10 research outputs found

    FSUIE: A Novel Fuzzy Span Mechanism for Universal Information Extraction

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    Universal Information Extraction (UIE) has been introduced as a unified framework for various Information Extraction (IE) tasks and has achieved widespread success. Despite this, UIE models have limitations. For example, they rely heavily on span boundaries in the data during training, which does not reflect the reality of span annotation challenges. Slight adjustments to positions can also meet requirements. Additionally, UIE models lack attention to the limited span length feature in IE. To address these deficiencies, we propose the Fuzzy Span Universal Information Extraction (FSUIE) framework. Specifically, our contribution consists of two concepts: fuzzy span loss and fuzzy span attention. Our experimental results on a series of main IE tasks show significant improvement compared to the baseline, especially in terms of fast convergence and strong performance with small amounts of data and training epochs. These results demonstrate the effectiveness and generalization of FSUIE in different tasks, settings, and scenarios.Comment: ACL202

    A calculation model for the head-on resistance of rock pipe jacking based on the rock breaking characteristics of the disc cutter

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    Jacking force is one of the most important parameters in the design and construction of pipe jacking. The accuracy of the jacking force will directly affect the success or failure of the pipe jacking project. Pipe jacking is increasingly applied to rock formations, but there are few calculation models for the jacking force in rock formations. To calculate the head-on resistance in the rock formation more accurately, a new calculation formula of the construction face resistance during pipe jacking is derived. The pipe jacking face is assumed to be stable; the rock pipe jacking force is analyzed by consideration of the rock breaking mechanism, force model and influence law of the rock pipe jacking machine cutter head hob. The results show that in rock pipe jacking, the compressive and shear strengths of the rock and the depth of the pipe jacking hob cut into the rock directly determine the value of the head-on resistance; after determining the appropriate hob spacing, the number of tools is not blindly increased; otherwise, the rock breaking effect of each hob will be affected. Moreover, the measured head-on resistance in engineering practice is consistent with the predicted value of the formula, which proves its applicability

    A Segmented Calculation Method for Friction Force in Long-Distance Box Jacking Considering the Effect of Lubricant

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    In box jacking, injecting lubricant around the box is an essential method to reduce excessive friction forces caused by the interaction between the box and soil. This method introduces complexity to factors controlling the friction forces, such as the pipe-soil contact state, earth pressure, and friction coefficient. In particular, during long-distance construction, different lubricant conditions come into play. These intricate scenarios hinder the accurate estimation and control of friction force throughout the entire construction period. This study analyzed the variation patterns of frictional resistance based on monitoring data from two actual cases. The lubricant condition changes during the long-distance jacking process were categorized, the effect of lubricant actions on factors controlling friction force in each segment was discussed, and a new method for calculating friction forces by partitioning the long-distance box jacking was proposed. This approach aims to enhance the prediction accuracy and was compared with the results obtained from existing models. The rationality of the new model was further validated by combining numerical simulation results with field data. The results indicate that the proposed segmented calculation model demonstrates better prediction accuracy when facing variations in actual construction conditions. It can serve as a reference for the process design and construction control of long-distance box jacking

    Key Techniques for Rapid Jacking and Laying of Pipelines: A Case Study on ‘Jingshihan’ Gas Pipelines in China

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    With the rapid growth of the oil and gas storage, transportation, and pipeline industries, it is necessary to improve the construction process of oil and gas pipelines. By combining the technical advantages of horizontal directional drilling and pipe jacking construction, the direct pipe laying method is suitable for pipeline crossing in different strata in the oil and gas, water conservancy and hydropower, and municipal industries due to its advantages of less construction land, high speed, and reversibility. Using the rapid jacking and laying of pipelines crossing Nanjuma River in the ‘Jingshihan’ gas pipeline double line project as a case study, this paper investigates the application status of the direct pipe laying method, summarizes the project, and introduces the construction of the working well, equipment selection, guiding control technology, supporting equipment installation, and drag reduction measures, as well as analyzes the influencing factors of thrust force and trajectory deviation combined with formation information

    Key Techniques for Rapid Jacking and Laying of Pipelines: A Case Study on ‘Jingshihan’ Gas Pipelines in China

    No full text
    With the rapid growth of the oil and gas storage, transportation, and pipeline industries, it is necessary to improve the construction process of oil and gas pipelines. By combining the technical advantages of horizontal directional drilling and pipe jacking construction, the direct pipe laying method is suitable for pipeline crossing in different strata in the oil and gas, water conservancy and hydropower, and municipal industries due to its advantages of less construction land, high speed, and reversibility. Using the rapid jacking and laying of pipelines crossing Nanjuma River in the ‘Jingshihan’ gas pipeline double line project as a case study, this paper investigates the application status of the direct pipe laying method, summarizes the project, and introduces the construction of the working well, equipment selection, guiding control technology, supporting equipment installation, and drag reduction measures, as well as analyzes the influencing factors of thrust force and trajectory deviation combined with formation information

    Properties of Lightweight Controlled Low-Strength Materials Using Construction Waste and EPS for Oil and Gas Pipelines

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    Due to its particularity and importance, long-distance oil and gas pipelines need to be well protected from damage by backfill materials. In this study, construction waste and expanded polystyrene (EPS) were used to replace conventional fine aggregate, and ethylene vinyl acetate-resin (EVA) was used to modify the surface of EPS to prepare lightweight controlled low strength materials (CLSM). Lightweight CLSM was tested in mechanics and physics and its microstructure was studied using microscopic analysis methods. The results revealed that the surface modification of EPS by EVA could greatly improve the compatibility of EPS with inorganic cementitious materials and prepare CLSM with a fluidity greater than 200 mm. EPS and cement content in cementitious materials play an important role in the development of material strength. When the volume ratio of EPS to construction waste was 2, and the content of cement in the cementitious materials was 35%, CLSM’s unconfined compressive strength at 28 days was only 0.48 MPa. In order to obtain the lightweight CLSM that meets the mechanical properties, the EPS content should not be too large. It can be concluded from the microscopic analysis that the increase of EPS content will lead to poor pore uniformity of the specimen, forming a loose mesh structure of defects, which is not conducive to the development of strength. In this study, EPS and construction waste are used to provide a green idea for preparing lightweight controlled low strength materials, which provides a reference for the backfill protection of the material in oil and gas pipelines in the future

    Properties of Lightweight Controlled Low-Strength Materials Using Construction Waste and EPS for Oil and Gas Pipelines

    No full text
    Due to its particularity and importance, long-distance oil and gas pipelines need to be well protected from damage by backfill materials. In this study, construction waste and expanded polystyrene (EPS) were used to replace conventional fine aggregate, and ethylene vinyl acetate-resin (EVA) was used to modify the surface of EPS to prepare lightweight controlled low strength materials (CLSM). Lightweight CLSM was tested in mechanics and physics and its microstructure was studied using microscopic analysis methods. The results revealed that the surface modification of EPS by EVA could greatly improve the compatibility of EPS with inorganic cementitious materials and prepare CLSM with a fluidity greater than 200 mm. EPS and cement content in cementitious materials play an important role in the development of material strength. When the volume ratio of EPS to construction waste was 2, and the content of cement in the cementitious materials was 35%, CLSM’s unconfined compressive strength at 28 days was only 0.48 MPa. In order to obtain the lightweight CLSM that meets the mechanical properties, the EPS content should not be too large. It can be concluded from the microscopic analysis that the increase of EPS content will lead to poor pore uniformity of the specimen, forming a loose mesh structure of defects, which is not conducive to the development of strength. In this study, EPS and construction waste are used to provide a green idea for preparing lightweight controlled low strength materials, which provides a reference for the backfill protection of the material in oil and gas pipelines in the future

    Integrating a ferroelectric interface with a well-tuned electronic structure in lithium-rich layered oxide cathodes for enhanced lithium storage

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    Li-rich layered oxides (LLOs) are considered promising candidates for new high-energy-density cathode materials for next-generation power batteries. However, their large-scale applications are largely hindered by irreversible Li/O loss, structural degradation, and interfacial side reactions during cycling. Herein, we demonstrate an integration strategy that tunes the electronic structure by La/Al codoping and constructs a ferroelectric interface on the LLOs surface through Bi0.5Na0.5TiO3 (BNT) coating. Experimental characterization reveals that the synergistic effect of the ferroelectric interface and the well-tuned electronic structure can not only promote the diffusion of Li+ and hinder the migration of On– but also suppress the lattice volume changes and reduce interfacial side reactions at high voltages up to 4.9 V vs Li+/Li. As a result, the modified material shows enhanced initial capacities and retention rates of 224.4 mAh g–1 and 78.57% after 500 cycles at 2.0–4.65 V and 231.7 mAh g–1 and 85.76% after 200 cycles at 2.0–4.9 V at 1C, respectively
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