Day 2 :
Keynote Forum
Yutaka Ohno
Tohoku University, Japan
Keynote: Chemical nanoanalyses of Si grain boundaries towards the fabrication of highfunctional Si solar cells
Time : 09:15-10:00
Biography:
Yutaka Ohno (PhD: Physics) is working in the Institute for Materials Research, Tohoku University (http://www-lab.imr.tohoku.ac.jp/~yutakaohno/). He is also working in the CREST research project (Grant No. JPMJCR17J1 (2017-2023)) in Japan Science and Technology Agency. A focus is on quantitative analyses of the impurity segregation ability of grain boundaries in Si and compounds by atom probe tomography (APT, with a spatial resolution less than 0.4nm) combined with scanning transmission electron microscopy (STEM) and ab initio calculations, but also on the study of atomistic structures of semiconductor nanostructures by optical measurements (cathodoluminescence, micro-photoluminescence, near-field optical measurements) under TEM.
Abstract:
Polycrystalline materials with grain boundaries (GBs), involving excess free energy because of their structural imperfection, can reduce their energy by the nanoscopic structural changes of the GBs via impurity segregation. Those local changes at GBs can stabilize non-equilibrium nanostructures, resulting in the drastic change in the macroscopic properties of those materials. The mechanism of GB segregation is, however, far from being understood due to difficulties in characterizing both crystallographic and chemical properties of the same GB at atomistic levels. We have therefore developed an analytical method to determine the impurity segregation ability on the same GB at the same nanoscopic location by a joint use of atom probe tomography (APT) and scanning transmission electron microscopy (STEM) combined with ab initio calculations, and discussed the segregation mechanism at atomistic levels. Three-dimensional distribution of impurity atoms was systematically determined at the typical large-angle GBs, small-angle GBs, and dislocations on GBs in Si by APT with a high spatial resolution (about 0.4nm), and it was correlated with the atomic stresses around the GBs estimated by ab initio calculations based on atomic-resolution STEM data. It was shown that impurity atoms preferentially segregated at the atomic positions under specific stresses so as to attain a more stable bonding network by reducing the local stresses. For example, the number of segregating oxygen atoms per unit GB area (NGB) is proportional to both the number of the stressed positions per unit GB area (nbc) and the average concentration of oxygen atoms around the GB ([Oi ]) with NGB ~ 50nbc[Oi ].
Keynote Forum
Yuko Ichiyanagi
Yokohama National University, Japan
Keynote: Characterization of ferrite nanoparticles and application for theranostics
Biography:
Yuko Ichiyanagi is an Associate Professor at Yokohama National University since 2009 (Applied Physics) and Osaka University since 2017. She was invited and chaired at several international conferences. Now she has published more than 50 papers and books. has been serving as an International Advisory Committee Member of some reputed conferences.
Abstract:
Magnetic nanoparticles have drawn attention recently due to their interesting nanoscopic features and potential applications for not only recording electric materials but also in the biomedical field. Previously, we obtained monodispersive magnetic nanoparticles (MNPs) by an original wet chemical method and reported magnetic, structural and thermal properties. Local structure analysis by X-ray absorption fine structure (XAFS) was useful to estimate nanoscale materials. We also suggested some biomedical applications using MNPs after functionalization. These functional MNPs were further introduced into cells. Furthermore, cancer cell selective MNPs were developed. Based on these techniques, we proposed a therapeutic method of magnetic hyperthermia. Now we propose “theranostics” by development nanoparticles for diagnostic and therapeutic materials simultaneously. For the therapeutic part, several kinds of ferrite NPs were prepared and AC magnetic measurements were performed. The relationship between the imaginary part of magnetic susceptibility χ” and the increase in temperature in the AC field was estimated. We have carried out in vitro experiments using cultured human breast cancer cells, and a drastic hyperthermia effect was observed. As one of the diagnostic method, mass spectrometric imaging (MSI) was proposed. With this method, the targeting analyte can be detected only with the nanoparticles as matrices, and simultaneously we can see the distribution of the materials by mapping the spectra. By means of our matrices, targeting analyte of very low molecular weight was successfully detected. Furthermore, effective parameters for MRI contrast agent, signals of the third harmonic components for magnetic particle imaging (MPI) were observed.
Keynote Forum
Taro Toyoda
The University of Electro-Communications, Japan
Keynote: Appearance of anisotropic optical absorption, ground state energy, and crystal growth of CdSe quantum dots adsorbed on the (001) and (102) surfaces of anatase-TiO2
Biography:
Taro Toyoda has completed his DSc from Tokyo Metropolitan University and Assistant Research Officer at National Research Council of Canada. After working at Fuji Electric Company and Nippon Mining Company, he was appointed as a Professor of The University of Electro-Communications. His research focuses on basic studies of optical properties in semiconductor quantum dots including photoexcited carrier dynamics and their applications to photovoltaic quantum dot solar cells. He has published more than 200 papers in reputed journals.
Abstract:
The present study focuses on the effect of the substrate surfaces with different crystal orientations on optical absorption and ground state energy in a system comprising CdSe quantum dots (QDs) adsorbed on (001) and (102) surfaces of anataseTiO2 (A-TiO2 ). We applied photoacoustic (PA) spectroscopy based on the photothermal phenomenon to characterize the optical absorption, not only in the bandgap absorption but in the sub-bandgap region owing to high sensitivity. Photoelectron yield (PY) spectroscopy is useful for determining the absolute ground state energy level of QDs. Adsorption time dependence by absorbance measurements shows that (1) the adsorption rate of CdSe QDs on A-TiO2 (001) is higher than that of A-TiO2 (102) in agreement with our DFT calculations ((001) >> (101) > (102)), and (2) the diameter increasing rate of CdSe QDs on A-TiO2 (102) is higher than that of A-TiO2 (001), indicating the anisotropic crystal growth. The ground state energy levels of CdSe QDs on A-TiO2 (102) are deeper than those on A-TiO2 (001), suggesting the impossibility of the sensitization from the excited state of CdSe QDs to the conduction band of A-TiO2 (102). Deeper value of the ground state energy level of CdSe QDs on A-TiO2 (102) than those on A-TiO2 (001) is the possibility due to the difference of the permittivity of A-TiO2 (001) and A-TiO2 (102).
Keynote Forum
Rita John
University of Madras, India
Keynote: CoFeNbZ (Z = Al, Si and In) quaternary heusler alloys – A first principle study
Biography:
Rita John is Professor and Head, Department of Theoretical Physics, University of Madras, Chennai, India. She is Visiting Professor on Fulbright Fellowship at the Department of Physics and Astronomy, Texas Christian University, Fort Worth, Texas, USA (2014). Her area of research includes Computational/Theoretical Condensed Matter Physics. She has published over 50 papers in peer-reviewed journals. The book titled ‘Solid State Physics’ authored by her and published by Tata McGraw Hill publisher (2014) is used by Physics graduate students globally. She has edited and published 4 other books on advanced topics in Physics. She has also authored a book titled ‘Science uncovers the signature of God’ highlighting the scientific facts recorded in the Holy Bible. She is the recipient of various awards and prizes for her academic contributions.
Abstract:
Heusler alloys are intermetallic compounds made up of four interpenetrating fcc sublattices. Some of them have multifunctional nature i.e. a combination of functions (properties) within the same compound, which have technological applications. Co-based Heusler compounds gained considerable attention in the recent past due to their high Curie temperature, high spin polarization and tunable electronic structure with possible applications in spintronics. They have the general composition X2 YZ where X and Y are transition metals and Z is an sp element. Quaternary Heusler alloys (QHA) are formed when one of the X atoms is replaced by a third transition metal. In this study, the structural, electronic, magnetic and transport properties of CoFeNbZ (Z=Al, Si and In) quaternary Heusler compounds are investigated employing the full potential linearized augmented plane wave (FP-LAPW) method implemented in WIEN2k code within the density functional theory prescription. The exchange and correlation effects are treated by using generalized gradient approximation (GGA). From the electronic and magnetic properties, it is found that CoFeNbAl is a half-metal with a spin flip gap of 0.33 eV and satisfies the Mt =Zt –24 Slater Pauling rule. It is known that GGA underestimates the band gaps of semiconductors and insulators. Here, the Tran and Blaha modified Becke Johnson potential (TB-mBJ) is used to obtain accurate band gaps. The spin-flip gap increases to 0.34 eV with the use of TB-mBJ and the nature of gap changes from indirect to direct. The half-metallic gap in CoFeNbAl arises due to the complex hybridization between the d-states of transition metals Co, Fe, and Nb. CoFeNbIn has metallic behavior in both spin channels. CoFeNbSi is a near half-metal with a near integer magnetic moment. The effect of hydrostatic strain on the magnetic and half-metallic properties of CoFeNbAl is determined. The transport coefficients such as the Seebeck coefficient, electrical conductivity, and thermal conductivity are computed in combination with the second principles BoltzTraP code. In the spin-up channel, electrical conductivity decreases as a function of temperature whereas it increases in the spin down the channel for CoFeNbAl. This affirms the metallic behavior in the spin-up channel and the semiconducting behavior in the spin down channel. The high spin polarization and robustness of half-metallicity against hydrostatic strain make CoFeNbAl a potential candidate for spintronic applications.
Keynote Forum
Feroz Alam Khan
Bangladesh University of Engineering and Technology, Bangladesh
Keynote: Influence of Mn substitution on magnetoresistance and magnetic properties of (Fe1-xMnx ) 75P15C10 alloy ribbons
Biography:
Feroz Alam Khan has completed his PhD degree from the Bangladesh University of Engineering and Technology (BUET) and his Postdoctoral Research at the University of Delaware, USA, University of Uppsala, Sweden, and the University of Tsukuba, Japan. He is a Professor in Physics at the Bangladesh University of Engineering and Technology (BUET). He is a leader of a research group called Dhaka Materials Science Group under a scientific research collaboration with the International Science Programs (ISP), Uppsala University, Sweden. He has supervised more than 25 postgraduate degrees that include Masters, MPhil, and PhD degrees. He has to his credit more than 50 research publications. He is involved in promoting basic science research through the establishment of regional research collaborations with the south-east Asian Universities under the umbrella of International Science Programs.
Abstract:
Magnetic properties have been measured on a rapidly cooled melt spun (Fe1-xMnx )75P15C10 (x=0, 0.05, 0.1, 0.2 and 0.3) amorphous alloys ribbons. The amorphous property of the ribbons have been confirmed by X-ray diffraction and scanning electron microscopy analysis. The observed magnetic properties e.g. magnetization and magnetoresistance and the ac permeability indicate that (Fe1-xMnx )75P15C10 goes through a transition from the ferromagnetic to antiferromagnetic-like phase within the temperature range of observation. Both positive and negative magnetoresistance have been observed at room temperature for different electrical circuital configurations as a function of the applied magnetic field. Saturation magnetization (Ms ) and the low field coercivity (Hc ) at room temperature indicates the magnetic softness of the alloy. The temperature dependent ac permeability shows high effective permeability at room temperature and shows a permeability minima around 450K. The ac permeability shows a maximum around 1kHz and diminishes at the high-frequency regime. The magnetoresistance of all the samples goes through a minimum around 4kOe showing a spin-valve type behavior which may be attributed to the suppression of quantum localization of the spin moments.
Keynote Forum
John Owen Roberts
Independent Researcher, UK
Keynote: Implications of the link between the periodic table and the standard model
Time : 14:15-15:15
Biography:
John Owen Roberts graduated in 1969 with a BSc (Hons) in Physics from The University of Liverpool. He has been an Open University Tutor for 30 years and a private tutor of Maths and Science. He is the author of “Those Infinities and the Periodic Table” (ISBN 978-0-9934667-3-1). He has had published an article “Proposed Link between the Periodic Table and the Standard Model”, July 2017 in the journal Materials Science and Engineering.
Abstract:
The mathematics of quantum physics from the standard model using groups U(1)xSU(2)xSU(3) and the Pauli Principle produces two sets of time independent quantum states n(n+1) and n(n-1) where n is the principal quantum number. Oscillations between these states result in a one to one mapping with the Roberts-Janet Nuclear Periodic Table by interpretation of n>0 for condensed matter and n<0 for plasma prior to fusion. The mechanism provides a framework for Periodic Tables for every supernova by excluding mass number. In the lower half of the table occupation by bosons leads to increased energy densities in which an ensemble of outcomes is discussed. A hypothesis of string theory is proposed at the nuclear end of the table merging into quantum loop gravity at the condensed matter top end of the table.
Keynote Forum
Thomas E Kodger
Wageningen University & Research, The Netherlands
Keynote: Moldable soft polymers through topology
Time : 15:40-16:05
Biography:
Thomas E Kodger completed his PhD from Harvard University in 2015 under Professor David Weitz and Postdoctoral studies from the University of Amsterdam with Professor Peter Schall. He is currently an Assistant Professor in the Physical Chemistry and Soft Matter Laboratory at Wageningen University & Research in The Netherlands having joined in 2017.
Abstract:
Man-made rubbers, have excellent mechanical toughness but are inherently stiff due to topological constraints are known as entanglements, which prevent polymer chains from crossing and act as crosslinks. Thus, entanglements place a theoretical lower bound on how soft elastomers can be made without adding liquid fillers; soft materials with Young’s moduli, E<0.2MPa are composed of multiple components and are not chemically pure substances. By introducing liquid fillers to polymeric materials, the stiffness may be decreased, however, this swollen material is mechanically brittle and leaks the filler material upon deformation inhibiting their use in many applications. Additionally, this swelling with solvent hinders their ability to be formed or molded into structures. In this talk, I will discuss the synthesis of soft, moldable elastomers. This material is synthesized using controlled living polymerization techniques to fabricate a triblock copolymer with a middle block of silicone polymers in a ‘bottlebrush’ architecture which eliminates entanglements making the material soft without the necessity for the solvent. The triblock polymer includes functional end blocks composed of a thermoplastic, polystyrene, which undergoes a glass transition upon cooling, allow this material to thermoset reversibly, that is 3D printed. I will present the synthesis and mechanical characterization of this material and high-resolution 3D printing of finely detailed soft structures.
Keynote Forum
Barbara A Jones
IBM Research–Almaden, USA
Keynote: Electronic properties of Mn-decorated silicene and other 2D materials
Time : 16:20-16:45
Biography:
Barbara A Jones has been at IBM Almaden since 1989, working in a variety of areas from modeling magnetic recording devices to magnetic atoms on surfaces as studied by STM. She got her PhD from Cornell University in 1988, followed by a postdoc at Harvard. She is on the Board of Physics and Astronomy of the National Academy of Sciences, an officer of the Physics Section of the AAAS, and an Honorary Member of the Aspen Center for Physics. She has been on the Editorial Boards of Physical Review X, Physical Review B, and Journal of Low-Temperature Physics.
Abstract:
We first discuss silicene on hexagonal boron nitride, using first-principles calculations. Since hexagonal boron nitride is semiconducting, the interaction with silicene is weaker than for metallic substrates. Therefore, it is possible to open a 50meV band gap in the silicene. We further address the effect of Mn decoration by determining the onsite Hubbard interaction parameter, which turns out to differ significantly for decoration at the top and hollow sites. The induced magnetism in the system is analyzed in detail, and we compare and contrast with the behavior of other pairings of magnetic adatoms and 2D surfaces.
Keynote Forum
Gennadiy Filippov
Chuvash State Pedagogical University, Russia
Keynote: Density matrix in description of the collision of atomic particle with solid film
Time : 16:45-17:10
Biography:
Filippov has his expertise in particle-solid interaction physics. He has completed his PhD at the age of 54 years from Tomsk State University (Russia). He is head of the Laboratory of Biophysics and Bio-nanotechnology in the Chuvash State Agricultural Academy and professor in the Chuvash State Pedagogical University in Cheboksary, Russian Federation.
Abstract:
Calculation and further analysis of density matrix (DM) for a projectile which collides with a solid film reveal some new representations which hard to be anticipated without the calculation. Namely: 1. The coherence properties in the projectile’s wave field are describing through the special function of coherence. ( , ,. ) ( , . ) 2 ( , ,. ) ( , ,. ) 1 1 2 2, 1 2 1 2 x x t x x t x x t f x x t ï² ï² ï² ï² ï² ï² ï² ï² Γ Γ Γ + = , where ( , ,. ) ( , . ) 2 ( , ,. ) ( , ,. ) 1 1 2 2, 1 2 1 2 x x t x x t x x t f x x t ï² ï² ï² ï² ï² ï² ï² ï² Γ Γ Γ + = - density matrix of the projectile depending on two spatial points 1 2 x , x ï² ï² and the time t. 2. The collision with the solid leads to a significant decrease in the total coherence length of the projectile’s wave field. The coherence length can become much smaller than the initial size of a wave packet of a particle passing through the film. 3. During the collision with solid, the number of different spatial areas where the mutual coherence in the projectile’s wave field is supported can be multiplied. 4. Every part of projectile’s wave field can be individualized as the separate particle having own property in its inner quantum state. The procedure which has a responsibility for such a transformation can be characterized as a spontaneous breaking of symmetry. 5. The process described in point 3 can be considered as a special form of breaking in quantum mechanics. 6. Knowing the wave packet evolution during the passage through the solid film allows one to explain experimental results on the pore formation during the passage of high charged atomic ions through the thin carbon nano-membranes. 7. The parts of the wave field considered above can be stabilized in its quantum state after been captured in its own polarization well.
Keynote Forum
Paul Leifeh Njuabeh
The University of Bamenda, Cameroon
Keynote: Seismic Imaging of soils for slope stability in Ngoketunjia divison, North west region Cameroon
Time : 17:10-17:35
Biography:
This study has been conducted around the Ngoketunjia slope in Ngoketunjia Division, Northwest region, Cameroon, West Africa, on the subject, seismic imaging of soils for slope stability in Ngoketunjia division. Subsequently, the probability of failure of the real slide in Ngoketunjia. The most valuable infrastructural assets of this division are aligned along the feet of these slope coupled with the habitual human activities and settlement, whereas findings of the stability of these slopes have not yet been ascertained. Following these highlights, we are likely to say that, both materials properties and human lives may be exposed to the risk of instability of the slopes. In this paper, we describe how state-of-the-art 3-D seismic data can be acquired, analysis, interpreted, integrated with other data and then used to improve the geographical design of the slope and ascertain its stability. The primary imaging targets were heterogeneous siltstone and fine-grained sandstone successions approximately 100ft (30m) thick and comprised of complex assemblages of thin lobe-like deposits having individual thicknesses of 3 to 6ft (1 to 2m). Secondary data was generated from a write-up that was examined in 2003 at the depth of approximately 6600ft (2000m) by The Upper Noun Valley Development Authority. A geographical survey was conducted on the slope, followed by three soil test (identification, characteristics, and porosity) that were conducted on soils sample collected in strata from the slope. The effect of various parameters including slope inclination angle, the angle of internal friction of soil, horizontal seismic loading, the cohesion of the silos and surcharge loading has been examined. After analyzing our results, we found out that the stability of a sloping soil is largely affected by the horizontal seismic forces. We show by the careful consideration that, given the prevailing climatic changes that keep increasing the water table content of the slope year by year, thereby increasing the porosity of the soils may lead to the failure of the slope. Secondly, the habitual human activities like excavations and construction, which keeps increasing the load sustained by the slope have led to a drastic increase in the driving forces along the different sections of the slope and consequently the factor of safety. Mitigation measures like bio-restoration, drainage systems, retaining walls, rock bolting were advised to the municipality of Ndop Central Sub Division. The cost of carrying out the study, lack of potable or mobile equipment to use during the study and the unavailability of related publications were some of the limitations to the study and we are proposing that further research works should take into consideration these limitations in other to address major global concerns in this area of study.
Abstract:
Paul Leifeh Njuabeh, is a holder of an Executive MBA in management and a prospective MSc in Condensed matter physics, his age of 28 years from Bamenda University. He is serving at the Ministry of public contracts Cameroon as the chief of bureau for Infrastructural contracts in Ngoketunjia Division, Cameroon. Before joining the Ministry of public contracts, he has earlier serve at the Ministry of Education Cameroon as an instructor and a statistician.