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Photoinduced superlubricity on TiO_(2) surfaces

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Friction 2024年第3期12卷 428-438页

作者： Ke HAN Liran MA yu tian Jianbin LUO State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China Received:16 September 2022/Revised:28 October 2022/Accepted:27 December 2022The author(s)2022.

Superlubricity control is of great interest in both industry and scientific research,and several methods have been proposed to achieve this goal.In this work,ultraviolet(UV)light was introduced into titanium dioxide(TiO_(2))and silicon nitride(Si_(3)N_(4))tribosystems to accomplish photoinduced superlubricity.The friction coefficients(COFs)between Si_(3)N_(4) balls and TiO_(2) plates in the mixtures of sulfuric acid(H^(2)SO_(4))solution and glycerol solution were obviously reduced,and the system entered the superlubricity region(COF<0.01)after UV illumination at a speed of 56 mm/s.However,the COF was much larger without UV treatment than that with UV treatment.The formation of silica(SiO_(2))layers on the surfaces of Si_(3)N_(4) balls and the elastohydrodynamic effects were determined to be fundamental to the low friction in this experiment,and the enhancement of the combination between the TiO_(2) surface and the hydroxy group of glycerol by UV illumination was the key to the photoinduced superlubricity in this system.These findings showed one method for achieving superlubricity by introducing a light field that could be further applied to special working conditions.

关键词： light control friction superlubricity glycerol titanium dioxide(TiO_(2))

In memoriam:Shizhu Wen(1932-2023)

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Friction 2024年第7期12卷 1341-1346页

作者： Jianbin LUO Yonggang MENG yu tian State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversiyBejing 100084China

Professor Shizhu Wen,the winner of the 2015 Tribology Gold Medal,passed away due to illness on November 3,2023,at the age of 91.He was a professor of Tsinghua University,an academician of the Chinese Academy of Sciences,and the Honorary President of the Chinese Tribology Institute(CTI)from 1997 to 2007.Professor Wen was born in 1932 in Jiangxi Province of China and graduated from Tsinghua University in 1955,where he was awarded the Outstanding Graduate Gold Medal and then remained as an assistant professor at the University.Professor Wen was promoted to full professor in 1984.He had undertaken tribology research at the Imperial College London in 1979 and 1991.In 1985,he presided over the establishment of the State Key Laboratory of Tribology(SKLT)of Tsinghua University and served as the first director of the SKLT.

关键词： sided professor zhu

Co-pyrolysis of Sewage Sludge with Paint Sludge: Kinetics and Thermodynamic Analysis via Iso-conversional Methods

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Journal of Wuhan University of Technology(Materials Science) 2024年第3期39卷 716-727页

作者：周尚群赵青林 yu tian YAO Xiaojie State Key Laboratory of Silicate Materials for Architectures Wuhan University of TechnologyWuhan 430070China School of Mate-rials Science and Engineering Wuhan University of TechnologyWuhan 430070China

This study explored the synergistic interaction of sewage sludge(SS)and automotive paint sludge(PS)during co-pyrolysis for the optimized treatment of sewage sludge in cement kiln systems,utilizing thermogravimetric analysis(TGA)and thermogravimetric-mass spectrometry(TGA-MS).The result reveals the coexisting synergistic and antagonistic effects in the co-pyrolysis of SS/PS.The synergistic effect arises from hydrogen free radicals in SS and catalytic components in PS,while the main source of the antagonistic effect is that,during the mechanical mixing process,the SS/PS is converted from the particulate form into a dough-like rubbery which contributes to the film-forming effect,hindering the volatilization of volatile components.SS/PS co-pyrolysis reduces the yielding of tar production while increasing coke and gas.This study will provide some in-depth insights into the co-pyrolysis of SS/PS,and offer theoretical support for the subsequent research on the collaborative disposal processes in cement kilns.

关键词： sewage sludge co-pyrolysis automotive paint sludge evolved gas analysis

Hydration lubrication modulated by water structure at TiO2–aqueous interfaces

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Friction 2024年第4期12卷 591-605页

作者： Pingsu MA yuan LIU Ke HAN yu tian Liran MA State Key Laboratory of Tribology in Advanced Equipment Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China

The nature of solid-liquid interfaces is of great significance in lubrication.Remarkable advances have been made in lubrication based on hydration effects.However,a detailed molecular-level understanding is still lacking.Here,we investigated water molecule behaviors at the TiO2-aqueous interfaces by the sum-frequency generation vibrational spectroscopy(SFG-VS)and atomic force microscope(AFM)to elucidate the fundamental role of solid-liquid interfaces in lubrication.Combined contributions of water structures and hydration effects were revealed,where water structures played the dominant role in lubrication for TiO2 surfaces of varying hydrophilicity,while hydration effects dominated with the increasing of ion concentrations.Superior lubrication is observed on the initial TiO2 surfaces with strongly H-bonded water molecules compared to the hydrophilic TiO2 surfaces with more disordered water.The stable ordered water arrangement with strong hydrogen bonds and the shear plane occurring between the ordered water layer and subsequent water layer may play a significant role in achieving lower friction.More adsorbed hydrated molecules with the increasing ionic concentration perturb ordered water but lead to the enhancement of hydration effects,which is the main reason for the improved lubrication for both TiO2.This work provides more insights into the detailed molecular-level understanding of the mechanism of hydration lubrication.

关键词： hydration lubrication interfacial water structures hydration effects titanium dioxide(TiO2)

Selective adsorption of tetracycline by β-CD-immobilized sodium alginate aerogel coupled with ultrafiltration for reclaimed water

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Chinese Journal of Chemical Engineering 2024年第4期68卷 27-34页

作者： Xi Quan Jun Zhang Linlin Yin Wei Zuo yu tian State Key Laboratory of Urban Water Resource and Environment(SKLUWRE) School of EnvironmentHarbin Institute of TechnologyHarbin 150090China

In this work,a novel composite material based on β-cyclodextrin-immobilized sodium alginate aerogel(β-CD/NaAlg) was developed utilizing cross-linker of epichlorohydrin and applied as an adsorbent to remove tetracycline antibiotics from reclaimed wastewater.A series of characterizations were utilized to confirm the successful synthesis of the adsorbent and this β-CD/NaAlg presented a three-dimensional network at the nanoscale or microscale.Under optimal conditions(pH=4,t=8 h,β-CD:NaAlg=9,adsorbent dosage = 1.5 g·L-1),the maximum removal rate of β-CD/NaAlg to tetracycline was 70%.The adsorption behavior of tetracycline on β-CD/NaAlg conformed to the Freundlich isotherm model(R2=0.9977) and the pseudo-second-order kinetic model(R^(2)=0.9993).Moreover,the adsorbent still removed 55.3% of tetracycline after five cycles.Specially,the adsorbent was integrated with ultrafiltration to adsorb tetracycline antibiotics from simulated reclaimed wastewater,and the removal rate of tetracycline reached 78.9% within 2 h.The existence of Cr(Ⅵ) had a negligible impact on tetracycline removal,while the presence of humic acid exhibited a promoting effect.The possible adsorption mechanisms were also elucidated through X-ray photoelectron spectroscopy and density functional theory analysis.In summary,β-CD/NaAlg represents an environmentally friendly,efficient,and sustainable adsorbent for removing tetracycline antibiotics from reclaimed water.

关键词： b-CD/NaAlg aerogel Covalent grafting Tetracycline antibiotics Ultrafiltration Selective adsorption Reclaimed water

Soil disturbance evaluation of soft clay based on stress-normalized smallstrain stiffness

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 990-999页

作者： Yanguo Zhou yu tian Junneng Ye Xuecheng Bian yunmin Chen MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering Institute of Geotechnical EngineeringCenter for Hypergravity Experiment and Interdisciplinary ResearchZhejiang UniversityHangzhou310058China Ningbo Rail Transit Group Co. Ltd.Ningbo315010China

Soil disturbance includes the change of stress state and the damage of soil structure.The field testing indices reflect the combined effect of both changes and it is difficult to identify the soil structure disturbance directly from these indices.In the present study,the small-strain shear modulus is used to characterize soil structure disturbance by normalizing the effective stress and void ratio based on Hardin equation.The procedure for evaluating soil sampling disturbance in the field and the further disturbance during the subsequent consolidation process in laboratory test is proposed,and then validated by a case study of soft clay ground.Downhole seismic testing in the field,portable piezoelectric bender elements for the drilled sample and bender elements in triaxial apparatus for the consolidated sample were used to monitor the shear wave velocity of the soil from intact to disturbed and even remolded states.It is found that soil sampling disturbance degree by conventional thin-wall sampler is about 30%according to the proposed procedure,which is slightly higher than that from the modified volume compression method proposed by Hong and Onitsuka(1998).And the additional soil disturbance induced by consolidation in laboratory could reach about 50%when the consolidation pressure is far beyond the structural yield stress,and it follows the plastic volumetric strain quite well.

关键词： Natural clay Soil sample disturbance Shear wave velocity Small-strain shear modulus Hardin equation

Mitigated lattice distortion and oxygen loss of Li-rich layered cathode materials through anion/cation regulation by Ti^(4+)-substitution

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Chinese Chemical Letters 2024年第2期35卷 548-552页

作者： Kaicheng Zhang yu tian Xuanjin Chen Shan Hu Zelang Jian State Key Laboratory of Advanced Technology for Materials Synthesis and Processing School of Materials Science and EngineeringWuhan University of TechnologyWuhan 430070China

Lithium-rich layered cathode material(LLM)can meet the requirement of power lithium-ion energy storage devices due to the great energy density.However,the de/intercalation of Li+will cause the irreversible loss of lattice oxygen and trigger transition metal(TM)ions migrate to Li+vacancies,resulting in capacity decay.Here we brought Ti4+in substitution of TM ions in Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2),which could stabilize structure and expand the layer spacing of LLM.Moreover,optimized Ti-substitution can regulate the anions and cations of LLM,enhance the interaction with lattice oxygen,increase Ni^(3+) and Co^(3+),and improve Mn^(4+) coordination,improving reversibility of oxygen redox activation,maintaining the stable framework and facilitating the Li^(+) diffusion.Furthermore,we found 5%Ti-substitution sample delivered a high discharge capacity of 244.2 mAh/g at 50 mA/g,an improved cycling stability to 87.3%after 100 cycles and enhanced rate performance.Thereby Ti-substitution gives a new pathway to achieve high reversible cycle retention for LLMs.

关键词： Lithium-rich layered cathode material Ti-substitution Anion/cation regulation Structural stability Cycling stability

In patients who had a stroke or TIA, enlarged perivascular spaces in basal ganglia may cause future haemorrhagic strokes

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Stroke & Vascular Neurology 2024年第1期9卷 8-17,I0001-I0033页

作者： yu tian Mengxing Wang yuesong Pan Xia Meng Xingquan Zhao Liping Liu Yongjun Wang Yilong Wang Department of Neurology Beijing Tiantan HospitalCapital Medical UniversityBeijingChina Chinese Institute for Brain Research BeijingChina National Center for Neurological Diseases BeijingChina Advanced Innovation Center for Human Brain Protection Capital Medical UniversityBeijingChina China National Clinical Research Center for Neurological Diseases BeijingChina

Introduction It remains unclear whether enlarged perivascular spaces(EPVS)predict poor clinical outcomes in patients with acute ischaemic stroke(AIS)or transient ischaemic attack(TIA).Method Data were obtained from the Third China National Stroke Registry study.We estimated EPVS in basal ganglia(BG)and centrum semiovale(CSO)using a semiquantified scale(Grade from 0 to 4).Using Cox and logistic regression analyses,the associations of EPVS with 3-month and 1-year adverse outcomes(including recurrent stroke,ischaemic stroke,haemorrhagic stroke,combined vascular event,disability and mortality)were explored.Sensitivity analyses of any association of cerebral small vessel disease at baseline and development of a small arterial occlusion(SAO)were conducted.Result Among 12603 patients with AIS/TIA,median age was 61.7±11.6 years,and 68.2%were men.After adjusting for all potential confounders,frequent-to-severe BG-EPVS was associated with a decreased risk of recurrent ischaemic stroke(HR 0.71,95%CI 0.55 to 0.92,p=0.01)but an increased risk of haemorrhagic stroke(HR 1.99,95%CI 1.11 to 3.58,p=0.02)at 1 year after AIS/TIA,compared with none-to-mild BG-EPVS.Patients with frequent-to-severe CSO-EPVS had a decreased risk of disability(OR 0.76,95%CI 0.62 to 0.92,p=0.004)and all-cause death(HR 0.55,95%CI 0.31 to 0.98,p=0.04)within 3-month but not 1-year follow-ups,compared with those with none-to-mild BG-EPVS.Sensitivity analyses showed that both BG-EPVS(HR 0.43,95%CI 0.21 to 0.87,p=0.02)and CSO-EPVS(HR 0.58,95%CI 0.35 to 0.95,p=0.03)were associated with a decreased risk of subsequent ischaemic stroke in patients with SAO during 1-year follow-up.Conclusion BG-EPVS increased the risk of haemorrhagic stroke in patients already with AIS/TIA within 1 year.Therefore,caution is recommended when selecting antithrombotic agents for secondary stroke prevention in patients with AIS/TIA and more severe BG-EPVS.

关键词： patients haemorrhagic prevention

Evaluation and attribution of trends in compound dry-hot events for major river basins in China

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Science China Earth Sciences 2024年第1期67卷 79-91页

作者： Shaotang XIONG Tongtiegang ZHAO Chengchao GUO yu tian Fang YANG Wenlong CHEN Xiaohong CHEN Key Laboratory of Water Security Guarantee in Guangdong-Hong Kong-Marco Greater Bay Area of Ministry of Water Resources&Sun Yatsen University/Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Guangzhou 510275China China Institute of Water Resource and Hydropower Research Beijing 100038China Pearl River Hydraulic Research Institute Guangzhou 510611China

Concurrent compound dry and hot events(CDHEs)amplified more damange on the ecosystems and human society than individual extremes.Under climate change,compound dry and hot events become more frequent on a global scale.This paper proposes a mathematical method to quantitatively attribute changes of CDHEs to changes of precipitation,change in temperature and change in the dependence between precipitation and temperature.The attribution is achieved by formulating the total differential equation of the return period of CDHEs among Meta-gaussian model.A case study of China is devised based on monthly precipitation and temperature data during the period from 1921 to 2020 for 80 major river basins.It is found that temperature is the main driving factor of increases in CDHEs for 49 major river basins in China,except for the upper and middle reaches of the Yangtze River.In West China,precipitation changes drove the increase in CDHEs in 18 river basins(23%),particularly in parts of North Xinjiang,Qinghai and Gansu.On the other hand,dependence between precipitation and temperature dominated changes of CDHEs in 13 river basins(16%)of China with other factors,including parts of South China,East China and Northwestern China.Furthermore,changes in both the mean and spread of precipitation and temperature can also contribute to changes in CDHEs.

关键词： Climate extreme Compound dry and hot extreme Precipitation Temperature Return period