Ye Ruan

Publications (2)7.5 Total impact

• Article: Optical properties and luminescence dynamics of Eu3+-doped terbium orthophosphate nanophosphors.

  Ye Ruan, Qingbo Xiao, Wenqin Luo, Renfu Li, Xueyuan Chen
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  ABSTRACT: The development of luminescent inorganic nanocrystals (NCs) doped with rare-earth (RE) ions has attracted increasing interest owing to their distinct optical properties and versatile applications in time-resolved bioassays, multiplex biodetection, DNA hybridization and bioimaging. Hexagonal TbPO4:Eu3+ NCs (10-30 nm) were synthesized via a facile hydrothermal method assisted with oleic acid (OA) surfactants, which exhibit tunable emissions from green to red by varying the concentration of Eu3+. The Tb3+-to-Eu3+ energy transfer efficiency observed reaches up to 94%. Different from their bulk counterparts, a new interface-state band (316 nm) in addition to the commonly observed spin-forbidden 4f-5d transition band (265 nm) of Tb3+ was found to be dominant in the excitation spectrum of NCs due presumably to the formation of surface TbPO4/OA complexes, which provides an additional excitation antenna in practical utilization. Two kinds of luminescence sites of Eu3+ in TbPO4 NCs, with the site symmetry of C2 or C1, were identified based on the emission spectra at 10 K and room temperature. Furthermore, the photoluminescence (PL) dynamics of Tb3+ ions in pure TbPO4 NCs have been revealed. Compared to the exponential PL decay in bulk counterparts induced by very fast energy migration, the non-exponential decay from 5D4 of Tb3+ in TbPO4 NCs is mainly attributed to the diffusion-limited energy migration due to more rapid energy transfer from Tb3+ to defects than the energy migration among Tb3+.
  Nanotechnology 07/2011; 22(27):275701. · 3.98 Impact Factor
• Article: Major depression in Kunming: prevalence, correlates and co-morbidity in a south-western city of China.

  Jin Lu, Ye Ruan, Yueqin Huang, Jian Yao, Weimin Dang, Changqing Gao
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  ABSTRACT: Kunming is a major city in south-western China. However, until recently, no epidemiological studies have been conducted to provide a profile of major depression in south-western China. A representative sample of the Kunming general population composed of 5033 individuals aged 15 years or older was interviewed from November 2005 to January 2006 using the World Health Organization Composite International Diagnostic Interview Version 2.1 (CIDI, version 2.1) for assessment. The weighted prevalence of major depression were 1.96% (lifetime), 1.09% (12-month) and 0.93% (30-day). The correlates for reported lifetime MDD include having higher educational level, living in urban districts, being unemployed, and being divorced/widowed/separated. Major depression was significantly comorbided with DSM-IV anxiety disorders and somatization. The findings show a low prevalence rate of major depression in Kunming city. Close attention to public health approaches are required to address the relationships between social isolation, urban population, unemployed and high educational people. Resolving methodological problems may lead to more accurate prevalence estimates in future epidemiological studies.
  Journal of Affective Disorders 04/2008; 111(2-3):221-6. · 3.52 Impact Factor