Additive manufacturing(AM)has become a versatile and diverse technology that has a significant impact on manufacturing processes.Therefore,ceramic materials have been developed rapidly for use in AM processes.Vat phot...Additive manufacturing(AM)has become a versatile and diverse technology that has a significant impact on manufacturing processes.Therefore,ceramic materials have been developed rapidly for use in AM processes.Vat photopolymerization(VPP)is an AM method that enables the production of dense ceramic components with increased dimensional accuracy.In particular,it facilitates the fabrication of small and intricately shaped parts.This review summarizes the research advancements in ceramics prepared via VPP.Special attention is paid to the current status of relevant areas,such as slurry preparation and process optimization,as well as the form-ing mechanisms,debinding,sintering,performance characterization,and use of VPP-based ceramics.Moreover,earlier studies performed by our research group on numerous VPP-based ceramic aspects are considered.In ad-dition,a concise overview of the differences in forming principles,mechanical performance,advantages,and disadvantages between VPP-based ceramics and conventional colloidal-forming ceramics is presented.Finally,the challenges and prospects of VPP-based ceramics are discussed.展开更多
This research builds an index to describe the inequality in health care expenditure related to pollution,and the measurement with Chinese provincial data set suggests that health care expenditure inequality related to...This research builds an index to describe the inequality in health care expenditure related to pollution,and the measurement with Chinese provincial data set suggests that health care expenditure inequality related to pollution is obvious negative,which confirms that residents located in high-polluted areas cannot get the better health care resources.Meanwhile,the absolute value of health care expenditure inequality related to pollution is even larger than that related to income,which suggests the inequality related to pollution cannot be ignored.展开更多
In this study,the chemical precipitation coating(CP)process was creatively integrated with DLP-stereolithography based 3D printing for refining and homogenizing the microstructure of 3D printed Al_(2)O_(3) ceramic.Bas...In this study,the chemical precipitation coating(CP)process was creatively integrated with DLP-stereolithography based 3D printing for refining and homogenizing the microstructure of 3D printed Al_(2)O_(3) ceramic.Based on this novel approach,Al_(2)O_(3)powder was coated with a homogeneous layer of amorphous Y2O3,with the coated AI2O3 powder found to make the microstructure of 3D printed Al_(2)O_(3) ceramic more uniform and refined,as compared with the conventional mechanical mixing(MM)of Al_(2)O_(3) and Y_(2)O_(3) powders.The grain size of Al_(2)O_(3) in Sample CP is 64.44%and 51.43%lower than those in the monolithic Al_(2)O_(3) ceramic and Sample MM,respectively.Sample CP has the highest flexural strength of 455.37±32.17 MPa,which is 14.85%and 25.45%higher than those of Samples MM and AL,respectively;also Sample CP has the highest Weibull modulus of 16.88 among the three kinds of samples.Moreover,the fine grained Sample CP has a close thermal conductivity to the coarse grained Sample MM because of the changes in morphology of Y_(3)Al_(5)O_(12) phase from semi-connected(Sample MM)to isolated(Sample CP).Finally,specially designed fin-type Al_(2)O_(3) ceramic heat sinks were successfully fabricated via the novel integrated process,which has been proven to be an effective method for fabricating complex-shaped Al_(2)O_(3) ceramic components with enhanced flexural strength and reliability.展开更多
Pollen, as an important index of the paleoenvironment and ancient human agricultural activities, is also one of the significant indicators for research on buckwheat agriculture. In order to test buckwheat pollen dispe...Pollen, as an important index of the paleoenvironment and ancient human agricultural activities, is also one of the significant indicators for research on buckwheat agriculture. In order to test buckwheat pollen dispersal during each crop processing stage, we applied traditional processing simulation experiments of buckwheat crops in a modern village, to collect aerial pollen and perform statistical analysis. The result has shown that the distribution of buckwheat pollen in residential areas is closely related to human processing behaviour. Among all the processing procedures, pollen release rate is highest in the threshing and the sieving stages. The redistribution and burial of pollen during crop processing is an important reason for the prominent increase of crop pollen concentration in the cultural layer. Not only can it indicate the cultivation and processing behaviour of humans but also provide a basis for identifying the crop processing remains in archaeological sites and assessing the intensity of agricultural activities.展开更多
基金supported by Key-Area Research and Devel-opment Program of Guangdong Province of China(Grant No.2020B090923002)Guangdong Basic and Applied Basic Research Foun-dation of China(Grant No.2019B1515130005)+1 种基金Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program of China(Grant No.2017BT01C169)Foshan Science and Technology Innovation Team Project of China(Grant No.FS0AA-KJ919-4402-0023).
文摘Additive manufacturing(AM)has become a versatile and diverse technology that has a significant impact on manufacturing processes.Therefore,ceramic materials have been developed rapidly for use in AM processes.Vat photopolymerization(VPP)is an AM method that enables the production of dense ceramic components with increased dimensional accuracy.In particular,it facilitates the fabrication of small and intricately shaped parts.This review summarizes the research advancements in ceramics prepared via VPP.Special attention is paid to the current status of relevant areas,such as slurry preparation and process optimization,as well as the form-ing mechanisms,debinding,sintering,performance characterization,and use of VPP-based ceramics.Moreover,earlier studies performed by our research group on numerous VPP-based ceramic aspects are considered.In ad-dition,a concise overview of the differences in forming principles,mechanical performance,advantages,and disadvantages between VPP-based ceramics and conventional colloidal-forming ceramics is presented.Finally,the challenges and prospects of VPP-based ceramics are discussed.
文摘This research builds an index to describe the inequality in health care expenditure related to pollution,and the measurement with Chinese provincial data set suggests that health care expenditure inequality related to pollution is obvious negative,which confirms that residents located in high-polluted areas cannot get the better health care resources.Meanwhile,the absolute value of health care expenditure inequality related to pollution is even larger than that related to income,which suggests the inequality related to pollution cannot be ignored.
基金supported by the Local Innovative and Research Team Project of Guangdong Province(Grant No.2017BT01C169)the Opening Project of State Key Laboratory of Green Building Materials(Grant No.2019GBM03)+2 种基金the Guangdong Basic and Applied Basic Research Foundation(Grant No.2020A1515010004)the Natural Science Foundation of Guangdong Province(Grant No.2018A030313353)the Science and Technology Program of Guangzhou(Grant No.201904010357).
文摘In this study,the chemical precipitation coating(CP)process was creatively integrated with DLP-stereolithography based 3D printing for refining and homogenizing the microstructure of 3D printed Al_(2)O_(3) ceramic.Based on this novel approach,Al_(2)O_(3)powder was coated with a homogeneous layer of amorphous Y2O3,with the coated AI2O3 powder found to make the microstructure of 3D printed Al_(2)O_(3) ceramic more uniform and refined,as compared with the conventional mechanical mixing(MM)of Al_(2)O_(3) and Y_(2)O_(3) powders.The grain size of Al_(2)O_(3) in Sample CP is 64.44%and 51.43%lower than those in the monolithic Al_(2)O_(3) ceramic and Sample MM,respectively.Sample CP has the highest flexural strength of 455.37±32.17 MPa,which is 14.85%and 25.45%higher than those of Samples MM and AL,respectively;also Sample CP has the highest Weibull modulus of 16.88 among the three kinds of samples.Moreover,the fine grained Sample CP has a close thermal conductivity to the coarse grained Sample MM because of the changes in morphology of Y_(3)Al_(5)O_(12) phase from semi-connected(Sample MM)to isolated(Sample CP).Finally,specially designed fin-type Al_(2)O_(3) ceramic heat sinks were successfully fabricated via the novel integrated process,which has been proven to be an effective method for fabricating complex-shaped Al_(2)O_(3) ceramic components with enhanced flexural strength and reliability.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41471167 & 41730319)the National Basic Research Program of China (Grant No. 2015CB953803)
文摘Pollen, as an important index of the paleoenvironment and ancient human agricultural activities, is also one of the significant indicators for research on buckwheat agriculture. In order to test buckwheat pollen dispersal during each crop processing stage, we applied traditional processing simulation experiments of buckwheat crops in a modern village, to collect aerial pollen and perform statistical analysis. The result has shown that the distribution of buckwheat pollen in residential areas is closely related to human processing behaviour. Among all the processing procedures, pollen release rate is highest in the threshing and the sieving stages. The redistribution and burial of pollen during crop processing is an important reason for the prominent increase of crop pollen concentration in the cultural layer. Not only can it indicate the cultivation and processing behaviour of humans but also provide a basis for identifying the crop processing remains in archaeological sites and assessing the intensity of agricultural activities.
