Effects of envelope shape on interaural envelope delay sensitivity in acoustic and electric hearing

The envelope shape is important for the perception of interaural time difference (ITD) in the envelope as supported by the improved sensitivity for transposed tones compared to sinusoidally amplitude-modulated (SAM) tones. The present study investigated the effects of specific envelope parameters in nine normal-hearing (NH) and seven cochlear-implant (CI) listeners, using high-rate carriers with 27-Hz trapezoidal modulation. In NH listeners, increasing the off time (the silent interval in each modulation cycle) up to 12 ms, increasing the envelope slope from 6 to 8 dB/ms, and increasing the peak level improved ITD sensitivity. The combined effect of the off time and slope accounts for the gain in sensitivity for transposed tones relative to SAM tones. In CI listeners, increasing the off time up to 20 ms improved sensitivity, but increasing the slope showed no systematic effect. A 27-pulses/s electric pulse train, representing a special case of modulation with infinitely steep slopes and maximum possible off time, yielded considerably higher sensitivity compared to the best condition with trapezoidal modulation. Overall, the results of this study indicate that envelope-ITD sensitivity could be improved by using CI processing schemes that simultaneously increase the off time and the peak level of the signal envelope.     

粉粒体两相流的电容层析成象测量

粉粒体系统中的固相浓度分布的在线测量是十分困难的问题．电容层析成象技术是一种近年来发展起来的非侵入式快速浓度场测量技术．它不干扰流场，不受流动中颗粒浓度、加速度、不透明等因素的制约．本文讨论其测量原理、应用、近期进展、存在的主要问题及其解决的对策．     

ac Conductivity of mixed spinel NiAl0.7Cr0.7Fe0.6O4

ac Conductivity measurements are carried out across the metal to insulator transition in NiAl_0.7Cr_0.7Fe_0.6O₄. The low frequency data is analyzed using Summerfield scaling theory for hopping conductivity. The exponent of the scaling behavior has significantly different values in the conducting and insulating regimes. The hopping frequency and the zero frequency conductivity are found to increase with temperature, slowly in the metallic regime and rapidly in the insulating regime.     

Local canted spin behaviour in Co1.4−x Zn x Ge0.4Fe1.2O4 spinels: A macroscopic, mesoscopic and microscopic study

DC magnetization, neutron depolarization and neutron diffraction (with both polarized and unpolarized neutrons) measurements have been reported for the Co_1.1−x Zn _x Ge_0.1Fe_1.2O₁ spinels with x=0.5, 0.6 and 0.7. Neutron depolarization and neutron diffraction measurements confirm the presence of a long range ferrimagnetic ordering of the local canted spins in these ferrite samples. The observed features of low field magnetization have been explained under the framework of thermally activated domain wall movement of ferrimagnetic arrangement of local canted spins. An important role of magnetic anisotropy (due to the presence of Co²⁺ ions) in establishing the magnetic ordering and domain kinetics in these ferrites has been observed.     

Thermal behaviour of acidic salts of mixed tetravalent metals

The mixed amorphous glassy-type zirconium-titanium phosphates contain various quantities of adsorbed water per molecule unit. Pure zirconium phosphate lost the structural water in two steps. This character disappeared with increasing titanium content. However, glassy titanium phosphate lost its water in two steps at lower temperature in comparison with glassy zirconium phosphate.

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Zusammenfassung Das gemischte amorphe Zirkonium-Titan-Phosphat enthält pro Moleküleinheit verschiedene Mengen adsorbierten Wassers. Reines Zirkoniumphosphat verliert das strukturelle Wasser in zwei Schritten. Diese Eigenschaft verschwindet mit zunehmenden Titangehalt. Amorphes Titanphosphat verliert sein Wasser in zwei Schritten bei niedriger Temperatur im Vergleich zu amorphem Zirkoniumphosphat.

     

Thermal behaviour of mixed tetravalent metal salts

In contrast with the well-known zirconium and titanium phosphates, products containing these metal ions together are unknown. To investigate the thermal behaviour of such materials, samples were synthetized with various ratios of the two metal ions. The samples were identified by means of X-ray diffraction. Their thermal behaviour was investigated in the temperature interval 25–1000 °C via simultaneous TG, DTG and DTA measurements. The data obtained are presented in this paper.

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Zusammenfassung Im Gegensatz zu den wohlbekannten Zirkonium- und Titanphosphaten sind beide Metallionen gleichzeitig enthaltende Produkte unbekannt. Zur Untersuchung solcher Substanzen wurden Proben mit unterschiedlichen Mengen der beiden Metallionen gefertigt und mittels Röntgendiffraktion identifiziert. Die Proben wurden im Temperaturbereich 25–1000 °C mittels simultaner TG-, DTG- und DTA-Messungen untersucht. Die Ergebnisse werden in dieser Arbeit mitgeteilt.

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, . . - , , 25–1000°. .

     

Investigation of hydrolysis products from uranium trioxide and uranyl salts by derivatography and infrared spectroscopy

Summary It can be established from the data obtained by derivatography and infrared spectroscopy that the hydrolysis of- and amorphous UO₃ at room temperature, and that of uranyl salts in the presence of anion exchange resins, leads to compounds of UO₃ · 2H₂O composition with identical properties. This type of compound is of complex structure containing in addition to water molecules in two kinds of bonds, hydroxyl groups as well. The relative quantities of the components with different bond strengths show that the molecular structure can be described only by a trimeric formula, or by a formula corresponding to an integral multiple of a trimeric form. One kind of water has diffuse bond strength and is probably water between individual layers, while the other is a structural water of definite bond strength which may form various hydrogen bridge bonds.

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Zusammenfassung Aus derivatographischen und IR-spektroskopischen Untersuchungen ergab sich, daß die Hydrolyse von-UO₃ und amorphem UO₃ bei Zimmertemperatur sowie die Hydrolyse von Uranylsalzen in Gegenwart von Anionenaustauschharzen zu Verbindungen der Zusammensetzung UO₃ · 2H₂O führt, die identische Eigenschaften haben. Dieser Verbindungstypus hat komplexe Struktur und enthält außer Wassermolekülen mit zwei verschiedenen Bindungsarten auch Hydroxylgruppen. Die relativen Mengen der verschieden fest gebundenen Komponenten zeigen, daß die Molekülstruktur nur durch eine trimere Formel wiedergegeben werden kann. Ein Teil der Wassermoleküle ist diffus gebunden. Dabei handelt es sich wahrscheinlich um solche zwischen einzelnen Schichten. Die anderen sind strukturell gebunden und dürften verschiedene Wasserstoffbrücken ausbilden.

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Résumé On a pu établir, à partir de données obtenues par dérivatographie et spectroscopie infrarouge, que l'hydrolyse de UO₃ et amorphe à température ambiante, ainsi que celle des sels d'uranyle en présence de résines échangeuses d'anions, conduisait à des composés de composition UO₃ · 2H₂O aux propriétés identiques. Ce type de composé est de structure complexe, contenant en plus de molécules d'eau correspondant à deux sortes de liaisons, également des groupes hydroxyles. Les quantités relatives de composants possédant des forces de liaison différentes montrent que la structure moléculaire ne peut être représentée que par une formule trimère, ou par une formule correspondant à un multiple entier d'une forme trimère. L'une des sortes d'eau possède une force de liaison diffuse et il s'agit probablement d'eau placée entre des couches individuelles, tandis que l'autre est de l'eau structurale, avec une force de liaison définie, pouvant former diverses liaisons par pont d'hydrogène.

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This paper was presented at the Symposium on Analytical Chemistry held in Graz, 29th September–1st October 1965.     

A simple model for a two-stage chemical reaction with diffusion

We analyse the evolution of a two-stage chemical reaction betweentwo neighbouring plumes of reactants. Under the assumption thatthe plumes are approximately Gaussian we derive a system ofordinary differential equations for the total amount, the centroidand the variance of each reactant. We compare the solution ofthese equations with full numerical simulation of the reaction.Excellent agreement is obtained, with solution of the near-Gaussianmodel requiring considerably less computational effort thanthe full simulations. Of key importance is the yield of thereaction, and we discuss this feature in particular.     

Gas-phase deprotonation of arylalkylamines. A collision-induced dissociation study

The collision-induced dissociation (CID) of deprotonated arylalkylamines of general formula R(1)C(6)H(4)CHR(2)CH(2)NR(3)(2) (where R(1) = H, OH, F or NO(2); R(2) = H or OH; R(3) = H or CH(3)) generated by negative chemical ionization with H(2)O and D(2)O as ionizing reagents, is discussed. The negative chemical ionization mass spectra show that, in the absence of a hydroxy group in the aromatic ring, deprotonation takes place at the benzylic position whereas the proton is lost from the OH group when present. The nitro compound forms only M(-.) ions. The CID spectra of the deprotonated molecules show that fragmentations are strongly dependent on the structural features of the molecules, namely the presence or absence of substituents in the aromatic ring or aliphatic chain. Copyright 1999 John Wiley & Sons, Ltd.     

Steering in computational science: Mesoscale modelling and simulation

This paper outlines the benefits of computational steering for high performance computing applications. Lattice-Boltzmann mesoscale fluid simulations of binary and ternary amphiphilic fluids in two and three dimensions are used to illustrate the substantial improvements which computational steering offers in terms of resource efficiency and time to discover new physics. We discuss details of our current steering implementations and describe their future outlook with the advent of computational grids.