Catalytic Reduction of Nitrogen Oxides in Automotive Exhaust Containing Excess Oxygen by NOx Storage-Reduction Catalyst

Automotive catalyst technology is now faced with very difficult problems. As a result of automakers' efforts to produce more efficient and lower-emission vehicles, lean-burn gasoline engines have been introduced into the market. While these are much more efficient than the conventional engines, the NOx removal has become significantly more difficult. After enormous efforts, we succeeded to solve the problem by inventing a new class of catalyst. Here, our challenge to develop the new catalyst that stores and then reduces NOx is described. The catalyst made it possible for emissions of lean-burn engines to meet the strict NOx regulations.     

Polymerization of formaldehyde and the physical properties of the polymerization products. I.

Polymerization of formaldehyde carried out in the solution method and gas supply method using various initiators at various temperatures and characterization of the polyoxymethylene obtained are discussed. In both modes of polymerization, polyoxymethylenes with sufficient molecular weight (M?_n) and small M?_w/M?_n were obtained. The toughness of polymer as determined by the M?_w/M?_n of the polymer with sufficient M_n was confirmed.     

Analysis of turbine generator steady-state reactances for load conditions

This paper describes variations of turbine generator steady-state reactances for load conditions. When the turbine generator is of small size, magnetic saturation of the stator and rotor core is a problem. Therefore, it is important to understand the variations of the reactances for load conditions. The reactances of a 592-MVA turbine generator are calculated with d- and q-axis equations considering magnetic saturation and two-dimensional numerical magnetic field analysis. The results are as follows. (1) The equivalent synchronous reactances considering cross-magnetizing are smaller than the original synchronous reactances for load conditions. (2) Numerical values of the d- and q-axis mutual reactance and the field and q-axis mutual reactance are at their maximum when the d-axis linkage flux is nearly equal to the q-axis linkage flux under constant voltage. (3) The d-axis synchronous reactance drops with increasing reactive power under constant voltage and active power, but the q-axis synchronous reactance increases. (4) The variation of the equivalent d-axis synchronous reactance with increasing reactive power is similar to that of the d-axis synchronous reactance, but the variation of the equivalent q-axis synchronous reactance is different from that of the q-axis synchronous reactance. © 1998 Scripta Technica. Electr Eng Jpn, 123(3): 73–83, 1998     

High resolution for single-strand conformation polymorphism analysis by capillary electrophoresis

Since the successful completion of the Human Genome Project, increasing concern is being directed toward the polymorphic aspect of the genome and its clinical relevance. A form of single-strand DNA-conformation polymorphism analysis (SSCP) employing nondenaturing slab-gel electrophoresis (SGE) is applicable to the genetic diagnosis of bladder cancer from urine samples. To bring this technique into routine clinical practice, the use of capillary electrophoresis (CE) is naturally favorable in terms of speed and automation. However, the resolving power of SSCP, a prerequisite basis for reliability required in diagnostics, remains as a challenge for CE systems. We thus focused on this topic and conducted studies on CE instruments equipped with a single capillary or an array of multiple capillaries, using the resolution (Rs) as a quantitative scale for the resolving power. Polymer concentration and buffer are shown to be the decisive parameters. High Rs values of >2.5 are achieved for representative SNPs markers under the optimized conditions, without sacrificing such intrinsic advantages of CE over SGE as the 10-fold quicker migration time and operation that is reproducible, continuous, and automatic. The strategies presented broaden the limits of CE in both the current and related applications.     

NOx Storage-Reduction Three-Way Catalyst with Improved Sulfur Tolerance

The NO _x storage-reduction catalyst (NSR catalyst) is poisoned by SO₂ caused by fuel sulfur, thus its activity is reduced. In order to improve the NSR catalyst, the sulfur poisoning phenomenon has been analyzed. Based on this result, we developed TiO₂ and Rh/ZrO₂ to promote the sulfur desorption. The developed catalyst has made remarkable progress in its sulfur tolerance, about 50% improvement in NO _x purification performance compared with the conventional one.     

Development of a distributed power outage scheduling system by using bee‐gent

The Power Outage Scheduling Problem is a distributed constraint satisfaction problem in which scattered local power stations have to make schedules that are consistent with one another. However, synchronous backtrack algorithms, a well‐known method for distributed constraint satisfaction problems, have difficulty handling rapid schedule adjustments and impartial assignment of power station schedules. Thus, we propose two kinds of heuristics: parallel assignment and multiple priority strategies. We also developed a distributed system for the power outage scheduling problem which makes use of the above heuristics in order to ensure efficiency. The system is based on Bee‐gent (Bonding and Encapsulation Enhancement aGENT framework) and consists of schedulers for each power station and mediation agents which have cloning and merging functions to support the implementation of the heuristics. The result of the experiment shows an improvement when handling rapid adjustment and impartiality issues and indicates that this improvement is provided with reasonable computational overhead. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 139(3): 62–72, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.1161     

Functional and heterologous expression of human protein O-linked mannose β-1,2-N-acetylglucosaminyltransferase 1 in zebrafish

Although membrane-associated proteins are related to many diseases and are important targets for drug discovery, their expression is often difficult in bacterial hosts such as Escherichia coli. To overcome this limitation, here, we focused on a novel host-vector system in zebrafish for the expression of human protein O-linked mannose β-1,2-N-acetylglucosaminyltransferase 1 (hPOMGnT1) which is related to muscle-eye-brain disease. For the expression of hPOMGnT1, the vector pZex-EGFP-pXI-hPOMGnT1 was constructed and injected into fertilized eggs. Using this system, we demonstrated that recombinant hPOMGnT1 was successfully expressed in the whole bodies of zebrafish embryos.     

Laser cutting performances for thick steel specimens studied by molten metal removal conditions

Laser cutting performances for thick carbon steel and stainless steel specimens up to 300 mm in thickness were studied to dismantle large steel objects. The cutting performances were summarized based on the assist gas flow rate and the front kerf width, and the range for appropriate cutting conditions was shown. Gas pressure in the kerf region required for molten metal removal was estimated from the pressure loss on the kerf surface, which depended on the gas flow rate and the kerf width. The relation to keep sufficient gas pressure in the kerf well corresponded to the experimental relations for appropriate cutting. Drag force to the molten metal on the kerf surface was also estimated, which varied by the structures and materials. The behaviors such as cavity formation and its expansion in the kerf region at the unsuccessful cutting trials were well explained. The results are informative for the development of the laser cutting technology applied to the thick steel specimen for the nuclear decommissioning.     

Video OCR: indexing digital news libraries by recognition of superimposed captions

The automatic extraction and recognition of news captions and annotations can be of great help locating topics of interest in digital news video libraries. To achieve this goal, we present a technique, called Video OCR (Optical Character Reader), which detects, extracts, and reads text areas in digital video data. In this paper, we address problems, describe the method by which Video OCR operates, and suggest applications for its use in digital news archives. To solve two problems of character recognition for videos, low-resolution characters and extremely complex backgrounds, we apply an interpolation filter, multi-frame integration and character extraction filters. Character segmentation is performed by a recognition-based segmentation method, and intermediate character recognition results are used to improve the segmentation. We also include a method for locating text areas using text-like properties and the use of a language-based postprocessing technique to increase word recognition rates. The overall recognition results are satisfactory for use in news indexing. Performing Video OCR on news video and combining its results with other video understanding techniques will improve the overall understanding of the news video content.     

A process development for the bundling crystallization of aspartame

It is known that rod-like crystals of aspartame, in which several needle crystals appear to be bundled together (bundle-like crystals), have remarkably improved physical properties compared to the crystals obtained from a conventional stirred crystallizer. A crystallization process for obtaining bundle-like crystals has been developed for manufacturing practice. The conditions to obtain the bundle-like crystals are that crystallization must be carried out without stirring, with a high initial concentration of aspartame so that the amount of precipitated solid after cooling is about 10 g litre^?1 or more, and with rapid cooling to produce high supersaturation. A new type of crystallizer was developed for large-scale crystallization under these conditions. The pilot plant work was carried out in a 400-litre crystallizer, and it has been demonstrated that the crystallization process is technically possible and economically successful in the large-scale manufacturing of aspartame.