Young’s modulus in a narrow range of 120–130 GPa is attributed to orientation variation of the α-phase in casting Cu–Sn dendrites.