Yoshishige Endo

A study of antireflective and antistatic coating with ultrafine particles

Abstract A new antireflective and antistatic coating with ultrafine particles is developed. The coating consisted of two layers based on an antireflective layer of SiO 2 ultrafine particles that is uniformly a single particle thick and a conductive layer composed of multiple SnO 2 ultrafine particles. The outer surface of the antireflective layer is alternately concave convex, owing to the arrangement of SiO 2 particles. The refractive index of this layer therefore decreases gradually from its inner to its outer surface. Thus, the total reflectivity can be reduced. The coating provides low reflectivity and electrical resistance in addition to high resolution and contrast.

Optimization of Chemical Reaction Processes in Microreactors Using Reaction Rate Analyses

We applied microreactors to the three following reactions: a consecutive bromination reaction, the two-step Sandmeyer reaction, and an acetylation reaction including solvent effects. We obtained the reaction rate constants from few experimental data or quantum chemical calculations and optimized the reaction conditions such as the reaction times and temperature. We then experimentally validated them by microreactors. A consecutive bromination reaction, where the objective reaction was followed by the side reaction, was one of the processes. The reaction temperature played an important role in the effects of a microreactor. The yield of the objective product was improved by about 40% using a microreactor. The two-step Sandmeyer reaction was also applied, where the 1st-step reaction was followed by the 2nd-step reaction to produce the objective product. The 1st-step reaction had the diffusion-controlled process, while the 2nd-step reaction had the reaction-controlled one. The yield of the objective product was improved when microreactors were used and the reaction time for the 2nd-step reaction was set appropriately. Moreover, an acetylation reaction including solvent effects on reaction rates was considered and the solvent effects could be predicted from quantum chemical calculations. The calculation suggested that acetic acid with the larger electron-accepting property gave more stability to the species formed in the transition state. The reaction time was shortened using a microreactor, when the reaction process was changed from reaction-controlled to diffusion-controlled by changing the solvent used.Copyright

Prediction of Chemical Reaction Yield in a Microreactor and Development of a Pilot Plant Using the Numbering-Up of Microreactors

The chemical reaction yield was predicted by using Monte Carlo simulation. The targeted chemical reaction of a performance evaluation using the microreactor is the consecutive reaction. The main product P1 is formed in the first stage with the reaction rate constant k1. Moreover, the byproduct P2 is formed in the second stage with the reaction rate constant k2. It was found that the yield of main product P1 was improved by using a microreactor when the ratio of the reaction rate constants became k1/k2 >1. To evaluate the Monte Carlo simulation result, the yields of the main products obtained in three consecutive reactions. It was found that the yield of the main product in cased of k1/k2 >1 increased when the microreactor was uesd. Next, a pilot plant involving the numbering-up of 20 microreactors was developed. The 20 microreactor units were stacked in four sets, each containing five microreactor units arranged. The maximum flow rate when 20 microreactors were used was 1 × 104 mm3 /s, which corresponds to 72 t/year. Evaluation of the chemical performance of the pilot plant was conducted using a nitration reaction. The pilot plant was found to capable of increasing the production scale without decreasing the yield of the products.Copyright

Study of the process for forming microscopic surface bumps with ultra-fine particles

Abstract The flying height of magnetic heads in hard disk drives has been markedly reduced in proportion to an increase in the recording density, resulting in a large head-disk stiction. One of the techniques for overcoming this problem is to use laser texturing. The laser can create bumps with a typical height of 20-30 nm and a diameter of 10 μm, although a small bump diameter is needed to obtain better tribological performance. We therefore studied a precise bump diameter control process with ultra-fine particles (UFPs) of SiO 2 and a dry etching process. UFPs of 0.3 μm diameter were coated on a disk surface by dipping or an ink-jet method and the surface was etched by oxygen. After removing the UFPs, the bumps formed were measured to have a height of 10-20 nm and a diameter of 0.21 μm. The diameter was about the same as that of the UFPs.