Negative-Mode LDI-MS of corrosion products on the surface of AgCu-X (X- Zn, Pd, In) alloys

Copper-silver alloys have widely applied in many different areas such as information and communication technology, rail transportation, power transmission lines, microelectronics, machinery manufacturing, chemical processing industries, coinage, ornamental parts, etc [1, 2]. A group of ternary Ag-Cu alloys with different elements is used for binding different materials (brazing, fillers, and pastes). For example, Ag-Cu-Pd alloys are used in dentistry, as amalgams improvers or joint fillers for different dental materials [3]. Ternary AgCuIn alloy uses as a bonding metal layer; the use of AgCuIn as the bonding metal, greatly reduces the manufacturing costs of LED chip and helps to improve the life of the LED chip. Copper and its alloys belong to the group of semi-noble metals however they are not highly resistant to corrosion in some of the environments [4, 5]. Corrosion has particularly attracted attention due to the significant impact on the performance and reliability of this industrially important material group in their applications, as well as on the economy. Standard methods for characterization of corrosion films are: X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM) with Energy Dispersive Spectroscopy (EDS) [6, 7]. The positive mode laser desorption ionization (LDI) mass spectrometry method can be successfully applied to analyze the composition of the corrosion film. In our previous work, it has been shown that the amount of sample required for the LDI method is much smaller than the sample quantity required for the methods mentioned above [8]. The purpose of this work was to study the possibilities of direct analysis of the corrosion films formed on Ag60Cu26Zn14, Ag58.5Cu31.5Pd10, and Ag63Cu27In10 alloys using the negative mode laser desorption ionization (LDI) mass spectrometry method. The corrosion films of Ag60Cu26Zn14, Ag58.5Cu31.5Pd10, and Ag63Cu27In10 alloys were obtained after anodic potentiostatic polarization treatment (at +0.25 V for 5 min in 3.5% wt. NaCl solution). Preliminary results show that the negative mode LDI mass spectra measured from the corrosion film of these alloys contains same ionsAgCl2 - , AgCuCl3 - , CuCl2 - , Cu2Cl3 - , Cu3Cl4 - . This result suggested that main reactions are the formation of CuCl layer on the surface of the Cu rich metallurgical phase and formation of AgCl film on the surface of Ag rich metallurgical phase. ACKNOWLEDGEMENT: This work is the result of the Projects OI 172019 and TR 34033, funded by the Ministry of Education, Science and Technological Development of the Republic of Serbia.VII International School and Conference on Photonics : PHOTONICA2019 : Abstracts of Tutorial, Keynote, Invited Lectures, Progress Reports and Contributed Papers; August 26-30; Belgrad

Due Auswahl der Experimentellen tiere in der untersuchung des parodontium

Mnogi problemi etiologije i patogeneze progresivnih parodontopatija još uvek nisu rešeni. Neophodna su buduća naučna istraživanja, u in vivo uslovima. Data je analiza osobina nekih eksperimentalnih životinja, bazirana na podacima iz literature i sopstvenom iskustvu. Izbor eksperimentalnih životinja, kao modela za parodontalna istraživanja, sa prednostima domaće svinje u eksperimentalne svrhe, autori su prodiskutovali sa posebnom pažnjom.A number of etiological and pathogenetic problems related to parodontal diseases are still insufficiently clarified. Further in vivo studies are necessary. The analyses of properties of some experimental animals based on literature data and own experience are presented. Particular attention is payed to the selection of experimental animal as a model for parodontal studies. Advantages of using domestic swine for xperimental purposes are discussed in details.Viele Probleme der Aetiologie und der Pathogenese der progressiven Parodontopathie sind noch nicht gelöst. Wissenschaftliche Forschungen in vivo scheinen uns nötig zu sein. Eigenschaften einiger experimentellen Tiere, aufgrund von Angaben aus der Literatur und anhand eigener Erfahrungen, werden angeführt. Die Autoren haben die Auswahl der experimentellen Tiere, die zu Versuchszwecken für parodontale Untersuchungen verwendet wurden, gründlich überprüft, mit besonderer Berücksichtigung der Experimente mit Schweinen

Noncommutativity relations in type IIB theory and their supersymmetry

In the present paper we investigate noncommutativity of $D9$ and $D5$-brane world-volumes embedded in space-time of type IIB superstring theory. Boundary conditions, which preserve half of the initial supersymmetry, are treated as canonical constraints. Solving the constraints we obtain original coordinates in terms of the effective coordinates and momenta. Presence of momenta induces noncommutativity of string endpoints. We show that noncommutativity relations are connected by N=1 supersymmetry transformations and noncommutativity parameters are components of N=1 supermultiplet

Influence of frequency offset on the reception of OFDM/QPSK signal using MBDD algorithm

In this paper we present the basic characteristics of Orthogonal Frequency Division Multiplex (OFDM) systems with quadrature phase shift keying (QPSK) modulation and multi-bit differential detection (MBDD). In the simulation environment designed for this purpose, we analyze the effects of frequency offset on the performances of OFDM digital communications. We also analyze the influence of OFDM system parameters on system performances for various values of frequency offset, number of bits for multi-bit detection and the number of subcarriers. We have shown the advantages and disadvantages of using MBDD in the OFDM systems

A new epigean false scorpion: Roncus sumadijae n. sp. (Neobisiidae, Pseudoscorpiones) from the Balkan Peninsula (Western Serbia)

A new endemic epigean species from the village of Adžina Livada, nr. Kragujevac, Mts. Gledićke Planine, western Serbia, is erected, described and thoroughly illustrated. Its main morphometric characters and important diagnostic features are analyzed and compared to the two closest congeners, Roncus ivanjicae B. Ćurčić, and R. golijae B. Ćurčić from western Serbia, respectively

Copper Electrodeposition onto Palladium from a Deep Eutectic System Based on Choline Chloride

Recently, there has been an increasing interest in developing nonaqueous electrolytes which have been widely employed as an alternative media for a range of metals and metal alloys electrodepositions. A promising and new class of electrolytes among ionic liquids (Ils) are deep eutectic solvents (DESs)1 . The purpose of the copper deposition study from DESs is the application of copper coating and copper alloys in both, industry and fundamental research. In this work, the electrochemical deposition of copper onto palladium working substrate from ChCl/EG (1:2 ratio) DES electrolyte at 50°C was investigated. Additionally, the Cu(II) electroreduction process was studied by potentiodynamic measurements, cyclic voltammetry, chronoamperometry, in the electrolytes with different concentrations of Cu(II) ions ranging from 0.1 M to 0.5 M. The cyclic voltammetry results indicated that the bulk deposition of Cu(II) begins to occur at around –0.080 V vs. Cu. It was found that copper deposition onto the Pd cathode from ChCl:EG electrolyte under potentiostatic conditions is achievable. Data collected from X-ray diffraction (XRD) analysis proved that the cathodic deposits are composed of Cu and CuPd intermetallic. CuPd alloys with different Pd-Cu ratios were prepared by constant potential of –0.100 V vs. Cu from ChCl/EG containing 0.1 M and 0.5 M Cu(II). It is worth noting that the Xray data indicated that the composition of the produced Pd-Cu films could be varied by changing the concentration of Cu(II) ions in the electrolyte or changing the deposition mode

Krpeljska fauna autohtone pramenke u Istočnoj Srbiji

Sheep production is an example of a sustainable production fully integrated within the local rural development. One of the main threats on the outdoor breeding of sheep is parasitism. Ticks are nuisances and vectors of several diseases agents. The distribution of ticks appears to be changing, with spread to previously unaffected areas. Tick and tick-borne disease control is one of the major components of animal health program protecting livestock in the developing countries, which reflects impact on the livelihood of resource-poor farming communities. Taking into consideration the negative impact on the health status of the livestock, also the direct and indirect economic losses, it is necessary to examine the tolerance and resistance of certain species against diseases. It is one of the most important elements of the strategy of selection and screening for resistant animals. The aim of this study was to determine the tick species persisting in 45 tested autochthonous Zackel sheep flocks, and examine their seasonal occurrence from March 2010 to January 2011, in the region of South Serbia. The result showed that Ixodes, Dermacentor, Ripicephalus and Haemaphysalis were the most abundant ticks found, affecting 50.40% tested sheep. The result of this study is a survey of tick species from autochthonous Zackel sheep in Serbia and implication of possible preventions measures for diseases caused and transmitted by ticks.Ovčarstvo predstavlja primer održive proizvodnje koja čini sastavni deo ruralnog razvoja. Jedan od glavnih zdravstvenih problema kod ekstenzivnog načina uzgoja ovaca predstavljaju parazitske infekcije. Krpelji su vektori za uzročnike mnogobrojnih oboljenja. Rasprostranjenost krpelja se menja i u novije vreme ih nalazimo i na novim arealima. U zemljama u razvoju, borba protiv krpelja i oboljenja prenosica krpeljima predstavljaju jedan od glavnih strateških tačaka zdravstvenog nadzora nad životinjama i ljudima. Uzimajući u obzir značaj direktnih i indirektnih ekonomskih gubitaka izazvanih krpeljima i oboljenjima čiji su oni uzročnici, posebna pažnja treba da se posveti ispitivanju tolerancije i otpornosti ka parazitskim bolestima pojedinih vrsta i rasa životinja. Potraga za otpornim jedinkama i njihova selekcija treba da bude deo strategije stočarstva. Cilj ovog rada je bio da prikaže rezultate ispitivanja o prisustvu krpeljske faune u 45 zapata ovaca autohtone pramenke. Ispitana je sezonalna distribucija pojave pojedinih krpelja u periodu između marta 2010. i januara 2011. godine, u regionu Istočne Srbije. Kod 50, 40% ispitanih ovaca ustanovljeno je prisustvo krpelja. Rezultati pokazuju da su krpelji iz rodova Ixodes, Dermacentor, Ripicephalus i Haemaphysalis najučestaliji u zapatima ovaca autohtone pramenke

A twisted look on kappa-Minkowski: U(1) gauge theory

Kappa-Minkowski space-time is an example of noncommutative space-time with potentially interesting phenomenological consequences. However, the construction of field theories on this space, although operationally well-defined, is plagued with ambiguities. A part of ambiguities can be resolved by clarifying the geometrical picture of gauge transformations on the kappa-Minkowski space-time. To this end we use the twist approach to construct the noncommutative U(1) gauge theory coupled to fermions. However, in this approach we cannot maintain the kappa-Poincar\'e symmetry; the corresponding symmetry of the twisted kappa-Minkowski space is the twisted igl(1,3) symmetry. We construct an action for the gauge and matter fields in a geometric way, as an integral of a maximal form. We use the Seiberg-Witten map to relate noncommutative and commutative degrees of freedom and expand the action to obtain the first order corrections in the deformation parameter.Comment: 24 pages, clarifications added, reference list updated, to appear in JHE