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Logic Gates (logic + gate)

Distribution by Scientific Domains

Chemistry	68%
Engineering	20%

Distribution within Chemistry

General & Introductory Chemistry	52%
Organic Chemistry	11%

Kinds of Logic Gates

molecular logic gate

Terms modified by Logic Gates

logic gate operations

Selected Abstracts

A Simple Fluorescent Ion-Pair Binding Host that Acts as an "If-Then" Logic Gate

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 26 2009
Sara Jane Dickson
Abstract A donor-acceptor-type carbazole pyridine derivative behaves as an "if-then" fluorescent molecular logic gate using chemical inputs in the form of copper(II) cations and nitrate anions. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]

A Bifunctional Chromogenic Calix[4]arene Chemosensor for Both Cations and Anions: A Potential Ca2+ and F, Switched INHIBIT Logic Gate with a YES Logic Function

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 24 2010
Kai-Chi Chang
Abstract A bifunctional chromogenic calix[4]arene 3, which contains both triazoles and hydroxy azophenols as both cationic and anionic recognition sites and the azophenol moiety as a coloration unit, was designed and synthesized. The recognition of Ca2+ by 3 gave rise to a marked colour change from greenish to bright yellow, whereas the recognition of F, by 3 showed a colour change from light green to bluish. The colour changes of 3 by the inputs of Ca2+ and F, have been implemented to construct a combinational logic circuit at the molecular level. [source]

An Electrochemically Transduced XOR Logic Gate at the Molecular Level,

ANGEWANDTE CHEMIE, Issue 14 2010
Yaqing Liu Dr.
Goldene Logik: Die Vereinigung von kathodischen und anodischen elektrochemischen Stromgleichrichtern auf einer Goldelektrode (siehe Bild) resultierte in einem molekularen XOR-Logikgatter mit hohem Wechselverhältnis zwischen den elektrischen Ausgabesignalen ,1" und ,0". Wenn die Elektrode mit dem Redoxvermittler Ferrocen modifiziert wird, können sukzessive XOR-Logikgatter-Funktionen ausgeführt werden, ohne dass das System zurückgesetzt werden muss. [source]

Colorimetric Logic Gates Based on Supramolecular DNAzyme Structures,

ANGEWANDTE CHEMIE, Issue 26 2010
Sai Bi Dr.
Logisch! Eine Serie DNAzym-basierter supramolekularer Strukturen bildet die Grundlage für einen Satz der booleschen Algebra folgender Gatter (siehe Bild). Als Eingabe fungieren zwei Metall-Ionen (Mg2+ und Pb2+), und die Ausgabe zeigen in einem kolorimetrischen Verfahren Gold-Nanopartikel(AuNP)/DNA-Sonden an. Bei Raumtemperatur wurde eine gute Effizienz dieses Systems erreicht. [source]

Molecular Logic Gates Connected through DNA Four-Way Junctions,

ANGEWANDTE CHEMIE, Issue 26 2010
Alex Lake
Logisch, oder? In verknüpfbaren molekularen Logikgattern aus DNA werden die Oligonucleotid-Eingangs- und -Ausgabesignale von einem Gatter zum anderen weitergegeben, indem Komplexe gebildet werden. Bei starken Signalen entstehen DNA-Kreuzungen, bei schwachen Signalen lösen sie sich auf. [source]

Dual-Mode Switching in Highly Fluorescent Organogels: Binary Logic Gates with Optical/Thermal Inputs,

ANGEWANDTE CHEMIE, Issue 38 2009
Won Chung
Eine An/Aus-Beziehung: Ein supramolekulares binäres ,OR"-Logikgatter, das eine hochverstärkte Fluoreszenzemission als Ausgabesignal erzeugt, wird vorgestellt (siehe Bild). Das System besteht aus einem Organogelbildner und einer photochromen Verbindung und verarbeitet zwei Eingabekanäle aus UV-Strahlung und thermischem Erwärmen. [source]

ChemInform Abstract: Novel Pyrene-Armed Calix[4]arenes Through Triazole Connection: Ratiometric Fluorescent Chemosensor for Zn2+ and Promising Structure for Integrated Logic Gates.

CHEMINFORM, Issue 49 2008
Lin-Na Zhu
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Multivalued and Reversible Logic Gates Implemented with Metallic Nanoparticles and Organic Ligands

CHEMPHYSCHEM, Issue 8 2010
Javier Cervera Dr.
It makes perfect sense: Binary and multivalued XOR gates based on metal nanoparticles linked to electrodes by organic ligands are described. The logic scheme makes use of the Coulomb blockade in the metallic nanoparticles and the electron tunneling in the organic ligands. A reversible logic Feynman gate (see picture) can also be implemented. [source]

Novel Pyrene-armed Calix[4]arenes through Triazole Connection: Ratiometric Fluorescent Chemosensor for Zn2+ and Promising Structure for Integrated Logic Gates

CHINESE JOURNAL OF CHEMISTRY, Issue 8 2008
Lin-Na ZHU
Abstract Two novel pyrene-armed calix[4]arenes by triazole connection were synthesized using "click" chemistry. Compound 1 with two pyrene subunits appended to the lower rims of the calix[4]arene shows ratiometric fluorescence response toward Zn2+, and selective fluorescence quenching toward heavy metal ions such as Cu2+, Hg2+ and Pb2+; while compound 2 with one pyrene subunit exhibits significant fluorescence quenching toward Cu2+ and moderate quenching behaviour toward Hg2+. By utilizing the different fluorescence behavior of 1 toward Zn2+ and Cu2+, inhibition (INH) and not or (NOR) logic gates were established. [source]

A Simple Fluorescent Ion-Pair Binding Host that Acts as an "If-Then" Logic Gate

Nanoscale Single-Crystal Circuits: Assembly of Nanoscale Organic Single-Crystal Cross-Wire Circuits (Adv. Mater.

ADVANCED MATERIALS, Issue 42 2009
42/2009)
Organic single-crystal circuits with versatile functions, such as inverters, NOR, and NAND gate, can be assembled by nanomechanical manipulation of nanowires of CuPc, F16CuPc and SnO2:Sb, report Thomas Bjornholm, Wenping Hu, and co-workers on p. 4234. The circuits show ultralow power consumption (40 pW per logic gate) and high voltage gain. In combination with generic "bottom-up" assembly methods developed for nanowires, this opens new opportunities in organic nanoelectronics and for highly sophisiticated integrated logic circuits [source]

The use of not logic in fault tree analysis

QUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 3 2001
J. D. Andrews
Abstract Risk and safety assessments carried out on potentially hazardous industrial systems commonly employ fault tree analysis to predict the probability or frequency of system failure. Causes of the system failure mode are developed in an inverted tree structure where the events are linked using logic gates. The type of logic is usually restricted to AND and OR gates which makes the fault tree structure coherent. The use, directly or indirectly, of the NOT logic gate is generally discouraged as this can result in a non-coherent structure. Non-coherent structures mean that components' working states contribute to the failure of the system. The qualitative and quantitative analysis of such fault trees can present additional difficulties when compared to the coherent versions. This paper examines some of the difficulties that can occur, and what potential benefits can be derived from the incorporation of NOT logic. It is shown that the binary decision diagram (BDD) method can overcome some of the difficulties in the analysis of non-coherent fault trees. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Molecular Logic Operations Based on Surfactant Nanoaggregates,

CHEMPHYSCHEM, Issue 13 2008
Junhong Qian Dr.
Abstract Two molecular logic gates, FS1 and FS2, which display a UV and fluorescence behavior that is dependent on the pH value and the sodium dodecyl sulfate (SDS) surfactant concentration, are demonstrated based on the intramolecular charge-transfer mechanism. They are constructed according to the inorganic salts that induce transformation from premicelle to micelle. The absorption band of FS1 at 480 nm is significantly enhanced only when both SDS and Na2SO4 are the input at high concentrations, in accordance with an AND logic gate. The OR logic function can be realized in a 3.5,mM SDS/FS2 aqueous solution with SDS and Na2SO4 as inputs along with the emission intensity as output. Furthermore, half addition and half subtraction can be incorporated in FS1. This is facilitated by the surfactant, due to its versatility. [source]

Assembly of Nanoscale Organic Single-Crystal Cross-Wire Circuits

ADVANCED MATERIALS, Issue 42 2009
Qingxin Tang
Organic single-crystal transistors and circuits can be assembled by nanomechanical manipulation of nanowires of CuPc, F16CuPc, and SnO2:Sb. The crossed bar devices have low operational voltage, high mobility and are stable in air. They can be combined into circuits, providing varied functions including inverters and NOR and NAND logic gates, opening new opportunities for organic nanoelectronics and highly sophisticated integrated logic devices. [source]

Circuits, computers, and beyond Boolean logic,

INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 5-6 2007
Tamás Roska
Abstract Historically, the invention of the stored programmable computer architecture, introduced by John Von Neumann, was also influenced by electrical circuit implementation aspects, as well as tied to fundamental insight of logic reasoning. It can also be considered as a mind-inspired machine. Since then, the implementation of logic gates, control and memories has developed independently of the architecture. The Cellular Wave Computer architecture (IEEE Trans. Circuits Syst. II 1993; 40:163,173; Electron. Lett. 2007; 43:427,449; J. Circuits Syst. Comput. 2003; 5(2):539,562) as a spatial,temporal universal machine on flows has also been influenced by circuit aspects of very large-scale integration (VLSI) technology, as well as some motivating living neural circuits, via the cellular nonlinear (neural) network (CNN). It might be considered as a brain-inspired machine. In this paper, after summarizing the main properties of the Cellular Wave Computer, we highlight a few basic properties of this new kind of computer and computing. In particular, phenomena related to (i) the one-pass solution of a set of implicit equations due to real-time spatial array feedback, (ii) the true random signal array generation via the insertion of the continuous physical noise signals, (iii) the finite synchrony radius due to the functional delay of wires, as well as to (iv) biology relevance. We also show that the Cellular Wave Computer is performing spatial,temporal inference that goes beyond Boolean logic, a characteristic of living neural circuits. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Power-delay optimization of D-latch/MUX source coupled logic gates

INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 1 2005
M. Alioto
In this paper a design strategy for MUX, XOR and D-latch source coupled logic (SCL) gates is proposed. To this end, an analytical model of the delay and the noise margin as a function of the transistors' aspect ratio and bias current is first introduced. Successively, analytical equations of the transistors' aspect ratio to meet a given noise margin specification are derived as a function of the bias current, and are then used along with the delay model to express the delay as an explicit function of the bias current and noise margin. The simplified delay expression explicitly relates speed performance to power dissipation and the noise margin, thereby providing the designer with the required understanding of the trade-offs involved in the design. Therefore, the criteria proposed allow the designer to consciously manage the power-delay trade-off. The delay dependence on the logic swing is also investigated with results showing that this delay is not necessarily reduced by reducing the logic swing, in contrast with the usual assumption. Since the results obtained are valid for all SCL gates and are independent of the CMOS process used, the guidelines provided afford a deeper understanding of SCL gates from a design point of view. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Modelling of source-coupled logic gates

INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 4 2002
M. Alioto
Abstract In this paper, the modelling of CMOS SCL gates is addressed. The topology both with and without output buffer is treated, and the noise margin as well as propagation delay performance are analytically derived, using standard BSIM3v3 model parameters. The propagation delay model of a single SCL gate is based on proper linearization of the circuit and the assumption of a single-pole behaviour. To generalize the results obtained to cascaded gates, the effect of the input rise time and the loading effect of an SCL gate are discussed. The expressions obtained are simple enough to be used for pencil-and-paper evaluations and are helpful from the early design phases, as they relate SCL gates performance to design and process parameters, allowing the designer to gain an intuitive understanding of performance dependence on design parameters and technology. The model has been validated by comparison with extensive simulations using a 0.35-µm CMOS process. The model agrees well with the simulated results, since in realistic cases the difference is less than 20% both for noise margin and delay. Therefore, the model proposed can be profitably used for pencil-and-paper evaluations and for computer-based timing analysis of complex SCL circuits. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Crossbar assembly of antibody-functionalized peptide nanotubes via biomimetic molecular recognition,

JOURNAL OF PEPTIDE SCIENCE, Issue 2 2008
Linglu Yang
Abstract Previously, a large scale assembly of nanowires in a parallel array configuration has been demonstrated, and one type of nanowire could interconnect two electrodes in the high-wire density. However, to assemble nanowires into practical logic-gate configurations in integrated circuits, we need more than the parallel assembly of nanowires. For example, when the assembling nanowires are monopolar semiconductors, logic gates such as AND, OR and NOR are to be assembled necessarily from two types of semiconducting nanowires, n -type and p -type, and some of these nanowires must cross perpendicularly to form a crossbar geometry for the logical operation. In this paper, the crossbar assembly of antibody-functionalized peptide nanotubes was demonstrated by a new biomimetic bottom-up technique. Molecular recognition between antigens and antibodies enabled two types of the antibody-functionalized bionanotubes to place them onto targeted locations on substrates, where their complementary antigens were patterned. When two rectangular pads of antigens, human IgG and mouse IgG, were patterned perpendicularly on an Au substrate by nanolithography and then the antihuman IgG nanotubes and the antimouse IgG nanotubes were incubated on this substrate in solution, these bionanotubes were attached onto corresponding locations to form the crossbar configuration. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd. [source]

Molecular rectification in metal,bridge molecule,metal junctions

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 4 2010
Yaqing Liu
Abstract Molecular bridged nanocontacts allow direct electrical addressing of electroactive molecules, which is of interest for the development of molecular based electronic devices. In the present paper, the electroactive molecule 6-ferrocenyl-1-hexanethiol (Fc-HT) was integrated into metal,bridge,metal (MBM) junctions assembled in a scanning tunneling microscope (STM) setup. A diode-like behavior was observed from the current/bias (It/Vb) signal through Au (substrate)/Fc-HT/Au (tip) junction, which presented an asymmetric current response due to the resonant tunneling between metal electrode and ferrocenylthiol molecules. With gate electrode modulation, the enhancement of the tunneling current can be controlled, which allows to tune the direction of the current rectification. Our investigations demonstrated that ferrocenylthiol bridged MBM nanostructure has potential applications in the future design of higher-order heterojunctions components in combination with electrochemical logic gates. [source]

The use of not logic in fault tree analysis

All-Optical Integrated Logic Operations Based on Chemical Communication between Molecular Switches

CHEMISTRY - A EUROPEAN JOURNAL, Issue 1 2009
Serena Silvi Dr.
Abstract Molecular logic gates process physical or chemical "inputs" to generate "outputs" based on a set of logical operators. We report the design and operation of a chemical ensemble in solution that behaves as integrated AND, OR, and XNOR gates with optical input and output signals. The ensemble is composed of a reversible merocyanine-type photoacid and a ruthenium polypyridine complex that functions as a pH-controlled three-state luminescent switch. The light-triggered release of protons from the photoacid is used to control the state of the transition-metal complex. Therefore, the two molecular switching devices communicate with one another through the exchange of ionic signals. By means of such a double (optical,chemical,optical) signal-transduction mechanism, inputs of violet light modulate a luminescence output in the red/far-red region of the visible spectrum. Nondestructive reading is guaranteed because the green light used for excitation in the photoluminescence experiments does not affect the state of the gate. The reset is thermally driven and, thus, does not involve the addition of chemicals and accumulation of byproducts. Owing to its reversibility and stability, this molecular device can afford many cycles of digital operation. [source]

Squaraines as Reporter Units: Insights into their Photophysics, Protonation, and Metal-Ion Coordination Behaviour

CHEMISTRY - A EUROPEAN JOURNAL, Issue 32 2008

Abstract The synthesis, photophysical properties, protonation, and metal-ion coordination features of a family of nine aniline-based symmetrical squaraine derivatives are reported. The squaraine scaffold displays very attractive photophysical properties for a signalling unit. These dyes show absorption and weakly Stokes-shifted, mirror-image-shaped emission bands in the visible spectral range and there are no hints of multiple emission bands. The mono-exponential fluorescence decay kinetics observed for all the derivatives indicate that only one excited state is involved in the emission. These data stress the interpretation that squaraines can be regarded as polymethine-type dyes. From a coordination chemistry point of view, the squaraines possess four potential binding sites; that is, two nitrogen atoms from the anilino groups and two oxygen atoms from the central C4O2 four-membered ring. These coordination sites are part of a cross-conjugated ,-system and coordination events with protons or certain metal ions affect the electronic properties of the delocalised ,-system dramatically, resulting in a rich modulation of the colour of the squaraines. The absorption band at around 640,nm is blue-shifted when coordination at the anilino nitrogen atoms occurs, whereas coordination to the C2O4 oxygen atoms results in the development of red-shifted bands. Addition of more than one equivalent of protons or metal cations could additionally entail mixed N,O - or N,N -coordinated complexes, manifested in the development of a broad band at 480,nm or complete bleaching in the visible range, respectively. Analysis of the spectrophotometric titration data with HYPERQUAD yielded the macroscopic and microscopic stability constants of the complexes. Theoretical modelling of the various protonated species by molecular mechanics methods and consideration of some of the title dyes within the framework of molecular chemosensing and molecular-scale "logic gates" complement this contribution. [source]

Ion-Triggered Multistate Molecular Switching Device Based on Regioselective Coordination-Controlled Ion Binding

CHEMISTRY - A EUROPEAN JOURNAL, Issue 23 2005
Anne Petitjean Dr.
Abstract Molecular devices capable of accessing different controlled conformational states, while optically signaling the occupied state, are attractive tools for nanotechnology since they relate to both areas of molecular mechanical devices and logic gates. We report here a simple molecular system that allows access to four distinct conformational and optical states. It is based on the regioselective complexation of metal ions to a heterocyclic ligand triad, which is dictated by the accessible coordination geometry and electrostatic properties of two distinct binding subunits. Thus, local conformational switching is brought about by tetrahedral coordination (of CuI) or octahedral coordination (of M2+ ions) to bidentate and tridentate binding subunits, respectively. The shape modifications undergone represent an ion-controlled nanomechanical device. They give controlled access to four different states that display different physico-chemical (e.g. optical) properties and provide a basis for logic gate operations. [source]

Molecular Logic Operations Based on Surfactant Nanoaggregates,

Novel Pyrene-armed Calix[4]arenes through Triazole Connection: Ratiometric Fluorescent Chemosensor for Zn2+ and Promising Structure for Integrated Logic Gates