Wyniki wyszukiwania - BazTech

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Chemosensory porfirynowe. Oddziaływanie 2H-porfiryn z wybranymi akceptorami elektronowymi

Dyrda G., Słota R., Mele G.

Chemik

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2014

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Vol. 68, nr 4

396--401

PL

Zbadano możliwość zastosowania 5,10,15,20-tertrakis-[-4‒2-(3-pentadecylofenoksy)-etoksy]fenyloporfiryny, jako chemosensora akceptorów elektronów: HCl, TFA i BF3, w fazie stałej, w postaci cienkiej warstwy na nośniku szklanym oraz w fazie ciekłej w benzenie. W widmie UV-Vis chemosensora pod wpływem akceptora następują charakterystyczne zmiany w położeniu pasm, połączone ze zmianą barwy układów. Wskazuje to na dużą wrażliwość porfiryny na działanie badanych akceptorów.

EN

The possibility to use 5,10,15,20-tetrakis-[-4–2-(3-pentadecylphenoxy)-ethoxy]phenylporphyrin as a chemosensor for the detection of electron acceptors: HCl, TFA and BF3 in solid-phase in the form of thin film on glass carrier plate and in liquid phase in benzene. When chemosensor is under the influence of acceptor, the characteristic changes occur in the position of bands in its UV-VIS spectrum accompanied by the change of system colour. This indicates high sensitivity of porphyrin to action of studied acceptor systems.

2

ZnS Cu-doped quantum dots

Ziółczyk P., Miller E., Przybyt M.

Biotechnology and Food Science

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2014

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Vol. 78, nr 1

53--69

EN

The paper presents a survey of literature on the structure and optical properties of ZnS and copper ion-doped ZnS quantum dots. The effect of other metal dopants on the spectral properties of ZnS:Cu quantum dots was also considered. The influence of such parameters as dopant concentration, temperature of the synthesis and compounds which form or modify the additional layer on dots on spectral properties of the quantum dots was described. Examples of application of ZnS:Cu quantum dots are also given.

3

Molekularne bramki logiczne

Szaciłowski K.

Wiadomości Chemiczne

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2004

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[Z] 58, 1-2

11--45

EN

Rapid development of different electronic devices was initiated by the discovery of semiconductor-based switch - a transistor in 1948 by J. Bardeen, W.H. Brattain and W.B. Shockley. All electronic devices are based on semiconductor components ever since. Growing demand for bigger memorics and faster processors requires smaller and smaller transistors and other componcnts. Soon the integration scale of elcctronic components will reach the physical limits and further speeding up will not be possible. The only solution of the crisis is application of single molecules and molecular systems for data acquisition, storage, transfer and processing. There are numerous chemical systems capable of performing logical operations, some of them have already found practical applications. Carbon nanotubes, semiconductor nanocrystals (quantum dots), organic polymers and other supramolecular assemblies can be a basis for construction of chemical switches and logic gates. These devices, however, are chemical versions of traditional semiconductor devices, as the operational principles are imported directly from solid state electronics. This paper deals with several different approaches towards chemical computing. A large variety of other chemical systems can be used for computing purposes. Some of them are extremely complex (like Aviram-Ratner type devices) and require advanced organic syntheses, other are very simple, like organic dyes and simple transition metal cornplexes. Despite substantial difference in chemical structure, the reactivity of these systems can be described using common language: the Boolean logic. Any chemical system, which exists in at least two different forms of different optical or electrochemical properties and can be switched with some chemical or physical stimuli (light, redox potential, pH, specific substrate) can be treated as a molecular switch. If the logic structure of the switch is more complex (i.c. there are several different states or several switching stimuli) the system forms a logic gate. The principles of operation of chemical logic gates are identical with those of clectronic logic gates. The input and output signals may have only two values: 0 (OFF, FALSE) or 1 (ON, TRUE). Output signal is a Boolean function of input signals. The basic logic gates are: YES, NOT, OR, NOR, AND, NAND, EX-OR and EX-NOR. Even the simplest molecular system can exhibit complex logic behaviour, it depends mostly on specific chemical reactivity of the system, proper assignment of the input and output parametcrs and imagination of the experimenter. Some systems are complex enough to emulate not only single gates, but also much larger computing circuits of multilayer parallel architecture. At the same time these systems are closely related to quantum computers: they can be considered as supetposition of different logic gates. Although many of these systems are very impractical, they are guidelines leading to new powerful technologies.