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Grass carp was an important economic fish for freshwater aquaculture. The exploring and utilization of high-quality grass carp germplasm resources were important for ensuring a domestic supply of high-quality aquatic protein. However, natural grass carp populations in China were facing severe threats because of the effects of frequent human activities, water environment damage, overfishing, etc. Against this background, high-quality grass carp germplasm resources were the foundation for the healthy and sustainable development of the grass carp aquaculture industry, so systematic collection, preservation, identification, evaluation, protection, and utilization of them carry great strategic importance. This paper summarizes major research results of grass carp in morphology, cytogenetics, molecular population genetics, etc. It not only introduced genetic improvement techniques such as gynogenesis, hybrid breeding, and polyploid breeding, but also discussed the existing research on the protection measures of grass carp germplasm resources. On this basis, the paper proposed new methods to improve the protection of grass carp germplasm and create improved varieties, which could provide high-quality resources for the sustainable development of the grass carp industry. [ABSTRACT FROM AUTHOR]

Largemouth bass (Micropterus salmoides, LB) is an important aquaculture and fishing species in the world. LB has been introduced into China since 1983, and its aquaculture production has increased year by year. The total yield of LB in China reached 802,486 tons in 2022, ranking seventh in China's freshwater fish aquaculture. However, the LB is facing threats such as degradation of germplasm resources and disease susceptibility due to limitations in the scale of introduction, coupled with the effects of high-density aquaculture, inbreeding, and species hybridization. This paper summarizes the current status of LB germplasm resources, variety genetic improvement, nutrition and fodder, aquaculture mode and diseases, and circulation and processing. This paper also provides recommendations on how to fully explore and utilize the existing germplasm resources of LB; culture new LB germplasm that combines excellent resistance and growth characteristics through innovations in breeding techniques; reduce the morbidity rate and improve the efficiency of cultured LB through the optimization of fodder formulations and innovation of aquaculture modes; and shift the processing of LB toward standardization, efficient nutrition and safety through the integration of high-tech and large-scale production. This paper provides a reference for the sustainable and healthy development of the LB industry. [ABSTRACT FROM AUTHOR]

Urban underground space (UUS) development has been acknowledged as a positive contribution to urban resilience (UR). Such contribution has been qualitatively addressed in recent years, but only quantitatively discussed in few studies. Quantitative evaluation methods for UR are widely used in China and around the world, but the role of underground space is barely included. This paper provides a way to bridge this gap on the city scale. A UR evaluation framework was carefully constructed that covers the basic aspects and elements of UR. The contributions of UUS to UR were identified and integrated into the UR evaluation framework, and the measurement methods for each indicator related to UUS were determined. A case study of 19 sample cities in China were conducted using the integrated evaluation model. Correlation analysis and clustering analysis were further adopted to interpret the evaluation results, mainly with three indicators reflecting the level of UUS development, namely UUS area (m²), UUS density (104 m² /km² ) and UUS area per capita (m² / person). The results showed a strong correlation between UUS area and UR. The average proportion of UR provided by UUS in the 19 sample cities was 16.46%, while the maximum figure reached 29.20%. The sample cities were clustered into four categories based on the relationship between the proportion of UR provided by UUS, UUS area, and GDP per capita, where both high and low UUS area tend to provide less proportion of resilience than the medium UUS area. Corresponding suggestions for UUS utilization were proposed to assist cities in achieving urban resilience. [ABSTRACT FROM AUTHOR]

CO2 capture from coal power plants is an important and necessary solution to realizing carbon neutrality in China, but CCS demonstration deployment in power sector is far behind expectations. Hence, the reduction potential of energy consumption and cost for CCS and its competitiveness to renewable powers are very important to make roadmaps and policies toward carbon neutrality. Unlike the popular recognition that capturing CO2 from flue gases is technically and commercially mature, this paper notes that it has been proved to be technically feasible but far beyond technology maturity and high energy penalty leads to its immaturity and therefore causes high cost. Additionally, the potential energy penalty reduction of capture is investigated thermodynamically, and future CO2 avoidance cost is predicted and compared to renewable power (solar PV and onshore wind power). Results show that energy penalty for CO2 capture can be reduced by 48%-57%. When installation capacity reaches a similar scale to that of solar PV in China (250 GW), CO2 capture cost in coal power plants can be reduced from the current 28-40 US$/ton to 10-20 US$/ton, and efficiency upgrade contributes to 67%-75% in cost reduction for high coal price conditions. In China, CO2 capture in coal power plants can be cost competitive with solar PV and onshore wind power. But it is worth noting that the importance and share of CCS role in CO2 emission reduction is decreasing since renewable power is already well deployed and there is still a lack of large-scale CO2 capture demonstrations in China. Innovative capture technologies with low energy penalties need to be developed to promote CCS. Results in this work can provide informative references for making roadmaps and policies regarding CO2 emission reductions that contribute towards carbon neutrality. [ABSTRACT FROM AUTHOR]

Cooperation among enterprises can bring overall and individual performance improvement, and a smooth coordination method is indispensable. However, due to the lack of customized coordination methods, cooperation in the downstream oil supply chain cannot be carried out smoothly. This paper intends to propose a multi-party coordination method to promote cooperation between oil shippers and pipeline operator by optimizing oil transportation, oil substitution and pipeline pricing schemes. An integrated game-theoretic modeling and analysis approach is developed to characterize the operation behaviors of all stakeholders in the downstream oil supply chain. The proposed mixed integer nonlinear programming model constrains supply and demand capacity, transportation routes, oil substitution rules and pipeline freight levels. Logarithm transformation and price discretization are introduced for model linear approximation. Simulation experiments are carried out in the oil distribution system in South China. The results show that compared to the business-as-usual scheme, the new scheme saves transportation cost by 3.48%, increases pipeline turnover by 5.7%, and reduces energy consumption and emissions by 7.66% and 6.77%. It is proved that the proposed method improves the revenue of the whole system, achieves fair revenue distribution, and also improves the energy and environmental benefits of the oil supply chain. [ABSTRACT FROM AUTHOR]

Oil-gas two phase wax deposition is a fairly common and open-ended question in flow assurance of multiphase transportation pipelines. This paper investigated the two main aspects of oil-gas two phase wax deposition layer: apparent thickness and crystal structure characteristics. A typical highly paraffinic oil in Bohai Sea, China, was used as the experimental material to investigate the wax deposition thickness in oil-gas two phase under the influence of different oil temperatures, superficial gas/liquid phase velocities and gas-oil ratios by using multiphase flow loop experimental device. Just as in the classical theory of wax molecular diffusion, it showed that wax deposition thickness of oil-gas two phase increased with increasing oil temperature. Analysis of the impact of different superficial phase velocities found that the actual liquid flow heat transfer and shear stripping was the gas phase dominant mechanisms determining wax deposit thickness. In addition, the crystal structure of the wax deposition layer was characterized with the help of small-angle X-ray scattering (SAXS) for different circumferential positions, flow rates and gas-oil ratios. The bottom deposition layer had a complex crystal structure and high hardness, which were subject to change over flow rate variations. Furthermore, the SAXS results provided evidence that the indirect effect of the actual liquid velocity modified by the gas phase was the main mechanism. Our study of the effect of gas phase on the wax deposition of oil-gas two phase will help shed light onto the mechanism by which this important process occurs. Our findings address a very urgent need in the field of wax deposition of highly paraffinic oil to understand the flow security of oilgas two phase that occurs easily in multiphase field pipelines. [ABSTRACT FROM AUTHOR]

Lamellar calcite veins are prevalent in carbonate-rich, lacustrine dark shale. The formation mechanisms of these veins have been extensively debated, focusing on factors such as timing, depth, material source, and driving forces. This paper examines dark lacustrine shale lamellar calcite veins in the Paleogene strata of Dongying Depression, using various analytical techniques: petrography, isotope geochemistry, cathodoluminescence, inclusion thermometry, and electron probe micro-analysis. Two distinct types of calcite veins have been identified: granular calcite veins and sparry calcite veins. These two types differ significantly in color, grain structure, morphology, and inclusions. Through further investigation, it was observed that vein generation occurred from the shallow burial period to the maturation of organic matter, with a transition from granular calcite veins to sparry calcite veins. The granular calcite veins exhibit characteristics associated with the shallow burial period, including plastically deformed laminae and veins, the development of strawberry pyrite, the absence of oil and gas, weak fractionation in oxygen isotopes, and their contact relationship with sparry calcite veins. These granular calcite veins were likely influenced by the reduction of sulfate bacteria. On the other hand, sparry calcite veins with fibrous grains are antitaxial and closely linked to the evolution and maturation of organic matter. They contain oil and gas inclusions and show a distribution range of homogenization temperature between 90 °C and 120 °C and strong fractionation in oxygen isotopes, indicating formation during the hydrocarbon expulsion period. The carbon isotope analysis of the surrounding rocks and veins suggests that the material for vein formation originates from the shale itself, specifically authigenic micritic calcite modified by the action of methanogens. The opening of horizontal fractures and vein formation is likely driven by fluid overpressure resulting from undercompaction and hydrocarbon expulsion. Veins may form rapidly or through multi-stage composite processes. Early veins are predominantly formed in situ, while late veins are a result of continuous fluid migration and convergence. Furthermore, the veins continue to undergo modification even after formation. This study emphasizes that the formation of lamellar calcite veins in shale is a complex diagenetic process influenced by multiple factors: biology, organic matter, and inorganic processes, all operating at various stages throughout the shale's diagenetic history. [ABSTRACT FROM AUTHOR]

Freshwater aquaculture plays an important role in the global aquaculture industry. The success of freshwater aquaculture relies on the integration of bio-ecological remediation technologies to ensure its sustainable development. This paper systematically reviews the global literatures on bio-ecological remediation of freshwater aquaculture environments from 1990 to 2021, and discusses in detail the research progress and status quo in this field using both bibliometric analysis and content analysis. Our results indicate that the number of publications per year has increased year by year, with a particularly rapid increase after 2015. Institutions and researchers from China and the USA publish the greatest number of papers and contribute the most to this field. By analyzing the research progress in this field, we also find that the protection and restoration of freshwater aquaculture environments has received attention since as early as 1990, such as the application of constructed wetlands and recirculating aquaculture systems. Recently, researchers have increasingly focused on the use of microbial communities in remediation. Furthermore, vanRijn, J's papers are of great value to the research in this field. In content analysis, the application of primary technologies, including plant selection, aquatic animals, microorganisms, and biological filtration and purification equipment, as well as ecological engineering technologies with combinations of various types of organisms, is described to improve the effectiveness and efficiency of remediation. The performance, advantages, disadvantages, or limitations and prospects of these technology applications are analyzed in detail. By comparison, ecological engineering is shown to be the best remediation technology, being most comprehensive, and well-established. Taken together, this paper composes and summarizes existing work in this field, and provides guidance for future research on the improvement of existing technologies and the development of new technologies, with the aim of enhancing remediation capability, improving ecological sustainability and ensuring economic viability. [ABSTRACT FROM AUTHOR]

With the implementation of the Belt and Road Initiative, China is deepening its cooperation in oil and gas resources with countries along the Initiative. In order to better mitigate risks and enhance the safety of investments, it is of significant importance to research the oil and gas investment environment in these countries for China's overseas investment macro-layout. This paper proposes an indicator system including 27 indicators from 6 dimensions. On this basis, game theory models combined with global entropy method and analytic hierarchy process are applied to determine the combined weights, and the TOPSIS-GRA model is utilized to assess the risks of oil and gas investment in 76 countries along the Initiative from 2014 to 2021. Finally, the GM (1,1) model is employed to predict risk values for 2022 e2025. In conclusion, oil and gas resources and political factors have the greatest impact on investment environment risk, and 12 countries with greater investment potential are selected through cluster analysis in conjunction with the predicted results. The research findings may provide scientific decisionmaking recommendations for the Chinese government and oil enterprises to strengthen oil and gas investment cooperation with countries along the Belt and Road Initiative. [ABSTRACT FROM AUTHOR]

The analysis of interwell connectivity plays an important role in the formulation of oilfield development plans and the description of residual oil distribution. In fact, sandstone reservoirs in China's onshore oilfields generally have the characteristics of thin and many layers, so multi-layer joint production is usually adopted. It remains a challenge to ensure the accuracy of splitting and dynamic connectivity in each layer of the injection-production wells with limited field data. The three-dimensional well pattern of multi-layer reservoir and the relationship between injection-production wells can be equivalent to a directional heterogeneous graph. In this paper, an improved graph neural network is proposed to construct an interacting process mimics the real interwell flow regularity. In detail, this method is used to split injection and production rates by combining permeability, porosity and effective thickness, and to invert the dynamic connectivity in each layer of the injection-production wells by attention mechanism. Based on the material balance and physical information, the overall connectivity from the injection wells, through the water injection layers to the production layers and the output of final production wells is established. Meanwhile, the change of well pattern caused by perforation, plugging and switching of wells at different times is achieved by updated graph structure in spatial and temporal ways. The effectiveness of the method is verified by a combination of reservoir numerical simulation examples and field example. The method corresponds to the actual situation of the reservoir, has wide adaptability and low cost, has good practical value, and provides a reference for adjusting the injection-production relationship of the reservoir and the development of the remaining oil. [ABSTRACT FROM AUTHOR]

This paper attempts to explore the decoupling relationship and its drivers between industrial economic increase and energy-related CO2 emissions (ICE). Firstly, the decoupling relationship was evaluated by Tapio index. Then, based on the DEA meta-frontier theory framework which taking into account the regional and industrial heterogeneity and index decomposition method, the driving factors of decoupling process were explored mainly from the view of technology and efficiency. The results show that during 2000e2019, weak decoupling was the primary state. Investment scale expansion was the largest reason hindering decoupling process of industrial increase from ICE. Both energy saving and production technology achieved significant progress, which facilitated the decoupling process. Simultaneously, the energy technology gap and production technology gap among regions have been narrowed, and played a role in promoting decoupling process. On the contrary, both scale economy efficiency and pure technical efficiency have inhibiting effects on decoupling process. The former indicates that the scale economy of China's industry was not conducive to improve energy efficiency and production efficiency, while the latter indicates that resource misallocation problem may exist in both energy market and product market. [ABSTRACT FROM AUTHOR]

Due to the considerable depth of the salt layers and the lack of calibration by exploratory drilling, the interpretation of the Middle and Lower Cambrian salt formations in the central Tarim Basin poses a challenge. In this paper, we apply the coupling and decoupling deformation theory in salt tectonics to analyze the No.7 fault mapped in the seismic datasets by the response characteristics of the Middle and Lower Cambrian layers. By quantifying the stratigraphic framework of the Middle and Lower Cambrian strata, we define the position of the salt layer with the seismic data. Structural decoupling is observed in the Middle and Lower Cambrian sequences in the Shuntuoguole Low Uplift, while deformation coupling is observed in these two sequences in the Shaya Uplift. [ABSTRACT FROM AUTHOR]

Financial incentives play a key role in promoting renewable energy investments that can help China achieve the 'dual carbon' goal. The national emissions trading scheme (ETS) and the renewable energy portfolio standard (RPS) are two existing market-based policy instruments that can generate stable expected returns for low-carbon projects. This paper studies the interactive distribution effects of these two market-based instruments. We use the micro-level thermal power plant data to investigate the abatement effects of the national ETS, in which the details show that the existing rate-based ETS will result in higher negative impacts on power units, whose installed capacities are smaller than 400 MW. The interactive distribution effects between the two markets will occur when the permit allocation standards of the national ETS become stricter than the existing ones. Provinces in Eastern China and Northern China will face high pressure on costs in both ETS and RPS markets. When the levels of the permit allocation standards are set as 70% of the existing ones and the carbon price is assumed to be 200 yuan/ton in 2030, the annual market size of the national ETS will be nearly 100 billion yuan, and the annual market size is predicted to be 250 billion yuan. In the existing rate-based national ETS, the China Certified Emission Reduction (CCER) mechanism will have an offsetting effect, which should be taken into serious consideration during the policy-making processes in the future. [ABSTRACT FROM AUTHOR]

China has been the top aquaculture producer in the world since 2002. Over 800 species and 240 improved varieties have been used in China's aquaculture, which is the most diverse collection of species on this planet. Species diversification, along with other aquaculture technologies, contributes significantly to the increase of China's aquaculture production, whereas the use of too many species in aquaculture has resulted in some issues related to the environment and sustainability. We provide an updated overview of the species currently used in Chinese aquaculture in this paper. We examine critically the main drivers of species diversification in China with examples. We also introduce Chinese approaches to improve and certify new species and varieties for commercial production. We believe that further species diversification is not a priority in China's aquaculture, while further improvement of aquaculture technologies for major and native species is essential for green, profitable, and sustainable (GPS) aquaculture. The implications of China's experiences with species diversification for global aquaculture species diversification are discussed. [ABSTRACT FROM AUTHOR]

Guizhou Province of China is rich in shale gas resources. In recent years, important progress has been made in the exploration and development of shale gas in the Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation in Zheng'an block in northern Guizhou, adjacent to Sichuan Basin. Due to the complex geological conditions and fragile ecological environment in the shale gas distribution area, serious environmental pollution risks may exist in shale gas exploitation. Therefore, this paper conducted element, hydrogen and oxygen isotope analyses for shale gas fracturing flowback/produced water of Well AY7-4 in Zheng'an block. The results showed that the contents of K, Na, Ca, Mg and NH+ 4 in the flowback/produced water of Well AY7-4 were very high, with an average of 118 mg/L, 7616 mg/L, 266 mg/L, 47 mg/L and 76 mg/L, respectively. The content of Na, Ca and Mg is similar to that of shale gas flowback/produced water in Weiyuan, but lower than that in Changning and Fuling. NH+ 4 content was similar to that in Changning, but much higher than that in Weiyuan. The average Cl content was 11605 mg/L, which was similar to that in Weiyuan, but lower than that in Changning and Fuling. The average Br content is 48 mg/L, slightly lower than that of Weiyuan, and about half of that of Changning and Fuling. Correspondingly, the Br/Cl value of Well AY7-4 is the lowest, reflecting its relatively low Br content. The average content of Li, B and Sr is 17 mg/L, 10 mg/L and 45 mg/L, respectively, which is similar to that of the Weiyuan, Changning and Fuling shale gas fields. The distribution model of Li and Sr is similar to that of Cl, Br and Na, but the B content and B/Cl value of Well AY7-4 are the lowest. The linear relationship between Br and Cl contents and between dD and d18O of flowback/produced water of Well AY7-4, freshwater used for hydraulic fracturing and hydraulic fracturing injected fluid indicates that flowback/produced water of Well AY7-4 is mainly the mixed product between low salinity injected fracturing fluid and high salinity brine retained in shale formation. The hydrogen and oxygen isotopic compositions gradually become heavier over time, indicating that the proportion of high salt end formation brine in flowback/produced water is increasing. The contents of Cl, Br, Na and NH+ 4 in the flowback/produced water of Well AY7-4 are far higher than the allowable discharge value, which is a potential environmental pollution risk and cannot be discharged directly. [ABSTRACT FROM AUTHOR]

Guizhou Province of China is rich in shale gas resources. In recent years, important progress has been made in the exploration and development of shale gas in the Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation in Zheng'an block in northern Guizhou, adjacent to Sichuan Basin. Due to the complex geological conditions and fragile ecological environment in the shale gas distribution area, serious environmental pollution risks may exist in shale gas exploitation. Therefore, this paper conducted element, hydrogen and oxygen isotope analyses for shale gas fracturing flowback/produced water of Well AY7-4 in Zheng'an block. The results showed that the contents of K, Na, Ca, Mg and NH+ 4 in the flowback/produced water of Well AY7-4 were very high, with an average of 118 mg/L, 7616 mg/L, 266 mg/L, 47 mg/L and 76 mg/L, respectively. The content of Na, Ca and Mg is similar to that of shale gas flowback/produced water in Weiyuan, but lower than that in Changning and Fuling. NH+ 4 content was similar to that in Changning, but much higher than that in Weiyuan. The average Cl content was 11605 mg/L, which was similar to that in Weiyuan, but lower than that in Changning and Fuling. The average Br content is 48 mg/L, slightly lower than that of Weiyuan, and about half of that of Changning and Fuling. Correspondingly, the Br/Cl value of Well AY7-4 is the lowest, reflecting its relatively low Br content. The average content of Li, B and Sr is 17 mg/L, 10 mg/L and 45 mg/L, respectively, which is similar to that of the Weiyuan, Changning and Fuling shale gas fields. The distribution model of Li and Sr is similar to that of Cl, Br and Na, but the B content and B/Cl value of Well AY7-4 are the lowest. The linear relationship between Br and Cl contents and between dD and d18O of flowback/produced water of Well AY7-4, freshwater used for hydraulic fracturing and hydraulic fracturing injected fluid indicates that flowback/produced water of Well AY7-4 is mainly the mixed product between low salinity injected fracturing fluid and high salinity brine retained in shale formation. The hydrogen and oxygen isotopic compositions gradually become heavier over time, indicating that the proportion of high salt end formation brine in flowback/produced water is increasing. The contents of Cl, Br, Na and NH+ 4 in the flowback/produced water of Well AY7-4 are far higher than the allowable discharge value, which is a potential environmental pollution risk and cannot be discharged directly. [ABSTRACT FROM AUTHOR]