Hadron production near threshold

Final state interaction effects inpp→ pΛK ⁺ andpd →³Heη reactions are explored near threshold to study the sensitivity of the cross-sections to thepΛ potential and theηN scattering matrix. The final state scattering wave functions between Λ andp andη and³He are described rigorously. The Λ production is described by the exchange of one pion and aK-meson between two protons in the incident channel. Theη production is described by a two-step model, where in the first step a pion is produced. This pion then produces anη by interacting with another nucleon     

Rapid shear viscosity calculation by momentum impulse relaxation molecular dynamics

Recently, Arya et al. [J. Chem. Phys. 113, 2079 (2000)] introduced a new molecular dynamics method to rapidly compute the viscosity of fluids. The technique, termed momentum impulse relaxation (MIR), involves the imposition of a Gaussian velocity profile on an equilibrated system, after which the decay in the profile is monitored as a function of time. The shear viscosity is computed by matching the rate of decay of the velocity profile to the corresponding solution of the Navier-Stokes equation. The method was originally applied to simple systems (argon and n-butane) and found to give a comparable accuracy to conventional equilibrium and nonequilibrium methods with more than an order of magnitude reduction in computing time. In this work, we extend and generalize the method to examine larger molecules with higher viscosities than have been examined previously. A detailed analysis of the method is given, including the effect the velocity boundary conditions have on the viscosity, the sensitivity of the results to the velocity profile fitting procedure, the effect of preequilibration of the Gaussian profile, and the effect the system size and box shape have on the accuracy and speed of the method. It is shown that the MIR method can be extended to treat multiatom systems without loss of accuracy or computational efficiency.     

2-（1,3-Diphenylpropen-1,3-diolato）-1,3,2-（5-formylbenzo）dioxaborol： A ＇Whole-molecule Disorder＇ Crystal Structure

The boron atom in C22H15BO5 is O,O’-chelated by the anions in a tetrahedral geometry, with the planar five-and six-membered chelate rings being orthogonal to each other. The molecule lies on a two-fold rotation axis. The molecule is disordered with respect to another molecule in a 93:7 ratio; the treatment of the ‘whole-molecule disorder’ by employing a large number of restraints is described. Crystal data: C22H15BO5, monoclinic C2/c, a = 17.1804(5), b = 12.9409(4), c = 9.8842(3) , β = 124.832(2)o, V = 1803.82(9) 3 at –173 K.     

Transfer measurements for the Ti+Ni systems at near barrier energies

Large enhancements have been observed in the sub-barrier fusion cross sections for Ti+Ni systems in our previous studies. Coupled channel calculations incorporating couplings to 2⁺ and 3⁻ states failed to explain these enhancements completely. A possibilty of transfer channels contributing to the residual enhancements had been suggested. In order to investigate the role of relevant transfer channels, measurements of one- and two-nucleon transfer were carried out for ^46,48Ti+⁶¹Ni systems. The present paper gives the results of these studies.     

Water-alcohol Separation by Pervaporation through Zeolite Modified Poly(amidesulfonamide)s (PASAs)

A series of poly(amidesulfonamide)s (PASAs) which have been synthesized in our laboratory possess good membrane fabrication properties^[1]. The potential use of these membrane materials in RO, UF and PV were demonstrated^[2,3]. Reminiscent to the PV performance of other glassy polymers, most of these materials exhibit a fairly high separation factor albeit a permeation flux below 35 g m^-2 h^-1 in the PV separation of aqueous alcohol mixtures. To have a real application prospect in PV, the permeation flux through the membranes has to e further improved. The present work represents our effort to upgrade the separation characteristics of PASAs by blending with inert hydrophilic zeolites. Three types of PASAs (structure shown in Figure 1) were selected to be fabricated by blending different amount of zeolite NaA or NaX. The zeolite filled membranes were characterized by SEM, IR spectroscopy, sorption measurements and wide-angle X-ray diffraction. By adding proper amount of NaA into the polymer casting solutions, the resultant zeolite filled membranes exhibited improvement in both selectivity and permeability in the separation of 10% aqueous solutions of ethanol, propan-l-ol and propan-2-ol, as compared to the zeolite free membrane (Table 1).     

Light-mediated transformations of olefins into alcohols: reactions of hydroxyl radicals with cycloalkenes

Reactions of hydroxyl radicals, generated by photodecomposition of hydrogen peroxide in acetonitrile, with a wide variety of cycloalkenes have been examined. The results show that the major reaction is the addition of hydroxyl radicals to the less substituted end of the double bond, furnishing the secondary alcohols. The reactivity pattern and the observed regio- and stereoselectivity clearly reveal that the steric parameters associated with the substrates play a dominant role in directing the addition reactions. More importantly, this study led to the development of a new methodology for the facile conversions of olefins essentially into secondary alcohols, and includes a few examples which demonstrate the potential of the method.     

Nonlinear Filtering in Rieznnnnifln Manifolds

A general formulation of the nonlinear filtering problem inRiemanman manifolds is given by use of the strong solutionsof the stochastic differential equations for the state and observationprocesses in the orthonormal frame bundles of the state andobservation process manifolds, respectively. A general Bayesformula for the conditional expectation of smooth functionsof the state process is given. This is used to give a directderivation of the Zakai equation for the general problem underconsideration. An example is presented.     

DC Electrical Study of Modified PMMA,PVC and their Blend

Summary: Thin films of high molecular weight PMMA, PVC and their blend were prepared with solution cast method. Further they were modified by adding Camphor Sulphonic Acid (CSA) to them. DSC studies indicate single glass transition temperature (Tg) for unmodified as well as modified blends indicating the miscibility of polymers. FTIR studies show the interaction between CSA-PVC, CSA-PMMA, CSA-(PVC+PMMA) blend. The D.C. electrical study was carried out at various temperatures from room temperature (307 K) to 373 K. After modification the variation of DC conductivity (σ) is found to decrease in PVC and the PVC-PMMA blend whereas it is found to increase in PMMA with rise in temperature.