Etching of metallic materials with Cl2 gas cluster ion beam

Cluster ion beam processes exhibit high rate sputtering with low damage, and in particular, extremely high sputtering rates are expected using reactive cluster ion beams. Si could be sputtered at extremely high rates using reactive cluster ion beams, such as SF₆, Cl₂, CF₄, CHF₃, and CH₂F₂. However, processing of metallic materials with reactive cluster ion beams has not been studied yet. It was expected that high-speed etching of metallic materials can be realized with Cl₂ cluster ion irradiation, because such a beam would reactively sputter these materials. We generated a Cl₂ cluster ion beam and investigated the etching characteristics of various metallic materials, such as Ni and Al films, under this irradiation. The size of the Cl₂ cluster, as measured with a time-of-flight (TOF) system, was about 1400 molecules. The sputtering yield for each metal was more than 10 times higher than that obtained with Ar cluster ions, showing that Cl₂ cluster ion irradiation reactively sputtered the metallic materials. These results indicated that Cl₂ cluster ion irradiation was suitable for high-speed processing of metallic materials.     

Retardation of lipid oxidation in blue sprat by hot water tea extracts

The blue sprat is a small fish belonging to the family Clupeidae. Deterioration of its freshness after catching is so rapid that the fish is cooked in simple ways and consumed locally. The prooxidant activity of the skin, dark meat and ordinary meat was much higher than that of other fishes such jack mackerel. Suppression of lipid peroxidation in blue sprat was attempted using hot‐water extracts of five types of Taiwanese tea with different degrees of fermentation, ie Longjing‐type green tea, Shy Jih Chuen oolong tea, Tungting oolong tea, Pouchong tea and black tea. All the tea extracts showed antioxidant activity on oxidation of linoleic acid induced by the extracts of blue sprat's tissues. The antioxidant activity of each tea extract showed a positive correlation with the contents of total catechins, especially with that of epigallocatechin gallate, but a poor correlation with the contents of total polyphenols. The Tungting oolong tea together with Chinese green tea effectively suppressed the prooxidant activities of the dark meat and skin of blue sprat. Impregnation of blue sprat in the extract of the Tungting oolong tea retarded the lipid oxidation in fish meat assessed by peroxide value and carbonyl value during refrigeration. Copyright © 2005 Society of Chemical Industry     

Phosphorylation of starch and dextrin by dry-heating in the presence of phosphate,and their calcium phosphate-solubilizing ability

Starch and dextrin were phosphorylated by dry-heating in the presence of phosphate, and their properties were examined. The phosphorylation of starch was accelerated with decreasing moisture, rising incubation temperature and prolongation of the incubation period. However, a rise in incubation temperature, and lengthened incubation period caused increased browning and degradation. A decrease in the pH from 5.5 to 3.0 resulted in a modest increase of phosphorylation, but also marked browning and degradation. When potato starch was phosphorylated at 140 degrees C and pH 5.5 for 24 h, its phosphorus content was increased up to 3.47%, with fewer side reactions. Phosphorlylated starch and dextrin had calcium phosphate-solubilizing abitity. Phosphorylated dextrin with 2.42% phosphorus had about half the calcium phosphate-solubilizing ability of casein phosphopeptide (CPP). The possibility of substituting of phosphorylated starch and dextrin for CPP as a calcium phosphate-absorption enhancing material is discussed herein.     

Characteristics of Spherical Shock Wave and Circular Pulse Jet Generated by Discharge of Propagating Shock Wave at Open End of Tube

When the shock wave propagating in the straight circular tube reaches at the open end, the impulsive wave is generated by the emission of a shock wave from an open end, and unsteady pulse jet is formed near the open end behind the impulsive wave under the specific condition. The pulse jet transits to spherical shock wave with the increase in the strength of shock wave. The strength is dependent on the Mach number of shock wave, which attenuates by propagation distance from the open end. In this study, the mechanism of generating the unsteady pulse jet, the characteristics of the pressure distribution in the flow field and the emission of shock wave from straight circular tube which has the infinite flange at open end are analyzed numerically by the TVD method. Strength of spherical shock wave, relation of shock wave Mach number, distance decay of spherical shock wave and directional characteristics are clarified.     

Results of analyses on fumarolic gases from F-1 and F-5 fumaroles of Vulcano, Italy

This paper describes the methods used to collect volcanic gases from Vulcano, and to perform the chemical and isotopic analyses. The results indicate a fluctuation of the chemical composition of the gases within a short period of time. The origin of the vapor is inferred to be a mixture of sea water and the local meteoric water with subsequent vapor-rock interactions. The origin of CO₂ is ascribed to marine carbonates. A contribution of sedimentary materials is also suggested by the high N₂/Ar ratio, and high δ¹⁵N of N₂. On the other hand, most of the He is concluded to be of mantle origin.     

Control of μc-Si/c-Si interface layer structure for surface passivation of Si solar cells

Outstanding passivation properties for p-type crystalline silicon surfaces were obtained by using very thin n-type microcrystalline silicon (μc-Si) layers with a controlled interface structure. The n-type μc-Si layers were deposited by the RF PE-CVD method with an insertion of an ultra-thin oxide (UTO) layer or an n-type amorphous silicon (a-Si : H) interface layer. The effective surface recombination velocity (SRV) obtained was very small and comparable to that obtained using thermal oxides prepared at 1000°C. The structural studies by HRTEM and Raman measurements suggest that the presence of UTO produces a very thin a-Si : H layer under the μc-Si. A crystal lattice discontinuity caused by these interface layers is the key to a small SRV.     

A phase-field simulation of uranium dendrite growth on the cathode in the electrorefining process

The uranium dendrite growth on the cathode during the pyroprocessing of uranium is investigated using a novel phase-field model, in which electrodeposition of uranium and zirconium from the molten-salt is taken into account. The threshold concentration of zirconium in the molten salt demarcating the dendritic and planar growth is then estimated as a function of the current density. Moreover, the growth process of both the dendritic and planar electrodeposits has been demonstrated by way of varying the mobility of the phase field, which consists of the effect of attachment kinetics and diffusion.     

WAZA-ARI: computational dosimetry system for X-ray CT examinations II: development of web-based system

A web-based dose computation system, WAZA-ARI, is being developed for patients undergoing X-ray CT examinations. The system is implemented in Java on a Linux server running Apache Tomcat. Users choose scanning options and input parameters via a web browser over the Internet. Dose coefficients, which were calculated in a Japanese adult male phantom (JM phantom) are called upon user request and are summed over the scan range specified by the user to estimate a normalised dose. Tissue doses are finally computed based on the radiographic exposure (mA s) and the pitch factor. While dose coefficients are currently available only for limited CT scanner models, the system has achieved a high degree of flexibility and scalability without the use of commercial software.     

WAZA-ARI: computational dosimetry system for X-ray CT examinations. I. Radiation transport calculation for organ and tissue doses evaluation using JM phantom

A web system of WAZA-ARI is being developed to assess radiation dose to a patient in a computed tomography examination. WAZA-ARI uses one of organ dose data sets corresponding to the options selected by a user to describe examination conditions. The organ dose data have been derived by the Particle and Heavy Ion Transport code system, combined with Japanese male (JM) phantom. The configuration of JM phantom is adjusted to the averaged JM adult. In addition, a new phantom is introduced by removing arms from JM phantom to take into account for dose calculations in torso examinations. Some of the organ doses by JM phantom without arms are compared with results obtained by using a MIRD-type phantom, which was applied in some previous dosimetry systems.     

Consumer Acceptability of Muffins with Flaxseed (Linum usitatissimum)

Flaxseed has recently gained attention as a functional food. The effect of adding flaxseed (7.3%, 11.6%, and 15.5%) to muffins on consumer acceptability was evaluated by a focus group, hedonic scoring, and food action rating scale (FACT). The majority of consumers (82.6%, P < 0.001) rated the control muffin (0 % flaxseed) higher than the flax muffin for appearance, color, flavor, texture, overall acceptability, and food acceptance. Flaxseed muffin (11.6%) was “neither liked nor disliked” to “liked slightly” in overall acceptability. This may have been accounted for by the observation that many persons aged 18 to 25 y did not think they needed to consume “health foods”. This “indifferent” and in some cases “negative” attitude toward the flax muffins, which they considered a “health food”, may have influenced the ratings the flax muffins received. Texture and flavor were strongly and positively correlated (P < 0.01) to overall acceptability. A flaxseed muffin provided at least 16% fiber of the daily recommended value.