矿用无人卡车国内外研究现状及关键技术

分析了国内外露天矿山用卡车无人驾驶技术发展现状,详细介绍了露天矿山卡车无人驾驶关键技术;通过分析对比前装线控和后装线控两种技术路线的优缺点以及超声波雷达、毫米波雷达、激光雷达、4D光场智能感知系统、红外传感器、视觉传感器等环境感知技术的优缺点;提出多传感器高度融合将是露天矿山卡车实现全天候环境感知的发展方向。通过分析对比惯性导航系统、GNSS差分定位技术、车联网定位技术、电子地图定位技术、视觉传感器等定位导航技术的差异,指出多定位技术融合是露天矿山无人驾驶卡车定位方式的必然选择。结合露天煤矿的生产实际,提出将现有的无人驾驶各种技术算法与露天矿山标准作业流程有机融合是实现卡车无人驾驶的必由之路。最后指出无人驾驶卡车应用5G技术是露天矿山安全生产的关键和核心,是无人驾驶的必备技术。     

Yellow resistant photosensitive resin for digital light processing 3D printing

Digital light processing (DLP) has been studied and developed in the field of three-dimensional (3D) printing in recent years due to its fast curing rate and high resolution. To reduce the cost and viscosity of the resin system, the aromatic polyurethane acrylates (PUAs) were used as oligomer. The matrix resin called PUH₂ consists of oligomers (PUA, bisphenol A polyoxyethylene ether dimethyl acrylate) and active diluents (hydroxyethyl acrylate, hydroxyethyl methacrylate). However, the photosensitive resin containing aromatic isocyanate groups was easily yellowed under ultraviolet light. In this article, we developed a resin for DLP 3D printing with yellowing resistance, excellent mechanical properties and high heat resistance. The optimal ratio of 3DP-PUH₂ resin was PUH₂/TPO/RYOJI-292/dye/nanosilica = 100/5/0.4/0.01/0.1, and its viscosity was 500 cp, which is suitable for DLP 3D printing. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48369.     

Fabrication and photocatalytic performance of one-dimensional Ag3PO4 sensitized SrTiO3 nanowire

The 1D Ag₃PO₄ sensitized SrTiO₃ nanowires are prepared by simple route of electrospinning-in situ deposition technique. The results of the thermogravimetry (TG), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive Spectrometer (EDS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV–Visible diffuse reflectance spectroscopy (UV–Vis) indicate that the Ag₃PO₄ nanoparticles has been deposited on the surface of the SrTiO₃ nanowires successfully. Experimental results showed that compared with pure SrTiO₃, the as-prepared 1D Ag₃PO₄ sensitized SrTiO₃ nanowires exhibit obvious enhancement of photocatalytic performance and stability. Especially, the Ag₃PO₄/SrTiO₃ (3AS sample) had a satisfactory photocatalytic activity for degrading methylene blue (MB) more than 98% under visible light irradiation. As to pure SrTiO₃ and Ag₃PO₄, only 9.8% and 49% of MB was decomposed after 35?min irradiation respectively. Furthermore, the mechanism of the enhancing photocatalytic activity could be ascribed to the nano-heterojunction of the Ag₃PO₄/SrTiO₃, the visible light response of the Ag₃PO₄, and the 1D structure of the nanowires.     

TiO2 nano-flakes with high activity obtained from phosphorus doped TiO2 nanoparticles by hydrothermal method

TiO₂ nano-wires (Ti-NWs) and nano-flakes (Ti-NFs) were obtained from phosphorus doped TiO₂ nanoparticles (Ti-P) by hydrothermal method and by subsequent heat treatment respectively. FE-SEM micrograph of the as prepared sample depicts well formed, entangled and randomly oriented nano-wires morphology, which changes to nano-flakes morphology after heat treatment. Structural characterization of the samples by X-ray diffraction shows anatase phase for both the samples. Absorption edge of the Ti-NWs sample shows blueshift where as the Ti-NFs sample exhibit redshift compared to precursor sample as evidenced by UV–Visible absorption spectra, which is due to change in morphology and crystallinity of the samples. XPS studies indicate the presence of titanium and oxygen species only. From the EPR measurements with in-situ visible light irradiation, the number of photogenerated charge carriers is found to be very high for nano-flakes sample. Methyleneblue degradation profiles depict very high activity of Ti-NFs sample compared to Ti-NWs and the precursor samples, which is due to the observed redshift in the absorption edge, change in morphology and high crystallinity of the sample which in turn increases the optical response and separation of photogenerated charge carriers as evidenced by the optical and EPR measurements respectively.     

Advanced visible-light photocatalytic property of biologically structured carbon/ceria hybrid multilayer membranes prepared by bamboo leaves

Biologically structured carbon/cerium dioxide materials are synthesized by biological templates. The microscopic morphology, structure and the effects of different oxidation temperatures on materials are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) ultraviolet-visible light spectrum (UV–Vis) and X-ray Photoelectron Spectroscopy (XPS). Moreover, by splitting water under visible light irradiation, the hydrogen production is measured to test the photocatalytic property of these materials. The results show that materials made with bamboo biological templates which are immersed in 0.1 mol L^?1 of cerium nitrate solution, then carbonizated in nitrogen (700 °C) and oxidized in air (500–600 °C), can obtain the biological structure of bamboo leaves. The product is in the composition of hybrid multilayer membrane, which one is carbon membrane form plant cell carbonation and another is ceria membrane by nanoparticle self assembly. The best oxidation temperature is 550 °C and the band gap of carbon/cerium dioxide materials synthesized at this optimum oxidation temperature could be reduced to 2.75 eV. After exposure to visible light for 6 h, the optimal hydrogen production is about 302 μmol g^?1, which is much higher than that of pure CeO₂.     

White light emission based on both upconversion and thermal processes from Nd3+ doped yttrium silicate

In the present study, white light emission based on both upconversion and thermal processes from single-phase yttrium silicate nanopowder doped with Neodymium (III) (Nd³⁺) was investigated at both room pressure and vacuum (0.01 mbar) with a diode laser excitation of 808 nm. 1% Nd³⁺ doped (per mole) yttrium silicate (Y₂O₃:SiO₂) nanopowder was synthesized by using the sol-gel method and annealed at 1250 °C for 12 h to obtain the powder form. Emission for upconverted white light mainly due to the transitions of Nd³⁺ ions was obtained below ~ 5.79 W of the laser beam power at atmospheric pressure. For powers exceeding ~ 5.79 W, the powder emitted a thermal white light (WL) due to the photon avalanche mechanism together with thermal processes. The threshold power to obtain thermal white light with the transitions of Nd³⁺ ions was decreased to ~ 3.51 W at the vacuum condition. These processes were investigated in detail by studying the spectral differences of the rise and decay patterns at atmospheric pressure and vacuum conditions.     

Microarray analysis of high light intensity stress on hydrogen production metabolism of Rhodobacter capsulatus

Biohydrogen obtained from purple non sulfur bacteria (PNSB) is an environmentally friendly alternative for hydrogen production. PNSB can be employed in large scale outdoor photobioreactors to produce hydrogen by photofermentation with sunlight as the light source. In external environmental conditions, however, bacteria can experience stress due to high light intensities, which can inhibit or slow down hydrogen production. Previous studies with other PNSB showed varying responses to light intensities (above 4000 lux), in some cases improving, and in others adversely affecting hydrogen production.In this study, Rhodobacter capsulatus, a PNSB species that produce hydrogen efficiently from dark fermenter effluents containing acetate, was used to investigate the effects of high light intensity stress on the hydrogen production metabolism at the gene expression level. A microarray analysis was carried out using a custom-design Affymetrix GeneChip TR_RCH2a520699F. R. capsulatus DSM1710 was grown under a cyclic illumination of 2000 and 7000 lux (12 h light/12 h dark) in a hydrogen production medium having 30 mM acetate and 2 mM glutamate, and was exposed to a high light intensity (10,000 lux) for 1 h in the middle of a light period. The results reveal that photosynthetic reaction center genes were down-regulated in order to protect the photosynthetic membrane from damage. On the other hand, the expression of nitrogenase and electron transport system genes were enhanced by high light intensity. These results show that a high light intensity stress drives R. capsulatus to direct gene expression towards hydrogen production, which supports the hypothesis that hydrogen production is a way for the disposal of excess reducing equivalents to maintain the internal redox balance.     

Sonochemical synthesis of PANI-BiVO4-GO semiconductor nanocomposite highly efficient visible-light photocatalytic performance

Abstract

Polyaniline/Bismuth Vanadate/Graphene Oxide (PANI-BiVO₄-GO) or BGPA composite was prepared by sonochemical deposition of bismuth vanadate-graphene oxide (BiVO₄) nanoparticles on the surface of polyaniline (PANI). The best photocatalytic degradation performance was obtained by 5wt% BGPA composites for MB, RhB, and SO dyes, which is approximately 4 times higher than that of 1% BGPA. Meanwhile, the photocatalytic stability of BiVO₄ was significantly improved by introducing PANI into the PANI-BiVO₄-GO composite. The dramatic promotion of the photocatalytic degradation performance and the photocatalytic stability can be attributed to the formation of a heterojunction free electron between PANI and BiVO₄-GO. The existence of those extra free electrons can dramatically enhance the efficiency of the photogenerated electrons, which accelerate the transfer of photogenerated holes from BiVO₄-GO to PANI, and therefore inhibit the self-oxidation of BiVO₄.     

Influence of doped platinum nanoparticles on photocatalytic performance of CuO–SiO2 for degradation of Acridine orange dye

Preparation of cupric oxide-silicon dioxide nanoparticles was carried out using a sol-gel method. Cupric oxide-silicon dioxide nanoparticles were decorated by different weight percent of platinum (0.5, 1.0, 3.0 and 5.0 wt %) using method of photoassisted deposition. XRD remarks revealed that XRD patterns for all samples are composed of cupric oxide. Therefore, silicon dioxide is amorphous and decoration of cupric oxide-silicon dioxide nanoparticles by platinum has no effect on the formed phase. Also, due to low percent of platinum there are no peaks for platinum oxide or platinum. Cupric oxide has bandgap energy absorb in visible region but has high e-h recombination rate. Decoration of cupric oxide-silicon dioxide nanoparticles by platinum was decreased bandgap energy from 2.38 to 1.91 eV and also decrease rate of e-h recombination rate. The photocatalytic activity of platinum decorated cupric oxide-silicon dioxide nanoparticles was measured under visible light for Acridine orange dye degradation. 100% of Acridine orange dye can be degraded using 3.0 wt % of platinum decorated cupric oxide-silicon dioxide photocatalyst, 1.2 g/L dose of platinum decorated cupric oxide-silicon dioxide photocatalyst and 30 min reaction time. 3.0 wt % of platinum decorated cupric oxide-silicon dioxide photocatalyst has photocatalytic stability for five times.     

Using d-limonene as the non-aromatic and non-chlorinated solvent for the fabrications of high performance polymer light-emitting diodes and field-effect transistors

Aiming to environment protection, green solvents are crucial for commercialization of solution-processed optoelectronic devices. In this work, d-limonene, a natural product, was introduced as the non-aromatic and non-chlorinated solvent for processing of polymer light-emitting diodes (PLEDs) and organic field effect transistors (OFETs). It was found that d-limonene could be a good solvent for a blue-emitting polyfluorene-based random copolymer for PLEDs and an alternating copolymer FBT-Th₄(1,4) with high hole mobility (μ_h) for OFETs. In comparisons to routine solvent-casted films of the two conjugated polymers, the resulting d-limonene-deposited films could show comparable film qualities, based on UV–vis absorption spectra and observations by atomic force microscopy (AFM). With d-limonene as the processing solvent, efficient blue PLEDs with CIE coordinates of (0.16, 0.16), maximum external quantum efficiency of 3.57%, and luminous efficiency of 3.66 cd/A, and OFETs with outstanding μ_h of 1.06 cm² (V s)⁻¹ were demonstrated. Our results suggest that d-limonene would be a promising non-aromatic and non-chlorinated solvent for solution processing of conjugated polymers and molecules for optoelectronic device applications.