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Showing papers by "University of Science and Technology of China published in 2012"


Journal ArticleDOI
Georges Aad1, T. Abajyan2, Brad Abbott3, Jalal Abdallah4  +2964 moreInstitutions (200)
TL;DR: In this article, a search for the Standard Model Higgs boson in proton-proton collisions with the ATLAS detector at the LHC is presented, which has a significance of 5.9 standard deviations, corresponding to a background fluctuation probability of 1.7×10−9.

9,282 citations


Journal ArticleDOI
TL;DR: These guidelines are presented for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes.
Abstract: In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.

4,316 citations


Journal ArticleDOI
27 Jan 2012-Science
TL;DR: Submicrometer-thick membranes made from graphene oxide can be completely impermeable to liquids, vapors, and gases, including helium, but these membranes allow unimpeded permeation of water (H2O permeates through the membranes at least 1010 times faster than He).
Abstract: Permeation through nanometer pores is important in the design of materials for filtration and separation techniques and because of unusual fundamental behavior arising at the molecular scale. We found that submicrometer-thick membranes made from graphene oxide can be completely impermeable to liquids, vapors, and gases, including helium, but these membranes allow unimpeded permeation of water (H 2 O permeates through the membranes at least 10 10 times faster than He). We attribute these seemingly incompatible observations to a low-friction flow of a monolayer of water through two-dimensional capillaries formed by closely spaced graphene sheets. Diffusion of other molecules is blocked by reversible narrowing of the capillaries in low humidity and/or by their clogging with water.

2,602 citations


Journal ArticleDOI
F. P. An, J. Z. Bai, A. B. Balantekin1, H. R. Band1  +271 moreInstitutions (34)
TL;DR: The Daya Bay Reactor Neutrino Experiment has measured a nonzero value for the neutrino mixing angle θ(13) with a significance of 5.2 standard deviations.
Abstract: The Daya Bay Reactor Neutrino Experiment has measured a nonzero value for the neutrino mixing angle θ13 with a significance of 5.2 standard deviations. Antineutrinos from six 2.9 GW_(th) reactors were detected in six antineutrino detectors deployed in two near (flux-weighted baseline 470 m and 576 m) and one far (1648 m) underground experimental halls. With a 43 000 ton–GW_(th)–day live-time exposure in 55 days, 10 416 (80 376) electron-antineutrino candidates were detected at the far hall (near halls). The ratio of the observed to expected number of antineutrinos at the far hall is R=0.940± 0.011(stat.)±0.004(syst.). A rate-only analysis finds sin^22θ_(13)=0.092±0.016(stat.)±0.005(syst.) in a three-neutrino framework.

2,163 citations


Journal ArticleDOI
TL;DR: In this paper, a review of the lithium ion battery hazards, thermal runaway theory, basic reactions, thermal models, simulations and experimental works is presented, and the related prevention techniques are summarized and discussed on the inherent safety methods and safety device methods.

1,825 citations


Journal ArticleDOI
16 Jul 2012-ACS Nano
TL;DR: This work presents a high-capacity supercapacitor material based on the nitrogen-doped porous carbon nan ofibers synthesized by carbonization of macroscopic-scale carbonaceous nanofibers coated with polypyrrole (CNFs@polypyr role) at an appropriate temperature.
Abstract: Supercapacitors (also known as ultracapacitors) are considered to be the most promising approach to meet the pressing requirements of energy storage. Supercapacitive electrode materials, which are closely related to the high-efficiency storage of energy, have provoked more interest. Herein, we present a high-capacity supercapacitor material based on the nitrogen-doped porous carbon nanofibers synthesized by carbonization of macroscopic-scale carbonaceous nanofibers (CNFs) coated with polypyrrole (CNFs@polypyrrole) at an appropriate temperature. The composite nanofibers exhibit a reversible specific capacitance of 202.0 F g–1 at the current density of 1.0 A g–1 in 6.0 mol L–1 aqueous KOH electrolyte, meanwhile maintaining a high-class capacitance retention capability and a maximum power density of 89.57 kW kg–1. This kind of nitrogen-doped carbon nanofiber represents an alternative promising candidate for an efficient electrode material for supercapacitors.

1,522 citations


Proceedings Article
03 Dec 2012
TL;DR: A novel approach to low-level vision problems that combines sparse coding and deep networks pre-trained with denoising auto-encoder (DA) is presented and can automatically remove complex patterns like superimposed text from an image, rather than simple patterns like pixels missing at random.
Abstract: We present a novel approach to low-level vision problems that combines sparse coding and deep networks pre-trained with denoising auto-encoder (DA). We propose an alternative training scheme that successfully adapts DA, originally designed for unsupervised feature learning, to the tasks of image denoising and blind inpainting. Our method's performance in the image denoising task is comparable to that of KSVD which is a widely used sparse coding technique. More importantly, in blind image inpainting task, the proposed method provides solutions to some complex problems that have not been tackled before. Specifically, we can automatically remove complex patterns like superimposed text from an image, rather than simple patterns like pixels missing at random. Moreover, the proposed method does not need the information regarding the region that requires inpainting to be given a priori. Experimental results demonstrate the effectiveness of the proposed method in the tasks of image denoising and blind inpainting. We also show that our new training scheme for DA is more effective and can improve the performance of unsupervised feature learning.

1,389 citations


Journal ArticleDOI
TL;DR: A review of the progress in photonic quantum information processing can be found in this article, where the emphasis is given to the creation of photonic entanglement of various forms, tests of the completeness of quantum mechanics (in particular, violations of local realism), quantum information protocols for quantum communication, and quantum computation with linear optics.
Abstract: Multiphoton interference reveals strictly nonclassical phenomena. Its applications range from fundamental tests of quantum mechanics to photonic quantum information processing, where a significant fraction of key experiments achieved so far comes from multiphoton state manipulation. The progress, both theoretical and experimental, of this rapidly advancing research is reviewed. The emphasis is given to the creation of photonic entanglement of various forms, tests of the completeness of quantum mechanics (in particular, violations of local realism), quantum information protocols for quantum communication (e.g., quantum teleportation, entanglement purification, and quantum repeater), and quantum computation with linear optics. The scope of the review is limited to ``few-photon'' phenomena involving measurements of discrete observables.

1,156 citations


Journal ArticleDOI
13 Feb 2012-ACS Nano
TL;DR: The method presented here is proved to be versatile to induce macroscopic assembly of reduced graphene sheets with other functional metal oxides and thus to access a variety of graphene-based multifunctional nanocomposites in the form of macroscopy hydrogels or aerogels.
Abstract: We report a one-step fabrication of macroscopic multifunctional graphene-based hydrogels with robust interconnected networks under the synergistic effects of the reduction of graphene oxide sheets by ferrous ions and in situ simultaneous deposition of nanoparticles on graphene sheets. The functional components, such as α-FeOOH nanorods and magnetic Fe3O4 nanoparticles, can be easily incorporated with graphene sheets to assemble macroscopic graphene monoliths just by control of pH value under mild conditions. Such functional graphene-based hydrogels exhibit excellent capability for removal of pollutants and, thus, could be used as promising adsorbents for water purification. The method presented here is proved to be versatile to induce macroscopic assembly of reduced graphene sheets with other functional metal oxides and thus to access a variety of graphene-based multifunctional nanocomposites in the form of macroscopic hydrogels or aerogels.

1,029 citations


Journal ArticleDOI
TL;DR: The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) as discussed by the authors is a special reflecting Schmidt telescope with an innovative active reflecting Schmidt configuration which continuously changes the mirror's surface that adjusts during the observation process and combines thin deformable mirror active optics with segmented active optics.
Abstract: The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST, also called the Guo Shou Jing Telescope) is a special reflecting Schmidt telescope. LAMOST's special design allows both a large aperture (effective aperture of 3.6 m–4.9 m) and a wide field of view (FOV) (5°). It has an innovative active reflecting Schmidt configuration which continuously changes the mirror's surface that adjusts during the observation process and combines thin deformable mirror active optics with segmented active optics. Its primary mirror (6.67 m × 6.05 m) and active Schmidt mirror (5.74m × 4.40m) are both segmented, and composed of 37 and 24 hexagonal sub-mirrors respectively. By using a parallel controllable fiber positioning technique, the focal surface of 1.75 m in diameter can accommodate 4000 optical fibers. Also, LAMOST has 16 spectrographs with 32 CCD cameras. LAMOST will be the telescope with the highest rate of spectral acquisition. As a national large scientific project, the LAMOST project was formally proposed in 1996, and approved by the Chinese government in 1997. The construction started in 2001, was completed in 2008 and passed the official acceptance in June 2009. The LAMOST pilot survey was started in October 2011 and the spectroscopic survey will launch in September 2012. Up to now, LAMOST has released more than 480000 spectra of objects. LAMOST will make an important contribution to the study of the large-scale structure of the Universe, structure and evolution of the Galaxy, and cross-identification of multi-waveband properties in celestial objects.

966 citations


Journal ArticleDOI
TL;DR: Simulations on four real networks show that the proposed semi-local centrality measure can well identify influential nodes and is a tradeoff between the low-relevant degree centrality and other time-consuming measures.
Abstract: Identifying influential nodes that lead to faster and wider spreading in complex networks is of theoretical and practical significance. The degree centrality method is very simple but of little relevance. Global metrics such as betweenness centrality and closeness centrality can better identify influential nodes, but are incapable to be applied in large-scale networks due to the computational complexity. In order to design an effective ranking method, we proposed a semi-local centrality measure as a tradeoff between the low-relevant degree centrality and other time-consuming measures. We use the Susceptible–Infected–Recovered (SIR) model to evaluate the performance by using the spreading rate and the number of infected nodes. Simulations on four real networks show that our method can well identify influential nodes.

Journal ArticleDOI
TL;DR: These free-standing thin films provide a route to simplify the electrode-manufacturing process by eliminating conducting additives and binders and are the highest values achieved while simultaneously maintaining excellent specific capacitances and energy densities for graphene materials.
Abstract: We present a novel method to prepare highly conductive, free-standing, and flexible porous carbon thin films by chemical activation of reduced graphene oxide paper. These flexible carbon thin films possess a very high specific surface area of 2400 m2 g–1 with a high in-plane electrical conductivity of 5880 S m–1. This is the highest specific surface area for a free-standing carbon film reported to date. A two-electrode supercapacitor using these carbon films as electrodes demonstrated an excellent high-frequency response, an extremely low equivalent series resistance on the order of 0.1 ohm, and a high-power delivery of about 500 kW kg–1. While higher frequency and power values for graphene materials have been reported, these are the highest values achieved while simultaneously maintaining excellent specific capacitances and energy densities of 120 F g–1 and 26 W h kg–1, respectively. In addition, these free-standing thin films provide a route to simplify the electrode-manufacturing process by eliminating...

Journal ArticleDOI
TL;DR: LAMOST (Large sky Area Multi-Object fiber Spectroscopic Telescope) is a Chinese national scientific research facility operated by National Astronomical Observatories, Chinese Academy of Sciences (NAOC) as mentioned in this paper.
Abstract: LAMOST (Large sky Area Multi-Object fiber Spectroscopic Telescope) is a Chinese national scientific research facility operated by National Astronomical Observatories, Chinese Academy of Sciences (NAOC). After two years of commissioning beginning in 2009, the telescope, instruments, software systems and operations are nearly ready to begin the main science survey. Through a spectral survey of millions of objects in much of the northern sky, LAMOST will enable research in a number of contemporary cutting edge topics in astrophysics, such as discovery of the first generation stars in the Galaxy, pinning down the formation and evolution history of galaxies — especially the Milky Way and its central massive black hole, and looking for signatures of the distribution of dark matter and possible sub-structures in the Milky Way halo. To maximize the scientific potential of the facility, wide national participation and international collaboration have been emphasized. The survey has two major components: the LAMOST ExtraGAlactic Survey (LEGAS) and the LAMOST Experiment for Galactic Understanding and Exploration (LEGUE). Until LAMOST reaches its full capability, the LEGUE portion of the survey will use the available observing time, starting in 2012. An overview of the LAMOST project and the survey that will be carried out in the next five to six years is presented in this paper. The science plan for the whole LEGUE survey, instrumental specifications, site conditions, and the descriptions of the current on-going pilot survey, including its footprints and target selection algorithm, will be presented as separate papers in this volume.

Journal ArticleDOI
TL;DR: The efficiency of second harmonic generation shows a dramatic even-odd oscillation with the number of layers, consistent with the presence (absence) of inversion symmetry in even-layer (odd-layer) and the giant spin-valley coupling which fully suppresses interlayer hopping at valence band edge near K points.
Abstract: Motivated by the triumph and limitation of graphene for electronic applications, atomically thin layers of group VI transition metal dichalcogenides are attracting extensive interest as a class of graphene-like semiconductors with a desired band-gap in the visible frequency range. The monolayers feature a valence band spin splitting with opposite sign in the two valleys located at corners of 1st Brillouin zone. This spin-valley coupling, particularly pronounced in tungsten dichalcogenides, can benefit potential spintronics and valleytronics with the important consequences of spin-valley interplay and the suppression of spin and valley relaxations. Here we report the first optical studies of WS2 and WSe2 monolayers and multilayers. The efficiency of second harmonic generation shows a dramatic even-odd oscillation with the number of layers, consistent with the presence (absence) of inversion symmetry in even-layer (odd-layer). Photoluminescence (PL) measurements show the crossover from an indirect band gap semiconductor at mutilayers to a direct-gap one at monolayers. The PL spectra and first-principle calculations consistently reveal a spin-valley coupling of 0.4 eV which suppresses interlayer hopping and manifests as a thickness independent splitting pattern at valence band edge near K points. This giant spin-valley coupling, together with the valley dependent physical properties, may lead to rich possibilities for manipulating spin and valley degrees of freedom in these atomically thin 2D materials.

Journal ArticleDOI
TL;DR: The majority of currently used PTT agents are inorganic nanomaterials, which usually are not biodegradable and may remain inside the body for long periods of time after systemic administration, but the use of organic nanoparticles, such as porphysome and light-absorbing conductive polymers, as PTT agent has thus attracted attention recently.
Abstract: Kai Yang , Huan Xu , Liang Cheng , Chunyang Sun , Jun Wang , and Zhuang Liu * IO N Photothermal therapy (PTT) that uses optical absorbing agents to “cook” cancer under light irradiation has attracted signifi cant attention in recent years as a promising alternative or supplement to traditional cancer therapies. [ 1–3 ] Numerous reports have shown encouraging therapeutic effects of PTT in many preclinical animal experiments, using various light absorbing nanomaterials as PTT agents. [ 1–21 ] Ideal PTT agents should exhibit strong absorbance in the near-infrared (NIR) region, which is a transparency window for biological tissues, and could effi ciently transfer the absorbed NIR optical energy into heat. The biocompatibility of PTT agents is another primary concern. The tumor-homing ability of PTT agents is also important for photothermal treatment of cancer upon systemic administration. Gold nanomaterials including nanorods, nanocages, nanoshells, and composite nanostructures are likely the mostwidely explored class of PTT nanoagents. [ 4–8 , 19 , 20 ] A number of other inorganic nanomaterials, such as carbon nanomaterials [ 9–13 , 17 , 18 , 21 ] (e.g., carbon nanotubes, nanographene), Pd nanosheets, copper sulfi de and copper selenide nanoparticles, have also shown potential in PTT cancer treatment. [ 14–16 ] However, the majority of currently used PTT agents are inorganic nanomaterials, which usually are not biodegradable and may remain inside the body for long periods of time after systemic administration. The use of organic nanoparticles, such as porphysome and light-absorbing conductive polymers, as PTT agents, has thus attracted signifi cant attention recently. [ 22–24 ]

Journal ArticleDOI
20 Jul 2012-ACS Nano
TL;DR: From an extensive structural search using the first-principles particle-swarm optimization (PSO) global algorithm, two boron monolayers (α(1)- and β(1-sheet) are predicted to be the most stable α- and β-types of borons sheets, respectively.
Abstract: Boron, a nearest-neighbor of carbon, is possibly the second element that can possess free-standing flat monolayer structures, evidenced by recent successful synthesis of single-walled and multiwalled boron nanotubes (MWBNTs). From an extensive structural search using the first-principles particle-swarm optimization (PSO) global algorithm, two boron monolayers (α1- and β1-sheet) are predicted to be the most stable α- and β-types of boron sheets, respectively. Both boron sheets possess greater cohesive energies than the state-of-the-art two-dimensional boron structures (by more than 60 meV/atom based on density functional theory calculation using PBE0 hybrid functional), that is, the α-sheet previously predicted by Tang and Ismail-Beigi and the g1/8- and g2/15-sheets (both belonging to the β-type) recently reported by Yakobson and co-workers. Moreover, the PBE0 calculation predicts that the α-sheet is a semiconductor, while the α1-, β1-, g1/8-, and g2/15-sheets are all metals. When two α1 monolayers are sta...

Journal ArticleDOI
TL;DR: A novel Mn(3)O(4)/CoSe(2) hybrid which could be a promising candidate for OER catalysts and shows good stability in 0.1 M KOH electrolyte, which is highly required to a promising OER electrocatalyst.
Abstract: The design of efficient, cheap, and abundant oxygen evolution reaction (OER) catalysts is crucial to the development of sustainable energy sources for powering fuel cells. We describe here a novel Mn3O4/CoSe2 hybrid which could be a promising candidate for such electrocatalysts. Possibly due to the synergetic chemical coupling effects between Mn3O4 and CoSe2, the constructed hybrid displayed superior OER catalytic performance relative to its parent CoSe2/DETA nanobelts. Notably, such earth-abundant cobalt (Co)-based catalyst afforded a current density of 10 mA cm–2 at a small overpotential of ∼0.45 V and a small Tafel slope down to 49 mV/decade, comparable to the best performance of the well-investigated cobalt oxides. Moreover, this Mn3O4/CoSe2 hybrid shows good stability in 0.1 M KOH electrolyte, which is highly required to a promising OER electrocatalyst.

Journal ArticleDOI
TL;DR: In this paper, the bending and free vibration analyses of thin-to-moderately thick composite plates reinforced by single-walled carbon nanotubes using the finite element method based on the first order shear deformation plate theory are presented.

Journal ArticleDOI
TL;DR: A new class of monolithic hydrogels/aerogels consisting of highly uniform carbonaceous nanofibers (CNFs), based on the recent, well-developed templatedirected hydrothermal carbonization (HTC) process is reported.
Abstract: Hydrogels and aerogels are two typical families of gels, classified according to the medium they encompass, that is, water and air, respectively. Hydrogels have not only pervaded our everyday life in a variety of forms (e.g., fruit jellies, toothpaste, contact lenses, and hair gel), but have also been extensively explored as functional soft materials for use in various scientific fields. Replacing the liquid solvent in hydrogels or other wet gels by air without collapsing the network structure can lead to a new type of porous materials, namely, aerogels. Particularly, 3D nanoscale networks with open pores in the gels allow access and fast diffusion of ions and molecules, and thus hydrogels/aerogels have exhibited excellent performance as super adsorbents, electrode materials for batteries and supercapacitors, catalyst supports, and chemical and biological sensors. Despite their outstanding potential, several challenges in aerogel synthesis still must be addressed prior to their extensive practical application. The major problem associated with conventional aerogels is poor mechanical stability. The mechanical strength of aerogels could be enhanced by nanocasting conformal polymer coatings on preformed 3D networks, but this was accompanied by dramatic decreases in their porosity. Furthermore, to prevent the network from collapsing in a gel, supercritical drying is the most widely used technique for solvent removal. It is difficult to prepare low-cost aerogels on a large scale due to the limitations of industrial supercritical drying. Although several nanomaterials including carbon nanotubes, cellulose nanofibers, and the newly discovered graphene have been recently used as building blocks and assembled into monolithic gels, there is a lack of precise control of their physicochemical properties, particularly the size of building blocks, the porosity, and their surface chemistry, which are crucial in the further design and functionalization of aerogels for various applications. Here we report a new class of monolithic hydrogels/aerogels consisting of highly uniform carbonaceous nanofibers (CNFs), based on the recent, well-developed templatedirected hydrothermal carbonization (HTC) process. Compared with the conventional process for aerogel preparation, our synthetic method has some significant advantages: 1) Direct scaleup from 30 mL to 12 L just by using a large autoclave and without changing reactant concentrations and reaction time; 2) Easy and precise control of the structural parameters and mechanical strength of the CNF hydrogels/ aerogels over a wide range; and 3) Extraordinary flexibility and high chemical reactivity of the CNF gels give them great application potential. The synthesis of CNF gels is illustrated in Figure 1a. Ultrathin Te nanowire (TeNWs) templates are first dispersed in glucose solution to form a homogenous mixture (step 1 in Figure 1a). Hydrothermal treatment of the mixture at 180 8C for 12–48 h results in a mechanically robust monolithic gel-like product, which occupies the whole Teflon container and can be taken out directly without any damage (step 2 in Figure 1a; see also Supporting Information Figure S1a). The as-prepared wet gel can be easily cut into the desired shape (Supporting Information Figure S1b). After washing and chemical etching to remove TeNWs (Supporting Information Figure S2), the CNF hydrogel is formed (step 3 in Figure 1a). To obtain the CNF aerogel, water in the hydrogel is removed by freeze-drying (step 4 in Figure 1a and Supporting Information Figure S1c). A low-magnification SEM image of the aerogel reveals a highly porous network structure consisting of disordered nanofibers with uniform size (Figure 1c, left). There is no apparent difference in CNF size and distribution over the whole monolithic gel (Supporting Information Figure S3), that is, the network structure is homogeneous. Further SEM observations indicate that these highly uniform nanofibers interconnect with each other to a high degree through numerous junctions (Figure 1c, right). We hypothesize that these junctions are responsible for the outstanding mechanical properties of the gels. Formation of junctions between CNFs is not difficult to understand. In the original mixture before hydrothermal treatment, it was unavoidable that the TeNWs physically contacted or approached each other if their concentration reached a critical [*] Dr. H. W. Liang, Q. F. Guan, L. F. Chen, Z. Zhu, W. J. Zhang, Prof. S. H. Yu Division of Nanomaterials and Chemistry, Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemistry, National Synchrotron Radiation Laboratory, University of Science and Technology of China Hefei, Anhui 230026 (China) E-mail: shyu@ustc.edu.cn Homepage: http://staff.ustc.edu.cn/~ yulab/

Journal ArticleDOI
TL;DR: Recent developments concerning enzyme-responsive polymeric assemblies, nanoparticles, and hydrogels are described by highlighting this research area with selected literature reports.
Abstract: Being responsive and adaptive to external stimuli is an intrinsic feature characteristic of all living organisms and soft matter. Specifically, responsive polymers can exhibit reversible or irreversible changes in chemical structures and/or physical properties in response to a specific signal input such as pH, temperature, ionic strength, light irradiation, mechanical force, electric and magnetic fields, and analyte of interest (e.g., ions, bioactive molecules, etc.) or an integration of them. The past decade has evidenced tremendous growth in the fundamental research of responsive polymers, and accordingly, diverse applications in fields ranging from drug or gene nanocarriers, imaging, diagnostics, smart actuators, adaptive coatings, to self-healing materials have been explored and suggested. Among a variety of external stimuli that have been utilized for the design of novel responsive polymers, enzymes have recently emerged to be a promising triggering motif. Enzyme-catalyzed reactions are highly selective and efficient toward specific substrates under mild conditions. They are involved in all biological and metabolic processes, serving as the prime protagonists in the chemistry of living organisms at a molecular level. The integration of enzyme-catalyzed reactions with responsive polymers can further broaden the design flexibility and scope of applications by endowing the latter with enhanced triggering specificity and selectivity. In this tutorial review, we describe recent developments concerning enzyme-responsive polymeric assemblies, nanoparticles, and hydrogels by highlighting this research area with selected literature reports. Three different types of systems, namely, enzyme-triggered self-assembly and aggregation of synthetic polymers, enzyme-driven disintegration and structural reorganization of polymeric assemblies and nanoparticles, and enzyme-triggered sol-to-gel and gel-to-sol transitions, are described. Their promising applications in drug controlled release, biocatalysis, imaging, sensing, and diagnostics are also discussed.

Journal ArticleDOI
Georges Aad1, Brad Abbott2, Jalal Abdallah3, S. Abdel Khalek  +3081 moreInstitutions (197)
TL;DR: A combined search for the Standard Model Higgs boson with the ATLAS experiment at the LHC using datasets corresponding to integrated luminosities from 1.04 fb(-1) to 4.9 fb(1) of pp collisions is described in this paper.

Journal ArticleDOI
TL;DR: In this paper, a review of the lithium ion battery hazards, thermal runaway theory, basic reactions, thermal models, simulations and experimental works is presented, and the related prevention techniques are summarized and discussed on the inherent safety methods and safety device methods.
Abstract: Lithium ion battery and its safety are taken more consideration with fossil energy consuming and the reduction requirement of CO2 emission. The safety problem of lithium ion battery is mainly contributed by thermal runaway caused fire and explosion. This paper reviews the lithium ion battery hazards, thermal runaway theory, basic reactions, thermal models, simulations and experimental works firstly. The general theory is proposed and detailed reactions are summarized, which include solid electrolyte interface decomposition, negative active material and electrolyte reaction, positive active material and electrolyte reaction, electrolyte decomposition, negative active material and binder reaction, and so on. The thermal models or electrochemical-thermal models include one, two and three dimensional models, which can be simulated by finite element method and finite volume method. And then the related prevention techniques are simply summarized and discussed on the inherent safety methods and safety device methods. Some perspectives and outlooks on safety enhancement for lithium ion battery are proposed for the future development. Language: en

Journal ArticleDOI
TL;DR: A synergistic photocatalysis mechanism between ZnO and g-C(3)N(4)-ZnO composite possesses excellent long-term stability for a photocatalytic reaction in aqueous solutions, according to the photodegradation results.
Abstract: The g-C3N4–ZnO composite photocatalysts with various weight percents of ZnO were synthsized by a simple calcination process The photocatalysts were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), UV-vis diffuse reflection spectroscopy (UV-vis), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) The PXRD and HR-TEM results show that the composite materials consist of hexagonal wurzite phase ZnO and g-C3N4 The solid-state UV-vis diffuse reflection spectra show that the absorption edge of the composite materials shifts toward the lower energy region and to longer wavelengths in comparison with pure ZnO and g-C3N4 Remarkably, the photocatalytic activity of g-C3N4–ZnO composites has been demonstrated, via photodegradation of Methyl Orange (MO) and p-nitrophenol experiments The photocatalytic activity of g-C3N4–ZnO for photodegradation of Methyl Orange and p-nitrophenol under visible light irradiation was increased by over 3 and 6 times, respectively, to be much higher than that of single-phase g-C3N4, clearly demonstrating a synergistic effect between ZnO and g-C3N4 The concentrations of Zn2+ in g-C3N4–ZnO system after a photocatalytic reaction at various reaction times were found to be much lower than those for a ZnO system under the same reaction conditions, indicating that the g-C3N4–ZnO composite possesses excellent long-term stability for a photocatalytic reaction in aqueous solutions Furthermore, a synergistic photocatalysis mechanism between ZnO and g-C3N4 was proposed based on the photodegradation results Such obviously improved performance of g-C3N4–ZnO can be ascribed mainly to the enhancement of electron–hole separations at the interface of ZnO and g-C3N4


Book ChapterDOI
07 Oct 2012
TL;DR: This paper presents the Least Squares Regression (LSR) method for subspace segmentation, which takes advantage of data correlation, which is common in real data and significantly outperforms state-of-the-art methods.
Abstract: This paper studies the subspace segmentation problem which aims to segment data drawn from a union of multiple linear subspaces. Recent works by using sparse representation, low rank representation and their extensions attract much attention. If the subspaces from which the data drawn are independent or orthogonal, they are able to obtain a block diagonal affinity matrix, which usually leads to a correct segmentation. The main differences among them are their objective functions. We theoretically show that if the objective function satisfies some conditions, and the data are sufficiently drawn from independent subspaces, the obtained affinity matrix is always block diagonal. Furthermore, the data sampling can be insufficient if the subspaces are orthogonal. Some existing methods are all special cases. Then we present the Least Squares Regression (LSR) method for subspace segmentation. It takes advantage of data correlation, which is common in real data. LSR encourages a grouping effect which tends to group highly correlated data together. Experimental results on the Hopkins 155 database and Extended Yale Database B show that our method significantly outperforms state-of-the-art methods. Beyond segmentation accuracy, all experiments demonstrate that LSR is much more efficient.

Journal ArticleDOI
TL;DR: It is demonstrated how shape selectivity and optimized surface composition result in exceptional oxygen reduction activity of octahedral PtNi nanoparticles (NPs) by utilizing a facile, completely surfactant-free solvothermal synthesis.
Abstract: We demonstrate how shape selectivity and optimized surface composition result in exceptional oxygen reduction activity of octahedral PtNi nanoparticles (NPs). The alloy octahedra were obtained by utilizing a facile, completely surfactant-free solvothermal synthesis. We show that the choice of precursor ligands controls the shape, while the reaction time tunes the surface Pt:Ni composition. The 9.5 nm sized PtNi octahedra reached a 10-fold surface area-specific (∼3.14 mA/cmPt2) as well as an unprecedented 10-fold Pt mass based (∼1.45 A/mgPt) activity gain over the state-of-art Pt electrocatalyst, approaching the theoretically predicted limits.

Journal ArticleDOI
Georges Aad, B. Abbott1, Jalal Abdallah2, A. A. Abdelalim3  +3013 moreInstitutions (174)
TL;DR: In this article, detailed measurements of the electron performance of the ATLAS detector at the LHC were reported, using decays of the Z, W and J/psi particles.
Abstract: Detailed measurements of the electron performance of the ATLAS detector at the LHC are reported, using decays of the Z, W and J/psi particles. Data collected in 2010 at root s = 7 TeV are used, corresponding to an integrated luminosity of almost 40 pb(-1). The inter-alignment of the inner detector and the electromagnetic calorimeter, the determination of the electron energy scale and resolution, and the performance in terms of response uniformity and linearity are discussed. The electron identification, reconstruction and trigger efficiencies, as well as the charge misidentification probability, are also presented.

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TL;DR: The results show that the alkali treated bio-char possesses larger surface area than those of raw and acid treated Bio-char, and accordingly exhibits a more excellent adsorption performance than the other two bio-chars and other adsorbents reported previously.

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A.E. Bondar1, A. Garmash1, R. Mizuk, D. Santel2  +154 moreInstitutions (46)
TL;DR: The observation of two narrow structures in the mass spectra of the π(±)Υ(nS) and π (±)h(b)(mP) pairs that are produced in association with a single charged pion in Υ(5S) decays is reported.
Abstract: We report the observation of two narrow structures in the mass spectra of the pi(+/-) Y(nS) (n = 1, 2, 3) and pi(+/-) h(b)(mP) (m = 1, 2) pairs that are produced in association with a single charged pion in Y(5S) decays The measured masses and widths of the two structures averaged over the five final states are M-1 = (10 6072 +/- 20) MeV/c(2), Gamma(1) =(184 +/- 24) MeV, and M-2 = (10 6522 +/- 15) MeV/c(2), Gamma(2) = (115 +/- 22) MeV The results are obtained with a 1214 fb(-1) data sample collected with the Belle detector in the vicinity of the Y(5S) resonance at the KEKB asymmetric-energy e(+)e(-) collider

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TL;DR: A National Science Foundation of China (NSFC) major research project, Destruction of the North China Craton (NCC), has been carried out in the past few years by Chinese scientists through an in-depth and systematic observations, experiments and theoretical analyses, with an emphasis on the spatio-temporal distribution of the NCC destruction, the structure of deep earth and shallow geological records of the craton evolution, the mechanism and dynamics of craton destruction.
Abstract: A National Science Foundation of China (NSFC) major research project, Destruction of the North China Craton (NCC), has been carried out in the past few years by Chinese scientists through an in-depth and systematic observations, experiments and theoretical analyses, with an emphasis on the spatio-temporal distribution of the NCC destruction, the structure of deep earth and shallow geological records of the craton evolution, the mechanism and dynamics of the craton destruction. From this work the following conclusions can be drawn: (1) Significant spatial heterogeneity exists in the NCC lithospheric thickness and crustal structure, which constrains the scope of the NCC destruction. (2) The nature of the Paleozoic, Mesozoic and Cenozoic sub-continental lithospheric mantle (CLM) underneath the NCC is characterized in detail. In terms of water content, the late Mesozoic CLM was rich in water, but Cenozoic CLM was highly water deficient. (3) The correlation between magmatism and surface geological response confirms that the geological and tectonic evolution is governed by cratonic destruction processes. (4) Pacific subduction is the main dynamic factor that triggered the destruction of the NCC, which highlights the role of cratonic destruction in plate tectonics.