41 research outputs found

    Cell transcriptomic atlas of the non-human primate Macaca fascicularis.

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    Studying tissue composition and function in non-human primates (NHPs) is crucial to understand the nature of our own species. Here we present a large-scale cell transcriptomic atlas that encompasses over 1 million cells from 45 tissues of the adult NHP Macaca fascicularis. This dataset provides a vast annotated resource to study a species phylogenetically close to humans. To demonstrate the utility of the atlas, we have reconstructed the cell-cell interaction networks that drive Wnt signalling across the body, mapped the distribution of receptors and co-receptors for viruses causing human infectious diseases, and intersected our data with human genetic disease orthologues to establish potential clinical associations. Our M. fascicularis cell atlas constitutes an essential reference for future studies in humans and NHPs.We thank W. Liu and L. Xu from the Huazhen Laboratory Animal Breeding Centre for helping in the collection of monkey tissues, D. Zhu and H. Li from the Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory) for technical help, G. Guo and H. Sun from Zhejiang University for providing HCL and MCA gene expression data matrices, G. Dong and C. Liu from BGI Research, and X. Zhang, P. Li and C. Qi from the Guangzhou Institutes of Biomedicine and Health for experimental advice or providing reagents. This work was supported by the Shenzhen Basic Research Project for Excellent Young Scholars (RCYX20200714114644191), Shenzhen Key Laboratory of Single-Cell Omics (ZDSYS20190902093613831), Shenzhen Bay Laboratory (SZBL2019062801012) and Guangdong Provincial Key Laboratory of Genome Read and Write (2017B030301011). In addition, L.L. was supported by the National Natural Science Foundation of China (31900466), Y. Hou was supported by the Natural Science Foundation of Guangdong Province (2018A030313379) and M.A.E. was supported by a Changbai Mountain Scholar award (419020201252), the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA16030502), a Chinese Academy of Sciences–Japan Society for the Promotion of Science joint research project (GJHZ2093), the National Natural Science Foundation of China (92068106, U20A2015) and the Guangdong Basic and Applied Basic Research Foundation (2021B1515120075). M.L. was supported by the National Key Research and Development Program of China (2021YFC2600200).S

    Etude de la théorie de Yang-Mills N=4

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    This thesis describes some of the developments in calculational techniques for scattering amplitudes in super-symmetric gauge field theory. The focus is on on-shell recursion relations and on the use of unitarity methods for loop calculations. In particular, on-shell recursion is related to the BCFW rules for computing tree-level gauge amplitudes. Combinations of unitarity cut techniques and recursion are used to compute the loop level amplitude. And finally start from amplitudes to obtain energy-energy correlation function in Super-Yang-Mills N = 4 Theory with the aid of Mellin-Barnes representation. In the last chapter, we were trying to find a convergent contour for the Mellin-Barnes integrals in multi-dimension obtained by looking for some approximation stationary-phase contour.Cette thèse décrit quelques développements dans les techniques de calcul des amplitudes de diffusion en théorie supersymétrique de champ de jauge . L'accent est mis sur les relations de récurrence on-shell et sur l'utilisation de méthodes d'unitarité pour des calculs de boucle. En particulier, la récurrence on-shell est liée aux règles BCFW pour calculer les amplitudes de jauge au niveau des arbres. Les combinaisons de techniques de coupe d'unitarité et la récurrence sont utilisées pour calculer les amplitudes de boucle, et finalement, à partir des amplitudes, pour obtenir la fonction de corrélation énergie-énergie en théorie de super-Yang-Mills N = 4 à l'aide de la représentation de Mellin-Barnes. Dans le dernier chapitre, nous tentons de trouver un contour convergent pour les intégrales de Mellin Barnes en multi-dimension obtenu par une certaine approximation d'un contour de phase stationnaire

    Etude de la théorie de Yang-Mills N=4

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    Cette thèse décrit quelques développements dans les techniques de calcul des amplitudes de diffusion en théorie supersymétrique de champ de jauge . L'accent est mis sur les relations de récurrence on-shell et sur l'utilisation de méthodes d'unitarité pour des calculs de boucle. En particulier, la récurrence on-shell est liée aux règles BCFW pour calculer les amplitudes de jauge au niveau des arbres. Les combinaisons de techniques de coupe d'unitarité et la récurrence sont utilisées pour calculer les amplitudes de boucle, et finalement, à partir des amplitudes, pour obtenir la fonction de corrélation énergie-énergie en théorie de super-Yang-Mills N = 4 à l'aide de la représentation de Mellin-Barnes. Dans le dernier chapitre, nous tentons de trouver un contour convergent pour les intégrales de Mellin Barnes en multi-dimension obtenu par une certaine approximation d'un contour de phase stationnairePARIS-BIUSJ-Biologie recherche (751052107) / SudocSudocFranceF

    Achieving Enhanced Sound Insulation through Micromembranes-Type Acoustic Metamaterials

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    Acoustic micromembranes (AμMs) are attracting more and more attention due to their unparalleled light weight but high sound transmission loss (STL) at low frequencies. Previous works showed that AμMs feature remarkable sound insulation compared to homogeneous plates with the same surface mass density, while some follow-up works claimed that the outstanding insulation capability of small AμMs samples disappears when the sample size grows. To uncover the working mechanisms underpinning the unique behavior of AμMs, in this paper, we present theoretical and numerical studies of AμMs that couple the vibrations of the supporting frame and the AμMs within the lattice. The results show how the global response in the STL of the AμMs assembly is related to the geometrical parameters of AμMs cells and the lattice. This study provides a theoretical foundation for designing a large-scale yet high-insulation assembly of AμMs, and paves the way for applying AμMs for blocking low-frequency noise

    Influence of wind speed and dust particle size on the corona characteristics of ± 1100 kV fitting models

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    Numerical analysis on space charge and AC-DC combined breakdown strength in polyethylene

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    In high voltage direct current (HVDC) power transmission systems, electrical equipment at the valve side usually withstands complex stresses like AC-DC combined voltages. Understanding the charge migration and accumulation characteristics under complex stresses and their influences on the breakdown strength are of great significance. This paper presents an in-depth simulation study on the AC-DC combined breakdown strength using a modified bipolar charge transport model, which takes the deterioration of materials into consideration. Firstly, the simulation results of charge profiles under AC voltages agree well with experimental results, which partly illustrates the appropriate selection of parameters. Then the AC breakdown strengths with different ramping rates and frequencies are studied. Charges accumulated relatively close to the surface of samples can cause severe distortion of the electric field after the change of voltage polarity. After that, the breakdown voltages with different ratios of the AC to DC component are calculated and analyzed, especially on how AC and DC component influence the charge migration and accumulation during the evolution of the aging process eventually leading to breakdown. The simulation results of AC-DC combined breakdown voltages show good agreement with previous experimental results

    Experimental and simulation study on space charge characteristics of epoxy resin filled with graphene oxide

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    Graphene has attracted much attention due to its advanced properties. In previous work, the relationship between temperature and the conductivity of epoxy-based nanocomposite filled with graphene oxide has been experimentally studied. To understand the charge transport behaviour, the space charge characteristics at different temperatures and field strengths are measured with an improved pulsed electroacoustic measurement system, which is designed for high-temperature space charge measurement. From the measurement results, epoxy resin (ER) filled with multi-layer graphene oxide (MGO/ER) shows suppressed charge migration while ER filled with single-layer graphene oxide (SGO/ER) shows a hetero charge accumulation, which is assumed to be caused by the partial reduction of graphene oxide to graphene. Compared to pure ER, the apparent mobility of the nanocomposites is smaller while the trap depth and number of trapped charges are larger, which is probably caused by the introduction of traps. In the simulation, the relationship between mobility, trap depth, trap density and charge distribution are firstly studied. Then the calculated values of mobility and trap depth are given to the parameters to compare the simulated charge profiles with experiment results. The simulation results agree well qualitatively with the experimental results, giving some support for the proposed explanations.</p

    An improved pulsed electroacoustic system for space charge measurements under high temperatures and arbitrary waveform voltages

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    This paper presents the design and calibration method of an improved pulsed electroacoustic (PEA) system for space charge measurements, including a novel nanosecond pulse generator and an improved electrode system, which can be used under various temperatures and arbitrary waveform voltages. The measurement principle of the PEA system is first analyzed, and the calibration method for the applied voltage is proposed to solve the problem of waveform distortion caused by voltages with different frequency components. For the pulse generator, the main parameters of output pulses are an amplitude of ∼700 V, a full width of 4.6 ns, a jitter of 0.24 ns, and a repetition rate of 10 kHz on the 50 Ω load. For the electrode system, the flexible upper electrode design is first introduced to achieve consistently close contact between the sample and the electrode. Besides, the hybrid heating method and the replaceable coupling capacitor and high voltage electrode head are adopted. Space charge measurements are conducted at different conditions using this PEA system, which includes different temperatures and different voltage waveforms. The experimental results verify the effectiveness of the calibration method and the feasibility of the improved PEA system

    Relaxation processes and conduction mechanism of epoxy resin filled with graphene oxide

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