Results 1 - 10 of 103
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[en] This paper focuses on the preparation of boron doped ZnO (ZnO:B) films prepared by nonreactive mid-frequency magnetron sputtering from ceramic target with 2 wt.% doping source. Adjusting power density, ZnO:B film with low resistivity (1.54 × 10−3 Ω cm) and high transparency (average transparency from 400 to 1100 nm over 85%) was obtained. Different deposition conditions were introduced as substrate fixed in the target center and hydrogen mediation. Hall mobility increased from 11 to above 26 cm2/V·s, while carrier concentration maintained almost the same, leading to low resistivity of 6.45 × 10−4 Ω cm. Transmission spectra of ZnO:B films grown at various growth conditions were determined using a UV–visible-NIR spectrophotometer. An obvious blue-shift of absorption edge was obtained while transmittances between 600 nm and 1100 nm remained almost the same. Optical band baps extracted from transmission spectra showed irregular enhancement due to the Burstein–Moss effect and band gap renormalization. Photoluminescence spectra also showed a gradual increase at UV emission peak due to free exciton transition near band gap. We contributed this enhancement in both optical band gap and UV photoluminescence emission to the lattice structure quality melioration. - Highlights: ► Boron doped ZnO films have been prepared by magnetron sputtering. ► Different deposition conditions are introduced to make properties melioration. ► Hall mobility increases by using static deposition mode and hydrogen mediation. ► Optical band gap increases with static mode and hydrogen mediation. ► Lattice structure quality melioration is assumed to explain this improvement.
[en] Graphical abstract: -- Highlights: •PPY-GO-BiCoPc composite was formed using a simple electrochemical method for the first time. •A novel PoPD-MIP sensor based on PPY-GO-BiCoPc composite had been fabricated. •The PPY-GO-BiCoPc functional composite was introduced to improve performance of the sensor. •Highly sensitive, selective and stable sensor had been achieved. •The established MIP sensor could be promising in food safety analysis. -- Abstract: A facile and efficient molecularly imprinted polymer (MIP) recognition element of electrochemical sensor was fabricated by directly electro-polymerizing monomer o-phenylenediamine (oPD) in the presence of template quinoxaline-2-carboxylic acid (QCA), based on one-step controllable electrochemical modification of poly(pyrrole)-graphene oxide-binuclear phthalocyanine cobalt (II) sulphonate (PPY-GO-BiCoPc) functional composite on glassy carbon electrode (GCE). The MIP film coated on PPY-GO-BiCoPc functional composite decorated GCE (MIP/PPY-GO-BiCoPc/GCE) was presented for the first time. The synergistic effect and electro-catalytic activity toward QCA redox of PPY-GO-BiCoPc functional composite were discussed using various contrast tests. Also, the effect of experimental variables on the current response such as, electro-polymerization cycles, template/monomer ratio, elution condition for template removal, pH of the supporting electrolyte and accumulation time, were investigated in detail. Under the optimized conditions, the proposed MIP sensor possessed a fast rebinding dynamics and an excellent recognition capacity to QCA, while the anodic current response of square wave voltammetry (SWV) was well-proportional to the concentration of QCA in the range of 1.0 × 10−8–1.0 × 10−4 and 1.0 × 10−4–5.0 × 10−4 mol L−1 with a low detection limit of 2.1 nmol L−1. The established sensor was applied successfully to determine QCA in commercial pork and chicken muscle samples with acceptable recoveries (91.6–98.2%) and satisfactory precision (1.9–3.5% of SD), demonstrating a promising feature for applying the MIP sensor to the measurement of QCA in real samples
[en] Graphical abstract: The incorporation of La"3"+ ions in KTaO_3 host lattice led to a monotonous lattice contraction and particle size reduction, showing an excellent photocatalytic performance. - Highlights: • La"3"+ incorporation in KTaO_3 led to a lattice contraction, particle size reduction. • Oxidative capacity of the photo-excited carriers increases after La"3"+ ions doping. • Ta"4"+ appearance was helpful for the separation of electron-hole pairs. • Photocatalytic performance of K_1_−_xLa_xTaO_3 optimized by La"3"+ doping. - Abstract: La"3"+-doped cubic potassium tantalate photocatalysts were prepared by a hydrothermal treatment process. It is found that the La"3"+ ions were homogeneously incorporated in the KTaO_3 host lattice, leading to a monotonous lattice contraction and particle size reduction. Meanwhile, the BET surface areas were also enlarged from 4.9 to ∼9.8 m"2 g"−"1. Consistently, La"3"+-doped KTaO_3 nanocrystals showed a broadened band gap, which can be well-defined as a consequence of the contractive particle size. DFT calculation predicted a deeper band edge and a dispersive dense state of valance state by La"3"+ ions doping due to the hybridization of O 2p and La 6p orbitals, increasing the oxidative capacity and mobility of photogenerated charge carriers, thus enhance the photocatalytic activity. The mixed state of Ta"5"+ and Ta"4"+ was found to appear in the K_1_−_xLa_xTaO_3 nanocrystals, which may suppress the formation of cationic vacancies. The superior photocatalytic performance of K_1_−_xLa_xTaO_3 nanocrystals was achieved by well-controlled contractive particle size and optimized La"3"+ doping level
[en] An orthogonal field experiment of giant reed (Arundo donax) modified with organic complex fertiliser (OCF), and OCF and fly ash (O&F), at different planting densities was carried out in metal-contaminated soil. The available percentage of arsenic (As) and lead (Pb) in soil decreased from 8.45% to 2.19% and from 29.6% to 13.5% by OCF, respectively, and that of cadmium (Cd) was reduced from 25.3% to 6.49% by O&F. The total biomass of giant reed was 631 g per individual following application of O&F in contaminated soil. The accumulation of As, Cd, and Pb in giant reed was 1.57, 4.06, and 11.25 mg per individual. Urease and sucrase activity were 87.4 NH4-N μg/g d and 63.1 glucose mg/g d in response to the treatments modified using OCF, while the highest dehydrogenase activity was 101 TPF (triphenyltetrazolium formazan) μg/g d in the treatments modified using O&F. Dominant bacteria (frequency > 50%) were enriched with increasing planting density of giant reed. These results indicate that the phytostabilisation of metal-contaminated soil by giant reed could be improved by the application of O&F or OCF. - Highlights: • Both OCF and O&F increased biomass of giant reed and decreased available content of As, Cd and Pb in soil. • Dominant bacteria communities were enriched with increased planting density of giant reed in contaminated soil. • DHA was a reliable indicator of soil eco-environmental quality in phytoremediation with giant reed.
[en] Objective: To explore the character of the regional cerebral blood flow (rCBF) of heroin addicts during the exposure to the heroin-related cues. Methods: Twenty-five heroin dependent individuals undergoing detoxification for more than one month were enrolled in the present study. All subjects were exposed to the heroin-related cues for 15 min. The rCBF was measured in these patients before and after exposure to heroin-related cues. Result: The rCBF in the frontal, temporal cortex and amygdala was significantly increased during the exposure to heroin-related cues. Conclusion: The findings indicate that drug-related cues play a critical role in the relapse of drug dependence; and the frontal, temporal cortex and amygdala are involved in the relapsing process
[en] A two-stage monolithic microwave integrated circuit (MMIC) low noise amplifier (LNA) fabricated in 0.5 μm GaAs pHEMT is presented. The Miller effect introduced by the parasitic gate–drain capacitance is utilized to decrease the value of the input inductor. Additionally, the input on-chip inductor is a novel high Q gradual structure. The noise figure is reduced with these two methods. With good input and output matching, the LNA achieves a noise figure of 0.75 dB and a small signal gain of 32.7 dB over 698–806 MHz. The input 1 dB compression point is −21.8 dBm and the input third order interception point is −10 dBm. (paper)
[en] Surface nanobubbles emerging at solid–liquid interfaces show extreme stability. In this paper, the stability of surface nanobubbles in degassed water is discussed and investigated by AFM. The result demonstrates that surface nanobubbles are kinetically stable and the liquid/gas interface is gas impermeable. The force modulation experiment further proves that there is a layer coating on nanobubbles. These critical properties suggest that surface nanobubbles may be stabilized by a layer which has a great diffusive resistance. (paper)
[en] Background: It has already been confirmed that the SCRIT (Self-Confining Radioactive Isotope Ion Target) method can be used for electron scattering experiment for short-lived nuclei. An electron scattering facility consisting of a microtron type electron accelerator (RTM: Racetrack Microtron), an electron storage ring (SR2: SCRIT-equipped RIKEN Storage Ring) and an ISOL (Isotope Separator Online) involving an RI generator, had already been constructed in 2010 at RIKEN Nishina Center to realize electron scattering experiments for short-lived nuclei with SCRIT technique. Purpose: Ions of stable nuclei, 133Cs and 132Xe, were used as targets to evaluate the performance of this facility. Methods: In the testing experiment, the energy of electron beam was set to 150 MeV. The stored electron beam current was ∼200 mA with lifetime ∼200 min. To determine the achievable luminosity, elastically scattered electrons were measured by a detection system, which consists of a drift chamber, plastic scintillation detectors and two calorimeters. The trajectories and energies of scattered electrons were determined by the drift chamber and two calorimeters. The detector system covers the scattering angle from 25° to 50°. Results: From the vertex distribution and energy loss in the calorimeters of scattered electrons, the number of elastic scattered electrons from target ions was obtained and the luminosity was determined to be nearly 1027 cm-2·s-1 at beam current 200 mA, which is the required luminosity to determine the charge density distribution of the target nucleus. Conclusion: Except for the RI beam generator, the other parts of SCRIT electron scattering facility have been already constructed. The first experiment for this facility will be elastic electron scattering for short-lived Sn isotopes including a doubly magic nucleus 132Sn in 2015. (author)
[en] Three-dimensional (3D) porous metals, particularly those with a hierarchical porous architecture, are the desirable current collector for a wide variety of electrochemical devices. It is highly desirable to develop a facile process for fabrication of such metallic architectures. Here we propose a novel strategy, oxidization and reduction process, to in situ create micron-scale pores on the ligaments of the commercial Ni foam. Through this simple process, a hierarchical microporous Ni foam (HMNF) composed of large pore channels and micron-scale pores in skeleton is created. This process is simple and green, avoiding the use of sacrificial materials. Furthermore, nanocrystalline MnO2 is coated on a HMNF to construct a supercapacitor electrode. The results indicate that the created micron porous architectures of the HMNF-MnO2 electrode enhance not only the electrochemical performance but also the mechanical robustness, leading to a high capacitance and excellent cycling stability.
[en] Mounting evidence suggests that radiation-induced damage to the hippocampus plays a role in neurocognitive decline for patients receiving whole-brain radiotherapy (WBRT). Hippocampal avoidance whole-brain radiotherapy (HA-WBRT) has been proposed to reduce the putative neurocognitive deficits by limiting the dose to the hippocampus. However, urgency of palliation for patients as well as the complexities of the treatment planning may be barriers to protocol enrollment to accumulate further clinical evidence. This warrants expedited quality planning of HA-WBRT. Pinnacle3 Automatic treatment planning was designed to increase planning efficiency while maintaining or improving plan quality and consistency. The aim of the present study is to evaluate the performance of the Pinnacle3 Auto-Planning on HA-WBRT treatment planning. Ten patients previously treated for brain metastases were selected. Hippocampal volumes were contoured on T1 magnetic resonance (MR) images, and planning target volumes (PTVs) were generated based on RTOG0933. The following 2 types of plans were generated by Pinnacle3 Auto-Planning: the one with 2 coplanar volumetric modulated arc therapy (VMAT) arcs and the other with 9-field noncoplanar intensity-modulated radiation therapy (IMRT). D2% and D98% of PTV were used to calculate homogeneity index (HI). HI and Paddick Conformity index (CI) of PTV as well as D100% and Dmax of the hippocampus were used to evaluate the plan quality. All the auto-plans met the dose coverage and constraint objectives based on RTOG0933. The auto-plans eliminated the necessity of generating pseudostructures by the planners, and it required little manual intervention which expedited the planning process. IMRT quality assurance (QA) results also suggest that all the auto-plans are practically acceptable on delivery. Pinnacle3 Auto-Planning generates acceptable plans by RTOG0933 criteria without time-consuming planning process. The expedited quality planning achieved by Auto-Planning (AP) may facilitate protocol enrollment of patients to further investigate the hippocampal-sparing effect and be used to ensure timely start of palliative treatment in future clinical practice.