664 research outputs found

    Growth of High Quality SiGe alloy layers using UTA-Si buffer layers (研究員報告)

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    Effect of Temperature on the Corrosion Behaviours of L360QCS in the Environments Containing Elemental Sulphur and H₂S/CO₂

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    The effect of temperature on the corrosion behaviours of L360QCS in H₂S, CO₂ and elemental sulphur environments are investigated. The corrosion weight-loss rate, microscopy, chemical compositions and phase compositions of corrosion products are studied by means of the weight-loss analysis, SEM and XRD techniques. As shown, the corrosion rate increased greatly with an increase of the temperature, and the corrosion scale is dropped off easily because of the weak adhesion force between the matrix and the corrosion products. The composition and structure analysed by energy-dispersive x-ray spectroscopy (EDS) and XRD show that the corrosion product scales are composed of cubic FeS and little tetragonal FeS.Исследовано влияние температуры на режимы коррозии L360QCS в атмосферах H₂S, CO₂ и атомарной серы. Скорость коррозии, измеряемая по потере веса, микроскопия, химический и фазовый состав продуктов коррозии определялись анализом потери веса, СЭМ и рентгеноструктурным анализом (РСА). Показано, что скорость коррозии сильно возрастает с температурой, и коррозионная окалина легко отпадает благодаря слабой силе адгезии между матрицей и продуктами коррозии. Исследования состава и структуры методами рентгеноспектрального электронно-зондового микроанализа и РСА показали, что окалины продуктов реакции состоят из кубического FeS и небольшой части тетрагонального FeS.Досліджено вплив температури на режими корозії L360QCS в атмосфері H₂S, CO₂ та атомарної сірки. Швидкість корозії, яка вимірюється за втратами ваги, мікроскопія, хемічний та фазовий склад продуктів корозії визначалися аналізою втрати ваги, СЕМ та рентґеноструктурною аналізою (РСА). Показано, що швидкість корозії сильно збільшується з температурою, і корозійна жужелиця легко відпадає через слабку силу адгезії між матрицею та продуктами корозії. Дослідження складу та структури методами рентґеноспектральної електронно-зондової мікроаналізи та РСА показали, що жужелиці продуктів реакції складаються з кубічного FeS та незначної частки тетрагонального FeS

    An H{\alpha} Impression of Ly{\alpha} Galaxies at z6z\simeq6 with Deep JWST/NIRCam Imaging

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    We present a study of seven spectroscopically confirmed Ly{\alpha} emitting galaxies at redshift z6z\simeq6 using the James Webb Space Telescope (JWST) NIRCam images. These galaxies, with a wide range of Ly{\alpha} luminosities, were recently observed in a series of NIRCam broad- and medium-bands. We measure the continuum and H{\alpha} line properties of the galaxies using the combination of the NIRCam photometry and archival Hubble Space Telescope imaging data. We find that galaxies with bluer UV continuum slopes likely have higher escape fractions of Ly{\alpha} photons. We also find that galaxies with higher Ly{\alpha} line emission tend to produce ionizing photons more efficiently. The most Ly{\alpha}-luminous galaxy in the sample has a high ionizing photon production efficiency of log10ξion,0_{10} \xi_{\rm ion, 0} (Hz erg1^{-1}) > 26. Our results support that Ly{\alpha} galaxies may have served as an important contributor to the cosmic reionization. Blue and bright Ly{\alpha} galaxies are also excellent targets for JWST follow-up spectroscopic observations.Comment: 10 pages, 4 figures, 2 tables, submitted to ApJ

    M^2-3DLaneNet: Multi-Modal 3D Lane Detection

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    Estimating accurate lane lines in 3D space remains challenging due to their sparse and slim nature. In this work, we propose the M^2-3DLaneNet, a Multi-Modal framework for effective 3D lane detection. Aiming at integrating complementary information from multi-sensors, M^2-3DLaneNet first extracts multi-modal features with modal-specific backbones, then fuses them in a unified Bird's-Eye View (BEV) space. Specifically, our method consists of two core components. 1) To achieve accurate 2D-3D mapping, we propose the top-down BEV generation. Within it, a Line-Restricted Deform-Attention (LRDA) module is utilized to effectively enhance image features in a top-down manner, fully capturing the slenderness features of lanes. After that, it casts the 2D pyramidal features into 3D space using depth-aware lifting and generates BEV features through pillarization. 2) We further propose the bottom-up BEV fusion, which aggregates multi-modal features through multi-scale cascaded attention, integrating complementary information from camera and LiDAR sensors. Sufficient experiments demonstrate the effectiveness of M^2-3DLaneNet, which outperforms previous state-of-the-art methods by a large margin, i.e., 12.1% F1-score improvement on OpenLane dataset

    3D Molecular Generation via Virtual Dynamics

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    Structure-based drug design, i.e., finding molecules with high affinities to the target protein pocket, is one of the most critical tasks in drug discovery. Traditional solutions, like virtual screening, require exhaustively searching on a large molecular database, which are inefficient and cannot return novel molecules beyond the database. The pocket-based 3D molecular generation model, i.e., directly generating a molecule with a 3D structure and binding position in the pocket, is a new promising way to address this issue. Herein, we propose VD-Gen, a novel pocket-based 3D molecular generation pipeline. VD-Gen consists of several carefully designed stages to generate fine-grained 3D molecules with binding positions in the pocket cavity end-to-end. Rather than directly generating or sampling atoms with 3D positions in the pocket like in early attempts, in VD-Gen, we first randomly initialize many virtual particles in the pocket; then iteratively move these virtual particles, making the distribution of virtual particles approximate the distribution of molecular atoms. After virtual particles are stabilized in 3D space, we extract a 3D molecule from them. Finally, we further refine atoms in the extracted molecule by iterative movement again, to get a high-quality 3D molecule, and predict a confidence score for it. Extensive experiment results on pocket-based molecular generation demonstrate that VD-Gen can generate novel 3D molecules to fill the target pocket cavity with high binding affinities, significantly outperforming previous baselines

    Positive selection for the male functionality of a co-retroposed gene in the hominoids

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    <p>Abstract</p> <p>Background</p> <p>New genes generated by retroposition are widespread in humans and other mammalian species. Usually, this process copies a single parental gene and inserts it into a distant genomic location. However, retroposition of two adjacent parental genes, <it>i.e</it>. co-retroposition, had not been reported until the hominoid chimeric gene, <it>PIPSL</it>, was identified recently. It was shown how two genes linked in tandem (phosphatidylinositol-4-phosphate 5-kinase, type I, alpha, <it>PIP5K1A </it>and proteasome 26S subunit, non-ATPase, 4, <it>PSMD4</it>) could be co-retroposed from a single RNA molecule to form this novel chimeric gene. However, understanding of the origination and biological function of <it>PIPSL </it>requires determination of the coding potential of this gene as well as the evolutionary forces acting on its hominoid copies.</p> <p>Results</p> <p>We tackled these problems by analyzing the evolutionary signature in both within-species variation and between species divergence in the sequence and structure of the gene. We revealed a significant evolutionary signature: the coding region has significantly lower sequence variation, especially insertions and deletions, suggesting that the human copy may encode a protein. Moreover, a survey across five different hominoid species revealed that all adaptive changes of <it>PSMD4</it>-derived regions occurred on branches leading to human and chimp rather than other hominoid lineages. Finally, computational analysis suggests testis-specific transcription of <it>PIPSL </it>is regulated by tissue-dependent methylation rather than some transcriptional leakage.</p> <p>Conclusion</p> <p>Therefore, this set of analyses showed that <it>PIPSL </it>is an extraordinary co-retroposed protein-coding gene that may participate in the male functions of humans and its close relatives.</p

    Viral Infection Induces Expression of Novel Phased MicroRNAs from Conserved Cellular MicroRNA Precursors

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    RNA silencing, mediated by small RNAs including microRNAs (miRNAs) and small interfering RNAs (siRNAs), is a potent antiviral or antibacterial mechanism, besides regulating normal cellular gene expression critical for development and physiology. To gain insights into host small RNA metabolism under infections by different viruses, we used Solexa/Illumina deep sequencing to characterize the small RNA profiles of rice plants infected by two distinct viruses, Rice dwarf virus (RDV, dsRNA virus) and Rice stripe virus (RSV, a negative sense and ambisense RNA virus), respectively, as compared with those from non-infected plants. Our analyses showed that RSV infection enhanced the accumulation of some rice miRNA*s, but not their corresponding miRNAs, as well as accumulation of phased siRNAs from a particular precursor. Furthermore, RSV infection also induced the expression of novel miRNAs in a phased pattern from several conserved miRNA precursors. In comparison, no such changes in host small RNA expression was observed in RDV-infected rice plants. Significantly RSV infection elevated the expression levels of selective OsDCLs and OsAGOs, whereas RDV infection only affected the expression of certain OsRDRs. Our results provide a comparative analysis, via deep sequencing, of changes in the small RNA profiles and in the genes of RNA silencing machinery induced by different viruses in a natural and economically important crop host plant. They uncover new mechanisms and complexity of virus-host interactions that may have important implications for further studies on the evolution of cellular small RNA biogenesis that impact pathogen infection, pathogenesis, as well as organismal development
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