钢管混凝土组合框架结构体系抗震性能的增量动力分析法

基于有限元软件ABAQUS用户材料模型子程序二次开发技术,建立了钢管混凝土组合框架体系的数值模拟模型,该模型得到了以往研究者完成的钢管混凝土构件及组合框架结构低周往复荷载试验结果的验证。分别基于非线性纤维梁单元及分层壳单元模拟梁柱构件及楼板,用增量动力分析(IDA)方法对某9层钢管混凝土空间框架结构的抗震性能进行了研究,对某一地震动下结构由弹性阶段到屈服再到塑性阶段过程中的性能点、层间位移角、结构顶层谱加速度时程响应、框架塑性铰出铰顺序及基底剪力时程曲线进行了判定,为进一步评估钢管混凝土空间框架结构的抗震性能提供参考。     

Interconnection and damping assignment and Euler-Lagrange passivity-based control of photovoltaic/battery hybrid power source for stand-alone applicatlons

A DC hybrid power source composed of photovoltaic cells as the main power source,Li-ion battery storage as the secondary power source,and power electronic interface,is modeled based on port-controlled ...     

迭代判断分析法和神经元网络法用于粒子鉴别的比较

研究了在北京正负电子对撞机（BEPC）的BES谱仪实验中利用迭代判断分析法（IDA）和神经元网络法（NN）进行e,υ,π粒子的鉴别。在完全相同的条件下给出了两种方法在0.2GeV/c到1.66GeV/c动量区间对3尖粒子的鉴别效率与本底水平。虽然用于训练的样本本身具有非均匀的动量谱,但两种方法的检验结果给出的粒子选择效率在整个动量区间仍然具有相当均匀的分布。结果表明,在这一应用中NN法要好于IDA法。对这两种方法各自的特色和适用条件进行了讨论。     

亚氨基二乙酸-氯化钠-水三元体系溶解度模型

根据电解质溶液理论,对Nass和P inho等人提出的氨基酸在NaC l水溶液中溶解度的UNIFAC模型特点进行了分析比较。采用Chen等人提出的电解质型三元体系NRTL活度系数关联方程,结合考虑Born项和P itzer-Debye-Hückel项对基团间长程相互作用力的贡献,在简化基础上,建立了计算IDA-NaC l-H2O三元体系溶解度数学模型。采用该模型对此体系0—60℃范围内的溶解度随温度变化关系进行关联计算,并与实测结果进行对比分析,结果令人满意,二者的平均相对误差为2.93%。按照基团静电作用机制,理论解释了NaC l浓度对IDA溶解度的影响规律。     

PTED框架基于IDA方法失效模式识别

为了进-步研究后张预应力装配混凝土框架(post-tensioned energy dissipating,PTED框架)在不同地震动记录下的失效模式,对该结构进行了增量动力分析(IDA).以OpenSEES软件为平台,建立了四层三跨PTED框架非线性分析模型,选取三条代表性的地震动记录对其进行IDA分析,得到了三种不同的IDA曲线.结果表明:预应力筋提供良好的自复位能力;角钢提供良好的耗能能力;不同地震动记录下,PTED结构呈现三种不同的失效模式.     

酸枣多糖铁药理活性初步研究

目的:评价酸枣多糖铁(ZJSP-Fe(Ⅲ))抗缺铁性贫血作用,为酸枣资源开发利用提供依据。方法:采用紫外、红外、扫描电镜等方式对其形态及微观结构进行表征,采用1,1-二苯基-2-三硝基苯肼(DPPH)自由基、2,2-联氮基双(3-乙基-苯并噻唑啉-6-磺酸)二铵盐(ABTS)自由基以及OH自由基对其清除率进行抗氧化作用研究,对于其体外铁释放率采用人工胃液及肠液进行研究,抗缺铁性贫血作用采取缺铁性贫血大鼠模型进行研究。并比较给药前后大鼠血常规数据及血清中促红细胞生成素(EPO)以及Hepcidin含量,判断其改善IDA大鼠模型的效果。结果:合成的酸枣多糖铁中铁含量可达21.7%,对DPPH·、ABTS+·及·OH清除率的EC₅₀分别为1.47、10.21、0.37 mg/mL,在人工消化液中保持3 h后释铁率可达89.28%,合成的酸枣多糖铁能够显著(p<0.05)增加缺铁性贫血大鼠模型红细胞数量(RBC)、血红蛋白含量(HGB)、红细胞压积(HCT)、EPO、Fe等指标,可显著(p<0.05)降低Hepcidin水平。结论:酸枣多糖铁具有良好的抗氧化活性及体外释铁性能,能够有效改善IDA大鼠模型缺铁症状,有望作为一种新型功能性补铁剂进行继续研究,并需进一步对其抗缺铁性贫血机理进行研究。     

基于IDA和纤维模型的高墩大跨连续刚构桥梁地震反应分析

基于纤维模型的有限元方法,建立了典型高墩大跨连续刚构桥的非线性数值分析模型.采用动力增量分析法,即IDA方法对结构进行了非线性动力时程分析,分别探讨了在纵桥向和横桥向地震作用下高墩连续刚构桥梁结构的破坏规律、最大位移和最大曲率的关系,高阶振型效应对高墩大跨连续刚构桥墩身内力和变形的影响及位移和曲率沿墩高变化的规律.     

Performance evaluation of parallel iterative deepening A on clusters of workstations

In this paper we investigate the performance of distributed heuristic search methods based on a well-known heuristic search algorithm, the iterative deepening A^* (IDA^*). The contribution of this paper includes proposing and assessing a distributed algorithm for IDA^*. The assessment is based on space, time and solution quality that are quantified in terms of several performance parameters such as generated search space and real execution time among others. The experiments are conducted on a cluster computer system consisting of 16 hosts built around a general-purpose network. The objective of this research is to investigate the feasibility of cluster computing as an alternative for hosting applications requiring intensive graph search. The results reveal that cluster computing improves on the performance of IDA^* at a reasonable cost.     

Output-feedback IDA stabilisation of an SMIB system using a TCSC

Interconnection and damping assignment (IDA) passivity-based control (PBC) is currently a well-known viable alternative for solving regulation control problems of a wide class of nonlinear systems. However, a distinctive feature that, in spite of its appearance under several applications, has not been exhaustively exploited, is the flexibility that this technique exhibits for designing output-feedback controllers (OFCs). The purpose of this article is to illustrate this attractive characteristic by approaching the (practically important) case study given by the improvement of the transient stability properties of power systems. The particular system composed by a synchronous generator connected to an infinite bus via a thyristor controlled series capacitor is considered. Two OFCs are presented, one that does not involve the unmeasurable state and another that, although including this state, presents some input-to-state stability properties that allow for establishing a sort of separation principle concerning an observer-based structure for the closed-loop system. The advantages of both controllers are illustrated by numerical simulations when a three-phase short circuit at the generator bus is induced.     

Vibration suppression for mass‐spring‐damper systems with a tuned mass damper using interconnection and damping assignment passivity‐based control

This paper considers a vibration suppression control method using feedback for a mass‐spring‐damper system with a tuned mass damper. For vibration suppression, we adopt the interconnection and damping assignment passivity‐based control, whereby the system is transformed to a system with a skyhook damper with an artificial structure matrix. The feedback law includes no accelerometer signal and uses only information on relative displacements and velocities. The proposed control method can simultaneously suppress the influences of the floor vibration and the disturbance force acting on the main body. A guideline for choosing parameters of the desired system is shown. The proposed method can be easily extended to nonlinear cases, which is demonstrated for a nonlinear‐spring case. We also show the input‐to‐state stability property of closed‐loop systems for linear cases and nonlinear cases. Copyright © 2015 John Wiley & Sons, Ltd.