A face-based monolithic approach for the incompressible magnetohydrodynamics equations

A novel numerical algorithm has been developed to solve the incompressible resistive magnetohydrodynamics equations in a fully coupled form. The numerical method is based on the face-centered unstructured finite volume approximation, where the velocity and magnetic field vector components are defined at the center of edges/faces; meanwhile, the pressure term is defined at element centroid. In order to enforce a divergence-free magnetic field, the gradient of a scalar Lagrange multiplier is introduced into the induction equation. A special attention will be given to satisfy the continuity equation and the Gauss' law for magnetism within each element and the summation of the equations can be exactly reduced to the domain boundary. The first modification to the original algorithm involves the evaluation of the convective fluxes over the two neighboring elements, where the discrete continuity equations are exactly satisfied. The second modification is based on the neglecting electric field term from the Lorentz force in two dimensions. The resulting large-scale algebraic linear equations are solved in a fully coupled manner using the one- and two-level restricted additive Schwarz preconditioners to avoid any time step restrictions forced by stability requirements. The spatial convergence of the algorithm is confirmed by solving the Hartmann flow, and then the algorithm is applied to the classical lid-driven cavity and backward facing step benchmark problems in two and three dimensions. The lid-driven cavity flow calculations at relatively high Stuart numbers indicate the perfect braking effect of the magnetic field in two dimensions.     

High spin level structure of 63 143 Eu80

The level scheme of ¹⁴³ Eu has been extended to I=75/2 in an experiment with the NORDBALL Compton-suppressed Ge detector array and the ¹¹⁰ Pd(³⁷ Cl, 4n) reaction. Most of the scheme shows irregular structure of multiparticle excitations. A strongly populated straight cascade of more than 10 stretched E2 transitions suggests the onset of collectivity.     

Toward the responsible innovation with nanotechnology in Japan: our scope

The societal impacts of nanotechnology have attracted growing attention in the United States and Europe in recent years. In Japan, the National Institute of Advanced Industrial Science and Technology (Technology Information Department) has played a central role in promoting discussions on this topic by collecting information from Japan and overseas, creating a network of the interested parties, and providing a forum for discussion. This paper presents a summary of recent activities in Japan relating to the societal impacts of nanotechnology, fro the launch of the “Nanotechnology and Society” open forum (August 2004) until the “Nanotechnology Debate” discussion forum (February 2007), and outlines the policy recommendations that came out of a project entitled “Research on Facilitation of Public Acceptance of Nanotechnology” (March 2006).     

Large optical nonlinearity of semiconducting single-walled carbon nanotubes under resonant excitations

We measured third-order nonlinear susceptibility (chi(3)) spectra in semiconducting single-walled carbon nanotubes (SWNTs) by the Z-scan method. |Imchi(3)| is remarkably enhanced under resonant excitation to the lowest interband transition, reaching 4.2 x 10(-6) esu and 1.5 x 10(-7) esu in SWNTs grown by the laser ablation and HiPco methods, respectively. A comparison of the transient absorption changes evaluated by degenerate and nondegenerate pump-probe measurements suggests that the resonant enhancement of |Imchi(3)| is dominated by a coherent process rather than by saturation of absorption.     

Adhesion between Nanoscale Rough Surfaces

In this investigation, the adhesion between particles and plates with root-mean-square, rms, surface roughness of 0.17-10.5 nm was measured by atomic force microscopy. Measurements obtained with particles both larger and smaller than the surface asperities are presented. Results indicate adhesion force decreases sharply with increasing surface roughness in the nanometer scale (<2 nm), followed by a gradual and slow decrease with further increase in roughness. Existing models were found to significantly underestimate adhesion force. Hence, a new model based on a geometry that considers both the height and breadth of asperities yielding an increased asperity radius compared to previous approaches, as detailed in Part I of this series, is applied using both van der Waals and elastic deformation/work of adhesion based approaches. For the system studied in this investigation, the adhesion forces predicted by the proposed model are considerably more accurate than those predicted by past models. Copyright 2000 Academic Press.     

Allenamides as Orthogonal Handles for Selective Modification of Cysteine in Peptides and Proteins

In this study, a remarkably simple and direct strategy has been successfully developed to selectively label target cysteine residues in fully unprotected peptides and proteins. The strategy is based on the reaction between allenamides and the cysteine thiol, and proceeds swiftly in aqueous medium with excellent selectivity and quantitative conversion, thus forming a stable and irreversible conjugate. The combined simplicity and mildness of the process project allenamide as robust and versatile handles to target cysteines and has potential use in biological systems. Additionally, fluorescent‐labeling studies demonstrated that the installation of a C‐terminal allenamide moiety onto various molecules of interest may supply a new methodology towards the site‐specific labeling of cysteine‐containing proteins. Such a new labeling strategy may thus open a window for its application in the field of life sciences.     

pH‐assisted homogeneous liquid–liquid microextraction using dialkylphosphoric acid as an extraction solvent for the determination of chlorophenols in water samples

In this study, a new pH‐assisted homogeneous liquid–liquid microextraction combined with HPLC with UV detection was developed for the determination of chlorophenols in water samples. In this approach, bis(2‐ethylhexyl) phosphate was used for the first time as the low‐density extraction solvent. In particular, 60 μL of bis(2‐ethylhexyl) phosphate was injected into the sample solution (5 mL) and dissolved completely in the sample solution while the pH was increased to 9. Afterwards, the pH of the sample solution was lowered to 1, and a cloudy solution was formed. At this stage, hydrophobic interactions between the analytes and the long double hydrocarbon chains of extraction solvent were expected to be the main forces driving extraction. A series of parameters that influence extraction were investigated systematically. Under the optimized conditions, the LODs and LOQs for the chlorophenols were 1.4–2.7 and 4.7–9.1 ng/mL, respectively. RSDs based on five replicate extraction of 100 ng/mL of each chlorophenols were <4.7% for intraday and 7.4% for interday precision. This method has been also successfully applied to analyze real water samples at two different spiked concentrations, and satisfactory recoveries were achieved.     

Single-step link of the superdeformed band in143Eu

²⁰⁹Fr has been produced by irradiation of¹⁹⁷Au with¹⁶O,and studied using a He-jet recoil tape transport system.A decay scheme is proposed for the first time,based on X-γ and γ-γ coincidence measurements,which takes account of 20 observed γ-rays. The branching ratio for (EC+β ⁺) decay of²⁰⁹Fr has been estimated to be 3.0±1.5%. Five members of low-lying states in²⁰⁹Rn can be explained with the configuration [(²¹⁰Rn 2⁺)(νf5/2)^?1].