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Numerical simulation of the 3D flow field in a ring die pellet mill considering viscous heating

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International Journal of Modeling, Simulation, and Scientific Computing 2020年第3期11卷 135-153页

作者： Yong-Mei wang xiao-Peng Huang Jin-Feng Wu wan-xia yang College of Mechanical and Electrical Engineering Gansu Agricultural University Lanzhou 730070P.R.China

Viscous heating has a substantial influence on the extrusion forming process and product quality of powder *** study selected the MUZL420 ring die pellet mill as the research object,from which a 3D flow physical model was *** numerical simulation of 3D nonisothermal flow in the extrusion pelletizing process of granulated alfalfa was performed with *** distribution laws of pressure,velocity,shear rate,viscosity,viscous heating and temperature in the flow field were revealed to thoroughly investigate the pelletizing process and provide a reference for structural optimization and process *** results showed that two extrusion zones in the pelleting chamber were symmetrical with respect to the center,and the significant pressure gradient along the rotating direction of the ring die and the roller caused the material to flow back in the opposite *** were larger velocity gradients,shear rates and viscous heating levels in the deformation and compaction zone,the negative pressure zone behind the extrusion zone and the die *** distribution of viscosity was opposite to that of the shear *** temperature increase area caused by viscous heating gradually expanded from the material inlet to the bottom of the extrusion chamber along the Z-axis direction,and the temperature increased *** extrusion force and the forming temperature in the extrusion forming zone were captured in the numerical *** extrusion forming density was calculated with the regression prediction model established through the simulation experiment of pelletizing with a ring *** a comparison with the results of mean alfalfa pellet density from the ring die pellet mill experiment,the relative error was less than 5%,which indicated that the numerical simulation method was reliable.

关键词： Ring die pellet mill viscous heating 3D flow field numerical simulation

Construction and evaluation of a liver cancer risk prediction model based on machine learning

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World Journal of Gastrointestinal Oncology 2024年第9期16卷 3839-3850页

作者： Ying-Ying wang wan-xia yang Qia-Jun Du Zhen-Hua Liu Ming-Hua Lu Chong-Ge You Laboratory Medicine Center The Second Hospital&Clinical Medical SchoolLanzhou UniversityLanzhou 730030Gansu ProvinceChina

BACKGROUND Liver cancer is one of the most prevalent malignant tumors worldwide,and its early detection and treatment are crucial for enhancing patient survival rates and quality of ***,the early symptoms of liver cancer are often not obvious,resulting in a late-stage diagnosis in many patients,which significantly reduces the effectiveness of *** a highly targeted,widely applicable,and practical risk prediction model for liver cancer is crucial for enhancing the early diagnosis and long-term survival rates among affected *** To develop a liver cancer risk prediction model by employing machine learning techniques,and subsequently assess its *** In this study,a total of 550 patients were enrolled,with 190 hepatocellular carcinoma(HCC)and 195 cirrhosis patients serving as the training cohort,and 83 HCC and 82 cirrhosis patients forming the validation *** regression(LR),support vector machine(SVM),random forest(RF),and least absolute shrinkage and selection operator(LASSO)regression models were developed in the training *** performance was assessed in the validation ***,this study conducted a comparative evaluation of the diagnostic efficacy between the ASAP model and the model developed in this study using receiver operating characteristic curve,calibration curve,and decision curve analysis(DCA)to determine the optimal predictive model for assessing liver cancer *** Six variables including age,white blood cell,red blood cell,platelet counts,alpha-fetoprotein and protein induced by vitamin K absence or antagonist II levels were used to develop LR,SVM,RF,and LASSO regression *** RF model exhibited superior discrimination,and the area under curve of the training and validation sets was 0.969 and 0.858,*** values significantly surpassed those of the LR(0.850 and 0.827),SVM(0.860 and 0.803),LASSO regression(0.845 and 0.831),and ASAP(0.866 and 0.813)model

关键词： Hepatocellular carcinoma Cirrhosis Prediction model Machine learning Random forest

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新能源汽车氢气加注过程的模拟

专用汽车 2021年第5期 58-62页

作者：夏婉扬王旭敏王豫毕诚武汉理工大学汽车工程学院湖北武汉430070 中汽研汽车检验中心(武汉)有限公司湖北武汉430056 武汉轻工大学电气与电子工程学院湖北武汉430048

高压储氢罐在新能源汽车上具有广泛的应用,而车用氢气需满足里程及安全性的要求,如何实现安全高效的氢气加注是目前面临的主要问题。根据质量与能量守恒定律、气体状态方程以及传热理论,建立了充气过程的数学模型并求出解析解,并通过Mat... 详细信息

高压储氢罐在新能源汽车上具有广泛的应用,而车用氢气需满足里程及安全性的要求,如何实现安全高效的氢气加注是目前面临的主要问题。根据质量与能量守恒定律、气体状态方程以及传热理论,建立了充气过程的数学模型并求出解析解,并通过Matlab/Simulink仿真平台建立了双区双温集总参数模型。在对模型进行修正与验证后,使用双区双温模型分析环境温度、进气温度、充气速率以及初始压力等参数对充气过程的影响。研究结果表明,这4个参数均会对罐内温度与压力变化造成较大影响,其中充气速率与进气温度为关键影响因素。为此,特选取充气速率与进气温度这2个参数来讨论其参数变化对充气过程的影响。最后基于以上的参数研究,给出合适的充气建议。

关键词：氢气充气过程双区模型解析解

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高校实践课程线上教学的改革模式探讨

教育教学论坛 2021年第10期 61-64页

作者：田哲文夏婉扬魏晓旭武汉理工大学现代汽车零部件技术湖北省重点实验室湖北武汉430070 武汉理工大学汽车零部件技术湖北省协同创新中心湖北武汉430070 武汉理工大学湖北省新能源与智能网联车工程技术研究中心湖北武汉430070

针对疫情下"汽车拆装实习"课程无法进行传统教学模式的问题,结合现有网络教学平台资源建设,提出了"以科学探究为主线、能力素质培养为核心"的线上实践课程教学改革模式探索。采用学生自主预习、教师讲授与学生讨论法相结合的教学方案,... 详细信息

针对疫情下"汽车拆装实习"课程无法进行传统教学模式的问题,结合现有网络教学平台资源建设,提出了"以科学探究为主线、能力素质培养为核心"的线上实践课程教学改革模式探索。采用学生自主预习、教师讲授与学生讨论法相结合的教学方案,通过学生出勤率、上课互动情况以及线上作业提交情况作为课程成绩考核依据。实践表明,线上课程教学能有效地在疫情下完成教学工作,也为传统教学模式的改革探索提供了新的思路。

关键词：线上实践课程汽车拆装教学模式

CDCAT: A Multi-Language Cross-Document Entity and Event Coreference Annotation Tool

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Tsinghua Science and Technology 2022年第3期27卷 589-598页

作者： yang Xu Boming xia Yueliang wan Fan Zhang Jiabo Xu Huansheng Ning School of Computer and Communication Engineering University of Science and Technology BeijingBeijing 100083China Beijing Engineering Research Center for Cyberspace Data Analysis and Applications Beijing 100083China Research Institute with Run Technologies Company Ltd.Beijing 100192China School of Information Engineering Xinjiang Institute of EngineeringUrumqi 830091China

A tool for the manual annotation of cross-document entity and event coreferences that helps annotators to label mention coreference relations in text is essential for the annotation of coreference corpora. To the best of our knowledge, CROss-document Main Events and entities Recognition(CROMER) is the only open-source manual annotation tool available for cross-document entity and event coreferences. However, CROMER lacks multi-language support and extensibility. Moreover, to label cross-document mention coreference relations, CROMER requires the support of another intra-document coreference annotation tool known as Content Annotation Tool, which is now unavailable. To address these problems, we introduce Cross-Document Coreference Annotation Tool(CDCAT), a new multi-language open-source manual annotation tool for cross-document entity and event coreference, which can handle different input/output formats, preprocessing functions, languages, and annotation systems. Using this new tool, annotators can label a reference relation with only two mouse clicks. Best practice analyses reveal that annotators can reach an annotation speed of 0.025 coreference relations per second on a corpus with a coreference density of 0.076 coreference relations per word. As the first multi-language open-source cross-document entity and event coreference annotation tool, CDCAT can theoretically achieve higher annotation efficiency than CROMER.

关键词： event coreference entity coreference manual annotation tool natural language processing

What Security Questions Do Developers Ask？ A Large-Scale Study of Stack Overflow Posts

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Journal of Computer Science & Technology 2016年第5期31卷 910-924页

作者： Xin-Li yang David Lo Xin xia Zhi-Yuan wan Jian-Ling Sun College of Computer Science and Technology Zhejiang University Hangzhou 310027 China School of Information Systems Singapore Management University Singapore Singapore

Security has always been a popular and critical topic. With the rapid development of information technology, it is always attracting people＇s attention. However, since security has a long history, it covers a wide range of topics which change a lot, from classic cryptography to recently popular mobile security. There is a need to investigate security-related topics and trends, which can be a guide for security researchers, security educators and security practitioners. To address the above-mentioned need, in this paper, we conduct a large-scale study on security-related questions on Stack Overflow. Stack Overflow is a popular on-line question and answer site for software developers to communicate, collaborate, and share information with one another. There are many different topics among the numerous questions posted on Stack Overflow and security-related questions occupy a large proportion and have an important and significant position. We first use two heuristics to extract from the dataset the questions that are related to security based on the tags of the posts. And then we use an advanced topic model, Latent Diriehlet Allocation （LDA） tuned using Genetic Algorithm （GA）, to cluster different security-related questions based on their texts. After obtaining the different topics of security-related questions, we use their metadata to make various analyses. We summarize all the topics into five main categories, and investigate the popularity and difficulty of different topics as well. Based on the results of our study, we conclude several implications for researchers, educators and practitioners.

关键词： security Stack Overflow empirical study topic model

Fano-Resonance of a Planar Metamaterial

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Chinese Physics Letters 2013年第7期30卷 202-204页

作者： HUANG wan-xia The College of Physics and Electronic Information Anhui Normal UniversityWuhu 241000

We demonstrate experimentally a intriguing Fano-resonance in a perforated planar metamaterial with hole and slit *** transmission strength of the Fano-resonance is modulated by interference between the composite diffracted evanescent wave and the direct transmission field instead of by the coupling between two plasmonic *** metamaterials might have potential applications in future designs of plasmonic devices.

关键词： composite perforated coupling

Molecularly Imprinted Polymers on Chloromethyl Polystyrene Resin Prepared via RAFT Polymerization

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Chinese Chemical Letters 2006年第4期17卷 549-552页

作者： Zhen xia DU Hong LIU Zhi Feng FU wan Tai yang Key Laboratory for Controlled Chemical Reactions of Education Ministry Beijing University of Chemical Technology Beijing 100029

Surface molecularly imprinted polymers （SMIP） was prepared via the reversible addition-fragmentation chain transfer （RAFT） polymerization on the chloromethyl polystyrene resin （CPR） in the presence of the template D-phenylalanine. The structure of SMIP was characterized by FTIR and SEM. The adsorption behavior of D-phenylalanine of SMIP was preliminarily investigated.

关键词： Surface molecularly imprinted polymers reversible addition-fragmentation chain transfer.

Dehydroxylation action on surface of TiO_2 films restrained by nitrogen carrier gas during atomic layer deposition process

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Rare Metals 2014年第5期33卷 583-586页

作者： Zhi-Peng Rao Bang-Wu Liu Chao-Bo Li yang xia Jun wan Key Laboratory of Microelectronic Devices and Integration Technology Institute of Microelectronics Chinese Academy of Sciences Jiaxing Research and Commercialization Center for Microelectronics Equipment Zhejiang Institute of Advanced Technology Chinese Academy of Sciences Jiaxing Kemin Electronic Equipment & Technologies Co. LtdZhejiang Institute of Advanced Technology Chinese Academy of Sciences

A strong influence of nitrogen gas on the content of surface hydroxyl groups of TiO2 films by atomic layer deposition（ALD） was investigated by X-ray photoelectron spectroscopy（XPS）, contact angle measuring system, and UV–Vis spectrophotometer. XPS spectra of O 1s indicate that the content of surface hydroxyl groups is varied when using N2 as carrier gas. The results of water contact angles and optical reflection spectra show that the content variation of surface hydroxyl groups influences the wetting properties and optical reflectivity of TiO2 films. A surface reaction model is suggested to explain the ALD reaction process using N2 as carrier gas.

关键词： Atomic layer deposition TiO2 N2 Surface hydroxyl groups XPS Reaction model