scholarly journals Morphology of PbTe Crystal Surface Sputtered by Argon Plasma under Secondary Neutral Mass Spectrometry Conditions

2016 ◽  
Vol 17 (3) ◽  
pp. 336-341 ◽  
Author(s):  
D.M. Zayachuk ◽  
A. Csik ◽  
V.E. Slynko
Keyword(s):  
Mass Spectrometry ◽  
Crystal Surface ◽  
Depth Profiling ◽  
Argon Plasma ◽  
Surface Structures ◽  
The Other ◽  
Ion Energy ◽  
The One ◽  
Average Size ◽  
Microscopic Surface

We have investigated morphology of the lateral surfaces of PbTe crystal samples grown from melt by the Bridgman method sputtered by Ar+ plasma with ion energy of 50 – 550 eV for 5 - 50 minutes under Secondary Neutral Mass Spectrometry (SNMS) conditions. The sputtered PbTe crystal surface was found to be simultaneously both the source of sputtered material and the efficient substrate for re-deposition of the sputtered material during the depth profiling. During sputtering PbTe crystal surface is forming the dimple relief. To be re-deposited the sputtered Pb and Te form arrays of the microscopic surface structures in the shapes of hillocks, pyramids, cones and others on the PbTe crystal sputtered surface. Correlation between the density of re-deposited microscopic surface structures, their shape, and average size, on the one hand, and the energy and duration of sputtering, on the other, is revealed.

scholarly journals Formation of the Sputtered Phase of PbTe Crystals by Ar+ Plasma and Re-deposition of the Sputtered Species at Secondary Neutral Mass Spectrometry Conditions

2017 ◽  
Vol 18 (1) ◽  
pp. 21-28 ◽  
Author(s):  
D.M. Zayachuk ◽  
V.E. Slynko ◽  
A. Csik
Keyword(s):  
Mass Spectrometry ◽  
Mutual Influence ◽  
Crystal Surface ◽  
Depth Profiling ◽  
Surface Structures ◽  
Average Intensity ◽  
Ar Plasma ◽  
Deposition Processes ◽  
Critical Nuclei

Formation of the Pb and Te sputtered phase under exposure of the lateral surface of PbTe crystals grown from melt by the Bridgman method by Ar+ plasma at Secondary Neutral Mass Spectrometry (SNMS) conditions and re-deposition of the sputtered species on the sputtering crystal surface are investigated. Experimental evidence of mutual influence of the sputtering and re-deposition processes on each other during prolonged depth profiling of PbTe crystals is presented. Sputtering of the PbTe crystal surface forms the strongly supersaturated sputtered phase of Pb and Te. Re-deposition of the Pb and Te sputtered atoms on the crystal surface results in oscillations of sputtering rate of PbTe crystal and changes of average intensity of Pb and Te sputtering over sputtering time. A possible role of both the sub-critical nuclei of newly re-deposited phase and the re-deposited surface structures of post-critical sizes in generation of the features of PbTe crystal sputtering is discussed. It is concluded that formation and re-sputtering of the sub-critical nuclei of re-deposited phase leads to the oscillations of sputter yields of Pb and Te. Growth and re-sputtering of the re-deposited surface structures of post-critical sizes lead to changes of average values of Pb and Te sputter yields.

Assortment Size and PL Penetration in Grocery Retailers' Portfolios during Economic Crisis

2016 ◽  
pp. 244-274 ◽  
Author(s):  
José Luis Ruiz-Real ◽  
Juan Carlos Gázquez-Abad ◽  
Francisco J. Martínez-López
Keyword(s):  
Economic Crisis ◽  
The Other ◽  
Product Categories ◽  
Other Hand ◽  
Competitive Prices ◽  
The One ◽  
Average Size ◽  
Buying Behaviour ◽  
Retail Formats

The economic crisis in Spain has had a major impact on the evolution of retail assortments in food base. On the one hand, it has caused alterations in assorted sizes, as well as in the distribution between NB and PL. On the other hand, it has changed the buying behaviour of consumers seeking brands that offer confidence, but at very competitive prices. The purpose of this chapter is to answer the following questions: How has the economic crisis changed the assortment size in different categories of products in Spanish groceries? In which way has the assortment composition of retailers been altered? Do all the retail formats have the same behaviour in assortment management and PL? The authors argue that there has been an increase in the average size of assortment for all the product categories with the exception of products of fill-ins, and the only two retail formats that have increased the weight of the PL in their assortments are large and medium-sized supermarkets.

The Influence of Recombination between Holes and Reduced Redox Ions on the Efficiency of Hole Injection from Electrolytic Contacts into Organic Insulator Crystals

1976 ◽  
Vol 31 (8) ◽  
pp. 981-986 ◽  
Author(s):  
F. Willig ◽  
G. Scherer
Keyword(s):  
Field Strength ◽  
External Field ◽  
Crystal Surface ◽  
Extreme Case ◽  
The Other ◽  
Hole Injection ◽  
The One ◽  
Suitable System ◽  
Hole Generation ◽  
Crystal Bulk

Abstract The efficiency of hole injection from electrolytic contacts into organic insulator crystals is con-trolled by hole generation and hole destruction at the crystal surface through oxidized and reduced redox ions respectively and by hole escape into the crystal bulk which competes with hole destruction. By increasing the concentration of reduced redox ions from virtually zero in a suitable system the transition has been studied from the one extreme case where all the generated holes contribute to the injection current to the other extreme case where the majority of the generated holes recombines with reduced redox ions before they can escape into the crystal bulk. From the experiments one can deduce that the generated hole spends less than 10-10 s within the reaction distance of its reduced parent redox ion, at external field strengths ≧ 104 V/cm, but returns to the crystal surface during a much longer time, e.g. during about 10-8 s at an external field strength of 105 V/cm, before it can escape finally into the crystal bulk.

Behavior of Cr-Rich Phase during Rapid Solidification Cu71Cr29 Alloys

2011 ◽  
Vol 228-229 ◽  
pp. 101-105
Author(s):  
Zhi Ming Zhou ◽  
Li Wen Tang ◽  
Jing Luo ◽  
Tao Zhou ◽  
Jie Zhan ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Rapid Solidification ◽  
Melt Spinning ◽  
The Other ◽  
Solidification Behavior ◽  
Rich Phase ◽  
Splat Quenching ◽  
The One ◽  
Average Size ◽  
Scanning Electron

Behavior of Cr-rich phase in rapid solidification Cu71Cr29 alloys was investigated by using melt spinning and splat quenching. The microstructure and solidification behavior of the Cr-rich were investigated by scanning electron microscopy (SEM). The results showed that the alloys generally have a microstructure consisting of a fine dispersion of a Cr-rich phase in a Cu-rich matrix. However, the morphology and size of the Cr-rich phase vary greatly with the cooling rate. On the one hand, the average size of the Cr-rich phase is reduced with increasing cooling rate. On the other hand, the Cr-rich phase show both dendrites and spheroids for lower cooling rate but only spheroids for the higher cooling rate. This means liquid phase separation occurred during rapid solidification. The results were discussed with respect to the formation of the Cr-rich spheroids during rapid solidification.

scholarly journals Productivity in Small Business: An Analysis Using African Data

1986 ◽  
Vol 11 (1) ◽  
pp. 27-42 ◽  
Author(s):  
A. Roy Thurik
Keyword(s):  
Small Business ◽  
South African ◽  
Support System ◽  
The Other ◽  
Cost Functions ◽  
Average Volume ◽  
Service Business ◽  
Business Support ◽  
The One ◽  
Average Size

Labor and floorspace cost functions are derived for small business trade. Relationships are proposed between average volume of labor or average floorspace per establishment on the one hand, and average size per establishment, average rental paid, percentage selling space, and indicators of business type and location on the other. Promising estimation results are reported using South African data of 1979/1980. The method however Is not restricted to the South African case. A productivity business support system can be developed providing productivity standards for any area in the small (service) business. An analysis similar to the one presented here, but relating to the area in question, should precede the development of such a system.

Feeding relationships between sympatric Afrotropical tree frogs (genus Hyperolius): The effects of predator body size and season

2004 ◽  
Vol 54 (3) ◽  
pp. 293-302 ◽  
Author(s):  
◽  
◽  
◽  
◽  
◽  
...  
Keyword(s):  
Interspecific Competition ◽  
Diet Composition ◽  
Sexual Size Dimorphism ◽  
Stomach Contents ◽  
The Other ◽  
Size Dimorphism ◽  
Frog Species ◽  
Tree Frogs ◽  
The One ◽  
Average Size

AbstractThe feeding relationships of four sympatric, ecologically nearly unknown, tree frogs of southern Nigeria (Hyperolius sylvaticus, H. guttulatus, H. fusciventris burtoni, and H. concolor) were studied during both the dry and the rainy seasons. Stomach contents were obtained by stomach flushing. The largest species were H. guttulatus and H. concolor, whereas the other two species were of smaller average size. A statistically significant sexual size dimorphism was observed in H. guttulatus, H. concolor, and H. sylvaticus (in all species the females were larger), but not in H. fusciventris. In all four species, the frequency of animals with empty stomachs was significantly lower during the rainy season than during the dry season. The four frog species were mainly arthropodeating: Araneidae and Blattoidea were preyed upon mainly by the two largest species, Acarina and Lepidoptera were taken mainly by the two smaller species, and Diptera and Formicoidea were eaten frequently by all species. The diet composition was similar between seasons in three of the four species, and H. guttulatus was the only species showing considerable diet variation between seasons. We concluded that 1) the intensity of interspecific competition should be particularly high between the two larger species on the one hand, and between the two smaller species on the other hand; and 2) the intensity of the interspecific competition should be relatively constant throughout the year.

scholarly journals Investigation on the Anaphylaxis and Anti-Digestive Stable Peptides Identification of Ultrasound-Treated α-Lactalbumin during In-Vitro Gastroduodenal Digestion

Foods ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2760
Author(s):  
Xumei Wang ◽  
Zongcai Tu ◽  
Guangxian Liu ◽  
Hui Wang ◽  
Yueming Hu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Tertiary Structure ◽  
High Resolution Mass Spectrometry ◽  
Conformational Epitope ◽  
The Other ◽  
Linear Epitopes ◽  
The One ◽  
Resolution Mass

Our previous studies indicated that ultrasound treatment can increase the anaphylaxis of protein. However, investigation on the anaphylaxis changes of ultrasound-treated α-lactalbumin (ALA) during digestion is lacking. The anaphylaxis of ultrasound-treated ALA and its digesta was investigated. The anti-digestive stable peptides were identified by high-resolution mass spectrometry. Ultrasound induced the tertiary structure of ALA to unfold and increased its anaphylaxis. During digestion, the anaphylaxis of both gastric and gastroduodenal digesta was further increased. There are two reasons for this phenomenon. On the one hand, linear epitopes played an important role in affecting anaphylaxis compared with the conformational epitope, and some linear epitopes were still retained on the anti-digestive stable peptides produced after gastroduodenal digestion, resulting in increased anaphylaxis after digestion. On the other hand, the presence of intact ALA molecules after digestion still remained strong anaphylaxis. Compared with the digesta of untreated ALA, the digesta of ultrasound-treated ALA possessed higher anaphylaxis. The results indicated that ultrasound increased the anaphylaxis of ALA during digestion.

scholarly journals Variation of Surface Nanostructures on (100) PbS Single Crystals during Argon Plasma Treatment

Crystals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 111
Author(s):  
Sergey P. Zimin ◽  
Nikolai N. Kolesnikov ◽  
Ildar I. Amirov ◽  
Viktor V. Naumov ◽  
Egor S. Gorlachev ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Single Crystals ◽  
Crystal Surface ◽  
Minimum Energy ◽  
Argon Plasma ◽  
Zone Melting ◽  
Liquid Lead ◽  
Ion Energy ◽  
Treatment Conditions ◽  
Surface Nanostructures

The nanostructuring of the (100) PbS single crystal surface was studied under varying argon plasma treatment conditions. The initial PbS single crystals were grown by high-pressure vertical zone melting, cut into wafer samples, and polished. Subsequently, the PbS single crystals were treated with inductively coupled argon plasma under varying treatment parameters such as ion energy and sputtering time. Plasma treatment with ions at a minimum energy of 25 eV resulted in the formation of nanotips with heights of 30–50 nm. When the ion energy was increased to 75–200 eV, two types of structures formed on the surface: high submicron cones and arrays of nanostructures with various shapes. In particular, the 120 s plasma treatment formed specific cruciform nanostructures with lateral orthogonal elements oriented in four <100> directions. In contrast, plasma treatment with an ion energy of 75 eV for 180 s led to the formation of submicron quasi-spherical lead structures with diameters of 250–600 nm. The nanostructuring mechanisms included a surface micromasking mechanism with lead formation and the vapor–liquid–solid mechanism, with liquid lead droplets acting as self-forming micromasks and growth catalysts depending on the plasma treatment conditions (sputtering time and rate).

Note on Selection of Coordinate Systems for Geodynamics

1975 ◽  
Vol 26 ◽  
pp. 395-407
Author(s):  
S. Henriksen
Keyword(s):  
Sea Level ◽  
The Other ◽  
Coordinate Systems ◽  
Mean Sea Level ◽  
The Earth ◽  
The One ◽  
Static Systems ◽  
Selection Of

The first question to be answered, in seeking coordinate systems for geodynamics, is: what is geodynamics? The answer is, of course, that geodynamics is that part of geophysics which is concerned with movements of the Earth, as opposed to geostatics which is the physics of the stationary Earth. But as far as we know, there is no stationary Earth – epur sic monere. So geodynamics is actually coextensive with geophysics, and coordinate systems suitable for the one should be suitable for the other. At the present time, there are not many coordinate systems, if any, that can be identified with a static Earth. Certainly the only coordinate of aeronomic (atmospheric) interest is the height, and this is usually either as geodynamic height or as pressure. In oceanology, the most important coordinate is depth, and this, like heights in the atmosphere, is expressed as metric depth from mean sea level, as geodynamic depth, or as pressure. Only for the earth do we find “static” systems in use, ana even here there is real question as to whether the systems are dynamic or static. So it would seem that our answer to the question, of what kind, of coordinate systems are we seeking, must be that we are looking for the same systems as are used in geophysics, and these systems are dynamic in nature already – that is, their definition involvestime.

Ultrathin Platinum Crystal Surface Structures

1985 ◽  
Vol 43 ◽  
pp. 394-395
Author(s):  
R. L. Hines
Keyword(s):  
Crystal Surface ◽  
Surface Structures ◽  
Platinum Surface ◽  
Platinum Surfaces ◽  
Resolution Level ◽  
Experimental Facilities ◽  
Carbon Backing ◽  
Mesh Grid ◽  
Atom Layer

The importance of atom layer terraces or steps on platinum surfaces used for catalysis as discussed by Somorjai justifies an extensive investigation of the structure of platinum surfaces through electron microscopy at the atomic resolution level. Experimental and theoretical difficulties complicate the quantitative determination of platinum surface structures but qualitative observation of surface structures on platinum crystals is now possible with good experimental facilities.Ultrathin platinum crystals with nominal 111 orientation are prepared using the procedure reported by Hines without the application of a carbon backing layer. Platinum films with thicknesses of about ten atom layers are strong enough so that they can be mounted on grids to provide ultrathin platinum crystals for examination of surface structure. Crystals as thin as possible are desired to minimize the theoretical difficulties in analyzing image contrast to determine structure. With the current preparation procedures the crystals frequently cover complete openings on a 400 mesh grid.

Sign in / Sign up

Export Citation Format

Share Document