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A review of advances in tribology in 2020–2021

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Friction 2022年第10期10卷 1443-1595页

作者： yonggang MENG Jun Xu liran MA Zhongmin JIN Braham PRAKASH Tianbao MA Wenzhong WANG State Key laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China School of Mechanical Engineering Southwest Jiaotong UniversityChengdu 610031China School of Mechanical Engineering University of LeedsLeeds LS29JTUK School of Mechanical and Vehicle Engineering Beijing Institute of TechnologyBeijing 100082China

Around 1,000 peer-reviewed papers were selected from 3,450 articles published during 2020–2021,and reviewed as the representative advances in tribology research *** survey highlights the development in lubrication,wear and surface engineering,biotribology,high temperature tribology,and computational tribology,providing a show window of the achievements of recent fundamental and application researches in the field of tribology.

关键词： lubrication friction wear surface engineering tribology biotribology high temperature computer simulations

EXPERIMENTAl APPlICATION OF A THINNING SCHEME FOR THE ASSIMIlATION OF SuRFACE OBSERVATION DATA IN GRAPES-3DVAR

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Journal of Tropical Meteorology 2018年第3期24卷 334-345页

作者： ZHAO Hong l.u Yin luhe Meteorological Bureau Nanjing 211599 China Jiangsu Meteorological Observation Center Nanjing 210009 China Jiangsu Institute of Meteorological Sciences Nanjing 210009 China

To reduce the spatial correlation of representation error in observations and computational complexity, we propose a thinning scheme that can extract typical observations within a certain range. This scheme is applied to the Global/Regional Assimilation and Prediction System(GRAPES) with three-dimensional variation(3 DVAR) to study the effect of the thinning radius on the assimilation results. The assimilation experiments indicate that when the ratio of the model resolution to the observational resolution is 1:3, the simulated results for precipitation are relatively good and have a relatively high equitable threat score(ETS). Moreover, the analysis errors in the temperature and the specific humidity are the smallest, the dependence of the norm gradient vector of the objective function on the number of iterations is slow, gentle, and close to 0, and the minimization results in improved conditions.

关键词： thinning typical observation data assimilation

High-power passively Q-switched Nd:GdVO_4 laser with a reflective graphene oxide saturable absorber

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Chinese Optics letters 2019年第2期17卷 41-45页

作者： Taijin Wang Jiang Wang yonggang Wang Xiguang Yang Sicong l.u Ruidong lü Zhendong Chen School of Physics and Information Technology Shaanxi Normal University

A single output Q-switched Nd:GdVO4 laser with a reflective graphene oxide(GO) saturable absorber was demonstrated. The shortest pulse duration in the Q-switched laser is 115 ns, and the output power ranges from1.23 W at 1.71 MHz to 2.11 W at 2.50 MHz when the pump power rises from 7.40 to 10.90 W with the utilization of GO langmuir–Blodgett(lB) films based on the convenient and low-cost lB technique. To the best of our knowledge, it is the highest output power in a Q-switched laser with a GO saturable absorber.

关键词： High-power passively Q-switched

Characterization and Three-dimensional Structural Modeling of Humic Acid via Molecular Mechanics and Molecular Dynamic Simulation

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Chemical Research in Chinese universities 2013年第6期29卷 1180-1184页

作者： ZHAO Nan l.u) Yi-zhong lI Guang-jun College of Resources and Environmental Sciences China Agricultural University Beijing 100193 P.R.China School of Chemistry and Environment Beijing University of Aeronautics and AstronauticsBeijing 100191 P.R.China

The humic acid（HA） sample obtained from the al.uvial soil was characterized by elemental composition, pyrolysis gas chromatography-mass spectrometry（Py-GC-MS） and solid-state 13C nuclear magnetic resonance （13C NMR） spectroscopy. There is high fat content and a few nitrogen-containing functional groups in HA. Py-GC-MS demonstrates the characterization and structural identification of HA. One long list of identified pyrolysis products was proposed for the construction of conceptual model of HA. Solid-state 13C NMR data indicate there are higher values of alkyl-C, O-alkyl-C and aryl-C in HA. The elemental composition, structural carbon distribution and l3C NMR spectroscopy of simulated HA are consistent with those of experimental HA. HyperChem was used to simulate the three-dimensional molecular structure of the monomer, which was optimized by the molecular mechanics of the optimized potential for liquid simulations（OPlS） force field and molecular dynamics simulation to get the stable and balanced conformation. The deprotonation process study depicts that the degree of ionization of HA gets deeper, while the electronegativity of HA and the energy of van der Waals（vdW） increase. Moreover, the 3D structure of humic acid with -4 charges is the most stable. The deprotonation process is an endothermic process.

关键词： Al.uvial soil Humic acid Conceptual model Elemental analysis Pyrolysis gas chromatography-mass spectrometry(Py-GC-MS) 13C nuclear magnetic resonance(13C NMR) Molecular simulation Three-dimensional structure Optimized potential for liquid simulatio

In search of a pan-coronavirus vaccine:next-generation vaccine design and immune mechanisms

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Cel.ular & Molecular Immunology 2024年第2期21卷 103-118页

作者： S.Cankat M.u.Demael l.Swadling Division of Infection and Immunity Institute of Immunity and TransplantationUniversity College LondonPears BuildingLondon NW32PPUK

Members of the coronaviridae family are endemic to human populations and have caused several epidemics and pandemics in recent *** this review,we will discuss the feasibility of and progress toward the ultimate goal of creating a pan-coronavirus vaccine that can protect against infection and disease by all members of the coronavirus *** will detail the unmet clinical need associated with the continued transmission of SARS-CoV-2,MERS-CoV and the four seasonal coronaviruses(HCoV-OC43,Nl63,HKu1 and 229E)in humans and the potential for future zoonotic *** will highlight how first-generation SARS-CoV-2 vaccines and natural history studies have greatly increased our understanding of effective antiviral immunity to coronaviruses and have informed next-generation vaccine *** will then consider the ideal properties of a pan-coronavirus vaccine and propose a blueprint for the type of immunity that may offer ***,we will describe a subset of the diverse technologies and novel approaches being pursued with the goal of developing broadly or universally protective vaccines for coronaviruses.

关键词： Vaccine Coronavirus Cross-reactive immunity Cross-protection universal

Influence of ageing on oil degradation and gassing tendency under high-energy electrical discharge faults for mineral oil and synthetic ester

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High Voltage 2020年第6期5卷 731-738页

作者： l.loiselle u.Mohan Rao I.Fofana Research Chair on the Aging of Power Network Infrastructure(ViAHT) Universitédu QuébecàChicoutimiChicoutimiQCG7H 2B1Canada

In this work, mineral oil and synthetic esters were selected at different ageing factors (based on acidity values). Fresh and aged oils have been subjected to high-energy discharges (repeated 100 breakdowns) to simulate electric faults of highly vulnerable intensity. The intent of this work is to understand the influence of high-energy electric faults on oil degradation and gassing tendency at different ageing conditions. In this study, the influence of the high-energy discharges on degradation and gassing tendency at different ageing factors is reported for mineral oil and synthetic esters. Oil degradation is reported by adopting ultraviolet spectroscopy, turbidity and particle counter as per american society for testing and materials (ASTM) standard test methods. Gassing tendencies and fault gas analysis are understood by dissolved the gas analysis using Duval's triangle and Duval's pentagon methods for mineral and non-mineral oils. It is found that the influence of high-energy discharges on oil degradation is higher in mineral oils to that of the synthetic esters. The intensity of the gassing tendency is higher for ester fluids;however, as per the Duval methods, the faulty conditions are at lower levels as compared to mineral oils.

关键词： synthetic energy high

Experiment and modelling of texture and sliding direction dependence on finger friction behavior

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Friction 2024年第9期12卷 1955-1968页

作者： Yuanzhe lI Xue ZHOu Pengpeng BAI Zhonghuan XIANG yonggang MENG liran MA Yu TIAN State Key laboratory of Tribology in Advanced Equipment School of Mechanical EngineeringTsinghua UniversityBeijing 100084China

Humans rely on their fingers to sense and interact with external *** the tribological behavior between finger skin and object surface is crucial for various fields,including tactile perception,product appearance design,and electronic skin *** describing finger frictional behavior is always challenging,given the complex structure of the *** this study,the texture and sliding direction dependence of finger skin friction was quantified based on explicit mathematic *** proposed double-layer model of finger skin effectively described the nonlinear elastic response of skin and predicted the scaling-law of effective elastic modulus with contact ***,the skin friction model on textured surface considering adhesion and deformation factors was *** revealed that adhesive term dominated finger friction behavior in daily life,and suggested that object texture size mainly influenced friction-induced vibrations rather than the average friction *** with digital image correlation(DIC)technique,the effect of sliding direction on finger friction was *** was found that the anisotropy in finger friction was governed by the finger’s ratchet pawl structure,which also contributes to enhanced stick-slip vibrations in the distal sliding *** proposed friction models can offer valuable insights into the underlying mechanism of skin friction under various operating conditions,and can provide quantitative guidance for effectively encoding friction into haptics.

关键词： finger friction tactile perception tribological model textured surface sliding direction

NFKB signaling regulates embryonic and adult neurogenesis

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Frontiers in Biology 2012年第4期7卷 277-291页

作者： yonggang ZHANG Wenhui Hu Department of Neuroscience Temple University School of Medicine Philadelphia PA 19140 USA

Both embryonic and adult neurogenesis involves the self-renewal/proliferation, survival, migration and lineage differentiation of neural stem/progenitor cells. Such dynamic process is tightly regulated by intrinsic and extrinsic factors and complex signaling pathways. Misregulated neurogenesis contributes much to a large range of neurodevelopmental defects and neurodegenerative diseases. The signaling of NFKB regulates many genes important in inflammation, immunity, cell survival and neural plasticity. During neurogenesis, NFKB signaling mediates the effect of numerous niche factors such as cytokines, chemokines, growth factors, extracel.ular matrix molecules, but also cross- talks with other signaling pathways such as Notch, Shh, Wnt/l]-catenin. This review summarizes current progress on the NFttB signaling in all aspects of neurogenesis, focusing on the novel role of NFKB signaling in initiating early neural differentiation of neural stem cells and embryonic stem ceils.

关键词： neural stem cells transcriptional factors NFr.B neurogenesis embryonic stem cells signal transduction

SHRIMP Zircon u-Pb Chronology and Geochemistry of the Henglingguan and Beiyu Granitoids in the Zhongtiao Mountains,Shanxi Province

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Acta Geologica Sinica(English Edition) 2006年第6期80卷 912-924页

作者： Yu Shengqiang l.u Shuwen TIAN Wei lI Qiugen FENG yonggang The Key laboratory of Orogenic Belts and Crustal Evolution Ministry of EducationSchool of Earth and Space SciencesPeking UniversityBeijing 100871

Henglingguan and Beiyu metamorphic granitoids, distributed in the northwest of the Zhongtiaoshan Precambrian complex, comprise trondhjemites and calc-alkaline monzogranites, displaying intrusive contacts with the Archean Zhaizi TTG gneisses. And the Beiyu metamorphic granitoids consist mainly of trondhjemites, distributed at the core of the Hujiayu anticline fold. New SHRIMP zircon u-Pb dating data show that the weighted mean ^207pb/^206pb ages are 2435.9 Ma and 2477 Ma for the Henglingguan metamorphic calc-alkaline monzogranites and Beiyu metamorphic trondhjemites, respectively, and reveal -2600 Ma inherited core in magmatic zircons. Whole-rock geochemical data indicate that all the Henglingguan and Beiyu metamorphic trondhjemites and calc- alkaline monzogranites belong to the metaluminous medium- and high-potassium calc-alkaline series. These rocks are characterized by relatively high total alkali contents (Na2O+K2O, up to 9.08%), depleted Nb, Ta, P and Ti, and right-declined REE patterns with moderate to high lREEs/HREEs fractionation (the mean ratio of (la/Yb)n = 25). The Henglingguan and Beiyu metamorphic trondhjemites display negative Rb, Th and K anomalies in the multi-dement spider diagrams normalized by primitive mantle. Sm-Nd isotopic data reveal that these granitoids have initial εNd(t) =-1.2 to +2.4 and Nd depleted mantle model ages of TMD = 2622 Ma-2939 Ma. All these geochemical features indicate that these granitoids were formed in an continent-marginal arc, and the trondhjemites mainly originated from partial melting of juvenile basaltic materials and, howbeit, the Henglingguan metamorphic calc-alkaline monzogranites derived from recycling of materials in the ancient crust under a continent-marginal arc. The granitic magma underwent contamination and fractional crystallization during their formation.

关键词： Henglingguan and Beiyu granitoids SHRIMP zircon u-Pb geochronology geochemistry Sm-Nd isotopes continent-marginal arc Shanxi