Novel Efficient Circuit Design for Multilayer QCA RCA

The novel emerging technology, QCA technology, is a candidate for replacing CMOS technology. Full Adder (FA) circuits are also widely used circuits in arithmetic circuits design. In this paper, two new multilayer QCA architectures are presented: one-bit FA and 4-bit Ripple Carry Adder (RCA). The designed one-bit multilayer FA architecture is based on a new XOR gate architecture. The designed 4-bit multilayer QCA RCA is also developed based on the designed one-bit multilayer QCA FA. The functionality of the designed architectures are verified using QCADesigner tool. The results indicate that the designed architecture for 4-bit multilayer QCA RCA requires 5 clock phases, 125 QCA cells, and 0.17 μm² area. The comparison results confirm that the designed architectures provide improvements compared with other adder architectures in terms of cost, cell count, and area.

     

Counters Designs with Minimum Number of Cells and Area in the Quantum-Dot Cellular Automata Technology

The quantum-dot cellular automata (QCA) were highly regarded due to its high operating frequency and significantly low power consumption. One of the most useful circuits in processors architecture is counter. This paper presents effective designs and arrangement of QCA based counter-circuits. In this study new counter circuits in QCA technology are designed and precise simulation are done using the QCADesigner. Three, four and five bits counters are proposed in this paper in QCA technology. A comparison is made between the past and recent designs to illustrate which method is better and more efficient in terms of area, complexity, number of cells, and delay. For example, the proposed three bit shift register has 174 quantum cells, 0.2μm² occupied area and three QCA clock cycles delay.

     

Towards Multilayer QCA SISO Shift Register Based on Efficient D-FF Circuits

Quantum-dot Cellular Automata (QCA) is a new technology for replacing CMOS technology at nano-scale dimansion. Shift registers have commonly used circuit in the digital circuits design. In this paper, a new 3-bit Serial Input-Serial Output (SISO) QCA shift register is presented. The proposed circuit uses 3 novel D-Flip-Flops (D-FFs) that are developed in this paper. The proposed circuits are implemented by using QCADesigner tool version 2.0.3. The developed QCA SISO shift register has 120 cells and 0.03 μm² area. The results show that the developed circuits have advantages compared to other QCA circuits in terms of area.     

RETRACTED ARTICLE: A New Design of 2-Bit Universal Shift Register Using Rotated Majority Gate Based on Quantum-Dot Cellular Automata Technology

Quantum-dot Cellular Automata (QCA) is emerging nanotechnology that can represent binary information using quantum cells without current flows. It is known as a promising alternative of Complementary Metal–Oxide Semiconductor (CMOS) to solve its drawbacks. On the other hand, the shift register is one of the most widely used practical devices in digital systems. Also, QCA has the potential to achieve attractive features than transistor-based technology. However, very small-scale and Nano-fabrication limits impose a hurdle to the design of QCA-based circuits and necessitate for fault-tolerant analysis is appeared. Therefore, the aim of this paper is to design and simulate an optimized a D-flip-flop (as the main element of the shift register) based on QCA technology, which is extended to design an optimized 2-bit universal shift register. This paper evaluates the performance of the designed shift register in the presence of the QCA fault. Collected results using QCADesigner tool demonstrate the fault-tolerant feature of the proposed design with minimum clocking and area consumption.

     

Design of Cost-Efficient QCA Reversible Circuits via Clock-Zone-Based Crossover

Nanotechnologies, remarkably Quantum-dot Cellular Automata (QCA), offer an attractive perspective for future computing technologies. In this paper, QCA is investigated as an implementation method for reversible logic. A novel Reversible Gate is developed using QCA technology. Performance of the proposed gate is verified using thirteen standard three variables Boolean functions, which demonstrate from 14.3% to 42.8% superiority in term of gate counts obtained with other reversible gates. Proposed reversible gate requires switching and leakage energy dissipation of 0.168 eV and 0.271 eV, respectively, at 1.5 E_k energy level. The proposed gate uses 146 cells occupying only 0.14 μ m² area and then used to design a full adder. We use a coplanar QCA crossover architecture in the designs that uses non-adjacent clock zones for the two crossing wires. These designs have been realized with QCADesigner.     

Designing Nanoscale Counter Using Reversible Gate Based on Quantum-Dot Cellular Automata

Some new technologies such as Quantum-dot Cellular Automata (QCA) is suggested to solve the physical limits of the Complementary Metal-Oxide Semiconductor (CMOS) technology. The QCA as one of the novel technologies at nanoscale has potential applications in future computers. This technology has some advantages such as minimal size, high speed, low latency, and low power consumption. As a result, it is used for creating all varieties of memory. Counter circuits as one of the important circuits in the digital systems are composed of some latches, which are connected to each other in series and actually they count input pulses in the circuit. On the other hand, the reversible computations are very important because of their ability in reducing energy in nanometer circuits. Improving the energy efficiency, increasing the speed of nanometer circuits, increasing the portability of system, making smaller components of the circuit in a nuclear size and reducing the power consumption are considered as the usage of reversible logic. Therefore, this paper aims to design a two-bit reversible counter that is optimized on the basis of QCA using an improved reversible gate. The proposed reversible structure of 2-bit counter can be increased to 3-bit, 4-bit and more. The advantages of the proposed design have been shown using QCADesigner in terms of the delay in comparison with previous circuits.     

Potential-induced sonoelectrochemical graphene nanosheets with vacancies as hydrogen peroxide reduction catalysts and sensors

Defective graphene nanosheets (dGN_4V) with 5-9, 5-8-5, and point defects were synthesised by a sonoelectrochemical method, where a potential of 4 V (vs. Ag/AgCl) was applied to drive the rapid intercalation of phosphate ions between the layers of the graphite foil as a working electrode. In addition to these vacancies, double vacancy defects were also created when the applied potential was increased to 8 V (dGN_8V). The defect density of dGN_8V (2406 μm⁻²) was higher than that of dGN_4V (1786 μm⁻²). Additionally, dGN_8V and dGN_4V were applied as catalysts for the hydrogen peroxide reduction reaction (HPRR). The mass activity of dGN_8V (1.31 × 10⁻² mA·μg⁻¹) was greater than that of dGN_4V (1.17 × 10⁻² mA·μg⁻¹) because of its high electrochemical surface area (ECSA, 1250.89 m²·g⁻¹) and defect density (N_D, 2406 μm⁻²), leading to low charge transfer resistance on the electrocatalytic interface. The ECSA and N_D of dGN_4V were 502.7 m²·g⁻¹ and 1786 μm⁻², respectively. Apart from its remarkable HPRR activity, the cost-effective dGN_8V catalyst also showed potential as an amperometric sensor for the determination of H₂O₂.     

A Power-Efficient Single Layer Full Adder Design in Field-Coupled QCA Nanocomputing

As an emerging technology device, Quantum-dot cellular automata (QCA) may be a suitable substitute for traditional semiconductor transistor technology. Arithmetic logic unit in field-coupled QCA has been also studied extensively in recent year. In this paper, the new low-power Exclusive-OR gate is presented, which is mainly based on QCA cellular leveled format. This Exclusive-OR gate can be used to design various useful QCA circuits. By using this gate, we design and implement a novel full adder circuit with low dissipation. The circuit is designed using only 45 normal cells in a single layer without crossover. Compared with previous designs, both decimal adders achieve better performance in terms of latency and overall cost. The operation of the proposed circuit has been verified by QCADesigner version 2.0.3 and energy dissipation investigated by QCAPro tool. We also compared with previous designs in terms of power dissipation, cell-counts, area, latency and cost. The proposed full adder has the smallest area with less number of cells. And the total energy dissipation of our proposed full adder are only 0.05112 eV, 0.07454 eV and 0.10181 eV when tunneling energy levels are 0.5 Ek, 1 Ek and 1.5 Ek, respectively. The proposed single full adder also has the lowest total energy dissipation with a reduction of 20.94, 11.25 and 4.82% in 0.5 E_k, 1 E_k and 1.5 E_k tunneling energy levels, respectively when compared with the previous most power-efficient design.

     

Designing a New 4:2 Compressor Using an Efficient Multi-Layer Full-Adder Based on Nanoscale Quantum-Dot Cellular Automata

Quantum-dot Cellular Automata (QCA) is novel prominent nanotechnology. It promises a substitution to Complementary Metal–Oxide–Semiconductor (CMOS) technology with a higher scale integration, smaller size, faster speed, higher switching frequency, and lower power consumption. It also causes digital circuits to be schematized with incredible velocity and density. The full adder, compressor, and multiplier circuits are the basic units in the QCA technology. Compressors are an important class of arithmetic circuits, and researchers can use quantum compressors in the structure of complex systems. In this paper, first, a novel three-input multi-layer full-adder in QCA technology is designed, and based on it, a new multi-layer 4:2 compressor is presented. The proposed QCA-based full-adder and compressor uses an XOR gate. The proposed design offers good performance regarding the delay, area size, and cell number comparing to the existing ones. Also, in this gate, the output signal is not enclosed, and we can use it easily. The accuracy of the suggested circuits has been assessed with the utilization of QCADesigner 2.0.3. The results show that the proposed 4:2 compressor architecture utilizes 75 cell and 1.25 clock phases, which are efficient than other designs.

     

Comparison of oil-in-water emulsions prepared by ultrasound,high-pressure homogenization and high-speed homogenization

This study was designed to compare the properties of myofibrillar protein (MP) stabilized soybean oil-in-water emulsions fabricated by ultrasound-assisted emulsification (UAE), high-pressure homogenization (HPH) and high-speed homogenization (HSH). The emulsion properties, droplet characteristics, interfacial proteins, protein exposure extent, microrheological properties, multiple light scattering results, and 7 d storage stabilities of the three emulsions were specifically investigated. Our results indicate that UAE and HPH were better emulsification methods than HSH to obtain high-quality emulsions with higher emulsifying activity index (UAE 20.73 m²·g⁻¹, HPH 11.76 m²·g⁻¹ and HSH 6.80 m²·g⁻¹), whiteness (UAE 81.05, HPH 80.67 and HSH 74.09), viscosity coefficient (UAE 0.44 Pa·sⁿ, HPH 0.49 Pa·sⁿ and HSH 0.22 Pa·sⁿ), macroscopic viscosity index (UAE 2.31 nm⁻²·s, HPH 0.38 nm⁻²·s and HSH 0.34 nm⁻²·s), and storage stability, especially for the UAE. Furthermore, UAE was a more efficient emulsification method than HPH to prepare the fine MP-soybean oil emulsion. The protein-coated oil droplets were observed in the three emulsions. The emulsion droplet size of the UAE-fabricated emulsion was the lowest (0.15 μm) while the interfacial protein concentration (93.37%) and the protein exposure extent were the highest among the three emulsions. During the 7 d storage, no separation was observed for the UAE-fabricated emulsion, while the emulsions fabricated by HPH and HSH were separated after storage for 5 d and 2 h. Therefore, this work suggests that UAE could be a better method than HPH and HSH to fabricate MP-soybean oil emulsion.     

Novel tacrine-based acetylcholinesterase inhibitors as potential agents for the treatment of Alzheimer’s disease: Quinolotacrine hybrids

A new series of quinolotacrine hybrids including cyclopenta- and cyclohexa-quinolotacrine derivatives were designed, synthesized, and assessed as anti-cholinesterase (ChE) agents. The designed derivatives indicated higher inhibitory effect on the acetylcholinesterase (AChE) with IC₅₀ values of 0.285–100 µM compared to butyrylcholinesterase (BChE) with IC₅₀ values of?>?100 µM. Of these compounds, cyclohexa-quinolotacrine hybrids displayed a little better anti-AChE activity than cyclopenta-quinolotacrine hybrids. Compound 8-amino-7-(3-hydroxyphenyl)-5,7,9,10,11,12-hexahydro-6H-pyrano[2,3-b:5,6-c'] diquinolin-6-one (6m) including 3-hydroxyphenyl and cyclohexane ring moieties exhibited the best AChE inhibitory activity with IC₅₀ value of 0.285 µM. The kinetic and molecular docking studies indicated that compound 6m occupied both the catalytic anionic site (CAS) and peripheral anionic site (PAS) of AChE as a mixed inhibitor. Using neuroprotective assay against H₂O₂-induced cell death in PC12 cells, the compound 6h illustrated significant protection among the assessed compounds. In silico ADME studies estimated good drug-likeness for the designed compounds. As a result, these quinolotacrine hybrids can be very encouraging AChE inhibitors to treat Alzheimer’s disease.

Graphic abstract

A novel series of quinolotacrine hybrids were designed, synthesized, and evaluated against AChE and BChE enzymes as potential agents for the treatment of AD. The hybrids showed good to significant inhibitory activity against AChE (0.285–100 μM) compared to butyrylcholinesterase (BChE) with IC₅₀ values of?>?100 μM. Among them, compound 8-amino-7-(3-hydroxyphenyl)-5,7,9,10,11,12-hexahydro-6H-pyrano[2,3-b:5,6-c′] diquinolin-6-one (6 m) bearing 3-hydroxyphenyl moiety and cyclohexane ring exhibited the highest anti-AChE activity with IC₅₀ value of 0.285 μM. The kinetic and molecular docking studies illustrated that compound 6 m is a mixed inhibitor and binds to both the catalytic anionic site (CAS) and peripheral anionic site (PAS) of AChE.

     

A Cost-Aware Efficient RAM Structure Based on Quantum-Dot Cellular Automata Nanotechnology

Nowadays quantum-dot cellular automata (QCA) as a nanoscale transistor-less device technology have attained major attention for their prominent features. The circuits constructed by QCA technology owning remarkable decreasing in size, fast switching speed and ultra-low energy consumption. These features can be more different in varied memory structures. Random access memory (RAM) is a kind of data storage devices that allows data to be read or written it’s generally volatile, and used for data that change often. Due to the significance of memory in a digital system, designing and optimization of high-speed RAM in QCA nanotechnology is a substantial subject. So, this paper presents a new structure for QCA-based RAM cell by employing the 3-input rotated majority gate (RMG). Eventually, 1 × 4 RAM is designed by exerting the individual memory cell. The functionality of the proposed design is implemented and assessed using the QCADesigner simulator. The obtained results demonstrated that the designed QCA-based RAM cell is superior to previous structures in terms of delay and cell count.

     

Flexible thermoelectric module based on zinc oxide thin film grown via SILAR

In this work, we used the low temperature solution growth Successive Ionic Layer Adsorption and Reaction (SILAR) for a deposition of the nanostructured undoped and indium doped (ZnO and ZnO:In) thin films on flexible polyimide (PI) substrates for their use as cheap non-toxic thermoelectric materials in the flexible thermoelectric modules of planar type to power up portable and wearable electronics and miniature devices. The use of a zincate solution in the SILAR method allows to obtain ZnO:In film, which after post-growth annealing at 300 °C has low resistivity ρ ≈ 0.02 Ω m, and high Seebeck coefficient −147 μV/K and thermoelectric power factor ~1 μW K⁻² m⁻¹ at near-room temperatures. As evidence of the operability of the manufactured films as the basis of the TE device, we have designed and tested experimental lightweight thin-film thermoelectric module. This TE module is able to produce specific output power 0.8 μW/m² at ΔT = 50 K.     

QCA Gray Code Converter Circuits Using LTEx Methodology

The Quantum-dot Cellular Automata (QCA) is the prominent paradigm of nanotechnology considered to continue the computation at deep sub-micron regime. The QCA realizations of several multilevel circuit of arithmetic logic unit have been introduced in the recent years. However, as high fan-in Binary to Gray (B2G) and Gray to Binary (G2B) Converters exist in the processor based architecture, no attention has been paid towards the QCA instantiation of the Gray Code Converters which are anticipated to be used in 8-bit, 16-bit, 32-bit or even more bit addressable machines of Gray Code Addressing schemes. In this work the two-input Layered T module is presented to exploit the operation of an Exclusive-OR Gate (namely LTEx module) as an elemental block. The “defect-tolerant analysis” of the two-input LTEx module has been analyzed to establish the scalability and reproducibility of the LTEx module in the complex circuits. The novel formulations exploiting the operability of the LTEx module have been proposed to instantiate area-delay efficient B2G and G2B Converters which can be exclusively used in Gray Code Addressing schemes. Moreover this work formulates the QCA design metrics such as O-Cost, Effective area, Delay and Cost _α for the n-bit converter layouts.     

A New Coplanar Design of Multiplier Based on Nanoscale Quantum-Dot Cellular Automata

Quantum-dot cellular automata (QCA) nanotechnology is emerging as a replacement technique for maintaining increasing microprocessor performance and it yields small size, high speed, and low power consumption. On the other hand, a multiplier is a circuit that multiplies two binary values for performing sequential addition operations and accumulating the results. This type of circuit is the basic structural unit of many arithmetic logical units, digital signal processing, and communication system. The multiplier circuit contains some full adders that can perform add operations, so, it is very important that low-complexity full adders are used. Therefore, in this paper, a new 2 × 2 array multiplier circuit in QCA by employing an efficient structure of full adder is designed and implemented. This design is constructed using coplanar layouts and compared its performance with existing QCA multipliers. The operation and efficiency of the proposed structure have been confirmed using QCADesigner tool. The simulation results have demonstrated that the 2 × 2 multiplier leads to less cell count and area as the prime designing factors.

     

Robust Coplanar Full Adder Based on Novel Inverter in Quantum Cellular Automata

Quantum dot cellular automata (QCA) is one of the nano-scale computing paradigms which promises high speed and ultra-low power consumption. Since the one-bit full adder is a fundamental building block of arithmetic circuits, designing an efficient QCA full adder cell is very imperative in this new technology. In this paper, we propose a QCA full adder using a new inverter gate which leads to reduced complexity and area occupation. The proposed layout is simulated by the QCA designer engines. We also provide a performance comparison of our proposed QCA full adder with the previous relevant designs. Furthermore, a detailed analysis of energy dissipation is performed which demonstrates the superiority of the proposed design in terms of the energy efficiency.

     

High LO-to-RF isolation 94 GHz coplanar monolithic down-converter for FMCW radar sensor applications

This paper presents a 94 GHz monolithic down-converter with low conversion loss and high local oscillator (LO)-to-RF isolation using the 0.1 μm T-gate metamorphic high electron-mobility transistor (MHEMT) technology. The down-converter consists of a one-stage amplifier and a single-balanced mixer based on the high-directivity tandem coupler structure using the air-bridge crossovers, thereby amplifying the RF signals and maximizing the LO-to-RF isolation by using an inherent S₁₂ isolation characteristic of the amplifier and good phase balance of the tandem coupler. The fabricated one-stage amplifier using a 30 μm × 2 MHEMT shows a small signal gain of 7 dB at 94 GHz. The single-balanced mixer comprising two 20 μm × 2 MHEMT Schottky diodes and the tandem coupler with an additional λ/4-length line exhibits the conversion loss less than 7.8 dB and the LO-to-RF isolation higher than 30 dB in a RF frequency range of 91–96 GHz. Two circuits designed both for a 50 Ω impedance system are integrated into the down-converter of a 2.6 × 2.5 mm² chip size, and it shows a low conversion loss of ∼1 dB at 94 GHz and excellent LO-to-RF isolation above 40 dB in a frequency range of 90–100 GHz. This is the best isolation among the W-band monolithic down-converters reported to date.     

Interaction of Folic Acid with Mn2+ Doped CdTe/ZnS Quantum Dots: In Situ Detection of Folic Acid

To utilize the nanomaterials as an effective carrier for the drug delivery applications, it is important to study the interaction between nanomaterials and drug or biomolecules. In this study GSH functionalized Mn²⁺-doped CdTe/ZnS QDs has been utilized as a model nanomaterial due to its high luminescence property. Folic acid (FA) gradually quenches the FL of GSH functionalized Mn²⁺???doped CdTe/ZnS QDs. The Stern-Volmer quenching constant (K_sv), binding constant (K_s) and effective quenching constant (Ka) for the FA-QDs system is calculated to be 1.32?×?10⁵ M^?1, 1.92?×?10⁵ and 0.27?×?10⁵ M^?1, respectively under optimized condition (Temp. 300 K, pH 8.0, incubation time 40 min.). The effects of temperature, pH, and incubation time on FA-QDs system have also been studied. Statistical analysis of the quenched FL intensity versus FA concentration revealed a linear range from 1?×?10^?7 to 5.0?×?10^?5 for FA detection. The LOD of the current nano-sensor for FA was calculated to be 0.2 μM. The effect of common interfering metal ions and other relevant biomolecules on the detection of FA (12.0 μM) have also been investigated. L-cysteine and glutathione displayed moderate effect on FA detection. Similarly, the common metal ions (Na⁺, K⁺, Ca²⁺ and Mg²⁺) produced minute interference while Zn²⁺ Cu²⁺ and Fe³⁺ exert moderate interference. Toxic metal ions (Hg²⁺ and Pb²⁺) produced severe interferences in FA detection.

Graphical abstract

GSH-Mn²⁺ CdTe/ZnS QDs based Fluorescence Nanosensor for Folic acid

     

Ultrasonic and DFT study of intermolecular association through hydrogen bonding in aqueous solutions of d(−)-arabinose

The experimental measurements of density, viscosity and ultrasonic velocity of aqueous d-arabinose solutions were carried out as functions of concentration (0.1 ≤ m [mol kg^? 1] ≤ 1.0) and temperature (303.15 ≤ T [K] ≤ 323.15). The isentropic compressibility (β_s), acoustic impedance (Z), hydration number (H_n), intermolecular free length (L_f), classical sound absorption (α/f²)_class and shear relaxation time (τ) were calculated by using the measured data. These parameters have been interpreted in terms of solute–solvent interactions. The quantum chemical calculations were performed to study the hydrogen bonding in interacting complex formed between α-D-arabinopyranose in ¹C₄ conformation and water molecules. Computations have been done by using Density Functional Theory (DFT) method at B3LYP/6-31+g(d) level of theory to study the equilibrium structure of α-d-arabinose, α-D-arabinopyranose–water interacting complex and vibrational frequencies. The solution phase study was carried out using Onsager's reaction field model in water solvent. The computed and scaled vibrational frequencies are in good agreement with the main features of the experimental spectrum when seven water molecules are considered explicitly with α-D-arabinopyranose in ¹C₄ conformation. The interaction energy (E_total), hydrogen bond lengths and dipole moment (μ_m) of the interacting complex are also presented and discussed with in the light of solute–solvent interactions.     

Compact WDM demultiplexer for seven channels in photonic crystal

We demonstrate a new device concept for wavelength division demultiplexing based on planar photonic crystal waveguides. The filtering of wavelength channels is realized by shifting the cutoff frequency of the fundamental photonic bandgap mode in consecutive sections of the waveguide. The shift is realized by modifying the size of the border holes.The proposed demultiplexer has an area equal to (16.5 μm × 6.5 μm) and thus it is verified that this structure is very small and can be integrated easily into optical integrated circuits with nanophotonic technologies. The output wavelengths of designed structure can be tuned for communication applications, around 1550 nm. The wavelengths of demultiplexer channels are λ₁ = 1.590 μm, λ₂ = 1.566 μm, λ₃ = 1.525 μm, λ₄ = 1.510 μm, λ₅ = 1.484 μm, λ₆ = 1.450 μm, λ₇ = 1.400 μm respectively. Designs offering improvement of number of the separate wavelengths (seven), miniaturization of the structure (107.25 μm²) is our aim in this work.In our structure, we consider that the 2D triangular lattice photonic crystal is composed of air holes surrounded by dielectric. Its parameters are: radius of holes (r = 0.130 μm), lattice constant (a = 0.380 μm), and index of membrane (n = 3.181:InP). The numerical model used to simulate the structure of the demultiplexer is based on the finite difference time domain (FDTD).