检索结果-南通市图书馆

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

高速动车组一系垂向半主动悬挂研究

力学学报 2024年第8期56卷 2423-2435页

作者：曹洪勇付彬王旭刘彬彬 di gialleonardo Egidio Bruni Stefano 中车青岛四方机车车辆股份有限公司技术中心山东青岛266111 米兰理工大学机械工程系意大利米兰20156

轻量化是轨道交通车辆发展的重要方向,可降低车辆能耗和运营维护成本.然而车体轻量化改变了车体弹性模态频率,增大了车体结构振动,造成车辆垂向舒适性恶化.提出了一系垂向半主动悬挂策略,即采用可变阻尼减振器替换原有一系垂向减振器,... 详细信息

轻量化是轨道交通车辆发展的重要方向,可降低车辆能耗和运营维护成本.然而车体轻量化改变了车体弹性模态频率,增大了车体结构振动,造成车辆垂向舒适性恶化.提出了一系垂向半主动悬挂策略,即采用可变阻尼减振器替换原有一系垂向减振器,通过对减振器阻尼特性进行实时控制,改善车体刚性和一阶弯曲模态振动.分析了车体刚性和弹性振动与构架振动的耦合关系,在此基础上对一系半主动悬挂的工作原理进行阐述.改进了经典的车辆垂向动力学模型,通过模型计算验证了车体和构架的多种耦合振动关系.对磁流变阻尼减振器的动态特性开展试验测试,建立了该减振器的动力学模型,实现对磁流变阻尼减振器非线性特性的准确预测.以国内某高速列车为原型,建立了完整的车辆动力学模型,并结合磁流变阻尼减振器动力学模型,对一系半主动悬挂的控制策略和应用效果展开研究,得到了两种易于工程应用的控制方法.结果表明一系半主动悬挂对车辆垂向振动,尤其是车体一阶弯曲振动具有显著的控制效果,可改善车辆垂向舒适性指标约30%.

关键词：一系半主动垂向舒适性车体一阶弯曲磁流变阻尼

Lower Continental Crusts Involved in the Alpine Orogeny:New Insight from the Santa Lucia Nappe Metasediments(Corsica,France)

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2024年第4期98卷 904-920页

作者： Chiara FRASSI Maria di ROSA luca PANDOLFI Michele MARRONI dipartimento di Scienze della Terra Universitàdi PisaVia Santa Maria 5356126 PisaItaly Istituto di Geoscienze e Georisorse IGG-CNRVia Moruzzi50124 PisaItaly

In the Alpine Corsica(France),the Santa Lucia Nappe represents a peculiar unit preserving the unique relicts of Paleozoic lower to medium continental *** consists of composite basement affected by Permian granulite facies metamorphic conditions unconformably covered by a Late Cretaceous clastic sequence(Tomboni Conglomerate and Tralonca Flysch)affected by polyphase deformation and *** this work,we present a new reconstruction of the deformation events registered by the Tralonca Flysch during the Alpine *** D1 phase was testified by rare isoclinal *** D2 phase produced a continuous foliation and a map-scale sheath-fold with a top-to-W sense of *** D3 phase produced E-verging non-cylindrical folds and S3 crenulation cleavage that is not associated to metamorphic *** present the first temperature-pressure-deformation(P-T-d)path for the Tralonca Flysch,demonstrating that the Santa Lucia Nappe underwent accretion and then first stage exhumation in the Alpine wedge during the D1 phase with pressure and temperature peaks both occurred under blueschist metamorphic *** D2 phase occurred at lower pressure-temperature conditions during a second stage *** pressure-temperaturedeformation path is comparable with those of the Lower Units(i.e.,the subducted continental units of Alpine Corsica)suggesting a common geodynamic history.

关键词： blueschist-facies metamorphism P-T-d path Santa Lucia Nappe Corsica Alpine orogeny

Tribological behavior of shape-specific microplate-enriched synovial fluids on a linear two-axis tribometer

在线全文

学校读者我要写书评

暂无评论

Friction 2024年第3期12卷 539-553页

作者： Agnese FRAGASSI Antonietta GRECO Martina di FRANCESCO luca CESERACCIU Aiman ABU AMMAR Israel DVIR Thomas Lee MOORE Haytam KASEM Paolo DECUZZI Laboratory of Nanotechnology for Precision Medicine Fondazione Istituto Italiano di TecnologiaGenova 16163Italy Department of Chemistry and Industrial Chemistry University of GenovaGenoa 16146Italy Materials Characterization Facility Istituto Italiano di TecnologiaGenova 16163Italy Department of Pharmaceutical Engineering Azrieli College of Engineering JerusalemJerusalem 9103501Israel Department of Mechanical Engineering Azrieli College of Engineering JerusalemJerusalem 9103501Israel

Nano-and micro-particles are being increasingly used to tune interfacial frictional properties in diverse applications,from friction modifiers in industrial lubrication to enhanced biological fluids in human osteoarthritic ***,we assessed the tribological properties of a simulated synovial fluid enriched with non-spherical,poly lactic-co-glycolic acid(PLGA)microparticles(μPL)that have been previously demonstrated for the pharmacological management of osteoarthritis(OA).Three different μPL configurations were fabricated presenting a 20μm×20μm square base and a thickness of 5μm(thin,5H μPL),10μm(10H μPL),and 20μm(cubical,20H μPL).After extensive morphological and physicochemical characterizations,the apparent Young’s modulus of the μPL was quantified under compressive loading returning an average value of~6 kPa,independently of the particle ***,using a linear two-axis tribometer,the static(μ_(s))and dynamic(μ_(d))friction coefficients of the μPL-enriched simulated synovial fluid were determined in terms of particle configuration and concentration,varying from 0(fluid only)to 6×10^(5) μPL/*** particle morphology had a modest influence on friction,possibly because the μPL were fully squeezed between two mating surfaces by a 5.8 N normal load realizing boundary-like lubrication ***,friction was observed to depend on the dimensionless parameterW,defined as the ratio between the total volume of the μPL enriching the simulated synovial fluid and the volume of the fluid *** coefficients of friction were documented to grow withWreaching a plateau of μ_(s)~0.4 and μ_(d)~0.15,already at Ω~2×10^(-3).Future investigations will have to systematically analyze the effect of sliding velocity,normal load,and rigidity of the mating surfaces to elucidate in full the tribological behavior of μPL in the context of osteoarthritis.

关键词： osteoarthritis microparticles tribology synovial fluid pin on plate

Nutrient restriction-activated Fra-2 promotes tumor progression via IGF1R in miR-15a downmodulated pancreatic ductal adenocarcinoma

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Signal Transduction and Targeted Therapy 2024年第3期9卷 1132-1146页

作者： Gian luca Rampioni Vinciguerra Marina Capece luca Reggiani Bonetti Giovanni Nigita Federica Calore Sydney Rentsch Paolo Magistri Roberto Ballarin Fabrizio di Benedetto Rosario distefano Roberto Cirombella Andrea Vecchione Barbara Belletti Gustavo Baldassarre Francesca Lovat Carlo M.Croce Department of Cancer Biology and Genetics and Comprehensive Cancer Center The Ohio State UniversityColumbus 43210 OHUSA Department of Clinical and Molecular Medicine Faculty of Medicine and PsychologySant’Andrea HospitalUniversity of Rome“Sapienza”Rome 00189Italy Department of diagnostic Clinic and Public Health MedicineUniversity of Modena and Reggio EmiliaModena 41100Italy Hepato-pancreato-biliary Surgery and Liver Transplantation Unit University of Modena and Reggio EmiliaModena 41100Italy division of Molecular Oncology Centro di Riferimento Oncologico di Aviano(CRO)Istituto di Ricovero e Cura a Carattere Scientifico(IRCCS)National Cancer InstituteAviano 33081Italy

Pancreatic ductal adenocarcinoma(PDAC)is a lethal disease,characterized by an intense desmoplastic reaction that compresses blood vessels and limits nutrient *** aggressiveness largely relies on its extraordinary capability to thrive and progress in a challenging tumor *** of the onco-suppressor miR-15a has been extensively documented in ***,we identified the transcription factor Fos-related antigen-2(Fra-2)as a miR-15a target mediating the adaptive mechanism of PDAC to nutrient *** report that the IGF1 signaling pathway was enhanced in nutrient deprived PDAC cells and that Fra-2 and IGF1R were significantly overexpressed in miR-15a downmodulated PDAC ***,we discovered that miR-15a repressed IGF1R expression via Fra-2 *** miR-15a-low context,IGF1R hyperactivated mTOR,modulated the autophagic flux and sustained PDAC growth in nutrient *** a genetic mouse model,Mir15aKO PDAC showed Fra-2 and Igf1r upregulation and mTOR activation in response to diet ***,nutrient restriction improved the efficacy of IGF1R inhibition in a Fra-2 dependent ***,our results point to a crucial role of Fra-2 in the cellular stress response due to nutrient restriction typical of pancreatic cancer and support IGF1R as a promising and vulnerable target in miR-15a downmodulated PDAC.

关键词： IGF1R Fra miR

Interpreting siliciclastic sedimentation in the upper Paleozoic Mulargia-Escalaplano Basin(Sardinia, Italy):influence of tectonics on provenance

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Palaeogeography 2024年第1期13卷 18-34页

作者： luca G.Costamagna Sara Criniti dipartimento di Scienze Chimiche e Geologiche Citadella UniversitariaBlocco A09042 Monserrato CAItaly dipartimento di Ingegneria dell'Ambiente Universita della Calabria87036 Arcavacata di Rende CSItaly

Late to post-Variscan molassic basins of Late Pennsylvanian-Permian age are exposed in Sardinia(Italy). Here, the compositional and stratigraphic evolution of the Mulargia-Escalaplano sedimentary basin(central Sardinia) has been investigated to highlight how the tectono-magmatic processes have influenced the sedimentation. Ruditic and arenitic samples were collected along well-characterized stratigraphic sections to provide a new insight into the impact of the tectono-magmatic processes on siliciclastic sedimentation. As a result, the conglomerates are mainly clast-supported, petromictic, and thus immature, with no defined maturity trend upwards. Nevertheless, pebble composition changes in times from Variscan basement pebble-rich to volcanic rock-rich, as a consequence of the basin widening and the dismantling and reworking of the coeval volcanic activity. The sandstone composition clearly changes from quartzolithic to feldspatholithic upwards, as a response to the same change of feeding and reworking of the volcanic rocks. Occasionally, interbedded quartzolithic arenites suggest exceptional floods carrying debris from the far borders of the basin. Also, the immature sandstone composition has been interpreted as being controlled by a continuous supply of fresh debris and to a rapid burial rate. In addition, the disappearance of metaradiolarite(lydite AA) Paleozoic grains in the sandstone mineral suite could represent a distinctive marker of a progressive unroofing of the Variscan chain and a clastic supply from deeper tectonic units.

关键词： Petrography Stratigraphy Provenance Molassic basins Sardinia

High-speed tracked vehicle model order reduction for static and dynamic simulations

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第8期38卷 89-110页

作者： luca dimauro Simone Venturini Antonio Tota Enrico Galvagno Mauro Velardocchia Department of Mechanical and Aerospace Engineering Politecnico di TorinoCorso Duca degli Abruzzi2410129TorinoItaly

In this paper, a model order reduction strategy is adopted for the static and dynamic behaviour simulation of a high-speed tracked vehicle. The total number of degree of freedom of the structure is condensed through a selection of interface degrees of freedom and significant global mode shapes, for an approximated description of vehicle dynamic behaviour. The methodology is implemented in a customised open-source software to reduce the computational efforts. The modelled tracked vehicle includes the sprung mass, the unsprung masses, connected by means of torsional bars, and all the track assemblies, composing the track chain. The proposed research activity presents a comprehensive investigation of the influence of the track chain, combined with longitudinal vehicle speed, on statics and vehicle dynamics, focusing on vertical dynamics. The vehicle response has been investigated both in frequency and time domain. In this last case road-wheel displacements are assumed as inputs for the model, under different working conditions, hence considering several road profiles with different amplitudes and characteristic excitation frequencies. Simulation results have proven a high fidelity in model order reduction approach and a significant contribution of the track chain in the global dynamic behaviour of the tracked vehicle.

关键词： Tracked vehicle dynamics Rubber characteristics Component mode synthesis Modal analysis Open-source

Application of flame-formed carbon nanoparticle films for ethanol sensing Author links open overlay panel

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第8期91卷 202-210页

作者： Pegah Darvehi luca Basta Mario Commodo Patrizia Minutolo Andrea D'Anna Istituto di Scienze e Tecnologie per l’Energia e la MobilitàSostenibili Consiglio Nazionale delle RicercheP.le Tecchio 8080125NapoliItaly dipartimento di Ingegneria Chimica dei Materiali e della Produzione IndustrialeUniversitàdegli Studi di Napoli Federico IIP.le Tecchio 8080125NapoliItaly

Carbon nanoparticles(CNPs)have received considerable attention due to their exceptional qualities and *** unique physical and chemical characteristics make them extremely intriguing as materials for numerous high-potential applications,such as electronics and gas *** study focused on producing carbon-based nanomaterial devices by deposition of flame-formed carbon nanoparticles on a suitable substrate and investigating their gas-sensing *** were produced in a fuel-rich laminar premixed ethylene/air flame and the collected CNP film was morphologically and electrically *** electrical conductivity of the film was investigated as a function of ethanol concentration and amount of deposited ***,CNP films exhibited high sensitivity to ambient ethanol gas concentrations,and rapid recovery times at room temperature,and showed a sensitivity increasing with the amount of deposited material and the surface *** findings demonstrate the high potential of combustion-generated CNPs as building materials for low-cost and portable ethanol sensors.

关键词： Flame synthesis Carbon nanoparticles Soot Nanostructured thin film Optical and electrical characterization Atomic force microscopy Sensors

Prevention of hepatitis B reactivation in patients with hematologic malignancies treated with novel systemic therapies:Who and Why?

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2024年第5期30卷 509-511页

作者： Matteo Tonnini Clara Solera Horna luca Ielasi Department of Medical and Surgical Sciences University of BolognaBologna 40138Italy division of Internal Medicine Hepatobiliary and Immunoallergic DiseasesIRCCS Azienda Ospedaliero-Universitaria di BolognaBologna 40138Italy Infectious disease Unit Azienda USL-IRCCS di Reggio EmiliaReggio Emilia 42123Italy Department of Internal Medicine Ospedale degli Infermi di FaenzaFaenza 48018Italy

The risk of reactivation in patients with chronic or past/resolved hepatitis B virus(HBV)infection receiving chemotherapy or immunosuppressive drugs is a wellknown *** indication of antiviral prophylaxis with nucleo(t)side analogue is given according to the risk of HBV reactivation of the prescribed *** the advent of new drugs is occurring in all the field of medicine,in the setting of hematologic malignancies the last few years have been characterized by several drug classes and innovative cellular *** novel therapies,there are few data about the rate of HBV reactivation and the decision of starting or not an antiviral prophylaxis could be ***,patients are often treated with a combination of different drugs,so evaluating the actual role of these new therapies in increasing the risk of HBV reactivation is *** results are now available,but further studies are still *** with chronic HBV infection[hepatitis B surface antigen(HBsAg)positive]are reasonably all ***/resolved HBV patients(HBsAg negative)are the actual area of uncertainty where it could be difficult choosing between prophylaxis and pre-emptive strategy.

关键词： Hepatitis B reactivation Hepatitis B virus Antiviral prophylaxis Hematologic malignancies Chimeric antigens receptor-T cell therapy Immune checkpoint inhibitors

Improvement of Surface Mechanical and Tribological Characteristics of L-PBF Processed Commercially Pure Titanium through Ultrasonic Impact Treatment

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2024年第6期37卷 1034-1046页

作者： Iman Ansarian Reza Taghiabadi Saeid Amini Mohammad Hossein Mosallanejad luca Iuliano Abdollah Saboori Department of Materials Science and Metallurgy Imam Khomeini International University(IKIU)QazvinIran Department of Mechanical Engineering University of KashanKashanIran Integrated Additive Manufacturing Center Department of Management and Production EngineeringPolitecnico di TorinoCorso Duca Degli Abruzzi 2410129TurinItaly

Multi-pass ultrasonic impact treatment(UIT)was applied to modify the microstructure and improve the mechanical and tribological characteristics at the near-surface region of commercially pure Ti(CP-Ti)specimens produced by the laser powder bed fusion(L-PBF)*** considerably refined the L-PBF process-related acicular martensites(α′-M)and produced a well-homogenized and dense surface microstructure,where the porosity content of 1-,3-,and 5-pass UITed samples was reduced by 43,60,and 67%,*** UITed samples showed an enhancement in their near-surface mechanical properties up to a depth of about 300μ*** nanoindentation results for the 3-pass UITed sample revealed an increase of about 53,45,and 220%in its nanohardness,H/E_(r),and H_(3)/E_(r)^(2)indices,*** stylus profilometry results showed that performing the UIT removed the L-PBF-related features/defects and offered a smooth *** roughness average(R_(a))and the skewness(R_(sk))of the 3-pass UITed sample were found to be lower than those of the L-PBFed sample by 95 and 223%,*** the UIT also enhanced the material ratio,where the maximum load-bearing capacity(~100%)in as-L-PBFed(as-built)and 3-pass UITed samples was obtained at 60-and 10-µm depths,*** tribological investigations showed that applying the UIT resulted in a significant reduction of wear rate and average coefficient of friction(COF)of *** instance,under the normal pressures of 0.05 and 0.2 MPa,the wear rate and COF of the 3-pass UITed sample were lower than those of the L-PBFed sample by 65 and 58%,and 20 and 17%,respectively.

关键词： Laser powder bed fusion Ultrasonic impact treatment Commercially pure Ti(CP-Ti) Surface mechanical properties Tribological properties