Day 1 :
University of Oxford, UK
Keynote: Understanding the structure of human dental tissues and their carious decay using advanced correlative microscopy
Time : 09:30-10:15
Alexander M Korsunsky leads MBLEM lab at the University of Oxford and the Centre for In situ processing science (CIPS) at Research Complex at Harwell. He consults Rolls-Royce plc on matters of residual stress and structural integrity and is Editor-in-Chief of Materials & Design, a major Elsevier journal.
Human dental tissues are hydrated biological mineral composites of hydroxyapatite crystallites within an organic matrix. Dentine and enamel have a hierarchical structure that delivers their versatile mechanical properties. These composites demonstrate superb thermo-mechanical stability, but suffer biological and chemical degradation (decay) due to one of the most widespread diseases, human dental caries, that arises as a consequence of modern sugar-rich diet and proceeds through the proliferation of acid-producing bacteria residing in the biofilm known as plaque. A strong and durable bond between dentine and enamel is formed by the dentine enamel junction (DEJ), an important biological interface that resists failure under long-term harsh thermal and mechanical conditions in the mouth. Understanding the underlying reasons for this remarkable combination of strength and toughness remains an important challenge, both in the context of dentistry and from the point of view of pursuing biomimetic advanced materials engineering. Residual strain develops in the vicinity of the DEJ during odontogenesis (tooth formation). The experimental and interpretational challenges that could not be overcome until recently presented an obstacle to the evaluation of residual stress in the vicinity of the DEJ at the appropriate spatial resolution. We used the recently developed FIB-DIC micro-ring-core method to determine the residual elastic strain at micron resolution. The residual strain profiling across the transition from dentine to enamel are correlated with the study of internal architecture using X-ray scattering (SAXS/WAXS). We illustrate how this provides improved insight into the origins of the remarkable performance of the DEJ. Further insights into dental erosion due to acid exposure will be provided.
University of Pardubice, Czech Republic
Time : 10:15-11:00
M Vlcek has completed his PhD from Institute of Chemical Technology, Pardubice, Czechoslovakia. Presently, he is the Professor and Director of Center of Materials and Nanotechnologies at University of Pardubice, Czech Republic. He was also a Visiting Professor at Lehigh University, USA. He has published more than 130 papers and his research focuses mainly on photoinduced structural changes in chalcogenide glasses and application of this phenomenon in fields as photonics, diffractive optics and high resolution lithography
Chalcogenide glasses (CHGs) possess unique properties, which make them very attractive materials for many applications, for many of them, their thin layers (TLs) are needed which are mainly fabricated by vacuum evaporation, sputtering or ablation methods. However, these methods need high vacuum equipment, which makes their fabrication expensive. Application of solution based deposition techniques would be cheaper and simpler. The purpose of this study is to find conditions to prepare by spin coating method thin layers of As and Ge based CHGs in optical quality which possess sensitivity to either UV light or electron beam which allows their micro and nano structuring either directly by exposure or consequently by wet/dry etching. It is shown that chemical processes occurring during the chalcogenide glass dissolution and TLs deposition by spin coating determine their structure and consequently their optical and chemical properties. Increasing of annealing temperature, we observed significant thermo-induced thickness decrease together with increase in refractive index and change in their chemical stability. Raman spectroscopy measurements confirmed that these changes are results of structural polymerization of TLs glass matrix and release of organic residuals. Optical quality of prepared thin layers was confirmed by UV-VIS-NIR, SEM and AFM methods. UV light and/or electron beam exposure resulted in structural changes and consequent change of their chemical stability. Both positive and negative type of selective etching was achieved even in TLs of the same composition depending on conditions of their treatment. Suitable conditions for fabrication of optical quality thin layers of As and Ge based CHGs by spin coating method were found. These layers are sensitive to UV and/or electron beam exposure. Application of this phenomenon for fabrication of diffractive optical elements is demonstrated.
University of Montpellier, France
Keynote: Nanoporous materials in wastewater treatment: How to improve their retention performance towards ionic pollutants in multi-component aqueous streams?
Time : 11:15-12:00
Jerzy Zajac is the Head of the Laboratory of Aggregates, Interfaces and Materials for Energy (AIME) belonging to the Charles Gerhardt Institute of Montpellier. His research interest and expertise is focused on the thermodynamics and modeling of interfacial phenomena occurring at solid-liquid, solid-gas and liquid-liquid interfaces and colloidal phenomena in solutions of surfactants and polymers, as well as the conception and preparation of porous multifunctional materials for high-added-value applications in the field of environmental remediation and liquid phase heterogeneous catalysis. He teaches at the University of Montpellier on fundamentals of inorganic and physical chemistry of the undergraduate program, as well as on colloids and interfacial phenomena at the master’s level.
Nowadays, many industries remain dependent on processes that produce wastewaters of a complex composition. There is a growing consensus in the research community about the deep implications the co-occurrence of various pollutants in complex aqueous streams may have for the efficiency of removal technologies. Among a variety of wastewater treatment technologies used to attain the Zero Pollution objective, sorption onto solid materials offers much promise, mainly because of the reduction of the volume of solid wastes to be stored in landfills and the reversibility of the phenomenon thus allowing the raw materials to be preserved. The important advances in the synthesis and investigation of functional nanostructured materials have attracted the interest of researchers and engineers working in the area of environmental remediation. The potential ecotoxicity and difficulty of use of nanoparticles rather limit their application, whereas nanoporous sorbents offer new advantages based on their size-dependent performance. Very systematic studies have been made for years in Montpellier on the sorption mechanisms of hazardous ionic species (e.g., heavy metal cations, oxyanions, ionic dyes and surfactants) onto inorganic solids possessing regular nanoporosity (e.g., zeolites, mesoporous aluminosilicates, layered mineral oxides). Combined use of various experimental techniques supplemented by appropriate modeling studies has shed light on the physical and chemical characteristics of sorbents crucial to the improvement of their retention performance in multi-component aqueous solutions. It is clear that an efficient wastewater treatment cannot be based only on a simple ion-exchange mechanism. Firstly, it is important to make short-range bonding forces involved in the retention of ionic species. Secondly, the confinement effects due to the adsorbent porosity and accompanied by some changes in the hydration layers surrounding the adsorbing ions also contribute to ensure a good selectivity of the treatment process. They will be thoroughly discussed and illustrated by numerous examples.
Xiamen University, China
Keynote: Challenges to nanoscience and nanotechnology: Intriguing nanosize effect and nanotime effect
Time : 12:00-12:45
Xianfang Zhu is one of the earliest scientists who initialized nanoresearch in China with over 30 years of research, teaching and industrial experience in a wide range of materials science and engineering areas. He has received PhD at the Australian National University followed up with a Postdoctoral experience at University of Illinois at Urbana, Champaign. He is presently the Director of the China-Australia Joint Laboratory for Functional Nanomaterials, an Adjunct Professor at The University of Queensland and a Full-Time Professor at Xiamen University, as well as the Chief Scientist for the AMAC International Inc., USA. Previously, he had also worked as a Senior Researcher in the Jefferson Lab and as an Assistant Professor at the University of Georgia. His current research interests are focused on nano-instabilities, nanoprocessing and nanofabrication. He has co-authored over 100 publications, filed 10 patents, chaired and co-chaired or served as Committee or Advisory Board Member at over 30 international and national conferences and presented over 70 invited lectures and talks at universities, research institutes and major international conferences worldwide and is Editor-in-Chief, Associate Editor of several international journals.
We first introduce a novel nanosize concept and a novel nanotime concept along with reviewing a series of novel phenomena and novel techniques related to nanosize effect and ultrafast process, which were recently discovered in our lab or were reported in literature. In these concepts, for the first time we are able account for the non-equilibrium, amorphous-like, and nonlinear nature of the current nanoscience and nanotechnology. In particular, we demonstrate that the structure instabilities of materials occur when a material system is limited to a space within a scale that is comparable to atomic distance. Such a nanosize effect is crucially dependent only on the nano-size but also on nanoshape or nanocurvature (including positive nanocurvature and negative nanocurvature). We also demonstrate that the structure instabilities of materials occur as well when the exchange of external energy with materials is limited to a time within a scale that is comparable to atomic vibration period. Such a nanotime effect can give rise to either soft mode or instability of atomic vibration in a condensed matter. The new concepts are very meaningful for control over fabrication and energetic beam processing of low dimensional nanostructures and nanodevices, especially for several potential applications related to nanoparticles, nanocavities, carbon nanotubem and nanowires. The new concepts have similarly important implications for chemistry, biology, and medicine as demonstrated by immerging new findings about nanocavities and nanolaser irradiation. In biology and medicine, there are widespread research interests either in using nanocavity (shell-core) structure to design and build biology composites, biosensors, drug deliverer and protein structures or in nanosurgery via ultrafast nanolaser processing, both being operative at the molecular level dealing with the concepts put forward herein.