高亮度白色激光光源提升远光性能的研究

激光照明技术具有高亮度、光效高等特性,是下一代固态照明的理想光源。通过高功率的半导体蓝色激光泵浦激发含Ce:YAG (Y3AL5O12:Ce3+)荧光粉的光色转换材料去获取高亮度白色激光光源。但是入射的高功率激光是直接聚焦在光色转换材料上的,对其耐热性、适用高能量密度光激发等特性提出了较高的要求。本文采用丝网印刷法、真空烧结在蓝宝石衬底上制备了高性能的Ce:YAG荧光陶瓷涂层,并和商业蓝色激光二极管进行了器件封装,获得了142 lm/W的光效。最后在整车上集成了开发的激光辅助远光功能模块的激光大灯,实验结果表明,高亮度的白色激光光源可提升夜间远光的可视距离至600 m,极大的提升了夜间驾驶安全性。

基于RGB三基色半导体激光的高功率白激光光源

基于红绿蓝(RGB)三基色直接半导体激光器合成的白激光光源具有转换效率高、显色指数好、输出功率高等优点,是新一代的理想照明光源和显示光源之一。基于RGB三基色半导体激光器件,通过空间合束、波长合束等,三基色光耦合进单光纤,光纤输出合束光功率超过100 W。根据色度学原理进行颜色功率配比,获得了功率达63 W、色温为5 710 K的白光输出,与标准白光D 65相比色温偏差小于12.2%。在此基础上,调整红色激光输出功率,获得了功率达58.4 W、色温为6 480 K的白光输出,与标准白光D 65相比色温偏差小于3.08%。基于该光源,通过调整激光功率配比,可实现不同色温的合束激光输出。

Ameliorated stress related proteins are associated with improved cardiac function by sarcoplasmic reticulum calcium ATPase gene transfer in heart failure

Background Previous studies showed that overexpression of sarco-endoplasmic retieulum calcium ATPase （SERCA2a） in a variety of heart failure （HF） models was associated with greatly enhanced cardiac performance. However, it still undefined the effect of SERCA2a overexpression on the systemic inflammatory response and neuro-hormonal factors. Methods A rapid right ventricular pacing model of experimental HF was used in beagles. Then the animals underwent recombinant adeno-associated vires 1 （rAAV1） mediated gene trans- fection by direct intra-myocardium injection. HF animals were randomized to receive the SERCA2a gene, enhanced green fluorescent protein （control） gene, or equivalent phosphate buffered saline. Thirty days after gene delivery, the cardiac function was evaluated by echocardiographic testing. The protein level of SERCA2a was measured by western blotting. The proteomic analysis of left ventricular （LV） sample was determined using two-dimensional （2-D） gel el^ctrophoresis and MALDI-TOF-MS. The serum levels of the systemic inflammatory and neuro-hormonal factors were assayed using radioimmunoassay kits. Results The cardiac function improved after SERCA- 2a gene transfer due to the significantly increased SERCA2a protein level. Beagles treated with SERCA2a had significantly decreased serum levels of the inflammatory markers （interleukin-6 and tumor necrosis factor-a） and neuro-hormonal factors （brain natriuretic peptide, endothelin-1 and angiotensin II） compared with HF animals. The myocardial proteomic analysis showed that haptoglobin heavy chain, heat shock protein （alpha-crystallin-related, B6） were down-regulated, and galectin-1 was up-regulated in SERCA2a group compared with HF group, companied by up-regulated contractile proteins and NADH dehydrogenase. Conclusions These findings demonstrate that regional intramyocardial injections of rAAV 1-SERCA2a vectors may improve global LV function, correlating with reverse activation of the systemic inflammatory, excessive neuroendocrine factors and the stress-associated myocardial proteins, suggesting that the beneficial effects of SERCA2a gene transfer may involve the attenuation of stress-associated reaction.

Monomeric type I and type III transforming growth factor-β receptors and their dimerization revealed by single-molecule imaging

Transforming growth factor-β （TGF-β） binds with two transmembrane serine/threonine kinase receptors, type Ⅱ （TβRII） and type Ⅰ receptors （TβRⅠ）, and one accessory receptor, type Ⅲ receptor （TβRⅢ）, to transduce signals across cell membranes. Previous biochemical studies suggested that TβRI and TβRIII are preexisted homo-dimers. Using single-molecule microscopy to image green fluorescent protein-labeled membrane proteins, for the first time we have demonstrated that TβRI and TβRⅢ could exist as monomers at a low expression level. Upon TGF-β1 stimu- lation, TβRI follows the general ligand-induced receptor dimerization model for activation, but this process is TβRⅡ- dependent. The monomeric status of the non-kinase receptor TβRⅢ is unchanged in the presence of TGF-β1. With the increase of receptor expression, both TβRI and TβRIII can be assembled into dimers on cell surfaces.

Mechanistic Insights into the Photophysics of Ortho-hydroxyl GFP Core Chromophores

Herein we have employed the MS-CASPT2//CASSCF method to study the S1 excited-state intramolecular proton transfers （ESIPTs） of recently synthesized ortho-hydroxyl GFP core chromophores, i.e. OHIM, CHBDI, and MHBID, and their excited-state relaxation pathways. We have found that in OHIM and CHBDI, the ESIPT process is associated with small barriers of 3.4 and 4.2 kcal/mol; while, in MHBDI, it becomes essentially barrierless. Moreover, we have found two main S1 excited-state radiationless channels. In the first one, the enol S1 species decays to the So state via the enol S1/S0 conical intersection after overcoming considerable barriers of 7.0 and 7.7 kcal/mol in OHIM and CHBDI （however, in MHBDI, it is nearly barrierless）. In the second one, the keto S] species is first generated through the ESIPT event; then, it is de-excited into the So state in the vicinity of the keto S1/S0 conical intersection. These energetically allowed excited-state decay channels rationalize ex- perimentally observed ultralow fluorescence quantum yields. The insights gained from the present work may help to guide the design of new ortho-hydroxyl GFP core chromophores with improved fluorescence emission and brightness.

White light emission from Dy^(3+)-doped LiLuF_4 single crystal grown by Bridgman method

Lithium lutetium fluoride(LiLuF4) single crystals doped with different Dy3+ ion concentrations were grown by Bridgman method. The Judd-Ofelt(J-O) strength parameters(Ω2, Ω4, Ω6) of Dy3+ in LiLuF4 crystal are calculated according to the measured absorption spectra and the J-O theory, by which the asymmetry of the Dy3+:LiLuF4 single crystal and the possibility of attaining stimulated emission from 4F9/2 level are analyzed. The capability of the Dy3+:LiLuF4 crystal in generating white light by simultaneous blue and yellow emissions under excitation with ultraviolet light is produced. The effects of excitation wavelength and doping concentration on chromaticity coordinates and photoluminescence intensity are also investigated. Favorable CIE coordinates, x=0.319 3 and y=0.349 3, can be obtained for Dy3+ ion in 2.701% molar doping concentration under excitation of 350 nm.