X-ray photoelectron spectroscopy of low surface concentration mass-selected Ag clusters

2000 ◽  
Vol 113 (20) ◽  
pp. 9233-9238 ◽  
Author(s):  
James N. O’Shea ◽  
Joachim Schnadt ◽  
Staffan Andersson ◽  
Luc Patthey ◽  
Steffen Rost ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Concentration ◽  
X Ray ◽  
Ag Clusters

Effect of Phosphorus on the Friction and Wear Characteristics of Cu-Sn-P Alloys

1979 ◽  
Vol 101 (2) ◽  
pp. 201-206 ◽  
Author(s):  
Y. Taga ◽  
K. Nakajima
Keyword(s):  
Photoelectron Spectroscopy ◽  
Friction And Wear ◽  
Structural Changes ◽  
Surface Concentration ◽  
Wear Characteristics ◽  
X Ray ◽  
The Matrix ◽  
Pin On Disc ◽  
The Coefficient Of Friction ◽  
Friction And Wear Characteristics

The effects of phosphorus on the friction and wear characteristics of Cu-5 at. percent Sn-P alloys containing 1–5 at. percent P were studied using a pin on disc apparatus. The results showed that the decrease in both the coefficient of friction and the rate of wear became conspicuous with the increase in quantity of Cu3P coexisting in the matrix; its amount increases with the content of phosphorus. The structural changes in the surface of the specimen due to heating in a vacuum were observed by using Auger electron spectroscopy and X-ray photoelectron spectroscopy. It was seen that the surface concentration of phosphorus strongly increased after heating at 573K, whereas the diffusion of tin atoms was markedly retarded. It was concluded from these results that the behavior of phosphorus atoms in the surface during sliding played an important role in the friction and wear characteristics of Cu-Sn-P alloys.

scholarly journals Poly(styrene/acrolein) and poly(styrene/α-tert-butoxy-ω- vinylbenzyl-polyglycidol) microspheres. Similarities and differences

e-Polymers ◽  
2002 ◽  
Vol 2 (1) ◽  
Author(s):  
Teresa Basinska
Keyword(s):  
Photoelectron Spectroscopy ◽  
Particle Surface ◽  
Surface Concentration ◽  
Covalent Immobilization ◽  
Maximal Surface ◽  
Polystyrene Microspheres ◽  
Surface Layers ◽  
X Ray ◽  
Surface Fraction ◽  
Model Protein

AbstractProperties of two types of polystyrene microspheres with polyacrolein and polyglycidol components in their surface layers are compared. Microspheres were prepared in batch radical emulsifier-free emulsion copolymerizations of styrene with acrolein and/or α-tert-butoxy-ω-vinylbenzyl-polyglycidol macromonomer ( Mn̅ = 2700). Polymerizations were initiated with potassium peroxodisulfate, and the ratio of initial concentrations of styrene and initiator was constant. Number average diameters of poly(styrene/acrolein) (P(S/A)) and of poly(styrene/polyglycidol) (P(S/PGL)) particles were in the range of 200 - 650 nm and decreased with increasing concentration of acrolein and/or polyglycidol in the polymerizing mixtures. The diameter polydispersity of synthesized particles ( Dw ̅ /Dn̅) was usually lower than 1.02. X-ray photoelectron spectroscopy for P(S/A) and P(S/PGL) microspheres showed that surface layers of particles were significantly enriched in polyacrolein or polyglycidol segments, surface fractions of which increased with increasing concentration of the more hydrophilic comonomer in the polymerizing mixture. In the case of P(S/A) particles, the maximal fraction of polyacrolein approached 80 mol-%, whereas for P(S/PGL) particles the maximal surface fraction of PGL was 42 mol-%. Human serum albumin was used as a model protein for studies of attachment onto P(S/A) and P(S/PGL) microspheres. It has been found that for both kinds of particles, the maximal surface concentration of attached (adsorbed and/or covalently immobilized) protein decreased with increasing fraction of hydrophilic component in the particle surface layer (polyacrolein or polyglycidol units). In the case of P(S/A) particles, adsorption always accompanied covalent immobilization of proteins. To the contrary, covalent immobilization of proteins onto the P(S/PGL) microspheres proceeded without adsorption of proteins.

A highly active K/Cu-Mn-O catalyst for the removal of nitric oxide in indoor air

2017 ◽  
Vol 28 (1) ◽  
pp. 7-16 ◽  
Author(s):  
Chan Wang ◽  
Feng Li ◽  
Zishu Sun ◽  
Qijun Song
Keyword(s):  
Nitric Oxide ◽  
Indoor Air ◽  
Photoelectron Spectroscopy ◽  
Elimination Rate ◽  
Surface Concentration ◽  
Precipitation Method ◽  
X Ray ◽  
Highly Active ◽  
Metal Nitrates ◽  
Co Precipitation

Nitric oxide is a frequently encountered pollutant in indoor air. It could have a number of harmful effects on human health even at low concentration. Aiming to improve the indoor air quality, an environment-friendly method was developed for the elimination of nitric oxide at ppm level based on a low temperature effective catalyst potassium-doped copper–manganese oxide (K/Cu-Mn-O). The catalyst was obtained through a co-precipitation method using metal nitrates in aqueous solution and the precipitate was calcinated at 400℃ for 5 h. After impregnation with K, the best catalytic activity was observed for the K/Cu-Mn-O catalyst with a Cu/Mn ratio of 1:2 and surface concentration of doping K 7.03% (7.4 mg/g). The composition and the structure of the catalyst were comprehensively characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and Brunauer–Emmett–Teller. The results showed that the potassium doping improved the adsorption ability of catalyst, and promoted the formation of the nitrate salt, and thereby further improved the elimination rate of nitric oxide. Finally, the possible reaction mechanisms are discussed.

Radiation-Enhanced Aqueous Dissolution of Minerals

2011 ◽  
Vol 1298 ◽  
Author(s):  
Catherine A. Dukes ◽  
Raúl A. Baragiola
Keyword(s):  
Photoelectron Spectroscopy ◽  
Ion Irradiation ◽  
Water Immersion ◽  
Surface Concentration ◽  
Mineral Surface ◽  
X Ray ◽  
Water Exposure ◽  
Humid Environment ◽  
Water Ph ◽  
Dissolution Of Minerals

ABSTRACTMineral samples of varying petrology, exposed to ion irradiation and subsequently immersed in water or exposed to a humid environment, show up to 60% depletion of specific surface atoms (Mg, Ca, K, and Na) — a depletion that is enhanced 26,000x compared to unirradiated surfaces. Surface depletions of irradiated minerals exposed to water were measured using X-ray photoelectron spectroscopy. Irradiations were performed with 4 keV Ar+ ions at fluences from 1014 – 1019 ion cm-2; samples were subsequently exposed to liquid water or humid air (35º C and 70% RH). Analyses were done before irradiation, after irradiation, and after exposure to water, allowing identification of changes in composition due solely to ion irradiation or combined with water exposure. Before water exposure, we observe no significant change in stoichiometry of the minerals for ion fluences <1018 ions cm-2. We find incongruent depletion of 60% Mg for forsterite after exposure to humidity or three minutes (or more) water immersion. Augite undergoes reduction in the surface concentration of approximately 30% Mg, 40% Ca, and 55% Na after 1.9 x 1017 Ar cm-2 and immersion in HPLC water (pH: 6.8) for three minutes. Depth profiles of the irradiated, water exposed, minerals show that the depth of the depleted region is on the order of the ion range, ~15nm. In addition, preliminary results for albite, anorthoclase, and microcline in water show significant depletions of Na, Na and K, and K, respectively, from the mineral surface.

Cell Adhesion to Ion Implanted Titanium

1987 ◽  
Vol 110 ◽  
Author(s):  
K. S. Grabowski ◽  
C. R. Gossett ◽  
F. A. Young ◽  
J. C. Keller
Keyword(s):  
Photoelectron Spectroscopy ◽  
Culture Medium ◽  
Preliminary Investigation ◽  
Surface Concentration ◽  
X Ray ◽  
Commercially Pure ◽  
Fibroblast Adhesion ◽  
Tissue Culture Plate ◽  
Elastic Backscattering ◽  
Ion Implanted

AbstractThis preliminary investigation evaluates the influence of ion implantation on tissue adhesion by measuring the tendency of fibroblasts to attach to the surface of ion implanted Ti. For this work, polished specimens of commercially pure Ti were implanted with ions of Ti, Ca, C, or N to produce a surface concentration of the implanted element up to about 25 at. %. Unimplanted and ASTM treated Ti, and tissue culture plate specimens were prepared as controls. Specimens were sterilized, then exposed for 15 min. to a culture medium containing about 100,000 fibroblasts. The solution and loose fibroblasts were rinsed away and the fibroblasts counted to determine those left attached. The influence of the different implantation protocols on fibroblast adhesion to Ti will be described. Analysis of the structure and composition of the ion implanted surfaces was obtained by scanning electron microscopy, x-ray photoelectron spectroscopy, and elastic backscattering spectrometry of energetic He ions.

scholarly journals Removal of Phenolic Compounds from Water Using Copper Ferrite Nanosphere Composites as Fenton Catalysts

Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 901 ◽  
Author(s):  
Carlos Moreno-Castilla ◽  
María Victoria López-Ramón ◽  
María Ángeles Fontecha-Cámara ◽  
Miguel A. Álvarez ◽  
Lucía Mateus
Keyword(s):  
Electron Microscopy ◽  
Catalytic Activity ◽  
Photoelectron Spectroscopy ◽  
Magnetic Measurements ◽  
Surface Concentration ◽  
Copper Ferrite ◽  
Electronic Effects ◽  
X Ray ◽  
Toc Removal ◽  
Cu Ions

Copper ferrites containing Cu+ ions can be highly active heterogeneous Fenton catalysts due to synergic effects between Fe and Cu ions. Therefore, a method of copper ferrite nanosphere (CFNS) synthesis was selected that also permits the formation of cuprite, obtaining a CFNS composite that was subsequently calcined up to 400 °C. Composites were tested as Fenton catalysts in the mineralization of phenol (PHE), p-nitrophenol (PNP) and p-aminophenol (PAP). Catalysts were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and magnetic measurements. Degradation of all phenols was practically complete at 95% total organic carbon (TOC) removal. Catalytic activity increased in the order PHE < PNP < PAP and decreased when the calcination temperature was raised; this order depended on the electronic effects of the substituents of phenols. The as-prepared CFNS showed the highest catalytic activity due to the presence of cubic copper ferrite and cuprite. The Cu+ surface concentration decreased after calcination at 200 °C, diminishing the catalytic activity. Cuprite alone showed a lower activity than the CFNS composite and the homogeneous Fenton reaction had almost no influence on its overall activity. CFNS activity decreased with its reutilization due to the disappearance of the cuprite phase. Degradation pathways are proposed for the phenols.

Structural and physicochemical surface properties of Serratia marcescens strains

1992 ◽  
Vol 38 (10) ◽  
pp. 1033-1041 ◽  
Author(s):  
Henny C. Van der Mei ◽  
Marjorie M. Cowan ◽  
Michel J. Genet ◽  
Paul G. Rouxhet ◽  
Henk J. Busscher
Keyword(s):  
Infrared Spectroscopy ◽  
Zeta Potential ◽  
Cell Surface ◽  
Serratia Marcescens ◽  
Photoelectron Spectroscopy ◽  
Surface Concentration ◽  
Structural Features ◽  
Contact Angles ◽  
X Ray ◽  
Zeta Potentials

Serratia marcescens is an important pathogen with noteworthy hydrophobicity characteristics as assessed by microbial adhesion to hydrocarbons. However, the present knowledge on the surface characteristics of S. marcescens strains does not include physicochemical properties relevant for adhesion such as surface free energy and zeta potential. Also, little attention has been paid hitherto to the structural features and chemical composition of the cell surface. Therefore, as a primary aim of this paper, we characterized S. marcescens strains by means of contact angle and zeta potential measurements, X-ray photoelectron spectroscopy, and infrared spectroscopy. In addition, transmission electron microscopy on negatively stained (methylamine tungstate) and ruthenium red stained cells was employed to study structural features on the cell surface. Furthermore, as a secondary aim of this paper, the power of the various techniques to discriminate between strains was evaluated. Negative staining showed that S. marcescens RZ almost completely lost its surface fibrils upon increasing the growth temperature from 30 to 37 °C. This loss of surface fibrils was accompanied by a decrease in hydrophobicity, as measured by water contact angles on bacterial lawns. No significant differences in hexadecane contact angles were observed. Zeta potentials were only different for S. marcescens 3164, showing a considerably higher isoelectric point (IEP = 3.9) than the other strains involved (IEP about 2.5). X-ray photoelectron spectroscopy yielded differences in O/C, N/C, and P/C surface concentration ratios, which related with the IEPs of the strains, despite the fact that X-ray photoelectron spectroscopy is done on fully dehydrated cells, whereas zeta potentials are measured on cells in their physiological state. Infrared spectroscopy was not sufficiently surface sensitive to discriminate between these strains. N/C surface concentration ratios by X-ray photoelectron spectroscopy, which probes approximately 5 nm deep from the surface, were slightly higher for the pigmented, prodigiosin-containing strains RZ30 and 3164, although the presence of prodigiosin did not influence the cell surface hydrophobicity. Thus the prodigiosin is probably confined in deeper layers than probed by contact angles (approximately 0.3–0.5 nm). Key words: Serratia marcescens, fibrils, surface properties, hydrophobicity, zeta potential.

Two dimensional Sr silicate grown on Si(001) studied using X-ray Photoelectron Spectroscopy

2006 ◽  
Vol 132 ◽  
pp. 87-90
Author(s):  
M. El Kazzi ◽  
G. Delhaye ◽  
S. Gaillard ◽  
E. Bergignat ◽  
G. Hollinger
Keyword(s):  
Photoelectron Spectroscopy ◽  
Two Dimensional ◽  
X Ray

BONDS IN AMORPHOUS Nb1-xSixSTUDIED BY X-RAY EMISSION AND X-RAY PHOTOELECTRON SPECTROSCOPY

1987 ◽  
Vol 48 (C9) ◽  
pp. C9-1025-C9-1028 ◽  
Author(s):  
W. ZAHOROWSKI ◽  
A. SIMUNEK ◽  
G. WIECH ◽  
K. SÖLDNER ◽  
R. KNAUF ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
X Ray
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