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Two-step synthesis of reduced graphene oxide with columnar-shaped ZnO composites and their photocatalytic performance with natural dye
摘要： Composites of ZnO with reduced graphene oxide were prepared in two-step synthesis process with constant temperature in variation with pH values. The synthesized composites were characterized and the results suggest that ZnO structure in the composites has a columnar morphology with an average diameter ranging 0.8–1.57 μm. The obtained properties of the composites with the present method confirmed that the material morphology influences the absorption and photocatalytic activity of natural dye under sunlight irradiation. The result shows that the maximum degradation efficiency is 64.40% achieved in 120 min.
关键词： Zinc oxide,Columnar morphology,Photocatalytic activity,Reduced graphene oxide,Natural dye
更新于2025-09-23 15:23:52
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CeO2/TiO2 nanostructures enhance adsorption and photocatalytic degradation of organic compounds in aqueous suspension
摘要： Mixed oxide interfaces are critical in the delivery of active components in photocatalytic processes. Cerium doped TiO2 photocatalysts were prepared using a hydrothermal route to manipulate the morphology of the photocatalyst and improve the interaction between CeO2 and TiO2 nanoparticles. These changes were compared with the photocatalytic activity and adsorption capacity of the solids. The photocatalysts were used to degrade polyvinylpyrrolidone (PVP) and methylene blue (MB) as test compounds. A low photodegradation rate of PVP (0.0001 min?1 and 0.0005 min?1 under visible and UV light, respectively) was observed using Ce-doped photocatalysts, with no adsorption. The high adsorption capacity of MB (34.46 mg g?1) proved that the local morphology of the nanostructured CeO2/TiO2 photocatalysts is more important than the amount of CeO2 in the sample, and the main role of the CeO2 on mixed photocatalysts is to improve thermal stability during the synthesis. XRD, XPS, BET surface area, UV–vis and TEM techniques confirmed this conclusion. The rate of degradation of MB by the Ce-doped photocatalyst decreased dramatically when using the singlet oxygen scavenger L-Histidine (0.0214 min?1 to 0.0001 min?1), indicating a photocatalysis sensitized by the dye, under visible and UV light.
关键词： Cerium,Photosensitization,Reactive oxygen species,Adsorption,Morphology
更新于2025-09-23 15:23:52
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Nanosheet and nanosphere morphology dominated photocatalytic & antibacterial properties of ZnO nanostructures
摘要： To address the issue of water contamination with the usage of dyes and undesired bacterial growth on food products, different ZnO nanostructures have been studied in present manuscript. XRD technique has investigated the crystal purity of ZnO nanostructures. The alteration in chemical structural parameters (bond vibration and spring constant etc.) confirms their structure level modification by fourier transform infrared spectroscopy (FTIR). The maximum efficiency of methylene blue dye degradation has been observed in nanosheet (～96.42%) as compared to nanosphere (～95.45%) & nanorod (～87.12%) morphology. In addition, the antibacterial activity of ZnO nanospheres for E. coli and S. aureus bacteria shows inhibition diameter of 10 mm & 12 mm is credited due to generation of active oxidizing agents as compared to other reported morphologies. Present studied ZnO nanomaterials embolden researchers to investigate the unexplored aspects of ZnO nanomaterials to ameliorated efficiency in photocatalytic and antibacterial applications.
关键词： Morphology,Antibacterial,Nanostructures,Photocatalytic
更新于2025-09-23 15:23:52
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Comparative solvent quality dependent crystallization in solvent vapor annealing of P3HT:PCBM thin films by in-situ GIWAXS
摘要： We present a novel in-depth study correlating multiple solvent properties (boiling point, vapor pressure, and solubilities of P3HT and PCBM) on P3HT and PCBM crystal growth kinetics in blend thin films via in-situ GIWAXS in conjunction with multiple substrate energies. Solvent vapor annealed (SVA) P3HT:PCBM films in a closed chamber, saturated with different solvents (o-dichlorobenzene (DCB), o-xylene, tetrahydrothiophene (THT), toluene, benzene, tetrahydrofuran (THF), and carbon disulfide (CS2)) were studied in real time. We observed that structure growth and dissolution kinetics of the both P3HT and PCBM crystals largely depend on physical properties of solvent and relative solubilities of P3HT and PCBM. The film morphology of the annealed films resulted in PCBM enrichment and occasional crystallization occurred at the solvent vapor saturated air interfaces. We observed strikingly different PCBM crystallization upon annealing of the films when cast from THF resulting in highly ordered PCBM crystals at the film surface. THF has high vapor pressure and relatively low solubilities for both P3HT and PCBM. At the other extreme CS2 produced the lowest crystallinity due to its very high vapor pressure such that the solvent evaporates before significant crystallization can occur. We characterized all the annealed samples using AFM, UV-Vis spectroscopy, and XPS. AFM probed topographic structures with coarsening of both the P3HT and PCBM domains at air surface by solvent annealing. We observe via UV-vis spectroscopy that, in general, intrachain electronic delocalization and interchain electron transitional jump due to π-π stacking increases in the post SVA films. This indicates that the chains are better organized with increased conjugation lengths. SVA has a substantial effect on P3HT monomer to PCBM ratio as determined by XPS at the polymer-air interface. In all cases, relative to the P3HT monomer:PCBM ratio of as-cast films from DCB, the air surfaces became more enriched by PCBM with SVA.
关键词： P3HT,GIWAXS,Morphology
更新于2025-09-23 15:23:52
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Automatic fracture–vug identification and extraction from electric imaging logging data based on path morphology
摘要： We present a path morphology method to separate total rock pore space into matrix, fractures and vugs and derive their pore structure spectrum. Thus, we can achieve fine pore evaluation in fracture–vug reservoirs based on electric imaging logging data. We automatically identify and extract fracture–vug information from the electric imaging images by adopting a path morphological operator that remains flexible enough to fit rectilinear and slightly curved structures because they are independent of the structuring element shape. The Otsu method was used to extract fracture–vug information from the background noise caused by the matrix. To accommodate the differences in scale and form of the different target regions, including fracture and vug path, operators with different lengths were selected for their recognition and extraction at the corresponding scale. Polynomial and elliptic functions are used to fit the extracted fractures and vugs, respectively, and the fracture–vug parameters are deduced from the fitted edge. Finally, test examples of numerical simulation data and several measured well data have been provided for the verification of the effectiveness and adaptability of the path morphology method in the application of electric imaging logging data processing. This also provides algorithm support for the fine evaluation of fracture–vug reservoirs.
关键词： Path morphology,Electric imaging logging,Fracture–vug reservoir,Image automatic identification
更新于2025-09-23 15:23:52
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High throughput MOVPE and accelerated growth rate of GaAs for PV application
摘要： We present the feasibility of metalorganic vapor phase epitaxy (MOVPE) with extremely high-speed growth of GaAs for solar cell applications. The growth rate was increased up to 120 μm/h, and exhibited an almost linear relationship with the amount of supplied trimethylgallium (TMGa). The thickness variation and doped carrier concentration of GaAs grown at 90 μm/h were comparable to those of conventionally grown GaAs at a lower growth rate. The potential for reducing the V/III supply ratio was investigated to reduce the material cost. Non-doped GaAs wafers were grown at the accelerated growth rate of 90 μm/h, with various V/III ratios. The growth rate of GaAs increased by 20% when the V/III ratio was decreased from 40 to 5. In low temperature photo-luminescence (PL) measurement, significant change in PL spectra was not observed, indicating that there was no significant change in quality. The light-power conversion efficiency was almost comparable for V/III ratios from 10 to 40 whereas that at the lowest V/III ratio of 5 was degraded. Photovoltaic (PV) solar cells of GaAs were fabricated with various growth condition. It is found that the performance of the cells grown at 90 μm/h were comparable with previous results.
关键词： A3. Metalorganic vapor phase epitaxy,B2. Semiconducting GaAs,B3. Solar cells,A1. Crystal morphology
更新于2025-09-23 15:23:52
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A novel parameter derived from photoplethysmographic pulse wave to distinguish preeclampsia from non-preeclampsia
摘要： Objective: To describe the comparative hierarchical area ratio (CHAR), a novel parameter derived from the photoplethysmographic (PPG) pulse wave and differences in CHAR values in parturients with and without preeclampsia (PE). Methods: A total of 59 parturients (37 without and 22 with PE) was conducted at the Women’s Hospital of Zhejiang University in Hangzhou, China. We calculated the CHAR values derived from the PPG pulse wave and compared them in parturients with and without PE. Result: The values of CHAR derived from the parturients with PE were lower compared to those without PE (p<0.01). The ROC analysis indicated that the best threshold for the mean value of CHAR was 7.92 to predict PE with a sensitivity of 86.4% and a specificity of 87.1%, while the threshold for the standard deviation of CHAR was 0.76 with a sensitivity of 77.3% and a specificity of 77.4%. The area under the curve (AUC) was 0.91 for mean value of CHAR while 0.78 for standard deviation of CHAR. Meanwhile, a contrast of AUC between CHAR and the former parameter we proposed showed CHAR had better performance in distinguishing PE (0.908 over 0.615, p<0.01). Conclusion: The novel parameter, CHAR, derived from PPG pulse wave differs in parturients with and without PE with high sensitivity and specificity, suggesting that the CHAR might be an effective tool in differentiating the presence of PE.
关键词： Morphology,Characteristics Extraction,Comparative Hierarchical Area Ratio (CHAR),Photoplethysmographic pulse wave,Preeclampsia
更新于2025-09-23 15:23:52
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Scandium Molybdate Microstructures with Tunable Phase and Morphology: Microwave Synthesis, Theoretical Calculations, and Photoluminescence Properties
摘要： In this paper, scandium molybdate microstructures have been prepared from solution via a microwave heating method. By controlling the experimental parameters such as molar ratio of reagent and reaction time, scandium molybdates with tunable phase and diverse morphologies including snowflakes, microflowers, microsheets, and branched spindles were obtained. The density of states and surface energies of Sc2Mo3O12 were primarily studied from first-principles calculations. An indirect band gap of 3.56 eV was observed for crystalline Sc2Mo3O12, and the surface energies of various facets were determined to be 0.27–0.91 J/m2. The influence of n(Sc3+):n(Mo7O24 6?) (short for Sc/Mo) molar ratio was systematically investigated and well-characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and UV–vis absorption spectroscopy (UV–vis). Results indicate that the Sc/Mo molar ratio has a great effect on the phase and morphology. Diffuse reflection spectra (DRS) revealed the Egap can be readily tuned from 3.69 to 4.16 eV, which is in accordance with the theoretical result. The photoluminescence (PL) properties of Eu3+-doped Sc2Mo3O12 were discussed. This facile synthesis strategy could be extended to the synthesis of other molybdates.
关键词： photoluminescence,morphology control,microwave synthesis,scandium molybdate,density functional theory
更新于2025-09-23 15:23:52
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Unusual Nano-Microcrystals of Natural Diamond
摘要： Described are unusual nano-microcrystals of natural diamond found in a meteorite crater of Ukraine and advised about the earlier unknown mechanism of diamond polyhedra growth—the formation by globules. It was revealed that diamond nano-microcrystals in a meteorite crater are very similar to globular crystals, and at the same time have octahedral faceting. The morphology and composition of diamond nano-microcrystals are studied by scanning electron microscopy and with an energy dispersive X-ray analyser. These tiny crystals are grown on the grains of impact apographitic diamond from the Bilylivka meteorite crater (Zapadnaya impact crater) on the Ukrainian Shield. Their surface morphology indicates that the nano-microdiamonds are grown, most probably, by a vapor deposition process immediately after the formation of the impact diamond–transformation of the graphite into diamond and lonsdaleite.
关键词： globular polyhedra,growth of crystals,the Ukrainian Shield,nano-microdiamond,natural impact apographitic diamond,morphology,Bilylivka meteorite crater
更新于2025-09-23 15:23:52
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Reversed Crystal Growth
摘要： In the last decade, a reversed growth route has been found in many crystal growth processes. In these systems, a single crystal does not develop from a single nucleus. The precursor molecules/ions or nanocrystallites aggregate into some large amorphous or polycrystalline particles. Multiple-nucleation on the surface of the amorphous particles or surface re-crystallization of the polycrystalline particles then takes place, forming a single crystal shell with a regular morphology. Finally, the crystallization extends from the surface to the core to form single crystals. This non-classical crystal growth route often results in some special morphologies, such as core-shell structures, hollow single crystals, sandwich structures, etc. This article gives a brief review of the research into reversed crystal growth and demonstrates that investigation of detailed mechanisms of crystal growth enables us to better understand the formation of many novel morphologies of the crystals. Some unsolved problems are also discussed.
关键词： nucleation,crystal growth,core-shell structure,crystal morphology,hollow crystal,electron microscopy
更新于2025-09-23 15:23:52