Thermodynamics of phase transition in higher dimensional Reissner-Nordstr\"{o}m-de Sitter black hole

It is well known that there are black hole and the cosmological horizons for the Reissner-Nordstr\"{o}m-de Sitter spacetime. Although the thermodynamic quantities on the horizons are not irrelevant, they satisfy the laws of black hole thermodynamics respectively. In this paper by considering the relations between the two horizons we give the effective thermodynamic quantities in $(n+2)$-dimensional Reissner-Nordstr\"{o}m-de Sitter spacetime. The thermodynamic properties of these effective quantities are analyzed, moreover, the critical temperature, critical pressure and critical volume are obtained. We carry out an analytical check of Ehrenfest equations and prove that both Ehrenfest equations are satisfied. So the spacetime undergoes a second order phase transition at the critical point. This result is consistent with the nature of liquid--gas phase transition at the critical point, hence deepening the understanding of the analogy of charged dS spacetime and liquid--gas systems.Comment: 18 pages, 7 figures, 1 tabl

Phase transition of the higher dimensional charged Gauss-Bonnet black hole in de Sitter spacetime

We study the phase transition of charged Gauss-Bonnet-de Sitter (GB-dS) black hole. For black holes in de Sitter spacetime, there is not only black hole horizon, but also the cosmological horizon. The thermodynamic quantities on the both horizons satisfy the first law of the black hole thermodynamics, respectively; moreover, there are additional connections between them. Using the effective temperature approach, we obtained the effective thermodynamic quantities of charged GB-dS black hole. According to Ehrenfest classification, we calculate some response functions and plot their figures, from which one can see that the spacetime undergoes a second-order phase transition at the critical point. It is shown that the critical values of effective temperature and pressure decrease with the increase of the value of GB parameter $\alpha$.Comment: 9 pages, 16 figure

catena-Poly[[diazido­manganese(II)]bis­[μ-1-(4-pyridylmeth­yl)-1H-benzimidazole]]

In the title polymeric compound, [Mn(N3)2(C13H11N3)2]n, each MnII centre is six-coordinated in an octahedral geometry by six N atoms from four 1-(4-pyridylmeth­yl)-1H-benzimidazole (L) ligands and two azide anions (N3 −). Each of the MnII ions lies on an inversion centre. The L ligands and N3 − anions bridge adjacent MnII centres, generating a polymeric chain running along the [110] direction. Adjacent polymeric chains are arranged in a two-dimensional network parallel to the (001) plane, linked by C—H⋯N hydrogen bonds

Hydrate-based CO2 (carbon dioxide) capture from IGCC (integrated gasification combined cycle) synthesis gas using bubble method with a set of visual equipment

The hydrate-based carbon dioxide (CO2) capture from the integrated gasification combined cycle (IGCC) synthesis gas using the bubble method is investigated with a set of visual equipment in this work. The gas bubble is created with a bubble plate on the bottom of the equipment. By the visual equipment, the hydrate formation and the hydrate shape are visually captured. With the move of the gas bubble from the bottom to the top of the reactor, gas hydrate forms firstly from the gas-liquid boundary around the bubble, then the hydrate gradually grows up and piles up in the bottom side of the bubble to form a hydrate particle. The gas hydrate shape is affected by the gas flow rate. The hydrate is acicular crystal at the low gas flow rate while the hydrate is fine sand-like crystal at the high gas flow rate. The bubble size and the gas flow rate have an obvious impact on the hydrate-based CO2 separation process. The experimental results show the gas bubble of 50 mu m and the gas flow rate of 6.75 mL/min/L are ideal for CO2 capture from IGCC synthesis gas under the condition of 3.0 MPa and 274.15 K. (C) 2012 Elsevier Ltd. All rights reserved.</p

{4-Bromo-2-[3-(diethyl­ammonio)propyl­imino­meth­yl]phenolato}diiodidozinc(II) methanol solvate

In the title complex, [ZnI2(C14H21BrN2O)]·CH3OH, the asymmetric unit consists of a mononuclear zinc(II) complex mol­ecule and a methanol solvent mol­ecule. The compound was derived from the zwitterionic form of the Schiff base 4-bromo-2-[3-(diethyl­amino)propyl­imino­meth­yl]phenol. The ZnII atom is four-coordinated by the imine N and phenolate O atoms of the Schiff base ligand and by two iodide ions in a distorted tetra­hedral coordination. In the crystal structure, the methanol mol­ecules are linked to the Schiff base mol­ecules through N—H⋯O and O—H⋯O hydrogen bonds. One I atom is disordered over two positions in a 0.702 (19):0.298 (19) ratio

{4-Bromo-2-[2-(piperidin-1-ium-1yl)ethyl­iminometh­yl]phenolato}diiodido­zinc(II)

In the title complex, [ZnI2(C14H19BrN2O)], the ZnII atom is four-coordinated by the imine N and phenolate O atoms of the Schiff base ligand and by two iodide ions in a distorted tetra­hedral coordination. In the crystal structure, mol­ecules are linked through inter­molecular N—H⋯O hydrogen bonds, forming chains running along the b axis

Diiodido[N′-(2-methoxy­benzyl­idene)-N,N-dimethyl­ethane-1,2-diamine]zinc(II)

In the title complex, [Zn(C12H18N2O)I2], the ZnII ion is four-coordinated by the imine N and amine N atoms of the Schiff base ligand and by two iodide ions in a distorted tetra­hedral coordination