207 research outputs found

    ARPES insights on the metallic states of YbB6(001): E(k) dispersion, temporal changes and spatial variation

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    We report high resolution Angle Resolved PhotoElectron Spectroscopy (ARPES) results on the (001) cleavage surface of YbB6_{6}, a rare-earth compound which has been recently predicted to host surface electronic states with topological character. We observe two types of well-resolved metallic states, whose Fermi contours encircle the time-reversal invariant momenta of the YbB6_{6}(001) surface Brillouin zone, and whose full (E,kk)-dispersion relation can be measured wholly unmasked by states from the rest of the electronic structure. Although the two-dimensional character of these metallic states is confirmed by their lack of out-of-plane dispersion, two new aspects are revealed in these experiments. Firstly, these states do not resemble two branches of opposite, linear velocity that cross at a Dirac point, but rather straightforward parabolas which terminate to high binding energy with a clear band bottom. Secondly, these states are sensitive to time-dependent changes of the YbB6_{6} surface under ultrahigh vacuum conditions. Adding the fact that these data from cleaved YbB6_{6} surfaces also display spatial variations in the electronic structure, it appears there is little in common between the theoretical expectations for an idealized YbB6_{6}(001) crystal truncation on the one hand, and these ARPES data from real cleavage surfaces on the other.Comment: 8 pages, 4 figures (accepted in Physical Review B

    Molecular Conformation Generation via Shifting Scores

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    Molecular conformation generation, a critical aspect of computational chemistry, involves producing the three-dimensional conformer geometry for a given molecule. Generating molecular conformation via diffusion requires learning to reverse a noising process. Diffusion on inter-atomic distances instead of conformation preserves SE(3)-equivalence and shows superior performance compared to alternative techniques, whereas related generative modelings are predominantly based upon heuristical assumptions. In response to this, we propose a novel molecular conformation generation approach driven by the observation that the disintegration of a molecule can be viewed as casting increasing force fields to its composing atoms, such that the distribution of the change of inter-atomic distance shifts from Gaussian to Maxwell-Boltzmann distribution. The corresponding generative modeling ensures a feasible inter-atomic distance geometry and exhibits time reversibility. Experimental results on molecular datasets demonstrate the advantages of the proposed shifting distribution compared to the state-of-the-art.Comment: 18 pages, 7 figure

    Prognostics of Lithium-Ion Batteries Based on Wavelet Denoising and DE-RVM

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    Lithium-ion batteries are widely used in many electronic systems. Therefore, it is significantly important to estimate the lithium-ion battery’s remaining useful life (RUL), yet very difficult. One important reason is that the measured battery capacity data are often subject to the different levels of noise pollution. In this paper, a novel battery capacity prognostics approach is presented to estimate the RUL of lithium-ion batteries. Wavelet denoising is performed with different thresholds in order to weaken the strong noise and remove the weak noise. Relevance vector machine (RVM) improved by differential evolution (DE) algorithm is utilized to estimate the battery RUL based on the denoised data. An experiment including battery 5 capacity prognostics case and battery 18 capacity prognostics case is conducted and validated that the proposed approach can predict the trend of battery capacity trajectory closely and estimate the battery RUL accurately

    Tunable optical limiting optofluidic device filled with graphene oxide dispersion in ethanol

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    An optofluidic device with tunable optical limiting property is proposed and demonstrated. The optofluidic device is designed for adjusting the concentration of graphene oxide (GO) in the ethanol solution and fabricated by photolithography technique. By controlling the flow rate ratio of the injection, the concentration of GO can be precisely adjusted so that the optical nonlinearity can be changed. The nonlinear optical properties and dynamic excitation relaxation of the GO/ethanol solution are investigated by using Z-scan and pump-probe measurements in the femtosecond regime within the 1.5 μm telecom band. The GO/ethanol solution presents ultrafast recovery time. Besides, the optical limiting property is in proportion to the concentration of the solution. Thus, the threshold power and the saturated power of the optical limiting property can be simply and efficiently manipulated by controlling the flow rate ratio of the injection. Furthermore, the amplitude regeneration is demonstrated by employing the proposed optofluidic device. The signal quality of intensity-impaired femtosecond pulse is significantly improved. The optofluidic device is compact and has long interaction length of optical field and nonlinear material. Heat can be dissipated in the solution and nonlinear material is isolated from other optical components, efficiently avoiding thermal damage and mechanical damage

    A fuzzy neural network based dynamic data allocation model on heterogeneous multi-GPUs for large-scale computations

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    The parallel computation capabilities of modern GPU (Graphics Processing Unit) processors have attracted increasing attention from researchers and engineers who have been conducting high computational throughput studies. However, current single GPU based engineering solutions are often struggle to fulfill their real-time requirements. Thus, the multi-GPU-based approach has become a popular and cost-effective choice for tackling the demands. In those cases, the computational load balancing over multiple GPU “nodes” is often the key and bottleneck that affect the quality and performance of the runtime system. The existing load balancing approaches are mainly based on the assumption that all GPU nodes in the same computer framework are of equal computational performance, which are often not the case due to cluster design and other legacy issues. This paper presents a novel dynamic load balancing (DLB) model for rapid data division and allocation on heterogeneous GPU nodes based on an innovative fuzzy neural network (FNN). In this research, a 5-state parameter feedback mechanism defining the overall cluster and node performances is proposed. The corresponding FNN-based DLB model will be capable of monitoring and predicting individual node performance under different workload scenarios. A real-time adaptive scheduler has been devised to reorganize the data inputs to each node when necessary to maintain their runtime computational performances. The devised model has been implemented on two dimensional (2D) discrete wavelet transform (DWT) tasks for evaluation. Experiment results show that this DLB model has enabled a high computational throughput while ensuring real-time and precision requirements from complex computational tasks

    Iridium(III) complex-based activatable probe for phosphorescent/time-gated luminescent sensing and imaging of cysteine in mitochondria of live cells and animals

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    This study reports an activatable iridium(III) complex probe for phosphorescence/time-gated luminescence detection of cysteine (Cys) in vitro and in vivo. The probe, [Ir(ppy)2(NTY-bpy)](PF6), is developed by incorporating a strong electron withdrawing group, nitroolefin, into a bipyridine ligand of the Ir(III) complex. The luminescence of the probe is quenched due to the intramolecular charge transfer (ICT) process, but switched on by a specific recognition reaction between the probe and Cys. [Ir(ppy)2(NTY-bpy)](PF6) shows high sensitivity and selectivity for Cys detection and good biocompatibility. The long-lived emission of [Ir(ppy)2(NTY-bpy)](PF6) allows time-gated luminescence analysis of Cys in cells and human sera. These properties make it convenient for the phosphorescence and time-gated luminescence imaging and flow cytometry analysis of Cys in live samples. The Cys images in cancer cells and inflamed macrophage cells reveal that [Ir(ppy)2(NTY-bpy)](PF6) is distributed in mitochondria after cellular internalization. Visualizations and flow cytometry analysis of mitochondrial Cys levels and Cys-mediated redox activities of live cells are achieved. Using [Ir(ppy)2(NTY-bpy)](PF6) as a probe, in vivo sensing and imaging of Cys in D. magna, zebrafish, and mice are then demonstrated

    Iridium(III) complex-based activatable probe for phosphorescent/time-gated luminescent sensing and imaging of cysteine in mitochondria of live cells and animals

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    This study reports an activatable iridium(III) complex probe for phosphorescence/time-gated luminescence detection of cysteine (Cys) in vitro and in vivo. The probe, [Ir(ppy)2(NTY-bpy)](PF6), is developed by incorporating a strong electron withdrawing group, nitroolefin, into a bipyridine ligand of the Ir(III) complex. The luminescence of the probe is quenched due to the intramolecular charge transfer (ICT) process, but switched on by a specific recognition reaction between the probe and Cys. [Ir(ppy)2(NTY-bpy)](PF6) shows high sensitivity and selectivity for Cys detection and good biocompatibility. The long-lived emission of [Ir(ppy)2(NTY-bpy)](PF6) allows time-gated luminescence analysis of Cys in cells and human sera. These properties make it convenient for the phosphorescence and time-gated luminescence imaging and flow cytometry analysis of Cys in live samples. The Cys images in cancer cells and inflamed macrophage cells reveal that [Ir(ppy)2(NTY-bpy)](PF6) is distributed in mitochondria after cellular internalization. Visualizations and flow cytometry analysis of mitochondrial Cys levels and Cys-mediated redox activities of live cells are achieved. Using [Ir(ppy)2(NTY-bpy)](PF6) as a probe, in vivo sensing and imaging of Cys in D. magna, zebrafish, and mice are then demonstrated

    Intratumoral Delivery of a PD-1-blocking scFv encoded in Oncolytic HSV-1 Promotes Antitumor Immunity and Synergizes with TIGIT Blockade

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    恶性肿瘤已严重威胁人类健康和生命,现有的治疗手段远远未能满足临床需求。厦门大学研究团队联合浙江养生堂生物科技有限公司、养生堂有限公司进行协同攻关,研制出新一代肿瘤免疫治疗药物——“注射用重组人PD-1抗体单纯疱疹病毒”。研究发现,重组表达PD-1单链抗体的溶瘤病毒具有“双药合一”抗肿瘤的突出优势,提高肿瘤治愈率。相关成果于2020年3月3日以研究论文形式在线发表于Cancer Immunology Research(《癌症免疫学研究》)期刊,为指导新型溶瘤病毒的升级改造和突破肿瘤免疫耐受提供了新的思路,为重组表达PD-1单链抗体的溶瘤病毒药物运用于肿瘤临床治疗奠定了坚实的理论基础。 厦门大学公共卫生学院夏宁邵教授和黄承浩助理教授为该论文的共同通讯作者,博士生林超龙和任文峰为该论文的共同第一作者。【Abstract】Oncolytic virotherapy can lead to systemic antitumor immunity, but the therapeutic potential of oncolytic viruses (OVs) in humans is limited due to their insufficient ability to overcome the immunosuppressive tumor microenvironment (TME). Here, we showed that locoregional oncolytic virotherapy upregulated the expression of PD-L1 in the TME, which was mediated by virus-induced type I and type II interferons (IFNs). To explore PD-1/PD-L1 signaling as a direct target in tumor tissue, we developed a novel immunotherapeutic herpes simplex virus (HSV), OVH-aMPD-1, that expressed a single-chain variable fragment (scFv) against PD-1 (aMPD-1 scFv). The virus was designed to locally deliver aMPD-1 scFv in the TME to achieve enhanced antitumor effects. This virus effectively modified the TME by releasing damage associated molecular patterns (DAMPs), promoting antigen cross-presentation by dendritic cells, and enhancing the infiltration of activated T cells; these alterations resulted antitumor T cell activity which led to reduced tumor burdens in a liver cancer model. Compared with OVH, OVH-aMPD-1 promoted the infiltration of myeloid-derived suppressor cells (MDSCs),resulting in significantly higher percentages of CD155+ G-MDSCs and M-MDSCs in tumors. In combination with TIGIT blockade, this virus enhanced tumor-specific immune responses in mice with implanted subcutaneous tumors or invasive tumors. These findings highlighted that intratumoral immunomodulation with an OV expressing aMPD-1 scFv could be an effective standalone strategy to treat cancers or drive maximal efficacy of a combination therapy with other immune checkpoint inhibitors.This work was supported by grant 2018ZX10301404-001-002 from the National Science and Technology Major Project and grant 81571990 from the National Natural Science Foundation of China.该研究获得了国家自然科学基金、国家科技重大专项的资助

    Coupling Efficiency Measurements for Long-pulsed Solid Sodium Laser Based on Measured Sodium Profile Data

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    In 2013, a serial sky test has been held on 1.8 meter telescope in Yunnan observation site after 2011-2012 Laser guide star photon return test. In this test, the long-pulsed sodium laser and the launch telescope have been upgraded, a smaller and brighter beacon has been observed. During the test, a sodium column density lidar and atmospheric coherence length measurement equipment were working at the same time. The coupling efficiency test result with the sky test layout, data processing, sodium beacon spot size analysis, sodium profile data will be presented in this paper
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