Prominent Orientations Research Articles

Structural, Optical and Morphological Properties of Ag Doped CuO Thin Films Produced by Spin Coating Method

Son yıllarda, bakır (II) oksit (CuO) ince filmler benzersiz fiziksel ve kimyasal özelliklerinden dolayı araştırmacılardan büyük ilgi görmektedir. Bu çalışmada, gümüş (Ag) katkılı bakır oksit ince filmleri, çeşitli katkı oranlarında dönel kaplama tekniği uygulanarak cam alttaş üzerinde üretildi. Farklı gümüş katkısına bağlı olarak hazırlanan ince filmlerin yapısal, morfolojik ve optik özellikleri sırasıyla X-ışını kırınımmetresi (XRD), taramalı elektron mikroskobu (SEM) ve UV-VİS spektrofotometrisi kullanılarak incelenmiştir. Ag katkılı CuO filmlerinin XRD desenleri, tüm ince filmlerin polikristal doğaya sahip tenorite yapılı olduğunu göstermiştir. En belirgin yönelimler için stres, düzlemler arası mesafe, kristal büyüklüğü ve dislokasyon yoğunluğu X-ışını kırınımı analizi kullanılarak hesaplandı. En fazla kristal büyüklüğü değeri (111) tercihli yönelimi için katkısız CuO filmine ait olup yüksek kalitede kristalliğe sahip olduğu söylenilebilir. SEM ölçümü, film yüzeylerinde çok küçük bir topaklama ile beraber, ince film yüzeylerinde homojen olarak dağılmış nanoyapı parçacıkların varlığını göstermektedir. SEM görüntülerinin sonucu atomik kuvvet mikroskopu (AFM) ile benzer yapıdadır. EDX bağlantılı FEI Quanta 250 FEG taramalı elektron mikroskopu ile filmlerin tabaka kalınlığı yaklaşık olarak 460 nm civarındadır. Ayrıca, elde edilen örneklerin optik özellikleri, UV-VİS spektrofotometrisi kullanılarak bant aralığı ölçümleri, soğurma ve geçirgenlik değerleri türünden analiz edildi. İnce filmlerin ultraviyole-görünür ölçümleri, oda sıcaklığında CuO ince filminin geçirgenlik ve soğurma değerlerinin Ag katkılanma sonucu değiştiği görülmektedir. Aynı şekilde enerji bant aralığı, artan Ag katkı oranına bağlı olarak değişti.

Photocatalytic degradation of methylene blue dye using F doped ZnO/polyvinyl alcohol nanocomposites

The photocatalytic activity of fluorine-doped zinc oxide (ZnO-F) nanoparticles (NPs) is improved with the assistance of polyvinyl alcohol (PVA). ZnO-F NPs were synthesized through a co-precipitation reaction of zinc nitrate and ammonium fluoride. The obtained ZnO-F NPs were capped with various amounts of PVA, utilizing a facile solution-based approach. XRD patterns showed that PVA polymer didn’t alter the crystallinity properties of ZnO NPs and its hexagonal wurtzite structure with prominent orientations of (100), (002), and (101) was preserved. While UV–Vis spectra revealed that the optical band of nanocomposites varies with increasing amounts of PVA from 2.10 eV for ZnO-F NPs to 2.13 eV for 4% PVA loaded-ZnO-F. The data showed when the weight ratio of PVA polymer with respect to the neat ZnO NPs is fixed at 4% during the synthesis process, the highest photocatalytic activity for hybrid NPs is achieved.

Recency of Faulting and Subsurface Architecture of the San Diego Bay Pull-Apart Basin, California, USA

In Southern California, plate boundary motion between the North American and Pacific plates is distributed across several sub-parallel fault systems. The offshore faults of the California Continental Borderland (CCB) are thought to accommodate ∼10–15% of the total plate boundary motion, but the exact distribution of slip and the mechanics of slip partitioning remain uncertain. The Newport-Inglewood-Rose Canyon fault is the easternmost fault within the CCB whose southern segment splays out into a complex network of faults beneath San Diego Bay. A pull-apart basin model between the Rose Canyon and the offshore Descanso fault has been used to explain prominent fault orientations and subsidence beneath San Diego Bay; however, this model does not account for faults in the southern portion of the bay or faulting east of the bay. To investigate the characteristics of faulting and stratigraphic architecture beneath San Diego Bay, we combined a suite of reprocessed legacy airgun multi-channel seismic profiles and high-resolution Chirp data, with age and lithology controls from geotechnical boreholes and shallow sub-surface vibracores. This combined dataset is used to create gridded horizon surfaces, fault maps, and perform a kinematic fault analysis. The structure beneath San Diego Bay is dominated by down-to-the-east motion on normal faults that can be separated into two distinct groups. The strikes of these two fault groups can be explained with a double pull-apart basin model for San Diego Bay. In our conceptual model, the western portion of San Diego Bay is controlled by a right-step between the Rose Canyon and Descanso faults, which matches both observations and predictions from laboratory models. The eastern portion of San Diego Bay appears to be controlled by an inferred step-over between the Rose Canyon and San Miguel-Vallecitos faults and displays distinct fault strike orientations, which kinematic analysis indicates should have a significant component of strike-slip partitioning that is not detectable in the seismic data. The potential of a Rose Canyon-San Miguel-Vallecitos fault connection would effectively cut the stepover distance in half and have important implications for the seismic hazard of the San Diego-Tijuana metropolitan area (population ∼3 million people).

Control of pre-existing fabric in fracture formation, reactivation and vein emplacement under variable fluid pressure conditions: an example from Archean greenstone belt, India

Abstract. Most of the upper crustal fluid flows are strongly influenced by the pre-existing fractures/foliations in the rocks under a certain state of tectonic stress and fluid pressure condition. In the present study, we analyzed a wide range of crosscutting fractures that are filled with quartz veins of variable orientations and thicknesses, from the gold-bearing massive metabasalts (supracrustals) of the Chitradurga Schist Belt adjacent to the Chitradurga Shear Zone (CSZ), Western Dharwar Craton, southern India. The study involves the following steps: (1) analyzing the internal magnetic fabric, using anisotropy of magnetic susceptibility (AMS) studies, and determining strength of the host metabasalts, (2) quantifying the fluid pressure condition through lower hemisphere equal area projection of pole to veins by determining the driving pressure ratio (R′), stress ratio (ϕ), and susceptibility to fracturing, and (3) deciphering the paleostress condition using fault-slip analysis. We interpret the NNW–SSE to NW–SE (mean 337/69∘ NE) oriented magnetic fabric in the rocks of the region as having developed during regional D1/D2 deformation on account of NE–SW shortening. However, D3 deformation manifested by NW–SE to E–W shortening led to the sinistral movement along CSZ. As a consequence of this sinistral shearing, fractures with prominent orientations formed riedel shear components, with CSZ as the shear boundary. Subsequently, all the pre-existing fabrics along with the riedel shear components were reactivated and vein emplacement took place through episodic fluid pressure fluctuation from high to low Pf at shallow depth (∼ 2.4 km). However, NNW–SSE orientations were prone to reactivate under both high- and low-Pf conditions, thereby attaining maximum vein thickness along these orientations. The deduced paleostress from fault-slip analysis along with the kinematics of the fractures and veins are in good agreement with previously estimated regional tectonics. Thus, integrating multiple domains of studies helps in the logical interpretation of fluid flow conditions and vein emplacement mechanisms in the study area that has not been ventured before.

Direction Selective Contour Detection for Salient Objects

The active contour model is a widely used technique for automatic object contour extraction. Existing methods based on this model can perform with high accuracy, even in the case of complex contours, but challenging issues remain, like the need for precise contour initialization for high curvature boundary segments or the handling of cluttered backgrounds. To deal with such issues, this paper presents a salient object extraction method, the first step of which is the introduction of an improved edge map that incorporates edge direction as a feature. The direction information in the small neighborhoods of image feature points is extracted, and the images’ prominent orientations are defined for direction-selective edge extraction. Using such improved edge information, we provide a highly accurate shape contour representation, which we also combine with texture features. The principle of the paper is to interpret an object as the fusion of its components: its extracted contour and its inner texture. Our goal in fusing textural and structural information is twofold: it is applied for automatic contour initialization, and it is also used to establish an improved external force field. This fusion then produces highly accurate salient object extractions. We performed extensive evaluations, which confirm that the presented object extraction method outperforms parametric active contour models and achieves higher efficiency than the majority of the evaluated automatic saliency methods.

Texture Analysis of Thin In2O3:Sn Films Prepared by Direct-current and Radio-frequency Magnetron-sputtering

Thin In2O3:Sn (ITO) films prepared by radio-frequency (rf) or direct-current (dc) magnetron-sputtering and in central or peripheral position relative to the target were characterized by x-ray diffractograms and pole figures. The diffractograms were normalized with the powder diffraction intensities of the target. In the normalized diffractograms, a random texture level and preferred orientations can be distinguished. The pole figures are represented by normalized χ-scans that are modeled as a sum of Gaussian curves. The centers of the Gaussian curves are consistent with the prominent orientations of the normalized diffractograms. The textures of the rf-sputtered films in the central and the peripheral position are similar, showing strong contributions from (211)-planes. The texture of dc-sputtered samples is dominated by (400) and (411) planes. In the peripheral sample, the distribution of (400)- and (411)-oriented grains is shifted towards the incidence angle of the particle flux and the frequency of the (222)-grains is suppressed below the random texture level. The results are discussed with reference to a model of incorporation of interstitial oxygen into the growing films.

Subglacial meltwater channels at Thurstaston Hill, Wirral and their significance for Late Devensian ice sheet dynamics

Small-scale bedrock features of glacial meltwater erosion such as Nye channels are rare in Britain and these features do not appear to have been previously described from England. In this paper we describe the range of glacial meltwater features developed at Thurstaston Hill, Wirral. The forms at this site are carved in Triassic sandstone and include a spectacular three-dimensional linked plunge pool-Nye channel cavity system. Across the site as a whole, Nye channels are the most common landform. The channels are mostly linear and incised in bedrock to a depth of up to 1 m. These features show two prominent orientations, one parallel to regional ice flow during the last (Late Devensian) glaciation and another transverse to ice flow. There are three important implications for the Late Devensian glaciation of the area: (i) the ice sheet was relatively thin and heavily crevassed at the time when the system was created; (ii) deglaciation was characterized by active ice with no evidence for ice stagnation; and (iii) deglaciation was achieved under warm-based conditions.

Crystal structure of 1,4-bis[β(9-anthryl)ethyloxycarbonyl]piperazine dichloromethane solvate, (C38H34N2O4)(CH2Cl2)

Monoclinic, C12 1 /c1, a=26.930, b=11.713, c=11.614A, β=114.50°, Z=4, R=0.064. The molecule lies on a centre of symmetry. The second half of the molecule is generated by symmetry operation -x, 1-y, -z. The dichloromethane lies on a twofold axis and is disordered. The two most prominent orientations were refined. The H-atoms of the solvent molecule were not located

Regional fracture patterns east of the Alpine Fault between the Fox and Franz Josef Glaciers, Westland, New Zealand

Abstract A study of lineaments traced from aerial photographs shows three prominent orientations in the region immediately east of the Alpine Fault between the Fox and Waiho valleys, Westland, New Zealand. One set trends about 025°, parallel to the foliation in the Alpine Schist. A second, minor set of lineaments trends 130° and may be related to extension fractures. The third lineament set trends east-west. Detailed fieldwork on prominent east-west faults in the Waiho valley shows that they are dextral strike-slip faults, with evidence for additional late-stage normal displacement. All of the faults investigated exhibit only small displacements. Fault orientations are consistent with theoretical and geodetically measured regional strain east of the Alpine Fault.

Shock-Metamorphic Features in Two Meteorite Impact Structures, Southeastern Libya

Shock-metamorphic effects in sandstone samples from two circular structures about 80 km apart in southeastern Libya demonstrate that these structures formed by meteorite impact. The smaller structure is about 2.8 km in diameter, and the larger is 11.5 km in diameter. Both structures occur in flat-lying Nubian Sandstone (Early Cretaceous) that is intensely disturbed within the structures. Sandstone specimens from both show extensive microscopic shock effects in quartz, including cleavage and planar features (shock lamellae), with prominent orientations in the {0001}, {1¯122}, and {1¯011} planes. A reduced development of planes parallel to {1¯013} and {1¯012}, also typical of shocked Coconino Sandstone from Meteor Crater, Arizona, indicates that slightly porous or cemented sandstone shows significantly different responses to shock waves than massive crystalline rocks show. Both Libyan structures are post-Nubian in age. Their similar degree of erosion suggests a simultaneous origin by a double impact.

Twinning of Erbium Oxide Single Crystals in the Electron Microscope

During the course of investigations directed towards the preparation of concentrated solid solutions of rare earth oxides in MgO host crystals, the occasion arose where polycrystalline hep erbium metal foils vapor deposited onto cleaved NaCl substrates at room temperature (in a nominal vacuum prior to vaporization of 10−8-10−9 Torr) were observed by transmission electron microscopy. It was discovered that when an intermittent flash evaporation technique was used in the vaporization of erbium (99.95%) from high purity tungsten boats, tiny single crystals of various prominent surface orientations were formed in association with the erbium matrix, which differed significantly in structure from the matrix. The surface orientations observed for these crystals, which ranged in size from a few hundred Angstroms to a few microns on a side, were (100), (110), and (111). A rather striking feature of these crystals was the fact that if the electron beam was focused on an individual crystal, particularly in (100) orientation, the crystal began to twin from the edges by the apparent motion of “twinning dislocations” in the {110} planes; with subsequent twinning of the entire crystal taking place after a few seconds exposure at high beam intensity.