Complex Logic Operations Research Articles

All-Optic Logical Operations Based on the Visible-Near Infrared Bipolar Optical Response.

The burgeoning need for extensive data processing has sparked enthusiasm for the development of a novel optical logic gate platform. In this study, junction field-effect phototransistors based on molybdenum disulfide/Germanium (MoS2/Ge) heterojunctions are constructed as optical logic units. This device demonstrates a positive photoresponse that is attributed to the photoconductivity effect occurring upon irradiation with visible (Vis) light. Under the illumination of near-infrared (NIR) optics with wavelengths within the communication band, the device shows a negative photoresponse, which is associated with the interlayer Coulomb interactions. The current state of the device can be effectively modulated as different logical states by precisely tuning the wavelength and power density of the optical. Within a 3×3 MoS2/Ge phototransistor array, five essentially all-optical logic gates ("AND," "OR," "NAND," "NOT," and "NOR") can be achieved in every signal unit. Furthermore, three complex all-optical logical operations are demonstrated by integrating two MoS2/Ge phototransistors in series. Compared to electronic designs, these all-optical logic devices offer a significant reduction in transistor number, with savings of 50-94% when implementing the above-mentioned functions. These results present opportunities for the development of photonic chips with low power consumption, high fidelity, and large volumes.

Photo-switching operation of MoS2 field effect transistor by photoisomerization of azobenzene in solution delivered on a microfluidic platform

Combining the photoisomerization of molecules with an electrical device is important for developing optoelectronic devices. Field effect transistors (FETs) with atomically thin channels are suitable for this purpose because the FET properties respond to chemical changes in molecules. Since the photoisomerization wavelength of the switching molecules can be tuned, complex logic operations can be realized if a specific molecule is delivered to the target FET of an integrated circuit. However, conventional techniques for transferring molecules, such as drop casting and sublimation, cannot efficiently realize this goal. In this study, we fabricated a MoS2 FET device combined with a microfluidic platform, wherein the MoS2 channel was in contact with the flow of an azobenzene solution in isopropyl alcohol as the solvent. UV radiation (365 nm) and thermal relaxation realize the cycle of trans- and cis-azobenzene states and the switching of the substantial FET properties. This study demonstrated the feasibility of using the solution for optical switching of the MoS2-FET, which can realize quick phase changes in the molecule and the delivery of the molecule to the target FET by a microfluidic platform.

Heteromultivalent DNA Enhances the Assembly Yield of Hybrid Nanoparticles and Facilitates Dynamic Disassembly for Bioanalysis Using ICP-MS.

To obtain enhanced physical and biological properties, various nanoparticles are typically assembled into hybrid nanoparticles through the binding of multiple homologous DNA strands to their complementary counterparts, commonly referred to as homomultivalent assembly. However, the poor binding affinity and limited controllability of homomultivalent disassembly restrict the assembly yield and dynamic functionality of the hybrid nanoparticles. To achieve a higher binding affinity and flexible assembly choice, we utilized the paired heteromultivalency DNA to construct hybrid nanoparticles and demonstrate their excellent assembly characteristics and dynamic applications. Specifically, through heteromultivalency, DNA-functionalized magnetic beads (MBs) and gold nanoparticles (AuNPs) were efficiently assembled. By utilizing ICP-MS, the assembly efficiency of AuNPs on MBs was directly monitored, enabling quantitative analysis and optimization of heteromultivalent binding events. As a result, the enhanced assembly yield is primarily attributed to the fact that heteromultivalency allows for the maximization of effective DNA probes on the surface of nanoparticles, eliminating steric hindrance interference. Subsequently, with external oligonucleotides as triggers, it was revealed that the disassembly mechanism of hybrid nanoparticles was initiated, which was based on an increased local concentration rather than toehold-mediated displacement of paired heteromultivalency DNA probes. Capitalizing on these features, an output platform was then established based on ICP-MS signals that several Boolean operations and analytical applications can be achieved by simply modifying the design sequences. The findings provide new insights into DNA biointerface interaction, with potential applications to complex logic operations and the construction of large DNA nanostructures.

Mechanical logic gate design based on multi-stable metamaterial with multi-step deformation

Mechanical metamaterials exhibit remarkable design versatility, enabling a series of unconventional mechanical properties via structural modifications. However, it is worth noting that many existing mechanical metamaterials either possess a singular deformation path or only multi-step deformation paths without reusability. This study proposes a novel multi-step deformation metamaterial that possesses multiple stable configurations. This metamaterial produces a unique two-step deformation mode under displacement loading, where the curved beams of the unit cells undergo snap-through and the vertical beams buckling. The influence of geometrical parameters on the multistability of the structure is thoroughly examined, and a theoretical prediction model for the buckling load is formulated. To validate the accuracy of the model, experimental tests and finite element simulations are conducted on the two-step deformation mode of periodic array of the unit cell. Additionally, a bi-material design approach for the unit cell is further introduced to enhance the specific energy absorption of the structure while reinforce the negative stiffness effect. Leveraging the multistable characteristics of the structure, mechanical logic gates such as AND, OR, NOT and NAND are conceptualized and experimentally validated. Through the implementation of rational designs and combinatorial connections within the logic gate structure, more complex logic operations can be realized.

Towards the development of a DNA automaton: modular RNA-cleaving deoxyribozyme logic gates regulated by miRNAs.

Advancements in DNA computation have unlocked molecular-scale information processing possibilities, utilizing the intrinsic properties of DNA for complex logical operations with transformative applications in biomedicine. DNA computation shows promise in molecular diagnostics, enabling precise and sensitive detection of genetic mutations and disease biomarkers. Moreover, it holds potential for targeted gene regulation, facilitating personalized therapeutic interventions with enhanced efficacy and reduced side effects. Herein, we have developed six DNAzyme-based logic gates able to process YES, AND, and NOT Boolean logic. The novelty of this work lies in their additional functionalization with a common DNA scaffold for increased cooperativity in input recognition. Moreover, we explored hierarchical input binding to multi-input logic gates, which helped gate optimization. Additionally, we developed a new design of an allosteric hairpin switch used to implement NOT logic. All DNA logic gates achieved the desired true-to-false output signal when detecting a panel of miRNAs, known for their important role in malignancy regulation. This is the first example of DNAzyme-based logic gates having all input-recognizing elements integrated in a single DNA nanostructure, which provides new opportunities for building DNA automatons for diagnosis and therapy of human diseases.

Nanoclusters with specific DNA overhangs: modifying configurability, engineering contrary logic pairs and the parity generator/checker for error detection.

The most promising alternative for next-generation molecular computers is biocomputing, which uses DNAs as its primary building blocks to perform a Boolean operation. DNA nanoclusters (NCs) have emerged as promising candidates for biosensing applications due to their unique self-assembly properties and programmability. It has been demonstrated that adding DNA overhangs to DNA NCs improves their adaptability in identifying specific biomolecular interactions. A recent proposal in DNA computing is the concept of "contrary logic pairs (CLPs)" executed by employing a DNA hybrid architecture as a universal platform. We have designed thymine overhang-modified DNA-templated NCs (T-Au/Ag NCs). These NCs serve as a chemosensing ensemble platform, where the presence of HgII ions mediates the formation of M-Au/Ag NCs. The resulting NCs exhibit the capability to drive elementary CLPs (YES, NOT, OR, NOR, INH and IMP) as well as complex logic operations (XOR and XNOR). Additionally, they can be utilized for advanced non-arithmetic DNA logic devices like a parity generator (pG) and a parity checker (pC) for "error detection". Bit errors are an unavoidable and common occurrence during any computing. A cascade of XOR operations was used to evaluate these errors by introducing the pG and pC at the transmitting (TX) and receiving (RX) ends in binary transmission, respectively, which has devastating implications for reliable logic circuits, especially in advanced logic computation. Moreover, an even/odd natural number from 0 to 9 distinguishable pC was designed based on a dual-source responsive computing platform. This work offers inspiring avenues for a cost-effective strategy to construct highly-intelligent DNA computing devices by enhancing the multi-input responsive single DNA platform concept.

Construction of a scalable DNA computing nano-system for large-scale and complex logical operations.

The predictability of Watson-Crick base pairing provides unique structural programmability to DNA, facilitating the development and application of biomolecules in biocomputing. However, in DNA-based biocomputing, the scale of operation that can be achieved by an existing reaction system is very limited. How to expand the operation range of a logic circuit and realize the integration and extensibility of circuits is always the key problem to be solved in this field. In this work, by designing a multifunctional DNA-nanostructure-based reaction platform, which can realize an output of up to 2n scalable fluorescence signals, combined with the construction of an input "library" and a modular distribution strategy of output signals, for the first time, we successfully performed the calculation of both square roots and cube roots of consecutive integers within a decimal number of "10" and in each result of the operation, two digits after the decimal point are preserved (). We believe that the design concept presented in this work can help effectively solve the urgent problems of biological computing in terms of computational scaling, integration and scalability, and can open up new horizons for the design of new functional devices and complex computing circuits.

Discriminative Transition Sequences of Origami Metamaterials for Mechanologic

Transitions of multistability in materials are exploited for various functions and applications, such as spectral gap tuning, impact energy trapping, and wave steering. However, a fundamental and comprehensive understanding of the transitions, either quasistatic or dynamic transitions, has not yet been acquired, especially in terms of the sequence predictability and tailoring mechanisms. This research, utilizing the stacked Miura‐ori‐variant (SMOV) structure that has multistable shape reconfigurability as a platform, uncovers the deep knowledge of quasistatic and dynamic transitions and proposes the corresponding versatile formation and tuning of mechanical logic gates. Through theoretical, numerical, and experimental means, discriminative and deterministic quasistatic transition sequences, including reversible and irreversible ones, are uncovered, where they constitute a transition map that is editable upon adjusting the design parameters. Via applying dynamic excitations and tailoring the excitation conditions, reversible transitions between all stable configurations become attainable, generating a fully connected transition map. Benefiting from the nonlinearity of the quasistatic and dynamic transitions, basic and compound mechanical logic gates are achieved. The versatility of the scheme is demonstrated using a single SMOV to realize different complex logic operations without increasing structural complexity, showing its unique computing power and inspiring the avenue for efficient physical intelligence.

The thermal spin molecular logic gates modulated by light

Digital electronics and spintronics are based on logic operations. Here, nonequilibrium Green’s functions are incorporated with the density functional theory to evaluate the thermal spin transportation features of the photochromic molecule spintronic devices constructed by dihydropyrene/cyclophanediene (DDP/CPD) molecule in alone, series, or parallel, connected with graphene nanoribbons electrodes. Based on calculations, the spin-polarized currents can be manipulated by light. Then, a complete set of thermal spin molecular logic gates is proposed, including AND, OR, and NOT gates. The above logic gates can be employed to perform complex thermal spin molecular logic operations and facilitate all-optical control of thermal spin molecular devices.

Blockchain-Based Internet of Things Access Control Technology in Intelligent Manufacturing

The integration of information systems and physical systems is the development trend of today’s manufacturing industry. Intelligent manufacturing is a new model of manufacturing, based on advanced manufacturing technology with human–machine–material collaboration. Internet of Things technology is the core technology of intelligent manufacturing, and access control technology is one of the main measures to ensure the security of the IoT. In view of the problem that the existing IoT access control model does not support distributed and fine-grained dynamic access control, this paper uses the characteristics of blockchain, such as decentralization and non-tampering, combined with the attribute-based access control (ABAC) method, to propose a distributed access control method, applicable to the IoT environment in the process of intelligent manufacturing. This paper describes a fine-grained access control policy by defining the access control attribute values in a formal language, which supports complex logic operations in the policy and enhances the expressiveness of the model. Distributed access control decision making, using smart contracts for blockchain, improves the decision-making efficiency of the access control model, increases the post-facto audit of the access control behavior, and improves the overall security of IoT data protection. The paper concludes with proof of security and a performance analysis, and the experimental results, such as storage and computing overheads, show that this method can provide fine-grained, dynamic, and distributed access control for devices in intelligent manufacturing, ensuring the security and reliability of access control for IoT devices.

Construction of Multiple Logic Circuits Based on Allosteric DNAzymes.

In DNA computing, the implementation of complex and stable logic operations in a universal system is a critical challenge. It is necessary to develop a system with complex logic functions based on a simple mechanism. Here, the strategy to control the secondary structure of assembled DNAzymes’ conserved domain is adopted to regulate the activity of DNAzymes and avoid the generation of four-way junctions, and makes it possible to implement basic logic gates and their cascade circuits in the same system. In addition, the purpose of threshold control achieved by the allosteric secondary structure implements a three-input DNA voter with one-vote veto function. The scalability of the system can be remarkably improved by adjusting the threshold to implement a DNA voter with 2n + 1 inputs. The proposed strategy provides a feasible idea for constructing more complex DNA circuits and a highly integrated computing system.

Inverse design of ultra-compact photonic gates for all-optical logic operations

Logic gates have great importance in realization of rapid data transmission as well as low loss transfers. In this paper, a multi-objective inverse-design approach is implemented by using objective-first algorithm to design optical AND, OR, NAND and NOT logic gates on Si-platform at the design wavelength of 1.30 μm. For all gates, the design area is fixed to 2.24 μm × 2.24 μm. The optical logic ‘1’ output is accepted to be optical power values greater than 0.8 times of the input optical power. By implementing a Bias waveguide as well as two input ports, we made it possible to achieve logic ‘1’ output for logic operations having no inputs such as ‘0 NAND 0 = 1’ and ‘0 NOT = 1’. We binarized the proposed logic gates, and then numerically analyzed them by using finite-difference time-domain method. Proposed AND gate yields 1.20 times of input power for ‘1 AND 1 = 1’ logic operation and highest logic ‘0’ is obtained for logic operation of ‘1 AND 0 = 0’ as 0.40 times of the input power at the operating wavelength. It is also observed that proposed logic gates can operate not only at the design wavelength of 1.30 μm but also at broad wavelength regions as well. Finally, we demonstrate that it is possible to carry out complex logic operations by combining the proposed logic AND, OR and NAND gates to construct an XOR gate in the same platform.

Peptide-Based Sensing, Logic Computing, and Information Security on the Antimonene Platform.

Peptides have higher information density than DNA and equivalent molecular recognition ability and durability. However, there are currently no reports on the comprehensive use of peptides' recognition ability and structural diversity for sensing, logic computing, information coding, and protection. Herein, we, for the first time, demonstrate peptide-based sensing, logic computing, and information security on the antimonene platform. The molecular recognition capability and structural diversity (amino acid sequence) of peptides (Pb2+-binding peptide DHHTQQHD as a model) adsorbed on the antimonene universal fluorescence quenching platform were comprehensively utilized to sense targets (Pb2+) and give a response (fluorescence turn-on) and then to encode, encrypt, and hide information. Fluorescently labeled peptides used as the recognition probe and the information carrier were quenched and hidden by the large-plane two-dimensional material antimonene and specifically bound by Pb2+ as the stego key, resulting in fluorescence recovery. The above interaction and signal change can be considered as a peptide-based sensing and steganographic process to further implement quantitative detection of Pb2+, complex logic operation, information coding, encrypting, and hiding using a peptide sequence and the binary conversion of its selectivity. This research provides a basic paradigm for the construction of a molecular sensing and informatization platform and will inspire the development of biopolymer-based molecular information technology (processing, communication, control, security).

Ultrafast and Ultralow‐Power Voltage‐Dominated Magnetic Logic

To solve the von Neumann performance bottleneck, many kinds of magnetic logic devices are proposed. However, the operation speed, power consumption, and error rate of these devices are incompatible with complementary metal−oxide−semiconductor (CMOS) logic, and moreover, cascading of the devices is difficult. Herein, instead, a new voltage‐dominated magnetic logic‐memory device is proposed, with switching time of 300 ps and power consumption of 150 fJ, representing ≈10 times improvement compared with CMOS logic on the same scale. The device has a reliable output ratio of >3000%, a low working magnetic field of <10 mT, and a low error rate of ≈10−7. Moreover, complex logic operations, such as XOR gates and a full adder, can be realized using this device via cascading. As a result of these advantages, the magnetic logic‐memory device is well suited for practical applications.

Stacked Two-Dimensional MXene Composites for an Energy-Efficient Memory and Digital Comparator.

Two-dimensional MXene has enormous potential for application in industry and academia owing to its surface hydrophilicity and excellent electrochemical properties. However, the application of MXene in optoelectronic memory and logical computing is still facing challenges. In this study, an optoelectronic resistive random access memory (RRAM) based on silver nanoparticles (Ag NPs)@MXene-TiO2 nanosheets (AMT) was prepared through a low-cost and facile hydrothermal oxidation process. The fabricated device exhibited a typical bipolar switching behavior and controllable SET voltage. Furthermore, we successfully demonstrated a 4-bit in-memory digital comparator with AMT RRAMs, which can replace five logic gates in a traditional approach. The AMT-based digital comparator may open the door for future integrated functions and applications in optoelectronic data storage and simplify the complex logic operations.

Wide-spectrum photodetector constructed on a centimeter-scale flexible SnSe2 film using a new one-step strategy

Two-dimensional (2D) materials attached with flexible substrates enable possibilities to apply their superior properties to the rapidly increasing demand for foldable displays and wearable biosensors in the internet-of-things technology. However, previous two-step strategy to construct the flexible devices, namely first obtaining 2D materials elsewhere and then transferring them onto flexible substrates, can cause huge problems, including irreversibly undermining the device performance and limiting the material size. Here we propose a new one-step strategy (other than the liquid phase processing and low temperature synthesis methods), namely directly depositing appropriate 2D materials onto flexible substrates, which involves no transferring and can maintain the crystal quality and properties to the greatest extent. More importantly, this strategy in principle has no limit in the film size, hence removing a main obstacle for the practical use of flexible films, such as complex logic operations and large-area optoelectronic applications. Using this strategy, a centimeter-scale SnSe2 film is directly grown on polydimethylsiloxane, which is characterized as a uniform, out-of-plane oriented and semiconducting film that is robust to deformations. Based on the film, a flexible photodetector is fabricated and distinct photoresponse to a broad spectrum of light (405–830 nm) is observed, with remarkable technical parameters.

Character Beliefs in Story Generation

Character beliefs play a central role in many narratives, but are often not represented in planning-based author-centered narrative generation systems, or only represented in an ad hoc way. In this paper we will discuss how actions in Dynamic Epistemic Logic that affect the story world as well as the characters' beliefs, can be used in the context of narrative generation. By using this logical foundation we can ensure that the actors' beliefs are maintained in a logically consistent way, but we will also discuss how our system supports writing these complex logical operations in a concise way. We will also show how our system, which has limited planning capabilities, can come up with simple stories that cause characters to have beliefs desired by the author, and how our approach can be integrated with other work in the field.

The stepwise photochromic reactivity of diarylethene tuned by selective ions and fabrication of a molecular logic circuit

The tunable photochromic systems have received wide attention in the photoelectronic fields. Herein, we report a diarylethene derivative attached with 2-hydrazylbenzothiazole via Schiff base, which shows the typical photochromic properties upon alternating irradiation with UV and visible light. Remarkably, the varying binding mode and complex strength between the diarylethene and selective metal ions (Cu2+, Ni2+, Cr3+, Sn2+ and Al3+) enable the methanol solution of the diarylethene to exhibit stepwise photochromic reactivity by virtue of these metal ions. The photochromic reactivity of the diarylethene could be suppressed at different levels by the formation of the complex with Cu2+ and Ni2+ in a 2:1 binding mode, respectively, whereas the photochromic reactivity was enhanced to varying degrees by Cr3+, Sn2+ and Al3+ in a 1:1 binding mode. Based on these multiple stimuli responses, a logic circuit with six input signals and three output signals was constructed to perform complex logical operations at the single molecular level.

Developing an algorithm to minimize boolean functions for the visual-matrix form of the analytical method

This research has established the possibility of improving the effectiveness of the visual-matrix form of the analytical Boolean function minimization method by identifying reserves in a more complex algorithm for the operations of logical absorption and super-gluing the variables in terms of logical functions. An improvement in the efficiency of the Boolean function minimization procedure was also established, due to selecting, according to the predefined criteria, the optimal stack of logical operations for the first and second binary matrices of Boolean functions. When combining a sequence of logical operations using different techniques for gluing variables such as simple gluing and super-gluing, there are a small number of cases when function minimization is more effective if an operation of simply gluing the variables is first applied to the first matrix. Thus, a short analysis is required for the primary application of operations in the first binary matrix. That ensures the proper minimization efficiency regarding the earlier unaccounted-for variants for simplifying the Boolean functions by the visual-matrix form of the analytical method. For a series of cases, the choice of the optimal stack is also necessary for the second binary matrix. The experimental study has confirmed that the visual-matrix form of the analytical method, whose special feature is the use of 2-(n, b)-design and 2-(n, x/b)-design systems in the first matrix, improves the process efficiency, as well as the reliability of the result of Boolean function minimization. This simplifies the procedure of searching for a minimal function. Compared to analogs, that makes it possible to improve the productivity of the Boolean function minimization process by 100‒200 %. There is reason to assert the possibility of improving the efficiency of the Boolean function minimization process by the visual-matrix form of the analytical method, through the use of more complex logical operations of absorbing and super-gluing the variables. Also, by optimally combining the sequence of logical operations of super-gluing the variables and simply gluing the variables, based on the selection, according to the established criteria, of the stack of logical operations in the first binary matrix of the assigned function

Bistability-based foldable origami mechanical logic gates

Mechanical logic gates, counterparts of electronic logic gates, are highly desirable for the development of mechanical computing and robotic materials. Kirigami and origami based mechanical metamaterials have been shown to have attractive scale-free properties, e.g., multi-stability and programmability. Here, a bistability-based foldable waterbomb origami consisting of bistable kirigami units is proposed. The geometrical parameters dependence of the responses of the kirigami units and the origami is explored. Simplified models are developed, verified by numerical simulations and experiments. Based on the proposed origami, mechanical logic gates AND, OR, and NOT are designed and are experimentally demonstrated. The obtained results illustrate a possible solution for more complex logic operations (e.g., signal processing and data storage) from a mechanical deformation point of view by combining the logic gates together in a desired manner.