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Numerical and Experimental Analysis of the Aerodynamic Torque for Axle-Mounted Train Brake Discs

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Fluid Dynamics & Materials Processing 2024年第8期20卷 1867-1882页

作者： Nan Liu Chen Hong Xinchao Su xing Jin Chen jiang Yuqi Shi Bingkun Wang Brake System Laboratory CRCC(Qingdao)Vehicle Inspection Station Co.Ltd.Qingdao266031China Brake System Laboratory CRRC Qingdao Sifang Rolling Stock Research Institute Co.Ltd.Qingdao266031China The State Key Laboratory of Heavy-Duty and Express High-Power Electric Locomotive Central South UniversityChangsha410075China Key Laboratory of Traffic Safety on Track of Ministry of Education School of Traffic&Transportation EngineeringCentral South UniversityChangsha410075China National&Local Joint Engineering Research Center of Safety Technology for Rail Vehicle Changsha410075China

As the velocity of a train increases,the corresponding air pumping power consumption of the brake discs increases *** the present experimental study,a standard axle-mounted brake disc with circumferential pillars was analyzed using a 1:1 scale model and a test rig in a wind *** particular,three upstream velocities were selected on the basis of earlier investigations of trains operating at 160,250,and 400 km/h,***,3D steady computational fluid dynamics(CFD)simulations of the flow field were conducted to compare with the wind tunnel test *** results for a 3-car train at 180 km/h demonstrated:(1)good agreement between the air resistance torques obtained from the wind tunnel tests and the related numerical results,with differences ranging from 0.95%to 5.88%;(2)discrepancies ranging from 3.2 to 3.8 N·m;(3)cooling ribs contributing more than 60%of the air resistance torque;(4)the fast rotation of brake discs causing a significantly different flow field near the bogie area,resulting in 25 times more air pumping power loss than that obtained in the stationary brake-disc case.

关键词： Axle-mounted train brake disc aerodynamic torque wind tunnel test numerical simulation

Correlating dynamic relaxation and viscoelasticity in metallic glasses

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 81-90页

作者： GuangHui xing Qi Hao Fan Zhu Yun-jiang Wang Yong Yang Hidemi Kato Eloi Pineda Si Lan JiChao Qiao School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'an 710072China State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China Department of Mechanical Engineering College of EngineeringCity University of Hong KongHong Kong 999077China Department of Materials Science and Engineering College of EngineeringCity University of Hong KongHong Kong 999077China Institute for Materials Research Tohoku UniversitySendai 980-8577Japan Department of Physics Institute of Energy TechnologiesUniversitat Politècnica de CatalunyaBarceona 9Spain School of Material Science and Engineering Herbert Gleiter Institute of NanoscienceNanjing University of Science and Technology.Nanjing 210094China State Key Laboratory of Clean and Efficient Turbomachinery Power Equipment Northwestern Polytechnical UniversityXi'an 710072China

Relaxation dynamics,essential for the structural evolution of non-equilibrium systems like glassy materials,remain ***,we explore relaxation dynamics and viscoelastic properties in three types of metallic glasses with distinctβrelaxation *** systems with significantβrelaxation,stress relaxation and creep experiments reveal a transition from two-step to one-step relaxation with rising ***,such a phenomenon is absent in systems with weakerβ*** model the two-step relaxation process using a double Kohlrausch-Williams-Watts equation,and the obtained relaxation times elegantly adhere to the Arrhenius *** combining fitted activation energies with theoretical analysis,we conclusively attribute these relaxation processes toβrelaxation andαrelaxation,***,we analyze the relaxation time spectra of two processes and establish a comprehensive picture linking dynamic relaxation with *** study provides new strategies for probing the complex relaxation behaviors of glasses from the perspective of viscoelasticity.

关键词： creep relaxation glasses

Advanced rare earth tantalate RETaO_(4)(RE=Dy,Gd and Sm) with excellent oxygen/thermal barrier performance

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Journal of Rare Earths 2024年第8期42卷 1595-1603,I0007页

作者： Jun Wang Jianyu Li Chunyu jiang Jianbo Song xing Yang Xiaolong Ma Kailiang Luo Peng Wu Xiaoyu Chong Jing Feng Faculty of Material Science and Engineering Kunming University of Science and TechnologyKunming650093China Shanxi Tianxuan Coating Technology Co. LtdXi'an710000China

Thermal barrier coatings(TBCs) materials with lowered the rmal and oxygen ion conductivity can provide thermal and oxidative protection for high te mperature hot-end components in aero nautical engines and gas turbines,The rare-earth tantalate RETaO_(4)(RE=Dy,Gd and Sm) ceramics with monoclinic(m) phase were successfully synthesized via spark plasma *** vacancies responsible for the thermal and oxygen ion conductivities of RETaO_(4) were demonstrated by atomic-resolution energy dispersive Xray and X-ray photoelectron *** the three samples,DyTaO_(4) has excellent oxygen/thermal barrier *** to the current service thermal barrier coating material ZrO_(2)-8 wt% Y_(2)O_(3)(8 YSZ),DyTaO_(4) has an ultra-low oxygen ion conductivity benefiting from low oxygen vacancy concentration and strong stretching force *** intrinsic thermal conductivity of DyTaO_(4)is 68.2% less than that of 8 ***,the thermal expansion rate curves indicate that the phase transformation does not happen from room te mperature to 1200℃.The above results demonstrate that high-growth rate the rmally grown oxide can be retarded by creating dense DyTaO_(4) coating with lowered thermal and oxygen ion conductivity.

关键词： Thermal barrier coatings Rare earths Oxygen vacancies Thermal conductivity Oxygen ion conductivity

Simultaneous Bulk-and Surface-initiated Living Polymerization Studied with a Heterogeneous Stochastic Reaction Model

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Chinese Journal of Polymer Science 2024年第3期42卷 364-372,I0008页

作者： Jia-Shu Ma Zhi-Ning Huang Jia-Hao Li Bang-Ping jiang Yan-Da Liao Shi-Chen Ji xing-Can Shen State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources(Ministry of Education of China)School of Chemistry and Pharmaceutical SciencesGuangxi Normal UniversityGuilin 541004China School of Computer Science and Engineering&School of Software Guangxi Normal UniversityGuilin 541004China

To better characterize the properties of surface-initiated polymers, simultaneous bulk-and surface-initiated polymerizations are usually carried out by assuming that the properties of the surface-initiated polymers resemble those of the bulk-initiated polymers. Through a Monte Carlo simulation using a heterogeneous stochastic reaction model, it was discovered that the bulk-initiated polymers exhibit a higher molecular weight and a lower dispersity than the corresponding surface-initiated polymers, which indicates that the equivalent assumption is invalid. Furthermore, the molecular weight distributions of the two types of polymers are also different, suggesting different polymerization mechanisms. The results can be simply explained by the heterogeneous distributions of reactants in the system. This study is helpful to better understand surface-initiated polymerization.

关键词： Surface-initiated polymerization Polymer brush Stochastic reaction model Heterogeneous polymerization Simultaneous polymerization

Potassium alleviated high nitrogen-induced apple growth inhibition by regulating photosynthetic nitrogen allocation and enhancing nitrogen utilization capacity

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Horticultural Plant Journal 2024年第1期10卷 1-14页

作者： Xinxiang Xu Guangyuan Liu Jingquan Liu Mengxue Lyu Fen Wang Yue xing Hao Meng Min Li Yu jiang Ge Tian Zhanling Zhu Yuanmao jiang Shunfeng Ge State Key Laboratory of Crop Biology College of Horticulture Science and EngineeringShandong Agricultural UniversityTai'anShandong 271018China Key Laboratory of Biochemistry and Molecular Biology in Universities of Shandong College of Biological and Agricultural EngineeringWeifang UniversityWeifangShandong 261061China

There is a close relationship between potassium(K)and nitrogen(N).However,the roles of K under high N conditions remain *** a hydroponics approach,we monitored the morphological,physiological,and molecular changes in M9T337 apple(Malus domestica)rootstocks under different nitrate(10 and 30 mmol·L^(-1)NO_(3)^(-))and K supply(0.5,6,10,and 20 mmol·L_(-1)K^(+))*** revealed that high nitrate inhibited the root growth of M9T337 rootstocks,downregulated the expressions of K transporter genes(MdPT5,MdHKT1,and MdATK1),and reduced the net NO3-and K+influx at the surface of roots,thereby resulting in an N/K imbalance in *** investigation showed that 10 mmol·L^(-1)K increased the activity of N metabolic enzymes(NR,GS,NiR,and GOGAT),upregulated the expressions of genes related to nitrate uptake and transport(MdNRT1.1,MdNRT1.2,MdNRT1.5,and MdNRT2.4),promoted15N transport from the roots to the shoots,optimized leaf N distribution,and improved photosynthetic N utilization efficiency under high nitrate *** results suggest that the negative effects of high nitrate may be related to the N/K imbalance and that reducing N/K in plants by increasing K supply level can effectively alleviate the inhibition of N assimilation by high nitrate stress.

关键词： Apple rootstock K level High nitrate stress N metabolism ^(15)N

KAT7/HMGN1 signaling epigenetically induces tyrosine phosphorylation-regulated kinase 1A expression to ameliorate insulin resistance in Alzheimer’s disease

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World Journal of Psychiatry 2024年第3期14卷 445-455页

作者： Qun-Shan Lu Lin Ma Wen-Jing jiang xing-Bang Wang Mei Lu Department of Geriatric Medicine Qilu Hospital of Shandong UniversityJinan 250012Shandong ProvinceChina Key Laboratory of Cardiovascular Proteomics of Shandong Province Qilu Hospital of Shandong UniversityJinan 250012Shandong ProvinceChina

BACKGROUND Epidemiological studies have revealed a correlation between Alzheimer’s disease(AD)and type 2 diabetes mellitus(T2D).Insulin resistance in the brain is a common feature in patients with T2D and ***7 is a histone acetyltransferase that participates in the modulation of various *** To determine the effects of KAT7 on insulin patients with *** APPswe/PS1-dE9 double-transgenic and db/db mice were used to mimic AD and diabetes,*** in vitro model of AD was established by Aβ*** resistance was induced by chronic stimulation with high insulin *** expression of microtubule-associated protein 2(MAP2)was assessed using *** protein levels of MAP2,Aβ,dual-specificity tyrosine phosphorylation-regulated kinase-1A(DYRK1A),IRS-1,p-AKT,total AKT,p-GSK3β,total GSK3β,DYRK1A,and KAT7 were measured via western *** of reactive oxygen species(ROS),malondialdehyde(MDA),and SOD activity was measured to determine cellular oxidative *** cytometry and CCK-8 assay were performed to evaluate neuronal cell death and proliferation,*** RNA levels of KAT7 and DYRK1A were examined using quantitative PCR.A chromatin immunoprecipitation assay was conducted to detect H3K14ac in *** KAT7 expression was suppressed in the AD *** of KAT7 decreased Aβaccumulation and MAP2 expression in AD ***7 overexpression decreased ROS and MDA levels,elevated SOD activity in brain tissues and neurons,and simultaneously suppressed neuronal ***7 upregulated levels of p-AKT and p-GSK3βto alleviate insulin resistance,along with elevated expression of ***7 depletion suppressed DYRK1A expression and impaired H3K14ac of ***1 overexpression recovered DYRK1A levels and reversed insulin resistance caused by KAT7 *** We determined that KAT7 overexpression recovered insulin sensitivity in AD by recruiting HMGN1 to enhance DYRK1A acetylati

关键词： Alzheimer's disease Diabetes Insulin resistance KAT7 Dual-specificity tyrosine phosphorylation-regulated kinase-1A HMGN1

Pollutant emissions from biomass burning:A review on emission characteristics,environmental impacts,and research perspectives

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Particuology 2024年第2期85卷 296-309页

作者： Ke jiang Ran xing Zhihan Luo Wenxuan Huang Fan Yi Yatai Men Nan Zhao Zhaofeng Chang jinfeng Zhao Bo Pan Guofeng shen College of Urban and Environmental Sciences Peking UniversityBeijing100871China Beijing Key Lab Plant Resources Research and Development Beijing Technology and Business UniversityBeijing100048China College of Ecology and Environment Zhengzhou UniversityZhengzhou450001China Facultyof Environmental Sciences and Engineering Kunming University of Science and TechnologyYunnan Provincial Key Laboratoryof Soil Carbon Sequestration and Pollution ControlKunming650500China Institute of Carbon Neutrality Peking UniversityBeijing100871China

Biomass is one most abundant resource on the earth providing important energies in support of so-cioeconomic development in many *** of biomass fuels comprises to nearly 10%of the total energy from anthropogenic combustion processes:however,as the burning is usually incomplete,this process yields products of incomplete combustion posing consequently significant impacts on air quality,human health,and climate ***,we analyzed spatiotemporal characteristics in intentional and unintentional biomass burning from different sectors,discussed impacts of biomass burning emissions on indoor and outdoor air quality,and consequent influences on human *** global total con-sumption amount of biomass including both natural and anthropogenic sources was approximately 7900 Tg in 2019,with significantly large regional and sectorial discrepancies among ***,anthropogenic biomass burning amounts increased gradually,but notably in some developing countries like China residential consumption of biomass fuels,as one large sector of biomass use,decreased over *** biomass consumption needs to be accurately *** are relatively rich datasets of pollutant emission factors from biomass burning,including laboratory and field tests,but still large variations exit and contribute substantially to the uncertainty in emission *** pri-mary PM2.5,black carbon and organic carbon emissions from biomass burning were about 51,4.6,and 29 Tg,respectively,contributing to nearly 70%,55%,and 90%of the total emission from all sources,and emissions from the residential sector and open fires are major *** carbon emissions from biomass burning attracts growing interests but available studies adopted different methodologies challenging the comparability of those *** burning emissions polluted not only ambient air but more severely indoor air quality,adversely affecting human *** studies that should be emphasiz

关键词： Biomass burning Carbonaceous aerosol Emission Air quality Human health

A quadrivalent norovirus vaccine based on a chimpanzee adenovirus vector induces potent immunity in mice

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Virologica Sinica 2024年第4期39卷 675-684页

作者： Yihua jiang Lingjin Sun Nan Qiao Xiang Wang Caihong Zhu Man xing Hui Liu Ping Zhou Dongming Zhou Department of Pathogen Biology School of Basic Medical SciencesTianjin Medical UniversityTianjin300070China Shanghai Public Health Clinical Center Fudan UniversityShanghai201508China R&D Centre Chengdu Kanghua Biological Products Co.LtdChengdu610000China Institut Pasteur of Shanghai Chinese Academy of SciencesShanghai200031China

Norovirus(NoV)infection is a major cause of gastroenteritis *** virus poses great challenges in developing vaccines with broad immune protection due to its genetic and antigenic *** date,there are no approved NoV vaccines for clinical ***,we aimed to develop a broad-acting quadrivalent NoV vaccine based on a chimpanzee adenovirus vector,AdC68,carrying the major capsid protein(VP1)of noroviral GI and GII *** to intramuscular(i.m.),intranasal(i.n.),or other prime-boost immunization regimens(i.m.t i.m.,i.m.t i.n.,i.n.t i.m.),AdC68-GI.1-GII.3(E1)-GII.4-GII.17(E3),administered via i.n.t *** higher titers of serum IgG antibodies and higher IgA antibodies in bronchoalveolar lavage fluid(BALF)and saliva against the four homologous VP1s in *** also significantly stimulated the production of blocking antibodies against the four *** response to re-stimulation with virus-like particles(VLP)-GI.1,VLP-GII.3,VLP-GII.4,and VLP-GII.17,the quadrivalent vaccine administered according to the i.n.t *** effectively triggered specific cell-mediated immune responses,primarily characterized by IFN-γ***,the preparation of this novel quadrivalent NoV vaccine requires only a single recombinant adenovirus to provide broad preventive immunity against the major GI/GII epidemic strains,making it a promising vaccine candidate for further development.

关键词： Norovirus(NoV) Quadrivalent vaccine Adenovirus vector

Enhancing thermoelectric performance of p-type SnTe through manipulating energy band structures and decreasing electronic thermal conductivity

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Rare Metals 2024年第7期43卷 3232-3241页

作者： Xin Qian Hao-Ran Guo Jia-Xin Lyu Bang-Fu Ding xing-Yuan San Xiao Zhang jiang-Long Wang Shu-Fang Wang Hebei Key Lab of Optic-Electronic Information and Materials College of Physics Science and TechnologyHebei UniversityBaoding 071002China College of Electron and Information Engineering Hebei UniversityBaoding 071002China Research Institute for Frontier Science Beihang UniversityBeijing100191China

SnTe has received considerable attention as an environmentally friendly alternative to the representative thermoelectric material of ***,excessive hole carrier concentration in SnTe results in an extremely low Seebeck coefficient and high thermal conductivity,which makes it exhibit relatively inferior thermoelectric *** this work,the thermoelectric performance of p-type SnTe is enhanced through regulating its energy band structures and reducing its electronic thermal conductivity by combining Bi doping with CdSe ***,the carrier concentration of SnTe is successfully suppressed via Bi doping,which significantly decreases the electronic thermal ***,the convergence and flattening of the valence bands by alloying CdSe effectively improves the effective mass of SnTe while restraining its carrier ***,a maximum figure of merit(ZT) of~ 0.87 at 823 K and an average ZT of~ 0.51 at 300-823 K have been achieved in Sn_(0.96)Bi_(0.04)Te-5%*** results indicate that decreasing the electronic thermal conductivity is an effective means of improving the performance of thermoelectric materials with a high carrier concentration.

关键词： Thermoelectric materials SnTe Energy band structure Electronic thermal conductivity ZT value