Fabrication of TiO2-based transparent conducting oxide on glass and polyimide substrates

We report on preparation and properties of anatase Nb-doped TiO₂ transparent conducting oxide films on glass and polyimide substrates. Amorphous Ti_0.96Nb_0.04O₂ films were deposited at room temperature by using sputtering, and were then crystallized through annealing under reducing atmosphere. Use of a seed layer substantially improved the crystallinity and resistivity (ρ) of the films. We attained ρ = 9.2 × 10^− 4 Ω cm and transmittance of ~ 70% in the visible region on glass by annealing at 300 °C in vacuum. The minimum ρ of 7.0 × 10^− 4 Ω cm was obtained by 400 °C annealing in pure H₂.     

Variation,Modification and Engineering of Lipid A in Endotoxin of Gram-Negative Bacteria

Lipid A of Gram-negative bacteria is known to represent a central role for the immunological activity of endotoxin. Chemical structure and biosynthetic pathways as well as specific receptors on phagocytic cells had been clarified by the beginning of the 21st century. Although the lipid A of enterobacteria including Escherichia coli share a common structure, other Gram-negative bacteria belonging to various classes of the phylum Proteobacteria and other taxonomical groups show wide variety of lipid A structure with relatively decreased endotoxic activity compared to that of E. coli. The structural diversity is produced from the difference of chain length of 3-hydroxy fatty acids and non-hydroxy fatty acids linked to their hydroxyl groups. In some bacteria, glucosamine in the backbone is substituted by another amino sugar, or phosphate groups bound to the backbone are modified. The variation of structure is also introduced by the enzymes that can modify electrostatic charges or acylation profiles of lipid A during or after its synthesis. Furthermore, lipid A structure can be artificially modified or engineered by the disruption and introduction of biosynthetic genes especially those of acyltransferases. These technologies may produce novel vaccine adjuvants or antagonistic drugs derived from endotoxin in the future.     

Soil stiffness as a function of dry density and the degree of saturation for compaction control

A data set of the coefficient of vertical subgrade reaction for a plate diameter of 30 cm, K_P.FWD, measured by Portable Falling Weight Deflectometer tests in full-scale compaction tests on sandy soil using various types of compaction machines was analysed. Based on this analysis and the previous analysis of a CBR data set from another full-scale compaction test series, a set of conclusions could be drawn. The soil stiffness indexes (SSIs), CBR and K_P.FWD, can be expressed by, respectively, an empirical equation multiplying a function of ρ_d and another of S_r, where CBR and K_P.FWD decrease significantly as S_r increases. As such, ρ_d values cannot be estimated from SSI alone. By fixing the field ρ_d – w compaction curve by keeping the soil type and the field compaction energy level, CEL_f, to those in the field compaction tests in which the SSI – ρ_d – S_r correlation has been calibrated, field compacted ρ_d & w states can be estimated by measuring the SSI values. Then, by the upper-bound and lower-bound control of SSI, the field compacted states approach the specified target, where, typically, ρ_d = the maximum dry density for CEL_f and S_r = the optimum degree of saturation, (S_r)_opt. A method to incorporate this indirect but fast SSI-based compaction control into the conventional ρ_d & w-based compaction control is proposed.     

Recent developments of shearing in Japan

In this article, leading research and development activities of shearing in Japan are reviewed. Main contents are elucidation of shearing mechanism, theoretical analysis, tool life, burr-free blanking, precision shearing, bar cropping, pipe cutting, slitting, shearing of non-metallic materials, tool making, shearing of extremely thin sheets, etc.     

Electronic structures of polyacenacene and polyphenanthrophen anthrene. Design of one-dimensional graphite

The electronic structures of polyacenacene (PAA) and its geometrical isomer, polyphenanthrophenanthrene (PPhP) have been studied using the tight-binding SCF-CO (self consistent field-crystal orbital) method with respect to a design of one-dimensional (1D) graphite. The geometry of each polymer is optimized from the energetic point of view. It has been found that from the analysis of the electronic structure of its optimized geometry, PAA favours the structure without the carbon-carbon bond alternations, yielding no band gap. In this sense, PAA is a typical 1D-graphite. On the other hand, it is predicted that the magnitude of the band gap of PPhP in its optimized geometry is almost equal to that of trans-polyacetylene.     

Preparation of Fe-Al Binary System Intermetallic Compounds by Multi-Layered Roll-Bonding

Iron aluminides exhibit good resistance to high-temperature sulfidizing and oxidizing environments and potential for structural applications at high temperatures under corrosive environments. In this study, Fe-Al intermetallic compound was prepared by multi-layered roll-bonding of elemental Fe and Al foils. The process consisted of the accumulative roll-bonding (ARB) for making a laminated Fe/Al sheet and the subsequent heat treatment promoting a solid phase reaction in the laminated Fe/Al sheet. The microstructures produced at each processing stage were characterized by optical microscopy and scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS). Vickers microhardness testing was used for hardness determination. A homogeneous intermetallic compound of Fe3Al or FeAl could be obtained after the subsequent heat treatment for 1.8 ks at 973 K and for 10.8 ks at 1123 or 1173 K.     

Synthesis of NAD polystyrene microspheres and application as a carrier of glucoamyrase immobilization

Polystyrene microspheres with a small amount of acrylic acid (200 : 1) incorporated were synthesized by nonaqueous phase dispersion (NAD) polymerization to investigate the feasibility of use as a carrier for immobilized enzyme. Seeded emulsion polymerization was then carried out to obtain larger cross-linked polystyrene spheres, the structure of which was expected to yield a favorable environment to keep the original activity of the immobilized enzyme. Glucoamylase, a particular enzyme catalyzing the hydrolysis of oligosaccharides to glucose, was immobilized through peptide bonding using a carbodiimide activating agent. Thirty percent of the enzyme activity at maximum was retained relative to free glucoamylase. The immobilized enzyme remained active after 4 months, although its poor resistance to heat was not improved. © 1994 John Wiley & Sons, Inc.     

Automated synthesis of radiopharmaceuticals for positron emission tomography: an apparatus for [1-11C] labeled carboxylic acid

A fully automated apparatus for the synthesis and formulation of short-lived ¹¹C (t_1/2 = 20 min)-labeled carboxylic acids for positron emission tomograpy (PET) has been developed. Injectable solutions of [1-¹¹C]acetic acid, [1-¹¹C]octanoic acid and [1-¹¹C]palmitic acid wilh radioactivities of 6.36-8.29 GBq, 0.070-1.43 GBq and 0.42-0.89 GBq were obtained. The preparation time was under 40 min after the end of bombardment. An automatic washing function means that labeled compound of the same or different kinds can be produced several times a day without any maintenance of the system. The control system is sited away from the ‘hot laboratory’, so operator exposure to radiation is minimized.