Crystal-field engineering of ultrabroadband mid-infrared emission in Co2+-doped nano-chalcogenide glass composites

Tunable and ultrabroadband mid-infrared (MIR) emissions in the range of 2.5–4.5 μm are firstly reported from Co²⁺-doped nano-chalcogenide (ChG) glass composites. The composites embedded with a variety of binary (ZnS, CdS, ZnSe) and ternary (ZnCdS, ZnSSe) ChG nanocrystals (NCs) can be readily obtained by a simple one-step thermal annealing method. They are highly transparent in the near- and mid-infrared wavelength region. Low-cost and commercially available Er³⁺-doped fiber lasers can be used as the excitation source. By crystal-field engineering of the embedded NCs through cation- or anion-substitution, the emission properties of Co²⁺ including its emission peak wavelength and bandwidth can be tailored in a broad spectral range. The phenomena can be accounted for by crystal-field theory. Such nano-ChG composites, perfectly filling the 3–4 μm spectral gap between the oscillations of Cr²⁺ and Fe²⁺ doped IIVI ChG crystals, may find important MIR photonic applications (e.g., gas sensing), or can be used directly as an efficient pump source for Fe²⁺: IIVI crystals which are suffering from lack of pump sources.     

天然气新型气液分离器性能试验研究

为了解决天然气含有饱和水汽和少量烃降低输气效率、堵塞管线和设备等问题,利用旋风子、稳流元件、叶栅式分离元件、折流板式分离元件组合成新型天然气分离器。利用相位多普勒粒子分析仪对新型天然气分离器进出口粒子粒径与液态水含量的进行对比测试,以研究新型分离器的分离效率。结果表明:新型分离器具有良好的气液分离作用;在流量为10～64 m~3/h时,分离器的分离效率成抛物线形式,在33 m~3/h时分离器的分离效率降到最低值95.16%,主要原因是流量在33 m~3/h时,试验气液混合不均匀,导致内部流态紊乱,以至于试验测得分离效率相对偏低;在流量为10 m~3/h时分离器分离效率最高,为99.29%;分离器对该进口条件的气体中雾状液粒有较高的分离作用,且可以明显降低分离器出口气体中液粒的平均粒径;从进口到气相出口压力逐渐降低,总压降为950 Pa;流动区域速度梯度大不利于气液相分离,流动掺混会导致分离效率降低。     

锂离子在三维骨架复合锂金属负极中的沉积规律

锂金属具有极高的理论比容量和极低的氧化还原电极电势，成为了新一代高比能二次电池最理想的负极材料。然而，锂金属负极其走向大规模应用仍存在诸多问题与挑战。三维骨架复合负极可以控制金属锂均匀形核，低电流密度下均匀沉积，有望推动锂金属负极的实用化。为了更高效地指导锂金属负极设计和优化，采用相场理论，对三维骨架锂金属负极中比表面积对金属锂沉积过程的作用机制进行了定量分析和探究，发现了比表面积调控金属锂沉积的两阶段作用机理，并提出了基于比表面积参数的三维骨架负极设计与优化方向，从而最大程度发挥三维骨架在调控稳定金属锂负极上的积极作用。     

环氧丙烷产业现状及发展趋势

简述了全球及我国环氧丙烷产业的生产及供需现状;对环氧丙烷在聚醚多元醇、丙二醇/碳酸二甲酯、丙二醇醚及其酯类等领域的应用进行了分析;并对环氧丙烷生产技术进行了比较,提出了发展建议。     

低能量密度炸药连续装药光面爆破技术研究

为了提高光面爆破成型质量，提出了一种低能量密度炸药连续装药光面爆破技术，利用LS DYNA进行数值模拟，对比2#岩石乳化炸药间隔装药和低能量密度炸药连续装药的应力场，然后将此技术用于长九（神山）灰岩矿四号隧洞控制爆破和露天边坡光面爆破。结果表明：2#岩石乳化炸药间隔装药模型中，装药段与非装药段测点应力峰值相差很大；而在低能量密度炸药连续装药模型中，沿炮孔轴向相同爆心距的测点应力峰值保持一致；使用低能量密度炸药进行连续装药，能够避免装药段的过度破坏和非装药段的欠挖，提高残孔率，且省去了导爆索捆绑时间，提高周边孔装药效率，节省了爆破成本。     

浅谈船用主机使用低硫燃油面临的挑战与应对措施

介绍了低硫燃油和传统的船用高硫燃油在化学成分和物理特性方面存在的诸多不同;指出:IMO2020限硫令对船舶运营带来了很大的挑战。基于两大主机制造商的相关文件和实际服务经验，归纳总结了船用主机使用低硫燃油运营时应注意的事项及应对措施，为船舶安全稳定运营提供参考。     

低比转速压气机轮毂轮缘型线多目标优化设计

对电动增压器用低比转速离心压气机轮毂轮缘进行优化设计。采用NUMECA/FINE Design 3D对压气机进行几何参数化,生成数据库样本,利用人工神经网络和遗传算法对轮毂轮缘型线进行优化,并进行流场分析。仿真结果表明,在设计转速为40000 r/min时,优化后设计点压比和效率分别提高6.59%和3.73%。     

XJM-KS型浮选机矿化器负压产生机理研究

浮选机矿化器是用于浮选矿浆预处理的重要设备，其性能的优劣直接影响到浮选机的工作效果。文章通过流体力学仿真软件FLUENT对XJM-KS型浮选机矿化器的内部流场进行数值仿真，重点研究了聚焦式喷嘴布置所带来的流场特征。模拟结果表明，高速的矿浆射流能够在混合室内产生-2.43×10Pa的负压区，从而吸入大量的空气，实现空气与矿浆的有效混合与预矿化，与传统的机械搅拌式矿浆预处理装置相比，该矿化器能够大幅度提高预矿化效果。     

小庄煤矿地应力场分布规律实测与模拟研究

地应力场主要由自重应力场和构造应力场组成,是影响井下采掘工程活动最重要和最根本的因素,掌握矿井的地应力场分布规律,对整体提高矿井的经济效益和社会效益具有重要的意义。本文在小庄煤矿区域采用套空应力解除法进行地应力场测量,并采用三维应力场反演验证测量结果,从而得出了小庄煤矿的应力分布规律,为矿井动力现象的预测预防奠定了基础。     

Magnetic field coupling microfluidic synthesis of Fe2Pt/C nanocatalysts for enhanced electrochemical catalytic oxidation of alcohol

The influence of magnetic field (MF) on electrochemical catalytic properties of carbon supported Fe₂Pt nanocatalysts is investigated. Nanocatalysts are produced through an external MF coupled microfluidic process. X-ray diffraction (XRD) measurements show that Fe₂Pt nanocrystals (NCs) with larger sizes are synthesized when an external MF of 1.4 T is applied. X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) characterizations confirm that more Pt²⁺ reduces to Pt⁰ and NCs grow larger under magnetic fields (MFs) than those without MFs. The increased coercivity indicates that more surface unpaired electrons are present and the surface spin configuration changes under MFs. NCs synthesized under MFs show better catalytic performance in alcohol electrochemical catalytic oxidation reactions compared to samples synthesized without MFs. The mass activities significantly increase by 1.10 and 1.24 times and the specific activity increases up to 1.11 and 1.26 times for methanol and ethanol oxidation, respectively, compared to those without MFs.