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LARGE AMPLITUDE FREE VIBRATIONS OF LAMINATED COMPOSITE PLATES

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Acta Mechanica Solida Sinica 2000年第1期13卷 75-80页

作者： Wang Haowen gao zheng zheng Zhaochang Department of Aircraft Nanjing University of Aeronautics and AstronauticsNanjing 210016China Department of Engineering Mechanics Tsinghua UniversityBejing 100084China

This paper deals with large amplitude free flexural vibrations of laminated composite plates using a 9-node Heterosis degenerated isoparametric quadrilateral element, including the effects of transverse shear and rotary inertia. The nonlinear dynamic equations of the plates are formulated in von Karman's sense. Amplitude-frequency relationships are obtained through dynamic response history using; the Newmark numerical integration scheme. Detailed numerical results based on various parameters are presented for orthotropic laminated plates with different boundary conditions. The rectangular anti-symmetric cross-ply plates show the softening type of nonlinearity for initial small amplitudes. The displacement amplitudes decrease and nonlinear frequencies increase with the increment of time.

关键词： composite plate free vibration

Multi-frequency point supported LLRF front-end for CiADS wide-bandwidth application

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Nuclear Science and Techniques 2020年第3期31卷 66-73页

作者： Qi Chen zheng gao zheng-Long Zhu Zong-Heng Xue Yuan He Xian-Wu Wang Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China

The China initiative Accelerator Driven System,CiADS,physics design adopts 162.5 MHz,325 MHz,and 650 MHz cavities,which are driven by the corresponding radio frequency(RF)power system,requiring frequency translation front-end for the RF *** that application,a general-purpose design front-end prototype has been developed to evaluate the multi-frequency point supported design *** difficult parts to achieve the requirements of the general-purpose design are reasonable device selection and balanced *** a carefully selected low-noise wide-band RF mixer and amplifier to balance the performance of multi-frequency supported down-conversion,specially designed LO distribution net to increase isolation between adjacent channels,and external band-pass filter to realize expected up-conversion frequencies,high maintenance and modular front-end generalpurpose design has been *** of standard parameters show an R2 value of at least 99.991%in the range of-60-10 dBm for linearity,up to 18 dBm for P1dB,and up to 89 dBc for cross talk between adjacent *** phase noise spectrum is lower than 80 dBc in the range of 0-1 MHz;cumulative phase noise is 0.006°;and amplitude and phase stability are 0.022%and 0.034°,respectively.

关键词： Frequency jump RF Front-end LLRF CiADS

Robustness Analysis of Discrete-time Indirect Model Reference Adaptive Control with Normalized Adaptive Laws

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International Journal of Automation and computing 2010年第3期7卷 381-388页

作者： Qing-zheng gao Xue-Jun Xie Department of Physics and Information Engineering Jining University Qufu 273155 PRC School of Electrical Engineering and Automation Xuzhou Normal University Xuzhou 221116 PRC

For a class of discrete-time systems with unmodeled dynamics and bounded disturbance, the design and analysis of robust indirect model reference adaptive control （MRAC） with normalized adaptive law are investigated. The main work includes three parts. Firstly, it is shown that the constructed parameter estimation algorithm not only possesses the same properties as those of traditional estimation algorithms, but also avoids the possibility of division by zero. Secondly, by establishing a relationship between the plant parameter estimate and the controller parameter estimate, some similar properties of the latter are also established. Thirdly, by using the relationship between the normalizing signal and all the signals of the closed-loop system, and some important mathematical tools on discrete-time systems, as in the continuous-time case, a systematic stability and robustness analysis approach to the discrete indirect robust MRAC scheme is developed rigorously.

关键词： Discrete-time systems model reference adaptive control (MRAC) swapping lemmas stability robustness

Selection and thermal physical characteristics analysis of in-situ condition preserved coring lunar rock simulant in extreme environment

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International Journal of Mining Science and Technology 2023年第11期33卷 1411-1424页

作者： Haichun Hao Mingzhong gao Cunbao Li Xuan Wang Yan Wu zheng gao Wen Yu Xuemin Zhou Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization Institute of Deep Earth Sciences and Green EnergyCollege of Civil and Transportation EngineeringShenzhen UniversityShenzhen 518060China Shenzhen Key Laboratory of Deep Underground Engineering Sciences and Green Energy Shenzhen UniversityShenzhen 518060China Center for Lunar and Planetary Sciences Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China

With the increasing scarcity of Earth’s resources and the development of space science and technology,the exploration, development, and utilization of deep space-specific material resources(minerals, water ice, volatile compounds, etc.) are not only important to supplement the resources and reserves on Earth but also provide a material foundation for establishing extraterrestrial research bases. To achieve large depth in-situ condition-preserved coring(ICP-Coring) in the extreme lunar environment, first, lunar rock simulant was selected(SZU-1), which has a material composition, element distribution, and physical and mechanical properties that are approximately equivalent to those of lunar mare basalt. Second, the influence of the lunar-based in-situ environment on the phase, microstructure, and thermal physical properties(specific heat capacity, thermal conductivity, thermal diffusivity, and thermal expansion coefficient)of SZU-1 was explored and compared with the measured lunar rock data. It was found that in an air atmosphere, low temperature has a more pronounced effect on the relative content of olivine than other temperatures, while in a vacuum atmosphere, the relative contents of olivine and anorthite are significantly affected only at temperatures of approximately-20 and 200 ℃. When the vacuum level is less than100 Pa, the contribution of air conduction can be almost neglected, whereas it becomes dominant above this threshold. Additionally, as the testing temperature increases, the surface of SZU-1 exhibits increased microcracking, fracture opening, and unevenness, while the specific heat capacity, thermal conductivity,and thermal expansion coefficient show nonlinear increases. Conversely, the thermal diffusivity exhibits a nonlinear decreasing trend. The relationship between thermal conductivity, thermal diffusivity, and temperature can be effectively described by an exponential function(R^(2)>0.98). The research results are consistent with previous studies

关键词： Lunar-based Lunar rock simulant Extreme environment Thermal physical properties

Characterization of the fracture compressibility and its permeability for shale under the effects of proppant embedment and compaction:A preliminary study

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Petroleum Science 2022年第3期19卷 1125-1138页

作者： Jian-Hua Li Bo-Bo Li Qiao-Yun Cheng zheng gao Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization Institute of Deep Earth Sciences and Green EnergyCollege of Civil and Transportation EngineeringShenzhen UniversityShenzhen518060GuangdongChina Shenzhen Key Laboratory of Deep Underground Engineering Sciences and Green Energy Shenzhen UniversityShenzhen518060GuangdongChina College of Mining Guizhou UniversityGuiyang550025GuizhouChina Guizhou Key Laboratory of Comprehensive Utilization of Non-metallic Mineral Resources Guiyang550025GuizhouChina National&Local Joint Laboratory of Engineering for Effective Utilization of Regional Mineral Resources from Karst Areas Guizhou UniversityGuiyang550025GuizhouChina

Hydraulic fracturing technology plays a key role in improving the recovery rate of shale *** improvement of permeability in relation to hydraulic fracturing depends on changes brought about by the proppant on the fracture structure in *** it is of great significance to describe the microscopic changes during this process by means of an accurate theoretical *** this study,based on the heterogeneity of shale fracture and the compaction and embedment of a proppant,we proposed a permeability model to examine the combined effects of a proppant and stress to describe the change mechanism in ***,changes in fracture width and porosity were considered,and a calculation model of fracture compressibility under proppant compaction and embedment was *** difference from previous studies is that the compressibility and permeability of supported fractures can be further quantified and analyzed by this ***,its rationality was verified by publicly released test *** results show that,the compressive effect of stress and the embedding of proppant both have a negative impact on shale permeability.

关键词： Shale Fracture compressibility Permeability Hydraulic fracturing Proppant embedment

Synthesis and properties of novel hole-transporting materials with triphenylamine units

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Chinese Chemical Letters 2012年第2期23卷 141-144页

作者： Wen zheng gao Xiang gao Li Shi Rong Wang Hai Jun Lv School of Chemical Engineering and Technology Tianjin UniversityTianjin 300072China College of Chemical and Pharmaceutical Engineering Hebei University of Science and Technology Shijiazhuang 050018China

Two novel organic hole-transporting materials have been synthesized by combination of triphenylamines（TPA） viaπ-conjugated bonds using Wittig *** structures were characterized by NMR,FT-IR and *** optical,electrochemical and thermal properties of the materials were studied in *** results show that these two compounds have blue emission,proper HOMO levels and high thermal ***,a quantum chemical calculation on electron distribution of the two compounds was performed, which suggests the current synthesized materials would be promising candidates for hole-transporting materials.

关键词： Wittig reaction Triphenylamine Hole-transporting materials Quantum chemical calculation

Negative Photoconductivity Induced by Surface Plasmon Polaritons in the Kretschmann Configuration

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Chinese Physics Letters 2011年第12期28卷 242-244页

作者： zheng Jing-gao SUN Jia-Lin XUE Ping Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics Tsinghua UniversityBeijing 100084

Prism coupling in the Kretschmann configuration is a well-known method for the excitation of surface plasmon polaritons(SPPs)in thin films bounded from one side by a prism and from the other side by *** on the Kretschmann configuration,we experimentally study the transport properties of a silver thin film with a thickness of 55 nm and a width of 500µm undergoing total internal *** observe considerable negative photoconductivity in the film induced by the SPPs excited in this configuration and find that both SPP-electron interactions and SPP-induced heating have contributions to the negative *** believe that the new phenomena,which result from the combination of photonics and electronics,will be useful in relative technical applications and scientific research.

关键词： configuration film Configuration

Removal of Phosphorus From High Phosphorus Iron Ores by Selective HCl Leaching Method

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Journal of Iron and Steel Research International 2011年第5期18卷 1-4,19页

作者： XIA Wen-tang REN zheng-de gao Yi-feng School of Metallurgical and Materials Engineering Chongqing University of Science and Technology Chongqing 401331 China

The selective HCl leaching method was used to remove phosphorus from high phosphorus iron ores. The hydroxyapatite in high phosphorus iron ores was converted into soluble phosphate during the process of HCl leaching. The effects of reaction time,particle size,hydrochloric acid concentration,reaction temperature,liquid-solid ratio and stirring strength on the dephosphorization ratio were studied. The results showed that the dephosphorization ratio can exceed 98% under the conditions of reaction time 30-45 min,particle size 0.147 mm,hydrochloric acid concentration 2.5 mol/L,reaction temperature 25 ℃,liquid-solid ratio 5：1 and stirring strength 5.02-12.76 s-1. After dephosphorization reaction,the content of phosphorus in iron ore complied completely with the requirements of steel production.

关键词： high phosphorus iron ore dephosphorus selective leaching hydrochloric acid dephosphorization ratio

Smoothing methods based on coordinate transformation in a linear space and application in airfoil aerodynamic design optimization

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Science China(Technological Sciences) 2015年第2期58卷 297-306页

作者： WANG Chao gao zheng Hong HUANG Jiang Tao ZHAO Ke LI Jing National Key Laboratory of Aerodynamic Design and Research Northwestern Polytechnical University China Aerodynamics Research & Development Center

In detailed aerodynamic design optimization,a large number of design variables in geometry parameterization are required to provide sufficient flexibility and obtain the potential optimum ***,with the increasing number of design variables,it becomes difficult to maintain the smoothness on the surface which consequently makes the optimization process progressively *** this paper,smoothing methods based on B-spline functions are studied to improve the smoothness and design *** wavelet smoothing method and the least square smoothing method are developed through coordinate transformation in a linear space constructed by B-spline basis *** these two methods,smoothing is achieved by a mapping from the linear space to itself such that the design space remains unchanged.A design example is presented where aerodynamic optimization of a supercritical airfoil is conducted with smoothing methods included in the optimization *** results from the design example confirm that these two smoothing methods can greatly improve quality and efficiency compared with the existing conventional non-smoothing method.

关键词： smoothness linear space B-spline functions coordinate transformation wavelet least square aerodynamicoptimization