Novel Stabilization Conditions for Uncertain Singular Systems with Time-Varying Delay

The problem of delay-dependent robust stabilization for continuously singular time-varying delay systems with norm-bounded uncertainties is investigated in this paper. First, based on some mathematical transform, the uncertain singular system is described in a form which involves the time-delay integral items. Then, in terms of the delay-range-dependent Lyapunov functional and the LMI technique, the improved delay-dependent LMIs-based conditions are established for the uncertain singular systems with time-varying delay to be regular, causal, and stable. Furthermore, by solving these LMIs, an explicit expression for the desired state feedback control law can be obtained; thus, the regularity, causality, and stability of the closed-loop system are guaranteed. In the end, numerical examples are given to illustrate the effectiveness of the proposed methods

Electroacupuncture at LI11 promotes jejunal motility via the parasympathetic pathway

Background: Gastrointestinal motility disorder has been demonstrated to be regulated by acupuncture treatment. The mechanisms underlying the effects of acupuncture stimulation of abdominal and lower limb acupoints on gastrointestinal motility have been thoroughly studied; however, the physiology underlying the effects of acupuncture on the forelimbs to mediate gastrointestinal motility requires further exploration. The aim of this study was to determine whether electroacupuncture (EA) at LI11 promotes jejunal motility, whether the parasympathetic pathway participates in this effect, and if so, which somatic afferent nerve fibres are involved.Methods: A manometric balloon was used to observe jejunal motility. The effects and mechanisms of EA at LI11 were explored in male Sprague-Dawley rats with or without drug administration (propranolol, clenbuterol, acetylcholine, and atropine) and with or without vagotomy. Three types of male mice (β1β2 receptor-knockout [β1β2 −/−] mice, M2M3 receptor-knockout [M2M3 −/−] mice and wild-type [WT] mice) were also studied by using different EA intensities (1, 2, 4, 6, and 8 mA). A total of 72 rats and 56 mice were included in the study.Results: EA at LI11 increased the contractile amplitude of jejunal motility in the majority of both rats and mice. However, EA at LI11 did not enhance jejunal motility in rats administered atropine, rats that underwent vagotomy, and M2M3 −‍‍/− mice (at all intensities). In WT mice, EA at LI11 significantly increased jejunal motility at all intensities except 1 mA, and a plateau was reached at intensities greater than 4 mA.Conclusion: Our results suggest that EA at LI11 promotes jejunal motility primarily by exciting the parasympathetic pathway, and that Aδ-fibres and C-fibres may play important roles in the process

Simplified process for making anode copper

In conventional copper production, anode copper is produced from concentrate in three furnaces in a process that entails four oxidation steps and one reduction step. Three types of slags are produced that require further treatment to recover copper. Dongying Fangyuan Nonferrous Metals recently developed a simplified process which requires only two custom-designed furnaces instead of the conventional smelting, converting and refining furnaces. The first furnace continuously produces high-grade matte (>75, wt% Cu) that contains little iron

Novel Stabilization Conditions for Uncertain Singular Systems with Time-Varying Delay

The problem of delay-dependent robust stabilization for continuously singular time-varying delay systems with norm-bounded uncertainties is investigated in this paper. First, based on some mathematical transform, the uncertain singular system is described in a form which involves the time-delay integral items. Then, in terms of the delay-range-dependent Lyapunov functional and the LMI technique, the improved delay-dependent LMIs-based conditions are established for the uncertain singular systems with time-varying delay to be regular, causal, and stable. Furthermore, by solving these LMIs, an explicit expression for the desired state feedback control law can be obtained; thus, the regularity, causality, and stability of the closed-loop system are guaranteed. In the end, numerical examples are given to illustrate the effectiveness of the proposed methods.Peer Reviewe

Effects of Cemented Porous Media on Temporal Mixing Behavior of Conservative Solute Transport

The cementation of porous media leads to the variation of the pore space and heterogeneity of the porous media. In this study, four porous media (PM1, PM2, PM3, and PM4) with the different radii of solid grains were generated to represent the different cementation degrees of the porous media. The direct simulations of flow and conservative solute transport in PM1–4 were conducted to investigate the influence of the cemented porous media and Peclet number (Pe) on the temporal mixing behavior. Two metrics, scalar dissipation rates (SDR) and dilution index, were employed to quantify the temporal mixing behavior. It was found that the spatial velocity variability of the flow field was enhanced as cementation degree increased. The results of the coefficient of velocity variation ( C V U ) increased from 0.943 to 2.319 for PM1–4. A network consisted of several preferential flow paths was observed in PM1–4. The preferential flow enhanced the mixing of the conservative solute but had a negative influence on the mixing of the solute plume when the cemented solid grains formed several groups, and there were some stagnant regions where the flow was almost immobile. As the Pe increased, for PM1–3, the exponent of the best-fitting power law of the global SDR decreased. At the case of Pe = 400, the slope of the global SDR reduced to around −1.9. In PM4 where the preferential flow was enhanced by the cemented solid grains, the slope of the global SDR increased as the Pe increased. The global SDR results indicated that the temporal mixing behavior followed a Fickian scaling ( S D R ∝ p v − 1.5 ) in the early stage (Pv < 0.05), while the mixing behavior turned to be non-Fickian in the late stage. The transition time from the Fickian scaling to the non-Fickian scaling was found to be sensitive to the cementation degree of the porous media

A method of high-quality silica preparation from copper smelting slag

High-quality silica was prepared from copper smelting slag through a method of in situ modification.The effects of the addition of an amount of polyethylene glycol-6000 as a modifier, the modification temperature and the modified endpoint pH on the particle size and specific surface area of the silica were systematically studied. It has been shown that the particle size, specific surface area, and the interstices between the particles were greatly affected by the modification temperature and the pH of the modification endpoint.Optimal conditions are: modifier 10% as solute mass, modification temperature 40°C, and pH of modification endpoint 8.5. Under these conditions, the silicon sinking rate was as high as 97.82%, the prepared silica particles had good dispersibility, the average particle size was 20\ua0nm, the particle morphology was spherical, and the specific surface area was as high as 244.67\ua0m/g, which was superior to A-grade standard of HG/T3061-1999 and ISO 5794-1:2005(E), and could be directly used in the rubber industry

Structural Exfoliation of Layered Cathode under High Voltage and Its Suppression by Interface Film Derived from Electrolyte Additive

Layered cathodes for lithium-ion battery, including LiCo_{1–<i>x</i>–<i>y</i>}Ni_<i>x</i>Mn_<i>y</i>O₂ and <i>x</i>Li₂MnO₃·(1–<i>x</i>)­LiMO₂ (M = Mn, Ni, and Co), are attractive for large-scale applications such as electric vehicles, because they can deliver additional specific capacity when the end of charge voltage is improved to over 4.2 V. However, operation under a high voltage might cause capacity decaying of layered cathodes during cycling. The failure mechanisms that have been given, up to date, include the electrolyte oxidation decomposition, the Ni, Co, or Mn ion dissolution, and the phase transformation. In this work, we report a new mechanism involving the exfoliation of layered cathodes when the cathodes are performed with deep cycling under 4.5 V in the electrolyte consisting of carbonate solvents and LiPF₆ salt. Additionally, an electrolyte additive that can form a cathode interface film is applied to suppress this exfoliation. A representative layered cathode, LiCoO₂, and an interface film-forming additive, dimethyl phenylphosphonite (DMPP), are selected to demonstrate the exfoliation and the protection of layered structure. When evaluated in half-cells, LiCoO₂ exhibits a capacity retention of 24% after 500 cycles in base electrolyte, but this value is improved to 73% in the DMPP-containing electrolyte. LiCoO₂/graphite full cell using DMPP behaves better than the Li/LiCoO₂ half-cell, delivering an initial energy density of 700 Wh kg ^–1 with an energy density retention of 82% after 100 cycles at 0.2 C between 3 and 4.5 V, as compared to 45% for the cell without using DMPP

Additional file 1: of Electroacupuncture at LI11 promotes jejunal motility via the parasympathetic pathway

Genetic background of gene knockout mice. (DOCX 195 kb