Based on the theories of finite deformation elasticity, electromechanical responses and instability of an incompressible electro-active polymer （EAP） cylindrical shell, which is subjected to an internal pressure and...Based on the theories of finite deformation elasticity, electromechanical responses and instability of an incompressible electro-active polymer （EAP） cylindrical shell, which is subjected to an internal pressure and a static electric field, are studied. Deformation curves and distribution of stresses are obtained. It is found that an internal pressure together with an electric field may cause the unstable non-monotonic deforma- tion of the shell. It is also shown that a critical thickness for the shell exists, and the shell may undergo the unstable deformation if its thickness is less than this critical value. In addition, the effects of the electric field, axial stretch, thickness, and internal pressure on the instability of the shell are discussed.展开更多
A single-Rh-site catalyst(Rh-TPISP)that was ionically-embedded on a P(V)quaternary phosphonium porous polymer was evaluated for heterogeneous ethanol carbonylation.The[Rh(CO)I_(3)]^(2-)unit was proposed to be the acti...A single-Rh-site catalyst(Rh-TPISP)that was ionically-embedded on a P(V)quaternary phosphonium porous polymer was evaluated for heterogeneous ethanol carbonylation.The[Rh(CO)I_(3)]^(2-)unit was proposed to be the active center of Rh-TPISP for the carbonylation reaction based on detailed Rh L3-edge X-ray absorption near edge structure(XANES),X-ray photoelectron spectroscopy(XPS),and Rh extended X-ray absorption fine structure(EXAFS)analyses.As the highlight of this study,Rh-TPISP displayed distinctly higher activity for heterogeneous ethanol carbonylation than the reported catalytic systems in which[Rh(CO)_(2)I_(2)]^(-)is the traditional active center.A TOF of 350 h^(-1)was obtained for the reaction over[Rh(CO)I_(3)]^(2-),with>95%propionyl selectivity at 3.5 MPa and 468 K.No deactivation was detected during a near 1000 h running test.The more electron-rich Rh center was thought to be crucial for explaining the superior activity and selectivity of Rh-TPISP,and the formation of two ionic bonds between[Rh(CO)I_(3)]^(2-)and the cationic P(V)framework([P]^(+))of the polymer was suggested to play a key role in firmly immobilizing the active species to prevent Rh leaching.展开更多
An advanced electro-active dry adhesive, which was composed of a mushroom-shaped tibrillar dry adhesive array actuated by an Ionic Polymer Metal Composite （IPMC） artificial muscle reinforced with nitrogen-doped carb...An advanced electro-active dry adhesive, which was composed of a mushroom-shaped tibrillar dry adhesive array actuated by an Ionic Polymer Metal Composite （IPMC） artificial muscle reinforced with nitrogen-doped carbon nanocages （NCNCs）, was developed to imitate the actuation of a gecko＇s toe. The properties of the NCNC-reinforced Nation membrane, the electro- mechanical properties of the NCNC-reinforced IPMC, and the related electro-active adhesion ability were investigated. The NCNCs were uniformly dispersed in the 0.1 wt% NCNC/Nafion membrane, and there was a seamless connection with no clear interface between the dry adhesive and the IPMC. Our 0.1 wt% NCNC/Nation-IPMC actuator shows a displacement and force that are 1.6 - 2 times higher than those of the recast Nafion-IPMC. This is due to the increased water uptake （25.39%） and tensile strength （24.5 MPa） of the specific 3D hollow NCNC-reinforced Nation membrane, as well as interactions between the NCNCs and the sulfonated groups of the Nation. The NCNC/Nation-IPMC was used to effectively actuate the mushroom-shaped dry adhesive. The normal adhesion forces were 7.85 raN, 12.1 mN, and 51.7 mN at sinusoidal voltages of 1.5 V, 2.5 V, and 3.5 V, respectively, at 0.1 Hz. Under the bionic leg trail, the normal and shear forces were approximately 713.5 mN （159 mN·cm^-2） and 1256.6 mN （279 mN·cm^-2）, respectively, which satisfy the required adhesion. This new electro-active dry adhesive can be applied for active, distributed actuation and flexible grip in robots.展开更多
Two new one-dimensional chains extended by alternate benzenedicarboxylate（BDC） and 4-（2,6-di（pyrazin-2-yl）pyridin-4-yl）benzoate（L-） connectors, {[Cu（L）（BDC）（0.5）]·3.5 H2 O}n （1） and {[Zn（L）（BD...Two new one-dimensional chains extended by alternate benzenedicarboxylate（BDC） and 4-（2,6-di（pyrazin-2-yl）pyridin-4-yl）benzoate（L-） connectors, {[Cu（L）（BDC）（0.5）]·3.5 H2 O}n （1） and {[Zn（L）（BDC）（0.5）] ·H2 O}n （2）, were solvothermally synthesized. Complex 1 is in triclinic system, space group P1 with a = 9.6456（14）, b = 11.1160（16）, c = 12.0414（18） A, α = 106.266（3）, β = 92.277（3）, γ =108.104（3）°, V = 1166.6（3） A3, Dc = 1.603 g·cm（-3）, Mr = 563.00, Z = 2, F（000） = 578, μ = 0.996 mm（-1）, the final R = 0.0575 and wR = 0.1386 for 3704 observed reflections with I ＆gt; 2σ（I）. Complex 2 crystallizes in monoclinic, space group C2/c with a = 28.607（5）, b = 8.9767（16）, c = 19.705（4） ？, β = 125.396（3）°, V = 4125.0（13） ？3, Dc = 1.674 g·cm（-3）, Mr = 519.79, Z = 8, F（000） = 2120, μ = 1.242 mm（-1）, the final R = 0.0487 and w R = 0.0907 for 2944 observed reflections with I ＆gt; 2σ（I）. Resulting from the narrower band gap and broader response to visible light, the CuII-chain exhibits better photocatalytic performance towards the degradation of rhodamine B and methylene blue than those of ZnII-chain.展开更多
文章针对离子聚合物-金属复合材料(ionic polymer metal composite,IPMC)的松弛效应,将模糊控制与PID控制相结合设计了模糊PID控制器,实现了其PID的参数自整定功能;采用Matlab/Simulink分别对模糊PID控制系统和常规PID控制系统进行仿真...文章针对离子聚合物-金属复合材料(ionic polymer metal composite,IPMC)的松弛效应,将模糊控制与PID控制相结合设计了模糊PID控制器,实现了其PID的参数自整定功能;采用Matlab/Simulink分别对模糊PID控制系统和常规PID控制系统进行仿真,仿真结果表明,模糊PID控制系统响应时间为0.2 s,远小于常规PID控制系统的1.5 s,模糊PID控制系统的最大超调量比常规PID控制系统降低了74.5%,稳态误差降低了65.6%;采用STC51单片机对模糊PID控制系统和常规PID控制系统进行了IPMC末端输出位移控制实验,结果表明模糊PID控制系统的最大超调量比常规PID控制系统降低了77%,稳态误差降低了49%。该文设计的模糊PID控制系统对IPMC末端输出位移的控制效果比常规PID控制系统有了显著改进,对IPMC材料的应用具有较为重要的促进作用。展开更多
基金Project supported by the National Natural Science Foundation of China(No.10772104)the Shanghai Leading Academic Discipline Project(No.S30106)
文摘Based on the theories of finite deformation elasticity, electromechanical responses and instability of an incompressible electro-active polymer （EAP） cylindrical shell, which is subjected to an internal pressure and a static electric field, are studied. Deformation curves and distribution of stresses are obtained. It is found that an internal pressure together with an electric field may cause the unstable non-monotonic deforma- tion of the shell. It is also shown that a critical thickness for the shell exists, and the shell may undergo the unstable deformation if its thickness is less than this critical value. In addition, the effects of the electric field, axial stretch, thickness, and internal pressure on the instability of the shell are discussed.
文摘A single-Rh-site catalyst(Rh-TPISP)that was ionically-embedded on a P(V)quaternary phosphonium porous polymer was evaluated for heterogeneous ethanol carbonylation.The[Rh(CO)I_(3)]^(2-)unit was proposed to be the active center of Rh-TPISP for the carbonylation reaction based on detailed Rh L3-edge X-ray absorption near edge structure(XANES),X-ray photoelectron spectroscopy(XPS),and Rh extended X-ray absorption fine structure(EXAFS)analyses.As the highlight of this study,Rh-TPISP displayed distinctly higher activity for heterogeneous ethanol carbonylation than the reported catalytic systems in which[Rh(CO)_(2)I_(2)]^(-)is the traditional active center.A TOF of 350 h^(-1)was obtained for the reaction over[Rh(CO)I_(3)]^(2-),with>95%propionyl selectivity at 3.5 MPa and 468 K.No deactivation was detected during a near 1000 h running test.The more electron-rich Rh center was thought to be crucial for explaining the superior activity and selectivity of Rh-TPISP,and the formation of two ionic bonds between[Rh(CO)I_(3)]^(2-)and the cationic P(V)framework([P]^(+))of the polymer was suggested to play a key role in firmly immobilizing the active species to prevent Rh leaching.
基金This work was partially supported by the National Natural Science Foundation of China （Grant Nos. 51605220, U1637101, 51435008）, the Natural Science Foundation of Jiangsu Province （Grant No. BK20160793）, the High Level Introduction of Talent Research Start-up Fund in NUAA （Grant No. 1011-YAH16010）, and Open Project Fund in Jiangsu Provincial Key Laboratory for Interventional Medical Devices （Grant No. jr1601）. The authors would very much like to thank Professor Stanislav N. Gorb in the Department of Functional Morphology and Biome- chanics in the Zoological Institute of the University of Kiel, Germany, for his help with the mushroom-shapeddry adhesives, and also thank Dr. Yajun Xue and Miss Yan Ding for help with the SEM observations.
文摘An advanced electro-active dry adhesive, which was composed of a mushroom-shaped tibrillar dry adhesive array actuated by an Ionic Polymer Metal Composite （IPMC） artificial muscle reinforced with nitrogen-doped carbon nanocages （NCNCs）, was developed to imitate the actuation of a gecko＇s toe. The properties of the NCNC-reinforced Nation membrane, the electro- mechanical properties of the NCNC-reinforced IPMC, and the related electro-active adhesion ability were investigated. The NCNCs were uniformly dispersed in the 0.1 wt% NCNC/Nafion membrane, and there was a seamless connection with no clear interface between the dry adhesive and the IPMC. Our 0.1 wt% NCNC/Nation-IPMC actuator shows a displacement and force that are 1.6 - 2 times higher than those of the recast Nafion-IPMC. This is due to the increased water uptake （25.39%） and tensile strength （24.5 MPa） of the specific 3D hollow NCNC-reinforced Nation membrane, as well as interactions between the NCNCs and the sulfonated groups of the Nation. The NCNC/Nation-IPMC was used to effectively actuate the mushroom-shaped dry adhesive. The normal adhesion forces were 7.85 raN, 12.1 mN, and 51.7 mN at sinusoidal voltages of 1.5 V, 2.5 V, and 3.5 V, respectively, at 0.1 Hz. Under the bionic leg trail, the normal and shear forces were approximately 713.5 mN （159 mN·cm^-2） and 1256.6 mN （279 mN·cm^-2）, respectively, which satisfy the required adhesion. This new electro-active dry adhesive can be applied for active, distributed actuation and flexible grip in robots.
文摘Two new one-dimensional chains extended by alternate benzenedicarboxylate（BDC） and 4-（2,6-di（pyrazin-2-yl）pyridin-4-yl）benzoate（L-） connectors, {[Cu（L）（BDC）（0.5）]·3.5 H2 O}n （1） and {[Zn（L）（BDC）（0.5）] ·H2 O}n （2）, were solvothermally synthesized. Complex 1 is in triclinic system, space group P1 with a = 9.6456（14）, b = 11.1160（16）, c = 12.0414（18） A, α = 106.266（3）, β = 92.277（3）, γ =108.104（3）°, V = 1166.6（3） A3, Dc = 1.603 g·cm（-3）, Mr = 563.00, Z = 2, F（000） = 578, μ = 0.996 mm（-1）, the final R = 0.0575 and wR = 0.1386 for 3704 observed reflections with I ＆gt; 2σ（I）. Complex 2 crystallizes in monoclinic, space group C2/c with a = 28.607（5）, b = 8.9767（16）, c = 19.705（4） ？, β = 125.396（3）°, V = 4125.0（13） ？3, Dc = 1.674 g·cm（-3）, Mr = 519.79, Z = 8, F（000） = 2120, μ = 1.242 mm（-1）, the final R = 0.0487 and w R = 0.0907 for 2944 observed reflections with I ＆gt; 2σ（I）. Resulting from the narrower band gap and broader response to visible light, the CuII-chain exhibits better photocatalytic performance towards the degradation of rhodamine B and methylene blue than those of ZnII-chain.
