2,802 research outputs found
Hydration of Kr(aq) in dilute and concentrated solutions
Molecular dynamics simulations of water with both multi-Kr and single Kr
atomic solutes are carried out to implement quasi-chemical theory evaluation of
the hydration free energy of Kr(aq). This approach obtains free energy
differences reflecting Kr-Kr interactions at higher concentrations. Those
differences are negative changes in hydration free energies with increasing
concentrations at constant pressure. The changes are due to a slight reduction
of packing contributions in the higher concentration case. The observed Kr-Kr
distributions, analyzed with the extrapolation procedure of Kr\"{u}ger,
\emph{et al.}, yield a modestly attractive osmotic second virial coefficient,
/mol. The thermodynamic analysis interconnecting
these two approaches shows that they are closely consistent with each other,
providing support for both.Comment: 6 pages, 7 figures. Revision follows the extrapolation procedure of
Refs. 33 and 34 which works nicely. The thermodynamic results are now clearly
consistent. The extrapolation of the Fourier transform was
not was satisfactor
Test Experiment for Time-Reversal Symmetry Breaking Superconductivity
A new experiment is proposed to probe the time-reversal symmetry of a
superconductor. It is shown that a time-reversal symmetry breaking
superconductor can be identified by the observation of a fractional flux in
connection with a Josephson junction in a special geometry.Comment: 4 pages, 2 figures available upon request, Revtex, MIT-CMT-OC
HAEMOGRAM OF NIGERIAN MONGREL BITCH AT DIFFERENT STAGES OF THE REPRODUCTIVE CYCLE
The haematologic parameters of the Nigerian Mongrel bitch were investigated at different stages of the reproductive cycle to determine their clinical values. Results showed that red blood cell (RBC) counts were highest during anoestrus, with a mean of 5.09 0.62 x 106/µL, while lowest values were recorded during pregnancy, the difference was significant (P<0.05). White blood cell (WBC) counts, packed cell volume (PCV) and haemoglobin concentration (Hb) showed an increasing pattern from anoestrus to proestrus and then decreased with transition from proestrus to oestrus. Total WBC counts were highest during dioestrus and almost twice the value recorded in pregnancy. It appears that WBC count may be used for pregnancy diagnosis in the Nigerian Mongrel bitch
Phenomenological BCS theory of the high- cuprates
A BCS model characterized by a phenomenological pair potential with on-site
(), nearest (), and next nearest () neighbour coupling
constants, and an empirical quasiparticle dispersion taken from angle-resolved
photoemission spectra is considered. The model can consistently explain the
experimental data concerning the pair state of the hole doped cuprates. Three
ingredients are required to make the interpretation possible: the existence of
flat bands, a very small effective on-site repulsion, and a slightly dominating
effective nnn attraction of the order of 60-80meV with a ratio .Comment: 13 pages, uuencoded Postscrip
Slab Effects on Beam-Column Subassemblies - Beam Strength and Elongation Issues
This paper describes the effect of composite slabs in increasing beam strength and its implications for design. It also discusses the “beam-growth” phenomena, which can detrimentally influence the performance of a frame with reinforced concrete or precast concrete beams, and its impact on steel beams with RC slabs. From the subassembly testing conducted the slab increased the beam strength by around 40%. However the slab could not maintain strength at large drifts without degradation with transverse or longitudinal decking placed around the columns. This indicates that while transverse or longitudinal slabs should not be considered in design to size the beam, they should be considered in the beam overstrength calculations for the design of other members. Also, both rational considerations and experimental results
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indicate that beam growth effects tend to be small for composite steel beams because the steel beams are able to yield in both tension and compression
Morphological evolution of lamellar forming polystyrene-block-poly(4-vinylpyridine) copolymer under solvent annealing
In this work, we are reporting a very simple and efficient method to form lamellar structures of symmetric polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) copolymer thin films with vertically (to the surface plane) orientated lamellae using a solvent annealing approach. The methodology does not require any brush chemistry to engineer a neutral surface and it is the block neutral nature of the film-solvent vapour interface that defines the orientation of the lamellae. The microphase separated structure of two different molecular weight lamellar forming PS-block-P4VP copolymers formed under solvent vapour annealing was monitored using atomic force microscopy (AFM) so as to understand the morphological changes of the films upon different solvent exposure. In particular, the morphology changes from micellar structures to well-defined microphase separated arrangements. The choice of solvent/s (single and dual solvent exposure) and the solvent annealing conditions (temperature, time etc.) has important effects on structural transitions of the films and it was found that a block neutral solvent was required to realize vertically aligned P4VP lamellae. The results of the structural variation of the phase separated nanostructured films through the exposure to ethanol are also described
Orthorhombically Mixed s and d Wave Superconductivity and Josephson Tunneling
The effect of orthorhombicity on Josephson tunneling in high T
superconductors such as YBCO is studied for both single crystals and highly
twinned crystals. It is shown that experiments on highly twinned crystals
experimentally determine the symmetry of the superconducting twin boundaries
(which can be either even or odd with respect to a reflection in the twinning
plane). Conversely, Josephson experiments on highly twinned crystals can not
experimentally determine whether the superconductivity is predominantly
-wave or predominantly -wave. The direct experimental determination of
the order-parameter symmetry by Josephson tunneling in YBCO thus comes from the
relatively few experiments which have been carried out on untwinned single
crystals.Comment: 5 pages, RevTeX file, 1 figure available on request
([email protected]
Formation of sub-7 nm feature size PS-b-P4VP block copolymer structures by solvent vapour process
The nanometer range structure produced by thin films of diblock copolymers makes them a great of interest as templates for the microelectronics industry. We investigated the effect of annealing solvents and/or mixture of the solvents in case of symmetric Poly (styrene-block-4vinylpyridine) (PS-b-P4VP) diblock copolymer to get the desired line patterns. In this paper, we used different molecular weights PS-b-P4VP to demonstrate the scalability of such high χ BCP system which requires precise fine-tuning of interfacial energies achieved by surface treatment and that improves the wetting property, ordering, and minimizes defect densities. Bare Silicon Substrates were also modified with polystyrene brush and ethylene glycol self-assembled monolayer in a simple quick reproducible way. Also, a novel and simple in situ hard mask technique was used to generate sub-7nm Iron oxide nanowires with a high aspect ratio on Silicon substrate, which can be used to develop silicon nanowires post pattern transfer
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