In the last few years, the critical current densities of long commercially available REBa2Cu3O7?x (RE-123, where RE represents Y or a rare earth element) coated conductors have reached values of 250 A/cm-width at 77 K and zero applied field. Even higher values of 600 A/cm-w (77 K, B = 0) have been demonstrated in shorter lengths. The attractive features of the use of these high-Tc superconductors (HTS) are operation temperatures above 20 K and/or magnetic fields higher than those envisaged for the ITER TF coils. Possible operation conditions for HTS fusion magnets have been studied taking into consideration the possible further improvements of RE-123 coated conductors. Investigations of stability and quench behavior indicate that stability is not a problem, whereas quench detection and protection need attention. Because of the high currents necessary for fusion magnets, many tapes need to be assembled into a transposed conductor. The qualification of HTS conductors for fusion magnets would require their test at magnetic fields of 11 T and currents well above 10 kA. The possibilities to test straight HTS conductor samples in SULTAN have been considered. For a test at 4.5 K, only the development of a low resistance joint between the HTS conductor under test and the NbTi transformer of SULTAN would be necessary. Tests up to 20 K would require that the HTS sample is connected with the NbTi transformer by a conduction-cooled HTS bus bar of large thermal resistance similar to the HTS module of a current lead. HTS conductor tests at temperatures around 50 K would be possible with modified cryogenics. 相似文献
The present paper addresses a new compact low-power high-speed output buffer amplifier topology for large-size liquid crystal
display applications. The suggested buffer achieves fast driving performance, draws a low quiescent current during static
operation and offers a rail-to-rail common-mode input range. The circuit provides enhanced slewing capabilities with a limited
power consumption by simultaneously exploiting the push–pull output sections of two basic complementary-type input amplifiers
to realize a dual-path push–pull operation of the output stage. An auxiliary biasing network integrated in the input differential
stage allows the quiescent bias conditions of the class-AB output stage to be inherently controlled without additional current
dissipation. Post-layout simulation results confirm that the proposed amplifier can drive a 1-nF column line load within a
0.9-μs settling time under a 3-V full voltage swing, while drawing only 3.5-μA quiescent current. Monte Carlo simulations
are finally carried out, showing a good degree of robustness of the proposed output buffer against process and mismatch variations. 相似文献
This paper discusses the sensitivity of the aerodynamic behavior of a trapezoidal-shaped bridge deck cross-section to its lower corner degree-of-sharpness and to the incoming flow turbulence integral length scale in conjunction with low turbulence intensity. Since these features are hard to set and measure in experimental facilities, the aerodynamic behavior of the body has been investigated through the computational simulation of the flow around it. The results are given in term of force coefficients, Strouhal number, pressure distribution along its surface, and the mean and instantaneous flow patterns. Dramatic changes in the force coefficients and Strouhal number occur following small changes in the parameter values. These changes have been found to be due to significant modifications in the topological structure of the flow. Special emphasis has been given to the analysis of the separation and reattachment points, the recirculation bubble length, the vortex shedding mechanisms and the wake structures. On the basis of the results, four aerodynamic regimes have been pointed out in analogy with the well-known individual Re number regimes. Some of these regimes have also been recognized on the deck section with the considered sharpest and smoothest lower edge treatments, i.e. for the highest and lowest degrees-of-sharpness. 相似文献
An efficient and simple method for determination of methyl anthranilate (MA) in Citrus spp. honeys by headspace-solid-phase microextraction-gas chromatography (HS-SPME-GC) was developed and validated. Experimental design was used to investigate the effects of the principal extraction parameters. The central composite design (CCD) and the desirability function were used to find the experimental conditions providing the optimal HS-SPME result. Validation was carried out in terms of specificity, linearity, limit of detection (LOD) and quantitation (LOQ) (0.149 and 0.324 μg/g, respectively), method precision (RSD 7%), LOQ precision (RSD 6.5%), and was resulted accurate and robust. Finally, the applicability of the method to the determination of MA in a number of commercial Citrus spp. honey samples was demonstrated, the content ranged from 0.63 to 3.26 μg/g. 相似文献
The paper aims to show how regional policy‐makers can stimulate firms' co‐operation with research organizations by granting an R&D subsidy. Using an original dataset for the Italian region of Emilia‐Romagna, propensity score matching is first applied to identify the impact of the subsidy received. A generalized propensity score technique is then employed to investigate the effect of an increasing amount of support. The firm's co‐operation is policy sensitive. The award of a subsidy to regional firms affects their intra‐regional more than their extra‐regional co‐operation. The propensity toward the latter appears subject to a monetary effect and is influenced by the amount of public funding received providing the subsidy overcomes a minimum threshold. 相似文献
A convenient photochemical flow protocol for the formation of aryl‐carbon bonds via photogenerated phenyl cations has been developed. A wide range of phenylated products, including biaryls, allylarenes, 2‐arylacetals and benzyl γ‐lactones, was smoothly synthesized in satisfactory yields under metal‐free conditions. The adoption of a flow reactor often allowed us to adopt higher concentrations of substrates and shorter irradiation times compared to those usually employed in batch systems.
This paper investigates the removal of formic acid by unacclimated biomass from a municipal activated sludge wastewater treatment plant. The biomass was initially able to remove formic acid, but its removal rate and Oxygen Uptake Rate (OUR) decreased with time, until formic acid removal stopped before the formic acid had been exhausted. Formaldehyde was removed in a similar way, whereas the same biomass was simultaneously able to grow and store PHAs when acetic acid was used as substrate.Batch tests with glycine and 13C NMR analysis were performed, showing that unacclimated biomass was not able to synthesize all the metabolic intermediates from formic acid alone. At least glycine needed to be externally supplemented, in order to activate the serine synthesis pathway. A small amount of formic acid removal in the absence of growth was also possible through formaldehyde formation and its further conversion to formalin (1,2-formaldehyde dimer), whereas no PHAs were formed. 相似文献
Spherical silica nanoparticles containing fluorescent trimethine indocyanine dyes (λabs = 547 nm, λem = 570 nm) were prepared using a water-in-oil microemulsion method. The nanoparticles were of 50 nm diameter and were almost monodispersed in aqueous solution at pH 5.5. Entrapment of dye molecules in the silica matrix stabilised photoemission over several hours of continuous irradiation. The photoemission intensity of the indocyanine was increased 13-fold over that recorded in solution. As each nanoparticle contained 110 dye molecules, the photoemission brightness of each particle was enhanced by three orders of magnitude. The fluorescent nanoparticles have been tested as imaging tools in in vitro tests. As an example of non-macrophagic cells, a highly differentiated neuronal cell line (GT1-7) was used and the results showed that the prepared nanoparticles can be incorporated into these cells with no apparent toxicity for up to three days. 相似文献