Materials Literature
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It is shown in this paper that the wetting behavior of n-alkanes on a water surface can be predicted using the wetting theory of Cahn, together with experimental results for n-alkane vapor adsorption on water which are readily available in the literature. The evolution of the wetting behavior with the carbon number of…
Structural relaxation in viscous glycerol has been followed from 5.9 ps to 3.7 ns by coherent neutron scattering around the structure factor maximum. In a 100 K interval, the line shape of the decay function shows no significant temperature dependence; the mean relaxation time scales accurately with viscosity. Interpa…
The anomalies of supercooled water in thermodynamic response functions at atmospheric pressure, the phase transition between low and high density amorphous ices (LDA and HDA), and a predicted fragile–strong transition are accounted for in a unified manner by reconciling an idea due to Stanley and co-workers introducin…
噴出起源の異なる幾つかの北海道粗粒火山灰土について, 排水・非排水三軸圧縮, 平面ひずみ圧縮及び繰返し非排水せん断試験を実施し, それらの力学特性を調べた. 一連の実験と考察から, 1) せん断中に有効平均主応力が増加するような応力条件では構成粒子の破砕が確実にもたらされるものの, 繰返し非排水せん断過程で液状化に向かうような場合は粒子破砕はほとんど生じない, 2) 破砕性の卓越する火山灰土の応力―ひずみ―強度特性は有効拘束圧 (あるいは平均主応力) に強く依存するとともに, 通常の密度の砂ではみられない特異なダイレイタンシー挙動を示す, 3) 降下生成物で構成されている火山灰地盤の静的・動的力学特性にはクリーンな砂よりもはるかに…
Metal–porphyrin π bonds such as those in 1 and 2 were hitherto unknown modes of coordination in porphyrin complexes. However, arene complexes of this kind were recently synthesized by Rauchfuss et al. (Angew. Chem. Int. Ed. Engl. 1996, 35, 1833). Metal – porphyrin interactions of this type may also play a role in reac…
In only a few picoseconds the photoinduced electron transfer in the noncovalently linked complex between zinc porphyrin 1 and the quinone 2 is complete. Transient absorption spectra show the zinc porphyrin cation radical as typical intermediate of the electron transfer.
Trivacant polyoxotungstates such as α-A-[PW9O34]9− ions react with tBuSiCl3 to afford the anion 1. This can react further with other trichlorosilanes to give α-A-[PW9O34(tBuSiO)3(RSi)]3− ions (R = H, Me, Et, CHCH2, CH2CH2CH2Cl). Similar arsenic compounds are also reported.
Many liquids with vastly different properties can form glasses upon cooling. Although this phenomenon has been known since ancient times, no complete general understanding of the glass transition is available. In his Perspective, Sokolov reviews recent theoretical and experimental progress in unraveling the mysteries…
Fine tuning of the magnetic properties can be achieved in [Ni(tren)]3[Fe(CN)6]2·6 H2O (1, section of structure shown on the right; tren = tris(2-aminoethyl)amine), the first example of a three-dimensional bimetallic network of a Prussian blue analogue containing organic groups. The compound orders as a bulk ferrimagn…
Broad-band dielectric spectroscopy (10 −2 Hz–10 7 Hz) is employed to study the molecular dynamics of three low-molecular-weight glass-forming H-bonded liquids being confined in (dielectrically inactive) porous glasses with pore sizes of 2.5 nm, 5.0 nm and 7.5 nm. From the relaxation time distribution of the dielectric…
Zinc porphyrin/pyridine coordination interactions have been used to assemble complexes containing two different chromophore arrays. These undergo photoinduced electron transfer (see picture) and energy transfer reactions, which mimic some of the primary events in photosynthesis.
In the framework of a recently reported linear-scaling method for density-functional-pseudopotential calculations, we investigate the use of localized basis functions for such work. We propose a basis set in which each local orbital is represented in terms of an array of `blip functions'' on the points of a grid. We a…
Between 2 and 44 gL−1 of the diamide 1 are necessary to obtain stable gels with a wide variety of organic solvents. The circular dichroism of the gels can be attributed to the formation of chiral aggregates from 1, which are held together by hydrogen bonds and van der Waals interactions.
Poly(styrene) was grafted onto silk fibers in an aqueous medium, using ammonium persulphate initiator. Add-ons of up to 100% were achieved. The add-on increased linearly with the monomer concentration of the grafting system, all other factors remaining constant. The yield of the reaction attained about 80% and the ext…
Water-soluble chitosan with a 50% deacetylation degree was prepared according to the literature. The mixtures of water-soluble chitosan and poly(acrylic acid) (PAA) in water was studied by various experimental techniques, such as viscometry, potentiometry, and transmittance measurements. The results showed that water-…
Damping properties of epoxy resin/polyurethane (EP/PU) semi-interpenetrating polymer networks (IPNs) were studied by the dynamic mechanical analysis (DMA) method. It shows that the semi-IPNs have excellent damping properties at ordinary temperature. The maximum value of tan δ is about 1 when the weight composition of…
This study reports the use of texture profile analysis (TPA) to mechanically characterize polymeric, pharmaceutical semisolids containing at least one bioadhesive polymer and to determine interactions between formulation components. The hardness, adhesiveness, force per unit time required for compression (compressibil…
In this paper we apply variational energy band theory to a form of the Holstein Hamiltonian in which the influence of lattice vibrations (optical phonons) on both local site energies (local coupling) and transfers of electronic excitations between neighboring sites (nonlocal coupling) is taken into account. A flexible…
The complexes [PtR(dppm- P,P )(dppm- P )]PF 6 (R = Me, Et, Ph) react with [AuCl(SMe 2 )] to generate the dppm-bridged platinum−gold complexes trans -[PtClR(μ-dppm) 2 Au]PF 6 ( 1 ). Addition of [PtR(dppm- P,P )(dppm- P )]Cl to a solution of silver(I) acetate, followed by acetyl chloride, yields the neutral platinum-sil…
Molecular dynamics simulations of the oligonucleotide duplex d(CGCGCG)2 in aqueous solution are used to investigate the glass transition phenomenon. The simulations were performed at temperatures in the 20 K to 340 K range. The mean square atomic fluctuations showed that the behavior of the oligonucleotide duplex was…