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Aminou Mohamadou Gerard A. van Albada Ilpo Mutikainen Urho Turpeinen Jan Reedijk 《Inorganic chemistry communications》2010,13(10):1221-1224
A novel hexagonal-based honeycomb compound with overall formula {[KCr(C2O4)3][Cu(pypn)(H2O)](H2O)4} is reported in which pypn is with the tetradentate ligand (N,N′-bis(2-pyridylmethyl)-1,3-propanediamine). The [KCr(C2O4)3]2? moiety forms a hexagonal honeycomb structure, while the five-coordinated [Cu(pypn)(H2O)]2+ moiety is located in between the layers, partly filling the holes in the cavities. The synthesis, X-ray crystal structure and some spectroscopic properties are presented. The coordination of Cr(III) is octahedral, with a CrO6 chromophore, and the K+ ion is in a KO6 environment (K–O distances vary from 2.36 to 2.48 ?). The [KCr(C2O4)3]2? layers have the K+ ions in a Λ conformation, while the Cr(III) ions in the Δ conformation. The geometry around the Cu(II) is five-coordinated with four nitrogens from the chelating pypn ligand in a plane and the apical position being occupied by the oxygen atom of the coordinating water molecule. The packing of the cationic and the anionic layers appears to be of special interest. 相似文献
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Yu-Fei Song Wei Chen Jinfeng Chu Guangxun Su Ilpo Mutikainen Urho Turpeinen Jan Reedijk 《Inorganic chemistry communications》2010,13(12):1538-1541
The dinuclear compound, 1, with the molecular formula of [Cu2(H3L)2(ClO4)2][Cu2(H3L)2(MeCN)2](ClO4)6 was prepared by the reaction of [bis-(1H-imidazol-2-yl)-methyl]-pyridin-2-yl-methylamine (H3L) with copper(II) perchlorate. The asymmetric unit of the crystal structure of 1 contains two dinuclear units, [Cu2(H3L)2(ClO4)2]2+ and [Cu2(H3L)2(MeCN)2]4+ (abbreviated as 1ClO4 and 1MeCN), respectively, and they are linked through hydrogen bonding between the oxygen atom from the axial coordinated perchlorate anions and one of the neighboring imidazole rings from 1MeCN. EPR spectroscopic studies of 1 in MeOH by addition of bridging ligands including NaN3 and NaOH were carried out and the reaction process was discussed. 相似文献
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The paper describes a probabilistic method for transmission grid security evaluation. Power system security is the ability of the power system to withstand sudden disturbances such as short circuits. The method presented here uses event and fault trees and combines them with power system dynamic simulations. Event trees model the substation protection and trip operations after line faults. Different event tree end states (fault duration, circuit breaker trips) are simulated with power system dynamic analysis program. The dynamic analysis results (power system post-fault states) are then classified into secure, alert, emergency and system breakdown. The probabilities, minimal cut sets and grid level importance measures (Fussell-Vesely, risk increase and decrease factors) are calculated for the total and partial system breakdown. In this way, the relative importance of the substation devices regarding to the system breakdown can be reached. Also the more and less likely contributing factors to system breakdown are received. With this method, an existing 400 kV transmission grid with its line fault and device failure statistics is analysed. 相似文献
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Jorge Salinas Uber Ilpo Mutikainen Urho Turpeinen Patrick Gamez Jan Reedijk 《Inorganic chemistry communications》2007,10(12):1478-1481
Reaction of silver nitrate with the ligand 2-(1-Methyl-1H-pyrazol-5-yl)pyridine (1-mpp) produces a supramolecular material comprising three different types of one-dimensional coordination polymers as a result of two distinct orientations of the nitrate anions (with a 50/50 ratio) in the crystal lattice. 相似文献
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Kaisa Simola Urho Pulkkinen Heli Talja Pivi Karjalainen-Roikonen Arja Saarenheimo 《Reliability Engineering & System Safety》2004,84(1):65-74
This paper describes the comparative study of two approaches to estimate pipe leak and rupture frequencies for piping. One method is based on a probabilistic fracture mechanistic model while the other one is based on statistical estimation of rupture frequencies from a large database. In order to be able to compare the approaches and their results, the rupture frequencies of some selected welds have been estimated using both of these methods. This paper highlights the differences both in methods, input data, need and use of plant specific information and need of expert judgement. The study focuses on one specific degradation mechanism, namely the intergranular stress corrosion cracking. This is the major degradation mechanism in old stainless steel piping in BWR environment, and its growth is influenced by material properties, stresses and water chemistry. 相似文献
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