The spectral sensitivity of onium salt photoinitiators in cationic polymerization can be tuned from the short wavelength region of the UV spectrum to wavelengths up to the visible region by using direct and indirect activation, respectively. Indirect activation is based on the electron transfer reactions between onium salts and free radical photoinitiators, appropriate sensitizers and compounds capable of forming charge transfer complexes. Bisacylphosphine oxides, dimanganese decacarbonyl in conjunction with alkyl halides and titanocene type photoinitiators such as Irgacure 784 were shown to be useful free radical promoters providing the possibility of performing cationic polymerization in the long wavelength and visible region. The synthetic routes to prepare block copolymers by using electron transfer photosensitization and free radical promoted cationic polymerization are also described. 相似文献
A novel α,ω‐heterofunctional poly(ethylene oxide) (PEO) macromonomer possessing methacryloyl and thienyl end groups was prepared by ring‐opening polymerization of ethylene oxide initiated by potassium thienylethoxide and termination of the living PEO ends with methacryloyl chloride. Incorporation of methacryloyl and thienyl groups was confirmed by free‐radical and oxidative polymerization processes, respectively, and by means of 1H NMR analysis.
In this study, a more general version of F-expansion method is proposed. With this offered method, more than one Jacobi elliptic functions are located in the solution function. We seek analytical solutions of the space-time fractional cubic Schrodinger equation by use of the new type of F-expansion method. Consequently, multifarious exact analytical solutions consisting of single, double, and multiple combined Jacobi elliptic functions solutions are acquired. 相似文献
A uniform version of the potential function of the Maggi-Rubinowicz boundary diffraction wave theory is obtained by using the large argument expansion of the Fresnel integral. The derived function is obtained for the problem of diffraction of plane waves by a circular edge. The results are plotted numerically. 相似文献
The electronic structure and optical properties of one-electron Quantum Dot (QD) with and without an on-center impurity were investigated by assuming a spherically symmetric confining potential of finite depth. The energy eigenvalues and the state functions of QD were calculated by using a combination of Quantum Genetic Algorithm (QGA) and Hartree–Fock Roothan (HFR) method. We have calculated the binding energy for the states 1s,1p,1d,1f, oscillator strengths, the linear and third-order nonlinear optical absorption coefficients as a function of the incident photon energy and incident optical intensity for the 1s–1p, 1p–1d and 1d–1f transitions. The existence of the impurity has great influence on the optical absorption spectra and the oscillator strengths. Also we found that the magnitudes of the total absorption coefficients of the spherical QD increase for transitions between higher states. 相似文献
2-Bromomethyl-3-aryl-2-propenoic acids have been synthesized from Baylis-Hillman adducts derived from aromatic aldehydes and t-butyl acrylates as new precursors in MBH chemistry. Further triolides were synthesized by the cyclo-oligomerization of 2-bromomethyl-3-aryl-2-propenoic acids in the presence of Cs2CO3 demonstrating the synthetic utility of these motifs. 相似文献
We report the results of detailed experimental and theoretical studies on the molecular structure and vibrational spectra of metal(II) halide complexes of 1,3-bis(4-pyridyl)propane [M(N2C13H14)X2, where M represents Zn or Hg, and X represents Cl, Br, or I]. The FT–infrared spectra (FT-IR) and FT-Raman spectra of the metal complexes of the 1,3-bis(4-pyridyl)propane molecule in the powder form were recorded between the 400–4000 and 5–3500 cm?1 regions, respectively. The molecular geometry and vibrational frequencies of the metal complexes of 1,3-bis(4-pyridyl)propane in the ground state were calculated using density functional theory (B3LYP functional) with LANL2DZ and SDD as basis sets. The total energy distributions (TED) among the symmetry coordinates of the normal modes were computed for the low-energy structure of the molecules. Complete vibrational assignments based on the calculated TED values are given. 相似文献