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基于变论域模糊PID控制的注塑机开合模定位系统 被引量:13
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作者 于斌 李素玲 郑薇 《山东理工大学学报(自然科学版)》 CAS 2017年第3期60-64,69,共6页
为防止注塑机在开合模过程中,由于开合模位置不精确造成的合模力不足和机械对冲现象,提高注塑机开合模位置的精确度,在传统的模糊控制基础上提出变论域的算法改进;用伺服技术改进注塑机的开合模控制机构,并利用Simulink工具对其系统进... 为防止注塑机在开合模过程中,由于开合模位置不精确造成的合模力不足和机械对冲现象,提高注塑机开合模位置的精确度,在传统的模糊控制基础上提出变论域的算法改进;用伺服技术改进注塑机的开合模控制机构,并利用Simulink工具对其系统进行仿真实验.结果表明:该控制方法能有效减小系统误差和防止干扰,并且更短的调节时间保证了系统的跟随性能,有利于快速注塑机的推广应用. 展开更多
关键词 注塑机 开合过程 闭环液压控制 变论域模糊控制
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垂直提升开启式拱桥动力特性分析 被引量:1
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作者 孙昊 庞浩然 +1 位作者 张超 郭小权 《建筑科学与工程学报》 CAS 北大核心 2018年第1期86-92,共7页
首先介绍了垂直提升开启式拱桥的基本组成以及开启与闭合过程的实现,然后运用有限元软件MIDAS/Civil对一座垂直提升开启式钢管混凝土人行拱桥进行了动力特性的数值分析,研究了桥梁闭合状态和开启状态下的自振频率和振型,分析了拱肋刚度... 首先介绍了垂直提升开启式拱桥的基本组成以及开启与闭合过程的实现,然后运用有限元软件MIDAS/Civil对一座垂直提升开启式钢管混凝土人行拱桥进行了动力特性的数值分析,研究了桥梁闭合状态和开启状态下的自振频率和振型,分析了拱肋刚度和横撑数量对该类型桥梁自振特性的影响。结果表明:桥梁开启前后的振动频率在第5阶时差别稍大,其他各阶自振频率几乎相同,振型也基本相同;开启后开启段主梁的纵向和竖向振幅较大;增大拱肋的刚度,结构自振频率增大,有利于提高拱桥的整体稳定性;横撑数量的多少对拱肋的耦合振动影响最大;所得结论可以为同类型桥梁的设计和抗震分析提供参考。 展开更多
关键词 拱桥 垂直提升开启桥 开合过程 动力特性 拱肋刚度 横撑
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Role of Metacognition in Mathematical Problem Solving Process of Permutations and Combinations--Basic Study for CAI Software Development 被引量:1
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作者 Atsuo Murata Yukio Ohta 《Computer Technology and Application》 2013年第6期296-306,共11页
When solving a mathematical problem, we sometimes encounter a situation where we can not reach a correct answer in spite of acquiring knowledge and formula necessary for the solution. The reason can be attributed to t... When solving a mathematical problem, we sometimes encounter a situation where we can not reach a correct answer in spite of acquiring knowledge and formula necessary for the solution. The reason can be attributed to the lack in metacognitive abilities. Metacognitive abilities consist of comparing the difficulty of problem with own ability, proper plan of solution process, and conscious monitoring and control of solution process. The role and importance of metacognitive ability in mathematical problem solving of permutations and combinations was explored. Participants were required to solve five practical problems related to permutations and combinations. For each problem, the solution process was divided into: (1) understanding (recognition) of mathematical problem; (2) plan of solution; (3) execution of solution. Participants were also required to rate the anticipation whether they could solve it or not, and to rate the confidence of their own answer. According to the total score of five problems, the participants were categorized into the group of the high test score and the group of the low test score. As a result, at the plan and the execution processes, statistically significant differences were detected between the high and the low score groups. As for the rating on the anticipation of result and the confidence of own answer, no significant differences were found between both groups. Moreover, the relationship between the score of plan process and the score of execution process was statistically correlated. In other words, the more proper the plan process was conducted, the more proper solution the participants reached. In such a way, the importance of metacognitive ability in the solving process, especially the plan ability, was suggested. 展开更多
关键词 Permutation and combination problem METACOGNITION understanding plan EXECUTION CAI (computer assistedinstruction).
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Decay Process of Quantum Open System at Finite Temperatures
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作者 肖骁 高一波 《Communications in Theoretical Physics》 SCIE CAS CSCD 2012年第8期251-254,共4页
Starting from the formal solution to the Heisenberg equation, we revisit an universal model for a quantum open system with a harmonic oscillator linearly coupled to a boson bath. The analysis of the decay process for ... Starting from the formal solution to the Heisenberg equation, we revisit an universal model for a quantum open system with a harmonic oscillator linearly coupled to a boson bath. The analysis of the decay process for a Fock state and a coherent state demonstrate that this method is very useful in dealing with the problems in decay process of the open system. For finite temperatures, the calculations of the reduced density matrix and the mean excitation number for the open system show that an initiaJ coherent state will evolve into a temperature-dependant coherent state after tracing over the bath variables. Also in short-time limit, a temperature-dependant effective Hamiltonian for the open system characterizes the decay process of the open system. 展开更多
关键词 quantum open system decay process temperature-dependant effective Hamiltonian
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