Passive shimming of a 3T cryogen-free animal magnetic resonance imaging superconducting magnet with dense shim tray slots and small residual magnetic force.

Passive shimming is widely used in magnetic resonance imaging (MRI) systems due to its excellent efficacy and cost-effectiveness. However, conventional shim tray structures have difficulty in effectively adjusting magnetic field distributions under specific conditions. This limitation can lead to insufficient cancellation of harmonics and result in significant residual forces on the trays, impeding accurate placement of the trays.

A historical review and bibliometric analysis of research on estuary pollution.

A bibliometric method based on Science Citation Index-Expanded published by the Thomson Reuters was used to quantitatively assess the global estuary pollution research from 1991 to 2010. The main results were as follows: there had been a notable growth trend in publication outputs. Marine Pollution Bulletin was the most active journal.

[Ecological characteristics of phytoplankton in Shenzhen Bay].

Based on the data of surface phytoplankton investigated by Hong Kong Environmental Protection Department in Shenzhen Bay in 2006, variation characteristics of phytoplankton communities and the relationship between the phytoplankton diversity indices and environmental factors were analyzed in the present paper. Results showed that a total of 27 genera and 34 species of phytoplankton were identified. Of these, 18 were diatoms (52.