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    БВРУКВУРА И Π­Π›Π•ΠšΠ’Π ΠžΠΠΠ«Π• Π‘Π’ΠžΠ˜Μ†Π‘Π’Π’Π Π”Π•Π€Π•ΠšΠ’ΠžΠ’ НА Π“Π ΠΠΠ˜Π¦Π• Π‘ΠžΠ•Π”Π˜ΠΠ•ΠΠΠ«Π₯ ΠŸΠ›ΠΠ‘Π’Π˜Π ΠšΠ Π•ΠœΠΠ˜Π―

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    Comprehensive studies of the structure and electronic properties of defects occurring on the connection boundary of disarranged nβˆ’type Si(001) wafers have been made by the methods of transmission electron microscopy, deep level transient spectroscopy (DLTS) and photoluminescence. The main revealed defects are two types of dislocation structure: orthogonal dislocation network composed of two screw dislocation families and zigzag mixed dislocations. The dislocation structures observed are sources of intense luminescence whose spectra are appreciably different from the standard dislocation luminescence spectra at all the investigated misfit angles of the Si bonded wafers. We show that an increase of the misfit angle results in a strong transformation of the dislocation luminescence spectra consisting in changes of the form of the spectra and a decrease in the integral luminescence intensity. In the samples in question the DLTS method revealed the presence of deep centers the concentration of which increased with increasing of twist misorientation of bonded wafers. It has been established that the deep centers are related to the dislocation structures observed by means of transmission electron microscopy.Β ΠœΠ΅Ρ‚ΠΎΠ΄Π°ΠΌΠΈ ΠΏΡ€ΠΎΡΠ²Π΅Ρ‡ΠΈΠ²Π°ΡŽΡ‰Π΅ΠΈΜ† элСктрон- Π½ΠΎΠΈΜ† микроскопии, нСстационарной спСктроскопии Π³Π»ΡƒΠ±ΠΎΠΊΠΈΡ… ΡƒΡ€ΠΎΠ²Π½Π΅ΠΈΜ† ΠΈ Ρ„ΠΎΡ‚ΠΎΠ»ΡŽΠΌΠΈΠ½Π΅ΡΡ†Π΅Π½Ρ†ΠΈΠΈ ΠΏΡ€ΠΎΠ²Π΅Π΄Π΅Π½ΠΎ ΠΊΠΎΠΌ- плСксноС исслСдованиС структуры ΠΈ элСктронных свойств Π΄Π΅Ρ„Π΅ΠΊΡ‚ΠΎΠ², Π²ΠΎΠ·- Π½ΠΈΠΊΠ°ΡŽΡ‰ΠΈΡ… Π½Π° Π³Ρ€Π°Π½ΠΈΡ†Π΅ соСдинСния Ρ€Π°Π·ΠΎΡ€ΠΈΠ΅Π½Ρ‚ΠΈΡ€ΠΎΠ²Π°Π½Π½Ρ‹Ρ… пластин Si(001) nβˆ’Ρ‚ΠΈΠΏΠ° проводимости. УстановлСно, Ρ‡Ρ‚ΠΎ основными выявлСнными Π΄Π΅- Ρ„Π΅ΠΊΡ‚Π°ΠΌΠΈ ΡΠ²Π»ΡΡŽΡ‚ΡΡ дислокационныС структуры Π΄Π²ΡƒΡ… Π²ΠΈΠ΄ΠΎΠ²: ΠΎΡ€Ρ‚ΠΎΠ³ΠΎΠ½Π°Π»ΡŒΠ½Π°Ρ сСтка дислокаций, состоящая ΠΈΠ· Π΄Π²ΡƒΡ… сСмСйств Π²ΠΈΠ½Ρ‚ΠΎΠ²Ρ‹Ρ… дислокаций, ΠΈ Π·ΠΈΠ³Π·Π°Π³ΠΎΠΎΠ±Ρ€Π°Π·Π½Ρ‹Π΅ ΡΠΌΠ΅ΡˆΠ°Π½Π½Ρ‹Π΅ дис- Π»ΠΎΠΊΠ°Ρ†ΠΈΠΈ. ВыявлСно, Ρ‡Ρ‚ΠΎ Π½Π°Π±Π»ΡŽΠ΄Π°Π΅ΠΌΡ‹Π΅ дислокационныС структуры ΡΠ²Π»ΡΡŽΡ‚ΡΡ источником интСнсивной люминСс- Ρ†Π΅Π½Ρ†ΠΈΠΈ, спСктр ΠΊΠΎΡ‚ΠΎΡ€ΠΎΠΈΜ† Π·Π½Π°Ρ‡ΠΈΡ‚Π΅Π»ΡŒΠ½ΠΎ отличаСтся ΠΎΡ‚ стандартного спСктра дислокационной Π»ΡŽΠΌΠΈΠ½Π΅ΡΡ†Π΅Π½Ρ†ΠΈΠΈ ΠΏΡ€ΠΈ всСх исслСдуСмых ΡƒΠ³Π»Π°Ρ… ΠΏΠΎΠ²ΠΎΡ€ΠΎΡ‚Π½ΠΎΠΈΜ† Ρ€Π°Π·ΠΎΡ€ΠΈΠ΅Π½Ρ‚Π°Ρ†ΠΈΠΈ пластин Si. Показано, Ρ‡Ρ‚ΠΎ ΠΏΡ€ΠΈ ΡƒΠ²Π΅Π»ΠΈΡ‡Π΅Π½ΠΈΠΈ ΡƒΠ³Π»Π° Ρ€Π°Π·ΠΎΡ€ΠΈΠ΅Π½- Ρ‚Π°Ρ†ΠΈΠΈ происходит сильная транс- формация спСктров дислокационной Π»ΡŽΠΌΠΈΠ½Π΅ΡΡ†Π΅Π½Ρ†ΠΈΠΈ, которая Π·Π°ΠΊΠ»ΡŽΡ‡Π°Π΅Ρ‚ΡΡ Π² ΠΈΠ·ΠΌΠ΅Π½Π΅Π½ΠΈΠΈ Ρ„ΠΎΡ€ΠΌΡ‹ спСктров ΠΈ ΡƒΠΌΠ΅Π½ΡŒ- шСнии ΠΈΠ½Ρ‚Π΅Π³Ρ€Π°Π»ΡŒΠ½ΠΎΠΈΜ† интСнсивности Π»ΡŽΠΌΠΈΠ½Π΅ΡΡ†Π΅Π½Ρ†ΠΈΠΈ. ΠœΠ΅Ρ‚ΠΎΠ΄ΠΎΠΌ нСстацио- Π½Π°Ρ€Π½ΠΎΠΈΜ† спСктроскопии Π³Π»ΡƒΠ±ΠΎΠΊΠΈΡ… ΡƒΡ€ΠΎΠ²- Π½Π΅ΠΈΜ† Π² исслСдуСмых ΠΎΠ±Ρ€Π°Π·Ρ†Π°Ρ… выявлСно Π½Π°Π»ΠΈΡ‡ΠΈΠ΅ Π³Π»ΡƒΠ±ΠΎΠΊΠΈΡ… Ρ†Π΅Π½Ρ‚Ρ€ΠΎΠ², ΠΊΠΎΠ½Ρ†Π΅Π½Ρ‚Ρ€Π°- ция ΠΊΠΎΡ‚ΠΎΡ€Ρ‹Ρ… возрастаСт с ΡƒΠ²Π΅Π»ΠΈΡ‡Π΅Π½ΠΈΠ΅ΠΌ ΡƒΠ³Π»Π° Ρ€Π°Π·ΠΎΡ€ΠΈΠ΅Π½Ρ‚Π°Ρ†ΠΈΠΈ пластин. Уста- Π½ΠΎΠ²Π»Π΅Π½ΠΎ, Ρ‡Ρ‚ΠΎ ΠΎΠ±Π½Π°Ρ€ΡƒΠΆΠ΅Π½Π½Ρ‹Π΅ Π³Π»ΡƒΠ±ΠΎΠΊΠΈΠ΅ Ρ†Π΅Π½Ρ‚Ρ€Ρ‹ связаны с Π½Π°Π±Π»ΡŽΠ΄Π°Π΅ΠΌΡ‹ΠΌΠΈ ΠΌΠ΅Ρ‚ΠΎΠ΄ΠΎΠΌ ΠΏΡ€ΠΎΡΠ²Π΅Ρ‡ΠΈΠ²Π°ΡŽΡ‰Π΅ΠΈΜ† элСктрон- Π½ΠΎΠΈΜ† микроскопии дислокационными структурами.

    ChemInform Abstract: Cyclodextrins

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    Metallocavitins as Advanced Enzyme Mimics and Promising Chemical Catalysts

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    The supramolecular approach is becoming increasingly dominant in biomimetics and chemical catalysis due to the expansion of the enzyme active center idea, which now includes binding cavities (hydrophobic pockets), channels and canals for transporting substrates and products. For a long time, the mimetic strategy was mainly focused on the first coordination sphere of the metal ion. Understanding that a highly organized cavity-like enzymatic pocket plays a key role in the sophisticated functionality of enzymes and that the activity and selectivity of natural metalloenzymes are due to the effects of the second coordination sphere, created by the protein framework, opens up new perspectives in biomimetic chemistry and catalysis. There are two main goals of mimicking enzymatic catalysis: (1) scientific curiosity to gain insight into the mysterious nature of enzymes, and (2) practical tasks of mankind: to learn from nature and adopt from its many years of evolutionary experience. Understanding the chemistry within the enzyme nanocavity (confinement effect) requires the use of relatively simple model systems. The performance of the transition metal catalyst increases due to its retention in molecular nanocontainers (cavitins). Given the greater potential of chemical synthesis, it is hoped that these promising bioinspired catalysts will achieve catalytic efficiency and selectivity comparable to and even superior to the creations of nature. Now it is obvious that the cavity structure of molecular nanocontainers and the real possibility of modifying their cavities provide unlimited possibilities for simulating the active centers of metalloenzymes. This review will focus on how chemical reactivity is controlled in a well-defined cavitin nanospace. The author also intends to discuss advanced metal–cavitin catalysts related to the study of the main stages of artificial photosynthesis, including energy transfer and storage, water oxidation and proton reduction, as well as highlight the current challenges of activating small molecules, such as H2O, CO2, N2, O2, H2, and CH4

    Hydrophobic association of Fe(III) protoporphyrin IX with cyclodextrins and their derivatives

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