Marked-LIEO: Visual Marker-Aided LiDAR/IMU/Encoder Integrated Odometry.

In this paper, we propose a visual marker-aided LiDAR/IMU/encoder integrated odometry, Marked-LIEO, to achieve pose estimation of mobile robots in an indoor long corridor environment. In the first stage, we design the pre-integration model of encoder and IMU respectively to realize the pose estimation combined with the pose estimation from the second stage providing prediction for the LiDAR odometry. In the second stage, we design low-frequency visual marker odometry, which is optimized jointly with LiDAR odometry to obtain the final pose estimation. In view of the wheel slipping and LiDAR degradation problems, we design an algorithm that can make the optimization weight of encoder odometry and LiDAR odometry adjust adaptively according to yaw angle and LiDAR degradation distance respectively. Finally, we realize the multi-sensor fusion localization through joint optimization of an encoder, IMU, LiDAR, and camera measurement information. Aiming at the problems of GNSS information loss and LiDAR degradation in indoor corridor environment, this method introduces the state prediction information of encoder and IMU and the absolute observation information of visual marker to achieve the accurate pose of indoor corridor environment, which has been verified by experiments in Gazebo simulation environment and real environment.

Crystal Facet Effects on Nanomagnetism of Co3O4.

The magnetic performance of nanomaterials depends on size, shape, and surface of the nanocrystals. Here, the exposed crystal planes of Co3O4 nanocrystals were analyzed to research the dependence of magnetic properties on the configuration environment of the ions exposed on different surfaces. The Co3O4 nanocrystals with exposed (1 0 0), (1 1 0), (1 1 1), and (1 1 2) planes were synthesized using a hydrothermal method in the shapes of nanocube, nanorod, hexagonal nanoplatelet, and nanolaminar, respectively. Ferromagnetic performance was detected in the (1 0 0) and (1 1 1) plane-exposed samples. First-principles calculation results indicate that unlike the nonmagnetic nature in the bulk, the Co3+ ions exposed on or close to the surface possess sizable magnetic moments because of the variation of coordination numbers and lattice distortion, which is responsible for the ferromagnetic-like behavior. The (1 1 0)-exposed sample keeps the natural antiferromagnetic behavior of bulk Co3O4 because either the surface Co3+ ions have no magnetic moments or their moments are in antiferromagnetic coupling. The (1 1 2)-exposed sample also displays antiferromagnetism because the interaction distances between the magnetized Co3+ ions are too long to form effective ferromagnetic coupling.

Solvothermal Synthesis of a Hollow Micro-Sphere LiFePO4/C Composite with a Porous Interior Structure as a Cathode Material for Lithium Ion Batteries.

To overcome the low lithium ion diffusion and slow electron transfer, a hollow micro sphere LiFePO4/C cathode material with a porous interior structure was synthesized via a solvothermal method by using ethylene glycol (EG) as the solvent medium and cetyltrimethylammonium bromide (CTAB) as the surfactant. In this strategy, the EG solvent inhibits the growth of the crystals and the CTAB surfactant boots the self-assembly of the primary nanoparticles to form hollow spheres. The resultant carbon-coat LiFePO4/C hollow micro-spheres have a ~300 nm thick shell/wall consisting of aggregated nanoparticles and a porous interior. When used as materials for lithium-ion batteries, the hollow micro spherical LiFePO4/C composite exhibits superior discharge capacity (163 mAh g-1 at 0.1 C), good high-rate discharge capacity (118 mAh g-1 at 10 C), and fine cycling stability (99.2% after 200 cycles at 0.1 C). The good electrochemical performances are attributed to a high rate of ionic/electronic conduction and the high structural stability arising from the nanosized primary particles and the micro-sized hollow spherical structure.

Nanoengineering to Achieve High Sodium Storage: A Case Study of Carbon Coated Hierarchical Nanoporous TiO2 Microfibers.

Nanoengineering of electrode materials can directly facilitate sodium ion accessibility and transport, thus enhancing electrochemical performance in sodium ion batteries. Here, highly sodium-accessible carbon coated nanoporous TiO2 microfibers have been synthesised via the facile electrospinning technique which can deliver an enhanced capacity of ≈167 mAh g-1 after 450 cycles at current density of 50 mA g-1 and retain a capacity of ≈71 mAh g-1 at the high current rate of 1 A g-1. With the benefits of their porous structure, thin TiO2 inner walls, and the introduction of conductive carbon, the nanoporous TiO2/C microfibers exhibit high ion accessibility, fast Na ion transport, and fast electron transport, thereby leading to the excellent Na-storage properties presented here. Nanostructuring is proven to be a fruitful strategy that can alleviate the reliance on materials' intrinsic nature; and the electrospinning technique is versatile and cost-effective for the fabrication of such an effective nanoporous microfiber structure.

Fabricating Co doped ZnO nanocrystallines by hydrothermal method with high pulsed magnetic field.

Co-doped ZnO nanocrystallines were fabricated by hydrothermal method with high pulsed magnetic field. As a new preparation method, more refined grains and diluted magnetic semiconductors (DMSs) with better performance could be obtained by the hydrothermal synthesis process under pulsed magnetic field. The samples were tested by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Vibrating Sample Magnetometer (VSM) and Raman scattering spectrum. The results show that the sample prepared under pulsed magnetic field has wurtzite structure with tiny crystal lattices changes. Doping Co ions into ZnO crystal lattice is also improved. Curie temperature of 2% Co doped ZnO nanocrystallines synthesized with 4T pulsed magnetic field is higher than that for without magnetic field process, and very close to the room temperature.

Construction of uric acid biosensor based on biomimetic titanate nanotubes.

A uric acid biosensor has been fabricated through the immobilization of uricase on glassy carbon electrode modified by biomimetic titanate nanotubes of high specific surface area synthesized by hydrothermal decomposition. The so-constructed biosensor presents a high affinity to uric acid with a small apparent Michaelis-Menten constant of only 0.66 mM. The biosensor exhibits fairly good electrochemical properties such as the high sensitivity of 184.3 microAcm(-2)mM(-1), the fast response of less than 2 s, as well as the wide linear range from 1 microM to 5 mM. These performances indicate that titanate nanotubes could provide a favorable microenvironment for uricase immobilization, stabilize its biological activity, and function as an efficient electron conducting tunnel to facilitate the electron transfer. This suggests an important potential of titanate nanotubes in uric acid biosensors.

Field emission and optical properties of ZnO nanowires grown directly on conducting brass substrates.

Large-area and uniform ZnO nanowires have been produced directly on a conducting brass substrate by annealing a Cu0.66Zn0.34 foil under a mixture of argon and oxygen. The morphology, structure, and composition of the ZnO nanowires are characterized by X-ray diffraction, electron microscopy, energy-dispersive X-ray spectrometry, and X-ray photoelectron spectroscopy. The ZnO nanowires with diameters of about 40-70 nm and lengths up to micrometers grow preferentially along the [001] direction. Since the Cu0.66Zn0.34 foil serves as both the Zn source and substrate, the synthesis and assembly of the ZnO nanowires on a conducting substrate is accomplished in one step, and good intrinsic adhesion and robust electrical contact between the ZnO nanowires and conducting substrate are realized. This ZnO configuration forms an ideal field emitter and good field emission properties are corroborated in this study. Photoluminescence studies indicate that these ZnO nanowires have good optical quality exhibiting strong ultraviolet (UV) emission at 383 nm and a weak visible emission band centered around 485 nm at room temperature. The good field emission and optical properties suggest that ZnO nanowires fabricated by this method have promising applications in nano-optoelectronic and field emission devices.

Synthesis of hierarchical tree-like and jellyfish-like silicon oxide nanostructures.

Hierarchical tree-like and jellyfish-like SiOx nanostructures have been synthesized by annealing a mixture of carbon coated Ni nanoparticles (Ni@C) and SiO2 powers under argon atmosphere at 1400 degrees C. The synthesized products were characterized by electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The tree-like SiOx nanostructures consisting of the trunks and many branches and subbranches with diminishing diameters have been observed for the first time. The diameters of the trunks are about 150-1000 nm, and the branches become more slender for each branching, ultimately to 20-40 nm in diameter for the ends. The jellyfish-like SiOx nanostructures are constructed by the catalyst heads with sizes of about 1-10 microm and many connected quasi-aligned SiOx nanowires with diameters about 20-40 nm. The Ni species of the Ni@C nanoparticles acts as the catalyst and the surface carbon as the reducing agent for carbothermal reduction of SiO2. The experimental results suggest that the formation of different SiOx nanostructures mainly depend on the dimensions of the congregated Ni catalyst droplets during the reaction process and the growth mechanism is reasonably discussed.

Synthesis and field emission characterization of titanium nitride nanowires.

Single crystalline titanium nitride nanowires have been successfully synthesized through a chloride-assisted carbon thermal reduction method using the active carbon, TiO2 and NaCl powders as precursors and cobalt nanoparticles as catalyst. The products were characterized by X-ray diffraction, electron microscopy, and energy-dispersive X-ray spectroscopy. The TiN nanowires possess a cubic structure with typical diameter of 20-60 nm and length up to microns. The field emission property of the TiN nanowires has been characterized for the first time, which follows the conventional Fowler-Nordheim behavior and shows the low turn-on field of 7.1 V microm-1 and good emission stability, indicating the potential applications. The formation mechanism of the TiN nanowires has also been discussed.

Chemical functionalization of magnetic carbon-encapsulated nanoparticles based on acid oxidation.

Carbon-encapsulated nickel nanoparticles were used as the representative magnetic carbon-encapsulated nanoparticles for chemical functionalization. After oxidation with the mixed acid of H2SO4/HNO3 under a moderate ultrasonic bath, carboxylic acid groups (-COOH) were effectively generated on the fullerene-like carbon shells, which in turn were utilized to covalently link octadecylamine through an amide reaction. The whole chemical process is well characterized by many methods such as Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetry-differential scanning calorimetry, transmission electron microscopy, and so on, and the self-consistent experimental results were obtained. The results suggested that the magnetic nanoparticles could be well protected, while their magnetic properties could be utilized to guide the transfer of the grafted functional species on the particle surface. This provides many possibilities for potential applications in chemical and biochemical fields.

Fabrication, characterization and field emission properties of large-scale uniform ZnO nanotube arrays.

Large-scale well-aligned ZnO nanotubes with outer diameters of 100-300 nm and lengths of tens of micrometres have been prepared by a template-based chemical vapour deposition method. The photoluminescence spectrum of the ZnO nanotube arrays consists of a strong violet band at 414 nm, a blue band at 462 nm and a weak shoulder peak at around 480 nm. The field emission of the ZnO nanotube arrays shows a turn-on field of about 7.3 V microm(-1) at a current density of 0.1 microA cm(-2) and emission current density up to 1.3 mA cm(-2) at a bias field of 11.8 V microm(-1).

Synthesis of single-crystalline alpha-Si(3)N(4) nanobelts by extended vapour-liquid-solid growth.

A simple chemical method for the production of single-crystalline alpha-Si(3)N(4) nanobelts has been developed, consisting of nitridation of a high-Si-content Fe-Si 'catalyst' by ammonia at 1300 degrees C. The as-synthesized product was characterized by means of x-ray diffraction, electron microscopy and energy-dispersive x-ray spectroscopy. The alpha-Si(3)N(4) nanobelts have widths of 60-120 nm, thicknesses of 10-30 nm and lengths up to microns. Four intense green-blue luminescence bands at 398 nm (3.12 eV), 434 nm (2.86 eV), 492 nm (2.52 eV) and 540 nm (2.30 eV) were observed and analysed for the product, which indicates the potential applications in optoelectronics. The growth mechanism has also been speculated upon. The potential technological importance of the product, the simplicity of the preparation procedure, as well as the cheap commercial precursor of Fe-Si alloy particles makes this study both scientifically and technologically interesting.