检索结果-南通市图书馆

同方期刊数据库

Delay-dependent stability and stabilization of a class of linear switched time-varying delay systems

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2007年第2期18卷 320-326页

作者： Zhang Lixian Wang changhong gao Huijun Space Control and Inertial Technology Research Center Harbin Inst. of Technology Harbin 150001 P. R. China

The stability and stabilization of a class of linear switched time-varying delay systems are investigated. A piecewise quadratic Lyapunov function （PWQLF） is constructed and is used to obtain the stability conditions based on the linear matrix inequalities （LMIs）. The stabilizing controller for this class of system is then designed and the solution of the desired controller can be obtained by a cone complementary linearization algorithm. Numerical examples are provided to illustrate the less conservativeness of the new stability and the validity of the controller design procedures.

关键词： Linear switched systems Time-varying delay Delay-dependent stability Stabilization LMIs.

Sliding mode H_∞ control for a class of uncertain nonlinear state-delayed systems

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2006年第3期17卷 576-585页

作者： Wu Ligang Wang changhong gao Huijun Zhang Lixian Space Control and Inertial Technology Research Center Harbin Inst. of Technology Harbin 150001 P. R. China

A new proportional-integral （PI） sliding surface is designed for a class of uncertain nonlinear state-delayed systems. Based on this, an adaptive sliding mode controller （ASMC） is synthesized, which guarantees the occurrence of sliding mode even when the system is undergoing parameter uncertainties and external disturbance. The resulting sliding mode has the same order as the original system, so that it becomes easy to solve the H∞ control problem by designing a memoryless H∞ state feedback controller. A delay-dependent sufficient condition is proposed in terms of linear matrix inequalities （LMIs）, which guarantees the sliding mode robust asymptotically stable and has a noise attenuation level γ in an H∞ sense. The admissible state feedback controller can be found by solving a sequential minimization problem subject to LMI constraints by applying the cone complementary linearization method. This design scheme combines the strong robustness of the sliding mode control with the H∞ norm performance. A numerical example is given to illustrate the effectiveness of the proposed scheme.

关键词： sliding mode control H∞ control nonlinearity state-delayed system linear matrix inequality (LMIs)

在线全文

学校读者我要写书评

暂无评论

烷基葡萄糖苷作为降滤失助剂的研究

石油钻探技术 2000年第1期28卷 31-32页

作者：高长虹胜利石油管理局胜利采油厂山东东营257041

首次报道了烷基葡萄糖苷(APG)作为降滤失助剂的研究。研究结果表明,烷基葡萄糖苷在聚合物钻井液中具有较好的降滤失性能,对聚合物钻井液的耐温性也有好的影响。而且烷基葡萄糖苷与甲基糖苷复配后既可降低钻井液的滤失量,抑制性又好,从... 详细信息

首次报道了烷基葡萄糖苷(APG)作为降滤失助剂的研究。研究结果表明,烷基葡萄糖苷在聚合物钻井液中具有较好的降滤失性能,对聚合物钻井液的耐温性也有好的影响。而且烷基葡萄糖苷与甲基糖苷复配后既可降低钻井液的滤失量,抑制性又好,从而形成了一种新型钻井液体系——糖基聚合物钻井液。

关键词：聚合物钻井液降滤失剂烷基葡萄糖苷助剂

Design of multifunctional interfaces on ceramic solid electrolytes for high-performance lithium-air batteries

在线全文

学校读者我要写书评

暂无评论

Green Energy & Environment 2025年第1期10卷 183-192页

作者： Yunxin Shi Ziyang Guo changhong Wang Mingze gao Xiaoting Lin Hui Duan Yonggang Wang Xueliang Sun College of Energy Material and Chemistry College of Chemistry and Chemical EngineeringInner Mongolia UniversityHohhot010021China Department of Mechanical and Materials Engineering Western UniversityLondonONN6A 5B9Canada Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Institute of New EnergyiChEM(Collaborative Innovation Center of Chemistry for Energy Materials)Fudan UniversityShanghai200433China Eastern Institute for Advanced Study Eastern Institute of TechnologyNingboZhejiang315100China

High-energy-density lithium(Li)–air cells have been considered a promising energy-storage system,but the liquid electrolyte-related safety and side-reaction problems seriously hinder their *** address these above issues,solid-state Li–air batteries have been widely ***,many commonly-used solid electrolytes generally face huge interface impedance inLi–air cells and also showpoor stability towards ambient air/Li ***,we fabricate a differentiating surface-regulated ceramic-based composite electrolyte(DSCCE)by constructing disparately LiI-containing polymethyl methacrylate(PMMA)coating and Poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)layer on both sides of Li_(1.5)Al_(0.5)Ge_(1.5)(PO_(4))_(3)(LAGP).The cathode-friendly LiI/PMMA layer displays excellent stability towards superoxide intermediates and also greatly reduces the decomposition voltage of discharge products in Li–air ***,the anode-friendly PVDF-HFP coating shows low-resistance properties towards ***,Li dendrite/passivation derived from liquid electrolyte-induced side reactions and air/I-attacking can be obviously suppressed by the uniformand compact composite *** a result,the DSCCE-based Li–air batteries possess high capacity/low voltage polarization(11,836mAh g^(-1)/1.45Vunder 500mAg^(-1)),good rate performance(capacity ratio under 1000mAg^(-1)/250mAg^(-1) is 68.2%)and longterm stable cell operation(~300 cycles at 750 mA g^(-1) with 750 mAh g^(-1))in ambient air.

关键词： Li-air batteries Li_(1.5)Al_(0.5)Ge_(1.5)(PO_(4))_(3) Polymers Composite electrolyte Ambient air

Sliding mode control of uncertain systems with distributed time-delay: parameter-dependent Lyapunov functional approach

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

控制理论与应用（英文版） 2006年第2期4卷 159-167页

作者： Ligang WU changhong WANG Huijun gao Qingshuang ZENG Space Control and Inertial Technology Research Center Harbin Instimt of Technology Harbin Heilongjiang 150001 China

The robust stability and robust sliding mode control problems are studied for a class of linear distributed time-delay systems with polytopic-type uncertainties by applying the parameter-dependent Lyapunov functional approach combining with a new method of introducing some relaxation matrices and tuning parameters, which can be chosen properly to lead to a less conservative result. First, a sufficient condition is proposed for robust stability of the autonomic system; next, the sufficient conditions of the robust stabilization controller and the existence condition of sliding mode are developed. The results are given in terms of linear matrix inequalities （LMIs）, which can be solved via efficient interior-point algorithms. A numerical example is presented to illustrate the feasibility and advantages of the proposed design scheme.

关键词： Parameter-dependent Lyapunov functional Distributed delay systems Sliding mode control Robust stabilization Linear matrix inequalities (LMIs)

在线全文

学校读者我要写书评

暂无评论

海洋石油管线结蜡规律的实验研究

钻采工艺 2007年第1期30卷 111-113页

作者：高长虹澳大利亚西澳州珀斯市柯廷科技大学石油工程系

在石油生产和集输的过程中,由于降温作用,石蜡从原油中淅出,并附着在设备和管道内部,限制流量,因而造成产能损失。尤其是在深海采油过程中,降温作用剧烈,结蜡的危害更加严重。结蜡的机理是温差作用下的分子扩散。世界范围内最普遍的清... 详细信息

在石油生产和集输的过程中,由于降温作用,石蜡从原油中淅出,并附着在设备和管道内部,限制流量,因而造成产能损失。尤其是在深海采油过程中,降温作用剧烈,结蜡的危害更加严重。结蜡的机理是温差作用下的分子扩散。世界范围内最普遍的清蜡办法是使用清蜡器(清蜡球),而清蜡频率的确定还是处在摸索阶段。为了优化清蜡频率,准确预测结蜡的速度是必要的。在项目中,利用一台新型设备对一现场的原油进行了结蜡速度的测试。实验结果表明,对于不同尺寸的管道,在既定的温度条件下,该原油流速相同,则结蜡速度相同;而增大剪切力可降低结蜡速度。

关键词：石蜡结蜡海洋管道

在线全文

学校读者我要写书评

暂无评论

影响凝析油气藏采收率的主要因素

新疆石油地质 2000年第6期21卷 491-492页

作者：高长虹中国石化胜利石油管理局胜利采油厂山东东营257051

凝析油气藏有其独特的特点，如开发方式选择不当，会在很大程度上影响采收率。通过室内实验和实例调研。发现，压力保持水平对采收率有决定性的影响，即要想使凝析油气藏获得较高采收率，就必须在开采过程中使油藏压力始终保持在饱和压... 详细信息

凝析油气藏有其独特的特点，如开发方式选择不当，会在很大程度上影响采收率。通过室内实验和实例调研。发现，压力保持水平对采收率有决定性的影响，即要想使凝析油气藏获得较高采收率，就必须在开采过程中使油藏压力始终保持在饱和压力以上。此外，地层伤害、井筒积液和水合物堵塞对凝析油气藏的采收率也有较大的影响，应采取相应措施予以克服。

关键词：凝析油气田开发采收率油层压力饱和压力

在线全文

学校读者我要写书评

暂无评论

液压驱动并联加载机构正弦位置/力幅相控制

农业机械学报 2018年第7期49卷 395-400,362页

作者：高长虹何彪曲智勇丛大成中航工业庆安集团有限公司航空设备研究所西安710077 哈尔滨工业大学机电工程学院哈尔滨150001

液压驱动并联加载机构对试件进行多自由度位置/力加载时,受到液压系统非线性因素和试件耦合作用的影响,其位置和力加载自由度的频宽难以提高,导致正弦位置/力响应信号的幅值衰减和相位滞后。为提高系统对正弦位置/力信号的跟踪精度,提... 详细信息

液压驱动并联加载机构对试件进行多自由度位置/力加载时,受到液压系统非线性因素和试件耦合作用的影响,其位置和力加载自由度的频宽难以提高,导致正弦位置/力响应信号的幅值衰减和相位滞后。为提高系统对正弦位置/力信号的跟踪精度,提出一种改进幅相控制方法。对正弦信号幅值、相位、均值3个特征参数进行评估,将评估后的3个特征参数作为控制变量分别进行控制,给出相应的幅相控制器设计和参数整定方法。实验结果表明,该方法能有效提高正弦位置/力信号的跟踪精度,具有控制结构简单、调节参数少、参数整定方便的特点。

关键词：并联加载机构幅相控制液压系统正弦位置/力信号跟踪精度

骨质疏松椎体爆裂骨折椎体后凸成形术与保守治疗比较

在线全文

学校读者我要写书评

暂无评论

中国矫形外科杂志 2017年第24期25卷 2218-2223页

作者：高长虹张庆国张涛山东大学附属济南市中心医院骨科济南250013

[目的]探讨骨质疏松椎体爆裂骨折椎体内空腔形成后椎体后凸成形术和保守治疗的疗效。[方法]2007年6月~2013年2月对84例无神经症状的骨质疏松椎体爆裂骨折椎体内空腔形成患者分为两组,椎体后凸成形术(PKP)治疗组42例,保守组42例。治疗后6... 详细信息

[目的]探讨骨质疏松椎体爆裂骨折椎体内空腔形成后椎体后凸成形术和保守治疗的疗效。[方法]2007年6月~2013年2月对84例无神经症状的骨质疏松椎体爆裂骨折椎体内空腔形成患者分为两组,椎体后凸成形术(PKP)治疗组42例,保守组42例。治疗后6、12个月评估疼痛程度(VAS),椎体畸形指数,椎体前-后高度比值及其恢复率和活动能力。[结果]PKP组无患者发生感染、肺栓塞等并发症,14例患者轻度骨水泥渗漏,包括6例椎体前、4例椎间盘内、4例椎管内,但均无临床症状。84例随访12~24个月,平均22.1月。术后12个月时,PKP组VAS(0.88±0.59)分,显著低于保守组(2.52±0.83)分(P=0.001);但PKP组活动能力评级高于保守组,两组差异有统计学意义(P=0.002)。此外,PKP组畸形指数(1.41±0.18),显著低于保守组(1.72±0.11)(P<0.001);PKP组椎体前后高度比为(71.96±18.20)%,保守组为(49.94±6.13)%,PKP组椎体高度恢复率为+16.15%,显著高于保守组(-24.28%)(P<0.001)。[结论]与保守治疗比较,经椎弓根椎体后凸成形术治疗骨质疏松椎体爆裂骨折椎体内空腔形成在疼痛缓解、椎体畸形恢复上更加有效。

关键词：骨质疏松椎体爆裂骨折椎体后凸成形术保守治疗