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Graphical abstractDisplay Omitted We have developed and evaluated a PMMA-based gas sensor for monitoring VOCs.The sensor consists of a PMMA cantilever, a PVDF piezoelectric film and a PBD.The sensor had a resonant frequency of 341kHz and quality factor of 71.We examined the resonant frequency shift by setting up a VOC dilution flow system.The resonant frequency shifted when the sensor was exposed to toluene vapor. We have developed and evaluated a PMMA-based gas sensor to realize a low-cost sensor network system for monitoring VOCs (volatile organic compounds). The PMMA-based gas sensor consists of a PMMA (poly methyl methacrylate) cantilever, a piezoelectric film of PVDF (polyvinylidene fluoride), and a thin film of PBD (polybutadiene). We began by investigating the influence of PBD coating of a dynamic property of the PMMA cantilever in a higher order resonance mode under atmospheric pressure at room temperature. The PBD-coated PMMA cantilever had a resonant frequency of 341kHz and quality factor of 71 at the 4th flexural vibration mode. Next, we examined the change of resonance frequency in the presence of toluene vapor by setting up a gas sensor evaluation system equipped with a VOC dilution flow system, temperature-controlled chamber, oscillation circuit, and frequency counter. The resonant frequency shifted when the PMMA-based gas sensor was exposed to toluene vapor. The measured toluene sensitivity in the experiment was 0.02Hz/ppm.

We have developed and evaluated a Polymer-based VOC (volatile organic compounds) sensor module to realize a low-cost wireless sensor network system for environmental monitoring. The polymer-based VOC sensor module consists of a polymer- based VOC sensor, a sensing circuit, a transmitter and a receiver. The polymer-based VOC sensor composed polycarbonate (PC) cantilevers with PVDF (polyvinylidene fluoride) piezoelectric films. We examined the change of resonance frequency in the presence of VOC vapor by setting up a resonant sensor evaluation system equipped with a VOC dilution flow system and temperature-controlled chamber. The resonant frequency of polymer-based VOC sensor shifted significantly downward during the toluene, octane and ethanol exposure. The resonant frequency was converted to I2C output signal by I2C-I/F and transmitted to receiver

We investigated the size and mode dependencies of the resonance frequencies and quality factors of PMMA (polymethyl methacrylate) and PC (polycarbonate) cantilevers under atmospheric pressure in order to obtain fundamental data for polymer-based VOC (volatile organic compound) sensors. PMMA cantilevers and PC cantilevers are fabricated by hot embossing, bonding, and polishing techniques. Variations in the vibration mode result in large variations in the resonance frequencies and quality factors of these cantilevers. The measured resonance frequencies correlated well with the theoretical undamped resonance frequency of a flexural-vibrating cantilever. The measured quality factors varied from 10 to more than 100, depending on the vibration mode. A higher mode tended to exhibit a higher quality factor.

The mode dependences of resonance frequencies and quality factors in a PMMA (polymethyl methacrylate) cantilever and a PC (Polycarbonate) cantilever at atmospheric pressure are investigated to obtain fundamental data for polymer-based VOC (volatile organic compounds) sensors. The PMMA cantilever and the PC cantilever are fabricated using hot embossing, bonding and polishing techniques. The resonance frequencies and the quality factors are found to vary largely depending on the vibration mode. The measured resonance frequencies correlate well with the theory of undamped resonance frequency of a flexural-vibrating cantilever. The measured quality factors varied from less than 20 to more than 100 depending on the vibration mode. A higher mode tended to exhibit a higher quality factor. The highest quality factor of 100 was obtained on the 4th flexural mode in both the PMMA and PC cantilever.

The work was carried out to get information how to use wasted biomass, particularly waste woods, as a raw material for fine and advanced carbon products. A phenol-starch-formaldehyde resin was synthesized by using phenol of which one third was replaced by cornstarch as a model material for waste wood. The resin was spun, stabilized and finally carbonized at 900°C. A commercial novolac-type phenol-formaldehyde resin was used as a reference. There was no essential difference in the microscopic structures between the carbon fibers derived from the synthesized and the commercial resins, but the former resin showed some disadvantages against the latter: one is a poor spinnability to result in thick and irregular carbon fibers, and another one is the formation of macropores in the resulting carbon fibers, leading to low mechanical strength. These disadvantages are thought to be caused by the remaining MgO particles used as a neutralization agent in the synthesis of the resin. A possibility to achieve the final purpose is discussed briefly.

In this paper, the effects of oscillation amplitude on the aerodynamic derivatives of the thin rectangular cylinder with B/D = 13 and 150 were investigated. It was clear that the torsional amplitude affected strongly the aerodynamic derivatives H* 2 and A* 2 . This effect reduced the critical velocity of flutter by about 10%. The cause of this effect was investigated by the measurement of the unsteady surface pressure. This investigation made it clear that the variation of A* 2 is caused by the movement of the acting point of the resultant lift force. These results indicate that these effects cannot be disregarded for such a simple thin plate but for a real bridge girder with a more complex cross-section and with delicate aerodynamic control devices.

We have developed and evaluated polycarbonate (PC)-based dual cantilever sensors as part of a low-cost sensor network system for monitoring VOCs (volatile organic compounds). The PC-based dual cantilever sensor consists of a PC cantilever and a PBD (polybutadiene)-coated PC cantilever with PVDF (polyvinylidene fluoride) piezoelectric films. We began by investigating the size and mode dependences of resonant frequencies and quality factors of PC cantilevers and PBD-coated PC cantilever as output signal of PVDF piezoelectric film. Next, we examined the change of resonance frequency in the presence of VOCs vapor by setting up a resonance sensor evaluation system equipped with a dilution flow system, temperature-controlled chamber, oscillation circuit, and frequency counter. The resonant frequency of both PC cantilever and PBD-coated PC cantilever shifted significantly downward depending VOCs.

Birch wood meals, phenolated in the presence of sulfuric acid as catalyst, were compression-molded by using hexamethylenetetramine (HTMA) as a curing agent. The effect of combined phenol on the flexural strength and modulus of elasticity (MOE), Brinell hardness, and water resistance of the phenolated-wood-based moldings was studied. Moreover, on the basis of several factors, we examined the dynamic mechanical behaviour of the moldings using a dynamic mechanical thermal analyzer (DMTA). The flexural strength, MOE, hardness, and water resistance of the moldings were found to be controlled by the amount of combined phenol and at sufficient combined phenol levels were comparable to those of a commercial novolak-resin-based molding. Additionally, the DMTA studies showed that the temperature dependence of the dynamic elastic modulus (E') of phenolated-wood-based moldings depends greatly on the amount of combined phenol, filler content, HMTA content, molding temperature, moisture content, water-immersion test, heat-aging time, and frequency, and at sufficient combined phenol levels was comparable to that of the commercial novolak-resin-based material. It could also be stated that phenolated-wood-based moldings could be used safely within a temperature range of 75°C-165°C, depending upon the amount of combined phenol. Furthermore, the biodegradability of the phenolated-wood-based moldings was greater than that of a commercial novolak-resin-based molding.

With about 1000-h of relativistic high-energy ion beams provided by Heavy Ion Medical Accelerator in Chiba, about 70 users are performing various biology experiments every year. A rich variety of ion species from hydrogen to xenon ions with a dose rate of several Gy/min is available. Carbon, iron, silicon, helium, neon, argon, hydrogen, and oxygen ions were utilized between 2012 and 2014. Presently, three electron cyclotron resonance ion sources (ECRISs) and one Penning ion source are available. Especially, the two frequency heating techniques have improved the performance of an 18 GHz ECRIS. The results have satisfied most requirements for life-science studies. In addition, this improved performance has realized a feasible solution for similar biology experiments with a hospital-specified accelerator complex.

Radiative recombination properties of excitons have been investigated for a GaAs quantum well confined by barriers with an energy gap slightly larger than the energy of the first excited (n = 2) subband exciton. The low-temperature photoluminescence (PL) spectra show a surprisingly intense emission line higher in energy and intensity than the ground-state exciton band. This high-energy PL line remains prominent for excitation power densities between 0.01 and 10 W/cm/sup 2/. It can be clearly discriminated from the barrier emission using PL excitation (PLE) spectra and calculations of the subband energies. The picosecond PL dynamics reveal that the high-energy PL line exhibits a decay time of 0.77 ns at 20 K, which is much longer than the expected carrier relaxation time. These results indicate that the high-energy PL line can be ascribed to the exciton population of the first excited subband, which is stabilized for certain barrier injection conditions due to the exciton-parity forbidden relaxation (from n - 2 to n = 1 excitons) pathway.

The feasibility of F/sub 2/ lithography (VUV lithography) was discussed positively from a viewpoint of optical materials and mask materials. The laser durability of CaF/sub 2/ and new materials for the F/sub 2/ mask substrate are discussed.

We demonstrate the imaging of buried features in a microstructure—a tiny hole in an aluminum thin film covered by a chromium layer—with nanometer lateral resolution using a transient temperature distribution restricted to within ~0.5 µm of the sample surface. This is achieved by mapping photothermally induced megahertz surface vibrations in an atomic force microscope. Local thermal probing with megahertz-frequency thermal waves is thus shown to be a viable method for imaging subsurface thermal features at submicron depths. ©2003 American Institute of Physics.

Summary form only given. ArF lithography (wavelength 193 nm) is expected to start its mass-production stage at this time. It will cover the 100 nm resolution node and will extend to near 80 nm. F2 lithography (wavelength 157 nm) is expected to come next; it is the technology that realizes both high throughput (comparable to ArF) and high resolution below 70 nm at the same time. F2 exposure tools have similar structure to ArF tools; but there are significant differences in optics, materials and mechanical structures.

Optical heterodyne force microscopy (OHFM) is a novel local probe microscopy that combines an atomic force microscope (AFM) with a periodically modulated laser source. The amplitude and phase of the vibrations of the sample surface induced by the periodic heating can be imaged with OHFM. The thermal diffusivity, rather that just the thermal conductivity, has a significant effect on the image contrast. Surface and subsurface variations in thermal properties can be mapped to depths of the order of the thermal diffusion length, which decreases as the modulation frequency increases. The use of an incident laser beam chopped at megahertz frequencies typically allows ∼1 μm lateral or depth resolution in thermal properties. However, the thermal near field can be imaged to a lateral resolution of that of the AFM, namely a few nanometers. In this study we have detected a buried aluminum film with OHFM and done quantitative comparisons with a one-dimensional theoretical model based on the thermal wave propagation i...

Cobalt 60 gamma and electron beam irradiation have been studied for the grafting of methacrylic acid in aqueous solution to cotton fabric. Dose rate effects led to greater degrees of grafting with gamma radiation. Doses higher than one or five megarads for gamma and electron beam irradiations, respectively, caused some degradation of the grafted side chains. The effect of monomer concentration was also investigated, high concentrations led to lower yields; this was ascribed to poorer penetration of the monomer solution into the fabric at lower water constants. The addition of small amounts of ethylene glycol dimethacrylate gave higher graft efficiencies due to crosslinking. Excellent yields and efficiencies were obtained under optimum conditions. The grafted products will have higher hydrophillicity and also ion exchange capacity compared with the original cotton fabric.

Cobalt 60 γ and electron beam radiation were used to graft diethylphosphatoethyl methacrylate, pure and in 90:10 methanol solution, to cotton cloth. This monomer, with an 11.64% phosphorus content, was especially developed by the Scott Paper Co. to develop fire retardancy. A simple pad and squeeze application followed by direct irradiation under a nitrogen atmosphere was used. Although excess monomer could be removed by washing with water, no solvent for the polymer was found so only the total “add-ons” could be measured. With 60 Co irradiation, total polymerization was obtained with more than 1 Mrad but with electron beam irradiation only about 50% conversion was obtained even with 10 Mrad. No acceleration in the rates could be achieved with the viscous pure monomer as opposed to in solution. Yields adequate to impart reasonable fire retardancy could, however, be obtained with about 3 Mrad with electrons. No noticeable degradation of the polymer occured at the doses used.