The study on the conductivity of styrene-maleic anhydride copolymer electrolytes based on poly(ethylene glycol)400 and LiClO4

Polyelectrolytes, in this study were synthesized from styrene-maleic anhydride (SMA) copolymer, poly(ethylene glycol)400 (PEG400), and lithium perchlorate (LiClO₄). Fourier transform infrared spectroscopy (FTIR), and http://ars.els-cdn.com/content/image/1-s2.0-S001346860400180X-si3.gif"> magic angle spinning (MAS) solid-state NMR were used to monitor the interaction between Li⁺ ions and polymer. The results of FTIR and http://ars.els-cdn.com/content/image/1-s2.0-S001346860400180X-si4.gif"> MAS solid-state NMR indicate the Li⁺ ions are preferentially coordinated to the ether oxygen of PEG. The T_g of the PEG segments in polyelectrolyte increases with LiClO₄ concentration, as determined by differential scanning calorimetry (DSC), indicating that solubility of the Li⁺ ions in the host polymer increases with the PEG content. Impedance spectroscopy (IS) shows that the bulk conductivity of polyelectrolytes and the conductivity behavior obeys the Vogel-Tamman-Fulcher (VTF) equation.     

An LMI approach to synthesis subject to almost asymptotic regulation constraints

A multi-objective controller synthesis problem is considered in which an output is to be regulated approximately by assuring a bound on the steady-state peak amplification in response to an infinite-energy disturbance, while also guaranteeing a desired level of performance measured in terms of the worst-case energy gain from a finite-energy input to a performance output. Relying on a characterization of the controllers with which almost asymptotic regulation is accomplished, the problem of guaranteeing the desired level of performance is reduced to solving a system of linear matrix inequalities subject to a set of linear equality constraints. Based on the solution of this system, a procedure is outlined for the construction of a suitable controller whose order is equal to the order of the plant plus the order of the exogenous system.     

Controller synthesis with guaranteed closed-loop phase constraints

In this paper, we present an analysis and synthesis approach for guaranteeing that the phase of a single-input, single-output closed-loop transfer function is contained in the interval [−α,α] for a given α>0 at all frequencies. Specifically, we first derive a sufficient condition involving a frequency domain inequality for guaranteeing a given phase constraint. Next, we use the Kalman–Yakubovich–Popov theorem to derive an equivalent time domain condition. In the case where http://www.sciencedirect.com/cache/MiamiImageURL/B6V21-4TVJ07S-1-26/0?wchp=dGLbVlW-zSkzk" alt="View the MathML source" title="View the MathML source" align="absbottom" border="0" height=16 width="39"/>, we show that frequency and time domain sufficient conditions specialize to the positivity theorem. Furthermore, using linear matrix inequalities, we develop a controller synthesis approach for guaranteeing a phase constraint on the closed-loop transfer function. Finally, we extend this synthesis approach to address mixed gain and phase constraints on the closed-loop transfer function.     

中国环境艺术的系统化设计

文章通过中国环境艺术的系统化设计内涵及方法论的研究,从设计角度出发,对中国环境艺术设计的现状做出了明确的总结并且提出对于中国环境艺术设计在未来的展望,从此达到人与环境和谐共生,可持续发展的目的。     

A reactive GRASP and path relinking for a combined production–distribution problem

An NP-hard production–distribution problem for one product over a multi-period horizon is investigated. The aim is to minimize total cost taking production setups, inventory levels and distribution into account. An integer linear model is proposed as a compact problem specification but it cannot be solved to optimality for large instances. Instead of using a classical two-phase approach (production planning and then route construction for each day), metaheuristics that simultaneously tackle production and routing decisions are developed: a GRASP (greedy randomized adaptive search procedure) and two improved versions using either a reactive mechanism or a path-relinking process. These algorithms are evaluated on 90 randomly generated instances with 50, 100 and 200 customers and 20 periods. The results confirm the interest of integrating production and distribution decisions, compared to classical two-phase methods. Moreover, reaction and path-relinking give better results than the GRASP alone.     

《电镀与涂饰》杂志网店开业

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《电镀与涂饰》杂志网店开业

正随着网络的飞速发展,应广大读者要求,《电镀与涂饰》杂志开通网店。读者通过网店购买杂志、图书、光盘、资料等,可享受邮费折扣、礼品赠送等优惠。欢迎广大读者访问购买。网店网址:http://www.plating.org/wsdy.htm。     

《电镀与涂饰》杂志网店开业

随着网络的飞速发展,应广大读者要求,《电镀与涂饰》杂志开通网店。读者通过网店购买杂志、图书、光盘、资料等,可享受邮费折扣、礼品赠送等优惠。欢迎广大读者访问购买。网店网址:http://www.plating.org/wsdy.htm。     

Dynamic Changes in Reactive Oxygen Species in the Shoot Apex Contribute to Stem Cell Death in Arabidopsis thaliana

In monocarpic plants, stem cells are fated to die. However, the potential mechanism of stem cell death has remained elusive. Here, we reveal that the levels of two forms of reactive oxygen species (ROS), superoxide anion free radical () and hydrogen peroxide (H₂O₂), show dynamic changes in the shoot apex during the plant life cycle of Arabidopsis thaliana. We found that the level of decreased and disappeared at four weeks after bolting (WAB), while H₂O₂ appeared at 3 WAB and showed a burst at 5 WAB. The timing of dynamic changes in and H₂O₂ was delayed for approximately three weeks in clv3-2, which has a longer lifespan. Moreover, exogenous application of H₂O₂ inhibited the expression of the stem cell determinant WUSCHEL (WUS) and promoted the expression of the developmentally programmed cell death (dPCD) marker gene ORESARA 1 (ORE1). These results indicate that H₂O₂ triggers an important signal inducing dPCD in stem cells. Given that plays roles in maintaining WUS expression and stem cell activity, we speculate that the dynamic shift from to H₂O₂ in the shoot apex results in stem cell death. Our findings provide novel insights for understanding ROS-mediated regulation during plant stem cell death.