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EN
In this paper, soluble starch was studied as a depressant of hematite during flotation separation of apatite using sodium oleate as a collector. Surface charge measurement, soluble starch adsorptions, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to understand the interaction mechanisms between minerals (hematite and apatite) and soluble starch. The results indicated that chemical interaction between hematite and soluble starch was present, and supported the bonding of hydroxyl, while physical adsorption of soluble starch molecules with apatite occurred. Results of micro-flotation studies suggested that soluble starch was considered as a selective depressant for hematite. The maximum recovery difference between hematite and apatite of 77.5% was obtained with 40 mg/dm3 soluble starch. The flotation experiment results of natural iron ore showed that flotation indexes with 59.73% Fe, iron recovery of 81.5% and 75.68% of dephosphorization ratio were achieved at a soluble starch dosage of 60 mg/dm3. However, a higher dosage of soluble starch addition caused the difficulty for flotation separation of apatite from hematite. Our results provided theoretical basis for the flotation separation of apatite from iron oxide ores.
EN
In this work, low rank coal was used for the removal of nonylphenol ethoxylate with fifteen ethylene oxide groups (NPEO15) from aqueous solutions at different contact times, temperatures, and initial adsorbent concentrations. The adsorption isotherms showed good fit with the Langmuir equation. Maximum adsorption capacities calculated at 308, 318, and 328 K were 23.64, 29.41, and 35.71 mg g–1, respectively. The changes in the free energy of adsorption (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) were calculated in order to predict the nature of adsorption. The results of the thermodynamic analysis indicated that a spontaneous process took place, driven synergistically by both enthalpy and entropy. The adsorption kinetics of NPEO15 were consistent with a pseudo-second order reaction model. XPS results showed that the oxygen functional groups on the low rank coal surface were significantly covered by NPEO15. Furthermore, while the content of C–C/C–H functional groups increased significantly, that of C–O functional groups decreased after absorption. These results clearly indicate that low rank coal is more hydrophobic and displays better floatability.
EN
Layered magnetic heterostructures are very promising candidates in spintronics in which the influences of interfaces, surfaces and defects play a crucial role. X-ray photoelectron spectroscopy (XPS) study has been performed for studying in detail the chemical state and electronic structure of Co2FeAl (CFA) Heusler alloy interfaced with Si substrates. XPS survey scan spectra have clearly shown the presence of Fe, Co and Al signal along with the signal due to Si. The presence of Co, Fe and Al signal confirms the formation of CFA alloy phase. Our XPS results support our previous study [1] on CFA/Si structure in determining the magnetic and transport properties across the interface.
EN
Surface changes in naturally occurring metal sulphides (pyrite, arsenopyrite, sphalerite, chalcopyrite, galena and molybdenite) due to the treatments from high – power electromagnetic pulses (HPEMP) at varying times were studied using XPS. Analysis of the obtained results revealed common patterns and differences in surface transformations. The transformations were found to include two main stages. The first stage were observed at low treatment intensities (up to N ~ 103 pulses). At this stage formation and accumulation in the surface layer of the nonstoichiometric sulphide phase, oxides and hydroxides, as well as elemental (polysulfide) sulphur and / or metastable sulphur species (thiosulfate, sulphite) were observed. The second stage (N ≥ 3 · 103 pulses) is characterized by the removal of sulphur species and renewal of the mineral surface (sulfidization). The application of HPEMP treatment to improve flotation selectivity is supported by single-mineral flotation tests. Changes in floatability as a result of HPEMP treatment are principally explained by surface phase changes.
PL
Zmiany powierzchni w naturalnie występujących siarczkach metali (piryt, arsenopiryt, sfaleryt, chalkopiryt, galena i molibdenit) w wyniku obróbki impulsami elektromagnetycznymi o dużej mocy (HPEMP) w różnym czasie badano przy użyciu XPS. Analiza uzyskanych wyników ujawniła typowe wzory i różnice w transformacjach powierzchniowych. Stwierdzono, że transformacje obejmują dwa główne etapy. Pierwszy etap obserwowano przy niskiej intensywności działania impulsami (do N ~ 103 impulsów). Na tym etapie zaobserwowano tworzenie i akumulację w warstwie powierzchniowej niestechiometrycznej fazy siarczkowej, tlenków i wodorotlenków, a także siarki elementarnej (polisiarczkowej) i / lub metastabilnej (tiosiarczan, siarczyn). Drugi etap (N ≥ 3 · 103 impulsów) charakteryzuje się usuwaniem rodzajów siarki i odnawianiem powierzchni mineralnej (siarczkowanie). Zastosowanie obróbki HPEMP w celu poprawy selektywności flotacji jest poparte testami flotacji pojedynczych minerałów. Zmiany flotowalności w wyniku obróbki HPEMP są wyjaśnione zmianami fazy powierzchniowej.
EN
Tungsten trioxide (WO3) thin films were prepared by thermal evaporation technique on thoroughly cleaned glass substrates at high pressure of 133.322 mPa in presence of argon. The substrate temperature was maintained from 6 °C to 8 °C with the help of a cold jar. The deposited films were annealed at 400 °C in air for about 2 hours. The films were characterized in terms of their composition by X-ray photoelectron spectroscopy. Subsequently, the laboratory developed dry lithiation method was used to intercalate lithium atoms into as-deposited films in various proportions. With the amount of lithium content inserted into the film, the films showed coloration in visible and near infrared regions. The morphology, coloration efficiency and optical constants of annealed and lithiated films were calculated.
EN
The X-Ray photoelectron spectrometry was applied to elucidate an impact of iron(II), tin(II) and manganese(II) sulphates on cement hydration. Iron(II) sulphate, most commonly added as a reducer of Cr(VI) to Cr(III) on cement grinding, was taken as a reference. The tin(II) and manganese(II) sulphates could be potentially used as reducers of Cr(VI) too. However, the tin(II) sulphate has very strong retarding action on cement setting. In order to find out the relevant mechanisms, the main component of Portland cement - alite (solid solution of tricalcium silicate) was used as a model material. The hydrated alite samples were subjected to the X-ray photoelectron studies to identify the surface products responsible for retarding effects. These products appeared to be quite different in the presence of particular sulphate admixtures. The formation of a Ca-Sn containing compound has been proved directly.
PL
W pracy badano wpływ siarczanów żelaza(II), manganu i cyny stosowanych w roli reduktorów Cr(VI) na proces wiązania i twardnienia cementu. W celu wyjaśnienia obserwowanych zjawisk przeprowadzono badania z udziałem alitu traktowanego jako uproszczony model cementu. Postęp hydratacji śledzono metodą mikrokalorymetryczną i stwierdzono silnie opóźniające działanie siarczanu cyny. W celu określenia w sposób bezpośredni przyczyny zahamowania hydratacji przeprowadzono badania metodą spektroskopii fotoelektronów, która daje możliwość detekcji produktów utworzonych na powierzchni hydratyzującego materiału; produkty te są różne w przypadku poszczególnych siarczanów. W ten sposób potwierdzono bezpośrednio obecność związku cyny i wapnia w warstwie powierzchniowej, stanowiącej barierę hamującą proces hydratacji w stadium początkowym.
PL
Przedstawiono analizę możliwości wykorzystania styropianów EPS i XPS jako izolacji termicznej dla płyt fundamentowych w domach energooszczędnych wraz z oceną ekonomiczną omawianego rozwiązania. Przedstawiono parametry wytrzymałościowe styropianów, wyniki obliczeń statycznych i analizy ekonomicznej 3 modeli budynków i 3 wariantów rozwiązań izolacji.
EN
The authors have presented analysis of possibilities of using EPS/XPS Styrofoam for lost formwork for slab foundations in sustainable buildings including economic analysis of capital expenditure and operating expenses. The strength parameters of Styrofoam, the results of static calculation and economic analysis for 3 building models and 3 variants of insulation solutions were presented.
EN
Low temperature plasma (LTP) processing technology was successfully applied to modify cashmere fibres and three kinds of assemblies were formed, i.e., weak-treated, optimised-treated and severe-treated ones. Treatment parameters were optimised in terms of the tensile behaviour, friction effect, wettability and touch feeling of cashmere without major modification of the properties inside the fibre. Detailed characterisation was performed to investigate the surface morphologies and chemical compositions of plasma-induced fibres. SEM demonstrates different minor etching effects of the treated cashmere fibres. XPS results indicate a significant increase in surface concentrations of O and N, and an obvious decrease in C after different LTP treatments as a whole. The C-H/C-C non-polar bonds were reduced and C-O/C-N, C = O polar groups were remarkably increased on the cashmere surface after plasma modification. In addition, a carboxyl group (O-C = O) formed. It is found that oxygen-containing bonds, namely, C-O/C-N, C = O and O-C = O, are responsible for the hydrophilic properties of cashmere.
PL
W pracy przedstawiono modyfikację włókien kaszmirowych przy zastosowaniu niskotemperaturowej plazmy (LTP). Zastosowano trzy intensywności obróbki. Parametry obróbki zostały zoptymalizowane pod kątem uzyskania odpowiednich właściwości włókien tj. wytrzymałość na rozciąganie, odporność na tarcie, zwilżalność i chwyt. Za pomocą SEM i XPS dokonano szczegółowej charakterystyki morfologii powierzchni i składu chemicznego włókien poddanych działaniu plazmy. Stwierdzono że obróbka plazmą niskotemperaturową może powodować pogorszenie chwytu wyrobu końcowego, z tego powodu produkty poddawane obróbce plazmą należy poddawać dodatkowym obróbkom przemysłowym, takim jak np. zmiękczanie.
EN
A single pulse of 2.0 to 3.5 kJ of input energy from a 450 mF capacitor was applied to a commercially pure Ti rod in a N2 atmosphere. The surface of the Ti rod transformed from TiO2 into titanium nitride in times as short as 159 msec, providing a bimodal morphology of the cross-section. A much higher value of hardness that was observed at the edge of the cross-section was attributed to nitrogen-induced solid-solution hardening that occurred during the electrical discharge process. The activation energy (Ea) for the diffusion process was estimated to be approximately 86.9 kJ/mol. Results show that the electrical discharge process is a possible potential method for the nitriding of Ti; advantages include a short processing time and control of the nitrided layer without dimensional changes.
11
Content available remote Colossal dielectric constant of NaNbO3 doped BaTiO3 ceramics
EN
BaTiO3 ceramics doped with 0.40 mol% NaNbO3 were prepared using a traditional approach by sintering at temperature of 1250 ºC to 1290 ºC. The prepared ceramics was characterized by very good dielectric properties, such as high dielectric constant (1.5 × 105), low dielectric loss (0.1), and good dielectric temperature stability in the −40 ºC to 100 ºC range for the sample sintered below 1270 ºC. The dielectric characteristics obtained with XPS confirmed that Ti4+ ions remain in the state without any change. The huge increase in dielectric constant in NaNbO3 doped BaTiO3 samples occurs when large amount of Ba2+ ions are excited to a high energy bound state of Ba2+ − e or Ba+ to create electron hopping conduction. For samples with the content of NaNbO3 higher than 0.40 mol%, or sintering temperature higher than 1280 ºC, compensation effect is dominated by cation vacancies with sharply decreasing dielectric constant and increased dielectric loss. The polaron effect is used to explain the relevant mechanism of giant dielectric constant appearing in the ferroelectric phase.
EN
PLA knitted fabric was treated with sodium carbonate in the presence of non-ionic detergent at various concentrations and temperatures in a short liquor bath. The scoured fabric was subsequently treated with industrially important bleaching agents such as hydrogen peroxide, sodium chlorite and sodium hypochlorite at various levels of concentration and pH. The bleached PLA fabric was then evaluated in terms of surface and bulk properties. The structural damage was assessed in terms of tensile strength, while the surface morphology was investigated using scanning electron microscopy (SEM). The surface chemistry of PLA was studied using infra-red (IR) and x-ray photoelectron spectroscopies (XPS). The alkaline-oxidative conditions were deleterious to the integrity of PLA polymer at high temperature, while at low temperature there was a little damage. The acidic-oxidative conditions did not appreciably affect bulk or surface properties even at high temperature.
PL
Dzianiny wykonane z PLA poddano obróbce węglanem sodu w obecności niejonowych detergentów przy rożnych stężeniach i temperaturach. Dzianiny były równocześnie poddane działaniu przemysłowo ważnych środków bielących, takich jak: nadtlenek wodoru, chloryn sodu i podchloryn sodu przy rożnych poziomach stężenia i pH. Bielone dzianiny PLA były następnie oceniane biorąc pod uwagę właściwości powierzchni i wnętrza. Strukturalne uszkodzenia wewnętrzne były oceniane poprzez wytrzymałość na rozciąganie, podczas gdy morfologię powierzchni badano za pomocą SEM. Powierzchnie dzianin PLA badano również stosując spektrofotometrie IR i XPS. Działanie środków alkalicznych i utleniających miało wpływ uszkadzający na integralność polimeru PLA przy wyższych temperaturach, podczas gdy przy niskich temperaturach uszkodzenia były niewielkie.
EN
Purpose: Degradation processes of metallic biomaterials in the oral cavity limit the stability and reliability of dental materials. The influence of environment bacteria Desulfotomaculum nigrificans sulfate reducing bacteria on the corrosion processes of Co-Cr-Mo and Ti-6Al-4V alloys was assessed. Methods: After 28 and 56 days of contact of the materials with the bacterial environment, the surfaces of the tested biomaterials were observed by means of confocal scanning laser microscopy (CSLM), and their chemical composition was studied using X-Ray Photoelectron Spectrometry (XPS). Results: Corrosive changes and the presence of sulfur (with medium atomic concentration of 0.5% for Co-Cr-Mo and 0.3% for Ti-6AL-4V) were observed on the surface of the biomaterials. Image analysis conducted using APHELION software indicated that corrosion pits took up approx. 2.3% and 1.8% (after 28 days) and 4.2% and 3.1% (after 56 days) of the total tested surfaces of cobalt and titanium alloys respectively. The greatest number of corrosion pits had a surface area within the range of 1-50 m2. They constituted from 37% until 83% of all changes, depending on the type of material. Conclusions: An evident influence of the SRB on the cobalt and titanium alloys surfaces was observed. Significant corrosive losses caused by the activity of micro-organisms were stated on the studied metallic surfaces. The results of this study have much cognitive and utilitarian significance.
EN
PtSn/Al2O3 &enspcatalysts with a given loading of 1 wt% Pt and 1 wt% Sn were prepared by co-impregnation or successive impregnation with aqueous solutions of Pt, Sn precursors and a commercial alumina. The catalysts were characterized by N2 &enspadsorption, H2-TPR (H2&ensp temperature-programmed reduction), H2-pulse chemisorption, XPS (X-ray photoelectron spectroscopy) and CO-FTIR (Fourier transform infrared spectroscopy), and tested in the hydrogenation of acetic acid. The results showed that the preparation method affected both the chemical properties and their performance in the hydrogenation of acetic acid. Sn enrichment on the catalysts surface was observed on the co-impregnated catalyst and catalyst in which the Pt precursor had been loaded first. It was found that the modification of Pt was a function of the sequence of Sn addition as revealed by CO-FTIR. Co-impregnated catalyst showed the highest activity and ethanol selectivity.
EN
Surface property plays a very important role on coal hydrophobicity which determines flotation behavior of fine coals. However, coal spontaneous combustion makes coal suffer both oxidation and high temperature heating processes. Coals from the outside of coal piles primarily suffer oxidation (or combustion process) while coals from the inside of coal piles primarily suffer high temperature heating process. It is necessary to investigate the changes in surface properties of coal before and after high temperature heating process. In this investigation, X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), surface area (BET) and contact angle measurements were used to indicate the changes in surface properties of anthracite coal before and after high temperature heating process. Throughout this study, surface properties of coal changed significantly after high temperature heating process. Meanwhile, coal hydrophobicity can be also reduced after high temperature heating.
EN
An additional recovery of coking coal middlings can be utilized for increasing of the concentrate yield of coking coal. A combined flow sheet of comminution and flotation can realize this target. To investigate the effect of grinding process on further flotation of ground products, progressive release flotation tests were used to compare with the float-sink tests, which were regarded as a criterion. Coal middlings were ground by wet-milling with iron balls to <0.5 mm. Curves of ash vs. cumulative yields of sized products indicated that the concentrate yield of coal separated by progressive release flotation was lower than that of coal benefited by the float-sink test, with the same ash for four size fractions (0.5-0.25 mm, 0.25-0.125 mm, 0.125-0.074 mm and <0.074 mm). Distributions of elements conducted by energy disperse spectroscopy (EDX) showed that associated kaolinite was liberated and exposed on the surface. It led to the shift of local surface property from hydrophobicity to hydrophilicity. Meanwhile, analyses of chemical property performed by an X-Ray photoelectron spectrometer (XPS) depicted that the hydrophilic mineral FeOOH, which generated in the grinding process, was adsorbed on the coal surface. Flotation of the ground products were worsened due to the increase of hydrophilicity of the coal surface.
EN
Natural weathering processes can make coal surface more hydrophilic due to the increase of content of hydrophilic functional groups (C-O, C=O, and COOH) and the decrease of content of hydrophobic functional groups (C-C and C-H) on coal surface, and hence the flotation recovery of fine coal is reduced. In this paper, a series of flotation tests were conducted in order to investigate the changes in the flotation kinetic of bituminous coal before and after natural weathering processes. Additionally, XPS was used to indicate the changes in surface properties of bituminous coal. In the investigations the flotation kinetic was changing. The classical first-order rate constant (k) of bituminous coal flotation was reduced after the natural weathering processes. A relationship between the classical first-order rate constant (k) and the hydrophilicity ability (HA) was given.
EN
Cr-free conversion coatings were deposited from a bath containing: titanium(III) chloride, fluorosilicic acid, hydrogen peroxide and oxalic acid. An XPS analysis of the coating deposited for 3 min showed titanium to be present mainly at the +4 oxidation state number and zinc at the +2 oxidation state number, in the form of oxides and hydroxides. Silicon forms silicates. DC polarization showed that the corrosion current densities for the coatings deposited for 30 s – 6 min were below 1 μA·cm−2 and lower than that of zinc coating. EIS and neutral salt spray test revealed that in order to ensure good protective properties deposition should be conducted for at least 3 minutes.
PL
Bezchromowe powłoki konwersyjne otrzymano z kąpieli zawierającej: chlorek tytanu(III), kwas fluorokrzemowy, nadtlenek wodoru oraz kwas szczawiowy. Analiza XPS powłoki osadzanej przez 3 minuty wykazała obecność tytanu na +4 stopniu utlenienia oraz cynku w formie utlenionej, zarówno pod postacią tlenków jak i wodorotlenków. Na podstawie pomiarów polaryzacyjnych stałoprądowych obliczono szybkość korozji w 0.5 M NaCl powłok osadzanych w zakresie 30 s do 6 min, która była niższa od 1 μA·cm−2 oraz niższa od szybkości korozji porównawczej powłoki cynkowej. Badania zmiennoprądowe metodą EIS oraz test w komorze solnej pozwoliły stwierdzić, że dobre właściwości ochronne posiadają powłoki bezchromowe osadzane przez przynajmniej 3 minuty.
PL
W artykule przedstawiono skład chemiczny warstwy powierzchniowej i objętościowej wełny szklanej i skalnej. Analizy zostały przeprowadzone przy użyciu dwóch metod instrumentalnych (nieinwazyjnych technik), rentgenowskiej analizy fluorescencyjnej (XRF, X-Ray Fluorescence) i rentgenowskiej spektrometrii fotoelektronów (XPS, X-Ray Photoelectron Spectroscopy). Zaobserwowano, że skład wełny szklanej i skalnej jest zróżnicowany. Charakteryzuje się on zawartością głównych tlenków, takich jak SiO2, Al2O3, CaO, MgO oraz Fe2O3. Analizowane wełny mineralne są materiałami o złożonym składzie chemicznym, a użyte metody spektroskopowe w dobrym stopniu odzwierciedlają ich główne składniki. Wykazano przewagę rentgenowskiej analizy fluorescencyjnej (XRF) nad metodą XPS, oraz ich wzajemną komplementarność.
EN
Chemical composition of glass wool and stone wool has been investigated. Researches were carried out by using two analytical techniques, X-ray fluorescence analysis (XRF) and X-ray photoelectron spectroscopy (XPS). The both methods are non-destructive. It was observed that composition of the glass wool and stone wool is variable, but it characterizes by the content of the main oxides as SiO2, Al2O3, CaO, MgO, and Fe2O3. Analyzed wool samples are materials having complex chemical composition, and used spectroscopic methods in good extent reflect their main ingredients. It has been demonstrated the advantage of XRF method over the use of XPS technique, and their mutual complementarity.
20
Content available remote XPS analysis of AISI 304L stainless steel surface after electropolishing
EN
In the paper, the passive surface layers of AISI 304L after standard (EP50) and very-high-current density electropolishing (EP1000) in a mixture of orthophosphoric and sulfuric acids in a 1:4 ratio, are presented. The main finding of the presented studies is enrichment of the steel surface film in chromium: total chromium to total iron ratio was equal to 6.6 after EP50 and to 2.8 after EP1000; on the other hand, chromium compounds to iron compounds ratio was equal to 10.1 after EP50, and 3.9 after EP1000.
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