14,526 research outputs found
The Takayama and Judge Price and Allocation Models and its application in non-linear Price Transmission Analysis Approaches
Demand and Price Analysis, Research Methods/ Statistical Methods, C15, C18, C62,
[my]-Bis(diphenylphosphanyl)borato-[kappa]2P:P'-bis[dicarbonyl([eta]5-cyclopentadienyl)iron(II)] tetrachloridoferrate(III) chloroform solvate
The title compound, [Fe2(C5H5)2(C24H22BP2)(CO)4][FeCl4]·CHCl3, is an oxidation product of CpFe(CO)2PPh2BH3. One pair of phenyl rings attached to the two different P atoms are almost parallel, as are the other pair [dihedral angles = 8.7 (5) and 8.9 (5)°]. The planes of the two cyclopentadienyl rings are inclined by 26.8 (7)° with respect to each other. The carbonyl groups at each Fe atom are almost perpendicular [C-Fe-C = 92.6 (6) and 94.3 (5)°]. Key indicators: single-crystal X-ray study; T = 173 K; mean σ(C–C) = 0.019 Å; R factor = 0.112; wR factor = 0.177; data-to-parameter ratio = 16.8
Adenosinium 3,5-dinitrosalicylate
The crystal structure of adenosinium 3,5-dinitrosalicylicate, C10H14N5O4+烷H3N2O7-, shows the presence of a primary chain structure formed through homomeric head-to-tail cyclic R22(10) hydrogen-bonding interactions between hydroxy O- and both purine and amine N-donor and acceptor groups of the furanose and purine moieties of the adenosinium species. These chain structures are related by crystallographic 21 symmetry. Secondary hetero-ionic hydrogen bonding, involving the 3,5-dinitrosalicylate anion, including a cyclic R22(8) interaction between the carboxylate group and the protonated purine and amine groups of the adenosinium cation are also present, together with heteromolecular - interactions giving a three-dimensional hydrogen-bonded polymer structure.Full Tex
Hydrogen-bonding synthons in lamotrigine salts: 3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazin-2-ium 2-[(2-carboxyphenyl)disulfanyl]benzoate in its monohydrate and anhydrous forms
Lamotrigine is a drug used in the treatment of epilepsy and related convulsive diseases. The drug in its free form is rather inadequate for pharmacological use due to poor absorption by the patient, which limits its bioavailability. On the other hand, the lamotrigine molecule is an excellent hydrogen-bonding agent and this has been exploited intensively in the search for better formulations. The formulation presently commercialized (under the brand name Lamictal) is rather complex and includes a number of anions in addition to the active pharmaceutical ingredient (API). The title salts of lamotrigine, namely 3,5-diamino-6-(2,3-dichlorophenyl)-1,2,4-triazin-2-ium 2-[(2-carboxyphenyl)disulfanyl]benzoate monohydrate, C9H8Cl2N5+·C14H9O4S2-·H2O, (I), and the anhydrate, C9H8Cl2N5+·C14H9O4S2-, (II), contain a lamotriginium cation (L), a hydrogen dithiodibenzoate monoanion (D) and, in the case of (I), a disordered solvent water molecule. Both L and D present their usual configurations severely twisted around their central C-C and S-S bonds, respectively. The supramolecular structure generated by the many available donor and acceptor sites is characterized by a planar antisymmetric motif of the form D-L-L-D, i.e. the structural building block. Although this characteristic motif is extremely similar in both structures, its conformation involves different donors and acceptors in its R22(8) central L-L homosynthon. The lateral R22(8) D-L heterosynthons are, on the other hand, identical. These substructures are further connected by strong hydrogen bonds into broad two-dimensional structures, in turn weakly linked to each other. Even if the homo- and heterosynthons in (I) and (II) are rather frequent in lamotrigine structural chemistry, the composite tetrameric synthon appears to be much less common. The occurrence of these motifs among lamotrigine salts and cocrystals is analyzed.Fil: Freire Espeleta, Eleonora. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Polla, Griselda Ines. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: Baggio, Ricardo Fortunato. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; Argentin
Tetraacetonitrilelithium tetraisothiocyanatoborate
The crystal structure of the title salt, [Li(CH3CN)4][B(NCS)4], is composed of discrete cations and anions. Both the Li and B atoms show a tetrahedral coordination by four equal ligands. The acetonitrile and isothiocyanate ligands are linear. The bond angles at the B atom are close to the ideal tetrahedral value [108.92 (18)–109.94 (16)°], but the bond angles at the Li atom show larger deviations [106.15 (17)–113.70 (17)°]
C62
C62 merupakan hasil pengecekan similaritas paper berjudul “Efek multilayer cu(1)/ni(1)/cu(2)/ni(2) terhadap kinerja sensor suhurendah ln2
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Case-based analysis in user requirements modelling for knowledge construction
Context: Learning can be regarded as knowledge construction in which prior knowledge and experience
serve as basis for the learners to expand their knowledge base. Such a process of knowledge construction
has to take place continuously in order to enhance the learners’ competence in a competitive working
environment. As the information consumers, the individual users demand personalised information provision
which meets their own specific purposes, goals, and expectations.
Objectives: The current methods in requirements engineering are capable of modelling the common
user’s behaviour in the domain of knowledge construction. The users’ requirements can be represented
as a case in the defined structure which can be reasoned to enable the requirements analysis. Such analysis
needs to be enhanced so that personalised information provision can be tackled and modelled. However,
there is a lack of suitable modelling methods to achieve this end. This paper presents a new
ontological method for capturing individual user’s requirements and transforming the requirements onto
personalised information provision specifications. Hence the right information can be provided to the
right user for the right purpose.
Method: An experiment was conducted based on the qualitative method. A medium size of group of users
participated to validate the method and its techniques, i.e. articulates, maps, configures, and learning content.
The results were used as the feedback for the improvement.
Result: The research work has produced an ontology model with a set of techniques which support the
functions for profiling user’s requirements, reasoning requirements patterns, generating workflow from
norms, and formulating information provision specifications.
Conclusion: The current requirements engineering approaches provide the methodical capability for
developing solutions. Our research outcome, i.e. the ontology model with the techniques, can further
enhance the RE approaches for modelling the individual user’s needs and discovering the user’s
requirements
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