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稠油热采井13寸3套管受热分析及井口抬升控制措施
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作者 王强 高旸昭 +1 位作者 赵立珍 刘志祥 《石油石化物资采购》 2024年第6期16-18,共3页
稠油热采井作为石油工业中的关键技术,在重质油资源开发中扮演着不可替代的角色。然而,在注热过程中,井口抬升问题一直未得到有效控制。基于此,通过有限元模拟方法,系统性地研究了不同工况下套管的温度分布和变化趋势,以深入理解注热过... 稠油热采井作为石油工业中的关键技术,在重质油资源开发中扮演着不可替代的角色。然而,在注热过程中,井口抬升问题一直未得到有效控制。基于此,通过有限元模拟方法,系统性地研究了不同工况下套管的温度分布和变化趋势,以深入理解注热过程中13寸3套管的温度变化情况。模拟结果表明,注热过程中,9寸5套管可快速达到热源温度,而13寸3套管与水泥环(外)的温度则较慢趋于平衡。水泥环具有一定的隔热效果,因此13寸3套管的温度约低30℃。垂直方向上,13寸3套管的温度差异较小,而水平方向上,受热影响范围约为1.2m。隔热油管的隔热效果越好,13寸3套管的温度下降越明显。隔热油管散热超过200℃,13寸3套管胶结完全失效。该研究结论对稠油热采过程中的井口抬升控制有指导性意义。 展开更多
关键词 稠油 注热分析 温度场模拟 井口抬升
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Sentiment classification model for bullet screen based on self-attention mechanism 被引量:2
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作者 ZHAO Shuxu LIU Lijiao MA Qinjing 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2021年第4期479-488,共10页
With the development of short video industry,video and bullet screen have become important ways to spread public opinions.Public attitudes can be timely obtained through emotional analysis on bullet screen,which can a... With the development of short video industry,video and bullet screen have become important ways to spread public opinions.Public attitudes can be timely obtained through emotional analysis on bullet screen,which can also reduce difficulties in management of online public opinions.A convolutional neural network model based on multi-head attention is proposed to solve the problem of how to effectively model relations among words and identify key words in emotion classification tasks with short text contents and lack of complete context information.Firstly,encode word positions so that order information of input sequences can be used by the model.Secondly,use a multi-head attention mechanism to obtain semantic expressions in different subspaces,effectively capture internal relevance and enhance dependent relationships among words,as well as highlight emotional weights of key emotional words.Then a dilated convolution is used to increase the receptive field and extract more features.On this basis,the above multi-attention mechanism is combined with a convolutional neural network to model and analyze the seven emotional categories of bullet screens.Testing from perspectives of model and dataset,experimental results can validate effectiveness of our approach.Finally,emotions of bullet screens are visualized to provide data supports for hot event controls and other fields. 展开更多
关键词 bullet screen text sentiment classification self-attention mechanism visual analysis hot events control
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A mechanical model for the role of the neck linker during kinesin stepping and gating
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作者 WANG HaiYan HE ChenJuan 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2011年第12期2230-2236,共7页
In this paper, considering the different elastic properties in the attached head and the free head, we propose a physical model, in which the free head undergoes a diffusive search in an entropic spring potential form... In this paper, considering the different elastic properties in the attached head and the free head, we propose a physical model, in which the free head undergoes a diffusive search in an entropic spring potential formed by undocking the neck linker, and there are asymmetric conformational changes in the attached head formed by docking the neck linker to support the load force and bias the diffusive search to the forward direction. By performing the thermodynamic analysis, we obtain the free energy difference between forward and backward binding sites. And using the Fokker-Planck equation with two absorbing boundaries, we obtain the dependence of the ratio of forward to backward steps on the backward force. Also, within the Michaelis-Menten model, we investigate the dependence of the velocity-load relationship on the effective length of the junction between the two heads. The results show that our model can provide a physical understanding for the processive movement of kinesin. 展开更多
关键词 entropy spring KINESIN Fokker-Planck equation
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