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排序方式: 共有1719条查询结果,搜索用时 15 毫秒
31.
Rituparna Datta Ajinkya Jain Bishakh Bhattacharya 《Structural and Multidisciplinary Optimization》2016,53(3):453-470
The field of robotics is evolving at a very high pace and with its increasing applicability in varied fields, the need to incorporate optimization analysis in robot system design is becoming more prominent. The present work deals with the optimization of the design of a 7-link gripper. As actuators play a crucial role in functioning of the gripper, the actuation system (piezoelectric (PZ), in this case) is also taken into consideration while performing the optimization study. A minimalistic model of PZ actuator, consisting different series and parallel assembly arrangements for both mechanical and electrical parts of the PZ actuators, is proposed. To include the effects of connector spring, the relationship of force with actuator displacement is replaced by the relation between force and the displacement of point of actuation at the physical system. The design optimization problem of the gripper is a non-linear, multi modal optimization problem, which was originally formulated by Osyczka (2002). In the original work, however, the actuator was a ‘constant output-force actuator model’ providing a constant output without describing the internal structure. Thus, the actuator model was not integrated in the optimization study. Four different cases of the PZ modelling have been solved using multi-objective evolutionary algorithm (MOEA). Relationship between force and actuator displacement is obtained using each set of non-dominated solutions. These relationships can provide a better insight to the end user to select the appropriate voltage and gripper design for specific application. 相似文献
32.
33.
S. K. Mishra L. C. Pathak V. Rao D. Bhattacharya K. L. Chopra 《Journal of Superconductivity》1996,9(2):211-216
Critical current densities of the superconducting Y-Ba-Cu-O (YBCO) films have been observed to decrease with the increase of power of microwave radiation. Presence of Josephson type of junctions in the microbridges has been established from the microwave irradiation and magnetic field studies. BCS energy gap parameter (2/kT
c
) has been calculated from thedI/dV characteristics and found to be 3.7 at 13 K. 相似文献
34.
An experimental study involving five independent lifting variables (namely weight, lift frequency, horizontal distance from the object, operator, and vertical distance) and their interactions was conducted using the Taguchi L27 design. Two responses—heart rate and oxygen uptake—were measured during each trial. To optimize both responses simultaneously, the signal‐to‐noise ratio was normalized to obtain a multi‐response signal‐to‐noise (MRSN) ratio for each trial. The MRSN ratio was analyzed using analysis of variance to identify the optimal condition in which both responses were optimized at the same time. Lift frequency was found to be the most significant factor, and operator and horizontal distance were found to be least significant. The empirical modeling equation was developed and can be used to predict the response values during experimental trials involving similar work conditions. © 2010 Wiley Periodicals, Inc. 相似文献
35.
We present a non-linear 2-D/2-D affine registration technique for MR and CT modality images of section of human brain. Automatic
registration is achieved by maximization of a similarity metric, which is the correlation function of two images. The proposed
method has been implemented by choosing a realistic, practical transformation and optimization techniques. Correlation-based
similarity metric should be maximal when two images are perfectly aligned. Since similarity metric is a non-convex function
and contains many local optima, choice of search strategy for optimization is important in registration problem. Many optimization
schemes are existing, most of which are local and require a starting point. In present study we have implemented genetic algorithm
and particle swarm optimization technique to overcome this problem. A comparative study shows the superiority and robustness
of swarm methodology over genetic approach. 相似文献
36.
Bhattacharya D Saha S Basu S Chakravarty S Chakravarty A Banerjee D Chakrabarti A 《Proteomics. Clinical applications》2010,4(5):480-488
Purpose: In (hemoglobin, Hb) HbEβ‐thalassemia, HbE (β‐26 Glu→Lys) interacts with β‐thalassemia to produce clinical manifestation of varying severity. This is the first proteomic effort to study changes in protein levels of erythrocytes isolated from HbEβ‐thalassemic patients compared to normal. Experimental design: We have used 2‐DE and MALDI‐MS/MS‐based techniques to investigate the differential proteome profiling of membrane and Hb‐depleted fraction of cytosolic proteins of erythrocytes isolated from the peripheral blood samples of HbEβ‐thalassemia patients and normal volunteers. Results: Our study showed that redox regulators such as peroxiredoxin 2, Cu‐Zn superoxide dismutase and thioredoxin and chaperones such as α‐hemoglobin stabilizing protein and HSP‐70 were upregulated in HbEβ‐thalassemia. We have also observed larger amounts of membrane associated globin chains and indications of disruption of spectrin‐based junctional complex in the membrane skeleton of HbEβ‐thalassemic erythrocytes upon detection of low molecular weight fragments of β‐spectrin and decrease in β‐actin and dematin content. Conclusion and clinical relevance: We have observed interesting changes in the proteomic levels of redox regulators and chaperons in the thalassemic hemolysates and have observed strong correlation or association of the extent of such proteomic changes with HbE levels. This could be important in understanding the role of HbE in disease progression and pathophysiology. 相似文献
37.
A high-precision method to study the dynamics of two-fluid interfaces using an optical tweezer and a phase-sensitive detection technique are described. The disturbances set up at the interface are studied by analyzing the motion of an optically trapped particle in the bulk of the fluid, i.e., away from the interface. The usefulness of the technique is demonstrated for the well-known problem of a horizontally vibrated sessile liquid drop. The vibrational modes of the liquid drop excited by sinusoidally vibrating the support in a horizontal plane appear as resonances in the motion of the trapped particle. The nature of the resonance is studied in detail by measuring the real part, the imaginary part, and the phase response of the motion of the particle as a function of the "effective" size of the liquid drop. Excellent quantitative agreement with the theoretically predicted values of the eigenfrequencies and damping of the surface modes is obtained. 相似文献
38.
39.
Kevin Zhang Bhattacharya U. Zhanping Chen Hamzaoglu F. Murray D. Vallepalli N. Yih Wang Bo Zheng Bohr M. 《Solid-State Circuits, IEEE Journal of》2006,41(1):146-151
Column-based dynamic power supply has been integrated into a high-frequency 70-Mb SRAM design that is fabricated on a high-performance 65-nm CMOS technology. The fully synchronized design achieves a 3-GHz operating frequency at 1.1-V power supply. The power supply at SRAM cell array is dynamically switched between two different voltage levels during READ and WRITE operations. Silicon measurement has proven this method to be effective in achieving both good cell READ and WRITE margins, while lowering the overall SRAM leakage power consumption. 相似文献
40.
The effects of anions like Cl-, Br-, NO
3
-
and SO
4
2-
on the anodic dissolution of the monolithic Al 6061 alloy have been investigated at neutral pH through immersion testing
and electrochemical techniques like potentiodynamic polarization and a.c. impedance spectroscopy. Scanning electron microscopy
was employed to characterize the corroded surface and to observe the extent of pitting in different media. From the evaluated
corrosion parameters it was found that the dissolution of the matrix was extensively reduced in presence of aqueous solutions
containing Br-, NO
3
-
and SO
4
2-
ions while Cl- ions aggravated corrosion by penetrating into the barrier oxide film on the surface of the material. Pronounced effect of
pitting was observed in presence of Cl- and the level of pitting in NO
3
-
and Br- were mild. In presence of SO
4
2-
ions passivity was extended over a wide potential range and breakdown of passivity occurs when the material was polarized
beyond pitting potential. The departure of capacitive behaviour towards resistive behaviour was clearly observed through impedance
measurements when investigations were conducted in Cl- media and in presence of the other electrolytes. Corrosion rates were, however, controlled during prolonged exposure in the
electrolytic media, specially in case of chloride media, due to the predominance of film repair kinetics. 相似文献