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21.
Krumbholz K Maresh K Tomlinson J Patterson RD Seither-Preisler A Lütkenhöner B 《The Journal of the Acoustical Society of America》2004,115(4):1696-1704
This study investigates whether the salience of the pitch associated with a single reflection of a broadband sound, such as noise, is determined by the monaural information mediated by the stimuli at the two ears, or by the relative locations of the primary sound and the reflection. Pitch strength was measured as a function of the reflection delay and the lateral displacement between the primary sound and the reflection. Thereby, lateral displacement was produced by means of interaural time differences (ITDs) in experiment 1 and interaural level differences (ILDs) in experiment 3. The results from both experiments are in accordance with the assumption that the strength of the pitch associated with a reflection is based on a central average of the internal representations of the stimuli at the two ears. This notion was corroborated by experiment 2, which showed that the results from experiment 1 could be mimicked by simply adding the stimuli from the two ears and presenting the merged stimulus identically to both ears. 相似文献
22.
A. Borowiec M. MacKenzie G.C. Weatherly H.K. Haugen 《Applied Physics A: Materials Science & Processing》2003,76(2):201-207
The final state of the material resulting from laser irradiation of silicon using 130 fs pulses at 790 nm was studied using
a number of techniques including scanning and transmission electron microscopies, as well as atomic force microscopy. Structural
details and the level of damage to the nearby solid following irradiation were characterized and are discussed in the context
of recent dynamical studies.
Received: 28 September 2001 / Accepted: 3 March 2002 / Published online: 19 July 2002
RID="*"
ID="*"Department of Engineering Physics, McMaster University, Hamilton, Ontario, L8S 4M1, Canada
RID="**"
ID="**"Corresponding author. Fax: +1-905/521-2773, E-mail: borowia@mcmaster.ca
RID="***"
ID="***"Present address: Department of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
RID="****"
ID="****"Department of Materials Science and the CEMD, McMaster University, Hamilton, Ontario, L8S 4M1, Canada
RID="*****"
ID="*****"Departments of Engineering Physics, and Physics and Astronomy, and the CEMD, McMaster University, Hamilton, Ontario,
L8S 4M1, Canada 相似文献
23.
van Delden RA Koumura N Schoevaars A Meetsma A Feringa BL 《Organic & biomolecular chemistry》2003,1(1):33-35
A newly designed donor-acceptor substituted molecular motor 1 allows unidirectional rotation driven by visible light and shows some unique photophysical properties. 相似文献
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R. Mark Nicoll Sally A. Hindle Grant MacKenzie Ian H. Hillier Neil A. Burton 《Theoretical chemistry accounts》2001,106(1-2):105-112
26.
Annemarie Huijser Dr. Alessandro Pezzella Dr. Jonas K. Hannestad Lucia Panzella Dr. Alessandra Napolitano Prof. Marco d'Ischia Prof. Villy Sundström Prof. 《Chemphyschem》2010,11(11):2424-2431
The UV‐dissipative mechanisms of the eumelanin building block 5,6‐dihydroxyindole‐2‐carboxylic acid (DHICA) and the 4,7‐dideutero derivative (DHICA‐d2) in buffered H2O or D2O have been characterized by using ultrafast time‐resolved fluorescence spectroscopy. Excitation of the carboxylate anion form, the dominating state at neutral pH, leads to dual fluorescence. The band peaking at λ=378 nm is caused by emission from the excited initial geometry. The second band around λ=450 nm is owed to a complex formed between the mono‐anion and specific buffer components. In the absence of complex formation, the mono‐anion solely decays non‐radiatively or by emission with a lifetime of about 2.1 ns. Excitation of the neutral carboxylic acid state, which dominates at acidic pH, leads to a weak emission around λ=427 nm with a short lifetime of 240 ps. This emission originates from the zwitterionic state, formed upon excitation of the neutral state by sub‐ps excited‐state intramolecular proton transfer (ESIPT) between the carboxylic acid group and the indole nitrogen. Future studies will unravel whether this also occurs in larger building blocks and ESIPT is a built‐in photoprotective mechanism in epidermal eumelanin. 相似文献
27.
Guarato F Jakobsen L Vanderelst D Surlykke A Hallam J 《The Journal of the Acoustical Society of America》2011,129(2):1046-1058
Taking into account directivity of real sound sources makes it possible to try solving an interesting and biologically relevant problem: estimating the orientation in three-dimensional space of a directional sound source. The source, of known directivity, produces a broadband signal (in the ultrasonic range, in this application) that is recorded by microphones whose position with respect to source is known. An analytical method to process the recorded signals and estimate source orientation is developed in this paper. Experiments testing method performance in estimating source orientation were performed both in a laboratory environment with a Polaroid transducer as source and in a flight room with a Myotis daubentonii bat. In the first case, results showed the estimation method to be accurate and pointed out its limitations. The latter case is significant as an example biological application of the method for extracting behavioral features from bats; results are compared with alternative calculations based on microphone root-mean-square (rms)-pressure values. 相似文献
28.
Borka Kovacevik Annemarie Wagner Johan Boman Jens Laursen Jan B. C. Pettersson 《X射线光谱测定》2011,40(4):280-288
Aerosol samples were collected at an urban background site in Skopje, Former Yugoslavic Republic of Macedonia, during four measurement campaigns from December 2006 to October 2007. An impactor was used to collect particulate matter (PM2.5) aerosol particles and the samples were analyzed for the concentrations of particulate mass, black carbon (BC), and 17 elements. The 12‐h average PM2.5 concentrations varied in the range 10–140 µg m?3 with the highest concentrations measured during wintertime pollution episodes and during the summer period. Pair‐wise correlations and crustal enrichment were studied and the data set was analyzed by factor analysis and positive matrix factorization. Major aerosol components were identified as mineral dust (main observed tracers Si, K, Ca, Ti, Fe, Sr, and Rb), combustion (BC, S, K, V, and Ni), traffic‐related aerosol (Pb and Zn), and secondary sulfate combined with mineral dust. Combustion sources dominated during wintertime and were likely due to heavy oil combustion, biomass burning, and other industrial activities within the city area. Mineral dust was observed throughout the year, but the concentrations peaked during the unusually hot and dry summer of 2007. It is concluded that Skopje suffers from serious air pollution due to central and residential heating, the transport sector, and industrial activities within the city, and contributions from mineral dust increase the PM2.5 concentrations under dry periods. Topography and meteorological conditions aggravate the problems and make the air quality comparable with the conditions in other highly polluted cities in Southern Europe and worldwide. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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