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71.
In situ photoproduction of dichlorodibenzo-p-dioxin from non-ionic triclosan isolated in solid argon
The infrared spectrum of triclosan [or 5-chloro-2-(2,4-dichlorophenoxy)phenol] isolated in a low temperature (~15 K) argon matrix has been recorded and assigned with help of DFT claculations undertaken with the B3LYP functional and the 6-311++G(d,p) basis set. The obtained spectrum doubtlessly exhibits the characteristic vibrational signature of the neutral (phenol) form of the compound, which exists in two different conformations (forms I and II) in the matrix, in a I: II population ratio of ca. 0.75. Upon broadband UV irradiation of the matrix-isolated triclosan with unfiltered light provided by a xenon arc lamp, formation of 2,8-dichlorodibenzo-p-dioxin (2,8-DCDD) was observed, together with HCl. The reaction seems to occur through initial photoproduction of the triclosan phenol radical derivative, and involve in the initial step participation of dissociative (πσ1) excited states along the OH stretching coordinate, as observed previously for other phenol derivatives. The photochemically detached hydrogen atom derived from triclosan may then react with the closest located chlorine atom in the triclosan molecule to yield HCl and a biradical species, which can subsequently undergo a ring-closure reaction by intramolecular recombination, leading to the observed 2,8-DCDD. 相似文献
72.
Denisov A. P. Bryzgunov M. I. Ivanov A. V. Parkhomchuk V. V. Putmakov A. A. Reva V. B. 《Physics of Particles and Nuclei Letters》2019,16(6):876-884
Physics of Particles and Nuclei Letters - One way to increase the efficiency of electron cooling is to increase the electron density in the beam reference frame. As a rule, with an increase in the... 相似文献
73.
Christian GroßRID=""ID=""Supported by a DFG grant. 《manuscripta mathematica》2000,103(3):339-350
Let denote the eigenspace decomposition of a twisted affine Kac–Moody algebra with respect to an involution , where is a twisted loop algebra, is the center and d is the scaling element of . We endow with the standard bilinear symmetrical form.Then with and carries a Lorentzian signature. Let denote the group that corresponds to , then the adjoint representation of on can be restricted to and this submanifold is isometrical to the Hilbert space E
ε, where is the decomposition of the twisted loop algebra with respect to the induced involutionρ0.We thus obtain an affine representation on E
ε and we show that this representation is polar, i. e., there exists a submanifold that intersects all orbits, and intersects
them orthogonally.
Received: 16 February 2000
RID="
ID="Supported by a DFG grant. 相似文献
74.
Fran?ois DelaunayRID=""ID="" To whom correspondence should be addressed Claire Berthier Michel Lenglet Jean-Michel Lameille 《Mikrochimica acta》2000,132(2-4):337-343
The oxidation in air under isothermal conditions of Inconel 718 has been investigated at 900 °C. We have studied the firsts
stages of the high temperature oxidation mechanism. The oxidised samples were examined using a number of surface analytical
techniques including XPS and SEM-EDS. The results have shown that minor alloying elements strongly influence the oxidation
behaviour of the alloy:
Previous studies had shown that the rate of the external oxide scale growth and the intergranular oxide penetration during
oxidation of Inconel 718 at 900 °C in air are lower than those of Inconel X or Incoloy 800. We suggest that the formation
of a quasi continuous scale of the intermetallic phase Ni3Nb at the oxide-alloy interface could have an important contribution to the good oxidation resistance of Inconel 718. 相似文献
75.
Vladimir V. TretyakovRID=""ID="" To whom correspondence should be addressed Sergey V. Kazakov Alexander V. Bobyl Samuil G. Konnikov 《Mikrochimica acta》2000,132(2-4):365-375
An analytical model of an effective atomic number, Z
eff, for simultaneous calculation of composition and thickness of films on substrates that allows for backscattering processes
is presented. Comparison of dependencies of ϕ(ρz) parameters for film elements on electron beam energy, on atomic numbers of a film and a substrate and on film thickness
was done. The errors inherent in EPMA have been determined by comparing experimental data obtained on YBa2Cu3O7−x bulk crystals with model calculations. Possibility of EPMA as an effective technique for investigation of spatially inhomogeneous
objects was demonstrated by studying the correlation between composition and local superconducting properties (values of critical
temperature and critical current) of these films. 相似文献
76.
Independent Directed Triangles in a Directed Graph 总被引:2,自引:0,他引:2
Hong WangRID=""ID="" This research was supported by UIRC SEED GRANTS–KDY 《Graphs and Combinatorics》2000,16(4):453-462
If D is a directed graph of order n≥3 with , then D contains independent directed triangles. Moreover, the condition on the minimum degree is sharp in general.
Revised: April 19, 1999 相似文献
77.
78.
S. GustafsonRID=""ID=""Present address: Courant Institute Mercer St. New York NY USA.¶E-mail: gustaf@cims.nyu.edu I. M. Sigal 《Communications in Mathematical Physics》2000,212(2):257-275
We study the linearized stability of n-vortex (n∈ℤ) solutions of the magnetic Ginzburg–Landau (or Abelian Higgs) equations. We prove that the fundamental vortices (n = ± 1) are stable for all values of the coupling constant, λ, and we prove that the higher-degree vortices (|n|≥ 2) are stable for λ < 1, and unstable for λ > 1. This resolves a long-standing conjecture (see, eg, [JT]).
Received: 16 November 1998 / Accepted: 3 January 2000
RID="*"
ID="*"Research on this paper was supported by NSERC under grant N7901
RID="**"
ID="**"Present address: Courant Institute, 251 Mercer St., New York, NY 10012, USA.¶E-mail: gustaf@cims.nyu.edu 相似文献
79.
K.?S.?Senthil RaaniEmail authorView authors OrcID profile 《Monatshefte für Mathematik》2017,184(3):459-487
Suppose \(\mu \) is an \(\alpha \)-dimensional fractal measure for some \(0<\alpha <n\). Inspired by the results proved by Strichartz (J Funct Anal 89:154–187, 1990), we discuss the \(L^p\)-asymptotics of the Fourier transform of \(fd\mu \) by estimating bounds of for \(f\in L^p(d\mu )\) and \(2<p<2n/\alpha \). In a different direction, we prove a Hardy type inequality, that is, where \(1\le p\le 2\) and \(E_x=E\cap (-\infty ,x_1]\times (-\infty ,x_2]\ldots (-\infty ,x_n]\) for \(x=(x_1,\ldots x_n)\in {\mathbb R}^n\) generalizing the one dimensional results by Hudson and Leckband (J Funct Anal 108:133–160, 1992).
相似文献
$$\begin{aligned} \underset{L\rightarrow \infty }{\liminf }\ \frac{1}{L^k} \int _{|\xi |\le L}\ |\widehat{fd\mu }(\xi )|^pd\xi , \end{aligned}$$
$$\begin{aligned} \int \frac{|f(x)|^p}{(\mu (E_x))^{2-p}}d\mu (x)\le C\ \underset{L\rightarrow \infty }{\liminf }\frac{1}{L^{n-\alpha }} \int _{B_L(0)}|\widehat{fd\mu }(\xi )|^pd\xi \end{aligned}$$
80.
Frija LM Reva ID Gómez-Zavaglia A Cristiano ML Fausto R 《The journal of physical chemistry. A》2007,111(15):2879-2888
A combined matrix isolation FT-IR and theoretical DFT(B3LYP)/6-311++G(d,p) study of the molecular structure and photochemistry of 5-ethoxy-1-phenyl-1H-tetrazole (5EPT) was performed. A new method of synthesis of the compound is described. Calculations show three minima, very close in energy and separated by low-energy barriers (less than 4 kJ mol-1), in the ground-state potential energy profile of the molecule. The method of matrix isolation enabled the reduction of the number of populated conformational states in the experiment at low temperature due to the effect known as conformational cooling. As a result, the spectrum of the as-deposited matrix of 5EPT closely matches that of the most stable conformer predicted theoretically, pointing to the existence of only this conformer in the low-temperature matrixes. In this structure, the dihedral angle between the two rings, phenyl and tetrazole, is ca. 30 degrees, whereas the ethyl group stays nearly in the plane of the tetrazole ring and is as far as possible from the phenyl group. In situ UV irradiation (lambda > 235 nm) of the matrix-isolated 5EPT induced unimolecular decomposition, which led mainly to production of ethylcyanate and phenylazide, this later compound further reacting to yield, as final product, 1-aza-1,2,4,6-cycloheptatetraene. Anti-aromatic 3-ethoxy-1-phenyl-1H-diazirene was also observed experimentally as minor photoproduct, resulting from direct extrusion of molecular nitrogen from 5EPT. This species has not been described before and is now characterized by infrared spectroscopy for the first time. 相似文献