Materials Literature
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Selective synthesis of particles of angstrom to nanometer size consisting of one to many metal atoms is instrumental in various applications, but it has been hampered by the tendency of the metal atom to form large clusters. We found, as studied by the state-of-the-art electron microscopic technique, a strategy to pro…
Gold nanoparticles stabilized by thiol-terminated poly(ethylene glycol) monomethyl ethers with molecular weights ranging from 350 to 2000 have been prepared at thiol-to-gold molar ratios ranging from 3:1 to 1:8. Particle size distributions have been constructed for these particles from transmission electron microscopy…
Abstract Scale inhibitors (SI) have been applied very successfully over many years in oilfields to prevent the formation of mineral scale. Both barium sulphate and calcium carbonate scales may be prevented using inhibitors, although in this work we will focus on the more difficult barite inhibition problem. A number o…
CdS/polystyrene nanocomposite hollow spheres with diameters between 240 and 500 nm were synthesized under ambient conditions by a novel microemulsion method in which the polymerization of styrene and the formation of CdS nanoparticles were initiated by gamma-irradiation. The product was characterized by transmission e…
We have used scanning tunneling microscopy to identify individual phosphorus dopant atoms near the clean silicon (100)-(2x1) reconstructed surface. The charge-induced band bending signature associated with the dopants shows up as an enhancement in both filled and empty states and is consistent with the appearance of n…
We find there are at least two different steady states for transport across noncollinear magnetic multilayers. In the conventional one there is a discontinuity in the spin current across the interfaces which has been identified as the source of current induced magnetic reversal; in the one advocated herein the spin to…
We show that the transverse components of spin current in a ferromagnet is linked to an off diagonal spin component of the transmission matrix at interfaces;it has little to do with the mismatch of band structures between dissimilar metals. When we take account of this component,not considered in prior analyses, we fi…
There are at least two different putative steady state solutions for current across noncollinear magnetic multilayers; one has a discontinuity in the spin current at the interface the other is continuous. We compare the resistance of the two and find the solution with the continuous spin currents is lower. By using th…
We show that when one drives a charge current across noncollinear magnetic layers the two electron Coulomb scattering creates a spin flip potential at interfaces. This scattering is found when the interface potential is updated due to the spin accumulation attendant to charge flow, and it contributes in linear respons…
Using the recently developed version of the GW method employing the one-site approximation and self-consistent quasiparticle basis set we calculated the electronic structure of 3d and 4d transition metals at experimental atomic volumes. The results are compared with traditional local density approach and with experime…
In a recent paper, cond-mat/0404041, J. Vanacken et al. reported experimental studies of crystals of Mn12-ac molecular nanomagnets in pulsed magnetic fields with sweep rates up to 4000 T/s. Steps in the magnetization curve were observed. The data were explained by collective dipolar relaxation. We give here an alterna…
Strong tube−tube van der Waal attractions that hinder the dissolution of single walled carbon nanotubes (SWNTs) as individuals have been overcome by the direct protonation of the tubes by superacids. The pristine nanotubes disperse as individuals in 100% H 2 SO 4, oleum, trifluromethanesulfonic acid, and chlorosulfoni…
Using a thin film of metallic tin as catalyst, ultrasmall single-crystalline zinc oxide nanobelts have been synthesized in large quantity using a simple solid−vapor technique. The nanobelts have an average width of 5.5 nm and a narrow size distribution of ±1.5 nm. The nanobelts grew along the [0001] direction, with (2…
We investigated physicochemical properties of two types of poly(N-isopropylacrylamide) (PIPAAm)-grafted tissue culture polystyrene (TCPS) surfaces, to elucidate the influential factors for thermally regulated cell adhesion and detachment to PIPAAm-grafted surfaces. The two types of PIPAAm-grafted surfaces were prepare…
Using the silicon bulk micromachining and selectively oxidized porous silicon (SOPS) technology, a silicon dioxide microlens was implemented on thick oxidized porous silicon (OPS) membrane. Because the surface of microlens was the interface of OPS-Si, the surface roughness of lens was directly affected by the anodizat…
Electric field induced second harmonic generation (EFISHG) is a standard technique for the experimental determination of molecular hyperpolarizability. We have developed a novel cell design for EFISHG experiments that makes use of a conventional spectrometer glass cuvette. An efficient and convenient protocol is devel…
Abstract: Ecdysteroid is one of the two most important insect hormones, which controls growth and developmental activities of insect. In silkworm, Bombyx mori L., basically ecdysteroid induces molting and metamorphosis in larvae and exogenous administration hastens the silk synthetic activity and cocoon spinning proce…
The segmental and local dynamics of semicrystalline, melt-miscible blends of poly(ethylene oxide) [PEO] and a poly(styrene- co - p -hydroxystyrene) copolymer [SHS] were investigated using dielectric relaxation spectroscopy (DRS). A broad, yet well-defined, DRS segmental process is observed for the 5 wt % SHS blend, an…
The pga gene of Escherichia coli W ATCC11105 encodes a penicillin G acylase whose expression is regulated at both the transcriptional and post-transcriptional level. In this work we have shown that PaaX is the repressor of pga expression, and we have identified its binding consensus as TGATTC(N27)GAATCA. We conclude t…
Abstract Dynamic mechanical results are reported for segmental relaxation of monodisperse polystyrenes (PSs) with molecular weights of 0.7, 3, 18, and 104 kg/mol and bidisperse PSs created from blending pairs of these materials. The data for the monodisperse polymers confirm previous findings; namely, there is an incr…