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双层组合桨气液搅拌槽流动与功耗特性的数值模拟
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作者 张梦瑶 肖亚峰 +5 位作者 董中天 马少萍 吴双 于明州 张庆华 杨超 《过程工程学报》 北大核心 2025年第7期695-705,共11页
以氯乙酸氨解法合成甘氨酸体系为研究对象,采用数值模拟方法研究了双层三窄叶旋桨式搅拌桨(ZCX-ZCX)、三窄叶旋桨式搅拌桨-抛物线型圆盘涡轮桨(ZCX-PDT)和三窄叶旋桨式搅拌桨-错位圆弧式抛物线型圆盘涡轮桨(ZCX-SFPDT)等三种双层组合桨... 以氯乙酸氨解法合成甘氨酸体系为研究对象,采用数值模拟方法研究了双层三窄叶旋桨式搅拌桨(ZCX-ZCX)、三窄叶旋桨式搅拌桨-抛物线型圆盘涡轮桨(ZCX-PDT)和三窄叶旋桨式搅拌桨-错位圆弧式抛物线型圆盘涡轮桨(ZCX-SFPDT)等三种双层组合桨气液两相搅拌槽流场和功耗特性,比较了三种组合桨搅拌槽中的速度分布、湍动能分布、气含率分布、气泡直径分布以及功耗。结果表明,与ZCX-ZCX组合桨相比,ZCX-PDT和ZCX-SFPDT双层桨搅拌槽内气体分散效果更好,ZCX-SFPDT组合桨搅拌槽内的流场分布最均匀,功率准数比ZCX-PDT降低6.1%,传质效率增加10.9%,更适合应用于气液搅拌槽。 展开更多
关键词 气液搅拌槽 流场 功率特性 数值模拟 双层桨
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Building a click model: From idea to practice
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作者 Chao Wang Yiqun Liu shaoping ma 《CAAI Transactions on Intelligence Technology》 2016年第4期313-322,共10页
Click-through information is considered as a valuable source of users' implicit relevance feedback. As user behavior is usually influenced by a number of factors such as position, presentation style and site reputati... Click-through information is considered as a valuable source of users' implicit relevance feedback. As user behavior is usually influenced by a number of factors such as position, presentation style and site reputation, researchers have proposed a variety of assumptions to generate a reasonable estimation of result relevance. Therefore, many click models have been proposed to describe how user click action happens and to predict click probability (and search result relevance). This work builds upon many years of existing efforts from THUIR labs, summarizes the most recent advances and provides a series of practical click models. In this paper, we give an introduction of how to build an effective click model. We use two click models as specific examples to introduce the general procedures of building a click model. We also introduce common evaluation metrics for the comparison of different click models. Some useful datasets and tools are also introduced to help readers better understand and implement existing click models. The goal of this survey is to bring together current efforts in the area, summarize the research performed so far and give a view on building click models for web search. 展开更多
关键词 Search engine User behavior analysis Click model
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User behavior modeling for better Web search ranking 被引量:1
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作者 Yiqun LIU Chao WANG +1 位作者 Min ZHANG shaoping ma 《Frontiers of Computer Science》 SCIE EI CSCD 2017年第6期923-936,共14页
Modem search engines record user interactions and use them to improve search quality. In particular, user click-through has been successfully used to improve click- through rate (CTR), Web search ranking, and query ... Modem search engines record user interactions and use them to improve search quality. In particular, user click-through has been successfully used to improve click- through rate (CTR), Web search ranking, and query rec- ommendations and suggestions. Although click-through logs can provide implicit feedback of users' click preferences, de- riving accurate absolute relevance judgments is difficult be- cause of the existence of click noises and behavior biases. Previous studies showed that user clicking behaviors are bi- ased toward many aspects such as "position" (user's attention decreases from top to bottom) and "trust" (Web site reputa- tions will affect user's judgment). To address these problems, researchers have proposed several behavior models (usually referred to as click models) to describe users? practical browsing behaviors and to obtain an unbiased estimation of result relevance. In this study, we review recent efforts to construct click models for better search ranking and propose a novel convolutional neural network architecture for build- ing click models. Compared to traditional click models, our model not only considers user behavior assumptions as input signals but also uses the content and context information of search engine result pages. In addition, our model uses pa- rameters from traditional click models to restrict the meaning of some outputs in our model's hidden layer. Experimental results show that the proposed model can achieve consider- able improvement over state-of-the-art click models based on the evaluation metric of click perplexity. 展开更多
关键词 user behavior click model Web search
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