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Improved hybrid position/force controller design of a flexible robot manipulator using a sliding observer

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Journal of Systems Engineering and Electronics 2009年第1期20卷 146-158页

作者： Farooq M Wang Daobo Dar n. u Coll. of Automation Engineering Nanjing Univ. of Aeronautics & Astronautics Nanjing 210016 P. R. China Coll. of Mechanical Engineering Univ. of Engineering and Technology Taxila Pakistan

An improved hybrid position/force controller design of a flexible robot manipulator is presented using a sliding observer. The friction between the end effector and the environment is considered and compensated. For systematic reasons the controller is designed taking into consideration the rigid link subsystems and the flexible joints. The proposed control system satisfies the stability of the two subsystems and copes with the uncertainty of robot dynamics. A sliding observer is designed to estimate the time derivative of the torque applied as input to the rigid part of the robot. For the stability of the observer, it is assumed that the uncertainty of the observed system is bounded. A MRAC algorithm is used for the estimation of the friction forces at the contact point between the end effector and the environment. Finally simulation and experimental results are given, to demonstrate the effectiveness of the proposed controller.

关键词： force control sliding control Lyapunov stability robot end effector friction force.

nanoparticle type effects on flexural, interfacial and vibration properties of GFRE composites

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Chinese Journal of Aeronautics 2016年第2期29卷 520-533页

作者： u.A.Khashaba Mechanical Engineering Department Faculty of Engineering King Abdulaziz University

Damping improvement in composite structures via introducing nanofillers generally has remarkable negative effects on the other mechanical properties. Therefore, in the present work, SiC and A1203 nanoparticles＇ infusion effects on the flexural, interracial and vibration properties of epoxy matrix and glass fiber reinforced epoxy （GFR/E） laminates were investigated. unidirectional （uD-GFR/E） and quasi-isotropic （QI-GFR/E） laminates with [0/± 45/90]s and [90/±45/0]s stack- ing sequences were hybridized by the optimum nanoparticles percentages. Results from off-axis flexural strengths of uD-GFR/E demonstrate good fiber/nanophased-matrix interracial bonding. The interlaminar shear stress between the adjacent layers with different orientations/strains of duc- tile QI-GFR/SiC/E laminates results in decreasing the flexural strengths respectively by 24.3% and 9.1% for [0/±45/90]s and [90/± 45/0]s stacking sequences and increasing the dissipated interfacial friction energy and thus the damping by 105.7% and 26.1%. The damping of QI-GFR/E, QI-GFR/SiC/E and QI-GFR/AI203/E laminates with [90/± 45/0]s stacking sequence was increased by 111.4%, 29.7% and 32.9% respectively compared to [0/± 45/90]s stacking sequence.

关键词： Flexural properties GFRE composites Interracial bonding nanoparticles non-destructive vibrationtechnique

A parallel complex divider architecture based on DCD iterations for computing complex division in MVDR beamformer

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Journal of Systems Engineering and Electronics 2018年第6期29卷 1124-1135页

作者： KIDAV Jayaraj u SIVA Mangai n M PERuMAL M Pillai Karunya Institute of Technology and Sciences Coimbatore 641114India national Institute of Electronics and Information Technology Calicut 673601India

This paper presents a hardware architecture using mixed pipeline and parallel processing for complex division based on dichotomous coordinate descent(DCD) iterations. The objective of the proposed work is to achieve low-latency and resource optimized complex divider architecture in adaptive weight computation stage of minimum variance distortionless response(MVDR)algorithm. In this work, computation of complex division is modeled as a 2×2 linear equation solution problem and the DCD algorithm allows linear systems of equations to be solved with high degree of computational efficiency. The operations in the existing DCD algorithm are suitably parallel pipelined and the performance is optimized to 2 clock cycles per iteration. To improve the degree of parallelism, a parallel column vector read architecture is *** proposed work is implemented on the field programmable gate array(FPGA) platform and the results are compared with state-of-art literature. It concludes that the proposed architecture is suitable for complex division in adaptive weight computation stage of MVDR beamformer. We demonstrate the performance of the proposed architecture for MVDR beamformer employed in medical ultrasound imaging applications.

关键词： minimum variance distortionless response(MVDR) beamformer adaptive weight dichotomous coordinate descent(DCD) algorithm medical ultrasound imaging

Inter-relationship of Various Results in Analysis of （14.0 MeV／u） Pb＋Pb Reaction using Mica and Cn-85 Track Detectors

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Chinese Physics Letters 2005年第1期22卷 69-71页

作者： F.n.Khattak E.u.Khan Tabassumnasir J.J.Baluch F.u.Khan u.W.C. GomalUniversityDeraIsmailKhanPakistan RadiationPhysicsDivision PINSTECHNiloreIslamabadPakistan DepartmentofPhysics GomalUniversityDeraIsmailKhanPakistan

Two detector materials mica and cellulose-nitrate(Cn)-85 have been used to study (14.0MeV/u) Pb + Pb reaction. Events of different multiplicities were registered in mica and Cn-85 detectors using the 2π-geometry technique of solid state nuclear track detection. After removing the target material from the detectors the damaged trails in the detectors were revealed as tracks by proper chemical etching. The irradiated area of each sample was scanned and events of different multiplicities were traced. The binary events were bifurcated into elastic and inelastic events. The elastic binary events and three prong events, observed in the reaction, have been used to search out coefficients Cμν in the presence of both the detectors, for the reaction under study. using these coefficients 3- and 4-prong events have been analysed. From the detailed analysis of the results of (14.0MeV/u) Pb+Pb reaction, obtained from mica and Cn-85 track detectors we observed a great resemblance of results obtained from the two detectors. Combining the results of both the detectors, we report some important outcomes.

关键词： Cn-85轨迹探测器高能物理学铅原子碰撞反应固态

General investigation for longitudinal wave propagation under magnetic field effect via nonlocal elasticity

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Applied Mathematics and Mechanics(English Edition) 2015年第10期36卷 1305-1318页

作者： u.GVEn Department of Mechanical Engineering Yildiz Technical University

In this paper, the propagation of longitudinal stress waves under a longitu- dinal magnetic field is addressed using a unified nonlocal elasticity model with two scale coefficients. The analysis of wave motion is mainly based on the Love rod model. The effect of shear is also taken into account in the framework of Bishop＇s correction. This analysis shows that the classical theory is not sufficient for this subject. However, this unified nonlocal elasticity model solely used in the present study reflects in a manner fairly realistic for the effect of the longitudinal magnetic field on the longitudinal wave propagation.

关键词： Rayleigh-Bishop rod nonlocal elasticity magnetic field wave propagation

Optical coating and nano-structuring on plastics

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光学精密工程 2005年第4期13卷 459-464页

作者： u. Schulz P. Munzert A. Kaless n. Kaiser Fraunhofer Institut für Angewandte Optik und Feinmechnik Albert-Einstein-Str. 7 D-07745 Jena GermanyFraunhofer Institut für Angewandte Optik und Feinmechnik Albert-Einstein-Str. 7D-07745 Jena GermanyFraunhofer Institut für Angewandte Optik und Feinmechnik Albert-Einstein-Str. 7D-07745 Jena GermanyFraunhofer Institut für Angewandte Optik und Feinmechnik Albert-Einstein-Str. 7D-07745 Jena Germany

The coating of plastics for optical applications is intended to improve the mechanical durability of soft polymers and to serve an antireflection function. usually a classic four-layer antireflection system is added on top of a single-layer hard coating. With needle optimisation,an alternative coating design has been developed. Plasma ion assisted deposition was used to deposit coatings upon polymers. uniform antireflection and high scratch resistance have been achieved.

关键词：光学涂覆技术纳米结构塑料光学仪器

Physico-chemical characterization of a farmland affected by wastewater in relation to heavy metals

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Journal of Zhejiang university-Science A(Applied Physics & Engineering) 2008年第3期9卷 366-372页

作者： Emmanuel u. OnWEREMADu Department of Soil Science and Technology Federal university of Technology PMB 1526 Owerri Nigeria

This study investigated selected properties of soils affected by wastewater and its relationship with some heavy metals. A free survey technique involving target sampling was used in siting soil profile pits. Soil samples were collected based on horizon differentiation and analyzed using routine and special analytical techniques. Soil data were subjected to correlation analysis using SAS program. Results show that all heavy metals studied had values above critical limits in the polluted soils using known standards and that these biotoxic metals decreased with soil depths. Highly significant (P=0.01 and 0.05) relationships were established between investigated heavy metals and some soil properties, especially soil pH and organic matter. Further studies involving more edaphic properties, biotoxic metals and their bioaccessibility in crops growing on wastewater soils will surely enhance knowledge and management of these highly anthropogenically influenced soils of the study site.

关键词： Bioavailability Characterization Heavy metals Soil pollution Wastewater

Semi-solid near-net shape rheocasting of heat treatable wrought aluminum alloys

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Transactions of nonferrous Metals Society of China 2010年第9期20卷 1719-1724页

作者： u.A.C uRLE Materials Science and Manufacturing Council for Scientific and Industrial Research

Flexibility of the CSIR-RCS, induction stirring with simultaneous air cooling process, in combination with high pressure die casting is successfully demonstrated by semi-solid rheocasting of plates performed on commercial 2024, 6082 and 7075 wrought aluminum alloys. Tensile properties were measured for the above mentioned rheocast wrought aluminum alloys in the T6 condition. The results showed that tensile properties were close to or even in some cases exceeded the minimum specifications. The yield strength and elongation of rheocast 2024-T6 exceeded the minimum requirements of the wrought alloy in the T6 condition but the ultimate tensile strength achieved only 90% of the specification because the Mg content of the starting alloy was below the commercial alloy specification. The strengths of rheocast 6082-T6 exceeded all of the wrought alloy T6 strength targets but the elongation only managed 36% of the required minimum due to porosity, caused by incipient melting during solution heat treatment, and the presence of fine intermetallie needles in the eutectic. The yield strength of rheocast 7075 exceeded the required one and the ultimate tensile strength also managed 97% of the specification; while the elongation only reached 46% of the minimum requirement also due to incipient melting porosity caused during the solution heat treatment process.

关键词： high pressure die casting (HPDC) aluminum alloys as-cast condition T6 treatment incipient melting

Photoproduction of multi-meson final states–recent results from the Crystal-Barrel/TAPS experiment at ELSA-

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Chinese Physics C 2009年第12期33卷 1105-1112页

作者： u. Thoma HISKP Universitt Bonn Nussallee 14-16 53115 Bonn Germany

Multi-meson final states such as γp →pπ0π0 and γp →pπ0η have been investigated with the Crystal-Barrel/TAPS experiment at ELSA. Baryon cascades via △π and △η and also via higher mass baryon resonances are clearly observed. Based on this data and on data from other reactions a partial wave analysis has been performed from which partial decay widths of various n＊ and △＊ states into the different pπ0π0 and pπ0η decay channels have been determined, leading partly to unexpected results. In addition, polarisation observables have been investigated. The beam asymmetry X has been determined for both reactions and double polarisation data using a longitudinally polarised target and a circularly or linearly polarised photon beam has been taken. Given the angular coverage of the Crystal-Baxrel/TAPS experiment this data covers almost the full angular range and phase space. This data will provide new and important information for the partial wave analyses and bring us one step closer towards a complete experiment.

关键词： baryon spectroscopy photoproduction multi-meson final states polarisation observables