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OPTIMUM CONTROL TO A PARTIALLY CONTROLLED TURBOGENERATOR SHAFT TORSIONAL VIBRATION SYSTEM

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Chinese Journal of Mechanical Engineering 2002年第1期15卷 66-68页

作者： Hao Zhiyong Gao Wenzhi School of Mechanical Engineering，tianjin University，tianjin 300072，China School of Mechanical Engineering Tianjin University 天津 300072

The optimal control to a partially controlled turbogenerator shaft torsionalvibration system is investigated. The principle of input feedforward control is presented to achievethe minimum of the average vibration energy in a system, and the optimal control matrix of thesystem is derived. A turbogenerator shaft system is taken as an example to simulate the optimalcontrol process of the torsional vibration. Results from this simulation indicate that the vibrationcan be effectively controlled by a partial control strategy.

关键词： Optimal control Partially controlled system Torsional vibration Turbogenerator

Probabilistic Distribution of Ice Forces on a Solitary Pile in the Liaodong Bay

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China Ocean Engineering 1996年第1期11卷 65-70页

作者： Wang Yonggang Shi Qingzeng Postgraduate, tianjin University, tianjin 300072 Professor, Dept. of Ocean Eng. and Naval Arch., tianjin Univ., tianjin 300072 tianjin University Tianjin 300072 Dept. of Ocean Eng. and Naval Arch. Tianjin Univ. Tianjin 300072

The level ice thickness and compressive strength at the four measuring stations in the Liaodong Bay are inferred according to the hydrologic and meteorologic data there, then the yearly extreme ice forces on a solitary pile are calculated by the use of appropriate formula of ice forces and its probabilistic distribution is determined. Generally, the yearly extreme ice force follows Weibull distribution best as compared with Normal, Lognormal, and Extreme Value I distribution. On the other hand, the short-term distribution of ice forces on a solitary pile is obtained from the model experiment data analysis: It does not refuse Extreme Value I distribution.

关键词： solitary pile ice forces yearly extreme value distribution short-term distribution

四川省升钟水库水体富营养变化趋势分析及处理对策

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四川水利 2024年第4期45卷 92-94,138页

作者：蒲菊梅王天金四川省南充水文水资源勘测中心四川南充637000

升钟水库是国家划定的重要水功能区,位于一级水功能区西河保留区的源头。通过近年来对升钟水库水质监测数据进行富营养化评价分析,发现有由中营养向轻度富营养发展的趋势,针对变化趋势和实际监测情况,分析富营养化发展的原因并提出处理... 详细信息

升钟水库是国家划定的重要水功能区,位于一级水功能区西河保留区的源头。通过近年来对升钟水库水质监测数据进行富营养化评价分析,发现有由中营养向轻度富营养发展的趋势,针对变化趋势和实际监测情况,分析富营养化发展的原因并提出处理对策。

关键词：富营养变化趋势分析原因处理对策

疏勒河灌区不同灌溉方式下不同作物水效益分析

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智慧农业导刊 2024年第9期4卷 29-33页

作者：尚天津张建新甘肃省疏勒河流域水资源利用中心甘肃玉门735211

在疏勒河流域智慧水利建设过程中,按照数字孪生灌区农田作物精准化灌溉的要求,为掌握不同灌溉模式下不同作物水效益,该文通过对疏勒河灌区广泛种植的小麦、玉米和食葵进行水效益分析研究并得出相应的数据。试验表明,滴灌模式下不同作物... 详细信息

在疏勒河流域智慧水利建设过程中,按照数字孪生灌区农田作物精准化灌溉的要求,为掌握不同灌溉模式下不同作物水效益,该文通过对疏勒河灌区广泛种植的小麦、玉米和食葵进行水效益分析研究并得出相应的数据。试验表明,滴灌模式下不同作物的水效益最高,灌区传统的漫灌方式水效益最低,已无法适应现代化灌区的建设要求。因此,在疏勒河灌区大力推广节水灌溉技术,是建设现代化灌区的必然要求。

关键词：灌溉方式节水效益经济效益现代化灌区智慧水利

Transition prediction of a hypersonic boundary layer over a cone at small angle of attack——with the improvement of e^N method

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Science China(Physics,Mechanics & Astronomy) 2009年第1期52卷 115-123页

作者： SU CaiHong1 & ZHOU Heng1,2 1 Department of Mechanics, tianjin University, tianjin 300072, China 2 Liu-Hui Center of Applied Mathematics, Nankai University and tianjin University, tianjin 300072, China 1. Department of Mechanics Tianjin University Tianjin 300072 China 2. Liu-Hui Center of Applied Mathematics Nankai University and Tianjin University Tianjin 300072 China

The problem of transition prediction for hypersonic boundary layers over a sharp cone has been studied in this work. The Mach number of the oncoming flow is 6, the cone half-angle is 5°, and the angle of attack is 1°. The conventional e N method is used, but the transition location so obtained is obviously incorrect. The reason is that in the conventional method, only the amplifying waves are taken into account, while in fact, for different meridians the decay processes of the disturbances before they begin to grow are different. Based on our own previous work, new interpretation and essential improvement for the e N method are proposed. Not only the amplification process but also the decay process is considered. The location, where by linear stability theory, the amplitude of disturbance wave is amplified from its initial small value to 1%, is considered to be the transition location. The new result for transition prediction thus obtained is found to be fairly satisfactory. It is also indicated that for the calculation of base flow, boundary layer equations can be used for a small angle of attack. Its computational cost is much smaller than those for DNS.

关键词： angle of attack cone transition eN method

Low-temperature optical spectra and zero-phonon transition of color centers in γ-rayed lithium fluoride crystals

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Chinese Journal of Lasers 1993年第5期B2卷 59-63页

作者： Honggen Gu (Department of Physics, tianjin University, tianjin 300072,China) tianjin Univ Tianjin China

The zero-phonon lines on R2, R~+, N1and R′2centers and some new narrow lines have been observed in bivalent-metal-doped and air-grown LiF crystals irradiated by γ-ray in the temperature range of 9.5—130K. The spect... 详细信息

关键词： low-temperature spectra zero-phonon transition color-centers in LiF2

Transition prediction for supersonic and hypersonic boundary layers on a cone with angle of attack

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Science China(Physics,Mechanics & Astronomy) 2009年第8期52卷 1223-1232页

作者： SU CaiHong1 & ZHOU Heng1,2 1 Department of Mechanics,tianjin University,tianjin 300072,China 2 Liu-Hui Center of Applied Mathematics,Nankai University and tianjin University,tianjin 300072,China Department of Mechanics Tianjin University Tianjin 300072 China Liu-Hui Center of Applied Mathematics Nankai University and Tianjin University Tianjin 300072 China

Transition prediction for boundary layers has always been one of the urgent problems waiting for a solution for the development of aero-space technology,yet there is no reliable and effective method due to the complexity of the *** eN method has been regarded as an effective method for the transition prediction of boundary ***,it heavily relies on experiment or *** in cases with three-dimensional base flow,for instance,the boundary layer on a cone with angle of attack,the result of its application is not *** authors have found its cause and proposed the method for its improvement,which did yield the fairly satisfactory result for a given test case,and also did not rely so much on experiment or ***,before people can really apply this method to practical problems,more test cases have to be *** this paper,more test cases for the application of the improved eN method to problems of transition prediction of supersonic and hypersonic boundary layers on cones with angle of attack will be *** results are compared with those obtained by experiments and/or direct numerical simulations,confirming that the improved eN method is effective and *** also find that there may be more than one ZARF for each meridian plane,and which one should be chosen for the eN method has been clarified.

关键词： angle of attack cone boundary layer transition eN method

Structural modulation of Cd(Ⅱ) supramolecular frameworks with a versatile 2,4-dipyridyl-type building block and different dicarboxylate ligands

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Science China Chemistry 2009年第9期52卷 1470-1478,1523-1524页

作者： LI ChengPeng, YU Qian & DU Miao College of Chemistry and Life Science, tianjin Key Laboratory of Structure and Performance for Functional Molecule, tianjin Normal University, tianjin 300387, China College of Chemistry and Life Science Tianjin Key Laboratory of Structure and Performance for Functional Molecule Tianjin Normal University Tianjin China

A series of Cd(Ⅱ) coordination complexes with an elongated 2,4-dipyridyl-type building block trans-1-(2-pyridyl)-2-(4-pyridyl)ethylene (bpe) and different dicarboxylate ligands have been presented. Generally, bpe shows the unidentate coordination mode and serves as the terminal pendant, whereas the dicarboxylate ligands display various binding fashions to interlink the metal centers to form 1-D comb-like chain, ribbon, and fishbone arrays, as well as 2-D 44 and 4.82 layered networks. Notably, the bpe building block is also involved in secondary interactions such as hydrogen bonding and aromatic stacking to construct the resulting supramolecular architectures. Thermal stability of these complexes has been studied by TG-DTA technique.

关键词： crystal engineering coordination supramolecular framework Cd(Ⅱ) complex secondary interaction thermal stability

β→α Transformation of γ-Phase in Sintered WC-Co Cemented Carbides

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Journal of Materials Science & Technology 1996年第5期12卷 398-400页

作者： Shourong LIU (tianjin Institute of Hard Alloy tianjin 300222, China)Yi LIU (Shandong University Jinan 250100, China) SHANDONG UNIV JINAN 250100PEOPLES R CHINA

Varying the morphology and the structure of γ-phase (Co-base Co-W-C solid solution) by means of altering the cooling rate and the preparing method of liquid sintered WC-Co cemented carbides samples, the mechanism of fcc→hcp transformation of γ-phase in WC-Co alloy has been explored. The results show that, the cooling rate is an important affecting factor on fcc→hcp transformation of γ-phase and the fcc→hcp transformation is mainly a diffusive type when cooling WC-Co samples above room temperature

关键词： WC Co Phase in Sintered WC-Co Cemented Carbides Transformation of