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脑室持续外引流的压力控制问题──引流管自动控压模式探讨 被引量:3
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作者 王守森 王前 《生物医学工程学杂志》 EI CAS CSCD 北大核心 1997年第2期185-187,共3页
通过流体力学分析,对脑室引流术中脑室压的控制作重新评估。作者认为,计量脑室压的基准手面以外耳道水平为宜;引流管分布模式应不仅能将稳定状态的脑室压控制于生理范围,还能缓冲颅内压的剧烈波动,引流管最高点高度和末端高度均为... 通过流体力学分析,对脑室引流术中脑室压的控制作重新评估。作者认为,计量脑室压的基准手面以外耳道水平为宜;引流管分布模式应不仅能将稳定状态的脑室压控制于生理范围,还能缓冲颅内压的剧烈波动,引流管最高点高度和末端高度均为控制脑室压的重要因素,引流管中段和末端过低均可致颅内低压。本文提出了较理想的引流管分布模式。 展开更多
关键词 脑室外引流 颅内 引流管 自动控压模式
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BOOST变换器不连续导通模式下的混沌现象分析 被引量:1
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作者 苏嘉梁 潘峰 刘勇平 《太原科技大学学报》 2015年第5期347-352,共6页
研究输出电压反馈型Boost DC/DC变换器,构建并推导了不连续导通方式下(即DCM方式)变换器的离散映射模型。基于此数学模型,以倍周期分岔理论分析了变换器的分岔特性。并利用Matlab软件搭建仿真模块,通过仿真验证了离散模型的正确性,并且... 研究输出电压反馈型Boost DC/DC变换器,构建并推导了不连续导通方式下(即DCM方式)变换器的离散映射模型。基于此数学模型,以倍周期分岔理论分析了变换器的分岔特性。并利用Matlab软件搭建仿真模块,通过仿真验证了离散模型的正确性,并且详细给出了变换器从稳定逐步到混沌的全过程。该文的研究具有基础性,为更加深入研究Boost变换器工作时的混沌现象打下基础。 展开更多
关键词 混沌 BOOST变换器 模式 不连续传导模式
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热力学排气工作过程中流体热分层实验研究 被引量:5
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作者 刘展 张晓屿 +2 位作者 张少华 刘欣 厉彦忠 《宇航学报》 EI CAS CSCD 北大核心 2017年第7期743-750,共8页
基于地面热力学排气实验平台,以R123为工质,在初始液位0.595 m、外部漏热800 W的工况下,研究了箱体增压、混合喷射降压、节流制冷以及自然冷却等不同工作过程中箱内流体温度分布。实验结果表明:在增压阶段,箱内流体温度分层发展良好。... 基于地面热力学排气实验平台,以R123为工质,在初始液位0.595 m、外部漏热800 W的工况下,研究了箱体增压、混合喷射降压、节流制冷以及自然冷却等不同工作过程中箱内流体温度分布。实验结果表明:在增压阶段,箱内流体温度分层发展良好。在混合喷射阶段,当循环流量为96 L/h时,热层厚度发展速率为1.57 mm/min;而当循环流量增加到152 L/h时,热层厚度增加率为1.07 mm/min。热分层充分发展大约耗时5.48 h。在节流制冷阶段,液相温度变化基本控制在1.98℃以内,气相最大温降13℃。自然冷却阶段开始15 min后,制冷喷射的影响逐渐消失。在外部空气冷却下,气相温度逐渐趋于顶部温度最低、界面温度最高的线性分布;液相测点则基本上以恒定的速率平行向温度降低方向推进。 展开更多
关键词 低温推进剂 热分层 热力学排气 控压模式
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Loop Compensator Design for DCM Peak-Current-Mode Control DC-DC Buckboost Converter 被引量:1
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作者 J.J. Shieh C.H. Chao 《Journal of Energy and Power Engineering》 2010年第4期30-36,共7页
An analytic closed-form based loop compensator for direct current-direct current (DC-DC) buckboost converter in discontinuous conduction with peak current-mode control is proposed to increase efficiency of the desir... An analytic closed-form based loop compensator for direct current-direct current (DC-DC) buckboost converter in discontinuous conduction with peak current-mode control is proposed to increase efficiency of the desired process through systemization. As a result, the process saves a lot of computation time that can be translated into design cost savings. Finally, the output voltage regulation in the presence of audio susceptibility and output impedance is shown for verifying. 展开更多
关键词 Converter PEAK current mode audio susceptibility output impedance
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Novel consistency control strategy for jet dispensing
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作者 SHEN Ping LI Han-xiong 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第6期1418-1436,共19页
A new consistency control method for jet dispensing is proposed. First, the working parameters, namely, viscosity, supply pressure and supply time, are experimentally investigated. Then, the glue viscosity is approxim... A new consistency control method for jet dispensing is proposed. First, the working parameters, namely, viscosity, supply pressure and supply time, are experimentally investigated. Then, the glue viscosity is approximated by a polynomial model using the least square method. Based on this model and temperatme control implemented using the Dahlin principle, the viscosity of the glue can be maintained at a constant value. Then, the viscosity model of the glue is applied to deriving the droplet mass as the nominal model of the temperature controller. The robustness of the temperature controller is analyzed by applying the small gain theory. The glue supply pressure controller is designed using the consistency control strategy, and the robustness is analyzed. Finall), simulations and experiments are conducted using a jet dispensing control system. The results show that the proposed control strategy can significantly improve the droplet consistency. 展开更多
关键词 jet dispensing consistency control internal model control disturbance rejection jetting valve
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Modelling and Predictive Control of a Buck-Boost DC-DC Converter
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作者 Gianluca Gatto Ignazio Marongiu +2 位作者 Aldo Perfetto Alessandro Serpi Ivan Luigi Spano 《Journal of Energy and Power Engineering》 2012年第8期1276-1283,共8页
A predictive current control algorithm for the Buck-Boost DC-DC converter is presented in this paper. The continuous time model of the system is properly introduced, then, by imposing a proper PWM modulation pattern, ... A predictive current control algorithm for the Buck-Boost DC-DC converter is presented in this paper. The continuous time model of the system is properly introduced, then, by imposing a proper PWM modulation pattern, its discrete time model is achieved. This last one is successfully employed in determining the steady state locus of the Buck-Boost converter, both in CCM (continuous conduction mode) and DCM (discontinuous conduction mode). A novel continuous time equivalent circuit of the converter is introduced too, with the aim of determining a ripple free representation of the state variables of the system, over both transient and steady state operation. Then, a predictive current control algorithm, suitable in both CCM and DCM, is developed and properly checked by means of computer simulations. The corresponding results have highlighted the effectiveness of the proposed modelling and of the predictive control algorithm, both in CCM and DCM. 展开更多
关键词 Equivalent circuits DC-DC power conversion predictive control.
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