Effect of curve crossing on absorption and resonance Raman spectra: analytical treatment for delta-function coupling in parabolic potentials

We propose an exactly solvable model for the two-state curve-crossing problem. Our model assumes the coupling to be a delta function. It is used to calculate the effect of curve crossing on the electronic absorption spectrum and the resonance Raman excitation profile.

Codoping Effect of Zn and Pr in YBa2Cu3O7-delta

In this paper we present the resistivity data for Pr and Zn codoped compound Y1-xPrxBa2[Cu1-yZny](3)O7-delta with 0 < y < 0.1 and x = 0.0, 0.1 and 0.2. The data is analysed in terms of the superconducting critical temperature T-c, residual resistivity rho(0) and the resistivity slope d rho/dT corresponding to the linear rho-T region. It is found that for x = 0.1 Pr has a minimal influence on the in-plane processes for Zn impurity alone affecting slightly T-c and rho(0). The slope dp/dT becomes larger for 0.03 < y < 0.06 leading to larger depining effect and hence slower fall of T, as a function of y. For x = 0.2 there is a drastic change, rho(0) becomes abnormally large, d rho/dT becomes negative implying absence of depinning and a totally pinned charge stripes. Superconductivity vanishes at y = 0.03. It is concluded that for x = 0.2 Pr converts the system from overdoped to underdoped region leading to the universal superconductor-insulator transition.

Purification, properties and synthesis of delta-aminolaevulinate dehydratase from Neurospora crassa.

Delta-aminolaevulinate dehydratase, the second and rate-limiting enzyme of the haem-biosynthetic pathway, was purified 300-fold from induced cultures of Neurospora crassa. The native enzyme has a mol.wt. of about 350000, whereas the salt-treated enzyme after incubation at 37 degrees C for 10 min has a mol.wt. of about 232000. The mol.wt. of the subunit is about 38000. Antibodies to the purified enzyme were raised in rabbits. By using radiolabelling and immunoprecipitation techniques it was shown that addition of iron and laevulinate to iron-deficient cultures brings about a significant increase in the synthesis of the enzyme, and protoporphyrin, the penultimate end product of the pathway, represses enzyme synthesis.

Relation between high-tc superconductivity and structure - a study of la3-xba3+xcu6o14+delta and yba2cu3o7-delta systems

Superconductivity is found in tetragonal La3−x Ba3+x Cu6O14+δ and La, Ba)6−x Sr x Cu6O14+δ even though they do not possess Cu-O chains or the K2NiF4 structure. Resistivity measurements confirm the occurrence of a transformation from chain-superconductivity to sheet-superconductivity in YBa2Cu3O7−δ as δ is varied in the range 0.0–0.5.

Hybrid constant factor incremental delta modulators

The paper presents a new adaptive delta modulator, called the hybrid constant factor incremental delta modulator (HCFIDM), which uses instantaneous as well as syllabic adaptation of the step size. Three instantaneous algorithms have been used: two new instantaneous algorithms (CFIDM-3 and CFIDM-2) and the third, Song's voice ADM (SVADM). The quantisers have been simulated on a digital computer and their performances studied. The figure of merit used is the SNR with correlated, /?C-shaped Gaussian signals and real speech as the input. The results indicate that the hybrid technique is superior to the nonhybrid adaptive quantisers. Also, the two new instantaneous algorithms developed have improved SNR and fast response to step inputs as compared to the earlier systems.

Phase separation versus spin glass behavior in La0.85Sr0.15CoO3

We present comprehensive studies of dc magnetization, ac susceptibility, and magnetotransport of two sets of La0.85Sr0.15CoO3 samples, one exhibits phase separation and the other exhibits spin glass behavior. Our study reveals that the phase separation in La0.85Sr0.15CoO3 is neither inherent nor ubiquitous; rather, it is a consequence of preparation condition. It is realized that the low temperature annealed sample exhibits phase separation while the high temperature annealed one shows the characteristic of spin glass behavior. This study shows that the most probable magnetic state of La0.85Sr0.15CoO3 is spin glass.

Coastal Wetlands Resources Investigation of the Burdekin Delta for declaration as fisheries reserves. Report to Ocean Rescue 2000

A project to investigate the coastal wetland resources of the Burdekin Delta, north Queensland, was undertaken as part of the long-term assessment of the coastal fisheries resources of Queensland. Extending from November 1993 to May 1995, fieldwork was undertaken in November 1993 and August 1994. The scope of the coastal wetlands resources investigation of the Burdekin Delta for declaration as a Fish Habitat Area was: 1. To document and map the marine wetland vegetation communities in the Burdekin River delta. 2. To document levels of existing disturbance to wetlands, existing recreational and commercial fisheries resources, and existing fishing activities. 3. To evaluate the conservation values of the areas investigated from the viewpoint of fisheries productivity and as habitat for important/threatened species. 4. To initiate Fish Habitat Area declaration under Section 120 of the Queensland Fisheries Act 1994 with formal consultation to all stakeholders. This report concentrates on Points 1 and 3, the documentation of the marine wetland vegetation communities and the evaluation of conservation values from a fisheries viewpoint. Dataset URL Link: Queensland Coastal Wetlands Resources Mapping data. [Dataset]

Force Measurements on a Reflex Cambered Delta Wing

AREFLEX spanwise cambered delta wing with a conical camber designed for M= 1.4, using the method of Ref. 1, was tested at the design Mach number as well as off-design Mach number M=0.15 and 2.3, respectively. The test results are compared with those of a plane wing and also with the available theoretical results at the design condition. At subsonic speed, the cambered wing has less lift at a given incidence and higher lift-to-drag ratio at a given lift than the plane wing, while at supersonic speeds, both of these quantities were less on the cambered wing. At supersonic speed, at the design incidence and Mach number, there is good agreement between results from theory and experiment. The center of pressure on the cambered wing is ahead of that on the plane wing at subsonic speed, while the reverse is true at supersonic speeds. Finally, it is found that over a useful range of lift the cambered wing is aerodynamically more efficient at subsonic speeds, and less so at supersonic speeds, than the plane wing.

Constant factor incremental delta modulator

This paper presents a new algorithm for the step-size change of instantaneous adaptive delta modulator. The present strategy is such that the step-size at any sampling instant can increase or decrease by either of the two constant factors or can remain the same, depending upon the combination of three or four most recent output bits. The quantizer has been simulated on a digital computer, and its performance compared with other quantizers. The figure of merit used is the SNR with gaussian signals as the input. The results indicate that the new design can give an improved SNR over a wider dynamic range and fast response to step inputs, as compared to the earlier systems.

A 105K superconductor with three Cu---O layers in the bismuth cuprate system : Bi1.5Pb0.5Ca2.5Sr1.5Cu3O10+delta

The n=3 member of the Bi1.5Pb0.5 (Ca, Sr) n+1CunO2n+4+δ system has been prepared and characterized by X-ray diffraction and electron microscopy. High-Tc superconductivity in the n=3 member has been established by resistivity, AC susceptibility and microwave absorption measurements. It has a Tc of not, vert, similar 105K compared to a Tc of not, vert, similar 82K of the corresponding n=2 member.

Ce1-xRuxO2-delta (x=0.05, 0.10): A New High Oxygen Storage Material and Pt, Pd-Free Three-Way Catalyst

Nanocrystalline Ce1-xRuxO2-delta (x = 0.05 and 0.10) of 8-10 nm sizes have been synthesized by hydrothermal method using melamine as complexing agent. Compounds have been characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray analysis (EDX) and their structures have been refined by the Rietveld method.The compounds crystallize in fluorite structure and the composition is Ce1-xRuxO2-x/2 where Ru is in +4 state and Ce is in mixed-valence (+3, +4) state. Substitution of Ru4+ ion in CeO2 activated the lattice oxygen. Ce1-xRuxO2-x/2 reversibly releases 0.22[O] and 0.42[O] for x = 0.05 and 0.10, respectively, which is higher than the maximumpossible OSC of 0.22 [O] observed for Ce0.50Zr0.50O2. Utilization of Higher OSC of Ce1-xRuxO2-delta (x = 0.05 and 0.10) is also reflected in terms of low-temperature CO oxidation with these catalysts, both in the presence and absence of feed oxygen. The Ru4+ ion acts as an active center for reducing molecules (CO, hydrocarbon ``HC'') and oxide ion vacancy acts as an active center for O-2 and NO, leading to low-temperature NO conversion to N-2. Thus due to Ru4+ ion, Ce1-xRuxO2-delta is not just a high oxygen storage material but also shows high activity toward CO, hydrocarbon ``HC'' oxidation, and NO reduction by CO at low temperature with high N-2 selectivity for three-way catalysis.

Aspects of tautomerism. 13. Alkaline hydrolysis of .gamma.-, .delta.-, and .epsilon.-keto esters and their desoxy analogs. Geometrical constraints on keto participation

The rates of alkaline hydrolysis of methyl &benzoylpropionate (I), methyl y-benzoylbutyrate (11) and methyll6-benzoylvalerate (In) decrease in the order I > I1 > III. Keto participation is the predominant pathway in the case of y-keto esters. Evidence has also been obtained for keto participation in the case of 6-keto esters, whereas no such evidence is available in the case of r-keto esters studied.

Dynamic structure factor across the liquid-solid interface: appearance of a delta-function elastic peak

We present a theoretical calculation of the dynamic structure factor, S(k, ω), at the liquid-solid interface for large values of the wavevector k. An analytic expression is derived which shows the evolution of the elastic peak as the solid surface is approached from the liquid side.

Characterization of protoporphyrin as the physiological regulator of delta-aminolevulinate dehydratase in Neurospora crassa

In Neurospora crassa, the activity of δ-aminolevulinate dehydratase, the second and rate-limiting enzyme of the heme-biosynthetic pathway, is low in normal cells compared to the activity detected in plants, animals and bacteria. The activity is almost undetectable when Neurospora crassa is grown under iron-deficient conditions. The enzyme activity increases strikingly on addition of iron to iron-deficient cultures. This increase can be blocked by the addition of protoporphyrin, the penultimate product of the heme-biosynthetic pathway, to the cultures. The question whether iron directly acts at the genetic level or acts merely by removing protoporphyrin, converting the latter into heme prosthetic groups of hemoproteins, has been investigated by studying the effect of inhibition of heme synthesis on the induction of δ-aminolevulinate dehydratase. It has been found that treatments with levulinic acid or cyanide which inhibit the formation of the porphyrin moiety, induce δ-aminolevulinate dehydratase, whereas treatments which inhibit at a step after protoporphyrin formation (iron-deficiency and cobalt treatment) repress the enzyme. The endogenous levels of protoporphyrin are strictly controlled: a decrease below the optimum level causing induction and an increase above the optimum level leading to repression of δ-aminolevulinate dehydratase. Levulinic acid and cyanide can induce the enzyme in iron-deficient cultures in the absence of added iron, indicating that the metal iron acts only by converting protoporphyrin to heme fixed in hemoproteins in Neurospora crassa. Therefore it is suggested that protoporphyrin is the physiological regulator of δ-aminolevulinate dehydratase in Neurospora crassa.

Economic case study of ABCD cane management practices in the Burdekin Delta region.

A case study was undertaken to determine the economic impact of a change in management class as detailed in the A, B, C and D management class framework. This document focuses on the implications of changing from D to C, C to B and B to A class management in the Burdekin Delta region and if the change is worthwhile from an economic perspective. This report provides a guide to the economic impact that may be expected when undertaking a particular change in farming practices and will ultimately lead to more informed decisions being made by key industry stakeholders. It is recognised that these management classes have certain limitations and in many cases the grouping of practices may not be reflective of the real situation. The economic case study is based on the A, B, C and D management class framework for water quality improvement developed in 2007/2008 for the Burdekin natural resource management region. The framework for the Burdekin is currently being updated to clarify some issues and incorporate new knowledge since the earlier version of the framework. However, this updated version is not yet complete and so the Paddock to Reef project has used the most current available version of the framework for the modelling and economics. As part of the project specification, sugarcane crop production data for the Burdekin Delta region was provided by the APSIM model. The information obtained from the APSIM crop modelling programme included sugarcane yields and legume grain yield (legume grain yield only applies to A class management practice). Because of the complexity involved in the economic calculations, a combination of the FEAT, PiRisk and a custom made spreadsheet was used for the economic analysis. Figures calculated in the FEAT program were transferred to the custom made spreadsheet to develop a discounted cash flow analysis. The marginal cash flow differences for each farming system were simulated over a 5-year and 10-year planning horizon to determine the Net Present Value of changing across different management practices. PiRisk was used to test uncertain parameters in the economic analysis and the potential risk associated with a change in value.