A highly integrated 40-MIPS (peak) 64-b RISC microprocessor

A 1-million transistor 64-b microprocessor has been fabricated using 0.8-μm double-metal CMOS technology. A 40-MIPS (million instructions per second) and 20-MFLOPS (million floating-point operations per second) peak performance at 40 MHz is realized by a self-clocked register file and two translation lookaside buffers (TLBs) with word-line transition detection circuits. The processor contains an integer unit based on the SPARC (scalable processor architecture) RISC (reduced instruction set computer) architecture, a floating-point unit (FPU) which executes IEEE-754 single- and double-precision floating-point operations a 6-KB three-way set-associative physical instruction cache, a 2-KB two-way set-associative physical data cache, a memory management unit that has two TLBs, and a bus control unit with an ECC (error-correcting code) circuit     

Surfactant effects on hydrate formation in an unstirred gas/liquid system: An experimental study using HFC-32 and sodium dodecyl sulfate

This paper deals with the effects of a surfactant additive on the formation of a clathrate hydrate in a quiescent guest-gas/liquid-water system. The paper first presents our strong suspicion against the existing hypothesis that the surfactant-micelle formation in the liquid-water phase promotes the hydrate formation. It is pointed out that the Krafft point for sodium dodecyl sulfate (SDS), a popular anionic surfactant often used in previous hydrate-forming experiments, is presumably higher than the system temperatures set in these experiments and hence that no micelles may have formed in these experiments. The paper then describes our experimental observations of the hydrate formation from a hydrofluorocarbon gas, HFC-32 (CH₂F₂), to show how the hydrate formation behavior is affected by the addition of SDS to the water when brought into contact with HFC-32. In each experiment, HFC-32 gas was continuously supplied to a rectangular chamber partially filled with a quiescent pool of water (pure water or an aqueous SDS solution) to compensate for the gas consumption due to the hydrate formation, thereby maintaining a constant pressure inside the chamber. The present experiments featured the following characteristics: (a) detailed visual observations along horizontal axes through large side windows in the test chamber, and (b) surface tension measurements of the aqueous SDS solutions with the aid of a pendant-drop device inserted in the same chamber to determine the SDS-in-water solubility, which seems to have been misunderstood as the critical micelle concentration (CMC) in some previous studies, under the hydrate-forming conditions. The former revealed that the addition of SDS to the pool-forming water results in the formation of thick, highly porous hydrate layers not only on the liquid-pool surface but also on the chamber walls above the level of the pool surface, leaving the bulk of the liquid pool free from hydrate crystals. The latter led to an important finding that the SDS concentration at which the rate of the hydrate formation peaks is slightly lower than the solubility (the false CMC). An excessive addition of SDS beyond the solubility was found to cause a decrease in the rate of hydrate formation but an increase in the final level of the water-to-hydrate conversion.     

Selective conversion of CO into methanol at ordinary temperature, part 5. Using an electrochemical photocell

Carbon monoxide has been selectively converted to methanol by means of an electrochemical photocell composed of the n-CdS photoanode and the Everitt's salt-modified platinum cathode. The catholyte was the CO-saturated aqueous solution containing a metal complex and a primary alcohol operating as homogeneous catalysts. In the anolyte, various reducing agents were added to reduce the holes created at the semiconductor. The current efficiency of the methanol formation was almost 100%, irrespective of the kind of metal complex if the reducing agent added as a hole scavenger to the anolyte has a sufficiently negative redox potential.     

Roles of a neuronal cell-surface molecule, neuropilin, in nerve fiber fasciculation and guidance

PURPOSE: To determine whether infiltrative lung, airway, or vascular disease can be differentiated as the cause of mosaic attenuation on thin-section computed tomographic (CT) scans of the lung. MATERIALS AND METHODS: Thin-section CT scans were reviewed in 70 patients examined at three institutions. A mosaic attenuation pattern and pathologic or clinical proof of a specific type of disease were demonstrated. Causes of the mosaic pattern included infiltrative lung disease (n = 37), airway disease (n = 22), and vascular disease (n = 11). Thin-section CT findings were assessed independently by two observers blinded to clinical findings. RESULTS: The type of disease was identified correctly at CT in 58 (83%) of 70 patients by observer 1 and 57 (81%) of 70 patients by observer 2. Infiltrative lung disease was diagnosed correctly by both observers in 34 (92%) of 37 cases. Observer 1 identified 21 (95%) of 22 cases of airway disease and three (27%) of 11 cases of vascular disease. Observer 2 identified 19 (86%) of 22 cases of airway disease and four (36%) of 11 cases of vascular disease. CONCLUSION: Infiltrative lung disease and airway disease may be differentiated reliably as the cause of mosaic attenuation on lung CT scans, whereas vascular disease is often misinterpreted as infiltrative lung disease or airway disease.     

A 144-Mb, eight-level NAND flash memory with optimized pulsewidthprogramming

We report a fast-programming, compact sense and latch (SL) circuit to realize an eight-level NAND flash memory. Fast programming is achieved by supplying optimized voltage and pulsewidth to the bit lines, according to the programming data. As a result, all data programming is completed almost simultaneously, and 0.67-MB/s program throughput, which is 1.7 times faster than conventional program throughput, is achieved. The compact layout of the SL circuit is made possible by four 3-bit latches sharing one unit of the read/verify control circuit. Using these techniques, we fabricated a 144-Mb, eight-level NAND flash memory using a 0.35-μm CMOS process, resulting in a 104.2-mm² die size and a 1.05-μm² effective cell size     

Selective sorption of heavy metal thiocyanate complexes on crown ether resin

The sorption behavior of heavy metal thiocyanate complexes was investigated for dibenzo-18-crown-6 (DB18C6) resin and bis[2-(o-methoxyphenoxy)ethyl]ether (BMPE) resin. The DB18C6 resin showed a high sorption ability and the degree of zinc sorption increased significantly with thiocyanate concentration. This behavior was not observed for BMPE resin. The sorption behavior was influenced by the countercation species, and the degree of sorption of zinc ions showed the maximum when the potassium thiocyanate was used as a complexing salt. The sorbed species appear to be KZn(SCN)₃, K₂Zn(SCN)₄ in the potassium thiocyanate system, and Zn(SCN)₂ in the lithium thiocyanate system, respectively, according to analysis of the sorption equilibrium. Sodium and ammonium thiocyanate systems show an intermediate behavior of the two. The sorption selectivity for DB18C6 resin depended not only on the hydrophobic nature of heavy metal thiocyanate complexes but also on the stabilization of counter cation species with crown ether matrix, and the sorption selectively was found to be effectively controlled by countercation species according to the cation-chelation mechanism.