Structure-dependent optical properties of Au/Ag irradiated TiN thin films

Titanium nitride (TiN) is an attractive alternative for modern and future photonic applications, as its optical properties can be engineered over a wide spectral range. In this study, we have used sequential implantation of gold and silver ions with varying ion fluence, as well as subsequent annealing, in order to modify the optical and plasmonic properties of TiN thin films and correlated this to their structural properties. Our investigations show that the columnar structure of the TiN films is partially destroyed upon implantation, but metallic Au and Ag nanoparticles are formed. The irradiation further induces a reduction of the lattice constant as well as changes the TiN stoichiometry and grain size. From the optical point of view, the implanted films possess less metallicity with increasing Ag fluence and losses several times lower than the as-deposited film, which can be correlated with the deficiency of nitrogen and additional defects. Subsequent annealing partially recovered the destroyed columnar structure, and the films become more metallic where the optical losses are much smaller in comparison to the as-implanted situation, being comparable to those of pure Au and Ag. In this way, by varying the implantation fluence of silver ions properly while keeping the gold fluence constant, we were able to optimize experimental parameters in such a way to ensure the formation of TiN with desirable optical performances

Enzymatic synthesis of vitamin B6 precursor

3-Cyano-4-ethoxymethyl-6-methyl-2-pyridone is an important precursor in the synthesis of vitamin B6, obtained in the addition reaction between 2-cyanoacetamide and 1-ethoxy-2,4-pentanedione catalyzed by lipase from Candida rugosa (triacylglycerol ester hydrolases, EC 3.1.1.3). This work shows new experimental data and mathematical modeling of lipase catalyzed synthesis of 3-cyano-4-ethoxymethyl-6-methyl-2-pyridone, starting from 1-ethoxy-2,4-pentanedione and 2-cyanoacetamide. Kinetic measurements were done at 50 oC with enzyme concentration of 1.2 % w/v. Experimental results were fitted with two kinetic models: the ordered bi-ter and ping-pong bi-ter model, and the initial rates of the reaction were found to correlate best with a ping-pong bi-ter mechanism with inhibition by 2-cyanoacetamide. Obtained specificity constants indicated that lipase from C. rugosa had higher affinity towards 1-ethoxy-2,4-pentanedione and less bulky substrates. [Projekat Ministarstva nauke Republike Srbije, br. 172013, br. III 46010 and br. 172049

Supplementary information for the article: Milović, M.D., Vasić Anićijević, D.D., Jugović, D., Anićijević, V.J., Veselinović, L., Mitrić, M., Uskoković, D., 2019. On the presence of antisite defect in monoclinic Li2FeSiO4 – A combined X-Ray diffraction and DFT study. Solid State Sciences 87, 81–86. https://doi.org/10.1016/j.solidstatesciences.2018.11.008

Supplementary information for: [https://doi.org/10.1016/j.solidstatesciences.2018.11.008]Related to: [http://dais.sanu.ac.rs/123456789/4552

Novi način formiranja kompozitnih prevlaka

Ni/WC and Cu/WC composite coatings were obtained in two steps. The first step consists of the inert WC particles deposition from the aqueous solution onto steel surface by means of a micro-pipette and covering by the dilute aqueous Nafion solution. The second step is the electrochemical metal deposition from commercial baths in constant current regimes. As result, compact composite coatings were obtained with the different amounts of WC in the deposit in the entire range between a part of a percent up to a few tenths of the percent. The new two-steps method for the formation of the composite coatings renders a very homogeneous distribution of inert WC particles in the deposit and exactly defined chemical composition in each part of the coating Several advantages of splitting the process into two steps are found: the electrolyte for the metal deposition stays clean, no stirring is necessary and it is possible to deposit homogeneously large particles at desired parts of the surface. It is also possible to form multi-layer composite deposits as well as composite foils.Kompozitne prevlake nikal-volframkarbid Ni/WC i bakar-volframkarbid Cu/WC dobijene su iz dva stupnja. Prvi stupanj obuhvata nanošenje inertnih čestica volframkarbida (WC) iz vodenog rastvora mikropipetom na čeličnu površinu. Preko nanetih čestica sipan je razblažen vodeni rastvor nafiona. Drugi stupanj predstavlja elektrohemijsko taloženje metala iz komercijalnih elektrolita pri konstantnom strujnom režimu. Kao rezultat dobijene su kompaktne kompozitne prevlake, gde je količinu WC moguće menjati od dela procenta do nekoliko desetina procenata. Korišćenjem dvostepenog formiranja kompozitnih prevlaka dobija se homogena raspodela inertnih čestica u prevlaci i tačno definisan hemijski sastav u svakom delu prevlake. Prednost ovakvog formiranja kompozitnih materijala je velika, jer ne dolazi do prljanja elektrolita za taloženje osnovnog metala, nije potrebno nikakvo mešanje elektrolita, a moguće je ugraditi velike i teške čestice i to na tačno definisanim mestima na površini. Takođe, moguće je formirati i višeslojne kompozitne prevlake, kao i kompozitne folije

Apparatus for determining the technical characteristics of pumps and compressors

Tehnički razvoj civilizacje uslovljava sve veći broj uređaja i aparata koji nas okružuju a koje najčešće nismo u stanju da suštinski upoznamo principe njihovog rada. Zbog toga se takvi uređaji najčešće nepotpuno ili čak pogrešno koriste odnosno ne koriste se sve u optimalnim parametrima i u svim funkcijama za koje su projektovani. Nepoznavanje suštine rada pumpi i kompresora ima za posledicu da mnogi inženjeri ne znaju da pravilno odaberu tip pumpe i kompresora za pojedine uslove eksploatacije tj. transporta fluida. Posledica lošeg izbora ovih uređaja je povećana potrošnja energije za njihov rad, opterećenje mreže kuda fluid protiče, veliki ili nizak pritisak na željenim tačkama duž instalacije, smanjeno iskorišćenje i dr. Loš izbor takođe povlači nefunkcionalan rad i drugih uređaja koji zavise od rada pumpi i kompresora što za posledicu ima nekvalitetan proizvod ili uslugu koju zbirno ta oprema daje. Iz gore navedenih razloga napravljena je aparatura koja na jednostavan način demonstrira princip rada pumpi i kompresora. Aparatura na jednostavan način vizuelno prezentuje princip rada pumpi i kompresora, i na jednostavan način demonstrira kako se električna energja pretvara u energiju kretanja radnog kola pumpe a potom pretvara u potencijalnu, statičku i dinamičku energiju fluida nad kojim se vrši rad. U ovom radu je pokazano da su izmerene H-Q krive u dobroj saglasnosti sa teorijskom Bernulijevom jednačinom. Na aparaturi se najbolje pokazuje funkcionalnost i primena Bernulijeve jednačine kao i njena detaljna analiza. Aparatura je namenjena svima koji imaju potrebu da se pravilno upoznaju sa tehničkim karakteristikama pumpi i kompresora i kako se te karakteristike mogu izmeriti.The technical development of civilization is conditioned by the increasing number of devices and apparatus that surround us, which we are most often unable to substantially understand the principles of their operation. As a result, such devices are most often incompletely or even incorrectly used, or not all are used in optimal parameters and in all the functions for which they are designed. Unfamiliarity with the essence of the operation of pumps and compressors results in many engineers not knowing how to correctly select the type of pump and compressor for particular operating conditions, ie fluid transport. The consequence of poor selection of these devices is the increased energy consumption for their operation, the load on the network where the fluid flows, the high or low pressure at the desired points along the installation, reduced utilization, etc. Poor selection also entails dysfunctional operation of other devices that depend on the operation of pumps and compressors, resulting in a poor quality product or service provided by that equipment For the above reasons, an apparatus has been made that demonstrates the principle of operation of pumps and compressors in a simple manner. The apparatus visually presents the principle of operation of the pumps and compressors and demonstrates in a simple manner how electricity is converted into the energy of the pump impeller and then converted into the potential, static and dynamic energy of the fluid over which it is operated. This paper shows that the measured H-Q curves are in good agreement with the theoretical Bernoulli equation. The functionality and application of Bernoulli's equation and its detailed analysis are best demonstrated on the apparatus. The apparatus is intended for all those who need to know properly the technical characteristics of pumps and compressors and how these characteristics can be measured

Metal ion-implanted TiN thin films: Induced effects on structural and optical properties

The ion implantation technique has a number of advantages over conventional methods for the improvement of thin films that offer the various possibilities of their use in different industrial and technological fields. Herein, we present the effects of metal ion implantation on the structural and optical properties of TiN thin films. TiN films of 170 nm thickness were grown by d.c. reactive sputtering on Si (100) wafers and then irradiated at 5×1016 ions/cm2 with either Au, Ag, or Cu ions by using two different energies per each implanted metal. The results showed that as deposited TiN crystallizes in form of fcc cubic structure, with the crystallites preferentially oriented along the (111) plane. For all implanted layers the cubic crystallographic structure was preserved, but compared to as deposited TiN the crystallites were smaller and the lattice was contracted. Besides, the surface compositional analysis of as deposited sample showed the coexistence of TiN, TiO2 and TiOxNy phases and this was related to the surface oxidation of the films due to the exposure to air. After implantation, the results were almost similar for all metals, showing an increase in TiO2 contribution and the formation of pure metallic Au and Ag phases, while copper is in the Cu2+ state, which is attributed to Cu(II)-oxide and Cu(OH)2. The microstructural characteristics including defect formation, changes in the crystallite size and lattice contraction, and also growth of different metallic phases during implantations were correlated with the findings of the optical characterization of the implanted films. For as deposited film we found energy gap of 2.91 eV, which was lower than the value typical for TiN. After implantation the gap was shifted to higher energies, while at the visible part of the region, additional energy levels, at photon energies below 2.9 eV were observed. Further, all implanted films showed degraded photocatalytic activity compared to as deposited TiN, among which Cu-implanted samples exhibited the best photocatalytic performances. The lower photocatalytic activity of Au and Ag-implanted films compared to Cu implantations was ascribed to larger structural defects and formation of less favorable electronic states.IX International School and Conference on Photonics : PHOTONICA2023 : book of abstracts; August 28 - September 1, 2023; Belgrad

Approaching the socialist factory and its workforce: considerations from fieldwork in (former) Yugoslavia

The socialist factory, as the ‘incubator’ of the new socialist (wo)man, is a productive entry point for the study of socialist modernization and its contradictions. By outlining some theoretical and methodological insights gathered through field-research in factories in former Yugoslavia, we seek to connect the state of labour history in the Balkans to recent breakthroughs made by labour historians of other socialist countries. The first part of this article sketches some of the specificities of the Yugoslav self-managed factory and its heterogeneous workforce. It presents the ambiguous relationship between workers and the factory and demonstrates the variety of life trajectories for workers in Yugoslav state-socialism (from model communists to alienated workers). The second part engages with the available sources for conducting research inside and outside the factory advocating an approach which combines factory and local archives, print media and oral history

Kompozitne Ni/WC prevlake dobijene elektrohemijskim taloženjem konstantnom i pulsirajućom strujom

The properties of composite coatings are dependent on properties of the base metal, as well as on properties of incorporating particles. The Ni / W composite coatings were obtained by electro deposition from commercially available Vat bath containing additives for brightness and smoothing of the surface and insoluble WC particles. Before the deposition, magnetic mixer was used and rotating disc electrode (RDE) was used for deposition of the composite. It was showed that the amount of WC in the coating could be altered from parts of percent to over 80 percents., as a result of appropriate regime of mixing and deposition. It was also showed that the amount of insoluble WC in Vat bath had no significant influence on the amount of WC in the coating.Osobine kompozitnih prevlaka zavise od osobina osnovnog metala koji čini kompozit, kao i osobina čestica koje se ugrađuju. Kompozitne prevlake nikal-volframkarbid dobijene su elektrohemijskim taloženjem iz komercijalnog, Vatovog elektrolita za taloženje osnovnog metala nikla, koji sadrži dodatke za sjaj i poravnavanje površine i nerastvornih čestica volframkarbida. Za mešanje elektrolita korišćena je magnetna mešalica (pre taloženja), a za taloženje kompozita korišćena je rotirajuća disk elektroda RDE. Kao rezultat dobijeno je da pri odgovarajućem režimu taloženja i mešanja elektrolita količinu volframkarbid u prevlaci je moguće menjati od dela procenta do preko osamdeset procenata. Takođe, dobijeno je da korišćenjem RDE i magnetne mešalice sadržaj volframkarbida u Vatovom elektrolitu пeтa veliki uticaj na sadržaj volframkarbida и prevlaci

Kompozitne Ni/WC prevlake dobijene elektrohemijskim taloženjem konstantnom i pulsirajućom strujom

The properties of composite coatings are dependent on properties of the base metal, as well as on properties of incorporating particles. The Ni / W composite coatings were obtained by electro deposition from commercially available Vat bath containing additives for brightness and smoothing of the surface and insoluble WC particles. Before the deposition, magnetic mixer was used and rotating disc electrode (RDE) was used for deposition of the composite. It was showed that the amount of WC in the coating could be altered from parts of percent to over 80 percents., as a result of appropriate regime of mixing and deposition. It was also showed that the amount of insoluble WC in Vat bath had no significant influence on the amount of WC in the coating.Osobine kompozitnih prevlaka zavise od osobina osnovnog metala koji čini kompozit, kao i osobina čestica koje se ugrađuju. Kompozitne prevlake nikal-volframkarbid dobijene su elektrohemijskim taloženjem iz komercijalnog, Vatovog elektrolita za taloženje osnovnog metala nikla, koji sadrži dodatke za sjaj i poravnavanje površine i nerastvornih čestica volframkarbida. Za mešanje elektrolita korišćena je magnetna mešalica (pre taloženja), a za taloženje kompozita korišćena je rotirajuća disk elektroda RDE. Kao rezultat dobijeno je da pri odgovarajućem režimu taloženja i mešanja elektrolita količinu volframkarbid u prevlaci je moguće menjati od dela procenta do preko osamdeset procenata. Takođe, dobijeno je da korišćenjem RDE i magnetne mešalice sadržaj volframkarbida u Vatovom elektrolitu пeтa veliki uticaj na sadržaj volframkarbida и prevlaci

Hydrophilic gel containing coenzyme Q 10 -loaded liposomes: Preparation, characterization and stress stability tests

The aim of this study was to develop a semisolid formulation containing liposomes loaded with coenzyme Q10 (Q10). Q10-loaded liposome dispersion prepared from non-hydrogenated lecithin and characterized for particle size, polydispersity index (PDI), pH value and Q10-content was incorporated into carbomer gel, and a liposome gel was obtained. Liposome gel and liposome-free gel were analyzed for flow properties by continuous rheology measurements, pH values and Q10-content, 48 h after preparation and after a temperature stress test (1 cycle: 24 h at 4 o C, 24 h at 20±2 o C and 24 h at 40 o C), in order to predict their long-term stability. Liposomes were identified in liposome dispersion and liposome gel by freeze fracture electron microscopy (FFEM), while their particle size, PDI and zeta potential were determined by photon correlation spectroscopy (PCS). Q10-loaded liposomes were of small particle size (125 nm), homogeneous (PDI=0.2) and negatively charged, and their incorporation into the gel did not significantly change (p&0.05) their particle size and PDI. FFEM confirmed liposomes presence in the liposome gel. Liposome and liposome-free gel revealed non-Newtonian, shear-thinning plastic flow behavior. The temperature stress test revealed that temperature changes did not significantly influence (p&0.05) the pH value, while they significantly decreased (p&0.05) Q10-content in gels. Q10 was significantly more stable (p&0.05) in liposome gel than in liposome-free gel. Rheological parameters of liposome-free gel significantly changed, in contrast to the liposome gel. In conclusion, Q10-loaded liposome gel suitable for dermal use was developed, exhibiting high stability even after subjecting to the temperature stress test