Top-gated p-type field-effect transistors (FETs) have been fabricated in batch based on carbon nanotube (CNT) network thin films prepared from CNT solution and present high yield and highly uniform ...performance with small threshold voltage distribution with standard deviation of 34 mV. According to the property of FETs, various logical and arithmetical gates, shifters, and d-latch circuits were designed and demonstrated with rail-to-rail output. In particular, a 4-bit adder consisting of 140 p-type CNT FETs was demonstrated with higher packing density and lower supply voltage than other published integrated circuits based on CNT films, which indicates that CNT based integrated circuits can reach to medium scale. In addition, a 2-bit multiplier has been realized for the first time. Benefitted from the high uniformity and suitable threshold voltage of CNT FETs, all of the fabricated circuits based on CNT FETs can be driven by a single voltage as small as 2 V.
Realizing low contact resistance between graphene and metal electrodes remains a well-known challenge for building high-performance graphene devices. In this work, we attempt to reduce the contact ...resistance in graphene transistors and further explore the resistance limit between graphene and metal contacts. The Pd/graphene contact resistance at room temperature is reduced below the 100 Ω·μm level both on mechanically exfoliated and chemical-vapor-deposition graphene by adopting high-purity palladium and high-quality graphene and controlling the fabrication process to not contaminate the interface. After excluding the parasitic series resistances from the measurement system and electrodes, the retrieved contact resistance is shown to be systematically and statistically less than 100 Ω·μm, with a minimum value of 69 Ω·μm, which is very close to the theoretical limit. Furthermore, the contact resistance shows no clear dependence on temperature in the range of 77-300 K; this is attributed to the saturation of carrier injection efficiency between graphene and Pd owing to the high quality of the graphene samples used, which have a sufficiently long carrier mean-free-path.
A weigh-in-motion (WIM) system continuously and automatically detects an object's weight during transmission. The WIM system is used widely in logistics and industry due to increasing labor and time ...costs. However, the accuracy and stability of WIM system measurements could be affected by shock and vibration under high speed and heavy load. A novel six degrees-of-freedom (DOF), mass-spring damping-based Kalman filter with time scale (KFTS) algorithm was proposed to filter noise due to the multiple-input noise and its frequency that is highly coupled with the basic sensor signal. Additionally, an attention-based long short-term memory (LSTM) model was built to predict the object's mass by using multiple time-series sensor signals. The results showed that the model has superior performance compared to support vector machine (SVM), fully connected network (FCN) and extreme gradient boosting (XGBoost) models. Experiments showed this improved deep learning model can provide remarkable accuracy under different loads, speed and working situations, which can be applied to the high-precision logistics industry.
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•We investigated the reaction kinetics of phenols in flowing aerated solutions.•The diffusion and activation controlled reactions caused by an APPJ were characterized.•The ...energy-efficiency ratios for phenol and p-nitrophenol degradation were determined.
In this paper, we propose a method for removing phenols and p-nitrophenols (PNPs) from flowing aqueous solutions generated by atmospheric pressure plasma jets (APPJs). For analyzing the removal characteristics, multiple techniques were used, including flow speed analysis of the aerated solution, optical emission spectroscopy (OES), and liquid chromatography. In addition, the reaction kinetics of diffusion and activation control processes were evaluated using aerated fluid speed variation and the corresponding activation energy. From these results, the relative intensities of hydroxyl radicals produced by an APPJ in water were found to be stronger than those in air and to decrease with increasing flow speed. Furthermore, the reaction kinetics were found to be diffusion-controlled when the solution flow speed was low and activation-controlled under high solution flow speed. It was also found that the degradation efficiency was enhanced with increasing flow speed, which increased the discharge voltage and temperature of the solution and changed the initial pH value when TiO2/UV catalysis was used. From the complex relationship between the reactive species, fluid diffusion, and discharge parameters in wastewater described herein, it is anticipated that these findings will facilitate new approaches to both the design and optimization of discharge reactors intended for wastewater treatment.
Grains and grain boundaries (GBs) in graphene are vital for the control of its properties; however, engineering or controlling them by growth remains a great challenge. Here we discover that the ...dynamic formation of GBs within chemical vapor deposited polygonal graphene flakes is described by a geometric rule. A GB is formed to be symmetrically tilted and a continuous straight line, and the key parameters including end point, direction of GB line, and misorientation angles between adjacent graphene grains can be determined solely by the geometries of the polygonal graphene flakes. We also show the growth control over the length of straight graphene GB lines and demonstrate the capability of parallel fabrication of field-effect transistor devices across predicted GBs in a straightforward manner. This work constitutes a significant step forward in engineering grains and GBs in graphene.
Due to overuse of plastic products, decomposed microplastics (MPs) are widely spread in aquatic ecosystems, and will cause irreparable harm to the human body through the food chain. Traditional MP ...detection methods require cumbersome sample pre-processing procedures and complex instruments, so there is an urgent demand to develop methods to achieve simple on-site detection. Herein, a simple, sensitive, accurate, and stable MP detection method based on surface-enhanced Raman scattering (SERS) is investigated. Considering the hydrophobic problems of MPs, gold nanoparticle (AuNP) doped filter paper as a flexible SERS substrate is applied to capture MPs in the fiber pores. Benefitting from the electromagnetic (EM) hot spots generated by AuNPs, the Raman signal of MPs can be effectively enhanced. Meanwhile, the flexible SERS substrate has good sensitivity to a minimum detectable concentration of 0.1 g L
−1
for polyethylene terephthalate (PET) in water, and the maximum enhancement factor (EF) can reach 360.5. Furthermore, the practicability of the developed method has been proved by the successful detection of MPs in tap water and pond water. This research provides an easy process, high sensitivity, and good reproducibility method for MP detection.
A simple, sensitive, and stable MPs detection method based on a AuNP doped filter paper SERS substrate has been investigated. The substrate can overcome the hydrophobic problem of MPs, and effectively generate EM hot spots to enhance the Raman signal.
A novel three-dimensional device structure for a carbon nanotube （CNT） fin field-effect transistor （FinFET） is proposed and evaluated. We evaluated the potential of the CNT FinFET compared with a Si ...FinFET at a 22-nm node at the circuit level using three performance metrics including propagation delay, total power dissipation, and energy-delay product （EDP）. Compared with a Si FinFET, the CNT FinFET presents obvious advantages in speed and EDP arising from its almost much larger current density but also results in a higher total power dissipation, especially at a low threshold voltage （V~ = 1/3Vaa）. A suitable improvement in Vth can effectively contribute to a significant suppression of leakage current and power dissipation, and then an obvious optimization is obtained in the EDP with an acceptable sacrifice in speed. In particular, CNT FinFETs with optimized threshold voltages can provide an EDP advantage of approximately 50 times over Si FinFETs under a low supply voltage （Vdd -- 0.4 V）, suggesting great potential for CNT FinFET-based integrated circuits.
•An asymmetric rectangular ring resonator based on graphene nanoribbon has been proposed.•Multiple Fano resonances can be observed in the transmission spectrum.•The sensitivity to background ...refractive index can reach 16494 nm/RIU. This high sensitivity makes the structure a promising biosensor.
In this paper, we present an asymmetric rectangular ring resonator based on graphene nanoribbon. The finite-difference time-domain method for three-dimensional model is used to investigate the multiple Fano resonances which can be observed in the transmission spectrum. We also study the influence of graphene structure parameters and chemical potential on Fano resonance. Furthermore, we explore the application of this structure in refractive index sensing. The sensitivity to background refractive index can reach 16494 nm/RIU. This high sensitivity makes the structure a promising biosensor.
Underwater pulsed discharge is widely applied in medicine, machining, and material modification. The induced cavitation bubble and subsequent cavitation collapse are considered the major motivations ...behind these applications. This paper presents an underwater pulsed discharge system. The experimental setup is established to induce and investigate the cavitation bubble assisted with a high-speed camera. Three aspects, including the characteristic of the discharge with different applied voltages and conductivities, the evolution of the cavitation bubble profile, and the energy efficiency of cavitation bubble inducing, are investigated, respectively. Especially, the mechanism of pre-discharge time delay in the low field intensity case is explained using the Joule heat effect. The results show the validity of the underwater pulsed discharger and experimental setup. The present underwater pulsed discharger is proved to be a simple, portable, and easy-to-implement device for the investigation of cavitation bubble dynamics.
Hierarchical graphene architectures (HGAs) that grow by stacking of layers are produced on a liquid copper surface using chemical vapor deposition. The stacking mode — for example ...hexagonal–hexagonal–hexagonal or hexagonal–snowflake–dendritic — can be simply controlled. Measurements of the electrical properties of HGAs indicate that hierarchical stacking of graphene may be a simple and effective way of tailoring their properties without degrading them.
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