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With rapid economic development and urban expansion, China faces a serious imbalance between production, living, and ecological land use, in which the erosion of water ecological space by urban expansion is especially notable. In order to alleviate or solve this imbalance, this study constructs the water ecological space in the Mulan River Basin based on national land spatial planning using remote sensing statistics and the 2000–2020 statistical yearbooks for the Mulan River Basin. A landscape index is applied to explore this landscape in terms of its production–living–ecological space (PLES) patterns and evolutionary characteristics. Factors affecting the drivers of PLES changes are analyzed through Geo-Detector, and predictions are made using the cellular automata Markov (CA-Markov) model. It was found that (1) PLES distribution patterns in the Mulan River Basin from 2000 to 2020 are dominated by non-watershed ecological spaces, with a significant expansion of living space. Its ecological space is shrinking, and there is significant spatial variation between its near-river and fringe areas. (2) Of the PLES conversions, the most dramatic conversions are those of production space and living space, with 81.14 km2 of production space being transferred into living space. Non-water ecological space and water ecological space are also mainly transferred into production space. (3) As shown by the results of the landscape index calculation, non-water ecological space in the Mulan River Basin is the dominant landscape, the values of the Shannon diversity index (SHDI) and Shannon homogeneity index (SHEI) are small, the overall level of landscape diversity is low, the aggregation index (AI) is high, and the degree of aggregation is obvious. (4) The progressive PLES changes in the Mulan River Basin are influenced by a combination of natural geographic and socioeconomic factors, with the mean population density and mean elevation being the most important factors affecting PLES changes among social and natural factors, respectively. (5) The Kappa coefficient of the CA-Markov model simulation is 0.8187, showing a good simulation accuracy, and it is predicted that the area of water ecological space in the Mulan River Basin will increase by 3.66 km2 by 2030, the area of production space and non-water ecological space will further decrease, and the area of construction land will increase by 260.67 km2. Overall, the aquatic ecological space in the Mulan River Basin has made progress in terms of landscape ecological protection, though it still faces serious erosion. Therefore, attaching importance to the restoration of the water ecological space in the Mulan River Basin, integrating multiple elements of mountains, water, forests, fields, and lakes, optimizing the spatial structure of its PLES dynamics, and formulating a reasonable spatial planning policy are effective means of guaranteeing its ecological and economic sustainable development. This study offers recommendations for and scientific defenses of the logical design of PLES spatial functions in the Mulan River Basin. [ABSTRACT FROM AUTHOR]

The fracturing property of liquid CO2 fracturing fluid varies greatly due to the rheology of fracturing fluid during fracturing process. The main objective of this investigation is to study the rheology property of thickened liquid CO2 by measuring the viscosity of thickened liquid CO2 in different physical parameters of this prepared thickener and explain the causes of rheological changes. The results show that thickener content, branching content, and molecular weight of a thickener for all could significantly improve the rheology of liquid CO2; the consistency coefficient K increased as they rose, but the rheological index n presented a decreased trend. Meanwhile, the mesh structure is proposed as a model to explain the rheological changes, and the large wetting angle means an excellent backflow, low reservoir damage, and low adsorption property. These results herein provide a basic reference to improve the CO2 fracturing technology and molecular design of CO2 thickener. [ABSTRACT FROM AUTHOR]

As an important working fluid in tight shale reservoir, supercritical CO2 has been proven to improve oil recovery efficiently. However, the high filtration caused by the low viscosity of pure supercritical CO2 hinders its development. The research objective of this investigation is to explore the filtration of supercritical CO2 with a branched siloxane (BTMT) as a CO2 thickener and filtration-reducing agent, and analyze the influence level of some parameters about rock core and chemicals on the CO2 filtration in the tight shale reservoir by using response surface method (RSM). The results demonstrate that the rising temperature causes a gradually increasing filtration, but filtration coefficient (f) decreases with increasing the pressure difference P, injection speed, and thickener concentration. The thickener concentration is the factor that causes the greatest change in filtration coefficient according to the response surface method, and the injection speed has the smallest effect on the filtration. The viscosity of fracturing fluid is the main characterization parameter leading to change of filtration coefficient, all factors that contribute to increasing the viscosity of the fracturing fluid will lead to a reduction in the filtration coefficient and an enhanced oil recovery. In addition, the adsorption and reservoir residue of BTMT on low-permeability shale were subordinated to a Langmuir monolayer theory, and a low residual of BTMT in shale can prevent thickeners and fracturing fluids from damaging shale reservoirs. The improvement of thickener and CO2 fracturing technology provided a basic reference for shale exploitation, greenhouse effect, and reservoir protection. [ABSTRACT FROM AUTHOR]

A novel "dual isolation of metal active sites" heterojunction engineering is developed in this work. The double isolation of the active sites is achieved through MN4 (M = Co, Fe) coordinating bonds in sulfonated‐substituted metalloporphyrin (MTPPS) and electrostatic interactions of MTPPS absorbed with poly(3,4‐ethylenedioxythiophene) networks. Subsequent "in situ copyrolysis" over the precursors ensures effective contact between p‐type CoFe2O4 and n‐type Fe2O3 species with n‐type N,S‐doping carbon support, respectively. This leads to p–n CoFe2O4‐N,S‐C and n–n Fe2O3‐N,S‐C heterojunctions. Meanwhile, CoFe2O4‐N,S‐C has a higher EVB energy level (−6.22 eV) than Fe2O3‐N,S‐C (−6.31 eV), achieving lower energy barrier, and thus superior oxygen reduction reaction (ORR) performance with a higher half‐wave potential (0.84 V) of CoFe2O4‐N,S‐C than Fe2O3‐N,S‐C (0.82 V). In addition, CoFe2O4‐N,S‐C also exhibits higher oxygen evolution reaction (OER) performance with 100 mV lower overpotential (0.41 V) than Fe2O3‐N,S‐C. The lower overpotential is a result of larger energy gap between ECB energy level and Fermi level of CoFe2O4‐N,S‐C. This is the first demonstration of a novel p–n heterojunction with a special band structure that plays a key role in highly active ORR and OER bifunctional catalysis. Moreover, CoFe2O4‐N,S‐C displays significant photoelectrochemical enhancement upon light irradiation. [ABSTRACT FROM AUTHOR]