Yiguang Zhang

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Based on the measured data of spectral solar radiation in Lhasa, Tibet from 15 April to 15 October 1994, the ratio of photosynthetically active radiation (PAR) to solar global radiation was presented, i.e. ηPAR=0.439±0.014, and 1 J energy of PAR is equivalent to 4.43 mmol quantum. In the climatological estimation of Tibet Plateau, following equations can be(More)
Dynamic laser speckles contain motion information of scattering particles which can be estimated by laser speckle contrast analysis (LASCA). In this work, an entropy-based method was proposed to provide a more robust estimation of motion speed. An in vitro flow simulation experiment confirmed a simple linear relation between entropy, exposure time, and(More)
This paper introduces a notion of a random threshold directed graph, extending the work of Reilly and Scheinerman in the undirected case and closely related to random Ferrers digraphs. We begin by presenting the main definition: D is a threshold digraph provided we can find a pair of weighting functions f, g : V (D)→ R such that for distinct v, w ∈ V (D) we(More)
As a powerful tool for imaging blood flow, laser speckle contrast imaging (LSCI) has been already applied in clinical diagnosis and pre-clinical researches. In LSCI, the contrast image provides the two-dimensional blood flow distribution information with penetration depth less than 500 μm. Over the past decade, spatial, temporal and spatiotemporal(More)
Chronically monitoring cerebral activities in awake and freely moving status is very important in physiological and pathological studies. We present a novel standalone micro-imager for monitoring the cerebral blood flow (CBF) and total hemoglobin (HbT) activities in freely moving animals using the laser speckle contrast imaging (LSCI) and optical intrinsic(More)
In this paper, we report the fabrication of permalloy nanocontact structures with greatly improved surface and edge smoothness. Magnetic sputtering and thermal evaporation were used for metal film deposition, and lift-off and dry etching techniques were employed for nanocontact structure patterning. The compositional properties of the resulting nanocontacts(More)
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