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Mining Science and Technology 2009年第5期19卷 592-598页

作者： LUO yi cheng Jian-wei Department of Mining Engineering West Virginia University Morgantown WV USA

The distribution of the final surface subsidence basin induced by longwall operations in inclined coal seam could be significantly different from that in flat coal seam and demands special prediction methods. Though many empirical prediction methods have been developed, these methods are inflexible for varying geological and mining conditions. An influence function method has been developed to take the advantage of its fundamentally sound nature and flexibility. In developing this method, significant modifications have been made to the original Knothe function to produce an asymmetrical influence function. The empirical equations for final subsidence parameters derived from US subsidence data and Chinese empirical values have been incorpo- rated into the mathematical models to improve the prediction accuracy. A corresponding computer program is developed. A number of subsidence cases for longwall mining operations in coal seams with varying inclination angles have been used to demonstrate the applicability of the developed subsidence prediction model.

关键词： subsidence prediction influence function method inclined coal seam longwall mining

Additional symmetries of constrained CKP and BKP hierarchies

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Science China Mathematics 2011年第2期54卷 257-268页

作者： TIAN KeLei HE JingSong cheng JiPeng cheng yi Department of Mathematics University of Science and Technology of China Hefei 230026 China Department of Mathematics Ningbo University Ningbo 315211 China

The additional symmetries of the constrained CKP (cCKP) and BKP (cBKP) hierarchies are given by their actions on the Lax operators, and their actions on the eigenfunction and adjoint eigenfunction {Φ i , Ψ i } are presented explicitly. Furthermore, we show that acting on the space of the wave operator, *k forms new centerless W cC 1+∞ and W cB 1+∞ -subalgebra of centerless W 1+∞ respectively. In order to define above symmetry flows *k of the cCKP and cBKP hierarchies, two vital operators Y k are introduced to revise the additional symmetry flows of the CKP and BKP hierarchies.

关键词： constrained CKP hierarchy constrained BKP hierarchy additional symmetry

Vanadium(V) Complexes Containing Unsymmetrical N-Heterocyclic Carbene Ligands: Highly Efficient Synthesis and Catalytic Behavior towards Ethylene/Propylene Copolymerization

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Chinese Journal of Polymer Science 2024年第1期42卷 32-41,I0006页

作者： yi-Cong Wang Hui Zhat Pei-yi cheng Shu Zhang Xiang-Wei Liu yi-Xian Wu State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBejing 100029China

The highly efficient method has been developed for the synthesis of NHC·VOCl_(3) containing symmetrical or unsymmetrical Nheterocyclic carbene(NHC) ligands by the transmetallation reaction of NHC·AgCl with VOCl_(3).The total isolated yield of VOCl_(3)[1,3-(2,4,6-Me_(3)C_(6)H_(2))_(2)(NCH=)_(2)C:](V4') reached 86% by transmetallation reaction,which is much higher than that(48%) by direct coordination *** methodology has also been used to synthesize the novel vanadium complexes containing unsymmetrical NHC ligands of VOCl_(3)[PhCH_(2)NCH=CHNR)C:](V5',R=2,4,6-Me_(3)C_(6)H_(2);V6',R=2,4-Me_(2)-6-Ph-C_(6)H_(2);V7',R=2,6-^(i)Pr_(2)-C_(6)H_(3)) with high yield,which could not be obtained by direct coordination *** catalytic activity and copolymerization ability would be improved by introducing unsymmetrical NHC ligands due to their less steric bulky *** vanadium complex V5' containing unsymmetrical NHC ligand exhibits higher catalytic activity(3.7×10^(5)g_(copolymer)·mol^(-1) of V·h^(-1)) than that of V4' containing symmetrical NHC ***,the higher propylene incorporation ratio(45.6 mol%) in the copolymers of ethylene with propylene could be obtained by using V5' than that(39.9%) by using V4'.The results would provide a highly efficient strategy for the synthesis of early transition metal complexes containing versitile NHC ligands,affording the catalyst with both high catalytic activity and copolymerization ability for the synthesis of high performance polyolefin elastomers.

关键词： Vanadium complex N-heterocyclic carbene ligand Transmetallation reaction Copolymerization of ethylene with propylene

Low complexity reconfigurable architecture for the 5/3 and 9/7 discrete wavelet transform

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Journal of Systems Engineering and Electronics 2006年第2期17卷 303-308页

作者： Xiong cheng yi Tian Jinwen Liu Jian Coll. of Electronic Information Engineering South Center Univ. for Nationalities Wuhan 430074 P.R. China Inst. of Pattern Recognition & Artificial Intelligence Key Lab. of Education Ministry for Image Processing and Intelligent Control Huazhong Univ. of Science & Technology Wuhan 430074 P.R. China

Efficient reconfigurable VLSI architecture for 1-D 5/3 and 9/7 wavelet transforms adopted in JPEG2000 proposal, based on lifting scheme is proposed. The embedded decimation technique based on fold and time multiplexing, as well as embedded boundary data extension technique, is adopted to optimize the design of the architecture. These reduce significantly the required numbers of the multipliers, adders and registers, as well as the amount of accessing external memory, and lead to decrease efficiently the hardware cost and power consumption of the design. The architecture is designed to generate an output per clock cycle, and the detailed component and the approximation of the input signal are available alternately. Experimental simulation and comparison results are presented, which demonstrate that the proposed architecture has lower hardware complexity, thus it is adapted for embedded applications. The presented architecture is simple, regular and scalable, and well suited for VLSI implementation.

关键词： VLSI discrete wavelet transform lifting scheme embedded decimation reeonfigurable.

Binary Nonlinearization of the Nonlinear Schr?dinger Equation Under an Implicit Symmetry Constraint

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Acta Mathematicae Applicatae Sinica 2014年第2期30卷 379-388页

作者： Jing YU Jing-song HE yi cheng School of Science Hangzhou Dianzi University Department of Mathematics University of Science and Technology of China School of Science Ningbo University

By modifying the procedure of binary nonlinearization for the AKNS spectral problem and its adjoint spectral problem under an implicit symmetry constraint, we obtain a finite dimensional system from the Lax pair of th... 详细信息

关键词： an implicit symmetry constraint binary nonlinearization AKNS system completely integrable Hamiltonian system

Acoustic skin meta-muffler

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Science China(Physics,Mechanics & Astronomy) 2021年第9期64卷 87-92页

作者： Yong-Xin Gao yi cheng Bin Liang Yong Li Jing Yang Jian-Chun cheng Key Laboratory of Modern Acoustics Ministry of EducationInstitute of AcousticsDepartment of PhysicsNanjing UniversityNanjing 210093China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China Institute of Acoustics School of Physics Science and EngineeringTongji UniversityShanghai 200092China

The effective elimination of sound energy traveling in open ducts is critical in acoustics,with considerable potential in diverse applications ranging from duct noise control to exhaust system ***,previous absorber mechanisms are bulky or have limited ventilation or unsatisfactory absorption *** propose and experimentally demonstrate the concept of meta-mufflers capable of quasi-perfectly absorbing airborne sound propagating in an open duct while minimizing the influence on airflow because of its vanishing *** mechanism uses coupling among asymmetric metasurfaces to achieve impedance match and subsequent high absorption in a subwavelength scale,which is explained analytically and validated *** proposed meta-muffler features an uncomplicated design,high attenuation efficiency,and a thickness of nearly two orders of magnitude of wavelength,ensuring the free pass of other ***,our design offers the flexibility of tuning and extending working bandwidth by hybridization of weak *** performance of the proposed muffler is verified via experiments,which correlate excellently with theoretical *** realization of meta-mufflers opens a route to novel acoustic absorbers and could have far-reaching implications in a plethora of important scenarios calling for both perfect sound absorption and open acoustic paths.

关键词： acoustic metamaterial ultrathin sound absorber coupling effect broadband high absorption

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The research of DPA attacks against AES implementations

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The Journal of China Universities of Posts and Telecommunications 2008年第4期15卷 101-106页

作者： HAN Yu ZOU Xue-cheng LIU Zheng-lin CHEN yi-cheng Department of Electronic Science and Technology Huazhong University of Science and Technology Wuhan 430074 China

This article examines vulnerabilities to power analysis attacks between software and hardware implementations of cryptographic algorithms. Representative platforms including an Atmel 89S8252 8-bit processor and a 0.25 um 1.8 v standard cell circuit are proposed to implement the advance encryption standard （AES）. A simulation-based experimental environment is built to acquire power data, and single-bit differential power analysis （DPA）, and multi-bit DPA and correlation power analysis （CPA） attacks are conducted on two implementations respectively. The experimental results show that the hardware implementation has less data-dependent power leakages to resist power attacks. Furthermore, an improved DPA approach is proposed. It adopts hamming distance of intermediate results as power model and arranges plaintext inputs to differentiate power traces to the maximal probability. Compared with the original power attacks, our improved DPA performs a successful attack on AES hardware implementations with acceptable power measurements and fewer computations.

关键词： AES implementation side-channel leakage DPA CPA power model power trace

High-order breather,M-kink lump and semi-rational solutions of potential Kadomtsev-Petviashvili equation

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Communications in Theoretical Physics 2021年第3期73卷 28-35页

作者： Yulei Cao yi cheng Jingsong He yiren Chen School of Mathematical Sciences University of Science and Technology of ChinaHefeiAnhui 230026China Institute for Advanced Study Shenzhen UniversityShenzhenGuangdong 518060China College of Mathematics and Statistics Shenzhen UniversityShenzhenGuangdong 518060China

N-kink soliton and high-order synchronized breather solutions for potential Kadomtsev-Petviashvili equation are derived by means of the Hirota bilinear method,and the limit process of high-order synchronized breathers are ***,M-lump solutions are also presented by taking the long wave ***,a family of semi-rational solutions with elastic collision are generated by taking a long-wave limit of only a part of exponential functions,their interaction behaviors are shown by three-dimensional plots and contour plots.

关键词： PKP equation bilinear method breather Af-kink lump semi-rational solution

Damage detection of a thin plate using modal curvature via macrostrain measurement

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Earthquake Engineering and Engineering Vibration 2019年第2期18卷 409-424页

作者： Ting Yu Hsu yi cheng Shih Quang-Vinh Pham Department of Civil and Construction Engineering Taiwan University of Science and Technology Chung-Shan Institute of Science and Technology

Plate structures are employed as important structural components in many engineering applications. Hence, assessing the structural conditions of in-service plate structures is critical to monitoring global structural health. Modal curvature-based damage detection techniques have recently garnered considerable attention from the research community, and have become a promising vibration-based structural health monitoring solution. However, computing errors arise when calculating modal curvatures from lateral mode shapes, which result from unavoidable measurement errors in the mode shapes as identified from lateral vibration signals; this makes curvature-based algorithms that use a lateral measurement only theoretically feasible, but practically infeasible. Therefore, in this study, long-gauge fiber Bragg grating strain sensors are employed to obtain a modal curvature without a numerical differentiation procedure in order to circumvent the computing errors. Several damage indices based on modal curvatures that were developed to locate beam damage are employed. Both numerical and experimental studies are performed to validate the proposed approach. However, although previous studies have reported relative success with the application of these damage indices on a simple beam, only one damage index demonstrated the capability to locate damage when the stiffness of the local region changed near the sensor.

关键词： macro strain long gauge modal curvature plate damage detection

Investigation on the performance of a helico-axial multiphase pump under slug flow

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Petroleum Science 2022年第4期19卷 1812-1824页

作者： Jia-Xiang Zhang Jin-Ya Zhang Ye Zhou Zi-yi-yi cheng Guang-Da Cao College of Mechanical and Transportation Engineering China University of PetroleumBejing102249China Beijing Key Laboratory of Process Fluid Filtration and Separation China University of PetroleumBejing102249China China Institute of Water Resources and Hydropower Research Beijing100044China

The helico-axial multiphase pump is often used for gas-liquid mixture transportation in offshore oilfields,and slug flow is the main reason for the unstable operation of the *** for slug flow condition,a self-designed three-stage multiphase pump is set to the object to perform unsteady simulations and fluid-structure interaction calculations,and the inlet gas void fraction(IGVF)is set from 20%to 80%.The results show that affected by the flow from the slug,the gas-liquid two-phase flow pattern in the multiphase pump changes sharply,resulting in severe fluctuations in the differential pressure,spindle torque and deformation of the multiphase *** gas-phase enters the first-impeller along the suction blade surface when affected by Taylor bubbles,while the second and third-stage impellers gas-phases are in the form of small air masses flow into the impeller along the pressure blade *** deformation trend of impeller torque,differential pressure and the main pump spindle is similar to that of trigonometric function,while the fluctuation of torque is more intense,and the shape variable of spindle increases with the inflow of liquid plug,and the maximum deformation amount increases by10.9%at high GVF relative to IGVF.

关键词： Multiphase pump Slug flow Gas void fraction(GVF) Hydraulic performance Fluid-structure interaction