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In this paper, a totally asymmetric simple exclusion process (TASEP) extended model has been used to study the defect sites on symmetric coupling two-channel boundaries. Two classic cases were discussed, defined as Case A, the defect sites on the left boundaries, and Case B, the defect sites on the right boundaries. Through the theory calculation, for symmetric coupling two-lane TASEP with arbitrary hopping rate, the existence conditions of different phases and the property of the system can be obtained. Based on these outcomes, the effects of defect sites on phase evaluation, system density, and currents have been investigated by theoretical and simulative methods. The result indicates that the existing conditions of the maximal current phase depend on the hopping rate of the defect sites. The results from Monte Carlo simulations are in good agreement with that from theoretical calculations. [ABSTRACT FROM AUTHOR]

Quadrangular-pyramid-octahedral CeO2 with defects was successfully prepared and first used as effective and reusable heterogeneous catalyst for photo- and thermal- synergistic catalytic synthesis of DMC, and it showed better catalytic performance than that of thermocatalysis alone. The corner defects may be the active site based on experimental result and DFT calculation. The CeO2 with specific defects was prepared by PECVD method and first applied for photo-thermal synergistic catalytic synthesis of DMC from CO2 and methanol, which showed superior catalytic performance to that of thermocatalysis alone, and the active site maybe the corner defect. [ABSTRACT FROM AUTHOR]

Carbon nanospikes (CNSs) are a new nanomaterial that has enhanced surface roughness and surface oxide concentration, increasing the sensitivity for dopamine detection. However, CNS-modified electrodes (CNSMEs) have not been characterized for other neurochemicals, particularly those with higher oxidation potentials. The purpose of this study was to evaluate CNSMEs for the detection of adenosine, hydrogen peroxide (H2O2), and histamine. The sensitivity increased with CNSs, and signals at CNSMEs were about 3.3 times higher than CFMEs. Normalizing for surface area differences using background currents, CNSMEs show an increased signal of 4.8 times for adenosine, 1.5 times for H2O2, and 2 times for histamine. CNSMEs promoted the formation of secondary products for adenosine and histamine, which enables differentiation from other analytes with similar oxidation potentials. CNSs also selectively enhance the sensitivity for adenosine and histamine compared to H2O2. A scan rate test reveals that adenosine is more adsorption-controlled at CNS electrodes than CFMEs. CNSMEs are antifouling for histamine, with less fouling because the polymers formed after histamine electrooxidation do not adsorb due to an elevated number of edge planes. CNSMEs were useful for detecting each analyte applied in brain slices. Because of the hydrophilic surface compared to CFMEs, CNSMEs also have reduced biofouling when used in tissue. Therefore, CNSMEs are useful for tissue measurements of adenosine, hydrogen peroxide, and histamine with high selectivity and low fouling. [ABSTRACT FROM AUTHOR]

How to directionally design the hollow zeolite via a green route is of great significance. Here, we successfully synthesized the hollow Fe-silicate-1 encapsulated ultra-small Fe2O3 nanoparticles (2.5 nm) with higher yield (85.2%) by mother liquid than traditional dissolution-recrystallization for the first time, which was achieved by precisely regulating the number and distribution of defects in zeolite and cleverly utilizing the TPAOH and nuclei in mother liquor. The effects of synthetic temperature, synthetic period and addition amount of parent zeolite on the formation of hollow zeolite have been investigated and the effect of synthetic conditions on the defects in parent zeolite has been also firstly quantified. The corresponding formation mechanism has been proposed. The abundant inner defects provided by the zeolite synthesized at 130 °C for 1 day and large amount of TPAOH remaining in mother liquid are conducive to the formation of hollow zeolite. Meanwhile, both parent zeolite and nuclei (4-, 5-member rings and structure units) in mother liquid obtained at 130 °C play the crucial roles in enhancing the zeolite yield. Notably, Fe2O3 nanoparticles could decompose into small fragments by the interaction with nuclei in mother liquid. Partial ultra-small Fe2O3 nanoparticles would be encapsulated in cavity and the rest could be inserted in the zeolite framework, which is significantly different from the conventional dissolution-recrystallization mechanism. The obtained encapsulated catalyst shows the superior catalytic performance and stability in phenol and tetracycline degradation reactions. [ABSTRACT FROM AUTHOR]

Pd-Ir mesocrystals with rough surface and highly branched structure were synthesized through a facile co-reduction method. The morphology evolution shows the mesocrystals were formed by oriented attachment of nanoparticles, and abundant defects sites as well as synergetic effect between building units were formed during mesocrystals oriented attachment process. Therefore, the supported Pd-Ir mesocrystals show a significant enhancement in catalytic performance in hydrogenation of 2-ethylanthraquinone compared with conventional Pd-Ir nanoparticles. The high activity can be ascribed to high densities of defect sites in Pd-Ir MCs catalyst, which facilitated H activation. In addition, the geometric effect of Pd-Ir MCs catalyst was responsible for inhibiting further hydrogenation of eAQH to undesired consecutive byproducts. Graphical Abstract: [ABSTRACT FROM AUTHOR]

We examined solution-processed alkaline-earth-metal doped gallium indium oxide (GIO) thin film transistors (TFT) and studied the relationship between the dopant species and the threshold voltage (V) stability. As the atomic number of the dopant increases, the amount of oxygen vacancies, which act as the major defect sites, decreased and the V stability is enhanced. The electron trapping times and total defect sites were quantitatively calculated. Particularly, Sr-doped GIO TFT show the highest V stability under positive gate bias and the origin of V stability enhancement is deduced by using the partial charge model and reaction kinetics. [ABSTRACT FROM AUTHOR]

Optical absorption as well as thermoluminescence emission of LiF:Mg single crystals have been measured before and after exposed to gamma radiation from Co-60 source. Result of DFT calculations for pure bulk LiF indicates a large reduction in band gap energy of the crystal after doping with Mg ions. As impurity concentration of Mg ions in LiF is increased, the activation energy of 225 and 313 nm trap centers increases linearly with almost same slope. However, the activation energy of trap centers absorbing at 250 nm remains nearly unchanged as doping concentration increased, indicating that these trap sites are independent of Mg ions. Values of average experimental activation energy ( E) for trap centers absorbing at 250, 225 and 313 nm for temperature range of 300-573 K have been obtained as 0.33 ± 0.030, 0.21 ± 0.012 and 0.16 ± 0.013 eV, respectively. [ABSTRACT FROM AUTHOR]

A detailed discussion of the photochemistry of TiO2 surfaces is presented, covering important work from the literature as well as more recent studies. The production and characterization of surface defects is discussed, and studies of the adsorption of molecular oxygen on these defects is presented. In addition, both chemical and physical methods for detection and measurement of defect sites on TiO2 are reviewed. The role of nitrogen doping on shifting the photothreshold energy of TiO2 is discussed and the active chemical state of the nitrogen is described, based on XPS N(1s) binding energies. Observations of charge transfer between excited TiO2 and adsorbates are presented, and it is shown that the electronegativity of the attachment atom which forms the surface bond is important in governing charge transfer [ABSTRACT FROM AUTHOR]