Er3+/Yb3+/Tm3+/Pr3+共掺碲酸盐玻璃超宽带近红外发光性能研究

采用熔融淬火技术制备了0.2 mol% Er₂O₃、1 mo l% Yb₂O₃、0.1 mol% Tm₂O₃和x mol% Pr₆O₁₁( x=0.25、 0.3、0.35和0.4)掺杂的65TeO₂-15ZnO-10Na₂O-10WO₃系碲酸盐玻璃,通过X 射线衍射(X-ray diffraction,XRD)、差热扫描曲线(differential scanning calorimetry,DSC)对玻璃样 品的抗析晶性和热稳定性 进行了表征。结果表明,玻璃样品具备良好的抗析晶性,析晶温度和转变温度差值为140 ℃,具有较好 的热稳定性。吸收光谱结果显示,Er³⁺/Yb³⁺/Tm³⁺/Pr³⁺共掺碲 酸盐玻璃在980 nm处有较强的吸收峰,故可 以采用980 nm泵浦源对该玻璃样品进行激发。在1 200—2 000 nm近 红外波段范围,玻璃样品存在峰值中 心为1.35 μm、1.53 μm和1.8 μm 3个波段发射峰,且3个发射峰的荧光半高宽(full width at half maxima, FWHM)均大于100 nm,其覆盖了光信号传输的E、S、C和C+L 4个波段,大幅度地提高了掺铒 光纤放大器(erbium doped fiber amplifier,EDFA)的放大带宽。     

Enhancement of optical emission generated from femtosecond double-pulse laser-induced glass plasma at different sample temperatures in air

In double-pulse laser-induced breakdown spectroscopy(DP-LIBS), the collinear femtosecond double-pulse laser configuration is experimentally investigated with different initial sample temperatures using a Ti:sapphire laser. The glass sample is ablated to produce the plasma spectroscopy. During the experiment, the detected spectral lines include two Na(I) lines(589.0 nm and 589.6 nm) and one Ca(I) line at the wavelength of 585.7 nm. The emission lines are measured at room temperature(22 ℃) and three higher initial sample temperatures(T_s?=?100 ℃, 200 ℃, and 250 ℃). The inter-pulse delay time ranges from-250 ps to 250 ps.The inter-pulse delay time and the sample temperature strongly influence the spectral intensity,and the spectral intensity can be significantly enhanced by increasing the sample temperature and selecting the optimized inter-pulse time. For the same inter-pulse time of 0 ps(single-pulse LIBS), the enhancement ratio is approximately 2.5 at T_s?=?200 ℃ compared with that obtained at T_s?=?22 ℃. For the same inter-pulse time of 150 ps, the enhancement ratio can be up to 4 at T_s?=?200 ℃ compared with that obtained at T_s?=?22 ℃. The combined enhancement effects of the different initial sample temperatures and the double-pulse configuration in femtosecond LIBS are much stronger than that of the different initial sample temperatures or the double-pulse configuration only.     

地质矿产勘查风险成因及防范措施

矿物地质勘查过程不光滑。它可能出现在市场价格预测失败,财产损失和自然因素或人为因素造成的人为因素的勘探和预测过程中,以及矿床地质条件的变化。以及所产生的预期返回,无法完成经济风险。     

Effect of distances between lens and sample surface on laser-induced breakdown spectroscopy with spatial confinement

Spatial confinement can significantly enhance the spectral intensity of laser-induced plasma in air.It is attributed to the compression of plasma plume by the reflected shockwave.In addition,optical emission spectroscopy of laser-induced plasma can also be affected by the distance between lens and sample surface.In order to obtain the optimized spectral intensity,the distance must be considered.In this work,spatially confined laser-induced silicon plasma by using a Nd:YAG nanosecond laser at different distances between lens and sample surface was investigated.The laser energies were 12 mJ,16 mJ,20 mJ,and 24 mJ.All experiments were carried out in an atmospheric environment.The results indicated that the intensity of Si (I) 390.55 nm line firstly rose and then dropped with the increase of lens-to-sample distance.Moreover,the spectral peak intensity with spatial confinement was higher than that without spatial confinement.The enhancement ratio was approximately 2 when laser energy was 24 mJ.     

高应力红页岩巷道失稳机理与控制技术研究

为解决高应力红页岩巷道的维护难题,以平安磷矿二矿为工程背景,采用理论分析、数值模拟、室内测试及工业性试验等方法,研究了红页岩的微观结构特征及巷道失稳机理。研究表明:红页岩内部孔隙孔径主要集中在0~50nm与10~200μm的范围内。自然状态下孔径在10~200μm的微孔隙占总孔隙体积的37.45%,吸水后占比增加至45.82%,吸水后引发的岩石强度弱化是红页岩巷道失稳破坏的重要原因。提出了高强锚注+格栅拱架+小孔径锚索的高应力红页岩巷道支护对策,该支护结构能够适应红页岩巷道初期的变形要求,有效限制巷道出现过大的变形,并充分调动深部围岩的承载能力。现场监测表明红页岩巷道两帮最大变形量在100mm以内,顶板下沉量控制在40mm以内,锚索受力在100～120kN并趋于稳定,表明新方案控制效果良好。     

简单可靠的水位控制电路

本装置的特点:1电路结构简单;2高可靠性;3没有电极腐蚀污染水源以及不安全(水箱内设备带220V交流电)等各种常见电路的弊端。电路工作原理:电路如图1所示。为了便于阐述,假定浮子的位置在初始状态时,位于高、低位干     

炼厂散热的实用计算和经济分析

为适应炼厂对节能的测算、分析以及减少散热损失的需要,本文提出:(1)快速、准确地计算表面散热损失的算图和小型计算机程序;(2)确定(火用)-经济分析的管线经济保温厚度的方法和计算机程序;(3)裸露金属表面散热状况及保温措施的技术效果;(4)进行环境温度、装置负荷率、装置规模对散热单耗影响的定量分析。     

广州新电视塔超高异形核心筒施工技术

广州新电视塔核心筒结构具有超高、异形(椭圆形)、空间狭小、层高大、内隔结构复杂等特点,采用内置劲性柱,部分采用C80高强混凝土,使得结构模板设计和施工、设施设置、钢筋加工和绑扎、混凝土制备和泵送均面临很多挑战.通过采用弧形钢模板、整体提升钢平台;优化混凝土配合比设计后,采用两泵两布、一泵到顶等工艺和技术;对混凝土、钢筋等原材料严格控制等措施,有效地解决了上述问题.     

流体输送的经济管径和经济保温厚度

以流体输送的年操作费用与管线投资的年折旧费用之和最小作为目标函数,关联出无保温的低温流体和保温的热流体求解经济管径的数学模型及相应的PC-1500计算机计算程序.