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《Organic Electronics》2014,15(1):216-225
We report an easy, one step, low cost method to obtain a hybrid composite material consisting in graphene quantum dots (GQDs) embedded in a polymeric – poly(ethylene glycol) bis (carboxymethyl) ether – matrix. Optical measurements show the excitation wavelength dependent photoluminescence of the GQDs – PEG600. In comparison with self-passivated GQDs, the composite exhibits a blue shifted photoluminescence, as well as additional emission peaks in the range of 570–600 nm. These features are explained by the presence of new electronic surface states induced by the polymeric matrix as it was demonstrated by the electrochemical measurements. The transport properties consist in a large clockwise hysteresis presenting high and low resistance states, also two distinctive regions of negative differential resistance. The photocurrent decay and the transient currents indicate a large charge storage and confirm the existence of trap charge levels. The experimental findings suggest that the leading mechanism underling the transport is Simmons Verderber. We demonstrated the switching properties of GQDs – PEG600 for applications in non-volatile memory by performing standard sequence memory tests. 相似文献
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Sayyeda M. Hasan Landon D. Nash Duncan J. Maitland 《Journal of polymer science. Part A, Polymer chemistry》2016,54(14):1300-1318
Porous shape memory polymers (SMPs) exhibit geometric and volumetric shape change when actuated by an external stimulus and can be fabricated as foams, scaffolds, meshes, and other polymeric substrates that possess porous three-dimensional macrostructures. These materials have applications in multiple industries such as textiles, biomedical devices, tissue engineering, and aerospace. This review article examines recent developments in porous SMPs, with a focus on fabrication methods, methods of characterization, modes of actuation, and applications. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1300–1318 相似文献
104.
Temperature memory effect and its stability revealed via differential scanning calorimetry in ethylene‐vinyl acetate within glass transition range
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Tao Xi Wang Wei Min Huang Hongmei Chen Rui Xiao Hai Bo Lu Shu Feng Kang 《Journal of Polymer Science.Polymer Physics》2016,54(17):1731-1737
In this article, we reveal the temperature memory effect (TME) in a commercial thermoplastic polymer, namely ethylene‐vinyl acetate (EVA), within its glass transition range via a series of differential scanning calorimeter (DSC) tests. In addition, we investigate the influence of heating holding time and also compare the observed TME in current study with that of shape memory alloys (SMAs). It is concluded that the TME via DSC (without any macroscopic shape change) is achievable within the glass transition range of a polymer. Conversely, although the observed TME shares the many similar features as those in SMAs, due to the nature of micro‐Brownian motion in the glass transition of polymers, the resulted TME is strongly affected by the heating holding time. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1731–1737 相似文献
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Experiment on relationship between the magnetic gradient of low-carbon steel and its stress 总被引:1,自引:0,他引:1
Xingliang Jian Xingchao Jian Guoyong Deng 《Journal of magnetism and magnetic materials》2009,321(21):3600-3606
In geomagnetic field, a series of tensile experiments on the low-carbon steel sticks were carried out. A special homemade detector was used to measure the magnetic gradient on the material surface. The results showed that the relationship between the magnetic gradient and the stress varied with different conditions of measurement. There was no obvious correlation between the magnetic gradient and the tensile stress if the sample remained on the material test machine. If the sample was taken off from the machine, the measured magnetic gradient was linear with the prior maximum stress. In Nanjing, PR China, a place of 32°N latitude, the slope of the linear relationship was about 67 (uT/m)/MPa. This offered a new method of non-destructive stress testing by measuring the magnetic gradient on the ferromagnetic component surface. The prior maximum applied stress of the sample could be tested by measuring the present surface magnetic gradient. Actually this phenomenon was the metal magnetic memory (MMM). The magnetic gradient near the stress concentration zone of the sample, the necking point, was much larger than other area. Thus, the hidden damage in the ferromagnetic component could be detected early by measuring the magnetic gradient distribution on its surface. In addition, the magnetic memory signal gradually weakened as the sample was taken off and laid aside. Therefore, it was effective for a given period of time to detect the stress or stress concentration based on the MMM testing. 相似文献
107.
The crystallization kinetics of Sn40Se60 thin films has been successfully investigated using sheet resistance versus temperature measurements. Thermal evaporation was used to deposit the films on ordinary glass substrates. The crystallization temperature for Sn40Se60 thin film was found to be 156.6 ± 0.3 ℃. In the as-deposited state, the sheet resistance was found to be 195 MΩ, this value declined to 1560 Ω/口 upon annealing. The value of activation energy obtained from the Kissinger plot was 0.62 ± 0.07 eV. From the results obtained, Sn40Se60 is a promising alloy for PCM application because of its high electrical contrast, high crystallization temperature, and relatively high activation energy. 相似文献
108.
我们报道了一种“金属-量子点-金属”结构的自对准制备方法。该方法主要包括“电子束曝光-薄膜淀积-刻蚀”工艺,具有套刻容限大、开发周期短以及可兼容多种材料等优点,尤其适用于具有类似结构的纳米器件制备。该方法中使用的牺牲层工艺和强化版图,降低了剥离工艺的难度,提升了可制备器件结构的力学强度。最后,作为应用实例,我们用该方法制备了尺寸为 255 nm × 45 nm × 30 nm( 长 × 宽 × 高)的相变节点。 相似文献
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