Transient pulse evolution of active mode locking in an intracavity frequency-doubled laser

The theory of transient mode locking for an active modulator in an intracavity frequency-doubled laser is presented. The theory is applied to mode-locked and intracavity frequency-doubled Nd:YAG laser and the mode-locked pulse width is plotted as a function of number of round trips inside the cavity. It is found that the pulse compression is faster and the system takes a very short time to approach the steady state in the presence of a second harmonic generating crystal inside the laser cavity. The effect of modulation depth and the second harmonic conversion efficiency on the temporal behavior of the pulse width is discussed. Journal of Applied Physics is copyrighted by The American Institute of Physics.

Feeding mode of Australian infants in the first 12 months of life: An assessment against national breastfeeding indicators

Background: In 2011, Australia published a set of 6 population-level indicators assessing breastfeeding, formula use, and the introduction of soft/semisolid/solid foods. Objectives: This study aimed to report the feeding practices of Australian infants against these indicators and determine the predictors of early breastfeeding cessation and introduction of solids. Methods: Mother–infant dyads (N = 1470) were recruited postnatally in 2 Australian capital cities and regional areas of 1 state between February 2008 and March 2009. Demographic and feeding intention data were collected by self-completed questionnaire at infant birth, with feeding practices (current feeding mode, age of breastfeeding cessation, age of formula and/or solids introduction) reported when the infant was between 4 and 7 months of age, and around 13 months of age. Multiple logistic regression was used to determine the predictors of breastfeeding cessation and solids introduction. Results: Although initiation of breastfeeding was almost universal (93.3%), less than half of the infants were breastfed to 6 months (41.7%) and 33.3% were receiving solids by 4 months. Women who were socially disadvantaged, younger, less educated, unpartnered, primiparous, and/or overweight were most likely to have ceased breastfeeding before 6 months of age, and younger and/or less educated women were most likely to have introduced solid food by 4 months of age. Not producing adequate milk was the most common reason provided for cessation of breastfeeding. Conclusion: The feeding behaviors of Australian infants in the first 12 months fall well short of recommendations. Women need anticipatory guidance as to the indicators of breastfeeding success and the tendency of women to doubt the adequacy of their breast milk supply warrants further investigation.

Normal-mode sound propagation in an ocean with sinusoidal surface waves

The normal-mode solution to the problem of acoustic wave propagation in an isovelocity ocean with a wavy surface is considered. The surface wave amplitude is assumed to be small compared to the acoustic wavelength, and the method of multiple scales is employed to study the interaction between normal-mode acoustic waves and the surface waves. A nonresonant interaction causes small fluctuations of the amplitude and phase of the acoustic wave at a rate dependent on the frequency of the surface wave. Backscatter occurs if the wavenumber of the surface wave is larger than that of the acoustic wave. The interaction becomes resonant if appropriate phase-matching conditions are satisfied. In this case, two acoustic normal modes get coupled, resulting in a large-scale periodic exchange of energy from one mode to another.

Mode of Coordination and Chemical Reactivity of Alpha-Imine Hydrasone Ligands

Interaction of nickel(I1) and copper(I1) complexes of 4,9-dimethy1-5,8-diazadodeca-4,8diene-2,1 ldione, Ni(baen) and 4,6,9-trimethyl-5, 8diazadodeca-4,8-diene-2,ll-dione, Ni(bapn), with arene diazonium chlorides in buffered solutions of methanol yielded metal derivatives of glyoxaliminearylhydrazones. This typical electrophilic addition at the 3-carbon of the complex occurs owing to the pseudo aromatic behaviour of the chelate ring. A mechanism which predicts the attack of the diazonium cation through the coordination shell of the metal is well documented from the available experimental evidences. The chemical reactivity of a few complexes with a single residual non-substituted y-carbon is reasonably manifested by their reaction with phenyl isocyanate.

Determination of mode 1 notch stress intensity factor by the photoelastic technique

The structural integrity of any member subjected to a load gets impaired due to the presence of cracks or crack-like defects. The notch severity is one of the several parameters that promotes the brittle fracture. The most severe one is an ideal crack with infinitesimal width and infinitesimal or zero root radius. Though analytical investigations can handle an ideal crack, experimental work, either to validate the analytical conclusions or to impose the bounds, needs to be carried out on models or specimens containing the cracks which are far from the ideal ones. Thus instead of an ideal crack with infinitesimal width the actual model will have a slot or a slit of finite width and instead of a crack ending in zero root radius, the model contains a slot having a finite root radius. Another factor of great significance at the root is the notch angle along which the transition from the slot to the root takes place. This paper is concerned with the photoelastic determination of the notch stress intensity factor in the case of a “crack” subjected to Mode 1 deformation.

Effect of configuration of the inhibitors on the mode of binding to the enzyme, thermolysin

Preferred conformations of the competitive inhibitors glycyl-L-phenylalanine and glycyl-D-phenylalanine and their mode of binding to thermolysin have been studied. The difference in configuration is shown to affect significantly the mode of binding to thermolysin. Gly-D-Phe prefers to enter the active site in the global minimum conformation whereas Gly-L-Phe may enter in a higher energy conformation. Moreover, D-enantiomer is shown to have a better fit than the L-counterpart in the active site.

Electrode kinetics of a nickel/cadmium cell and failure-mode prediction. Estimation of equivalent resistance of an internal short

A quantitative expression has been obtained for the equivalent resistance of an internal short in rechargeable cells under constant voltage charging.

Characterization of a toxin from Parthenium hysterophorus and its mode of excretion in animals

Fractionation of methanolic extracts of air dried aerial parts ofParthenium resulted in the isolation of a toxic constituent which was identified as parthenin, the major sesquiterpene lactone from the weed. The LD50 (minimal lethal dose required to cause 50% mortality) for parthenin in rats was 42 mg/kg body weight. When [3H]-parthenin was given orally or by intravenous administration, radioactivity appeared in the milk of lactating laboratory and dairy animals. Tissue distribution of radioactivity revealed that maximum label was detectable in kidneys.

Transient pulse evolution of active-mode locking in an intra-cavity frequency-doubled laser

The theory of transient mode locking for an active modulator in an intracavity frequency-doubled laser is presented. The theory is applied to mode-locked and intracavity frequency-doubled Nd:YAG laser and the mode-locked pulse width is plotted as a function of number of round trips inside the cavity. It is found that the pulse compression is faster and the system takes a very short time to approach the steady state in the presence of a second harmonic generating crystal inside the laser cavity. The effect of modulation depth and the second harmonic conversion efficiency on the temporal behavior of the pulse width is discussed.

Photoelastic determination of mode i stress intensity factor in tensile strips—effect of crack length

This paper reports an experimental investigation carried out, using the photoelastic technique, to determine the Mode I stress intensity factor in case of cracks of varying a/w ratio in single edge-notch specimens. The photoelastic information was analysed using the several methods proposed by earlier workers. The experimental results are compared with the analytical expressions.

Stability criteria for single pulse solutions of cw passive mode-locked lasers

The stability of the steady-state solutions of mode-locking of cw lasers by a fast saturable absorber is imvestigated. It is shown that the solutions are stable if the condition (Ps/Pa) = (2/3) (P0Pa) is satisfied, where (Ps/Pa) is the steady-state la ser power, (P0/Pa) is the power at mode-locking threshold, and Pa is the saturated power of the absorber.

Negative resistance mode of forced oscillations of a string

A new mode of driven nonlinear vibrations of a stretched string is investigated with reference to conditions of existence, properties, and regions of stability. It is shown that this mode exhibits negative resistance properties at all frequencies and driving force amplitudes. Discovery of this mode helps to fill certain gaps in the theory of forced nonlinear vibrations of strings.

Two-Mode Structure of Alfvén Surface Waves

The Alfvén surface waves propagating along a viscous conducting fluid-vacuum interface have been studied. It is found that besides the "ordinary" Alfvén surface waves, modified by viscosity effects, the interface can support a second mode which is the over-damped solution of the dispersion equation. The possibility of observation of a two-mode structure of Alfvén surface waves in the laboratory and in the solar coronal plasmas is discussed.

Mode of inhibition of mitochondrial energy transduction by chlorophenoxyisobutyrate

1. a-p-Chlorophenoxyisobutyric acid, the ethyl ester of which is widely used as an antihypercholesterolaemic drug, is an inhibitor of energy-transfer reactions in isolated rat liver mitochondria. 2. The compound at lower concentrations (<4.0mmol/mg of mitochondrial protein) inhibits state 3 oxidation, stimulates state 4 oxidation, abolishes respiratory control and stimulates the latent adenosine triphosphatase activity of mitochondria. The inhibition imposed on state 3 oxidation is relieved by dinitrophenol. 3. At higher concentrations it inhibits coupled phosphorylation as well as dinitrophenol-stimulated adenosine triphosphatase activity. The inhibition of state 3 oxidation under these conditions is not reversed by uncouplers. 4. The three coupling sites of phosphorylation exhibit differential susceptibility to inactivation by this compound. Coupled phosphorylation at the first site is abolished at a drug concentration of 3.0mmol/mg of protein. The third site is inactivated when the concentration of the drug reaches 5.0mmol/mg of protein. The second site is the most refractory and drug concentrations of the order of 10.0mmol/mg of protein are required effectively to inhibit phosphorylation at this site. 5. The compound also inhibits ATP-dependent reversal of electron transport as well as the adenosine triphosphatase activity in submitochondrial particles. 6. The oxidation of NADH and succinate in these particles is not inhibited. 7. These properties indicate that the compound acts as an `inhibitory uncoupler' of energy-transfer reactions in isolated mitochondria.