Improving knowledge on the ability of bioengineering structures made of willow cuttings to enhance efficient and sustainable sediment trapping in marly gullies in the Southern French Alps under a mountainous Mediterra...Improving knowledge on the ability of bioengineering structures made of willow cuttings to enhance efficient and sustainable sediment trapping in marly gullies in the Southern French Alps under a mountainous Mediterranean climate, to decreasesediment trapped per experiment, the mean annual values reached 0.25, 0.14 and 0.08 m3 yr-1 in experiments C, A and B, respectively. Maximum values for one structure reached 1.94 m3 per year in experiment C. The significance of the volumes ofsediment yield at their outlets, is a key issue today for the international scientific community working in geosciences and ecology. This study therefore aims to assess three real-size experiments(A, B and C) carried out between 2003 and 2013 in this environment. A total of 157 bioengineering structures using purple and white willow(Salix purpurea and Salix incana)cuttings – which have been shown to resprout and survive more than 2 years after their installation,corresponding to brush layers with brush mats on wooden sills(BLM), 1.2 m wide and 2 m long,installed on the floors of 33 experimental marly gullies, were monitored. The results showed that sediment trapping occurred upstream of the vegetation barriers from the 1 st year onwards.Considering the depth of sediment trapped per experiment, the mean annual values reached 11.2 cm yr-1 after 3 years in experiment A, 7.7 cm yr-1 after 2–4 years in experiment C and 5.1 cm yr-1 after 5 years in experiment B. Occasionally, BLMs showed that they could trap up to 16 and 15 cm yr-1 in experiments A and C, respectively. Considering the volumes oftrapped sediment and the sustainability of sediment trapping are discussed, and rules for bioengineering strategies are proposed.展开更多
该文运用Dlib人脸检测模型与人脸检测模板匹配方法,通过计算EAR、MAR、pitch、yaw和roll参数,采用多阈值判定研究疲驾驶员疲劳状态,并将该算法在Raspberry Pi 5硬件平台实现,搭建疲劳驾驶检测预警系统,最后通过公开数据集验证该系统对...该文运用Dlib人脸检测模型与人脸检测模板匹配方法,通过计算EAR、MAR、pitch、yaw和roll参数,采用多阈值判定研究疲驾驶员疲劳状态,并将该算法在Raspberry Pi 5硬件平台实现,搭建疲劳驾驶检测预警系统,最后通过公开数据集验证该系统对于驾驶员面部疲劳状态检测及提醒的准确性和良好的系统性能。EAR、MAR、HPE 3种判断准则在公开数据集Drowsiness、YawDD及自制数据集上分别达到95.6%、96%与96%的平均正确率;在面部无遮挡的情况下,该系统实时帧率达到20 FPS,基本可实时对驾驶员疲劳状态作出相应提醒,同时具备较高的准确率。展开更多
The parachute deployment conditions during the terminal entry phase in Mars landing missions exhibit critical impact on landing precision.In this article,aiming at the requirements of safe parachute deployment and acc...The parachute deployment conditions during the terminal entry phase in Mars landing missions exhibit critical impact on landing precision.In this article,aiming at the requirements of safe parachute deployment and accurate landing,a multidimensional parachute deployment box for determining deployment condition during Mars landing was proposed.First,an extremerange optimization model was established,synthesizing the dynamics and constraints of both parachute descent and powered descent phases.Then,on the basis of the two-dimensional altitude-velocity deployment box,a multi-dimensional parachute deployment box characterized by altitude,velocity,flight-path angle,and extreme range was constructed through the integration of extreme range information.Furthermore,an evaluation index for landing precision was formulated and a deployment control logic was proposed for minimizing landing deviation.Finally,the proposed deployment box was simulated in a Mars landing mission.The results demonstrate that the proposed box effectively satisfies safe deployment and landing precision demands,eliminating the range-to-go error at the terminal of the entry phase.展开更多
Dear Editor,This letter proposes a convex optimization-based model predictive control(MPC)autonomous guidance method for the Mars ascent vehicle(MAV).We use the modified chebyshev-picard iteration(MCPI)to solve optimi...Dear Editor,This letter proposes a convex optimization-based model predictive control(MPC)autonomous guidance method for the Mars ascent vehicle(MAV).We use the modified chebyshev-picard iteration(MCPI)to solve optimization sub-problems within the MPC framework,eliminating the dynamic constraints in solving the optimal control problem and enhancing the convergence performance of the algorithm.Moreover,this method can repeatedly perform trajectory optimization calculations at a high frequency,achieving timely correction of the optimal control command.Numerical simulations demonstrate that the method can satisfy the requirements of rapid computation and reliability for the MAV system when considering uncertainties and perturbations.展开更多
Medically assisted reproduction(MAR)techniques are highly dependent on the sperm quantity and quality.Low sperm concentrations can be bypassed at least to some point by the usage of more sophisticated MAR techniques l...Medically assisted reproduction(MAR)techniques are highly dependent on the sperm quantity and quality.Low sperm concentrations can be bypassed at least to some point by the usage of more sophisticated MAR techniques like intracytoplasmic sperm injection(ICSI).Compared to this,disruptions in established indicators of sperm quality like motility or morphology pose greater challenges for the therapy of couple infertility.展开更多
In this study, we present an innovative Mars Ionosphere-Thermosphere Model(MITM), which is a time-dependent, threedimensional(3-D) model that comprehensively represents the self-consistently coupled thermosphere and i...In this study, we present an innovative Mars Ionosphere-Thermosphere Model(MITM), which is a time-dependent, threedimensional(3-D) model that comprehensively represents the self-consistently coupled thermosphere and ionosphere of Mars within the altitude range of 70-300 km. The model incorporates an extensive range of parameters, including neutral number densities of CO_(2), CO,O, O_(2), N_(2), NO, N(^(2)D), N(^(4)S), Ar, and He;ion number densities of CO_(2)^(+), CO^(+), O^(+), O_(2)^(+), N_(2)^(+), NO^(+), N^(+) ions, and electrons;neutral temperature;and neutral wind fields. The MITM code employs a high-resolution grid system in a spherical geographical coordinate system, with a horizontal resolution of 5° latitude by 7.5° longitude. This altitude-resolved grid system enables accurate depiction of spatial variations in the Martian thermosphere and ionosphere. To showcase the capabilities of the MITM, we present two simulation cases: one during the equinox and another during the solstice. Both simulations reproduce key features of the Martian thermosphere and ionosphere including the characteristics of horizontal circulation, diurnal variations in chemical composition, and distribution of electron density. The MITM offers a robust framework for understanding the intricate interactions and processes that shape the Mars thermosphere and ionosphere,which are crucial for enhancing our understanding of Martian upper atmosphere and ionosphere.展开更多
The InSight mission has obtained seismic data from Mars,offering new insights into the planet’s internal structure and seismic activity.However,the raw data released to the public contain various sources of noise,suc...The InSight mission has obtained seismic data from Mars,offering new insights into the planet’s internal structure and seismic activity.However,the raw data released to the public contain various sources of noise,such as ticks and glitches,which hamper further seismological studies.This paper presents step-by-step processing of InSight’s Very Broad Band seismic data,focusing on the suppression and removal of non-seismic noise.The processing stages include tick noise removal,glitch signal suppression,multicomponent synchronization,instrument response correction,and rotation of orthogonal components.The processed datasets and associated codes are openly accessible and will support ongoing efforts to explore the geophysical properties of Mars and contribute to the broader field of planetary seismology.展开更多
基金Electricitéde France(EDF)Agence de l’eau Rh?ne+3 种基金Méditerranée et CorseRégion Provence-Alpes-Cote-d’Azurthe European Union("L’Europe s’engage en PACA avec le Fonds Européen de Développement Régional"FEDER program)the Ministère de l’environnement,de l’énergie et de la mer(MEEM)
文摘Improving knowledge on the ability of bioengineering structures made of willow cuttings to enhance efficient and sustainable sediment trapping in marly gullies in the Southern French Alps under a mountainous Mediterranean climate, to decreasesediment trapped per experiment, the mean annual values reached 0.25, 0.14 and 0.08 m3 yr-1 in experiments C, A and B, respectively. Maximum values for one structure reached 1.94 m3 per year in experiment C. The significance of the volumes ofsediment yield at their outlets, is a key issue today for the international scientific community working in geosciences and ecology. This study therefore aims to assess three real-size experiments(A, B and C) carried out between 2003 and 2013 in this environment. A total of 157 bioengineering structures using purple and white willow(Salix purpurea and Salix incana)cuttings – which have been shown to resprout and survive more than 2 years after their installation,corresponding to brush layers with brush mats on wooden sills(BLM), 1.2 m wide and 2 m long,installed on the floors of 33 experimental marly gullies, were monitored. The results showed that sediment trapping occurred upstream of the vegetation barriers from the 1 st year onwards.Considering the depth of sediment trapped per experiment, the mean annual values reached 11.2 cm yr-1 after 3 years in experiment A, 7.7 cm yr-1 after 2–4 years in experiment C and 5.1 cm yr-1 after 5 years in experiment B. Occasionally, BLMs showed that they could trap up to 16 and 15 cm yr-1 in experiments A and C, respectively. Considering the volumes oftrapped sediment and the sustainability of sediment trapping are discussed, and rules for bioengineering strategies are proposed.
文摘该文运用Dlib人脸检测模型与人脸检测模板匹配方法,通过计算EAR、MAR、pitch、yaw和roll参数,采用多阈值判定研究疲驾驶员疲劳状态,并将该算法在Raspberry Pi 5硬件平台实现,搭建疲劳驾驶检测预警系统,最后通过公开数据集验证该系统对于驾驶员面部疲劳状态检测及提醒的准确性和良好的系统性能。EAR、MAR、HPE 3种判断准则在公开数据集Drowsiness、YawDD及自制数据集上分别达到95.6%、96%与96%的平均正确率;在面部无遮挡的情况下,该系统实时帧率达到20 FPS,基本可实时对驾驶员疲劳状态作出相应提醒,同时具备较高的准确率。
基金Supported by the National Natural Science Foundation of China(62073034)。
文摘The parachute deployment conditions during the terminal entry phase in Mars landing missions exhibit critical impact on landing precision.In this article,aiming at the requirements of safe parachute deployment and accurate landing,a multidimensional parachute deployment box for determining deployment condition during Mars landing was proposed.First,an extremerange optimization model was established,synthesizing the dynamics and constraints of both parachute descent and powered descent phases.Then,on the basis of the two-dimensional altitude-velocity deployment box,a multi-dimensional parachute deployment box characterized by altitude,velocity,flight-path angle,and extreme range was constructed through the integration of extreme range information.Furthermore,an evaluation index for landing precision was formulated and a deployment control logic was proposed for minimizing landing deviation.Finally,the proposed deployment box was simulated in a Mars landing mission.The results demonstrate that the proposed box effectively satisfies safe deployment and landing precision demands,eliminating the range-to-go error at the terminal of the entry phase.
基金supported by the National Defense Basic Scientific Research Program(JCKY2021603B030)the National Natural Science Foundation of China(62273118,12150008)the Natural Science Foundation of Heilongjiang Province(LH2022F023).
文摘Dear Editor,This letter proposes a convex optimization-based model predictive control(MPC)autonomous guidance method for the Mars ascent vehicle(MAV).We use the modified chebyshev-picard iteration(MCPI)to solve optimization sub-problems within the MPC framework,eliminating the dynamic constraints in solving the optimal control problem and enhancing the convergence performance of the algorithm.Moreover,this method can repeatedly perform trajectory optimization calculations at a high frequency,achieving timely correction of the optimal control command.Numerical simulations demonstrate that the method can satisfy the requirements of rapid computation and reliability for the MAV system when considering uncertainties and perturbations.
文摘Medically assisted reproduction(MAR)techniques are highly dependent on the sperm quantity and quality.Low sperm concentrations can be bypassed at least to some point by the usage of more sophisticated MAR techniques like intracytoplasmic sperm injection(ICSI).Compared to this,disruptions in established indicators of sperm quality like motility or morphology pose greater challenges for the therapy of couple infertility.
基金This work is supported by the B-type Strategic Priority Program of the Chinese Academy of Sciences (Grant No. XDB4100000)the pre-research Project on Civil Aerospace Technologies No. D020105 funded by CNSAthe Strategic Priority Research Program of Chinese Academy of Sciences (Grant XDA17010404, XDA17010201)。
文摘In this study, we present an innovative Mars Ionosphere-Thermosphere Model(MITM), which is a time-dependent, threedimensional(3-D) model that comprehensively represents the self-consistently coupled thermosphere and ionosphere of Mars within the altitude range of 70-300 km. The model incorporates an extensive range of parameters, including neutral number densities of CO_(2), CO,O, O_(2), N_(2), NO, N(^(2)D), N(^(4)S), Ar, and He;ion number densities of CO_(2)^(+), CO^(+), O^(+), O_(2)^(+), N_(2)^(+), NO^(+), N^(+) ions, and electrons;neutral temperature;and neutral wind fields. The MITM code employs a high-resolution grid system in a spherical geographical coordinate system, with a horizontal resolution of 5° latitude by 7.5° longitude. This altitude-resolved grid system enables accurate depiction of spatial variations in the Martian thermosphere and ionosphere. To showcase the capabilities of the MITM, we present two simulation cases: one during the equinox and another during the solstice. Both simulations reproduce key features of the Martian thermosphere and ionosphere including the characteristics of horizontal circulation, diurnal variations in chemical composition, and distribution of electron density. The MITM offers a robust framework for understanding the intricate interactions and processes that shape the Mars thermosphere and ionosphere,which are crucial for enhancing our understanding of Martian upper atmosphere and ionosphere.
基金supported by the National Key R&D Program of China(Nos.2022YFF 0503203 and 2024YFF0809900)the Research Funds of the Institute of Geophysics,China Earthquake Administration(No.DQJB24X28)the National Natural Science Foundation of China(Nos.42474226 and 42441827).
文摘The InSight mission has obtained seismic data from Mars,offering new insights into the planet’s internal structure and seismic activity.However,the raw data released to the public contain various sources of noise,such as ticks and glitches,which hamper further seismological studies.This paper presents step-by-step processing of InSight’s Very Broad Band seismic data,focusing on the suppression and removal of non-seismic noise.The processing stages include tick noise removal,glitch signal suppression,multicomponent synchronization,instrument response correction,and rotation of orthogonal components.The processed datasets and associated codes are openly accessible and will support ongoing efforts to explore the geophysical properties of Mars and contribute to the broader field of planetary seismology.
