This study investigates whether and how government decentralization affects firms' pollution emissions. To identify causality, we introduce a triple-difference strategy based on a natural experiment ...launched by the central government of China, i.e., the "Province-Managing-County" fiscal reform, which aims to eliminate the prefecture government as the intermediate layer between province and county. We show that the PMC fiscal reform increases firms' pollution emissions. Our findings are particularly pronounced for firms located in Eastern China and in provinces with high-level marketization. Welfare analysis exhibits that decentralization-induced pollution on PM2.5 leads to around 449-663 increase in death every year at the county-level.
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MXenes are regarded as promising electrode materials for lithium-ion batteries owing to their high electrical conductivity and two-dimensional structure but suffer from low intrinsic ...specific capacities. In this study, we fabricate sulphur-doped multilayer Ti3C2Tx MXenes via calcination and annealing using sublimed sulphur as the sulphur source. After sulphur doping, the interlayer spacing of Ti3C2Tx increases, which is favourable for Li-ion insertion. The Ti3C2Tx MXene@S composite exhibits excellent electrochemical performance. A high reversible specific capacity of 393.8 mAh g−1 at a current density of 100 mA g−1 after 100 cycles is obtained. Additionally, a negative fading phenomenon is observed when the specific capacity increases to 858.9 mAh g−1 after 2550 cycles at 1 A g−1 and to 322.2 mA h g−1 after 3600 cycles at 5 A g−1 from the initial 267.3 mAh g−1. We systematically investigate the effects of two different binders (polyvinylidene difluoride and carboxymethyl cellulose, hereinafter abbreviated as PVDF and CMC, respectively) on the electrochemical performance of the Ti3C2Tx MXene@S composite and discovered that the electrode using the CMC binder exhibits better lithium-ion storage performance than that using the PVDF binder, which is attributed to the lower charge transfer resistance, higher ion diffusivity, and enhanced adhesion force.
Proton Exchange Membrane Fuel Cell (PEMFC) is widely recognized for its cleanliness and high efficiency, but is still facing challenges in cold environments. At low temperatures, the formation of ice ...and repeated freezing/thawing cycles may cause cell performance reduction and irreversible degradation. The cathode flow field of PEMFCs has a significant effect on the performance. In contrast to the conventional “channel-ridge” flow field, the metal foam has the advantages of excellent pre-distribution of gases and water drainage, which make it a promising candidate for the cold start. This paper examines the cold start of PEMFCs with metal foam flow field (MFFF) and serpentine flow field (SFF), and the influence of constant current mode, constant voltage mode, and ramping current mode is investigated experimentally through performance test and electrochemical characterization. The results show that lowering the voltage and increasing the current can enhance the cold-start performance of fuel cells. The MFFF fuel cell has superior cold start performance compared to the SFF fuel cell under the constant voltage mode of 0.3 V. Furthermore, the variable current mode is developed by considering the distinct properties of heat and water production during various phases, and the results indicate that increasing the current density at the unsaturated stage leads to an elevated rate of heat production and a reduced rate of water production, which can improve the cold start of PEMFCs.
•The cold start of PEM fuel cells with metal foam flow fields is studied.•The influence of startup modes is investigated through experimental testing.•Increasing current and decreasing voltage result in higher rate of temperature rise.•Variable current mode is designed to balance water and heat generation in cold start.•Increasing current density in the unsaturated stage improves cold start performance.
This paper reports the development of a highly efficient, flexible hardware platform, which is suitable for the control of spin-based quantum systems including quantum computation and quantum ...metrology. A two-channel arbitrary waveform generator (AWG), an eight-channel pulse/sequence generator, a two-channel analog-to-digital converter (ADC), and a two-channel high-speed time-to-digital converter (TDC) are fully integrated on a printed circuit board (PCB). The AWG has a 1-GSa/s sampling rate and a 16-bit amplitude resolution. The pulse/sequence generator can continuously output pulse/sequence signals with a 50-ps time resolution and a dynamic range from 5 ns to 2 s. The ADC provides a 1-GSa/s sampling rate and a 12-bit amplitude resolution for analog signal acquisition. The TDC provides a 6-ps time resolution and a maximum sampling frequency of 125 MHz. All these modules are realized utilizing a field-programmable gate array (FPGA). Customized data calculation modules are also implemented with the FPGA logic. The hardware was tested and implemented in a pulsed electron spin resonance (ESR) spectrometer and an optically detected magnetic resonance (ODMR) spectrometer.
Metal foam (MF) flow field has extensive potential in proton exchange membrane fuel cells (PEMFCs). Under its influences on the internal flow and heat/mass transfer in PEMFCs, the original electrode ...structure base on the “channel-rib” flow field could be no longer suitable. In this study, the effects of gas diffusion layer (GDL) parameters on the cold start of PEMFCs with MF flow fields are studied experimentally. We focus on the pore size distribution and hydrophobicity of the GDL and investigate their effects on the cold start performance, the cell impedance, and the cell degradation. The results show that GDLs with large pore diameter and smooth pore size gradient are helpful to enhance the cold start performance and reduce the cell degradation due to the small mass-transfer resistance and excellent water/ice-storage capacity. In addition, the cell of GDL with moderate hydrophobicity has the best cold start performance at -5 °C as it can well balance the resistance of water transfer in GDL and from CL into GDL. Below -5 °C, a stronger GDL hydrophobicity can lead to a longer cell operating time and better cell stability. This is mainly because the GDL hydrophobicity can significantly affect the reactant flow path and the internal water freezing. The results of this study provide physical insight into the electrode optimization for improving the cold start of PEMFCs with MF flow fields.
•Effects of GDL parameters on the cold start of PEMFCs are studied experimentally.•GDLs with large pore diameter and smooth pore size distribution are favorable.•GDLs with moderate hydrophobicity have the best cold start performance above -5 °C.•Enhancing GDL hydrophobicity improves performance at extremely subzero temperature.•Optimized GDL can alleviate icing in PEMFC cold start and reduce cell degradation.
•Multi-compartmentation of the interiors of protein nanoparticles was reported.•Internalization of eugenol against protein nanoparticles created compartments.•Gelled protein chains inside the ...construct formed delimited physical barriers.•The construct enabled controllable responses of a payload to the outer conditions.
Multicompartmented nanostructures, which mirror the complexity of living cells, are promising for bio-related applications. However, controlling the spatial arrangement within natural biopolymer assemblies, like protein nanoparticles, is challenging. In our study, we reveal a facile method for compartmentalizing the interiors of protein nanoparticles by co-assembling rice proteins (RPs) and soy protein isolates (SPIs) through simultaneous folding. The assembly of these two protein types results in nanoparticles with a hydrophobic core to accommodate hydrophobic substances, such as eugenol, leading to its internalization. The protein–ligand (SPI-eugenol) interaction then triggers SPI gelation within the nanoparticle cores, forming distinct physical barriers hindering the complete merging of eugenol droplets. Subsequent dialysis of the nanoparticles containing eugenol against water facilitated the removal of eugenol. This step was crucial for forming multicompartmented nanoparticles (MCNPs) with adjustable interior complexities, including varying numbers of compartments and different hollowing rates related to various SPI:RP mass ratios. This allows us to endow MCNPs with adjustable barrier effects tailoring controllable responses of the encapsulated payload, vitamin D3 (VD3), under different physicochemical conditions. Our study demonstrates a straightforward method for constructing biomacromolecular architectures with precise control over their compartmentalization.
The catalytic behavior of CO hydrogenation can be modulated by metal–support interactions, while the role of the support remains elusive. Herein, we demonstrate that the presence of strong ...metal–support interactions (SMSI) depends strongly on the crystal phase of TiO2 (rutile or anatase) and the treatment conditions for the TiO2 support, which could critically control the activity and selectivity of Ru-based nanocatalysts for CO hydrogenation. High CO conversion and olefin selectivity were observed for Ru/rutile-TiO2 (Ru/r-TiO2), while catalysts supported by anatase (a-TiO2) showed almost no activity. Characterization confirmed that the SMSI effect could be neglected for Ru/r-TiO2, while it is dominant on Ru/a-TiO2 after reduction at 300 °C, resulting in the coverage of Ru nanoparticles by TiOx overlayers. Such SMSI could be suppressed by H2 treatment of the a-TiO2 support and the catalytic activity of the as-obtained Ru/a-TiO2(H2) can be greatly elevated from almost inactive to >50% CO conversion with >60% olefin selectivity. Further results indicated that the surface reducibility of the TiO2 support determines the SMSI state and catalytic performance of Ru/TiO2 in the CO hydrogenation reaction. This work offers an effective strategy to design efficient catalysts for the FTO reaction by regulating the crystal phase of the support.
The catalytic behavior of CO hydrogenation can be modulated by metal-support interactions, while the role of the support remains elusive. Herein, we demonstrate that the presence of strong ...metal-support interactions (SMSI) depends strongly on the crystal phase of TiO
(rutile or anatase) and the treatment conditions for the TiO
support, which could critically control the activity and selectivity of Ru-based nanocatalysts for CO hydrogenation. High CO conversion and olefin selectivity were observed for Ru/rutile-TiO
(Ru/r-TiO
), while catalysts supported by anatase (a-TiO
) showed almost no activity. Characterization confirmed that the SMSI effect could be neglected for Ru/r-TiO
, while it is dominant on Ru/a-TiO
after reduction at 300 °C, resulting in the coverage of Ru nanoparticles by TiO
overlayers. Such SMSI could be suppressed by H
treatment of the a-TiO
support and the catalytic activity of the as-obtained Ru/a-TiO
(H
) can be greatly elevated from almost inactive to >50% CO conversion with >60% olefin selectivity. Further results indicated that the surface reducibility of the TiO
support determines the SMSI state and catalytic performance of Ru/TiO
in the CO hydrogenation reaction. This work offers an effective strategy to design efficient catalysts for the FTO reaction by regulating the crystal phase of the support.
The catalytic behavior of CO hydrogenation can be modulated by metal-support interactions, while the role of the support remains elusive. Herein, we demonstrate that the presence of strong ...metal-support interactions (SMSI) depends strongly on the crystal phase of TiO
2
(rutile or anatase) and the treatment conditions for the TiO
2
support, which could critically control the activity and selectivity of Ru-based nanocatalysts for CO hydrogenation. High CO conversion and olefin selectivity were observed for Ru/rutile-TiO
2
(Ru/r-TiO
2
), while catalysts supported by anatase (a-TiO
2
) showed almost no activity. Characterization confirmed that the SMSI effect could be neglected for Ru/r-TiO
2
, while it is dominant on Ru/a-TiO
2
after reduction at 300 °C, resulting in the coverage of Ru nanoparticles by TiO
x
overlayers. Such SMSI could be suppressed by H
2
treatment of the a-TiO
2
support and the catalytic activity of the as-obtained Ru/a-TiO
2
(H
2
) can be greatly elevated from almost inactive to >50% CO conversion with >60% olefin selectivity. Further results indicated that the surface reducibility of the TiO
2
support determines the SMSI state and catalytic performance of Ru/TiO
2
in the CO hydrogenation reaction. This work offers an effective strategy to design efficient catalysts for the FTO reaction by regulating the crystal phase of the support.
Ru/TiO
2
nanocatalysts could be modified by tailoring the SMSI state through changing the crystal phase of the TiO
2
support and a corresponding thermal treatment strategy to enhance FTO performance.
Abstract Body‐temperature responsive shape memory polymers (SMPs) attract a lot of attention with the application in biomedicine. Multiple SMPs regulate the response temperature through the ...proportion of their stationary and reversible phases by changing the molecular weight of the polymer or the components of the composite. Herein, a crosslinking reaction of trans‐polyisoprene (TPI) and polycaprolactone (PCL) initiated by benzoyl peroxide gave a SMP of TPI/PCL, whose shape memory property is realized by stage‐division crystallization zone. Under the fixed ratio of TPI:PCL, the crystallization performance of TPI/PCL is controlled by the crosslinking density. The response temperatures of the components in TPI/PCL are selected for the stage‐division crystallization zone, making excellent shape memory performance at corresponding response temperatures. For the further achievement in controllable response temperature within a certain range, the relationship model between crosslinking density and response temperature is established, obtaining the customizable response temperature ranging 37–55 °C. The presented facile regulation method for response temperature will provide a new idea for the SMPs development.
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