AND-logic gate

The immediate causes of the TOP event are shown in the fault tree with thek relationship to the TOP event. If any one of the immediate causes results dkecdy in the TOP event, the causes are connected to the TOP event with an OR logic gate. If all the immediate causes are requked for TOP event occurrence, then the causes are connected to the TOP event with an AND logic gate. Each of the immediate causes is then treated in the same manner as the TOP event, and its immediate, necessary, and sufficient causes are determined and shown on the fault tree with the appropriate logic gate. This development continues until all intermediate fault events have been developed into thek basic causes. 

The only ingredient in the proof of Life s universality that we have not yet discussed is memory storage. While a finite memory is fairly easy to implement with wires and logic gates - for example, glider-stream-encoded information can be made to circulate around a memory circuit contained within the computer - the construction of an arbitrarily large memory requires a bit more work,... 

Magri DC, Brown GJ, McClean GD, de Silva AP (2006) Communicating chemical congregation a molecular and logic gate with three chemical inputs as a lab-on-a-molecule prototype. J Am Chem Soc 128 4950-4951... 

Ami S, Hliwa M, Joachim C (2003) Molecular OR and AND logic gates integrated in a single molecule. Chem Phys Lett 367 662... 

Javey, A. et al. 2002. High-kappa dielectrics for advanced carbon-nanotube transistors and logic gates. Nature Mater. 1 241-246. 

AP. de Silva, H.QN. Gunaratne, C.P. McCoy, Molecular photoionic AND logic gates with bright fluorescence and off-on digital action , J. Am. Chem Soc 1997, 119, 7891-7892. 

For example, the AND logic gate has two inputs and one output. The truth table for the AND gate is shown in Table 12.4. 

Figure 9. (a) Schematic representation of the five-module format of a photoactive triad which is switchable only by the simultaneous presence of a pair of ions. This design involves the multiple application of the ideas in Figure 1. The four distinct situations are shown. Note that the presence of each guest ion in its selective receptor only suppresses that particular electron transfer path. The mutually exclusive selectivity of each receptor is symbolized by the different hole sizes. All electron transfer activity ceases when both guest ions have been received by the appropriate receptors. The case is an AND logic gate at the molecular scale. While this uses only two ionic inputs, the principle established here should be extensible to accommodate three inputs or more, (b) An example illustrating the principles of part (a) from an extension of the aminomethyl aromatic family. The case shown applies to the situation (iv) in part (a) where both receptors are occupied. It is only then that luminescence is switched "on". Protons and sodium ions are the relevant ionic inputs.

In this chapter, we will discuss the recent results regarding the development of molecular switches and logic gates toward information processing at the molecular level based on electroactive molecules and supramolecules. Also, we will illustrate the progress of application of electron donor-acceptor compounds in high-density information storage. 

Photoinduced electron transfer processes involving electron donor (D) and acceptor (A) components can be tuned via redox reactions. Namely, the excited-state properties of fluorophores can be manipulated by either oxidation of electron donors or reduction of electron acceptors. Also, the oxidized and the reduced species show different properties compared to the respective electron donors and acceptors. By making use of these properties of electron donors and acceptors, a number of molecular switches and logic gates have been described in recent years. In the following, we will introduce these redox-controlled molecular switches according to the redox centers. 

A Credi. Molecular-Level-Machines and Logic Gates. PhD thesis, Universita di Bologna, Italy, 1998. 

S. J. Zilker, C. Detcheverry, E. Cantatore, D. M. d. Leeuw, Bias stress in organic fhin-film transistors and logic gates, Appl. Phys. Lett. 2001, 79, 1124-1126. 

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