Automatic navigation of an articulated drum roller, which is an articulated steering type vehicle widely used in the construction industry, is highly expected for operation cost reduction and improvement of work effi-...Automatic navigation of an articulated drum roller, which is an articulated steering type vehicle widely used in the construction industry, is highly expected for operation cost reduction and improvement of work effi- ciency. In order to achieve the path following control, considering that its steering system is articulated steering and two frames are articulated by an active revolute joint, a kinematic model and an error dynamic state-space equation of an articulated drum roller are proposed. Besides, a state- feedback control law based on Lyapunov stability theory is also designed, which can be proved to achieve the purpose of control by the analysis of stability. What＇s more, to evaluate the performance of the proposed method, simu- lation under the MATLAB/Simulink and experiments using positioning algorithm and errors correction at the uneven construction site are performed, with initial dis- placement error （-1.5 m）, heading error （-0.11 tad） and steering angle （-0.19 rad）. Finally, simulation and exper- imental results show that the errors and steering angle can decrease gradually, and converge to zero with time. Meanwhile, the control input is not saturated. An articu- lated drum roller can lock into a desired path with the proposed method in uneven fields.展开更多
To achieve targeted thrombolysis, a targeted delivery system of lumbrokinase(LK) was constructed using RGDfk-conjugated hybrid micelles. Based on the specific affinity of RGDfk to glycoprotein complex of GP Ⅱ b/Ⅲ a ...To achieve targeted thrombolysis, a targeted delivery system of lumbrokinase(LK) was constructed using RGDfk-conjugated hybrid micelles. Based on the specific affinity of RGDfk to glycoprotein complex of GP Ⅱ b/Ⅲ a expressed on the surface of membrane of activated platelet, LK loaded targeted micelles(LKTM) can be delivered to thrombus. The hybrid micelles were composed of polycaprolactone-block-poly(2-(dimethylamino) ethyl methacrylate)(PCL-PDMAEMA), methoxy polyethylene glycol-block-polycaprolactone(mPEG-PCL)and RGDfk conjugated polycaprolactone-block-polyethylene glycol(PCL-PEG-RGDfk). PCLPDMAEMA was synthesized via ring open polymerization(ROP) and atom transfer radical polymerization(ATRP). PCL-PEG-RGDfk was synthesized via ROP and carbodiimide chemistry. The prepared LKTM was characterized by dynamic light scattering(DLS) and transmission electron microscope(TEM). Colloidal stability assay showed the prepared LKTM was stable. Biocompatibility assay was performed to determine the safe concentration range of polymer. The assay of fluorescent distribution in vivo demonstrated that LKTM can be efficiently delivered to thrombi in vivo. Thrombolysis in vivo indicated the thrombolytic potency of LKTM was optimal in all groups. Notably, the laboratory mice treated with LKTM exhibited a significantly shorter tail bleeding time compared to those treated with LK or LK-loaded micelles without RGDfk, which suggested that the targeted delivery of LK using RGDfk-conjugated hybrid micelles effectively reduced the bleeding risk.展开更多
1.Introduction We are currently facing three major ecological threats on a global scale:biodiversity loss,climate change,and environmental pollution exacerbation.The degradation of terrestrial and marine ecosystems po...1.Introduction We are currently facing three major ecological threats on a global scale:biodiversity loss,climate change,and environmental pollution exacerbation.The degradation of terrestrial and marine ecosystems poses a major risk to human survival and development,brings serious impacts to the wellbeing of 3.2 billion people,and causes the loss of about 10%of the annual global gross domestic product(GDP)[1,2].Meanwhile,the coronavirus disease 2019(COVID-19)epidemic is still spreading rapidly throughout the world,showing that the present relationship between humans and nature is unsustainable.It is necessary to protect nature so as to maintain the self-resilience of ecosystems.展开更多
基金Supported by National Key Technology Support Program of China(Grant No.2015BAF07B05)Fundamental Research Funds for the Central Universities of China
文摘Automatic navigation of an articulated drum roller, which is an articulated steering type vehicle widely used in the construction industry, is highly expected for operation cost reduction and improvement of work effi- ciency. In order to achieve the path following control, considering that its steering system is articulated steering and two frames are articulated by an active revolute joint, a kinematic model and an error dynamic state-space equation of an articulated drum roller are proposed. Besides, a state- feedback control law based on Lyapunov stability theory is also designed, which can be proved to achieve the purpose of control by the analysis of stability. What＇s more, to evaluate the performance of the proposed method, simu- lation under the MATLAB/Simulink and experiments using positioning algorithm and errors correction at the uneven construction site are performed, with initial dis- placement error （-1.5 m）, heading error （-0.11 tad） and steering angle （-0.19 rad）. Finally, simulation and exper- imental results show that the errors and steering angle can decrease gradually, and converge to zero with time. Meanwhile, the control input is not saturated. An articu- lated drum roller can lock into a desired path with the proposed method in uneven fields.
基金financially supported by National Natural Science Foundation of China(No.81673363)
文摘To achieve targeted thrombolysis, a targeted delivery system of lumbrokinase(LK) was constructed using RGDfk-conjugated hybrid micelles. Based on the specific affinity of RGDfk to glycoprotein complex of GP Ⅱ b/Ⅲ a expressed on the surface of membrane of activated platelet, LK loaded targeted micelles(LKTM) can be delivered to thrombus. The hybrid micelles were composed of polycaprolactone-block-poly(2-(dimethylamino) ethyl methacrylate)(PCL-PDMAEMA), methoxy polyethylene glycol-block-polycaprolactone(mPEG-PCL)and RGDfk conjugated polycaprolactone-block-polyethylene glycol(PCL-PEG-RGDfk). PCLPDMAEMA was synthesized via ring open polymerization(ROP) and atom transfer radical polymerization(ATRP). PCL-PEG-RGDfk was synthesized via ROP and carbodiimide chemistry. The prepared LKTM was characterized by dynamic light scattering(DLS) and transmission electron microscope(TEM). Colloidal stability assay showed the prepared LKTM was stable. Biocompatibility assay was performed to determine the safe concentration range of polymer. The assay of fluorescent distribution in vivo demonstrated that LKTM can be efficiently delivered to thrombi in vivo. Thrombolysis in vivo indicated the thrombolytic potency of LKTM was optimal in all groups. Notably, the laboratory mice treated with LKTM exhibited a significantly shorter tail bleeding time compared to those treated with LK or LK-loaded micelles without RGDfk, which suggested that the targeted delivery of LK using RGDfk-conjugated hybrid micelles effectively reduced the bleeding risk.
基金This work was financially supported by the major consulting research project of the Chinese Academy of Engineering“Research on the ecological protection and high-quality development strategy of the Yellow River Basin”(2020-zd-18)the Natural Resources Defense Council(NRDC)“Project to promote the mainstreaming of Nature-based Solutions into national climate policy.”。
文摘1.Introduction We are currently facing three major ecological threats on a global scale:biodiversity loss,climate change,and environmental pollution exacerbation.The degradation of terrestrial and marine ecosystems poses a major risk to human survival and development,brings serious impacts to the wellbeing of 3.2 billion people,and causes the loss of about 10%of the annual global gross domestic product(GDP)[1,2].Meanwhile,the coronavirus disease 2019(COVID-19)epidemic is still spreading rapidly throughout the world,showing that the present relationship between humans and nature is unsustainable.It is necessary to protect nature so as to maintain the self-resilience of ecosystems.
