2,910 research outputs found
Positive loop-closed automata: a decidable class of hybrid systems
AbstractThe model-checking problem for real-time and hybrid systems is very difficult, even for a well-formed class of hybrid systems—the class of linear hybrid automata—the problem is still undecidable in general. So an important question for the analysis and design of real-time and hybrid systems is the identification of subclasses of such systems and corresponding restricted classes of analysis problems that can be settled algorithmically. In this paper, we show that for a class of linear hybrid automata called positive loop-closed automata, the satisfaction problem for linear duration properties can be solved by linear programming. We extend the traditional regular expressions with duration constraints and use them as a language to describe the behaviour of this class of linear hybrid automata. The extended notation is called duration-constrained regular expressions. Based on this formalism, we show that the model-checking problem can be reduced formally to linear programs
(2,9-Dimethyl-1,10-phenanthroline-κ2 N,N′)bis(2-hydroxybenzoato)-κO;κ2 O,O′-cobalt(II)
In the title compound, [Co(C7H5O3)2(C14H12N2)], the CoII ion is five-coordinated by two N atoms from one 2,9-dimethyl-1,10-phenanthroline (dmphen) ligand and three O atoms from two 2-hydroxybenzoate anions in a distorted trigonal bipyramidal geometry. The carboxylate group of one of the two 2-hydroxybenzoate anions is monodentate with a normal Co—O distance [1.9804 (18) Å], while the other is bidentate with two longer Co—O bonds [2.1981 (18) and 2.1359 (19) Å]. The crystal structure is stabilized by aromatic π–π stacking interactions [centroid–centroid distances of 4.0380 (3) and 3.8216 (3) Å between dmphen/dmphen and benzene/dmphen rings, respectively] and C—H⋯π(benzene) interactions
Aqua(2,9-dimethyl-1,10-phenanthroline-κ2 N,N′)bis(2-hydroxybenzoato-κO)manganese(II) 2,9-dimethyl-1,10-phenanthroline hemisolvate
In the asymmetric unit of the title complex, [Mn(C7H5O3)2(C14H12N2)(H2O)]·0.5C14H12N2, the MnII ion is coordinated by a bidentate 2,9-dimethyl-1,10-phenanthroline (dmphen) molecule, one water molecule and two monodentate 2-hydroxybenzoate anions in a distorted trigonal-bipyramidal geometry. The OH group of the 2-hydroxybenzoate anion is disordered over two positions with site-occupancy factors of 0.5. The asymmetric unit is completed with by an uncoordinated half-molecule of dmphen, disordered about a crystallographic twofold axis. In the crystal structure, molecules are linked into a two-dimensional framework by O—H⋯N, O—H⋯O and C—H⋯O hydrogen bonds. The packing of the structure is further stabilized by π–π stacking interactions involving dmphen molecules, with centroid–centroid separations of 3.8027 (3) and 3.6319 (3) Å
Aqua(dicyanamido-κN 1)(2,9-dimethyl-1,10-phenanthroline-κ2 N,N′)(nitrato-κ2 O,O′)cobalt(II)–2,9-dimethyl-1,10-phenanthroline–water (2/1/2)
In the title compound, 2[Co(C2N3)(NO3)(C14H12N2)(H2O)]·C14H12N2·2H2O, the CoII ion is coordinated by a bidentate 2,9-dimethyl-1,10-phenanthroline (dmphen) ligand, a bidentate nitrate anion, a water molecule and a monodentate dicyanamide group in a distorted octahedral geometry. One uncoordinated dmphen molecule is situated on a crystallographic twofold axis and the asymmetric unit is completed by one water molecule. In the crystal, molecules form a one-dimensional framework in the [001] direction through O—H⋯N and O—H⋯O hydrogen bonds. The crystal packing is further stabilized by π–π stacking interactions between the dmphen rings of neighboring molecules, with a centroid–centroid separation of 3.5641 (8) Å and a partially overlapped arrangement of parallel dmphen rings with a distance of 3.407 (2) Å
catena-Poly[[(2,9-dimethyl-1,10-phenanthroline-κ2 N,N′)lead(II)]-di-μ-2-hydroxybenzoato-κ3 O 1,O 1′:O 2;κ3 O 2:O 1,O 1′]. Corrigendum
Corrigendum to Acta Cryst. (2007), E63, m2678
Bis(μ-3-hydroxybenzoato-κ3 O,O′:O)bis[aqua(3-hydroxybenzoato-κ2 O,O′)(1,10-phenanthroline-κ2 N,N′)lead(II)] monohydrate
In the centrosymmetric binuclear title complex, [Pb2(C7H5O3)4(C12H8N2)2(H2O)2]·H2O, each Pb atom is eight-coordinated in a PbO6N2 environment by two N atoms from the 1,10-phenanthroline (phen) ligand, five carboxylate O atoms from four 3-hydroxybenzoate anions and one O atom from the coordinated water molecule in a distorted bicapped trigonal-prismatic geometry. The benzoate groups coordinate each PbII atom in two different ways. Two benzoate ions behave as bidentate ligands to the Pb atom, and another benzoate ion bridges the Pb atoms, forming a binuclear structure. The dimeric units are packed via O—H⋯O hydrogen bonds and π–π interactions between the aromatic rings of neighboring molecules, with centroid–centroid distances of 3.552 (2) and 3.641 (2) Å
Thermoset Shape‐Memory Polyurethane with Intrinsic Plasticity Enabled by Transcarbamoylation
Thermoset polymers are known for their superior thermomechanical properties, but the chemical crosslinking typically leads to intractability. This is reflected in the great differences between thermoset and thermoplastic shape‐memory polymers; the former exhibit a robust shape memory but are not capable of redefining the permanent shape. Contrary to current knowledge, we reveal here that a classical thermoset shape‐memory polyurethane is readily capable of permanent reshaping (plasticity) after a topological network rearrangement that is induced by transcarbamoylation. By employing the Jianzhi technique (also known as kirigami), unexpected shape‐shifting versatility was observed for this otherwise classical material. As the essential carbamate moiety in polyurethanes is one of the most common polymer building units, we anticipate that our finding will have significant benefits beyond shape shifting.Thermoset polymers are known for their superior thermomechanical properties, but the chemical crosslinking typically leads to intractability. However, a classical thermoset shape‐memory polyurethane was now shown to be readily capable of permanent reshaping (plasticity) after a topological network rearrangement that is induced by transcarbamoylation.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137615/1/anie201602847.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137615/2/anie201602847-sup-0001-misc_information.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137615/3/anie201602847_am.pd
The economic burden of chronic neurological disease
Figure S2. Forest plots of the 5 studies evaluating the association between EP and endometriosis according to the endometriosis stage (stage 4 versus stage 1, and stages 3â4 versus stages 1â2). (TIFF 2134 kb
Bis(benzoato-κ2 O,O′)(2,9-dimethyl-1,10-phenanthroline-κ2 N,N′)cobalt(II)
In the title compound, [Co(C7H5O2)2(C14H12N2)], the CoII ion is located on a twofold rotation axis and is chelated by a 2,9-dimethyl-1,10-phenanthroline (dmphen) ligand and two benzoate anions in a distorted octahedral geometry. The crystal packing is stabilized by π–π interactions between parallel dmphen ligands of neighbouring molecules, with a face-to-face distance of 3.411 (2) Å
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