358 research outputs found

    Facile Preparation and Photoinduced Superhydrophilicity of Highly Ordered Sodium-Free Titanate Nanotube Films by Electrophoretic Deposition

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    Highly ordered sodium-free titanate nanotube films were one-step prepared on F-doped SnO2-coated (FTO) glass via an electrophoretic deposition method by using sodium titanate nanotubes as the precursor. It was found that the self-assembled formation of highly ordered sodium titanate nanotube films was accompanied with the effective removal of sodium ions in the nanotubes during the electrophoretic deposition process, resulting in the final formation of protonated titanate nanotube film. With increasing calcination temperature, the amorphous TiO2 phase is formed by a dehydration process of the protonated titanate nanotubes at 300°C and further transforms into anatase TiO2 when the calcination temperature is higher than 400°C. Compared with the as-prepared titanate nanotube film, the calcined titanate nanotube film (300–600°C) exhibits attractive photoinduced superhydrophilicity under UV-light irradiation. In particular, 500°C-calcined films show the best photoinduced superhydrophilicity, probably due to synergetic effects of enhanced crystallization, surface roughness, and ordered structures of the films

    Breast cancer metastasis to thyroid: a retrospective analysis

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    Background: Breast cancers metastasizing to thyroid gland are relatively uncommon in clinical practice.Objective: Retrospective analysis of data from breast cancer patients with thyroid metastasis (TM).Methods: The US suspected, fine-needle aspiration cytology (FNAC) confirmed TM in breast cancer patients, treated between 2005 and 2015 at our hospital, was retrospectively analyzed. The data were re-evaluated by the pathologist and radiologist who were blinded to the patients’ data.Results: FNAC and immunohistochemistry confirmed the ultrasonography (US) suspected TM in eight breast cancer patients. Clinically both unilateral and bilateral TM was seen, which were symptomless and metachronously (6-121 months) metastasized. Six of eight cases exhibited recurrence/distant metastasis and were treated with chemotherapy/ thyroidectomy of which two cases passed away. The remaining two patients had no recurrences/distant metastases and were treated with partial/total thyroidectomy. Post-chemotherapy US showed more homogenous thyroid parenchyma with gathering of calcification that reduced in size, revealing the sensitiveness of TM to chemotherapy.Conclusion: US was useful in screening TM in breast cancer patients. Both partial and total thyroidectomy was effective in disease free survival of isolated TM cases, with controlled primary condition. TM responded well to chemotherapy in most of the recurrent breast cancer cases with or without distant metastasis.Keywords: Thyroid, ultrasonography, breast cancer, metastasis

    Casing Pipe Damage Detection with Optical Fiber Sensors: A Case Study in Oil Well Constructions

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    Casing pipes in oil well constructions may suddenly buckle inward as their inside and outside hydrostatic pressure difference increases. For the safety of construction workers and the steady development of oil industries, it is critically important to measure the stress state of a casing pipe. This study develops a rugged, real-time monitoring, and warning system that combines the distributed Brillouin Scattering Time Domain Reflectometry (BOTDR) and the discrete fiber Bragg grating (FBG) measurement. The BOTDR optical fiber sensors were embedded with no optical fiber splice joints in a fiber-reinforced polymer (FRP) rebar and the FBG sensors were wrapped in epoxy resins and glass clothes, both installed during the segmental construction of casing pipes. In situ tests indicate that the proposed sensing system and installation technique can survive the downhole driving process of casing pipes, withstand a harsh service environment, and remain intact with the casing pipes for compatible strain measurements. The relative error of the measured strains between the distributed and discrete sensors is less than 12%. The FBG sensors successfully measured the maximum horizontal principal stress with a relative error of 6.7% in comparison with a cross multipole array acoustic instrument

    The impact of atmospheric N deposition and N fertilizer type on soil nitric oxide and nitrous oxide fluxes from agricultural and forest Eutric Regosols

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    Agricultural and forest soils with low organic C content and high alkalinity were studied over 17 days to investigate the potential response of the atmospheric pollutant nitric oxide (NO) and the greenhouse gas nitrous oxide (N2O) on (1) increased N deposition rates to forest soil; (2) different fertilizer types to agricultural soil and (3) a simulated rain event to forest and agricultural soils. Cumulative forest soil NO emissions (148–350 ng NO-N g−1) were ~ 4 times larger than N2O emissions (37–69 ng N2O-N g−1). Contrary, agricultural soil NO emissions (21–376 ng NO-N g−1) were ~ 16 times smaller than N2O emissions (45–8491 ng N2O-N g−1). Increasing N deposition rates 10 fold to 30 kg N ha−1 yr−1, doubled soil NO emissions and NO3− concentrations. As such high N deposition rates are not atypical in China, more attention should be paid on forest soil NO research. Comparing the fertilizers urea, ammonium nitrate, and urea coated with the urease inhibitor ‘Agrotain®,’ demonstrated that the inhibitor significantly reduced NO and N2O emissions. This is an unintended, not well-known benefit, because the primary function of Agrotain® is to reduce emissions of the atmospheric pollutant ammonia. Simulating a climate change event, a large rainfall after drought, increased soil NO and N2O emissions from both agricultural and forest soils. Such pulses of emissions can contribute significantly to annual NO and N2O emissions, but currently do not receive adequate attention amongst the measurement and modeling communities

    Regression modeling based on improved genetic algorithm

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    Regresijski model je dobro uhodana metoda u analizi podataka s primjenom u raznim područjima. Izbor nezavisnih varijabli i matematički transformiranih u regresijski model, često predstavlja izazovan problem. Nedavno je nekoliko znanstvenika primijenilo evolucijski proračun za rješenje tog problema, ali rezultat nije učinkovit onoliko koliko smo željeli. Ukrižena (crossover) operacija u GA redizajnirana je primjenom Latin hypercube uzorkovanja, a zatim, kombinacijom dvaju uobičajeno korištenih statističkih kriterija (AIC, BIC), dajemo poboljšani genetički algoritam za rješavanje problema izbora statističkog modela. Predloženim se algoritmom može prevladati jaka ovisnost o putanji i osloniti na iskustvo stečeno primjenom klasičnih pristupa. Usporedba rezultata simulacije u rješavanju problema odabira statističkog modela s ovim poboljšanim GA, tradicionalnog genetičkog algoritma i klasičnog algoritma za odabir modela pokazuje da je novi GA superiorniji u rješavanju kvalitete, brzine konvergencije i drugih različitih pokazatelja.Regression model is a well-established method in data analysis with applications in various fields. The selection of independent variables and mathematically transformed in a regression model is often a challenging problem. Recently, some scholars have used evolutionary computation to solve this problem, but the result is not effective as we desired. The crossover operation in GA is redesigned by using Latin hypercube sampling, then combining two commonly used statistical criteria (AIC, BIC) we are presenting an improved genetic algorithm based for solving statistical model selection problem. The proposed algorithm can overcome strong path-dependence and rely on experience of classical approaches. Comparison of simulation results in solving statistical model selection problem with this improved GA, traditional genetic algorithm and classical algorithm for model selection show that the new GA has superiority in solution of quality, convergence rate and other various indices

    Unconventional polarization switching mechanism in (Hf, Zr)O2 ferroelectrics

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    HfO2_{2}-based ferroelectric thin films are promising for their application in ferroelectric devices. Predicting the ultimate magnitude of polarization and understanding its switching mechanism are critical to realize the optimal performance of these devices. Here, a generalized solid-state variable cell nudged elastic band (VCNEB) method is employed to predict the switching pathway associated with domain-wall motion in (Hf, Zr)O2_{2} ferroelectrics. It is found that the polarization reversal pathway, where three-fold coordinated O atoms pass across the nominal unit-cell boundaries defined by the Hf/Zr atomic planes, is energetically more favorable than the conventional pathway where the O atoms do not pass through these planes. This finding implies that the polarization orientation in the orthorhombic Pca21_{1} phase of HfO2_{2} nd its derivatives is opposite to that normally assumed, predicts the spontaneous polarization magnitude of about 70 μ{\mu}C/cm2^{2} that is nearly 50% larger than the commonly accepted value, signifies a positive intrinsic longitudinal piezoelectric coefficient, and suggests growth of ferroelectric domains, in response to an applied electric field, structurally reversed to those usually anticipated. These results provide important insights into the understanding of ferroelectricity in HfO2_{2}-based ferroelectrics.Comment: 34 pages, 28 figure

    Recent updates on electrochemical degradation of bio-refractory organic pollutants using BDD anode: a mini review

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    Boron-doped diamond (BDD) is playing an important role in environmental electrochemistry and has been successfully applied to the degradation of various bio-refractory organic pollutants. However, the review concerning recent progress in this research area is still very limited. This mini-review updated recent advances on the removal of three kinds of bio-refractory wastewaters including pharmaceuticals, pesticides, and dyes using BDD electrode. It summarized the important parameters in three electrochemical oxidation processes, i.e., anodic oxidation (AO), electro-Fenton (EF), and photoelectro-Fenton (PEF) and compared their different degradation mechanisms and behaviors. As an attractive improvement of PEF, solar photoelectro-Fenton using sunlight as UV/vis source presented cost-effectiveness, in which the energy consumption for enrofloxacin removal was 0.246 kWh/(g TOC), which was much lower than that of 0.743 and 0.467 kWh/(g TOC) by AO and EF under similar conditions. Finally the existing problems and future prospects in research were suggested
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