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11.
Haiping Du James Lam Kam Yim Sze 《Engineering Applications of Artificial Intelligence》2003,16(7-8):667-680
This paper presents an approach to design static output feedback and non-fragile static output feedback H∞ controllers for active vehicle suspensions by using linear matrix inequalities and genetic algorithms. A quarter-car model with active suspension system is considered in this paper. By suitably formulating the minimization problem of the sprung mass acceleration, suspension deflection and tyre deflection, a static output feedback H∞ controller and a non-fragile static output feedback H∞ controller are obtained. The controller gain is naturally constrained in the design process. The approach is validated by numerical simulation which shows that the designed static output feedback H∞ controller can achieve good active suspension performance in spite of its simplicity, and the non-fragile static output feedback H∞ controller has significantly improved the non-fragility characteristics over controller gain variations. 相似文献
12.
Modular Reconfigurable Robots in Space Applications 总被引:6,自引:0,他引:6
Mark Yim Kimon Roufas David Duff Ying Zhang Craig Eldershaw Sam Homans 《Autonomous Robots》2003,14(2-3):225-237
Robots used for tasks in space have strict requirements. Modular reconfigurable robots have a variety of attributes that are well suited to these conditions, including: serving as many different tools at once (saving weight), packing into compressed forms (saving space) and having high levels of redundancy (increasing robustness). In addition, self-reconfigurable systems can self-repair and adapt to changing or unanticipated conditions. This paper will describe such a self-reconfigurable modular robot: PolyBot. PolyBot has significant potential in the space manipulation and surface mobility class of applications for space. 相似文献
13.
14.
It is shown that the inclusion of an excited state step in parallel with a ground state charge-transfer step for a photoelectrode comprising a metal coated with an adsorbed dye leads to a different photovoltage-light intensity expression from that previously derived by Hillson and Rideal[4] who assumed simple displacement of the ground state charge-transfer process by light. The Hillson and Rideal expression is shown to be a valid approximation when illumination of the electrode only slightly perturbs the electrodic charge-transfer reactions. 相似文献
15.
Yuxiang Mo Sitaram Aryal Paul Rulis Wai‐Yim Ching 《Journal of the American Ceramic Society》2014,97(8):2646-2653
The term “MAX phase” refers to a very interesting and important class of layered ternary transition‐metal carbides and nitrides with a novel combination of both metal and ceramic‐like properties that have made these materials highly regarded candidates for numerous technological and engineering applications. Using (Cr2Hf)2Al3C3 as an example, we demonstrate the possibility of incorporating more types of elements into a MAX phase while maintaining the crystallinity, instead of creating solid solution phases. The crystal structure and elastic properties of MAX phase‐like (Cr2Hf)2Al3C3 are studied using the Vienna ab initio Simulation Package. Unlike MAX phases with a hexagonal symmetry (P63/mmc, #194), (Cr2Hf)2Al3C3 crystallizes in the monoclinic space group of P21/m (#11) with lattice parameters of a = 5.1739 Å, b = 5.1974 Å, c = 12.8019 Å; α = β = 90°, γ = 119.8509°. Its structure is found to be energetically much more favorable with an energy (per formula unit) of ?102.11 eV, significantly lower than those of the allotropic segregation (?100.05 eV) and solid solution (?100.13 eV) phases. Calculations using a stress versus strain approach and the VRH approximation for polycrystals also show that (Cr2Hf)2Al3C3 has outstanding elastic moduli. 相似文献
16.
Core-shell structured HAp-(t-ZrO2)/Al2O3-(m-ZrO2) composites were fabricated using a multi extrusion process. The shell of Al2O3-(m-ZrO2) phases was selected due to their excellent biocompatibility and mechanical properties and the core was designed with t-ZrO2 dispersed in the HAp matrix. The t-ZrO2 and m-ZrO2 particles (< 400 nm) were homogeneously dispersed in the HAp and Al2O3 phases, respectively. In the HAp-(t-ZrO2) core region, a heavy strain field contrast was observed due to the mismatch of their thermal expansion coefficients. The values of relative density, bending strength and Vickers hardness of the third pass fibrous HAp-(t-ZrO2)/Al2O3-(m-ZrO2) composites, which were sintered at 1400 °C, were about 93%, 169 MPa, and 792 Hv, respectively. 相似文献
17.
Eng Leong Tan Soon Yim Tan 《Antennas and Propagation, IEEE Transactions on》2001,49(8):1218-1225
This paper presents a rigorous formulation of the spectral-domain dyadic Green's functions for planar stratified bianisotropic media. The media may consist of any number of layers bounded by optional impedance/admittance walls. Both electric and magnetic dyadic Green's functions for arbitrary field and source locations are derived simultaneously. Based on the principle of scattering superposition, these dyadics are decomposed into unbounded and scattered parts. The scattered dyadic Green's functions are determined without cumbersome operations using the concepts of effective reflection and transmission of outward-bounded and inward-bounded waves. The scattering coefficient matrices are expressed in compact and convenient forms involving global reflection and transmission matrices. Corresponding to the impedance/admittance boundary walls, the global reflection matrices are related directly to the wall impedance/admittance dyadics. For illustration, the general expressions of dyadic Green's functions are applied to the configuration of a grounded bianisotropic slab embedded in isotropic halfspace 相似文献
18.
Effect of hardness on acute toxicity of metal mixtures using Daphnia magna: prediction of acid mine drainage toxicity 总被引:2,自引:0,他引:2
In this study, the effect of hardness on the combined outcome of metal mixtures was investigated using Daphnia magna. The toxic unit (TU) was calculated using modified LC(50) values based on the hardness (i.e., LC(50-soft) and LC(50-hard)). From a bioassay test, the degree of sensitivity to hardness on the toxicity changes was in the order: Cd相似文献
19.
Ki Won Sung Chae Y. Lee Kwang Hyuk Yim Agnes Gravrand 《Wireless Personal Communications》2009,50(4):469-481
Traffic asymmetry between uplink and downlink is expected to be a remarkable 3G characteristic in cellular mobile multimedia
communications. CDMA system with TDD is a good solution to this traffic asymmetry. However, the level of traffic asymmetry
may be significantly different from a cell to another cell. To tackle this problem and to support the traffic hot spot, crossed
slots are examined. The use of crossed slots is restricted within a certain range of a cell by investigating the inter-cell
interference and the maximum planned load factor. We examine the radius of inner zone and discuss the capacity of downlink
crossed slots for various neighbor cell environments. Computational results show that the capacity increase in the target
cell is outstanding by reducing the service range of neighbor cells. When all six neighbors reduce their service range by
20%, the capacity at target cell crossed slot is increased by 35%. Monte Carlo simulation is performed with large scale fading
to verify the numerical analysis.
相似文献
Chae Y. LeeEmail: |
20.
Yim Sang Ryun Park Ga Young Lee Kwang Won Chung Myung-Sub Shim Soon-Mi 《Food science and biotechnology》2017,26(1):293-298
Food Science and Biotechnology - The objectives of this study was to examine the amount of total arsenic and arsenic speciation in different types of rice from two areas in Korea using inductively... 相似文献