Acid formation from various sulfonates in a chemical amplification positive resist

The quantum yield for acid generation from alkyl and arylsulfonic acid esters of pyrogallol was measured in resist films composed of a sulfonate, tBOC-BA, and novolak resin. It was found that the quantum yield increases with decreasing molecular size of the sulfonyl group, which can explain the differences in sensitivity of the resist systems. Methanesulfonic acid esters of various phenol derivatives were synthesized to see the effect of backbone structure on the efficiency of acid generation. The sensitivity measurement of resists containing these sulfonates indicates that the number of sulfonyloxy groups bonded to a benzene ring is important. The higher number of the sulfonyloxy groups gives a higher efficiency of acid generation.     

Vibrations of probe used for the defect detection of helical heating tubes in a fast breeder reactor: Part 2. Vibration analysis and numerical simulations

A detection of a defect of a helical heating tube installed in the fast breeder reactor “Monju” in Japan is done by a feeding of an eddy current testing (ECT) probe with magnetic sensor into the tube. An undesirable vibration of the ECT probe always happens under a certain condition and makes the inspection difficult. Several characteristics of the vibration have been made clear by some experiments using a mock-up, but the essential factor of the vibration is still unclear. In this paper, a numerical simulation of the vibration is implemented on the assumption that the vibration is caused by Coulomb friction. An analytical model, which is obtained as a lumped mass model, is a large-scale non-linear vibration system and many computational costs are ordinarily required to carry out the simulations. The Transfer Influence Coefficient Method is applied so that the simulation is efficiently carried out. The results of simulation qualitatively agree well with the experimental results. It confirms the validity of the assumption that the vibration is caused by Coulomb friction.     

Homomorphisms between models of parallel computation

To better understand the relationships between different models of parallel computation, we introduce a new computation system formulation and develop general notions of homomorphisms and isomorphisms between computation systems. This allows us to study relations between vector addition systems, vector replacement systems, Petri nets, and generalized Petri nets. Results in this paper that may be of particular interest include a long list of properties preserved under homomorphism, and constructions that show that vector replacement systems can be simulated by vector addition systems, and that generalized Petri nets can be emulated by Petri nets.     

Photoinduced grafting of acrylamide onto polyethylene film by means of two-step method

Benzophenone-coated low-density polyethylene (LDPE) was grafted with acrylic acid (AA), methacrylic acid (MA), acrylonitrile (AN), and methyl methacrylate (MMA) in an aqueous medium by photoirradiation. The first-step graft samples thus prepared with a grafting of about 50% were subjected to second-step photografting with acrylamide (AAm). On AA- and MA-grafted LDPE samples, the second-step grafting of AAm was very smooth, and a high level of grafting up to 800% was attained with ease. On the other hand, grafted LDPE samples employing hydrophobic monomers, AN and MMA, had a lower percent of grafting than those with hydrophilic monomers, AA and MA. By ESR study, a thermally stable radical was found in the first-step graft sample irradiated with light of λ > 330 nm. Mechanisms for the formation of such a radical in the first-step graft sample are proposed, and the contribution of the radical to the second-step grafting is discussed.     

Ablation of Selenbp1 Alters Lipid Metabolism via the Pparα Pathway in Mouse Kidney

Selenium-binding protein 1 (Selenbp1) is a 2,3,7,8-tetrechlorodibenzo-p-dioxin inducible protein whose function is yet to be comprehensively elucidated. As the highly homologous isoform, Selenbp2, is expressed at low levels in the kidney, it is worthwhile comparing wild-type C57BL mice and Selenbp1-deficient mice under dioxin-free conditions. Accordingly, we conducted a mouse metabolomics analysis under non-dioxin-treated conditions. DNA microarray analysis was performed based on observed changes in lipid metabolism-related factors. The results showed fluctuations in the expression of numerous genes. Real-time RT-PCR confirmed the decreased expression levels of the cytochrome P450 4a (Cyp4a) subfamily, known to be involved in fatty acid ω- and ω-1 hydroxylation. Furthermore, peroxisome proliferator-activated receptor-α (Pparα) and retinoid-X-receptor-α (Rxrα), which form a heterodimer with Pparα to promote gene expression, were simultaneously reduced. This indicated that reduced Cyp4a expression was mediated via decreased Pparα and Rxrα. In line with this finding, increased levels of leukotrienes and prostaglandins were detected. Conversely, decreased hydrogen peroxide levels and reduced superoxide dismutase (SOD) activity supported the suppression of the renal expression of Sod1 and Sod2 in Selenbp1-deficient mice. Therefore, we infer that ablation of Selenbp1 elicits oxidative stress caused by increased levels of superoxide anions, which alters lipid metabolism via the Pparα pathway.     

Controlled in situ nanoscale enhancement of gold nanowire arrays with plasmonics

The controlled in situ growth of ordered gold nanoparticles and nanowire arrays has been studied by optically tracking changes in the local surface plasmon resonance (LSPR) spectrum. A spectrometer and custom-programmed analysis software track changes in the LSPR spectrum. The peak position, peak height (i.e. extinction intensity) and peak width (e.g. radius of curvature) were tracked over time to quantify the dynamic growth of gold as soon as the system was exposed to a commercial gold enhancement solution. This enables the controlled dynamic growth of nano-objects without the necessity of characterizing the growth and aggregation kinetics of the gold enhancement solution. The result was the successful enhancement of their electrically conductive and plasmonic properties, as well as the controlled growth and transformation of line-patterned nanoparticles into conductive particle-based nanowires.     

Risk assessment of short-chain chlorinated paraffins in Japan based on the first market basket study and species sensitivity distributions

The chemical risks of short-chain chlorinated paraffins (SCCPs) to human health and ecological species in Japan were assessed in this study. SCCPs are used as extreme pressure additives in metal-working fluids and flame retardant agents in plastic materials. The first market basket study with a high resolution gas chromatography and mass spectrometry with electron capture negative ionization is reported. Total daily food intakes for Japanese residents of different ages were estimated using Latin Hypercube simulations, and the highest 95th percentile intake is 6.8 x 10(2) ng/kg/day for a 1-year-old child. Based on the reported no-observed-adverse-effect-level (NOAEL) and the estimated exposure mainly from food, it was concluded thatSCCPs are not posing risks to humans in Japan. Ecological risks to aquatic and sediment organisms were estimated using species sensitivity distributions. The 95th percentiles of the distributions obtained by fitting several environmental SCCP concentration data of river water and sediment were 41.8 ng/L and 558 ng/g wet weight as the possible highest concentrations, respectively. No-observed-effect-concentrations (NOEC) were determined by calculating the fifth percentiles of a species sensitivity distribution, which were 2.2 microg/L for aquatic organisms and 1.7 to 13.5 mg/ kg wet weight for sediment organisms. While it is likely that there is no imminent environmental chemical risk for aquatic organisms at a regional level in Japan, this study concluded that a more detailed risk assessment is necessary for sediment organisms.     

Formation of electroless barrier and seed layers in a high aspect ratio through-Si vias using Au nanoparticle catalyst for all-wet Cu filling technology

An all-wet process was achieved using electroless deposition of barrier and Cu seed layers for fabrication of a high aspect ratio through-Si via (TSV). Formation of a thin barrier metal layer of Ni–B, Co–B and Co–W–B is possible using a Au nanoparticle (AuNP) catalyst, which is densely adsorbed on the SiO₂ of the TSV sidewall. A silane coupling agent of 3-aminopropyl-triethoxysilane is effective for enhancement of the density of adsorption for AuNP. A conformal electroless Cu layer is deposited on the barrier layer by displacement plating without a catalyst. The adhesion strength between the electroless barrier layer and the SiO₂ substrate is increased by annealing at 300 °C. These results strongly suggest that an all-wet process for the formation of Cu-filled TSV with a high aspect ratio is practically possible.