Modeling the boundary layer flow of ternary hybrid nanofluids is important for understanding and optimizing their thermal performance,particularly in applications where enhanced heat transfer and fluid dynamics are es...Modeling the boundary layer flow of ternary hybrid nanofluids is important for understanding and optimizing their thermal performance,particularly in applications where enhanced heat transfer and fluid dynamics are essential.This study numerically investigates the boundary layer flow of alumina-copper-silver/water nanofluid over a permeable stretching/shrinking sheet,incorporating both first and second-order velocity slip.The mathematical model is solved in MATLAB facilitated by the bvp4c function that employs the finite difference scheme and Lobatto IIIa formula.The solver successfully generates dual solutions for the model,and further analysis is conducted to assess their stability.The findings reported that only one of the solutions is stable.For the shrinking sheet case,increasing the first-order velocity slip delays boundary layer separation and enhances heat transfer,while,when the sheet is stretched,the second-order velocity slip accelerates separation and improves heat transfer.Boundary layer separation is most likely to occur when the sheet is shrinking;however,this can be controlled by adjusting the velocity slip with the inclusion of boundary layer suction.展开更多
Spontaneous speech errors(slips of the tongue),although infrequent,reveal what we really think in our mind.And slips of the mind also help us reveal planning units in the production of speech as well as to know a lot ...Spontaneous speech errors(slips of the tongue),although infrequent,reveal what we really think in our mind.And slips of the mind also help us reveal planning units in the production of speech as well as to know a lot about our mental dictionary and second language production as well.This essay will take a deep insight into this language phenomenon.展开更多
Slip is one of the most critical components for the frac plug,which would lodge into the casing and lock the frac plug in place during the setting and anchoring process.However,fracture failure of slip significantly a...Slip is one of the most critical components for the frac plug,which would lodge into the casing and lock the frac plug in place during the setting and anchoring process.However,fracture failure of slip significantly affects the hydraulic fracturing effects and has attracted tremendous attention.In this paper,a three-dimensional contact model is applied to explore the setting process of slip.The effects of key structural parameters such as apex angle,inclination angle,and wedge angle on the contact characteristics of slip are systematically investigated.Numerical results indicate that the maximum contact stress appears at the contact area between slip tooth and the casing’s inner wall.Besides,the maximum contact stress generally increases with the increase of apex angle and inclination angle,while decrease linearly with the rise in the wedge angle.Experimental results show that the slip teeth get blunt and appear severe plastic deformation,which arises from stress concentration.Comparison of biting area indicates that the experimental results are about 21.3%larger,which still have a reasonable agreement with the numerical results.These obtained results can guide the parametric selection of plug slip and other similar components.展开更多
An algorithm has been developed from various exiting techniques,that provides fully automatic cycle-slip detection at the data preprocessing stage.This algorithm,called pair linear combination,operates on undifference...An algorithm has been developed from various exiting techniques,that provides fully automatic cycle-slip detection at the data preprocessing stage.This algorithm,called pair linear combination,operates on undifferenced or double-differenced,dual frequency carrier phase data,and requires the sampling interval is short.Test results carried out in a variety of situations including static and kinematic modes,short and long baseline situation,and low and high data rates were presented.展开更多
Among the bamboo slips dating to the Warring States period(475-221 BCE),stored at Tsinghua University,there is an aggregate of 21 specially shaped slips that are painted with red lines on the obverse side.Numbers are ...Among the bamboo slips dating to the Warring States period(475-221 BCE),stored at Tsinghua University,there is an aggregate of 21 specially shaped slips that are painted with red lines on the obverse side.Numbers are written on 20 slips in accordance with certain rules,and on one slip without numbers there are 20 round holes and residues of ribbon.These slips,after being compiled as a whole,serve as a practical calculator in the form of a table,which is designated as Suan Biao算表(the multiplication table).In this paper,the structure and functions of the Suan Biao are discussed by comparing it with other ancient multiplication tables.Specifically,it is noted that the core of the Suan Biao is a multiplication table comprising the numbers 9 to 1 and their products 81 to 1;the other parts are an extension of the core.The Suan Biao employs the decimal place value system and manifested the author’s knowledge of the commutative law of multiplication,the distributive law of multiplication over addition,and fractions.Not only is this table directly applicable to the multiplication of two-digit numbers,but also to division.In addition,certain computations regarding 1/2 or fractions containing 1/2 can be conducted using this table,and it may also be used for extracting roots.The Suan Biao is of great significance for research on ancient mathematics,and its discovery is enormously valuable for studies on arithmetic methods and computational tools in early China.展开更多
Mountain tunnel crossing a normal fault in seismically active zone is easily affected by normal fault slip and earthquake. It is necessary to study tunnel dynamic response under action of normal fault slip and earthqu...Mountain tunnel crossing a normal fault in seismically active zone is easily affected by normal fault slip and earthquake. It is necessary to study tunnel dynamic response under action of normal fault slip and earthquake. In this paper, a three-dimensional normal fault sliding device was designed, and a shaking table test was carried out to study tunnel seismic performance under normal fault slip. The results show that peak acceleration of lining is dominated by an existence of fault and direction of seismic excitation, not normal fault slip. And the incremental strains of lining in critical zone with 1.7 times fault thickness and centered in faults induced by normal fault slip and seismic excitation are larger than ones only by seismic excitation. And the incremental strains in critical zone increase with the increase of normal fault slip magnitude ranging from 0 to 2 mm. And normal fault slip results in a significant reduction of overall tunnel stiffness subjected to an earthquake. These experimental results provide a scientific reference for prevention and control measurement of tunnel damage under earthquake and normal fault slip.展开更多
In March 2021,a seismic sequence including three Mw>5.5 events struck northern Thessaly,Greece.Owing to the high temporal resolution of Sentinel-1 images which were sampled every 6 days and recorded the three event...In March 2021,a seismic sequence including three Mw>5.5 events struck northern Thessaly,Greece.Owing to the high temporal resolution of Sentinel-1 images which were sampled every 6 days and recorded the three events separately,we are able to map individually the coseismic deformation fields of the three events.Based on their respective coseismic displacements,we determined the geometry of the fault plane for each earthquake with the method of multipeak particle swarm optimization and inverted the best-fitting slip distribution by linear least squares inversion.Modelling results show that the three events occurred successively on 3,4 and 12 March 2021 were all dominated by normal-slip motions on previously unknown faults within the top 15 km of the Earth’s crust.The 3 March 2021 Mw 6.3 earthquake ruptured a northeast-dipping fault with a strike angle of 301°(clockwise from the North)and a dip angle of 46°,producing the maximum slip of about 2.2 m.The slip motion of the 4 March 2021 Mw 5.9 aftershock shows a similar fault geometry(striking 297°and dipping 42°)to the 3 March mainshock,but with a considerably smaller dip-slip component(~0.8 m).The 12 March 2021 Mw 5.6 aftershock occurred on a southwest-dipping fault(striking 100°and dipping 40°)with a normal fault slip of up to 0.5 m.Static Coulomb stress changes triggered by the earthquake sequence imply a promotion relationship between the first 3 March event and the two subsequent events.Due to the coseismic stress perturbation,more than 70%of aftershocks were distributed in areas with increased Coulomb stress and the northwest segment of the Larissa fault close to the seismic sequence was exposed to a relatively high seismic risk.展开更多
For the development of alert systems for soil slip occurrence, it is important to evaluate the degree of saturation of shallow soils (Sr) over wide areas. Taking into account the possibility to estimate spatial and te...For the development of alert systems for soil slip occurrence, it is important to evaluate the degree of saturation of shallow soils (Sr) over wide areas. Taking into account the possibility to estimate spatial and temporal variation of soil moisture using remote sensing techniques, a possible correlation between Sr and the daily output of a sequential data assimilation system called ACHAB (Assimilation Code for HeAt and moisture Balance) has been studied. ACHAB is based on integrated use of remotely sensed land surface temperature (LST) and common data on meteorological forcing such as air temperature, wind-speed and incident solar radiation. The aim of this study is to understand if it is possible to use ACHAB output (a daily value of evaporative fraction for the whole Italian territory) to define the parameter Sr that could be introduced in a simplified model for the description of soil slip triggering mechanisms on territorial scale.展开更多
Ever since the publication of Fromkin＇s Slips of the Tongue in 1973, more and more psycholinguists have realized the importance of studying the slips of the tongue. Dell （1986） defined slips of the tongue as ＂unin...Ever since the publication of Fromkin＇s Slips of the Tongue in 1973, more and more psycholinguists have realized the importance of studying the slips of the tongue. Dell （1986） defined slips of the tongue as ＂unintended, nonhabitual deviation（s） from a speech plan＂. That is, those speech errors are not due to an incomplete or incorrect language system, but to language processing problems. Most of the studies are focused on monohngual models. But, to bilinguals, are L2 slips different from LI slips？ Can those monolingual speech production models also explain L2 speech production？ This article puts together Dell＇s current monolingual model of speech with Poulisse＇s L2 slip project to see how L2 slips can shed light on the process of L2 speech production and L2 learning orocess.展开更多
This study investigates the plastic deformation behaviour of the AZ31 magnesium alloy under various uniaxial loading conditions using in-situ neutron diffraction,the crystallite group method(CGM),and crystal plasticit...This study investigates the plastic deformation behaviour of the AZ31 magnesium alloy under various uniaxial loading conditions using in-situ neutron diffraction,the crystallite group method(CGM),and crystal plasticity modelling.A key novelty of this work is the direct,model independent determination of resolved shear stress(RSS)values for individual slip and twinning systems,as well as their critical values(CRSS),derived from lattice strains in grains with preferred orientations.The experiment was extended beyond the conventional loading paths along the normal direction(ND)and rolling direction(RD)to include compression at angles of 30°and 60°from the ND(referred to as NDC30 and NDC60 tests),which had not been investigated in previous studies.Notably,the NDC30 test,combined with diffraction measurements,was specifically designed to activate basal slip in the majority of grains while minimizing twinning,enabling clear identification of this slip system and accurate determination of its CRSS.For the first time,hardening parameters were determined by comparing the model predicted values of RSS with those obtained from diffraction measurements for each active system.These data,together with the results of macroscopic tests,were used to calibrate an elastic-plastic self-consistent(EPSC)model,which accurately reproduced stress partitioning under applied load,texture evolution,and twin activity.The integrated methodology enhances the reliability of CRSS input and improves the modelling of anisotropic plasticity in magnesium alloys by tuning intergranular interactions based on a modified Eshelby inclusion approach.展开更多
We examine Qin Dynasty(221 to 207 BCE)wood bookkeeping slips from 217 to 210 BCE unearthed in Hunan province,China.While purely written slips were unearthed before,these slips are unique in that they contain written r...We examine Qin Dynasty(221 to 207 BCE)wood bookkeeping slips from 217 to 210 BCE unearthed in Hunan province,China.While purely written slips were unearthed before,these slips are unique in that they contain written records of details oftransactions as well as notches on their sides that represent the quantities of money or measures of commodities involved.Scholars have speculated that ancient engraving,notching or tokening before the development of written language could be bookkeeping/accounting.We show a form of bookkeeping combining notching with written records that emerged at a point in Chinese history where a region saw a temporary dip in local literacy.Notching reappeared to compensate for the loss in literacy to prevent fraud and reduce bookkeepers’risk of being accused of fraud.This for of dualmethod bookkeeping adds credence to the conjecture that prehistorical,prelanguage notching,engraving or tokening was likely bookkee ping/accounting.展开更多
With the advancement of surface technology, boundary slip in lubrication has become increasingly common. However, theoretical analysis in this area remains limited, necessitating further research to explore the impact...With the advancement of surface technology, boundary slip in lubrication has become increasingly common. However, theoretical analysis in this area remains limited, necessitating further research to explore the impact of boundary slip, particularly thermal slip induced by velocity slip in cases with obvious thermal rise. Additionally, investigating the influence of surface limiting shearing stress on boundary slip is a valuable area of study. This research extends the simple sliding finite line contact thermal elastohydrodynamic lubrication (EHL) model by incorporating velocity slip and thermal slip at boundaries. Firstly, linear slip is examined in three different conditions, and the impact of boundary slip on the lubrication state is analyzed. Building upon this, the study considers the effect of limiting shearing stress on boundary slip and develops a nonlinear slip model. The study conducts a thorough analysis of the influence of limiting shearing stress on the lubrication state in the contact area and reveals that friction reduction can be attained by introducing slip between the static surface and the lubricant. By investigating the impact of boundary slip and limiting shearing stress on thermal EHL under simple sliding conditions, this research puts forward a novel friction reduction approach based on the theory of boundary slip.展开更多
The deformation behavior of GH4169 superalloy under room-temperature uniaxial tension was investigated through synchronized mesoscopic digital image correlation(DIC)and electron backscatter diffraction(EBSD)in-situ ch...The deformation behavior of GH4169 superalloy under room-temperature uniaxial tension was investigated through synchronized mesoscopic digital image correlation(DIC)and electron backscatter diffraction(EBSD)in-situ characterization techniques.Results show that in the field of grain deflection dynamics,through quantitative analysis using the independently developed M-DIC software,during uniaxial tension with significant bidirectional rotation along the tensile axis and the stress level of 1100 MPa,oscillatory rotation of±0.6°can be obtained,and microvoids are generated at the grain boundaries with 45°to the stress axis.EBSD crystallographic analysis demonstrates the load-dependent slip system evolution:in the initial stage,the soft-oriented systems with high Schmid factor(>0.4)is activated and then transformed into hard-oriented systems during cross-slip,generating parallel slip bands and dislocation pile-ups at grain boundaries.During the uniaxial tensile process,the characteristic of strain energy accumulation is observed,which follows a two-stage accumulation pattern:initial grain boundary localization(Stage I)and intragranular propagation(Stage II).Ultimately,the intergranular cracks are initiated at triple junctions,and the twin boundaries exhibit superior mechanical stability compared with the large-angle grain boundaries.Deformation texture characteristics indicate the copper-type components,including C{112}<111¯>,S{123}<634¯>,and B{110}<11¯0>.The complete deformation sequence is as follows:cross-slip of soft-oriented slip systems→initiation of dislocation slip→strain partitioning through grain rotation→intergranular stress concentration→damage dominated by boundary cracking.The cross-scale deformation mechanism revealed in this study provides critical guidance for the crystal boundary engineering to optimize nickel-based superalloys.展开更多
Ultrafine-grained(UFG)pure titanium was produced by equal channel angular pressing for 4 passes,followed by rotatory swaging at room temperature.The strain-controlled low-cycle fatigue tests of UFG and coarse-grained(...Ultrafine-grained(UFG)pure titanium was produced by equal channel angular pressing for 4 passes,followed by rotatory swaging at room temperature.The strain-controlled low-cycle fatigue tests of UFG and coarse-grained(CG)pure titanium were conducted by Instron electro-hydraulic servo fatigue testing machine in the strain amplitude range of 0.5%—1.1%at room temperature.Transmission electron microscope(TEM)and scanning electron microscope were used to investigate the microstructure and fracture surface of UFG pure titanium after fatigue tests.Results show that UFG pure titanium exhibits a longer low-cycle fatigue life,compared with the CG pure titanium.For example,at a total strain amplitude of 0.5%,UFG and CG pure titanium has fatigue life of 10850 and 4820 cycles,respectively.Significant cyclic softening occurs in UFG pure titanium,except in the case of a total strain amplitude of 0.5%.Hysteresis loop area is increased rapidly with the increase in strain amplitude.The fracture surface shows that the fatigue crack is initiated from the specimen surface.A series of fatigue striations and many microcracks exist in the propagation region.With the increase in strain amplitude,the predominant failure mode is transformed from ductile failure into quasi-cleavage failure.Dislocation slip is the main plastic deformation mechanism of UFG pure titanium during low-cycle fatigue deformation.展开更多
This essay agrees that the two controversial characters on Slip 12 of the Hengxian 亘先 should be transcribed as ＂ ~ and ＂ ＂ and pronounced as ＂ji＂ 极. Secondly, with respect to six occurrences of the charact...This essay agrees that the two controversial characters on Slip 12 of the Hengxian 亘先 should be transcribed as ＂ ~ and ＂ ＂ and pronounced as ＂ji＂ 极. Secondly, with respect to six occurrences of the character ＂亘＂ （heng） on Slips 1-9 which Qiu Xigui 裘锡圭 reads as ＂极＂ （ji）, this essay holds that in the end it should be read as ＂恒＂ （heng）, and that the reading provided by Li Ling is acceptable. Therefore, that piece of bamboo slip writing can be named ＂恒先＂ （Hengxian）. Thirdly, ＂亘＂ （heng） and ＂亘先＂ （hengxian）, or ＂恒＂ （heng） and ＂恒先＂ （hengxian）, are two concepts, the latter of which is based on the former. ＂亘＂ （heng） is more fundamental and more important than ＂亘先＂ （hengxian）. Scholars mostly equate ＂恒＂ （heng） with ＂恒先＂ （hengxian）, and even regard ＂恒先＂ as the prior expression of this concept. One can hardly say that this is correct. In the bamboo writing, ＂恒＂ （heng） actually refers to ＂tian dao＂ 天道（heavenly dao）, rather than ＂dao＂ in the Laozi. The so-called ＂恒先＂ （hengxian） suggests the very commencement of the genesis and evolvement of Heavenly dao, which is somewhat equivalent to ＂taishi＂ 太始 （grand commencement） in the Huainanzi 淮南子. Fourthly, in the Hengxian, ＂恒＂ （heng） implies objective and natural laws, while ＂极＂ （ji） suggests ought-to-be rules. ＂极＂ （ji） in the bamboo writing is actually informed by ＂恒＂ （heng）.展开更多
Yogyakarta was struck by a devastating Mw6.3 earthquake,which intensified awareness about the seismic hazards in the region.This study investigates the kinematic slip rate and seismogenic depth of the northern segment...Yogyakarta was struck by a devastating Mw6.3 earthquake,which intensified awareness about the seismic hazards in the region.This study investigates the kinematic slip rate and seismogenic depth of the northern segment of Opak Fault and an unmapped fault known as Ngalang Fault in Yogyakarta,utilizing Global Navigation Satellite System(GNSS)data collected between 2019 and 2023.By deploying a network of 12 GNSS stations alongside continuous observations from the InaCORS network,we perfo rmed a detailed geodetic analysis to discern current defo rmation patterns.To quantify the slip rate,we established a frame of reference using the Sundaland Block's rotational parameters and applied the Euler pole angular velocity to transform daily GNSS solutions acco rdingly.The findings reveal significant left-lateral strike-slip motion in the northern segment of Opak Fault,with a slip rate averaging 3 mm/yr and a locking depth of 2.1 km in Northern Segment,whereas the slip rate averages 1.1 mm/yr and the locking depth is estimated at 1 km in the Ngalang Fault,indicating active geological movements that may influence future seismicity.展开更多
The interrupted fatigue test method was utilized to investigate the damage evolution mechanism of the notch high-cycle fatigue(NHCF)in Ti-55531 alloy with a multilevel lamellar microstructure.The results reveal that s...The interrupted fatigue test method was utilized to investigate the damage evolution mechanism of the notch high-cycle fatigue(NHCF)in Ti-55531 alloy with a multilevel lamellar microstructure.The results reveal that significant microvoids and microcracks predominantly initiate at α/β interfaces under various notch root radii(R).Notably,even under larger R(0.75 mm),mutual interactions of stacking faults(SFs)−deformation twins,twins−twins,and SFs−SFs are observed.Furthermore,with decreasing R(0.34 and 0.14 mm),the volume fraction of SFs escalates significantly and twins are almost absent.Moreover,activated prismatic slip system decreases with a decrease in Schmidt factor and with the further decrease in R.Finally,strain localization near α/β interfaces contributes to the initiation of fatigue microcracks.展开更多
The shallow slip deficit(SSD)during strike-slip earthquakes raises a question of how the strain budget is accommodated over multiple cycles.However,the origin of variable SSD observed in different earthquakes is still...The shallow slip deficit(SSD)during strike-slip earthquakes raises a question of how the strain budget is accommodated over multiple cycles.However,the origin of variable SSD observed in different earthquakes is still under debate because each earthquake has its unique initial stress condition.Here,we derive the slip model of the 2021 M_(W) 7.4 Maduo earthquake in Qinghai,China,using multi-track radar images.Our results revealed that,in contrast to the large SSD on segments close to the epicenter,a much smaller SSD was observed at the west terminus of the rupture,where aftershock distribution indicates that the fault changes dip direction at 6 km depth.The 2021 Maduo earthquake thus represents an extraordinary case of significant along-strike SSD variation.After accounting for interseismic,postseismic,and diffuse off-fault deformation,we find that this variation is likely contributed by the along-dipping geometrical variation,implying that a multi-segment earthquake may leave heterogeneous stress condition on the fault with different amounts of SSD.展开更多
基金The authors acknowledged Universiti Putra Malaysia for the Putra Grant that was received(GP-IPM 9787700)supported by Grant PN-III-P4-PCE-2021-0993,UEFISCDI,Romania.
文摘Modeling the boundary layer flow of ternary hybrid nanofluids is important for understanding and optimizing their thermal performance,particularly in applications where enhanced heat transfer and fluid dynamics are essential.This study numerically investigates the boundary layer flow of alumina-copper-silver/water nanofluid over a permeable stretching/shrinking sheet,incorporating both first and second-order velocity slip.The mathematical model is solved in MATLAB facilitated by the bvp4c function that employs the finite difference scheme and Lobatto IIIa formula.The solver successfully generates dual solutions for the model,and further analysis is conducted to assess their stability.The findings reported that only one of the solutions is stable.For the shrinking sheet case,increasing the first-order velocity slip delays boundary layer separation and enhances heat transfer,while,when the sheet is stretched,the second-order velocity slip accelerates separation and improves heat transfer.Boundary layer separation is most likely to occur when the sheet is shrinking;however,this can be controlled by adjusting the velocity slip with the inclusion of boundary layer suction.
文摘Spontaneous speech errors(slips of the tongue),although infrequent,reveal what we really think in our mind.And slips of the mind also help us reveal planning units in the production of speech as well as to know a lot about our mental dictionary and second language production as well.This essay will take a deep insight into this language phenomenon.
基金financial support from the National Major Science and Technology Projects of China(Grant No.2017ZX05072)the Royal Society Newton International Fellowships(Grant No.NIF/R1/181640)the Marie SkłodowskaCurie Individual Fellowships under European Union’s Horizon 2020 research and innovation programme(Grant No.840264)
文摘Slip is one of the most critical components for the frac plug,which would lodge into the casing and lock the frac plug in place during the setting and anchoring process.However,fracture failure of slip significantly affects the hydraulic fracturing effects and has attracted tremendous attention.In this paper,a three-dimensional contact model is applied to explore the setting process of slip.The effects of key structural parameters such as apex angle,inclination angle,and wedge angle on the contact characteristics of slip are systematically investigated.Numerical results indicate that the maximum contact stress appears at the contact area between slip tooth and the casing’s inner wall.Besides,the maximum contact stress generally increases with the increase of apex angle and inclination angle,while decrease linearly with the rise in the wedge angle.Experimental results show that the slip teeth get blunt and appear severe plastic deformation,which arises from stress concentration.Comparison of biting area indicates that the experimental results are about 21.3%larger,which still have a reasonable agreement with the numerical results.These obtained results can guide the parametric selection of plug slip and other similar components.
基金Project(40174005)supported by the National Natural Science Foundation of China
文摘An algorithm has been developed from various exiting techniques,that provides fully automatic cycle-slip detection at the data preprocessing stage.This algorithm,called pair linear combination,operates on undifferenced or double-differenced,dual frequency carrier phase data,and requires the sampling interval is short.Test results carried out in a variety of situations including static and kinematic modes,short and long baseline situation,and low and high data rates were presented.
文摘Among the bamboo slips dating to the Warring States period(475-221 BCE),stored at Tsinghua University,there is an aggregate of 21 specially shaped slips that are painted with red lines on the obverse side.Numbers are written on 20 slips in accordance with certain rules,and on one slip without numbers there are 20 round holes and residues of ribbon.These slips,after being compiled as a whole,serve as a practical calculator in the form of a table,which is designated as Suan Biao算表(the multiplication table).In this paper,the structure and functions of the Suan Biao are discussed by comparing it with other ancient multiplication tables.Specifically,it is noted that the core of the Suan Biao is a multiplication table comprising the numbers 9 to 1 and their products 81 to 1;the other parts are an extension of the core.The Suan Biao employs the decimal place value system and manifested the author’s knowledge of the commutative law of multiplication,the distributive law of multiplication over addition,and fractions.Not only is this table directly applicable to the multiplication of two-digit numbers,but also to division.In addition,certain computations regarding 1/2 or fractions containing 1/2 can be conducted using this table,and it may also be used for extracting roots.The Suan Biao is of great significance for research on ancient mathematics,and its discovery is enormously valuable for studies on arithmetic methods and computational tools in early China.
基金Project(51674287)supported by the National Natural Science Foundation of China。
文摘Mountain tunnel crossing a normal fault in seismically active zone is easily affected by normal fault slip and earthquake. It is necessary to study tunnel dynamic response under action of normal fault slip and earthquake. In this paper, a three-dimensional normal fault sliding device was designed, and a shaking table test was carried out to study tunnel seismic performance under normal fault slip. The results show that peak acceleration of lining is dominated by an existence of fault and direction of seismic excitation, not normal fault slip. And the incremental strains of lining in critical zone with 1.7 times fault thickness and centered in faults induced by normal fault slip and seismic excitation are larger than ones only by seismic excitation. And the incremental strains in critical zone increase with the increase of normal fault slip magnitude ranging from 0 to 2 mm. And normal fault slip results in a significant reduction of overall tunnel stiffness subjected to an earthquake. These experimental results provide a scientific reference for prevention and control measurement of tunnel damage under earthquake and normal fault slip.
基金National Key Research and Development Program of China(No.2019YFC1509201)Chinese Scholarship Council Studentship(No.201806270247)+3 种基金Shaanxi Province Science and Technology Innovation Team(No.2021TD-51)UK Natural Environment Research Council through the Centre for the Observation and Modeling of Earthquakes,Volcanoes and Tectonics(No.come30001)LICS Project(No.NE/K010794/1)European Space Agency through the ESA-MOST DRAGON-5 Project(No.59339)。
文摘In March 2021,a seismic sequence including three Mw>5.5 events struck northern Thessaly,Greece.Owing to the high temporal resolution of Sentinel-1 images which were sampled every 6 days and recorded the three events separately,we are able to map individually the coseismic deformation fields of the three events.Based on their respective coseismic displacements,we determined the geometry of the fault plane for each earthquake with the method of multipeak particle swarm optimization and inverted the best-fitting slip distribution by linear least squares inversion.Modelling results show that the three events occurred successively on 3,4 and 12 March 2021 were all dominated by normal-slip motions on previously unknown faults within the top 15 km of the Earth’s crust.The 3 March 2021 Mw 6.3 earthquake ruptured a northeast-dipping fault with a strike angle of 301°(clockwise from the North)and a dip angle of 46°,producing the maximum slip of about 2.2 m.The slip motion of the 4 March 2021 Mw 5.9 aftershock shows a similar fault geometry(striking 297°and dipping 42°)to the 3 March mainshock,but with a considerably smaller dip-slip component(~0.8 m).The 12 March 2021 Mw 5.6 aftershock occurred on a southwest-dipping fault(striking 100°and dipping 40°)with a normal fault slip of up to 0.5 m.Static Coulomb stress changes triggered by the earthquake sequence imply a promotion relationship between the first 3 March event and the two subsequent events.Due to the coseismic stress perturbation,more than 70%of aftershocks were distributed in areas with increased Coulomb stress and the northwest segment of the Larissa fault close to the seismic sequence was exposed to a relatively high seismic risk.
文摘For the development of alert systems for soil slip occurrence, it is important to evaluate the degree of saturation of shallow soils (Sr) over wide areas. Taking into account the possibility to estimate spatial and temporal variation of soil moisture using remote sensing techniques, a possible correlation between Sr and the daily output of a sequential data assimilation system called ACHAB (Assimilation Code for HeAt and moisture Balance) has been studied. ACHAB is based on integrated use of remotely sensed land surface temperature (LST) and common data on meteorological forcing such as air temperature, wind-speed and incident solar radiation. The aim of this study is to understand if it is possible to use ACHAB output (a daily value of evaporative fraction for the whole Italian territory) to define the parameter Sr that could be introduced in a simplified model for the description of soil slip triggering mechanisms on territorial scale.
文摘Ever since the publication of Fromkin＇s Slips of the Tongue in 1973, more and more psycholinguists have realized the importance of studying the slips of the tongue. Dell （1986） defined slips of the tongue as ＂unintended, nonhabitual deviation（s） from a speech plan＂. That is, those speech errors are not due to an incomplete or incorrect language system, but to language processing problems. Most of the studies are focused on monohngual models. But, to bilinguals, are L2 slips different from LI slips？ Can those monolingual speech production models also explain L2 speech production？ This article puts together Dell＇s current monolingual model of speech with Poulisse＇s L2 slip project to see how L2 slips can shed light on the process of L2 speech production and L2 learning orocess.
基金founded by the National Science Centre,Poland(NCN),under grant no.UMO-2023/49/B/ST11/00774The research(neutron diffraction experiments)leading to this result has been co-funded by the project NEPHEWS under grant agreement no.101131414 from the EU Framework Programme for Research and Innovation Horizon Europe+6 种基金Views and opinions expressed are however those of the author(s)only and do not necessarily reflect those of the European Union.Neither the European Union nor the granting authorities can be held responsible for them.Measurements were carried out at the CANAM infrastructure of the NPI CAS Rez.The employment of the CICRR infrastructure supported by MEYS project LM2023041 is acknowledgedThe Ministry of Education,Youth and Sports of the Czech Republic(MEYS),support of large research infrastructures LM2023057K.M.acknowledges support of the Czech Grant Agency under project no.25-16210SP.K.acknowledges support from the European Union's Horizon 2020 research and innovation program under the NOMATEN teaming grant agreement no.857470the European Regional Development Fund via the Foundation for Polish Science International Research Agenda Plus Program grant no.MAB PLUS/2018/8the Ministry of Science and Higher Education's initiative“Support for the Activities of Centers of Excellence Established in Poland under the Horizon 2020 Program”under agreement no.MEiN/2023/DIR/3795K.W.was partly supported by the program“Excellence initiative-research university”for the AGH University of Krakow.
文摘This study investigates the plastic deformation behaviour of the AZ31 magnesium alloy under various uniaxial loading conditions using in-situ neutron diffraction,the crystallite group method(CGM),and crystal plasticity modelling.A key novelty of this work is the direct,model independent determination of resolved shear stress(RSS)values for individual slip and twinning systems,as well as their critical values(CRSS),derived from lattice strains in grains with preferred orientations.The experiment was extended beyond the conventional loading paths along the normal direction(ND)and rolling direction(RD)to include compression at angles of 30°and 60°from the ND(referred to as NDC30 and NDC60 tests),which had not been investigated in previous studies.Notably,the NDC30 test,combined with diffraction measurements,was specifically designed to activate basal slip in the majority of grains while minimizing twinning,enabling clear identification of this slip system and accurate determination of its CRSS.For the first time,hardening parameters were determined by comparing the model predicted values of RSS with those obtained from diffraction measurements for each active system.These data,together with the results of macroscopic tests,were used to calibrate an elastic-plastic self-consistent(EPSC)model,which accurately reproduced stress partitioning under applied load,texture evolution,and twin activity.The integrated methodology enhances the reliability of CRSS input and improves the modelling of anisotropic plasticity in magnesium alloys by tuning intergranular interactions based on a modified Eshelby inclusion approach.
基金the National Social Science Foundation of China:“Research on Historical Materials of Accounting Books in Unearthed Bamboo and Wooden Slips”(Project Approval No.:22FJYB056).
文摘We examine Qin Dynasty(221 to 207 BCE)wood bookkeeping slips from 217 to 210 BCE unearthed in Hunan province,China.While purely written slips were unearthed before,these slips are unique in that they contain written records of details oftransactions as well as notches on their sides that represent the quantities of money or measures of commodities involved.Scholars have speculated that ancient engraving,notching or tokening before the development of written language could be bookkeeping/accounting.We show a form of bookkeeping combining notching with written records that emerged at a point in Chinese history where a region saw a temporary dip in local literacy.Notching reappeared to compensate for the loss in literacy to prevent fraud and reduce bookkeepers’risk of being accused of fraud.This for of dualmethod bookkeeping adds credence to the conjecture that prehistorical,prelanguage notching,engraving or tokening was likely bookkee ping/accounting.
基金supported by the National Natural Science Foundation of China(No.51875298)Shandong Provincial Natural Science Foundation(No.ZR2019MEE040)the Fundamental Research Funds for the Central Universities and Graduate Student Innovation Fund of Donghua University(No.CUSF-DH-D-2023033).
文摘With the advancement of surface technology, boundary slip in lubrication has become increasingly common. However, theoretical analysis in this area remains limited, necessitating further research to explore the impact of boundary slip, particularly thermal slip induced by velocity slip in cases with obvious thermal rise. Additionally, investigating the influence of surface limiting shearing stress on boundary slip is a valuable area of study. This research extends the simple sliding finite line contact thermal elastohydrodynamic lubrication (EHL) model by incorporating velocity slip and thermal slip at boundaries. Firstly, linear slip is examined in three different conditions, and the impact of boundary slip on the lubrication state is analyzed. Building upon this, the study considers the effect of limiting shearing stress on boundary slip and develops a nonlinear slip model. The study conducts a thorough analysis of the influence of limiting shearing stress on the lubrication state in the contact area and reveals that friction reduction can be attained by introducing slip between the static surface and the lubricant. By investigating the impact of boundary slip and limiting shearing stress on thermal EHL under simple sliding conditions, this research puts forward a novel friction reduction approach based on the theory of boundary slip.
基金National Natural Science Foundation of China(2022YFF0609300)。
文摘The deformation behavior of GH4169 superalloy under room-temperature uniaxial tension was investigated through synchronized mesoscopic digital image correlation(DIC)and electron backscatter diffraction(EBSD)in-situ characterization techniques.Results show that in the field of grain deflection dynamics,through quantitative analysis using the independently developed M-DIC software,during uniaxial tension with significant bidirectional rotation along the tensile axis and the stress level of 1100 MPa,oscillatory rotation of±0.6°can be obtained,and microvoids are generated at the grain boundaries with 45°to the stress axis.EBSD crystallographic analysis demonstrates the load-dependent slip system evolution:in the initial stage,the soft-oriented systems with high Schmid factor(>0.4)is activated and then transformed into hard-oriented systems during cross-slip,generating parallel slip bands and dislocation pile-ups at grain boundaries.During the uniaxial tensile process,the characteristic of strain energy accumulation is observed,which follows a two-stage accumulation pattern:initial grain boundary localization(Stage I)and intragranular propagation(Stage II).Ultimately,the intergranular cracks are initiated at triple junctions,and the twin boundaries exhibit superior mechanical stability compared with the large-angle grain boundaries.Deformation texture characteristics indicate the copper-type components,including C{112}<111¯>,S{123}<634¯>,and B{110}<11¯0>.The complete deformation sequence is as follows:cross-slip of soft-oriented slip systems→initiation of dislocation slip→strain partitioning through grain rotation→intergranular stress concentration→damage dominated by boundary cracking.The cross-scale deformation mechanism revealed in this study provides critical guidance for the crystal boundary engineering to optimize nickel-based superalloys.
基金Natural Science Foundation of Shaanxi Province (2023-JC-YB-312)。
文摘Ultrafine-grained(UFG)pure titanium was produced by equal channel angular pressing for 4 passes,followed by rotatory swaging at room temperature.The strain-controlled low-cycle fatigue tests of UFG and coarse-grained(CG)pure titanium were conducted by Instron electro-hydraulic servo fatigue testing machine in the strain amplitude range of 0.5%—1.1%at room temperature.Transmission electron microscope(TEM)and scanning electron microscope were used to investigate the microstructure and fracture surface of UFG pure titanium after fatigue tests.Results show that UFG pure titanium exhibits a longer low-cycle fatigue life,compared with the CG pure titanium.For example,at a total strain amplitude of 0.5%,UFG and CG pure titanium has fatigue life of 10850 and 4820 cycles,respectively.Significant cyclic softening occurs in UFG pure titanium,except in the case of a total strain amplitude of 0.5%.Hysteresis loop area is increased rapidly with the increase in strain amplitude.The fracture surface shows that the fatigue crack is initiated from the specimen surface.A series of fatigue striations and many microcracks exist in the propagation region.With the increase in strain amplitude,the predominant failure mode is transformed from ductile failure into quasi-cleavage failure.Dislocation slip is the main plastic deformation mechanism of UFG pure titanium during low-cycle fatigue deformation.
文摘This essay agrees that the two controversial characters on Slip 12 of the Hengxian 亘先 should be transcribed as ＂ ~ and ＂ ＂ and pronounced as ＂ji＂ 极. Secondly, with respect to six occurrences of the character ＂亘＂ （heng） on Slips 1-9 which Qiu Xigui 裘锡圭 reads as ＂极＂ （ji）, this essay holds that in the end it should be read as ＂恒＂ （heng）, and that the reading provided by Li Ling is acceptable. Therefore, that piece of bamboo slip writing can be named ＂恒先＂ （Hengxian）. Thirdly, ＂亘＂ （heng） and ＂亘先＂ （hengxian）, or ＂恒＂ （heng） and ＂恒先＂ （hengxian）, are two concepts, the latter of which is based on the former. ＂亘＂ （heng） is more fundamental and more important than ＂亘先＂ （hengxian）. Scholars mostly equate ＂恒＂ （heng） with ＂恒先＂ （hengxian）, and even regard ＂恒先＂ as the prior expression of this concept. One can hardly say that this is correct. In the bamboo writing, ＂恒＂ （heng） actually refers to ＂tian dao＂ 天道（heavenly dao）, rather than ＂dao＂ in the Laozi. The so-called ＂恒先＂ （hengxian） suggests the very commencement of the genesis and evolvement of Heavenly dao, which is somewhat equivalent to ＂taishi＂ 太始 （grand commencement） in the Huainanzi 淮南子. Fourthly, in the Hengxian, ＂恒＂ （heng） implies objective and natural laws, while ＂极＂ （ji） suggests ought-to-be rules. ＂极＂ （ji） in the bamboo writing is actually informed by ＂恒＂ （heng）.
基金funded by the Department of Geodetic Engineering,Faculty of Engineering,Universitas Gadjah Mada。
文摘Yogyakarta was struck by a devastating Mw6.3 earthquake,which intensified awareness about the seismic hazards in the region.This study investigates the kinematic slip rate and seismogenic depth of the northern segment of Opak Fault and an unmapped fault known as Ngalang Fault in Yogyakarta,utilizing Global Navigation Satellite System(GNSS)data collected between 2019 and 2023.By deploying a network of 12 GNSS stations alongside continuous observations from the InaCORS network,we perfo rmed a detailed geodetic analysis to discern current defo rmation patterns.To quantify the slip rate,we established a frame of reference using the Sundaland Block's rotational parameters and applied the Euler pole angular velocity to transform daily GNSS solutions acco rdingly.The findings reveal significant left-lateral strike-slip motion in the northern segment of Opak Fault,with a slip rate averaging 3 mm/yr and a locking depth of 2.1 km in Northern Segment,whereas the slip rate averages 1.1 mm/yr and the locking depth is estimated at 1 km in the Ngalang Fault,indicating active geological movements that may influence future seismicity.
基金supported by the National Natural Science Foundation of China(Nos.52061005,52261025)the Science and Technology Programs of Guizhou Province,China(Nos.YQK[2023]009,CXTD[2023]009)the Technology Innovation Leading Program of Shaanxi Province,China(No.2024ZCYYDP92)。
文摘The interrupted fatigue test method was utilized to investigate the damage evolution mechanism of the notch high-cycle fatigue(NHCF)in Ti-55531 alloy with a multilevel lamellar microstructure.The results reveal that significant microvoids and microcracks predominantly initiate at α/β interfaces under various notch root radii(R).Notably,even under larger R(0.75 mm),mutual interactions of stacking faults(SFs)−deformation twins,twins−twins,and SFs−SFs are observed.Furthermore,with decreasing R(0.34 and 0.14 mm),the volume fraction of SFs escalates significantly and twins are almost absent.Moreover,activated prismatic slip system decreases with a decrease in Schmidt factor and with the further decrease in R.Finally,strain localization near α/β interfaces contributes to the initiation of fatigue microcracks.
基金the Deep Earth Probe and Mineral Resources Exploration-National Science and Technology Major Project under Grant 2024ZD1000500。
文摘The shallow slip deficit(SSD)during strike-slip earthquakes raises a question of how the strain budget is accommodated over multiple cycles.However,the origin of variable SSD observed in different earthquakes is still under debate because each earthquake has its unique initial stress condition.Here,we derive the slip model of the 2021 M_(W) 7.4 Maduo earthquake in Qinghai,China,using multi-track radar images.Our results revealed that,in contrast to the large SSD on segments close to the epicenter,a much smaller SSD was observed at the west terminus of the rupture,where aftershock distribution indicates that the fault changes dip direction at 6 km depth.The 2021 Maduo earthquake thus represents an extraordinary case of significant along-strike SSD variation.After accounting for interseismic,postseismic,and diffuse off-fault deformation,we find that this variation is likely contributed by the along-dipping geometrical variation,implying that a multi-segment earthquake may leave heterogeneous stress condition on the fault with different amounts of SSD.
