Friction and wear performance is critical for dental materials which are inevitably subject to reciprocating friction against opposing teeth in applications.Here in-vitro friction and wear behavior of bioinspired cera...Friction and wear performance is critical for dental materials which are inevitably subject to reciprocating friction against opposing teeth in applications.Here in-vitro friction and wear behavior of bioinspired ceramic-polymer composites,which possess nacre-like lamellar and brick-and-mortar architectures and resemble human teeth in their stiffness and hardness,against human tooth enamel were quantitatively investigated to imitate actual service conditions in line with standardized testing configuration.The composites were revealed to exhibit different wear mechanisms and lead to differing extents of wear to the opposing tooth enamel depending on their specific architectural types and orientations.In particular,the brick-and-mortar architecture displayed much less wear than the lamellar one,without obviously roughening the contact surfaces with enamel owing to its high ceramic content,and as such did not accelerate the wear of enamel as compared to smooth ceramics.Such characteristics,combined with its unique stiffness and hardness matching those of human enamel as well as the good fracture toughness and machinability,endow the composite with a promising potential for dental applications.This work may provide an experimental basis to this end and may also give insights towards designing new bioinspired wear-resistant materials for reducing friction and wear.展开更多
Nowadays,mild hypothermia is widely used in the fields of post-cardiac arrest resuscitation,stroke,cerebral hemorrhage,large-scale cerebral infarction,and craniocerebral injury.In this paper,a locally mixed sub-low te...Nowadays,mild hypothermia is widely used in the fields of post-cardiac arrest resuscitation,stroke,cerebral hemorrhage,large-scale cerebral infarction,and craniocerebral injury.In this paper,a locally mixed sub-low temperature device is designed,and the cold and hot water mixing experiment is used to simulate the human blood transfer process.To set a foundation for the optimization of the heat transfer system,the static characteristics are analyzed by building the mathematic model and setting up the experimental station.In addition,the affection of several key structure parameters is researched.Through experimental and simulation studies,it can be concluded that,firstly,the mathematical model proved to be effective.Secondly,the results of simulation experiments show that 14.52℃ refrigeration can reduce the original temperature of 33.42℃ to 32.02℃,and the temperature of refrigerated blood rises to 18.64℃,and the average error is about 0.3℃.Thirdly,as the thermal conductivity of the vascular sheath increases,the efficiency of the heat exchange system also increases significantly.Finally,as the input cold blood flow rate increases,the mass increases and the temperature of the mixed blood temperature decreases.It provides a research basis for subsequent research on local fixed-point sub-low temperature control technology.展开更多
基金financially supported by the National Key R&D Program of China(No.2020YFA0710404)the National Natural Science Foundation of China(Nos.52173269 and 51871216)+1 种基金the Liaoning Revitalization Talents Programthe Youth Innovation Promotion Association CAS。
文摘Friction and wear performance is critical for dental materials which are inevitably subject to reciprocating friction against opposing teeth in applications.Here in-vitro friction and wear behavior of bioinspired ceramic-polymer composites,which possess nacre-like lamellar and brick-and-mortar architectures and resemble human teeth in their stiffness and hardness,against human tooth enamel were quantitatively investigated to imitate actual service conditions in line with standardized testing configuration.The composites were revealed to exhibit different wear mechanisms and lead to differing extents of wear to the opposing tooth enamel depending on their specific architectural types and orientations.In particular,the brick-and-mortar architecture displayed much less wear than the lamellar one,without obviously roughening the contact surfaces with enamel owing to its high ceramic content,and as such did not accelerate the wear of enamel as compared to smooth ceramics.Such characteristics,combined with its unique stiffness and hardness matching those of human enamel as well as the good fracture toughness and machinability,endow the composite with a promising potential for dental applications.This work may provide an experimental basis to this end and may also give insights towards designing new bioinspired wear-resistant materials for reducing friction and wear.
基金Supported by Open Research Project of the State Key Laboratory of Media Convergence and Communication,Communication University of China(Grant No.SKLMCC2020KF002)Fundamental Research Funds for Central Public Welfare Research Institutes,National Key Research and Development Project(Grant No.2019YFC0121700)China Postdoctoral Science Foundation(Grant No.2019M660392).
文摘Nowadays,mild hypothermia is widely used in the fields of post-cardiac arrest resuscitation,stroke,cerebral hemorrhage,large-scale cerebral infarction,and craniocerebral injury.In this paper,a locally mixed sub-low temperature device is designed,and the cold and hot water mixing experiment is used to simulate the human blood transfer process.To set a foundation for the optimization of the heat transfer system,the static characteristics are analyzed by building the mathematic model and setting up the experimental station.In addition,the affection of several key structure parameters is researched.Through experimental and simulation studies,it can be concluded that,firstly,the mathematical model proved to be effective.Secondly,the results of simulation experiments show that 14.52℃ refrigeration can reduce the original temperature of 33.42℃ to 32.02℃,and the temperature of refrigerated blood rises to 18.64℃,and the average error is about 0.3℃.Thirdly,as the thermal conductivity of the vascular sheath increases,the efficiency of the heat exchange system also increases significantly.Finally,as the input cold blood flow rate increases,the mass increases and the temperature of the mixed blood temperature decreases.It provides a research basis for subsequent research on local fixed-point sub-low temperature control technology.
