Direct introduction of heterocyclic units into porphyrin derivatives

In the reaction with quinazoline and 5-phenyl-1,2,4-triazin-5(2H)-one, 5,10,15,20-tetra(4-methoxyphenyl)porphyrin exhibits nucleophilic properties. In quinazoline excess, C—C coupling occurs at the C=N bond of azines and position 3 of the aryl ring to form 5,10,15,20-tetrakis(3-heteryl-4-methoxyphenyl)porphyrins. Monoheteryl-substituted porphyrin was obtained by the reaction of equimolar amounts of 5,10,15,20-tetra(4-methoxyphenyl)porphyrin and 5-phenyl-1,2,4-triazin-5(2H)-one.     

Structural explanation of the spectral features of the nonsymmetrical complex {2,3,7,8,12,13,17,18‐octaethyl‐5‐[(methylimino)methyl]porphyrinato‐κ4N21,N22,N23,N24}palladium(II)

The features of porphyrins defining their functionality are related to their conformational flexibility. The degree of nonplanarity of metalloporphyrins depends directly on the number of substituents, their size and their location. The introduction of substituents in the meso positions of β‐substituted porphyrins increases the steric interaction and leads to distortions of the porphyrin core. Increasing the distortion of the porphyrin core would augment the bathochromic (red) shift of the electronic absorption spectra. A new nonsymmetrical 2,3,7,8,12,13,17,18‐octaethyl‐5‐[(methylimino)methyl]porphyrin complex of palladium(II), [Pd(C₃₈H₄₇N₅)], was synthesized and characterized by NMR, mass spectrometry and X‐ray analysis. The features of the electronic absorption spectrum of the synthesized complex are explained by the planarity of the porphyrin core and the π‐system of the imino group orthogonal to it.     

Synthesis of Symmetrical and Nonsymmetrical Bisthienylcyclopentenes

Diarylethenes possess unique structural properties, which enabled them to find widespread applications in the field of photochromism. Nowadays, bisthienylcyclopentenes (BTCs) present the most popular subfamily of these compounds, which are widely used as P‐type chromophores. This minireview summarises the main strategies for the synthesis of symmetrical and nonsymmetrical BTCs. In addition, attention is drawn to desymmetrisations achieved by monosubstitutions, which is not frequently utilised, although it can be highly advantageous. This is supported with some of the authors’ latest results.     

Scaling effect on the tensile properties of [±45/0/±45/0/±45] Polypropylene/Twaron laminates

The effects of scaling on the mechanical response under tension of balanced nonsymmetrical laminates were investigated for a thermoplastic composite: Polypropylene reinforced with Twaron^® fibers. The composite baseline was an 8-ply laminate which consisted of unidirectional plies arranged in the sequence [±45/0/±45/0/±45]. The influence of specimen size on the tensile properties was studied for one (thickness), two (in-plane) and three (volume) dimensional scaling. The stress-strain curves suggested some variation in laminate behavior owing to the dimensional scaling; nevertheless, a further analysis with the classical lamination theory demonstrated that the observed effect was due to small variations in the fiber volume fraction of the laminates. It was concluded that the mechanical properties of these thermoplastic laminates do not exhibit scaling effects. The failure mechanism of the laminates was studied at macroscopic level; a scale effect of the fracture mechanism was observed.     

空间频率域的张量ABCD定律

运用张量分析方法把轴对称系统中的空间频率域的柯林斯公式推广到一般的非轴对称光学系统,并推导了在空间频率域中适用于非轴对称光学系统的张量ABCD定律。空间频率域中的柯林斯公式和张量ABCD定律直接给出了像散光束的空间傅里叶频谱的传输规律。它们在处理与空间频谱有关的问题,如空间滤波,成像系统的传递函数,复杂像散高斯光束在自由空间的传输等问题时更为简便。     

Cross-spectral density matrix of a random electromagnetic beam propagating through an apertured axially nonsymmetrical optical system

Using the fact that a hard-edged rectangular aperture function can be approximated by a two-dimensional multi-Gaussian series, analytic formulas for the elements of the cross-spectral density matrix of a random electromagnetic beam truncated by a rectangular aperture and passing through an axially nonsymmetrical optical system is derived. The analysis is illustrated by numerical examples relating to changes in the spectral degree of polarization of electromagnetic Gaussian Schell-model beams propagating through free space, focal system and dual-focus system. In particular, the effect of the size of the hard aperture on the spectral degree of polarization of the beam along its optical axis is discussed.     

Off-axial elliptical cosine-Gaussian beams and their propagation properties

In this paper, a new kind of light beam called off-axial elliptical cosine-Gaussian beam (ECosGBs) is defined by using the tensor method. An analytical propagation expression for the ECosGBs passing through axially nonsymmetrical optical systems is derived by using vector integration. The intensity distributions of ECosGBs on the input plane, on the output plane with the equivalent Fresnel number being equal to 0.1 and on the focal plane are respectively illustrated for the propagation properties. The results indicate that an ECosGB is eventually transformed into an elliptical cosh-Gaussian beam. In other words, ECosGBs and cosh-Gaussian beams act in a reciprocal manner after propagation.     

提高相干谐波输出的一种新方法

本文利用自由电子激光(FEL)纵模统一理论讨论了光学速调管自由电子激光相干谐波的输出情况。从物理上分析了非对称光学速调管的设计,得出了采用非对称的光学速调管可使FEL的相干谐波输出提高近30％。     

非对称光学系统的矩阵分解与等效变换

 使用矩阵光学方法研究了非对称光学系统的矩阵分解和等效变换。将Arsenault提出的分解方法推广应用于分块矩阵行列式为零的4×4矩阵的分解，并以用于光束对称化的光学系统为例说明该方法的应用。     

Dynamical relaxations in mixtures of different polymers and nonsymmetrical copolymers in solution

Dynamical relaxation properties of nonsymmetrical mixtures of homopolymers and of copolymers in solution are examined. In particular, examples of bimodal mixtures in solution, ternary mixtures of two different homopolymers and a solvent, and nonsymmetrical diblock copolymers in solution are examined. The frequencies of the eigenmodes Γ and Γ′, those of the cooperative mode Γ_T and the interdiffuse mode Γ_I are calculated for these systems. It is found that the variations of T_T and T_I, with the scattering wave number q are practically identical to those of Γ_T and Γ_I, respectively. This identity is rigorous only for mixtures or copolymers where the two polymer components are identical except for their contrast factors (i.e., indices of refraction or scattering lengths). Here, it is argued that the identification of the eigenmodes with the cooperative and interdiffuse modes can be extended qualitatively to mixtures of different polymers and to nonsymmetrical copolymers in solution.