Accreditation and Quality Assurance - The aim of this work was to establish a mathematical model to identify the main source of measurement uncertainty, quantify each uncertainty component, and... 相似文献
This work was focused on the influence of match degree of structure parameters i.e. molecular size, volume and polarity (denoted as Rd, Vd and Pd) between imprinted cavities in Qu-MIP and Xn on the adsorption selectivity. The results presented that the influence of Rd on the adsorption selectivity was the largest and the most regular, while the influence of Pd was the smallest and the most irregular. Besides, the influence degree of Vd was decreased in general with the increase of Rd. However, as Rd was in the threshold of [0.99, 1.02], Vd would rise to the major influence factor. Furthermore, utilizing data obtained from experiment, the influence authority of Rd, Vd and Pd on the adsorption selectivity was calculated theoretically through multiple linear regression and principal component analysis of IBM SPSS Statistics 20, and results showed the authority order was Rd, Vd and Pd at any circumstance despite the value was different, which was in accordance with the result we directly inducted from the experiment. 相似文献
The aim of this study was to raise the quality control level of Scutellaria indica. A quick and stable ultra performance liquid chromatography method was established for the fingerprint analysis of S. indica. A total of 32 common peaks were marked with 10 batches S. indica detected in 30?min using similarity evaluation system for chromatographic fingerprint of traditional Chinese medicine (2004A version). Besides, a high-resolution mass spectrometer was used to identify flavonoids in S. indica. A total of 27 flavonoids in S. indica were identified. And a series of fragmentation regularities were obtained, which could be used for the identification of other flavonoids. Therefore, the established liquid chromatography–tandem mass spectrometer method could be successfully utilized for the quality control of S. indica. 相似文献
A series of Ni0.37Co0.63S2-reduced graphene oxide nanocomposites with different graphene contents (NCS@rGO-x) has been successfully prepared via a facile one-step hydrothermal method and applied as the catalysts for the oxygen evolution reaction (OER) and degradation of organic pollutants. The XRD and FESEM analyses revealed that the phase structure and morphology of NCS nanoparticles were substantially influenced by the graphene contents. The phase structure of NCS nanoparticles gradually transformed from primary NiCo2S4 to Ni0.37Co0.63S2 and the morphology and size of NCS nanoparticles were found to become more regular and homogeneous with the increase of graphene concentration. On the NCS@rGO-x nanocomposites, the NCS@rGO-2 sample demonstrated the best catalytic activity toward the OER, which delivers a stable current density of 10 mA cm?2 at a small overpotential of ~276 mV (vs. RHE) with a Tafel slope as low as 48 mV dec?1. Furthermore, the NCS@rGO-2 sample showed the remarkable photocatalytic activity for degradation of methylene blue (MB), which may be attributed to the increased reaction sites and high separation efficiency of photogenerated charge carries due to the electronic interaction between NCS nanoparticles and rGO. All these impressive performances indicate that the NCS@rGO-2 nanocomposite is a promising catalyst in energy and environmental fields.
Graphical abstract A series of Ni0.37Co0.63S2-reduced graphene oxide nanocomposites with different graphene contents has been successfully prepared and applied as the catalysts for the oxygen evolution reaction (OER) and degradation of organic pollutants. The NCS@rGO-2 catalyst-modified stainless steel wire mesh (SSWM) electrode delivers a stable current density of 10 mA cm?2 at a small overpotential of ~276 mV (vs. RHE) with a Tafel slope as low as 48 mV dec?1. At the same time, the NCS@rGO-2 catalyst is also first investigated as an efficient photocatalyst for degradation of MB.
Hexagram-like CoS-MoS2 composites were prepared on indium tin oxide (ITO) conductive glasses via cyclic voltammetry electrodeposition using Co(NO3)2 and (NH4)2MoS2 as precursors and tested for application in hydrogen evolution reaction (HER). The structure of CoS-MoS2 composites was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and X-ray photoelectron spectrum (XPS). Electrochemical characterizations indicate that CoS-MoS2 composites exhibit more excellent catalytic activity and stability than MoS2. Compared with pure MoS2, the hexagram-like CoS-MoS2 composites with increased specific surface area improved the density of exposed active sites, and the Co binding S edges in CoS-MoS2 composites promote the number of highly catalytic edge sites and decreased the binding energy △GH. Moreover, the effects of different substrates on the CoS-MoS2 composites were also investigated. Our further understanding of this highly active hydrogen evolution catalyst can facilitate the development of economical electrochemical hydrogen production systems. 相似文献
In this paper, the nonlinear iterative methods, which are different from the classical algorithms, to solve inverse problems are presented. Our methods by denoting some parameters and some properties of the algorithm in both noise and noiseless cases are studied. Finally, the convergence of the sequence generated by the algorithm without noise is discussed. 相似文献
Home owners are typically charged differently when they consume power at different periods within a day. Specifically, they are charged more during peak periods. Thus, in this paper, we explore how scheduling algorithms can be designed to minimize the peak energy consumption of a group of homes served by the same substation. We assume that a set of demand/response switches are deployed at a group of homes to control the activities of different appliances such as air conditioners or electric water heaters in these homes. Given a set of appliances, each appliance is associated with its instantaneous power consumption and duration, our objective is to decide when to activate different appliances in order to reduce the peak power consumption. This scheduling problem is shown to be NP-Hard. To tackle this problem, we propose a set of appliance scheduling algorithms under both offline and online settings. For the offline setting, we propose a constant ratio approximation algorithm (with approximation ratio \(\frac{1+\sqrt{5}}{2}+1\)). For the online setting, we adopt a greedy algorithm whose competitive ratio is also bounded. We conduct extensive simulations using real-life appliance energy consumption data trace to evaluate the performance of our algorithms. Extensive evaluations show that our schedulers significantly reduce the peak demand when compared with several existing heuristics. 相似文献
In this paper, we obtain universal inequalities for the eigenvalues of the Dirichlet problem and clamped plate problem of drifting Laplacian on (\(n+1\))-dimensional (\(n\ge 4\)) complete noncompact simply connected smooth metric measure spaces which meet some conditions of the sectional curvature and radial weighted Ricci curvature. 相似文献
This paper deals with the time-optimal control problem for a class of fractional order systems. An analytic solution of the time-optimal problem is proposed, and the optimal transfer route is provided. Considering it is usually adopted in the discrete situation for actual control system, the sampling date may induce chattering phenomenon, an alternative sub-optimal solution is constructed. Additionally, the special and meaningful application of fractional order tracking differentiator is introduced to explain our main results. The effectiveness and advantages of the proposed method have been illustrated by numerical examples. 相似文献