30 research outputs found
Centralization or Decentralization of Environmental Governance—Evidence from China
No full textFrom the perspective of environmental federalism, we extracted the environmental intention words from the work reports of China’s central and provincial governments through data mining, and used the instrumental variable method to conduct empirical experiments concerning the dispute between centralization and decentralization of environmental governance in the Chinese context. The results suggest that a negative correlation exists between the intention of the central government’s environmental governance and the provincial environmental quality, whereas a positive correlation exists between the intention of the provincial government and the provincial environmental quality. Our interpretation is that environmental centralization, coupled with its political, economic, and cultural factors, has converted provincial governments into supporters of environmental pollution, and that the central government’s ongoing environmental protection inspection campaign has forced the provincial government to be somewhat effective. We propose establishing Chinese-style cooperative federalism in environmental authority and not only centralizing or decentralizing in one direction. New transition mechanisms for the central government’s authority should be implemented, such as the environmental protection inspection groups mechanism and the ecological gross domestic product based political tournament
Cloning of SoDXR and its role in monoterpenoids synthesis in Syringa oblata
Get PDFAbstract [Objective] The purpose of this study is to examine the role of the DXR gene, encoding 1-deoxy-
D-xylulose-5-phosphate reductoisomerase, in monoterpenoids synthesis in lilac (Syringa oblata), and
to provide genetic resources and theoretical basis for the molecular breeding of floral fragrance of lilac.
[Methods] Firstly, the SoDXR gene was cloned. Then, bioinformatics and subcellular localization analysis
were performed, and qRT-PCR was used to analyze the gene expression patterns in different floral development
stages and tissues. Finally, transient overexpression of SoDXR in the petals of snapdragon (Antirrhinum
majus) was detected. [Results] ORF of SoDXR was 1 425 bp, encoding 474 amino acids.
SoDXR protein contained the conserved domain of DXP_reductoisom, which had a similarity of up to 95%
with Osmanthus fragrans and Olea europaea. Subcellular localization analysis showed that the protein was
mainly located in the plastids, consistent with the software prediction. With flowering, the expression level
of SoDXR was increased and then decreased, with the highest expression in the initial opening stage.
SoDXR was differentially expressed in various tissues with the highest in petals and the lowest in stems.
Transient overexpression revealed that the expression of SoDXR was higher than the control. Moreover,
the main floral volatile components in snapdragon petals, myrcene and ocimene, were increased by 15.03
and 4.83 times, respectively. [Conclusion] The SoDXR gene positively regulates monoterpenoids synthesis
in lilac, and may play an important role in the synthesis of secondary metabolites of floral fragrance
D-Optimal Design for Rapid Assessment Model of CO₂ Flooding in High Water Cut Oil Reservoirs
No full textMost of major oilfields in China have reached high water cut stage, but still, they contribute to more than 70% of domestic oil production. How to extract more oil from mature oilfields has become a hot topic in petroleum engineering. Carbon dioxide flooding is a win-win strategy because it can enhance oil recovery and simultaneously reduce CO2 emissions into the atmosphere. In order to evaluate the potentials of CO2 flooding in high water cut oil reservoirs, various 3-D heterogeneous geological models were built based on Guan 104 fault block in Dagang Oilfield to perform reservoir simulations. The D-optimal design was applied to build and verify the Rapid Assessment Model of CO2 flooding in high water cut oil reservoirs. Five quantitative variables were considered, including average horizontal permeability, permeability variation coefficient, ratio of vertical to horizontal permeability, net thickness of formation and percentage of recoverable reserves by water flooding. The process of weighting emphasized the contributions of linear terms, quadratic terms and first-order interactions of five quantitative parameters to improved recovery factor and Net Present Value of CO2 flooding. Using the Rapid Assessment Model of CO2 flooding in high water cut oil reservoirs, significant first-order interactions were sorted out and type curves were established and analyzed for the evaluation of technical and economic efficiency of CO2 flooding in high water cut oil reservoirs. Aimed at oil reservoirs with the similar geological conditions and fluid properties as Guan 104 fault block, the Rapid Assessment Model and type curves of CO2 flooding in high water cut oil reservoirs can be applied to predict improved recovery factor and Net Present Value of water-alternating-CO2 flooding at different conditions of reservoir parameters and development parameter. The approach could serve as a guide for the application and spread of CO2-EOR projects
Effect of Polymer on Disproportionate Permeability Reduction to Gas and Water for Fractured Shales
No full textLarge volumes of fracturing fluid are required in shale slickwater fracs, and a considerable amount of polymer friction reducer would remain in microfractures if the polymer has not been broken before gas production. It is of major interest to evaluate the effect of polymer on water/gas flow behavior in the microfractures of shale reservoirs. We fabricated six shale fracture models with different fracture widths and set up a core flooding apparatus to conduct brine/gas-injection experiments before and after polymer treatment. A method by which to calculate the residual resistance factor for gas (Frr,gas) was defined. The experimental results illustrate that polymer can reduce the permeability to water more than to gas. In the first cycle of brine/gas injection experiments after polymer treatment, the residual resistance factor for brine (Frr,water) and Frr,gas exhibited power-law characteristics through their shear rate and superficial gas velocity, respectively. The Frr,water and Frr,gas tended to decrease as the fracture width grew. Surprisingly, polymer treatment does not impair gas flow in wider fractures, and may even improve it. The mechanisms responsible for disproportionate permeability reduction (DPR) in the fractured shales were proposed in this paper
Enhancing Rare Object Detection on Roadways Through Conditional Diffusion Models for Data Augmentation
No full textThe detection of rare objects within traffic environments is critically important for the safety and reliability of autonomous driving systems. However, the scarcity of sufficient data and the long-tail effect associated with rare objects pose significant challenges to their detection. To address this issue, this study introduces a Conditional Diffusion Model, the RareGenDiffuse Model, which generates images of rare objects by taking traffic background images and corresponding bounding box images as inputs. Based on diffusion models, the RareGenDiffuse Model enables control over the category and location of the generated rare objects by adjusting the bounding box images. Experimental results demonstrate that the proposed model offers the advantages of high clarity and controllability. Utilizing the generated rare object dataset significantly enhances the detection outcomes for rare objects. The methodology proposed in this study can effectively reduce the efforts required for data acquisition and labeling, presenting a valuable solution to the challenges of rare object detection in traffic scenarios.</p
Alkali-Surfactant-Polymer ASP Flooding Field Test Using Horizontal Wells: Design, Implementation and Evaluation
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