Mud volcanoes and structural development on Shah Deniz

Shah Deniz is a large four-way dip closed structure in the South Caspian located approximately 35 km to the southeast of Bahar and 70 km southwest of the Guneshli–Chirag–Azeri (GCA) Oil Field. A large 3D survey (800 km²) was acquired over the PSA area in the summer of 1997 and the first exploration well was spudded in the summer of 1998, the second in the summer of 1999. 3D data has shown many interesting details about the development of mud volcanoes and associated features over Shah Deniz and this information has been used to help in the drilling of exploration wells. Mud volcano features on Shah Deniz range from small (hundreds of square-meter) cones to a large “collapse caldera” (10–15 km²) that overlies much of the northern part of the crest. All mud volcano features appear to be associated with the crests of deep (pre-Maykop) structural highs. Isochron maps of seismic intervals within the Quaternary and Apsheron show that the Shah Deniz structure started to form at around the end of Productive Series deposition and continued through into the upper Quaternary. Mud volcano activity did not begin until middle Apsheron. There is therefore a delay between the start of structural development and the appearance of mud volcano flows of approximately 0.5 million years. Mud volcanoes appeared first at the southern end of the structure, while the major mud volcano on the crest did not start to develop until slightly later within the Apsheron. This is consistent with the observation that the structure initially developed in the south, before the major direction of shortening, NW–SE, seen today, became more dominant in the Mid-Apsheron. The mud volcano flows that are relatively high amplitude seismically can be clearly seen on the seismic, using voxel-based volume visualization, when stratigraphy parallel time slices are viewed. The opacity of the amplitude spectrum can be varied such that any particular amplitude ranges can be highlighted. This technique has shown moderate to high amplitude flows coming from the major central mud volcano that have a lateral extent of up to 17 km and widths of around 0.5 km. The impact of seabed topography can also be seen on the flows as well as the different characteristics of the individual mud volcanoes.     

Zone-boundary optimization for direct laser writing of continuous-relief diffractive optical elements

Enhancing the diffraction efficiency of continuous-relief diffractive optical elements fabricated by direct laser writing is discussed. A new method of zone-boundary optimization is proposed to correct exposure data only in narrow areas along the boundaries of diffractive zones. The optimization decreases the loss of diffraction efficiency related to convolution of a desired phase profile with a writing-beam intensity distribution. A simplified stepped transition function that describes optimized exposure data near zone boundaries can be made universal for a wide range of zone periods. The approach permits a similar increase in the diffraction efficiency as an individual-pixel optimization but with fewer computation efforts. Computer simulations demonstrated that the zone-boundary optimization for a 6 microm period grating increases the efficiency by 7% and 14.5% for 0.6 microm and 1.65 microm writing-spot diameters, respectively. The diffraction efficiency of as much as 65%-90% for 4-10 microm zone periods was obtained experimentally with this method.     

Voltage-controlled narrowband and wide, variable-range four-segment quartz crystal oscillator

In this work, our goal is to develop a voltage-controlled variable-frequency quartz crystal oscillator with narrowband response, wide, variable frequency range and the capacity to oscillate across the series resonance frequency using a four-segment configuration of a quartz crystal oscillator. In conventional quartz oscillators, the quartz resonator is inserted in the feedback loop between the input and the output of the active circuit, providing sufficient gain and the phase relation. In the oscillator developed here, the quartz crystal resonator is inserted between the loop circuit and the ground potential. The performance of the voltage-controlled variable-frequency oscillator is demonstrated across the series resonance frequency.     

Structure–Transport Correlation Reveals Anisotropic Charge Transport in Coupled PbS Nanocrystal Superlattices

The assembly of colloidal semiconductive nanocrystals into highly ordered superlattices predicts novel structure-related properties by design. However, those structure–property relationships, such as charge transport depending on the structure or even directions of the superlattice, have remained unrevealed so far. Here, electric transport measurements and X-ray nanodiffraction are performed on self-assembled lead sulfide nanocrystal superlattices to investigate direction-dependent charge carrier transport in microscopic domains of these materials. By angular X-ray cross-correlation analysis, the structure and orientation of individual superlattices is determined, which are directly correlated with the electronic properties of the same microdomains. By that, strong evidence for the effect of superlattice crystallinity on the electric conductivity is found. Further, anisotropic charge transport in highly ordered monocrystalline domains is revealed, which is attributed to the dominant effect of shortest interparticle distance. This implies that transport anisotropy should be a general feature of weakly coupled nanocrystal superlattices.     

Nanocrystalline β-Ti alloy with high hardness,low Young's modulus and excellent in vitro biocompatibility for biomedical applications

High strength, low Young's modulus and good biocompatibility are desirable but difficult to simultaneously achieve in metallic implant materials for load bearing applications, and these impose significant challenges in material design. Here we report that a nano-grained β-Ti alloy prepared by high-pressure torsion exhibits remarkable mechanical and biological properties. The hardness and modulus of the nano-grained Ti alloy were respectively 23% higher and 34% lower than those of its coarse-grained counterpart. Fibroblast cell attachment and proliferation were enhanced, demonstrating good in vitro biocompatibility of the nano-grained Ti alloy, consistent with demonstrated increased nano-roughness on the nano-grained Ti alloy. Results suggest that the nano-grained β-Ti alloy may have significant application as an implant material in dental and orthopedic applications.     

4-D pattern structure features by three stages clustering algorithm for image analysis and classification

An approach for decomposition of visual image by clustering, pattern analysis and classification by structure features is considered. Hierarchical clusters such as rectangles, closed regions and integrated areas are objects of investigation. By hierarchically constructed fragments, the 4-D pattern structure features are formulated. To reduce the clustering algorithm complexity, the scanning area approach is proposed. The results of pattern analysis and classification by structure features for some images are presented.     

Cytoskeleton Rearrangements Modulate TRPC6 Channel Activity in Podocytes

The actin cytoskeleton of podocytes plays a central role in the functioning of the filtration barrier in the kidney. Calcium entry into podocytes via TRPC6 (Transient Receptor Potential Canonical 6) channels leads to actin cytoskeleton rearrangement, thereby affecting the filtration barrier. We hypothesized that there is feedback from the cytoskeleton that modulates the activity of TRPC6 channels. Experiments using scanning ion-conductance microscopy demonstrated a change in migration properties in podocyte cell cultures treated with cytochalasin D, a pharmacological agent that disrupts the actin cytoskeleton. Cell-attached patch-clamp experiments revealed that cytochalasin D increases the activity of TRPC6 channels in CHO (Chinese Hamster Ovary) cells overexpressing the channel and in podocytes from freshly isolated glomeruli. Furthermore, it was previously reported that mutation in ACTN4, which encodes α-actinin-4, causes focal segmental glomerulosclerosis and solidifies the actin network in podocytes. Therefore, we tested whether α-actinin-4 regulates the activity of TRPC6 channels. We found that co-expression of mutant α-actinin-4 K255E with TRPC6 in CHO cells decreases TRPC6 channel activity. Therefore, our data demonstrate a direct interaction between the structure of the actin cytoskeleton and TRPC6 activity.     

Synthesis,structure and photocatalytic properties of nanoparticles from a carbon-containing composite based on silicon oxide modified with titanium dioxide

A pulsed plasmochemical method was used to obtain carbon-containing nanocomposites based on silicon oxide modified with titanium dioxide. The material contained a Si_xC_yO_z carrier with an average size of 50–150?nm and a shell of fine particles with an average size of 5–10?nm. The phase composition and morphology of the synthesized composites was studied by X-ray diffraction and transmission electron microscopy. The optical and photocatalytic properties of the nanoparticles from the carbon-based composite based on silicon oxide encapsulated in titanium dioxide were studied. The synthesized composite showed a high photocatalytic activity due to the decomposition of methylene blue under the influence of visible light in the wavelength range of 460–630?nm.     

Plasma‐beam alignment of passive liquid crystals (Invited Paper)

Abstract— A plasma‐beam process, developed for the alignment of liquid crystals (LC) in electro‐optic applications, has been successfully applied to align “non‐standard” LC, such as crystalline materials with LC phases at elevated temperatures and reactive mesogenes. In addition to the high alignment quality of the materials, there is no need for an intermediate layer between the substrate and the LC layer. Furthermore, the construction of our source simplifies the alignment procedure of large‐area rigid substrates and the roll‐to‐roll processing of flexible films. This method opens new horizons for optical retarders and polarizers, as well as anisotropic semiconducting films for organic electronics.