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Based on the panel data of 257 prefecture-level cities in China from 2010 to 2017, this paper measured urban land green use efficiency (ULGUE), incorporating undesirable outputs, via the super efficiency slack-based model (SBM). It also explored the effect, mechanism, and heterogeneity of growth targets management and regional competition on ULGUE via the time-varying gravitational spatial weight matrix and the spatial self-lagging model. The results show that growth targets management and regional competition have significant positive effects on ULGUE, and enhance the ULGUE by promoting local investment attraction, increasing innovation inputs, optimizing environmental regulations and strengthening commercial activities. Additionally, growth targets management has a more significant effect on eastern cities, non-central cities, and mature urban agglomeration, while regional competition has a more significant effect on central cities, non-central cities, and developmental urban agglomeration. Therefore, considering development as the priority, setting relatively aggressive economic growth targets and optimizing the regional competition mechanism for growth targets management can help improve the ULGUE and promote high-quality economic development in China.
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Desarrollo Económico , Urbanización , China , Ciudades , EficienciaRESUMEN
With increasing constraints on resources and the environment, it is of great practical importance to discover and utilize the induced effect of green technology through market-based tools, in order to simultaneously realize economic development and ecological sustainability. Based on unique patent data from 1999 to 2013, this paper examines the induced effect of China's increasing-block electricity pricing scheme (IBP) on energy-efficient patents and checks whether the effect is neutral or biased. Furthermore, the quality of the induced patents is identified. The results reveal that increased green innovation is strongly related to the IBP scheme. In addition, the induced effect is biased towards green technology such that, apart from autonomous technological advances, the biased effect of IBP induced two more energy-efficient patents per hundred technological patents. However, the quality of the induced innovation is relatively low: compared to high-quality inventions, low-quality utility models showed greater and more significant growth due to the IBP. Our paper provides quantitative insight into the impact of the IBP and indicates that a reasonable pricing scheme can benefit both the environment and the economy.
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Desarrollo Económico , Invenciones , China , Costos y Análisis de Costo , TecnologíaRESUMEN
Novel composite photocatalysts BiOBr/Bi(C2O4)OH were successfully fabricated via a chemical etching method. After flower-like Bi(C2O4)OH microstructure assembled by nanorods was etched by KBr under an appropriate acidic condition, BiOBr nano-rods could be in-situ generated in nanorods, forming a heterostructure. The heterostructures exhibited a commendable photocatalytic performance toward the degradation of rhodamine B under the visible light irradiation. The effective separation and transfer of the photogenerated electrons and holes were believed to be the main factor for the enhanced activity, which resulted from the intrinsic characteristic of p-n junction. The responsible mechanism was detailedly discussed, and the photogenerated holes and O2- radicals were confirmed to be the main active species for the photodegradation of RhB.
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B-doped BiOBr photocatalysts were successfully synthesized via a facile solvothermal method with boric acid used as boron source. As-obtained products consist of novel hierarchical microspheres, whose nanosheet building units were formed by nanoparticles splicing. They showed dramatic photocatalytic efficiency toward the degradation of Rhodamine B (RhB) and phenol under the visible-light irradiation and the highest activity was achieved by 0.075B-BiOBr. The enhanced photocatalytic activity could be attributed to the enriched surface hydroxyl groups on B-doped BiOBr samples, which not only improved the adsorption of pollutant on the photocatalyst but also promoted the separation of photogenerated electron-hole pairs. In addition, it was found that the main reactive species responsible for the degradation of organic pollutant were h(+) and O2(-) radicals, instead of OH radicals.
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BiOBr/Bi24O31Br10 heterojunction photocatalysts were prepared by a facile solvothermal method for the first time. The X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), N2 sorption, UV-vis diffuse reflectance spectroscopy (UV-vis DRS) and photoluminescence (PL) were applied to investigate the structures, morphologies, surface areas and photocatalytic properties of as-prepared samples. The photocatalytic activity of the samples was evaluated by the photocatalytic degradation of Rhodamine B under the visible-light irradiation. The results showed that BiOBr/Bi24O31Br10 heterojunctions with the different Bi24O31Br10 contents could be obtained by simply adjusting the amount of NaOH solution, all of which exhibited enhanced photocatalytic activity compared with bare BiOBr or Bi24O31Br10. Among them, the BiOBr/Bi24O31Br10 heterojunction prepared with 1.5ml of NaOH solution possessed the highest photocatalytic activity. The photogenerated holes and ·O2(-) radicals were confirmed to be the main active species responsible for the photodegradation of RhB. The mechanism of enhanced photocatalytic activity was discussed and the transfer process of the photogenerated charges carrier between BiOBr and Bi24O31Br10 was proposed on the basis of the estimated energy band positions.
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Antibacterianos/química , Materiales Biocompatibles/química , Cerámica/química , Materiales Dentales/química , Geles/química , Povidona/química , Nitrato de Plata/química , Materiales Biocompatibles/metabolismo , Cerámica/metabolismo , Materiales Dentales/metabolismo , Durapatita/química , Geles/metabolismo , Calor , Humanos , Ensayo de Materiales , Fenómenos Mecánicos , Nanoestructuras/química , Porosidad , Povidona/metabolismo , Propiedades de SuperficieRESUMEN
Cadmium sulphide (CdS) quantum dots (QDs) sensitized that hierarchical bismuth oxybromide (BiOBr) photocatalysts were synthesized via a facile solvothermal approach for the first time, which were characterized by XRD, XPS, SEM, TEM, PL, and UV-vis DRS spectra. The photocatalytic activities were evaluated by the decomposition of methyl orange (MO) under visible light irradiation with commercial TiO(2) Degussa P25 as reference. The results revealed that CdS-BiOBr photocatalysts had strong light absorption in the visible light region compared with pure BiOBr. All CdS-BiOBr photocatalysts possessed higher photocatalytic activity than pure BiOBr and Degussa P25 under the visible light irradiation. The highest activity was obtained by 2%CdS-BiOBr. The enhanced photocatalytic performances were attributed to the matched band potentials of CdS QDs and BiOBr, which resulted in the efficient separation of photogenerated electron-hole pairs. Based on the experimental results, a reasonable photocatalytic mechanism over CdS-BiOBr photocatalysts was proposed. And the photodegradation of MO are associated with ()O(2)(-) radicals and the photogenerated holes on the valance bands of CdS QDs and BiOBr.