Global-vector representation of the angular motion of few-particle systems II

The angular motion of a few-body system is described with global vectors which depend on the positions of the particles. The previous study using a single global vector is extended to make it possible to describe both natural and unnatural parity states. Numerical examples include three- and four-nucleon systems interacting via nucleon-nucleon potentials of AV8 type and a 3α system with a nonlocal αα potential. The results using the explicitly correlated Gaussian basis with the global vectors are shown to be in good agreement with those of other methods. A unique role of the unnatural parity component, caused by the tensor force, is clarified in the 0^? ₁ state of ⁴He. The two-particle correlation function is calculated in the coordinate and momentum spaces to show different characteristics of the interactions employed.     

Influence of the solvent on nature of gate effect in molecularly imprinted membrane

The solute diffusive permeability in a thin layer of a molecularly imprinted polymer (MIP) is affected by specific binding of the MIP with a template. This phenomenon, termed the "gate effect," would be widely applicable for the development of novel biomimetic sensors. However, the mechanism underlying the gate effect is not totally understood. We present here investigation of the role of specific adsorption of a template and solution content in MIPs on the gate effect. A molecularly imprinted self-supporting membrane was formed by copolymerization of methacrylic acid, 2-vinylpyridine, and triethyleneglycol dimethacrylate in the presence of L- (or D-) phenylalanine as a template. The template adsorbed by membrane with degree of enantio-selectivity in a mixed solvent of methanol and water. The amount of adsorption and binding selectivity showed little sensitivity to the solvent composition. The solution content in the membrane increased with increasing the methanol concentration of the solvent following a sigmoid curve with an inflection point at methanol concentration of 20 wt.%. The content increased in the presence of the template at methanol concentrations higher than the inflection point, and decreased at lower methanol concentrations. The creatinine permeability across the membrane estimated by batchwise dialysis increased in the presence of the template at 50 wt.% methanol in the solvent, and did not change at 20 wt.%. There was no permeability for creatinine in the pure water solvent. Both the solution content and the permeability were not affected by the presence of the enantiomer of the template. The results show that the choice of solvent controls more strongly the nature of the gate effect than the specific binding of the template.     

3D atomic imaging by internal-detector electron holography

A method of internal-detector electron holography is the time-reversed version of photoelectron holography. Using an energy-dispersive x-ray detector, an electron gun, and a computer-controllable sample stage, we measured a multiple-energy hologram of the atomic arrangement around the Ti atom in SrTiO3 by recording the characteristic Ti Kα x-ray spectra for different electron beam angles and wavelengths. A real-space image was obtained by using a fitting-based reconstruction algorithm. 3D atomic images of the elements Sr, Ti, and O in SrTiO3 were clearly visualized. The present work reveals that internal-detector electron holography has great potential for reproducing 3D atomic arrangements, even for light elements.     

Development and test of SEOP neutron spin filter in Japan

We have begun the development of an in-situ spin-exchange optical pumping (SEOP) system aiming to use it as a neutron spin filter for incident beam polarization at the Japan Proton Accelerator Research Complex (J-PARC). To use it, it is recommended that the optics be adjusted easily, have high stability, and have a small size. In this paper we improved our previous SEOP system aiming to use it in J-PARC and performed a neutron beam test at the JRR-3 NOP beamline to see the performance of the neutron spin filter (NSF). The polarization of the ³He gas reached 73%. This paper gives the present status of the development of in-situ SEOP system in J-PARC.     

A New Asymptotic Perturbation Theory with Applications to Models of Massless Quantum Fields

Let H ₀ and H _I be a self-adjoint and a symmetric operator on a complex Hilbert space, respectively, and suppose that H ₀ is bounded below and the infimum E ₀ of the spectrum of H ₀ is a simple eigenvalue of H ₀ which is not necessarily isolated. In this paper, we present a new asymptotic perturbation theory for an eigenvalue E(λ) of the operator ${H(\lambda)\,:=\,H_0 + \lambda H_{I}\,(\lambda \in \mathbb{R} \setminus \{0\})}$ satisfying lim _{λ → 0} E(λ) = E ₀. The point of the theory is in that it covers also the case where E ₀ is a non-isolated eigenvalue of H ₀. Under a suitable set of assumptions, we derive an asymptotic expansion of E(λ) up to an arbitrary finite order of λ as λ → 0. We apply the abstract results to a model of massless quantum fields, called the generalized spin-boson model (Arai and Hirokawa in J Funct Anal 151:455–503, 1997) and show that the ground-state energy of the model has asymptotic expansions in the coupling constant λ as λ → 0.     

Product line selection and pricing under a share-of-surplus choice model

Product line selection and pricing decisions are critical to the profitability of many firms, particularly in today’s competitive business environment in which providers of goods and services are offering a broad array of products to satisfy customer needs.We address the problem of selecting a set of products to offer and their prices when customers select among the offered products according to a share-of-surplus choice model. A customer’s surplus is defined as the difference between his utility (willingness to pay) and the price of the product. Under the share-of-surplus model, the fraction of a customer segment that selects a product is defined as the ratio of the segment’s surplus from this particular product to the segment’s total surplus across all offered products with positive surplus for that segment.We develop a heuristic procedure for this non-concave, mixed-integer optimization problem. The procedure utilizes simulated annealing to handle the binary product selection variables, and a steepest-ascent-style procedure that relies on certain structural properties of the objective function to handle the non-concave, continuous portion of the problem involving the prices. We also develop a variant of our procedure to handle uncertainty in customer utilities. In computational studies, our basic procedures perform extremely well, producing solutions whose objective values are within about 5% of those obtained via enumerative methods. Our procedure to handle uncertain utilities also performs well, producing solutions with expected profit values that are roughly 10% higher than the corresponding expected profits from solutions obtained under the assumption of deterministic utilities.     

Highly planar amphiphilic porphyrins

A first synthesis of an asymmetric and amphiphilic β-substituted porphyrin is reported. The porphyrin can be integrated into various types of nanostructures with the amphiphilic characters in hydrophilic solvents. The one-dimensional integration may induce a magnetic interaction between the central metals.     

Dielectric properties and conductivity of styrene-methacrylic acid copolymers and partially neutralized salts

Dielectric and conductivity measurements have been carried out on styrene-methacrylic acid copolymers and their salts in the glass transition region, stressing the comparison of polymers neutralized to different extents. A simple monomer-dimer equilibrium between carboxylic acid groups is applicable to the pure acid polymers, which explains the increase of both the glass transition temperature and of the dielectric strength with concentration of methacrylic acid. The dielectric data indicate that very few sodium carboxylate groups can dissolve in the matrix of the pure salt, whereas the presence of carboxylic acid groups in partly neutralized polymers enhances the dissolution of the salt groups in the matrix. Considerable differences are observed between the partly neutralized polymer and the blend consisting of pure acid and pure salt copolymers, which suggests that exchange of cations between acid and salt groups is quite slow even at high temperatures. The conductivity of the ionomers appears to be related to the diffusion of carriers through the matrix.     

Synthesis of 7‐acetyloxy‐3,7‐dimethy1‐7,8‐dihydro‐6H‐isochromene‐6,8‐dione and its analogues

7‐Alkanoyloxy‐3,7‐dimefhyl‐7,8‐dihydro‐6H‐isochromene‐6,8‐diones 12‐15 were synthesized in 69‐16% yields from the reaction of 2,4‐dihydroxy‐3‐methyl‐6‐(2‐oxopropyl)benzaldehyde 11 with p‐toluenesulfonic acid in various carboxylic acids such as acetic acid, propionic acid, butyric acid and heptanoic acid followed by oxidation with lead tetraacetate. On the other hand, (±)‐daldinin A 5 (oleate) was not obtained using oleic acid as a medium. In the cases of heptanoic acid and oleic acid, esters 16 and 17 were produced in 23 and 9% yields, respectively. 6,8‐Dihydroxy‐3,7‐dimethyl‐2‐benzopyrylium p‐toluenesulfonate 31 is considered as the intermediate for the production of 12‐15. Overall yields of isochromenes 12‐15 were 26‐6% starting from 2‐methylresorcinol for seven steps.