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.     

干湿循环作用下泥质白云岩能量机制试验研究

为揭示红页岩破坏的力学特性和能量演化规律,通过电液伺服机对红页岩进行三轴压缩试验,研究不同干湿循环作用下红页岩试样峰值强度特征、力学特性和能量演化规律。结果表明：干湿循环次数对红页岩的抗压强度有显著的影响,并呈负相关关系;干湿循环作用会使岩样破坏阶段的脆性减弱,延性增强,降低其物理力学特性;对比干湿循环作用前后试样的变形特征曲线图,红页岩原试样的变形量大于干湿循环作用后的试样变形量,约为后者的1.7倍;红页岩破坏后,原试样的耗散能增长速率为干湿循环作用后试样的2.4倍,因为干湿循环作用会软化红页岩岩石内部结构,使其破坏时体积应变变化缓慢,从而导致耗散能相比于原试样增长较慢。

     

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.     

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。     

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。     

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.     

能量回收系统的热力学分析

石油化工装置使用的能量由能量转换和能量回收两部分构成。能量回收系统起着减少供入能，降低能耗的重要作用。经分析提出了换热设备和换热网络损失计算方法，分析了传热温差对能量回收的影响，指出减少传热温差是减少过程损、提高能量回收率的重要途径；讨论了能量回收系统能量回收的限度及存在的热力学和经济两个限制点，经济限制点是技术经济优化的结果，是合成换热网络遵照的依据；最后，讨论了分析和夹点技术在节能中的作用及其关系。