Estimation of Fractional Surface Coverage of Particles for Oxide CMP

2004 ◽  
Vol 151 (5) ◽  
pp. G368 ◽  
Author(s):  
Wonseop Choi ◽  
Seung-Mahn Lee ◽  
Jeremiah Abiade ◽  
Rajiv K. Singh
Keyword(s):  
Surface Coverage ◽  
Fractional Surface Coverage ◽  
Fractional Surface

The influence of fractional surface coverage on the core–core separation in ordered monolayers of thiol-ligated Au nanoparticles

Soft Matter ◽  
2019 ◽  
Vol 15 (43) ◽  
pp. 8800-8807 ◽  
Author(s):  
Morgan Reik ◽  
Melanie Calabro ◽  
Sean Griesemer ◽  
Edward Barry ◽  
Wei Bu ◽  
...  
Keyword(s):  
Long Range ◽  
Au Nanoparticles ◽  
Surface Coverage ◽  
Langmuir Monolayers ◽  
Long Range Order ◽  
The Core ◽  
Nanoparticle Surface ◽  
Nanoparticle Interactions ◽  
Fractional Surface Coverage ◽  
Fractional Surface

This study examines the way in which fractional surface coverage on a nanoparticle surface affects nanoparticle interactions and the long-range order of Langmuir monolayers.

A theoretical analysis and computer simulation of the growth of epitaxial films

1971 ◽  
Vol 321 (1544) ◽  
pp. 53-68 ◽  
Keyword(s):  
Computer Simulation ◽  
Random Distribution ◽  
Surface Coverage ◽  
Epitaxial Films ◽  
Interface Area ◽  
Crystalline Substrate ◽  
The Mean ◽  
Fractional Surface Coverage ◽  
Fractional Surface ◽  
Island Density

Equations are derived which describe the growth of epitaxial islands on a crystalline substrate subject to certain restrictions, and an attempt is made to define the limits of their application in a physical system. For an initial random distribution of point nuclei, the growth of islands which instantaneously coalesce to a fixed shape obeys equations of the form : In ( N / N 0 ) = -2 N ⅓ 0 A V -⅔ T ⅔ for N 0 > N > 10 -2 N 0 and P = P 0 (1- N / N 0 ) for all N , where 0.5 < P 0 < 0.6. In these equations the island distribution is described in terms of three parameters: the island density N , the fractional surface coverage P and the mean thickness T . The constants A and V are fixed by the shape of an island of size r , such that the volume is Vr 3 and the interface area is Ar 2 .

The microstructure of functionalized poLyacrylonitrile beads for bioseparations

1990 ◽  
Vol 48 (4) ◽  
pp. 1094-1095
Author(s):  
Eduardo A. Kamenetzky ◽  
David A. Ley
Keyword(s):  
Aqueous Solution ◽  
Affinity Chromatography ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Surface Coverage ◽  
Vacuum Impregnation ◽  
Thin Sections ◽  
Selective Staining ◽  
Low Viscosity ◽  
Diamond Knife

The microstructure of polyacrylonitrile (PAN) beads for affinity chromatography bioseparations was studied by TEM of stained ultramicrotomed thin-sections. Microstructural aspects such as overall pore size distribution, the distribution of pores within the beads, and surface coverage of functionalized beads affect performance properties. Stereological methods are used to quantify the internal structure of these chromatographic supports. Details of the process for making the PAN beads are given elsewhere. TEM specimens were obtained by vacuum impregnation with a low-viscosity epoxy and sectioning with a diamond knife. The beads can be observed unstained. However, different surface functionalities can be made evident by selective staining. Amide surface coverage was studied by staining in vapor of a 0.5.% RuO4 aqueous solution for 1 h. RuO4 does not stain PAN but stains, amongst many others, polymers containing an amide moiety.

Further Evidence that Glycoprotein IIb-IIIa Mediates Platelet Spreading on Subendothelium

1991 ◽  
Vol 65 (02) ◽  
pp. 202-205 ◽  
Author(s):  
Harvey J Weiss ◽  
Vincet T Turitto ◽  
Hans R Baumgartner
Keyword(s):  
Platelet Adhesion ◽  
Surface Coverage ◽  
Rabbit Aorta ◽  
Conclusive Evidence ◽  
Initial Contact ◽  
Single Exposure ◽  
Vessel Segment ◽  
Multiple Exposures ◽  
Wall Interaction ◽  
Platelet Spreading

SummaryIn order to explore further the mechanism by which glycoprotein GPIIb-IIIa promotes platelet vessel wall interaction, platelet adhesion to subendothelium was studied in an annular chamber in which subendothelium from rabbit aorta was exposed at a shear rate of 2,600 s−1 to blood from patients with thrombasthenia. Perfusions were conducted for each of 5 exposure times (1 ,2,3, 5 and 10 min), and the percent surface coverage of the vessel segment with platelets in the contact (C) and spread (S) stage was determined. Increased values of platelet contact (C) were obtained in thrombasthenia at all exposure times; this finding is consistent with a defect in platelet spreadirg, based on a previously described kinetic model of platelet attachment to subendothelium. According to this model of attachment, increased values of platelet contact (C) at a single exposure time may be indicative of either a defect in spreading (S) or initial contact (C), but multiple exposures will result in increased contact only for defects which are related to defectiye platelet spreading (s).The results obtained over a broad range of exposure times provide more conclusive evidence that GPIIb-IIIa mediates platelet spreading than those previously obtained at single exposure times.

Automated Microdensitometry And Protein Assays As Measures For Platelet Adhesion And Aggregation On Collagen Coated Slides Under Controlled Flow Conditions

1979 ◽  
Author(s):  
R Muggli ◽  
H Baumgartner ◽  
Th Tschopp
Keyword(s):  
Surface Coverage ◽  
Platelet Surface ◽  
En Face ◽  
Uncoated Surface ◽  
Unit Surface ◽  
Perfusion Time ◽  
Flowing Blood ◽  
Controlled Flow ◽  
Protein Assays ◽  
Microscope Slides

Microscope slides were homogeneously coated over a length of 2 cm with a mixture of soluble and fibrillar collagen and exposed at 37°C and under laminar flow to citrated whole rabbit blood at a flow-rate of 100 ml/min. Surface coverage with platelets (adhesion) and platelet accumulations higher than about 5 μm in height (aggregation) were determined by automated microdensitometry of fuchsine stained ‘en face’ preparations. The platelet mass per unit surface was measured with a modified Lowry technique whose sensitivity was equivalent to 5×l05platelets. Platelet number, amount of protein and surface coverage with platelet accumulations correlated. After a perfusion time of 10 min thrombi up to 30 μm in height and oriented in the direction of flow had developed on the collagen coated area. Surface coverage with platelets was 75% and the amount of deposited protein 1.4 μg/mm2(2×l06platelets/mm2). On the uncoated surface single platelets predominated; the surface coverage was 20% and the density of platelets 8×104/mm2. Acetyl- salicylic acid at 100 μm decreased platelet aggregation by about 80% without affecting adhesion.The new parallel plate perfusion system offers rapid quantitation of platelet-surface and platelet-platelet interaction after exposure to flowing blood and iftay also be diagnostically useful.

The Nature of Chemisorbed CO2 in Zeolite A

2019 ◽  
Author(s):  
Przemyslaw Rzepka ◽  
Zoltán Bacsik ◽  
Andrew J. Pell ◽  
Niklas Hedin ◽  
Aleksander Jaworski
Keyword(s):  
Solid State ◽  
Ir Spectroscopy ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Surface Coverage ◽  
Gas Mixtures ◽  
Mas Nmr ◽  
Significant Fraction ◽  
Zeolite A

Formation of CO<sub>3</sub><sup>2-</sup> and HCO<sub>3</sub><sup>-</sup> species without participation of the framework oxygen atoms upon chemisorption of CO<sub>2</sub> in zeolite |Na<sub>12</sub>|-A is revealed. The transfer of O and H atoms is very likely to have proceeded via the involvement of residual H<sub>2</sub>O or acid groups. A combined study by solid-state <sup>13</sup>C MAS NMR, quantum chemical calculations, and <i>in situ</i> IR spectroscopy showed that the chemisorption mainly occurred by the formation of HCO<sub>3</sub><sup>-</sup>. However, at a low surface coverage of physisorbed and acidic CO<sub>2</sub>, a significant fraction of the HCO<sub>3</sub><sup>-</sup> was deprotonated and transformed into CO<sub>3</sub><sup>2-</sup>. We expect that similar chemisorption of CO<sub>2</sub> would occur for low-silica zeolites and other basic silicates of interest for the capture of CO<sub>2</sub> from gas mixtures.

Work function studies of propylene, acetylene, hydrogen and nitrogen chemisorption on molybdenum

1982 ◽  
Vol 47 (11) ◽  
pp. 2996-3003
Author(s):  
Zdeněk Bastl
Keyword(s):  
Work Function ◽  
Surface Topography ◽  
Surface Coverage ◽  
Dissociative Chemisorption ◽  
Complete Coverage ◽  
Surface Sites ◽  
Function Change ◽  
Work Function Change

The work function changes of vacuum deposited molybdenum films caused by the chemisorption of propylene, acetylene, hydrogen and nitrogen were measured using the Kelvin vibrating capacitor method. During the hydrocarbon chemisorption, the work function increased in a low surface coverage region but decreased at the higher surface coverages. The saturation values of the work function changes corresponding to complete coverage of the surface by chemisorbed propylene and acetylene equal -0.08 eV and -0.42 eV, respectively. The observed dependences of the work function change on surface coverage are interpreted by the dissociative chemisorption of hydrocarbons on a limited number of surface sites which are simultaneously the sites of preferred adsorption. The extent of dissociation decreases in the adsorption with the increasing surface coverage. The results of the study of the work function changes induced by the hydrogen and nitrogen chemisorption enabled to draw several conclusions on the surface topography of the used films.

A Comparative Study of Adsorption of Aliphatic Amines at a Gold Electrode

2005 ◽  
Vol 70 (12) ◽  
pp. 2027-2037 ◽  
Author(s):  
Teresa Łuczak
Keyword(s):  
Gibbs Energy ◽  
Comparative Study ◽  
Gold Electrode ◽  
Surface Coverage ◽  
Standard Gibbs Energy ◽  
Gold Surface ◽  
Experimental Dependence ◽  
Aliphatic Amines ◽  
Solvent Interactions ◽  
Amine Concentration

Adsorption of aliphatic amines (C1-C4) at the gold electrode was studied by tensammetry. It has been established that the experimental dependence between the gold surface coverage (Θ) and the bulk amine concentration (cA) fits satisfactorily both by the Frumkin and Flory-Huggins isotherms. The standard Gibbs energy of adsorption, ∆G°ad at Emax for Θ < 0.8 has been found to increase in the order methylamine < ethylamine < propylamine < butylamine. This is rationalised in terms of surface-adsorbate, adsorbate-adsorbate and adsorbate-solvent interactions.

scholarly journals Initial Clinical Experience With a New Conformable Abdominal Aortic Endograft: Aortic Neck Coverage and Curvature Analysis in Challenging Aortic Necks

2021 ◽  
pp. 152660282199672
Author(s):  
Alice Finotello ◽  
Richte Schuurmann ◽  
Sara Di Gregorio ◽  
Gian Antonio Boschetti ◽  
Nabil Chakfé ◽  
...  
Keyword(s):  
Aortic Wall ◽  
Surface Coverage ◽  
Infrarenal Aorta ◽  
Technical Success ◽  
Curvature Analysis ◽  
Average Curvature ◽  
Aortic Neck ◽  
Abdominal Aortic ◽  
Shortest Distance ◽  
New Generation

Objectives: Aim of this work was to investigate precision of deployment and conformability of a new generation GORE EXCLUDER Conformable Endoprosthesis with active control system (CEXC Device, W.L. Gore and Associates, Flagstaff, AZ, USA) by analyzing aortic neck coverage and curvature. Methods: All consecutive elective patients affected by abdominal aortic aneurysm or aortoiliac aneurysm treated at our institution between November 2018 and June 2019 with the new CEXC Device were enrolled. Validated software was adopted to determine the available apposition surface area into the aortic neck, apposition of the endograft to the aortic wall, shortest apposition length (SAL), shortest distance between the endograft fabric and the lowest renal arteries (SFD) and between the endograft fabric and the contralateral renal artery (CFD). Pointwise centerline curvature was also computed. Results: Twelve patients (10 men, median age 78 years (71.75, 81.0)) with available pre- and postoperative computed tomography angiography (CTA) were included. Technical success was obtained in all the cases. Preoperative median length of the proximal aortic neck was 16.1 mm (10.7, 21.7) and suprarenal (α) and infrarenal (β) neck angulation were, respectively, 28.9° (15.7°, 47.5°) and 75.0° (66.9°, 81.4°). Postoperative median apposition surface coverage was 79% (69.25%, 90.75%) of the available apposition surface. SFD and CFD were 1.5 mm (0.75, 5.25) and 7 mm (4.5, 21.5), respectively. Average curvature over the infrarenal aorta decreased from 25 m−1 (21.75, 29.0) to 22.5 m−1 (18.75, 24.5) postoperatively (p=0.02). Maximum curvature did not decrease significantly from 64.5 m−1 (54.25, 92.0) to 62 m−1 (41.75, 71.5) (p=0.1). Conclusions: Our early experience showed that deployment of the CEXC Device is safe and effective for patients with challenging proximal aortic necks. Absence of significant changes between pre- and postoperative proximal aortic neck angulations and curvature confirms the high conformability of this endograft.

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