Improvement of plasma etching durability of positive working resist by copolymerization,blending, and crosslinking

The plasma etching durability of O₂ and CCl₄ was investigated for copolymer and polymer blend of poly(methyl methacrylate) (PMMA) and poly(α-methylstyrene) (PMSt) as a function of MSt content. Further, the effects of crosslinking on plasma etching were studied by incorporating N-methylolated methacrylamide into the copolymer as a crosslinkable site during prebaking. The plasma-etching resistance of PMMA was largely improved by incorporating or adding only a small amount of MSt. Especially in the case of the CCl₄ plasma etching, the copolymer and the polymer blend with 10 mol% of MSt showed etching resistance as great as that of PMSt homopolymer. Stabilization of the polymers against the plasma etching can be explained by the sponge effect, the energy migration followed by the quenching by the phenyl ring. The polymer blend offered similar etching resistance as the copolymer, indicating an effective occurrence of the energy migration between the polymer chains. Etching resistance was also improved by crosslinking, also due to the enhancement of the sponge effect.     

Silica-based mesoporous molecular sieves derived from a layered polysilicate kanemite—A review

Synthesis of highly ordered mesoporous materials derived from a layered polysilicate kanemite has been reviewed. Silica-surfactant mesostructured materials are obtained by the reaction of kanemite with alkyltrimethy lammonium ions. Calcination of silica-surfactant mesophase materials yields ordered mesoporous molecular sieves. Substantial replacement of alkyltrimethylammonium ions for interlayer Na ions and careful adjustment of pH in the reaction media are necessary for the preparation of ordered mesoporous silica. Formation processes of the silicate-surfactant mesophase materials have been monitored by in-situ powder X-ray diffraction technique which has indicated the presence of a lamellar phase before the appearance of a hexagonal phase. Comparison of these materials with MCM-41 is briefly mentioned. The properties and potential applications of these materials are also briefly outlined.     

A 68-ns 4-Mbit CMOS EPROM with high-noise-immunity design

In a VLSI memory, noise generated by its own operation is a serious problem. The noise disturbs data sensing, especially in EPROMs which have a single-ended sensing scheme. To develop high-density and high-speed EPROMs, it is necessary to solve the noise problems. Incorrect EPROM functions due to the noise are discussed. High-noise-immunity circuit techniques for stable data sensing and high-speed access time are proposed. These are divided bit-line layout, reference line with dummy bit lines, and a chip-enable transition detector. Using these circuit techniques and 0.8-μm n-well CMOS technology, a 512 K×8-b CMOS EPROM was developed. A 68-ns access time was achieved. The die size is 5.62 mm×15.30 mm, and it is assembled in a 600-mil cerdip package     

Molecular evidence from retroposons that whales form a clade within even-toed ungulates

The origin of whales and their transition from terrestrial life to a fully aquatic existence has been studied in depth. Palaeontological, morphological and molecular studies suggest that the order Cetacea (whales, dolphins and porpoises) is more closely related to the order Artiodactyla (even-toed ungulates, including cows, camels and pigs) than to other ungulate orders. The traditional view that the order Artiodactyla is monophyletic has been challenged by molecular analyses of variations in mitochondrial and nuclear DNA. We have characterized two families of short interspersed elements (SINEs) that were present exclusively in the genomes of whales, ruminants and hippopotamuses, but not in those of camels and pigs. We made an extensive survey of retropositional events that might have occurred during the divergence of whales and even-toed ungulates. We have characterized nine retropositional events of a SINE unit, each of which provides phylogenetic resolution of the relationships among whales, ruminants, hippopotamuses and pigs. Our data provide evidence that whales, ruminants and hippopotamuses form a monophyletic group.     

Individual identification of cadaver parts after a bomb explosion using oligonucleotide fingerprinting by (GTG)5

A blind shell suddenly and unexpectedly exploded, and 20 dismembered human remains were discovered. DNA fingerprint was performed to determine whether the 20 human remains were derived from one person or not. DNA was isolated from each of the remains and digested by the restriction enzyme Hinf I and Hae III and hybridized with the oligonucleotide probe (GTG)5. DNA fingerprint using Hinf I demonstrated the same band pattern in 17 out of the 20 remains. However, in the remaining 3 samples, two novel strange bands were observed. DNA fingerprint using Hae III showed completely identical pattern in all of the remains.     

Application of a two-degrees-of-freedom controller to chaotic dynamical systems

We apply a TDOF (two-degrees-of-freedom) robust controller to chaotic dynamical systems. We show that the TDOF controller is effective not only for rejection of chaotic disturbance but also for control of a chaotic plant.     

Multifault calculation method for dynamic stability study of electric power systems

For the fault condition in dynamic stability study, balanced faults have mainly been utilized. Recently, however, with the progress of system protective control technologies such as the multiphase reclosing system for a faulted transmission line, the needs for stability software which would be able to calculate simultaneous faults without any restrictions on fault types, total numbers or location, have been increasing. This report presents the newly developed multifault calculation method based on symmetrical components which is able to calculate simultaneous faults without any restrictions on combination of fault types, and total numbers or location. Fault types consist of balanced/ unbalanced ground fault, short-circuit fault, line-out of transmission lines, and short-circuit of series condenser. The proposed method also allows for calculation of faults at an arbitrary location on the line without any topological changes of each symmetrical network even if the faults include line-end faults with ensuring outages. An example was shown to clarify the validity of the proposed method. Moreover, transient stability limits under the various fault conditions also were discussed.     

A 500-megabyte/s data-rate 4.5 M DRAM

A 512-kb×9 DRAM with a 500-Mbyte/s data transfer rate was developed. This high data rate was achieved by designing a DRAM core with a very high internal column bandwidth, and coupling this core with a block-oriented, small-swing, synchronous interface that uses skew-canceling clocks. The DRAM has a 1-kbyte×2-line sense-amp cache and is assembled in a 32-pin vertical surface-mount-type plastic package. The measurement results clearly verified the 500-Mbyte/s data rate