Cutting tools are known as the“productivity”of the manufacturing industry,which affects the production efficiency and quality of the workpiece,and has become the focus of research and attention in academia and indus...Cutting tools are known as the“productivity”of the manufacturing industry,which affects the production efficiency and quality of the workpiece,and has become the focus of research and attention in academia and industry.However,traditional cutting tools often suffer from adhesion or wear during the cutting process,which considerably reduces the cutting efficiency and service life of the tools,and makes it difficult to meet current production requirements.To solve the above problems,scholars have introduced bionics into the tool’s design,applying the microscopic structure of the biological surface to the tool surface to alleviate the tool’s failure.This paper mainly summarizes the research progress of bionic textured cutting tools.Firstly,categorize whether the bionic texture design is inspired by a single organism or multiple organisms.Secondly,it is discussed that the non-smooth surface of the biological surface has five characteristics:hydrophilic lubricity,wear resistance,drag reduction and hydrophobicity,anti-adhesion,and arrangement,and the non-smooth structure of these different characteristics are applied to the surface of the tool is designed with bionic texture.Furtherly,the cutting performance of bionic textured cutting tools is discussed.The anti-friction and wear-resisting mechanism of bionic textured cutting tools is analyzed.Finally,some pending problems and perspectives have been proposed to provide new inspirations for the design of bionic textured cutting tools.展开更多
The effects of trace yttrium(Y)element on the microstructure,mechanical properties,and corrosion resistance of Mg-2Zn-0.1Mn-0.3Ca-xY(x=0,0.1,0.2,0.3)biological magnesium alloys are investigated.Results show that grain...The effects of trace yttrium(Y)element on the microstructure,mechanical properties,and corrosion resistance of Mg-2Zn-0.1Mn-0.3Ca-xY(x=0,0.1,0.2,0.3)biological magnesium alloys are investigated.Results show that grain size decreases from 310 to 144µm when Y content increases from 0wt%to 0.3wt%.At the same time,volume fraction of the second phase increases from 0.4%to 6.0%,yield strength of the alloy continues to increase,and ultimate tensile strength and elongation decrease initially and then increase.When the Y content increases to 0.3wt%,Mg_(3)Zn_(6)Y phase begins to precipitate in the alloy;thus,the alloy exhibits the most excellent mechanical property.At this time,its ultimate tensile strength,yield strength,and elongation are 119 MPa,69 MPa,and 9.1%,respectively.In addition,when the Y content is 0.3wt%,the alloy shows the best corrosion resistance in the simulated body fluid(SBF).This investigation has revealed that the improvement of mechanical properties and corrosion resistance is mainly attributed to the grain refinement and the precipitated Mg_(3)Zn_(6)Y phase.展开更多
Honeybees have received public attention for their remarkable performance in low-altitude flying and their outstanding airborne hovering capability. However, minimal attention has been given to their capability to fly...Honeybees have received public attention for their remarkable performance in low-altitude flying and their outstanding airborne hovering capability. However, minimal attention has been given to their capability to fly through the harshest climatic conditions. In this study, we used a high-speed camera and recorded an interesting phenomenon in which honeybees （Apis mellifera ligustica） flew effortlessly through mists or drizzling rain. To identify the mechanism behind honeybees flying through mists, the microstructure of their wings was examined via atomic force microscopy and scanning electron microscopy. Ex- perimental results showed that the surface of a honeybee wing was rough, with bristles distributed on both the dorsal and ventral sides. The measurement results of the contact angle proved that the surface of honeybee wings was hydrophobie. Furthermore, hydrophobic proteins, which contained at least one hydrophobic tetra-peptide （i.e., AAPA/V）, were obtained. The rugged sur- face and hydrophobic proteins caused the hydrophobicity of honeybee wings. These results identify the hydrophobic mechanism of honeybee wings, which will be useful in designing hydrophobic structures.展开更多
Background With aging, the human fracture risk gradually increase. This is mainly due to the corresponding changes of the biomechanical parameters of human bone presents with aging. We measured the microstructural par...Background With aging, the human fracture risk gradually increase. This is mainly due to the corresponding changes of the biomechanical parameters of human bone presents with aging. We measured the microstructural parameters of lumbar bone from women in several age groups by micro-computed tomography and scanning electron microscopy. We observed changes in lumbar cancellous bone mineral density and in biomechanical parameters with aging to elucidate the relationship between age and risk of fracture. We provide theoretical support for human pathology, fracture risk increased with age and the individualized of each age group.展开更多
本研究以大豆分离蛋白(SPI)作为乳化剂和稳定剂,吸附在油水界面,形成O/W(水包油)型乳液(蛋白浓度2.0 wt%,大豆油浓度20.0 wt%),在人工胃液的模型中(37℃,p H 1.2,34 m M Na Cl离子强度,95 r/min持续摇动2 h),检测乳液的粒径,Zeta电位和...本研究以大豆分离蛋白(SPI)作为乳化剂和稳定剂,吸附在油水界面,形成O/W(水包油)型乳液(蛋白浓度2.0 wt%,大豆油浓度20.0 wt%),在人工胃液的模型中(37℃,p H 1.2,34 m M Na Cl离子强度,95 r/min持续摇动2 h),检测乳液的粒径,Zeta电位和显微结构。通过检测乳液的显微结构和粒径表明,大豆分离蛋白(p H 7.0)能够形成稳定的乳液,但在人工胃液的模型中,乳液液滴会出现絮凝或结合现象。并且,液滴絮凝或结合程度取决于水解时间。乳液的Zeta电位检测结果表明,SPI乳液与人工胃液混合后,乳液的Zeta电位由﹣35.9±0.3 m V变化到﹢16.3±0.9 m V。对未经乳化的SPI溶液和乳化后的乳液进行SDS-PAGE分析表明,吸附到油水界面的SPI蛋白更容易被胃蛋白酶水解。本研究能够提高人们对O/W型SPI乳液基于人工胃液模型下降解特性的认识,对设计以SPI乳液为基础的食品系统具有重要的指导意义。展开更多
基金supported by National Natural Science Foundation of China(52175431)Natural Science Foundation of Tianjin of China(22JCZDJC00730).
文摘Cutting tools are known as the“productivity”of the manufacturing industry,which affects the production efficiency and quality of the workpiece,and has become the focus of research and attention in academia and industry.However,traditional cutting tools often suffer from adhesion or wear during the cutting process,which considerably reduces the cutting efficiency and service life of the tools,and makes it difficult to meet current production requirements.To solve the above problems,scholars have introduced bionics into the tool’s design,applying the microscopic structure of the biological surface to the tool surface to alleviate the tool’s failure.This paper mainly summarizes the research progress of bionic textured cutting tools.Firstly,categorize whether the bionic texture design is inspired by a single organism or multiple organisms.Secondly,it is discussed that the non-smooth surface of the biological surface has five characteristics:hydrophilic lubricity,wear resistance,drag reduction and hydrophobicity,anti-adhesion,and arrangement,and the non-smooth structure of these different characteristics are applied to the surface of the tool is designed with bionic texture.Furtherly,the cutting performance of bionic textured cutting tools is discussed.The anti-friction and wear-resisting mechanism of bionic textured cutting tools is analyzed.Finally,some pending problems and perspectives have been proposed to provide new inspirations for the design of bionic textured cutting tools.
基金financially supported by the National Natural Science Foundation of China(Nos.52005034 and 52027805)the China Postdoctoral Science Foundation Funded Project(No.2021M691860)+2 种基金the Beijing Postdoctoral Research Foundation(No.2021-ZZ-073)the Zhuhai Industry-University-Research Cooperation Project(No.ZH22017001200176PWC)the Tai’an City Science and Technology Innovation Major Project(No.2021ZDZX011)。
文摘The effects of trace yttrium(Y)element on the microstructure,mechanical properties,and corrosion resistance of Mg-2Zn-0.1Mn-0.3Ca-xY(x=0,0.1,0.2,0.3)biological magnesium alloys are investigated.Results show that grain size decreases from 310 to 144µm when Y content increases from 0wt%to 0.3wt%.At the same time,volume fraction of the second phase increases from 0.4%to 6.0%,yield strength of the alloy continues to increase,and ultimate tensile strength and elongation decrease initially and then increase.When the Y content increases to 0.3wt%,Mg_(3)Zn_(6)Y phase begins to precipitate in the alloy;thus,the alloy exhibits the most excellent mechanical property.At this time,its ultimate tensile strength,yield strength,and elongation are 119 MPa,69 MPa,and 9.1%,respectively.In addition,when the Y content is 0.3wt%,the alloy shows the best corrosion resistance in the simulated body fluid(SBF).This investigation has revealed that the improvement of mechanical properties and corrosion resistance is mainly attributed to the grain refinement and the precipitated Mg_(3)Zn_(6)Y phase.
文摘Honeybees have received public attention for their remarkable performance in low-altitude flying and their outstanding airborne hovering capability. However, minimal attention has been given to their capability to fly through the harshest climatic conditions. In this study, we used a high-speed camera and recorded an interesting phenomenon in which honeybees （Apis mellifera ligustica） flew effortlessly through mists or drizzling rain. To identify the mechanism behind honeybees flying through mists, the microstructure of their wings was examined via atomic force microscopy and scanning electron microscopy. Ex- perimental results showed that the surface of a honeybee wing was rough, with bristles distributed on both the dorsal and ventral sides. The measurement results of the contact angle proved that the surface of honeybee wings was hydrophobie. Furthermore, hydrophobic proteins, which contained at least one hydrophobic tetra-peptide （i.e., AAPA/V）, were obtained. The rugged sur- face and hydrophobic proteins caused the hydrophobicity of honeybee wings. These results identify the hydrophobic mechanism of honeybee wings, which will be useful in designing hydrophobic structures.
文摘Background With aging, the human fracture risk gradually increase. This is mainly due to the corresponding changes of the biomechanical parameters of human bone presents with aging. We measured the microstructural parameters of lumbar bone from women in several age groups by micro-computed tomography and scanning electron microscopy. We observed changes in lumbar cancellous bone mineral density and in biomechanical parameters with aging to elucidate the relationship between age and risk of fracture. We provide theoretical support for human pathology, fracture risk increased with age and the individualized of each age group.
文摘本研究以大豆分离蛋白(SPI)作为乳化剂和稳定剂,吸附在油水界面,形成O/W(水包油)型乳液(蛋白浓度2.0 wt%,大豆油浓度20.0 wt%),在人工胃液的模型中(37℃,p H 1.2,34 m M Na Cl离子强度,95 r/min持续摇动2 h),检测乳液的粒径,Zeta电位和显微结构。通过检测乳液的显微结构和粒径表明,大豆分离蛋白(p H 7.0)能够形成稳定的乳液,但在人工胃液的模型中,乳液液滴会出现絮凝或结合现象。并且,液滴絮凝或结合程度取决于水解时间。乳液的Zeta电位检测结果表明,SPI乳液与人工胃液混合后,乳液的Zeta电位由﹣35.9±0.3 m V变化到﹢16.3±0.9 m V。对未经乳化的SPI溶液和乳化后的乳液进行SDS-PAGE分析表明,吸附到油水界面的SPI蛋白更容易被胃蛋白酶水解。本研究能够提高人们对O/W型SPI乳液基于人工胃液模型下降解特性的认识,对设计以SPI乳液为基础的食品系统具有重要的指导意义。
