The contents of rutin,quercetin and kaempferol in powders of tartary buckwheat of different parts were determined by high-performance liquid chromatography( HPLC). The results showed that the contents of the three kin...The contents of rutin,quercetin and kaempferol in powders of tartary buckwheat of different parts were determined by high-performance liquid chromatography( HPLC). The results showed that the contents of the three kinds of flavonoids differed greatly in the powders of tartary buckwheat of different parts. The contents of rutin and quercetin in the powder of tartary buckwheat sprouts were significantly higher than those in the powders of tartary buckwheat leaves and seeds. The content of kaempferol was highest in the powder of tartary buckwheat seeds. It indicates that high-performance liquid chromatography can be used for quality control of tartary buckwheat powder for its time saving,cost saving and accurate and reliable results. The content of rutin in the powder of tartary buckwheat sprouts was highest,suggesting that it is more suitable for the development of various foods based on tartary buckwheat powder.展开更多
Silicon carbide fiber reinforced silicon carbide matrix(SiC_(f)/SiC)composite is the key cladding material of nuclear fuel,which determines the safety and reliability of nuclear fuel storage and transportation.The rep...Silicon carbide fiber reinforced silicon carbide matrix(SiC_(f)/SiC)composite is the key cladding material of nuclear fuel,which determines the safety and reliability of nuclear fuel storage and transportation.The replacement of its storage and transportation scenario needs to be completed by the manipulator,but the application of SiC_(f)/SiC wear,fracture,and nuclear leakage in the snatching process of brittle-flexible-rigid contact in the irradiation environment has been seriously restricted due to unclear understanding of the damage mechanism.Therefore,the effects of irradiation dose and clamping load on the friction characteristics of the contact interface between SiC_(f)/SiC clad tube are studied in this paper,and the effects of irradiation parameters and clamping force on the static friction coefficient of the contact interface between the clad tube and flexible nitrile are obtained.Based on the Greenwood-Williamson tribological model,a numerical model of the shape and structure of the contact micro-convex at the micro-scale of the clamping interface is constructed by introducing the multi-surface integral,and finally verified by experiments.The research results show that there is a unique“Irradiation suppression zone”under the clamping condition of SiC_(f)/SiC cladding tube under the nuclear irradiation environment,and the growth of static friction coefficient slows down until stagnates after irradiation reaches a certain extent(600 kGy),and there will be a decline when the irradiation dose continues to increase,among which the clamping force of 15.2 N within the irradiation interval of 1,000 kGy can meet the safety of nuclear environment operation.The results of this paper can provide an important theoretical basis and application guidance for the safe operation of SiC_(f)/SiC cladding tubes in the storage and transportation clamping process.展开更多
Liquid metals(LM) such as eutectic gallium-indium and gallium-indium-tin are important functional liquid-state metal materials with many unique properties, which have attracted wide attentions especially from soft rob...Liquid metals(LM) such as eutectic gallium-indium and gallium-indium-tin are important functional liquid-state metal materials with many unique properties, which have attracted wide attentions especially from soft robot area. Recently the amoeba-like transformations of LM on the graphite surface are discovered, which present a promising future for the design and assemble of self-fueled actuators with dendritically deformable body. It appears that the surface tension of the LM can be significantly reduced when it contacts graphite surface in alkaline solution. Clearly, the specific surface should play a vital role in inducing these intriguing behaviors, which is valuable and inspiring in soft robot design. However, the information regarding varied materials functions underlying these behaviors remains unknown. To explore the generalized effects of surface materials in those intriguing behavior, several materials including glass, graphite, nickel and copper oxides(CuO) were comparatively investigated as substrate surfaces.Important results were obtained that only LM amoeba transformations were observed on graphite and CuO surfaces. In order to identify the proper surface condition for LM transformation, the intrinsic properties of substrate surfaces, such as the surface charge and roughness, as well as the specific interaction with LM like wetting behavior and mutual locomotion etc., were characterized. The integrated results revealed that LM droplet appears more likely to deform on surfaces with higher positive surface charge density, higher roughness and less bubble generation on them. In addition, another surface material,CuOx, is identified to own similar ability to graphite, which is valuable in achieving amoeba-like transformation. Moreover, this study offers a fundamental understanding of the surface properties in realizing LM amoeba transformations, which would shed light on packing and structure design of liquid metal-based soft device within multi-material system.展开更多
Low-melting-temperature(LMT)metals and alloys based on post-transition metals,frequently dubbed as“liquid metals”,are enigmatic materials.Although they have been around for thousands of years,and we have continuousl...Low-melting-temperature(LMT)metals and alloys based on post-transition metals,frequently dubbed as“liquid metals”,are enigmatic materials.Although they have been around for thousands of years,and we have continuously been fascinated by what they are,our knowledge about them is still rudimentary.Perhaps the reason is that most electromagnetic waves or even electron beams can hardly penetrate through liquid metals and we tend to ignore what we cannot directly observe.展开更多
基金Supported by Key Science and Technology Project for Agriculture in Guizhou Province(NY[2013]3017)Project of Guizhou Tartary Buckwheat Engineering and Technology Research Center([2015]4003-B1)+2 种基金Doctoral Foundation of Science and Technology Plan of Guizhou Province([2017]1191)Youth Foundation of Guizhou Academy of Agricultural Sciences([2017]26)Key Technology Research and Development Program of Guizhou Province([2017]2543)
文摘The contents of rutin,quercetin and kaempferol in powders of tartary buckwheat of different parts were determined by high-performance liquid chromatography( HPLC). The results showed that the contents of the three kinds of flavonoids differed greatly in the powders of tartary buckwheat of different parts. The contents of rutin and quercetin in the powder of tartary buckwheat sprouts were significantly higher than those in the powders of tartary buckwheat leaves and seeds. The content of kaempferol was highest in the powder of tartary buckwheat seeds. It indicates that high-performance liquid chromatography can be used for quality control of tartary buckwheat powder for its time saving,cost saving and accurate and reliable results. The content of rutin in the powder of tartary buckwheat sprouts was highest,suggesting that it is more suitable for the development of various foods based on tartary buckwheat powder.
基金supported by the National Natural Science Foundation of China(Grant No.52075526)the“Ningbo 3315 Plan Innovation Team”(Grant No.2017A-28-C)+2 种基金the National Natural Science Foundation of China(Grant No.91860204)the Fundamental Research Funds for the Central Universities(Grant No.DUT22LAB605)the National Key R&D Program of China(Grant No.2018YFB1107500).
文摘Silicon carbide fiber reinforced silicon carbide matrix(SiC_(f)/SiC)composite is the key cladding material of nuclear fuel,which determines the safety and reliability of nuclear fuel storage and transportation.The replacement of its storage and transportation scenario needs to be completed by the manipulator,but the application of SiC_(f)/SiC wear,fracture,and nuclear leakage in the snatching process of brittle-flexible-rigid contact in the irradiation environment has been seriously restricted due to unclear understanding of the damage mechanism.Therefore,the effects of irradiation dose and clamping load on the friction characteristics of the contact interface between SiC_(f)/SiC clad tube are studied in this paper,and the effects of irradiation parameters and clamping force on the static friction coefficient of the contact interface between the clad tube and flexible nitrile are obtained.Based on the Greenwood-Williamson tribological model,a numerical model of the shape and structure of the contact micro-convex at the micro-scale of the clamping interface is constructed by introducing the multi-surface integral,and finally verified by experiments.The research results show that there is a unique“Irradiation suppression zone”under the clamping condition of SiC_(f)/SiC cladding tube under the nuclear irradiation environment,and the growth of static friction coefficient slows down until stagnates after irradiation reaches a certain extent(600 kGy),and there will be a decline when the irradiation dose continues to increase,among which the clamping force of 15.2 N within the irradiation interval of 1,000 kGy can meet the safety of nuclear environment operation.The results of this paper can provide an important theoretical basis and application guidance for the safe operation of SiC_(f)/SiC cladding tubes in the storage and transportation clamping process.
基金supported by the Dean’s Research Funding from the Chinese Academy of Sciences, Beijing Municipal Science and Technology Funding(Z151100003715002)the National Natural Science Foundation of China (61307065) and the National Key Research and Development Program of China (2016YFA0200500)
文摘Liquid metals(LM) such as eutectic gallium-indium and gallium-indium-tin are important functional liquid-state metal materials with many unique properties, which have attracted wide attentions especially from soft robot area. Recently the amoeba-like transformations of LM on the graphite surface are discovered, which present a promising future for the design and assemble of self-fueled actuators with dendritically deformable body. It appears that the surface tension of the LM can be significantly reduced when it contacts graphite surface in alkaline solution. Clearly, the specific surface should play a vital role in inducing these intriguing behaviors, which is valuable and inspiring in soft robot design. However, the information regarding varied materials functions underlying these behaviors remains unknown. To explore the generalized effects of surface materials in those intriguing behavior, several materials including glass, graphite, nickel and copper oxides(CuO) were comparatively investigated as substrate surfaces.Important results were obtained that only LM amoeba transformations were observed on graphite and CuO surfaces. In order to identify the proper surface condition for LM transformation, the intrinsic properties of substrate surfaces, such as the surface charge and roughness, as well as the specific interaction with LM like wetting behavior and mutual locomotion etc., were characterized. The integrated results revealed that LM droplet appears more likely to deform on surfaces with higher positive surface charge density, higher roughness and less bubble generation on them. In addition, another surface material,CuOx, is identified to own similar ability to graphite, which is valuable in achieving amoeba-like transformation. Moreover, this study offers a fundamental understanding of the surface properties in realizing LM amoeba transformations, which would shed light on packing and structure design of liquid metal-based soft device within multi-material system.
基金supported by the Australian Research Council(ARC)Laureate Fellowship grant(FL180100053)the ARC Centres of Excellence FLEET(CE170100039)M.A.R.acknowledges the ARC Discovery Early Career Researcher Award(DECRA)grant(DE210101162).
文摘Low-melting-temperature(LMT)metals and alloys based on post-transition metals,frequently dubbed as“liquid metals”,are enigmatic materials.Although they have been around for thousands of years,and we have continuously been fascinated by what they are,our knowledge about them is still rudimentary.Perhaps the reason is that most electromagnetic waves or even electron beams can hardly penetrate through liquid metals and we tend to ignore what we cannot directly observe.