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131.
M. Y. A. Rahman A. A. Umar L. Roza M. M. Salleh 《Journal of Solid State Electrochemistry》2012,16(12):3947-3952
The morphology of photovoltaic material is able to influence of the performance of photoelectrochemical cell. Polyvinylpyrrolidone (PVP), cetyltrimethylammonium bromide (CTAB), and hexamethylenetetramine (HMT) surfactant were used to modify the morphology nanostructure of TiO2 films by a simple technique, namely, liquid phase deposition during their growth process. It was found that the untreated surfactant TiO2 film produces the morphology with the mixture nanosphere and nanoflower. The film treated with PVP, CTAB, and HMT produce the nanostructure shape of nanoflower, nanowire, and nanorod, respectively. These TiO2 samples were utilized as photovoltaic materials in a photoelectrochemical cell of ITO/TiO2/electrolyte/platinum. It was found that the photovoltaic parameters such as short-circuit current density (J sc), open-circuit voltage (V oc) and fill factor are influenced by the morphology in terms of shape and particle size of the TiO2 nanostructure. The cell utilizing the TiO2 nanowire treated with PVP possesses the highest J sc and V oc of 0.100 mAcm?2 and 0.44 V. The length of the TiO2 nanowire is 6?±?2 nm, while the cell with the untreated surfactant TiO2 sample demonstrates the lowest performance. It was also found that the J sc and V oc increase with the decrease in the length of the TiO2 nanostructures. The smallest length of TiO2 possesses the best interfacial contact at TiO2/electrolyte containing iodide/triiodide redox couple. Thus, the redox reaction is optimized at this interface. 相似文献
132.
133.
Kaleem Ahmad Walid Tawfik Wazirzada A. Farooq Jagdish P. Singh 《Applied Physics A: Materials Science & Processing》2014,117(3):1315-1322
In this work, alumina (Al2O3) containing different volume % of titanium carbide (TiC) ranging from 0 to 30 were consolidated by the novel spark plasma sintering. The spectroscopic analysis of the plasma generated by irradiation of laser Nd:YAG (λ = 1,064 nm) on different concentrations of the composites in air atmospheric pressure was performed. The qualitative examination of the composites confirms the presence of aluminum, titanium, and carbon as major elements, while magnesium and sodium have been found as minor trace elements. Plasma parameters were estimated by assuming the LTE conditions for optically thin plasma. The electron density and temperature were evaluated by using the Stark broadening and intensity of selected aluminum emission lines, respectively. The addition of TiC to Al2O3 shows a linear behavior with plasma temperature corroborated by the calibration curve of Ti in the composites. The results suggest that calibration curve between plasma temperature and the composites can be used to estimate different concentrations of TiC in Al2O3 without analyzing the whole elements in the composites and thus opens up new applications of LIBS in ceramic industry. 相似文献
134.
W. Aslam Farooq M. Atif Syed Mansoor Ali Amanullah Fatehmulla M. Aslam 《Optics and Spectroscopy》2014,117(3):386-391
TiO2 thin film has been widely used as photoelectrode in dye-sensitized solar cells. It can also be used in quantum dot synthesized solar cells. Study of its effects in different spectrum of light is important for its use in solar cells. We have reported effects of 1064 nm laser on the surface morphology, structural and optical properties of nanostructured TiO2 thin film deposited on glass substrates using sol-gel spin coating technique. Q-Switched Nd:YAG pulsed laser at various power densities is used in this study. Surface morphology of the film is investigated using X-ray diffraction (XRD) and atomic force microscopy technique. The XRD pattern of as deposited TiO2 thin film is amorphous and after laser exposure it became TiO2 anatase structure. Atomic force microscopy of the crystalline TiO2 thin film shows that the grain size increases by increasing laser power density. The calculations of the band gap are carried out from UV/Visible spectroscopy measurements with JASCO spectrometer. For laser power density of 25 MW/cm2 there is an increase in the transmission and it decreases at the value of 38 MW/cm2 and band gap decreases with increasing laser power density. Photoluminescence spectra of the crystalline TiO2 thin film indicate two broad peaks in the range of 415 and 463 nm, one for band gap peak (415 nm) and other for oxygen defect during film deposition process. 相似文献
135.
W. A. Farooq S. Mansoor Ali J. Muhammad S. Danish Ali M. Atif 《Optics and Spectroscopy》2014,116(3):473-478
The effects of laser irradiation on the surface, structure and optical properties of SnO thin films deposited on glass substrates using electron beam evaporation, are investigated. The thin film samples are irradiated using fundamental beam at 1064 nm from Q-switched Nd:YAG pulsed laser with different power densities. Structural morphology of the film is investigated using XRD patterns and AFM image. Both XRD pattern and AFM image show increase in grain size of the film with increasing laser power density. Other optical phenomena, photoluminescence emission, transmission, refractive index determination and optical band gaps calculations are also carried out at various laser power densities. Results from all these investigations reveal expansion in grain size of the crystalline SnO thin film with increasing laser power density. 相似文献
136.
Desorption of Asphaltenes from Silica-Coated Quartz Crystal Surfaces in Low Saline Aqueous Solutions
The quartz crystal microbalance (QCM) was used to study desorption of asphaltenes from silica-coated quartz crystals upon exposure to various aqueous low saline solutions of different salt concentrations and cationic valency. Ultraviolet (UV) spectroscopy measurements confirmed desorption in selected experiments. The amount of desorption was related to the type and concentration of electrolyte and the sequence of injecting the electrolyte solutions. Initial desorption upon exposure to solutions with high ionic strength was likely due to repulsion between negatively charged sites acquired at the silica and the asphaltenes. During the injection of low saline aqueous solutions, a critical expansion of the diffuse double layer was required for desorption to occur. Comparatively lower desorption of asphaltenes was observed in the CaCl2 solutions than in NaCl and seawater solutions. 相似文献
137.
We develop an exact method to calculate thermal Casimir forces between inclusions of arbitrary shapes and separation, embedded in a fluid membrane whose fluctuations are governed by the combined action of surface tension, bending modulus, and Gaussian rigidity. Each object's shape and mechanical properties enter only through a characteristic matrix, a static analog of the scattering matrix. We calculate the Casimir interaction between two elastic disks embedded in a membrane. In particular, we find that at short separations the interaction is strong and independent of surface tension. 相似文献
138.
Rukhshona Mavlyanova Rufeng Yang Tao Tao Md Aquib Samuel Kesse Mily Bazezy Joelle Maviah Kofi Oti Boakye‐Yiadom Muhammad Asim Farooq Bo Wang 《先进技术聚合物》2020,31(2):192-203
Hydrogels are cross‐linked three‐dimensional polymeric networks that play a vital role in solving the pharmacological and clinical limitations of the existing systems due to their unique physical properties such as affinity for biological fluids, tunable porous nature, high water content, ease of preparation, flexibility, and biocompatibility. Hydrogel also mimics the living natural tissue, which opens several opportunities for its use in biomedical areas. Injectable hydrogel allows temporal control and exceptional spatial arrangements and can offset hitches with established hydrogel‐based drug delivery systems. Here, we review the recent development of injectable hydrogels and their significance in the delivery of therapeutics such as cells, genes, and drug molecules and how these innovatory systems can complement the current delivery systems. 相似文献
139.
Daniel W. Armstrong Mohsen Talebi Nimisha Thakur M. Farooq Wahab Alexander V. Mikhonin Matt T. Muckle Justin L. Neill 《Angewandte Chemie (International ed. in English)》2020,59(1):192-196
We designed and demonstrated the unique abilities of the first gas chromatography–molecular rotational resonance spectrometer (GC‐MRR). While broadly and routinely applicable, its capabilities can exceed those of high‐resolution MS and NMR spectroscopy in terms of selectivity, resolution, and compound identification. A series of 24 isotopologues and isotopomers of five organic compounds are separated, identified, and quantified in a single run. Natural isotopic abundances of mixtures of compounds containing chlorine, bromine, and sulfur heteroatoms are easily determined. MRR detection provides the added high specificity for these selective gas‐phase separations. GC‐MRR is shown to be ideal for compound‐specific isotope analysis (CSIA). Different bacterial cultures and groundwater were shown to have contrasting isotopic selectivities for common organic compounds. The ease of such GC‐MRR measurements may initiate a new era in biosynthetic/degradation and geochemical isotopic compound studies. 相似文献
140.
Dr. Pushpak Mizar Aragorn Laverny Mohammad El‐Sherbini Dr. Umar Farid Dr. Michael Brown Florence Malmedy Prof. Dr. Thomas Wirth 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(32):9910-9913
Vicinal diamines constitute one the most important functional motif in organic chemistry because of its wide occurrence in a variety of biological and pharmaceutical molecules. We report an efficient metal‐free, highly stereoselective intramolecular diamination using a novel chiral hypervalent iodine reagent together with its application as an efficient catalyst for the synthesis of diamines. 相似文献