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Molecular dynamics simulations of helium transport through inorganic mineral nanopores

Science China Earth Sciences 2025年第1期68卷 237-252页

作者： dandan song Ping GUAN Chi ZHANG Jiahao REN School of Earth and Space Sciences Peking UniversityBeijing100871China

Helium transport through nanoscale inorganic mineral pores and pore throats is essential for its overall *** elucidate helium's transport dynamics within nanopores,we employed equilibrium and non-equilibrium molecular dynamics simulations to investigate helium's static self-diffusion and pressure-driven flow in quartz slit-shaped *** also introduced water and various gases,including hydrogen,methane,ethane,nitrogen,and carbon dioxide,into the nanopores to assess their influence on helium *** findings indicate minimal helium adsorption on quartz pore *** conditions where the pore size is less than 5 nm and the pressure under 10 MPa,environmental factors markedly influence helium *** pore sizes,high temperatures,and low gas pressures enhance helium desorption and facilitate faster *** observed a positive correlation between helium flow velocity and factors such as pore size,pressure gradient,and surface smoothness of the ***,the presence of pore water and carrier gases in quartz nanopores,which diffuse more slowly than helium,tends to reduce helium surface adsorption and slow its *** the carrier gases studied,nitrogen showed similar adsorption capacity,diffusivity,and stability to helium,while carbon dioxide displayed the highest adsorption capacity and the slowest diffusion rate,markedly differing from *** on the simulation results,we concluded that water and carrier gases primarily function as transport mediums in helium migration,moving together with ***,which shares similar properties with helium,effectively assists in this co-migration ***,carbon dioxide,due to its high adsorption capacity and slow diffusion,tends to be lost during *** a result,gas reservoirs with high nitrogen levels and low carbon dioxide levels are more likely to have higher helium ***,the smaller pore sizes and higher gas pressures in caproc

关键词： Helium transport Slit nanopores Molecular dynamics simulations Diffusion Flow carriers

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A fuzzy model of predicting RNA secondary structure

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Science in China(Series F) 2007年第6期50卷 846-866页

作者： song dandan DENG ZhiDong Department of Computer Science National Laboratory of Information Science and TechnologyTsinghua University Beijing 100084 China

We propose a novel model to predict RNA secondary structure based on the fuzzy sets theory. Through the fuzzy partition of state spaces and the incorporation of fuzzy goals, we can find the optimal fuzzy policy of the model using fuzzy dynamic programming algorithm effectively, and then determine optimal and suboptimal RNA secondary structures. Compared to the existing sophisticated prediction models, such as Zuker＇s method and the SCFG model, our fuzzy model based approach has many advantages： 1） computational complexity can be reduced by the fuzzy partition; 2） the optimal secondary structure and several suboptimal ones can be generated simultaneously; and 3） subjective prior knowledge can readily be incorporated. This paper presents a complete description of our fuzzy model and gives the implementation of the proposed method. We also apply the BJK fuzzy model structure to secondary structure predictions based on datasets of tRNA and tmRNA sequences. By the comparison of our fuzzy method with both the minimum free energy based mfold tool and the BJK grammar model of SCFG, our experimental results validate the effectiveness of the proposed method and the prediction accuracy is shown to be further improved.

关键词： RNA secondary structure fuzzy model fuzzy dynamic programming

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PSVM: a preference-enhanced SVM model using preference data for classification

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Science China(Information Sciences) 2017年第12期60卷 165-178页

作者： Lerong MA dandan song Lejian LIAO Jingang WANG Engineering Research Center of High Volume Language Information Processing and Cloud Computing Applications School of Computer Science and Technology Beijing Institute of Technology College of Mathematics and Computer Science Yan'an University Search Business Department Alibaba Group

Classification is an essential task in data mining, machine learning and pattern recognition *** classification models focus on distinctive samples from different categories. There are fine-grained differences between data instances within a particular category. These differences form the preference information that is essential for human learning, and, in our view, could also be helpful for classification models. In this paper, we propose a preference-enhanced support vector machine(PSVM), that incorporates preference-pair data as a specific type of supplementary information into SVM. Additionally, we propose a two-layer heuristic sampling method to obtain effective preference-pairs, and an extended sequential minimal optimization(SMO)algorithm to fit PSVM. To evaluate our model, we use the task of knowledge base acceleration-cumulative citation recommendation(KBA-CCR) on the TREC-KBA-2012 dataset and seven other datasets from UCI,Stat Lib and ***. The experimental results show that our proposed PSVM exhibits high performance with official evaluation metrics.

关键词： preference SVM classification sampling sequential minimal optimization(SMO)

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A Bayesian Recommender Model for User Rating and Review Profiling

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Tsinghua Science and Technology 2015年第6期20卷 634-643页

作者： Mingming Jiang dandan song Lejian Liao Feida Zhu School of Computer Science and Technology Beijing Institute of Technology School of Information Systems Singapore Management University

Intuitively, not only do ratings include abundant information for learning user preferences, but also reviews accompanied by ratings. However, most existing recommender systems take rating scores for granted and discard the wealth of information in accompanying reviews. In this paper, in order to exploit user profiles’ information embedded in both ratings and reviews exhaustively, we propose a Bayesian model that links a traditional Collaborative Filtering(CF) technique with a topic model seamlessly. By employing a topic model with the review text and aligning user review topics with 'user attitudes'(i.e., abstract rating patterns) over the same distribution, our method achieves greater accuracy than the traditional approach on the rating prediction task. Moreover, with review text information involved, latent user rating attitudes are interpretable and 'cold-start' problem can be *** property qualifies our method for serving as a 'recommender' task with very sparse datasets. Furthermore,unlike most related works, we treat each review as a document, not all reviews of each user or item together as one document, to fully exploit the reviews’ information. Experimental results on 25 real-world datasets demonstrate the superiority of our model over state-of-the-art methods.

关键词： collaborative filtering topic model recommender sy

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A Latent Entity-Document Class Mixture of Experts Model for Cumulative Citation Recommendation

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Tsinghua Science and Technology 2018年第6期23卷 660-670页

作者： Lerong Ma Lejian Liao dandan song Jingang Wang Engineering Research Center of High Volume Language Information Processing and Cloud Computing Applications Beijing Institute of Technology College of Mathematics and Computer Science Yan'an University

Knowledge Bases （KBs） are valuable resources of human knowledge which contribute to many applications. However, since they are manually maintained, there is a big lag between their contents and the upto-date information of entities. Considering a target entity in KBs, this paper investigates how Cumulative Citation Recommendation （CCR） can be used to effectively detect its worthy-citation documents in large volumes of stream data. Most global relevant models only consider semantic and temporat features of entity-document instances, which does not sufficiently exploit prior knowledge underlying entity-document instances. To tackle this problem, we present a Mixture of Experts （ME） model by introducing a latent layer to capture relationships between the entity-document instances and their latent class information. An extensive set of experiments was conducted on TREC-KBA-2013 dataset. The results show that the model can significantly achieve a better performance gain compared to state-of-the-art models in CCR.

关键词： knowledge base acceleration cumulative citation recommendation Mixture of Experts (ME) LatentEntity-Document Classes (LEDCs)

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痤疮炎症方联合多西环素治疗炎症性痤疮的效果观察

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中国美容医学 2025年第1期34卷 95-99页

作者：宋丹丹钟咪吴茜杰江南大学附属医院皮肤科江苏无锡214062

目的:研究痤疮炎症方联合多西环素治疗炎症性痤疮的效果及对患者情绪状态、面部美观的影响。方法:选取2022年1月-2023年8月江南大学附属医院收治的炎症性痤疮患者82例,随机抽签法分为对照组(41例)和观察组(41例)。对照组采用多西环素,... 详细信息

目的:研究痤疮炎症方联合多西环素治疗炎症性痤疮的效果及对患者情绪状态、面部美观的影响。方法:选取2022年1月-2023年8月江南大学附属医院收治的炎症性痤疮患者82例,随机抽签法分为对照组(41例)和观察组(41例)。对照组采用多西环素,观察组于对照组的基础上予以痤疮炎症方,两组均进行治疗6周。统计两组治疗6周后的临床疗效,治疗前及治疗6周后痤疮特异性生活质量调查问卷、炎性皮损、焦虑、抑郁评分、VISIA评分,研究期间安全性。结果:治疗6周后,观察组临床总有效率97.56%高于对照组的82.93%;较治疗前,治疗6周后两组痤疮特异性生活质量调查问卷各项评分均升高,且观察组高于对照组(P<0.05);炎性皮损、焦虑、抑郁、红色区、紫质各项评分则均降低,且观察组低于对照组(P<0.05)。结论:痤疮炎症方联合多西环素能够有效改善炎症性痤疮患者情绪状态,缓解其炎性皮损情况,提高患者面部美观程度及生活质量,具有较好的治疗效果,同时不会增加不良反应的发生。

关键词：痤疮炎症性多西环素痤疮炎症方面部美观

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基于思维导图构建通气治疗重症肺炎新生儿的协作式“零缺陷”护理模式

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河南医学研究 2025年第3期34卷 563-565页

作者：魏旭霞宋丹丹赵旭平顶山市第一人民医院新生儿重症监护室河南平顶山467000

目的探究基于思维导图构建通气治疗新生儿重症肺炎协作式“零缺陷”护理模式,并观察其临床应用效果。方法本研究为前瞻性随机对照试验,纳入2021年3月至2023年3月平顶山市第一人民医院收治的102例通气治疗新生儿重症肺炎患儿,根据随机... 详细信息

目的探究基于思维导图构建通气治疗新生儿重症肺炎协作式“零缺陷”护理模式,并观察其临床应用效果。方法本研究为前瞻性随机对照试验,纳入2021年3月至2023年3月平顶山市第一人民医院收治的102例通气治疗新生儿重症肺炎患儿,根据随机数表法分为对照组(51例)和研究组(51例)。对照组接受协作式“零缺陷”护理,研究组接受基于思维导图构建的协作式“零缺陷”护理模式。统计患儿(咳嗽、发热、肺啰音)消退时间,采用小儿危重病例评分(PCIS)评估患儿康复进程,统计患儿住院期间误吸、漏气、喉梗阻、皮肤损伤等风险事件发生情况。结果研究组患儿咳嗽、发热、肺啰音消退时间均短于对照组(P0.05)。结论基于思维导图构建的协作式“零缺陷”护理模式可缩短通气治疗新生儿重症肺炎患儿症状消退时间,加快患儿康复进程,减少风险事件发生。

关键词：重症肺炎新生儿思维导图协作式“零缺陷”护理风险事件

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老年慢性心力衰竭患者血清SCD-1和sVEGFR-2表达水平及其与预后的评估价值研究

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广州医药 2025年第2期56卷 241-246页

作者：黎霏霏宋丹丹潘春荣珠海市第五人民医院检验科广东珠海519055

目的探究血清多配体蛋白聚糖-1(SCD-1)与可溶性血管内皮生长因子受体-2(sVEGFR-2)表达水平在老年慢性心力衰竭患者预后评估的判定价值。方法选取2023年1月—2024年3月珠海市第五人民医院检验科收治的110例老年慢性心力衰竭患者,检测其血... 详细信息

目的探究血清多配体蛋白聚糖-1(SCD-1)与可溶性血管内皮生长因子受体-2(sVEGFR-2)表达水平在老年慢性心力衰竭患者预后评估的判定价值。方法选取2023年1月—2024年3月珠海市第五人民医院检验科收治的110例老年慢性心力衰竭患者,检测其血清SCD-1和sVEGFR-2水平,对患者进行随访调查,了解其再次由于心力衰竭住院、心源性死亡的情况。运用多因素Logistic回归分析,探究老年慢性心力衰竭患者预后影响因素。结果Logistic回归分析显示,心功能分级(OR=3.433,95%CI:0.934~6.431)、B型脑钠肽升高(OR=2.462,95%CI:0.861~4.765)、血清SCD-1升高(OR=3.795,95%CI:0.972~6.894)、血清sVEGFR-2升高(OR=3.842,95%CI:0.942~6.912)为影响老年慢性心力衰竭患者预后不良的重要因素(P<0.05);联合血清SCD-1和sVEGFR-2曲线下面积0.962与B型脑肽钠曲线下面积0.844,相较于单一SCD-1曲线下面积0.658、sVEGFR-2曲线下面积0.712明显偏高(P<0.05)。结论经研究证实,老年慢性心力衰竭患者预后效果不理想,其血清SCD-1和sVEGFR-2监测水平异常升高,和老年慢性心力衰竭预后不佳存在关联性,可视为老年慢性心力衰竭患者判定预后效果的主要标志物。

关键词：多配体蛋白聚糖-1 可溶性血管内皮生长因子受体-2 慢性心力衰竭预后评估价值

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The Multi-Objective Optimization of AFPM Generators with Double-Sided Internal Stator Structures for Vertical Axis Wind Turbines

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Energy Engineering 2021年第5期118卷 1439-1452页

作者： dandan song Lianjun Zhou Ziqi Peng Senhua Luo Jun Zhu Jiangsu Jinfeng Technology Co. Ltd.Yancheng224100China School of Automation Nanjing University of Science and TechnologyNanjing210094China School of Electrical Engineering and Automation Henan Polytechnic UniversityJiaozuo454000China

The axial flux permanent magnet(AFPM)generator with double-sided internal stator structure is highly suitable for vertical axis wind turbines due to its high power *** performance of the AFPM generator with double-sided internal stator structure can be improved by the reasonable design of electromagnetic *** further improve the overall performance of the AFPM generator with double-sided internal stator structure,multivariable(coil widthω_(c),permanent magnet thickness h,pole arc coefficient α_(p) and working air gap l_(g))and multi-objective(generator efficiencyη,total harmonic distortion of the voltage THD and induced electromotive force amplitude EMF)functional relationships are innovatively *** analysis,mean analysis and variance analysis are performed on the influence parameters by combining the Taguchi method and response surface methodology to study the influence degrees of each influence parameter on the optimization objectives to determine the most appropriate electromagnetic *** optimization results are verified by 3D finite element *** optimized APFM generator with double-sided internal stator structure exhibits superior economy,stronger magnetic density,higher efficiency and improved power quality.

关键词： Wind turbine double-sided internal stator structure multi-objective optimization axial flux permanent magnet generator

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数字贸易壁垒对全球价值链的影响

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科技和产业 2025年第1期25卷 356-361页

作者：林硕延李佳展林乐烨宋丹丹广州商学院经济学院广州511363 华南师范大学经济与管理学院广州510006 广西大学农学院南宁530004 广州南方学院商学院广州510970

在数字化背景下诞生的数字贸易是一种新兴的贸易模式,其以数字技术为基础,通过贸易方式的数字化或是贸易对象数字化得以转型。数字贸易在解决时空局限的同时也引现了数字贸易壁垒,成为经济全球化进程中的一大障碍。破除数字贸易壁垒,推... 详细信息

在数字化背景下诞生的数字贸易是一种新兴的贸易模式,其以数字技术为基础,通过贸易方式的数字化或是贸易对象数字化得以转型。数字贸易在解决时空局限的同时也引现了数字贸易壁垒,成为经济全球化进程中的一大障碍。破除数字贸易壁垒,推动全球数字经济协同发展,对优化全球价值链、提升国际贸易效率具有重要意义。为此,着重从数字贸易壁垒与全球价值链之间的关系入手,构建相关理论模型,探讨在“逆全球化”背景下的中国数字贸易发展趋势,并针对这些问题,提出相应对策。

关键词：数字贸易壁垒数字技术全球价值链经济全球化

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