Thermal comfort evaluations for Yuexiu Park,Lushan Park,and Baiyun Lake Park in Guangzhou were conducted using field meteorological data collection,visitor questionnaires,and literature reviews.It analyzed the impact ...Thermal comfort evaluations for Yuexiu Park,Lushan Park,and Baiyun Lake Park in Guangzhou were conducted using field meteorological data collection,visitor questionnaires,and literature reviews.It analyzed the impact of green coverage,water body layout,and facility configuration on thermal comfort.The results showed that good green and water body design effectively lowered the temperature in the park and improved the thermal comfort of visitors,but the insufficient facility configuration in some open areas affected the experience.The visitor’s experience is closely related to the natural environment and facility layout of the park.Therefore,in the future,park design should pay more attention to the rational configuration of shading,ventilation,and cooling facilities to improve thermal comfort,and encourage citizens to participate in the construction and management of parks to improve ecological quality and user experience.This study provides a reference for the improvement of thermal comfort in urban parks in Guangzhou and aims to promote the sustainable and human-oriented development of urban park design.展开更多
High-precision microelectromechanical system(MEMS)gyroscopes are significant in many applications.Bias instability(BI)is an important parameter that indicates the performance of a MEMS gyroscope and is affected by the...High-precision microelectromechanical system(MEMS)gyroscopes are significant in many applications.Bias instability(BI)is an important parameter that indicates the performance of a MEMS gyroscope and is affected by the 1/f noise of the MEMS resonator and readout circuit.Since the bandgap reference(BGR)is an important block in the readout circuit,reducing its 1/f noise is key to improving a gyroscope's Bl.In a traditional BGR,the error amplifer is applied to provide a virtual short-circuit point,but it introduces the main low-frequency noise sources.This paper proposes an ultralow 1/f noise BGR by removing the error amplifer and applying an optimized circuit topology.In addition,a simplified but accurate noise model of the proposed BGR is obtained to optimize the BGR's output noise performance.To verify this design,the proposed BGR has been implemented in a 180 nm CMOS process with a chip area of 545×423μm.The experimental results show that the BGR's output integrated noise from 0.1 to 10 Hz is 0.82μV and the thermal noise is 35 nV/√Hz.Furthermore,bias stability tests of the MEMS gyroscope fabricated in our laboratory with the proposed BGR and some commercial BGRs are carried out.Statistical results show that reducing the BGR's 1/f noisecannearly linearly improvethegyroscope's Bl.展开更多
文摘Thermal comfort evaluations for Yuexiu Park,Lushan Park,and Baiyun Lake Park in Guangzhou were conducted using field meteorological data collection,visitor questionnaires,and literature reviews.It analyzed the impact of green coverage,water body layout,and facility configuration on thermal comfort.The results showed that good green and water body design effectively lowered the temperature in the park and improved the thermal comfort of visitors,but the insufficient facility configuration in some open areas affected the experience.The visitor’s experience is closely related to the natural environment and facility layout of the park.Therefore,in the future,park design should pay more attention to the rational configuration of shading,ventilation,and cooling facilities to improve thermal comfort,and encourage citizens to participate in the construction and management of parks to improve ecological quality and user experience.This study provides a reference for the improvement of thermal comfort in urban parks in Guangzhou and aims to promote the sustainable and human-oriented development of urban park design.
基金support from the National Natural Science Foundation of China under grant No.92164203.
文摘High-precision microelectromechanical system(MEMS)gyroscopes are significant in many applications.Bias instability(BI)is an important parameter that indicates the performance of a MEMS gyroscope and is affected by the 1/f noise of the MEMS resonator and readout circuit.Since the bandgap reference(BGR)is an important block in the readout circuit,reducing its 1/f noise is key to improving a gyroscope's Bl.In a traditional BGR,the error amplifer is applied to provide a virtual short-circuit point,but it introduces the main low-frequency noise sources.This paper proposes an ultralow 1/f noise BGR by removing the error amplifer and applying an optimized circuit topology.In addition,a simplified but accurate noise model of the proposed BGR is obtained to optimize the BGR's output noise performance.To verify this design,the proposed BGR has been implemented in a 180 nm CMOS process with a chip area of 545×423μm.The experimental results show that the BGR's output integrated noise from 0.1 to 10 Hz is 0.82μV and the thermal noise is 35 nV/√Hz.Furthermore,bias stability tests of the MEMS gyroscope fabricated in our laboratory with the proposed BGR and some commercial BGRs are carried out.Statistical results show that reducing the BGR's 1/f noisecannearly linearly improvethegyroscope's Bl.
