Histogram shifting (HS) embedding as a typical reversible data hiding scheme is widely investigated due to its high quality of stego-image. For HS-based embedding, the selected side information, i.e., peak and zero bins, usually greatly affects the rate and distortion performance of the stego-image. Due to the massive solution space and burden in distortion computation, conventional HS-based schemes utilize some empirical criterion to determine those side information, which generally could not lead to a globally optimal solution for reversible embedding. In this paper, based on the developed rate and distortion model, the problem of HS-based multiple embedding is formulated as the one of rate and distortion optimization. Two key propositions are then derived to facilitate the fast computation of distortion due to multiple shifting and narrow down the solution space, respectively. Finally, an evolutionary optimization algorithm, i.e., genetic algorithm is employed to search the nearly optimal zero and peak bins. For a given data payload, the proposed scheme could not only adaptively determine the proper number of peak and zero bin pairs but also their corresponding values for HS-based multiple reversible embedding. Compared with previous approaches, experimental results demonstrate the superiority of the proposed scheme in the terms of embedding capacity and stego-image quality.

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The effects of zeolite (HZSM-5 was chosen for use) modified by CeO 2 (CeO 2 /HZSM-5) on the gas-phase elemental mercury (Hg 0 ) removal were investigated under simulated flue gas. The Brunauer−Emmett−Teller surface area analyses, powder X-ray diffraction measurements, and thermogravimetric analyses were employed to characterize the samples. The experimental results showed that there was a synergetic effect between CeO 2 and HZSM-5 on Hg 0 removal. The acidic sites of HZSM-5 could effectively adsorb Hg 0 from the flue gas, and CeO 2 could significantly enhance the oxidation of adsorbed Hg 0 . However, the surface area of CeO 2 /HZSM-5 decreased because of excess CeO 2 , which was detrimental to its Hg 0 removal efficiency. Moreover, the temperature tests manifested that 6% CeO 2 /HZSM-5 achieved high Hg 0 removal efficiency at low reaction temperatures (<300 °C). Additionally, the Hg 0 removal efficiencies of CeO 2 /HZSM-5 were found to be significantly affected by the flue gas components. In the presence of O 2 , promotional effects of NO and SO 2 on the Hg 0 removal were found, while the presence of H 2 O inhibited the Hg 0 removal in this experiment. Furthermore, after regeneration, CeO 2 /HZSM-5 still possessed good reactivity and its Hg 0 removal efficiency stayed above 92% in 30 h.

Gas-phase photoelectron spectroscopy and theoretical calculations are used to study the electronic structure of 1,2-dichalcogenins. Photoelectron spectra are reported for 1,2-dithiin, 3,6-dimethyl-1,2-dithiin, 3,6-diisopropyl-1,2-dithiin, 3,6-di-tert-butyl-1,2-dithiin, 2-selenathiin, 1,2-diselenin, 3,6-dimethyl-1,2-diselenin, and 3,6-di-tert-butyl-1,2-diselenin and are assigned on the basis of (a) trends in ionization cross sections as the ionization photon energy is varied and (b) shifts of the ionizations as chemical substitutions are made. The calculated properties of 1,2-dithiin and 3,6-dimethyl-1,2-dithiin are compared to experimental results. The first four filled frontier valence orbitals are associated with orbitals that can be described as being primarily carbon π and chalcogen lone pair in character. Comparison of spectra collected with He I, He II, and Ne I ionization sources for each compound indicate that there is a large degree of mixing of chalcogen and carbon character through most of the valence orbitals. The highest occupied molecular orbital of the selenium-containing compounds has more chalcogen character than the highest occupied molecular orbital of the 1,2-dithiins. The photoelectron spectra of 1,2-dithiin and 1,2-diselenin contain a sharp ionization that corresponds to removal of an electron from an orbital that is predominantly chalcogen−chalcogen σ bonding in character. The narrow ionization profile indicates fairly weak chalcogen−chalcogen σ bonding in this orbital, which would result in a corresponding weakly antibonding chalcogen−chalcogen σ* orbital. Computational results show that an orbital that is primarily S−S σ* in character is the lowest unoccupied molecular orbital of 1,2-dithiin, and electronic transition calculations show a low-energy HOMO-to-LUMO transition that can be described as a π/lone pair-to-σ* transition that explains the unusual color of 1,2-dichalcogenins.

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Hexanuclear lanthanide(III)-chromium(III) complexes [Ln2(μ-ox){Cr(bipy)(μ-ox)(ox)}4(H2O)6]·13H2O (Ln = Pr 1, Gd 2) (bipy = 2,2′-bipyridine and ox = oxalate dianion) have been synthesized by reaction of [Cr(bipy)(ox)2]− building blocks with Ln(III) ions. The structure of 1 has been determined by X-ray crystallography.

Pyrazoline derivatives as valuable five-membered heterocyclic compounds could be readily prepared through the intramolecular cyclization of ketazines. In this paper, transition metals (Zn 2+ , Cu 2+ , Cr 3+ , Mn 2+ , Co 2+ , Ni 2+ , and Fe 3+ ) were applied for the catalytic synthesis of 3,5,5-trimethyl-2-pyrazoline, and FeCl 3 showed the best catalytic performance with 95% conversion and 99% selectivity. Substrate screening exhibited that the steric hindrance of ketazines is a key factor on the conversions of R-substituted pyrazolines, following the order of R as methyl (95%) > ethyl (83%) > propyl (68%) > butyl (55%). Moreover, the mechanism of the cyclization of ketazines catalyzed by FeCl 3 is calculated by density functional theory. The energetic profile shows that the cyclization reaction consists of two steps and FeCl 3 can efficiently reduce their barrier energies. This work provides a feasible method for the preparation of pyrazoline derivatives using inexpensive, less toxic, and environmentally friendly FeCl 3 as a catalyst.