(5E)-2-[4,5-Bis(methyl­sulfan­yl)-1,3-dithiol-2-yl­idene]-5-(4-iodo-1,3-dithiol-2-yl­idene)-1,3-dithio­lan-4-one

The mol­ecular framework of the title compound, C11H7IOS8, is almost planar [maximum deviation = 0.040 (4) Å], except for the two methyl­sulfanyl groups, which are twisted relative to the mol­ecular skeleton, making C—S—C—C torsion angles of 144.1 (8) and −141.3 (8)°. In the crystal, mol­ecules are stacked alternately in opposite orientations, forming a one-dimensional column parallel to [110]. The primary inter­actions between mol­ecules comprising the columns are of the S⋯S type [3.554 (1) Å]. Inter­actions between columns are of the S⋯S type [3.411 (1) along b and 3.444 (1) Å along c], as well as S⋯I contacts [3.435 (2) Å]

5-(4,5-Diiodo-1,3-dithiol-2-yl­idene)-4′,5′-bis­(methyl­sulfan­yl)-2,2′-bi-1,3-dithiole-4(5H)-thione

The mol­ecular skeleton of the title mol­ecule, C11H6I2S9, is nearly planar [maximum deviation 0.052 (3) Å] except for the two methyl groups. In the crystal, mol­ecules related by translation along b axis are associated into columns through π–π inter­actions between the five-membered rings, with a centroid–centroid distance of 3.593 (5) Å. Inter­action between adjacent columns is accomplished by short S⋯I contacts of 3.2099 (4) Å

Dispensabilities of Carbonic Anhydrase in Proteobacteria

Carbonic anhydrase (CA) (E.C. 4.2.1.1) is a ubiquitous enzyme catalysing interconversion between CO2 and bicarbonate. The irregular distribution of the phylogenetically distinct classes of CA in procaryotic genome suggests its complex evolutionary history in procaryotes. Genetic evidence regarding the dispensability of CA under high-CO2 air in some model organisms indicates that CA-deficient microorganisms can persist in the natural environment by choosing high-CO2 niches. In this study, we studied the distribution of CA in the genome of Proteobacteria. While a large majority of the genome-sequenced Proteobacteria retained a CA gene(s), intracellular bacterial genera such as Buchnera and Rickettsia contained CA-defective strains. Comparison between CA-retaining and CA- deficient genomes showed the absence of whole coding sequence in some strains and the presence of frameshifted coding sequence in other strains. The evidence suggests that CA is inactivated and lost in some proteobacteria during the course of evolution based on its dispensability

Finite-mm scaling analysis of Berezinskii-Kosterlitz-Thouless phase transitions and entanglement spectrum for the six-state clock model

We investigate the Berezinskii-Kosterlitz-Thouless transitions for the square-lattice six-state clock model with the corner-transfer matrix renormalization group (CTMRG). Scaling analyses for effective correlation length, magnetization, and entanglement entropy with respect to the cutoff dimension $m$ at the fixed point of CTMRG provide transition temperatures consistent with a variety of recent numerical studies. We also reveal that the fixed point spectrum of the corner transfer matrix in the critical intermediate phase of the six-state clock model is characterized by the scaling dimension consistent with the $c=1$ boundary conformal field theory associated with the effective $Z_6$ dual sine-Gordon model.Comment: 7 pages, 7 figures, to appear in Phys. Rev.

Integrated Method to Evaluate Acid Stimulation of Horizontal Wells in Carbonate Reservoir through Treatment Pressure Analysis

Unlocking a tight carbonate formation for oil and gas production by multi-stage acid stimulation is a relatively cost-effective method as an alternative to propped fracturing for production enhancement. Depending on whether treatment pressure is below or above the formation closure stress, acid stimulation is basically divided into matrix acidizing and acid fracturing. In this study, practical methodology to evaluate both matrix acidizing and acid fracturing through treatment monitoring is presented respectively. For matrix acidizing, monitoring and optimizing a matrix acidizing has been achieved by integrating a forward model used in acidizing design for horizontal wells with a real-time monitoring model for skin evolution during the stimulation. The effect of acidizing is described as an overall skin factor change, and productivity improvement is predicted for the treatment. Then the field treatment data monitored on-site was used to estimate the skin response by treatment injection. History matching procedure of design and actual treatment data will be carried out to update near-wellbore and key wormholing parameters. Through sensitivity study, which parameter should be updated is discussed. Finally optimum rate schedule is identified based on updated parameters. Meanwhile, for acid fracturing treatment, new method for real-time monitoring of acid fracturing, the inverse injectivity vs. superposition time function plot is proposed, subject to the condition that the treatment pressure is above closure pressure after the breakdown. Combining a linear dual-porosity transient slab model with injectivity concept, actual growing cross-sectional area induced by acid fracturing treatment can be monitored in real-time. After production starts, linear flow diagnostic approach with rate-transient analysis provides cross-sectional area flowing from matrix, which is compared with the area induced by acid fracturing during the stimulation. The treatment efficiency provides engineers with additional information as to whether the designed acid fracturing was performed appropriately under the in-situ closure stress field. A field case example of both multi-stage matrix acidizing and acid fracturing acid in horizontal well are also presented respectively in the study to illustrate the application of the approach developed, and to show the value of the integrated approach to monitor and diagnose acid stimulation in horizontal wells

The shielding effect of HTS power cable based on E-J power law

A method for analysing the current distribution in high-T/sub c/ superconducting (HTS) power cable is examined by the aid of the novel use of anisotropic conductivity and 3-D finite element method considering E-J power law characteristic. The detailed current distribution in the cable is illustrated and the shielding effect of HTS shield layer with intervals is also examined. It is shown that AC losses in shield layer with intervals are increased when the interval between wires becomes large

2,5-Bis(1,3-dithiol-2-yl­idene)-1,3-dithiol­ane-4-thione

The asymmetric unit of the title compound, C9H4S7, contains two independent mol­ecules, in one of which the central five-membered ring is disordered over two orientations in a 0.924 (3):0.076 (3) ratio. The mol­ecular skeleton is almost planar: the average distance of the atoms from their mean plane is 0.128 (7) Å in the ordered mol­ecule, and 0.088 (5) and 0.123 (2) Å in the major and minor disorder components, respectively. The ordered and disordered mol­ecules form separate columns by stacking along the b axis. Adjacent columns inter­act via short S⋯S [3.33 (2), 3.434 (3), 3.444 (2), 3.503 (2), 3.519 (3) and 3.53 (4) Å] and S⋯H [2.814 (2), 2.87 (7), 2.92 (2), 2.9269 (18), 2.93 (2), 2.94 (2), 2.939 (2), 2.967 (2) and 2.974 (1) Å] contacts