The effect of Na addition on the first hydrogen absorption kinetics of cast hypoeutectic Mg–La alloys

With superior properties of Mg such as high hydrogen storage capacity (7.6 wt% H/MgH₂), low price, and low density, Mg has been widely studied as a promising candidate for solid-state hydrogen storage systems. However, a harsh activation procedure, slow hydrogenation/dehydrogenation process, and a high temperature for dehydrogenation prevent the use of Mg-based metal hydrides for practical applications. For these reasons, Mg-based alloys for hydrogen storage systems are generally alloyed with other elements to improve hydrogen sorption properties. In this article, we have added Na to cast Mg–La alloys and achieved a significant improvement in hydrogen absorption kinetics during the first activation cycle. The role of Na in Mg–La has been discussed based on the findings from microstructural observations, crystallography, and first principles calculations based on density functional theory. From our results in this study, we have found that the Na doped surface of Mg–La alloy systems have a lower adsorption energy for H₂ compared to Na-free surfaces which facilitates adsorption and dissociation of hydrogen molecules leading to improvement of absorption kinetic. The effect of Na on the microstructure of these alloys, such as eutectic refinement and a density of twins is not highly correlated with absorption kinetics.     

Characterization and electrochemical properties of CF4 plasma-treated boron-doped diamond surfaces

The effect of CF₄ plasma etching on diamond surfaces, with respect to treatment time, was investigated using scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and electrochemical measurements. SEM observations and Raman spectra indicated an increase in surface roughening on a scale of 10–20 nm, and an increase in crystal defect density was apparent with treatment time in the range of 10 s to 30 min. In contrast, alteration of the diamond surface terminations from oxygen to fluorine was found to be rather rapid, with saturation of the F/C atomic ratio estimated from XPS analysis after treatment durations of 1 min and more. The redox kinetics of Fe(CN)₆^3−/4− was also found to be significantly modified after 10 s of CF₄ plasma treatment. This behavior shows that C–F terminations predominantly affect the redox kinetics compared to the effect on the surface roughness and crystal defects. The double-layer capacitance (C_dl) of the electrolyte/CF₄ plasma-treated boron-doped diamond interface was found to show a minimum value at 1 min of treatment. These results indicate that a short-duration CF₄ plasma treatment is effective for the fabrication of fluorine-terminated diamond surfaces without undesirable surface damage.     

Effectiveness of spatial representation in the formation of network communities: experimental study on community organizer

In this paper, we present and discuss Community Organizer, a system designed to support network communities. The main characteristic of Community Organizer is the use of spatial representations for the relationships among community members including the communications exchanged among these members. These spatial representations reflect the degree of closeness of interests and concerns among the members, and are intended to provide users with clues on how to form network communities. In order to investigate the effectiveness of the proposed spatial representations, we conducted experiments with two different versions of the software. One version offered meaningful spatial representations while the other version did not. The subjects who used the former software version felt a greater sense of ‘community’, enjoyed using the software more, and actively used it longer than the subjects using the latter software version (control condition). These results indicated that the proposed spatial representations are effective in supporting network community formation.     

Lipid-Lowering Effect of Eriocitrin, the Main Flavonoid in Lemon Fruit, in Rats on a High-Fat and High-Cholesterol Diet

ABSTRACT:  Eriocitrin (eriodictyol 7- O -β-rutinoside) is the main flavonoid in lemon fruit. In this study, eriocitrin was investigated for its lowering effect on serum and hepatic lipids in high-fat and high-cholesterol fed rats. Rats in the control group ( N = 6) were fed a 20% lard and 1% cholesterol diet for 21 d, and rats in the 0.35% eriocitrin group ( N = 6) and 0.70% eriocitrin group ( N = 6) were fed a diet supplemented with eriocitrin 0.35% and 0.70%, respectively. The content of hepatic total cholesterol and triglyceride in the eriocitrin group was no different from that of the control group. The total cholesterol, VLDL+LDL, triglyceride, and phospholipid in the serum of the 0.35% eriocitrin group showed significantly lower concentrations than the control group ( P < 0.05), although there was no difference in the HDL concentrations among the groups. The lowering effect of eriocitrin for serum total cholesterol was thought to be caused by a decrease in VLDL+LDL. The 0.35% eriocitrin group was shown to have a significant increase in excretion of fecal bile acid ( P < 0.05) and a tendency for enhanced hepatic m-RNA levels of LDL receptor in comparison with the control group.     

A 3-V, 2%-mW multibit current-mode ΣΔ DAC with 100 dBdynamic range

The area ratio of analog to digital for mixed-mode chip has been inversely proportional to the process design rule for a given dynamic range objective, in contradiction to the LSI trend. This paper presents a design approach to realize a high degree of size reduction with process design rules for analog circuitry and a signal processing architecture for digital circuitry. A five-level current-mode ΣΔ digital-to-analog converter (DAC) system reveals full scale total harmonic: distortion plus noise (THD+N) of -90 dB and dynamic-range of 100 dB at 3 V (low power of 22 mW). Analog-area down-scaling can be accomplished by this architecture to be 1.09 mm², using 0.6-μm double-poly double-metal (DPDM) CMOS. For the digital filter, a pipeline instruction sequence with multiplierless architecture also gives small area of 1.98 mm²     

A shell for signal interpretation expert systems

System monitoring and diagnosis through signal interpretation are important tasks in many engineering fields. Although monitoring or diagnosis expert systems help human experts a lot, it is not so easy to build a signal interpretation expert system. We have developed two expert systems for speech signal processing. The close analysis of the two systems revealed common functions and modules applicable to wide range of signal interpretation problems. On the basis of the experience, we have developed a shell for signal interpretation expert systems named SSI. In order to evaluate SSI, we also developed two expert systems by using it and obtained satisfactory results. This paper describes the design philosophy and architecture of SSI together with some examples.     

Calbindin-D 28 kD and parvalbumin in the horizontal cells of rat retina during development

Restless legs syndrome (RLS) and periodic limb movements in sleep (PLMS) are disorders that are common and disturbing to uremic patients. The treatment of these is problematic. Eight patients on chronic hemodialysis and continuous peritoneal dialysis completed a double-blind placebo-controlled crossover study using incremental doses of pergolide up to 0.25 mg at bedtime for treatment of RLS and sleep disruption. Five patients (62.5%) noted subjective improvement in restless legs symptoms and sleep quality. Objective results were improved only slightly by treatment. The percentage of the first hour in bed during which leg movements occurred decreased from 20.5 +/- 6.0 to 11.5 +/- 3.3, p < 0.05. However, findings during sleep were less positive. The following measures were not significant between placebo and treatment: leg movements per hour of sleep [53.7 +/- 22.3 vs 35.8 +/- 11.8 (p = 0.2)]; and percentage of sleep time spent with leg movements [5.5% +/- 3.2 vs 4.4% +/- 1.4 (p = 0.37)]. Patients continued to have very disrupted sleep, and we could not document an objective improvement in sleep architecture. Thus, although pergolide at the dose of 0.25 mg at bedtime provided subjective improvement in symptoms of restless legs and quality of sleep, and objectively decreased leg movements during the first hour in bed, objectively sleep continued to be disrupted. In this small patient group, the response to pergolide was not uniform, and further investigation is required to test effectiveness at higher doses.