Influence of attack transient and decay times of percussive sounds on the echo threshold

2006 ◽  
Vol 120 (5) ◽  
pp. 3341-3341
Author(s):  
Hari V. Savitala ◽  
Jonas Braasch
Keyword(s):  
Decay Times ◽  
Echo Threshold

A Rheo-optical Investigation into the Viscoelastic Moduli of Acidified Milk Gel

1999 ◽  
Vol 9 (6) ◽  
pp. 246-253 ◽  
Author(s):  
E. O. Arikainen ◽  
J. C. Earnshaw ◽  
A. Wehling ◽  
E. Waghorne
Keyword(s):  
Correlation Function ◽  
Mean Square Displacement ◽  
Slow Motion ◽  
Casein Micelle ◽  
Optical Investigation ◽  
Viscoelastic Moduli ◽  
Decay Times ◽  
Delay Times ◽  
Intensity Correlation Function ◽  
Viscoelastic Modulus

Abstract Diffusing wave spectroscopy (DWS) in the backscattering geometry was employed to observe the evolution of the intensity correlation function during the acidification of skimmed milk by gluconic-δ-lactone (GDL). At the stage when the formation of casein particle gel is largely complete the correlation function at shorter decay times reveals the local structural arrest of the casein micelles, whereas at longer delay times it illustrates the hindered slow motion of casein micelle aggregates. We use the principles of the approach suggested by Mason, Gang and Weitz, linking the optically measured mean square displacement, <Δr2(t)>, of the microscopic particles in a dense colloid to its viscoelastic properties, to provide an estimate of the frequency dependent viscoelastic modulus of the acidified milk gel (AMG). We compare the viscoelastic moduli measured by the conventional mechanical rheometry with the optically measured ones. The results of the two different experimental methods are found to be in reasonable agreement.

scholarly journals High performing flexible optoelectronic devices using thin films of topological insulator

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Animesh Pandey ◽  
Reena Yadav ◽  
Mandeep Kaur ◽  
Preetam Singh ◽  
Anurag Gupta ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Nonlinear Optical ◽  
Near Infrared ◽  
Optoelectronic Devices ◽  
Nonlinear Optical Properties ◽  
Metallic Surface ◽  
Strong Light ◽  
High Performing ◽  
Decay Times

AbstractTopological insulators (TIs) possess exciting nonlinear optical properties due to presence of metallic surface states with the Dirac fermions and are predicted as a promising material for broadspectral phodotection ranging from UV (ultraviolet) to deep IR (infrared) or terahertz range. The recent experimental reports demonstrating nonlinear optical properties are mostly carried out on non-flexible substrates and there is a huge demand for the fabrication of high performing flexible optoelectronic devices using new exotic materials due to their potential applications in wearable devices, communications, sensors, imaging etc. Here first time we integrate the thin films of TIs (Bi2Te3) with the flexible PET (polyethylene terephthalate) substrate and report the strong light absorption properties in these devices. Owing to small band gap material, evolving bulk and gapless surface state conduction, we observe high responsivity and detectivity at NIR (near infrared) wavelengths (39 A/W, 6.1 × 108 Jones for 1064 nm and 58 A/W, 6.1 × 108 Jones for 1550 nm). TIs based flexible devices show that photocurrent is linearly dependent on the incident laser power and applied bias voltage. Devices also show very fast response and decay times. Thus we believe that the superior optoelectronic properties reported here pave the way for making TIs based flexible optoelectronic devices.

Phosphorescence of naphthalene-labelled colloidal polymer particles. The α-methyl relaxation of one microphase in a multicomponent material

1985 ◽  
Vol 63 (1) ◽  
pp. 129-133 ◽  
Author(s):  
Mitchell A. Winnik ◽  
Onder Pekcan ◽  
M. D. Croucher
Keyword(s):  
Decay Process ◽  
Relaxation Processes ◽  
Pure Pmma ◽  
Phosphorescence Quenching ◽  
Complex Morphology ◽  
Freeze Dried ◽  
Decay Times ◽  
Powder Samples ◽  
Pmma Particles ◽  
Multicomponent Material

Nonaqueous dispersions of poly(methyl methacrylate) (PMMA) particles, sterically stabilized with polyisobutylene (PIB), were prepared with naphthalene (N) groups covalently incorporated into the PMMA chains. These materials have a complex morphology of phase-separated PMMA and PIB microdomains, with the N groups in the PMMA microphases. The phosphorescence intensity and decay times of the N groups were measured as a function of temperature over the range 77–295 K for dispersions in methylcyclohexane and for freeze-dried powder samples. An Arrhenius treatment of the radiationlcss decay rate showed a change in slope at −35 °C. The activation energy for the radiationless decay process is 3.8 kcal/mol in the −35 – +22 °C temperature region, identical to that found for pure PMMA by nmr for chain motion associated with the a-methyl relaxation process. We believe that the phosphorescence experiment is sensitive to the diffusion of oxygen and other impurities in the sample. These rates increase as the temperature is raised, enhancing the rate of phosphorescence quenching. These experiments indicate that phosphorescence measurements on labelled samples are suitable for studying relaxation processes within individual microphases of a polyphasic composite material.

Influence of Transparent Electrodes on Image Sensor Performance

1985 ◽  
Vol 49 ◽  
Author(s):  
K. Kempter ◽  
H. Wieczrek ◽  
M. Hoheisel
Keyword(s):  
Response Times ◽  
Image Sensor ◽  
Image Sensors ◽  
Transparent Electrodes ◽  
Sensor Performance ◽  
Decay Times ◽  
Sensor Cell ◽  
Photocurrent Decay

AbstractThe short response times required for image sensors demand blocking contacts at the sensor cell. It was found that the junctions between transparent electrodes (ITO or a thin palladium film) and the metallic back electrode with a-Si:H form blocking contacts yielding photocurrent decay times of the order of some microseconds. The two different time regimes observed for the decay are interpreted as being limited by the drift and the release of holes respectively.

Synthesis and Photophysical Properties of a Conformationally Flexible Mixed Porphyrin Star-Pentamer

2009 ◽  
Vol 62 (7) ◽  
pp. 692 ◽  
Author(s):  
Toby D. M. Bell ◽  
Sheshanath V. Bhosale ◽  
Kenneth P. Ghiggino ◽  
Steven J. Langford ◽  
Clint P. Woodward
Keyword(s):  
Energy Transfer ◽  
Photophysical Properties ◽  
Fluorescence Decay ◽  
High Yield ◽  
Free Base ◽  
Time Resolved ◽  
Zinc Porphyrin ◽  
Relative Contribution ◽  
Synthetic Strategy ◽  
Decay Times

The synthesis of a porphyrin star-pentamer bearing a free-base porphyrin core and four zinc(ii) metalloporphyrins, which are tethered by a conformationally flexible linker about the central porphyrin’s antipody, is described. The synthetic strategy is highlighted by the use of olefin cross metathesis to link the five chromophores together in a directed fashion in high yield. Photoexcitation into the Soret absorption band of the zinc porphyrin chromophores at 425 nm leads to a substantial enhancement of central free-base porphyrin fluorescence, indicating energy transfer from the photoexcited zinc porphyrin (outer periphery) to central free-base porphyrin. Time-resolved fluorescence decay profiles required three exponential decay components for satisfactory fitting. These are attributed to emission from the central free-base porphyrin and to two different rates of energy transfer from the zinc porphyrins to the free-base porphyrin. The faster of these decay components equates to an energy-transfer rate constant of 3.7 × 109 s–1 and an efficiency of 83%, whereas the other is essentially unquenched with respect to reported values for zinc porphyrin fluorescence decay times. The relative contribution of these two components to the initial fluorescence decay is ~3:2, similar to the 5:4 ratio of cis and trans geometric isomers present in the pentamer.

scholarly journals Apparent lack of physical or functional interaction between CaV1.1 and its distal C terminus

2015 ◽  
Vol 145 (4) ◽  
pp. 303-314 ◽  
Author(s):  
Joshua D. Ohrtman ◽  
Christin F. Romberg ◽  
Ong Moua ◽  
Roger A. Bannister ◽  
S. Rock Levinson ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fluorescent Protein ◽  
Yellow Fluorescent Protein ◽  
Channel Activity ◽  
Functional Interaction ◽  
Adult Skeletal Muscle ◽  
Apparent Lack ◽  
Terminal Domain ◽  
C Terminus ◽  
Decay Times

CaV1.1 acts as both the voltage sensor that triggers excitation–contraction coupling in skeletal muscle and as an L-type Ca2+ channel. It has been proposed that, after its posttranslational cleavage, the distal C terminus of CaV1.1 remains noncovalently associated with proximal CaV1.1, and that tethering of protein kinase A to the distal C terminus is required for depolarization-induced potentiation of L-type Ca2+ current in skeletal muscle. Here, we report that association of the distal C terminus with proximal CaV1.1 cannot be detected by either immunoprecipitation of mouse skeletal muscle or by colocalized fluorescence after expression in adult skeletal muscle fibers of a CaV1.1 construct labeled with yellow fluorescent protein (YFP) and cyan fluorescent protein on the N and C termini, respectively. We found that L-type Ca2+ channel activity was similar after expression of constructs that either did (YFP-CaV1.11860) or did not (YFP-CaV1.11666) contain coding sequence for the distal C-terminal domain in dysgenic myotubes null for endogenous CaV1.1. Furthermore, in response to strong (up to 90 mV) or long-lasting prepulses (up to 200 ms), tail current amplitudes and decay times were equally increased in dysgenic myotubes expressing either YFP-CaV1.11860 or YFP-CaV1.11666, suggesting that the distal C-terminal domain was not required for depolarization-induced potentiation. Thus, our experiments do not support the existence of either biochemical or functional interactions between proximal CaV1.1 and the distal C terminus.

scholarly journals Androgens Modulate NMDA Receptor–Mediated EPSCs in the Zebra Finch Song System

1999 ◽  
Vol 82 (5) ◽  
pp. 2221-2234 ◽  
Author(s):  
Stephanie A. White ◽  
Frederick S. Livingston ◽  
Richard Mooney
Keyword(s):  
Nmda Receptor ◽  
Synaptic Transmission ◽  
Time Course ◽  
Song Learning ◽  
Lateral Part ◽  
Spine Density ◽  
Song System ◽  
Decay Times ◽  
Soma Size

Androgens potently regulate the development of learned vocalizations of songbirds. We sought to determine whether one action of androgens is to functionally modulate the development of synaptic transmission in two brain nuclei, the lateral part of the magnocellular nucleus of the anterior neostriatum (LMAN) and the robust nucleus of the archistriatum (RA), that are critical for song learning and production. We focused on N-methyl-d-aspartate–excitatory postsynaptic currents (NMDA-EPSCs), because NMDA receptor activity in LMAN is crucial to song learning, and because the LMAN synapses onto RA neurons are almost entirely mediated by NMDA receptors. Whole cell recordings from in vitro brain slice preparations revealed that the time course of NMDA-EPSCs was developmentally regulated in RA, as had been shown previously for LMAN. Specifically, in both nuclei, NMDA-EPSCs become faster over development. We found that this developmental transition can be modulated by androgens, because testosterone treatment of young animals caused NMDA-EPSCs in LMAN and RA to become prematurely fast. These androgen-induced effects were limited to fledgling and juvenile periods and were spatially restricted, in that androgens did not accelerate developmental changes in NMDA-EPSCs recorded in a nonsong area, the Wulst. To determine whether androgens had additional effects on LMAN or RA neurons, we examined several other physiological and morphological parameters. In LMAN, testosterone affected α-amino-3-hydroxy-5-methyl-4-isoxazoleproprianate–EPSC (AMPA-EPSC) decay times and the ratio of peak synaptic glutamate to AMPA currents, as well as dendritic length and spine density but did not alter soma size or dendritic complexity. In contrast, testosterone did not affect any of these parameters in RA, which demonstrates that exogenous androgens can have selective actions on different song system neurons. These data are the first evidence for any effect of sex steroids on synaptic transmission within the song system. Our results support the idea that endogenous androgens limit sensitive periods for song learning by functionally altering synaptic transmission in song nuclei.

scholarly journals Highly efficient self-powered perovskite photodiode with an electron-blocking hole-transport NiOx layer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Amir Muhammad Afzal ◽  
In-Gon Bae ◽  
Yushika Aggarwal ◽  
Jaewoo Park ◽  
Hye-Ryeon Jeong ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Bias Voltage ◽  
High Performance ◽  
Hole Transport ◽  
Transport Layer ◽  
Hole Transport Layer ◽  
Zero Bias ◽  
Decay Times ◽  
Order Of Magnitude ◽  
Self Powered

AbstractHybrid organic–inorganic perovskite materials provide noteworthy compact systems that could offer ground-breaking architectures for dynamic operations and advanced engineering in high-performance energy-harvesting optoelectronic devices. Here, we demonstrate a highly effective self-powered perovskite-based photodiode with an electron-blocking hole-transport layer (NiOx). A high value of responsivity (R = 360 mA W−1) with good detectivity (D = 2.1 × 1011 Jones) and external quantum efficiency (EQE = 76.5%) is achieved due to the excellent interface quality and suppression of the dark current at zero bias voltage owing to the NiOx layer, providing outcomes one order of magnitude higher than values currently in the literature. Meanwhile, the value of R is progressively increased to 428 mA W−1 with D = 3.6 × 1011 Jones and EQE = 77% at a bias voltage of − 1.0 V. With a diode model, we also attained a high value of the built-in potential with the NiOx layer, which is a direct signature of the improvement of the charge-selecting characteristics of the NiOx layer. We also observed fast rise and decay times of approximately 0.9 and 1.8 ms, respectively, at zero bias voltage. Hence, these astonishing results based on the perovskite active layer together with the charge-selective NiOx layer provide a platform on which to realise high-performance self-powered photodiode as well as energy-harvesting devices in the field of optoelectronics.

Electro-optical property of polymerized liquid crystal devices using linearly polarized UV irradiation

2021 ◽  
Author(s):  
Masahiro Ito ◽  
Kazuma Kajiwara ◽  
Kohki Takatoh
Keyword(s):  
Liquid Crystal ◽  
Uv Light ◽  
Strong Dependence ◽  
Fast Response ◽  
Alignment Layer ◽  
Liquid Crystal Devices ◽  
Decay Times ◽  
Linearly Polarized ◽  
Reactive Mesogens ◽  
Strong Anchoring

Abstract Display characteristics have a fairly strong dependence on the configuration of the liquid crystal (LC) molecules and interactions between the LC molecules and the alignment layer surface. To obtain LC devices with a fast response, the usage of reactive mesogens (RMs) have been studied. RMs polymerize in the vicinity of the alignment layer. We assessed the effectiveness of linearly polarized UV light for polymer formation. Three kinds of UV light, namely (i)non-polarized (ii)parallel to, and (iii)perpendicular to the rubbing direction, were used to irradiate LC cells with RM concentrations of 5wt% and 10wt%. For both RM concentrations, LC devices using LPUV parallel to the rubbing direction yielded the shortest decay times. SEM observation revealed that the fibrils polymerized linearly in the same direction on using LPUV parallel to the rubbing direction. The decay time was presumably shortened by the strong anchoring force and high alignment ability of the linear fibrils.

Properties of spontaneous inhibitory synaptic currents in cultured rat spinal cord and medullary neurons

1996 ◽  
Vol 76 (1) ◽  
pp. 448-460 ◽  
Author(s):  
C. A. Lewis ◽  
D. S. Faber
Keyword(s):  
Spinal Cord ◽  
Time Constant ◽  
Decay Time ◽  
Cultured Cells ◽  
Decay Time Constant ◽  
Inhibitory Synapses ◽  
Gamma Aminobutyric Acid ◽  
Postsynaptic Receptor ◽  
Decay Times ◽  
Medullary Neurons

1. To identify the type(s) and properties of inhibitory postsynaptic receptor(s) involved in synaptic transmission in cultured rat embryonic spinal cord and medullary neurons, we have used whole cell patch-clamp techniques to record miniature inhibitory postsynaptic currents (mIPSCs) in the presence of tetrodotoxin, DL-2-amino-5-phosphonovaleric acid, and 6-cyano-7-nitroquinoxaline-2,3-dione. 2. The mIPSCs recorded from both spinal cord and medullary neurons had skewed amplitude distributions. 3. The glycinergic antagonist strychnine and the GABAergic antagonist bicuculline each decreased both the frequency and mean peak amplitudes of mIPSCs. We conclude that both glycine and gamma-aminobutyric acid (GABA) are neurotransmitters at inhibitory synapses in our cultured cells. 4. Most (approximately 96-97%) mIPSCs decay with single-exponential time constants, and decay time distributions were consistently best fitted by the sum of four Gaussians with decay constants as follows: D1 = 5.8 +/- 0.1 (SE) ms (n = 63), D2 = 12.2 +/- 0.2 ms (n = 61), D3 = 23.2 +/- 0.4 ms (n = 54), and D4 = 44.7 +/- 1.0 ms (n = 57). We conclude that the four classes of decay times represent kinetically different inhibitory postsynaptic receptor populations. 5. Strychnine and bicuculline usually had one of two different effects on the mIPSC decay time constant distributions; either selective decreases in the frequency of mIPSCs with decay times in certain classes (i.e., the D1 class was reduced by bicuculline, the D2 class by strychnine, and the D3 and D4 classes by both antagonists) or a nonselective depression in the frequency of mIPSCs with decay times in all four classes. The particular effect observed in a given neuron was correlated with the presence or absence of ATP and guanosine 5'-triphosphate (GTP) in the patch pipette. Namely, in 71% of the antagonist applications where the pipette contained ATP and GTP, the result was a nonselective decrease in mIPSCs in all decay time constant classes. Conversely, in 54% of the antagonist applications in their absence, the result was a selective decrease in the frequency of mIPSCs in specific decay time constant classes. 6. In some experiments, mIPSCs reappeared in antagonist solution after an essentially complete block. Recovery from block in the continued presence of antagonist was never observed in the absence of ATP and GTP (8 neurons), and, at the same time, 5 of 9 neurons patched with ATP and GTP in the pipette did show recovery (56%).

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