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外文期刊

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  • [期刊] Preparation of Co_3O_4@ZnO core-shell nanocomposites with intrinsic p-n junction as high-performance photoelectrodes for photoelectrochemical cathodic protection under visible light

    In this work, Co3O4@ZnO nanocomposite photoelectrodes with a core-shell structure were prepared, enabling enhanced photoelectrochemical activity under visible light illumination. This was demonstrated by the photoinduced cathodic polarization of 304 stainless steel in 3.5 wt% NaCl solution. The morphology, composition, crystalline structure and optical absorption properties of the photoelectrodes were characterized by various analysis techniques and UV-vis diffuse reflectance absorption spectroscopy. Results show that, compared to the ZnO nanorods, the Co3O4@ZnO nanocomposite photoelectrodes have a red shift of optical absorption and enhanced photoelectrochemical cathodic polarization on stainless steel under visible light. The enhanced photoelectrochemical performance is attributed to the narrow band gap of Co3O4 and the p-n junction formed at the Co3O4/ZnO interface. The Co3O4@ZnO nanocomposite photoelectrodes fabricated in this work achieve a photo-current density of 10.5 mu A/cm(2) and a cathodic polarization potential of - 720 mV (saturated calomel electrode) for 304 stainless steel in 3.5 wt% NaCl solution under visible light.

  • [期刊] Further hope for HYDROGEN

    Fuel cell buses currently operate in London (run by Transport for London) and Aberdeen (looked after by Stagecoach and First Group), having entered service as part of the EU's High V.Lo-City and HyTransit projects. At their peak, there were ten buses running in both locations, and the reactions from operators and passengers was positive, with no major issues being reported. In addition, the CHIC (Clean Hydrogen in European Cities) programme was hailed a success when it concluded back in 2016.

  • [期刊] Asymmetric Transfer Hydrogenation of α,β-Unsaturated Carbonyl Compounds to Saturated Alcohols as Catalyzed by Iridium Complexes of Tricyclic Bioxazoline-Fused Imidazole-Derived N-Heterocyclic Carbene Ligands

    A series of chiral iridium(I) (1-3)e complexes of bioxazoline fused imidazole derived N-heterocyclic carbene (NHC) ligands successfully carried out asymmetric transfer hydrogenation of a, β-unsaturated ketones in good to excellent yields (ca. 36-91%) and in low enantioselectivites (ca. 5-31% ee) at 1 mol% of the catalyst (1-3)e loading in the presence of NaOH as a base in i-PrOH at 75° C in 3 hours of reaction time. The iridium(I) (1-3)e complexes were synthesized directly from the bioxazoline fused imidazole derived NHC precursors namely {(3R,7R)-3,7-di- R-2,3,7,8-tetrahydrodioxazolo[3,2-c:3’,2’-e]imidazol-4-ium tri-fluoromethanesulfonate, R = s-butyl (1d), i-butyl (2d), i-propyl (3d)} by the treatment with {(COD)IrCl}2 (COD=1,5-cycloocta-diene) in presence of t-BuOK as a base at room temperature. The chiral bioxazoline fused imidazole NHC ligand precursors (1-3)d were synthesized from the commercially available optically pure amino acids by a sequence of reactions without requiring any chiral resolution.

  • [期刊] Investigating the mixed convection heat transfer of a nanofluid in a square chamber with a rotating blade

    Mixed convection heat transfer of water-alumina nanofluid in a square chamber with a rotating blade in its center is studied numerically. The governing equations are discretized by using a finite-difference method and solved simultaneously using the SIMPLE algorithm. The blade thickness is assumed to be negligible, the vertical walls of the chamber are at constant temperature of Tc and Th, and the horizontal walls are insulated. The effects of Rayleigh number (10(3) <= Ra <= 10(6)) and Richardson (0.1 <= Ri <= 100) number, the dimensionless length of the blade (0.6 <= a <= 0.8) and the volumetric percentage of nanoparticles (0 <= phi <= 0.03) on flow and thermal fields are investigated. The results show that an increase in Rayleigh number, volumetric percentage of nanofluid and blade length leads to heat transfer increasing in most cases, but an increase in Richardson number results in a reduction in heat transfer. It is revealed that the maximum blade rotation occurs at small Richardson numbers.

  • [期刊] Bacterial Growth and Death on Cotton Fabrics Conformally Coated with ZnO Thin Films of Varying Thicknesses via Atomic Layer Deposition (ALD)

    Hospital fabrics are commonly exposed to multiple patients and contaminated surfaces between washing/sterilization cycles. Consequently, these textiles act as vectors for the spread of diseases, especially bacterial pathogens. Many modification schemes have been proposed to mitigate the growth and spread of bacteria on fabrics, including use of antimicrobial metal oxide nanoparticles. The aim of this study is to examine the effectiveness of conformal nanoscale ZnO coatings applied to cotton fabrics via atomic layer deposition to control bacterial spread. We find that, at low ZnO loading fractions, bacteria metabolize Zn2+ ions and reproduce more rapidly. However, as the ZnO loading is increased, the higher concentrations of Zn2+ overwhelm the bacteria and the nanocoatings become effective antibacterial treatments, killing all bacteria present. These results map out an important design space for implementing ZnO coatings as a potential antimicrobial treatment for textiles and other surfaces.

  • [期刊] Evidence of weak ferromagnetic and antiferromagnetic interaction at low temperature in Pb(Fe2/3W1/3)o(3) multiferroic

    Disordered magnetoelectric Pb(Fe2/3W1/3)O-3 (PFW) was synthesized through columbite solid state reaction method in pure perovskite phase. Saturation magnetization of 0.013 mu(B)/f. u. was observed at 5 K, with a clear opening in the magnetic hysteresis loop around the origin. Temperature dependent magnetic susceptibility (chi) measurements revealed two different magnetic orderings, T-N1 similar to 350 K and another cusp, T-N2 below 20 K. The neutron diffraction studies were carried out at different temperatures to understand the existence of the controversial T-N2. The variation in the magnetic peak intensity clearly show that while decreasing temperature from 300 K to 2 K the intensity of the magnetic peak increases. This observation along with the observation of hysteresis loop at temperature below 20 K and the cusp in magnetic susceptibility data, confirms the existence of interaction between weak ferromagnetism and antiferromagnetism rather than spin-glassy nature or magnetic clusters.

  • [期刊] Radiation-Hardened 14T SRAM Bitcell With Speed and Power Optimized for Space Application

    In this paper, a novel radiation-hardened 14-transistor SRAM bitcell with speed and power optimized [radiation-hardened with speed and power optimized (RSP)-14T] for space application is proposed. By circuit-and layout-level optimization design in a 65-nm CMOS technology, the 3-D TCAD mixed-mode simulation results show that the novel structure is provided with increased resilience to single-event upset as well as single-event-multiple-node upsets due to the charge sharing among OFF-transistors. Moreover, the HSPICE simulation results show that the write speed and power consumption of the proposed RSP-14T are improved by similar to 65% and similar to 50%, respectively, compared with those of the radiation hardened design (RHD)-12T memory cell.

  • [期刊] Cystatin C serum levels in healthy children are related to age, gender, and pubertal stage

    BackgroundThis study aims to establish age- and gender-specific cystatin C (CysC) reference values for healthy infants, children, and adolescents and to relate them to pubertal stage, height, weight, and body mass index (BMI).MethodsSerum CysC and creatinine levels of 6217 fasting, morning venous blood samples from 2803 healthy participants of the LIFE Child study (age 3months to 18years) were analyzed by an immunoassay. Recruitment started in 2011; 1636 participants provided at least one follow-up measurement. Percentiles for CysC were calculated. Age- and gender-related effects of height, weight, BMI, and puberty status were assessed through linear regression models.ResultsOver the first 2years of life, median CysC levels decrease depending on height (ss=-0.010mg/l/cm, p<0.001) and weight (ss=-0.033mg/l/kg, p<0.001) from 1.06 to 0.88mg/l for males and from 1.04 to 0.87mg/l for females. Following the secondyear of age, the levels remain stable for eight years. From 11 to 14years of age, there is an increase of median CysC levels in males to 0.98mg/l and a decrease in females to 0.86mg/l. The change is associated with puberty (ss=0.105mg/l/Tanner stage, p<0.001 in males and ss=-0.093mg/l/Tanner stage, p<0.01 in females) and in males with height (ss=0.003mg/l/cm, p<0.001).ConclusionsCysC levels depend on age, gender, and height, especially during infancy and puberty. We recommend the use of age- and gender-specific reference values for CysC serum levels for estimating kidney function in clinical practice.

  • [期刊] Nutrient concentration in sediments accumulated in pre-treatment basins of urban LID technologies

    In this study, the contribution of pre-treatment basins of low impact development (LID) technologies to nutrient reduction performance was evaluated by understanding the distribution of nutrient in sediments accumulated in each system. The captured sediments were mostly silt to medium sand ranging from 9% to 92% of the sediments collected. Greater average N and P concentrations were found in silt particles amounting to 345 mg/kg and 696 mg/kg, respectively compared to sand and gravel. Although, N concentrations in accumulated sediments were found to be highly variable at different particle sizes (CV: 0.24 to 0.77) compared to P concentration (CV: 0.08 to 0.36) attributed to effective P treatment mechanism through deposition compared to complex nitrogen removal mechanisms. In addition, the difference between N and P concentrations of sediments collected in the pre-treatment basins of LID technologies and in-situ soil was attributed to the continuous pollutant input to the LID technologies during storm events. The study proved that pre-treatment basins of stormwater LID technologies reinforced the nutrient removal performances through sediment retention. The findings of this research may be used to design pre-treatment basins of LID technologies considering nutrients as a limiting factor.

  • [期刊] An adaptation reference-point-based multiobjective evolutionary algorithm

    It is well known that maintaining a good balance between convergence and diversity is crucial to the performance of multiobjective optimization algorithms (MOEAs). However, the Pareto front (PF) of multiobjective optimization problems (MOPs) affects the performance of MOEAs, especially reference point-based ones. This paper proposes a referencepoint-based adaptive method to study the PF of MOPs according to the candidate solutions of the population. In addition, the proportion and angle function presented selects elites during environmental selection. Compared with five state-of-the-art MOEAs, the proposed algorithm shows highly competitive effectiveness on MOPs with six complex characteristics. (C) 2019 Published by Elsevier Inc.

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