摘要：电催化二氧化碳还原反应(CO_(2)RR)能够利用可再生电能将CO_(2)转化为高附加值化学品和燃料,是一项有望缓解当下环境挑战的技术方案.本文总结了CO_(2)RR稳足性下降的根本原因,并探讨了解决这一问题的有效策略以及最新的研究进展.首先,在外加电位的作用下,催化剂会发生结构转变,且碳沉积或气体杂质引起的催化剂中毒都会降低CO_(2)RR的稳定性.其次,气体扩散层(GDL)附近发生水淹和盐沉淀会阻碍反应物/生成物的传输,三相界面会受到破坏.在长时间服役时,液压和电流的作用会导致GDL开裂.在电解质方面,碱性电解质会与CO_(2)中和,形成碳酸盐沉淀;而酸性介质腐蚀催化剂,并伴随严重的析氢副反应.另外,电解质中的金属离子杂质的优先还原进一步加剧了稳定性的衰减.深入理解CO_(2)RR中各类失活现象对设计稳定、高效的CO_(2)电催化系统具有指导意义.针对CO_(2)RR稳定性研究目前所面临的困境,本文最后展望了该领域未来的研究方向.

摘要：A complete closed-loop third order s-domain model is analyzed for a frequency synthesizer. Based on the model and root-locus technique, the procedure for parameters design is described, and the relationship between the process,voltage,and temperature variation of parameters and the loop stability is quantitatively analyzed. A variation margin is proposed for stability compensation. Furthermore,a simple adjustable current cell in the charge pump is proposed for additional stability compensation and a novel VCO with linear gain is adopted to limit the total variation. A fully integrated frequency synthesizer from 1 to 1.05GHz with 250kHz channel resolution is implemented to verify the methods.

摘要：Unlike the previous research works analyzing the stability of the T-S （Takagi-Sugeno） fuzzy model, an extension on the stability condition of T-S fuzzy systems with a different strategy is provided. In the strategy a new variable, which is relative to the grade of fuzzy membership function, is introduced to the stability analysis and a new stability conclusion is deduced. The definition of stability condition in this paper is different from previous works, though they are similar in form. With the proposed method, the simulation in flight control law shows a better effectiveness.

摘要：The fuzzy switched PID controller which combines fuzzy PD and conventional PI controller is proposed for ship track-keeping autopilot In this paper. By using rudder angle, the whole voyage is divided into two operating regimes which named transient operating regime and steady operating regime respectively. The fuzzy PD controller is employed in transient operating regime for increasing response, reducing overshoot and shorting transition time. And conventional PI controller is used to improve the stable accuracy in steady operating regime. The global controller is achieved by fuzzy blending of all local controllers. Routh stability criterion is utilized to obtain the stability condition of closed-loop system. The simulation results show the effectiveness of proposed method.

摘要：In this paper,some kinds of linear and nonlinear tracking-differentiators are designed by using suitable exponent functions instead of switch functions,and the stability of these tracking-differentiators is *** the result of simulations,it is manifest that the tracking speeds of these kinds of linear and nonlinear tracking-differentiators are very high,and their design procedures are simple.

摘要：Underwater gliders are efficient mobile sensor platforms that can be deployed for months at a time, traveling thousands of kilometers. Here, we describe our development of a coastal 200 m deep underwater glider, which can serve as an ocean observatory platform operating in the East China Sea. Our glider is developed based on dynamic model analysis: steady flight equilibrium analysis gives the varied range of moving mass location for pitch control and the varied vehicle volume for buoyancy control; a stability analysis is made to discuss the relationship between the stability of glider motion and the location of glider wings and rudder by root locus investigation of glider longitudinal- and lateral-directional dynamics, respectively. There is a tradeoff between glider motion stability and control authority according to the specific glider mission requirements. The theoretical analysis provides guidelines for vehicle design, based on which we present the development progress of the Zhejiang University (ZJU) glider. The mechanical, electrical, and software design of the glider is discussed in detail. The performances of glider key functional modules are validated by pressure tests individually; preliminary pool trials of the ZJU glider are also introduced, indicating that our glider functions well in water and can serve as a sensor platform for ocean sampling.

摘要：The problem of finding stabilizing controllers for switched systems is an area of much research interest as conventional concepts from continuous time and discrete event dynamics do not hold true for these *** solutions have been proposed,most of which are based on finding the existence of a common Lyapunov function(CLF) or a multiple Lyapunov function(MLF) where the key is to formulate the problem into a set of linear matrix inequalities(LMIs).An alternative method for finding the existence of a CLF by solving two sets of linear inequalities(LIs) has previously been *** method is seen to be less computationally taxing compared to methods based on solving *** substantiate this,the computational ability of three numerical computational solvers,LMI solver,cvx,and Yalmip,as well as the symbolic computational program Maple were tested.A specific switched system comprising four second-order subsystems was used as a test *** the obtained solutions,the validity of the controllers and the corresponding CLF was *** was found that all tested solvers were able to correctly solve the *** issue of rounding-off error in numerical computation based software is discussed in *** test revealed that the guarantee of stability became uncertain when the rounding off was at a different decimal *** use of different external solvers led to the same conclusion in terms of the stability of switched *** a result,a shift from using a conventional numerical computation based program to using computer algebra is suggested.

摘要：聚合物电解质在锂金属电池中的应用受限于锂枝晶生长、电化学不稳定性及较低的离子电导率.为解决这些问题,本文通过向三维多孔芳纶纳米纤维(ANF)中填充聚环氧乙烷(PEO)-双三氟甲基磺酰亚胺锂(LiTFSI)电解质,制备了基于三维芳纶纳米纤维网络骨架的柔性ANF/PEO-LiTFSI复合电解质薄膜.由于其独特的构造及离子在三维ANF/PEO-LiTFSI界面中的连续输运,该复合电解质膜具有比PEO-LiTFSI电解质膜更高的力学强度(10.0 MPa)、热稳定性、电化学稳定性(60℃下达4.6 V)和离子电导率,以及较强的抑制锂枝晶能力.基于该复合电解质的固态LiFePO4/Li电池表现出优异的循环性能(在0.4 C下充放电百次后的容量达130 mA h g-1、保持率为93%).该研究提供了一种基于三维骨架设计和制备高性能电解质的有效方法,有望应用于固态锂金属电池.

摘要：In power systems, the Hopf bifurcation (HB) can occur before the saddle-node bifurcation (SNB) and be-comes one of main reasons of voltage instability and collapse, so the bifurcation control for HB has impor-tant significance in improving power system voltage stability. In this paper, the numerical bifurcation analy-sis software MATCONT was used to study bifurcation behavior of a single-machine dynamic-load (SMDL) system with SVC, and the simulation analysis results show that a unstable Hopf bifurcation (UHB) point oc-curring before SNB point and engendering potential harm to voltage stability. To delay or eliminate the UHB phenomenon and enhance voltage stability of the SMDL system with SVC, we designed a sliding mode variable structure controller. The switching function and control variables of the controller are clearly de-scribed and the derivations are directly provided in detail in this paper. The MATLAB simulation results prove that the designed controller can eliminate the UHB point effectively and ensure safe and stable opera-tion of the system.

摘要：In this paper, we examine the problem of designing power system stabilizer (PSS). A new technique is developed using particle swarm optimization (PSO) combined with linear matrix inequality (LMI). The main feature of PSO, not sticking into a local minimum, is used to eliminate the conservativeness of designing a static output feedback (SOF) stabilizer within an iterative solution of LMIs. The technique is further extended to guarantee robustness against uncertainties wherein power systems operation is changing continuously due to load changes. Numerical simulation ahs illustrated the utility of the developed technique.