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 undiffer...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
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
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
IN 1968, I, a middle school graduate, went to live and work as a farmer in Dongru, a small mountain village in north China. Later, I became a shop assistant in the county town. I spent nine years of my life there—fro...IN 1968, I, a middle school graduate, went to live and work as a farmer in Dongru, a small mountain village in north China. Later, I became a shop assistant in the county town. I spent nine years of my life there—from age 17 to 26. The memory of those years has begun to fade; only some words are left here as a reminder of my youth. In May, 1971, the county’s settlement office began transferring the urban educated youth from the countryside into the county-town.展开更多
This communication reports,the flow of viscoelastic nanofluid with third order slip flow condition,Cattaneo-Christov heat and mass diffusion model.The joined non-linear ordinary differential equations(ODEs)were acquir...This communication reports,the flow of viscoelastic nanofluid with third order slip flow condition,Cattaneo-Christov heat and mass diffusion model.The joined non-linear ordinary differential equations(ODEs)were acquired from the partial differential equations,which are resulting from conservation of momentum,energy and species.By means of similarity transformations these ODEs were alerted into dimensionless form and solved numerically by means of bvp4c solver.The effects of different parameters on velocity,temperature,and concentration profiles were examined and discussed in depth by means of graphs and tables.The outcomes indicate that the velocity profile along both x and y directions augment with higher values of viscoelastic parameter.The results also confirm that an increment in the values of ratio parameter tends to grow up the velocity profile alongside y-direction.However,the velocity profile along x-direction slows down with increment in the value of third order slip parameter.Also,the results illustrate that diminution in temperature is observed for higher Sc in the region of boundary layer.Besides,both temperature and concentration can be improved via higher Biot number.The upshots also portrayed that the local skin friction coefficient augmented within mounting values of viscoelastic fluid parameter.Furthermore,for finer values of Biot number both local Nusselt number and the local Sherwood number are enlarged.In addition,the most favorable agreement is observed among the results of the present study and those of the earlier studies.展开更多
The thermal and velocity slips of boundary layer of Williamson nanofluid over a stretching sheet are studied numerically.Buongiorno model is used to explore the heat transfer phenomena caused by Brownian motion and th...The thermal and velocity slips of boundary layer of Williamson nanofluid over a stretching sheet are studied numerically.Buongiorno model is used to explore the heat transfer phenomena caused by Brownian motion and thermophoresis.Using similarity transformations,the governing equations are reduced to a set of nonlinear ordinary differential equations(ODEs).These equations are solved numerically by using Shooting method.The effects of non-Newtonian Williamson parameter,velocity and thermal slip parameters,Prandtl number,Brownian parameter,Schmidt number,Lewis number,Brownian motion parameter,thermophoresis parameter on velocity,temperature and concentration fields are shown graphically and discussed.The results found that the thickness of boundary layer decreases as the slip and thermal factor parameter increases.Further,present results indicate that the nanofluid temperature and concentration are enhanced with a rise of Williamson parameter.The Nusselt number is reduced with an increase of the Lewis and Prandtl numbers.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.
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）.
文摘IN 1968, I, a middle school graduate, went to live and work as a farmer in Dongru, a small mountain village in north China. Later, I became a shop assistant in the county town. I spent nine years of my life there—from age 17 to 26. The memory of those years has begun to fade; only some words are left here as a reminder of my youth. In May, 1971, the county’s settlement office began transferring the urban educated youth from the countryside into the county-town.
文摘This communication reports,the flow of viscoelastic nanofluid with third order slip flow condition,Cattaneo-Christov heat and mass diffusion model.The joined non-linear ordinary differential equations(ODEs)were acquired from the partial differential equations,which are resulting from conservation of momentum,energy and species.By means of similarity transformations these ODEs were alerted into dimensionless form and solved numerically by means of bvp4c solver.The effects of different parameters on velocity,temperature,and concentration profiles were examined and discussed in depth by means of graphs and tables.The outcomes indicate that the velocity profile along both x and y directions augment with higher values of viscoelastic parameter.The results also confirm that an increment in the values of ratio parameter tends to grow up the velocity profile alongside y-direction.However,the velocity profile along x-direction slows down with increment in the value of third order slip parameter.Also,the results illustrate that diminution in temperature is observed for higher Sc in the region of boundary layer.Besides,both temperature and concentration can be improved via higher Biot number.The upshots also portrayed that the local skin friction coefficient augmented within mounting values of viscoelastic fluid parameter.Furthermore,for finer values of Biot number both local Nusselt number and the local Sherwood number are enlarged.In addition,the most favorable agreement is observed among the results of the present study and those of the earlier studies.
基金The authors gratefully acknowledge the financial supports received from Ministry of Higher Education,University Malaysia Pahang(UMP),Malaysia,through vote number RDU 150101 and RDU 170358.The second author would like to acknowledge Ton Duc Thang University,Ho Chi Minh City,Vietnam for the financial support.
文摘The thermal and velocity slips of boundary layer of Williamson nanofluid over a stretching sheet are studied numerically.Buongiorno model is used to explore the heat transfer phenomena caused by Brownian motion and thermophoresis.Using similarity transformations,the governing equations are reduced to a set of nonlinear ordinary differential equations(ODEs).These equations are solved numerically by using Shooting method.The effects of non-Newtonian Williamson parameter,velocity and thermal slip parameters,Prandtl number,Brownian parameter,Schmidt number,Lewis number,Brownian motion parameter,thermophoresis parameter on velocity,temperature and concentration fields are shown graphically and discussed.The results found that the thickness of boundary layer decreases as the slip and thermal factor parameter increases.Further,present results indicate that the nanofluid temperature and concentration are enhanced with a rise of Williamson parameter.The Nusselt number is reduced with an increase of the Lewis and Prandtl numbers.
