Effect of the Intrinsic Width on the Piezoelectric Force Microscopy of a Single Ferroelectric Domain Wall

Intrinsic domain wall width is a fundamental parameter that reflects bulk ferroelectric properties and governs the performance of ferroelectric memory devices. We present closed-form analytical expressions for vertical and lateral piezoelectric force microscopy (PFM) profiles for the conical and disc models of the tip, beyond point charge and sphere approximations. The analysis takes into account the finite intrinsic width of the domain wall, and dielectric anisotropy of the material. These analytical expressions provide insight into the mechanisms of PFM image formation and can be used for quantitative analysis of the PFM domain wall profiles. PFM profile of a realistic domain wall is shown to be the convolution of its intrinsic profile and resolution function of PFM.Comment: 25 pages, 5 figures, 3 tables, 3 Appendices, To be submitted to J. Appl. Phy

Full-order observer design for a class of port-Hamiltonian systems

We consider a special class of port-Hamiltonian systems for which we propose a design methodology for constructing globally exponentially stable full-order observers using a passivity based approach. The essential idea is to make the augmented system consisting of the plant and the observer dynamics to become strictly passive with respect to an invariant manifold defined on the extended state-space, on which the state estimation error is zero. We first introduce the concept of passivity of a system with respect to a manifold by defining a new input and output on the extended state-space and then perform a partial state feedback passivation which leads to the construction of the observer. We then illustrate this observer design procedure on two physical examples, the magnetic levitation system and the inverted pendulum on the cart system. (C) 2010 Elsevier Ltd. All rights reserved.</p

Irrawaddy dolphin (Orcaella brevirostris) washed ashore on Digha Coast, West Bengal, India

239-242The residual population of the Irrawaddy dolphin in India is one of the most vulnerable marine mammals. Stranded dead male animal of Irrawaddy dolphin length from Digha coast with severed tail and centre of the body is reported in this manuscript

Progressive cavitating leukoencephalopathy: Case report of a rare childhood onset neurodegenerative disease

The leukoencephalopathies with cystic changes form a distinct subtype of childhood onset neurodegenerativedisorders. This group has heterogeneous etiological differentials that primarily include mitochondrial disorders, someleukodystrophies and central nervous system infections. We report this case of a 17-month old girl who presented withseizures, episodic encephalopathy, elevated blood lactate level and lactate peak on magnetic resonance spectroscopy,a typical imaging picture noted on cranial magnetic resonance imaging and absence of deletions or duplications ofmitochondrial deoxyribonucleic acid. Progressive cavitating leukoencephalopathy (PCL) is a recently described entitywith only a few cases reported so far. We report the first case of PCL from India. Accurate diagnosis can be made, notonly, by the presence of typical clinicoradiological findings of PCL, but also by the awareness of, and, ruling out of,the various other differential diagnoses that are discussed in detail below