Type Of Microrelief Research Articles

Особенности микроморфологии и анатомии листа Populus tremula L. (sect. Populus) и P. nigra L. (sect. Aigeiros Duby, Salicaceae)

The micromorphology and anatomy of the epidermis of the abaxial surface of the leaf of Populus tremula L. (sect. Populus) and P. nigra L. (sect. Aigeiros Duby, Salicaceae) using light and scanning electron microscopes. The main cells of the epidermis of P. nigra according to N.A. Aneli are curvilinear curvilinear; the coefficient of tortuosity of the anticline walls is 14.3±0.3 µm/mm2; the area is from 437.5 to 1300.0 mm2 (average 820.9±39.9); P. tremula – sinuous, close to indented; 23.2± 0.4 µm/mm2; from 187.5 to 612.5 mm2 (average 351.7±12.6). The closing cells of the stomata in both species are lentil-shaped, multidirectional, located on the same level with the main ones. In P. tremula they are rather small (their length is 17.9± 0.4 microns), and in P. nigra they are larger (24.6± 0.4 microns). Stomata density in P. tremula ranged from 333 to 571 pcs/mm2, in P. nigra – from 100 to 183 pcs/ mm2. There is a folded (striate) microrelief near the stomata. In P. nigra, straight or sinuous folds ranging from 5 to 25 pieces diverge in different directions at a distance of 10 to 27 microns. Three types of microrelief were found. At P. tremula a small number of periosteal folds (from 3 to 17 pcs.) diverged perpendicular to the stomatal slit in different directions at a distance of ~ 10-20 microns.

MORPHOLOGY AND GENESIS OF GILGAI

Gilgai morphology, genesis, distribution and role in the landscape are described on the base of literature data and personal investigations. Gilgai is a specific type of microrelief, formed by slow uplift and intrusion of a subsoil material due to soil heaving resulted from alternating drying and wetting. In terms of genetic classification of landforms gilgai could be classified as hydrogenic microrelief, along with cryogenic, karst and suffosion microrelief. Gilgais may be identified and distinguished from other types of microrelief by the presence of slickensides – slip planes demonstrating the direction of the vertical and lateral shearing. Gilgai are mostly presented in tropical and subtropical regions, but were also found in Russia and the former USSR.

Self-organized technology of anisotropic etching of semiconductors for optoelectronics application

This paper is devoted to the investigation of self-organized microrelief morphology control for GaAs and InP substrates by varying the chemical anisotropic etching regime. The microstructure and the morphology of self-organized microrelief of quasigrating type were revealed by atomic force microscopy (AFM) technique. This type of microrelief allows in particular to obtain additional photosensitivity enhancement for Schottky barrier structures due to surface plasmon polariton excitation. The optical and photoelectric characteristics of Au/GaAs (InP) barrier structures were investigated in the range of fundamental absorption of light and the optimum microrelief processing were selected.

Ultraviolet responsivity control in Schottky barrier heterostructures with textured interface

This paper is devoted to ultraviolet responsivity control in Schottky barrier heterostructures based on GaAs and InP with textured interface. The influence of microrelief morphology and of its geometrical parameters on optical properties and photoresponse characteristics (spectral and polarization) has been investigated. Both random microrelief obtained by chemical anisotropic etching of semiconductor and microrelief of grating type formed by holographic etching were used. The optical and photoelectric characterization of heterostructures with textured interface allowed us to determine the most promising type of microrelief, and to define the mechanisms of the photosensitivity enhancement. Specifically, the role of surface polariton excitation as a mechanism of photoresponse increasing was treated.

Texturized interface as a basis of surface-barrier heterostructure for solar cells application

Simulation of the photocurrent of surface-barrier structures (SBS) with texturized interface has been performed on the basis of obtained theoretical expression for internal quantum efficiency of homogeneous SBS and the model of parallelly connected diodes. The role of various sources of recombination losses (in the semiconductor, at the interface and due to the emission of majority carriers into the metal) in solar energy convertors has been analyzed. The complex method of characterization of SBS with texturized interface is proposed that includes an analysis of optical, electric and photoelectric characteristics. The possibility to increase the photosensitivity of the Au/GaAs SBS due to texturization and sulfur passivation of the interface for two types of microrelief (dendritic and quasigrating) obtained by wet anisotropic etching has been investigated. The morphology and statistical geometric characteristics of the interface were investigated by atomic force microscopy (AFM). The obtained results allowed to determine the change of optical and electronic (recombination) parameters of the interface caused by the used processing (texturization, passivation).

Characterization of rainfall - microrelief interactions with runoff using parameters derived from digital elevation models (DEMs)

The main objective of this study was to investigate how the interactions between rainfall energy and microrelief affect soil surface sealing and runoff. Furthermore, several roughness indices and geostatistical procedures were tested for their ability to characterize microrelief. Runoff boxes filled with soil from the plough layer of a silty Luvisol were subjected to simulated rainfall. Two types of microrelief (rough and fine) were tested at two rainfall intensities (30 and 60 mm/h). A photogrammetric technique was used to develop digital elevation models (DEMs) of the soil surface before and after rainfall with a resolution in height of 0.2 mm and a grid spacing of 2 mm. The random roughness coefficient according to Currence & Lovely (1970) was found to be sensitive to surface microrelief variations. Semivariograms of the data indicated that big clods were the main elements determining microrelief and the ratio of total surface are to map area. The observed variations in runoff as a function of microrelief were best explained by rainfall energy per total surface area and by the relative contribution of the effective normal component of kinetic energy with respect to the impact angle of raindrops. Microdepression storage was only 0.6 mm or less and was found to be negligible in terms of runoff.

Sedimentary Features and Nearshore Processes of Arctic and Sub-Arctic Beaches: ABSTRACT

Arctic beaches show characteristic sedimentary features that readily distinguish them from beaches in more temperate zones. Along the Alaska coastline in the eastern Arctic and subarctic regions of the Bering Sea, many exotic microtopographic structures may persist throughout summer, if spring and summer weather conditions are mild enough. On prograding sections of the coast, similar features might be preserved in the stratigraphic cross section of the beach. Microrelief features develop in spring and early summer as a result of dynamic processes associated with breakup of sea ice and thawing of kaimoo, permafrost, snow banks, and stranded blocks of ice. On the beach 2 different types of microrelief occur. Along the backshore and the upper foreshore, small streamlets and mud flows fed by melting snow and thawing permafrost produce micro-outwash and microdeltaic deposits. In the swash zone, movement of grounded sea ice by wind and waves produces ice-push ridges; melting of kaimoo ice leaves a kaimoo ridge, and melting of stranded gravel- and sand-rich brash ice creates sea-ice kettles and sea-ice sand and gravel cones. Within the nearshore areas, close to the shoreline, sea ice locally scours the bottom sediment into small randomly oriented ridges and troughs. Farther offshore, small randomly spaced hummocks of coarse sand and gravel form where ice-rafted sediment drops from grounded or stabilized melting sea ice. End_of_Article - Last_Page 620------------

Electron fractographic investigation of the fracture of heat treated low-alloy steel

1. In improved 10G2S steel one finds basically the same type of relief as in the hot-rolled steel. However, due to the finer structure of the ferrite matrix the relief is finer and the transition from ductile to brittle microrelief occurs at lower temperatures. One also observes fracture along the boundaries of the grains and subgrains of the ferrite matrix. 2. In the transition from brittle to ductile fracture the area occupied by brittle elements of microrelief decreases and the number of areas with ductile relief increases. 3. Fractures with the same macrostructure may have quite different types of microrelief.