[Research progress in using functional near-infrared spectroscopy for monitoring depth of anesthesia].

Intra-operation monitoring depth of anesthesia is an important method to insure the quality and safety of clinical anesthesia. As a noninvasive brain function monitoring technology, functional near-infrared spectroscopy can provide objective and reliable brain activity monitoring and imaging in real time. The characteristic of this technique is highly suitable for interrelated research on depth of anesthesia monitoring. The present paper briefly introduced the fundamental and instruments of functional near-infrared spectroscopy, reviewed the current situation about the application of functional near-infrared spectroscopy in research on depth of anesthesia monitoring, pointed out the possible way of using functional near-infrared spectroscopy in depth of anesthesia monitoring research, and expounded the unsolved problems and future prospects.

Luminescence efficiency enhancement of BaZr(BO3)2:Eu with Si or Al addition.

Si4+ and Al3+ doped BaZr(BO3)2:Eu phosphors were prepared by solidstate reaction. BaZr(BO3)2:Eu3+, BaZr(BO3)2:Eu3+, Si4+ and BaZr(BO3)2:Eu3+, Al3+ were characterized by X-ray diffraction spectra (XRD) and photoluminescence spectra. After codoped with Si or Al, the charge-transfer state (CTS) band of Eu3+-O(2-) shows blue shift accompanied by increasing intensity due to shorter ionic radius and stronger electro negativity of Si or Al compared with Zr4+. The high value of asymmetric ratio R(2-1) and omega2 of BaZr(BO3)2:Eu3+ with Si or Al codoping indicates a less symmetrical local structure of Eu3+. This implies that the quantum efficiencies of the 5D0 level of these complexes can be enhanced by doping with Si and Al respectively. Calculation of the Judd-Ofelt parameters of Eu3+ under different crystal fields gives similar results.

Luminescence of er doped ZnS quantum dots excited by infrared lasers.

ZnS:Er quantum dots were prepared in aqueous medium from readily available precursors. The construction, morphology and luminescence properties of the ZnS:Er quantum dots were evaluated by X-ray diffraction (XRD), transmission electron microscopy (TEM), and photoluminescence spectra. The average particle size was calculated using the Scherrer formula to be 4 nm, which is also observed from high resolution transmission electron microscopy (HRTEM) image. Different laser wavelengths at 976 +/- 2 nm and 1480 nm were utilized as the excitation source. ZnS:Er quantum dots had a fluorescence spectrum in 1550 nm region through the 4I13/2 --> 4I15/2 transition. Furthermore, intensity increased with increasing excitation intensity and dopant concentration. The reason for the photoluminescence spectra broadening is discussed. It is because the energy levels of Er3+ are split by a coulombic interaction between electrons, including spin correction and spin-orbit coupling, and eventually by the Stark effect due to ZnS QDs crystal field and local coordination.