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41.
Ying Wang Xingtao Dai Hongxin You Mengchun Gao 《International Journal of Hydrogen Energy》2018,43(41):19189-19195
A hydrogen supply system of 70 MPa hydrogen storage cylinder on vehicles is designed, in which a compressor is proposed to use the new type of ion compressor. The system is simulated statically by Aspen Plus. Meanwhile, during the process of hydrogen charged from the third-stage high-pressure hydrogen storage tank to the hydrogen storage cylinder on vehicles, the dynamic variety of the third-stage high-pressure hydrogen storage tank is simulated dynamically by Aspen HYSYS Through the simulation, obtaining the results that there are difference between theoretical calculation and simulation for the volume of third-stage high-pressure hydrogen storage tank and the average volume flow of hydrogen in a third-stage high-pressure hydrogen storage tank varies with its pressure and volume. By comparing the results of Aspen Plus simulation and Aspen HYSYS simulation, there are some differences. The designed system can be applied to hydrogen stations and any operating conditions involving the supply hydrogen. 相似文献
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从图像降质模型出发,研究运用最大后验概率(MAP)估计法实现图像超分辨率重建。简单介绍了MAP方法的发展现状,并分析了该算法中存在的缺陷,即目标函数的吉布斯(Gibbs)项对于重建图像的噪声抑制力不均衡。针对该缺陷采用原始低分辨率图像插值后图像的梯度场对MAP目标函数的Gibbs项系数进行修正,使该系数对各像素根据相应梯度值自适应的调整,在一定程度上均衡了目标函数对于不同梯度值区域的约束力。采用共轭梯度法对改进前后MAP算法分别求解并进行了仿真。结果显示相比传统MAP算法,改进的MAP算法得到的超分辨率图像,既很好地恢复了细节,又很好地抑制了重建过程中引入的噪声,总体像质有了明显提高,同时在迭代求解过程中也表现出很好的收敛性与稳定性。 相似文献
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文章用溶剂提取法从柑橘皮中提取抑菌活性成分.用滤纸片法和最低抑菌浓度法(MIC)判断提取物对大肠杆菌的抑菌效果,确定最佳提取条件.结果表明:乙醇浓度90%、提取温度50℃、提取时间4h时的提取物对供试菌的抑菌活性显著.短时间(10 min)热处理(100℃)对提取物的抑菌效果无影响. 相似文献
48.
利用XRD、SEM、NH3-PTD和吡啶吸附红外光谱等手段对ZSM-35和SAPO-11分子筛的结构和酸性质进行表征和对比,考察两种分子筛对正丁烯异构化制备异丁烯反应的催化性能。结果表明,对于硅铝型ZSM-35分子筛,由于存在较强的B酸中心,在异构化反应过程中,丁烯二聚及裂解等副反应发生多,异丁烯选择性低。而SAPO-11分子筛主要以中等偏弱的B酸中心为主,加上一维十元环孔道结构,在异构化反应中更有利于异丁烯的生成,表现出更高的异丁烯选择性及收率。 相似文献
49.
The application of in situ Raman, IR, and UV-Vis DRS spectroscopies during steady-state methanol oxidation has demonstrated
that the molecular structures of surface vanadium oxide species supported on metal oxides are very sensitive to the coordination
and H-bonding effects of adsorbed methoxy surface species. Specifically, a decrease in the intensity of spectral bands associated
with the fully oxidized surface (V5+) vanadia active phase occurred in all three studied spectroscopies during methanol oxidation. The terminal V = O (∼1030 cm−1) and bridging V–O–V (∼900–940 cm−1) vibrational bands also shifted toward lower frequency, while the in situ UV-Vis DRS spectra exhibited shifts in the surface
V5+ LMCT band (>25,000 cm−1) to higher edge energies. The magnitude of these distortions correlates with the concentration of adsorbed methoxy intermediates
and is most severe at lower temperatures and higher methanol partial pressures, where the surface methoxy concentrations are
greatest. Conversely, spectral changes caused by actual reductions in surface vanadia (V5+) species to reduced phases (V3+/V4+) would have been more severe at higher temperatures. Moreover, the catalyst (vanadia/silica) exhibiting the greatest shift
in UV-Vis DRS edge energy did not exhibit any bands from reduced V3+/V4+ phases in the d–d transition region (10,000–30,000 cm−1), even though d–d transitions were detected in vanadia/alumina and vanadia/zirconia catalysts. Therefore, V5+ spectral signals are generally not representative of the percent vanadia reduction during the methanol oxidation redox cycle,
although estimates made from the high temperature, low methoxy surface coverage IR spectra suggest that the catalyst surfaces
remain mostly oxidized during steady-state methanol oxidation (15–25% vanadia reduction). Finally, adsorbed surface methoxy
intermediate species were easily detected with in situ IR spectroscopy during methanol oxidation in the C–H stretching region
(2800–3000 cm−1) for all studied catalysts, the vibrations occurring at different frequencies depending on the specific metal oxide upon
which they chemisorb. However, methoxy bands were only found in a few cases using in situ Raman spectroscopy due to the sensitivity
of the Raman scattering cross-sections to the specific substrate onto which the surface methoxy species are adsorbed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
50.
采用高温氢气对不同活性炭进行处理,并分别采用比表面分析仪(BET)、红外光谱(IR)、氩气-程序升温脱附实验(Ar-TPD)和热重分析(TGA)对高温氢气处理前后的活性炭进行表征.结果表明,高温氢气处理对活性炭的孔结构和比表面影响较小,高温氢气处理后活性炭表面含氧官能团含量降低.以高温氢气处理后的活性炭为载体制备钯炭催化剂,催化剂上的钯的分散度降低,在粗对苯二甲酸精制反应中的初活性下降. 相似文献