Low‐dimensional luminescent lead halide perovskites have attracted tremendous attention for their fascinating optoelectronic properties, while the toxicity of lead is still considered a drawback. ...Herein, we report a novel lead‐free zero‐dimensional (0D) indium‐based perovskite (Cs2InBr5⋅H2O) single crystal that is red‐luminescent with a high photoluminescence quantum yield (PLQY) of 33 %. Experimental and computational studies reveal that the strong PL emission might originate from self‐trapping excitons (STEs) that result from an excited‐state structural deformation. More importantly, the in situ transformation between hydrated Cs2InBr5⋅H2O and the dehydrated form is accompanied with a switchable dual emission, which enables it to act as a PL water‐sensor in humidity detection or the detection of traces of water in organic solvents.
Unleaded and unleashed: A highly emissive lead‐free indium‐based perovskite single crystal, Cs2InBr5⋅H2O, was successfully prepared. The versatile material is the first reversible metal halide perovskite photoluminescence water sensor and paves the way for the application of metal halide perovskites in water detection.
Low‐dimensional lead halide perovskite materials recently have drawn much attention owing to the intriguing broadband emissions; however, the toxicity of lead will hinder their future development. ...Now, a lead‐free (C4H14N2)2In2Br10 single crystal with a unique zero‐dimensional (0D) structure constituted by InBr63− octahedral and InBr4− tetrahedral units is described. The single crystal exhibits broadband photoluminescence (PL) that spans almost the whole visible spectrum with a lifetime of 3.2 μs. Computational and experimental studies unveil that an excited‐state structural distortion in InBr63− octahedral units enables the formation of intrinsic self‐trapped excitons (STEs) and thus contributing the broad emission. Furthermore, femtosecond transient absorption (fs‐TA) measurement reveals that the ultrafast STEs formation together with an efficient intersystem crossing has made a significant contribution to the long‐lived and broad STE‐based emission behavior.
A lead‐free indium‐based (C4H14N2)2In2Br10 single crystal was synthesized and characterized; it has a unique 0D crystal structure. An intrinsic self‐trapped exciton‐based ultra‐broad photoluminescence has been observed as a result of an excited‐state structural distortion in InBr63− octahedrons.
A novel Z-scheme system of CeO2–Ag/AgBr heterostructure photocatalyst exhibits excellent ability to eliminate ciprofloxacin under visible light irradiation.
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•Novel Z-scheme ...CeO2–Ag/AgBr photocatalysts were prepared.•Superior photocatalytic activity for the degradation of ciprofloxacin (CIP) refractory pollutants was obtained.•The factors affecting the photocatalytic performance were investigated.•A plausible degradation pathway for CIP was proposed.•A Z-scheme photocatalytic mechanism was proposed.
In this study, CeO2–Ag/AgBr composite photocatalysts with a Z-scheme configuration were fabricated by in situ interspersal of AgBr on CeO2 and subsequent photoreduction process. The CeO2–Ag/AgBr composites exhibited enhanced photocatalytic activity for the photodegradation of ciprofloxacin (CIP) under visible light irradiation. The effects of initial CIP concentration and various inorganic salts were investigated in detail. Three-dimensional excitation–emission matrix fluorescence spectra were used to further monitor the CIP molecule degradation. Plausible degradation pathways for CIP were proposed based on LC-MS instruments. Photoluminescence, electrochemical impedance spectroscopy, and photocurrent tests indicated the rapid transfer and migration of electrons–holes can be achieved in this ternary photocatalytic system. The enhanced photocatalytic performances of CeO2–Ag/AgBr could be credited to the accelerated interfacial charge transfer process and the improved separation of the photogenerated electron–hole pairs. The existence of a small amount of metallic Ag is conducive to the formation of a stable Z-scheme photocatalytic system. This work would pave the route for the design of novel Z-scheme photocatalytic systems for application in solar-to-fuel conversion and photocatalytic water treatment.
Learning Race from Face: A Survey Fu, Siyao; He, Haibo; Hou, Zeng-Guang
IEEE transactions on pattern analysis and machine intelligence,
12/2014, Letnik:
36, Številka:
12
Journal Article
Recenzirano
Faces convey a wealth of social signals, including race, expression, identity, age and gender, all of which have attracted increasing attention from multi-disciplinary research, such as psychology, ...neuroscience, computer science, to name a few. Gleaned from recent advances in computer vision, computer graphics, and machine learning, computational intelligence based racial face analysis has been particularly popular due to its significant potential and broader impacts in extensive real-world applications, such as security and defense, surveillance, human computer interface (HCI), biometric-based identification, among others. These studies raise an important question: How implicit, non-declarative racial category can be conceptually modeled and quantitatively inferred from the face? Nevertheless, race classification is challenging due to its ambiguity and complexity depending on context and criteria. To address this challenge, recently, significant efforts have been reported toward race detection and categorization in the community. This survey provides a comprehensive and critical review of the state-of-the-art advances in face-race perception, principles, algorithms, and applications. We first discuss race perception problem formulation and motivation, while highlighting the conceptual potentials of racial face processing. Next, taxonomy of feature representational models, algorithms, performance and racial databases are presented with systematic discussions within the unified learning scenario. Finally, in order to stimulate future research in this field, we also highlight the major opportunities and challenges, as well as potentially important cross-cutting themes and research directions for the issue of learning race from face.
Piezoelectric actuators (PEAs) have been widely used in nanotechnology due to their characteristics of fast response, large mass ratio, and high stiffness. However, hysteresis, which is an inherent ...nonlinear property of PEAs, greatly deteriorates the control performance of PEAs. In this paper, a nonlinear model predictive control (NMPC) approach is proposed for the displacement tracking problem of PEAs. First, a "nonlinear autoregressive-moving-average with exogenous inputs" (NARMAX) model of PEAs is implemented by multilayer neural networks; second, the tracking control problem is converted into an optimization problem by the principle of NMPC, and then, it is solved by the Levenberg-Marquardt algorithm. The most distinguished feature of the proposed approach is that the inversion model of hysteresis is no longer a necessity, which avoids the inversion imprecision problem encountered in the widely used inversion-based control algorithms. To verify the effectiveness of the proposed modeling and control methods, experiments are made on a commercial PEA product (P-753.1CD, Physik Instrumente), and comparisons with some existing controllers and a commercial proportional-integral-derivative controller are conducted. Experimental results show that the proposed scheme has satisfactory modeling and control performance.
The mean square consensus of linear multi-agent systems with communication noises is studied in this note. Each agent is modeled by a continuous-time linear time-invariant dynamics and the fixed ...communication topology is described by a digraph. The proposed consensus protocol is composed of two parts: the agent's own state feedback and the relative states between agent and its neighbor agents. Due to the existence of communication noises, the relative states cannot be obtained accurately. To attenuate the noise effect, a time-varying gain vector a(t)K is applied to the inaccurate relative states. It is proved that: 1) if the communication topology has a spanning tree and every node has at least one parent node, then the proposed protocol can solve the mean square consensus problem if and only if a(t) satisfies ∫ 0 ∞ a(s)ds = ∞ and ∫ 0 ∞ a 2 (s)ds <; ∞; and all roots of the polynomial whose coefficients are the elements of vector K are in the left half complex plane; 2) if the communication topology has a spanning tree and there exists one node without any parent node, then the condition ∫ 0 ∞ a 2 (s)ds <; ∞ is only sufficient but not necessary; and 3) if the communication topology has no spanning tree, then the proposed protocol cannot solve the mean square consensus problem.
This note further studies the previously proposed consensus protocol for linear multi-agent systems with communication noises. Each agent is allowed to have its own time-varying gain to attenuate the ...effect of communication noises. Therefore, the common assumption that all agents have the same noise-attenuation gain is not necessary. It has been proved that if all noise-attenuation gains are infinitesimal of the same order, then the mean square leader-following consensus can be reached. Furthermore, the convergence rate of the multi-agent system has been investigated. If the noise-attenuation gains belong to a class of functions which are bounded above and below by t -β (β ∈ (0, 1)) asymptotically, then the second-moment of the relative state between each follower agent and the leader agent is characterized by a function bounded above by t -β asymptotically.
Currently, there is no effective treatment for Burkitt's lymphoma in patients aged above 60 years, and thus research on effective treatment options for Burkitt's lymphoma has been gaining increasing ...attention. Artesunate has been identified as a novel effective growth suppressor in Burkitt's lymphoma. Here, we utilized molecular biology, transcriptome analysis, and other techniques to study artesunate-induced death of the Burkitt's lymphoma cells DAUDI and CA-46, the effect of artesunate on gene expression in DAUDI and CA-46 cells, and the effect of artesunate-induced ATF4-CHOP-CHAC1 pathway on ferroptosis. We also studied the inhibitory effects and ferroptosis induction of artesunate on CA-46 cells in mouse xenografts. Results showed that artesunate induced ferroptosis in DAUDI and CA-46 cells, as evidenced by the protective effect of liproxstatin-1, ferrostatin-1, and desferoxamine, resulting in an endoplasmic reticulum stress response, activation of the ATF4-CHOP-CHAC1 pathway enhanced ferroptosis in DAUDI and CA-46 cells. A mouse-transplanted tumor model showed that artesunate can inhibit the proliferation and induce ferroptosis of CA-46 cells in vivo. This study provides a novel perspective for the development of drugs against different types of Burkitt's lymphomas.
•Artesunate induced the ferroptosis in Burkitt's Lymphomas, causing a significant endoplasmic reticulum stress response.•The activation of the ATF4-CHOP-CHAC1 pathway enhanced the ferroptosis of Burkitt's Lymphoma cells.•Artesunate could inhibit the proliferation and induce the ferroptosis of Burkitt's lymphoma in vivo.
Due to their extensive application in human and veterinary medicine, antibiotics have been found worldwide and studied as new pollutants in the aquatic environment. In order to remove such ...pollutants, adsorption and photocatalysis have attracted tremendous attention because of their great potential in antibiotics removal from aqueous solutions. Graphene, as a novel two-dimensional nanomaterial, possesses unique structure and physicochemical properties, which can be used to efficiently adsorb and photodegrade antibiotics. This review provides an overview of the adsorptive and catalytic properties of graphene, and recent advances in adsorption and photodegradation of antibiotics by graphene and its derivatives. The factors that affect the adsorption and photodegradation of antibiotics are reviewed and discussed. Furthermore, the underlying mechanisms of adsorption and photodegradation are summarized and analyzed. Meanwhile, statistical analysis is conducted based on the number of papers and the maximum adsorption and photodegradation ability on various antibiotics removal. Finally, some unsolved problems together with major challenges that exist in the fabrication and application of graphene-based nanocomposites and the development for antibiotics removal is also proposed. This work provides theoretical guidance for subsequent research in the field of adsorption and photocatalytic removal of antibiotics from aqueous solution, especially on influence factors and mechanisms aspects.
•Recent studies on antibiotics removal from water by adsorption and photocatalysis.•Graphene and its derivatives as adsorbents and photocatalysts are reviewed.•Graphene properties and circumambient conditions influence the antibiotics removal.•The mechanisms of antibiotics removal via adsorption/photocatalysis are discussed.•Challenges and outlook are proposed to realize practical application.
The stochastic consensus problem of linear multi-input multi-output (MIMO) multi-agent systems (MASs) with communication noises and Markovian switching topologies is studied in this technical note. ...The agent's full state is first estimated by the state observer, and then the estimated state is exchanged with neighbor agents through a noisy communication environment. The communication topology is randomly switching and the switching law is described by a continuous-time Markovian chain. Then a consensus protocol is proposed for this MAS, and some sufficient conditions are obtained for ensuring the mean square and almost sure consensus. In addition, if the communication topology is fixed, some necessary and sufficient conditions for the mean square consensus can be obtained according to whether or not each agent in the system has parents.
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