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991.
The coked Mo-Co/γ-Al2O3 catalysts were Soxhlet extracted with the solvent of tetrahydrofuran. Experimental techniques like FT-IR, GC-MS, XPS, H2-TPR, BET, etc. were applied for the characterization of coke and catalysts to make a comparison of their physical properties. The results showed that the active components of the catalyst were slightly less after the reaction. The specific surface area and the pore volume had recovered to some degree. These results indicated that the main cause of deactivation of Mo-Co/γ-Al2O3 catalysts is carbon deposit. The principal components of the soluble carbon deposit on Mo-Co/γ-Al2O3 catalysts were alkyl aromatics with 1–4 rings and C19–C29 long-chain alkane compounds. 相似文献
992.
Jacob L. Jones James M. LeBeau Jason Nikkel Adedapo A. Oni J. Houston Dycus Clayton Cozzan Fang‐Yin Lin Aleksandr Chernatynskiy Juan C. Nino Susan B. Sinnott Sungwook Mhin Geoff L. Brennecka Jon Ihlefeld 《Advanced Materials Interfaces》2015,2(10)
Understanding interfaces between dissimilar materials is crucial to the development of modern technologies, for example, semiconductor–dielectric and thermoelectric–semiconductor interfaces in emerging electronic devices. However, the structural characterization of buried interfaces is challenging because many measurement techniques are surface sensitive by design. When interested in interface evolution during synthesis, the experimental challenges multiply and often necessitate in situ techniques. For solution‐derived lead zirconate titanate (PZT) ferroelectric thin films, the evolution of buried interfaces during synthesis (including dielectric–metal and metal–metal) is thought to dramatically influence the resultant dielectric and ferroelectric properties. In the present work, multiple experimental and computational methods are combined to characterize interface evolution during synthesis of ferroelectric PZT films on platinized Si wafers—including in situ X‐ray diffraction during thermal treatment, aberration‐corrected scanning transmission electron microscopy of samples quenched from various synthesis states, and calculations using density functional theory. Substantial interactions at buried interfaces in the PZT/Pt/Ti/SiO x /Si heterostructure are observed and discussed relative to their role(s) in the synthesis process. The results prove that perovskite PZT nucleates directly from the platinum (111)‐oriented bottom electrode and reveal the roles of Pb and O diffusion and intermetallic Pt3Pb and Pt3Ti phases. 相似文献
993.
994.
In this work, the dielectric properties of porous Si for its use as a local substrate material for the integration on the Si wafer of millimeter-wave devices were investigated in the frequency range 140 to 210 GHz. Broadband electrical characterization of coplanar waveguide transmission lines (CPW TLines), formed on the porous Si layer, was used in this respect. It was shown that the dielectric parameters of porous Si (dielectric permittivity and loss tangent) in the above frequency range have values similar to those obtained at lower frequencies (1 to 40 GHz). More specifically, for the samples used, the obtained values were approximately 3.12 ± 0.05 and 0.023 ± 0.005, respectively. Finally, a comparison was made between the performance of the CPW TLines on a 150-μm-thick porous Si layer and on three other radiofrequency (RF) substrates, namely, on trap-rich high-resistivity Si (trap-rich HR Si), on a standard complementary metal-oxide-semiconductor (CMOS) Si wafer (p-type, resistivity 1 to 10 Ω.cm) and on quartz.
PACS
84.40.-x; 77.22.Ch; 81.05.Rm 相似文献995.
996.
通过对瑞雷波法检测原理和方法的介绍,提出运用瑞雷波法对高速公路进行台背回填质量的无损检测,结合湖南某高速公路的工程实例,对比了注浆处治前后台背回填质量瑞雷波检测结果,并和钻芯取样检测结果进行比较,结果表明瑞雷波法测试台背回填质量较为可靠。 相似文献
997.
998.
999.
The effects of ZnO glass addition on the microwave dielectric properties of Ni0.5Ti0.5NbO4 (NTN) ceramics prepared by solid-state reaction method have been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). The pure NTN ceramics have εr of 60.6, Q × f value of 70,100 GHz, and τf value of 76.6 ppm °C−1 sintered at 1140 °C for 6 h. The results indicate that the addition of ZnO can effectively benefit the densification and further improve the dielectric constant. Moreover, the lower sintering temperature of NTN ceramics from 1140 to 930 °C is obtained by the addition of ZnO glass. However, an excess of ZnO suppresses the grain growth and decreases the Q × f value of NTN ceramics. The NTN ceramics with 2 wt% ZnO sintered at 930 °C for 6 h possess promising microwave dielectric properties: εr of 56.3, Q × f value of 67,000 GHz, and τf value of 78.6 ppm °C−1, which shows that the materials are suitable for low-temperature co-fired ceramics applications. 相似文献
1000.
Somnath Middya Animesh Layek Arka Dey Partha Pratim Ray 《材料科学技术学报》2014,30(8):770-775
In this paper,we have reported the synthesis of FeS2 of higher band gap energy(2.75 eV) by using capping reagent and its successive application in organic-inorganic based hybrid solar cells.Hydrothermal route was adopted for preparing iron pyrite(FeS2) nanoparticles with capping reagent PEG-400.The quality of synthesized FeS2 material was confirmed by X-ray diffraction,field emission scanning electron microscopy,transmission electron microscopy,Fourier transform infrared,thermogravimetric analyzer,and Raman study.The optical band gap energy and electro-chemical band gap energy of the synthesized FeS2 were investigated by UV-vis spectrophotometry and cyclic voltammetry.Finally band gap engineered FeS2 has been successfully used in conjunction with conjugated polymer MEHPPV for harvesting solar energy.The energy conversion efficiency was obtained as 0.064%with a fill-factor of 0.52. 相似文献