Lattice deformation and electronic properties are closely linked in two-dimensional materials such as graphene. However, a fine control of the spatial strain distribution is crucial to correctly ...engineer the electrical properties of atomic-thick materials. Although several solutions have been proposed so far, the flexibility required to fully master and investigate arbitrary strain profiles remains challenging. Here, we locally deform graphene using the poly-methyl-methacrylate (PMMA) shrinkage induced by electron-beam irradiation. Arbitrary design of pulling geometries and different actuation magnitudes can be both defined in the PMMA by electron-beam patterning. Specific graphene strain fields can be obtained using reverse engineering of the PMMA micro-actuators geometry. As proof of principle of operation, we target and we successfully demonstrate a strongly localized and virtually-pure uniaxial strain profile. This configuration is promising for the implementation of the pseudo-magnetic field and allows identifying the graphene crystal orientation. Strain field characterization and out-of-plane graphene deformations are demonstrated and studied by Raman, scanning-electron and atomic-force microscopy. These can all be easily combined with the present device architecture. Remarkably, the induced strain in graphene can be released by heating the sample and reconfigured or restored again by re-irradiating the polymer. In situ observation of nano-mechanical evolution of devices show that micro-actuation can be strong enough to tear the graphene layer. As side result, the in situ failure visualization allows using our technique to qualitative estimate the mechanical quality of chemically synthetized graphene. The relative simplicity and flexibility of our method opens new opportunities for the investigation of straintronics, pseudo-magnetic field and nano-mechanics in two-dimensional materials.
This book looks at the life and personality, the scientific and philosophical work of Ludwig Boltzmann, an Austrian physicist who made significant contributions to the development of the atomic ...theory. His tragic life, which ended in a suicide, is described in detail. A substantial part of the book is devoted to discussing his work establishing the atomic structure of matter, and his influence on modern physics. Boltzmann stands as a link between two other great theoretical physicists: James Clerk Maxwell in the 19th century and Albert Einstein in the 20th. Maxwell, who is best known for his discovery of the laws governing electric and magnetic fields and light, first found the formula for the probability distribution of velocities of particles in a gas in equilibrium, but it was Boltzmann who derived the equation governing the dynamical evolution of the probability distribution, according to which the state of a gas, not necessarily in equilibrium, will actually change. Boltzmann's ideas were central to Max Planck's later analysis of black-body radiation at the turn of the century, in which he introduced the quantum of action, thereby firing the opening shot of the quantum revolution. In 1905, Einstein not only picked up on this idea and developed it further (in effect showing that the ‘atomic hypothesis’ applied even to light itself) but was also influenced by Boltzmann's concepts in two of his other famous papers of 1905, one in which he provided a method of determining molecular dimensions and the other in which he explained the nature of Brownian motion.
Amberlite XAD-2 has been functionalized by coupling it, through the NN group, with Pyrocatechol Violet (PV), and the resulting resin has been characterized by elemental analysis, thermogravimetric ...analysis (TGA) and IR spectra. The resin has been used for preconcentrating Zn(II), Cd(II), Pb(II) and Ni(II) ions prior to their determination by flame atomic absorption spectrometry. The optimum pH values for quantitative sorption are 5, 5–7, 4, and 3 for Zn, Cd, Pb and Ni, respectively. The four metals can be desorbed (recovery ~98%) with 4 M HNO
3; also, 4 M HCl is equally suitable except for Zn. The sorption capacity of the resin is 1410, 1270, 620 and 1360 μg g
−1 resin for Zn, Cd, Ni and Pb, respectively. The effect of F
−, Cl
−, NO
3
−, SO
4
2− and PO
4
3− on the sorption of these four metal ions has been investigated. They are tolerable in the range 0.01–0.20 M, for Pb. In the sorption of Zn(II) and Ni(II), the tolerance limits of all these ions are upto 0.01 M, whereas for Cd(II), F
−, NO
3
−, and PO
4
3− have been found to be tolerable upto 0.50, 0.10 and 0.10 M, respectively. The preconcentration factors are 60, 50, 23 and 18 for Zn, Cd, Pb and Ni, respectively. Simultaneous collection and determination of the four metals are possible. Cations commonly present in drinking water do not affect the sorption of either metal ion if present at a concentration level similar to that of water. The method has been applied to determine Zn, Ni and Pb content of well-water samples (RSD ≤9%).
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Računanje višefotonskih procesa polazi od vremenskog računa smetnje u kojem je glavni problem, pri određivanju vjerojatnosti procesa, provođenje beskonačne sumacije po međustanjima atoma. Za ...rješavanje ovog problema razvijeno je više matematičkih metoda. Osnovni cilj ovog rada je usporedba različitih metoda koje se koriste u teoriji višefotonskih procesa. U tu svrhu izložen je pregled metoda i provedena komparacija dobivenih rezultata na dvofotonskim procesima. Račun je proveden na vodiku sličnim atomima, jer su ovi jednostavni sustavi prikladni za računanje svim izloženim metodama.
Arbitration methods are needed to prevent conflicts when several processing units share a common resource. Despite of there being a plethora of different arbitration methods available, there is not ...an optimal solution for every case. Our case requires a distributed, modular, simple, fast, freely scalable, and inexpensive arbitration method. Emerged from our special need, we have developed a simple daisy chain type of arbitration that is modularly expandable and implements a geographical priority scheme with a possibility for dynamic priority. This arbitration can be implemented with two inexpensive 74-series logic gates or programmable logic. It can be used with systems that require arbitrary modular scalability, few IO-lines and low cost.
Articolul face o analiză fizică și filosofică a originii lumii, din ce e format universul și cum a apărut viața pe Pământ. Autorul face referire la teoriile lui Gustav Le Bon din lucrarea ..."L'évolution des force" și ale lui Newton referitoare la crearea Universului
o revizuire a teoriei descendenței
teorii și ipoteze noi în științe
Numele real al autorului: Mihail Lungianu
Considerații privind natura și dimensiunile materiei universului și ale atomului, alături de o analiză a teoriei lui Gustave Le Bon
Traditionally, embedded system design process demands a considerable amount of expertise, time and money. This hinders the testing of new research results in robotics with real embedded systems, ...which would be required in order to bring the research results into real use. We have earlier presented an easy and fast embedded system development concept based on embedded objects. Embedded object concept utilizes common object oriented methods used in software by applying them into combined Lego-like software and hardware entities. This concept enables people without comprehensive knowledge in electronics or embedded systems design to create new embedded systems. In this paper, we present an implementation of the embedded object concept as Atomi-objects, and we show how these objects can be mapped to UML, a notation commonly used in object oriented software development, through an example of creating a simple cleaning robot. The significance of this paper is to present the presuppositions for the embedded object concept to be used with object oriented design methods.
Les atomes / pr Jean Perrin . - Troisième édition. - Paris : Librairie Félix Alcan, 1913. - XVI, 295 p. : ill. ; 19 cm. - (Nouvelle Collection Scientifique)
Les atomes / pr Jean Perrin . - Troisième ...édition. - Paris : Librairie Félix Alcan, 1913. - XVI, 295 p. : ill. ; 19 cm. - (Nouvelle Collection Scientifique)
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