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51.
带有多层介质衬底FSS的损耗和带宽特性分析 总被引:11,自引:2,他引:11
本文简要介绍应用模匹配方法分析带有多层介质衬底的FSS频率响应技术,在此基础上研究带有多层介质衬底的平面Y形缝隙周期阵列对平面波的频率传输特性。重点讨论介质层厚度变化对FSS传输损耗及带宽的影响。 相似文献
52.
Ignacio Contardi Laura Cornaglia Ana M. Tarditi 《International Journal of Hydrogen Energy》2017,42(12):7986-7996
The effect of the support shape on the deposition of ZrO2 by the vacuum-assisted dip-coating method was studied. Disc-shaped and tubular porous stainless steel substrates were used to obtain ZrO2 coated supports for the synthesis of PdAu alloy composite membranes. The microstructure of the ZrO2 modified supports was evaluated by scanning electron microscopy and confocal laser microscopy. Besides, a qualitative assessment of the porosity and roughness of the porous substrates was performed by confocal laser microscopy. Dense and continuous palladium-alloy films were deposited on top of the modified tubes after thirteen ZrO2 deposition-calcination cycles. Cross-section EDS mapping and XRD diffraction analysis showed that a complete PdAu alloy formation was obtained even after annealing at 723 K in hydrogen stream during 5 days. 相似文献
53.
Fluidized bed technology has been successfully used in the formation of different types of coatings, e.g. aluminizing [Surf. Coat. Technol. 120 (1999) 151; Steel Res. 66 (1995) 318; J. Mater. Sci. 35 (2000) 5493], chromizing [Surf. Coat. Technol. 120 (1999) 151; Steel Res. 66 (1995) 318; J. Mater. Sci. 35 (2000) 5493], nitriding [Heat treatment in fluidized bed furnaces, 1993], carburizing [Heat treatment in fluidized bed furnaces, 1993], carbonitriding [Heat treatment in fluidized bed furnaces, 1993]. Recently, this technology has been used for the deposition of hard boride layers onto ferrous substrates [Mater. Lett. 51 (2001) 156; Fifth International Conference on Heat Treatment Materials, Budapest, Hungary, vol. 3, 1986]. In the present paper, we used fluidized bed technology to deposit boride coatings onto non-ferrous metals and alloys. The coatings were examined by means of optical microscopy, Vickers microhardness and X-ray diffraction, to determine thickness and morphology, phase formation and properties. The properties of dry wear and thermal cycling oxidation of the coatings were evaluated. The as-produced coatings were characterized by adequate thickness and improved wear and oxidation resistance. 相似文献
54.
The scratch resistance of coatings and the adhesion between coating and substrate are usually determined in model experiments performed with sharp diamond indenters. These common methods as described for example in EN 1071-3 often fail for the combination of hard coatings on soft substrates due to very small critical loads or no detectable failure modes at all. Hence in the industry a lot of highly subjective and provisional test methods are used. On the one hand, quantitative comparability is difficult with common methods since defects already occur at very small loads for ductile and relative soft substrate materials like plastics. On the other hand, wear of the indenter in contact with hard coatings like pure diamond coatings requires its cost-intensive replacement.In this article a macroscopic tribological–mechanical test method is suggested which uses balls of hardened steel as indenters. A wide scope can be applied for both soft and hard coatings and different substrate materials. By variation of the ball-diameter, the normal contact force and the sliding speed different levels of stress and wear can be induced to analyze the tribological and mechanical behavior between body and counterpart as well as the interface of coating and substrate. To determine scratch resistance close to reality as usual scratch conditions on consumer products are better represented by a small ball than a sharp diamond indenter. Another benefit of the presented test method is the cost saving acquisition of the balls for indentation in very high quality as they are standard parts in the ball bearing industry. For every test on very hard coatings a new ball can be used with the possibility to detect the wear both on the base object and the counterpart. The occurring failure modes of coating and substrate also can be compared with comparatively easy numerical models to verify the results. Additionally to the test concept, first results of different coatings will be presented in this paper and compared with the results of common scratch tests. 相似文献
55.
以厚皮甜瓜“优选早蜜”为材料,研究了牛粪和麦秸混合腐熟物与沙化土不同体积配比基质中有机肥养分转化及其与甜瓜生长发育的关系。结果表明:在甜瓜生长过程中有机肥养分转化百分率为氮素呈线性上升、磷素呈先下降后缓慢上升、钾素为先降低后急剧上升的变化规律,其中磷、钾元素随着基质中有机肥含量的增加而增加。基质中速效氮的变化规律为先增高后降低,速效磷、钾则一直呈下降趋势;总氮、磷、钾和有机质均呈下降趋势,但均随基质中有机肥含量的增高而增大。甜瓜植株高度、茎粗、根系活力和叶片叶绿素含量等在甜瓜生长发育前期均随着基质中有机肥含量的增高而降低,但在中后期则随着其含量的增加而增大。从满足甜瓜生长过程中营养需求的角度综合考虑,以混合腐熟物与沙化土体积1∶1配比最佳,其次为0.75∶1,0.5∶1和0.25∶1。 相似文献
56.
A procedure for producing arrays of self-aligned carbon nanotubes (CNTs) using standard chemical vapor deposition (CVD) is
reported. Using UV photolithography, silicon substrates are patterned with a thin layer of thermally evaporated iron as a
CNT catalyst. The CVD synthesis was carried out over a small temperature range (700°C–800°C) using acetylene and methane gasses,
producing aligned CNT towers. Scanning electron microscopy (SEM) analysis shows a relationship between CNT tower height and
synthesis time. Additionally, results show that impurity particles dramatically effect CNT tower growth. These results indicate
that aligned CNTs can be produced in a desired pattern with height control. 相似文献
57.
Wayne M. Cranton Sharron L. Wilson Demosthenes C. Koutsogeorgis Richard Hedgley Stephen Lipiec 《Thin solid films》2007,515(24):8534-8538
The feasibility of low-temperature fabrication of transparent electrode elements from thin films of antimony-doped tin oxide (SnO2:Sb, ATO) has been investigated via inkjet printing, rf magnetron sputtering and post-deposition excimer laser processing. Laser processing of thin films on both glass and plastic substrates was performed using a Lambda Physik 305i excimer laser, with fluences in the range 20-100 mJ cm− 2 reducing sheet resistance from as-deposited values by up to 3 orders of magnitude. This is consistent with TEM analysis of the films that shows a densification of the upper 200 nm of laser-processed regions. 相似文献
58.
IC封装载板的新型表面涂饰层——ENEPIG 总被引:1,自引:0,他引:1
文章介绍一种新型的化学镀镍化学镀钯与浸金表面涂饰层,克服了化学镀镍浸金涂层的缺点,更加适合于IC封装载板上应用。 相似文献
59.
Michael G. Kane Lawrence Goodman Arthur H. Firester Paul C. van der Wilt Alexander B. Limanov James S. Im 《Journal of the Society for Information Display》2007,15(7):471-478
Abstract— CMOS TFT circuits were fabricated on plastic using sequential laterally solidified silicon combined with a low‐temperature CMOS process. The unity‐gain frequencies of the best of NMOS TFTs are greater than 250 MHz, and the CMOS ring oscillators operate at 100 MHz. To the best of the authors' knowledge, these are the highest‐frequency circuits ever fabricated directly on plastic. This high‐performance CMOS‐on‐plastic process can be applied to the fabrication of AMLCD integrated drivers and AMOLED pixels on plastic substrates. 相似文献
60.
The quality of GaAs substrate material for manufacturing ion implanted devices is routinely determined by an ion implantation
test. The test involves measuring an electrical quantity, such as sheet resistance, after implanting Si into the substrate.
This work employs GaAs TCAD simulation to address the range of validity of the implantation test and the pitfalls associated
with it. The results show that the electrical measurements are capable of discerning typical variation in the carbon concentration
in the substrate. But, the surface or interface charge on GaAs, which may result from processing involved in wafer preparation,
is also important. Therefore, while the implantation test in most cases is adequate to control the quality of the substrate,
the test is susceptible to misinterpretation owing to the variations arising from the process involved in wafer preparation
for the test. 相似文献