To contribute to the understanding of the ages of large sedimentary basins in northern Tibet, and the Cenozoic tectonic history of Asia in general, we conducted an integrated paleomagnetic and stratigraphic study on t...To contribute to the understanding of the ages of large sedimentary basins in northern Tibet, and the Cenozoic tectonic history of Asia in general, we conducted an integrated paleomagnetic and stratigraphic study on the sedimentary sequences of the Hoh Xil basin, north of the Qinghai\|Tibet Plateau. Red sedimentary sections from the Fenghuoshan and Yaxicuo Groups have recorded a pattern of magnetic polarity reversals that correlates well with the known magnetic polarity time scale for the past 56Ma. Reliable magnetostratigraphy for the Fenghuoshan and Yaxicuo Groups suggests that the sediment ages for these two groups are about 56～29Ma and 29～25Ma, respectively.We collected more than 1000 paleomagnetic samples from 335 sites distributed in 3 sections of the Hoh Xil basin. Detailed litholostratigraphic, petrologic, and sedimentologic studies have also been carried out on these sections during the past three field sessions. Magnetic directions in these sites were obtained by progressive alternating\|field and thermal demagnetization experiments. Most samples exhibit two components of magnetization. The lower unblocking temperature component is an overprint resembling the geocentric axial dipole field direction at the sampling locality. The most stable, characteristic remanence (ChRM) appears to be an early chemical remanent magnetization residing mainly in hematite. Curie temperature determinations, acquisition of isothermal remanent magnetization (IRM) and backfield demagnetization of saturation IRM, hysteresis loop parameters, and low\|temperature demagnetization on representative samples all corroborate demagnetization behavior. The positive results of fold and reversal tests indicate that the ChRM is a record of the paleomagnetic field close to the time of formation of these sediments. Further evidence that the magnetization of these sediments was acquired close to their time of deposition is the fact that patterns of magnetic reversals have been identified, which can be matched with the established polarity time scale.展开更多
China’s Chang’E-4 probe successfully landed on 3 January 2019 in Von Kármán crater within the South Pole-Aitken(SPA)basin on the lunar far side.Based on the data acquired by the scientific payloads onboard...China’s Chang’E-4 probe successfully landed on 3 January 2019 in Von Kármán crater within the South Pole-Aitken(SPA)basin on the lunar far side.Based on the data acquired by the scientific payloads onboard the lander and the rover,the researchers obtained the related information such as the geologic and tectonic setting of the landing area,compositional characteristics of the landing surface materials,dielectric permittivity and density of the lunar soil.The experiments confirmed the existence of materials dominated by olivine and low-calcium pyroxene in the SPA basin on the lunar far side,which preliminary revealed the geological evolution history of the SPA basin and even that of the early time lunar crust,as well as the tectonic setting and formation mechanism of the materials in the lunar interior.The researchers also investigated the particle radiation,Linear Energy Transaction(LET)spectrum,and so forth on the lunar surface.The low-frequency radio observations were carried out on the lunar far side for the first time as well.This article summarizes the latest scientific results in the past years,focusing on the Chang’E-4 mission.展开更多
CRESDA Application System of CBERS-1 was established in 1999. During the operation of the system for more than two years, about 240 000 scenes of CBERS-1 Level 0 data have been archived and more than 13 000 scenes of ...CRESDA Application System of CBERS-1 was established in 1999. During the operation of the system for more than two years, about 240 000 scenes of CBERS-1 Level 0 data have been archived and more than 13 000 scenes of Level 2 products have been ordered by end users from different application fields.In this paper, the typical examples of applications in crop yield estimation,calamity alleviation, resources survey and protection, environment monitoring and continuable development, and urban planning are mainly described.展开更多
CIRAD(Montpellier,France) develops research activities centered on tropical and sub-tropical agricultural systems.Among others crops,cotton is the focus of a series of research programs in different disciplines from e...CIRAD(Montpellier,France) develops research activities centered on tropical and sub-tropical agricultural systems.Among others crops,cotton is the focus of a series of research programs in different disciplines from economics to breeding.Major areas in genetics and breeding relate to(1) genetic diversity,(2) cultivar development through classical and molecular breeding,and(3)展开更多
Journal of Future Foods(ISSN 2772-5669.Owner:Bejjing Academy of Food Sciences.Production and Hosting:Elsevier B.V.on bchalf of KcAi Communications Co,Ltd.)is an intecrnational,pcer-reviewed open access journal bclongi...Journal of Future Foods(ISSN 2772-5669.Owner:Bejjing Academy of Food Sciences.Production and Hosting:Elsevier B.V.on bchalf of KcAi Communications Co,Ltd.)is an intecrnational,pcer-reviewed open access journal bclonging to the disciplinc of food scicnce and technology.The aim of the journal is to report latcst rescarch results of high-tcch in food science.We welcome submissions that drive the ficld of food science towards whole food nutrition,intelligencc and high technology.展开更多
zack et al.(2004a)、Watson et al.(2006)以及Tomkins et al.(2007)(在2GPa条件下)的金红石中锆含量温度计计算结果显示,徐淮地区中生代侵入杂岩所含榴辉岩类包体所经历的榴辉岩相变质的温度范围分别为776～1099℃(平均898℃)、663～92...zack et al.(2004a)、Watson et al.(2006)以及Tomkins et al.(2007)(在2GPa条件下)的金红石中锆含量温度计计算结果显示,徐淮地区中生代侵入杂岩所含榴辉岩类包体所经历的榴辉岩相变质的温度范围分别为776～1099℃(平均898℃)、663～923℃(平均750℃)和714～981℃(平均804℃),这些温度结果可能并非榴辉岩相峰期变质温度;其角闪岩相退变质作用过程中保存的温度范围分别为555～777℃(平均697℃)、541～663℃(平均617℃)和588～714℃(平均667℃),这些结果不能代表角闪岩相退变质再平衡后的温度,而只能代表角闪岩相退变质作用过程中某一阶段的温度。微量元素地球化学特征研究表明,榴辉岩类包体所含金红石中的某些微量元素(如Nb、Ta、Cr、Fe、V等)含量与其原岩有继承和对应关系,其原岩主要为镁铁质岩石;榴辉岩类包体与其寄主岩石中部分高价态/高场强元素(HFSE)呈相互消长的关系。榴辉岩的形成与扬子地块和华北地块之间的俯冲-碰撞作用有关。展开更多
将粒子群优化(PSO)算法与BP神经网络相结合,应用在传感器静态非线性特性的校正中.用PSO算法所得到的全局最优值作为BP神经网络的初始权值,训练BP神经网络,训练结束后的神经网络作为传感器的静态特性校正器.应用结果表明,该方法可以提高B...将粒子群优化(PSO)算法与BP神经网络相结合,应用在传感器静态非线性特性的校正中.用PSO算法所得到的全局最优值作为BP神经网络的初始权值,训练BP神经网络,训练结束后的神经网络作为传感器的静态特性校正器.应用结果表明,该方法可以提高BP神经网络的精度,并且该神经网络具有良好的泛化能力.
Abstract：
A static nonlinear errors method for correcting the sensors based on BP neural network using particle swarm optimization (PSO) is described. The global best values of particle swarm are used as initial weights of BP neural network to train BP neural network. Then the trained neural network is regarded as the sensor's corrector. The application results show that this method can improve the precision of the BP neural network, and the generalization capability of the neural network is good.展开更多
提出了一种基于最小二乘支持向量机的织物剪切性能预测模型,并且采用遗传算法进行最小二乘支持向量机的参数优化,将获得的样本进行归一化处理后,将其输入预测模型以得到预测结果.仿真结果表明,基于最小二乘支持向量机的预测模型比BP神...提出了一种基于最小二乘支持向量机的织物剪切性能预测模型,并且采用遗传算法进行最小二乘支持向量机的参数优化,将获得的样本进行归一化处理后,将其输入预测模型以得到预测结果.仿真结果表明,基于最小二乘支持向量机的预测模型比BP神经网络和线性回归方法具有更高的精度和范化能力.
Abstract：
A new method is proposed to predict the fabric shearing property with least square support vector machines ( LS-SVM ). The genetic algorithm is investigated to select the parameters of LS-SVM models as a means of improving the LS- SVM prediction. After normalizing the sampling data, the sampling data are inputted into the model to gain the prediction result. The simulation results show the prediction model gives better forecasting accuracy and generalization ability than BP neural network and linear regression method.展开更多
根据砝码磁性参数的测量原理,针对磁性测量中示值稳定性的影响量进行分析,提出影响砝码磁性参数测量中示值稳定性的关键影响量.采用最大称量5.1 g、分辨率0.1μg的磁化率计进行砝码磁性测量,测量过程中分别同步测试振动的变化和环境磁...根据砝码磁性参数的测量原理,针对磁性测量中示值稳定性的影响量进行分析,提出影响砝码磁性参数测量中示值稳定性的关键影响量.采用最大称量5.1 g、分辨率0.1μg的磁化率计进行砝码磁性测量,测量过程中分别同步测试振动的变化和环境磁场的变化,通过实验数据分析,验证了环境磁场的波动是影响砝码磁性测量的关键影响量.Abstract：According to the measurement principle of weight magnetic parameter, the influence of reading stability for measuring magnetism is analyzed, and the key influence of reading stability is presented in the measurement process. The magnetism of weight is measured by the magnetic susceptometer with capacity of 5.1 g and resolution of O. 1 μg. At the same time the change of environmental vibration in the laboratory and the fluctuating of ambient magnetic field are measured respectively. The experimental results show the fluctuating of ambient magnetic field that is the key influence of weight magnetism measurement.展开更多
Recent experimental results of the Doppler effect formula verification are reported. The moving emitters are hydrogen atoms in the excited state. The results of the work corroborate the classical not the relativistic,...Recent experimental results of the Doppler effect formula verification are reported. The moving emitters are hydrogen atoms in the excited state. The results of the work corroborate the classical not the relativistic,formula for the Doppler effect.展开更多
With the development of large scale text processing, the dimension of text feature space has become larger and larger, which has added a lot of difficulties to natural language processing. How to reduce the dimension...With the development of large scale text processing, the dimension of text feature space has become larger and larger, which has added a lot of difficulties to natural language processing. How to reduce the dimension has become a practical problem in the field. Here we present two clustering methods, i.e. concept association and concept abstract, to achieve the goal. The first refers to the keyword clustering based on the co occurrence of展开更多
The main contribution of this paper is the design of an event-triggered formation control for leader-following consensus in second-order multi-agent systems(MASs)under communication faults.All the agents must follow t...The main contribution of this paper is the design of an event-triggered formation control for leader-following consensus in second-order multi-agent systems(MASs)under communication faults.All the agents must follow the trajectories of a virtual leader despite communication faults considered as smooth time-varying delays dependent on the distance between the agents.Linear matrix inequalities(LMIs)-based conditions are obtained to synthesize a controller gain that guarantees stability of the synchronization error.Based on the closed-loop system,an event-triggered mechanism is designed to reduce the control law update and information exchange in order to reduce energy consumption.The proposed approach is implemented in a real platform of a fleet of unmanned aerial vehicles(UAVs)under communication faults.A comparison between a state-of-the-art technique and the proposed technique has been provided,demonstrating the performance improvement brought by the proposed approach.展开更多
Chang'E-1, the first lunar mission in China, was successfully launched on October 24,2007, which opened the prelude of China's Lunar Exploration Program. Later on, the Chang'E-2 and Chang'E-3 satellite...Chang'E-1, the first lunar mission in China, was successfully launched on October 24,2007, which opened the prelude of China's Lunar Exploration Program. Later on, the Chang'E-2 and Chang'E-3 satellites were successfully launched in 2010 and 2013, respectively. In order to achieve the science objectives, various payloads boarded the spacecraft. The scientific data from these instruments were received by Beijing and Kunming ground stations simultaneously. Up to now, about 5.628 Terabytes of raw data were received totally. A series of research results has been achieved. This paper presents a brief introduction to the main scientific results and latest progress from Chang'E-3 mission.展开更多
文摘To contribute to the understanding of the ages of large sedimentary basins in northern Tibet, and the Cenozoic tectonic history of Asia in general, we conducted an integrated paleomagnetic and stratigraphic study on the sedimentary sequences of the Hoh Xil basin, north of the Qinghai\|Tibet Plateau. Red sedimentary sections from the Fenghuoshan and Yaxicuo Groups have recorded a pattern of magnetic polarity reversals that correlates well with the known magnetic polarity time scale for the past 56Ma. Reliable magnetostratigraphy for the Fenghuoshan and Yaxicuo Groups suggests that the sediment ages for these two groups are about 56～29Ma and 29～25Ma, respectively.We collected more than 1000 paleomagnetic samples from 335 sites distributed in 3 sections of the Hoh Xil basin. Detailed litholostratigraphic, petrologic, and sedimentologic studies have also been carried out on these sections during the past three field sessions. Magnetic directions in these sites were obtained by progressive alternating\|field and thermal demagnetization experiments. Most samples exhibit two components of magnetization. The lower unblocking temperature component is an overprint resembling the geocentric axial dipole field direction at the sampling locality. The most stable, characteristic remanence (ChRM) appears to be an early chemical remanent magnetization residing mainly in hematite. Curie temperature determinations, acquisition of isothermal remanent magnetization (IRM) and backfield demagnetization of saturation IRM, hysteresis loop parameters, and low\|temperature demagnetization on representative samples all corroborate demagnetization behavior. The positive results of fold and reversal tests indicate that the ChRM is a record of the paleomagnetic field close to the time of formation of these sediments. Further evidence that the magnetization of these sediments was acquired close to their time of deposition is the fact that patterns of magnetic reversals have been identified, which can be matched with the established polarity time scale.
基金Supported by National Key R&D Program of China(2020YFE0202100)Beijing Municipal Science and Technology Commission(Z181100002918003)。
文摘China’s Chang’E-4 probe successfully landed on 3 January 2019 in Von Kármán crater within the South Pole-Aitken(SPA)basin on the lunar far side.Based on the data acquired by the scientific payloads onboard the lander and the rover,the researchers obtained the related information such as the geologic and tectonic setting of the landing area,compositional characteristics of the landing surface materials,dielectric permittivity and density of the lunar soil.The experiments confirmed the existence of materials dominated by olivine and low-calcium pyroxene in the SPA basin on the lunar far side,which preliminary revealed the geological evolution history of the SPA basin and even that of the early time lunar crust,as well as the tectonic setting and formation mechanism of the materials in the lunar interior.The researchers also investigated the particle radiation,Linear Energy Transaction(LET)spectrum,and so forth on the lunar surface.The low-frequency radio observations were carried out on the lunar far side for the first time as well.This article summarizes the latest scientific results in the past years,focusing on the Chang’E-4 mission.
基金Supported by the National Natural Science Foundation of China through grant No.49790020
文摘CRESDA Application System of CBERS-1 was established in 1999. During the operation of the system for more than two years, about 240 000 scenes of CBERS-1 Level 0 data have been archived and more than 13 000 scenes of Level 2 products have been ordered by end users from different application fields.In this paper, the typical examples of applications in crop yield estimation,calamity alleviation, resources survey and protection, environment monitoring and continuable development, and urban planning are mainly described.
文摘CIRAD(Montpellier,France) develops research activities centered on tropical and sub-tropical agricultural systems.Among others crops,cotton is the focus of a series of research programs in different disciplines from economics to breeding.Major areas in genetics and breeding relate to(1) genetic diversity,(2) cultivar development through classical and molecular breeding,and(3)
文摘Journal of Future Foods(ISSN 2772-5669.Owner:Bejjing Academy of Food Sciences.Production and Hosting:Elsevier B.V.on bchalf of KcAi Communications Co,Ltd.)is an intecrnational,pcer-reviewed open access journal bclonging to the disciplinc of food scicnce and technology.The aim of the journal is to report latcst rescarch results of high-tcch in food science.We welcome submissions that drive the ficld of food science towards whole food nutrition,intelligencc and high technology.
文摘zack et al.(2004a)、Watson et al.(2006)以及Tomkins et al.(2007)(在2GPa条件下)的金红石中锆含量温度计计算结果显示,徐淮地区中生代侵入杂岩所含榴辉岩类包体所经历的榴辉岩相变质的温度范围分别为776～1099℃(平均898℃)、663～923℃(平均750℃)和714～981℃(平均804℃),这些温度结果可能并非榴辉岩相峰期变质温度;其角闪岩相退变质作用过程中保存的温度范围分别为555～777℃(平均697℃)、541～663℃(平均617℃)和588～714℃(平均667℃),这些结果不能代表角闪岩相退变质再平衡后的温度,而只能代表角闪岩相退变质作用过程中某一阶段的温度。微量元素地球化学特征研究表明,榴辉岩类包体所含金红石中的某些微量元素(如Nb、Ta、Cr、Fe、V等)含量与其原岩有继承和对应关系,其原岩主要为镁铁质岩石;榴辉岩类包体与其寄主岩石中部分高价态/高场强元素(HFSE)呈相互消长的关系。榴辉岩的形成与扬子地块和华北地块之间的俯冲-碰撞作用有关。
文摘将粒子群优化(PSO)算法与BP神经网络相结合,应用在传感器静态非线性特性的校正中.用PSO算法所得到的全局最优值作为BP神经网络的初始权值,训练BP神经网络,训练结束后的神经网络作为传感器的静态特性校正器.应用结果表明,该方法可以提高BP神经网络的精度,并且该神经网络具有良好的泛化能力.
Abstract：
A static nonlinear errors method for correcting the sensors based on BP neural network using particle swarm optimization (PSO) is described. The global best values of particle swarm are used as initial weights of BP neural network to train BP neural network. Then the trained neural network is regarded as the sensor's corrector. The application results show that this method can improve the precision of the BP neural network, and the generalization capability of the neural network is good.
文摘提出了一种基于最小二乘支持向量机的织物剪切性能预测模型,并且采用遗传算法进行最小二乘支持向量机的参数优化,将获得的样本进行归一化处理后,将其输入预测模型以得到预测结果.仿真结果表明,基于最小二乘支持向量机的预测模型比BP神经网络和线性回归方法具有更高的精度和范化能力.
Abstract：
A new method is proposed to predict the fabric shearing property with least square support vector machines ( LS-SVM ). The genetic algorithm is investigated to select the parameters of LS-SVM models as a means of improving the LS- SVM prediction. After normalizing the sampling data, the sampling data are inputted into the model to gain the prediction result. The simulation results show the prediction model gives better forecasting accuracy and generalization ability than BP neural network and linear regression method.
文摘根据砝码磁性参数的测量原理,针对磁性测量中示值稳定性的影响量进行分析,提出影响砝码磁性参数测量中示值稳定性的关键影响量.采用最大称量5.1 g、分辨率0.1μg的磁化率计进行砝码磁性测量,测量过程中分别同步测试振动的变化和环境磁场的变化,通过实验数据分析,验证了环境磁场的波动是影响砝码磁性测量的关键影响量.Abstract：According to the measurement principle of weight magnetic parameter, the influence of reading stability for measuring magnetism is analyzed, and the key influence of reading stability is presented in the measurement process. The magnetism of weight is measured by the magnetic susceptometer with capacity of 5.1 g and resolution of O. 1 μg. At the same time the change of environmental vibration in the laboratory and the fluctuating of ambient magnetic field are measured respectively. The experimental results show the fluctuating of ambient magnetic field that is the key influence of weight magnetism measurement.
文摘Recent experimental results of the Doppler effect formula verification are reported. The moving emitters are hydrogen atoms in the excited state. The results of the work corroborate the classical not the relativistic,formula for the Doppler effect.
文摘With the development of large scale text processing, the dimension of text feature space has become larger and larger, which has added a lot of difficulties to natural language processing. How to reduce the dimension has become a practical problem in the field. Here we present two clustering methods, i.e. concept association and concept abstract, to achieve the goal. The first refers to the keyword clustering based on the co occurrence of
文摘The main contribution of this paper is the design of an event-triggered formation control for leader-following consensus in second-order multi-agent systems(MASs)under communication faults.All the agents must follow the trajectories of a virtual leader despite communication faults considered as smooth time-varying delays dependent on the distance between the agents.Linear matrix inequalities(LMIs)-based conditions are obtained to synthesize a controller gain that guarantees stability of the synchronization error.Based on the closed-loop system,an event-triggered mechanism is designed to reduce the control law update and information exchange in order to reduce energy consumption.The proposed approach is implemented in a real platform of a fleet of unmanned aerial vehicles(UAVs)under communication faults.A comparison between a state-of-the-art technique and the proposed technique has been provided,demonstrating the performance improvement brought by the proposed approach.
基金Supported by the NSFC under Grant(41073053)the Key Research Program of the Chinese Academy of Sciencesunder Grant(KGZD-EW-603)
文摘Chang'E-1, the first lunar mission in China, was successfully launched on October 24,2007, which opened the prelude of China's Lunar Exploration Program. Later on, the Chang'E-2 and Chang'E-3 satellites were successfully launched in 2010 and 2013, respectively. In order to achieve the science objectives, various payloads boarded the spacecraft. The scientific data from these instruments were received by Beijing and Kunming ground stations simultaneously. Up to now, about 5.628 Terabytes of raw data were received totally. A series of research results has been achieved. This paper presents a brief introduction to the main scientific results and latest progress from Chang'E-3 mission.
