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%).
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.
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
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
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)
Die Grundlagen der Atomtheorie / Abhandlungen von J. Dalton und W. H. Wollaston ; herausgegeben von W. Ostwald. - Leipzig : Wilhelm Engelmann, 1889. - 30 p. ; 20 cm. - (Ostwald's Klassiker der ...exakten Wissenschaften ; 3)
Die Grundlagen der Atomtheorie / Abhandlungen von J. Dalton und W. H. Wollaston ; herausgegeben von W. Ostwald. - Leipzig : Wilhelm Engelmann, 1889. - 30 p. ; 20 cm. - (Ostwald's Klassiker der exakten Wissenschaften ; 3)
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