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不稳定型心绞痛合并糖尿病患者经皮冠状动脉介入治疗后应对方式分析
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作者 罗曲博 张园园 丁苗苗 《四川解剖学杂志》 2022年第1期45-47,共3页
目的:分析不稳定型心绞痛合并糖尿病患者经皮冠状动脉介入治疗(PCI)后应对方式的影响因素.方法:选取2018年2月至2020年6月于本院接受PCI治疗的80例不稳定型心绞痛合并糖尿病患者作为研究对象.采用医学方式应对问卷(MCMQ)评估患者应对方... 目的:分析不稳定型心绞痛合并糖尿病患者经皮冠状动脉介入治疗(PCI)后应对方式的影响因素.方法:选取2018年2月至2020年6月于本院接受PCI治疗的80例不稳定型心绞痛合并糖尿病患者作为研究对象.采用医学方式应对问卷(MCMQ)评估患者应对方式.根据PCI后患者应对方式,分别纳入消极组(n=27)与积极组(n=53).统计所有患者临床资料,将可能的影响因素纳入分析,找出不稳定型心绞痛合并糖尿病患者PCI后应对方式的影响因素.结果:80例不稳定性心绞痛合并糖尿病患者消极应对27例(33.75%),积极应对53例(66.25%).消极应对组文化程度、医疗费用支付方式占比高于积极应对组,差异有统计学意义(P<0.05).经Logistic回归分析结果显示,文化程度为高中及以下、医疗费用支付方式为自费是不稳定性心绞痛合并糖尿病患者PCI后消极应对的影响因素(OR=3.042、4.235,P=0.023、0.004).结论:不稳定性心绞痛合并糖尿病患者PCI后消极应对受高中及以下文化程度、医疗费用支付方式因素的影响. 展开更多
关键词 心绞痛 不稳性型 糖尿病 经皮冠状动脉介入治疗 应对方式
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阿托伐他汀治疗不稳定型心绞痛的临床疗效研究
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作者 徐丹 李刚 《中国医药指南》 2015年第9期125-126,共2页
目的观察阿托伐他汀对不稳定型心绞痛的疗效。方法确诊的不稳型性心绞痛患者40例,随机分为治疗组和对照组,每组20例。两组常规治疗相同,治疗组患者加用阿托伐他汀,观察治疗4个月心绞痛患者的临床症状、记录12导联心电图ST段压低数值及... 目的观察阿托伐他汀对不稳定型心绞痛的疗效。方法确诊的不稳型性心绞痛患者40例,随机分为治疗组和对照组,每组20例。两组常规治疗相同,治疗组患者加用阿托伐他汀,观察治疗4个月心绞痛患者的临床症状、记录12导联心电图ST段压低数值及血脂的变化。结果治疗4个月阿托伐他汀组(治疗组)胆固醇、低密度脂蛋白胆固醇明显下降(P<0.05),心绞痛症状及心电图均明显改善(P<0.05)有显著性差异,明显减少了心脏事件发生。结论阿托伐他汀治疗不稳定型心绞痛疗效显著。 展开更多
关键词 阿托伐他汀 不稳心绞痛 心电图
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Preliminary Studies on the Effect of Photoperiod and Temperature on Male Fertility of a Cytoplasmic Male Sterile Line in Wheat 被引量:2
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作者 王丰青 巍荷 +1 位作者 何觉民 何仪 《Agricultural Science & Technology》 CAS 2008年第2期85-89,共5页
[Objective] The study aimed to reveal the effect of photoperiod and temperature on male fertility of cytoplasmic male sterile line Vtai911289a in wheat and discuss the mechanism of male fertility alteration. [ Method ... [Objective] The study aimed to reveal the effect of photoperiod and temperature on male fertility of cytoplasmic male sterile line Vtai911289a in wheat and discuss the mechanism of male fertility alteration. [ Method ] The sowing-date tests and designed conditions were conducted during 2003 -2005. [ Result] Fertility of Vtai911289a, could alter under specific photoperiod and temperature conditions. Temperature is one of the main factors influencing male fertility of the male sterile lines. Vtai911289a, showed stable sterility under the condition of the mean of daily temperature at fertility sensitive stage lower than 19℃ and presented partial fertility when the mean of daily temperature at fertility sensitive stage lower than 20 - 22℃. Photoperiod to some extent affects the male fertility of Vtai911289a, long-day condition is helpful for the male fertility of the sterile line. [ Conclusion] The application of photoperiod temperature-sensitive cytoplasmic male sterile line in production has a higher safety than that of temperature sensitive sterile line. 展开更多
关键词 Temperature PHOTOPERIOD Cytoplasmic male sterile line Male fertility
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Stable ischemic heart disease in the older adults 被引量:5
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作者 Xuming DAI Jan Busby-Whitehead +1 位作者 Daniel E Forman Karen P Alexander 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2016年第2期109-114,共6页
1 Introduction Ischemic heart disease is caused by atherosclerotic and/or thrombotic obstruction of coronary arteries. Clinical spec- trum of ischemic heart disease expands from asymptomatic atherosclerosis of corona... 1 Introduction Ischemic heart disease is caused by atherosclerotic and/or thrombotic obstruction of coronary arteries. Clinical spec- trum of ischemic heart disease expands from asymptomatic atherosclerosis of coronary arteries to acute coronary syn- dromes (ACS) including unstable angina, acute myocardial infarction (non-ST elevation myocardial infarction and ST elevation myocardial infarction). Stable ischemic heart dis- ease (SIHD) refers to patients with known or suspected SIHD who have no recent or acute changes in their symp- tomatic status, suggesting no active thrombotic process is underway. 展开更多
关键词 AGING Coronary artery disease Older adults Risk assessment Stable ischemic heart disease
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Multiple-Relaxation-Time Lattice Boltzmann Approach to Richtmyer-Meshkov Instability 被引量:1
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作者 陈锋 许爱国 +1 位作者 张广财 李英骏 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第2期325-334,共10页
The aims of the present paper are twofold. At first, we further study the Multiple-Relaxation-Time (MRT) Lattice Boltzmann (LB) model proposed in [Europhys. Lett. 90 (2010) 54003]. We discuss the reason why the ... The aims of the present paper are twofold. At first, we further study the Multiple-Relaxation-Time (MRT) Lattice Boltzmann (LB) model proposed in [Europhys. Lett. 90 (2010) 54003]. We discuss the reason why the Gram Schmidt orthogonalization procedure is not needed in the construction of transformation matrix M; point out a reason why the Kataoka-Tsutahara model [Phys. Rev. E 69 (2004) 035701(R)] is only valid in subsonic flows. The yon Neumann stability analysis is performed. Secondly, we carry out a preliminary quantitative study on the Richtmyer- Meshkov instability using the proposed MRT LB model. When a shock wave travels from a light medium to a heavy one, the simulated growth rate is in qualitative agreement with the perturbation model by Zhang-Sohn. It is about half of the predicted value by the impulsive model and is closer to the experimental result. When the shock wave travels from a heavy medium to a light one, our simulation results are also consistent with physical analysis. 展开更多
关键词 lattice Boltzmann method Richtmyer-Meshkov instability compressible flows multiple- relaxation-time von Neumann stability analysis
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Gas-Fluid and Fluid-Solid Phase Instability for Restricted Primitive Model
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作者 GUO Yuan-Yuan CHEN Xiao-Song 《Communications in Theoretical Physics》 SCIE CAS CSCD 2009年第8期356-360,共5页
By considering the fluctuation of grand potential f~ around equilibrium with respect to small one-particle density fluctuations δpα(r→), the phase instability of restricted primitive model (RPM) of ionic system... By considering the fluctuation of grand potential f~ around equilibrium with respect to small one-particle density fluctuations δpα(r→), the phase instability of restricted primitive model (RPM) of ionic systems is investigated. We use the integral equation theory to calculate the direct correlation functions in the reference hypernetted chain approximation and obtain the spinodai line of RPM. Our anaiysis explicitly indicates that the gas-fluid phase instability is induced by k = 0 fluctuation mode, while the fluid-solid phase instability is related to k ≠ 0 fluctuation modes. The spinodai line is qualitatively consistent with the result of computer simulations by others. 展开更多
关键词 phase instability restricted primitive model the reference hypernetted chain approximation
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Low-speed instability analysis for hydraulic motor based on nonlinear dynamics 被引量:4
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作者 LIN Rong-chuan WEI Sha-sha YUAN Xiao-ling 《Journal of Coal Science & Engineering(China)》 2010年第3期328-332,共5页
A nonlinear dynamics model and a mathematical expression were set up to investigatethe mechanism and conditions of vibration creep acceleration.The model showsthat hydraulic spring and nonlinear friction are major fac... A nonlinear dynamics model and a mathematical expression were set up to investigatethe mechanism and conditions of vibration creep acceleration.The model showsthat hydraulic spring and nonlinear friction are major factors that can affect low-speed instability.The mathematic model was established to obtain the change rule of speed andinstantaneous acceleration of the hydraulic motor.Then, Matlab was used to simulate theeffect of nonlinear friction force and hydraulic motor parameters such as coefficient of leakand compression ratio, etc., under low speed.Finally, some measures were proposed toimprove the low-speed stability of the hydraulic motor. 展开更多
关键词 hydraulic motor nonlinear dynamics hydraulic spring vibration creep accel- eration computer simulation
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Dynamic Radiographic Analysis of Sympathetic Cervical Spondylosis Instability 被引量:13
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作者 Jun Qian Ye Tian Gui-xing Qiu Jian-hua Hu 《Chinese Medical Sciences Journal》 CAS CSCD 2009年第1期46-49,共4页
Objective To investigate the correlation between subaxial cervical spine instability and cervical spondylotic sympathetic symptoms as well as the difference of cervical spondylotic subaxial instability between male an... Objective To investigate the correlation between subaxial cervical spine instability and cervical spondylotic sympathetic symptoms as well as the difference of cervical spondylotic subaxial instability between male and female patients. Methods We analyzed retrospectively 318 surgical cases of cervical spondylosis treated at Department of Orthopedic Surgery of Peking Union Medical College Hospital between July 2003 and December 2007. All cases were divided into group A without sympathetic symptoms (n=284) and group B with sympathetic symptoms (n=34). Angular and horizontal translation values between two adjacent vertebral bodies from C2 to C7 were measured separately on hyperflexion and hyperextension lateral cervical spine radiographs. Fisher's exact test was used to evaluate the correlation between subaxial cervical instability and sympathetic symptoms. Intragroup correlation between patient gender and subaxial cervical instability was also evaluated. Results Subaxial instability incidences in groups A and B were 21.8% (62/284) and 55.9% (19/34), respectively. Statistical analysis indicated a definite correlation between subaxial cervical instability and sympathetic symptoms (P=0.000). Among patients without sympathetic symptoms, subaxial instability incidences were 21.4% (37/173) in males and 22.5% (25/111) in females, respectively (P=0.883). While among patients with sympathetic symptoms, subaxial instability incidences were 27.3% (3/11) in males and 69.6% (16/23) in females, respectively, indicating significant difference (P=0.030). Subaxial instability was most commonly seen at C4-C5 intervertebral space in sympathetic cervical spondylosis patients. Conclusions High correlation exists between subaxial cervical spine instability and cervical spondylotic sympathetic symptoms, especially in female patients. Hyperextension and hyperflexion radiographs of cervical spine are important to assess sympathetic cervical spondylotic subaxial instability. 展开更多
关键词 subaxial cervical spine instability SYMPATHETIC cervical spondylosis
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Impacts of NBTI/PBTI on power gated SRAM
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作者 黄平 邢座程 《Journal of Central South University》 SCIE EI CAS 2013年第5期1298-1306,共9页
A signal probability and activity probability (SPAP) model was proposed firstly, to estimate the impacts of the negative bias temperature instability (NBTI) and positive bias temperature instability (PBTI) on power ga... A signal probability and activity probability (SPAP) model was proposed firstly, to estimate the impacts of the negative bias temperature instability (NBTI) and positive bias temperature instability (PBTI) on power gated static random access memory (SRAM). The experiment results show that PBTI has significant influence on the read and write operations of SRAM with power gating, and it deteriorates the NBTI effects and results in a up to 39.38% static noise margin reduction and a 35.7% write margin degradation together with NBTI after 106 s working time. Then, a circuit level simulation was used to verify the assumption of the SPAP model, and finally the statistic data of CPU2000 benchmarks show that the proposed model has a reduction of 3.85% for estimation of the SNM degradation after 106 s working time compared with previous work. 展开更多
关键词 negative bias temperature instability (NBTI) positive bias temperature instability (PBTI) static random access memory(SRAM) power gating
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R-Parity Violation Effects on b_1 → bχ_1~0 in Minimal SupersymmetricStandard Model
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作者 ZHANGRen-You MAWen-Gan +2 位作者 JIANGYi HOUHong-Sheng SUNYan-Bin 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第2期257-267,共11页
We investigate in detail the effects of R-parity lepton number violation onthe decay b_1 → bχ_1~0 in the R-parity violating minimal supersymmetric standard model (R_p-MSSM)under the present experimental constraints ... We investigate in detail the effects of R-parity lepton number violation onthe decay b_1 → bχ_1~0 in the R-parity violating minimal supersymmetric standard model (R_p-MSSM)under the present experimental constraints on R_p parameters. In our numerical calculations weconsider two cases of input parameters of the squark and slepton sectors, M_(squark) 【 M_(slepton)and M_(squark) 】 M_(slepton), for comparison. The results show that the relative R-parity violatingcorrection is not very sensitive to the mass of the lightest neutralino bχ_1~0 the degenerateR-parity violating coupling parameter λ′_2 but strongly depends on M_(squark), M_(slepton) tan βand tie degenerate R-parity violating coupling parameter λ′_1. The relative correction is about -4~ 3% and can exceed -6% in some region of parameter space. Therefore, precise experiment analyseson the decay b_1 → bχ_1~0 may provide a probe of the R-parity violation. 展开更多
关键词 minimal supersymmetric standard model R-parity violation
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Application of gravity inversion focused in Changbai Mountain 被引量:1
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作者 LI Qiuchen WU Yangang 《Global Geology》 2014年第1期62-66,共5页
Focusing inversion is accomplished by the iterative of abnormal source to make the image gradually focused. It can better reflect the underground geological geometry and physical parameters. The model experiments in t... Focusing inversion is accomplished by the iterative of abnormal source to make the image gradually focused. It can better reflect the underground geological geometry and physical parameters. The model experiments in the study show that gravity focusing inversion allows inversion image stabilization and polymerization,which solves the multiple solutions and instability of inversion and so on. The method is applied to measured gravity data processing of certain region of Changbai Mountain,compared to Euler deconvolution,the results show that the method for determining the horizontal position and depth of underground anomalies has good efforts. 展开更多
关键词 focusing inversion gravity inversion Changbai Mountain
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Infrequent microsatellite instability mutator phenotype in Chinese hepatocellular carcinomas
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作者 方丽 房殿春 +2 位作者 汪荣泉 杨仕明 吴凯 《Journal of Medical Colleges of PLA(China)》 CAS 2003年第6期341-344,354,共5页
Objective: In order to elucidate the molecular mechanisms that might be responsible for hepatocarcinogenesis, we examined microsatellite instability (MSI), mismatch repair gene hMLH1 mutation and methylation in hepato... Objective: In order to elucidate the molecular mechanisms that might be responsible for hepatocarcinogenesis, we examined microsatellite instability (MSI), mismatch repair gene hMLH1 mutation and methylation in hepatocellular carcinoma. Methods: Fifty-two cases of surgically resected sporadic hepatocellular carcinoma (HCC) were studied. hMLH1 mutation was examined by two-dimensional electrophoresis and DNA sequencing; hMLH1 methylation was determined by methylation-specific PCR(MSP); and MSI at BAT26 was analyzed by PCR-based methods. Results: MSI at BAT26 was found in 3 of 52 cases (5.8%) of the tumors analyzed. No hMLH1 mutation or hypermethylation was found in these 52 cancerous tissues. No correlation existed between MSI and clinico-pathological characteristics of the patients. Conclusion: Our results suggest that MSI at BAT26 is rarely associated with carcinogenesis of chinese HCC. The genesis of sporadic HCC may occur in an alternative pathway that is probably different from MSI pathway. 展开更多
关键词 hepatocellular carcinoma hMLH1 mutation and methylation microsatellite instability
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On Relative Stability in 4-Dimensional Duck Solution 被引量:1
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作者 Kiyoyuki Tchizawa 《Journal of Mathematics and System Science》 2012年第9期558-563,共6页
This paper gives the existence of a relatively stable duck solution in a slow-fast system in R2+2 with an invariant manifold. The slow-fast system in R2+: has a 2-dimensional slow vector field and a 2-dimensional f... This paper gives the existence of a relatively stable duck solution in a slow-fast system in R2+2 with an invariant manifold. The slow-fast system in R2+: has a 2-dimensional slow vector field and a 2-dimensional fast vector field. The fast vector field restricts a feasible region of the slow vector field strictly. In the case of the slow-fast system in R2+1 , that is, the fast vector field is l-dimension, it is classified according to its sign, because it gives only negative(-), positive(+) or zero sign. Then it is attractive, repulsive or stationary. On the other hand, in R2~2 , the fast vector field has combinatorial cases. It causes a complex state to analyze the system. First, we introduce a local model near the pseudo singular point on which we classify the fast vector field attractive(-,-), attractive-repulsive(-,+) or repulsive(+,+), simply as possible. We prove the existence of a 4-dimensional duck solution in the local model. Secondarily, we assume that the slow-fast system has an invariant manifold near the pseudo singular point. When the invariant manifold has a homoclinic point near the pseudo singular point, we show that the slow-fast sytem has a 4-dimensional duck solution having a relatively stable region. 展开更多
关键词 Slow-fast system singular perturbation BIFURCATION nonstandard analysis.
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Extraversion, emotional instability, and self-reported exercise: The mediating effects of approach-avoidance achievement goals
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作者 Marc Lochbaum Kylee Litchfield +1 位作者 Leslie Podlog Rafer Lutz 《Journal of Sport and Health Science》 SCIE 2013年第3期176-183,共8页
Background: Understanding leisure time physical inactivity is a priority in study sought to address this priority by examining whether the extraversion mediated through Elliot's (1999) 2 x 2 achievement goals. Wes... Background: Understanding leisure time physical inactivity is a priority in study sought to address this priority by examining whether the extraversion mediated through Elliot's (1999) 2 x 2 achievement goals. Westernized nations where participation rates are low. The present and emotional instability to leisure time exercise relationships were Methods: Participants were 116 female and 97 male volunteers from a Southwestern community (mean age = 37.21 years, range 24-69) who completed measures of extraversion, emotional instability, approach-avoidance achievement goals, and 7-day recall of leisure-time exercise. Multiple mediation models (Preacher and Hayes, 2008) were run to specifically examine our hypotheses. Results: The mastery-approach goal mediated the relationship from extraversion to overall exercise and strenuous intensity exercise. Results indicated emotional instability had direct effects on overall and strenuous leisure time exercise while also having significant (p 〈 0.05) indirect mediation paths through the performance-approach and avoidance goals. The extraversion and emotional instability models accounted from 15.89% to 29.82% of variance in the various self-reported exercise measures. Conclusion: The results suggest the promotion of leisure-time exercise would be improved in the studied personalities by manipulation of achievement goals. Copyright @ 2012, Shanghai University of Sport. Production and hosting by Elsevier B.V. All rights reserved. 展开更多
关键词 Achievement goals Big five MEDIATION Physical activity
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A Finite Element Model for the Instability Analysis of Flexible Pipes Tensile Armor Wires
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作者 Gabriel Gonzalez Jose Renato Mendes de Sousa Luis Volnei Sudati Sagrilo 《Journal of Mechanics Engineering and Automation》 2017年第3期165-170,共6页
The instability of the tensile armor wire of flexible pipes is a failure mode associated with deep and ultra-deep water applications. Real compressive forces acting on the pipe are necessary to trigger this process. T... The instability of the tensile armor wire of flexible pipes is a failure mode associated with deep and ultra-deep water applications. Real compressive forces acting on the pipe are necessary to trigger this process. The loss of stability may be divided into two distinct processes, according to the main direction of the wire's displacement: radial or lateral instability. This study aims at proposing a numerical tool for predicting lateral and radial critical buckling loads for the tensile armor wires of flexible pipes. A simple finite element model, based on springs and beams elements, was developed in ABAQUS~ to deal with this problem in an efficient and reliable manner. A parametric study was conducted concerning the behavior of the critical load when the laying angle, the initial curvature and the total pipe length are varied. The results were consistent with previously published literature data and analytical expressions, proving its applicability to pipe engineering projects. It also has the advantage of approaching the problem three-dimensionally, which allows further modelling modifications, such as including friction effects. 展开更多
关键词 Unbonded flexible pipes INSTABILITY finte element modeling.
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Numerical predictions and stability analysis of cavitating draft tube vortices at high head in a model Francis turbine 被引量:2
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作者 ZUO ZhiGang LIU ShuHong +1 位作者 LIU DeMin QIN DaQing 《Science China(Technological Sciences)》 SCIE EI CAS 2014年第11期2106-2114,共9页
Draft tube vortex is one of the main causes of hydraulic instability in hydraulic reaction turbines,in particular Francis turbines.A method of cavitation calculations was proposed to predict the pressure fluctuations ... Draft tube vortex is one of the main causes of hydraulic instability in hydraulic reaction turbines,in particular Francis turbines.A method of cavitation calculations was proposed to predict the pressure fluctuations induced by draft tube vortices in a model Francis turbine,by solving RANS equations with RNG k-turbulence model and ZGB cavitation model,with modified turbulence viscosity.Three cases with different flow rates at high head were studied.In the study case of part load,two modes of revolutions with the same rotating direction,revolution around the axis of the draft tube cone,and revolution around the core of the vortex rope,can be recognized.The elliptical shaped vortex rope causes anisotropic characteristics of pressure fluctuations around the centerline of the draft tube cone.By analyzing the phase angles of the pressure fluctuations,the role of the vortex rope as an exciter in the oscillating case can be recognized.An analysis of Batchelor instability,i.e.instability in q-vortex like flow structure,has been carried out on the draft tube vortices in these three cases.It can be concluded that the trajectory for study case with part load lies in the region of absolute instability(AI),and it lies in the region of convective instability(CI)for study case with design flow rate.Trajectory for study case with over load lies in the AI region at the inlet of the draft tube,and enters CI region near the end of the elbow. 展开更多
关键词 draft tube vortices pressure fluctuations Francis turbine CAVITATION Batchelor instability
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Stability control of steer by wire system based on μ synthesis robust control 被引量:5
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作者 WANG ChunYan DENG Ke +2 位作者 ZHAO WanZhong ZHOU Guan ZHOU Dong 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2017年第1期16-26,共11页
The uncertainty influences may result in performance deterioration and instability to the steer by wire(SBW) system. Thus, it must make the control system keep robust stability from uncertainty, and have good robustne... The uncertainty influences may result in performance deterioration and instability to the steer by wire(SBW) system. Thus, it must make the control system keep robust stability from uncertainty, and have good robustness. In order to effectively restrain the interference and improve steering stability, this paper presents a μ synthesis robust controller based on SBW system, which considers the effect of model uncertainty and external disturbance on the system dynamics. Taking the ideal yaw rate tracking, interference suppression and excellent robustness as the control objectives, the μ synthesis robust controller is designed using linear fractional transformation theory to deal with the uncertainty. Then, it is testified through time domain and robustness simulation analysis. Simulation results show that the proposed controller can not only ensure robustness and robust stability of the system quite well, but improve handling stability of the vehicle effectively. The results of this study provide certain theoretical basis for the research and application of SBW system. 展开更多
关键词 VEHICLE steer by wire μ analysis and synthesis stability control ROBUSTNESS
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Exhaustive Classification of the Invariant Solutions for a Specific Nonlinear Model Describing Near Planar and Marginally Long-Wave Unstable Interfaces for Phase Transition
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作者 Fatemeh Ahangari 《Communications in Theoretical Physics》 SCIE CAS CSCD 2018年第5期477-505,共29页
Problems of thermodynamic phase transition originate inherently in solidification, combustion and various other significant fields. If the transition region among two locally stable phases is adequately narrow, the dy... Problems of thermodynamic phase transition originate inherently in solidification, combustion and various other significant fields. If the transition region among two locally stable phases is adequately narrow, the dynamics can be modeled by an interface motion. This paper is devoted to exhaustive analysis of the invariant solutions for a modified Kuramoto-Sivashinsky equation in two spatial and one temporal dimensions is presented. This nonlinear partial differential equation asymptotically characterizes near planar interfaces, which are marginally long-wave unstable. For this purpose, by applying the classical symmetry method for this model the classical symmetry operators are attained.Moreover, the structure of the Lie algebra of symmetries is discussed and the optimal system of subalgebras, which yields the preliminary classification of group invariant solutions is constructed. Mainly, the Lie invariants corresponding to the infinitesimal symmetry generators as well as associated similarity reduced equations are also pointed out. Furthermore,the nonclassical symmetries of this nonlinear PDE are also comprehensively investigated. 展开更多
关键词 phase transition modified Kuramoto-Sivashinsky ((2D) MKS) equation SYMMETRIES optimal system invariant solutions
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Phase-field modeling of epitaxial growth with the Ehrlich-Schwoebel barrier: Model validation and application
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作者 DONG Xiang Lei XING Hui +4 位作者 SHA Sha CHEN Chang Le NIU Li Wei WANG Jian Yuan JIN Ke Xin 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2015年第4期753-762,共10页
In this paper,we introduce different forms of mobility into a quantitative phase-field model to produce arbitrary Ehrlich-Schwoebel(ES)effects.Convergence studies were carried out in the one-side step-flow model,which... In this paper,we introduce different forms of mobility into a quantitative phase-field model to produce arbitrary Ehrlich-Schwoebel(ES)effects.Convergence studies were carried out in the one-side step-flow model,which showed that the original mobility not only induces the ES effect,but also leads to larger numerical instability with increase of the step width.Thus,another modified form of the ES barrier is proposed,and is found to be more suitable for large-scale simulations.Model applications were performed on the wedding-cake structure,coarsening and coalescence of islands and spiral growth.The results show that the ES barrier exhibits more significant kinetic effects at the larger deposition rates by limiting motions of atoms on upper steps,leading to aggregation on the top layers,as well as the roughening of growing surfaces. 展开更多
关键词 epitaxial growth phase-field method Ehrlich-Schwoebel barrier KINETICS INTERFACIAL
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Stability and Hopf bifurcation for a logistic SIR model with a stage -- Structure 被引量:2
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作者 Hong Yang 《International Journal of Biomathematics》 2016年第1期243-264,共22页
A SIR model of epidemiological dynamics with stage-structure and a type of nonlinear incidence rate is considered under the assumption that the susceptible individual satisfy the logistic equation. The global attracti... A SIR model of epidemiological dynamics with stage-structure and a type of nonlinear incidence rate is considered under the assumption that the susceptible individual satisfy the logistic equation. The global attractivity of the model is studied using Lyapunov functions and LaSalle's invariance principle. By the uniform persistence theories, the permanence of the system and the existence of the positive equilibrium are obtained. Moreover, by the normal form theory and the center manifold presented by Hassard, a stability and Hopf bifurcation analysis of the system around positive equilibrium from a local perspective are performed. Numerical simulation is carried out to illustrate our results. 展开更多
关键词 EPIDEMIOLOGICAL STAGE-STRUCTURE nonlinear incidence rate logistic growth Hopf bifurcation.
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