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Preparation and characteristics of TEMPO-oxidized cellulose nanofibrils from bamboo pulp and their oxygen-barrier application in PLA films

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Frontiers of Chemical Science and Engineering 2017年第4期11卷 554-563页

作者： Wu, Bozhen Geng, Biyao chen, yufei Liu, Hongzhi Wu, Qiang Li, Guangyao Zhejiang Univ Technol Coll Mat Sci & Engn Hangzhou 310014 Zhejiang Peoples R China Zhejiang Prov Collaborat Innovat Ctr Bamboo Resou Hangzhou 311300 Zhejiang Peoples R China Zhejiang Agr & Forestry Univ Sch Engn Hangzhou 311300 Zhejiang Peoples R China

Bleached bamboo kraft pulp was pretreated by 2,2,6,6-tetramethylpiperidine-l-oxy radical （TEMPO）- mediated oxidation using a TEMPO/NaBr/NaC10 system at pH = 10 in water to facilitate mechanical disintegration into TEMPO-oxidized cellulose nanofibrils （TO-CNs）. A series of TO-CNs with different carboxylate contents were obtained by varying amounts of added NaC10. An increase in carboxylate contents results in aqueous TO-CN dispersions with higher yield, zeta potential values, and optical transparency. When carboxylate groups are introduced, the DPv value of the TO-CNs remarkably decreases and then levels off. And the presence of hemicellulose in the pulp is favorable to TEMPO oxidization. After the oxidization, the native cellulose I crystalline structure and crystal size of bamboo pulp are almost maintained. TEM micrographs revealed that the degree of nanofibrillation is directly proportional to the carboxylate contents. With increasing carboxylate con- tents, the free-standing TO-CN films becomes more transparent and mechanically stronger. The oxygen permeability of PLA films drastically decreases from 355 for neat PLA to 8.4 mL-1 m a. d-1 after coating a thin layer of TO-CN with a carboxylate content of 1.8 mmol.g1. Therefore, inexpensive and abundant bamboo pulp would be a promising starting material to isolate cellulose nanfibrils for oxygen-barrier applications.

关键词： bamboo TEMPO cellulose nanofibrils oxy-gen barrier

Passive Localization of Signal Source Based on UAVs in Complex Environment

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China Communications 2020年第2期17卷 107-116页

作者： Pengwu Wan Qiongdan Huang Guangyue Lu Jin Wang Qianli Yan yufei chen XI’AN University of Posts and Telecommunications

For the influence caused by multipath fading and non-line-of-sight(NLOS)transmission,it is challenging to accurately localize a moving signal source in complex environment by using the wireless sensor network(WSN)on the *** this paper,we establish a special WSN in the sky to address this challenge,where each sensor is loaded on an unmanned aerial vehicle(UAV)and the operation center of all the UAVs is fixed on the *** on the analyzing of the optimal distribution and the position error calibration of all the sensors,we formulate the localization scheme to estimate the position of the target source,which combines the time difference of arrival(TDOA)method and the frequency difference of arrival(FDOA)*** by employing the semidefinite programming approach,we accurately obtain the position and velocity of the signal *** the simulation,the validity of the proposed method is verified through the performance comparison.

关键词： passive localization time difference of arrival wireless sensor network unmanned aerial vehicle semidefinite programming

Evaluation of fog warning system on driving under heavy fog condition based on driving simulator

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Journal of Intelligent and Connected Vehicles 2021年第2期4卷 41-51页

作者： Xiaohua Zhao Xuewei Li yufei chen Haijian Li Yang Ding Beijing University of Technology BeijingChina and Tsinghua University State Key Laboratory of Automotive Safety and EnergyBeijingChina China Automotive Engineering Research Institute BeijingChina Beijing University of Technology BeijingChina

Purpose–Heavy fog results in low visibility,which increases the probability and severity of trafﬁc crashes,and fog warning system is conducive to the reduction of crashes by conveying warning messages to *** paper aims at exploring the effects of dynamic message sign(DMS)of fog warning system on driver ***/methodology/approach–First,a testing platform was established based on driving simulator and driver performance data under DMS were *** experiment route was consisted of three different zones(*** zone,transition zone and heavy fog zone),and mean speed,mean acceleration,mean jerk in the whole zone,ending speed in the warning zone and transition zone,maximum deceleration rate and mean speed reduction proportion in the transition zone and heavy fog zone were ***,the one-way analysis of variance was applied to test the signiﬁcant difference between the ***,drivers’subjective perception was also ***–The results indicated that DMS is beneﬁcial to reduce speed before drivers enter the heavy fog ***,when drivers enter a heavy fog zone,DMS can reduce the tension of drivers and make drivers operate more ***/value–This paper provides a comprehensive approach for evaluating the effectiveness of the warning system in adverse conditions based on the driving simulation test *** method can be extended to the evaluation of vehicle-to-infrastructure technology in other special scenarios.

关键词： Heavy fog conditions Fog warning system Dynamic message sign Driver performance Driving simulator

Preparation and Thermal Stability of AlMoON Based Solar Selective Absorption Coating

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Journal of Wuhan University of Technology(Materials Science) 2024年第4期39卷 854-862页

作者：闵捷 YUAN Wenxu chen yufei LAN Yapeng YAN Mengdi LIU Hanze chenG Xudong 代路 Hubei Provincial Key Laboratory of Green Materials for Light Industry Hubei University of TechnologyWuhan 430068China Col-laborative Innovation Center of Green Light-weight Materials and Processing Hubei University of TechnologyWuhan 430068China School of Materials and Chemical Engineering Hubei University of TechnologyWuhan 430068China School of Industrial Design Hu-bei University of TechnologyWuhan 430068China State Key Laboratory of Advanced Technology for Materials Synthesis and Process-ing Wuhan University of TechnologyWuhan 430070China Science and Technology on Thermal Energy and Power Laboratory Wuhan Second Ship Design&Research InstituteWuhan 430205China

AlMoON based solar selective absorption coatings were deposited on stainless steel substrate by magnetron *** coatings included infrared reflection layer Mo,absorption layer AlMoN,absorption layer AlMoON and antireflection layer AlMoO from bottom to *** surface of the deposited coatings is flat without obvious *** absorptivity and emissivity are 0.896 and 0.09,respectively,and the quality factor is *** heat treatment at 500℃-36 h,the surface roughness of the coating increases,a small number of cracks and other defects appear,and the broken part is still attached to the coating surface.A certain degree of element diffusion occurs in the coatings,resulting in the decline of the optical properties of the *** absorptivity and emissivity are 0.883 and 0.131,respectively,the quality factor is 7.06,and the PC value is *** coatings do not fail under this condition and have certain thermal stability.

关键词： AlMoON coating preparation thermal stability

Integration of interlayer surface enhancement technologies into metal additive manufacturing:A review

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Journal of Materials Science & Technology 2023年第34期165卷 94-122页

作者： yufei chen Xiancheng Zhang Donghong Ding Xiaowei Wang Kaiming Zhang Yixin Liu Tiwen Lu Shantung Tu Key Laboratory of Pressure Systems and Safety Ministry of EducationEast China University of Science and TechnologyShanghai 200237China School of Mechanical and Power Engineering Nanjing Tech UniversityNanjing 211816China Institute of Reliability Centered Manufacturing Nanjing Tech UniversityNanjing 211816China Jiangsu Key Lab of Design and Manufacture of Extreme Pressure Equipment Nanjing 211816China College of Materials Shanghai Dianji UniversityShanghai 201306China

Additive manufacturing(AM)has the advantages of rapid prototyping,high design freedom,and flexible manufacturing,while the mechanical properties of additively manufactured products are not uniform due to inherent defects and residual *** of interlayer surface enhancement(SE)technologies into AM is a potential solution to improve the microstructure,close defects,residual stress state,mechanical properties,and chemical properties of formed *** paper reviews the current literature on hybrid AM process through the combination of SE and AM,and proves the possibility of integrating SE technologies into AM from the technical *** the improvement effects of SE processes on AM parts are introduced in terms of microstructure,defects,residual stress,mechanical properties,and chemical ***,considering the commonly used directed energy deposition(DED)process and ultrasonic impact treatment(UIT),a closed-loop quality control framework for integration of interlayer UIT into the DED process is *** research directions to the hybrid AM and interlayer SE are pointed out.

关键词： Surface enhancement Additive manufacturing Residual stress Multi-sensor monitoring

Branched tetraether lipids in Chinese soils:Evaluating the fidelity of MBT/CBT proxies as paleoenvironmental proxies

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Science China Earth Sciences 2016年第7期59卷 1353-1367页

作者： ZHENG FengFeng ZHANG ChuanLun chen yufei LI FuYan MA CenLing PU Yang ZHU YuanQing WANG YongLi LIU WeiGuo State Key Laboratory of Marine Geology Tongji UniversityShanghai 200092China School of Geography and Remote Sensing Nanjing University of lnformation Science&TechnologyNanjing 210044China Earthquake Administration of Shanghai Municipality Shanghai 200062China Key Laboratory of Gas Geochemistry Institute of Geology and GeophysicsChinese Academy of SciencesLanzhou 730000China State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi'an 710075China

The ubiquitous occurrence of branched glycerol dialkyl glycerol tetraethers(br GDGTs) in soils has allowed development of new proxies for reconstruction of past climate and environment. The methylation and cyclization degrees of br GDGTs, expressed as MBT and CBT, respectively, are reported to be mainly controlled by mean annual air temperature(MAAT) and soil p H. However, the br GDGT-derived temperatures and soil p H scatter widely when data from different environmental conditions are considered. In this study, we collected over 300 soil samples from China, which are representative of humid(Xishuangbanna, Guangzhou, and Shanghai), semi-arid(Dongying) and semi-arid/arid(Lanzhou, Tibetan Plateau) regions. Collectively we have the most extensive dataset that broadly characterizes the distribution of br GDGTs according to climate zones in China. The overall data demonstrate that the MBT/CBT derived temperatures better match the measured MAATs in humid and non-alkaline regions than those from regions of low MAP(7.0–7.5). Similarly, CBT describes soil p H much better in humid and non-alkaline soils than in semi-arid/arid and alkaline soils; the semi-arid/arid and alkaline soils tend to show a positive correlation between soil p H and CBT, which contradicts that in the humid and non-alkaline soils. While soil p H, MAAT and mean annual precipitation(MAP) are dominating factors controlling the br GDGT distribution across all climate zones, conductivity, total organic carbon and total nitrogen, as well as soil water content can also play an important role locally. Removing br GDGT-II resulted in a revised CBT index that provides more accurate estimation of p H, especially in semi-arid/arid and alkaline soils. The overall Chinese dataset demonstrates that continental air temperature derived from br GDGT-proxies can vastly deviate from real measurements and should be used with extreme caution in paleo-climate or-environment studies.

关键词： brGDGTs MAAT Soil pH MAP Chinese soils Tibetan Plateau Chinese Loess Plateau

A failure criterion for shale considering the anisotropy and hydration based on the shear slide failure model

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International Journal of Mining Science and Technology 2023年第4期33卷 447-462页

作者： Qiangui Zhang Bowei Yao Xiangyu Fan Yong Li Nicholas Fantuzzi Tianshou Ma yufei chen Feitao Zeng Xing Li Lizhi Wang Petroleum Engineering School Southwest Petroleum UniversityChengdu 610500China Department of Civil Geological and Mining EngineeringÉcole Polytechnique de MontréalMontreal H3T 1J4Canada State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu 610500China School of Geoscience and Technology Southwest Petroleum UniversityChengdu 610500China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400030China Department of Civil ChemicalEnvironmental and Materials EngineeringUniversity of BolognaBologna 40136Italy Department of Civil and Mineral Engineering University of TorontoToronto M5S 1A4Canada

A failure criterion fully considering the anisotropy and hydration of shale is essential for shale formation stability ***,a novel failure criterion for hydration shale is developed by using Jaeger’s shear failure criterion to describe the anisotropy and using the shear strength reduction caused by clay minerals hydration to evaluate the *** failure criterion is defined with four parameters in Jaeger’s shear failure criterion(S_(1),S_(2),a andφ),three hydration parameters(k,ω_(sh)andσ_(s))and two material size parameters(d and l0).The physical meanings and determining procedures of these parameters are *** accuracy and applicability of this failure criterion are examined using the published experimental data,showing a cohesive agreement between the predicted values and the testing results,R^(2)=0.916 and AAREP(average absolute relative error percentage)of 9.260%.The error(|D_(p)|)is then discussed considering the effects ofβ(angle between bedding plane versus axial loading),moisture content and confining pressure,presenting that|Dp|increases whenβis closer to 30°,and|D_(p)|decreases with decreasing moisture content and with increasing confining ***,|D_(p)|is demonstrated as being sensitive to S1and being steady with decrease in the data set whenβis 0°,30°,45°and 90°.

关键词： Shale Failure criterion Mechanical strength Shear slide failure Anisotropy Hydration

ATP6V0d2 mediates leucine-induced mTORCI activation and polarization of macrophages

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Protein & Cell 2019年第8期10卷 615-619页

作者： Pingfei Li Xiaofei Deng Jing Luo yufei chen Guoyu Bi Feili Gong Zhengping Wei Na Liu Huabin Li Arian Laurence Xiang-Ping Yang Department of Immunology School of Basic Medicine Tongji Medical College Huazhong University of Science and Technology Wuhan 430030 China Department of Immuno logy School of Basic Medicine Hubei University of Medicine Shiyan 442000 China The First Affiliated Hospital Biomedical Translational Research Institute and Guangdong Province Key Laboratory of Molecular Immunology and Antibody Engineering Jinan University Guangzhou 510632 China Department of Otolaryngology-Head and Neck Surgery Center for Allergic and Inflammatory Diseases Affiliated Eye and ENT Hospital Fudan University Shanghai 200031 China Department of Haematology University College London Hospitals NHS trust London UK

Dear Editor, mTORCI, as a center regulatory hub of metabolism, senses the cellular energy status, nutrition and extracellular stimuli and regulates cell growth, differentiation and functions of immune cells (Powell et al., 2012). Lysosomal localization of key signal comp orients is critical for mTORCI activati on: mTORCI activation requires co-localization of activated Rheb and mTORCI to the lysosome membrane (Buerger et al., 2006). Signals in eluding growth factors, cellular stresses and energy levels act on the disruption the formation of tuberous sclerosis complex (TSC) complex, comprised of TSC1, TSC2 and TBC1D7, which leads to the translocation and activation of Rheb on the lysosome membrane (Dibble et al., 2012). In response to nutrient levels, specifically the availability of amino acids and glucose (Efeyan et al., 2013), mTORCI is recruited to the lysosomal surface by Rag GTPases that are heterodimers of RagA or RagC bound to RagB or RagD. Multiple protein complexes have been implicated in regulation of mTORCI upon nutrient sensing including Ragulator, GATOR1, GATOR2, KICSTOR and vacuolar ATPases (Wolfson et al., 2017). Vacuolar ATPases are large multiple-protein complexes that acidify the lysosome and may mediate additional functions independent of their proton pump activity (Nishi and Forgac, 2002).

关键词： ATP6V0d2 mediates leucine-induced mTORCI activation macrophages

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再生块体混凝土板的冲切性能试验研究

华南理工大学学报（自然科学版） 2019年第8期47卷 1-8页

作者：吴波陈宇菲华南理工大学亚热带建筑科学国家重点实验室

开展了8块再生块体混凝土板的冲切试验,探讨了废旧混凝土块体、配筋率、板厚、板跨等参数对板冲切性能的影响,考察了不同规范预测再生块体混凝土板冲切承载力的有效性,建议给出了相应的修正系数.结果表明:当废旧混凝土强度低于新混凝土... 详细信息

开展了8块再生块体混凝土板的冲切试验,探讨了废旧混凝土块体、配筋率、板厚、板跨等参数对板冲切性能的影响,考察了不同规范预测再生块体混凝土板冲切承载力的有效性,建议给出了相应的修正系数.结果表明:当废旧混凝土强度低于新混凝土时,再生块体混凝土板的初始刚度与常规混凝土板几乎相同,但冲切承载力略有降低;配筋率和冲跨比保持不变时,为提高板的冲切承载力,增大板厚远比减小板跨(即减小柱距)更为有效;在板的冲切承载力计算中,合理考虑配筋的影响是十分必要的,冲跨比较小时现行规范的冲切承载力计算公式有待进一步完善;为使再生块体混凝土板的冲切承载力预测结果具有与常规混凝土板相似的安全性,建议对前者乘以0.95的修正系数.

关键词：混凝土板废旧混凝土块体冲切试验冲切承载力