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Asphalt materials including binder, mortar, and mixture are extensively used in the field of pavement engineering considering their obvious viscoelastic properties. To study the phase-transition temperature (Tp) of asphalt materials, we apply dynamic mechanical analysis (DMA) to conduct several temperature-sweep mode tests and compare the Tp values among these materials with similar sizes. Meanwhile, 27 AC5 mixtures are tested to determine the impact of binder type, gradation and, binder content on Tp. Results indicate that the Tp of binder and mortar is negative, but that of mixture is positive. Good correlations among Tp of binder, mortar, and mixture with the same binder type are observed, showing that binder quality is the key factor affecting Tp. Gradation type also affects Tp, and the mixture with a finer gradation has a lower Tp. Among the AC5 asphalt mixtures, the Tp of AR mixture is lower than those of the others, thereby demonstrating better low-temperature performance.

Corresponding experiments were designed and accomplished to obtain the authentic mechanical response mechanism of pavement under different loading conditions. Replicability and reproducibility of the experiments were discussed in this paper. Meanwhile, the response mechanism for three typical pavement structures was analyzed. Results show that mechanical response test method for pavement structure has characteristics of good replicability, reproducibility, and reliability. The method can also be used as an effective way to investigate the mechanical response of pavement structures. The mechanical states of different pavement materials under the same test condition are quite different. For cement bound granular and asphalt concrete, radial strain changes as alternative compression-tension with obvious mechanical response characteristic. However, the situation is different for cement concrete. The region of pavement that is close to the surface is in compressive state. By contrast, the far region is in tensile state. Top-down cracking of pavement developed from top surface crack may appear when load is too heavy. The working state of pavement can be reflected by utilizing the mechanical response test method. The mechanical response test method is a good reference when calculating mechanical state and determining parameters of pavement material.

We report a simple AlOx passivation approach to optimize the device performance of a bilayer graphene/gallium arsenide (BLG/GaAs) Schottky junction based near infrared photodetector (NIRPD). The as-fabricated NIRPD is highly sensitive to NIR illumination at zero bias voltage, with a detectivity of 2.88 × 1011, which is much higher than that without passivation (7.3 × 109 cm Hz1/2 W−1). The corresponding responsivity is 5 mA W−1. Additionally, the surface passivation can substantially increase both the response rate (rise/fall time τr/τf from 32/48 μs to 320/380 ns), and lift time. It is expected that such a self-driven NIRPD with fast response and high detectivity will have great potential in the future optoelectronic devices.

Metal nanoparticles (NPs) induced surface plasmon resonance (SPR) is of great interest for efficient controlling over light׳s propagation and absorption in optoelectronic devices applications. In this work, we proposed a simple strategy to improve the photocurrent of planar silicon (Si) p–n junction solar cells by attaching plasmonic Au nanoparticles (AuNPs) onto transparent graphene film to enhance incident light harvesting. Finite Element Method based simulations reveal that the strong light scattering by AuNPs is responsible for the optical absorption enhancement within Si, leading to the increase in photocurrent. In addition, decoration of AuNPs on graphene also contributes to a high fill factor (FF) by reducing series resistance in the circuit. These contributory factors, together with the effective surface passivation of Si yield a power conversion efficiency (PCE) as high as 10.15%, with excellent reproducibility. This study will open up new opportunities for the optimization of Si based optoelectronic devices.

In this work, we presented a surface mechanical attrition treatment (SMAT)-assisted approach to the synthesis of one-dimensional copper oxide nanowires (CuO NWs) for nanodevices applications. The as-prepared CuO NWs have diameter and the length of 50 ~ 200 nm and 5 ~ 20 μm, respectively, with a preferential growth orientation along [1 0] direction. Interestingly, nanofield-effect transistor (nanoFET) based on individual CuO NW exhibited typical p-type electrical conduction, with a hole mobility of 0.129 cm2V-1 s-1 and hole concentration of 1.34 × 1018 cm-3, respectively. According to first-principle calculations, such a p-type electrical conduction behavior was related to the oxygen vacancies in CuO NWs. What is more, the CuO NW device was sensitive to visible light illumination with peak sensitivity at 600 nm. The responsitivity, conductive gain, and detectivity are estimated to be 2.0 × 102 A W-1, 3.95 × 102 and 6.38 × 1011 cm Hz1/2 W-1, respectively, which are better than the devices composed of other materials. Further study showed that nanophotodetectors assembled on flexible polyethylene terephthalate (PET) substrate can work under different bending conditions with good reproducibility. The totality of the above results suggests that the present CuO NWs are potential building blocks for assembling high-performance optoelectronic devices.

Here we demonstrate a room temperature processed nonvolatile memory device based on an Al/AlO(x)/CdTe:Sb nanowire (NW) heterojunction. Electrical analysis shows an echelon hysteresis composed of a high-resistance state (HRS) and a low-resistance state (LRS), which can allow it to write and erase data from the device. The conductance ratio is as high as 10⁶, with a retention time of 3 × 10⁴ s. Moreover, the SET voltages ranged from +6 to +8 V, whilst the RESET voltage ∼0 V. In addition, flexible memory nano-devices on PET substrate with comparable switching performance at bending condition were fabricated. XPS analysis of the Al/AlO(x)/CdTe:Sb NW heterojunction after controlled Ar⁺ bombardment reveals that this memory behavior is associated with the presence of ultra-thin AlO(x) film. This Al/AlO(x)/CdTe:Sb NW heterojunction will open up opportunities for new memory devices with different configurations.