CW-pumped evanescent amplification based on side-polished fiber with heavily Er3+-doped glass overlay

A novel diffractive-pumping scheme is proposed to improve the evanescent amplification using blazed fiber grating for the first time. We also investigate the cw-pumped-evanescent amplification at 1.55 mu m wavelength with the relative optical gain pumped at 1480 nm of around 2 dB based on side-polished fiber with the effective interaction length as long as 16 mm and with a heavily Er3+-doped (N-Er(3+) > 1.19 x 10(21) ions/cm(3)), low refractive index (n(1550) < 1.47) glass overlay, which has no concentration quenching (tau(f) = 9.0 ms).

飞秒激光用多层介质膜脉宽压缩光栅的设计

以薄膜光学的干涉理论和衍射光学的傅里叶模式理论为基础，给出了0．8μm飞秒激光器用多层介质膜脉宽压缩光栅的理论设计；设计采用H3L（HL）^9H0．5L2．4H的多层介质膜为基底，当刻蚀后表面浮雕结构的占宽比为0．35，线密度为1480线／mm，槽深为0．2μm，顶层HfO2的剩余厚度为0．15μm时，对于Littrow角度（36．7°）和TE波模式入射的衍射光栅其-1级衍射效率达到95％以上．

Interactions between climatic variables controlling subalpine tree growth: implications for climatic history of the Sierra Nevada, California

EXTRACT (SEE PDF FOR FULL ABSTRACT): Tree-ring records from foxtail pine (Pinus balfouriana) and western juniper (Juniperus occidentalis) growing near tree line in the eastern Sierra Nevada, California, show strong correlations with summer temperature and winter precipitation. Response surfaces portraying tree growth as a function of summer temperature and winter precipitation indicate a strong interaction between these variables in controlling growth. ... Above average growth for both foxtail pine and western juniper from AD 1480 to 1570 can be interpreted as indicating an extended period of warm, moist conditions unequalled during the 20th century.

“克洛曲 (复方克痛宁 )研究”获云南省科学技术二等奖

由中国科学院昆明动物研究所熊郁良、王婉瑜研究员主持的该项研究工作 ,在国际上首次发明了一种高效、广谱 ,具有镇痛、戒毒双重作用的新型不成瘾药物———克洛曲。该药以蛇毒神经毒为主 ,辅以起效快的曲马多、布洛芬 ,组成一个全面作用于中枢、外周神经传导突触后Ａｃｈ及植物神经系统的新复方制剂 ,在药效学、药理学及正交试验方面证明均优于国内外现有镇痛药。它克服了神经毒 (克痛宁 )起效慢、曲马多仅作用于中枢镇痛和可能产生耐药性或会成瘾、布洛芬仅作用于植物神经解热镇痛的缺点 ,将三条作用途径组成“克洛曲” ,充分发挥了各药品的特点 ,形成起效快、镇痛时间长、高效、广谱、毒性低的新型镇痛药物 ;该药还具有戒毒作用 ,且不成瘾 ,对患者免疫功能及性功能恢复都有显著效果。该工作为毒素研究和应用开创了一条新途径 ,有关论文在国际会议多次报道并全文刊登 ,受到好评。克洛曲作为镇痛药物已经卫生部新药办公室及医药管理局批准并获生产批文 ,列入部颁试验标准。 2 0 0 0年已在全国上市 ,并在云南省及全国部分地区作为戒毒辅助用药推广应用。目前正在进一步补充完善材料 ,拟报批为戒毒特药。该工作1998年经中国科学院组织专家鉴定 。

Sensor graphs for guaranteed cooperative localization performance

A group of mobile robots can localize cooperatively, using relative position and absolute orientation measurements, fused through an extended Kalman filter (ekf). The topology of the graph of relative measurements is known to affect the steady-state value of the position error covariance matrix. Classes of sensor graphs are identified, for which tight bounds for the trace of the covariance matrix can be obtained based on the algebraic properties of the underlying relative measurement graph. The string and the star graph topologies are considered, and the explicit form of the eigenvalues of error covariance matrix is given. More general sensor graph topologies are considered as combinations of the string and star topologies, when additional edges are added. It is demonstrated how the addition of edges increases the trace of the steady-state value of the position error covariance matrix, and the theoretical predictions are verified through simulation analysis.

Cu~(2+)对一种绿球藻生长及生理特性的影响

研究了不同浓度的Cu2+(0.01,0.1,1,10,50,100,200mg/L)对绿球藻(Chlorococcumsp.)生长、形态结构及生理特性的影响.结果表明,Cu2+对绿球藻的显微结构、生长及生理状态的影响比较显著.与对照BG11培养的绿球藻比较,0.01～1mg/LCu2+浓度下培养的绿球藻,细胞壁无明显增厚,色素没有多大变化,但蛋白核由一个变为多个;而在高浓度(10～200mg/LCu2+)下,细胞壁明显增厚为多层,色素减少,蛋白核减少并回复到1个或消失.低浓度Cu2+(0.01,0.1mg

Design and optimization of planar mesa termination for diamond Schottky barrier diodes

In this paper, we present planar mesa termination structure with high k dielectric Al2O3 for high-voltage diamond Schottky barrier diode. Analysis, design, and optimization are carried out by simulations using finite element technology computer-aided design (TCAD) Sentaurus Device software. The performances of planar mesa termination structure are compared to those of conventional field plate termination structure. It is found that optimum geometry of planar mesa terminated diode requires shorter metal plate extension (1/3 of the field plate terminated diode). Consequently, planar mesa terminated diode can be designed with bigger Schottky contact to increase its current carrying capability. Breakdown performance of field plate termination structure is limited at 1480 V due to peak electric field at the corner of Schottky contact (no oxide breakdown occurs). In contrast, peak electric field in planar mesa termination structure only occurs in the field oxide such that its breakdown performance is highly dependent on the oxide material. Due to Al2O3 breakdown, planar mesa termination structure suffers premature breakdown at 1440 V. Considering no oxide breakdown occurs, planar mesa termination structure can realize higher breakdown voltage of 1751 V. Therefore, to fully realize the potential of planar mesa terminated diode, it is important to choose suitable high k dielectric material with sufficient breakdown electric field for the field oxide. © 2013 Elsevier B.V.

Enhanced Proton Conduction in Polymer Electrolyte Membranes as Synthesized by Polymerization of Protic Ionic Liquid-Based Microemulsions

Proton-conducting membranes were prepared by polymerization of microemulsions consisting of surfactant-stabilized protic ionic liquid (PIL) nanodomains dispersed in a polymerizable oil, a mixture of styrene and acrylonitrile. The obtained PIL-based polymer composite membranes are transparent and flexible even though the resulting vinyl polymers are immiscible with PIL cores. This type of composite membranes have quite a good thermal stability, chemical stability, tunability, and good mechanical properties. Under nonhumidifying conditions, PIL-based membranes show a conductivity up to the order of 1 x 10(-1) S/cm at 160 degrees C, due to the well-connected PIL nanochannels preserved in the membrane. This type of polymer conducting membranes have potential application in high-temperature polymer electrolyte membrane fuel cells.

Broad-band semiconductor optical amplifiers

Broad-band semiconductor optical amplifiers (SOAs) with different thicknesses and thin bulk tensile-strained active layers were fabricated and studied. Amplified spontaneous emission (ASE) spectra and gain spectra of SOAs were measured and analyzed at different CW biases. A maximal 3 dB ASE bandwidth of 136 nm ranging from 1480 to 1616 nm, and a 3 dB optical amplifier gain bandwidth of about 90 nm ranging from 1510 to 1600 nm, were obtained for the very thin bulk active SOA. Other SOAs characteristics such as saturation output power and polarization sensitivity were measured and compared. (c) 2006 Elsevier B.V. All rights reserved.

Delay of the excited state lasing of 1310 nm InAs/GaAs quantum dot lasers by facet coating

In this letter, we present a facet coating design to delay the excited state (ES) lasing for 1310 nm InAs/GaAs quantum dot lasers. The key point of our design is to ensure that the mirror loss of ES is larger than that of the ground state by decreasing the reflectivity of the ES. In the facet coating design, the central wavelength is at 1480 nm, and the high- and low-index materials are Ta2O5 and SiO2, respectively. Compared with the traditional Si/SiO2 facet coating with a central wavelength of 1310 nm, we have found that with the optimal design the turning temperature of the ES lasing has been delayed from 90 to 100 degrees C for the laser diodes with cavity length of 1.2 mm. Furthermore, the characteristic temperature (T-0) of the laser diodes is also improved.