Acid formation from various sulfonates in a chemical amplification positive resist

The quantum yield for acid generation from alkyl and arylsulfonic acid esters of pyrogallol was measured in resist films composed of a sulfonate, tBOC-BA, and novolak resin. It was found that the quantum yield increases with decreasing molecular size of the sulfonyl group, which can explain the differences in sensitivity of the resist systems. Methanesulfonic acid esters of various phenol derivatives were synthesized to see the effect of backbone structure on the efficiency of acid generation. The sensitivity measurement of resists containing these sulfonates indicates that the number of sulfonyloxy groups bonded to a benzene ring is important. The higher number of the sulfonyloxy groups gives a higher efficiency of acid generation.     

Dual-color operation of a laser diode under current and temperature control

We describe a novel method that operates a laser diode with dual colors. Our system requires no external optical parts but does require current and temperature control. We can use either a single color on a time-sharing basis or dual colors simultaneously. The difference between the wavelengths is -0.6 nm, which is as much as 10 times that generated by current control alone. Temporal stability of the generated two wavelengths and the response time of the wavelength change were confirmed through a number of experiments.     

Electrical responses of chalcogenide films in the photodoping process

The photodoping process in Al/AsS₂/Ag tri-layer films has been studied through measurements of electrical impedance, photodoped-layer thickness, and photocurrent. Frequency dependence of the impedance suggests that the sample under photodoping can be approximated by an equivalent electrical circuit. A thickness of photodoped layers, which is estimated from the impedance, is in agreement with a geometrical thickness measured by an atomic force microscope for chemically etched samples. Under the photodoping (with zero bias voltages), a photocurrent remains constant at ~ 5 pA, and near the completion it increases to ~ 1 nA, which is followed with a gradual decrease. By applying a bias voltage between the top (semi-transparent Al) and bottom (Ag) electrodes, we can change a photodoping rate by an order. This rate change is attributable to the modulation of an effective electric field in the doped layer, which induces the motion of Ag ions.     

Recognition and effective degradation of 17beta-estradiol by anti-estradiol-antibody-immobilized TiO(2) nanoparticles

Polyelectrolyte polyacrylic acid (PAA), used in the chemical modification of titanium dioxide (TiO(2)) nanoparticles, allows TiO(2) nanoparticles to remain in suspension at neutral pH. The anti-17beta-estradiol (E2) antibody was immobilized on PAA-modified TiO(2) (PAA-TiO(2)) nanoparticles via covalent bonding between the carboxylic acid of PAA and the amino group of the antibody. The anti-E2-antibody-immobilized TiO(2) (E2Ab-PAA-TiO(2)) nanoparticles can form a suspension at neutral pH, with a particle size of less than 100 nm. The E2-PAA-TiO(2) nanoparticles caused the photocatalytic degradation of a typical TiO(2) substrate, methylene blue. The anti-E2 antibody immobilized on the TiO(2) surface recognized and bound E2 in the solution, thereby improving the efficiency of E2 degradation compared with that of PAA-TiO(2) nanoparticles. These results demonstrate that the E2Ab-PAA-TiO(2) nanoparticles developed in this study can be used in water treatment technology. Furthermore, this strategy of immobilizing proteins on nanoscale TiO(2) particles creates new applications not only in the treatment of environmental waste, but also in medical and public sanitation processes.     

A mixed dispatching rule approach in FMS scheduling

Short-term scheduling in flexible manufacturing systems (FMSs) is a difficult problem because of the complexities and dynamic behavior of FMSs. To solve this problem, a dispatching rule approach is widely used. In this approach, however, a single dispatching rule is usually assigned for all machines in a system during a given scheduling interval. In this paper, a mixed dispatching rule which can assign a different dispatching rule for each machine is proposed. A search algorithm which selects an appropriate mixed dispatching rule using predictions based on discrete event simulation is developed for this approach. The search algorithm for the mixed dispatching rule is described in detail. The effectiveness (in meeting performance criteria) of the mixed dispatching rule and the efficiency of the search algorithm relative to exhaustive search (complete enumeration) is demonstrated on an FMS model. The mixed dispatching rule approach performs up to 15.9% better than the conventional approach, and is 4% better on average. The statistical significance of the results is dicussed.     

Decolorization of methylene blue in aqueous suspensions of titanium peroxide

The pretreatment of TiO(2)-photocatalysts in solutions of H(2)O(2) was studied by examining the decolorization of methylene blue in the dark. Incubation of TiO(2) particles in H(2)O(2) solutions increased the oxidizing capacity of TiO(2). Methylene blue (0.3 mM) was degraded in the presence of pretreated TiO(2), and a decolorizing ratio of 47% was obtained after a 48-h incubation period in the presence of 5.0 g/L pretreated TiO(2). Titanium peroxide as a stable oxidant, which can be synthesized with the reaction of titanium sulfate and H(2)O(2), was studied in the decolorizing process of methylene blue. Concentrations of methylene blue were significantly reduced in the presence of titanium peroxide, and a greater extent of decolorization was obtained with larger amounts of titanium peroxide. A 63% decrease in methylene blue concentration was achieved in 5h incubation in the presence of 4.0 g/L titanium peroxide. H(2)O(2) accelerated the decolorizing process in the presence of titanium peroxide. The addition of 100 mM H(2)O(2) to a methylene blue solution containing 2.0 g/L titanium peroxide increased the decolorizing ratio to 85% after 5 h incubation. The addition of a hydroxyl radical scavenger, dimethyl sulfoxide, significantly decreased the decolorizing ratio, indicating the role of hydroxyl radicals in the oxidation process.     

Nonisothermal design of fluid segments for precise temperature control in microreactors

The present paper discusses the effects of the fluid segment size on reaction temperature as well as mixing performance in microreactors under nonisothermal conditions. In the reactors, exothermic parallel-series reaction systems having different ratio of activation energy proceeds with the cooling through walls of a fixed temperature. Reactant fluids are fed in the form of fluid segments. The width of fluid segment determines the diffusive mixing rate, and the height of fluid segment affects the cooling rate of reactant fluids. When the activation energy of the reaction producing the desired product is higher than that of the by-product, an optimum height to maximize the yield of the desired product exists with a fixed fluid segment width. This result indicates that the fluid segment size can be determined from the mixing rate and cooling rate. From the results on the reactor where reactants are mixed from the reactor inlet, even in a channel the scale of which is in the sub-millimeter range, suppressing hot spot is difficult when mixing and reaction are rapid and heats of reactions are large. For such reaction systems, mixing based on fluid segments is effective for controlling mixing and reaction rate.     

A high performance pMOSFET with two-step recessed SiGe-S/D structure for 32 nm node and beyond

A novel SiGe-S/D structure for high performance pMOSFET called two-step recessed SiGe-source/drain (S/D) is developed with careful optimization of recessed SiGe-S/D structure. With this method, hole mobility, short channel effect and S/D resistance in pMOSFET are improved compared with conventional recessed SiGe-S/D structure. To enhance device performance such as drain current drivability, SiGe region has to be closer to channel region. Then, conventional deep SiGe-S/D region with carefully optimized shallow SiGe SDE region showed additional device performance improvement without SCE degradation. As a result, high performance 24 nm gate length pMOSFET was demonstrated with drive current of 451 μA/μm at V_dd of 0.9 V and I_off of 100 nA/μm (552 μA/μm at V_dd of 1.0 V). Furthermore, by combining with V_dd scaling, we indicate the extendability of two-step recessed SiGe-S/D structure down to 15 nm node generation.     

Application of magnetic ribbon coated with poly(3,4‐ethylenedioxy‐thiophene)/poly(4‐styrenesulfonate) to a wireless humidity sensor

This paper describes a wireless humidity sensor that employs the mechanical resonance frequency, fr, change in a magnetic ribbon coated with poly(3,4‐ethylenedioxythiophene) doped with poly(4‐styrenesulfonate) (PEDOT/PSS). PEDOT/PSS expands or contracts by several percentage when it absorbs or desorbs water vapor, and so the curvature, 1/R, of the ribbon varies in response to changes in relative humidity, RH. It is also proved that fr is proportional to 1/R. Consequently, RH can be detected by monitoring the fr using a pickup coil placed away from the ribbon; fr changes from 68 kHz at RH = 87% to 148 kHz at RH = 0%. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.