Dose and dose-rate dependence of optically stimulated signals in quartz: theoretical simulations

In a recent paper Bailey proposed a general model to describe many optically stimulated luminescence (OSL) and thermoluminescence properties of natural quartz. This model consists of five electron trapping centres and four recombination centres: one of the recombination centres is assumed to be radiative and the remaining non-radiative. This paper investigates some additional aspects of the Bailey model. Firstly, the single-aliquot regenerative-dose (SAR) method has been simulated using the model. It is shown that the simulated natural dose (2 Gy) given to the 'sample' in the simulation can be estimated to within approximately 2% using the SAR method. Furthermore, sensitivity-corrected OSL growth curves have been calculated over a dose range of 0 to 2500 Gy. Using the model, it is also demonstrated that the shape of the sensitivity-corrected OSL growth curve is independent of dose rate, for dose rates of 0.001 Gy x s(-1) and 0.1 Gy x s(-1), over a dose range of 0-500 Gy.     

Constructivist Management of Knowledge,Communication and Enterprise Innovation: Lessons from Indian Experience

Prime movers of enterprise innovation are inside the organisation. The enterprise NIIT, studied in this paper, tells us how elicitation and recognition of knowledge and its contents set an enterprise on the move. Recognised knowledge is actionable. Each act of recognition is an addition to knowledge content, and such additions took place in NIIT through acts of communications and self-searching. These contents form a large collage that cannot be strewn into a single novelistic episode. Perspectives and context, motives and suggestions render to each member of the enterprise different disjoint appearances of knowledge. There are thus many knowledge systems and multiple narrations, each with small episode-like finality. Enterprise innovation is achieved not through any grand episodic integration of all knowledge contents, but by constructively eliciting further new contents of knowledge, and encouraging acts of communications and discourses on this new knowledge. Constructive management of knowledge and communication towards enterprise innovation has thus been defined. Through such constructive management, NIIT enabled itself innovationally and empowered its members in eliciting knowledge and acting communicatively. A critical feature of knowledge work is that it requires multidisciplinary expertise and mutual learning in order to achieve a complex synthesis of highly specialised state-of-the-art technologies and knowledge domains. A convivial work culture and a culture of communicative acts enable sharing of the non-informatised yet recognised contents of knowledge.     

Free Transverse and Lateral Vibration of Beams with Torsional Coupling

The free vibration of beams whose flexural motions in both principal planes are coupled with torsion is investigated by using the dynamic stiffness method. First, the governing differential equations of motion in free vibration are derived using Hamilton’s principle. The dynamic stiffness matrix is then developed from the solution of these differential equations when the oscillatory motion of the beam is harmonic. Finally, the resulting dynamic stiffness matrix is applied with particular reference to the Wittrick–Williams algorithm to carry out the free vibration analysis of a few illustrative examples. The numerical results are discussed and this is followed by some concluding remarks.     

Novel Low-Overhead Operand Isolation Techniques for Low-Power Datapath Synthesis

Power consumption in datapath modules due to redundant switching is an important design concern for high-performance applications. Operand isolation schemes that reduce this redundant switching incur considerable overhead in terms of delay, power, and area. This paper presents novel operand isolation techniques based on supply gating that reduce overheads associated with isolating circuitry. The proposed schemes also target leakage minimization and additional operand isolation at the internal logic of datapath to further reduce power consumption. We integrate the proposed techniques and power/delay models to develop a synthesis flow for low-power datapath synthesis. Simulation results show that the proposed operand isolation techniques achieve at least 40% reduction in power consumption compared to original circuit with minimal area overhead (5%) and delay penalty (0.15%)     

An Analytical 1-D Model for Ion Implantation of Any Species into Single-Crystal Silicon Based on Legendre Polynomials

A computationally-efficient 1-D analytical model for ion implantation of any species into single crystal silicon is presented. By interpolating between a few species, the model can predict as-implanted profiles for all the other species. The model uses Legendre polynomials as basis functions. The results of the model are in good agreement with UT-MARLOWE, which is a physically-based and experimentally verified Monte Carlo simulator.     

Analysis of gate-bias-induced heating effects in deep-submicron ESD protection designs

This paper presents a detailed investigation of the degradation of electrostatic discharge (ESD) strength with high gate bias for deep-submicron salicided ESD protection nMOS transistors, which has significant implications for protection designs where high gate coupling occurs under ESD stress. It has been shown that gate-bias-induced heating is the primary cause of early ESD failure and that this impact of gate bias depends on the finger width of the protection devices. In addition, it has been established that substrate biasing can effectively alleviate the adverse impact of the gate bias and can improve ESD strength despite the gate-coupling level. Improved understanding of ESD behavior for advanced devices under high gate-coupling conditions can extend design capabilities of protection structures.     

Children''s understanding of extended identity

OBJECTIVE: To compare the properties of single myocytes isolated from different layers of the basal region of the left ventricle and to test the hypothesis that differences in the delayed rectifier current (IK) contribute to regional differences in action potential duration. METHODS: Myocytes were isolated from basal sub-endocardial, mid-myocardial and sub-epicardial layers of the guinea-pig left ventricle. Membrane voltage and current were measured using the switch-clamp technique. RESULTS: Mean action potential duration measured at 90% repolarisation (APD90) was longer in sub-endocardial myocytes than in mid-myocardial and sub-epicardial myocytes [APD90 ms at 0.2 Hz: sub-endocardial 292 +/- 12 (n = 40), mid-myocardial 243 +/- 8 (n = 42) and sub-epicardial 227 +/- 9 (n = 36), P < 0.001, analysis of variance (ANOVA)]. The APD-rate relationship (stimulation frequencies 2, 1, 0.2 and 0.017 Hz) was steeper in sub-endocardial than in mid-myocardial or sub-epicardial myocytes (P < 0.001, ANOVA). The density of IK was greater in mid-myocardial (4.05 +/- 0.09 pA pF-1) and sub-epicardial (3.90 +/- 0.41 pA pF-1) than in sub-endocardial myocytes (2.74 +/- 0.27 pA pF-1, P < 0.01 ANOVA). The rapidly-activating (IKr) and slowly-activating (IKs) components of IK were significantly smaller in sub-endocardial than in mid-myocardial or sub-epicardial myocytes. D,L-Sotalol-induced prolongation of APD90 was similar in the three regions studied. CONCLUSIONS: There are significant transmural gradients in the electrophysiological properties of myocytes isolated from the base of the left ventricular free wall in guinea-pig. Sub-endocardial myocytes had a longer APD90 attributable in part to a significantly smaller IK density. We have been unable to identify M cells in the guinea-pig left ventricular free wall.     

Homogeneous reduction of aromatic nitrocompounds by a triphenylphosphine complex of palladium

The complex Pd₂(PPh₃)₂Cl₄ has been used as a homogeneous catalyst for the reduction of C₆H₅NO₂ and p-ClC₆H₄NO₂ in basic ethanol. A reaction intermediate [Pd(PPh₃) (C₆H₅NO₂)Cl₂] has been isolated and characterised. Reduction of C₆H₅NO₂ produced aniline (75%), azobenzene (5%) and azoxybenzene (15%) under conditions of atmospheric pressure, while under conditions of high pressure the reduction product contained aniline (95%) only. The yield of p-ClC₆H₄NH₂ was highest (75%) at normal pressure and decreased with increasing pressure.