Science and public engagement

Over the last decade, social media has changed our way of communicating, both privately and professionally. Science has also been overwhelmed by this abrupt change. Today's calls for national and international projects require a strong commitment also to the public engagement. A good practice of science and public engagement can be a benefit for a scientific career, an opportunity for young people who want to approach this profession, and not less an important rawplug in the relation with politics.     

On the growth of small crystals of Cd, Zn, Pt and Rh during electron microscope observations

The growth of small supported metal crystals under the influence of an electron beam has been studied in real-time using a 400 keV ultra-high-resolution electron microscope. Samples of Pt, Rh, Cd and Zn supported on amorphous C or Si films were prepared ex situ and crystal growth in situ was recorded directly using a TV imaging/video system attached to the microscope. The different types of observed crystal growth are reported: the fcc metals (Pt and Rh) grow by coalescence, or by the addition of atoms along the particle surface followed by structural rearrangements which result in approximately spherical particles. The hcp metals (Cd and Zn) grow in the form of long rafts along the surface of the substrate film.     

Report on the results of the 2001 Struchkov Prize competition for young scientists and announcement of the 2002 competition

Information

Report on the results of the 2001 Struchkov Prize competition for young scientists and announcement of the 2002 competition     

Design and synthesis of small molecules with difluoroquinoxaline units for OSCs

Abstract

We designed and synthesized three novel small molecule donors (SM1, SM2 and SM3) that consist of thiophene as the electron-donating end group and 6,?7-?difluoroquinoxaline moiety as a novel electron-withdrawing core group. The organic low band gap molecules with 6,?7-?difluoroquinoxaline and thiophene units were synthesized using Stille coupling to generate SM1, SM2 and SM3. The absorption of SM2 and SM3 in solution was red shifted due to increased conjugation length of added thiophene units. In case of SM2 and SM3, introduction of hexyl chain in terminal thiophene units improve solubility in organic solvent. The maximum absorption peaks of SM1, SM2 and SM3 in solid thin films were at 482, 505 and 518?nm, respectively. SM3 was red shifted as compare to SM2 due to increased π-π stacking of electron donor materials.     

Effective kinetic coefficients for some binary metallic alloys within the small and finite supercooling region

The normal crystallization kineties concerning the base of In, Rb, Ga some binary metallic melts either within the small supercoolings (Δ T ≦ 1 K) or finite ones (ΔT ≦ 20 ÷ 60 K) has been considered. When crystallizing the binary alloys: In + 2.3 at.% Pb; Rb + 10 at.% K; Ga + 2 at.% Sn; Ga + (2; 4; 8) at.% In; Ga + (0.5; 3.5) at.% Zn; Ga + (5; 8; 10) at.% Zn very dilute binary solid solutions are supposed to be formed. The solid solutions have the B-component distribution coefficients which are either much less or less compared with unit, i.e. k_B ≦ 1, k_B < 1 in all the layers of diphase transition region separating the melt from the crystalline phase. By virtue of fluctuation theory of normal crystal growth within the small and finite supercoolings' region for the above-mentioned binary metallic melt some effective kinetic coefficients have been calculated. A good agreement between theoretical effective kinetic coefficients and available experimental ones in the case of given binary systems has been established.     

Results of the 2005 Struchkov Prize competition for young scientists and announcement of the current (tenth) 2006 competition

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Results of the 2005 Struchkov Prize competition for young scientists and announcement of the current (tenth) 2006 competition     

3D printed models of small and large molecules,structures and morphologies of crystals,as well as their anisotropic physical properties

Three‐dimensional (3D) physical models of atomic structures of crystals, their anisotropic properties and morphologies as well as models of small and large molecules were printed with support from 3D Systems Corporation. Structural information in Crystallographic Information Framework (CIF) files from the Crystallography Open Database and the Protein Data Bank was utilized. Computer programs were either newly developed (Cif2VRML) or enhanced by 3D print file export functions (WinXMorph and WinTensor) in order to design most of these models. Current 3D printing technologies are briefly reviewed. The literature on the impact on students’ comprehension and retention of structural information with access to such models is assessed. Our taking of a historical perspective in this paper illustrates that the usage of models has for more than 200 years been an integral component of crystallography.     

Wide and small angle X-ray scattering measurements for expanded fluid Se accompanying the semiconductor–metal and metal–nonmetal transition

Wide and small angle X-ray scattering measurements for supercritical fluid Se in the wide density region from liquid to dense vapor have been carried out using synchrotron radiation at SPring-8. The large background for the small angle spectra with the previous high-pressure vessel was much suppressed using a new vessel with a large diamond window. We carefully measured wide angle X-ray scattering near the critical density and obtained the structure factor, S(k), and the pair distribution functions, g(r). By small angle X-ray scattering measurements, we succeeded in observing a medium-range fluctuation in the semiconductor–metal transition in expanded fluid Se.     

On the results of the 2009 Struchkov Prize, a competition for Young Researchers, and the announcement of the current (14th) competition for 2010

Information

On the results of the 2009 Struchkov Prize, a competition for Young Researchers, and the announcement of the current (14th) competition for 2010     

Polyhedral stability ‐ on the growth of flat crystal faces on small molecule and protein crystals

The old standing problem of face morphology is discussed. A special emphasis is put on the macroscopically flat faces, appearing on small molecule crystals mostly during calm growth, under low supersaturations. As distinct, protein crystals are growing with macroscopically flat faces even under surprisingly high supersaturations. Explanations of these facts are suggested by considering the surface micro‐profile of crystal faces which growth is driven by screw dislocations. It is shown that, due to kinetic reasons, the tips of the growth hillocks and the valley between them have to be levelled to some extent (at least on a quasi‐atomic scale) under low enough supersaturations. The amplitude of the surface roughness has to be suppressed also due to the surface energy gain, especially under quasi‐equilibrium. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Surface reconstruction phase diagrams for InAs, AlSb, and GaSb

We present experimental flux-temperature phase diagrams for surface reconstruction transitions on the 6.1 Å compound semiconductors. The phase transitions occur within or near typical substrate temperature ranges for growth of these materials by molecular beam epitaxy and therefore provide a convenient temperature standard for optimizing growth conditions. Phase boundaries for InAs (0 0 1) [(2×4)→(4×2)], AlSb (0 0 1) [c(4×4)→(1×3)], and GaSb (0 0 1) [(2×5)→(1×3)] are presented as a function of substrate temperature and Group V-limited growth rate (proportional to flux), for both cracked and uncracked Group V species. We discuss differences between materials in the slopes and offsets of the phase boundaries for both types of Group V species.     

Study of the electronic properties of a double-chain model for Al-rich-transition-metal quasicrystals,amorphous, and crystalline phases

The electronic properties of quasicrystals containing transition-metals are studied employing a simple double-chain model within the tight-binding approximation. We show that, under determined conditions, spectral fine structures are the result of competing localized- and extended-like states, which are not observed in traditional one-dimensional aperiodic models. These spectral features can explain the experimentally observed transport properties. From this point of view this double-chain model mimics the behavior of electrons in realistic icosahedral quasicrystals. Moreover, in view of the electronic transport, the relationship between quasicrystals and related amorphous phases is explained in a natural way.     

Modelling the dynamics and control design for Czochralski,Liquid Encapsulated Czochralski and Floating Zone processes

The need for high quality crystals constantly rise. It is especially obvious in connection with the evolution of electronics and optoelectronics. At the present time all the basic methods for crystal growing are known. So the question arises – what further developments are needed to create further advances? Without doubt first of all it is necessary to speak about perfecting crystal growing equipment. Perfecting modern equipment will enhance and accommodate the results of our understanding of the crystallization physics and provide solutions to the various physical tasks at the atomic and macroscopic levels. Each new step in the process of perfecting the technology and production processes demands large intellectual and material inputs. The continual updating of pullers requires constructive solutions and control systems. Mathematical modelling of the methods of crystallization enables one to more rapidly create the software for the digital systems which are a feature of the latest achievements of physics, that is IT engineering and the modern theory of automatic control.Here we consider the problem of mathematical modelling of crystallization processes from the melt by Czochralski, Liquid Encapsulated Czochralski and Floating Zone methods based on linearization of three conservation laws: the heat, mass and the growth angle constancy is reviewed in depth. Special attention is given to the problem of the dynamical analysis of these processes in open and closed states and to the synthesis of the digital control of crystal diameter for the weight technique. The main problems discussed involve the determination of the parameters required for calculating such control systems together with the use of the multichannel parametric PID regulator involving the state variable observer concept. In addition briefly considered are the problems of digital filtering of the measurement noise based on multidimentional Kalman filters and the determination of mechanical stability limits for static menisci.     

The precipitation of alkaline-earth metal-nickel,aluminium (chromium (III) and iron (III)), silicyl(titanyl and zirconyl) hydroxide,carbonate and oxalate precipitate precursors for alkaline-earth metal oxyanion salt ceramics and allied materials – a review of small scale laboratory studies and industrial patents

The alkaline-earth metal – nickel, aluminium, chromium III, iron III, silicyl, titanyl and zirconyl hydroxide, carbonate and oxalate coprecipitates are the precursors for the preparation of the corresponding alkaline-earth metal oxyanion salt refractories, magnetics, dielectric and optical ceramics, cements and allied materials. The small-scale laboratory studies on the coprecipitations of these precursor materials, their compositions and the coprecipitation mechanisms are reviewed and the relevant industrial patents are described (140 references).     

X-Ray,Synchrotron and Mass-Spectrometric Methods for the Study of Ceramic Objects of Cultural Heritage

Crystallography Reports - Fragments of stamped amphorae (south Pontic (Sinope, III–I BC) and Mediterranean (Thasos, IV–III BC, and, presumably, Chios, III–II BC)), found in...     

Growth and characterization of two-dimensional crystals for communication and energy applications

This review article covers the growth and characterization of two-dimensional (2D) crystals of transition metal chalcogenides, h-BN, graphene, etc. The chemical vapor transport method for bulk single crystal growth is discussed in detail. Top-down methods like mechanical and liquid exfoliation and bottom-up methods like chemical vapor deposition and molecular beam epitaxy for mono/few-layer growth are described. The optimal characterization techniques such as optical, atomic force, scanning electron, and Raman spectroscopy for identification of mono/few-layer(s) of the 2D crystals are discussed. In addition, a survey was done for the application of 2D crystals for both creation and deterministic transfer of single-photon sources and photovoltaic systems. Finally, the application of plasmonic nanoantenna was proposed for enhanced solar-to-electrical energy conversion and faster/brighter quantum communication devices.