Thermal print head heating real-time temperature fluctuations are too large,often causing damage to the print head heating point,resulting in poor print quality and unsatisfactory print results.Therefore,to improve th...Thermal print head heating real-time temperature fluctuations are too large,often causing damage to the print head heating point,resulting in poor print quality and unsatisfactory print results.Therefore,to improve the stability of the thermal print head during printing,and at the same time to solve the inefficiency of the traditional single-chip microcomputer control of the thermal print head heating method,a field programmable gate array-based thermal print head heating control method is proposed.To control the core,the intelligent fuzzy Proportional-Integral-Differential(PID)control algorithm is used to ensure that the temperature of the print head can be stabilized quickly.Through simulation and experimental verification,it is shown that the intelligent fuzzy PID control algorithm greatly improves the temperature stabilization effect,and the time required to reach stability short not only improve the printing accuracy but also extend the life of the print head.展开更多
The research of purely organic materials with long afterglow has drawn more and more attention,especially for those with stimulus‐response characteristic.So far,this kind of material is really very scarce and their p...The research of purely organic materials with long afterglow has drawn more and more attention,especially for those with stimulus‐response characteristic.So far,this kind of material is really very scarce and their performance is not good enough.In this study,we successfully developed an efficient heatingresponsive room‐temperature phosphorescence material with phosphorescence efficiency and lifetime up to 13.4%and 2.08 s through the simple host–guest doping strategy.Further on,by introducing the additional energy acceptor of fluorescein with concentration‐dependent emission to construct ternary doping systems,the afterglow color was extended from blue to yellow.Accordingly,the multicolor thermal printings have been easily realized,showing the great practical application prospects.展开更多
A thermal via has been used to enhance the heat transfer through the printed circuit board (PCB). Because the thermal conductivity of a dielectric material is very low, the array of metal vias is placed to make therma...A thermal via has been used to enhance the heat transfer through the printed circuit board (PCB). Because the thermal conductivity of a dielectric material is very low, the array of metal vias is placed to make thermal paths in the PCB. This paper describes the numerical analysis of the PCB having metal vias and focuses on the heat transfer characteristics under the nonisothermal boundary conditions. The mathematical model of the PCB has the metal vias between two metal sheets. Under 2nd and 3rd kinds of boundary conditions, the temperature distribution is obtained numerically by changing the design parameters. The discussion is also made on the effective thermal conductivity of the PCB. In industry, the use of effective thermal conductivity is convenient for thermal engineers because it simplifies the calculation process, that is, the composite board can be modeled as a homogeneous medium. From the numerical results, it is confirmed that the placement of metal sheets and the population of metal vias are important factors to dominate the heat transfer characteristics of the PCB. It is also shown that although the nonisothermal boundary conditions are applied at the boundary surface, the temperature difference between the heated and the cooled section is almost uniform when the metal vias are populated densely with the metal sheets. In this case, the effective thermal conductivity of the PCB is found to be the same irrespective of the boundary conditions, that is, whether the isothermal or the nonisothermal boundary conditions are applied.展开更多
文摘Thermal print head heating real-time temperature fluctuations are too large,often causing damage to the print head heating point,resulting in poor print quality and unsatisfactory print results.Therefore,to improve the stability of the thermal print head during printing,and at the same time to solve the inefficiency of the traditional single-chip microcomputer control of the thermal print head heating method,a field programmable gate array-based thermal print head heating control method is proposed.To control the core,the intelligent fuzzy Proportional-Integral-Differential(PID)control algorithm is used to ensure that the temperature of the print head can be stabilized quickly.Through simulation and experimental verification,it is shown that the intelligent fuzzy PID control algorithm greatly improves the temperature stabilization effect,and the time required to reach stability short not only improve the printing accuracy but also extend the life of the print head.
基金National Natural Science Foundation of China,Grant/Award Number:51903188Natural Science Foundation of Tianjin City,Grant/Award Number:19JCQNJC04500The starting Grants of Tianjin University and Tianjin Government。
文摘The research of purely organic materials with long afterglow has drawn more and more attention,especially for those with stimulus‐response characteristic.So far,this kind of material is really very scarce and their performance is not good enough.In this study,we successfully developed an efficient heatingresponsive room‐temperature phosphorescence material with phosphorescence efficiency and lifetime up to 13.4%and 2.08 s through the simple host–guest doping strategy.Further on,by introducing the additional energy acceptor of fluorescein with concentration‐dependent emission to construct ternary doping systems,the afterglow color was extended from blue to yellow.Accordingly,the multicolor thermal printings have been easily realized,showing the great practical application prospects.
文摘A thermal via has been used to enhance the heat transfer through the printed circuit board (PCB). Because the thermal conductivity of a dielectric material is very low, the array of metal vias is placed to make thermal paths in the PCB. This paper describes the numerical analysis of the PCB having metal vias and focuses on the heat transfer characteristics under the nonisothermal boundary conditions. The mathematical model of the PCB has the metal vias between two metal sheets. Under 2nd and 3rd kinds of boundary conditions, the temperature distribution is obtained numerically by changing the design parameters. The discussion is also made on the effective thermal conductivity of the PCB. In industry, the use of effective thermal conductivity is convenient for thermal engineers because it simplifies the calculation process, that is, the composite board can be modeled as a homogeneous medium. From the numerical results, it is confirmed that the placement of metal sheets and the population of metal vias are important factors to dominate the heat transfer characteristics of the PCB. It is also shown that although the nonisothermal boundary conditions are applied at the boundary surface, the temperature difference between the heated and the cooled section is almost uniform when the metal vias are populated densely with the metal sheets. In this case, the effective thermal conductivity of the PCB is found to be the same irrespective of the boundary conditions, that is, whether the isothermal or the nonisothermal boundary conditions are applied.
