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21.
The molecular structure and conformation of 2,3-dichloro-1-propene have been determined by gas-phase electron diffraction at nozzle temperatures of 24, 90 and 273°C. The molecules exist as a mixture of two conformers with the chlorine atoms anti (torsion angle ∠φ = 0°) or gauche (∠φ = 109°) to each other and with the anti form the more stable. The composition (mole fraction) of the vapor with uncertainties estimated at 2σ was found to be 0.55 (0.08), 0.49 (0.08) and 0.41 (0.10) at 24, 90 and 273°, respectively. These values correspond to an energy difference with estimated standard deviation ΔE° = E°g-E°a = 0.7 ± 0.3 kcal mol?1 and an entropy difference ΔS° = S°g-S°a = 0.6 ± 0.9 cal mol?1 K?1. Some of the diffraction results, together with spectroscopic observations, permit the evaluation of an approximate torsional potential function of the form 2V = V1 (1 - cos φ) + V2 (1 - cos 2φ) + V3 (1 - cos 3φ); the results are V1 = 4.4 ± 0.5, V2 = ?2.9 ± 0.5 and V3 = 4.8 ± 0.2, all in kcal mol?1. The results at 24°C for the distance (ra) and angle (∠α) parameters, with estimated uncertainties of 2σ, are: r(Csp2-H) = 1.098(0.020)Å, r(Csp3-H) = 1.103(0.020)Å, r(CC) = 1.334(0.009)Å, r(C-C) = 1.504(0.013)Å, r(Csp2-Cl) = 1.752(0.021)Å, r(Csp3-Cl) = 1.776(0.020)Å, ∠C-CC = 127.6(1.1)°, ∠Csp3-Csp2-Cl = 110.2(1.0), ∠Csp2-Csp3-Cl = 113.1(1.2)°, ∠H-Csp3-H = 109.5° (assumed), ∠CC-H = 120.0° (assumed) and ∠φ = 108.9(3.4)°.  相似文献   
22.
Minh  Hà Quang 《Positivity》2020,24(3):631-662
Positivity - The current work generalizes the author’s previous work on the infinite-dimensional Alpha Log-Determinant (Log-Det) divergences and Alpha-Beta Log-Det divergences, defined on the...  相似文献   
23.
Russian Physics Journal - The double coaxial resonator with a shortening capacitance is calculated by the partial volume method. The double resonator is represented by two single coaxial resonators...  相似文献   
24.
The aim of this paper is to give some criterions for holomorphy of F-valued σ(F, W)-holomorphic functions which are bounded on bounded sets in a domain D of Fréchet spaces E (resp. ${\mathbb{C}^n}$ ) where ${W \subset F'}$ defines the topology of Fréchet space F. Base on these results we consider the problem on holomorphic extension of F-valued σ(F, W)-holomorphic functions from non-rare subsets of D and from subsets of D which determines uniform convergence in H(D). As an application of the above, some theorems of Vitali-type for a locally bounded sequence ${\{f_i\}_{i \in \mathbb{N}}}$ of Fréchet-valued holomorphic functions are also proved.  相似文献   
25.
This work is a continuation of [7]. In that paper, a sufficient condition was given on a real analytic fmlction g defined near 0 in C so that the algebra generated by z2 and g2 is dense in the space of continuous functions on D for all disks D close enough to the origin in C. By using the same methods and some ideas taken from the first named author's thesis we deal with the case where g is only of class C1 near 0.  相似文献   
26.
27.
A sharp almost sure bound is derived for limit points of average sum of weakly dependent random variables, which ensures strong laws of large numbers for and -mixing random variables, without assumptions on rate of tending to zero of and -mixing parameters n and n.  相似文献   
28.
In this paper p-adic analogs of the Lichtenbaum Conjectures are proven for abelian number fields F and odd prime numbers p, which generalize Leopoldt's p-adic class number formula, and express special values of p-adic L-functions in terms of orders of K-groups and higher p-adic regulators. The approach uses syntomic regulator maps, which are the p-adic equivalent of the Beilinson regulator maps. They can be compared with étale regulators via the Fontaine-Messing map, and computations of Bloch-Kato in the case that p is unramified in F lead to results about generalized Coates-Wiles homomorphisms and cyclotomic characters. Oblatum 14-V-96 & 9-X-97  相似文献   
29.
    
Zeolitic aluminophosphate, a three-dimensional microporous material, with an average pore size of 0.38 nm is good candidate for molecular sieve application in CO2 gas separation. The separation of CO2/CH4 gas mixtures for precombustion processes is desirable from the standpoint of both environmental concerns and energy efficiency. This study concerns an environmentally friendly method to synthesize zeolitic aluminophosphate thin films on various configurations and low-cost kaolin porous substrates with high performance in the separation of CO2/CH4 mixtures. The membranes are prepared by a gelless seed growth method that uses lower amounts of chemicals, forms no liquid gel, chemical waste, or byproducts and generates no washing water. The obtained membranes show very high selectivity for CO2 with a CO2/CH4 separation factor above 1000 in the separation of CO2/CH4 gas mixtures.  相似文献   
30.
    
Antioxidant and photoprotective properties of two natural acridone derivatives namely Paratrimerin C ( 1 ) and Citrusinine‐I ( 2 ) have been studied by DFT and TD‐DFT at the M05‐2X/6‐311++G(3df, 3p)//M05‐2X/6‐31+G(d) level of theory. Three common mechanisms characterized for the antioxidant properties including H‐atom transfer (HAT) and proton transfer (PT) towards HOO/HO radicals and single electron transfer (SET) were investigated in the gas phase, water and pentyle thanoate. The DFT results revealed that both compounds can efficiently scavenge HOO and HO radicals via HAT mechanism in all media. Particularly, the HAT reactions of 2 with HO radical in water are the most favored reaction (∆H ‐37.7 kcal/mol). In addition, the efficient UV‐absorption ability of the studied compound was elucidated by TD‐DFT. All compounds can absorb UV radiations in the range of 200‐335 nm, for which the easiest excitations are at 334‐332 nm and the strongest absorptions were found at 234‐227 nm, for 1 and 2 , respectively. The HOMO to LUMO and HOMO‐3 to LUMO (π‐π*) transitions are assigned for the corresponding UV‐absorption.  相似文献   
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