Crosslinked acrylic pressure sensitive adhesives. 3. Effect of adherend on film formation

The reaction of isocyanate in pressure sensitive adhesive (PSA) films adhered on to various adherends having different surface tensions was monitored by depth profiling using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy.In the latter stages of crosslinking reaction, unreacted isocyanate and its derivatives exist more in the bulk of the PSA than in the interfaces between PSA and adherends which are Teflon sheet and PE film having relatively lower surface tensions. In the case of using stainless steel having relatively higher surface tension as adherend, opposite segregation was observed compared to Teflon and PE.From X-ray photoelectron spectroscopy (XPS), it was revealed that N atoms exist more in surface than in bulk when stainless steel is used as adherend. We conclude that polyisocyanates migrate in the PSA film in order to minimize the magnitude of interfacial free energy between the PSA and the adherend, which leads to the change of surface tension of PSA film.     

Activity measurement of gallium in the B2 phase of the CoGa–Sb system by the EMF method with zirconia-based solid electrolyte

Gallium activity in the B2 phase regions of both binary Co–Ga and ternary Co–Ga–Sb systems was measured by EMF method with stabilized zirconia solid electrolyte The temperature range was 1073–1273 K and Sb concentrations were 1, 2 and 3 mol fractions. Ga activity at 1173 and 1273 K increases sharply in Ga rich region and the addition of Sb to the CoGa phase increases Ga activity. Activity change corresponds to the lattice parameter change with Sb addition to the CoGa phase.     

Polytetrafluoroethylene processing characteristics using high-energy X-ray

Polytetrafluoroethylene (PTFE) microstructures’ processing characteristics using X-ray photo dcomposition and desorption are studied in the highest energy region (2 keV to >12 keV). While the exposed surface states are seen melting and boiling from the remaining bubble structure of the irradiated surface, basic photochemistry of PTFE is also same as previous reports and high-aspect ratio structures are successfully formed. We developed new Ni stencil electroformed stencil masks and successfully fabricated first and practical example of PTFE micro fluidic parts. The characteristics of fabricated micro fluidic parts, a PTFE fluid filter for vertical fluid flow operation which works as passive valve, agreed with the calculated results. This suggests that the accuracy of patterning is adequate to apply this technique to fabricate microfluidic parts and other various microparts.     

Enzyme-linked immunosorvent assay using vertical microreactor stack with microbeads

The advantages of vertical microreactor stack with three-dimensional (3D) structure for immunoassay are discussed. The vertical microreactor stack uses vertical fluid flow operation with multifunctional fluid filters. The multi function of fluid filter is very effective for micromixing and passive valve operation. The mechanism of micromixing is discussed by using computational fluid dynamics (CFD), and we know that the mixing mechanism based on Coanda effect. To evaluate the micromixing performance of fluid filter, we demonstrated enzyme reaction with unique repeat mixing operation. As the results, we proved that the fluid filter has very effective mixing performance. The detection limit, which demonstrated by competition enzyme-linked immunosorvent assay (ELISA), is comparable with recommended detection limit, which suggested by Japanese ministry for the environment.     

Development of an algorithm for corneal reshaping with a scanning laser beam

The corneal-ablation rate, the beam-intensity distribution, and the initial and the desired corneal topographies are used to calculate a spatial distribution map of laser pulses. The optimal values of the parameters are determined with a computer model, for a system that produces 213-nm radiation with a Gaussian beam-intensity distribution and a peak radiant exposure of 400 mJ/cm(2). The model shows that with a beam diameter of 0.5 mm, an overlap of 80%, and a 5-mm treatment zone, the roughness is less than 6% of the central ablation depth, the refractive error after correction is less than 0.1 D for corrections of myopia of 1, 3, and 6 D and less than 0.4 D for a correction of myopia of 10 D, and the number of pulses per diopter of correction is 2500 when the beam-intensity distribution is Gaussian and 580 when it is flat.     

Development of probe-to-probe approach method for an independently controlled dual-probe scanning tunneling microscope

We developed a method of fast probe-to-probe approach for an independently controlled dual-probe scanning tunneling microscope (STM), which is essential to measure the transport property of nanostructures, without scanning electron microscopy (SEM). In the approach method, inchworm motors are used as the coarse positioning devices, which are controlled with a personal computer. The method enables an automatic approach of the probe to the other probe within a short time (typically 30 min). After the approach, a real distance between contact points of each probe tip to a sample can be measured from the overlapped part of the STM images obtained with individual probe. The approach method without SEM is also useful to measure the charge transport in the atmosphere, which will be essential for measurement of the bio molecules.     

Development and Use of a Kinetical and Real-Time Monitoring System to Analyze the Replication of Hepatitis C Virus

In microbiological research, it is important to understand the time course of each step in a pathogen’s lifecycle and changes in the host cell environment induced by infection. This study is the first to develop a real-time monitoring system that kinetically detects luminescence reporter activity over time without sampling cells or culture supernatants for analyzing the virus replication. Subgenomic replicon experiments with hepatitis C virus (HCV) showed that transient translation and genome replication can be detected separately, with the first peak of translation observed at 3–4 h and replication beginning around 20 h after viral RNA introduction into cells. From the bioluminescence data set measured every 30 min (48 measurements per day), the initial rates of translation and replication were calculated, and their capacity levels were expressed as the sums of the measured signals in each process, which correspond to the areas on the kinetics graphs. The comparison of various HuH-7-derived cell lines showed that the bioluminescence profile differs among cell lines, suggesting that both translation and replication capacities potentially influence differences in HCV susceptibility. The effects of RNA mutations within the 5′ UTR of the replicon on viral translation and replication were further analyzed in the system developed, confirming that mutations to the miR-122 binding sites primarily reduce replication activity rather than translation. The newly developed real-time monitoring system should be applied to the studies of various viruses and contribute to the analysis of transitions and progression of each process of their life cycle.     

Theoretical high-efficiency extraction study of a short-pulseelectron-beam-pumped ArF laser amplifier with atmospheric pressureAr-rich mixtures

The single-pass (50 cm) amplifier performance of an atmospheric-pressure ArF laser pumped by a 65-ns full-width-at-half-maximum short-pulse electron beam was investigated theoretically for a wide range of excitation rates (0.1-2.0 MW/cm³ ). Atmospheric mixtures of Ne, Ar, and F₂ (three mixtures of Ar=40%, 70%, and Ne-free) were studied. A kinetic numerical model of the ArF amplifier with a Ne buffer system was constructed. A one-dimensional propagation treatment considered the gain depletion and saturation absorption spatially and temporally along the optical axis. In this model the rate constants for electron quenching of ArF* of 1.6×10^-7, 1.9×10^-7, and 2.4×10 ^-7 cm³/s were used for Ar concentration of 40, 70 percent, and Ar/F₂ mixture, respectively     

Evaluation of Young’s modulus of imprinted hydrogen silsesquioxane pillar after residual layer removal by reactive ion etching

Nanoimprint lithography has two basic steps. The first is the imprint step in which a mold with nanostructures on its surface is pressed into a resin film on a substrate, followed by removal of the mold. The second step is the residual layer removal by a reactive ion etching (RIE). There is no report whether the properties of the imprinted structure after RIE change or not. In this work, the authors evaluated the Young’s modulus of the imprinted pillar after residual layer removal by RIE. In this experiment, hydrogen silsesquioxane (HSQ), a type of spin-on-glass, was used as an imprint material. The residual layer was etched by RIE using CHF₃ gas. The Young’s modulus of imprinted pillar after RIE was measured via cantilever method. The Young’s modulus of HSQ pillar after RIE was twice as much as that of HSQ pillar before RIE. From the Fourier transform infrared measurement, it was founds the chemical structure of HSQ was changed by forming network structure due to heating by RIE plasma energy. These results indicate that the mechanical property of imprinted structure was changed in the residual layer removal step by using RIE.