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41.
《中国稀土学报(英文版)》2020,38(5):523-530
A multidisciplinary approach for the production and characterization of a series of high concentration Er~(3+)activated SrLaGa_3 O_7(abbreviated as Er:SLGO) crystal fibers is shown to have a great promise for implementation in mid-infrared laser applications.The current approach includes the design and formation of unique layered tetrahedral network structures with several kinds of rare earth(RE) ions including Er ions distributing statistically between layers,such as Er:SLGO,Er,Nd:SLGO,Er,Yb,Ho:SLGO,Er,Eu:SLGO and Er,Ho:SLGO.Five kinds of Er:SLGO crystal fibers were designed to grow via a micropulling down method.Spectroscopic analyses show that Er,Yb,Ho:SLGO and Nd,Er:SLGO crystal fibers were superiorly endowed with inhomogeneous broadening absorption and strong emission.The unique structural components design enables the generation of improved absorption and emission recombination,and the inhibition of self-termination as well.Generally,the use of structural components design may warrant high-efficiency emissions in RE-doped crystal fibers. 相似文献
42.
高温好氧堆肥技术虽然可有效处理有机固体废物,但常常会释放大量的氨气和造成氮素损失。本文以硫酸镁、磷酸二氢钾、硫酸镁+磷酸二氢钾(分别记为MgSO4、KP和KPM处理组)为原位固氮剂,污泥和木屑为原料,进行高温好氧堆肥试验,研究以上原位固氮剂对污泥堆肥过程中的氨气挥发和氮素损失的影响。结果表明,硫酸镁(MgSO4)对物料pH有显著的降低效应,添加硫酸镁使堆体高温期pH降低至8.17,低于硫酸镁+磷酸二氢钾(KPM)组(8.55)和对照(CK)组(8.90)。与CK相比,MgSO4和KPM的NH3累积释放量分别降低了34%和28%,反而KP组增加了35%。对比不同条件下XRD图谱可知,MgSO4的固氮效应并不是由于MgNH4PO4·6H2O的生成,而是由于其对pH的降低效应造成的。堆肥结束后,除了KP组,各处理条件下的种子发芽率值(germination index,GI)均不会对后续使用带来不利影响。 相似文献
43.
《能源学会志》2020,93(3):977-990
Waste tires and cooking oil pose a serious danger to human health and environment. Self-reacting pyrolysis system for waste tires is designed and constructed for converting waste tires into oil that could be used as a sustainable fuel. This study aims to analyze the thermal microstructure of conventional fuels like light diesel oil (LDO) and heavy diesel oil (HDO) as well as blended with waste cooking oil (WCO) and tires pyrolysis oil (TPO) using a co-axial burner via flame spectroscopy analysis. The first Blend 1 (B1) consists of 20% WCO + 80% LDO, the second one (B2) consist of 20% WCO+80%HDO and the last one (B3) was 20%TPO and 80% LDO by mass. This percentage was chosen carefully and according to previous combustion characteristics results. The experimental results showed that B1 will shrink C2 radicals by nearly 61% and 64.5% at Ф = 0.63 and 0.96 respectively. B2 will decrease C2 radicals by nearly 19% and 82% at Ф = 0.63 and 0.96 respectively. Finally, B3 will reduce C2 radical's intensity by nearly 39% and 58% at Ф = 0.63 and 0.96 respectively. TPO produced CH emission radicals lower than that of LDO by nearly 5.9%. LDO droplets absorbed more radiation energy needed for excitation than that of WCO due to droplet size and fuel physic-chemical properties. B2 fuel is recommended to replace LDO at Ф = 0.63 and 0.96. 相似文献
44.
45.
为实现钱家营矿掘进工作面煤与瓦斯突出实时预警,提出一种基于瓦斯涌出特征的预警方法。依据巷道高低浓度甲烷传感器实时监测数据,通过离散回归理论分析煤与瓦斯突出前的瓦斯涌出量,建立预警指标特征序列,确定掘进工作面煤与瓦斯突出预警指标危险临界值:方差0.018,波峰差0.41,波动斜率±0.027。在此基础上构建了非接触式煤与瓦斯突出可视化预警系统并在钱家营矿进行现场应用。结果表明,以瓦斯涌出特征值作为预警指标,能够准确监测到井下瓦斯异常现象,达到瓦斯数据实时解算和可视化预警的目的,为钱家营矿掘进工作面防突工作提供技术借鉴。 相似文献
46.
As concrete freezes and thaws cracks may develop. These cracks can provide a path for water and ionic species to penetrate the concrete. This may reduce the service-life of the concrete element. In this study, X-ray computed tomography (CT) was used as a non-destructive technique to characterize the microstructure of mortar samples that were exposed to different levels of freeze-thaw damage by varying degree of saturation in the samples (75, 90, 95, and 100% degrees of saturation). Acoustic emission (AE) experiments were performed during freezing and thawing to investigate sample cracking behavior. The volume of cracks present within the mortar samples after freezing and thawing were determined using X-ray CT and compared to passive acoustic emission data. The location/source of cracks was also determined using X-ray CT. The crack sources (i.e., void, aggregate, interfacial transition zone, or paste) were determined using X-ray CT and were related to AE activities during cracking. Crack volumes were found to increase with increased levels of saturation, and visual observations of cracking were found to correlate with AE signatures of various crack sources. 相似文献
47.
Jiale Feng Lupeng Yang Alexander S. Romanov Jirawit Ratanapreechachai Antti‐Pekka M. Reponen Saul T. E. Jones Mikko Linnolahti Timothy J. H. Hele Anna Khler Heinz Bssler Manfred Bochmann Dan Credgington 《Advanced functional materials》2020,30(9)
Carbene‐metal‐amides (CMAs) are a promising family of donor–bridge–acceptor molecular charge‐transfer (CT) emitters for organic light‐emitting diodes. A universal approach is demonstrated to tune the energy of their CT emission. A blueshift of up to 210 meV is achievable in solid state via dilution in a polar host matrix. The origin of this shift has two components: constraint of thermally‐activated triplet diffusion, and electrostatic interactions between guest and polar host. This allows the emission of mid‐green CMA archetypes to be tuned to sky blue without chemical modifications. Monte‐Carlo simulations based on a Marcus‐type transfer integral successfully reproduce the concentration‐ and temperature‐dependent triplet diffusion process, revealing a substantial shift in the ensemble density of states in polar hosts. In gold‐bridged CMAs, this shift does not lead to a significant change in luminescence lifetime, thermal activation energy, reorganization energy, or intersystem crossing rate. These discoveries offer new insight into coupling between the singlet and triplet manifolds in CMA materials, revealing a dominant interaction between states of CT character. The same approach is employed using materials which have been chemically modified to alter the energy of their CT state directly, shifting the emission of sky‐blue chromophores into the practical blue range. 相似文献
48.
Neil Gerard Quigley Dr. Stefano Tomassi Dr. Francesco Saverio di Leva Dr. Salvatore Di Maro Dr. Frauke Richter Dr. Katja Steiger Prof. Dr. Susanne Kossatz Prof. Dr. Luciana Marinelli Dr. Johannes Notni 《Chembiochem : a European journal of chemical biology》2020,21(19):2836-2843
αvβ6 Integrin is an epithelial transmembrane protein that recognizes latency-associated peptide (LAP) and primarily activates transforming growth factor beta (TGF-β). It is overexpressed in carcinomas (most notably, pancreatic) and other conditions associated with αvβ6 integrin-dependent TGF-β dysregulation, such as fibrosis. We have designed a trimeric Ga-68-labeled TRAP conjugate of the αvβ6-specific cyclic pentapeptide SDM17 (cyclo[RGD-Chg-E]-CONH2) to enhance αvβ6 integrin affinity as well as target-specific in-vivo uptake. Ga-68-TRAP(SDM17)3 showed a 28-fold higher αvβ6 affinity than the corresponding monomer Ga-68-NOTA-SDM17 (IC50 of 0.26 vs. 7.4 nM, respectively), a 13-fold higher IC50-based selectivity over the related integrin αvβ8 (factors of 662 vs. 49), and a threefold higher tumor uptake (2.1 vs. 0.66 %ID/g) in biodistribution experiments with H2009 tumor-bearing SCID mice. The remarkably high tumor/organ ratios (tumor-to-blood 11.2; -to-liver 8.7; -to-pancreas 29.7) enabled high-contrast tumor delineation in PET images. We conclude that Ga-68-TRAP(SDM17)3 holds promise for improved clinical PET diagnostics of carcinomas and fibrosis. 相似文献
49.
某F级燃气电厂运行中发现NOx数值存在较大波动,通过分析和排查,发现烟气分析仪存在老化现象,同时CEMS仪表间存在布置不合理情况,通过处理NOx数值波动得以有效改善,可为同类电厂烟气系统数据异常处理提供参考。 相似文献
50.
采用直流电化学刻蚀方法制备扫描隧道显微镜钨针尖,研究了电化学刻蚀过程中NaOH溶液浓度、钨丝浸入长度和刻蚀电压对针尖形貌的影响。通过扫描电子显微镜(SEM)测量针尖曲率半径和针尖纵横比值,以表征针尖的尺寸和形状;通过能谱仪(EDS)分析针尖表面成分,以表征表面清洁度;通过场发射显微镜(FEM)得到Fowler-Nordheim (F-N)曲线来检测针尖发射性能。实验结果表明,当溶液浓度为2 mol/L、钨丝浸入长度为4 mm、刻蚀电压为3 V时,可以得到曲率半径约为100 nm、纵横比值为13的针尖,且表面无钨的氧化层。FEM结果显示当对针尖施加500 V的负偏压时,针尖可以稳定发射50 nA量级的电流,且针尖性能具有良好的一致性。 相似文献