The Initial Growth Stages and Crystallization Mechanism of Bi-based films

2002 ◽  
Vol 721 ◽  
Author(s):  
Oleg V. Kononenko ◽  
Alexandra V. Andreeva ◽  
Alexandr I. Il'in
Keyword(s):  
Grain Orientation ◽  
Evaporation Rate ◽  
Thermal Evaporation ◽  
Growth Stages ◽  
Initial Growth ◽  
Growth Mechanisms ◽  
Coalescence Process ◽  
Stages Of Growth ◽  
Island Evolution ◽  
Substrate Temperatures

AbstractThe present work deals with investigation of the initial stages of growth of (Bi, Bi-Sb) films deposited by the methods of different degrees of nonequilibrium, such as thermal evaporation (TE) and self-ion assisted deposition (SIAD). The comparative analysis of growth mechanisms and film island evolution (faceting and coalescence) was carried out depending on the type (crystalline, amorphous) and temperature of substrate, evaporation rate, film composition, etc. Ion bombardment during deposition leads to films of higher density and reduced porosity, and greater stability than those deposited without bombardment. As compared with the pure Bi films the facetted island morphology of the SIAD Bi–Sb (20%) films is not so clear. This is explained by partial realization of the coalescence process by the liquid fluidity mechanism. At all substrate temperatures the grain orientation (111) R is more pronounced for SIAD films than for the TE films.

Nucleation, first growth stages and structure of nano-sized polymer coatings deposited from active gas phase

2021 ◽  
Author(s):  
A.A. Rogachev
Keyword(s):  
Structure Formation ◽  
Gas Phase ◽  
Composite Coatings ◽  
Substrate Surface ◽  
Polymer Coatings ◽  
Single Component ◽  
Silver Nanoclusters ◽  
Growth Stages ◽  
Initial Growth ◽  
Stages Of Growth

This paper presents an analysis of the structural-morphological, kinetic patterns of the initial growth stages of single-component and composite (polymer-polymer and metal-polymer) nanoscale coatings based on the products of electron-beam dispersion of polymers. The main features of the deposition processes from the active gas phase occurring on the substrate surface and the established size dependences of the structure and molecular composition are explained on the basis of the adsorption-polymerization mechanism for the formation of coatings. It was established that among the most important features of the deposition process from the active gas phase is the simultaneous flow of polymerization and structure formation of adsorbed molecular fragments of the polymer under the conditions of exposure of the active components of the plasma, dispersive filler, and the substrate surface. This feature has a decisive influence on the nucleation of polymer particles, the molecular structure and morphology of nanoscale layers, as well as the dependence of their properties on thickness. Using the PTFE and PE coatings, it was shown that the orientation and ordering of the formed layers changes during the coating growth: at the initial stages of deposition in the layer up to 150 nm, the molecules are oriented predominantly parallel, and in thicker layers due to the bulk structure formation perpendicularly substrate surface. When deposited on the surface subjected to plasma treatment, the growth rate of the formed coating at the initial stages of growth increases by more than 5 times. At the same time, such layers contain predominantly linear molecules with a relatively lower molecular weight. The introduction of micro-and nanoscale polymer coatings in the process of their growth of the formed silver or copper nanoclusters leads to the formation of highly oriented, continuous, highly dispersed layers already at the initial stages of growth. The orientation of the macromolecules of the matrix with the maintenance of Ag or Cu nanoclusters in it has parameters characteristic of single-component coatings. In PTFE+Mo coatings, a linear dependence of molecular orientation on the layer thickness appears. In composite coatings containing silver nanoclusters, the effect of selective plasmon absorption was established.

scholarly journals Effects of Non-Thermal Plasma Treatment on Seed Germination and Early Growth of Leguminous Plants—A Review

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1616
Author(s):  
Božena Šerá ◽  
Vladimír Scholtz ◽  
Jana Jirešová ◽  
Josef Khun ◽  
Jaroslav Julák ◽  
...  
Keyword(s):  
Seed Germination ◽  
Plant Species ◽  
Thermal Plasma ◽  
Microbial Inactivation ◽  
Growth Stages ◽  
Agricultural Crop ◽  
Initial Growth ◽  
Total Production ◽  
Legume Seeds ◽  
Non Thermal Plasma

The legumes (Fabaceae family) are the second most important agricultural crop, both in terms of harvested area and total production. They are an important source of vegetable proteins and oils for human consumption. Non-thermal plasma (NTP) treatment is a new and effective method in surface microbial inactivation and seed stimulation useable in the agricultural and food industries. This review summarizes current information about characteristics of legume seeds and adult plants after NTP treatment in relation to the seed germination and seedling initial growth, surface microbial decontamination, seed wettability and metabolic activity in different plant growth stages. The information about 19 plant species in relation to the NTP treatment is summarized. Some important plant species as soybean (Glycine max), bean (Phaseolus vulgaris), mung bean (Vigna radiata), black gram (V. mungo), pea (Pisum sativum), lentil (Lens culinaris), peanut (Arachis hypogaea), alfalfa (Medicago sativa), and chickpea (Cicer aruetinum) are discussed. Likevise, some less common plant species i.g. blue lupine (Lupinus angustifolius), Egyptian clover (Trifolium alexandrinum), fenugreek (Trigonella foenum-graecum), and mimosa (Mimosa pudica, M. caesalpiniafolia) are mentioned too. Possible promising trends in the use of plasma as a seed pre-packaging technique, a reduction in phytotoxic diseases transmitted by seeds and the effect on reducing dormancy of hard seeds are also pointed out.

Echinoderm skeletal crystallography and paleobiological applications

1997 ◽  
Vol 3 ◽  
pp. 191-204 ◽  
Author(s):  
B. E. Bodenbender
Keyword(s):  
Skeletal Structure ◽  
Growth Stages ◽  
Full Potential ◽  
Initial Growth ◽  
Developmental Sequence ◽  
Coarse Scale ◽  
Common Pattern ◽  
Plate Morphology ◽  
Oriented Parallel ◽  
High Level

The crystallographic orientations of echinoderm skeletal elements can supplement standard morphological comparisons in the exploration of echinoderm evolution. At a coarse scale, many echinoderms share a crystallographic pattern in whichcaxes radiate away from the axis of pentaradial symmetry. Within this common pattern, however,caxes of different taxa can differ dramatically in their degree of variability, angles of inclination, and relationships to the external morphology of skeletal elements. Crystallographic data reflect a variety of taxon-specific influences and therefore reveal different information in different taxa. In echinoids, orientations ofcaxes in coronal plates correlate well with high-level taxonomic groupings, whilecaxes of apical plates record modes of larval development. In blastoids,caxes of radial plates have a structural interpretation, with thecaxis oriented parallel to the orientation of the surface of the radial plate during its initial growth stages. In crinoids,caxes do not correlate with taxonomic group, plate morphology, or developmental sequence, but instead correlate with relative positions of skeletal elements on the calyx. Although their full potential has yet to be explored, the varied crystallographic patterns in echinoderms have been used to clarify skeletal structure, characterize developmental anomalies, and infer homologies of skeletal plates both within specimens and between groups. A axes are less constrained in their orientations thancaxes and offer less promise of revealing novel paleobiological information.

Allocation of proteolytic activity in the seedling of Cynara cardunculus L. in the initial growth stages

2008 ◽  
Vol 165 (10) ◽  
pp. 1041-1048 ◽  
Author(s):  
Mafalda Sales-Gomes ◽  
Ana Margarida Cavaco ◽  
Maria Emilia Lima-Costa
Keyword(s):  
Proteolytic Activity ◽  
Growth Stages ◽  
Initial Growth ◽  
Cynara Cardunculus

Effects of morphology of buffer layers on ZnO/sapphire heteroepitaxial growth by RF magnetron sputtering

2015 ◽  
Vol 1741 ◽  
Author(s):  
Tomoaki Ide ◽  
Koichi Matsushima ◽  
Ryota Shimizu ◽  
Daisuke Yamashita ◽  
Hynwoong Seo ◽  
...  
Keyword(s):  
Rf Magnetron Sputtering ◽  
Buffer Layers ◽  
Crystal Nucleation ◽  
Zno Films ◽  
Growth Stages ◽  
Initial Growth ◽  
Height Distribution ◽  
Heteroepitaxial Growth ◽  
Distribution Profile

ABSTRACTEffects of surface morphology of buffer layers on ZnO/sapphire heteroepitaxial growth have been investigated by means of “nitrogen mediated crystallization (NMC) method”, where the crystal nucleation and growth are controlled by absorbed nitrogen atoms. We found a strong correlation between the height distribution profile of NMC-ZnO buffer layers and the crystal quality of ZnO films. On the buffer layer with a sharp peak in height distribution, a single-crystalline ZnO film with atomically-flat surface was grown. Our results indicate that homogeneous and high-density nucleation at the initial growth stages is critical in heteroepitaxy of ZnO on lattice mismatched substrates.

scholarly journals Effect of fungicides on the enzymatic activity of the antioxidant system and the chlorophyll content in lupine plants during seed dressing

2020 ◽  
pp. 3-6
Author(s):  
O. Borzykh ◽  
O. Tsurkan ◽  
L. Chervyakova ◽  
T. Panchenko
Keyword(s):  
Analytical Chemistry ◽  
Chlorophyll Content ◽  
Peroxidase Activity ◽  
Catalase Activity ◽  
Control Level ◽  
Growth Stages ◽  
Enzymatic System ◽  
Initial Growth ◽  
Seed Dressing ◽  
Catalase Peroxidase

Goal. The effect of fungicides on the dynamics of the activity of peroxidase, catalase (CAT) and chlorophyll content in lupine plants during seed dressing has been established. Methods. Laboratory and vegetation researches were conducted in the laboratory of analytical chemistry of pesticides of the Institute of Plant Protection. Yellow lupine (Lupinus luteus L.), variety Obriy has been grown. The objects of research were fungicides triticonazol (40 g/t) and its combination with prochloraz (120 g/t). Determination of the content of fungicides in plants was carried out using chromatographic methods according to officially approved methods and me­thods developed in the laboratory of analytical chemistry of pesticides. Chlorophyll content and peroxidase activity were measured by colorimetric method, catalase activity — by titrimetric method. Results. According to the research results, the varying sensitivity of the enzymatic system of antioxidant defense (catalase, peroxidase) in response to seed dressing by fungicides was recorded. It showed that on the 10th day after sowing, content of triticonazol in plants was 0.8 mg/kg, and the peroxidase activity was similar to that in untreated plants. Subsequently, against the background of a decrease in the content of the active substance, a gradual activation of the enzyme was observed. Catalase activity also gradually increased beginning from the 14th day, and on the 30th day it exceeded the corresponding control indicator by 40%. When using a combination of triticonazol with prochloraz, the disturbance in the balance of peroxidase catalase was more significant. However, by the phase of 7—8 leaves, with a minimal total content of fungicides (0.38 mg/kg), the enzyme activity approached the control level, which is associated with the restoration of plant homeostasis and the formation of its adaptive potential under stress conditions. The stimulating effect of these fungicides on chlorophyll content at the initial growth stages of lupine was established. The chlorophyll concentration in fungicides-treated plants exceeded the control indicator by 11—29%. Conclusions. The use of systemic triazole fungicides to protect seedlings, improves the photosynthetic activity of plants and at the same time acts as a stress factor that activates protecting enzymes (catalase, peroxidase), which trigger the development of protective adaptive reactions of plants.

Growth Regulator Herbicides Prevent Invasive Annual Grass Seed Production

2010 ◽  
Vol 3 (1) ◽  
pp. 12-16 ◽  
Author(s):  
Matthew J. Rinella ◽  
Marshall R. Haferkamp ◽  
Robert A. Masters ◽  
Jennifer M. Muscha ◽  
Susan E. Bellows ◽  
...  
Keyword(s):  
Plant Growth ◽  
Seed Production ◽  
Growth Regulators ◽  
Growth Regulator ◽  
Cereal Crops ◽  
Growth Stages ◽  
Internode Elongation ◽  
Annual Grass ◽  
Stages Of Growth ◽  
Late Growth

AbstractAuxinic herbicides, such as 2,4-D and dicamba, that act as plant growth regulators are commonly used for broadleaf weed control in cereal crops (e.g., wheat, barley), grasslands, and noncroplands. If applied at late growth stages, while cereals are developing reproductive parts, the herbicides can reduce seed production. We tested whether growth regulators have this same effect on the invasive annual grass Japanese brome. The herbicides 2,4-D, dicamba, and picloram were applied at typical field use rates to Japanese brome at various growth stages in a greenhouse. Picloram reduced seed production nearly 100% when applied at the internode elongation, boot, or heading stages of growth, whereas dicamba appeared to be slightly less effective and 2,4-D was much less effective. Our results indicate it may be possible to control Japanese brome by using growth regulator herbicides to reduce its seed production, thereby depleting its short-lived seed bank.

Effects of Surface Energy on the Microstructures of Thin Sb Films

1990 ◽  
Vol 202 ◽  
Author(s):  
L. H. Chou ◽  
M. C. Kuo
Keyword(s):  
Electron Microscopy ◽  
Surface Energy ◽  
Grain Growth ◽  
Grain Orientation ◽  
Thermal Evaporation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Substrates ◽  
Transmission Electron ◽  
Diffraction Peaks

ABSTRACTThin Sb films have been prepared on glass substrates by rapid thermal evaporation. Films with thicknesses varied from 260 Å to 1300Å were used for the study. X-ray diffraction data showed that for films deposited at room substrate temperature, an almost random grain orientation was observed for films of 1300 Å thick and a tendency for preferred grain orientation was observed as films got thinner. For films of 260 Å thick, only two x-ray diffraction peaks--(003) and (006) were observed. After thermal annealing, secondary grains grew to show preferred orientation in all the films. This phenomenon was explained by surface-energy-driven secondary grain growth. This paper reports the effects of annealing time and film thickness on the secondary grain growth and the evolution of thin Sb film microstmctures. Transmission electron microscopy (TEM) and x-ray diffraction were used to characterize the films.

A Neoclassical Growth Model for Population Dynamics in a Homogeneous Habitat

2001 ◽  
Author(s):  
Peter Vadasz ◽  
Alisa S. Vadasz
Keyword(s):  
Experimental Data ◽  
Growth Model ◽  
Logistic Growth ◽  
Lag Phase ◽  
Growth Stages ◽  
Initial Growth ◽  
Neoclassical Model ◽  
Wide Range ◽  
Logistic Growth Model ◽  
Special Case

Abstract A neoclassical model is proposed for the growth of cell and other populations in a homogeneous habitat. The model extends on the Logistic Growth Model (LGM) in a non-trivial way in order to address the cases where the Logistic Growth Model (LGM) fails short in recovering qualitative as well as quantitative features that appear in experimental data. These features include in some cases overshooting and oscillations, in others the existence of a “Lag Phase” at the initial growth stages, as well as an inflection point in the “In curve” of the population size. The proposed neoclassical model recovers also the Logistic Growth Curve as a special case. Comparisons of the solutions obtained from the proposed neoclassical model with experimental data confirm its quantitative validity, as well as its ability to recover a wide range of qualitative features captured in experiments.

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