Seasonal variability of cloud optical depth over northwestern China derived from CERES/MODIS satellite measurements

The seasonal variability of cloud optical depth over northwestern China derived from Clouds and the Earth＇s Radiant Energy System （CERES） Single Scanner Footprint （SSF） Aqua Moderate Resolution Imaging Spectroradiometer （MODIS） Edition IB data from July 2002 to June 2004 is presented. The regions of interest are those with Asia monsoon influence, the Tianshan and Qilian Mountains, and the Taklimakan Desert. The results show that the instantaneous measurements presented here are much higher than the previous results derived from International Satellite Cloud Climatology Project （ISCCP） D2 monthly mean data. Generally the measurements of cloud optical depth are the highest in summer and the lowest in winter, however, Taklimakan Desert has the lowest measurements in autumn. The regional variation is quite significant over northwestern China.     

High-temperature sustainability of strong fiber Bragg gratings written into Sb-Ge-codoped photosensitive fiber: decay mechanisms involved during annealing

An antimony--germanium- (Sb--Ge-) codoped fiber specially designed for the fabrication of fiber Bragg gratings (FBGs) with high temperature sustainability has been developed. The photosensitivity and the high-temperature sustainability of FBGs that have been written into this fiber were tested. The results obtained showed that the FBG written into this fiber has a very high temperature sustainability of 900 degrees C. A decay mechanism that involves cation hopping is presented to explain the observed high temperature sustainability of the grating written into this fiber.     

从室温到1800℃全程测温的蓝宝石单晶光纤温度传感器

表述了从室温到１８００℃测温范围的全程测温的蓝宝石单晶光纤温度传感器。该光纤传感器综合了光纤辐射测温技术和光纤荧光测温技术的特点,利用特殊生长的端部Ｃｒ＾３＋离子掺杂的蓝宝石单 光纤,使两者有机地结合实现用单一光纤传感头达到大范围的温度测量,介绍了端部掺杂的蓝宝石单晶光纤的生长方法,分析了它的荧光温度特性、光纤传感头上荧光信号与热辐射信号的相互干扰以及光纤温度传感器的系统结构和工作原理,给出了实验     

Efficient parametric conversion from 1.06 to 3.8 μm by an aperiodically poled cascaded lithium niobate

We experimentally demonstrated an efficient optical parametric oscillator (OPO) with high parametric conversion from 1.0645 to 3.8?μm. An aperiodically poled magnesium oxide doped lithium niobate wafer was designed and fabricated as the nonlinear crystal of the OPO. A linearly polarized acousto-optic Q-switched Nd:YVO4 laser was used as the pump source. High pump-to-idler conversion efficiency of 18.5% was achieved with a slope efficiency of up to 21.5%. When compared with a periodically poled channel fabricated on the same wafer, under the condition of output coupler optimized for the periodically poled lithium niobate based OPO, an improvement of slope efficiency by 28.3% from 15.2% to 19.5% and total efficiency by 12.5% from 13.6% to 15.3% under the highest pump power of 11?W was realized for the pump-to-idler conversion.     

Widely tunable high power OPO based on a periodically poled MgO doped lithium niobate crystal

An optical parametric oscillator (OPO) based on a highly MgO doped periodically poled lithium niobate (PPMgLN) crystal was experimentally demonstrated and the result is presented in this report. The PPMgLN wafer was fabricated from a MgO doped (with 6 mol% doping concentration) lithium niobate crystal by means of high voltage pulse trigged domain reversal technique and has 20 domain reversal periods from 27.8 to with a step of between the neighbor periods. An acousto-optic (AO) Q-switched Nd³⁺:YVO₄ laser was used as the pumping laser. A maximum laser output power of 4.8 W has been achieved for the OPO when the pumping power is 10.8 W and it corresponds to an optic-optic conversion efficiency of 44%. By shifting the PPMgLN wafer, the periods of the domain structure on the PPMgLN wafer can be changed, thus enabling a wide spectral tuning range of the laser output from 1.42 to (for the signal light) and from 2.76 to (for the idler light).     

Widely tunable compact erbium-doped fiber ring laser for fiber-optic sensing applications

A compact erbium-doped ring-shaped fiber laser suitable for fiber-optic sensing applications has been developed. The fiber laser utilized a tunable fiber Fabry–Perot filter as the tuning element and had a moderate milli-Watt level power output over almost the whole tuning range from 1530 to 1595 nm with a power fluctuation of 0.15 dB. High repetition rate scanning of laser operation over the whole tuning range was achieved at rates of up to 200 Hz. Moreover, the performance of the ring-shaped fiber laser configured with a high-concentration erbium-doped fiber was investigated for its larger wavelength tunability of over 100 nm. Output power characteristics of this ring-shaped fiber laser were also investigated when it worked in a scanning mode. A distorted power wavelength dependence, as well as some pulsing phenomenon were observed in scanning mode.     

Gram-Scale Synthesis of Chain-Deuterated Sphingosine and Its Derivatization to Produce Ceramide,Sphinganine and Sphingosine-1-phosphate

Sphingosine plays crucial roles in various cellular functions. Deuterated molecules are widely used as the important tools to explore the structure, property, and function of biochemical materials. We here report a gram-scale synthesis of sphingosines with different deuterated chains. The synthesis started from different protiated fatty acids, which underwent hydrothermal platinum-catalyzed hydrogen/deuterium (H/D) exchange to produce the deuterated chains with different length. The Horner–Wadsworth–Emmons (HWE) coupling of a chiral amino acid derivative with the deuterated chains generated the unsaturated ketone precursors. The following stereoselective reduction via cyclic Felkin–Anh transition led to the desired anti-amino alcohol geometry. This efficient protocol enabled the gram-scale synthesis of the chain-deuterated sphingosines. The subsequent synthesis of the chain-deuterated derivatives, i. e. ceramide, sphinganine and sphingosine-1-phosphate, is also described. Their deuterium content was simultaneously characterized by ¹H NMR and high-resolution mass spectrum (HRMS).     

Transport of black carbon aerosols from non-local sources:A case study in Shanghai

Black carbon（BC） aerosol mass carried by winds of varying directions from non-local sources was estimated based on hourly measured data of BC mass concentration(C_BC) and meteorological parameters from January 2008 to December 2012 in Shanghai,and the relationship between annual average C_BC and wind speed was analyzed.The results show that the annual average C_BC decreased with wind speed for speeds exceeding 0.3 m/s.The relationship between the two was determined by a linear fit with correlation coefficient 0.88.Assuming BC aerosol mass of non-local sources transported by a southeast wind was zero,annual average BC concentrations（μg/m³） carried by winds of variable direction were 1.99（southwest）,1.95（west）,1.15（northwest）,0.54（south）,0.39（north）,0.01（northeast）,and 0.01（east）.BC aerosol mass of non-local sources transported by wind to Shanghai was about 6404.051 per year,among which the total contribution of southwest,west,and northwest winds was nearly 84%.The aerosol mass transported to Shanghai in winter accounted for 35%that of the entire year,and was greater than that of the other seasons.     

母岩高铀离子型稀土矿采区的放射性污染风险浅析

铀与稀土元素同属大离子亲石元素,尤其与钇组稀土关系更密切,因此南岭高铀花岗岩往往同时是铀和离子型重稀土矿床的成矿母岩。国内外研究资料表明,高铀花岗岩中的铀主要以原生铀的形式存在于晶质铀矿中,在强烈风化过程中大部分发生活化转移,而采矿活动对此有显著促进作用;国外众多含铀湿地的发现及其研究资料表明,山区湿地是铀的"高效过滤器"和"沉淀池",花岗岩风化转移到水体中的微量铀经长期累积,可在湿地富有机质土壤和沉积物中富集至(3000~4000)×10^-6,而采矿和农垦活动可将湿地经几千年累积富集起来的铀释放到居民的生活环境中,因而被视为是一种环境风险。因此建议加强母岩高铀离子型稀土矿区的湿地放射性调查和环境保护,以保障湿地对重金属的天然过滤功能,避免湿地束缚铀的释放,这对保护矿区水质和生态环境都具有重要意义。     

A quantitative measurement of binocular fusion for achromatic and chromatic colors

Optical Review - The stereo image consisting of an achromatic image and a chromatic image (mixed stereo pair) can be fused as a three-dimensional (3D) color scene by human observers. It is said...