Photografting of N‐isopropylacrylamide and glycidyl methacrylate binary monomers on polyethylene film: Effect of mixed solvent consisting of water and organic solvent

Photografting (λ > 300 nm) of N‐isopropylacrylamide (NIPAAm) and glycidyl methacrylate (GMA) binary monomers (NIPAAm/GMA) on low‐density polyethylene film (thickness = 30 μm) was investigated at 60°C using mixed solvent consisting of water and an organic solvent such as acetone. Xanthone was used as a photoinitiator by coating it on the film surfaces. A maximum percentage of grafting was observed at a certain concentration of acetone in the mixed solvent, which was commonly observed for both ratios of NIPAAm/GMA, 8/2 and 7/3. Based on the photografting of NIPAAm/GMA on xanthone‐coated film, monomer reactivity ratios of NIPAAm (r₁) and GMA (r₂) were calculated using the Fineman–Ross method. The values were 0.31 ± 0.1 and 4.8 ± 0.2 for the water solvent system, while they were 0.96 ± 0.1 and 4.9 ± 0.1 for the mixed solvent system. NIPAAm/GMA‐grafted films with a homogeneous distribution of grafted chains were formed by photografting using water and mixed solvents. The NIPAAm/GMA‐grafted films exhibited temperature‐responsive characters, whereas the grafted films showed a reversible change in the degree of swelling between 0 and 50°C, respectively. Epoxy groups in the grafted poly(NIPAAm/GMA) chains could be aminated with ethylenediamine in N,N′‐dimethylformamide at 70°C for 3 h. Complexes of the aminated NIPAAm/GMA‐grafted chains with cupric ion exhibited catalytic activity for the decomposition of hydrogen peroxide at 20 to 50°C. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2469–2475, 2005     

Shape optimization of continua using NURBS as basis functions

The present paper introduces a numerical solution to shape optimization problems of domains in which boundary value problems of partial differential equations are defined. In the present paper, the finite element method using NURBS as basis functions in the Galerkin method is applied to solve the boundary value problems and to solve a reshaping problem generated by the H1 gradient method for shape optimization, which has been developed as a general solution to shape optimization problems. Numerical examples of linear elastic continua illustrate that this solution works as well as using the conventional finite element method.     

Fluxless fabrications of Sn-Au solder microbumps by a hydrogen plasma reflow technique

Solder microbumps of 0.95Sn-0.05Au were successfully fabricated on a compound semiconductor wafer by reflowing a multilayer metal film in hydrogen plasma atmosphere. The microbumps melt at as low a temperature as 220°C, which is close to the lowest eutectic temperature (217°C) in a Sn-Au system. Fluxless reflowing was achieved by using hydrogen radicals. The low-temperature fluxless fabrication of Sn-Au solder microbumps is a very useful technique for electrical connection between a compound semiconductor chip and a substrate.     

Investigation of meshing phenomenon of hypoid gears with different offsets via high response infrared video thermography

Forschung im Ingenieurwesen - Hypoid gears are widely used in automobile differentials. Furthermore, it is well known that the efficiency of hypoid gears is lower than that of other gears due to...     

在高浓度尿素的存在下采用制备型电泳体系进行聚丙烯酰胺凝胶电泳分离腐植酸成分

采用制备型电泳体系在高浓度的尿素存在下进行聚丙烯酰胺凝胶电泳分离水溶性腐植酸中的不同成分。在聚丙烯酰胺凝胶电泳中,根据水溶性腐植酸中深色成分分子大小的不同能够将它们彼此分离开来,同时还可以通过酸沉淀的方法将这些深色物质重新回收。水溶性腐植酸中大部分的荧光物质分子尺寸都很小,这使得它们可以溶于酸,并且被酸溶解的荧光物质可以通过吸附在DAX-8树脂上而重新获得。但是,水溶性腐植酸中的非荧光物质则会在电泳过程中丢失。而那些被认为是小分子的荧光物质则会通过氢键的断裂和7 M尿素的疏水作用得到分离。漫反射傅里叶变换红外光谱的测量结果表明腐植酸中不同成分的化学性质是不同的。而实验结果表明在高浓度尿素存在下聚丙烯酰胺凝胶电泳是分离和收集水溶性腐植酸中各组分的一种很有用的方法。     

Toxicity of four antifouling biocides and their mixtures on the brine shrimp Artemia salina

Zinc pyrithione (ZPT), Copper pyrihione (CPT), Chlorothalonil and Diuron are four of the most widely used as alternative to tributlytin (TBT) antifouling biocides in boat paints. As most previous laboratory bioassays for these biocides have been conducted solely based on acute tests with a single compound, information on the possible combined toxicity of these common biocides to marine organisms are limited. In this study, the toxicity of binary (in several proportions), ternary and quaternary mixtures were evaluated using the brine shrimp Artemia salina as test organism. Mixture toxicities were studied using the concentration addition model (isobolograms and toxic unit summation), and the mixture toxicity index (MTI). The ZPT-CPT combination had a strictly synergistic effect which requires attention because the coexistence of ZPT and CPT in the marine environment, due to transchelation of ZPT, may occur. The binary mixtures of Diuron with the metal pyrithiones exhibited various interactive effects (synergistic, antagonistic or additive) depending on concentration ratios, whereas all binary mixtures that contained Chlorothalonil exhibited antagonistic effects. The different types of combined effects subsequent to proportion variation of binary mixtures underline the importance of the combined toxicity characterization for various ratios of concentrations. The four ternary mixtures tested, also exhibited various interactive effects, and the quaternary mixture exhibited synergism. The models applied were in agreement in most cases. The observed synergistic interactions underline the requirement to review water quality guidelines, which are likely underestimating the adverse combined effects of these chemicals.     

Organ and effective dose evaluation in diagnostic radiology based on in-phantom dose measurements with novel photodiode-dosemeters

Organ and the effective doses of patients undergoing clinical X ray examinations of chest and abdomen were evaluated with an anthropomorphic phantom and a new dosimetry system. The system was comprised of 34 pin photodiode dosemeters placed in/on particular tissues or organs of the anthropomorphic phantom, where the tissues and organs are defined by the International Commission on Radiological Protection (ICRP) to estimate the effective doses. Dosemeter signals were acquired on a personal computer directly, and converted into absorbed doses, from which the organ and the effective doses were evaluated on the computer. Our study showed that organ doses ranged from <0.01 to 0.72 mGy in routine X-ray radiography of chest and of abdomen and from 0.07 to 55.91 mGy in routine computed tomography (CT) examinations with current multi-slice CT scanners. The effective dose observed in the chest CT examination was approximately 300 times higher than that in chest radiography.     

Great earthquake East Japan observation by superconducting gravimeter in Antarctica

The seismic wave caused by the Great East Japan Earthquake that occurred on March 11, 2011 at 14:46 JST (magnitude: M 9.0, location: 38° 6.2 min N, 142° 51.6 min E, depth: 32 km) was clearly observed approximately 20 min later by the superconducting gravimeter at Syowa Station, about 14,000 km away from Japan. The observation of the free oscillations of the Earth will be reported compared to the observed records of the Sumatra earthquake on December 26, 2004 (magnitude: M 9.1) and Chile earthquake on February 27, 2010 (magnitude: M 8.8).     

Percolation threshold for electrical resistivity of Ag-nanoparticle/titania composite thin films fabricated using molecular precursor method

To find the percolation threshold for the electrical resistivity of metallic Ag-nanoparticle/titania composite thin films, Ag-NP/titania composite thin films, with different volumetric fractions of silver (0.26 ≤ φ_Ag ≤ 0.68) to titania, were fabricated on a quartz glass substrate at 600 °C using the molecular precursor method. Respective precursor solutions for Ag-nanoparticles and titania were prepared from Ag salt and a titanium complex. The resistivity of the films was of the order of 10⁻² to 10⁻⁵ Ω cm with film thicknesses in the range 100–260 nm. The percolation threshold was identified at a φ_Ag value of 0.30. The lowest electrical resistivity of 10⁻⁵ Ω cm at 25 °C was recorded for the composite with the Ag fraction, φ_Ag, of 0.55. X-ray diffraction (XRD), field-emission scanning electron microscope (FE-SEM), and transmission electron microscopic (TEM) evaluation of the effect of the morphology and the nanostructures of the Ag nanoparticles in the composite thin films on the electrical resistivity of the film revealed that the films consist of rutile, anatase, and metallic Ag nanoparticles homogeneously distributed in the titania matrix. It could be deduced that the electrical resistivity of the thin films formed at 600 °C was unaffected by the anatase/rutile content within the thin film, whereas the shape, size, and separation distance of the Ag nanoparticles strongly influenced the electrical resistivity of the Ag-nanoparticle/titania composite thin films.     

Fermentation-induced changes in the concentrations of organic acids,amino acids,sugars, and minerals and superoxide dismutase-like activity in tomato vinegar

Various raw materials are used to produce vinegars that contain functional compounds associated with disease prevention. We evaluated changes in functional compounds during tomato vinegar production and superoxide dismutase-like activity of tomato vinegar. Tomato vinegar contained abundant anti-hypertensive compounds, e.g., γ-aminobutyric acid and potassium derived from tomatoes and acetic acid and pyroglutamic acid produced during fermentation. It had stronger superoxide dismutase-like activity than commercial vinegars because of tomato-derived superoxide dismutase-like compounds, including phenolic acids, flavonoids, and glutathione. These data indicate that tomato vinegar is a candidate dietary supplement with potential preventive effects against cardiovascular diseases due to its anti-hypertensive and superoxide dismutase-like compounds.