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Polycyclic aromatic hydrocarbons (PAHs) have become a major type of pollutant in urban areas and their degree of pollution and characteristics of spatial distribution differ between various regions. We conducted a comprehensive study about the concentration, source, spatial distribution, and health risk of 16 PAHs from urban to rural soils in Nanjing. The(More)
To mitigate the non-line-of-sight (NLOS) error of ultra-wideband (UWB) ranging caused by obstructions in dense multipath environments, this paper proposed a novel NLOS error mitigation method. The principles and characteristics of NLOS error are analyzed. Based on the signal propagation path loss model, the NLOS error estimation expression is deduced and(More)
Localization is essential for wireless sensor networks (WSNs). It is to determine the positions of sensor nodes based on incomplete mutual distance measurements. In this paper, to measure the accuracy of localization algorithms, a ranging error model for time of arrival (TOA) estimation is given, and the Cramer–Rao Bound (CRB) for the model is derived. Then(More)
To design a low-calculation and high-precision TOA estimation algorithm for IR-UWB ranging systems, a two-step TOA estimation method which jointly employs energy-detection (ED) and match- filtering (MF) is proposed. Based on analyzing the principles of the two-step method, it was pointed out that the success rate of DP block detection in the first step and(More)
Compressed sensing (CS) is an emerging theory that enables the reconstruction of sparse signals from a small set of random measurements. Because of the sparsity of impulse radio ultra-wideband (IR-UWB) signals in the time domain, CS makes it possible to operate at sub-Nyquist rates for IR-UWB communications where Nyquist sampling represents a formidable(More)
The influence of multicomponent additives on NO reduction by selective non-catalytic reduction process has been investigated experimentally in an electricity-heated tube reactor. The multicomponent additives are composed of two species of CO, CH(4) and H(2), and the molar ratio of their two components varies from 1/3 to 3/1. The results show that all the(More)
Rubber tree (Hevea brasiliensis Muell. Arg.) is the primarily commercial source of natural rubber in the world. Latex regeneration and duration of latex flow after tapping are the two factors that determine rubber yield of rubber tree, and exhibit a huge variation between rubber tree clones CATAS8-79 and PR107. To dissect the molecular mechanism for the(More)
Terrestrial net primary production (NPP) is an important measure of global change, and identifying the relative contributions of urbanisation and climate change to NPP is important for understanding the impact of human and natural influences on terrestrial systems and the carbon cycle. The objective of this study was to reveal how urbanisation and climate(More)