Facile synthesis and enhanced visible light photocatalytic activity of N and Zr co-doped TiO2 nanostructures from nanotubular titanic acid precursors

Zr/N co-doped TiO2 nanostructures were successfully synthesized using nanotubular titanic acid (NTA) as precursors by a facile wet chemical route and subsequent calcination. These Zr/N-doped TiO2 nanostructures made by NTA precursors show significantly enhanced visible light absorption and much higher photocatalytic performance than the Zr/N-doped P25 TiO2 nanoparticles. Impacts of Zr/N co-doping on the morphologies, optical properties, and photocatalytic activities of the NTA precursor-based TiO2 were thoroughly investigated. The origin of the enhanced visible light photocatalytic activity is discussed in detail.Comment: 8 pages, 7 figure

Enhancement of Visible-Light-Induced Photocurrent and Photocatalytic Activity of V and N Codoped TiO2 Nanotube Array Films

Highly ordered TiO2 nanotube arrays (TNAs) codoped with V and N were synthesized by electrochemical anodization in association with hydrothermal treatment. The samples were characterized by field emission scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The photocurrent and photocatalytic activity of codoped TiO2 nanotube arrays were investigated under visible light irradiation. Moreover, the production of hydroxyl radicals on the surface of visible light-irradiated samples is detected by a photoluminescence technique using terephthalic acid (TA) as a probe molecule. It was found that the V+N co-doped TiO2 nanotube arrays showed remarkably enhanced photocurrent and photocatalytic activity than undoped sample due to the V and N codoping.Comment: 15 Pages, 6 figure

Design graphique à l'ère de la Chine postmoderne

Comparing to the Chinese contemporary art which constantly prance at the head of the art market, the graphic design is an artistic object, industrial and popular, and modest in its cultural ambitions. However, its stakes present a scientific interest important because all of the specific design productions direct to the Chinese people than the foreigners. Subject to the economic and political partners, the graphic design, as the object of research, attest the existing conflicts not only inside the field of Chinese design, but also engaged in the full postmodern China. In the theoretical frame of the Cultural Studies, this thesis considers that the graphic design receives a significant social and political function in China, those stakes exceed its simple function of commercial communication which we are likely to think. From analysis of some historic and symbolic graphic productions, this research examines the updating of the Chinese cultural identity, in crisis today. In modern times, Maoist and postmodern periods, the graphic design has continued to participate in the dominant spirit of the times. As an active device, socio-forming the spirit and arising from the culture, the graphic design intervenes in the processes of individual and collective identity construction. After reported the reports sometimes ambiguous or uncertain, which were exercised by the hegemonic and competitive graphic models, this research attempts to decipher the current revealing tensions of the values and visions in the contradictory world.Comparé à l’art contemporain chinois qui ne cesse de caracoler en tête du marché de l’art, le design graphique est un objet artistique, industriel et populaire, modeste dans ses ambitions culturelles. Toutefois ses enjeux présentent un important intérêt scientifique dès lors que toutes les productions spécifiques du design s’adressent davantage au peuple chinois qu’aux étrangers. Soumis à des commanditaires économiques et politiques, le design graphique en tant qu’objet de recherche témoigne non seulement des luttes existant à l’intérieur du champ du design chinois mais également de celles qui se livrent en pleine Chine postmoderne. Dans le cadre théorique des Etudes Culturelles, cette thèse considère que le design graphique recèle une fonction sociale et politique significative en Chine, dont les enjeux excèdent ceux que l’on pense être susceptibles de répondre à une simple fonction de communication commerciale. A partir d’analyse de quelques productions graphiques emblématiques historiques, cette recherche s’interroge sur la réactualisation de l’identité culturelle chinoise, en crise aujourd’hui. Au cours des périodes moderne, maoïste et postmoderne, le design graphique n’a cessé de participer à l’esprit du temps dominant. En tant que dispositif actif, socio-formant l’esprit et relevant de la culture, le design graphique intervient dans les processus de construction identitaire individuelle et collective. Cette recherche, après avoir rendu compte des rapports parfois ambigus ou incertains, exercés par les modèles graphiques hégémoniques et concurrentiels, s’attache à décrypter les actuelles tensions révélatrices de valeurs et visions du monde contradictoires

Kinematical coherence between satellite galaxies and host stellar discs for MaNGA & SAMI galaxies

The effect of angular momentum on galaxy formation and evolution has been studied for several decades. Our recent two papers using IllustrisTNG-100 simulation have revealed the acquisition path of the angular momentum from large-scale environment (satellites within hundreds of kpc) through the circum-galactic medium (CGM) to the stellar discs, putting forward the co-rotation scenario across the three distance scales. In real observations, although the rotation signature for the CGM and environmental three-dimensional (3d) angular momentum are difficult to obtain, line-of-sight kinematics of group member galaxies and stellar disc kinematics of central galaxies are available utilizing existing group catalogue data and integral field unit (IFU) data. In this paper, we use (1) the group catalogue of SDSS DR7 and MaNGA IFU stellar kinematic maps and (2) the group catalogue of GAMA DR4 data and SAMI IFU stellar kinematic maps, to test if the prediction above can be seen in real data. We found the co-rotation pattern between stellar discs and satellites can be concluded with 99.7 percent confidence level ($\sim 3\sigma$) when combining the two datasets. And the random tests show that the signal can be scarcely drawn from random distribution.Comment: 8 pages, 8 figures, accepted for publication in MNRA

Unveiling the Secrets of Collaboration on Video-Sharing Platforms

In online video platforms, collaborative content creation gains popularity as vloggers exchange social capital to boost content’s appeal and personal visibility. However, existing research lacks rigorous verification of collaboration efficacy in this context. This study investigates the benefits of collaboration on vlogger influence within the online video domain. Utilizing a staggered difference-in-differences approach, we found that collaboration indeed generates positive impact on vloggers’ influence, as evidenced by the significant increases of their fan and like numbers among the audience. However, managing collaboration activities with suitable intensity is vital, as the marginal utility of collaborations diminishes with increased collaboration numbers. Furthermore, vloggers should avoid excessive non-core activities (e.g., uploading photo albums, audios, and articles) post-collaboration, as these peripheral activities negatively affect collaboration benefits in online video contexts. We believe that the findings of our study will provide helpful guidelines for designing more effective collaboration strategies on video sharing platforms

A Mixing-Accelerated Primal-Dual Proximal Algorithm for Distributed Nonconvex Optimization

In this paper, we develop a distributed mixing-accelerated primal-dual proximal algorithm, referred to as MAP-Pro, which enables nodes in multi-agent networks to cooperatively minimize the sum of their nonconvex, smooth local cost functions in a decentralized fashion. The proposed algorithm is constructed upon minimizing a computationally inexpensive augmented-Lagrangian-like function and incorporating a time-varying mixing polynomial to expedite information fusion across the network. The convergence results derived for MAP-Pro include a sublinear rate of convergence to a stationary solution and, under the Polyak-{\L}ojasiewics (P-{\L}) condition, a linear rate of convergence to the global optimal solution. Additionally, we may embed the well-noted Chebyshev acceleration scheme in MAP-Pro, which generates a specific sequence of mixing polynomials with given degrees and enhances the convergence performance based on MAP-Pro. Finally, we illustrate the competitive convergence speed and communication efficiency of MAP-Pro via a numerical example.Comment: 8 pages, 2 figures, accepted by ACC202