Electret Materials Based on Fluoropolymers Modified with Vanadium- and Phosphorus-Containing Structures

Russian Journal of Applied Chemistry - Organo-inorganic composite materials based on films of polytetrafluoroethylene and tetrafluoroethylene–hexafluoropropylene copolymer, modified with...     

Photo- and thermochromic mannich bases. 1. Mannich bases from 3,5-di-tert-butyl-4-hydroxybenzaldehyde and 2-naphthols

Mannich bases exhibiting photo- and thermochromic properties in solutions were synthesized from 3,5-di-tert-butyl-4-hydroxybenzaldehyde and 2-naphthols. An investigation of an acetyl derivative of methylenequinone, modeling a product of photo- and thermochromic transformations, proved that the color change of solutions of the Mannich bases is due to reversible dissociation into colored methylenequinones and morpholine. On the basis of data of x-ray diffraction analysis of one of the Mannich bases, characteristics of their molecular structure were determined, and reasons were stated for their effect on the dissociation mechanism.     

Unusual synthesis,structure, and thermochromic properties of novel sterically hindered cyclohexadienes

Oxidation of 4-[-morpholino--(2-hydroxyphenyl)]methyl-2,6-di-(tert-butyl)-phenol (I) follows an unusual course, with formal loss of the benzyl carbon atom, to give 2,6-di(tert-butyl)-4-morpholino-4-(2-hydroxyphenyl)cyclohexa-2,5-dienone (II), which is thermochromic in solution. This property is due to the dissociation of (II) into morpholine and 3,5-di(tert-butyl)-2,4-diphenoxyquinone. The structure of (II) was established directly by x-ray diffraction, which enabled its conformational features to be related to its thermochromic properties. An x-ray examination of 3,3,5,5-tetra(tertbutyl)-2,4-diphenoquinone (X), together with the direct synthesis of the thermochromic analog of (II) (2,6-di(tert-butyl)-4-morpholino-4-[2-hydroxy-3,5-di(tert-butyl)phenyl]cyclohexa-2,5-dienone) (XI) from (X) and morpholine, confirmed the proposed mechanism of thermochromic dissociation.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1121–1129, May, 1991.The authors thank V. I. Minkin and A. S. Morkovnik for participating in discussions of this work.     

Geometry changes of a Cu(I) phenanthroline complex on photoexcitation in a confining medium by time-resolved X-ray diffraction

Using a stroboscopic technique, in which the molecule is repeatedly excited and the structural change is probed more than 5000 times per second immediately after excitation, we performed a 16 K time-resolved single-crystal study of the microsecond lifetime triplet state of the Cu(I)phenanthroline derivative[Cu(I)(dmp)(dppe)][PF6] (dppe = 1,2-bis(diphenylphosphino)ethane). The geometry changes on excitation differ for the two symmetry-independent molecules, but are in the same direction as calculated for an isolated reference molecule, although the flattening distortion in the crystal is significantly smaller, implying that the reorganization energy is greatly affected by the confining medium.     

Shedding light on the structure of a photoinduced transient excimer by time-resolved diffraction

Time-resolved single-crystal diffraction performed with synchrotron radiation shows that the 53(1) micros phosphorescent state, generated in the crystalline phase of trimeric {[3,5-(CF3)(2)Pyrazolate]Cu}(3) molecules by exposure to 355 nm of light at 17 K, is due to the formation of an excimer rather than the shortening of the intramolecular Cu...Cu distances within the trimeric units, or the formation of a continuous chain of interacting molecules. One of the intermolecular Cu...Cu distances contracts by 0.56 Angstroms from 4.018(1) to 3.46(1) Angstroms;, whereas the interplanar spacing of the trimers is reduced by 0.65 Angstroms; from 3.952(1) to 3.33(1) Angstroms. Density-functional theory calculations support the formation of a Cu...Cu bond through the intermetallic transfer of a Cu 3d electron to a molecular orbital with a large 4p contribution on the reacting Cu atoms.     

Nonstationary processes in a diffraction-output orotron

The nonlinear dynamics of an orotron with diffraction output is studied. The evolution of the longitudinal field distribution is described by means of a parabolic equation subject to the condition of zero reflection at the collector end of the interaction space. For stationary regimes, the regions of high efficiency are delineated on the parameter plane, with the parameters being the departure from the critical frequency and the reduced length of the interaction space. From numerical results, the parameter plane is divided into the regions of stationary operation, periodic self-modulation, and stochastic self-modulation. It is demonstrated that self-modulation oscillating modes can be obtained most easily if the effective bounce frequency slightly exceeds the cutoff frequency, with the former being the blinking frequency of the dipole comprising an electron and its reflection in the regularly corrugated slow-wave guide.     

Response of a gyrotron to small-amplitude low-frequency-modulated microwaves reflected from a plasma

Experiments in the L-2M stellarator revealed the intense noise modulation of the gyrotron power and the change in its mean value under the action of the noise modulation of radiation reflected from the plasma column. The effect observed is explained in terms of the resonant locking of the gyrotron self-oscillations due to wave reflection from the fluctuating plasma load.     

使用分子量级前躯体制备CuInSe_2及其合金并应应用用于光伏发电(英文)

黄铜矿铜铟硒化合物CuInSe2及其与硫或嫁的合金CuIn(Se,S)2或CuInGa(Se,S)2,即所说的CIGS,已通过20%的实验室规模器件光电转换效率展示了其地面光伏应用的巨大潜力。为了减少初始资金成本,提高材料利用率,科研工作者们已经尝试了许多努力通过非真空制程沉积CIGS。这些制程包括电镀工艺,基于颗粒(浆或纳米颗粒)的制程和基于分子量级前趋体的制程。原则上,分子量级前趋体可以使组分元素达到充分混合,可以最大程度地实现组份在基板不同区域的均一分布。这对于一个复杂的涉及到五个主要元素的化合物系统尤为重要。从这个角度来看,分子前趋体的方法具有大面积均匀沉积铜铟镓硒的巨大潜力。这篇综述将着重讨论使用分子前趋体沉积铜铟镓硒制程的最新发展。