Size distribution and diffuse pollution impacts of PAHs in street dust in urban streams in the Yangtze River Delta

Particles of dust washed off streets by stormwater are an important pathway of polyaromatic hydrocarbons (PAHs) into urban streams. This article presented a comprehensive assessment of the size distribution of PAHs in street dust particles, the potential risks of the particles in urban streams, and the sources and sinks of PAHs in the stream network. This assessment was based on measurements of 16 PAHs from the USEPA priority list in street dust particles and river sediments in Xincheng, China. The content of total PAHs ranged from 1629 to 8986 μg/kg in street dust particles, where smaller particles have a higher concentrations. Approximately 55% of the total PAHs were associated with particles less than 250 μm which accounted for 40% of the total mass of street dust. The PAH quantities increased from 2.41 to 46.86 μg/m2 in the sequence of new residential, rising through main roads, old town residential, commercial and industrial areas. The sediments in stream reaches in town were found to be sinks for street dust particle PAHs. The research findings suggested that particle size, land use and the hydrological conditions in the stream network were the factors which most influenced the total loads of PAH in the receiving water bodies.<br/

Characterization of ultrathin InSb nanocrystals film deposited on SiO2/Si substrate

Recently, solid-phase recrystallization of ultrathin indium antimonide nanocrystals (InSb NCs (films grown on SiO2/Si substrate is very attractive, because of the rapid development of thermal annealing technique. In this study, the recrystallization behavior of 35 nm indium antimonide film was studied. Through X-ray diffraction (XRD) analysis, it is demonstrated that the InSb film is composed of nanocrystals after high temperature rapid thermal annealing. Scanning electron microscopy shows that the film has a smooth surface and is composed of tightly packed spherical grains, the average grain size is about 12.3 nm according to XRD results. The optical bandgap of the InSb NCs film analyzed by Fourier Transform infrared spectroscopy measurement is around 0.26 eV. According to the current-voltage characteristics of the InSb NCs/SiO2/p-Si heterojunction, the film has the rectifying behavior and the turn-on voltage value is near 1 V

Price volatility characteristics and policy implications of freshwater fish in China

The fisheries industry in China is experiencing rapid growth, but it is also encountering the challenge of frequent fluctuations in aquatic product prices. Freshwater fish aquaculture plays a crucial role in China's fisheries industry. Analyzing the characteristics of price volatility in freshwater fish is crucial to ensure a stable supply of aquatic products and promote sustainable fisheries industry development. This study focuses on four freshwater fish species, namely crucian carp, grass carp, silver carp, and carp, to analyze the price volatility characteristics of freshwater fish in China from 2006 to 2022. The study uses the price decomposition method and the ARCH model. The results indicate that, from the perspective of dominant characteristics of price volatility, the prices of freshwater fish display periodic volatility with an overall upward trend, as well as significant seasonal and random variations. From the perspective of recessive price volatility characteristics, the price volatility of freshwater fish exhibits clustering and asymmetry. This indicates that the price volatility of freshwater fish is influenced by previous price volatility. Positive news has a greater impact on the price volatility of freshwater fish than negative news. Out of the four freshwater fish species, only the price of crucian carp is characterized by high-risk and high-return volatility