African ostrich can run for 30 min at a speed of 60 km/h in the desert,and its hindlimb has excellent energy saving and vibration damping performance.In order to realize the energy⁃efficient and vibration⁃damping desi...African ostrich can run for 30 min at a speed of 60 km/h in the desert,and its hindlimb has excellent energy saving and vibration damping performance.In order to realize the energy⁃efficient and vibration⁃damping design of the leg mechanism of the legged robot,the principle of engineering bionics was applied.According to the passive rebound characteristic of the intertarsal joint of the ostrich foot and the characteristic of variable output stiffness of the ostrich hindlimb,combined with the proportion and size of the structure of the ostrich hindlimb,the bionic rigid⁃flexible composite legged robot single⁃leg structure was designed.The locomotion of the bionic mechanical leg was simulated by means of ADAMS.Through the motion simulation analysis,the influence of the change of the inner spring stiffness coefficient within a certain range on the vertical acceleration of the body centroid and the motor power consumption was studied,and the optimal stiffness coefficient of the inner spring was obtained to be 200 N/mm,and it was further verified that the inner and outer spring mechanism could effectively reduce the energy consumption of the mechanical leg.Simulation results show that the inner and outer spring mechanism could effectively reduce the motor energy consumption by about 72.49%.展开更多
[Objectives]To explore the effect and possible mechanism of bergenin in relieving allergic rhinitis(AR)in mice.[Methods]50 C57/BL6 mice were randomly divided into blank group(n=10),model group(n=10)and high(100 mg/kg)...[Objectives]To explore the effect and possible mechanism of bergenin in relieving allergic rhinitis(AR)in mice.[Methods]50 C57/BL6 mice were randomly divided into blank group(n=10),model group(n=10)and high(100 mg/kg),medium(50 mg/kg)and low(25 mg/kg)dose bergenin groups with 10 mice in each group.Except for the blank group,the other mice were sensitized by basic ways combined with attack to replicate the AR model.From the 15th d of modeling(from the second d after the end of the basic modeling),the drug group was given bergenin orally for 15 d,and the blank group and model group were given the same volume of normal saline once a day.24 h after the last establishment of the model,the content of interleukin 4(IL-4),IL-6,TNF-αand IL-1βin nasal lavage fluid and serum of mice in each group was detected by ELISA.The expression of TLR-4,NF-κB and p-NF-κB in nasal mucosa of mice was detected by Western blot.[Results]Compared with the blank group,the content of inflammatory factors IL-4,IL-6,TNF-αand IL-1βin nasal lavage fluid and serum of model group was significantly increased,and the protein expression of TLR-4 and p-NF-κB was significantly increased.After the intervention of bergenin,the content of IL-4,IL-6,TNF-αand IL-1βin nasal lavage fluid and serum and TLR-4 and p-NF-κB protein in tissue was significantly inhibited in bergenin group.[Conclusions]Bergenin can effectively reduce allergic inflammation in AR model mice,and its mechanism may be related to inhibition of inflammation and down-regulation of TLR-4/NF-κB signal pathway.展开更多
Aromatic carboxylic acid self-assembly has been a hot research field for many scientists due to its strong coordination ability and flexible coordination mode.The hydrogen bond formed between aromatic carboxylic acids...Aromatic carboxylic acid self-assembly has been a hot research field for many scientists due to its strong coordination ability and flexible coordination mode.The hydrogen bond formed between aromatic carboxylic acids is a strong intermolecular force and has directionality and saturation,which plays a very important role in the self-assembly and regulation of aromatic carboxylic acids.In this review,we introduce surface organization formed by aromatic carboxylic acids with the aid of scanning tunneling microscopy(STM).These two-dimensional structures include molecular templates,host-guest systems,and photo-isomerization structures.We also emphasize the thermodynamics and dynamics,which are important research topics of current and future study.展开更多
Here,the selective adsorption behaviors of guest molecule COR in two hexamer host grids were investigated by means of scanning tunnelling microscope(STM).The assembled structures of small functional organic molecules ...Here,the selective adsorption behaviors of guest molecule COR in two hexamer host grids were investigated by means of scanning tunnelling microscope(STM).The assembled structures of small functional organic molecules TTBTA and TATBA were thermodynamically stable.Interestingly,the introduction of the guest molecule COR destroyed the original hexamer structure of TTBTA and combined with it to form a new triangular host-guest system.Different from TTBTA,the introduction of the guest molecule COR did not affect the six-membered ring structure of TATBA.Furthermore,the co-assembly structure of TTBTA/TATBA/COR was established and the guest molecule COR showed preferential adsorption to the TATBA host grid.Density functional theory(DFT)calculations had been performed to disclose the mechanism of the involved assemblies.展开更多
The self-assembled behavior of an unsymmetric molecule(BCDTDA)with one imidazole group as center and benzoic acid group as functional group is studied,and the regulatory behaviors of coronene(COR)and three bipyridine ...The self-assembled behavior of an unsymmetric molecule(BCDTDA)with one imidazole group as center and benzoic acid group as functional group is studied,and the regulatory behaviors of coronene(COR)and three bipyridine derivatives(named BP,PEBP-C4 and PEBP-C8)on BCDTDA self-assembly structures are also investigated.Based on highly oriented pyrolytic graphite(HOPG)substrate,scanning tunneling microscopy(STM)is used to observe the variation of assembled behaviors at the solid-liquid interface.Because of the concentration effect,BCDTDA molecules can assemble into grids and Kagomés structures in the form of N–H…O hydrogen bonded dimers.BCDTDA molecules still maintain dimeric structures in the regulation of COR and BP molecules to BCDTDA self-assembly.However,PEBP-C4 and PEBP-C8 destroy the structure of the dimers,and form a variety of co-assembled structures with BCDTDA.Different guest molecules coordinate the host molecules differently,which makes the experiment more meaningful.Combined with density functional theory(DFT)calculation,the discovery of molecular interactions provides a promising strategy for the construction of functional nanostructures and devices.展开更多
The prediction of two-dimensional molecular self-assembly structures has always been a problem to be solved.The molecules with meta-dicarboxyl groups can self-assemble into a specific hexagonal cavity,which has an imp...The prediction of two-dimensional molecular self-assembly structures has always been a problem to be solved.The molecules with meta-dicarboxyl groups can self-assemble into a specific hexagonal cavity,which has an important influence on the prediction of molecular self-assembly structures and the application of functional molecules with meta-dicarboxyl groups.Two kinds of molecules with four pairs of meta-dicarboxyl groups,1,3,6,8-tet「akis(3,5-isophthalic acid)pyrene(H_(8)TIAPy)and 4′,4′",4′"",4""-(ethene-1,1,2,2-tetrayl)tetrakis(([1,1′-biphenyl]-3,5-dicarboxylic acid))(H8ETTB)molecules were chosen to observe the self-assembly behavior at the heptanoic acid/highly oriented pyrolytic graphite(HA/HOPG)interface.H8TIAPy molecules self-assembled into well-ordered quadrilateral structures and could be regulated into kagome networks with hexagonal pores by coronene(COR)molecules.H8ETTB molecules self-assembled into lamellar structures and transformed into acid-COR-acid-COR co-assembled structures at low concentration of COR solution and acid-COR dimer-acid-COR dimer co-assembled structures at high concentration of COR solution.The reason that H8ETTB molecules could not be regulated into hexagonal porous architecture was attributed to the steric hindrance by the similar length and width of H8ETTB molecules.The H8ETTB templates had stronger adsorption for COR than that of hexaphenylbenzene(HPB),regardless of the order of molecular introduction.展开更多
Host-guest chemistry in two-dimensional (2D) networks has gained much interest for the new functionalities and potential applications, such as separation technology, photogenic crystals and biomimetic surfaces. Nanopo...Host-guest chemistry in two-dimensional (2D) networks has gained much interest for the new functionalities and potential applications, such as separation technology, photogenic crystals and biomimetic surfaces. Nanoporous supramolecular networks are assembled by a range of non-covalent forces like hydrogen bonds, van der Waals interactions and coordinate bonds, to immobilize guest molecules of different sizes and shapes. In this review, we mainly presented the effect of coronene on the host-guest architecture. Coronene (COR) is chosen to be the promising guest molecule and it can embed, cover, or change the host networks in different host-guest systems. All of the research in the review was finished with assistance of scanning tunneling microscope (STM). These studies were called upon impose controlling on host-guest systems and revealed the behaviors of COR clusters as guest molecules.展开更多
Based on observing and analyzing the typical soil animals, the flexible unsmoothness is defined, which is the moving unsmoothness made by the flexible deformation of the structural units, and its characteristics of re...Based on observing and analyzing the typical soil animals, the flexible unsmoothness is defined, which is the moving unsmoothness made by the flexible deformation of the structural units, and its characteristics of reducing adhesion and resistance is analyzed. The tests show that on the same conditions, compared with 45 Steel, the adhesion of the field_mouse’s fur is reduced by about 35%, its sliding resistance is reduced by about 80%.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant Nos.51675221 and 91748211)the Science and Technology Development Planning Project of Jilin Province of China(Grant No.20180101077JC)the Science and Technology Research Project in the 13th Five⁃Year Period of Education Department of Jilin Province(Grant No.JJKH20190134KJ).
文摘African ostrich can run for 30 min at a speed of 60 km/h in the desert,and its hindlimb has excellent energy saving and vibration damping performance.In order to realize the energy⁃efficient and vibration⁃damping design of the leg mechanism of the legged robot,the principle of engineering bionics was applied.According to the passive rebound characteristic of the intertarsal joint of the ostrich foot and the characteristic of variable output stiffness of the ostrich hindlimb,combined with the proportion and size of the structure of the ostrich hindlimb,the bionic rigid⁃flexible composite legged robot single⁃leg structure was designed.The locomotion of the bionic mechanical leg was simulated by means of ADAMS.Through the motion simulation analysis,the influence of the change of the inner spring stiffness coefficient within a certain range on the vertical acceleration of the body centroid and the motor power consumption was studied,and the optimal stiffness coefficient of the inner spring was obtained to be 200 N/mm,and it was further verified that the inner and outer spring mechanism could effectively reduce the energy consumption of the mechanical leg.Simulation results show that the inner and outer spring mechanism could effectively reduce the motor energy consumption by about 72.49%.
文摘[Objectives]To explore the effect and possible mechanism of bergenin in relieving allergic rhinitis(AR)in mice.[Methods]50 C57/BL6 mice were randomly divided into blank group(n=10),model group(n=10)and high(100 mg/kg),medium(50 mg/kg)and low(25 mg/kg)dose bergenin groups with 10 mice in each group.Except for the blank group,the other mice were sensitized by basic ways combined with attack to replicate the AR model.From the 15th d of modeling(from the second d after the end of the basic modeling),the drug group was given bergenin orally for 15 d,and the blank group and model group were given the same volume of normal saline once a day.24 h after the last establishment of the model,the content of interleukin 4(IL-4),IL-6,TNF-αand IL-1βin nasal lavage fluid and serum of mice in each group was detected by ELISA.The expression of TLR-4,NF-κB and p-NF-κB in nasal mucosa of mice was detected by Western blot.[Results]Compared with the blank group,the content of inflammatory factors IL-4,IL-6,TNF-αand IL-1βin nasal lavage fluid and serum of model group was significantly increased,and the protein expression of TLR-4 and p-NF-κB was significantly increased.After the intervention of bergenin,the content of IL-4,IL-6,TNF-αand IL-1βin nasal lavage fluid and serum and TLR-4 and p-NF-κB protein in tissue was significantly inhibited in bergenin group.[Conclusions]Bergenin can effectively reduce allergic inflammation in AR model mice,and its mechanism may be related to inhibition of inflammation and down-regulation of TLR-4/NF-κB signal pathway.
基金supported by the National Basic Research Program of China (No. 2016YFA0200700)the National Natural Science Foundation of China (Nos. 21773041 and 21472029)
文摘Aromatic carboxylic acid self-assembly has been a hot research field for many scientists due to its strong coordination ability and flexible coordination mode.The hydrogen bond formed between aromatic carboxylic acids is a strong intermolecular force and has directionality and saturation,which plays a very important role in the self-assembly and regulation of aromatic carboxylic acids.In this review,we introduce surface organization formed by aromatic carboxylic acids with the aid of scanning tunneling microscopy(STM).These two-dimensional structures include molecular templates,host-guest systems,and photo-isomerization structures.We also emphasize the thermodynamics and dynamics,which are important research topics of current and future study.
基金supported by the National Basic Research Program of China(No.2016YFA0200700)the National Natural Science Foundation of China(Nos.21773041 and 21972031)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB36000000)。
文摘Here,the selective adsorption behaviors of guest molecule COR in two hexamer host grids were investigated by means of scanning tunnelling microscope(STM).The assembled structures of small functional organic molecules TTBTA and TATBA were thermodynamically stable.Interestingly,the introduction of the guest molecule COR destroyed the original hexamer structure of TTBTA and combined with it to form a new triangular host-guest system.Different from TTBTA,the introduction of the guest molecule COR did not affect the six-membered ring structure of TATBA.Furthermore,the co-assembly structure of TTBTA/TATBA/COR was established and the guest molecule COR showed preferential adsorption to the TATBA host grid.Density functional theory(DFT)calculations had been performed to disclose the mechanism of the involved assemblies.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.21972031,12064026 and 22272039)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB36000000)Jilin Chinese Academy of Sciences-Yanshen Technology Co.,Ltd.
文摘The self-assembled behavior of an unsymmetric molecule(BCDTDA)with one imidazole group as center and benzoic acid group as functional group is studied,and the regulatory behaviors of coronene(COR)and three bipyridine derivatives(named BP,PEBP-C4 and PEBP-C8)on BCDTDA self-assembly structures are also investigated.Based on highly oriented pyrolytic graphite(HOPG)substrate,scanning tunneling microscopy(STM)is used to observe the variation of assembled behaviors at the solid-liquid interface.Because of the concentration effect,BCDTDA molecules can assemble into grids and Kagomés structures in the form of N–H…O hydrogen bonded dimers.BCDTDA molecules still maintain dimeric structures in the regulation of COR and BP molecules to BCDTDA self-assembly.However,PEBP-C4 and PEBP-C8 destroy the structure of the dimers,and form a variety of co-assembled structures with BCDTDA.Different guest molecules coordinate the host molecules differently,which makes the experiment more meaningful.Combined with density functional theory(DFT)calculation,the discovery of molecular interactions provides a promising strategy for the construction of functional nanostructures and devices.
基金supported by the National Natural Science Foundation of China(Nos.21773041,and 21972031)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB36000000)+1 种基金the Natural Science Foundation of Zhejiang Province(No.Y20B020032)China Scholarship Council(No.202007090155).
文摘The prediction of two-dimensional molecular self-assembly structures has always been a problem to be solved.The molecules with meta-dicarboxyl groups can self-assemble into a specific hexagonal cavity,which has an important influence on the prediction of molecular self-assembly structures and the application of functional molecules with meta-dicarboxyl groups.Two kinds of molecules with four pairs of meta-dicarboxyl groups,1,3,6,8-tet「akis(3,5-isophthalic acid)pyrene(H_(8)TIAPy)and 4′,4′",4′"",4""-(ethene-1,1,2,2-tetrayl)tetrakis(([1,1′-biphenyl]-3,5-dicarboxylic acid))(H8ETTB)molecules were chosen to observe the self-assembly behavior at the heptanoic acid/highly oriented pyrolytic graphite(HA/HOPG)interface.H8TIAPy molecules self-assembled into well-ordered quadrilateral structures and could be regulated into kagome networks with hexagonal pores by coronene(COR)molecules.H8ETTB molecules self-assembled into lamellar structures and transformed into acid-COR-acid-COR co-assembled structures at low concentration of COR solution and acid-COR dimer-acid-COR dimer co-assembled structures at high concentration of COR solution.The reason that H8ETTB molecules could not be regulated into hexagonal porous architecture was attributed to the steric hindrance by the similar length and width of H8ETTB molecules.The H8ETTB templates had stronger adsorption for COR than that of hexaphenylbenzene(HPB),regardless of the order of molecular introduction.
文摘Host-guest chemistry in two-dimensional (2D) networks has gained much interest for the new functionalities and potential applications, such as separation technology, photogenic crystals and biomimetic surfaces. Nanoporous supramolecular networks are assembled by a range of non-covalent forces like hydrogen bonds, van der Waals interactions and coordinate bonds, to immobilize guest molecules of different sizes and shapes. In this review, we mainly presented the effect of coronene on the host-guest architecture. Coronene (COR) is chosen to be the promising guest molecule and it can embed, cover, or change the host networks in different host-guest systems. All of the research in the review was finished with assistance of scanning tunneling microscope (STM). These studies were called upon impose controlling on host-guest systems and revealed the behaviors of COR clusters as guest molecules.
文摘Based on observing and analyzing the typical soil animals, the flexible unsmoothness is defined, which is the moving unsmoothness made by the flexible deformation of the structural units, and its characteristics of reducing adhesion and resistance is analyzed. The tests show that on the same conditions, compared with 45 Steel, the adhesion of the field_mouse’s fur is reduced by about 35%, its sliding resistance is reduced by about 80%.
