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whirl SSA:一种基于高级中间表示的优化结构

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小型微型计算机系统 2012年第2期33卷 210-214页

作者：杨克峤李健胡益斌许铝才复旦大学并行处理研究所上海201203

中间表示对编译器的性能、效率和可扩展性都起着决定性作用.Open64编译器采用一种树型结构的中间表示whirl,能表示各种高级控制流结构,但不能显式的提供数据流信息.本文基于whirl对SSA(Static Single Assignment)进行扩展,提出了一个新... 详细信息

中间表示对编译器的性能、效率和可扩展性都起着决定性作用.Open64编译器采用一种树型结构的中间表示whirl,能表示各种高级控制流结构,但不能显式的提供数据流信息.本文基于whirl对SSA(Static Single Assignment)进行扩展,提出了一个新的优化结构whirl *** SSA通过将SSA信息标注在whirl节点上,显式的为数据流分析提供使用-定义(UD)信息.相比于传统的数据流信息构建方法,whirl SSA提供了更精确、有效的数据流信息.本文讨论了whirl SSA的设计与实现和基于whirl SSA的优化.

关键词：中间表示 SSA whirl 编译边界检测消除

BWDSP SIMD指令的whirl中间表示生成研究

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中国集成电路 2015年第3期24卷 30-35页

作者：王昊王向前中国电子科技集团公司第三十八研究所安徽合肥230088

whirl是Open64采用的一种通用的中间表示,支持多种高级语言和多种目标机。Open64的后端优化工作都是基于whirl设计的。BWDSP是一款支持SIMD指令的数字信号处理器,SIMD指令能够提高该处理器的指令并行性。SIMD优化也需要产生whirl中间表... 详细信息

whirl是Open64采用的一种通用的中间表示,支持多种高级语言和多种目标机。Open64的后端优化工作都是基于whirl设计的。BWDSP是一款支持SIMD指令的数字信号处理器,SIMD指令能够提高该处理器的指令并行性。SIMD优化也需要产生whirl中间表示,本文对如何产生BWDSP SIMD指令的whirl中间表示进行了研究,并在BWDSP的编译器OCC上得以实现。

关键词：数字信号处理器单指令多数据 whirl 中间表示

On physical models in ***'s three papers on drill string whirling and torsional vibrations

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Petroleum 2020年第1期6卷 31-34页

作者： Zifeng Li Chaoyue Zhang Guangming Song Petroleum Engineering Institute Yanshan UniversityQinhuangdao066004China

This paper introduces physical models of drill string whirling and torsional vibrations and analyses the physical models in ***'s three papers on drill string whirling and torsional vibrations:“***,***,Drill string bit whirl simulation with the use of frictional and nonholonomic models,Journal of Vibration and Acoustics 138(1)(2016)011021”,“***,***,Nonholonomic dynamics of drill string bit whirling in a deep bore-hole,J Multi-body Dynamics 227(3)(2013)234–244”and“***,SN Hudoliy,***,Simulation of torsion relaxation auto-oscillations of drill string bit with viscous and coulombic friction moment models,J Multi-body Dynamics 225(2011)139–152”.This work finds that the physical models described in these three papers are clearly incorrect.

关键词： Drill string Vibration Lateral Torsion whirl

Dynamic Stability Study of Static Gas Bearing for Small Cryogenic Turbo-Expander

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Plasma Science and Technology 2011年第4期13卷 506-512页

作者：王学敏庄明张启勇李姗姗付豹 Institute of Plasma Physics Chinese Academy of Sciences

An experimental method is presented to analyze the dynamic stability of the gas bearing for small cryogenic turbo-expanders. The rotation imbalance response and the shape of the rotor orbit were obtained for different speeds up to 110,000 rpm, and the critical speed of the rotor-bearing system was determined by a Bode diagram. An FFT signal analytical method was applied to identify the resonance frequency, and the waterfall plot was presented. During the whole process of speeding up to the designed speed of 110,000 rpm, the rotor-bearing works stably with no whirl instability, which is validated in a waterfall plot. Also, the tested rotor-bearing model was analyzed theoretically. It was proved that the experimental results were highly consistent with those of theoretical calculations. Thus the experimental method proposed here to analyze the dynamic stability of the gas bearing is feasible.

关键词： rotor-bearing stability imbalance whirl

Wind-induced instabilities and monitoring of wind turbine

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Earthquake Engineering and Engineering Vibration 2019年第2期18卷 475-485页

作者： Isaac Wait Zhaohui (Joey) Yang Gang Chen Benjamin Still College of IT & Engineering Marshall University Department of Civil Engineering University of Alaska Anchorage

This paper presents real-time monitoring data and analysis results of the non-stationary vibrations of an operational wind turbine. The advanced time-frequency spectrum analysis reveals varied non-stationary vibrations with timevarying frequencies, which are correlated with certain system natural modes characterized by finite element analysis. Under the effects of strong wind load, the wind turbine system exhibits certain resonances due to blade passing excitations. The system also exhibits certain instabilities due to the coupling of the tower bending modes and blade flapwise mode with blade passing excitations under the variation of wind speed. An analytical model is used to elaborate the non-stationary and instability phenomena observed in experimental results. The properties of the nonlinear instabilities are evaluated by using Lyapunov exponent estimation.

关键词： wind turbine condition monitoring non-stationary vibrations instabilities whirl modes warm permafrost

APPLICATION OF MECHANIZED MATHEMATICS TO ROTOR DYNAMICS

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Applied Mathematics and Mechanics(English Edition) 2002年第9期23卷 1045-1053页

作者：胡超王岩王立国黄文虎 Department of Aerospace Engineering and Mechanics Harbin Institute of TechnologyHarbin 150001P R China

Based on the mechanized mathematics and WU Wen-tsun elimination method, using oil film forces of short-bearing model and Muszynska's dynamic model, the dynamical behavior of rotor-beating system and its stability of motion are investigated. As example, the concept of Wu characteristic set and Maple software, whirl parameters of short-bearing model, which is usually solved by the numerical method, are analyzed. At the same time, stability of zero solution of Jeftcott rotor whirl equation and stability of self-excited vibration are studied. The conditions of stable motion are obtained by using theory of nonlinear vibration.

关键词： Wu-elimination method characteristic set stability of motion rotor-bearing system whirl

Interesting and unusual cases of chronic abdominal pain-intermittent gastric volvulus

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Open Journal of Gastroenterology 2012年第4期2卷 200-205页

作者： Sivasankaran Vadivel Kumaran Thangavelu Pugazhendhi Mohammed Ali Department of Medical Gastroenterology Madras Medical College & Government Rajiv Gandhi Hospital Chennai India Medgemmc@***

Objective: Intermittent gastric volvulus is a rare disease that requires high index of suspicion for diagnosis and treatment. The incidence and prevalence is unknown, may be due to under reporting or under diagnosis. Gastric volvulus may be transient producing few symptoms. The Borchardt’s Triad may be present only during an acute presentation. Common symptoms may mislead to diagnose a nonsurgical disease if an evaluation is not done, keeping in mind a possibility of gastric volvulus, even if a UGI scopy is normal. Cases may be submerged in the community being undiagnosed. Case Series: CASE 1: 21 yrs old male with intermittent abdominal pain for 1(1/2) yrs with marfanoid habitus, MVP and a normal UGI scopy. BMS revealed an Organo-Axial Volvulus and ligament laxity per-operatively. CASE 2: 65 yrs old diabetic female with vomiting and abdominal pain for 3 months and left sided pneumonitis. UGI scopy showed twisted gastric folds immediately below OGJ and inability to visualise antrum. BMS revealed mixed volvulus with paraesophageal herniation of distal stomach. Per-operatively there was laxity of ligaments with omental content alone within the diaphragmatic rent. Posterior retrocolic sub-mucosal gastrojejunostomy(pexy) was done for all cases. Conclusion: Gastric volvulus should be thought of in a case of chronic intermittent abdominal pain with normal baseline evaluation. A Chest X-ray and BMS should be done, at the time of symptoms.

关键词： Intermittent Gastric Volvulus Chronic Abdominal Pain Barium Meal Series whirl Sign

Diagnosis and Treatment of the Vibration Fault of a Gas Turbine 6300kW

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Journal of Harbin Institute of Technology(New Series) 1994年第1期1卷 30-33页

作者：汪光明李邦宜邓樱王莉

ＤｉａｇｎｏｓｉｓａｎｄＴｒｅａｔｍｅｎｔｏｆｔｈｅＶｉｂｒａｔｉｏｎＦａｕｌｔｏｆａＧａｓＴｕｒｂｉｎｅ６３００ｋＷＷＡＮＧＧｕａｎｇｍｉｎｇＬＩＢａｎｇｙｉＤＥＮＧＹｉｎｇＷＡＮＧＬｉ（汪光明）（李邦宜）（邓樱）... 详细信息

ＤｉａｇｎｏｓｉｓａｎｄＴｒｅａｔｍｅｎｔｏｆｔｈｅＶｉｂｒａｔｉｏｎＦａｕｌｔｏｆａＧａｓＴｕｒｂｉｎｅ６３００ｋＷＷＡＮＧＧｕａｎｇｍｉｎｇＬＩＢａｎｇｙｉＤＥＮＧＹｉｎｇＷＡＮＧＬｉ（汪光明）（李邦宜）（邓樱）（王莉）（Ｄｅｐｔ．ｏｆＰｏｗｅｒ...

关键词： ss: Trouble shooting gas turbine vibration tight force of central rod oil whirl

Nonlinear Vibration of Rotor Rubbing Stator Caused by Initial Perturbation

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Tsinghua Science and Technology 2001年第4期6卷 335-339页

作者：张小章隆锦胜李正光 Department of Engineering Physics Tsinghua University Beijing 100084 China Department of Mechanical Engineering Massachusetts Institute of Teclmology Cambridge MA 02139 USA

The vibration of a rotor rubbing a stator caused by an initial perturbation was studied analytically. The analytical model consists of a simple disc shaft rotor and a fixed stator. The perturbation is an instantaneous change of the radial velocity when the rotor is operating in its normal steady state. The analysis showed that the rotor may continue rubbing the stator for small clearance, even if the initial perturbation no longer exists. For the interest of engineering applications, we investigated various rotating speeds, perturbation amplitudes and clearances between the rotor and the stator. Various friction coefficients on the contact surface were also considered. The graphical results can be used for the design of rotating machines. 

关键词： rotor stator rubbing whirl nonlinear phenomenon