Due to sectoral interactions in the economy,the overall green efficiency(GE)of China’s industrial system relies heavily on fundamental sectors that contribute substantial energy to the supply chain production of othe...
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Due to sectoral interactions in the economy,the overall green efficiency(GE)of China’s industrial system relies heavily on fundamental sectors that contribute substantial energy to the supply chain production of other sectors but shows low sectoral *** the three fundamental sectors in China’s industrial systems,namely the smelting and pressing of nonferrous metals(SPNFM),the processing of petroleum,coking,and nuclear fuel(PPCNF);and the manufacturing of nonmetallic mineral products(MNMMP),we employed a three-stage data envelopment analysis(DEA)model to measure GE in the fundamental sectors in 30 provinces from 2010 to *** then adopted a stochastic frontier analysis(SFA)model to evaluate the influence of technological innovation(TI),industrial agglomeration(IA),environmental regulation(ER),and intraindustry competition(IC).The results showed that GE in the three fundamental sectors varied ***,TI promoted GE in MNMMP,but the effect was not obvious in the SPNFM and PPCNF ***,ER had positive impacts on GE in the fundamental *** effects of IA and IC on GE in the fundamental sectors varied in direction and *** eliminating the impacts of environmental effects and statistical noise,the real GE in the three fundamental sectors varied significantly compared to the comprehensive *** opportunities for enhancing GE in the fundamental sectors mainly lie in region-specific policy and regulations that avoid a“one-size-fits-all”governance approach.
Real-world emission tests were undertaken on 30 tractors and 9 corn combine harvesters by using a portable emission measurement system (PEMS) to better understand the emissions of typical agricultural machinery. The r...
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Light-duty gasoline vehicles have drawn public attention in China due to their significant primary emissions of particulate matter and volatile organic compounds(VOCs). However,little information on secondary aeroso...
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Light-duty gasoline vehicles have drawn public attention in China due to their significant primary emissions of particulate matter and volatile organic compounds(VOCs). However,little information on secondary aerosol formation from exhaust for Chinese vehicles and fuel conditions is available. In this study, chamber experiments were conducted to quantify the potential of secondary aerosol formation from the exhaust of a port fuel injection gasoline engine. The engine and fuel used are common in the Chinese market, and the fuel satisfies the China V gasoline fuel standard. Substantial secondary aerosol formation was observed during a 4–5 hr simulation, which was estimated to represent more than 10 days of equivalent atmospheric photo-oxidation in Beijing. As a consequence, the extreme case secondary organic aerosol(SOA) production was 426 ± 85 mg/kg-fuel, with high levels of precursors and OH exposure. The low hygroscopicity of the aerosols formed inside the chamber suggests that SOA was the dominant chemical composition. Fourteen percent of SOA measured in the chamber experiments could be explained through the oxidation of speciated single-ring aromatics. Unspeciated precursors, such as intermediate-volatility organic compounds and semi-volatile organic compounds, might be significant for SOA formation from gasoline VOCs. We concluded that reductions of emissions of aerosol precursor gases from vehicles are essential to mediate pollution in China.
The surface microstructures of some organisms in nature have some unexpected properties and functions, such as the self-cleaning ability of lotus leaves. Inspired by these special properties of living things, people b...
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The surface microstructures of some organisms in nature have some unexpected properties and functions, such as the self-cleaning ability of lotus leaves. Inspired by these special properties of living things, people began to combine these special properties with practical applications to fabricate biomimetic surfaces, which can improve product performance. However, how to accurately and massively prepare bionic microstructures remains challenging. The potential to produce biomimetic microstructure surfaces with precise and large-scale industrialization of femtosecond laser processing technology that has the advantages of extremely short pulse duration, high energy density, negligible heat-affected zone, and high resolution. Friction and wear is one of the common problems in mechanical equipment. How to solve the problem is extremely urgent, and the solution of the problem using femtosecond laser has great significance for future production and life. In this paper we describe a method for preparing periodic surface structures with superhydrophobicity by controlling the fluence of femtosecond laser and surface texture cycles on stainless steel surfaces and then analyze the relationship between superhydrophobicity and friction properties on prepared microstructure surfaces. The experimental results show that the laser induced periodic surface structures induce changes in the surface hydrophobicity and surface friction properties of the stainless steel surfaces.
We experimentally studied droplet impact dynamics onto wing feathers of kingfishers. Distilled water droplets with a fixed diameter of 2.06 mm were used as drop liquid and the initial impact velocities of droplets var...
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We experimentally studied droplet impact dynamics onto wing feathers of kingfishers. Distilled water droplets with a fixed diameter of 2.06 mm were used as drop liquid and the initial impact velocities of droplets varied from 0.28 m· s^-1 to 1.60 m·s^-1. Two high-speed cameras were utilized to capture the impact process of water droplets onto the wing feather surface from both horizontal and vertical directions. Two states of the feathers (elastic and inelastic) were considered to study the influence of elasticity. At the entire impact ve- locity range we studied, regular rebound, bubble trapping and jetting, partial pinning and partial rebound of droplets on inelastic wing feather surface were observed as the initial impact velocity increased. However, only one dynamic behavior (regular rebound) was found on the elastic wing feather surface. The elasticity plays a more important role in the direction difference of droplet spreading than wing feather microstructure. The contact time of water droplets on the elastic wing feather surface was less than that on the inelastic surface within the range of Web numbers from 1.06 to 36 under test conditions.
Switchable superamphiphobic surfaces have attracted considerable attention due to their potential applications in droplet manipulation, fluid carrier devices, rewritable liquid patterns and lab-on-a-chip devices. Howe...
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Switchable superamphiphobic surfaces have attracted considerable attention due to their potential applications in droplet manipulation, fluid carrier devices, rewritable liquid patterns and lab-on-a-chip devices. However, there are few reports about switchable superamphiphobic surfaces of which the wettability can be transformed by controlling the deformation of the micro-structures. Inspired by springtails which have omniphobic surfaces consisting of mushroom-shaped nano-structures, we fabricated a superomniphobic surface with mushroom-shaped micro-structures. First, mixing polydimethylsiloxane(PDMS) pre-polymer containing 5 wt% curing agents and carbonyl iron microspheres. Then, the mixture was coated on a glass substrate followed by fixing a fluorinated flat plate at 200-400 μm above the substrate. After that, a permanent magnet was left below the substrate, and the carbonyl iron microspheres arranged along the direction of magnetic field, leading to the formation of the mushroom-shaped pillars. The whole assembly was left in drying oven for the curing of the mixture. Subsequently, the fluorinated flat plate was removed, and the mushroom-shaped pillar arrays were silanized using 1H,1H,2H,2H-perfluorodecyltrichlorosilane. The wettability of the obtained superamphiphobic surface was switchable. By changing the direction of the external magnetic field, the mushroom-shaped pillars can be reversibly deformed between upright and curved states. Therefore, the wetting state of water on the superamphiphobic surfaces can be switched between a superhydrophobic state and a hydrophobic state. The wetting state of hexadecane on the superamphiphobic surfaces can be switched between a superoleophobic state and an oleophobic state. It is believed that the fabrication approach will promote the large-scale fabrication of switchable superamphiphobic surface with deformable pillar arrays.
Flying in the rain presents a greater challenge for smaller animals such as kingfishers, compared with aircraft in the same situation. Regardless, kingfishers have developed advanced water repellency as reflected in t...
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Flying in the rain presents a greater challenge for smaller animals such as kingfishers, compared with aircraft in the same situation. Regardless, kingfishers have developed advanced water repellency as reflected in the hydrophobicity and elasticity of their feathers. Therefore, it is possible to confirm that the elastic superhydrophobic surface can enhance the water repellency of the surface by experimental and theoretical analysis. A simplified device simulating droplet impact on a kingfisher feather was configured for comparison. Moreover, the dynamic behavior of droplets(with varying Weber numbers—2≤We≤42) impinging on the elastic and rigid substrate was analyzed, such as spreading, retraction, lift-off, the secondary droplet, and contact time with a high-speed camera. The elastic substrate significantly affected the retraction and lift-off of the droplet—that is, an earlier and more efficient morphological rearrangement of the droplet—reducing the contact time by up to 8.3%(17
Self-secretion material of lubricant have attracted considerable attention due to their potential application in precision instruments, bionic joints and the improvement of machine lubrication *** nature, many organis...
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Self-secretion material of lubricant have attracted considerable attention due to their potential application in precision instruments, bionic joints and the improvement of machine lubrication *** nature, many organisms have the function of self-secretion of lubricant, such as earthworm lubricant releasing gland and ox knee joint *** anti-wear materials have been reported in recent studies, most materials cannot produce self-secreting lubricant. In contrast, there are a few reports about self-secretion material of lubricant of which the lubricant was embedded in the materials,and lubricant is secreted under certain conditions. Here, we have developed a temperature-sensitive self-secretion material, which is expected to be applied in many fields. First, a kind of shape memory polyurethane(SMPU) material was synthesized by solution *** films for the measurement of tensile properties were prepared by casting SMPU solutions in dimethylformamide(DMF) into a mould. The mold is a cylindrical array structure made of medium carbon steel by laser engraving with a diameter of 20 μm and a height of 100 μm, the spacing of the cylindrical array is 100 μ*** evaporation of the solvent at 80 °C for 24 h, the films obtained were further dried at 60 °C under vacuum for another 48 h. Material is stretched at 60 ℃, keep the external force at 20 ℃ for 10 min, the shape of the material is *** put grease injection in the pores of the material. Finally, when the friction experiment is carried out on the material, the material temperature increases with the heat generated by the friction, when the temperature at 30 ℃, the shape back to the front of the *** volume of the microporous decreasing, then the lubricating oil is squeezed out.
The stress-strain and hemodynamic distribution of the distal stenotic artery are remarkably influenced by the number and length of plaques. To investigate the mechanism of distal restenosis in the stenotic femoral art...
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The stress-strain and hemodynamic distribution of the distal stenotic artery are remarkably influenced by the number and length of plaques. To investigate the mechanism of distal restenosis in the stenotic femoral artery, the effects of the stenosis throat on the distribution of flow patterns have been evaluated. Based on the finite element method, the fully-coupled fluid-structure interaction(FSI) analysis was conducted for four idealized wall/blood models under the physiologically realistic inlet velocity. The results showed that the peak wall stress existed in the vicinity of the lesion stenosis area at the peak of the velocity compared with the farthest end of the blood vessel, which could damage and destroy the endothelial cells and provide favorable conditions for the formation of atherosclerotic plaques. Moreover, the restenosis of the femoral artery could be triggered by large deformation at the distal end of the stenosis after peak systolic flow, which was more probably to occur when the vessels were segmental and diffuse. The study helps to raise awareness of preventing distal restenosis in the stenotic femoral artery and providing the biomedical engineering basis for the research community to determine early targeted therapies.
The serious air pollution problems in China have significantly affected the development of China’s economy and society,especially in key areas such as Beijing-Tianjin-Hebei,Yangtze River Delta,and Pearl River Delta,w...
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The serious air pollution problems in China have significantly affected the development of China’s economy and society,especially in key areas such as Beijing-Tianjin-Hebei,Yangtze River Delta,and Pearl River Delta,which has aroused widespread concern throughout *** the launch of the MOST(Ministry Of Science and Technology)key project for Air Pollution Formation Mechanism and control Technology during the 13thFive-Year Plan.
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