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Friction 2021年第6期9卷 1420-1435页

作者： Yangzhi CHEN yifan lin School of Mechanical and Automotive Engineering South China University of TechnologyGuangzhou 510640China

A calculation method for the friction coefficient and meshing efficiency of plastic line gear(LG)pair under dry friction conditions was studied theoretically and experimentally,taking a polyoxymethylene parallel line gear pair(POM PLGP)as an ***,the geometric and mechanical models of PLGP were built by considering the effects of misalignment and loaded deformation under the actual operating ***,the friction coefficient of POM specimens was obtained via the ball-on-disk experiment,of which the value varies between 0.35 and 0.45 under the experimental *** calculation formula for the friction coefficient of POM LG pair was obtained by fitting the friction coefficient of the POM specimens,and the meshing efficiency of POM LG pair was calculated based on the calculation formula for friction coefficient and the meshing efficiency calculation ***,the meshing efficiency of POM PLGP specimens was measured using a homemade gear meshing efficiency test *** experimental results validated the feasibility of the proposed calculation method for the friction coefficient and meshing efficiency of the plastic LG *** study provides a method for the calculation of the friction coefficient and meshing efficiency of plastic gear pairs under dry friction *** also provides the basis for the wear calculation of plastic LG pair under dry friction conditions.

关键词： line gear(LG)pair friction coefficient meshing efficiency dry friction polyoxymethylene(POM)

内孤立波对同反向传播的表面波的调制特征研究

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中国海洋大学学报（自然科学版） 2025年第1期55卷 1-12页

作者：林一帆徐滔贾村陈旭中国海洋大学海洋与大气学院山东青岛266100 自然资源部第三海洋研究所海洋动力研究室福建厦门361005

当内孤立波在海洋内部传播时,会引起表层水体的辐聚辐散,从而对海表波浪进行调制作用。本文使用计算流体力学(Computational fluid dynamics,CFD)技术,针对内孤立波对表面波的调制问题进行数值模拟研究。建立两层模型,模拟了表面波在同... 详细信息

当内孤立波在海洋内部传播时,会引起表层水体的辐聚辐散,从而对海表波浪进行调制作用。本文使用计算流体力学(Computational fluid dynamics,CFD)技术,针对内孤立波对表面波的调制问题进行数值模拟研究。建立两层模型,模拟了表面波在同反向传播的情况下,不同振幅内孤立波对不同波长表面波的调制过程。基于表面波的波长和波高这两个基本特征,发现内孤立波引起的表层水平流速变化会调制表面波的波高,相同方向传播时,表面波波高会在最大水平流速附近处减小,而相反传播时会增大。同时内孤立波引起的水体辐聚辐散(水平流速梯度)的分布会调制表面波的波长特征,表面波波长会在流场辐散的区域变长,在流场辐聚的区域变短。表面波受调制作用变化的强弱与内孤立波振幅、表面波初始波长相关。内孤立波振幅的增加会加强调制作用,使得表面波波高与波长的变化程度更显著。表面波初始波长增加会减弱调制作用。本研究着重分析了内孤立波对表面波的调制作用,得到了内孤立波引起的上层水体流动和受调制的表面波具体的对应关系与变化规律,有助于更好地理解内孤立波对表面波调制的水动力过程,对于解读内波成像的过程有重要意义。

关键词：内孤立波表面波数值模拟计算流体力学小波分析

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Risk-averse Contextual Multi-armed Bandit Problem with linear Payoffs

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Journal of Systems Science and Systems Engineering 2023年第3期32卷 267-288页

作者： yifan lin Yuhao Wang Enlu Zhou School of Industrial and Systems Engineering Georgia Institute of TechnologyAtlantaGAUSA

In this paper we consider the contextual multi-armed bandit problem for linear payoffs under a risk-averse *** each round,contexts are revealed for each arm,and the decision maker chooses one arm to pull and receives the corresponding *** particular,we consider mean-variance as the risk criterion,and the best arm is the one with the largest mean-variance *** apply the Thompson sampling algorithm for the disjoint model,and provide a comprehensive regret analysis for a variant of the proposed *** T rounds,K actions,and d-dimensional feature vectors,we prove a regret bound of O((1+ρ+1/ρ)d In T ln K/δ√dKT^(1+2∈)ln K/δ1/e)that holds with probability 1-δunder the mean-variance criterion with risk tolerance p,for any 0<ε<1/2,0<δ<*** empirical performance of our proposed algorithms is demonstrated via a portfolio selection problem.

关键词： Multi-armed bandit context risk-averse Thompson sampling

Joint Model of Wind Speed and Corresponding Direction Based on Wind Rose for Wind Energy Exploitation

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Journal of Ocean University of China 2022年第4期21卷 876-892页

作者： YANG Zihao lin yifan DONG Sheng College of Engineering Ocean University of ChinaQingdao 266100China Huadian Heavy Industries Co. Ltd.Beijing 100070China

As a common and extensive datum to analyze wind,wind rose is one of the most important components of the meteorological *** this study,a model is proposed to establish the joint probability distribution of wind speed and direction using grouped data of wind *** the basis of the model,an algorithm is presented to generate pseudorandom numbers of wind speed and paired direction ***,the proposed model and algorithm are applied to two weather stations located in the Liaodong *** the models built for the two cases,a novel graph representing the continuous joint probability distribution of wind speed and direction is plotted,showing a strong correlation to the corresponding wind ***,the joint probability distributions are utilized to evaluate wind energy potential *** cooperation with Monte Carlo simulation,the model can approximately predict annual directional extreme wind speed under different return periods under the condition that the wind rose can represent the meteorological characters of the wind field *** model is beneficial to design and install wind turbines.

关键词： angular-linear distribution wind speed wind direction wind rose wind energy Monte Carlo simulation

Joint Return Value Estimation of Significant Wave Heights and Wind Speeds with Bivariate Copulas

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Journal of Ocean University of China 2023年第5期22卷 1181-1192页

作者： TAO Shanshan DONG Sheng lin yifan GUEDES SOARES Carlos College of Engineering Ocean University of ChinaQingdao 266100China Huadian Heavy Industries Co. Ltd.Beijing 100070China Instituto Superior Técnico Universidade de LisboaLisboa 1049-001Portugal

The joint design criteria of significant wave heights and wind speeds are quite important for the structural reliability of fixed offshore ***,the design method that regards different ocean environmental variables as independent is *** the present study,we introduce a bivariate sample consisting of the maximum wave heights and concomitant wind speeds of the threshold by using the peak-over-threshold and declustering *** selecting the appropriate bivariate copulas and univariate distributions and blocking the sample into years,the bivariate compound distribution of annual extreme wave heights and concomitant wind speeds is *** joint design criteria,namely,the joint probability density method and the conditional probability method,are applied to obtain the joint return values of significant wave heights and wind *** show that(28.5±0.5)m s^(-1)is the frequently obtained wind speed based on the Atlantic dataset,and these joint design values are more appropriate than those calculated by univariate analysis in the fatigue design.

关键词： joint design wave height wind speed compound distribution copula

黄体生成素/促卵泡生成素比值对快进展型中枢性性早熟的预测价值研究

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中国全科医学 2025年第3期28卷 352-357页

作者：袁淑娴林一凡赵艺璇魏怡鲁帅卫海燕郑州大学附属儿童医院内分泌遗传代谢科河南省郑州市450018

背景中枢性性早熟(CPP)是儿童内分泌常见疾病,近年来呈逐年增加趋势,依据青春期发育进程可分为快进展型中枢性性早熟(RP-CPP)和缓慢进展型中枢性性早熟(SP-CPP)。RP-CPP具有极大危害,其与SPCPP在早期临床鉴别中存在困难,主要依靠随访... 详细信息

背景中枢性性早熟(CPP)是儿童内分泌常见疾病,近年来呈逐年增加趋势,依据青春期发育进程可分为快进展型中枢性性早熟(RP-CPP)和缓慢进展型中枢性性早熟(SP-CPP)。RP-CPP具有极大危害,其与SPCPP在早期临床鉴别中存在困难,主要依靠随访中青春期发育进程及骨龄进展情况进行判断,目前缺乏有效的实验室检查指标来预测RP-CPP。目的探讨促黄体生成素(LH)/促卵泡生成素(FSH)比值对RP-CPP的预测价值。方法回顾性选取2020年1月—2022年5月郑州大学附属儿童医院收治的4~10岁CPP女童(n=380),依据青春期发育进程等指标分为RP-CPP组(n=130)及SP-CPP组(n=250),对两组间的临床特征进行对比分析,进行RP-CPP影响因素的单因素和多因素Logistic回归分析,并绘制LH/FSH比值对RP-CPP预测价值的受试者工作特征(ROC)曲线。结果 RP-CPP组女童的身高、体质量、BMI、胰岛素样生长因子1(IGF-1)、骨龄与实际年龄差值、双侧卵巢体积、LH基础值、雌二醇水平、LH基础值/FSH基础值、LH峰值/FSH峰值均高于SP-CPP组(P<0.05)。多因素Logistic回归分析,结果显示,LH基础值(OR=0.882,95%CI=0.686~0.986,P=0.035)及LH峰值/FSH峰值(OR=0.492,95%CI=0.336~0.723,P<0.001)是CPP患者进展为RP-CPP的影响因素。LH基础值/FSH基础值、LH峰值/FSH峰值均与身高、IGF-1、LH基础值、雌二醇水平、LH峰值、卵巢容积及骨龄呈正相关(P<0.05)。ROC曲线显示LH基础值/FSH基础值、LH峰值/FSH峰值较其他指标对RP-CPP的预测价值更高,LH基础值/FSH基础值为0.63时,约登指数最大为0.258[灵敏度为43.1%,特异度为82.7%,ROC曲线下面积(AUC)=0.644],LH峰值/FSH峰值为1.39时,约登指数最大为0.276(灵敏度为74.6%,特异度53.0%,AUC=0.655),二者联合的预测模型优于单一指标预测模型(AUC=0.668)。对未进行临床干预患儿随访6个月后的基础促性腺激素水平进行分析,随访6个月后RP-CPP组的身高增长、ΔLH、ΔFSH、骨龄增长及卵巢容积增长均多于SP-CPP组(P<0.05)。结论 LH基础值/FSH基础值及LH峰值/FSH峰值是RP-CPP的早期预测指标,当LH/FSH基础值≥0.63或LH峰值/FSH峰值≥1.39时,需考虑RP-CPP的可能性,并且二者联合的预测价值优于单一指标,可作为临床应用促性腺激素释放激素类似物治疗的辅助参考指标。

关键词：中枢性性早熟促卵泡激素黄体生成素青春期发育女童病例对照研究

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Recent progress in functionalized layered double hydroxides and their application in efficient electrocatalytic water oxidation

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Journal of Energy Chemistry 2019年第5期28卷 93-104页

作者： Xiaolong Deng Jinzhao Huang Hao Wan Fashen Chen yifan lin Xijin Xu Renzhi Ma Takayoshi Sasaki School of Physics and Technology University of JinanJinan 250022ShandongChina National Institute for Materials Science (NIMS) Beijing Tsinghua University University of Tokyoin the National Institutefor Research in Inorganic Materials International Center for Materials Nanoarchitectonics (WPI-MANA) National Institute for Materials Science (NIMS)Namiki 1-1Tsukubalbaraki 305-0044Japan Northwestern Polytechnical University Shanghai University Konkuk University linyi University Beijing Jiaotong University Instituteof Solid State Physics Chinese Academy of Sciences Nanyang TechnologicalUniversity in Singapore

Layered double hydroxides (LDHs), a class of anionic clays consisting of brucite-like host layers and interlayer anions, have been widely investigated in the last decade due to their promising applications in many areas such as catalysis, ion separation and adsorption. Owing to the highly tunable compositi on and uniform distribution of metal cations in the brucite-like layers, as well as the facile exchangeability of intercalated anions, LDHs can be modified and functionalized to form various nanostructures/composites through versatile processes such as anion intercalation and exfoliation, decoration of nanoparticles, selfassembly with other two-dimensional (2D) materials, and controlled growth on conductive supports (e.g., nanowire arrays, nano tubes, 3D foams). In this article, we briefly review the recent advances on both the LDH nano structures and functionalized composites toward the applications in energy conversion, especially for water oxidation.

关键词： Layered double hydroxide Energy conversion Water splitting Functionalization

Mucosal vaccine development for respiratory viral infections

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hLife 2024年第2期2卷 50-63页

作者： yifan lin Zhenxiang Hu Yang-Xin Fu Hua Peng Department of Basic Medical Sciences School of MedicineTsinghua UniversityBeijingChina LivzonBio Inc. GuangdongChina Guangzhou Laboratory Guangzhou International Bio IslandGuangdongChina

Mucosal vaccines have risen to prominence in the corona virus disease 2019(COVID-19)pandemic due to their ability to elicit both local antibody and tissue-resident T cell responses,affording a dual-layered defense against infection and transmission at respiratory entry *** intramuscular vaccines predominantly focus on systemic immunity,mucosal vaccines offer a more nuanced,site-specific ***,the field faces a dearth of mucosal vaccine options for respiratory diseases,starkly contrasting to the extensive array of well-characterized injectable *** unique features of mucosal surfaces necessitate specialized adjuvants and delivery systems,adding complexity to adapting injectable vaccine technologies for mucosal ***,we review the recent insights into the specificities of respiratory mucosal immunology that provide a foundation for future innovations besides the emerging vaccine platforms,newly discovered adjuvants,and vaccine delivery systems,which may open promising avenues for developing mucosal vaccines targeting respiratory pathogens.

关键词： mucosal immunology respiratory viruses vaccine adjuvants

Channel pruning on frequency response

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Science China(Information Sciences) 2025年第1期68卷 159-170页

作者： Hang lin yifan PENG lin BIE Chenggang YAN Xibin ZHAO Yue GAO School of Software Tsinghua University School of Automation Hangzhou Dianzi University

Network pruning has a significant role in reducing network parameters and accelerating the inference time of the network. Some existing methods prune the network based on the frequency of the data, and finally obtain a sub-network with high accuracy. However, according to our experimental analysis, different frequencies of information in the data contribute differently to the accuracy of the model, and using this information directly for pruning without making a selection will lead to incorrect results. We believe that pruning should retain the convolutional kernels in the network that process important information, while those kernels that process unimportant information should be removed. In this paper, we first investigate the meaning of each frequency band information in the spectrum and their contribution to the prediction accuracy of the network,and according to these results, we propose a new pruning method based on frequency response(PFR). Our PFR finds and removes the convolutional kernels in the network that specialize in processing unimportant information, resulting in a compact neural network model. PFR obtains significant experimental results on different datasets, for example, a 56.0% raduction of float points operations(FLOPs) on Res Net-50 and only 0.37% of Top-1 accuracy degradation on the Image Net dataset.

关键词： deep learning model compression filter pruning channel pruning frequency response

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Anti-oxidative effect of zinc in human umbilical cord mesenchymal stem cells

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Biophysics Reports 2021年第2期7卷 142-151页

作者： Xiaodan Lu yifan lin Xiuying lin Qiang Zhang Zihang Wang Xuguang Mi Ruobing Wang Xiaofang Zhang Xu Luan Yan Liu Bing Li Yan Tan Yanqiu Fang Diagnostic Medical Center Jilin Province People's Hospital School of Medicine Changchun University of Chinese Medicine Department of Clinical Laboratory the Second Hospital of Jilin University General Surgery the First Hospital of Jilin University

Human umbilical cord mesenchymal stem cells(HUC-MSCs) are pluripotent and functional in many biological processes, by which releasing secretary factors to promote the self-repairing of damaged tissue or developing into functional cell at local organ. However, there is a high risk that oxidative stress would reduce the pluripotency and factor-secretion during the preparation and transplantation. Therefore, reducing oxidative stress is expected to improve the efficacy of HUC-MSCs therapy. Zinc(Zn) is an essential trace element which involves in the resistance of oxidative stress. To investigate Zn-regulated signaling pathways, we have profiled the gene expression at transcriptome level in primary HUC-MSCs treated with zinc sulfate, followed with GO and KEGG gene enrichment analysis. Zn treatment improved signal pathways for mineral absorption, cell growth, and cell death. Zn deficiency was mimicked by TPEN administration, which suppressed cell proliferation and reduced the expression of HUCMSCs surface stem cell markers CD73, CD90 and CD105 by flow cytometry. Nuclear factor erythrocyte2 related factor 2(Nrf2) plays an important role in antioxidant biological processes. In vitro treatment of Zn significantly increased Nrf2 and Sirt3 expression at gene level and protein level respectively. Zn supplementation inhibited TPEN-induced failure of cell survival and reversed the reduction of Nrf2 and Sirt3 expression, which further reduced the production of ROS. Zn successfully presented its antioxidation effect by activating Nrf2/Sirt3 signaling pathway in HUC-MSCs. Zn supplementation may improve the efficacy of HUC-MSCs therapy with reduced oxidative stress.

关键词： Zinc Oxidative stress Nuclear factor erythroid-2-related factor 2 Sirtuin 3 Human umbilical cord mesenchymal stem cells