共查询到20条相似文献,搜索用时 31 毫秒
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K. Schulze J. Hausmann S. Heilmann B. Wielage 《Materialwissenschaft und Werkstofftechnik》2014,45(6):537-545
The adhesion and failure mechanism at well‐designed titanium‐PEEK interfaces within Ti‐CF/PEEK laminates are investigated by superposed mode I‐ and mode II‐loading before and after hydrothermal aging. The laser‐induced columnar structured oxide layer enhances the adhesion at the Titanium‐PEEK interface. PEEK‐Polymer that is locked mechanically in the capillary gaps of the columnar oxide structure are stretched and stiffed in the case of loading resulting in good adhesion. The adhesion at the oxide structure reduces by the influence of hydrothermal aging. Basically, the failure mechanism is not changed. Thus, the columnar oxide structure leads to enhanced humidity resistance of the adhesion between titanium and PEEK. The PEEK‐Polymer is also locked in the undercuts between the depressions and rims of the laser‐induced dot‐like surface structure resulting in adhesion. The adhesion at the dot‐like structured surface is nearly completely reduced by the influence of hydrothermal aging. The failure mechanism is changed from ductile failure within the PEEK‐Polymer to party disrupted rims and melt spatter. 相似文献
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Haitao Liu Yaqing Wang Kangli Cui Yaqiong Guo Xu Zhang Jianhua Qin 《Advanced materials (Deerfield Beach, Fla.)》2019,31(50)
Significant advances in materials, microscale technology, and stem cell biology have enabled the construction of 3D tissues and organs, which will ultimately lead to more effective diagnostics and therapy. Organoids and organs‐on‐a‐chip (OOC), evolved from developmental biology and bioengineering principles, have emerged as major technological breakthrough and distinct model systems to revolutionize biomedical research and drug discovery by recapitulating the key structural and functional complexity of human organs in vitro. There is growing interest in the development of functional biomaterials, especially hydrogels, for utilization in these promising systems to build more physiologically relevant 3D tissues with defined properties. The remarkable properties of defined hydrogels as proper extracellular matrix that can instruct cellular behaviors are presented. The recent trend where functional hydrogels are integrated into organoids and OOC systems for the construction of 3D tissue models is highlighted. Future opportunities and perspectives in the development of advanced hydrogels toward accelerating organoids and OOC research in biomedical applications are also discussed. 相似文献
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Hio‐Ieng Un Peng Cheng Ting Lei Chi‐Yuan Yang Jie‐Yu Wang Jian Pei 《Advanced materials (Deerfield Beach, Fla.)》2018,30(18)
Organic field‐effect transistors (OFETs) with impressively high hole mobilities over 10 cm2 V?1 s?1 and electron mobilities over 1 cm2 V?1 s?1 have been reported in the past few years. However, significant non‐ideal electrical characteristics, e.g., voltage‐dependent mobilities, have been widely observed in both small‐molecule and polymer systems. This issue makes the accurate evaluation of the electrical performance impossible and also limits the practical applications of OFETs. Here, a semiconductor‐unrelated, charge‐trapping‐induced non‐ideality in OFETs is reported, and a revised model for the non‐ideal transfer characteristics is provided. The trapping process can be directly observed using scanning Kelvin probe microscopy. It is found that such trapping‐induced non‐ideality exists in OFETs with different types of charge carriers (p‐type or n‐type), different types of dielectric materials (inorganic and organic) that contain different functional groups (? OH, ? NH2, ? COOH, etc.). As fas as it is known, this is the first report for the non‐ideal transport behaviors in OFETs caused by semiconductor‐independent charge trapping. This work reveals the significant role of dielectric charge trapping in the non‐ideal transistor characteristics and also provides guidelines for device engineering toward ideal OFETs. 相似文献
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Rotating‐Electric‐Field‐Induced Carbon‐Nanotube‐Based Nanomotor in Water: A Molecular Dynamics Study
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Md. Mushfiqur Rahman Mokter Mahmud Chowdhury Md. Kawsar Alam 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(19)
Using molecular dynamics simulations, it is shown that a carbon nanotube (CNT) suspended in water and subjected to a rotating electric field of proper magnitude and angular speed can be rotated with the aid of water dipole orientations. Based on this principle, a rotational nanomotor structure is designed and the system is simulated in water. Use of the fast responsiveness of electric‐field‐induced CNT orientation in water is employed and its operation at ultrahigh‐speed (over 1011 r.p.m.) is shown. To explain the basic mechanism, the behavior of the rotational actuation, originated from the water dipole orientation, is also analyzed . The proposed nanomotor is capable of rotating an attached load (such as CNT) at a precise angle as well as nanogear‐based complex structures. The findings suggest a potential way of using the electric‐field‐induced CNT rotation in polarizable fluids as a novel tool to operate nanodevices and systems. 相似文献
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Caofeng Pan Mengxiao Chen Ruomeng Yu Qing Yang Youfan Hu Yan Zhang Zhong Lin Wang 《Advanced materials (Deerfield Beach, Fla.)》2016,28(8):1535-1552
Wurtzite materials exhibit both semiconductor and piezoelectric properties under strains due to the non‐central symmetric crystal structures. The three‐way coupling of semiconductor properties, piezoelectric polarization and optical excitation in ZnO, GaN, CdS and other piezoelectric semiconductors leads to the emerging field of piezo‐phototronics. This effect can efficiently manipulate the emission intensity of light‐emitting diodes (LEDs) by utilizing the piezo‐polarization charges created at the junction upon straining to modulate the energy band diagrams and the optoelectronic processes, such as generation, separation, recombination and/or transport of charge carriers. Starting from fundamental physics principles, recent progress in piezo‐phototronic‐effect‐enhanced LEDs is reviewed; following their development from single‐nanowire pressure‐sensitive devices to high‐resolution array matrices for pressure‐distribution mapping applications. The piezo‐phototronic effect provides a promising method to enhance the light emission of LEDs based on piezoelectric semiconductors through applying static strains, and may find perspective applications in various optoelectronic devices and integrated systems. 相似文献
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Zeyu Jin Juan Lv Henglei Jia Weihong Liu Huanglong Li Zuhuang Chen Xi Lin Guoqiang Xie Xingjun Liu Shuhui Sun Hua‐Jun Qiu 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(47)
Ir‐based binary and ternary alloys are effective catalysts for the electrochemical oxygen evolution reaction (OER) in acidic solutions. Nevertheless, decreasing the Ir content to less than 50 at% while maintaining or even enhancing the overall electrocatalytic activity and durability remains a grand challenge. Herein, by dealloying predesigned Al‐based precursor alloys, it is possible to controllably incorporate Ir with another four metal elements into one single nanostructured phase with merely ≈20 at% Ir. The obtained nanoporous quinary alloys, i.e., nanoporous high‐entropy alloys (np‐HEAs) provide infinite possibilities for tuning alloy's electronic properties and maximizing catalytic activities owing to the endless element combinations. Particularly, a record‐high OER activity is found for a quinary AlNiCoIrMo np‐HEA. Forming HEAs also greatly enhances the structural and catalytic durability regardless of the alloy compositions. With the advantages of low Ir loading and high activity, these np‐HEA catalysts are very promising and suitable for activity tailoring/maximization. 相似文献
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Mohammad Taghinejad Hossein Taghinejad Zihao Xu Yawei Liu Sean P. Rodrigues Kyu‐Tae Lee Tianquan Lian Ali Adibi Wenshan Cai 《Advanced materials (Deerfield Beach, Fla.)》2018,30(9)
The optical Kerr nonlinearity of plasmonic metals provides enticing prospects for developing reconfigurable and ultracompact all‐optical modulators. In nanostructured metals, the coherent coupling of light energy to plasmon resonances creates a nonequilibrium electron distribution at an elevated electron temperature that gives rise to significant Kerr optical nonlinearities. Although enhanced nonlinear responses of metals facilitate the realization of efficient modulation devices, the intrinsically slow relaxation dynamics of the photoexcited carriers, primarily governed by electron–phonon interactions, impedes ultrafast all‐optical modulation. Here, femtosecond (≈190 fs) all‐optical modulation in plasmonic systems via the activation of relaxation pathways for hot electrons at the interface of metals and electron acceptor materials, following an on‐resonance excitation of subradiant lattice plasmon modes, is demonstrated. Both the relaxation kinetics and the optical nonlinearity can be actively tuned by leveraging the spectral response of the plasmonic design in the linear regime. The findings offer an opportunity to exploit hot‐electron‐induced nonlinearities for design of self‐contained, ultrafast, and low‐power all‐optical modulators based on plasmonic platforms. 相似文献
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H. Hildebrand 《Materialwissenschaft und Werkstofftechnik》2000,31(10):899-903
Semicoherent precipitates in a Fe‐Cr‐C alloy Precipitation processes in ferromagnetic materials can be recorded very well by measuring the sensitive coercive field strength. It should be tested, whether also semicoherent precipitates have a sufficient clear interaction with Bloch‐walls. For this purpose the mild‐magnetic alloy X1FeCr25 served. To carry out the evidence sensitively, a method based on differences between HCt (heat‐treated state at T = 600…︁700°C) – HC0 (quenched state from high temperature) = Δ HC was used. A quantitative record of the amount of precipitates (as particle size) is possible by a decomposition parameter Δ HC/Δ t. Plate‐like β′‐precipitates with planes {100}∥{100} in the α‐Fe solid solution have been proved by transmission electron microscopic investigations; this is the preparation state for the transition into the stable fcc phase M23C6. As a result, the quantitative electron microscopic proof of the β′‐phase can be supported by magnetic measurements, qualitatively and quantitatively. The estimated values of the activation energy for the process in the 1st maximum of precipitation in X1FeCr25 are higher than for the stable phases as the orthorhombic M3C or the cubic complex M6C in other steels and give a hint to the difficult processes related to nucleation as to the transition into M23C6. 相似文献
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Low‐Noise and Large‐Linear‐Dynamic‐Range Photodetectors Based on Hybrid‐Perovskite Thin‐Single‐Crystals
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Chunxiong Bao Zhaolai Chen Yanjun Fang Haotong Wei Yehao Deng Xun Xiao Lingliang Li Jinsong Huang 《Advanced materials (Deerfield Beach, Fla.)》2017,29(39)
Organic–inorganic halide perovskites are promising photodetector materials due to their strong absorption, large carrier mobility, and easily tunable bandgap. Up to now, perovskite photodetectors are mainly based on polycrystalline thin films, which have some undesired properties such as large defective grain boundaries hindering the further improvement of the detector performance. Here, perovskite thin‐single‐crystal (TSC) photodetectors are fabricated with a vertical p–i–n structure. Due to the absence of grain‐boundaries, the trap densities of TSCs are 10–100 folds lower than that of polycrystalline thin films. The photodetectors based on CH3NH3PbBr3 and CH3NH3PbI3 TSCs show low noise of 1–2 fA Hz?1/2, yielding a high specific detectivity of 1.5 × 1013 cm Hz1/2 W?1. The absence of grain boundaries reduces charge recombination and enables a linear response under strong light, superior to polycrystalline photodetectors. The CH3NH3PbBr3 photodetectors show a linear response to green light from 0.35 pW cm?2 to 2.1 W cm?2, corresponding to a linear dynamic range of 256 dB. 相似文献
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Arri Priimagi Marco Saccone Gabriella Cavallo Atsushi Shishido Tullio Pilati Pierangelo Metrangolo Giuseppe Resnati 《Advanced materials (Deerfield Beach, Fla.)》2012,24(44):OP345-OP352
It is demonstrated that halogen bonding can be used to construct low‐molecular‐weight supramolecular complexes with unique light‐responsive properties. In particular, halogen bonding drives the formation of a photoresponsive liquid‐crystalline complex between a non‐mesogenic halogen bond‐donor molecule incorporating an azo group, and a non‐mesogenic alkoxystilbazole moiety, acting as a halogen bond‐acceptor. Upon irradiation with polarized light, the complex exhibits a high degree of photoinduced anisotropy (order parameter of molecular alignment > 0.5). Moreover, efficient photoinduced surface‐relief‐grating (SRG) formation occurs upon irradiation with a light interference pattern, with a surface‐modulation depth 2.4 times the initial film thickness. This is the first report on a halogen‐bonded photoresponsive low‐molecular‐weight complex, which furthermore combines a high degree of photoalignment and extremely efficient SRG formation in a unique way. This study highlights the potential of halogen bonding as a new tool for the rational design of high‐performance photoresponsive suprastructures. 相似文献