A note on the span of Hadamard products of vectors

We give a new proof of Theorem 6 in [L. Qiu and X. Zhan, On the span of Hadamard products of vectors, Linear Algebra Appl. 422 (2007) 304–307].     

Order Parameters of β-Substituted Anthraquinone Dyes I: 1-Amino-4-Hydroxyanthraquinone Derivatives

A study is presented of the optical order parameters and spectroscopic properties of I-amino-4-hydroxyanthraquinone derivatives containing various substituents in the 2-position in a nematic liquid crystalline mixture composed of cyanophenylcyclohexane derivatives. The results are discussed in terms of the effects of the dye structure on the order parameters. By introducing a-SCH₂-group into the 2-position, magenta dyes have been obtained which show high order parameters and solubilities. In addition, preliminary data on the solubility and photostability of the dyes are reported.     

N2O and NO2 Formation in the Disproportionation of no over Ion Exchanged Cu-ZSM-5 at Lower Temperature

NO₃-type and NO₂-type adsorbed species are formed on Cu-ZSM-5 together with adsorbed O species at 523 K in the decomposition of NO accompanied by the evolution of N2, N₂O, and NO₂. This revised version was published online in June 2006 with corrections to the Cover Date.     

Total synthesis of (-)-neplanocin a by using lithium thiolate-initiated Michael-aldol tandem cyclization reaction.

(-)-Neplanocin A (1), S-adenosylhomocystein hydrolase inhibitor, was synthesized. The characteristic of this synthesis is a stereoselective construction of five-membered ring of neplanocin A by intramolecular aldol reaction of the lithium enolate that was generated by conjugate addition of lithium thiolate. TBS-protected chiral omega-oxo-alpha,beta-unsaturated ester 16, which was prepared from D-mannitol, was treated with 1.2 equiv of lithium benzylthiolate in THF at -20 degrees C to give three separable cyclization products in good yields and stereoselectivity. After conversions of protective groups, the benzylsulfanyl part of 21 was removed by oxidation to sulfoxide and subsequent thermal elimination to give the requisite double bond. Through the functional group transformations of 30, total synthesis of (-)-neplanocin A (1) was accomplished.     

Analysis of Anionic Polymer Dispersant Behavior in Dense Silicon Nitride and Carbide Suspensions Using an AFM

The paper focuses on the interaction mechanism caused by anionic polymer dispersants in dense silicon nitride and silicon carbide suspensions. An atomic force microscope (AFM) was used to determine the relationship between the macroscopic suspension viscosity and the microscopic structure adsorbing of a polymer dispersant at the solid/liquid interface. The surface interactions within the suspensions were analyzed under various dispersant pH values and additive conditions. The addition of an anionic polymer dispersant decreased the viscosity of silicon nitride and silicon carbide suspension and increased the electrosteric repulsive force on the non-oxide surface in solution at pH > 6, which was the isoelectric point of the materials. Based on the above results, we estimated the adsorption mechanism of anionic polymer dispersants on each solid surface in solution under relatively high pH conditions.     

Numerical simulation of pool boiling of a Lennard-Jones liquid

We performed a numerical simulation of pool boiling by a molecular dynamics model. In the simulation, a liquid composed of Lennard-Jones particles in a uniform gravitational field is heated by a heat source at the bottom of the system. The model successfully reproduces the change in regimes of boiling from nucleate boiling to film boiling with the increase of the heat source temperature. We present the pool boiling curve by the model, whose general behavior is consistent with those observed in experiments of pool boiling.     

Synthesis and helical properties of N‐substituted p‐benzamide random copolymers possessing chiral/achiral and (S)/(R) side chains

Random copolymers of poly(p‐benzamide)s having a methyl‐substituted tri(ethylene glycol) unit as a chiral side chain and a nonsubstituted tri(ethylene glycol) or branching alkyl unit as an achiral side chain were synthesized by copolymerization of N‐substituted 4‐aminobenzoic acid ester monomers with a base in the presence of an initiator. Copolymerizations of the chiral (S)‐monomer with N‐tri(ethylene glycol) achiral monomer and with the racemic monomer were carried out by the addition of a mixture of two monomers and an initiator to a solution of a base all at once, affording the corresponding random copolymers. On the other hand, random copolymerization of the chiral monomer with monomer having an achiral branching alkyl side chain required dropwise addition of the achiral monomer to a mixture of the chiral monomer, the initiator, and the base. These copolymers formed helical structures, but analysis of the CD spectra indicated the absence of cooperativity between the monomer units along the copolymers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011