Solute distribution coupled with laminar flow in wide-bore capillaries: what can be separated without chemical or physical fields?

Solute diffusion coupled with an orthogonal laminar flow has been systematically studied with wide-bore capillaries to establish its limitations and reveal its potentials as separation methodology requiring neither chemical nor physical interactions. Simulations based on the advection-diffusion equation in a cylindrical coordinate system indicate several important features of this potentially useful method: (1) if a solute diffuses over the entire cross-section of the capillary before it is eluted from the capillary, it behaves as a diffusive solute and gives a Gaussian-shaped peak (diffusion peak) having an apex at the traveling time of the average flow; (2) when a solute is poorly (or not) diffusive, a new peak appears with an apex at the elution time of the maximum flow (non-diffusion peak); (3) these two peaks are simultaneously detected for intermediately diffusive solutes; (4) the transformation from the diffusion to non-diffusion peak occurs when the solute diffuses over the distance 0.86 times as large as the capillary radius before it leaves the capillary. These results of simulations are consistent with experimental results for selected solutes having various diffusivities. This method has proved useful particularly for the evaluation of diffusion coefficients of poorly diffusive solutes. Separation of PS particles having different sizes is also attempted.     

Highly luminescent nanocrystal quantum dots fabricated by lattice-type mismatched epitaxy

Lattice-type mismatched heteroepitaxy is demonstrated as a novel concept for the fabrication of almost ideal, highly luminescent nanocrystal quantum dots that are coherently embedded in a single-crystalline matrix. In this approach, the formation of quantum dots is induced by transformation of a metastable epitaxial 2D quantum well into an array of isolated nanocrystals with-highly symmetric shape. This process is driven by the lattice-type mismatch between the constituent materials and the resulting miscibility gap. The investigated PbTe/CdTe heterosystem has a model character because it combines two compounds with different cubic lattice types but almost identical lattice constants. The obtained epitaxial nanocrystals exhibit outstanding properties such as a well-defined symmetric shape, the absence of strain, intermixing and a wetting layer, which is in contrast to the conventional Stranski–Krastanow quantum dots. The small-rhomboedric-cubo-octahedron PbTe/CdTe nanocrystals on GaAs substrates display intense room temperature mid-infrared luminescence as is crucial for device applications. Ab initio density functional theory is used to clarify the interface structure, indicating that the covalent and ionic bonding character of CdTe and PbTe is maintained across the interface.     

Extremal self-dual codes of length 64 through neighbors and covering radii

We construct extremal singly even self-dual [64,32,12] codes with weight enumerators which were not known to be attainable. In particular, we find some codes whose shadows have minimum weight 12. By considering their doubly even neighbors, extremal doubly even self-dual [64,32,12] codes with covering radius 12 are constructed for the first time.     

The pion velocity at chiral restoration and the vector manifestation

We study the effects of Lorentz non-invariance on the physical pion velocity at the critical temperature T_c in an effective theory of hidden local symmetry (HLS) with the “vector manifestation” fixed point. We match at a “matching scale” Λ_M the axial-vector current correlator in the HLS with the one in the operator product expansion for QCD, and present the matching condition to determine the bare pion velocity. We find that the physical pion velocity, which is found to be one at T=T_c when starting from the Lorentz invariant bare HLS, remains close to one with the Lorentz non-invariance, v_π(T_c)=0.83–0.99. This result is quite similar to the pion velocity in dense matter.     

Influence of the loading rate on liquid‐crystalline epoxy resin systems

The fracture toughness of liquid‐crystalline epoxy systems, which had a nematic polydomain structure (domain size about 40 μm), with an increasing loading rate was evaluated. In this system, the fracture toughness dramatically decreased from 1.96 to 0.22 MN/m^3/2 with an increasing loading rate (0.1–5 mm/min). The network orientation near the fracture surface of different loading rate systems was investigated with polarized optical microscopy and polarized infrared spectroscopy. As a result, a large oriented region of mesogenic groups was observed near the fracture surface in the relatively low loading rate (0.1 and 0.5 mm/min) systems, but such a phenomenon was not observed in the high loading rate (2 and 5 mm/min) systems. These results showed that the high fracture toughness of the system at the low loading rate was due to the magnitude and region of the reorientation of the mesogenic groups in the fracture process and that high toughness could not be achieved at a high loading rate because the loading rate was too fast to allow orientation of the networks containing the mesogenic groups. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1296–1302, 2005     

Classification of Extremal Formally Self-Dual Even Codes of Length 22

 Lengths 22 and 30 are so far the only open cases in the classification of extremal formally self-dual even codes. In this paper, a classification of the extremal formally self-dual even codes of length 22 is given. There are 41520 such codes.A variety of properties of these codes are investigated. In particular, new 2-(22, 6, 5) designs are constructed from the codes. Received: February 9, 2000     

A subfringe integration method for multiple-beam Fizeau fringe analysis

Some aspects concerning the subfringe integration method in interferogram analysis have been investigated and modified. The modified algorithm, introduced in this paper, is capable of reconstructing the phase in the presence of noise or errors in carrier frequency. The subfringe integration method was applied to analyze two computer simulated patterns of equispaced Fizeau fringes using N bucket integration. Also, it is used to analyze the multiple-beam Fizeau fringe. The refractive index profile of polyethylene fiber is obtained by using two methods, subfringe integration method, and Fourier transform method. A comparison between the obtained results using the maintained methods is presented.     

Structure of thiotropocin,a new sulfur-containing 7-membered antibiotic

The structure of a new antibiotic thiotropocin is described.     

Einflu? von kationischen Polyelektrolyten auf die Reaktion von Chloracetat mit Thiosulfat

Ohne Zusammenfassung