Based on first-order kinetics of hydrolysis process, biodegradation of municipal solid waste （MSW） is assumed to obey a first-order decay equation which can take the direct effect of water content on biodegradation ...Based on first-order kinetics of hydrolysis process, biodegradation of municipal solid waste （MSW） is assumed to obey a first-order decay equation which can take the direct effect of water content on biodegradation into account. Hydraulic model is an unsaturated-saturated flow model using mass conservation equations for fluids. Mechanical compression of MSW is ex- pressed by a stress-age coupled compression model. Through above models, a one-dimensional （I-D） bio-hydro-mechanical coupled model is established to analyze solid-liquid-gas interactions in landfilled MSW. Values of all the model parameters for current typical Chinese MSW are determined. Numerical analysis of a hypothetical waste sample in a closed system shows that gas pressure and gas concentration is extremely large which might cause severe gas explosion problem. Total gas production is about 267.0 m3 per wet ton of fresh wastes. For another hypothetical landfilled MSW layer, the coupled model predicts a dis- sipation of gas pressure during passive gas collection process. Annual gas production is large at the beginning of biodegradation, and then decreases with time. Surface settlement of the wastes increases quickly initially and then becomes stable with a compression strain of about 0.32 after 20 years.展开更多
A novel solid-liquid interdiffusion(SLID)bonding method with the assistance of temperature gradient(TG)was carried out to bonding Cu and Ni substrates with Sn as interlayer.The element distribution and grain morpholog...A novel solid-liquid interdiffusion(SLID)bonding method with the assistance of temperature gradient(TG)was carried out to bonding Cu and Ni substrates with Sn as interlayer.The element distribution and grain morphology of interfacial intermetallic compound(IMC)in Cu/Sn/Ni micro-joints during both SLID and TG-SLID bonding and in the final Cu/(Cu,Ni)_(6)Sn_(5)/Ni full IMC micro-joints were analyzed.Under the effect of Cu-Ni cross-interaction,interfacial(Cu,Ni)_(6)Sn_(5) dominated the IMC growth at all the interfaces.The morphology of the(Cu,Ni)_(6)Sn_(5) grains was closely related to Ni content with three levels of low,medium and high.The full IMC micro-joints consisted of L-(Cu,Ni)_(6) Sn_(5),M-(Cu,Ni)_(6)Sn_(5) and H-(Cu,Ni)_(6)Sn_(5) grains after SLID bonding or TG-SLID bonding with Ni as hot end,while only L-(Cu,Ni)_(6)Sn_(5) grains after TG-SLID bonding with Cu as hot end,showing that the direction of TG had a remarkably effect on the growth and morphology of the interfacial(Cu,Ni)_(6)Sn_(5) during TG-SLID bonding.Thermodynamic analysis revealed the key molar latent heat and critical Ni content between fine-rounded-like(Cu,Ni)_(6)Sn_(5) and block-like(Cu,Ni)_(6)Sn_(5) were 17,725.4 J and 11.0 at.%at 260℃,respectively.Moreover,the growth kinetic of the interfacial IMC was analyzed in detail during bonding with and without TG.Under the combination of TG and Cu-Ni cross-interaction,void-free full IMC micro-joints were fast formed by TG-SLID bonding with Cu as hot end.This bonding method may present a feasible solution to solve the problems of low formation efficiency and inevitable Cu_(3) Sn growth of full IMC joints for 3 D packaging applications.展开更多
Friction is a fundamental force that impacts almost all interface-related applications.Over the past decade,there is a revival in our basic understanding and practical applications of the friction.In this review,we di...Friction is a fundamental force that impacts almost all interface-related applications.Over the past decade,there is a revival in our basic understanding and practical applications of the friction.In this review,we discuss the recent progress on solid–liquid interfacial friction from the perspective of interfaces.We first discuss the fundamentals and theoretical evolution of solid–liquid interfacial friction based on both bulk interactions and molecular interactions.Then,we summarize the interfacial friction regulation strategies manifested in both natural surfaces and artificial systems,focusing on how liquid,solid,gas,and hydrodynamic coupling actions mediate interfacial friction.Next,we discuss some practical applications that are inhibited or reinforced by interfacial friction.At last,we present the challenges to further understand and regulate interfacial friction.展开更多
Elastic composites containing liquid inclusions exist widely in nature and engineering fields. The volumetric response of liquid inclusions is important in many cases, such as an isolated cell embedded in an extracell...Elastic composites containing liquid inclusions exist widely in nature and engineering fields. The volumetric response of liquid inclusions is important in many cases, such as an isolated cell embedded in an extracellular matrix and an oil pocket embedded within shale. In this study, we developed a model for describing the volumetric response of an ellipsoidal liquid inclusion. Specifically, we investigated the volumetric response of an ellipsoidal liquid inclusion embedded in a three-dimensional (3D) matrix through an analytical expression of the volumetric response. We performed parametric analysis and found that loading along the shortest axis can induce the most volume change, while loading along the longest axis can induce the least volume change. We also found that the volumetric response decreases with increasing Poisson ratio of the matrix. These results could be used to understand some cell behavior in a 3D matrix, for example, cell alignment under mechanical load.展开更多
The interaction of particles with a solid-liquid interface during solidification of metal matrix composites has been investigated theoretically in this paper.Owing to the presence of particles in the melt,the shape of...The interaction of particles with a solid-liquid interface during solidification of metal matrix composites has been investigated theoretically in this paper.Owing to the presence of particles in the melt,the shape of the solidification front and solute concentration field in front of solidification interface have been disturbed The thermodynamic method was employed,and a mathematical expression of the shape of the solidification interface and solute concentration field were deduced.Meanwhile,a theory is developed for evaluation of critical velocities of particles pushed by the solidification interface.A numerical simulation is done in which the critical velocity is evaluated as a function of particle size,thermal conductivity,diffusion coefficient,temperature gradient at the solidification front,the solid-liquid interfacial energy and the melt viscosity.The critical velocity is shown to be closely linked to the shape of the solidification interface and solute concentration field, and hence all the parameters also affect the shape of the solidification interface and solute concentration field of the front.展开更多
This paper studies the problem of free bending vibration of annular cylindricaltank partially filled with liquid in the consideration of surface wave.The exactformulae of the mode shape functions and frequencies are d...This paper studies the problem of free bending vibration of annular cylindricaltank partially filled with liquid in the consideration of surface wave.The exactformulae of the mode shape functions and frequencies are deduced.Results can beobtained by means of computer.The analysis shows that the effect of liquid on vibration of annular cylindrical tank is equivalent to different generalized distributivemasses attached to inner and outer cylinders respectively.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos.51010008, 10972195)the National Basic Research Program of China ("973" Project) (Grant No.2012CB719800)
文摘Based on first-order kinetics of hydrolysis process, biodegradation of municipal solid waste （MSW） is assumed to obey a first-order decay equation which can take the direct effect of water content on biodegradation into account. Hydraulic model is an unsaturated-saturated flow model using mass conservation equations for fluids. Mechanical compression of MSW is ex- pressed by a stress-age coupled compression model. Through above models, a one-dimensional （I-D） bio-hydro-mechanical coupled model is established to analyze solid-liquid-gas interactions in landfilled MSW. Values of all the model parameters for current typical Chinese MSW are determined. Numerical analysis of a hypothetical waste sample in a closed system shows that gas pressure and gas concentration is extremely large which might cause severe gas explosion problem. Total gas production is about 267.0 m3 per wet ton of fresh wastes. For another hypothetical landfilled MSW layer, the coupled model predicts a dis- sipation of gas pressure during passive gas collection process. Annual gas production is large at the beginning of biodegradation, and then decreases with time. Surface settlement of the wastes increases quickly initially and then becomes stable with a compression strain of about 0.32 after 20 years.
基金financially supported by the National Natural Science Foundation of China(No.52075072)the Fundamental Research Funds for the Central Universities(No.DUT20JC46)。
文摘A novel solid-liquid interdiffusion(SLID)bonding method with the assistance of temperature gradient(TG)was carried out to bonding Cu and Ni substrates with Sn as interlayer.The element distribution and grain morphology of interfacial intermetallic compound(IMC)in Cu/Sn/Ni micro-joints during both SLID and TG-SLID bonding and in the final Cu/(Cu,Ni)_(6)Sn_(5)/Ni full IMC micro-joints were analyzed.Under the effect of Cu-Ni cross-interaction,interfacial(Cu,Ni)_(6)Sn_(5) dominated the IMC growth at all the interfaces.The morphology of the(Cu,Ni)_(6)Sn_(5) grains was closely related to Ni content with three levels of low,medium and high.The full IMC micro-joints consisted of L-(Cu,Ni)_(6) Sn_(5),M-(Cu,Ni)_(6)Sn_(5) and H-(Cu,Ni)_(6)Sn_(5) grains after SLID bonding or TG-SLID bonding with Ni as hot end,while only L-(Cu,Ni)_(6)Sn_(5) grains after TG-SLID bonding with Cu as hot end,showing that the direction of TG had a remarkably effect on the growth and morphology of the interfacial(Cu,Ni)_(6)Sn_(5) during TG-SLID bonding.Thermodynamic analysis revealed the key molar latent heat and critical Ni content between fine-rounded-like(Cu,Ni)_(6)Sn_(5) and block-like(Cu,Ni)_(6)Sn_(5) were 17,725.4 J and 11.0 at.%at 260℃,respectively.Moreover,the growth kinetic of the interfacial IMC was analyzed in detail during bonding with and without TG.Under the combination of TG and Cu-Ni cross-interaction,void-free full IMC micro-joints were fast formed by TG-SLID bonding with Cu as hot end.This bonding method may present a feasible solution to solve the problems of low formation efficiency and inevitable Cu_(3) Sn growth of full IMC joints for 3 D packaging applications.
基金This work was supported by the funding from Health@InnoHK(Hong Kong Centre for Cerebro-cardiovascular Health Engineering(COCHE)),the Innovation and Technology Commission,the Government of the Hong Kong Special Administrative Region of the People’s Republic of China,the National Natural Science Foundation of China(12102250)China Postdoctoral Science Foundation(2020TQ0190 and 2020M681290).
文摘Friction is a fundamental force that impacts almost all interface-related applications.Over the past decade,there is a revival in our basic understanding and practical applications of the friction.In this review,we discuss the recent progress on solid–liquid interfacial friction from the perspective of interfaces.We first discuss the fundamentals and theoretical evolution of solid–liquid interfacial friction based on both bulk interactions and molecular interactions.Then,we summarize the interfacial friction regulation strategies manifested in both natural surfaces and artificial systems,focusing on how liquid,solid,gas,and hydrodynamic coupling actions mediate interfacial friction.Next,we discuss some practical applications that are inhibited or reinforced by interfacial friction.At last,we present the challenges to further understand and regulate interfacial friction.
基金the National Natural Science Foundation of China (Grants 11522219 and 11532009)the National Institutes of Health (Grant U01EB016422)+1 种基金the National Science Foundation through the ScienceTechnology Center for Engineering Mechanobiology (Grant CMMI 1548571).
文摘Elastic composites containing liquid inclusions exist widely in nature and engineering fields. The volumetric response of liquid inclusions is important in many cases, such as an isolated cell embedded in an extracellular matrix and an oil pocket embedded within shale. In this study, we developed a model for describing the volumetric response of an ellipsoidal liquid inclusion. Specifically, we investigated the volumetric response of an ellipsoidal liquid inclusion embedded in a three-dimensional (3D) matrix through an analytical expression of the volumetric response. We performed parametric analysis and found that loading along the shortest axis can induce the most volume change, while loading along the longest axis can induce the least volume change. We also found that the volumetric response decreases with increasing Poisson ratio of the matrix. These results could be used to understand some cell behavior in a 3D matrix, for example, cell alignment under mechanical load.
文摘The interaction of particles with a solid-liquid interface during solidification of metal matrix composites has been investigated theoretically in this paper.Owing to the presence of particles in the melt,the shape of the solidification front and solute concentration field in front of solidification interface have been disturbed The thermodynamic method was employed,and a mathematical expression of the shape of the solidification interface and solute concentration field were deduced.Meanwhile,a theory is developed for evaluation of critical velocities of particles pushed by the solidification interface.A numerical simulation is done in which the critical velocity is evaluated as a function of particle size,thermal conductivity,diffusion coefficient,temperature gradient at the solidification front,the solid-liquid interfacial energy and the melt viscosity.The critical velocity is shown to be closely linked to the shape of the solidification interface and solute concentration field, and hence all the parameters also affect the shape of the solidification interface and solute concentration field of the front.
文摘This paper studies the problem of free bending vibration of annular cylindricaltank partially filled with liquid in the consideration of surface wave.The exactformulae of the mode shape functions and frequencies are deduced.Results can beobtained by means of computer.The analysis shows that the effect of liquid on vibration of annular cylindrical tank is equivalent to different generalized distributivemasses attached to inner and outer cylinders respectively.
