Schur and Schubert polynomials as Thom polynomials—cohomology of moduli spaces

The theory of Schur and Schubert polynomials is revisited in this paper from the point of view of generalized Thom polynomials. When we apply a general method to compute Thom polynomials for this case we obtain a new definition for (double versions of) Schur and Schubert polynomials: they will be solutions of interpolation problems.     

Pulse forming lines for square pulse generators

The designing of square pulse generators using pulse-forming lines (PFLs) made up of identical L and C, was reviewed in this study. Fourteen different types of PFLs were analyzed utilizing PSpice simulation results. These PFLs are described with respect to their distinct features-the number of forming lines (single or double), the circuit relationship of the PFL and load (parallel or series), and the types of energy storage (current source, voltage source or a combination of both). The characteristic impedance, output parameters such as pulsewidth, voltage and current magnitudes, and pulse power were derived for each scheme. The merits and demerits of the output parameters are also included.     

Reconstructive extremity dosimetry with 3D scanned hand model in MCNPX

We present a simulation method that can create accurate virtual models of hand with arbitrarily curved surfaces and perform distortion-free MCNPX simulations. Generally, MCNPX simulations of objects with arbitrarily curved surfaces are performed through voxelization. In this study, a polygon model is tetrahedralized by TetGen for the construction of the MCNPX geometry to be distortion-free. Then, dose estimation was successfully performed after converting the virtual model into an MCNPX input. A voxelized model was constructed for comparison purposes. The dose estimation functions of the two models were found to be similar, showing a similar amount of computing time by using the mesh tally option with 2e7 histories.     

Four-mirror imaging system (magnification +1/5) for ArF excimer laser lithography

Research was conducted on the axially symmetric four-mirror system (magnification +1/5) for use in optical lithography using an ArF excimer laser beam. The initial design is derived from an extensive numerical calculation that makes the sum of the third-order aberration coefficients very small _j=I ^V |S _j |<10_-6. Using an optimization method (damped least-squares method) the finite aberrations are reduced; then, to obtain the diffraction-limited performance, three surfaces are aspherized. The final system has NA=0.38 for the ArF excimer laser line (=0.193 m) and depth of focus of 1.2 m over a 2.6×2.6 cm² object field. Nearly all rays fall within the Airy disk in the image plane. The resolution is 540 cycles mm^-1 at MTF=0.5 level for axial object point. We consider that the present four-mirror system may be further refined for use in soft x-ray lithography.     

Self-aggregates of hydrophobically modified poly(2-hydroxyethyl aspartamide) in aqueous solution

Dehydrocholic acid (DHA) grafted poly(2-hydroxyethyl aspartamide) (PHEA)s were successfully synthesized and their self-aggregates in aqueous solution were characterized by fluorescence spectra and light scattering. PHEA was obtained by a simple reaction of ethanolamine with synthesized poly(succinimide) (PSI), and then PHEA-g-DHA was synthesized through an ester linkage between DHA and PHEA. The degree of substitution (DS) of DHA groups, defined by grafted mole%, was determined from both ¹H-NMR and elemental analysis. The grafting reaction of DHA was retarded up to almost 10 mole% feed ratio of DHA/PHEA, but increased linearly above the threshold ratio. Nano-size self-aggregates in aqueous solution were examined with four DSs less than 10. As DS increased, the critical aggregation concentrations (CAC) of polymers were continuously reduced and the size of primary aggregates reduced to as small as 40 nm in diameter. When stored, the sonicated aggregates of high DS were destabilized, apparently forming large aggregates with small curvatures. The formation of irreversible interfused secondary structures would be induced by the curvature change or aggregation of primary particles. A simple calculation indicates that a small change of separation between grafted DHA groups may induce the large curvature shift, in fact, sphere-to-planar surface transition.     

Chloromethanesulfonylethene and dichloromethanesulfonylethene: new reagents for tandem Diels-Alder/Ramberg-Bäcklund reactions

[reaction: see text] Chloromethanesulfonylethene (3a) and dichloromethanesulfonylethene (3b) were prepared by oxidation of the adducts of ethylene and ClCH(2)SCl or Cl(2)CHSCl, respectively, followed by NaHCO(3) dehydrochlorination. With dienes, 3a gave Diels-Alder adducts that, with base, underwent Ramberg-B?cklund reaction, giving products corresponding to the adducts of the dienes and allene. Similarly, 3b gave Diels-Alder adducts that, with base in the presence of the novel chlorine source MeSO(2)CCl(3), cleanly afforded products corresponding to the adducts of the dienes and 1,1-dichloropropa-1,2-diene.     

Validated HPLC determination of the two fixed dose combinations (chlordiazepoxide hydrochloride and mebeverine hydrochloride; carvedilol and hydrochlorothiazide) in their tablets

Simple, rapid, and selective RP-HPLC methods with UV detection were developed for simultaneous determination of chlordiazepoxide hydrochloride and mebeverine hydrochloride (Mixture I) and carvedilol and hydrochlorothiazide (Mixture II). The chromatographic separation in both mixtures was achieved by using an RP-C8 (octylsilyl) analytical column. For Mixture I, a mobile phase composed of acetonitrile-0.05 M disodium hydrogen phosphate-triethylamine (50 + 50 + 0.2, v/v/v), pH 2.5, was used; the detector wavelength was 247 nm. For Mixture II, the mobile phase consisted of acetonitrile-0.05 M disodium hydrogen phosphate (50 + 50, v/v), pH 4.0, and the detector was set at 220 nm. Quantification of the analytes was based on measuring their peak areas. Both mixtures were resolved in less than 6 min. The reliability and analytical performance of the proposed HPLC procedures were statistically validated with respect to linearity, range, precision, accuracy, selectivity, robustness, LOD, and LOQ. The linear dynamic ranges were 2.5-150 and 2.5-500 microg/mL for chlordiazepoxide HCI and mebeverine HCI, respectively, and 0.25-200 and 0.25-150 microg/mL for carvedilol and hydrochlorothiazide, respectively. The validated HPLC methods were successfully applied to the analysis of their commercial tablet dosage forms, for which no interfering peaks were encountered from common pharmaceutical adjuvants.