检索结果-南通市图书馆

Correcting distortions of thin-walled machined parts by machine hammer peening

Chinese Journal of Aeronautics 2024年第6期37卷 439-453页

作者： Aitor MADARIAGA Mikel CUESTA Gorka ORTIZ-DE-ZARATE Eneko SAENZ-DE-ARGANDONA Denis SORIANO Michael B.PRIME pedro jose arrazola Department of Materials University of ManchesterOxford RoadManchester M139PLUnited Kingdom Mechanical and Industrial Production Department Faculty of EngineeringMondragon UnibertsitateaArrasate 20500Spain Los Alamos National Laboratory Los AlamosNew MexicoUSA

Thin-walled aerostructural components frequently get distorted after the machining *** to correct distortions or eventually rejecting parts significantly increases the *** paper proposes a new approach to correct distortions in thin-walled components by strategically applying hammer peening on target surfaces of a machined *** alloy 7475-T7351 was chosen for this *** study was divided in two ***,the residual stresses(RS)induced by four different pneumatic hammer peening conditions(modifying the stepover distance and initial offset)were characterised in a test coupon,and one of the conditions was selected for the next *** the second stage,a FEM model was used to predict distortions caused by machining in a representative ***,the RS induced by hammer peening were included in an FEM model to define two hammer peening strategies(varying the coverage area)to analyse the capability to reduce *** workpieces were machined and then treated with the simulated hammer peening strategies for experimental *** in the test coupon showed that pneumatic hammer peening can generate high compressive RS(-50 to350 MPa)up to 800 lm depth,with their magnitude increasing with a reduced stepover *** of hammer peening over 4% of the surface of the representative workpiece reduced the machininginduced distortions by 37%,and a coverage area of 100% led to and overcorrection by a factor of *** confirms that hammer peening can be strategically applied(in target areas and changing the percentage of coverage)to correct low or severe distortions.

关键词： Aeronautics Machining,Hammer Peening Aluminium alloy Distortions Residual Stress

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Improving surface integrity when drilling CFRPs and Ti-6Al-4V using sustainable lubricated liquid carbon dioxide

引用

Chinese Journal of Aeronautics 2023年第7期36卷 129-146页

作者： In˜igo RODRIGUEZ pedro jose´arrazola Mikel CUESTA Luka STERLE Franci PUSˇAVEC Faculty of Engineering Mondragon UnibertsitateaArrasate-Mondragon 20500Spain Faculty of Mechanical Engineering University of LjubljanaLjubljana 1000Slovenia

In the quest for decreasing fuel consumption and resulting gas emissions in the aeronautic sector,lightweight materials such as Carbon Fiber Reinforced Polymers(CFRPs)and Ti-6Al-4V alloys are being *** materials,with excellent weight-to-strength ratios,are widely used for structural applications in aircraft *** date,several studies have been published showing that the use of metalworking fluids(MWFs),special tool geometries,or advanced machining techniques is required to ensure a surface quality that meets aerospace component *** MWFs pose a number of environmental and worker health hazards and also degrade the mechanical properties of CFRPs due to water absorption in the ***,a transition to more environmentally friendly cooling/lubrication techniques that prevent moisture problems in the composite is *** research shows that lubricated LCO_(2) is a viable option to improve the quality of drilled CFRP and titanium aerospace components compared to dry machining,while maintaining clean work *** results show that the best combination of tool geometry and cooling conditions for machining both materials is drilling with Brad point drills and lubricated LCO_(2).Drilling under these conditions resulted in a 90%improvement in fiber pullout volume compared to dry machined CFRP *** addition,a 33% reduction in burr height and a 15% improvement in surface roughness were observed compared to dry drilling of titanium.

关键词： Carbon fibers Cryogenics Green manufacturing Machining Solid lubricants Surface morphology Titanium alloys

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

CONSTANS alters the circadian clock in Arabidopsis thaliana

引用

Molecular Plant 2024年第8期17卷 1204-1220页

作者： pedro de los Reyes Gloria Serrano-Bueno Francisco J.Romero-Campero He Gao jose M.Romero Federico Valverde Plant Development Group-Institute for Plant Biochemistry and Photosynthesis Consejo Superior de Investigaciones CientificasUniversidad de SevillaSevilleSpain Department of Computer Science and Artificial Intelligence Universidad de SevillaSevilleSpain Department of Plant Developmental Biology Max Planck Institute for Plant Breeding ResearchCologneGermany Department of Plant Biochemistry and Molecular Biology Universidad de SevillaSevilleSpain

Plants are sessile organisms that have acquired highly plastic developmental strategies to adapt to the *** these processes,the floral transition is essential to ensure reproductive success and is finelyregulated by several internal andexternal genetic *** photoperiodic pathway,which controls plant response to day length,is one of the most important pathways controlling *** Arabidopsis photoperiodic flowering,CONSTANS(CO)is the central gene activating the expression of the florigen FLOWERING LOCUS T(FT)in the leaves at the end of a long *** circadian clock strongly regulates Co ***,to date,no evidence has been reported regarding a feedbackloop from the photoperiod pathway back to the circadian *** transcriptional networks,we have identified relevant network motifs regulating the interplay between the circadian clock and the photoperiod *** expression,chromatin immunoprecipitation experiments,and phenotypic analysis allowed us to elucidate the role of Co over the circadian *** with altered cO expression showed a different internal clock period,measured by daily leaf rhythmic *** showed that co upregulates the expression of key genes related to the circadian clock,such as CCA1,LHY,PRR5,and Gl,at the end of a long day by bindingto specific sites on their ***,a high numberof PRR5-repressed target genes are upregulated by CO,and this could explain the phase transition promoted by *** CO-PRR5 complex interacts with the bZiP transcriptionfactor HY5andhelps to localize the complex in the promoters of clock *** together,our results indicate that there may be a feedback loop in which co communicates back to the circadian clock,providing seasonal information to the circadian system.

关键词： CONSTANS circadian clock photoperiod

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Employing electrochemically derived pH gradients for Lab-on-PCB protein preconcentration devices

引用

Microsystems & Nanoengineering 2024年第1期10卷 79-87页

作者： Grace Maxted pedro Estrela Despina Moschou Department of Electronic and Electrical Engineering University of BathBath BA27AYUK Centre for Bioengineering and Biomedical Technologies(CBio) University of BathBath BA27AYUK

Protein preconcentration is an essential sample preparation step for analysis in which the targeted proteins exist in low concentrations,such as bodily fluids,water,or ***,very few practical implementations of miniaturized protein preconcentration devices have been demonstrated in practice,and even fewer have been integrated with other microanalytical *** approaches rely heavily on additional chemicals and reagents and introduce complexity to the overall *** this paper,we propose a novel miniaturized isoelectric focusing-based protein preconcentration screening device based on electrochemically derived pH gradients rather than existing chemical reagent *** this way,we reduce the need for additional chemical reagents to zero while enabling device incorporation in a seamlessly integrated full protein analysis microsystem via Lab-on-PCB *** apply our previously presented Lab-on-PCB approach to quantitatively control the pH of a solution in the vicinity of planar electrodes using electrochemical acid generation through redox-active self-assembled *** presented device comprises a printed circuit board with an array of gold electrodes that were functionalized with 4-aminothiophenol;this formed a self-assembled monolayer that was electropolymerized to improve its electrochemical *** preconcentration was performed in two *** first was open and needed the use of a holder to suspend a well of fluid above the electrodes;the second used microfluidic channels to enclose small volumes of *** here are the resulting data for protein preconcentration in both these forms,with a quantitative concentration factor shown for the open form and qualitative proof shown for the microfluidic.

关键词： electrochemical proof qualitative

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Conformational dynamics as an intrinsic determinant of prion protein misfolding and neurotoxicity

引用

Neural Regeneration Research 2024年第10期19卷 2095-2096页

作者： Alessandro Cembran pedro Fernandez-Funez Department of Chemistry and Biochemistry University of Minnesota DuluthDuluthMNUSA Department of Biomedical Sciences University of Minnesota Medical SchoolDuluth CampusDuluthMNUSA

The prion protein(PrP) is the key molecular and pathological mediator of prion diseases,a heterogeneous group of brain disorders with fatal *** diseases are rare but deserve special attention because of their unique f... 详细信息

关键词： folding intrinsic dynamics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of the Coulomb and dielectric forces on the onset of Rayleigh-Bénard convection

引用

Acta Mechanica Sinica 2024年第6期40卷 64-77页

作者： Zhonglin Du pedro A.Vázquez Jian Wu School of Energy Science and Engineering Harbin Institute of TechnologyHarbin150001China Heilongjiang Key Laboratory of Micro-and Nano-scale Fluid Flow and Heat Transfer Harbin150001China Departamento de Física Aplicada III ETSIIUniversidad de SevillaSevilla41092Spain

In this paper,the effect of Coulomb and dielectric forces on the onset of Rayleigh-Bénard convection(RBC)in a dielectric liquid layer contained between two parallel electrode plates has been numerically *** different operating conditions have been considered in electrohydrodynamic(EHD)conduction:ohmic and saturation,and variations in the physical properties of the dielectric fluid with *** electric equations and the state equations based on the Boussinesq approximation are integrated in the framework of OpenFOAM buoyantBoussinesqPimpleFoam *** results show that in the ohmic regime,the combined effect of Coulomb and dielectric forces promotes the onset of RBC flow,while in the saturation state,the inhibition of RBC flow by Coulomb force is more *** value of the critical Rayleigh number Ra decreases with increasing electric Reynolds number ReE in the ohmic regime,whereas in the saturation state,the critical Ra increases with increasing *** the saturation regime,the flow field always has a steady flow in the range of parameters ***,the onset of the RBC flow promoted by the dielectric force is more pronounced in the ohmic *** to the presence of the dielectric force,the flow field exhibits periodic oscillatory flow at low electric Reynolds numbers for the range of parameters considered.

关键词： EHD conduction Dielectric force Rayleigh-Bénard convection OpenFOAM

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Distributed phase-matching measurement for dynamic strain and temperature sensing based on stimulated Brillouin scattering enhanced four-wave mixing

引用

Photonics Research 2024年第1期12卷 141-153页

作者： YUAN WANG pedro TOVAR JUNTONG YANG LIANG CHEN XIAOYI BAO Nexus for Quantum Technologies University of OttawaOttawaOntario K1N 6N5Canada

A Brillouin dynamic grating(BDG) can be used for distributed birefringence measurement in optical fibers,offering high sensitivity and spatial resolution for sensing ***,it is quite a challenge to simultaneously achieve dynamic measurements with both high accuracy and high spatial *** this work,we propose a sensing mechanism to achieve distributed phase-matching measurement using a chirped pulse as a probe *** BDG reflection,the peak reflection corresponds to the highest four-wave mixing(FWM) conversion efficiency,and it requires the Brillouin frequency in the fast and slow axes to be equal,which is called the phase-matching *** condition changes at different fiber positions,which requires a range of frequency injection for the probe *** proposed method uses a chirped pulse as a probe wave to cover this frequency range associated with distributed birefringence *** allows us to detect distributed phase matching for birefringence changes that are introduced by temperature and strain *** to the single shot and direct time delay measurement capability,the acquisition rate in our system is only limited by the fiber ***,unlike conventional BDG spectrum recovery-based systems,the spatial resolution here is determined by both the frequency chirping rate of the probe pulse and the birefringence profile of the *** the experiments,an acquisition rate of 1 k Hz(up to fiber length limits) and a spatial resolution of 10 cm using a 20 ns probe pulse width are *** minimum detectable temperature and strain variation are 5.6 mK and 0.37 με along a 2 km long polarization-maintaining fiber(PMF).

关键词： fiber scattering polarization

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Inversion of walkaway VSP data in the presence of lateral velocity heterogeneity

Energy Geoscience

引用

Energy Geoscience 2024年第2期5卷 304-313页

作者： Vladimir Grechka Ilya Tsvankin pedro Contreras CWP Department of GeophysicsColorado School of MinesGoldenCO80401USA PDVSA-INTEVEP Apartado 76343Caracas1070AVenezuela Borehole Seismic LLC USA Department of Physics ULAVenezuela

Multi-azimuth walkaway vertical seismic profiling is an established technique for the estimation of in situ slowness surfaces and inferring anisotropy ***,this technique requires the assumption of lateral homogeneity,which makes the horizontal slowness components at depths of downhole receivers equal to those measured at the *** violations of this assumption,such as lateral heterogeneity or nonzero dip of intermediate interfaces,lead to distortions in reconstructed slowness surfaces and,consequently,to errors in estimated anisotropic *** this work,we relax the assumption of lateral homogeneity and discuss how to correct vertical seismic profile data for weak lateral *** describe a procedure of downward continuation of recorded traveltimes that accounts for the presence of both vertical inhomogeneity and weak lateral heterogeneity,which produces correct slowness surfaces at depths of downhole receivers,noticing that sufficiently dense receiver coverage along a borehole is required to separate influences of vertical and lateral heterogeneity on measured traveltimes and obtain accurate estimates of the slowness *** the slowness surfaces are found and a desired type of anisotropic model to be inverted is selected,the corresponding anisotropic parameters,providing the best fit to the estimated slownesses,can be *** invert the slowness surfaces of P-waves for parameters of the simplest anisotropic model describing dipping fractures(transversely isotropic medium with a tilted symmetry axis).Five parameters of this model,namely,the P-wave velocity V0 in the direction of the symmetry axis,Thomsen's anisotropic coefficients e and d,the tilt n,and the azimuth b of the symmetry axis,can be estimated in a stable manner when maximum source offset is greater than half of receiver depth.

关键词： Walkaway vertical seismic profile Lateral velocity heterogeneity Anisotropic parameter estimation Vertical inhomogeneity

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

New pharmacological tools:the use of diterpenes to promote adult hippocampal neurogenesis

引用

Neural Regeneration Research 2024年第8期19卷 1629-1630页

作者： Ricardo Gomez-Oliva pedro Nunez-Abades Carmen Castro Department of Biomedicine Biotechnology and Public HealthDivision of PhysiologyUniversity of CadizCadizSpain Biomedical Research and Innovation Institute of Cadiz(INiBICA) CadizSpain Department of Physiology University of SevilleSevilleSpain

Tissue regeneration maintains homeostasis and preserves the functional features of each ***,not all tissues show a strong repairing *** is the case of the central nervous *** is now well established that the generation of new functional neurons from stem cells in the adult brain occurs in specific regions of the brain of different species such as rodents,birds,primates,and humans(Eriksson et al.,1998).

关键词： capacity maintain preserve

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Targeting epidermal growth factor receptor signaling to facilitate cortical injury repair?

引用

Neural Regeneration Research 2024年第5期19卷 935-936页

作者： Ricardo Gómez-Oliva pedro Nunez-Abades Carmen Castro Área de Fisiología Facultad de Medicina Universidad de CádizCadizSpain Instituto de Investigación e Innovación en Biomedicina de Cádiz CadizSpain Departamento de Fisiología Facultad de FarmaciaUniversidad de SevillaSevilleSpain

The existence of neural stem cells(NSC)in specific areas of the adult mammalian brain leads to the generation of new neurons involved in homeostatic *** is the case of the NSC of the subventricular zone(SVZ)that produces olfactory bulb(OB)*** neurons integrate into circuits to modulate sensory information and participate in olfactory processing(Bragado Alonso et al.,2019).A series of hierarchical events need to take place to produce OB neurons from NSC of the ***,the activation of quiescent NSC is necessary to produce intermediate transit amplifying progenitors(TAP),which will generate *** latter are cells that maintain a proliferative phenotype while in an immature ***,once they initiate migration toward the OB,they progressively undergo their differentiation into neurons(Kjell et al.,2020).

关键词： ventricular maintain

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：