Evidence for Spin-Singlet Superconductivity in Layered MgB2
This paper has been withdrawn by the authors, because of serious experimental problems.
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Catalytic synthesis and photoluminescence of β-Ga2O3 nanowires
Monoclinic gallium oxide (β-Ga2O3) nanowires were synthesized by heat treating a composite material of GaAs and pre-evaporated Au at 1240 °C in dry oxygen atmosphere. The catalytic Au metal generated liquid nanoclusters that serve as reactive sites confining and directing the growth of β-Ga2O3 nanowires during the vap…
Density functional theory of a Gay—Berne film between aligning walls
It is shown that the simple Onsager second-virial approximation of density functional theory can successfully describe the orientational structure of a Gay-Berne film confined between aligning plates. The theory takes as input the density profile as determined by computer simulation and semi-quantitatively reproduces…
Characterization and control of a multielement dual-frequency liquid-crystal device for high-speed adaptive optical wave-front correction
Multielement nematic liquid-crystal devices have been used by others and ourselves for closed-loop adaptive control of optical wave-front distortions. Until recently the phase retardance of available devices could be controlled rapidly in only one direction. The phase retardance of the dual-frequency device can be con…
Evidence of Oxygen Intercalation and Mobility at Room Temperature in Oxides: An Electrochemical Quartz Microbalance Study of Intercalation in La2CuO4
This paper offers direct evidence for the electrochemical intercalation of oxygen in an oxide with the K 2 NiF 4 structure, namely, La 2 CuO 4, at room temperature. Organic solvents, as well as water, allow that reaction to occur. The charge-to-mass ratio evaluated from a comparison with fluoride intercalation implies…
Structurally Homologous β- and meso-Amidinium Porphyrins
A synthetic strategy has been developed to afford porphyrins site-derivatized with the same hydrogen-bond synthon attached directly to the macrocyclic ring. Porphyrin homologues derivatized at the β and meso positions with an amidinium group form 1:1 supramolecular complexes with benzoate acceptors and show notable di…
Metal- and Ligand-Centered Monoelectronic Oxidation of μ-Nitrido[((tetraphenylporphyrinato)manganese)(phthalocyaninatoiron)], [(TPP)Mn−N−FePc]. X-ray Crystal Structure of the Fe(IV)-Containing Species [(THF)(TPP)Mn−N−FePc(H2O)](I5)·2THF
The reaction of mu-nitrido[((tetraphenylporphyrinato)manganese)(phthalocyaninatoiron)], [(TPP)Mn-N-FePc], with I(2) in THF develops with the formation of two different species, i.e., [(THF)(TPP)Mn-N-FePc(H(2)O)](I(5)).2THF (I) and [(TPP)Mn(IV)-N-Fe(III)Pc](I(3)) (II). On the basis of single-crystal X-ray work and Möss…
Oxidation State Dependence of the Geometry, Electronic Structure, and Magnetic Coupling in Mixed Oxo- and Carboxylato-Bridged Manganese Dimers
Approximate density functional theory has been used to investigate changes in the geometry and electronic structure of the mixed oxo- and carboxylato-bridged dimers [Mn(2)(mu-O)(2)(O(2)CH)(NH(3))(6)](n+)and [Mn(2)(mu-O)(O(2)CH)(2)(NH(3))(6)](n+)in the Mn(IV)Mn(IV), Mn(III)Mn(IV), and Mn(III)Mn(III) oxidation states. T…
A Novel Azido and Pyrazine-Dioxide Bridged Three-Dimensional Manganese(II) Network with Antiferromagnetic Ordering (TN = 62 K) and a Spin Flop State
A novel three-dimensional network, Mn(N3)2(pzdo), bridged by azido and pzdo (pzdo = pyrazine−dioxide) has been synthesized and structurally and magnetically characterized. It possesses a cubic-like structure and shows an antiferromagnetic ordering at higher temperature (62 K) and a spin−flop transition.
High Li+-Ion Storage Capacity and Double-Electrochromic Behavior of Sol−Gel-Derived Iron Oxide Thin Films with Sulfate Residues
FeSO 4 ·7H 2 O was precipitated with ammonia solution in the presence of H 2 O 2 as an oxidant. The precipitate was washed slightly with deionized water and then peptized with acetic acid (ca. 60 mol %) to attain a homogeneous sol. Iron oxide films were fabricated by spin-coating the sol onto ITO-coated glass substrat…
Functionalizing Polymer Surfaces by Field-Induced Migration of Copolymer Additives. 1. Role of Surface Energy Gradients
Field-induced migration of low surface tension polystyrene- b -poly(dimethyl siloxane) (PS- b -PDMS) block copolymer additives in a polystyrene (PS) host was investigated using a series of narrow molecular weight distribution polystyrenes (5 × 10 3 < M w,PS < 2 × 10 7 g/mol). Dynamic contact angle analysis (DCA) and a…
Synthesis of Homoleptic Gallium Alkoxide Complexes and the Chemical Vapor Deposition of Gallium Oxide Films
A general synthetic route to gallium alkoxide complexes involving reactions of gallium tris(dimethylamide) with alcohols was developed and gallium oxide films were prepared by using a gallium alkoxide complex as the precursor in a chemical vapor deposition process. The complex [Ga(NMe 2 ) 3 ] 2 reacted with i -BuOH an…
Photochemical Control of the Macrostructure of Cholesteric Liquid Crystals by Means of Photoisomerization of Chiral Azobenzene Molecules
Chiral azobenzene compounds were prepared. A cholesteric phase was induced by mixing each azobenzene compound in a host nematic liquid crystal. A twisting power of the chiral azobenzene compounds was dependent on the distance between an azobenzene moiety and chiral moiety. The twisting power of the chiral azobenzene c…
Effect of Colloidal Fillers on the Cross-Linking of a UV-Curable Polymer: Gel Point Rheology and the Winter−Chambon Criterion
The effect of colloidal silica fillers on the cross-linking behavior of a model UV-curable polymer system (thiol−ene) is studied using in situ rheology and real-time FTIR spectroscopy. The validity of the Winter−Chambon criterion (convergence of the loss tangents at the gel point) is examined for the cross-linking of…
Strong Cooperativeness in the Mononuclear Iron(II) Derivative Exhibiting an Abrupt Spin Transition above 400 K
The spin crossover system, [Fe(bzimpy)(2)](ClO(4))(2).0.25H(2)O, was reinvestigated above room temperature (bzimpy = 2,6-bis(benzimidazol-2-yl)pyridine). The system exhibits an abrupt low-spin to high-spin transition at T(c) = 403 K. Liberation of a fractional amount of water does not affect the spin crossover: the sy…
Synthesis of Thiolate-Stabilized Platinum Nanoparticles in Protolytic Solvents as Isolable Colloids
Water-dispersible, isolable thiolate-stabilized platinum nanoparticles are synthesized by two one-phase methods: one is conducted in water; another mainly in methanol, through the reduction of chloroplatinic acid with sodium borohydride, using mercaptosuccinic acid (MSA) as the stabilizer. The well-separated particles…
Carbon Nanotubes as a Superior Sorbent for Nitrogen Oxides
Carbon nanotubes were prepared and investigated as sorbents for NO, SO 2, and CO 2 in the presence of O 2 . The preliminary results indicate that they are a good and reversible sorbent for NO removal at room temperature. An uptake amount of 78 mg/g of NO x was obtained by TGA when the carbon nanotubes were exposed to…
Predicting Controlled-Release Behavior of Degradable PLA-b-PEG-b-PLA Hydrogels
This paper describes the development and application of scaling laws relating bulk-degradation behavior of poly(lactic acid)−poly(ethylene glycol)−poly(lactic acid) (PLA- b -PEG- b -PLA) copolymer hydrogels to the ever-changing transport properties during network degradation. Specifically, the relationships developed…
A Spectroscopic Analysis of Poly(lactic acid) Structure
A vibrational analysis has been carried out to analyze the chain conformation of poly(lactic acid) in the crystalline state. In conjunction with a normal-coordinate analysis, the Raman spectrum has yielded data regarding conformational distributions. Raman spectra of different helices were simulated using previously p…
Small-Angle X-ray Scattering of Polymers
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSmall-Angle X-ray Scattering of PolymersBenjamin Chu and Benjamin S. HsiaoView Author Information Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794-3400 Cite this: Chem. Rev. 2001, 101, 6, 1727–1762Publication Date (Web):May 19…