伊犁盆地ZK0407井褐煤中铀及其他元素的地球化学研究

用数理统计的方法,对伊犁盆地洪海沟地区ZK0407井的中下侏罗统10、11、12号煤层中的铀等59种常量元素、微量元素的地球化学行为进行了探讨。结果表明,元素在灰分的分布和元素在内在水分以及固定碳中的分布呈互为相反数关系,而和元素在挥发分中的分布变化具有同步性。元素和挥发分呈正相关很大程度是因为元素的催化作用和矿物分解产生的一些挥发性组分所造成。ZK0407井在地史上一直位于砂岩层间氧化带的氧化-还原过渡地段,因而也是铀的富矿地段。其煤层为层间氧化带成矿的下翼。U等元素在褐煤中主要以物理吸附的方式存在于其孔隙之中或泥质组分中,有机质对其络合束缚作用,并非U在褐煤中的唯一富集方式。
     

Wildly Tunable,High-Efficiency MgO：PPLN Mid-IR Optical Parametric Oscillator Pumped by a Yb-Fiber Laser

We demonstrate a wildly tunable, high-eFficiency mid-infrared （mid-IR） output-coupled single resonant optical parametric oscillator （OC-SRO） pumped by a Yb-fiber laser. The compact mid-infrared source employs a 50- mm-long, multi-grating MgO-doped periodically poled lithium niobate （MgO-PPLN） crystal, providing as much as 1.73 W idler power at 3.012#m, and 1.27W signal power at 1645nm, corresponding to an overall conversion efficiency of 41.7% and a slope efficiency of 77.9%. In particular, the mid-infrared output power of 1.03 W and 0.67W are obtained at 3.7μm and 3.9μm, respectively, with an optical-to-optical conversion efficiency of 14.3% and 9.3%. Furthermore, the idler light is tunable from 3 μm to 3.9 μm by changing the periods from 31 to 28.5μm, with the output power 〉1 W over 78% of the tuning range. Our experimental results are pump power limited and further mid-IR power and conversion efficiency could be obtained with a suitable high-power pump source. The total OC-SRO output power rms at 2.6 W is about 0.6% during 2 h measurement.