Asymptotic Expansions of Posterior Distributions in Nonregular Cases

We study the asymptotic behaviour of the posterior distributions for a one-parameter family of discontinuous densities. It is shown that a suitably centered and normalized posterior converges almost surely to an exponential limit in the total variation norm. Further, asymptotic expansions for the density, distribution function, moments and quantiles of the posterior are also obtained. It is to be noted that, in view of the results of Ghosh et al. (1994, Statistical Decision Theory and Related Topics V, 183-199, Springer, New York) and Ghosal et al. (1995, Ann. Statist., 23, 2145-2152), the nonregular cases considered here are essentially the only ones for which the posterior distributions converge. The results obtained here are also supported by a simulation experiment.     

Amphoteric trap modeling of multidielectric scaled SONOS nonvolatile memory structures

We have characterized multidielectric scaled SONOS nonvolatile memory structures with the quasi-static linear voltage ramp (LVR) technique and dynamic pulse measurements. We have formulated physically-based ERASE/WRITE and retention methods with deep level amphoteric traps which capture and emit carriers to the bands in the silicon nitride film. Amphoteric trap parameters are extracted by the LVR technique. ERASE/WRITE and retention amphoteric trap model simulations agree well with the experimental dynamic pulse measurements. Experimental scaled SONOS structures have been fabricated with tunnel oxide X_OT=20 Å, nitride X_N=30 Å and blocking oxide X_OB=55 Å and demonstrated a static flatband shift of 3.6 V with ±5 V programming voltages. These structures may be used as the nonvolatile memory element in high density VLSI circuits.     

Analysis of finite capacity discrete-time <Emphasis Type="Italic">GI</Emphasis>/<Emphasis Type="Italic">Geo</Emphasis>/1 queueing system with multiple vacations

This paper investigates a discrete-time single-server finite-buffer queueing system with multiple vacations in which arrivals occur according to a discrete-time renewal process. Service and vacation times are mutually independent and geometrically distributed. We obtain steady-state system length distributions at prearrival, arbitrary and outside observer's observation epochs under the late arrival system with delayed access and early arrival system. The analysis of actual waiting-time for both the systems has also been carried out. The model has potential application in high-speed computer network, digital communication systems and other related areas.     

Aeroelastic flutter of a disk rotating in an unbounded acoustic medium

The linear aeroelastic stability of an unbaffled flexible disk rotating in an unbounded fluid is investigated by modeling the disk-fluid system as a rotating Kirchhoff plate coupled to the irrotational motions of a compressible inviscid fluid. A perturbed eigenvalue formulation is used to compute systematically the coupled system eigenvalues. Both a semi-analytical and a numerical method are employed to solve the fluid boundary value problem. The semi-analytical approach involves a perturbation series solution of the dual integral equations arising from the fluid boundary value problem. The numerical approach is a boundary element method based on the Hadamard finite part. Unlike previous works, it is found that a disk with zero material damping destabilizes immediately beyond its lowest critical speed. Upon the inclusion of small disk material damping, the flutter speeds become supercritical and increase with decreasing fluid density. The competing effects of radiation damping into the surrounding fluid and disk material damping control the onset of flutter at supercritical speed. The results are expected to be relevant for the design of rotating disk systems in data storage, turbomachinery and manufacturing applications.     

Electrical characterization of low temperature deposited TiO2 films on strained-SiGe layers

Thin films of titanium dioxide have been deposited on strained Si_0.82Ge_0.18 epitaxial layers using titanium tetrakis-isopropoxide [TTIP, Ti(O-i-C₃H₇)₄] and oxygen by microwave plasma enhanced chemical vapor deposition (PECVD). The films have been characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Dielectric constant, equivalent oxide thickness (EOT), interface state density (D_it), fixed oxide charge density (Q_f/q) and flat-band voltage (V_FB) of as-deposited films were found to be 13.2, 40.6 Å, 6×10¹¹ eV⁻¹ cm⁻², 3.1×10¹¹ cm⁻² and −1.4 V, respectively. The capacitance–voltage (C–V), current–voltage (I–V) characteristics and charge trapping behavior of the films under constant current stressing exhibit an excellent interface quality and high dielectric reliability making the films suitable for microelectronic applications.     

4-Aminophthalimide Derivatives as Environment-Sensitive Probes

The potential of 4-aminophthalimide (AP) and its derivatives as fluorescence probes for organized media is highlighted. The fluorescence response of AP, as measured from the position of the fluorescence maximum, fluorescence intensity and lifetime, is highly sensitive to the polarity of the medium. The sensitivity of the fluorescence parameters is further enhanced due to the involvement of the emitting intramolecular charge transfer state in hydrogen bonding interaction with the solvent molecules containing hydroxyl groups. It is shown that the microheterogeneous environments of organized media such as cyclodextrins and micelles can be very conveniently monitored using this probe. The results of the investigations carried out employing AP and its derivatives as fluorescence probe molecules in these media clearly suggest that a combination of the hydrophobic interaction with the host media and hydrogen bonding interaction with the solvent molecules determine the location of the fluorophore, which in all cases is found to be the interfacial region separating the nonpolar core of the micelle or the cyclodextrin cavity and the polar aqueous environment. Guidelines for the design of probes of this class of systems for the nonpolar core region of the micelles are provided and possible ways to increase the sensitivity of the fluorescence response of the systems are suggested.     

Studies on metal — protein interactions: Inter-comparison among various approaches

Binding ability of mercury, thallium, lead and bismuth with Erythrina variegata seed protein have been investigated using tracer packet technique. Due to the lack of standard methods, inter-comparisons have been made among three different approaches, like trichloroacetic acid (TCA) precipitation, isoelectric precipitation and dialysis of protein after incubation with the metals. Good agreement was observed for all the cases except that of lead.     

Extending Coggia–Couvreur attack on Loidreau’s rank-metric cryptosystem

Designs, Codes and Cryptography - A recent paper by Coggia and Couvreur presents a polynomial time key-recovery attack on Loidreau’s encryption scheme, based on rank-metric codes, for some...     

A facile synthesis of natural products chaetomellic acid A and 1,7(Z)- nonadecadiene-2,3-dicarboxylic acid

Synthesis of recently isolated bioactive natural products chaetomellic acid A anhydride (1) and a novel 1,7(Z)-nonadecadiene-2,3-dicarboxylic acid (2) have been described. Chemoselective carbon[bond]carbon S(N)2' coupling reactions of appropriate Grignard reagents with dimethyl bromomethylfumarate (7) in diethyl ether in the presence of HMPA at room temperature furnished the corresponding diesters 8 and 15 in 60-62% yields. The formed diesters 8 and 15 on hydrolysis gave respectively the corresponding desired diacids 9 and 2 in quantitative yields. Acetic anhydride induced ring closure of diacids 9 and 2 respectively gave the chaetomellic acid A anhydride (1) and isochaetomellic acid B anhydride (16) with 38-39% overall yields in five steps.     

Fluorescence signalling of the transition metal ions: Design strategy based on the choice of the fluorophore component

Transition metal ions are notorious for their fluorescence quenching abilities. In this paper, we discuss the design strategies for the development of efficientoff-on fluorescence signalling systems for the transition metal ions. It is shown that even simplefluorophore-spacer-receptor systems can display excellentoff-on fluorescence signalling towards the quenching metal ions when the fluorophore component is chosen judiciously.