基于超声波反射法检测钢管腐蚀分布的观测实验

为降低钢管被腐蚀后对工业生产及人身安全所造成的潜在危害,研究钢管壁厚度的无损检测及推断腐蚀的分布。根据超声波通过不同介质分界面时会发生反射这一特点,用检测到的反射波形进行数据处理,从而计算出被测钢管壁的厚度,并利用互相关函数法提高反射信号间延迟的分辨精度,从而准确地推断出钢管壁的腐蚀分布。     

Proton-conducting electrolyte membranes based on hyperbranched polymer with a sulfonic acid group for high-temperature fuel cells

The hyperbranched polymers (HBP-SA-Acs) with both a sulfonic acid group as a functional group and an acryloyl group as a cross-linker at terminals in different ratios of sulfonic acid group/acryloyl group (SO₃H/Ac) were successfully synthesized as a new thermally stable proton-conducting electrolyte. The cross-linked hyperbranched polymer electrolyte membranes (CL-HBP-SAs) were prepared by thermal polymerizations of the HBP-SA-Acs using benzoyl peroxide, and their ionic conductivities under dry condition and thermal properties were investigated. The ionic conductivities of the CL-HBP-SAs were found to be in the range of 2.2 × 10⁻⁴ to 3.3 × 10⁻⁶ S/cm, depending upon the SO₃H unit contents, at 150 °C under dry condition, and showed the Vogel-Tamman-Fulcher (VTF) type temperature dependence, indicating that proton transfer is cooperated by local polymer chain motion. All CL-HBP-SAs were thermally stable up to 260 °C, and they had suitable thermal stability as electrolyte membranes for the high-temperature fuel cells under dry condition. Fuel cell measurement using a single membrane electrode assembly cell with a cross-linked electrolyte membrane was successfully performed under non-humidified condition. It was demonstrated that applying the concept of dry polymer system to proton conduction is one possible approach toward high-temperature fuel cells.     

Design and Analysis of Vertical Split Ring Resonator and Its Application to Unbalanced–Balanced Filter

We present a design method and analysis for a vertical split ring resonator (SRR). Furthermore, we propose an unbalanced–balanced filter using vertical SRRs. First, we explain vertical SRR with a stepped impedance resonator (SIR) using virtual ground. The resonance frequency is theoretically derived based on asymmetric coupled transmission lines. The resonance frequencies of vertical SRRs, calculated by our derived equation, are in good agreement with those of 3-D simulations and measurements. Next, this resonator is applied to an unbalanced–balanced filter based on low-temperature co-fired ceramic (LTCC). The attenuation poles of this filter are controlled by coupling between high-impedance lines similar to a two-pole filter with a SIR. The dimensions of the measured filter implemented with LTCC are 2.0 $times$ 1.2 $times$ 0.60 mm. The insertion loss is 2.80 dB in a 2.4-GHz band. Good agreement between measured and computed results is obtained.      

The effects of di-D-fructofuranose-1,2':2,3'-dianhydride (DFA III) administration on human intestinal microbiota

Di-D-fructofuranose-1,2':2,3'-dianhydride (DFA III) was shown to enhance Ca absorption in rat and human intestine. The effects of DFA III administration (9 g per day for 4 weeks that corresponded to 3-fold the optimal dosage of DFA III) on human intestinal microbiota were studied using denaturing gradient gel electrophoresis (DGGE). The major groups of human intestinal microbiota reported previously: the Bacteroides, the Clostridium coccoides group (Clostridium cluster XIVa), the Clostridium leptum group (Clostridium cluster IV), and the Bifidobacterium group were detected. The similarity of 30 DGGE profiles based on the V3 region (before and after administration to the 15 subjects) of the 16S rDNA were calculated using Pearson's correlation based on numbers, positions and intensity of bands, and then a dendrogram of DGGE profiles was constructed by the unweighted pair group method using arithmetic average (UPGMA) clustering method. By these analyses, no difference in DGGE profiles after DFA III administration was observed in healthy subjects, while two subjects with chronic constipation showed different profiles, namely on numbers, positions and the intensity of some bands. Their stools were softer and stool frequencies increased and they obtained relief from constipation.     

Analysis of mark-formation process for phase-change media

The objective of this study was to determine the mechanism of a phenomenon peculiar to phase-change recording regarding the mark shape or mark-forming process. The following results were obtained from our simulation of mark shapes, transparency electron microscope observations, and analysis of reproduced signals. A method of calculating a mark shape by calculating the holding-time profile was devised and its appropriateness was confirmed. We found there were close relationships between the cooling pulse shape, the effective erase ratio, the reproduced signal amplitude, and the noise level, and that the temperature change when the mark edge was cooled has a great influence on the stability of the mark shape and crystallized regions     

Protein interactions of Gts1p of Saccharomyces cerevisiae throughout a region similar to a cytoplasmic portion of some ATP-binding cassette transporters

The GTS1 gene product, Gts1p, has pleiotropic effects on the timing of budding, cell size, heat tolerance, sporulation and the lifespan of the yeast Saccharomyces cerevisiae. In this study, we found (using the yeast two-hybrid system) that Gts1p forms homodimers throughout the 18-amino acid region 296-313 which has considerable similarity to a region downstream of the Walker nucleotide-binding motif A of some ATP-binding cassette (ABC) transporters. The region contains two aspartic acid residues at 301 and 310 preceded by hydrophobic amino acid residues, and Gts1p with an Asp310 to Ala substitution showed considerably reduced homodimerization, as shown by the two-hybrid assay. Overexpression of the point-mutated Gts1p did not efficiently induce the Gts1p-related phenotypes described above, suggesting that the homodimerization of Gts1p is required for it to function in vivo. The C-terminal cytoplasmic domain of the yeast ABC transporters Mdl1p (multidrug resistance-like transporter) and Ycf1p (yeast cadmium factor or glutathione S-conjugate pump) bound to Gts1p in the two-hybrid system, and the heterodimerization activity of the Gts1p with the Asp301 to Ala substitution was more affected than the Gts1p with the Asp310 to Ala substitution. Overexpression of GTS1 considerably reduced, and disruption of GTS1 slightly decreased, cellular resistance to cycloheximide, cadmium, cisplatin and 1-chloro-2,4-dinitrophenol, which (except for cycloheximide) are all substrates of Ycf1p. These results suggest that Gts1p interacts with some ABC transporters through the binding site overlapping that of homodimerization and modulates their activity.     

Calculations of heats of formation for nitroaromatics with PM3 and MM2

Abstract

We have attempted to calculate heats of formation (Δ H _f °) for various aromatic nitro compounds with the semi-empirical molecular orbital theory and the molecular mechanics. As the results we may say that PM3, a semi-empirical MO method, and MM2, molecular mechanics, can estimate Δ H _f ° of energetic materials with accuracy enough to use Δ H_f° for energy hazards prediction. In case of aromatic polynitro compounds, both methods may be able to calculate accurate Δ H_f°.     

Tribological Properties and Film Formation Behavior of Thermoreversible Gel Lubricants

The tribological properties of a new and unique thermoreversible gel lubricant (TR gel lube) were investigated. TR gel lube, which includes 10–40% of amide-type gelling agent in base fluid, is able to repeatedly alter or convert phase from gel state to liquid state at the melting point of the gelling agent. High-pressure rheological tests were performed in order to characterize the behavior of base oil and TR gel lube as a function of pressure and temperature. The effect of TR gel lube on ball bearing fatigue life was carried out by systematic tests using thrust ball bearings. The results of L ₁₀ life tests of TR gel lube showed a longer life than the conventional greases. This result was investigated from the oil film formation. It was found that the gelling agent played a key role in the lubricating properties. Some mechanisms such as adsorbed film formation and solid-like formation are proposed.