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Study on the upper ocean is of great significance to the global climate change and carbon cycle. Lidar can be used to effectively detect depth-resolved optical properties of the ocean. However, both theory and experiment of oceanic lidar are limited by complex multiple scattering. Several progresses by Zhejiang University will be illustrated in this paper: 1) a polarized lidar system was developed, and a Monte Carlo model and a radiative transfer model were established (Zhou, et al. remote sensing, 2019; Zhou, et al. Journal of remote sensing, 2019; Xu, et al. and Liu, et al. Journal of remote sensing, 2019); 2) Cross validations are demonstrated to verify the availability of the lidar system and models (Liu, et al. IEEE TGRS, 2019); 3) phase function effects on backscatter and attenuation are studied considering multiple scattering, respectively (Liu, et al. Optics Express, 2019). Oceanic lidar is proven to have great potential in marine studies.

Multiple scattering is an inevitable effect in spaceborne oceanic lidar because of the large footprint size and the high optical density of seawater. The effective attenuation coefficient klidar in oceanic lidar equation, which indicates the influence of the multiple scattering effect on the formation of lidar returns, is an important parameter in the retrieval of inherent optical properties (IOPs) of seawater. In this paper, the nonlinearity of klidar and the relationships between klidar and the IOPs of seawater are investigated by solving the radiative transfer equation with an improved semianalytic Monte Carlo model. klidar is found to decrease exponentially with the increase of depth in homogeneous waters. klidar is given as an exponential function of depth and IOPs of seawater. The results in this paper can help to have a better understanding of the multiple scattering effect of spaceborne lidar and improve the retrieval accuracy of the IOPs of seawater using spaceborne lidar.

In this paper, a new degradation model of the more electrical aircraft (MEA) actuation system is proposed. The bond graph model is used to build the dissimilar redundancy actuation system model, taking into account the degradation behavior (wear, fatigue, aging) of components in the system operation and the fault coupling phenomenon caused by the accumulation of dissipated energy in space and time, and a fault coupling degradation model of the actuation system is established with clear mechanism support. Through the fault mechanism analysis, various fault types are injected into the bond graph model of the actuation system, and the simulation results are compared. The influence of fault propagation on system output is analyzed, the system's reliability is assessed, and the performance evaluation of the actuation system is realized while taking the fault coupling mechanism into account. [ABSTRACT FROM AUTHOR]

Lack of phosphorus (P) is a major environmental factor affecting rapeseed (Brassica napus. L) root growth and development. For breeding purposes, it is crucial to identify the molecular mechanisms underlying root system architecture traits that confer low-P tolerance in rapeseed. Natural variations in the glycine-rich protein gene BnGRP1 were analysed in the natural population of 400 rapeseed cultivars under low-P stress through genome-wide association study and transcriptome analysis. Based on 11 single nucleotide polymorphism mutations in the BnGRP1 sequence, 10 haplotypes (Hap) were formed. Compared with the other types, the cultivar BnGRP1 Hap1 in the panel demonstrated the longest root length and heaviest root weight. BnGRP1 Hap1 overexpression in rapeseed led to enhanced low-P tolerance. CRISPR/Cas9-derived BnGRP1 Hap4 knockout mutations in rapeseed can lead to sensitivity to low-P stress. Furthermore, BnGRP1 Hap1 influences the expression of the phosphate transporter 1 gene (PHT1) associated with P absorption. Overall, the findings of this study highlight new insights into the mechanisms of GRP1 enhancement of low-P tolerance in rapeseed. [ABSTRACT FROM AUTHOR]

Photoemission spectroscopy (PES) has been used widely to study the electronic structure of valence and core levels. However, conventional PES is surface-sensitive. To probe the interface and bulk properties of materials, hard X-ray photoemission spectroscopy (HXPES) has received increasing interest in the last decade, because of the deep probing ability of photoelectrons with higher kinetic energies (2-10 keV). Recently, a HXPES system was developed at the Canadian Light Source, using the high-energy version of a R4000 electron analyzer-based spectrometer connected to a medium-energy beamline, the soft X-ray microcharacterization beamline (SXRMB). Excellent performance of the beamline and the spectrometer is demonstrated herein using Au Fermi and 4f core lines; and the controlled probing depth of HXPES at SXRMB is demonstrated by tuning the photon energy (2-9 keV) in the study of a series of Si[O.sub.2]/SiC multilayer samples. Combined with the high-resolution X-ray absorption spectroscopy available at the SXRMB, the HXPES offers a powerful nondestructive technique for studying bulk properties of various materials. Key words: XPS, medium energy beamline, bulk property, interface structure, HXPES. La spectroscopie de photoemission (XPS) a ete largement utilisee pour etudier les structures electroniques des couches de valence et de coeur. Toutefois, la spectroscopie XPS classique est dependante de la surface. Afin de permettre l'exploration des proprietes internes et d'interface des materiaux, la spectroscopie de photoemission induite par les rayons X durs (HXPES ou hard X-ray photoemission spectroscopy) a suscite un interet grandissant au cours de la derniere decennie, en raison de la plus grande capacite penetrante qu'offrent les photoelectrons de haute energie cinetique (de 2 a10 keV). Recemment, le Centre canadien de rayonnement synchrotron a mis au point un appareil HXPES, en utilisant un spectrometre constitue d'un analyseur d'electrons de modele R4000 en version a haute energie connecte a une source de rayonnement d'energie intermediaire, soit la source de rayonnement Soft X-Ray Microcharacterization (SXRMB) [rayonnement synchrotron X mou pour la microcaracterisation des materiaux]. En etudiant une serie d'echantillons multicouches de SiO2/SiC, nous faisons ici la demonstration des excellentes performances de la source de rayonnement et du spectrometre, grace a l'etude des bandes du niveau de Fermi et de la couche de coeur 4f de l'or (Au), ainsi que la demonstration de la profondeur de sondage reglable du spectrometre HXPES de la SXRMB, grace au reglage de l'energie des photons (de 2 a 9 keV). Couplee a la spectroscopie d'absorption des rayons X a haute resolution rendue possible par la SXRMB, la spectroscopie HXPES constitue une technique non destructive puissante pour l'etude des proprietes internes de divers materiaux. [Traduit par la Redaction] Mots-cles : XPS, source de rayonnement d'energie intermediaire, proprietes internes, structure d'interface, HXPES., Introduction Photoemission spectroscopy (PES) is a versatile and powerful technique for studying the electronic structure of matter by measuring the kinetic energies of photoelectrons ejected upon the irradiation of atoms [...]

The evidential variable shows the powerful ability on the parameter description, so we have cooperated it with the linear Wiener process to model linear degradation processes. However, the degradation paths of some products exhibit two‐phase patterns over the running time, which cannot be modeled by the linear Wiener process. Hence, it is developed into an associated evidential variable‐based two‐phase Wiener process. In order to utilize the proposed model, the related evidence obtaining, evidence fusion and performance inference approaches are constructed. A simulation study and an actual case are performed to verify the superiorities of the proposed method. The proposed method provides higher accuracies of the useful life, degradation, and reliability evaluations, due to utilizing the evidential variable and considering the two‐phase degradation conditions. [ABSTRACT FROM AUTHOR]