165 research outputs found
Carbon-based antiviral nanomaterials: graphene, C-dots, and fullerenes. A perspective
The appearance of new and lethal viruses and their potential threat urgently requires innovative antiviral systems
2D Boron Nitride Heterostructures: Recent Advances and Future Challenges
Hexagonal boron nitride (hâBN) is one of the most attractive 2D materials because of its remarkable properties. Combining hâBN with other components (e.g., graphene, carbonitride, semiconductors) to form heterostructures opens new perspectives to developing advanced functional devices. In this review, the stateâofâtheâart in hâBN heterojunctions is highlighted. The preparation of highâquality 2D hâBN structures with fewer defects can maximize its intrinsic properties, such as thermal conductivity and electrical insulation, which are particularly important in 2D van der Waals electronics. On the other hand, the controlled introduction in 2D hâBN of multiple defects creates new properties and advanced functions. In this last case, only through a better understanding of the nature and function of defects, it is possible to develop advanced applications based on hâBN heterostructures. Engineering of the heterojunctions, such as the design of bonding at the interfaces, also plays a primary role. Several applications are proposed for hâBN heterostructures, mostly in sensing and photocatalysis, and some new perspectives worth further studies are opened. Finally, the current challenges and the rising opportunities for the future developments of nextâgeneration hâBN heterostructures are discussed
Hydroxylated boron nitride materials: from structures to functional applications
Abstract
Functionalization of boron nitride (BN) materials with hydroxyls has attracted great attention to accomplish better performances at micro- and nanoscale. BN surface hydroxylation, in fact, induces a change in properties and allows expanding the fields of application. In this review, we have summarized the state-of-the-art in developing hydroxylated bulk and nanoscale BN materials. The different synthesis routes to develop hydroxyl BN have been critically discussed. What emerges is the great variety of possible strategies to achieve BN hydroxylation, which, in turn, represents one of the most suitable methods to improve the solubility of BN nanomaterials. The improved stability of BN solutions creates conditions for producing high-quality nanocomposites. Furthermore, new interesting optical and electronic properties may arise from the functionalization by OH groups as displayed by a wide range of both theoretical and experimental studies. After the presentation of the most significant systems and methodologies, we question of future perspective and important trends of the next generation BN materials as well as the possible areas of advanced research.
Graphical abstract
Hydroxyl functionalization of boron nitride materials is a key method to control and enhance the properties and design new functional applications
Introduction: synchrotron radiation time resolved concurrent experimentsâa new Italian route to China
On November 11, 2010 in Shanghai qualified Chinese and Italian scientists met for the first Bilateral Italo/Chinese Workshop on Synchrotron Radiation Time Resolved Concurrent Experiments: Advantages and Future Applications. The workshop had been conceived to increase the scientific exchange between Italy and the P.R. China with the main goal to promote the development of new and unique methods of investigation by the means of synchrotron radiation. From its discovery in 1947 the development of synchrotron radiation sources and the growth of the related applications have been impressive and continuous all over the world, in particular in the major industrialized countries. In more than 50 years since its discovery, facilities around the world constantly evolved to provide beams in different forms, at different energies and with different properties for an incredible number of applications. Experimental researches based on this technology involve many academic disciplines and synchrotron radiation is nowadays an essential tool in many frontier disciplines. Because of its outstanding features, synchrotron radiation is a high-level multidisciplinary experimental platform that plays an essential role in many researches and technological applications, being universally acknowledged by the scientific community, the society as well as the governments. Actually, with more than 50 operational storage rings existing all over the world, laboratories based on synchrotron radiation sources are the most widely operated large-scale facilities with a total investment in the range of billions of dollars. Synchrotron radiation helped to push forward a huge number of researches that led to important discoveries. The reconstruction of the atomic structure of many proteins or of the local structure of high critical temperature superconductors may give just an idea of th
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IKNO, a user facility for coherent terahertz and UV synchrotron radiation
IKNO (Innovation and KNOwledge) is a proposal for a multi-user facility based
on an electron storage ring optimized for the generation of coherent
synchrotron radiation (CSR) in the terahertz frequency range, and of broadband
incoherent synchrotron radiation ranging from the IR to the VUV. IKNO can
be operated in an ultra-stable CSR mode with photon flux in the terahertz
frequency region up to nine orders of magnitude higher than in existing thirdgeneration
light sources. Simultaneously to the CSR operation, broadband
incoherent synchrotron radiation up to VUV frequencies is available at the
beamline ports. The main characteristics of the IKNO storage and its
performance in terms of CSR and incoherent synchrotron radiation are
described in this paper. The proposed location for the infrastructure facility is
Sardinia, Italy
Thermal Induced Polymerization of l-Lysine forms Branched Particles with Blue Fluorescence
AbstractThe polycondensation of amino acids can originate complex polymers that display fascinating structural and optical properties. Thermally induced amidation of lâlysine allows forming a branched polymer without the support of any catalyst. The polycondensation is completed at 240â250 °C; at higher temperatures, the amino acid degrades. The obtained polylysine particles have been studied by transmission electron microscopy (TEM), nuclear magnetic resonance, and infrared spectroscopy that allow for investigating the different steps of the synthesis. The resulting structure is characterized by peculiar optical properties, e.g., excitationâdependent blue fluorescence and good quantum efficiency. Hydrogen bonds and the interactions of the amino acids are considered responsible for the optical properties of both lâlysine monomer solutions at high concentrations and the branched nanopolymers
Foreword
The investment in space activities may be estimated in hundreds of billion of Euro and involves all G20 and BRIC countries. Why there is such a large interest, and why so many investments are allotted to space programs? Space is definitely an essential driver of economic growth. Aside from the obvious impact onto high-technology industry, many disciplines benefit from the development of space technologies. Climatology, environmental science, various medical sciences as well as telecommunication andâoff courseâmilitary applications are just few areas that need space technologies and justify the launch of satellites. Nearly a thousand satellites are currently in orbit with the aim of observing the Earth and are used for telecommunications, navigation and positioning in addition to specific scientific research and to space exploration, with missions funded by many space agencies. Man is exploring the solar system by means of satellites in orbit around Mars and Venus, and exploration is now active on the surface of Mars. China, India, Japan, Europe and United States launched spacecrafts in orbit around the Moon and the International Space Station is inhabited ever since 2003. More than 50 nations are participating in this ''colonization'' of space; they all benefit from space technologies and information gathered by satellites. Italy is participating since 1963 with a significant contribution to the activities of the International Space Station (ISS). The Chinese space program accounts for tens of launches with many satellites placed into orbit already. The successful mission of ShenzhouâX has confirmed China advances in space technologies and its ambitions for the future. In the next few years, China will launch its own Space Station, where many challenging scientific experiments in the fields of astronomy, microgravity, medicine and radiobiology will be performed. This contribution is the written, peer-reviewed version of a paper presented at the workshop ''Cosmic Rays and Radiobiology in a SinoItaly Network Strategy: First Bilateral Workshop COSMIC-RAD'' held at Institute of Modern Physics, Chinese Academic of Science, in Lanzhou, Gansu Province, China on September 3â4, 2012
Fulleropyrrolidine-functionalized ceria nanoparticles as a tethered dual nanosystem with improved antioxidant properties
Combining nanoceria and fulleropyrrolidine in a tethered nanosystem allows for efficient scavenging of reactive oxygen species and improved protection of mouse fibroblast cells exposed to a UV insult
graphene mediated surface enhanced raman scattering in silica mesoporous nanocomposite films
Highly performing mesoporous nanocomposite films with embedded exfoliated graphene and gold nanoparticles display a significant enhancement of G-SERS properties
Thermal-induced phase transitions in self-assembled mesostructured films studied by small-angle X-ray scattering
Two examples of phase transition in self-assembled mesostructured hybrid thin
films are reported. The materials have been synthesized using tetraethoxysilane
as the silica source hydrolyzed with or without the addition of methyltriethoxysilane.
The combined use of transmission electron microscopy, small-angle X-ray
scattering and computer simulation has been introduced to achieve a clear
identification of the organized phases. A structural study of the self-assembled
mesophases as a function of thermal treatment has allowed the overall phase
transition to be followed. The initial symmetries of mesophases in as-deposited
films have been linked to those observed in samples after thermal treatment.
The monodimensional shrinkage of silica films during calcination has induced a
phase transition from face-centered orthorhombic to body-centered cubic. In
hybrid films, instead, the phase transition has not involved a change in the unit
cell but a contraction of the cell parameter normal to the substrate
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