Publications by authors named "Mengyue Ma"

Hydrochlorofluorocarbons (HCFCs) are transitional substitutes for chlorofluorocarbons (CFCs). However, they still have the capacity to be ozone-depleting substances (ODSs). Therefore, they are scheduled to be phased out in China by 2030 under the Montreal Protocol.

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Methane (CH) is the second most abundant greenhouse gas. China is the largest CH emitter in the world, with coal mine methane (CMM) being one of the main anthropogenic contributions. Thus, there is an urgent need for comprehensive estimates and strategies for reducing CMM emissions in China.

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1,1-Difluoroethane (HFC-152a) is a hydrofluorocarbon regulated by the Montreal Protocol, and its emissions in China are of concern as China will regulate HFC-152a in 2024. However, no observation-inferred top-down estimates were undertaken after 2017, and substantial gaps existed among previous estimates of China's HFC-152a emissions. Using the atmospheric observations and inverse modeling, this study reveals China's HFC-152a emissions of 9.

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Article Synopsis
  • The Montreal Protocol aimed to eliminate the use of ozone-depleting CCl globally by 2010, including in China.
  • Despite this, new measurements indicate that CCl emissions in eastern China were still occurring at an estimated rate of 7.6 gigagrams per year from 2021 to 2022.
  • The study links these emissions to specific industrial activities, particularly the manufacture of machinery and chemical products.
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Having the highest ozone-depleting potential among hydrochlorofluorocarbons (HCFCs), the production and consumption of HCFC-141b (1,1-dichloro-1-fluoroethane, CHCClF) are controlled by the Montreal Protocol. A renewed rise in global HCFC-141b emissions was found during 2017-2020; however, the latest changes in emissions across China are unclear for this period. This study used the FLEXible PARTicle dispersion model and the Bayesian framework to quantify HCFC-141b emissions based on atmospheric measurements from more sites across China than those used in previous studies.

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With the prevalence of COVID-19, wearing medical surgical masks has become a requisite measure to protect against the invasion of the virus. Therefore, a huge amount of discarded medical surgical masks will be produced, which will become a potential hazard to pollute the environment and endanger the health of organisms without our awareness. Herein, a green and cost-effective way for the reasonable disposal of waste masks becomes necessary.

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China has implemented main functional areas planning (MFAP) since 2010, which is essential for improving the efficiency of land space utilization and achieving sustainable urban development. Quantitative assessments of the urban development levels (UDLs) at the county level across China after the implementation of MFAP have not been well-documented. In this study, a unified indicator system was developed, and the UDLs of 2850 counties in China after MFAP implementation were evaluated.

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The composite cathode material of the conductive polymer polyaniline (PANI)-coated spinel structural LiNiMnO (LNMO) for high-voltage lithium-ion batteries has been successfully synthesized by an in situ chemical oxidation polymerization method. The electrode of the LNMO-PANI composite material shows superior rate capability and excellent cycling stability. A capacity of 123.

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Under photoredox catalysis conditions, the conventional electrophilic reactivity of ketimines is inverted to generate nucleophilic species. As a result, chemoselective cross-electrophile couplings between aldehydes and ketimines are achieved via umpolung reactivity of ketimines to furnish amino alcohols (44 examples with good to excellent yields). To illustrate the utility of the amino alcohol products, 1,2-dihydroindol-3-one-based fluorophores are easily synthesized using the coupling products.

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Light-mediated transformations with CO have recently attracted great attention, with the focus on CO incorporation into C-C double and triple bonds, organohalides and amines. Herein is demonstrated visible light -mediated umpolung imine reactivity capable of engaging CO to afford α-amino acid derivatives. By employing benzophenone ketimine derivatives, CO fixation by hydrocarboxylation of C=N double bonds is achieved.

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A novel carbanionic reactivity of imines mediated by photoredox catalysis is demonstrated. The umpolung imine reactivity is exemplified by proton abstraction from water as a key step in the reduction of benzophenone ketimines to amines (up to 98% yield). Deuterium is introduced into amines efficiently using DO as an inexpensive deuterium source (≥95% D ratio).

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Prussian blue (PB) with concave centers is synthesized successfully through a hydrothermal method with the assistance of acid. In this study, the role of the acid is investigated systematically by adjusting the reaction temperature and time, using different kinds and amounts of acid, and changing the amount of PVP surfactant added. It is found that the acid can not only trigger the chemical reaction to form cubic PB, but also act as an etching reagent to tailor the morphology.

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Carbonaceous materials are one of the most promising anode materials for sodium-ion batteries, because of their abundance, stability, and safe usage. However, the practical application of carbon materials is hindered by poor specific capacity and low initial Coulombic efficiency. The design of porous structure and doping with heteroatoms are two simple and effective methods to promote the sodium storage performance.

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