Biodegradation of poly(3-methoxy-4-hydroxy styrene)

Poly(3-methoxy-4-hydroxy styrene) (MHS) was prepared as a biodegradable polymer; it offers a simplified model of naturally biodegradable polymers related to softwood lignin, having pendant guaiacyl groups. This polymer was decomposed by microorganisms in soil, and four intermediates were identified in the degradation pathway. Judging from the identified intermediates, vanillic acid seems to be the first biodegradation product of polyMHS in the pathway. The ring cleavage of vanillic acid gives rise to monomethyl ester of β-carboxymuconic acid, discovered as an intermediate in the degradation pathway. Monomethyl ester of β-carboxymuconic acid, which was isolated and characterized, is decomposed to maleic and oxalic acids by microorganisms which are essential for utilization of guaiacyl group. Elucidation of the degradation pathway of polyMHS revealed that the step reactions responsible for the conversion of this compound to maleic and oxalic acids are somewhat similar to the step reactions responsible for the degradation of lignin by microorganisms.     

Development of one pass sea water reverse osmosis module “Hollosep”

CTA hollow fiber membranes with high performance, especially high salt rejection, have been developed for one pass sea water desalination by reverse osmosis.Performances of modules have been studied relating to sea water desalination and are discussed in terms of hollow fiber membrane and module configuration.High salt rejection makes it possible to operate under severe operating conditions of high product water recovery and high salinity sea water.Operating costs are discussed with regard to product water recovery.     

Fabrication of ultrathin and highly uniform silicon on insulator by numerically controlled plasma chemical vaporization machining

Metal-oxide semiconductor field-effect transistors fabricated on a silicon-on-insulator (SOI) wafer operate faster and at a lower power than those fabricated on a bulk silicon wafer. Scaling down, which improves their performances, demands thinner SOI wafers. In this article, improvement on the thinning of SOI wafers by numerically controlled plasma chemical vaporization machining (PCVM) is described. PCVM is a gas-phase chemical etching method in which reactive species generated in atmospheric-pressure plasma are used. Some factors affecting uniformity are investigated and methods for improvements are presented. As a result of thinning a commercial 8 in. SOI wafer, the initial SOI layer thickness of 97.5+/-4.7 nm was successfully thinned and made uniform at 7.5+/-1.5 nm.     

Adhesion control of fungal spores on solid surfaces using hydrophilic nanoparticles

Mold growth can trigger a variety of serious problems such as allergies and asthma. Designing surfaces that are unfavorable for the adhesion of fungal spores is considered an effective method to prevent fungal growth. In this study, the effect of hydrophilic surface treatment on the adhesion of fungal spores onto substrates was investigated using Aspergillus oryzae as a model fungus. The fungal spores that strongly adhered on the hydrophilic substrates under atmospheric conditions were easily removed by lightly washing by hand in water. These experimental results agreed well with thermodynamic predictions based on contact angle measurements. In addition, the removal ratio of the fungal spores on substrates coated with silica nanoparticles was higher than that on plasma-treated glass. It is believed that the contact area between a spore and substrate depended on the substrate roughness. Atomic force microscopy revealed that there was almost no adhesive force between the spores and glass substrate coated with silica nanoparticles. These results suggest that hydrophilic treatment using hydrophilic silica nanoparticles is more effective than hydrophilic plasma treatment to prevent fungal spore adhesion on glass substrates.     

关西国家图书馆

乍看起来，大体量的日本关西国家图书馆并不是非常引人注目，该馆的馆藏能力达到2000万册，目前尚有大量空间可以利用，图书馆最初设在东京，但是由于首都地价过高，因此在那里进行扩建或是重修图书馆的工作是不可能的。     

Removal properties of low-thermal-expansion materials with rotating-sphere elastic emission machining

Optical mirrors used in extreme ultraviolet lithography systems require a figure accuracy and a roughness of about 0.1 nm rms. In addition, mirror substrates must be low-thermal-expansion materials. Thus, in this study, we processed two low-thermal-expansion materials, ULE [K. Hrdina, B. Hanson, P. Fenn, R. Sabia, Proc. SPIE 4688 (2002) 454.] (Corning Inc.) and Zerodur [I. Mitra, M.J. Davis, J. Alkemper, Rolf Müller, H. Kohlmann, L. Aschke, E. Mörsen, S. Ritter, H. Hack, W. Pannhorst, Proc. SPIE 4688 (2002) 462.] (SCHOTT AG), with elastic emission machining (EEM) in order to evaluate the removal properties. Consequently, we successfully calculated the respective removal rates, because removal volumes were found to be proportional to process times in EEM. Moreover, we demonstrated that the surface roughness of Zerodur is reduced to 0.1 nm rms in the spatial wavelength range from 100 μm to 1 mm.     

Domain switching characteristics of lead zirconate titanate piezoelectric ceramics during mechanical compressive loading

To better understand the domain switching characteristics of lead zirconate titanate (PZT) ceramics, the orientations of domains have been directly investigated during loading and unloading using various experimental techniques. Upon loading, linear and non-linear fracture mechanics of the PZT ceramics are observed. The slope of the stress–strain response is attributed mainly to lattice strain and domain switching strain. During the loading process, electrical activity also occurs several times in the PZT ceramics. This activity is related to a lightning-like phenomenon and consists of a bright flash with a click. This electrogenerative event is caused by severe domain switching. The characteristics of domain switching and reverse switching are detected during the loading and unloading processes. The amount of domain switching depends on the grain, due to different stress levels. In addition, two patterns of 90° domain switching systems are characterized, namely (i) 90° turn about the tetragonal c-axis and (ii) 90° rotation of the tetragonal a-axis.     

An etching characterization method for revealing the plastic deformation zone in a SUS303 stainless steel

Etching characteristics used to reveal localized plastic deformation zones in a SUS303 stainless steel have been examined. The etching was conducted on a sample using an etchant consisting of 5-g ferric chloride, 50-mL hydrochloric acid, and 100-mL water. The sample was deformed severely and heated to various temperatures before the etching process. With this etching technique, the plastically deformed area is clearly observed even at low magnification. This is due to a change of the microstructural characteristics in the plastic deformation zone. There are different microstructure patterns that reveal the plastic zone in the sample with and without heating, e.g., plastic zone in the sample with heating to 800 °C is observed clearly due to randomly oriented crystals and recrystallized small grains with precipitated nano-size particles. Details of the etching characteristics that reveal the plastic deformation zone are further discussed.