Microchimica Acta - The authors report on a microneedle-based amperometric nonenzymatic glucose sensor for painless and continuous monitoring of glucose. It consists of 3 × 5 sharp... 相似文献
Li2O–Al2O3–SiO2 glass-ceramics were prepared with Ta2O5 as nucleating agent, the crystallization mechanism and microstructure evolution were investigated by DTA, XRD, and SEM technologies. With increasing amount of Ta2O5 from 2 to 6 mol%, the crystallization activation energy decreased from 297.73 to 218.66 kJ mol?1, while the crystallization index increased from 1.76 to 3.39. In addition, the cluster of dendritic crystals and lamellar structure obtained in T-2 glass-ceramics indicated a typical two-dimensional crystallization mechanism, and the formation of spherical β-quartz solid solution in T-4 specimens, with average size of 50–70 nm, was mainly due to bulk crystallization mechanism. It was considered that Ta2O5 promoted the nucleation and crystallization of LAS glass by precipitating the crystalline precursor phase of Ta2O5, which acted as nuclei for the subsequent crystal growth. Eventually, the diffusion and crystallization process, microstructure morphology, as well as the secondary grain growth were also investigated. 相似文献
Yttria-stabilized zirconia (YSZ) membranes were deposited onto porous NiO–YSZ anode supports by screen printing. Combined with La0.7Sr0.3MnO3–YSZ composite cathode, the prepared anode-supported solid oxide fuel cells (SOFCs) were electrochemically tested. A typical SOFC with a 30-μm-thick YSZ electrolyte membrane gave the maximum power densities (MPDs) of 0.26, 0.53, 0.78, and 1.03 W/cm2 at 650, 700, 800, and 850 °C, respectively, using hydrogen as fuel and stationary air as oxidant. Replacement of stationary air with pure oxygen flow exerted a significant positive effect on the MPDs of the cell. Using 100- and 200-ml/min oxygen as oxidants, the MPDs of the cell were enhanced 35.3% and 68.6%, respectively. Polarization analysis indicated that, at the MPD points, the electrode polarization resistances accounted for 80% of the cell total resistances.
Recent advances in optical networking technologies, particularly DWDM and MEMS, promise the transmission and switching of huge bandwidth capacity. The carriers have convinced of that their revenue must be earned from efficient bandwidth management instead of unsophisticated increase in capacity. The distributed control plane can offer more flexibility, reliability and scalability, whose functions include addressing, resource and topology discovery, route computation, provisioning and restoration. Generalized Multi-Protocol Label Switching (GMPLS), an IP-centric control plane, inherit the best features of IP and ATM technologies in terms of QoS and traffic engineering. Besides,GMPLS introduces enhancements to the existing IP routing and signaling protocols by supporting not only packet switching networks (IP) and frame/cell switching networks (ATM), but also networks that perform switching in time (e.g. SDH/SONET, PDH, G.709), wavelength (lambdas), and space (fiber) domain. 相似文献
In many engineering optimization problems, the objective and the constraints which come from complex analytical models are often black-box functions with extensive computational effort. In this case, it is necessary for optimization process to use sampling data to fit surrogate models so as to reduce the number of objective and constraint evaluations as soon as possible. In addition, it is sometimes difficult for the constrained optimization problems based on surrogate models to find a feasible point, which is the premise of further searching for a global optimal feasible solution. For this purpose, a new Kriging-based Constrained Global Optimization (KCGO) algorithm is proposed. Unlike previous Kriging-based methods, this algorithm can dispose black-box constrained optimization problem even if all initial sampling points are infeasible. There are two pivotal phases in KCGO algorithm. The main task of the first phase is to find a feasible point when there is no feasible data in the initial sample. And the aim of the second phase is to obtain a better feasible point under the circumstances of fewer expensive function evaluations. Several numerical problems and three design problems are tested to illustrate the feasibility, stability and effectiveness of the proposed method. 相似文献