Tunable Injection Barrier in Organic Resistive Switches Based on Phase‐Separated Ferroelectric–Semiconductor Blends

Organic non‐volatile resistive bistable diodes based on phase‐separated blends of ferroelectric and semiconducting polymers are fabricated. The polarization field of the ferroelectric modulates the injection barrier at the semiconductor–electrode contact and, hence, the resistance of the comprising diodes. Comparison between the on‐ and off‐current of the switching diodes, with the current measured for semiconductor‐only diodes reveals that the switching occurs between bulk‐limited, i.e., space‐charge‐limited, and injection‐limited current transport. By deliberately varying the HOMO energy of the semiconductor and the work‐function of the metal electrode, it is demonstrated that injection barriers up to 1.6 eV can be surmounted by the ferroelectric polarization yielding on/off current modulations of more than five orders of magnitude. The exponential dependence of the current modulation with a slope of 0.25 eV/decade is rationalized by the magnitude of the injection barrier.     

Network coding-based protection of many-to-one wireless flows

This paper addresses the problem of survivability of many-to-one flows in wireless networks, such as wireless mesh networks (WMNs) and wireless sensor networks (WSNs). Traditional protection schemes are either resource-hungry like the (1+1) protection scheme, or introduce a delay and interrupt the network operation like the (1 : N) protection scheme. In this paper, we present a network coding-based protection technique that overcomes the deficiencies of the traditional schemes. We derive and prove the necessary and sufficient conditions for our solution on a restricted network topology. Then we relax these connectivity requirements and show how to generalize the sufficient and necessary conditions to work with any other topology. We also show how to perform deterministic coding with {0,1} coefficients to achieve linear independence. Moreover, we discuss some of the practical considerations related to our approach. Specifically, we show how to adapt our solution when the network has a limited min-cut; we therefore define a more general problem that takes this constraint into account, which prove to be NP-complete. Furthermore, we discuss the decoding process at the sink, and show how to make use of our solution in the upstream communication (from sink to sources). We also study the effect of the proposed scheme on network performance. Finally, we consider the implementation of our approach when all network nodes have single transceivers, and we solve the problem through a greedy algorithm that constructs a feasible schedule for the transmissions from the sources.     

High-voltage DMOS integrated circuits using floating-gate protection technique

An efficient low power protection scheme for thin gate oxide of high voltage (HV) DMOS transistor is presented. To prevent gate-oxide breakdown and protect HV transistor, the voltage controlling its gate must be within 5 V from the HV supply. Thus signals from the low voltage domain must be level shifted to control the gate of this transistor. Usually this level shifting involves complex circuits that reduce the speed besides requiring of large power and area. In this paper, a simple and efficient protection technique for gate-oxide breakdown is achieved by connecting a capacitor divider structure to the floating-gate node of HV transistor to increase its effective gate oxide thickness. Several HV circuits, including: positive and negative HV doublers and level-up shifters suitable for ultrasound sensing systems are built successfully around the proposed technique. These circuits were implemented with 0.8 μm CMOS/DMOS HV DALSA process. Simulation and experimental results prove the good functionality of the designed HV circuits using the proposed protection technique for voltages up to 200 V.     

Metallic Nanowire Coupled CsPbBr3 Quantum Dots Plasmonic Nanolaser

Plasmonic nanolasers provide a valuable opportunity for expanding sub-wavelength applications. Due to the potential of on-chip integration, semiconductor nanowire (NW)-based plasmonic nanolasers that support the waveguide mode attract a high level of interest. To date, perovskite quantum dots (QDs) based plasmonic lasers, especially nanolasers that support plasmonic-waveguide mode, are still a challenge and remain unexplored. Here, metallic NW coupled CsPbBr₃ QDs plasmonic-waveguide lasers are reported. By embedding Ag NWs in QDs film, an evolution from amplified spontaneous emission with a full width at half maximum (FWHM) of 6.6 nm to localized surface plasmon resonance (LSPR) supported random lasing is observed. When the pump light is focused on a single Ag NW, a QD-NW coupled plasmonic-waveguide laser with a much narrower emission peak (FWHM = 0.4 nm) is realized on a single Ag NW with the uniform polyvinylpyrrolidone layer. The QDs serve as the gain medium while the Ag NW serves as a resonant cavity and propagating plasmonic lasing modes. Furthermore, by pumping two Ag NWs with different directions, a dual-wavelength lasing switch is realized. The demonstration of metallic NW coupled QDs plasmonic nanolaser would provide an alternative approach for ultrasmall light sources as well as fundamental studies of light matter interactions.     

A new control approach to three-phase active filter for harmonicsand reactive power compensation

This paper deals with a new control scheme for a parallel 3-phase active filter to eliminate harmonics and to compensate the reactive power of the nonlinear loads. A 3-phase voltage source inverter bridge with a DC bus capacitor is used as an active filter (AF). A hysteresis based carrierless PWM current control is employed to derive the switching signals to the AF. Source reference currents are derived using load currents, DC bus voltage and source voltage. The command currents of the AF are derived using source reference and load currents. A 3-phase diode rectifier with capacitive loading is employed as the nonlinear load. The AF is found effective to meet IEEE-519 standard recommendations on the harmonics level     

Tunable Thermoelectric Performance in Porous Armchair Graphene Nanoribbons as a Function of Strain,Pore Morphology and Temperature

In this paper, the thermoelectric performance of porous armchair graphene nanoribbons under tensile and compressive strain is investigated as a function of pore morphology and temperature. For all the porous structures irrespective of their pore size, the performance improves at a compressive strain of 10%, while for tensile nature, the minimum cut-off strain required for improved thermoelectric figure of merit (ZT) shows an inverse relation with the pore size. In addition, optimal pore shape geometry can yield better performance, even at lower values of strain. Further analysis reveals that tensile strain is not able to improve the performance at low and intermediate temperatures of around 300 K, whereas tensile/compressive strain is effective in enhancing the performance of porous armchair graphene nanoribbons at higher temperatures. Furthermore, the structures are found to be more sensitive to compressive strain than the tensile one since the effect of compressive strain is found to improve ZT more significantly. Our analysis based on Non-Equilibrium Green’s function calculations suggests a possible route for tailoring the functionality of nanomaterials so as to achieve great potentials for thermoelectric applications at various temperatures.     

A Comparison Study Between Pre-Equalization Schemes for Single and Multi Carrier Modulation Systems

In this paper, frequency domain pre-equalization (Pre-FDE) is developed for broadband cyclic prefix-code division multiple access (CP-CDMA) as a single carrier transmission scheme, and for multi carrier-CDMA (MC-CDMA) and orthogonal frequency division multiplexing (OFDM) as multi carrier transmission schemes. A comparison study is held between these schemes and the traditional equalization schemes. Experimental results show that pre-equalization improves significantly the performance of the single and multi carrier communication systems with a very low complexity at the receiver. The comparative study between MIMO pre-equalization for single carrier systems and for multi carrier systems shows that MIMO pre-equalization for single carrier systems outperforms that for multi carrier systems in terms of bit error rate (BER) performance since single carrier transmission has more frequency diversity than multi carrier transmission in the uncoded case.     

Dearomatization of Diesel by Solvent Extraction: Influence of the Solvent Ratio and Temperature on Diesel Raffinate Properties

To comply with the stringent environmental regulations concerning the quality of fuels the production of ultra low sulfur fuels is obligatory. Consequently, the removal of aromatics from fuels has turned to be a serious issue. This is due to the fact that the presence of aromatics in fuel deters the ultra-low sulfur fuel production. Therefore the researcher’s interest has involved the dearomatization of fuels. As a result of the dearomatization, the quality of fuels improves tremendously. Here, solvent extraction was performed to dearomatize a feedstock sample with 20.1% aromatic and 166 ppm sulfur using acetonitrile. The extraction was performed at low temperature and ambient atmospheric pressure. The aromatic contents were determined via HPLC, while the ASTM methods were employed in other parameters determination. The results showed 72% minimum yield, 8.6% aromatic content, 58–64 cetane index, 73.2 ppm sulfur content, 5.4 viscosity, RI 1.4535, aniline point 82.15, specific gravity 0.824–0.812 with API 40.32–42.88 and flash point 70–78°C. The boiling range of the produced diesel fraction raffinate (172–373°C) that corresponds to C₈–C₂₄ cuts render it a potential candidate for other petrochemical applications.     

Investigation of directly suspended droplet micro extraction method for extraction of trihalomethane and halomethane in water samples

Simple and efficient directly suspended droplet micro extraction (DSDME) in conjunction with gas chromatography-electron capture detector (GC-ECD) has been developed for extraction and determination of Halomethane and Trihalomethane from water samples. In this technique a micro drop of n-hexane is delivered to the surface of an aqueous sample while being agitated by a stirring bar in the bulk of solution. Factors relevant to the extraction efficiency were studied and optimized. The optimized extraction conditions were extraction solvent: n- hexane; NaCl concentration: 1 M; solvent extraction volume: 50 μL; stirring rate: 720 rpm and the extraction time: 5 min. The detection limits of the method were in the range of 0.059–0.137 µg L^?1, relative standard deviation (n = 3) range were 0.019–0.048%. A good linearity (r² ≥ 0.997) and a relatively broad dynamic linear range (10–200 µg L^?1) were obtained and recoveries of method were in the range of 97.69–99.51%. Finally, the proposed method was successfully utilized for pre concentration and determination of halo methane in different real samples. Successfully DSDME technique combined with capillary GC-ECD for the analysis of THMs and HMs in the water investigated samples.     

Metal Organic Framework-MXene Nanoarchitecture for Fast Responsive and Ultra-Stable Electro-Ionic Artificial Muscles

Electro-ionic soft actuators, capable of continuous deformations replacing non-compliant rigid mechanical components, attract increasing interest in the field of next-generation metaverse interfaces and soft robotics. Here, a novel MXene (Ti₃C₂T_x) electrode anchoring manganese-based 1,3,5-benzenetricarboxylate metal-organic framework (MnBTC) for ultrastable electro-ionic artificial muscles is reported. By a facile supramolecular self-assembly, the Ti₃C₂T_x-MnBTC hybrid nanoarchitecture forms coordinate bond, hydrogen bond, and hydrophilic interaction with the conducting polymer of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), resulting in a mechanically flexible and electro-ionically active electrode. The superior electrical and electrochemical performances of the electrode stem from the synergistic effects between intrinsically hierarchical nanoarchitecture of MnBTC and rapid electron transport behavior of Mxene, leading to fast diffusion and accommodation of ions in the ion-exchangeable membrane. The developed artificial muscle based on Ti₃C₂T_x-MnBTC is found to exhibit high bending displacement (12.5 mm) and ultrafast response time (0.77 s) under a low driving voltage (0.5 V), along with wide frequency response (0.1–10 Hz) and exceptional stability (98% retention at 43,200 s) without any distortion of actuation performance. Furthermore, the designed electro-active artificial muscle is successfully used to demonstrate mimicry of eye motions including eyelid blinking and eyeball movement in a doll.