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Simulations of lithium (Li) impurity transport behaviour with a liquid lithium divertor on the EAST tokamak have been performed using the fluid code EMC3-EIRENE and the Monte Carlo code ITCD. The interactions between particles and the wall surface, like the gyration-induced scrape-off effect, sheath acceleration, kinetic self-sputtering and reflection, are typically ignored or simplified in fluid models. In order to uncover the impacts of the scrape-off effect, sheath acceleration, kinetic self-sputtering and reflection on Li distribution, detailed analysis of the density distributions of Li1+ and Li2+ ions at the divertor region have been carried out by ITCD modelling. The newly-upgraded ITCD code can principally reproduce the distribution patterns of Li ions as well as EMC3-EIRENE under identical plasma conditions on EAST. However, due to the scrape-off effect and sheath acceleration, the densities of Li1+ and Li2+ ions simulated by ITCD are evidently reduced compared to the EMC3-EIRENE simulations. The kinetic self-sputtering by redeposited Li particles in ITCD can increase the densities of the Li ions. Moreover, the kinetic reflection database calculated by SRIM code has been employed by ITCD, which leads to an increase in the Li densities compared to the reflection approach used in EMC3-EIRENE. Overall, by adding the aforesaid physical effects in ITCD, the total number of Li ions shows an obvious reduction compared to the EMC3-EIRENE modelling.

Accurate metering and transport of samples and reagents are a critical process in many microfluidic applications, such as biochemical analysis, diagnostics and drug delivery. However, as the liquid volume to be processed is usually rather small, its sensoring and metering remains a challenging problem. Though some studies on this issue have been reported so far, there is still much room for improvement regarding the metering accuracy, system simplicity and control flexibility. In this work, we propose a simple, automatic and cost-effective method for microfluidic metering and transport. To improve the accuracy, the geometric metering approach with hydrophobic valves of minimum dead volumes is adopted. Besides, an on-chip Bernoulli pump is designed to reduce the hardware requirement, and a pulse width modulation (PWM) scheme is used to facilitate the operation. Testing results show that for metering of 20 μL liquid, the averaged error is − 1.3%, the relative standard deviation is 0.42%. The liquid transport can also be well regulated via PWM method.

The transport properties and line emissions of the intrinsic carbon in the stochastic layer of the Large Helical Device have been investigated with the three-dimensional edge transport code EMC3-EIRENE. The simulations of impurity transport and emissivity have been performed to study the dedicated experiment in which the carbon emission distributions are measured by a space-resolved EUV spectrometer system. A discrepancy of the CIV impurity emission between the measurement and simulation is obtained, which is studied with the variation of the ion thermal force, friction force and the perpendicular diffusivity in the impurity transport model. An enhanced ion thermal force or a reduced friction force in the modelling can increase the CIV impurity emission at the inboard X-point region. Furthermore, the impact of the perpendicular diffusivity Dimp is studied which shows that the CIV impurity emission pattern is very sensitive to Dimp. It is found that the simulation results with the increased Dimp tend to be closer to the experimental observation. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Studies of edge plasma and impurity transport with the toroidally and poloidally localized liquid lithium limiter (LLL) on EAST have been performed by the three-dimensional (3D) edge transport code EMC3-EIRENE. The transport behavior of the Li1+ and Li2+ ions shows a non-axisymmetric distribution in the toroidal direction while an axisymmetric distribution is obtained for the Li3+ ions. The spatial structure of the charge state and excitation radiation patterns of lithium impurity can be understood by using field line tracing, which shows that the Li ions with different charge states exhibit different parallel transport behaviors. The 3D line-integrated LiII emission pattern simulated by EMC3-EIRENE shows a reasonable qualitative agreement with the experiment results measured by the CCD camera system on EAST. An unresolved issue in the LLL experiment is that the species emitting the strong visible spectrum observed around the edge plasma region cannot be distinguished by the current experimental diagnostics on EAST. The detailed numerical analysis of the carbon and deuterium emissions has been carried out to resolve this issue. The simulated deuterium emission pattern shows the same qualitative behavior as the experimental observation at the lower divertor region. The strong radiation experimentally observed at the upper divertor region is perhaps due to the mixing of the lithium and deuterium emissions.

We have performed linear and nonlinear simulations to study the drive mechanism of the quasi-coherent modes (QCM) during the inter-edge localized mode period in HL-2A. With an unstable Resistive-Ballooning mode from linear simulations, the nonlinear simulation has successfully reproduced the QCM inside the separatrix at the outer mid-plane. The poloidal wave number and frequency from fluctuation analysis are almost the same as the experimental results. The phase shift between the electrical potential and the density fluctuation matches. Linear and nonlinear global profile scans show that the QCM is triggered by the density gradient. Based on these scans, some other experimental observations of the QCM are explained.

Zinc oxide (ZnO) spherical nanoparticles (SNPs) and bitter-melon-like (BML) microparticles were synthesized by a hydrothermal route using a zinc (Zn) plate as a source and substrate at various synthesis conditions. The structural analysis confirmed the formation of ZnO with hexagonal wurtzite phase on the hexagonal Zn substrate with growth of the ZnO microparticles along the [1 0 1] direction. The UV–vis absorption spectra of the ZnO microparticles indicated absorption peaks in the UV region which can be attributed to the band gap of ZnO. The room temperature photoluminescence (PL) of the ZnO microparticles exhibited a broad emission band, which is fitted with four Gaussian peaks and were assigned to transitions involving free excitons and various defect centers. The growth model for the formation of ZnO micro- and nanoparticles is presented.

Zirconium oxide (ZrO2 or zirconia) nanostructures were synthesized by a hydrothermal route. Surface morphology analysis depicts the formation of various zirconia nanostructures at different synthesis conditions. X-ray diffraction examination demonstrates that the as-synthesized zirconia is of pure monoclinic phase (m-ZrO2). High resolution transmission electron microscopy (HRTEM) further confirms the high crystalline feature of the m-ZrO2 nanostructures. X-ray photoelectron spectroscopy (XPS) core-level spectra of Zr 3d and O 1s for the ZrO2 nanostructures have been studied to understand further the electronic states and chemical environment of the Zr and O atoms in ZrO2 for different synthesis conditions. XPS results also indicate the existence of oxygen defects and zirconia suboxides which affect the structural and optical properties of zirconia nanostructures. The nanostructures show UV−vis absorption band around 290 nm at room temperature. The band gap energy is determined, in the range of 2.5−3.8 eV ...

Vertically aligned and well interconnected NiO nanowalls with thin nanodiscs of cubic NiO as the in situ formed building blocks were fabricated via a template-free approach. The alkaline solution of ammonium hydroxide was used as a reductant and Ni foil as both source material and substrate for the nanowall synthesis. Surface morphology analysis confirmed the formation of 15 nm thick and 0.2–1.5 μm wide nanowalls. The nanowalls had the crystal structure of cubic NiO with their growth plane along the [111] direction. An optical band gap of about 3.8 eV for the NiO nanowalls was obtained from the optical absorption measurement. NiO nanowalls exhibited a broad UV emission band centered at around 390 nm. This simple, but efficient synthesis technique can facilitate the growth of well aligned 2D nanostructures with large surface area for possible applications in nanoscale devices. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Weak-ferromagnetic (or antiferromagnetic) resonance of Cu and electron spin resonance (ESR) of Gd are observed both in insulating GdSr2Cu2NbO8 and in superconducting GdSr2Cu2RuO8. The Cu resonance implies that the CuO2 planes are magnetic and indicates that the superconducting layer of GdSr2Cu2RuO8 is SrO (not CuO2), as in its related superconducting compound without cuprate planes, doped Sr2YRuO6.

Muon spin rotation measurements are reported for GdSr2Cu2RuO8, a material with an onset temperature for superconductivity of about 45 K (which is virtually the same for its superconducting sister compounds Sr2YRu1− u Cu u O6 and Gd2− z Ce z Sr2Cu2RuO10). The data indicate two magnetic ordering transitions, at about 15 K and about 130 K, in addition to the Gd ordering transition known to occur at about 2.6 K. We tentatively attribute the 130 K transition to Ru and the 15 K transition to Cu ordering, effectively ruling out any superconducting mechanism based on fluctuating magnetic moments, which are frozen below about 15 K. If there is only one mechanism of high-temperature superconductivity, then the three facts that (i) all three sister compounds have essentially the same onset T c for superconductivity and (ii) all three of these compounds contain SrO layers but (iii) only two of the three compounds, GdSr2Cu2RuO8 and Gd2− z Ce z Sr2Cu2RuO10 (and not Sr2YRu1− u Cu u O6) contain cuprate planes imply that ...

We demonstrate here that large area periodic arrays of well-aligned carbon nanotubes can be fabricated inexpensively on Ni dots made by the process of self-assembly nanosphere lithography. These periodic arrays appear colorful due to their efficient reflection and diffraction of visible light. In addition, due to their honeycomb lattice structure, these arrays can act as photonic band gap crystals in the visible frequency range. In this report, we present the initial exploration of the optical properties of such arrays. Here we show that these potential 2D photonic band gap crystal arrays might find very important applications in optoelectronics.

Microstructures of well-aligned multiwall carbon nanotubes grown on patterned nickel nanodots and uniform thin films by plasma-enhanced chemical vapor deposition have been studied by electron microscopy. It was found that growth of carbon nanotubes on patterned nickel nanodots and uniform thin films is different. During growth of carbon nanotubes, a nickel particle sits at the tip of each nanotube, and its [220] is preferentially oriented along the plasma direction, which can be explained by a channeling effect of ions coming into nickel particles in plasma. The alignment of nanotubes is induced by the electrical field direction relative to substrate surface.

GdSr 2 Cu 2 RuO 8 superconducts at an onset temperature T c ≈45 K, and exhibits a low-field magnetic resonance, which the evidence suggests is due to magnetically ordered Cu. Since Bernhard et al. [Phys. Rev. B 59 (1999) 1409] have shown that the magnetism and the superconductivity are homogeneous, it follows that if the cuprate planes are homogeneously magnetic, the superconductivity must be located, not in the cuprate planes, but in the SrO layers. Alternatively there are magnetically ordered Cu impurities on Ru sites, with a locally inhomogeneous magnetization.

Heavily overdoped epitaxial superconducting Tl 2 Ba 2 CuO 6+ δ (Tl-2201) thin films with single superconducting transition temperatures as low as 1.5 K (zero resistance) have been successfully synthesized. The films were made by “off-axis” radiofrequency magnetron sputtering and post-deposition annealing with slow cooling. Our investigations showed that the achievement of a single transition can be attributed to an off-axis configuration during sputter deposition, whereas the reduced T c results from a slow-cooling process immediately after annealing at high temperature. Transmission electron microscopy reveals that the films are pure 2201 phase with good crystallinity and modulated structure. Such samples are very much desired for detailed investigations of upper critical magnetic fields using conventional laboratory superconducting magnets, or the dc facilities at National Laboratories.

The ${}^{99}\mathrm{Ru}$ M\"ossbauer effect has been measured in the ${\mathrm{Sr}}_{2}{\mathrm{Ru}}_{x}{\mathrm{Ir}}_{1\ensuremath{-}x}{\mathrm{O}}_{4}$ system for $x=1.0,$ 0.7, 0.5, and 0.4 at 4.2 K. The isomer shift measurements show a change of -0.05(.02) mm/s as the compound changes from a metal $(x=0.7)$ to an insulator $(x=0.5).$ This isomer shift change is the electronic signature of the metal-insulator transition. All these spectra are single line. At $x=0.4$ the compound undergoes a magnetic phase transition with the measurement of a hyperfine magnetic field of 7.2(1.5) T. The ${}^{99}\mathrm{Ru}$ M\"ossbauer effect has been measured from 1.8 to 147.5 K for ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$ and from these measurements the Debye temperature was estimated to be 427(50) K.

Carbon films were prepared by radio-frequency magnetron sputtering on tungsten substrates. The effect of post-irradiation (40 keV, 4×10 17 ions cm −2 ) with active nitrogen ions and inert argon ions was studied. The results show that combined irradiation with these two kinds ions can transform the carbon film into a carbide film due to induced mixing effects. X-ray diffraction and X-ray photoelectron spectroscopy were used to obtain information on the phases, composition and chemical states of elements at the specimen surface.

Zirconia–yttria films containing 7.0 wt% Y 2 O 3 were prepared by r.f. magnetron sputter deposition followed by 40 keV Ar + ion bombardment and then by electron beam heating. The characterization of the ZrO 2 –Y 2 O 3 thin film structure was carried out by Raman spectroscopy and X-ray diffraction. The Raman spectra of ZrO 2 –Y 2 O 3 films prepared by this technique revealed the monoclinic and tetragonal phase structures. The results of X-ray diffraction showed that the films go through an m–t phase transition and have a microcrystalline structure in the form of the tetragonal phase.

Zirconia-yttria films containing 7 wt% Y 2 O 3 were prepared on Fe substrate by rf magnetron sputter deposition followed by 40 keV oxygen ion irradiation at room temperature. A study was carried out to investigate the chemical states of the elements of the film as well as of the Fe substrate within the interface region between the oxygen ion irradiated ZrO 2 -Y 2 O 3 film and the iron substrate by using X-ray photoelectron spectroscopy (XPS). It was found that the Zr oxidized states were reduced from Zr 4+ on the side of the film to Zr 3+ mixed with a small amount of Zr 2+ with depth in the interface region, and the trend of Y was similar to that of Zr, while Fe as the substrate element entered into the interface region where it was oxidized.

Titanium films are prepared at room temperature by dynamic ion beam mixing where titanium was Ar + ion sputter deposited on an iron-base substrate and simultaneously bombarded with an Ar + beam at an energy of 100 keV. The results of AES analysis show that the produced films can be divided into five sections. The two sections on the surface of the films are contaminated layers which mainly contain carbon and oxygen. The other two sections are the bulk of the film and a transition layer, and the fifth one is a section where titanium atoms enter deep into the iron-base material. These sections of the film are characterized by using XPS analysis and the related mechanism is discussed

The recovery process of 20 vol.-%SiCw/6061 aluminium alloy composite chips has been investigated. The results have shown that, by selecting the proper hot compression parameters, the tensile strengths of recovered composites can reach 85% of the original composite strength. The elastic modulus remained very close to that of the original composite and the binding among the chips was good. Therefore, the recovered composite had a good re-utilisation value.

TiO 2 films were prepared at room temperature by dynamic ion beam mixing where titanium was Ar + sputter deposited on iron substrates and simultaneously bombarded with argon or oxygen ion beams at an energy of 100 keV. The chemical bonding states of the elements on the surface of the films were investigated by X-ray photoelectron spectroscopy (XPS). The XPS results show that carbon on the surface of the films exhibits different states for different bombarding ion species. Argon ion beam bombardment during film deposition induced carbonization forming an O-Ti-C bonding configuration, while oxygen ion bombardment did not. A mechanism related to this phenomenon is suggested.

A high-quality Nd3+ and Mg2+ co-doped LiTaO3 (Nd:MgO:LT) crystal was grown by the Czochralski method. The polarized absorption spectra and fluorescence spectra were studied, and the absorption cross section was calculated by Judd–Ofelt (J–O) theory. The laser performance with different sample cuts of the crystal was investigated for the first time, and it was found that Nd:MgO:LT crystal with different cutting directions (a and c) exhibits different laser properties. By optimizing a partial reflectivity mirror in the laser experimental setting, a high continuous wave output power of 3.58 W was obtained at 1092 and 1076 nm with an optical-to-optical conversion efficiency of 22.78% and slope efficiency of 26.06%. The results indicate that Nd:MgO:LT crystal is a promising candidate for the manufacture of Nd3+ doped periodically poled MgO:LiTaO3 crystal (Nd:PPMgOLT), which should have considerable applications in self-frequency doubling and optical parametric oscillation laser devices.