M2M energy saving strategy in 5G millimeter wave system

Telecommunication Systems - Machine to Machine technology has a broad application prospect in the 5G network, but there is a bottleneck in the energy consumption of intelligent devices powered by...     

Experimental research on micro hole drilling of polycrystalline Nd:YAG

Polycrystalline Nd:YAG materials have wide applications in solid-state lasers. In this study, micro hole drilling experiments were performed on polycrystalline Nd:YAG using a polycrystalline diamond micro drill. The hole diameter, edge chipping, and hole wall surface quality were examined in detail. The results showed that the hole diameter was slightly larger than tool diameter. A diameter error of less than 5.5% was achieved. The edge chipping at the entry hole was formed by the encircled petal shape exfoliations, which were produced by the indentation and rotation movement in the drilling entry stage. Edge chipping at the exit hole was generated by an entire piece of exfoliation, which was produced by a circle of microcracks around the tool tip propagating to the bottom surface in the drilling exit stage. The edge chipping width at the entry hole was smaller than that at the exit hole. Based on different material removal modes, the hole surface morphology was classified into three types: ductile removal, coexisting ductile and brittle removal, and brittle removal. The hole surface quality mainly depended on the proportion of the brittle fracture to ductile removal surface.     

妈祖文化视域下的表情符号设计研究

目的 基于妈祖文化的视角,探究妈祖文化与表情符号设计融合的可能性,打造表情文化产业链,为表情符号的设计开发提供更多的机遇,推动了妈祖文化的对外传播.方法 以妈祖文化为切入点,分析表情符号设计与妈祖文化跨界融合发展的优势.同时,借助具体的案例来阐述两者结合所产生的积极意义,表明巧妙应用妈祖文化的可行性.结论 妈祖文化的融入为表情符号的发展增添了浓墨重彩的一笔,对于增强文化气息及开拓设计思路都发挥着重要作用,易于激发受众的情绪、记忆,引起受众情感和心理的共鸣,从而创造符合受众审美情趣和思维方式的设计作品.由此可见,深入把握两者的关联性,有助于催生新的文化产业形态、传承妈祖文化、开辟表情符号设计新路径.     

Evidence on the induction of viable but non-culturable state in Listeria monocytogenes by Origanum vulgare L. and Rosmarinus officinalis L. essential oils in a meat-based broth

Induction of viable but non-culturable (VBNC) state in Listeria monocytogenes by Origanum vulgare L. (OVEO) and Rosmarinus officinalis L. essential oils (ROEO) in a meat-based broth and phosphate-buffered saline was investigated. Occurrence of culturability loss on brain-heart infusion agar in L. monocytogenes cells (approximately 7 log CFU/mL) exposed to OVEO (5 and 2.5 μL/mL) or ROEO (10 and 5 μL/mL) individually in meat broth and phosphate-buffered saline, and their ability to restore culturability during a recovery treatment in phosphate-buffered saline + glucose (6 or 24 h, 30 °C) was evaluated. Viability of cells exposed to OVEO and ROEO was investigated with measurements of damage on integrity and membrane potential and enzymatic, efflux pump and respiratory activities. L. monocytogenes lost culturability after a 60 or 180 min-exposure to OVEO (5 and 2.5 μL/mL) or ROEO (10 and 5 μL/mL) in phosphate-buffered saline and meat broth. Cells exposed to ROEO in meat broth (5 and 10 μL/mL) and phosphate-buffered saline (5 μL/mL) restored culturability after 24 h of recovery treatment. Cells with lost culturability had variable subpopulation sizes (10.8–98.5%) with damage on measured physiological functions. Cells with lost culturability induced by OVEO or ROEO had improvements in physiological functions during recovery treatment, being indicative of viability. These results indicate that OVEO and ROEO could cause VBNC state in L. monocytogenes.     

(Metal yolk)/(porous ceria shell) nanostructures for high-performance plasmonic photocatalysis under visible light

We describe a route to the preparation of (metal yolk)/(porous ceria shell) nanostructures through the heterogeneous growth of ceria on porous metal nanoparticles followed by the calcination-induced shrinkage of the nanoparticles. The approach allows for the control of the ceria shell thickness, the metal yolk composition and size, which is difficult to realize through common templating approaches. The yolk/shell nanostructures with monometallic Pt and bimetallic PtAg yolks featuring plasmon-induced broadband light absorption in the visible region are rationally designed and constructed. The superior photocatalytic activities of the obtained nanostructures are demonstrated by the selective oxidation of benzyl alcohol under visible light. The excellent activities are ascribed to the synergistic effects of the metal yolk and the ceria shell on the light absorption, electron-hole separation and efficient mass transfer. Our synthesis of the (metal yolk)/(porous ceria shell) nanostructures points out a way to the creation of sophisticated heteronanostructures for high-performance photocatalysis.

     

The Effect of Noble-Metal Deposition Routes on the Characteristics and Photocatalytic Activity of M-TiBi1.9%O2 (M = Pt and Pd)

Topics in Catalysis - The effect of deposited noble-metals and their deposition routes on the photocatalytic decomposition of organic pollutants over M-TiBi1.9%O2 (M?=?Pt and Pd) under...     

Research on the machinability of A-plane sapphire under diamond wire sawing in different sawing directions

Due to its superior mechanical, optical and chemical properties, sapphire (α-Al₂O₃) is widely used in engineering, optics, medicine, and other scientific research fields. The atomic structure of sapphire gives rise to anisotropy in its mechanical properties, which affects the machinability of sapphire materials on different crystal planes. Different cutting directions will affect the wafer economy and surface quality achieved during wire sawing due to this anisotropy. In this study, the machinability of A-plane sapphire was investigated for diamond wire sawing in three different directions, following the C-plane, R-plane and M-plane. The results show that the direction following the M-plane could be the best direction for diamond wire sawing because this direction results in the minimal sawing forces, the lowest specific energy and the smallest volume of material that will need to be removed during subsequent processing. These characteristics correspond to the direction with the highest fracture strength since the material is removed by brittle machining. The force ratio for sawing in the direction of the R-plane is the smallest because this direction is associated with the minimum hardness and the lowest critical load for the transition from plastic to brittle removal of the workpiece material. The 3D height parameters show no obvious pattern among the three sawing directions. The mechanism of material removal is mainly brittle removal, with some plastic removal, and is obviously affected by the crystal orientation.     

Deep-blue thermally activated delayed fluorescence emitter with a very high fluorescence rate

Conventional thermally activated delayed fluorescence (TADF) molecules achieve small energy differences between the lowest singlet and triplet excited states (ΔE_ST) by enhancing the intramolecular charge transfer, which inevitably leads to a wide emission spectrum and low fluorescence rate. Here, we prepared a deep blue TADF molecule via a small ΔE_ST pyridine-phenol fluoroboron complex as the acceptor. The small ΔE_ST is maintained when carbazole donors are attached to the 4-position of the phenyl rings in the fluoroboron complex. Benefiting from the strong electron coupling between the donor (D) and acceptor (A) moieties, the compound Cz-4-BF exhibits a high fluorescence rate of 4.8 × 10⁸ s⁻¹ and a small D-A dihedral angle change in the excited state. Consequently, a photoluminescence (PL) quantum yield of nearly 100% and a PL spectrum with full-width at half-maximum (FWHM) < 60 nm were obtained in solution and low-concentration doped films. A TADF-sensitized fluorescence (TSF) device containing Cz-4-BF achieves an external quantum efficiency of 21%, which is higher than the devices employing classical fluorescent emitters and multiple resonance-type TADF emitters. The Cz-4-BF-based TSF device shows significantly improved color coordinates of (0.14, 0.10) versus a control device without Cz-4-BF.