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University-based research centers can bring prestige and revenue to the institutions of higher education with which they are affiliated. Collaborating with corporations, units of government, and foundations, centers provide servic...
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University-based research centers can bring prestige and revenue to the institutions of higher education with which they are affiliated. Collaborating with corporations, units of government, and foundations, centers provide services to organizational leaders, policy makers, and communities. University research centers continue to increase in number and influence. Despite these increases and unique attributes of centers, center leaders are subject to cultural norms, political moves, and traditional flows of resources within their institutions. Survey and secondary data analyses of 176 educational centers confirmed and provided a ranking for characteristics associated with Ikenberry and Friedman's standard, adaptive, and shadow heuristic introduced in 1972. Interviews with 12 center directors yielded a list of center administrative issues and strategies to address issues of planning, leadership, institutional relations, funding, and management. Center and university leaders can use findings to categorize and better understand the organizational behavior of centers to improve effectiveness.
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Calculated by DFT (PBE/3z) based on the experimental crystal atom coordinates, the molecular pair (MP) interaction energies are used to analyze the crystal packing for compounds 1-6. Supplementing the visual geometric approach use...
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Calculated by DFT (PBE/3z) based on the experimental crystal atom coordinates, the molecular pair (MP) interaction energies are used to analyze the crystal packing for compounds 1-6. Supplementing the visual geometric approach used in the PLATON and MERCURY programs, the MP interaction energies make it possible to describe the crystal architecture more completely and structurally, to identify supramolecular motifs more reliably, and to determine their hierarchy.
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Molecular pair (MP) interaction energies, DFT calculated (PBE/3z) based on the experimental crystal atomic coordinates, are used to analyze the crystal packing of enaminoimine and related enaminoketones complexes with dioxane and ...
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Molecular pair (MP) interaction energies, DFT calculated (PBE/3z) based on the experimental crystal atomic coordinates, are used to analyze the crystal packing of enaminoimine and related enaminoketones complexes with dioxane and pyridine. The sign of the interaction energy of enaminoimine molecules in the chain (complex 4) and in the supermolecule (complex 5) indicates that they are held in the observed position by the intermolecular interaction with solvent. The enaminoketone molecules in complexes 6 and 7 are, on the contrary, linked by N-H center dot center dot center dot O hydrogen bonds into dimers, which interacting with solvent molecules form chains (complex 6) and supermolecules (complex 7). In addition to the visual geometrical approach of PLATON and MERCURY programs, the MP interaction energies allow a more complete and structural description of the crystal architecture, a more reliable determination of supramolecular motifs and their hierarchy.
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A series of carbamazepine cocrystals with aromatic carboxylic acids have been prepared, including (CBZ)(1)(DBA)(1), (CBZ)(2)(DBA)(1)(CH3OH)(1) (DBA = 2,3-dihydroxy benzoic acid), (CBZ)(1)(NA)(1)(H2O)(1) (NA = 1-naphthoic acid) and...
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A series of carbamazepine cocrystals with aromatic carboxylic acids have been prepared, including (CBZ)(1)(DBA)(1), (CBZ)(2)(DBA)(1)(CH3OH)(1) (DBA = 2,3-dihydroxy benzoic acid), (CBZ)(1)(NA)(1)(H2O)(1) (NA = 1-naphthoic acid) and (CBZ)(1)(AC)(1) (AC = anthracene-9-carboxylic acid). The synthons formed in CBZ cocrystals, e.g. amide center dot center dot center dot acid heterodimer, amide center dot center dot center dot amide homodimer, and amide center dot center dot center dot acid center dot center dot center dot H2O heterosynthon have been discussed and compared with synthons in reported CBZ cocrystals in CSD. The solid state properties of these cocrystals, such as transformation, solubility and their stabilities have been discussed in the article. (C) 2018 Elsevier B.V. All rights reserved.
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Design of an ultra-wideband multiple-way power divider based on the coaxial ring cavity configuration is presented. The proposed design includes increased numbers of the power divider ports, compared to the available designs, than...
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Design of an ultra-wideband multiple-way power divider based on the coaxial ring cavity configuration is presented. The proposed design includes increased numbers of the power divider ports, compared to the available designs, thanks to an incorporated coaxial power divider. For this purpose, the cavity layer in the ring cavity power divider is designed in two separate cavity rings and each ring is fed independently through an integrated coaxial power divider. Therefore, the number of the output ports is increased by 50%. A sample prototype is simulated for ultra wideband frequency range, and the performance is computed by using a full wave electromagnetic simulation technique. The power divider has 50 ports of 32 outer ring and 18 inner ring ports. The impedance bandwidth for the return loss <15 dB is obtained for the frequency range of 4-10.5 GHz. The average insertion loss, amplitude imbalance, phase imbalance, and group delay are better than 0.4 dB, +/- 0.8 dB, 12 degrees, and 0.6 ns, respectively.
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We study the center problem for planar systems with a linear center at the origin that in complex coordinates have a nonlinearity formed by the sum of two monomials. Our first result lists several centers inside this family. To th...
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We study the center problem for planar systems with a linear center at the origin that in complex coordinates have a nonlinearity formed by the sum of two monomials. Our first result lists several centers inside this family. To the best of our knowledge this list includes a new class of Darboux centers that are also persistent centers. The rest of the paper is dedicated to try to prove that the given list is exhaustive. We get several partial results that seem to indicate that this is the case. In particular, we solve the question for several general families with arbitrary high degree and for all cases of degree less or equal than 19. As a byproduct of our study we also obtain the highest known order for weak-foci of planar polynomial systems of some given degrees.
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The propensity of backbone C atoms to engage in carbon-oxygen (CH center dot center dot center dot O) hydrogen bonding is well-appreciated in protein structure, but side chain CH center dot center dot center dot O hydrogen bonding...
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The propensity of backbone C atoms to engage in carbon-oxygen (CH center dot center dot center dot O) hydrogen bonding is well-appreciated in protein structure, but side chain CH center dot center dot center dot O hydrogen bonding remains largely uncharacterized. The extent to which side chain methyl groups in proteins participate in CH center dot center dot center dot O hydrogen bonding is examined through a survey of neutron crystal structures, quantum chemistry calculations, and molecular dynamics simulations. Using these approaches, methyl groups were observed to form stabilizing CH center dot center dot center dot O hydrogen bonds within protein structure that are maintained through protein dynamics and participate in correlated motion. Collectively, these findings illustrate that side chain methyl CH center dot center dot center dot O hydrogen bonding contributes to the energetics of protein structure and folding. Proteins 2015; 83:403-410. (c) 2014 Wiley Periodicals, Inc.
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The interactions in /aromatic /pseudo- type complexes of C2H4/C2H2/C6H6/(CH2)(3)MX (M=Cu, Ag, Au; X=F, Cl, Br, I) were researched by theoretical calculation at the wB97XD/aug-cc-pVTZ level and compared with the isomorphous C2H4/C2...
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The interactions in /aromatic /pseudo- type complexes of C2H4/C2H2/C6H6/(CH2)(3)MX (M=Cu, Ag, Au; X=F, Cl, Br, I) were researched by theoretical calculation at the wB97XD/aug-cc-pVTZ level and compared with the isomorphous C2H4/C2H2/C6H6/(CH2)(3)HX/YX (X=F, Cl, Br; Y=Cl, Br) complexes. Results indicate that non-bonded interactions, namely /aromatic /pseudo-Cu/Ag/Au, contribute to the stability of the resulting dimers except for (CH2)(3)AuF. The interaction energies of C2H2/C2H4/C6H6/(CH2)(3)MX reduced with the decrease in electronegativity F>Cl>Br>I. The order is Au>Cu>Ag in C2H4/C2H2/C6H6MX complexes. The interaction energies are MX>aromatic MX>pseudo-MX>/aromatic /pseudo-HX/YX with the sequence Cu>Au>Ag. The charge transfer of most complexes is from the bonding orbital ((C-C)) of C-C bonds to antibonding orbital of MX monomers and occupied orbitals of the metal back-donation into the (CC)* antibonding orbital of the -system. (CH2)(3)AuF has the unique largest interaction energy (-89.31kcal/mol) with the charge transfer from because it formed two stable coordination bonds.
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The title compound was prepared by the condensation of an equimolar mixture of 1-(2,5-dichlorothiophen-3-yl)-3-(4-methoxyphenyl)prop-2-en-1-one, malononitrile and sodium hydroxide. The molecular structure was fully characterized u...
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The title compound was prepared by the condensation of an equimolar mixture of 1-(2,5-dichlorothiophen-3-yl)-3-(4-methoxyphenyl)prop-2-en-1-one, malononitrile and sodium hydroxide. The molecular structure was fully characterized using different spectroscopic methods. Mass ESI-HRMS measurements were performed. The HRESIMS analysis revealed the molecular formula, C18H12Cl2N2O2SNa, with [M + Na](+) and [M + Na + 2](+) and [M + Na + 4](+) isotopic clusters characteristic for a dichlorinated compound. The compound was also thoroughly characterized by H-1, C-13, NMR spectra and 2D NMR spectra (COSY, HSQC and HMBC). The molecular structure was confirmed by X-ray single crystal analysis. The new compound crystallizes in the orthorhombic, Pbcn space group with unit cell dimensions: a = 31.901(7) , b = 15.412(4) , c = 7.3655(14) , V = 3621.3(13) (3) and Z = 8. In the title compound, the central pyridine ring carries four substituents, a thiophene ring, a methoxyphenyl ring, a carbonitrile group and a methoxy group. The dihedral angles between the planes of the pyridine ring, the thiophene ring and the methoxyphenyl ring are 36.66 and 40.18A degrees, respectively. Intermolecular C-H center dot center dot center dot O/N, pi center dot center dot center dot pi and anion center dot center dot center dot pi [Cl center dot center dot center dot pi] interactions are found in the crystal structure. All interactions consolidate a three dimensional network.
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In this paper we study a family of quartic linear-like reversible polynomial systems having a nondegenerate center at the origin. This family has degree one with respect to one of the variables. We are interested in systems in thi...
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In this paper we study a family of quartic linear-like reversible polynomial systems having a nondegenerate center at the origin. This family has degree one with respect to one of the variables. We are interested in systems in this class having two extra nondegenerate centers outside the straight line of symmetry. The geometrical configuration of these centers is aligned or triangular. We solve the center problem in both situations and, in the second case, we study the limit cycles obtained from a simultaneous degenerate Hopf bifurcation in the quartic polynomials class. (C) 2019 Elsevier Ltd. All rights reserved.
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