Quasi-Debye response of ion-hopping conduction at lowest frequencies

On the basis of the relaxation mode theory, quasi-Debye response in the dynamic conductivity by hopping ions is theoretically investigated in three-dimensional random lattices with a uniform distribution of activation energies. It is shown at lowest frequencies that the dynamic conductivity is approximately given by σ(ω)∼σ(0)+A″ω^s″, s″=2−n, where n is a non-integer exponent originated from the mode diffusion length and density of states. The numerical analyses give rise to some values of s″<2, for example s″∼1.5, which behaves as s″→2 with increasing temperature.     

Strain induced grain boundary premelting in bulk copper bicrystals

In bulk bicrystals strain induced grain boundary premelting (SIGBPM) occurs when heavy screw dislocation pileup can be held up to a certain high temperature, approximately 0.6T _M, where T _M is the melting point of bulk material in Kelvin. SIGBPM occurs at grain boundaries to which new twist component is added due to the rotation of both component crystals toward opposite direction about the axis perpendicular to the grain boundary plane. At the original grain boundary, grain boundary sliding takes place due to this relative rotation. In f.c.c. metals with relatively low stacking fault energies such as copper, nickel, brass(30Zn) and silver, dislocations dissociate into partials. Therefore high density tangled dislocations introduced during plastic deformation hardly loose. If these dislocations can be held to high temperatures, SIGBPM is promoted. Formation of static or dynamic recrystallized grains suppresses SIGBPM itself and the propagation of grain boundary cracks formed by SIGBPM.     

Real-time surface shape measurement by an active interferometer

We have succeeded in video rate analysis of fringes stabilized by an active interferometer placed outside optical benches. The interferometer uses the closed loop control of injection current of a laser diode to compensate for fringe movement that is detected by a spatial filtering detector. A video image of the locked fringes with tilt is supplied to the real-time fringe analyzer that delivers unwrapped phase distribution from the three phase shifted fringes generated by the electronic moiré method. For a concave mirror of 130 mm diameter placed on a wooden desk we observed the repeatability of λ/60 for P-V surface error of λ/5.     

Effect of polyphenols from Vicia faba L on lipase activity and melanogenesis

Two new flavonoid glycosides, kaempferol 3-O-α-L-rhamnopyranosyl (1→6) (3′′-acetyl)-β-D-galactopyranoside 1 and kaempferol 3-O-α-L-arabinopyranosyl-5-O-α-L-rhamnopyranoside 2, along with six known ones 3–8 were isolated from the flowers of Vicia faba L. (Fabaceae). Methanol extract and the isolated compounds were tested against lipase and melanogenesis inhibition activities and resulted in that compound 2 showed 53 and 77% lipase inhibition activity in concentrations of 400 and 800 μg/mL, respectively. For melanogenesis, compounds 2, 3 and 4 exhibited potent melanogenesis inhibition activity where the melanin content in melanoma cells was decreased to be about 57.5, 56 and 61%, respectively, with no obvious melanocytotoxicity. The rest of compounds showed weak to moderate activity. The results of melanogenesis inhibition activity of this study suggested the potential use of Vicia faba flowers as a skin-whitening agent and reveal the flowers to be a rich source of important phytochemicals with antilipase and melanogenesis inhibitory activity.     

Drying dissipative structures of Chinese black ink on a cover glass and in a dish

Macroscopic and microscopic dissipative structural patterns are formed in the course of drying a suspension of Chinese black ink on a cover glass and in a dish. The time for the drying and the pattern area increased as the particle concentration increased. The broad ring patterns of the hills accumulated with the particles formed around the outside edges on a macroscopic scale. The height and the width of the broad ring increased as the particle concentration increased. The spokelike patterns of the rims accumulated with particles were also formed on a macroscopic scale. Microscopic patterns of colloidal accumulation were observed over the whole region of the pattern area. Various types of convection cells were observed on a cover glass and in a dish at 25–80 °C. A time-resolved observation of the drying process was also made. The convections of water and the colloidal particles at different rates under gravity and the translational and rotational Brownian movement of the particles were important for the macroscopic pattern formation. Microscopic patterns were determined by the translational Brownian diffusion of the particles and the electrostatic and the hydrophobic interactions between the particles and/or between the particles and the cell wall in the course of the solidification of the particles.     

Substantial increase of the ordering temperature for [MnII/MoIII(CN)7]-based magnets as a function of the 3d ion site geometry: example of two supramolecular materials with Tc = 75 and 106 K

Two molecule-based magnets, [Mn(2)(tea)Mo(CN)(7)].H(2)O, 1, and [Mn(2)(tea)Mo(CN)(7)], 2 (tea stands for triethanolamine), formed with the 4d ion building block, [Mo(CN)(7)](4)(-), Mn(II) ions, and an additional ligand, tea, have been prepared and structurally characterized by single-crystal X-ray analyses. Whereas 1 is obtained by a self-assembling process in solution, compound 2 is quantitatively formed through a smooth thermal treatment of 1. Their magnetic properties revealed that these compounds exhibit magnetic ordering at T(c) = 75 and 106 K respectively for compounds 1 and 2. The difference for their critical temperature is attributed to the geometry of the coordination sphere of a Mn(II) site found to be square-pyramidal for 1 and tetrahedral for 2.     

Plans for implementation of a quality system in the control laboratory of the Romanian National Medicines Agency

This paper describes the practical implementation of a quality system in the control laboratory of the National Medicines Agency, Romania, the main aim being the alignment of the requirements of the control of drugs in Romania with European Union standards. Activity in this field is relatively new in Romania, however, it is of great importance to Romania’s compliance with international standards. Received: 13 September 2000 Accepted: 19 February 2001     

He accumulation effect in solid and liquid D-T mixture

This article reports the accumulation effect of the ³He originating from tritium β decay; ³He created in solid remains in it, while one in liquid diffuses and goes out to the vapor gas. We observed this effect through the neutron detection from muon catalyzed fusion phenomenon (μCF), and gave it qualitative understanding, by which the muon transfer rate from (dμ) and (tμ) to helium was derived. This revised version was published online in August 2006 with corrections to the Cover Date.     

Measurement of the K β /K α ratio for muon alpha sticking X-rays in muon catalyzed d-t fusion at the RIKEN-RAL Muon Facility

At the RIKEN-RAL Muon Facility, μ^- to α sticking K _β X-rays were observed for the first time taking advantage of the pulsed beam structure. The precision of the present measurements was insufficient to distinguish between theoretical models, however the observed K _β /K _α X-ray intensity ratio tends to be smaller than most of these theoretical predictions. This revised version was published online in August 2006 with corrections to the Cover Date.