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排序方式: 共有714条查询结果,搜索用时 15 毫秒
711.
A food recording electronic device to simplify the collection of dietary data is described. The need for a subject to maintain a quantitative account of food intake, and for a dietitian to subsequently code this record prior to computer analysis, are both eliminated using this approach. In combination with an electronic kitchen balance, the recorder, which is based upon a single-board computer (SBC) and special keyboard, enables the weight, food type and time of consumption of each food to be recorded automatically in response to simple key entry. The resident program, transparent to the user, allows data from surveys lasting up to three weeks to be stored for subsequent serial downloading to a host computer. 相似文献
712.
RI Damper 《Canadian Metallurgical Quarterly》1976,15(6):488-500
Subjects were presented with an initially stationary binaural image formed by the fusion of two identical pulses, without interaural time difference (ITD), at the two ears. The image was then made to traverse the subject's auditory perceptual space by introducing ITD, varying linearly with time, under computer control. The direction of movement, i.e. towards the right or left ear, could be reversed by the listener, by pressing a button. Subjects were requested to keep the image central, by pressing the button when they judged that deviation from subjective centre had occurred. Experiments of this type can be considered as analogous to Békésy audiometry, where the subject automatically traces his threshold of hearing, in that here the listener traces out his auditory perceptual centre as it varies with time. Hence, equivalent analyses to those employed for Békésy audiometry are possible. Subsequent to the initial part of the experiment, an additional pulse was added to one channel, preceding the original pulse, to form a pulse pair. The monaural masking of the original pulse by this additional pulse thus acts to shift the pre-existing binaural image. The effect of varying the amplitude and onset time of the masking pulse, relative to the original pulse, on the Békésy-type trace was examined. 相似文献
713.
Hayward G Benny G Banks R Galbraith W 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2000,47(6):1438-1447
This paper describes the evaluation of the radiation field characteristics of PVDF membrane transducers, whereby the active area is defined by an appropriate electrode pattern when operating into air. Measurement, including conventional scanning of the fields and laser vibrometry, is supplemented by finite element modeling over the frequency range 500 kHz to 1.1 MHz. Contrary to expectation, the surface displacements are nonuniform, giving rise to premature axial focusing of the field. This is shown to be caused by generation of the zero order symmetrical Lamb wave, arising from the electric field discontinuity at the electrode boundary of the transducer. 相似文献
714.
Nils Dessmann Nguyen H.Le Viktoria Eless Steven Chick Kamyar Saeedi Alberto Perez-Delgado Sergey G.Pavlov Alexander F.G.van der Meer Konstantin L.Litvinenko Ian Galbraith Nikolay V.Abrosimov Helge Riemann Carl R.Pidgeon Gabriel Aeppli Britta Redlich Benedict N.Murdin 《光:科学与应用(英文版)》2021,10(5):806-811
Third-order non-linearities are important because they allow control over light pulses in ubiquitous high-quality centro-symmetric materials like silicon and si... 相似文献