A Liapunov-Like Characterization of Bounded Input Bounded State Stability

1998 ◽  
Vol 31 (17) ◽  
pp. 477-481
Author(s):  
A. Bacciotti
Keyword(s):  
Bounded State ◽  
Bounded Input

Dynamic positioning for underactuated surface vessel via L1 adaptive backstepping control

2020 ◽  
pp. 014233122095296
Author(s):  
Huizi Chen ◽  
Yan Peng ◽  
Dan Zhang ◽  
Shaorong Xie ◽  
Huaicheng Yan
Keyword(s):  
Transient Response ◽  
Nonlinear Observer ◽  
Extremum Seeking ◽  
Dynamic Positioning ◽  
Fast Transient Response ◽  
Bounded State ◽  
Control Scheme ◽  
Fast Adaptation ◽  
Bounded Input ◽  
Surface Vessel

This paper is concerned with the problem that fast-transient response and excellent robustness cannot be satisfied simultaneously in the process of dynamic positioning (DP) for underactuated surface vessel (USV) in shallow water. By combing the improved L1 adaptive control with backstepping method, a novel control scheme is designed, which can ensure a fast adaptation with a guaranteed smooth transient response without any overshoot and chattering phenomenon. System uncertainties and disturbances are estimated by the nonlinear observer. Moreover, the optimized extremum seeking control (ESC) is employed to reduce energy consumption under environmental disturbances. Rigorous theoretical analysis shows that all closed-loop signals are bounded-input bounded-state. Simulation and sea test results are presented to illustrate the effectiveness and the robustness of the proposed strategy under the condition of external disturbances and parametric uncertainties.

Morphological Characterization of Mycobacteriophage R1

1974 ◽  
Vol 32 ◽  
pp. 254-255
Author(s):  
B. L. Soloff ◽  
T. A. Rado
Keyword(s):  
Carbon Source ◽  
Stationary Phase ◽  
Growth Phase ◽  
Minimal Medium ◽  
Morphological Characterization ◽  
Logarithmic Growth Phase ◽  
Complete Lysis ◽  
Lysogenic Culture ◽  
Logarithmic Growth

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.

AEM analysis of crystallization in Ti-based amorphous alloys

1983 ◽  
Vol 41 ◽  
pp. 270-271
Author(s):  
A.R. Pelton ◽  
A.F. Marshall ◽  
Y.S. Lee
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloys ◽  
Amorphous Materials ◽  
Isothermal Annealing ◽  
Amorphous Matrix ◽  
Nucleation And Growth ◽  
Current Interest ◽  
Amorphous Films ◽  
Electrical And Magnetic Properties

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.

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