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51.
52.
Persistent scatterer interferometry (PSI) is a major advancement in radar interferometry for detecting and monitoring land deformation. PSI is the most advanced class of differential interferometric synthetic aperture radar (DInSAR) techniques. The technique conquers the main drawbacks of the conventional DInSAR technique by identifying radar targets having stable backscattering characteristics in time. These targets are termed as persistent scatterers (PSs). The higher the number of PSs for a study area the higher the accuracy of the results will be, which is most common for deformation analysis in urban areas. However, for non-urban or highly de-correlated areas, PSs density collapses significantly, which needs to increase for optimal results. For this purpose, partially coherent/distributed scatterers (DSs) are being exploited in addition to the PSs. The field surface of this study is one of the copper-rich mining belts in India, which consists of two major underground metal mines. Scatterer characterziation of the field surface under study suggests that most of the scatterers are DSs and very few scatterers under the influence of the mining zone are PSs. In addition to this, a preliminary investigation of deformation characteristics of the field surface under study reveals that the spatial extent of deformation is small/localized along with slow and non-linear deformation. Keeping in view scatterer and deformation characteristics of the field surface under study, in this research paper, a Quasi-Persistent Scatterer based PSI approach has been applied using high-resolution TerraSAR-X interferometric data stack (10 images) to generate deformation time series and deformation velocity. Furthermore, results obtained from the applied PSI approach and ground-based observations (using GNSS) have shown good agreement with each other, in the order of ?5.20?mm/year (LOS) and ?5.38?mm/year (subsiding), respectively. 相似文献
53.
Jing Li Ping Liu Yan Qu Tingdi Liao Bin Xiang 《International Journal of Hydrogen Energy》2018,43(5):2601-2609
The number of exposed active sites in a catalyst plays a key role in determining its catalytic performance. However, the aggregation effect in nanostructured catalysts causes much less reactive sites exposed. In this paper, we report a novel structure of WSe2/rGO with highly exposed WSe2 active edge sites by uniformly imbedding the rGO between each WSe2 nanosheets. With the introduction of rGO, the electron transport property of the WSe2/rGO hybrid structure has also been enhanced. The structure and composition of the samples were investigated by the X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. Our electrochemical characterizations confirm that the WSe2/rGO hybrid structure exhibits enhanced electrochemical catalytic performance with a Tafel slop of 85 mV/dec for HER, much smaller than that of the pure WSe2. 相似文献
54.
Milinda Pattanayak Md Nadim F Hoque Zhaoyang Fan Ayrton A. Bernussi 《Science and Technology of Advanced Materials》2018,19(1):693-701
We report large amplitude modulation waveforms as large as ~ 10 V using vanadium dioxide micro-channel devices operating under current-controlled conditions. The self-sustained electrical oscillations were generated by controlling the applied current in the negative differential resistance region of the investigated devices. An appropriate value of internal capacitance was achieved as parasitic capacitance in the device structure to stabilize the electrical oscillations. This eliminates the need of an external pulsed source or any external passive component connected to the micro-channel devices. Amplitude and frequency of the oscillation were tuned by illuminating the device micro-channel with an external laser. An equivalent circuit model was developed to simulate the waveforms. A good agreement between experiment and simulation was verified. 相似文献
55.
The titanium carbides are potential candidates to achieve both high hardness and refractory property. We carried out a structural search for titanium carbides at three pressures of 0 GPa, 30 GPa and 50 GPa. A phase diagram of the Ti-C system at 0 K was obtained by elucidating formation enthalpies as a function of compositions, and their mechanical and metallic properties of titanium carbides were investigated systematically. We also discussed the relation of titanium concentration to the both mechanical and metallic properties of titanium carbides. It has been found that the average valence electron density and tractility improved at higher concentrations of titanium, while the degree of covalent bonding directionality decreased. To this effect, the hardness of titanium carbide decreases as the content of titanium increases. Our results indicated that the titanium content significantly affected the metallic properties of the Ti-C system. 相似文献
56.
57.
Marijana Đaković 《Crystallography Reviews》2020,26(2):69-100
Designing crystalline solids with improved properties or performances remains a challenging task, despite great strides that have been made within the field of crystal engineering since its birth several decades ago. Herein, we are bringing examples that illustrate recent successes in taking supramolecular synthetic guidelines from the organic crystal engineering and adjusting those to metal-containing systems, particularly to the lower-dimensional ones. The versatility of calculated molecular electrostatic potential (MEP) as a new crystal engineering tool is demonstrated. 相似文献
58.
59.
ABSTRACT Aqueous solutions of 4,4′-(1,2-ethanediyldinitrilo)bis-(2-pentanone) (EDDBP) have been used in a novel green procedure for the physical modification of silica gel (SG) for solid-phase extraction and preconcentration of Ni(II) ion. Optimization experiments were carried out at 301 ± 1 K by batch technique. The EDDBP-modified SG was characterized using X-ray Diffraction Spectroscopy (XRD) and Brunaeur-Emmett-Teller (BET) determinations. The adsorption isotherm and kinetic models indicated a physisorption process. The modified SG showed moderate to high adsorption capacity values for Ni(II) ion (~98% removal efficiency) at pH 8. A sorption mechanism for Ni(II) chelation with EDDBP-modified-SG was proposed. These results suggest the procedure has advantages. 相似文献
60.
Wenping Zou Khoa Le Prof. Melissa L. Zastrow 《Chembiochem : a European journal of chemical biology》2020,21(9):1356-1363
CreiLOV is a flavin-binding fluorescent protein derived from the blue-light photoreceptor protein family that contains light-oxygen-voltage (LOV) sensing domains. Flavin-binding fluorescent proteins represent a promising foundation for new fluorescent reporters and biosensors that can address limitations of the well-established green fluorescent protein (GFP) family. Flavin-binding fluorescent proteins are smaller than GFPs, are stable over a wider pH range, offer rapid chromophore incorporation, and are oxygen-independent so can be applied to live anaerobic organisms. Among the flavin-binding fluorescent proteins, CreiLOV has a high quantum yield and excellent photophysical properties, making it promising for cellular applications. Here, we investigated the suitability of CreiLOV as an intensity- and fluorescence-lifetime-based metal sensor. CreiLOV selectively binds copper(II) over other biologically relevant metals with low-micromolar affinity, resulting in fluorescence quenching and a decrease in the fluorescence lifetime that can be observed in cuvettes and live bacterial cells. 相似文献