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On March 11, 2011, a massive earthquake with a magnitude of 9.0 struck Sanriku Coast, Japan. The ensuing tsunami swept across many cities and villages along the Pacific coast of the Tohoku district, causing tremendous human and structural damage. These disasters gave a good chance to review the relationship between infrastructures and sustainability in Japan from the viewpoints of concrete structures and concrete-polymer composites. The article introduces essential defects of cement concrete structures and discusses different state-of-the-art concrete-polymer composites and the properties of ultra high strength fiber reinforced concrete.

Pt wires were fabricated by using electron-beam (EB) and Ga focused-ion-beam (FIB) irradiation while providing C5H5Pt(CH3)3 gas through a nozzle. Electron transport properties of the wires were investigated. The resistance of the EB-deposited wires was quite high as deposited but was reduced by 3-4 orders of magnitude after 400-500°C annealing. The electron transport of the as-deposited EB-deposited wire was dominated by the variable range hopping and the Coulomb blockade simultaneously, and showed the antilocalization effect after 400°C annealing. The electron phase-breaking length in the EB-deposited wire with 400°C annealing, which was derived from a theoretical fitting, is ≈10 nm at ≈4 K and increases with decreasing temperature. This means that 10-nm fabrication technology and improvement of coherence length are required for coherent vacuum nanoelectronics.

Randomly cross-linked homopolymer networks of 2-(dimethylamino)ethyl methacrylate (DMAEMA) of various average degrees of polymerization (DPs) between cross-links were synthesized by group transfer polymerization (GTP) in tetrahydrofuran (THF), using 1-methoxy-1-(trimethylsiloxy)-2-methyl propene (MTS) as the initiator, ethylene glycol dimethacrylate (EGDMA) as the cross-linker (eightfold molar excess with respect to the initiator), and tetrabutylammonium bibenzoate (TBABB) as the catalyst. Networks with monomer-to-initiator molar ratios of 5, 10, 20, 50, 100 and 200 were synthesized successfully, while an attempted synthesis with a monomer-to-initiator molar ratio of 500 did not produce a network. The networks were characterized in terms of their degree of swelling (DS) in water and the effects of DP, pH, salt concentration and temperature were investigated. Moreover, the aqueous degrees of swelling determined in this study of random networks were compared to the aqueous degrees of swelling of model networks also synthesized by GTP and using a similar procedure.

Group transfer polymerization was used to synthesize several series of hydrophilic random and model networks. Cationic random networks were prepared both in bulk and in tetrahydrofuran (THF) using a monofunctional initiator and simultaneous polymerization of monomer and branch units, while a bifunctional initiator was employed in THF for the synthesis of model networks comprising basic or acidic chains. Upon polymerization of the monomer, the latter initiator gives linear polymer chains with two living ends, which are subsequently interconnected to a polymer network by the addition of a branch unit. Homopolymer network star polymers were also synthesized in THF by a one-pot procedure. The synthesis involved the use of a monofunctional initiator and the four-step addition of the following reagents: (i) monomer, to give linear homopolymers; (ii) branch unit, to form arm-first star polymers; (iii) monomer, to form secondary arms and give in-out star polymers; and, finally (iv) branch unit again, to interconnect the in-out stars to networks. Different networks were prepared for which the degree of polymerization (DP) of the linear chains between junction points was varied systematically. For all networks synthesized, the linear segments, the arm-first and the in-out stars were characterized in terms of their molecular weight (MW) and molecular weight distribution (MWD) using gel permeation chromatography (GPC). The degrees of swelling of both the random and model networks in water were measured and the effects of DP, pH, and monomer type were investigated.

The densification mechanism of borosilicate glass, silica gel and amorphous titania powders by hydrothermal hot-pressing is described. The glass powders were densified by a viscous flow mechanism, ...

A series of hydrophilic model networks based on homopolymers of a weak base were prepared using group transfer polymerization (GTP) and characterized in terms of their aqueous degree of swelling as a function of pH. This constitutes the first reported example of cationic hydrogels in which the length of segments between cross-links is kept constant. The synthesis involved the GTP of 2-(dimethylamino)ethyl methacrylate (DMAEMA, weak base monomer) in tetrahydrofuran (THF, solvent) using the bifunctional initiator, 1,4-bis(methoxytrimethylsiloxymethylene)-cyclohexane (MTSMC) and the subsequent in situ cross-linking with the addition of 8-fold mole excess with respect to the initiator of the difunctional monomer ethyleneglycol dimethacrylate (EGDMA). Four different model networks with degrees of polymerization (DP) of the linear segments between cross-links of 10, 20, 50 and 100 were prepared. The molecular weight (MW) and molecular weight distribution (MWD) of the linear segments were measured using gel permeation chromatography (GPC) in THF. The degree of swelling of all model networks was measured in water as a function of the solution pH. The conditions of gel synthesis were optimized with respect to cross-linker loading and monomer concentration using the results of a parallel study on the synthesis of star polymers of DMAEMA. The star polymers were also prepared by GTP of DMAEMA and linking (to stars) with EGDMA, but a monofunctional initiator, 1-methoxy-1-trimethylsiloxy-1-methyl-propene (MTS), was used rather than MTSMC. The star polymers were analyzed by GPC which revealed the percentage of free homopolymer relative to star polymer. The optimal conditions were identified as those under which the percentage of unlinked (free) homopolymer is minimized — the same conditions were adopted for the synthesis of the networks.

Hydrothermal hot-pressing (HHP) technique was used to solidify calcium silicate hydrate (xonotlite) powders at a relatively low temperature (150°C) and low pressure (20 MPa) with short reaction times (10–30 min). Chitosan was used to reinforce the mechanical strength of the hydrothermally hot pressed calcium silicate compacts. The tensile strength of the solidified compacts with and without chitosan was tested. The ultimate strength of the chitosan–xonotlite composite reached approximately 12 MPa for 5 wt.% chitosan content, which is almost six times larger than its non-additive compact. Additives had no effect to the apparent density of the solidified bodies, which remains almost constant at ∼2 g cm −3 , similar to that of the non-additive compacts. The low temperature solidification method is expected to be useful in the development of an environment-friendly processing route for making artificial wood.

Hydrothermal hot-pressing (HHP) technique was used to solidify calcium silicate hydrate powders at a relatively low temperature as 200°C and low pressure (20 MPa) with short reaction time (30 min). Diatomaceous earth, α-quartz, fly ash and silicic acid were used as the Si sources. Waste rice husk was used for fiber reinforcement to strength the hydrothermal hot pressed calcium silicate compacts. The tensile strength of the solidified bodies with and without rice husk was tested. The solidified bodies with reinforced by 5% rice husk exhibit high tensile strength (∼9 MPa), which is almost three times lager than their non-additives compacts. There is no effect of additives for the density of solidified bodies, which remains almost constant at ∼2gcm–3 similar to their non-additive compacts. The developed low temperature solidification method is expected to be useful in the development of an environmentally friendly processing route for making artificial wood.

Hydrothermal hot-pressing (HHP) technique was used to solidify shell powder dyed. Shell powder was mixed with dye with a ratio of 0.25 wt%, and was treated by HHP at 130 to 170° C, 45 MPa for 2 hours. It is showed that the powder can be dyed well by some basic dyes at 60° C, and can maintain the color of dyes after HHP process. The resulting compactness with a beautiful color appearance has high hardness and apparent density. Possible mechanisms for solidification and coloration were also discussed.

A new metastable superconductor with nominal composition of Li 2 Na 1 N y C 60 ( y unknown) is prepared by thermal decomposition of lithium azide (LiN 3 ) and sodium azide (NaN 3 ). It is suggested that the superconducting phase in this compound is created by intercalation of the neutral spacer such as NaN 3 . The supeconductivity is examined by a low-field signal of microwave absorption (LFS) and by SQUID. The critical temperature is estimated to be 12 K from SQUID and 14 K from LFS measurement, and the shielding fraction is over 9% at 5 K. Superconducting parameters, such as critical temperature, upper and lower critical fields, coherence length and penetration depth are evaluated and found to be distinct from those in other fulleride superconductors.

Extensive usage of chrysotile asbestos has resulted in the remains of large numbers of chrysotile asbestos‐containing buildings to be surveyed. We have recently developed a simple dyeing method for detecting chrysotile asbestos in building materials, which involves pretreatment with calcium‐chelating agent and dyeing treatment with magnesium‐chelating organic dyes. In this study, we further developed a method which eliminates dyed asbestos substitutes containing magnesium, potentially present in building materials. In the new method, post‐treatment with formic acid was conducted to dissolve the non‐chrysotile asbestos materials in order to delineate dyed chrysotile asbestos. The calcium‐masking process was also shown to be an essential process even when the post‐treatment was conducted. It was shown that the new method developed in this study may enable us to dye chrysotile asbestos only without detecting asbestos substitutes in building materials.

The resistance and electron coherence length of Pt nanowires fabricated using electron beam (EB) induced deposition were investigated. It was shown that post annealing was effective for reducing the resistance of the EB deposited wires. The EB deposited Pt wires after 400/spl deg/C annealing showed positive magnetoresistance at low temperatures due to the weak antilocalization. The obtained phase-breaking lengths from the fitting became about 5 nm at 77 K and 15 nm at 4 K, It indicates that the post annealing process is required for the nanosplit emitter and the nanosplit emitter with a gap size of 12 nm must be operated at 4 K in order to observe the electron interference pattern from the nanosplit emitter. Further investigation with nanosplit-emitters after annealing at lower operation temperatures is in progress.

The influence of the Pt cathode resistance on the field emission properties of field emitters fabricated using electron- or focused-ion beam induced deposition is investigated. In the case of the as deposited Pt field emitters, the slope of Fowler-Nordheim plot changes at a gate voltage of 55 V. On the other hand, the field emitters with annealing does not show the change in the slope of the FN plots. The I-V curve of the unannealed emitters could be fitted to the theoretical curve calculated from the FN theory by the compensation resistance of 1.6 M/spl Omega/. It indicates that this slope change is caused by the voltage drop due to the resistance of the field emitter itself.

Very fine diamond was synthesized under hydrothermal conditions, with new bond formation among diamond particles, in 10M‐NaOH solution at 573K, 1GPa, for 24 hours. This new bonding material is formed by carbonization, from chlorinated hydrocarbon such as dichloromethane and 1,1,1‐trichloroethane, under alkaline hydrothermal conditions. The carbonized material forms a new bond between diamond particles by the release of hydrogen‐chloride using a hydrated diamond powder particle as the starting material. With pellet of compacted diamond, the platy materials were produced. These materials were diamond by micro‐XRD analysis. New growth materials between compacted diamonds, and each diamond particles were bonded. Therefore, it is possible that compacted diamonds is sintered by carbon‐bonds under hydrothermal synthesis. Hydrothermal hot‐pressing is technic that materials as glass, calcium silicate and calcium carbonate is solidified. Compacted materials is deformed under hydrothermal conditions, and materials i...

High power laser irradiation with a stripe beam is the key technology for large diagonal carbon nanotube (CNT) cathode surface treatment. CNT cathodes were fabricated on ITO/glass substrates by screen-printing with conventional organic binder. Screen-printed CNT cathodes were irradiated by KrF (248 nm) and XeCl (308 nm) excimer lasers. The spot shape was adjusted as a spot of 8/spl times/8 mm/sup 2/ or a stripe of 200/spl times/0.4 mm/sup 2/. The stripe beam was irradiated in a step of 0.2, 0.3, 0.4, 0.5 and 0.8 mm. The emission characteristics were measured in a vacuum chamber with a pressure of 10-5 Pa. The emission patterns on a phosphor screen were observed by a CCD camera. The turn-on-field became the lowest with a step of 0.5 mm. The turn-on-field became as low as 0.7 V//spl mu/m and the emission density became as high as 1.5 mA/cm/sup 2/ at a field of 2.5 V//spl mu/m by KrF laser irradiation.

In this study, the thermal annealing effects on a single field emitter from the view point of the leakage current between the gate and cathode were investigated. The emission efficiency and percentage of working nano electron sources fabricated beam assisted processes were improved by thermal annealing. Thus the post annealing after beam-assisted processes is effective in reducing leakage current in nano electron sources.

A waste aqueous emulsion including mineral oil, fatty acids and surfactant was wet oxidized by using both microautoclaves for hydrothermal treatments and the continuous wet oxidation apparatus. The treatment at 300°C for 60 minutes reduced Total Organic Carbon (TOC) in waste oil emulsion by about 90%. IR absorption spectra suggested that a large part of the organic contents in waste oil was decomposed into inorganic matters.

Summary form only given. Copolymerizations of aniline, its derivatives and aminonaphthalene derivatives have been achieved by electrochemical and chemical methods and optical and magnetic properties of the copolymers have been studied. Electrochemical copolymerization of aniline with m- and p-sulfonated anilines in aqueous acidic electrolytes resulted in insoluble polymer films on the indium-tin-oxide anode. The copolymers showed unique change in the absorption spectra with the pH value of immersed aqueous solution as in the case of pure polyaniline. The ESR signal also changed with pH value and these changes of optical and magnetic properties can be attributed to protonation and deprotonation of nitrogen atoms in the main chain as in the case of polyaniline. Antiferromagnetic behaviour of these copolymers was observed in ESR measurements at low temperature region, depending on pH value of aqueous solution of pre-treated. Similar antiferromagnetic behaviour was also observed in some copolymers of aniline with sulfonated aminonaphthalene but not in pure polyaniline.

Pt nanowires were fabricated using electron-beam (EB)- and focused-ion-beam (FIB)-induced deposition. The resistance of the EB-deposited nanowires was high (≈107Ω) as deposited and increased markedly when cooled down. The observed temperature dependence of the resistance of the EB-deposited wires indicates that the electron transport in the wires is dominated by variable range hopping (VRH). Coulomb oscillations were observed at temperatures up to ≈200 K for EB-deposited wires simultaneously with VRH. Postannealing was effective to reduce the resistance. The resistance of the FIB-deposited nanowires, in contrast, hardly depended on temperature. Positive magnetoresistance due to weak antilocalization was observed in the case of the FIB-deposited wires.

Excimer lasers with various wavelengths, power densities and beam profiles, have been used to irradiate to carbon nanotube-cathodes (CNT-cathodes) for field emission displays (FEDs) with large diagonal size. KrF (248 nm) and XeCl (308 nm) lasers were used with average power densities varied from 3 to 9MW∕cm2. The beam shapes of the laser beam were adjusted as a square spot of 8×8mm2 for the KrF laser and a stripe of 180×0.4mm2 for XeCl laser using a beam homogenizer. The emission characteristics of CNT-cathodes were improved after laser irradiation. The turn-on-field became as low as 0.7V∕μm and the emission current density became as high as 1.5mA∕cm2 at an applied field of 2.5V∕μm by KrF laser irradiation with a power density of 4MW∕cm2. Homogeneous emission-site distribution could be obtained by a square beam or a stripe beam processing with steps from 0.2 to 0.5 mm. The emission pattern became more homogeneous with increase in laser power density. The laser processing time for large diagonal sizes usin...

The I-V characteristics of carbon nanotube (CNT) cathodes after laser irradiation in air, N/sub 2/ and O/sub 2/ atmospheres have been compared to investigate the influence of each component of air. The I-V characteristic of CNT cathodes irradiated in O/sub 2/ was drastically improved, while there was almost no improvement in I-V characteristics irradiated in N/sub 2/. The O/sub 2/ pressure dependence during laser irradiation to CNT cathodes was also examined. The emission current density at an applied field of 6.6 V//spl mu/m was increased by a factor of 200 for laser irradiation in air. The emission current was enhanced by a factor of 400 for laser irradiation in 10/sup 5/ Pa of O/sub 2/ and the number of emission sites was drastically increased. The emission current density increased with an increase in pressure. The mechanism for drastic improvement in electron emission by UV laser irradiation is via laser-induced oxidation.

A fabrication process of nanosplit emission sites has been developed with a minimum gap size of 12 nm using beam assisted processing. The electron emission patterns on a phosphor screen from a conventional single emitter and nanosplit emitters with various gap sizes were observed at room temperature and 77 K. The emission patterns from the conventional single emitter had a single spot at all the gate voltages. On the other hand, the emission patterns with two spots and additional spots were observed from the nanosplit emitters at gate voltages close to the turn-on voltages and the two spots became overlapped at a higher gate voltage.

The thermal annealing effects on a single-field emitter fabricated by beam-assisted processing were investigated from the viewpoint of the leakage current between the gate and cathode. The cathode current of the field emitters before annealing did not show a linear dependence in Fowler–Nordheim (FN) plots due to the leakage current. However, the current showed a linear dependence in FN plots at and above 200 °C. Thermal annealing increased the emission efficiency. The maximum efficiency was almost 100% after annealing at 750 °C. The percentage of working nanoelectron sources was also increased by annealing T⩾500°C. The postannealing is effective in reducing the leakage current of the field emitters because of the removal of contaminants arising from the beam-induced process.

Thermal decomposition prosesses of conducting carbonous films prepared by pyrolysis of an organic polymer, poly (hydrazocarbonyl-1,4-phenylenecarbonyl), at various heat treatment temperatures have been investigated using Fourier transform infrared and elemental analysis. The anion doping of carbonous films is sucessfully performed by the electrochemical method and an increase in the conductivity of more than five orders of magnetitude has been observed.

Summary form only given. We have prepared C/sub ax/C/sub 60/ by thermal decomposition of CaN6 and studied the X-evolution of its superconducting properties by low field (LFS) microwave absorption and conventional ESR. Superconducting phase is found at x=5 and also x=6 (with lower fraction) with Tc = 8.4-8.8K. The results of the annealing at different temperature (300-450 /spl deg/C) and of aging effect on the intensity of LFS (and hence the amount of superconducting fraction) and ESR g-value and linewidths are presented. Preliminary results on the C/sub 13/ isotope effect on superconducting T/sub c/ in C/sub a5/C/sub 60/ are also discussed.

A process for continuous hydrothermal hot-pressing has been examined, with the resultant development of a new continuous hydrothermal hot-pressing apparatus. In this study, amorphous siliceous material, slaked lime and pulp fiber were mixed and solidified, at 200°C, to produce a board product. The duration of the hydrothermal hot pressing reaction process was 17 minutes. The bending strength of the board product was high; 11MPa.

By means of low field signal(LFS) of microwave absorption combined with conventional ESR, the evolution of superconducting phase of sodium doped C 60 prepared from sodium azide is studied upon heat treatment. The superconductivity is found to be improved both regarding the superconducting(SC) volume fraction and the critical temperature(Tc) upon low temperature annealing at 200°C. However, the LFS intensity decreased at a rapid rate upon high temperature(350∼400°C) annealing indicating suppression of superconductivity of Na 3 (Na α N β ) y C 60 due to thermally activated decomposition of the spacer cluster Na α N β , which has been tentatively assigned to undecomposed NaN 3 ,(although exact values of α and β are not clear yet). The rate of LFS decrease obeyed Arrhenius relation with the activation energy(Ea)=1.9±0.2eV. The critical temperature Tc is found to decrease smoothly from about 16 K to zero with the rate depending on annealing temperature(T a ), suggesting continuous change of SC composition y, and thus a monotonin decrease of the average lattice constant. Clear correlation between improvement or degradation of the SC phase and the peak-to-peak ESR linewidth at room temperature was observed.

A new process for porous silica production has been developed using a hydrothermal method. Hydrothermally synthesized calcium silicate was used as the starting material in this study, which was produced from a mixture of Ca(OH)2 and amorphous silica (white carbon) under hydrothermal conditions of 140°C and 0.4 MPa, for 8 hours. The calcium silicate was subsequently treated with an acid solution, facilitating the leaching of Ca ions. After washing with pure water, the multant Ca2+ -free silica powder was allowed to dry. The Ca2+ -free silica powder was found to have an amorphous structure, with 0.9 ml/g pore volume, up to 610m2/g BET specific surface area, and an average 5 ∼ 8 nm pore size. Our hydrothermal process is simple and low cost, and is anticipated to have numerous applications to the petrochemical industry.

Superconducting (SC) behavior of Ca doped C 60 prepared by calcium azide thermal decomposition is studied by low-field signal (LFS) microwave absorption and conventional ESR. SC phase is obtained for the sample prepared with nominal composition of Ca 6 C 60 and its volume fraction is significantly enlarged by annealing at 350–400°C for 2 h. It is suggested that the SC compound may have two SC phases with slightly different transition temperatures, T C1 (8.2–8.4 K) and T C2 (8.7–8.8 K). The SC 2 phase with higher T C2 is degraded by annealing at 450–500°C and converts to SC 1 . Degradation of SC 2 at high temperature is interpreted to be caused either by (1) thermal reaction of some intercalated Ca with quartz glass and/or (2) dissociation of (CaN) y or N y clusters in the octahedral sites of the Ca 5 (CaN) y C 60 or Ca 5 N y C 60 lattice.