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How to form the cutting groove safely and quickly has always been a technical problem when the sublevel caving is applied to the soft broken rock conditions. Firstly, the incompatibility of the traditional cutting groove scheme-"cutting raise firsthand then cutting groove" under the condition of soft and broken rock mass is analyzed, and the advantages, disadvantages and the applicable conditions of several commonly used non-raise grooving schemes are summarized. In view of the mining conditions of using the sublevel caving in the condition of soft and broken rock in the West Second Mining Area of Jinchuan Longshou Mine, a non-raise rapid grooving scheme of "cutting tunnel + wedge shaped blast holes grooving + vertical parallel blast holes expansion groove" is adopted. Meanwhile, this scheme can also realize that only one wedge-shaped blasting is performed in the entire sublevel, and the cutting groove work of whole sublevel can be completed quickly and conveniently. Therefore, the efficiency and reliability of the cutting groove during mining by the sublevel caving are greatly improved under the condition of soft and broken rock. Finally, the scheme was applied in the mine, and the scheme was optimized according to the actual application situation, and good application results were achieved. [ABSTRACT FROM AUTHOR]

C5F10O has been widely studied as a great potential alternative gas to SF6, a most potent industrial greenhouse gas that is predominantly used as an insulating medium in electrical equipment, due to its excellent insulation properties and environmental characteristics. Several experimental and theoretical attempts have been made and have obtained valuable results in the last five years. However, few researchers have thoroughly investigated the decomposition mechanism and the main decomposition pathways of the C5F10O/H2O system, which are important for evaluating the insulating and environmental performance and providing guidance for engineering application. Herein, the decomposition characteristics and mechanism of C5F10O in the presence of moisture content was studied by density functional theory calculations. The main types of decomposition products with relatively high content have been summarized based on the evaluation of cleavage reactions and the influence of moisture. The electrical, environmental and safety performances of the primary products were analyzed. CF3CFCF3, CF3CO, CF3, OH and H radicals are the most primary particles formed by dissociation of C5F10O and H2O. These particles may further convert into more than 20 kinds of relatively stable products, among which C4F10, C3F8, C6F14, C3HF7, C2F6 and CO are primary ones. In addition, COF2, CO2, CO and C3F6 can be used as components for estimating the degree of failures. The existence of H2O has a negative impact on the insulation and environmental performance. In particular, trace water has a direct contribution to the production of highly toxic COF2, CO and HF. Thus, it is necessary to strictly control the moisture and develop application standards before any industrial application of C5F10O in electrical equipment. [ABSTRACT FROM AUTHOR]

An experimental and testing platform was established to comparative study the decomposition characteristic of SF6 under different voltage waveform (negative direct current (DC) voltage, positive DC voltage, and alternating voltage), and investigate the influence of pressure and adsorbent. Content variation of typical products under different conditions and the influence mechanism were observed and analysed in detail. The results indicate that SF6 decomposition characteristics are closely related to a voltage waveform, pressure, and adsorbent. Concentrations of by‐products under AC voltage are higher than those under DC voltage and SF6 decomposes more easily under positive voltage than negative voltage, which can be explained by different discharge energy and distribution characteristic of space charges. The values of typical products show an obvious downward trend with pressure due to falling discharge energy, volume of active region and dissociation rate of SF6. Concentrations of typical products including SOF2, SO2F2, and SO2 decrease dramatically after adding adsorbents because of physical absorption and chemisorption. [ABSTRACT FROM AUTHOR]

Detection of decomposition products is a widely studied method for condition diagnosis of SF6 insulated equipment because of its anti-electromagnetic interference and high sensitivity. A 90 L discharge chamber with adjustable defect was designed to simulate typical failures including metal protrusion defect, floating potential defect and insulator defect. Primary products of both the former two defects are SOF2, SO2F2, CO2, and SO2. Concentration ratios including Φ(SOF2+SO2F2+SO2)Φ(CO2) and Φ(SOF2+SO2)/Φ(SO2F2) could be used to distinguish these two defects which have different structures and discharge energy. Influence of essential conditions such as applied voltage, pressure, and moisture content has been investigated under metal protrusion defect. For the insulator defect, several extra carbon containing by-products, namely, CF4, CO, and CS2, are found to be critical characteristic decomposition products. Moreover, a triangle method utilizing composition of decomposition products is proposed. It is proved to be a graphical method which helps to follow the faults more easily and more precisely. [ABSTRACT FROM AUTHOR]

Dialysis is a well-known technique for laboratory separation. However, its efficiency is commonly restricted by the dialyzer volume and its passive diffusion manner. In addition, the sample is likely to be precipitated and inactive during a long dialysis process. To overcome these drawbacks, a dynamic dialysis method was described and evaluated. The dynamic dialysis was performed by two peristaltic pumps working in reverse directions, in order to drive countercurrent parallel flow of sample and buffer, respectively. The efficiency and capacity of this dynamic dialysis method was evaluated by recording and statistically comparing the variation of conductance from retentate under different conditions. The dynamic method was proven to be effective in dialyzing a large-volume sample, and its efficiency changes proportionally to the flow rate of sample. To sum up, circulating the sample and the buffer creates the highest possible concentration gradient to significantly improve dialysis capacity and shorten dialysis time. [ABSTRACT FROM PUBLISHER]

With the development of smart grids, efficient condition monitoring of high voltage transmission system has become crucial, necessitating reliable power supplies for distributed sensors. Traditional energy harvesters often focus on either internal or external sources, limiting overall efficiency. This study introduces a triboelectric‐electromagnetic‐electric field hybrid energy harvester (TEE‐HEH) that synergistically integrates triboelectric nanogenerators (TENGs), electromagnetic generators (EMGs), and electric field energy harvesters (EEHs) to simultaneously capture electric field and wind energy. Electric field energy is harvested via displacement currents between transmission lines and the ground, while TENGs and EMGs efficiently capture low‐ and high‐speed wind energy, respectively, enabling broadband harvesting (2.3–10 m s−1). The synergistic combination of TENG, EMG, and EEH within the TEE‐HEH leads to significantly enhanced energy capture efficiency from multiple sources. At a wind speed of 5 m s−1, a transmission line voltage of 25 kV, and a distance of 1.5 m, the TEE‐HEH achieved peak power outputs of 18.5 mW (TENG), 262 mW (EMG), and 1.85 mW (EEH), demonstrating enhanced energy collection efficiency. An environmental monitoring system has been powered, demonstrating the TEE‐HEH's practicality for dual‐source energy harvesting in smart grid applications. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerator (TENG) has received significant attention as an energy harvesting technology capable of converting mechanical energy from the environment into electrical power. However, due to its inherent high impedance and low charge transfer output characteristics, the output of TENG is often relatively small. Current research typically focuses on switching on and off under intrinsic voltage for performance management. To further improve output performance, an energy management strategy is proposed that aimed at voltage boosting in this study. This strategy ingeniously designs the discharge sequence of two discharge switches to adjust the connection between the intrinsic capacitor and the matched capacitor, thereby facilitating instantaneous charge transfer under voltages surpassing the intrinsic voltage and significantly enhancing the power density. Combining this strategy with a power converter has significantly enhanced the energy storage efficiency of capacitors, thereby enabling improved power supply for sensor devices. Moreover, experimental results show a power density of 324.8 kW m−2, indicating a 100% increase compared to the direct discharge strategy. With such high output power, five parallel 10‐watt commercial lamps can be illuminated. This strategy introduces a novel idea for achieving high performance output from TENG. [ABSTRACT FROM AUTHOR]

As fluorescence in the second near-infrared window (NIR-II, 1000-1400 nm) could image deep tissue with high signal-to-noise ratios compared with that in NIR-I (750-900 nm), Ag 2 Se quantum dots (QDs) with fluorescence in the NIR-II could be ideal fluorophores. Here, we described a biosynthesis method to prepare the Ag 2 Se QDs by using temporally coupling the irrelated biochemical reactions, whose photoluminescence (PL) emission can reach NIR-II. The nanoparticles were characterized by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). The results showed that the nanoparticles obtained by extracellular purification were Ag 2 Se QDs with a uniform size of 3.9 ± 0.6 nm. In addition, the fluorescence intensity of Saccharomyces cerevisiae was improved successfully by nearly 4-fold by constructed engineering strain. In particular, the biosynthesis of Ag 2 Se QDs had good biocompatibility because it was capped by protein. Furthermore, investigating the toxicity of Ag 2 Se on cells and NIR images of nude mice showed that the Ag 2 Se synthesized using S. cerevisiae had low toxicity and could be used for in vivo imaging. In this work, the synthesis pathway of biocompatible Ag 2 Se was broadened and laid a foundation for the enlarged applicability of bioimaging in the biosynthesis of NIR-II QDs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)