基于CMIP5的中国西北地区暖湿化演变研究

为了解中国西北地区历史与未来时期的气候演变趋势,以CMFD再分析数据集及CMIP5全球气候模式输出数据为基础,从时空维度详细分析了西北地区历史气候的演变特征并对区域未来气候发展进行了预估。结果表明：1979-2018年西北地区的气温、降水量以及近地面空气比湿均呈现出明显的增加趋势,且未来极有可能继续增加;此外,降水量在年内的分配过程越趋均匀化,且降水结构在2001年左右发生了较大突变。整体来看,西北地区的历史气候演变显示出高度的暖湿化倾向。未来情景下,西北地区的气候将继续朝暖湿化方向发展,同时降水量的年内分配不均匀性也将进一步减小,且在RCP8.5排放情景下表现的更为突出。本研究可为西北地区气候变化的影响评估提供参考,同时也为水利、农业、气象和生态等部门的决策提供科学依据。     

基于关键闸坝优选的区域水网水量调控

为实现区域水网水量的高效调控,从水量、水生态、水质和闸坝管理等4个方面构建包含10个指标的闸坝优选评价指标体系,以廊坊市凤河-永定河区域水网为研究对象,计算区域内32座闸坝的综合关键指数并给出影响程度排序,采用水动力数学模型验证关键闸坝选取的合理性。结果表明：优选出的永丰闸和东张务闸是区域水网的关键闸坝,通过调节这两座闸坝的开度即可满足区域水网的生态需水和防洪排涝调度目标,保持区域水网较优的水力连通能力,提高区域水网水量调控效率。     

三网融合中的安全风险及防范技术研究

文章分析了三网融合中可能出现的网络和内容安全的隐患,提出了通过认证机制、防护机制、监控机制及信任机制等技术来应对。同时,文章还深入分析了三网融合下信息安全监管问题,提出继续加强融合法律法规建设,适时成立统一融合监管机构,建立融合统一监管标准体系,以及全面纳入信息安全保障体系等一系列三网融合信息安全监管的建议。     

New results on robust output regulation of nonlinear systems with a nonlinear exosystem

The global robust output regulation problem for nonlinear plants subject to nonlinear exosystems has been a challenging problem and has not been well addressed. The main difficulty lies in finding a suitable internal model. The existing internal model for handling the nonlinear exosystem is not zero input globally asymptotically stable, and can only guarantee a local solution for the output regulation problem. In this paper, we first propose a new class of internal models, which is guaranteed to exist under the generalized immersion condition. An advantage of this internal model is that it is zero input globally asymptotically stable. This fact will greatly facilitate the global stabilization of the augmented system associated with the given plant and the internal model. Then we will further utilize this class of internal models to solve the global robust output regulation problem for output feedback systems with a nonlinear exosystem. Copyright © 2011 John Wiley & Sons, Ltd.     

Globally asymptotic stabilization for nonlinear time-delay systems with ISS inverse dynamics

The output feedback stabilization is considered for a class of nonlinear time-delay systems with inverse dynamics in this paper.An appropriate state observer is constructed for the unmeasurable system states in order to realize the control objective.By adopting the backstepping and Lyapunov-Krasovskii functional methods,a systematic design procedure for a memoryless output feedback control law is presented.It is shown that the designed controller can make the closed-loop system globally asymptotically stable while keeping all signals bounded.An illustrative example is discussed to show the effectiveness of the proposed control strategy.     

Alternative Method of Solution of the Regulator Equation: L2‐Space Approach

An alternative method for the proof of solvability of the differential equation that is a part of the regulator equation which arises from the solution of the output regulation problem. The proof uses the L²‐space based theory of solutions of partial differential equations for the case of the linear output regulation problem. In the nonlinear case, a sequence of linear equations is defined so that their solutions converge to the solution of the nonlinear problem. This is proved using the Banach Contraction Theorem. Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

多能互补系统综合效益最大化控制

针对光伏发电出力随机性大,波动较强等问题,提出了一种多能互补系统综合效益最大化控制策略,控制双向DC-DC逆变器实现蓄电池、超级电容器和氢燃料电池充放电,保证直流母线电压的稳定。然后利用蓄电池和超级电容器所具有的能量互补特点,实现对储能系统的优化管理。采用光伏与混合储能协调互补的方法,可以减少储能系统的容量、降低蓄电池循环充放电的次数、延长储能装置的使用寿命,并获得较好的光伏波动平抑效果,相比于常规的控制方法,减少了运行投资成本,具有显著的经济效益。     

高等教育服务承诺与政府规制改革

高等教育服务是一个具有时代特征的历史现象 ,在当前显露出全球化背景下经济行为与文化行为互动性特征 ,站在综合国力提升和国际竞争力增强的战略高度审视高等教育服务贸易的长远影响至关重要。通过政府规制改革 ,建立起本国能够负责任地采纳并被其他成员国创造性地适应的高等教育及其服务贸易发展模式是各国政府的重要责任     

10 kV变频器在输油站离心泵电机控制的应用

为了验证异步电机变频调速在输油站应用的实际应用效果,进行了变频调速泵(离心泵)的工作特性分析、运动流体的能量分析和电机功率因数的分析。然后,对某输油站串联安装且同时运行的变频离心泵和非变频(工频)离心泵近一年的运行数据进行分析验证。理论分析和数据统计分析的结果一致。结果表明异步电动机变频调速(降频)运行后,节能效果显著,且输油管道压力调节范围更大,提高了电机的功率因数。