No abstract

No abstract

Carbonate esters and esters are widely used in the pharmaceutical industry. It is important to enrich the vapor−liquid equilibrium (VLE) database of these components. In this article, the isobaric VLE data of three binary mixtures diethyl carbonate (DEC) + methyl acetate, DEC + n-propyl acetate, and DEC + amyl acetate at 100.17 kPa were obtained. The experimental data were tested using the Van Ness consistency test, which indicated that the experimental data satisfy the test for thermodynamic consistency. The activity coefficient models Wilson, NRTL, and UNIQUAC were used to correlate the experimental VLE values to obtain the interaction parameters. The results associated with the three models are in good agreement with the experimental data. The minimum average absolute deviation values of vapor-phase compositions and temperatures for all are 0.0010 and 0.15 K, and no azeotropic behavior was observed in these systems. In addition, the group contribution method was used to fit the group parameters of the vapor−liquid equilibrium data.

It is of great importance to locate lines quickly and robustly in images. In this paper, a new method based on a binary image pyramid and Hough transform is developed to extract lines fast and accurately in two steps. Lines are quickly detected via a two-dimensional Hough transform in a lower-resolution image on a pyramid's top, and then they are finely located via a one-dimensional Hough transform in the original image at the pyramid's bottom. The proposed method has good ability to detect lines in noisy images, with reduced computation cost and storage requirement. The performance analysis and experiments are provided to verify the effectiveness of the proposed method.

Introducing a 4′-C-trifluoromethyl (4′-CF3) modification into oligodeoxynucleotides (ODNs) leads to improved nuclease resistance and increased cell permeability.

Partial oxidation of methane (CH4) to methanol (CH3OH) remains a great challenge in the field of catalysis due to its low selectivity and productivity. Herein, Ag–O–Ag/graphene and Cu–O–Ag/graphene composite catalysts are proposed to oxidize methane (CH4) to methanol (CH3OH) by using the first-principles calculations. It is shown that reactive oxygen species (μ-O) on both catalysts can activate the C–H bond of CH4, and in addition to CH4 activation, the catalytic activity follows the order of Ag–O–Ag/graphene (singlet) > Ag–O–Ag/graphene (triplet) ≈ Cu–O–Ag/graphene (triplet) > Cu–O–Ag/graphene (singlet). For CH3OH* formation, the catalytic activity follows the order of Cu–O–Ag/graphene (triplet) > Ag–O–Ag/graphene (triplet) > Ag–O–Ag/graphene (singlet) > Cu–O–Ag/graphene (singlet). It can be inferred that the introduction of Cu not only reduces the use of noble metal Ag but also exhibits a catalytic effect comparable to that of the Ag–O–Ag/graphene catalyst. Our findings will provide a new avenue for understanding and designing highly effective catalysts for the direct conversion of CH4 to CH3OH.

No abstract

No abstract