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991.
采用有限元软件ABAQUS,建立垂直护岸板桩数值分析模型,研究板桩的弹性模量、波浪的波高和波长对桩身水平位移的影响。研究结果表明:垂直护岸板桩向临水侧位移,随着桩的入土深度增加,桩身位移先增大后减小,在深度13 m以下位移较小。板桩的弹性模量对桩身水平位移的影响较小,在其它条件相同的情况下,随着板桩的弹性模量增大,桩身水平位移从桩顶到深度为13 m处逐渐减小,弹性模量对深度13 m以下的板桩水平位移影响较小。波浪的波高和波长对深度0 m到13 m范围内板桩的水平位移影响较大,对深度13 m以下的板桩水平位移影响较小。在其它条件相同的情况下,随着波高的增大,桩身最大位移点处的深度逐渐增大,桩身水平位移从桩顶到深度为13 m处逐渐减小。随着波长的增大,桩身水平位移从桩顶到深度为13 m处逐渐减小。 相似文献
992.
Michael N. Gardos 《Tribology Letters》1995,1(1):67-85
440C steel thrust ball bearing races lubricated with 1 m thick sputtered films of MoS2 were tested in the unidirectional and oscillatory modes against bare steel balls in moderate (10–4–10–5 Pa 10–6–10–7 Torr) vacuum and in 1 atmosphere of 99.999% pure ( 1 ppm water) N2 in the same unbaked environmental chamber. Over 90% of the residual gases in the chamber vacuum consisted of H2O vapor. The bearings operated in N2 showed substantially longer lives compared to the specimens tested in vacuum. Scanning electron microscope (SEM) tribometry was also performed on an MoS2 film powder-burnished onto a 440C flat. This flat was repeatedly oscillated against bare, hemispherical-tipped 440C pins on fresh wear tracks in the same type of N2 and column vacuum of ~10–3 Pa 10–5 Torr itself containing over 90% residual H2O. The SEM-generated results on the burnished film confirmed the same, atmosphere-dependent difference in wear life observed with the sputtered layers. Varying the moisture content of the burnished flat and its immediate environment by cryosorption predictably manipulated the coefficient of friction and wear life of MoS2. The various possible causes of this perplexing phenomenon are reviewed, and a plausible hypothesis is offered attributing the unexpected wear life reduction to the physico-chemical consequences of residual H2O hydrogen-bonding to the oxidized and/or hydrated edge and basal plane sites of MoS2 in moderate vacuum. The site-specific sorption of water is severely hindered in 1 atm N2 by the gas molecules disrupting the H-bonding mechanism. 相似文献
993.
为了制备ZnO/C复合材料并探讨其吸波性能,利用金属有机骨架MOF-5为前驱物,采用溶剂热法制备了ZnO/C复合材料.利用X射线衍射仪、扫描电子显微镜、傅里叶转换红外光谱分析仪与矢量网络分析仪对ZnO/C复合材料的物相组成、微观结构、形貌及性能进行了分析.结果表明,ZnO/C复合材料是由薄片状组织堆叠形成的完整立方体结构,且ZnO与C分布均匀.当复合材料涂层厚度为7 mm时,在17.18 GHz处的反射损耗可以达到最大幅值.ZnO/C复合材料在远红外区和超远红外区均具有良好的吸波性能. 相似文献
994.
A Type of 1 nm Molybdenum Carbide Confined within Carbon Nanomesh as Highly Efficient Bifunctional Electrocatalyst 下载免费PDF全文
Zhihua Cheng Qiang Fu Qing Han Yukun Xiao Yuan Liang Yang Zhao Liangti Qu 《Advanced functional materials》2018,28(18)
Highly efficient platinum‐alternative bifunctional catalysts by using abundant non‐noble metal species are of critical importance to the future sustainable energy reserves. Unfortunately, current electrocatalysts toward hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR) are far from satisfactory because of lacking reasonable design and assembly protocols. A type of 1‐nm molybdenum carbide nanoparticles confined in mesh‐like nitrogen‐doped carbon (Mo2C@NC nanomesh) with high specific surface area is reported here. In addition to the superior ORR performance comparable to platinum, the catalyst offers a high HER activity with small Tafel slope of 33.7 mV dec?1 and low overpotential of 36 mV to reach ?10 mA cm?2. Theoretical calculations indicate that the active sites of the catalyst are mainly located at Mo atoms adjacent to the N‐doped carbon layer, which contributes the high HER activity. These findings show the great potential of Mo2C species in wide electrocatalysis applications. 相似文献
995.
Controlled Growth of MoS2 Nanosheets on 2D N‐Doped Graphdiyne Nanolayers for Highly Associated Effects on Water Reduction 下载免费PDF全文
Huidi Yu Yurui Xue Lan Hui Chao Zhang Yingjie Zhao Zhibo Li Yuliang Li 《Advanced functional materials》2018,28(19)
The first utilization of nitrogen‐doped graphdiyne (NGDY) as an efficient catalytic promoter for hydrogen evolution reaction (HER) is reported. X‐ray powder diffraction and X‐ray photoelectron spectroscopy studies indicate the presence of strong interactions between NGDY and MoS2, which should effectively facilitate the charge transport behavior and improvement of the HER kinetics. The creative hybridization of MoS2 and NGDY endows such heterostructure with structural and compositional advantages for boosting the catalytic activity (low overpotential of 186 mV at 10 mA cm?2 and Tafel slope of 63 mV dec?1) and extraordinary stability (higher than all reported MoS2‐based materials and even better than that of commercial Pt and almost all benchmarked electrocatalysts). All of the results not only demonstrate that NGDY can be used as an effective catalytic promoter for hydrogen production, but also provide new strategy for fabricating efficient water‐splitting electrodes. 相似文献
996.
NIR Light‐Triggered Degradable MoTe2 Nanosheets for Combined Photothermal and Chemotherapy of Cancer 下载免费PDF全文
Ning Ma Ming‐Kang Zhang Xiao‐Shuang Wang Lu Zhang Jun Feng Xian‐Zheng Zhang 《Advanced functional materials》2018,28(31)
Telluride molybdenum (MoTe2) nanosheets with wide near‐infrared (NIR) absorbance are functionalized with polyethylene glycol‐cyclic arginine‐glycine‐aspartic acid tripeptide (PEG‐cRGD). After loading a chemotherapeutic drug (doxorubicin, DOX), MoTe2‐PEG‐cRGD/DOX is used for combined photothermal therapy and chemotherapy. With the high photothermal conversion efficiency, MoTe2‐PEG‐cRGD/DOX exhibits favorable cells killing ability under NIR irradiation. Owing to the cRGD‐mediated specific tumor targeting, MoTe2‐PEG‐cRGD/DOX shows efficient accumulation in tumors to induce a strong tumor ablation effect. MoTe2‐PEG‐cRGD nanosheets, which are relatively stable in the circulation, could be degraded under NIR ray. The in vitro and in vivo experimental results demonstrate that this theranostic nanoagent, which could accumulate in tumors to allow photothermal imaging and combined therapy, is readily degradable in normal organs to enable rapid excretion and avoid long‐term retention/toxicity, holding great potential to treat tumor effectively. 相似文献
997.
Functionalization of Graphene Oxide Films with Au and MoOx Nanoparticles as Efficient p‐Contact Electrodes for Inverted Planar Perovskite Solar Cells 下载免费PDF全文
Sumit S. Bhosale Efat Jokar Amir Fathi Cheng‐Min Tsai Chi‐Yung Wang Eric Wei‐Guang Diau 《Advanced functional materials》2018,28(37)
A graphene oxide (GO) film is functionalized with metal (Au) and metal‐oxide (MoOx) nanoparticles (NPs) as a hole‐extraction layer for high‐performance inverted planar‐heterojunction perovskite solar cells (PSCs). These NPs can increase the work function of GO, which is confirmed with X‐ray photoelectron spectra, Kelvin probe force microscopy, and ultraviolet photoelectron spectra measurements. The down‐shifts of work functions lead to a decreased level of potential energy and hence increased Voc of the PSC devices. Although the GO‐AuNP film shows rapid hole extraction and increased Voc, a Jsc improvement is not observed because of localization of the extracted holes inside the AuNP that leads to rapid charge recombination, which is confirmed with transient photoelectric measurements. The power conversion efficiency (PCE) of the GO‐AuNP device attains 14.6%, which is comparable with that of the GO‐based device (14.4%). In contrast, the rapid hole extraction from perovskite to the GO‐MoOx layer does not cause trapping of holes and delocalization of holes in the GO film accelerates rapid charge transfer to the indium tin oxide substrate; charge recombination in the perovskite/GO‐MoOx interface is hence significantly retarded. The GO‐MoOx device consequently shows significantly enhanced Voc and Jsc, for which its device performance attains PCE of 16.7% with great reproducibility and enduring stability. 相似文献
998.
Reyhan Sengur-Tasdemir Zeliha Guler-Gokce A. Sezai Sarac 《Polymer-Plastics Technology and Engineering》2018,57(2):59-69
UV spectroscopy and electrochemical impedance spectroscopy were used to investigate the properties and performances of ultrafiltration membranes fabricated with different polymers. Membrane performances were studied by means of permeability and bovine serum albumin filtration. UV spectroscopy results showed that bovine serum albumin rejection was lowest in polyvinylidene fluoride membranes, whereas it was highest in polysulfone membranes. Electrochemical impedance spectroscopy data revealed that after bovine serum albumin filtration, resistance of the membranes was increased though double layer capacitances were decreased. Performance data of UV spectroscopy and electrochemical impedance spectroscopy were in correlation with each other. This study demonstrated that electrochemical impedance spectroscopy can be successfully used in filtration membrane studies. 相似文献
999.
The effect of molybdenum disulphide additives on the tribological properties of high-speed powder steels produced by hot isostatic pressing has been investigated. The firction coefficients are determined at sliding velocities from 0.5 to 2.0 m/s and under loads from 1 to 15 Mpa, and the wear resistance of the experimental steel is determined. It is shown that the molybdenum disulphide additives reduce the friction coefficient and promote the wear resistance of the steel. 相似文献
1000.